port jingle rtp connection

app/build.gradle

@@ -109,6 +109,10 @@ dependencies {
     // XMPP Address library
     implementation 'org.jxmpp:jxmpp-jid:1.0.3'
 
+    // WebRTC
+    implementation 'im.conversations.webrtc:webrtc-android:104.0.0'
+
+
     // Consistent Color Generation
     implementation 'org.hsluv:hsluv:0.2'
 
@@ -116,15 +120,19 @@ dependencies {
     // DNS library (XMPP needs to resolve SRV records)
     implementation 'de.measite.minidns:minidns-hla:0.2.4'
 
+
     // Guava
     implementation 'com.google.guava:guava:31.1-android'
 
+
     // HTTP library
     implementation "com.squareup.okhttp3:okhttp:4.10.0"
 
+
     // JSON parser
     implementation 'com.google.code.gson:gson:2.10.1'
 
+
     // logging framework + logging api
     implementation 'org.slf4j:slf4j-api:1.7.36'
     implementation 'com.github.tony19:logback-android:2.0.1'

app/src/main/AndroidManifest.xml

@@ -106,6 +106,11 @@
         <activity
             android:name="im.conversations.android.ui.activity.SetupActivity"
             android:windowSoftInputMode="adjustResize" />
+        <activity
+            android:name=".ui.activity.RtpSessionActivity"
+            android:autoRemoveFromRecents="true"
+            android:launchMode="singleInstance"
+            android:supportsPictureInPicture="true" />
     </application>
 
 </manifest>

app/src/main/java/eu/siacs/conversations/Config.java

@@ -0,0 +1,10 @@
+package eu.siacs.conversations;
+
+import android.net.Uri;
+
+public class Config {
+    public static final String LOGTAG = "conversations";
+    public static final Uri HELP = Uri.parse("https://help.conversations.im");
+    public static final boolean REQUIRE_RTP_VERIFICATION =
+            false; // require a/v calls to be verified with OMEMO
+}

app/src/main/java/eu/siacs/conversations/generator/MessageGenerator.java

@@ -0,0 +1,54 @@
+package eu.siacs.conversations.generator;
+
+import eu.siacs.conversations.xmpp.jingle.JingleRtpConnection;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import im.conversations.android.xmpp.manager.JingleConnectionManager;
+import im.conversations.android.xmpp.model.stanza.Message;
+import org.jxmpp.jid.Jid;
+
+public final class MessageGenerator {
+
+    private MessageGenerator() {
+        throw new IllegalStateException("Do not instantiate me");
+    }
+
+    public static Message sessionProposal(
+            final JingleConnectionManager.RtpSessionProposal proposal) {
+        final Message packet = new Message(Message.Type.CHAT); // we want to carbon copy those
+        packet.setTo(proposal.with);
+        packet.setId(JingleRtpConnection.JINGLE_MESSAGE_PROPOSE_ID_PREFIX + proposal.sessionId);
+        final Element propose = packet.addChild("propose", Namespace.JINGLE_MESSAGE);
+        propose.setAttribute("id", proposal.sessionId);
+        for (final Media media : proposal.media) {
+            propose.addChild("description", Namespace.JINGLE_APPS_RTP)
+                    .setAttribute("media", media.toString());
+        }
+
+        packet.addChild("request", "urn:xmpp:receipts");
+        packet.addChild("store", "urn:xmpp:hints");
+        return packet;
+    }
+
+    public static Message sessionRetract(
+            final JingleConnectionManager.RtpSessionProposal proposal) {
+        final Message packet = new Message(Message.Type.CHAT); // we want to carbon copy those
+        packet.setTo(proposal.with);
+        final Element propose = packet.addChild("retract", Namespace.JINGLE_MESSAGE);
+        propose.setAttribute("id", proposal.sessionId);
+        propose.addChild("description", Namespace.JINGLE_APPS_RTP);
+        packet.addChild("store", "urn:xmpp:hints");
+        return packet;
+    }
+
+    public static Message sessionReject(final Jid with, final String sessionId) {
+        final Message packet = new Message(Message.Type.CHAT); // we want to carbon copy those
+        packet.setTo(with);
+        final Element propose = packet.addChild("reject", Namespace.JINGLE_MESSAGE);
+        propose.setAttribute("id", sessionId);
+        propose.addChild("description", Namespace.JINGLE_APPS_RTP);
+        packet.addChild("store", "urn:xmpp:hints");
+        return packet;
+    }
+}

app/src/main/java/eu/siacs/conversations/services/AppRTCAudioManager.java

@@ -0,0 +1,660 @@
+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+package eu.siacs.conversations.services;
+
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.PackageManager;
+import android.media.AudioDeviceInfo;
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.media.AudioRecord;
+import android.media.MediaRecorder;
+import android.os.Build;
+import android.util.Log;
+import androidx.annotation.Nullable;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.utils.AppRTCUtils;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.concurrent.CountDownLatch;
+import org.webrtc.ThreadUtils;
+
+/** AppRTCAudioManager manages all audio related parts of the AppRTC demo. */
+public class AppRTCAudioManager {
+
+    private static CountDownLatch microphoneLatch;
+
+    private final Context apprtcContext;
+    // Contains speakerphone setting: auto, true or false
+    @Nullable private SpeakerPhonePreference speakerPhonePreference;
+    // Handles all tasks related to Bluetooth headset devices.
+    private final AppRTCBluetoothManager bluetoothManager;
+    @Nullable private final AudioManager audioManager;
+    @Nullable private AudioManagerEvents audioManagerEvents;
+    private AudioManagerState amState;
+    private boolean savedIsSpeakerPhoneOn;
+    private boolean savedIsMicrophoneMute;
+    private boolean hasWiredHeadset;
+    // Default audio device; speaker phone for video calls or earpiece for audio
+    // only calls.
+    private AudioDevice defaultAudioDevice;
+    // Contains the currently selected audio device.
+    // This device is changed automatically using a certain scheme where e.g.
+    // a wired headset "wins" over speaker phone. It is also possible for a
+    // user to explicitly select a device (and overrid any predefined scheme).
+    // See |userSelectedAudioDevice| for details.
+    private AudioDevice selectedAudioDevice;
+    // Contains the user-selected audio device which overrides the predefined
+    // selection scheme.
+    // TODO(henrika): always set to AudioDevice.NONE today. Add support for
+    // explicit selection based on choice by userSelectedAudioDevice.
+    private AudioDevice userSelectedAudioDevice;
+    // Proximity sensor object. It measures the proximity of an object in cm
+    // relative to the view screen of a device and can therefore be used to
+    // assist device switching (close to ear <=> use headset earpiece if
+    // available, far from ear <=> use speaker phone).
+    @Nullable private AppRTCProximitySensor proximitySensor;
+    // Contains a list of available audio devices. A Set collection is used to
+    // avoid duplicate elements.
+    private Set<AudioDevice> audioDevices = new HashSet<>();
+    // Broadcast receiver for wired headset intent broadcasts.
+    private final BroadcastReceiver wiredHeadsetReceiver;
+    // Callback method for changes in audio focus.
+    @Nullable private AudioManager.OnAudioFocusChangeListener audioFocusChangeListener;
+
+    private AppRTCAudioManager(
+            Context context, final SpeakerPhonePreference speakerPhonePreference) {
+        Log.d(Config.LOGTAG, "ctor");
+        ThreadUtils.checkIsOnMainThread();
+        apprtcContext = context;
+        audioManager = ((AudioManager) context.getSystemService(Context.AUDIO_SERVICE));
+        bluetoothManager = AppRTCBluetoothManager.create(context, this);
+        wiredHeadsetReceiver = new WiredHeadsetReceiver();
+        amState = AudioManagerState.UNINITIALIZED;
+        this.speakerPhonePreference = speakerPhonePreference;
+        if (speakerPhonePreference == SpeakerPhonePreference.EARPIECE && hasEarpiece()) {
+            defaultAudioDevice = AudioDevice.EARPIECE;
+        } else {
+            defaultAudioDevice = AudioDevice.SPEAKER_PHONE;
+        }
+        // Create and initialize the proximity sensor.
+        // Tablet devices (e.g. Nexus 7) does not support proximity sensors.
+        // Note that, the sensor will not be active until start() has been called.
+        proximitySensor =
+                AppRTCProximitySensor.create(
+                        context,
+                        // This method will be called each time a state change is detected.
+                        // Example: user holds his hand over the device (closer than ~5 cm),
+                        // or removes his hand from the device.
+                        this::onProximitySensorChangedState);
+        Log.d(Config.LOGTAG, "defaultAudioDevice: " + defaultAudioDevice);
+        AppRTCUtils.logDeviceInfo(Config.LOGTAG);
+    }
+
+    public void switchSpeakerPhonePreference(final SpeakerPhonePreference speakerPhonePreference) {
+        this.speakerPhonePreference = speakerPhonePreference;
+        if (speakerPhonePreference == SpeakerPhonePreference.EARPIECE && hasEarpiece()) {
+            defaultAudioDevice = AudioDevice.EARPIECE;
+        } else {
+            defaultAudioDevice = AudioDevice.SPEAKER_PHONE;
+        }
+        updateAudioDeviceState();
+    }
+
+    /** Construction. */
+    public static AppRTCAudioManager create(
+            Context context, SpeakerPhonePreference speakerPhonePreference) {
+        return new AppRTCAudioManager(context, speakerPhonePreference);
+    }
+
+    public static boolean isMicrophoneAvailable() {
+        microphoneLatch = new CountDownLatch(1);
+        AudioRecord audioRecord = null;
+        boolean available = true;
+        try {
+            final int sampleRate = 44100;
+            final int channel = AudioFormat.CHANNEL_IN_MONO;
+            final int format = AudioFormat.ENCODING_PCM_16BIT;
+            final int bufferSize = AudioRecord.getMinBufferSize(sampleRate, channel, format);
+            audioRecord =
+                    new AudioRecord(
+                            MediaRecorder.AudioSource.MIC, sampleRate, channel, format, bufferSize);
+            audioRecord.startRecording();
+            final short[] buffer = new short[bufferSize];
+            final int audioStatus = audioRecord.read(buffer, 0, bufferSize);
+            if (audioStatus == AudioRecord.ERROR_INVALID_OPERATION
+                    || audioStatus == AudioRecord.STATE_UNINITIALIZED) available = false;
+        } catch (Exception e) {
+            available = false;
+        } finally {
+            release(audioRecord);
+        }
+        microphoneLatch.countDown();
+        return available;
+    }
+
+    private static void release(final AudioRecord audioRecord) {
+        if (audioRecord == null) {
+            return;
+        }
+        try {
+            audioRecord.release();
+        } catch (Exception e) {
+            // ignore
+        }
+    }
+
+    /**
+     * This method is called when the proximity sensor reports a state change, e.g. from "NEAR to
+     * FAR" or from "FAR to NEAR".
+     */
+    private void onProximitySensorChangedState() {
+        if (speakerPhonePreference != SpeakerPhonePreference.AUTO) {
+            return;
+        }
+        // The proximity sensor should only be activated when there are exactly two
+        // available audio devices.
+        if (audioDevices.size() == 2
+                && audioDevices.contains(AppRTCAudioManager.AudioDevice.EARPIECE)
+                && audioDevices.contains(AppRTCAudioManager.AudioDevice.SPEAKER_PHONE)) {
+            if (proximitySensor.sensorReportsNearState()) {
+                // Sensor reports that a "handset is being held up to a person's ear",
+                // or "something is covering the light sensor".
+                setAudioDeviceInternal(AppRTCAudioManager.AudioDevice.EARPIECE);
+            } else {
+                // Sensor reports that a "handset is removed from a person's ear", or
+                // "the light sensor is no longer covered".
+                setAudioDeviceInternal(AppRTCAudioManager.AudioDevice.SPEAKER_PHONE);
+            }
+        }
+    }
+
+    @SuppressWarnings("deprecation")
+    public void start(AudioManagerEvents audioManagerEvents) {
+        Log.d(Config.LOGTAG, AppRTCAudioManager.class.getName() + ".start()");
+        ThreadUtils.checkIsOnMainThread();
+        if (amState == AudioManagerState.RUNNING) {
+            Log.e(Config.LOGTAG, "AudioManager is already active");
+            return;
+        }
+        awaitMicrophoneLatch();
+        this.audioManagerEvents = audioManagerEvents;
+        amState = AudioManagerState.RUNNING;
+        // Store current audio state so we can restore it when stop() is called.
+        savedIsSpeakerPhoneOn = audioManager.isSpeakerphoneOn();
+        savedIsMicrophoneMute = audioManager.isMicrophoneMute();
+        hasWiredHeadset = hasWiredHeadset();
+        // Create an AudioManager.OnAudioFocusChangeListener instance.
+        audioFocusChangeListener =
+                new AudioManager.OnAudioFocusChangeListener() {
+                    // Called on the listener to notify if the audio focus for this listener has
+                    // been changed.
+                    // The |focusChange| value indicates whether the focus was gained, whether the
+                    // focus was lost,
+                    // and whether that loss is transient, or whether the new focus holder will hold
+                    // it for an
+                    // unknown amount of time.
+                    // TODO(henrika): possibly extend support of handling audio-focus changes. Only
+                    // contains
+                    // logging for now.
+                    @Override
+                    public void onAudioFocusChange(int focusChange) {
+                        final String typeOfChange;
+                        switch (focusChange) {
+                            case AudioManager.AUDIOFOCUS_GAIN:
+                                typeOfChange = "AUDIOFOCUS_GAIN";
+                                break;
+                            case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT:
+                                typeOfChange = "AUDIOFOCUS_GAIN_TRANSIENT";
+                                break;
+                            case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE:
+                                typeOfChange = "AUDIOFOCUS_GAIN_TRANSIENT_EXCLUSIVE";
+                                break;
+                            case AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK:
+                                typeOfChange = "AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK";
+                                break;
+                            case AudioManager.AUDIOFOCUS_LOSS:
+                                typeOfChange = "AUDIOFOCUS_LOSS";
+                                break;
+                            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
+                                typeOfChange = "AUDIOFOCUS_LOSS_TRANSIENT";
+                                break;
+                            case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
+                                typeOfChange = "AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK";
+                                break;
+                            default:
+                                typeOfChange = "AUDIOFOCUS_INVALID";
+                                break;
+                        }
+                        Log.d(Config.LOGTAG, "onAudioFocusChange: " + typeOfChange);
+                    }
+                };
+        // Request audio playout focus (without ducking) and install listener for changes in focus.
+        int result =
+                audioManager.requestAudioFocus(
+                        audioFocusChangeListener,
+                        AudioManager.STREAM_VOICE_CALL,
+                        AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
+        if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
+            Log.d(Config.LOGTAG, "Audio focus request granted for VOICE_CALL streams");
+        } else {
+            Log.e(Config.LOGTAG, "Audio focus request failed");
+        }
+        // Start by setting MODE_IN_COMMUNICATION as default audio mode. It is
+        // required to be in this mode when playout and/or recording starts for
+        // best possible VoIP performance.
+        audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
+        // Always disable microphone mute during a WebRTC call.
+        setMicrophoneMute(false);
+        // Set initial device states.
+        userSelectedAudioDevice = AudioDevice.NONE;
+        selectedAudioDevice = AudioDevice.NONE;
+        audioDevices.clear();
+        // Initialize and start Bluetooth if a BT device is available or initiate
+        // detection of new (enabled) BT devices.
+        bluetoothManager.start();
+        // Do initial selection of audio device. This setting can later be changed
+        // either by adding/removing a BT or wired headset or by covering/uncovering
+        // the proximity sensor.
+        updateAudioDeviceState();
+        // Register receiver for broadcast intents related to adding/removing a
+        // wired headset.
+        registerReceiver(wiredHeadsetReceiver, new IntentFilter(Intent.ACTION_HEADSET_PLUG));
+        Log.d(Config.LOGTAG, "AudioManager started");
+    }
+
+    private void awaitMicrophoneLatch() {
+        final CountDownLatch latch = microphoneLatch;
+        if (latch == null) {
+            return;
+        }
+        try {
+            latch.await();
+        } catch (InterruptedException e) {
+            // ignore
+        }
+    }
+
+    @SuppressWarnings("deprecation")
+    public void stop() {
+        Log.d(Config.LOGTAG, AppRTCAudioManager.class.getName() + ".stop()");
+        ThreadUtils.checkIsOnMainThread();
+        if (amState != AudioManagerState.RUNNING) {
+            Log.e(Config.LOGTAG, "Trying to stop AudioManager in incorrect state: " + amState);
+            return;
+        }
+        amState = AudioManagerState.UNINITIALIZED;
+        unregisterReceiver(wiredHeadsetReceiver);
+        bluetoothManager.stop();
+        // Restore previously stored audio states.
+        setSpeakerphoneOn(savedIsSpeakerPhoneOn);
+        setMicrophoneMute(savedIsMicrophoneMute);
+        audioManager.setMode(AudioManager.MODE_NORMAL);
+        // Abandon audio focus. Gives the previous focus owner, if any, focus.
+        audioManager.abandonAudioFocus(audioFocusChangeListener);
+        audioFocusChangeListener = null;
+        Log.d(Config.LOGTAG, "Abandoned audio focus for VOICE_CALL streams");
+        if (proximitySensor != null) {
+            proximitySensor.stop();
+            proximitySensor = null;
+        }
+        audioManagerEvents = null;
+    }
+
+    /** Changes selection of the currently active audio device. */
+    private void setAudioDeviceInternal(AudioDevice device) {
+        Log.d(Config.LOGTAG, "setAudioDeviceInternal(device=" + device + ")");
+        AppRTCUtils.assertIsTrue(audioDevices.contains(device));
+        switch (device) {
+            case SPEAKER_PHONE:
+                setSpeakerphoneOn(true);
+                break;
+            case EARPIECE:
+            case WIRED_HEADSET:
+            case BLUETOOTH:
+                setSpeakerphoneOn(false);
+                break;
+            default:
+                Log.e(Config.LOGTAG, "Invalid audio device selection");
+                break;
+        }
+        selectedAudioDevice = device;
+    }
+
+    /**
+     * Changes default audio device. TODO(henrika): add usage of this method in the AppRTCMobile
+     * client.
+     */
+    public void setDefaultAudioDevice(AudioDevice defaultDevice) {
+        ThreadUtils.checkIsOnMainThread();
+        switch (defaultDevice) {
+            case SPEAKER_PHONE:
+                defaultAudioDevice = defaultDevice;
+                break;
+            case EARPIECE:
+                if (hasEarpiece()) {
+                    defaultAudioDevice = defaultDevice;
+                } else {
+                    defaultAudioDevice = AudioDevice.SPEAKER_PHONE;
+                }
+                break;
+            default:
+                Log.e(Config.LOGTAG, "Invalid default audio device selection");
+                break;
+        }
+        Log.d(Config.LOGTAG, "setDefaultAudioDevice(device=" + defaultAudioDevice + ")");
+        updateAudioDeviceState();
+    }
+
+    /** Changes selection of the currently active audio device. */
+    public void selectAudioDevice(AudioDevice device) {
+        ThreadUtils.checkIsOnMainThread();
+        if (!audioDevices.contains(device)) {
+            Log.e(Config.LOGTAG, "Can not select " + device + " from available " + audioDevices);
+        }
+        userSelectedAudioDevice = device;
+        updateAudioDeviceState();
+    }
+
+    /** Returns current set of available/selectable audio devices. */
+    public Set<AudioDevice> getAudioDevices() {
+        ThreadUtils.checkIsOnMainThread();
+        return Collections.unmodifiableSet(new HashSet<>(audioDevices));
+    }
+
+    /** Returns the currently selected audio device. */
+    public AudioDevice getSelectedAudioDevice() {
+        ThreadUtils.checkIsOnMainThread();
+        return selectedAudioDevice;
+    }
+
+    /** Helper method for receiver registration. */
+    private void registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
+        apprtcContext.registerReceiver(receiver, filter);
+    }
+
+    /** Helper method for unregistration of an existing receiver. */
+    private void unregisterReceiver(BroadcastReceiver receiver) {
+        apprtcContext.unregisterReceiver(receiver);
+    }
+
+    /** Sets the speaker phone mode. */
+    private void setSpeakerphoneOn(boolean on) {
+        boolean wasOn = audioManager.isSpeakerphoneOn();
+        if (wasOn == on) {
+            return;
+        }
+        audioManager.setSpeakerphoneOn(on);
+    }
+
+    /** Sets the microphone mute state. */
+    private void setMicrophoneMute(boolean on) {
+        boolean wasMuted = audioManager.isMicrophoneMute();
+        if (wasMuted == on) {
+            return;
+        }
+        audioManager.setMicrophoneMute(on);
+    }
+
+    /** Gets the current earpiece state. */
+    private boolean hasEarpiece() {
+        return apprtcContext.getPackageManager().hasSystemFeature(PackageManager.FEATURE_TELEPHONY);
+    }
+
+    /**
+     * Checks whether a wired headset is connected or not. This is not a valid indication that audio
+     * playback is actually over the wired headset as audio routing depends on other conditions. We
+     * only use it as an early indicator (during initialization) of an attached wired headset.
+     */
+    @Deprecated
+    private boolean hasWiredHeadset() {
+        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
+            return audioManager.isWiredHeadsetOn();
+        } else {
+            final AudioDeviceInfo[] devices = audioManager.getDevices(AudioManager.GET_DEVICES_ALL);
+            for (AudioDeviceInfo device : devices) {
+                final int type = device.getType();
+                if (type == AudioDeviceInfo.TYPE_WIRED_HEADSET) {
+                    Log.d(Config.LOGTAG, "hasWiredHeadset: found wired headset");
+                    return true;
+                } else if (type == AudioDeviceInfo.TYPE_USB_DEVICE) {
+                    Log.d(Config.LOGTAG, "hasWiredHeadset: found USB audio device");
+                    return true;
+                }
+            }
+            return false;
+        }
+    }
+
+    /**
+     * Updates list of possible audio devices and make new device selection. TODO(henrika): add unit
+     * test to verify all state transitions.
+     */
+    public void updateAudioDeviceState() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(
+                Config.LOGTAG,
+                "--- updateAudioDeviceState: "
+                        + "wired headset="
+                        + hasWiredHeadset
+                        + ", "
+                        + "BT state="
+                        + bluetoothManager.getState());
+        Log.d(
+                Config.LOGTAG,
+                "Device status: "
+                        + "available="
+                        + audioDevices
+                        + ", "
+                        + "selected="
+                        + selectedAudioDevice
+                        + ", "
+                        + "user selected="
+                        + userSelectedAudioDevice);
+        // Check if any Bluetooth headset is connected. The internal BT state will
+        // change accordingly.
+        // TODO(henrika): perhaps wrap required state into BT manager.
+        if (bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_AVAILABLE
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_UNAVAILABLE
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_DISCONNECTING) {
+            bluetoothManager.updateDevice();
+        }
+        // Update the set of available audio devices.
+        Set<AudioDevice> newAudioDevices = new HashSet<>();
+        if (bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTED
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTING
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_AVAILABLE) {
+            newAudioDevices.add(AudioDevice.BLUETOOTH);
+        }
+        if (hasWiredHeadset) {
+            // If a wired headset is connected, then it is the only possible option.
+            newAudioDevices.add(AudioDevice.WIRED_HEADSET);
+        } else {
+            // No wired headset, hence the audio-device list can contain speaker
+            // phone (on a tablet), or speaker phone and earpiece (on mobile phone).
+            newAudioDevices.add(AudioDevice.SPEAKER_PHONE);
+            if (hasEarpiece()) {
+                newAudioDevices.add(AudioDevice.EARPIECE);
+            }
+        }
+        // Store state which is set to true if the device list has changed.
+        boolean audioDeviceSetUpdated = !audioDevices.equals(newAudioDevices);
+        // Update the existing audio device set.
+        audioDevices = newAudioDevices;
+        // Correct user selected audio devices if needed.
+        if (bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_UNAVAILABLE
+                && userSelectedAudioDevice == AudioDevice.BLUETOOTH) {
+            // If BT is not available, it can't be the user selection.
+            userSelectedAudioDevice = AudioDevice.NONE;
+        }
+        if (hasWiredHeadset && userSelectedAudioDevice == AudioDevice.SPEAKER_PHONE) {
+            // If user selected speaker phone, but then plugged wired headset then make
+            // wired headset as user selected device.
+            userSelectedAudioDevice = AudioDevice.WIRED_HEADSET;
+        }
+        if (!hasWiredHeadset && userSelectedAudioDevice == AudioDevice.WIRED_HEADSET) {
+            // If user selected wired headset, but then unplugged wired headset then make
+            // speaker phone as user selected device.
+            userSelectedAudioDevice = AudioDevice.SPEAKER_PHONE;
+        }
+        // Need to start Bluetooth if it is available and user either selected it explicitly or
+        // user did not select any output device.
+        boolean needBluetoothAudioStart =
+                bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_AVAILABLE
+                        && (userSelectedAudioDevice == AudioDevice.NONE
+                                || userSelectedAudioDevice == AudioDevice.BLUETOOTH);
+        // Need to stop Bluetooth audio if user selected different device and
+        // Bluetooth SCO connection is established or in the process.
+        boolean needBluetoothAudioStop =
+                (bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTED
+                                || bluetoothManager.getState()
+                                        == AppRTCBluetoothManager.State.SCO_CONNECTING)
+                        && (userSelectedAudioDevice != AudioDevice.NONE
+                                && userSelectedAudioDevice != AudioDevice.BLUETOOTH);
+        if (bluetoothManager.getState() == AppRTCBluetoothManager.State.HEADSET_AVAILABLE
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTING
+                || bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTED) {
+            Log.d(
+                    Config.LOGTAG,
+                    "Need BT audio: start="
+                            + needBluetoothAudioStart
+                            + ", "
+                            + "stop="
+                            + needBluetoothAudioStop
+                            + ", "
+                            + "BT state="
+                            + bluetoothManager.getState());
+        }
+        // Start or stop Bluetooth SCO connection given states set earlier.
+        if (needBluetoothAudioStop) {
+            bluetoothManager.stopScoAudio();
+            bluetoothManager.updateDevice();
+        }
+        if (needBluetoothAudioStart && !needBluetoothAudioStop) {
+            // Attempt to start Bluetooth SCO audio (takes a few second to start).
+            if (!bluetoothManager.startScoAudio()) {
+                // Remove BLUETOOTH from list of available devices since SCO failed.
+                audioDevices.remove(AudioDevice.BLUETOOTH);
+                audioDeviceSetUpdated = true;
+            }
+        }
+        // Update selected audio device.
+        final AudioDevice newAudioDevice;
+        if (bluetoothManager.getState() == AppRTCBluetoothManager.State.SCO_CONNECTED) {
+            // If a Bluetooth is connected, then it should be used as output audio
+            // device. Note that it is not sufficient that a headset is available;
+            // an active SCO channel must also be up and running.
+            newAudioDevice = AudioDevice.BLUETOOTH;
+        } else if (hasWiredHeadset) {
+            // If a wired headset is connected, but Bluetooth is not, then wired headset is used as
+            // audio device.
+            newAudioDevice = AudioDevice.WIRED_HEADSET;
+        } else {
+            // No wired headset and no Bluetooth, hence the audio-device list can contain speaker
+            // phone (on a tablet), or speaker phone and earpiece (on mobile phone).
+            // |defaultAudioDevice| contains either AudioDevice.SPEAKER_PHONE or
+            // AudioDevice.EARPIECE
+            // depending on the user's selection.
+            newAudioDevice = defaultAudioDevice;
+        }
+        // Switch to new device but only if there has been any changes.
+        if (newAudioDevice != selectedAudioDevice || audioDeviceSetUpdated) {
+            // Do the required device switch.
+            setAudioDeviceInternal(newAudioDevice);
+            Log.d(
+                    Config.LOGTAG,
+                    "New device status: "
+                            + "available="
+                            + audioDevices
+                            + ", "
+                            + "selected="
+                            + newAudioDevice);
+            if (audioManagerEvents != null) {
+                // Notify a listening client that audio device has been changed.
+                audioManagerEvents.onAudioDeviceChanged(selectedAudioDevice, audioDevices);
+            }
+        }
+        Log.d(Config.LOGTAG, "--- updateAudioDeviceState done");
+    }
+
+    /** AudioDevice is the names of possible audio devices that we currently support. */
+    public enum AudioDevice {
+        SPEAKER_PHONE,
+        WIRED_HEADSET,
+        EARPIECE,
+        BLUETOOTH,
+        NONE
+    }
+
+    /** AudioManager state. */
+    public enum AudioManagerState {
+        UNINITIALIZED,
+        PREINITIALIZED,
+        RUNNING,
+    }
+
+    public enum SpeakerPhonePreference {
+        AUTO,
+        EARPIECE,
+        SPEAKER;
+
+        public static SpeakerPhonePreference of(final Set<Media> media) {
+            if (media.contains(Media.VIDEO)) {
+                return SPEAKER;
+            } else {
+                return EARPIECE;
+            }
+        }
+    }
+
+    /** Selected audio device change event. */
+    public interface AudioManagerEvents {
+        // Callback fired once audio device is changed or list of available audio devices changed.
+        void onAudioDeviceChanged(
+                AudioDevice selectedAudioDevice, Set<AudioDevice> availableAudioDevices);
+    }
+
+    /* Receiver which handles changes in wired headset availability. */
+    private class WiredHeadsetReceiver extends BroadcastReceiver {
+        private static final int STATE_UNPLUGGED = 0;
+        private static final int STATE_PLUGGED = 1;
+        private static final int HAS_NO_MIC = 0;
+        private static final int HAS_MIC = 1;
+
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            int state = intent.getIntExtra("state", STATE_UNPLUGGED);
+            int microphone = intent.getIntExtra("microphone", HAS_NO_MIC);
+            String name = intent.getStringExtra("name");
+            Log.d(
+                    Config.LOGTAG,
+                    "WiredHeadsetReceiver.onReceive"
+                            + AppRTCUtils.getThreadInfo()
+                            + ": "
+                            + "a="
+                            + intent.getAction()
+                            + ", s="
+                            + (state == STATE_UNPLUGGED ? "unplugged" : "plugged")
+                            + ", m="
+                            + (microphone == HAS_MIC ? "mic" : "no mic")
+                            + ", n="
+                            + name
+                            + ", sb="
+                            + isInitialStickyBroadcast());
+            hasWiredHeadset = (state == STATE_PLUGGED);
+            updateAudioDeviceState();
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/services/AppRTCBluetoothManager.java

@@ -0,0 +1,570 @@
+/*
+ *  Copyright 2016 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+package eu.siacs.conversations.services;
+
+import android.Manifest;
+import android.annotation.SuppressLint;
+import android.bluetooth.BluetoothAdapter;
+import android.bluetooth.BluetoothDevice;
+import android.bluetooth.BluetoothHeadset;
+import android.bluetooth.BluetoothProfile;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.content.pm.PackageManager;
+import android.media.AudioManager;
+import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
+import android.util.Log;
+import androidx.annotation.Nullable;
+import androidx.core.app.ActivityCompat;
+import com.google.common.collect.ImmutableList;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.utils.AppRTCUtils;
+import java.util.Collections;
+import java.util.List;
+import org.webrtc.ThreadUtils;
+
+/** AppRTCProximitySensor manages functions related to Bluetoth devices in the AppRTC demo. */
+public class AppRTCBluetoothManager {
+    // Timeout interval for starting or stopping audio to a Bluetooth SCO device.
+    private static final int BLUETOOTH_SCO_TIMEOUT_MS = 4000;
+    // Maximum number of SCO connection attempts.
+    private static final int MAX_SCO_CONNECTION_ATTEMPTS = 2;
+    private final Context apprtcContext;
+    private final AppRTCAudioManager apprtcAudioManager;
+    @Nullable private final AudioManager audioManager;
+    private final Handler handler;
+    private final BluetoothProfile.ServiceListener bluetoothServiceListener;
+    private final BroadcastReceiver bluetoothHeadsetReceiver;
+    int scoConnectionAttempts;
+    private State bluetoothState;
+    @Nullable private BluetoothAdapter bluetoothAdapter;
+    @Nullable private BluetoothHeadset bluetoothHeadset;
+    @Nullable private BluetoothDevice bluetoothDevice;
+    // Runs when the Bluetooth timeout expires. We use that timeout after calling
+    // startScoAudio() or stopScoAudio() because we're not guaranteed to get a
+    // callback after those calls.
+    private final Runnable bluetoothTimeoutRunnable =
+            new Runnable() {
+                @Override
+                public void run() {
+                    bluetoothTimeout();
+                }
+            };
+
+    protected AppRTCBluetoothManager(Context context, AppRTCAudioManager audioManager) {
+        Log.d(Config.LOGTAG, "ctor");
+        ThreadUtils.checkIsOnMainThread();
+        apprtcContext = context;
+        apprtcAudioManager = audioManager;
+        this.audioManager = getAudioManager(context);
+        bluetoothState = State.UNINITIALIZED;
+        bluetoothServiceListener = new BluetoothServiceListener();
+        bluetoothHeadsetReceiver = new BluetoothHeadsetBroadcastReceiver();
+        handler = new Handler(Looper.getMainLooper());
+    }
+
+    /** Construction. */
+    static AppRTCBluetoothManager create(Context context, AppRTCAudioManager audioManager) {
+        Log.d(Config.LOGTAG, "create" + AppRTCUtils.getThreadInfo());
+        return new AppRTCBluetoothManager(context, audioManager);
+    }
+
+    /** Returns the internal state. */
+    public State getState() {
+        ThreadUtils.checkIsOnMainThread();
+        return bluetoothState;
+    }
+
+    /**
+     * Activates components required to detect Bluetooth devices and to enable BT SCO (audio is
+     * routed via BT SCO) for the headset profile. The end state will be HEADSET_UNAVAILABLE but a
+     * state machine has started which will start a state change sequence where the final outcome
+     * depends on if/when the BT headset is enabled. Example of state change sequence when start()
+     * is called while BT device is connected and enabled: UNINITIALIZED --> HEADSET_UNAVAILABLE -->
+     * HEADSET_AVAILABLE --> SCO_CONNECTING --> SCO_CONNECTED <==> audio is now routed via BT SCO.
+     * Note that the AppRTCAudioManager is also involved in driving this state change.
+     */
+    public void start() {
+        ThreadUtils.checkIsOnMainThread();
+        if (bluetoothState != State.UNINITIALIZED) {
+            Log.w(Config.LOGTAG, "Invalid BT state");
+            return;
+        }
+        bluetoothHeadset = null;
+        bluetoothDevice = null;
+        scoConnectionAttempts = 0;
+        // Get a handle to the default local Bluetooth adapter.
+        bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
+        if (bluetoothAdapter == null) {
+            Log.w(Config.LOGTAG, "Device does not support Bluetooth");
+            return;
+        }
+        // Ensure that the device supports use of BT SCO audio for off call use cases.
+        if (this.audioManager == null || !audioManager.isBluetoothScoAvailableOffCall()) {
+            Log.e(Config.LOGTAG, "Bluetooth SCO audio is not available off call");
+            return;
+        }
+        // Establish a connection to the HEADSET profile (includes both Bluetooth Headset and
+        // Hands-Free) proxy object and install a listener.
+        if (!getBluetoothProfileProxy(
+                apprtcContext, bluetoothServiceListener, BluetoothProfile.HEADSET)) {
+            Log.e(Config.LOGTAG, "BluetoothAdapter.getProfileProxy(HEADSET) failed");
+            return;
+        }
+        // Register receivers for BluetoothHeadset change notifications.
+        IntentFilter bluetoothHeadsetFilter = new IntentFilter();
+        // Register receiver for change in connection state of the Headset profile.
+        bluetoothHeadsetFilter.addAction(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED);
+        // Register receiver for change in audio connection state of the Headset profile.
+        bluetoothHeadsetFilter.addAction(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED);
+        registerReceiver(bluetoothHeadsetReceiver, bluetoothHeadsetFilter);
+        if (hasBluetoothConnectPermission()) {
+            Log.d(
+                    Config.LOGTAG,
+                    "HEADSET profile state: "
+                            + stateToString(
+                                    bluetoothAdapter.getProfileConnectionState(
+                                            BluetoothProfile.HEADSET)));
+        }
+        Log.d(Config.LOGTAG, "Bluetooth proxy for headset profile has started");
+        bluetoothState = State.HEADSET_UNAVAILABLE;
+        Log.d(Config.LOGTAG, "start done: BT state=" + bluetoothState);
+    }
+
+    /** Stops and closes all components related to Bluetooth audio. */
+    public void stop() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(Config.LOGTAG, "stop: BT state=" + bluetoothState);
+        if (bluetoothAdapter == null) {
+            return;
+        }
+        // Stop BT SCO connection with remote device if needed.
+        stopScoAudio();
+        // Close down remaining BT resources.
+        if (bluetoothState == State.UNINITIALIZED) {
+            return;
+        }
+        unregisterReceiver(bluetoothHeadsetReceiver);
+        cancelTimer();
+        if (bluetoothHeadset != null) {
+            bluetoothAdapter.closeProfileProxy(BluetoothProfile.HEADSET, bluetoothHeadset);
+            bluetoothHeadset = null;
+        }
+        bluetoothAdapter = null;
+        bluetoothDevice = null;
+        bluetoothState = State.UNINITIALIZED;
+        Log.d(Config.LOGTAG, "stop done: BT state=" + bluetoothState);
+    }
+
+    /**
+     * Starts Bluetooth SCO connection with remote device. Note that the phone application always
+     * has the priority on the usage of the SCO connection for telephony. If this method is called
+     * while the phone is in call it will be ignored. Similarly, if a call is received or sent while
+     * an application is using the SCO connection, the connection will be lost for the application
+     * and NOT returned automatically when the call ends. Also note that: up to and including API
+     * version JELLY_BEAN_MR1, this method initiates a virtual voice call to the Bluetooth headset.
+     * After API version JELLY_BEAN_MR2 only a raw SCO audio connection is established.
+     * TODO(henrika): should we add support for virtual voice call to BT headset also for JBMR2 and
+     * higher. It might be required to initiates a virtual voice call since many devices do not
+     * accept SCO audio without a "call".
+     */
+    public boolean startScoAudio() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(
+                Config.LOGTAG,
+                "startSco: BT state="
+                        + bluetoothState
+                        + ", "
+                        + "attempts: "
+                        + scoConnectionAttempts
+                        + ", "
+                        + "SCO is on: "
+                        + isScoOn());
+        if (scoConnectionAttempts >= MAX_SCO_CONNECTION_ATTEMPTS) {
+            Log.e(Config.LOGTAG, "BT SCO connection fails - no more attempts");
+            return false;
+        }
+        if (bluetoothState != State.HEADSET_AVAILABLE) {
+            Log.e(Config.LOGTAG, "BT SCO connection fails - no headset available");
+            return false;
+        }
+        // Start BT SCO channel and wait for ACTION_AUDIO_STATE_CHANGED.
+        Log.d(Config.LOGTAG, "Starting Bluetooth SCO and waits for ACTION_AUDIO_STATE_CHANGED...");
+        // The SCO connection establishment can take several seconds, hence we cannot rely on the
+        // connection to be available when the method returns but instead register to receive the
+        // intent ACTION_SCO_AUDIO_STATE_UPDATED and wait for the state to be
+        // SCO_AUDIO_STATE_CONNECTED.
+        bluetoothState = State.SCO_CONNECTING;
+        audioManager.startBluetoothSco();
+        audioManager.setBluetoothScoOn(true);
+        scoConnectionAttempts++;
+        startTimer();
+        Log.d(
+                Config.LOGTAG,
+                "startScoAudio done: BT state="
+                        + bluetoothState
+                        + ", "
+                        + "SCO is on: "
+                        + isScoOn());
+        return true;
+    }
+
+    /** Stops Bluetooth SCO connection with remote device. */
+    public void stopScoAudio() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(
+                Config.LOGTAG,
+                "stopScoAudio: BT state=" + bluetoothState + ", " + "SCO is on: " + isScoOn());
+        if (bluetoothState != State.SCO_CONNECTING && bluetoothState != State.SCO_CONNECTED) {
+            return;
+        }
+        cancelTimer();
+        audioManager.stopBluetoothSco();
+        audioManager.setBluetoothScoOn(false);
+        bluetoothState = State.SCO_DISCONNECTING;
+        Log.d(
+                Config.LOGTAG,
+                "stopScoAudio done: BT state=" + bluetoothState + ", " + "SCO is on: " + isScoOn());
+    }
+
+    /**
+     * Use the BluetoothHeadset proxy object (controls the Bluetooth Headset Service via IPC) to
+     * update the list of connected devices for the HEADSET profile. The internal state will change
+     * to HEADSET_UNAVAILABLE or to HEADSET_AVAILABLE and |bluetoothDevice| will be mapped to the
+     * connected device if available.
+     */
+    @SuppressLint("MissingPermission")
+    public void updateDevice() {
+        if (bluetoothState == State.UNINITIALIZED || bluetoothHeadset == null) {
+            return;
+        }
+        Log.d(Config.LOGTAG, "updateDevice");
+        // Get connected devices for the headset profile. Returns the set of
+        // devices which are in state STATE_CONNECTED. The BluetoothDevice class
+        // is just a thin wrapper for a Bluetooth hardware address.
+        final List<BluetoothDevice> devices;
+        if (hasBluetoothConnectPermission()) {
+            devices = bluetoothHeadset.getConnectedDevices();
+        } else {
+            devices = ImmutableList.of();
+        }
+        if (devices.isEmpty()) {
+            bluetoothDevice = null;
+            bluetoothState = State.HEADSET_UNAVAILABLE;
+            Log.d(Config.LOGTAG, "No connected bluetooth headset");
+        } else {
+            // Always use first device in list. Android only supports one device.
+            bluetoothDevice = devices.get(0);
+            bluetoothState = State.HEADSET_AVAILABLE;
+            Log.d(
+                    Config.LOGTAG,
+                    "Connected bluetooth headset: "
+                            + "name="
+                            + bluetoothDevice.getName()
+                            + ", "
+                            + "state="
+                            + stateToString(bluetoothHeadset.getConnectionState(bluetoothDevice))
+                            + ", SCO audio="
+                            + bluetoothHeadset.isAudioConnected(bluetoothDevice));
+        }
+        Log.d(Config.LOGTAG, "updateDevice done: BT state=" + bluetoothState);
+    }
+
+    /** Stubs for test mocks. */
+    @Nullable
+    protected AudioManager getAudioManager(Context context) {
+        return (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+    }
+
+    protected void registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
+        apprtcContext.registerReceiver(receiver, filter);
+    }
+
+    protected void unregisterReceiver(BroadcastReceiver receiver) {
+        apprtcContext.unregisterReceiver(receiver);
+    }
+
+    protected boolean getBluetoothProfileProxy(
+            Context context, BluetoothProfile.ServiceListener listener, int profile) {
+        return bluetoothAdapter.getProfileProxy(context, listener, profile);
+    }
+
+    protected boolean hasBluetoothConnectPermission() {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+            return ActivityCompat.checkSelfPermission(
+                            apprtcContext, Manifest.permission.BLUETOOTH_CONNECT)
+                    == PackageManager.PERMISSION_GRANTED;
+        } else {
+            return true;
+        }
+    }
+
+    /** Ensures that the audio manager updates its list of available audio devices. */
+    private void updateAudioDeviceState() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(Config.LOGTAG, "updateAudioDeviceState");
+        apprtcAudioManager.updateAudioDeviceState();
+    }
+
+    /** Starts timer which times out after BLUETOOTH_SCO_TIMEOUT_MS milliseconds. */
+    private void startTimer() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(Config.LOGTAG, "startTimer");
+        handler.postDelayed(bluetoothTimeoutRunnable, BLUETOOTH_SCO_TIMEOUT_MS);
+    }
+
+    /** Cancels any outstanding timer tasks. */
+    private void cancelTimer() {
+        ThreadUtils.checkIsOnMainThread();
+        Log.d(Config.LOGTAG, "cancelTimer");
+        handler.removeCallbacks(bluetoothTimeoutRunnable);
+    }
+
+    /**
+     * Called when start of the BT SCO channel takes too long time. Usually happens when the BT
+     * device has been turned on during an ongoing call.
+     */
+    @SuppressLint("MissingPermission")
+    private void bluetoothTimeout() {
+        ThreadUtils.checkIsOnMainThread();
+        if (bluetoothState == State.UNINITIALIZED || bluetoothHeadset == null) {
+            return;
+        }
+        Log.d(
+                Config.LOGTAG,
+                "bluetoothTimeout: BT state="
+                        + bluetoothState
+                        + ", "
+                        + "attempts: "
+                        + scoConnectionAttempts
+                        + ", "
+                        + "SCO is on: "
+                        + isScoOn());
+        if (bluetoothState != State.SCO_CONNECTING) {
+            return;
+        }
+        // Bluetooth SCO should be connecting; check the latest result.
+        boolean scoConnected = false;
+        final List<BluetoothDevice> devices;
+        if (hasBluetoothConnectPermission()) {
+            devices = bluetoothHeadset.getConnectedDevices();
+        } else {
+            devices = Collections.emptyList();
+        }
+        if (devices.size() > 0) {
+            bluetoothDevice = devices.get(0);
+            if (bluetoothHeadset.isAudioConnected(bluetoothDevice)) {
+                Log.d(Config.LOGTAG, "SCO connected with " + bluetoothDevice.getName());
+                scoConnected = true;
+            } else {
+                Log.d(Config.LOGTAG, "SCO is not connected with " + bluetoothDevice.getName());
+            }
+        }
+        if (scoConnected) {
+            // We thought BT had timed out, but it's actually on; updating state.
+            bluetoothState = State.SCO_CONNECTED;
+            scoConnectionAttempts = 0;
+        } else {
+            // Give up and "cancel" our request by calling stopBluetoothSco().
+            Log.w(Config.LOGTAG, "BT failed to connect after timeout");
+            stopScoAudio();
+        }
+        updateAudioDeviceState();
+        Log.d(Config.LOGTAG, "bluetoothTimeout done: BT state=" + bluetoothState);
+    }
+
+    /** Checks whether audio uses Bluetooth SCO. */
+    private boolean isScoOn() {
+        return audioManager.isBluetoothScoOn();
+    }
+
+    /** Converts BluetoothAdapter states into local string representations. */
+    private String stateToString(int state) {
+        switch (state) {
+            case BluetoothAdapter.STATE_DISCONNECTED:
+                return "DISCONNECTED";
+            case BluetoothAdapter.STATE_CONNECTED:
+                return "CONNECTED";
+            case BluetoothAdapter.STATE_CONNECTING:
+                return "CONNECTING";
+            case BluetoothAdapter.STATE_DISCONNECTING:
+                return "DISCONNECTING";
+            case BluetoothAdapter.STATE_OFF:
+                return "OFF";
+            case BluetoothAdapter.STATE_ON:
+                return "ON";
+            case BluetoothAdapter.STATE_TURNING_OFF:
+                // Indicates the local Bluetooth adapter is turning off. Local clients should
+                // immediately
+                // attempt graceful disconnection of any remote links.
+                return "TURNING_OFF";
+            case BluetoothAdapter.STATE_TURNING_ON:
+                // Indicates the local Bluetooth adapter is turning on. However local clients should
+                // wait
+                // for STATE_ON before attempting to use the adapter.
+                return "TURNING_ON";
+            default:
+                return "INVALID";
+        }
+    }
+
+    // Bluetooth connection state.
+    public enum State {
+        // Bluetooth is not available; no adapter or Bluetooth is off.
+        UNINITIALIZED,
+        // Bluetooth error happened when trying to start Bluetooth.
+        ERROR,
+        // Bluetooth proxy object for the Headset profile exists, but no connected headset devices,
+        // SCO is not started or disconnected.
+        HEADSET_UNAVAILABLE,
+        // Bluetooth proxy object for the Headset profile connected, connected Bluetooth headset
+        // present, but SCO is not started or disconnected.
+        HEADSET_AVAILABLE,
+        // Bluetooth audio SCO connection with remote device is closing.
+        SCO_DISCONNECTING,
+        // Bluetooth audio SCO connection with remote device is initiated.
+        SCO_CONNECTING,
+        // Bluetooth audio SCO connection with remote device is established.
+        SCO_CONNECTED
+    }
+
+    /**
+     * Implementation of an interface that notifies BluetoothProfile IPC clients when they have been
+     * connected to or disconnected from the service.
+     */
+    private class BluetoothServiceListener implements BluetoothProfile.ServiceListener {
+        @Override
+        // Called to notify the client when the proxy object has been connected to the service.
+        // Once we have the profile proxy object, we can use it to monitor the state of the
+        // connection and perform other operations that are relevant to the headset profile.
+        public void onServiceConnected(int profile, BluetoothProfile proxy) {
+            if (profile != BluetoothProfile.HEADSET || bluetoothState == State.UNINITIALIZED) {
+                return;
+            }
+            Log.d(
+                    Config.LOGTAG,
+                    "BluetoothServiceListener.onServiceConnected: BT state=" + bluetoothState);
+            // Android only supports one connected Bluetooth Headset at a time.
+            bluetoothHeadset = (BluetoothHeadset) proxy;
+            updateAudioDeviceState();
+            Log.d(Config.LOGTAG, "onServiceConnected done: BT state=" + bluetoothState);
+        }
+
+        @Override
+        /** Notifies the client when the proxy object has been disconnected from the service. */
+        public void onServiceDisconnected(int profile) {
+            if (profile != BluetoothProfile.HEADSET || bluetoothState == State.UNINITIALIZED) {
+                return;
+            }
+            Log.d(
+                    Config.LOGTAG,
+                    "BluetoothServiceListener.onServiceDisconnected: BT state=" + bluetoothState);
+            stopScoAudio();
+            bluetoothHeadset = null;
+            bluetoothDevice = null;
+            bluetoothState = State.HEADSET_UNAVAILABLE;
+            updateAudioDeviceState();
+            Log.d(Config.LOGTAG, "onServiceDisconnected done: BT state=" + bluetoothState);
+        }
+    }
+
+    // Intent broadcast receiver which handles changes in Bluetooth device availability.
+    // Detects headset changes and Bluetooth SCO state changes.
+    private class BluetoothHeadsetBroadcastReceiver extends BroadcastReceiver {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (bluetoothState == State.UNINITIALIZED) {
+                return;
+            }
+            final String action = intent.getAction();
+            // Change in connection state of the Headset profile. Note that the
+            // change does not tell us anything about whether we're streaming
+            // audio to BT over SCO. Typically received when user turns on a BT
+            // headset while audio is active using another audio device.
+            if (action.equals(BluetoothHeadset.ACTION_CONNECTION_STATE_CHANGED)) {
+                final int state =
+                        intent.getIntExtra(
+                                BluetoothHeadset.EXTRA_STATE, BluetoothHeadset.STATE_DISCONNECTED);
+                Log.d(
+                        Config.LOGTAG,
+                        "BluetoothHeadsetBroadcastReceiver.onReceive: "
+                                + "a=ACTION_CONNECTION_STATE_CHANGED, "
+                                + "s="
+                                + stateToString(state)
+                                + ", "
+                                + "sb="
+                                + isInitialStickyBroadcast()
+                                + ", "
+                                + "BT state: "
+                                + bluetoothState);
+                if (state == BluetoothHeadset.STATE_CONNECTED) {
+                    scoConnectionAttempts = 0;
+                    updateAudioDeviceState();
+                } else if (state == BluetoothHeadset.STATE_CONNECTING) {
+                    // No action needed.
+                } else if (state == BluetoothHeadset.STATE_DISCONNECTING) {
+                    // No action needed.
+                } else if (state == BluetoothHeadset.STATE_DISCONNECTED) {
+                    // Bluetooth is probably powered off during the call.
+                    stopScoAudio();
+                    updateAudioDeviceState();
+                }
+                // Change in the audio (SCO) connection state of the Headset profile.
+                // Typically received after call to startScoAudio() has finalized.
+            } else if (action.equals(BluetoothHeadset.ACTION_AUDIO_STATE_CHANGED)) {
+                final int state =
+                        intent.getIntExtra(
+                                BluetoothHeadset.EXTRA_STATE,
+                                BluetoothHeadset.STATE_AUDIO_DISCONNECTED);
+                Log.d(
+                        Config.LOGTAG,
+                        "BluetoothHeadsetBroadcastReceiver.onReceive: "
+                                + "a=ACTION_AUDIO_STATE_CHANGED, "
+                                + "s="
+                                + stateToString(state)
+                                + ", "
+                                + "sb="
+                                + isInitialStickyBroadcast()
+                                + ", "
+                                + "BT state: "
+                                + bluetoothState);
+                if (state == BluetoothHeadset.STATE_AUDIO_CONNECTED) {
+                    cancelTimer();
+                    if (bluetoothState == State.SCO_CONNECTING) {
+                        Log.d(Config.LOGTAG, "+++ Bluetooth audio SCO is now connected");
+                        bluetoothState = State.SCO_CONNECTED;
+                        scoConnectionAttempts = 0;
+                        updateAudioDeviceState();
+                    } else {
+                        Log.w(
+                                Config.LOGTAG,
+                                "Unexpected state BluetoothHeadset.STATE_AUDIO_CONNECTED");
+                    }
+                } else if (state == BluetoothHeadset.STATE_AUDIO_CONNECTING) {
+                    Log.d(Config.LOGTAG, "+++ Bluetooth audio SCO is now connecting...");
+                } else if (state == BluetoothHeadset.STATE_AUDIO_DISCONNECTED) {
+                    Log.d(Config.LOGTAG, "+++ Bluetooth audio SCO is now disconnected");
+                    if (isInitialStickyBroadcast()) {
+                        Log.d(
+                                Config.LOGTAG,
+                                "Ignore STATE_AUDIO_DISCONNECTED initial sticky broadcast.");
+                        return;
+                    }
+                    updateAudioDeviceState();
+                }
+            }
+            Log.d(Config.LOGTAG, "onReceive done: BT state=" + bluetoothState);
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/services/AppRTCProximitySensor.java

@@ -0,0 +1,161 @@
+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+package eu.siacs.conversations.services;
+
+import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import android.os.Build;
+import android.util.Log;
+import androidx.annotation.Nullable;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.utils.AppRTCUtils;
+import org.webrtc.ThreadUtils;
+
+/**
+ * AppRTCProximitySensor manages functions related to the proximity sensor in the AppRTC demo. On
+ * most device, the proximity sensor is implemented as a boolean-sensor. It returns just two values
+ * "NEAR" or "FAR". Thresholding is done on the LUX value i.e. the LUX value of the light sensor is
+ * compared with a threshold. A LUX-value more than the threshold means the proximity sensor returns
+ * "FAR". Anything less than the threshold value and the sensor returns "NEAR".
+ */
+public class AppRTCProximitySensor implements SensorEventListener {
+    // This class should be created, started and stopped on one thread
+    // (e.g. the main thread). We use |nonThreadSafe| to ensure that this is
+    // the case. Only active when |DEBUG| is set to true.
+    private final ThreadUtils.ThreadChecker threadChecker = new ThreadUtils.ThreadChecker();
+    private final Runnable onSensorStateListener;
+    private final SensorManager sensorManager;
+    @Nullable private Sensor proximitySensor;
+    private boolean lastStateReportIsNear;
+
+    private AppRTCProximitySensor(Context context, Runnable sensorStateListener) {
+        Log.d(Config.LOGTAG, "AppRTCProximitySensor" + AppRTCUtils.getThreadInfo());
+        onSensorStateListener = sensorStateListener;
+        sensorManager = ((SensorManager) context.getSystemService(Context.SENSOR_SERVICE));
+    }
+
+    /** Construction */
+    static AppRTCProximitySensor create(Context context, Runnable sensorStateListener) {
+        return new AppRTCProximitySensor(context, sensorStateListener);
+    }
+
+    /** Activate the proximity sensor. Also do initialization if called for the first time. */
+    public boolean start() {
+        threadChecker.checkIsOnValidThread();
+        Log.d(Config.LOGTAG, "start" + AppRTCUtils.getThreadInfo());
+        if (!initDefaultSensor()) {
+            // Proximity sensor is not supported on this device.
+            return false;
+        }
+        sensorManager.registerListener(this, proximitySensor, SensorManager.SENSOR_DELAY_NORMAL);
+        return true;
+    }
+
+    /** Deactivate the proximity sensor. */
+    public void stop() {
+        threadChecker.checkIsOnValidThread();
+        Log.d(Config.LOGTAG, "stop" + AppRTCUtils.getThreadInfo());
+        if (proximitySensor == null) {
+            return;
+        }
+        sensorManager.unregisterListener(this, proximitySensor);
+    }
+
+    /** Getter for last reported state. Set to true if "near" is reported. */
+    public boolean sensorReportsNearState() {
+        threadChecker.checkIsOnValidThread();
+        return lastStateReportIsNear;
+    }
+
+    @Override
+    public final void onAccuracyChanged(Sensor sensor, int accuracy) {
+        threadChecker.checkIsOnValidThread();
+        AppRTCUtils.assertIsTrue(sensor.getType() == Sensor.TYPE_PROXIMITY);
+        if (accuracy == SensorManager.SENSOR_STATUS_UNRELIABLE) {
+            Log.e(Config.LOGTAG, "The values returned by this sensor cannot be trusted");
+        }
+    }
+
+    @Override
+    public final void onSensorChanged(SensorEvent event) {
+        threadChecker.checkIsOnValidThread();
+        AppRTCUtils.assertIsTrue(event.sensor.getType() == Sensor.TYPE_PROXIMITY);
+        // As a best practice; do as little as possible within this method and
+        // avoid blocking.
+        float distanceInCentimeters = event.values[0];
+        if (distanceInCentimeters < proximitySensor.getMaximumRange()) {
+            Log.d(Config.LOGTAG, "Proximity sensor => NEAR state");
+            lastStateReportIsNear = true;
+        } else {
+            Log.d(Config.LOGTAG, "Proximity sensor => FAR state");
+            lastStateReportIsNear = false;
+        }
+        // Report about new state to listening client. Client can then call
+        // sensorReportsNearState() to query the current state (NEAR or FAR).
+        if (onSensorStateListener != null) {
+            onSensorStateListener.run();
+        }
+        Log.d(
+                Config.LOGTAG,
+                "onSensorChanged"
+                        + AppRTCUtils.getThreadInfo()
+                        + ": "
+                        + "accuracy="
+                        + event.accuracy
+                        + ", timestamp="
+                        + event.timestamp
+                        + ", distance="
+                        + event.values[0]);
+    }
+
+    /**
+     * Get default proximity sensor if it exists. Tablet devices (e.g. Nexus 7) does not support
+     * this type of sensor and false will be returned in such cases.
+     */
+    private boolean initDefaultSensor() {
+        if (proximitySensor != null) {
+            return true;
+        }
+        proximitySensor = sensorManager.getDefaultSensor(Sensor.TYPE_PROXIMITY);
+        if (proximitySensor == null) {
+            return false;
+        }
+        logProximitySensorInfo();
+        return true;
+    }
+
+    /** Helper method for logging information about the proximity sensor. */
+    private void logProximitySensorInfo() {
+        if (proximitySensor == null) {
+            return;
+        }
+        StringBuilder info = new StringBuilder("Proximity sensor: ");
+        info.append("name=").append(proximitySensor.getName());
+        info.append(", vendor: ").append(proximitySensor.getVendor());
+        info.append(", power: ").append(proximitySensor.getPower());
+        info.append(", resolution: ").append(proximitySensor.getResolution());
+        info.append(", max range: ").append(proximitySensor.getMaximumRange());
+        info.append(", min delay: ").append(proximitySensor.getMinDelay());
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT_WATCH) {
+            // Added in API level 20.
+            info.append(", type: ").append(proximitySensor.getStringType());
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+            // Added in API level 21.
+            info.append(", max delay: ").append(proximitySensor.getMaxDelay());
+            info.append(", reporting mode: ").append(proximitySensor.getReportingMode());
+            info.append(", isWakeUpSensor: ").append(proximitySensor.isWakeUpSensor());
+        }
+        Log.d(Config.LOGTAG, info.toString());
+    }
+}

app/src/main/java/eu/siacs/conversations/utils/AppRTCUtils.java

@@ -0,0 +1,66 @@
+/*
+ *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+package eu.siacs.conversations.utils;
+
+import android.os.Build;
+import android.util.Log;
+
+/** AppRTCUtils provides helper functions for managing thread safety. */
+public final class AppRTCUtils {
+    private AppRTCUtils() {}
+
+    /** Helper method which throws an exception when an assertion has failed. */
+    public static void assertIsTrue(boolean condition) {
+        if (!condition) {
+            throw new AssertionError("Expected condition to be true");
+        }
+    }
+
+    /** Helper method for building a string of thread information. */
+    public static String getThreadInfo() {
+        return "@[name="
+                + Thread.currentThread().getName()
+                + ", id="
+                + Thread.currentThread().getId()
+                + "]";
+    }
+
+    /** Information about the current build, taken from system properties. */
+    public static void logDeviceInfo(String tag) {
+        Log.d(
+                tag,
+                "Android SDK: "
+                        + Build.VERSION.SDK_INT
+                        + ", "
+                        + "Release: "
+                        + Build.VERSION.RELEASE
+                        + ", "
+                        + "Brand: "
+                        + Build.BRAND
+                        + ", "
+                        + "Device: "
+                        + Build.DEVICE
+                        + ", "
+                        + "Id: "
+                        + Build.ID
+                        + ", "
+                        + "Hardware: "
+                        + Build.HARDWARE
+                        + ", "
+                        + "Manufacturer: "
+                        + Build.MANUFACTURER
+                        + ", "
+                        + "Model: "
+                        + Build.MODEL
+                        + ", "
+                        + "Product: "
+                        + Build.PRODUCT);
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/AbstractJingleConnection.java

@@ -0,0 +1,110 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.content.Context;
+import com.google.common.base.Objects;
+import com.google.common.base.Preconditions;
+import eu.siacs.conversations.xmpp.jingle.stanzas.JinglePacket;
+import im.conversations.android.IDs;
+import im.conversations.android.xmpp.XmppConnection;
+import im.conversations.android.xmpp.model.stanza.Iq;
+import org.jxmpp.jid.Jid;
+
+public abstract class AbstractJingleConnection extends XmppConnection.Delegate {
+
+    public static final String JINGLE_MESSAGE_PROPOSE_ID_PREFIX = "jm-propose-";
+    public static final String JINGLE_MESSAGE_PROCEED_ID_PREFIX = "jm-proceed-";
+
+    protected final Id id;
+    private final Jid initiator;
+
+    AbstractJingleConnection(
+            final Context context,
+            final XmppConnection connection,
+            final Id id,
+            final Jid initiator) {
+        super(context, connection);
+        this.id = id;
+        this.initiator = initiator;
+    }
+
+    boolean isInitiator() {
+        return initiator.equals(connection.getBoundAddress());
+    }
+
+    public abstract void deliverPacket(Iq jinglePacket);
+
+    public Id getId() {
+        return id;
+    }
+
+    public abstract void notifyRebound();
+
+    public static class Id implements OngoingRtpSession {
+        public final Jid with;
+        public final String sessionId;
+
+        private Id(final Jid with, final String sessionId) {
+            Preconditions.checkNotNull(with);
+            Preconditions.checkNotNull(sessionId);
+            this.with = with;
+            this.sessionId = sessionId;
+        }
+
+        public static Id of(final JinglePacket jinglePacket) {
+            return new Id(jinglePacket.getFrom(), jinglePacket.getSessionId());
+        }
+
+        public static Id of(Jid with, final String sessionId) {
+            return new Id(with, sessionId);
+        }
+
+        public static Id of(Jid with) {
+            return new Id(with, IDs.medium());
+        }
+
+        @Override
+        public Jid getWith() {
+            return with;
+        }
+
+        @Override
+        public String getSessionId() {
+            return sessionId;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Id id = (Id) o;
+            return Objects.equal(with, id.with) && Objects.equal(sessionId, id.sessionId);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(with, sessionId);
+        }
+    }
+
+    public enum State {
+        NULL, // default value; nothing has been sent or received yet
+        PROPOSED,
+        ACCEPTED,
+        PROCEED,
+        REJECTED,
+        REJECTED_RACED, // used when we want to reject but haven’t received session init yet
+        RETRACTED,
+        RETRACTED_RACED, // used when receiving a retract after we already asked to proceed
+        SESSION_INITIALIZED, // equal to 'PENDING'
+        SESSION_INITIALIZED_PRE_APPROVED,
+        SESSION_ACCEPTED, // equal to 'ACTIVE'
+        TERMINATED_SUCCESS, // equal to 'ENDED' (after successful call) ui will just close
+        TERMINATED_DECLINED_OR_BUSY, // equal to 'ENDED' (after other party declined the call)
+        TERMINATED_CONNECTIVITY_ERROR, // equal to 'ENDED' (but after network failures; ui will
+        // display retry button)
+        TERMINATED_CANCEL_OR_TIMEOUT, // more or less the same as retracted; caller pressed end call
+        // before session was accepted
+        TERMINATED_APPLICATION_FAILURE,
+        TERMINATED_SECURITY_ERROR
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/ContentAddition.java

@@ -0,0 +1,86 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Objects;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableSet;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Content;
+import java.util.Set;
+
+public final class ContentAddition {
+
+    public final Direction direction;
+    public final Set<Summary> summary;
+
+    private ContentAddition(Direction direction, Set<Summary> summary) {
+        this.direction = direction;
+        this.summary = summary;
+    }
+
+    public Set<Media> media() {
+        return ImmutableSet.copyOf(Collections2.transform(summary, s -> s.media));
+    }
+
+    public static ContentAddition of(final Direction direction, final RtpContentMap rtpContentMap) {
+        return new ContentAddition(direction, summary(rtpContentMap));
+    }
+
+    public static Set<Summary> summary(final RtpContentMap rtpContentMap) {
+        return ImmutableSet.copyOf(
+                Collections2.transform(
+                        rtpContentMap.contents.entrySet(),
+                        e -> {
+                            final RtpContentMap.DescriptionTransport dt = e.getValue();
+                            return new Summary(e.getKey(), dt.description.getMedia(), dt.senders);
+                        }));
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("direction", direction)
+                .add("summary", summary)
+                .toString();
+    }
+
+    public enum Direction {
+        OUTGOING,
+        INCOMING
+    }
+
+    public static final class Summary {
+        public final String name;
+        public final Media media;
+        public final Content.Senders senders;
+
+        private Summary(final String name, final Media media, final Content.Senders senders) {
+            this.name = name;
+            this.media = media;
+            this.senders = senders;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Summary summary = (Summary) o;
+            return Objects.equal(name, summary.name)
+                    && media == summary.media
+                    && senders == summary.senders;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(name, media, senders);
+        }
+
+        @Override
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                    .add("name", name)
+                    .add("media", media)
+                    .add("senders", senders)
+                    .toString();
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/DirectConnectionUtils.java

@@ -0,0 +1,64 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.NetworkInterface;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+import java.security.SecureRandom;
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.List;
+import java.util.UUID;
+import org.jxmpp.jid.Jid;
+
+public class DirectConnectionUtils {
+
+    private static List<InetAddress> getLocalAddresses() {
+        final List<InetAddress> addresses = new ArrayList<>();
+        final Enumeration<NetworkInterface> interfaces;
+        try {
+            interfaces = NetworkInterface.getNetworkInterfaces();
+        } catch (SocketException e) {
+            return addresses;
+        }
+        while (interfaces.hasMoreElements()) {
+            NetworkInterface networkInterface = interfaces.nextElement();
+            final Enumeration<InetAddress> inetAddressEnumeration =
+                    networkInterface.getInetAddresses();
+            while (inetAddressEnumeration.hasMoreElements()) {
+                final InetAddress inetAddress = inetAddressEnumeration.nextElement();
+                if (inetAddress.isLoopbackAddress() || inetAddress.isLinkLocalAddress()) {
+                    continue;
+                }
+                if (inetAddress instanceof Inet6Address) {
+                    // let's get rid of scope
+                    try {
+                        addresses.add(Inet6Address.getByAddress(inetAddress.getAddress()));
+                    } catch (UnknownHostException e) {
+                        // ignored
+                    }
+                } else {
+                    addresses.add(inetAddress);
+                }
+            }
+        }
+        return addresses;
+    }
+
+    public static List<JingleCandidate> getLocalCandidates(Jid jid) {
+        SecureRandom random = new SecureRandom();
+        ArrayList<JingleCandidate> candidates = new ArrayList<>();
+        for (InetAddress inetAddress : getLocalAddresses()) {
+            final JingleCandidate candidate =
+                    new JingleCandidate(UUID.randomUUID().toString(), true);
+            candidate.setHost(inetAddress.getHostAddress());
+            candidate.setPort(random.nextInt(60000) + 1024);
+            candidate.setType(JingleCandidate.TYPE_DIRECT);
+            candidate.setJid(jid);
+            candidate.setPriority(8257536 + candidates.size());
+            candidates.add(candidate);
+        }
+        return candidates;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/JingleCandidate.java

@@ -0,0 +1,153 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import im.conversations.android.xml.Element;
+import java.util.ArrayList;
+import java.util.List;
+import org.jxmpp.jid.Jid;
+
+public class JingleCandidate {
+
+    public static int TYPE_UNKNOWN;
+    public static int TYPE_DIRECT = 0;
+    public static int TYPE_PROXY = 1;
+
+    private final boolean ours;
+    private boolean usedByCounterpart = false;
+    private final String cid;
+    private String host;
+    private int port;
+    private int type;
+    private Jid jid;
+    private int priority;
+
+    public JingleCandidate(String cid, boolean ours) {
+        this.ours = ours;
+        this.cid = cid;
+    }
+
+    public String getCid() {
+        return cid;
+    }
+
+    public void setHost(String host) {
+        this.host = host;
+    }
+
+    public String getHost() {
+        return this.host;
+    }
+
+    public void setJid(final Jid jid) {
+        this.jid = jid;
+    }
+
+    public Jid getJid() {
+        return this.jid;
+    }
+
+    public void setPort(int port) {
+        this.port = port;
+    }
+
+    public int getPort() {
+        return this.port;
+    }
+
+    public void setType(int type) {
+        this.type = type;
+    }
+
+    public void setType(String type) {
+        if (type == null) {
+            this.type = TYPE_UNKNOWN;
+            return;
+        }
+        switch (type) {
+            case "proxy":
+                this.type = TYPE_PROXY;
+                break;
+            case "direct":
+                this.type = TYPE_DIRECT;
+                break;
+            default:
+                this.type = TYPE_UNKNOWN;
+                break;
+        }
+    }
+
+    public void setPriority(int i) {
+        this.priority = i;
+    }
+
+    public int getPriority() {
+        return this.priority;
+    }
+
+    public boolean equals(JingleCandidate other) {
+        return this.getCid().equals(other.getCid());
+    }
+
+    public boolean equalValues(JingleCandidate other) {
+        return other != null
+                && other.getHost().equals(this.getHost())
+                && (other.getPort() == this.getPort());
+    }
+
+    public boolean isOurs() {
+        return ours;
+    }
+
+    public int getType() {
+        return this.type;
+    }
+
+    public static List<JingleCandidate> parse(final List<Element> elements) {
+        final List<JingleCandidate> candidates = new ArrayList<>();
+        for (final Element element : elements) {
+            if ("candidate".equals(element.getName())) {
+                candidates.add(JingleCandidate.parse(element));
+            }
+        }
+        return candidates;
+    }
+
+    public static JingleCandidate parse(Element element) {
+        final JingleCandidate candidate = new JingleCandidate(element.getAttribute("cid"), false);
+        candidate.setHost(element.getAttribute("host"));
+        candidate.setJid(element.getAttributeAsJid("jid"));
+        candidate.setType(element.getAttribute("type"));
+        candidate.setPriority(Integer.parseInt(element.getAttribute("priority")));
+        candidate.setPort(Integer.parseInt(element.getAttribute("port")));
+        return candidate;
+    }
+
+    public Element toElement() {
+        Element element = new Element("candidate");
+        element.setAttribute("cid", this.getCid());
+        element.setAttribute("host", this.getHost());
+        element.setAttribute("port", Integer.toString(this.getPort()));
+        if (jid != null) {
+            element.setAttribute("jid", jid);
+        }
+        element.setAttribute("priority", Integer.toString(this.getPriority()));
+        if (this.getType() == TYPE_DIRECT) {
+            element.setAttribute("type", "direct");
+        } else if (this.getType() == TYPE_PROXY) {
+            element.setAttribute("type", "proxy");
+        }
+        return element;
+    }
+
+    public void flagAsUsedByCounterpart() {
+        this.usedByCounterpart = true;
+    }
+
+    public boolean isUsedByCounterpart() {
+        return this.usedByCounterpart;
+    }
+
+    public String toString() {
+        return String.format(
+                "%s:%s (priority=%s,ours=%s)", getHost(), getPort(), getPriority(), isOurs());
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/Media.java

@@ -0,0 +1,34 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.collect.ImmutableSet;
+import java.util.Locale;
+import java.util.Set;
+import javax.annotation.Nonnull;
+
+public enum Media {
+    VIDEO,
+    AUDIO,
+    UNKNOWN;
+
+    @Override
+    @Nonnull
+    public String toString() {
+        return super.toString().toLowerCase(Locale.ROOT);
+    }
+
+    public static Media of(String value) {
+        try {
+            return value == null ? UNKNOWN : Media.valueOf(value.toUpperCase(Locale.ROOT));
+        } catch (IllegalArgumentException e) {
+            return UNKNOWN;
+        }
+    }
+
+    public static boolean audioOnly(Set<Media> media) {
+        return ImmutableSet.of(AUDIO).equals(media);
+    }
+
+    public static boolean videoOnly(Set<Media> media) {
+        return ImmutableSet.of(VIDEO).equals(media);
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/MediaBuilder.java

@@ -0,0 +1,48 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.collect.ArrayListMultimap;
+import java.util.List;
+
+public class MediaBuilder {
+    private String media;
+    private int port;
+    private String protocol;
+    private List<Integer> formats;
+    private String connectionData;
+    private ArrayListMultimap<String, String> attributes;
+
+    public MediaBuilder setMedia(String media) {
+        this.media = media;
+        return this;
+    }
+
+    public MediaBuilder setPort(int port) {
+        this.port = port;
+        return this;
+    }
+
+    public MediaBuilder setProtocol(String protocol) {
+        this.protocol = protocol;
+        return this;
+    }
+
+    public MediaBuilder setFormats(List<Integer> formats) {
+        this.formats = formats;
+        return this;
+    }
+
+    public MediaBuilder setConnectionData(String connectionData) {
+        this.connectionData = connectionData;
+        return this;
+    }
+
+    public MediaBuilder setAttributes(ArrayListMultimap<String, String> attributes) {
+        this.attributes = attributes;
+        return this;
+    }
+
+    public SessionDescription.Media createMedia() {
+        return new SessionDescription.Media(
+                media, port, protocol, formats, connectionData, attributes);
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/OmemoVerification.java

@@ -0,0 +1,83 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Preconditions;
+import im.conversations.android.axolotl.AxolotlService;
+import java.util.concurrent.atomic.AtomicBoolean;
+import org.whispersystems.libsignal.IdentityKey;
+
+public class OmemoVerification {
+
+    private final AtomicBoolean deviceIdWritten = new AtomicBoolean(false);
+    private final AtomicBoolean identityKeyWritten = new AtomicBoolean(false);
+    private Integer deviceId;
+    private IdentityKey identityKey;
+
+    public void setDeviceId(final Integer id) {
+        if (deviceIdWritten.compareAndSet(false, true)) {
+            this.deviceId = id;
+            return;
+        }
+        throw new IllegalStateException("Device Id has already been set");
+    }
+
+    public int getDeviceId() {
+        Preconditions.checkNotNull(this.deviceId, "Device ID is null");
+        return this.deviceId;
+    }
+
+    public boolean hasDeviceId() {
+        return this.deviceId != null;
+    }
+
+    public void setSessionFingerprint(final IdentityKey identityKey) {
+        Preconditions.checkNotNull(identityKey, "IdentityKey must not be null");
+        if (identityKeyWritten.compareAndSet(false, true)) {
+            this.identityKey = identityKey;
+            return;
+        }
+        throw new IllegalStateException("Identity Key has already been set");
+    }
+
+    public IdentityKey getFingerprint() {
+        return this.identityKey;
+    }
+
+    public void setOrEnsureEqual(AxolotlService.OmemoVerifiedPayload<?> omemoVerifiedPayload) {
+        setOrEnsureEqual(omemoVerifiedPayload.getDeviceId(), omemoVerifiedPayload.getFingerprint());
+    }
+
+    public void setOrEnsureEqual(final int deviceId, final IdentityKey identityKey) {
+        Preconditions.checkNotNull(identityKey, "IdentityKey must not be null");
+        if (this.deviceIdWritten.get() || this.identityKeyWritten.get()) {
+            if (this.identityKey == null) {
+                throw new IllegalStateException(
+                        "No session fingerprint has been previously provided");
+            }
+            if (!identityKey.equals(this.identityKey)) {
+                throw new SecurityException("IdentityKeys did not match");
+            }
+            if (this.deviceId == null) {
+                throw new IllegalStateException("No Device Id has been previously provided");
+            }
+            if (this.deviceId != deviceId) {
+                throw new IllegalStateException("Device Ids did not match");
+            }
+        } else {
+            this.setSessionFingerprint(identityKey);
+            this.setDeviceId(deviceId);
+        }
+    }
+
+    public boolean hasFingerprint() {
+        return this.identityKey != null;
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(this)
+                .add("deviceId", deviceId)
+                .add("fingerprint", identityKey)
+                .toString();
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/OmemoVerifiedRtpContentMap.java

@@ -0,0 +1,20 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import eu.siacs.conversations.xmpp.jingle.stanzas.Group;
+import eu.siacs.conversations.xmpp.jingle.stanzas.OmemoVerifiedIceUdpTransportInfo;
+import java.util.Map;
+
+public class OmemoVerifiedRtpContentMap extends RtpContentMap {
+    public OmemoVerifiedRtpContentMap(Group group, Map<String, DescriptionTransport> contents) {
+        super(group, contents);
+        for (final DescriptionTransport descriptionTransport : contents.values()) {
+            if (descriptionTransport.transport instanceof OmemoVerifiedIceUdpTransportInfo) {
+                ((OmemoVerifiedIceUdpTransportInfo) descriptionTransport.transport)
+                        .ensureNoPlaintextFingerprint();
+                continue;
+            }
+            throw new IllegalStateException(
+                    "OmemoVerifiedRtpContentMap contains non-verified transport info");
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/OnPrimaryCandidateFound.java

@@ -0,0 +1,5 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+public interface OnPrimaryCandidateFound {
+    void onPrimaryCandidateFound(boolean success, JingleCandidate canditate);
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/OnTransportConnected.java

@@ -0,0 +1,7 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+public interface OnTransportConnected {
+    void failed();
+
+    void established();
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/OngoingRtpSession.java

@@ -0,0 +1,9 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import org.jxmpp.jid.Jid;
+
+public interface OngoingRtpSession {
+    Jid getWith();
+
+    String getSessionId();
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/RtpContentMap.java

@@ -0,0 +1,489 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Objects;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Predicates;
+import com.google.common.base.Strings;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Maps;
+import com.google.common.collect.Sets;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Content;
+import eu.siacs.conversations.xmpp.jingle.stanzas.GenericDescription;
+import eu.siacs.conversations.xmpp.jingle.stanzas.GenericTransportInfo;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Group;
+import eu.siacs.conversations.xmpp.jingle.stanzas.IceUdpTransportInfo;
+import eu.siacs.conversations.xmpp.jingle.stanzas.JinglePacket;
+import eu.siacs.conversations.xmpp.jingle.stanzas.OmemoVerifiedIceUdpTransportInfo;
+import eu.siacs.conversations.xmpp.jingle.stanzas.RtpDescription;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import javax.annotation.Nonnull;
+
+public class RtpContentMap {
+
+    public final Group group;
+    public final Map<String, DescriptionTransport> contents;
+
+    public RtpContentMap(Group group, Map<String, DescriptionTransport> contents) {
+        this.group = group;
+        this.contents = contents;
+    }
+
+    public static RtpContentMap of(final JinglePacket jinglePacket) {
+        final Map<String, DescriptionTransport> contents =
+                DescriptionTransport.of(jinglePacket.getJingleContents());
+        if (isOmemoVerified(contents)) {
+            return new OmemoVerifiedRtpContentMap(jinglePacket.getGroup(), contents);
+        } else {
+            return new RtpContentMap(jinglePacket.getGroup(), contents);
+        }
+    }
+
+    private static boolean isOmemoVerified(Map<String, DescriptionTransport> contents) {
+        final Collection<DescriptionTransport> values = contents.values();
+        if (values.size() == 0) {
+            return false;
+        }
+        for (final DescriptionTransport descriptionTransport : values) {
+            if (descriptionTransport.transport instanceof OmemoVerifiedIceUdpTransportInfo) {
+                continue;
+            }
+            return false;
+        }
+        return true;
+    }
+
+    public static RtpContentMap of(
+            final SessionDescription sessionDescription, final boolean isInitiator) {
+        final ImmutableMap.Builder<String, DescriptionTransport> contentMapBuilder =
+                new ImmutableMap.Builder<>();
+        for (SessionDescription.Media media : sessionDescription.media) {
+            final String id = Iterables.getFirst(media.attributes.get("mid"), null);
+            Preconditions.checkNotNull(id, "media has no mid");
+            contentMapBuilder.put(
+                    id, DescriptionTransport.of(sessionDescription, isInitiator, media));
+        }
+        final String groupAttribute =
+                Iterables.getFirst(sessionDescription.attributes.get("group"), null);
+        final Group group = groupAttribute == null ? null : Group.ofSdpString(groupAttribute);
+        return new RtpContentMap(group, contentMapBuilder.build());
+    }
+
+    public Set<Media> getMedia() {
+        return Sets.newHashSet(
+                Collections2.transform(
+                        contents.values(),
+                        input -> {
+                            final RtpDescription rtpDescription =
+                                    input == null ? null : input.description;
+                            return rtpDescription == null
+                                    ? Media.UNKNOWN
+                                    : input.description.getMedia();
+                        }));
+    }
+
+    public Set<Content.Senders> getSenders() {
+        return ImmutableSet.copyOf(Collections2.transform(contents.values(), dt -> dt.senders));
+    }
+
+    public List<String> getNames() {
+        return ImmutableList.copyOf(contents.keySet());
+    }
+
+    void requireContentDescriptions() {
+        if (this.contents.size() == 0) {
+            throw new IllegalStateException("No contents available");
+        }
+        for (Map.Entry<String, DescriptionTransport> entry : this.contents.entrySet()) {
+            if (entry.getValue().description == null) {
+                throw new IllegalStateException(
+                        String.format("%s is lacking content description", entry.getKey()));
+            }
+        }
+    }
+
+    void requireDTLSFingerprint() {
+        requireDTLSFingerprint(false);
+    }
+
+    void requireDTLSFingerprint(final boolean requireActPass) {
+        if (this.contents.size() == 0) {
+            throw new IllegalStateException("No contents available");
+        }
+        for (Map.Entry<String, DescriptionTransport> entry : this.contents.entrySet()) {
+            final IceUdpTransportInfo transport = entry.getValue().transport;
+            final IceUdpTransportInfo.Fingerprint fingerprint = transport.getFingerprint();
+            if (fingerprint == null
+                    || Strings.isNullOrEmpty(fingerprint.getContent())
+                    || Strings.isNullOrEmpty(fingerprint.getHash())) {
+                throw new SecurityException(
+                        String.format(
+                                "Use of DTLS-SRTP (XEP-0320) is required for content %s",
+                                entry.getKey()));
+            }
+            final IceUdpTransportInfo.Setup setup = fingerprint.getSetup();
+            if (setup == null) {
+                throw new SecurityException(
+                        String.format(
+                                "Use of DTLS-SRTP (XEP-0320) is required for content %s but"
+                                        + " missing setup attribute",
+                                entry.getKey()));
+            }
+            if (requireActPass && setup != IceUdpTransportInfo.Setup.ACTPASS) {
+                throw new SecurityException(
+                        "Initiator needs to offer ACTPASS as setup for DTLS-SRTP (XEP-0320)");
+            }
+        }
+    }
+
+    JinglePacket toJinglePacket(final JinglePacket.Action action, final String sessionId) {
+        final JinglePacket jinglePacket = new JinglePacket(action, sessionId);
+        if (this.group != null) {
+            jinglePacket.addGroup(this.group);
+        }
+        for (Map.Entry<String, DescriptionTransport> entry : this.contents.entrySet()) {
+            final DescriptionTransport descriptionTransport = entry.getValue();
+            final Content content =
+                    new Content(
+                            Content.Creator.INITIATOR,
+                            descriptionTransport.senders,
+                            entry.getKey());
+            if (descriptionTransport.description != null) {
+                content.addChild(descriptionTransport.description);
+            }
+            content.addChild(descriptionTransport.transport);
+            jinglePacket.addJingleContent(content);
+        }
+        return jinglePacket;
+    }
+
+    RtpContentMap transportInfo(
+            final String contentName, final IceUdpTransportInfo.Candidate candidate) {
+        final RtpContentMap.DescriptionTransport descriptionTransport = contents.get(contentName);
+        final IceUdpTransportInfo transportInfo =
+                descriptionTransport == null ? null : descriptionTransport.transport;
+        if (transportInfo == null) {
+            throw new IllegalArgumentException(
+                    "Unable to find transport info for content name " + contentName);
+        }
+        final IceUdpTransportInfo newTransportInfo = transportInfo.cloneWrapper();
+        newTransportInfo.addChild(candidate);
+        return new RtpContentMap(
+                null,
+                ImmutableMap.of(
+                        contentName,
+                        new DescriptionTransport(
+                                descriptionTransport.senders, null, newTransportInfo)));
+    }
+
+    RtpContentMap transportInfo() {
+        return new RtpContentMap(
+                null,
+                Maps.transformValues(
+                        contents,
+                        dt ->
+                                new DescriptionTransport(
+                                        dt.senders, null, dt.transport.cloneWrapper())));
+    }
+
+    public IceUdpTransportInfo.Credentials getDistinctCredentials() {
+        final Set<IceUdpTransportInfo.Credentials> allCredentials = getCredentials();
+        final IceUdpTransportInfo.Credentials credentials =
+                Iterables.getFirst(allCredentials, null);
+        if (allCredentials.size() == 1 && credentials != null) {
+            if (Strings.isNullOrEmpty(credentials.password)
+                    || Strings.isNullOrEmpty(credentials.ufrag)) {
+                throw new IllegalStateException("Credentials are missing password or ufrag");
+            }
+            return credentials;
+        }
+        throw new IllegalStateException("Content map does not have distinct credentials");
+    }
+
+    public Set<IceUdpTransportInfo.Credentials> getCredentials() {
+        final Set<IceUdpTransportInfo.Credentials> credentials =
+                ImmutableSet.copyOf(
+                        Collections2.transform(
+                                contents.values(), dt -> dt.transport.getCredentials()));
+        if (credentials.isEmpty()) {
+            throw new IllegalStateException("Content map does not have any credentials");
+        }
+        return credentials;
+    }
+
+    public IceUdpTransportInfo.Credentials getCredentials(final String contentName) {
+        final DescriptionTransport descriptionTransport = this.contents.get(contentName);
+        if (descriptionTransport == null) {
+            throw new IllegalArgumentException(
+                    String.format(
+                            "Unable to find transport info for content name %s", contentName));
+        }
+        return descriptionTransport.transport.getCredentials();
+    }
+
+    public IceUdpTransportInfo.Setup getDtlsSetup() {
+        final Set<IceUdpTransportInfo.Setup> setups =
+                ImmutableSet.copyOf(
+                        Collections2.transform(
+                                contents.values(), dt -> dt.transport.getFingerprint().getSetup()));
+        final IceUdpTransportInfo.Setup setup = Iterables.getFirst(setups, null);
+        if (setups.size() == 1 && setup != null) {
+            return setup;
+        }
+        throw new IllegalStateException("Content map doesn't have distinct DTLS setup");
+    }
+
+    private DTLS getDistinctDtls() {
+        final Set<DTLS> dtlsSet =
+                ImmutableSet.copyOf(
+                        Collections2.transform(
+                                contents.values(),
+                                dt -> {
+                                    final IceUdpTransportInfo.Fingerprint fp =
+                                            dt.transport.getFingerprint();
+                                    return new DTLS(fp.getHash(), fp.getSetup(), fp.getContent());
+                                }));
+        final DTLS dtls = Iterables.getFirst(dtlsSet, null);
+        if (dtlsSet.size() == 1 && dtls != null) {
+            return dtls;
+        }
+        throw new IllegalStateException("Content map doesn't have distinct DTLS setup");
+    }
+
+    public boolean emptyCandidates() {
+        int count = 0;
+        for (DescriptionTransport descriptionTransport : contents.values()) {
+            count += descriptionTransport.transport.getCandidates().size();
+        }
+        return count == 0;
+    }
+
+    public RtpContentMap modifiedCredentials(
+            IceUdpTransportInfo.Credentials credentials, final IceUdpTransportInfo.Setup setup) {
+        final ImmutableMap.Builder<String, DescriptionTransport> contentMapBuilder =
+                new ImmutableMap.Builder<>();
+        for (final Map.Entry<String, DescriptionTransport> content : contents.entrySet()) {
+            final DescriptionTransport descriptionTransport = content.getValue();
+            final RtpDescription rtpDescription = descriptionTransport.description;
+            final IceUdpTransportInfo transportInfo = descriptionTransport.transport;
+            final IceUdpTransportInfo modifiedTransportInfo =
+                    transportInfo.modifyCredentials(credentials, setup);
+            contentMapBuilder.put(
+                    content.getKey(),
+                    new DescriptionTransport(
+                            descriptionTransport.senders, rtpDescription, modifiedTransportInfo));
+        }
+        return new RtpContentMap(this.group, contentMapBuilder.build());
+    }
+
+    public RtpContentMap modifiedSenders(final Content.Senders senders) {
+        return new RtpContentMap(
+                this.group,
+                Maps.transformValues(
+                        contents,
+                        dt -> new DescriptionTransport(senders, dt.description, dt.transport)));
+    }
+
+    public RtpContentMap toContentModification(final Collection<String> modifications) {
+        return new RtpContentMap(
+                this.group,
+                Maps.transformValues(
+                        Maps.filterKeys(contents, Predicates.in(modifications)),
+                        dt ->
+                                new DescriptionTransport(
+                                        dt.senders, dt.description, IceUdpTransportInfo.STUB)));
+    }
+
+    public RtpContentMap toStub() {
+        return new RtpContentMap(
+                null,
+                Maps.transformValues(
+                        this.contents,
+                        dt ->
+                                new DescriptionTransport(
+                                        dt.senders,
+                                        RtpDescription.stub(dt.description.getMedia()),
+                                        IceUdpTransportInfo.STUB)));
+    }
+
+    public RtpContentMap activeContents() {
+        return new RtpContentMap(
+                group, Maps.filterValues(this.contents, dt -> dt.senders != Content.Senders.NONE));
+    }
+
+    public Diff diff(final RtpContentMap rtpContentMap) {
+        final Set<String> existingContentIds = this.contents.keySet();
+        final Set<String> newContentIds = rtpContentMap.contents.keySet();
+        return new Diff(
+                ImmutableSet.copyOf(Sets.difference(newContentIds, existingContentIds)),
+                ImmutableSet.copyOf(Sets.difference(existingContentIds, newContentIds)));
+    }
+
+    public boolean iceRestart(final RtpContentMap rtpContentMap) {
+        try {
+            return !getDistinctCredentials().equals(rtpContentMap.getDistinctCredentials());
+        } catch (final IllegalStateException e) {
+            return false;
+        }
+    }
+
+    public RtpContentMap addContent(
+            final RtpContentMap modification, final IceUdpTransportInfo.Setup setup) {
+        final IceUdpTransportInfo.Credentials credentials = getDistinctCredentials();
+        final DTLS dtls = getDistinctDtls();
+        final IceUdpTransportInfo iceUdpTransportInfo =
+                IceUdpTransportInfo.of(credentials, setup, dtls.hash, dtls.fingerprint);
+        final Map<String, DescriptionTransport> combined = merge(contents, modification.contents);
+        /*new ImmutableMap.Builder<String, DescriptionTransport>()
+        .putAll(contents)
+        .putAll(modification.contents)
+        .build();*/
+        final Map<String, DescriptionTransport> combinedFixedTransport =
+                Maps.transformValues(
+                        combined,
+                        dt ->
+                                new DescriptionTransport(
+                                        dt.senders, dt.description, iceUdpTransportInfo));
+        return new RtpContentMap(modification.group, combinedFixedTransport);
+    }
+
+    private static Map<String, DescriptionTransport> merge(
+            final Map<String, DescriptionTransport> a, final Map<String, DescriptionTransport> b) {
+        final Map<String, DescriptionTransport> combined = new HashMap<>();
+        combined.putAll(a);
+        combined.putAll(b);
+        return ImmutableMap.copyOf(combined);
+    }
+
+    public static class DescriptionTransport {
+        public final Content.Senders senders;
+        public final RtpDescription description;
+        public final IceUdpTransportInfo transport;
+
+        public DescriptionTransport(
+                final Content.Senders senders,
+                final RtpDescription description,
+                final IceUdpTransportInfo transport) {
+            this.senders = senders;
+            this.description = description;
+            this.transport = transport;
+        }
+
+        public static DescriptionTransport of(final Content content) {
+            final GenericDescription description = content.getDescription();
+            final GenericTransportInfo transportInfo = content.getTransport();
+            final Content.Senders senders = content.getSenders();
+            final RtpDescription rtpDescription;
+            final IceUdpTransportInfo iceUdpTransportInfo;
+            if (description == null) {
+                rtpDescription = null;
+            } else if (description instanceof RtpDescription) {
+                rtpDescription = (RtpDescription) description;
+            } else {
+                throw new UnsupportedApplicationException(
+                        "Content does not contain rtp description");
+            }
+            if (transportInfo instanceof IceUdpTransportInfo) {
+                iceUdpTransportInfo = (IceUdpTransportInfo) transportInfo;
+            } else {
+                throw new UnsupportedTransportException(
+                        "Content does not contain ICE-UDP transport");
+            }
+            return new DescriptionTransport(
+                    senders,
+                    rtpDescription,
+                    OmemoVerifiedIceUdpTransportInfo.upgrade(iceUdpTransportInfo));
+        }
+
+        private static DescriptionTransport of(
+                final SessionDescription sessionDescription,
+                final boolean isInitiator,
+                final SessionDescription.Media media) {
+            final Content.Senders senders = Content.Senders.of(media, isInitiator);
+            final RtpDescription rtpDescription = RtpDescription.of(sessionDescription, media);
+            final IceUdpTransportInfo transportInfo =
+                    IceUdpTransportInfo.of(sessionDescription, media);
+            return new DescriptionTransport(senders, rtpDescription, transportInfo);
+        }
+
+        public static Map<String, DescriptionTransport> of(final Map<String, Content> contents) {
+            return ImmutableMap.copyOf(
+                    Maps.transformValues(
+                            contents, content -> content == null ? null : of(content)));
+        }
+    }
+
+    public static class UnsupportedApplicationException extends IllegalArgumentException {
+        UnsupportedApplicationException(String message) {
+            super(message);
+        }
+    }
+
+    public static class UnsupportedTransportException extends IllegalArgumentException {
+        UnsupportedTransportException(String message) {
+            super(message);
+        }
+    }
+
+    public static final class Diff {
+        public final Set<String> added;
+        public final Set<String> removed;
+
+        private Diff(final Set<String> added, final Set<String> removed) {
+            this.added = added;
+            this.removed = removed;
+        }
+
+        public boolean hasModifications() {
+            return !this.added.isEmpty() || !this.removed.isEmpty();
+        }
+
+        public boolean isEmpty() {
+            return this.added.isEmpty() && this.removed.isEmpty();
+        }
+
+        @Override
+        @Nonnull
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                    .add("added", added)
+                    .add("removed", removed)
+                    .toString();
+        }
+    }
+
+    public static final class DTLS {
+        public final String hash;
+        public final IceUdpTransportInfo.Setup setup;
+        public final String fingerprint;
+
+        private DTLS(String hash, IceUdpTransportInfo.Setup setup, String fingerprint) {
+            this.hash = hash;
+            this.setup = setup;
+            this.fingerprint = fingerprint;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            DTLS dtls = (DTLS) o;
+            return Objects.equal(hash, dtls.hash)
+                    && setup == dtls.setup
+                    && Objects.equal(fingerprint, dtls.fingerprint);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(hash, setup, fingerprint);
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/RtpEndUserState.java

@@ -0,0 +1,21 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+public enum RtpEndUserState {
+    INCOMING_CALL, // received a 'propose' message
+    CONNECTING, // session-initiate or session-accepted but no webrtc peer connection yet
+    CONNECTED, // session-accepted and webrtc peer connection is connected
+    RECONNECTING, // session-accepted and webrtc peer connection was connected once but is currently
+    // disconnected or failed
+    INCOMING_CONTENT_ADD, // session-accepted with a pending, incoming content-add
+    FINDING_DEVICE, // 'propose' has been sent out; no 184 ack yet
+    RINGING, // 'propose' has been sent out and it has been 184 acked
+    ACCEPTING_CALL, // 'proceed' message has been sent; but no session-initiate has been received
+    ENDING_CALL, // libwebrt says 'closed' but session-terminate hasnt gone through
+    ENDED, // close UI
+    DECLINED_OR_BUSY, // other party declined; no retry button
+    CONNECTIVITY_ERROR, // network error; retry button
+    CONNECTIVITY_LOST_ERROR, // network error but for call duration > 0
+    RETRACTED, // user pressed home or power button during 'ringing' - shows retry button
+    APPLICATION_ERROR, // something rather bad happened; libwebrtc failed or we got in IQ-error
+    SECURITY_ERROR // problem with DTLS (missing) or verification
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/SessionDescription.java

@@ -0,0 +1,415 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.util.Log;
+import android.util.Pair;
+import androidx.annotation.NonNull;
+import com.google.common.base.CharMatcher;
+import com.google.common.base.Joiner;
+import com.google.common.base.Strings;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.ImmutableList;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Group;
+import eu.siacs.conversations.xmpp.jingle.stanzas.IceUdpTransportInfo;
+import eu.siacs.conversations.xmpp.jingle.stanzas.RtpDescription;
+import im.conversations.android.xml.Namespace;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+
+public class SessionDescription {
+
+    public static final String LINE_DIVIDER = "\r\n";
+    private static final String HARDCODED_MEDIA_PROTOCOL =
+            "UDP/TLS/RTP/SAVPF"; // probably only true for DTLS-SRTP aka when we have a fingerprint
+    private static final int HARDCODED_MEDIA_PORT = 9;
+    private static final String HARDCODED_ICE_OPTIONS = "trickle";
+    private static final String HARDCODED_CONNECTION = "IN IP4 0.0.0.0";
+
+    public final int version;
+    public final String name;
+    public final String connectionData;
+    public final ArrayListMultimap<String, String> attributes;
+    public final List<Media> media;
+
+    public SessionDescription(
+            int version,
+            String name,
+            String connectionData,
+            ArrayListMultimap<String, String> attributes,
+            List<Media> media) {
+        this.version = version;
+        this.name = name;
+        this.connectionData = connectionData;
+        this.attributes = attributes;
+        this.media = media;
+    }
+
+    private static void appendAttributes(
+            StringBuilder s, ArrayListMultimap<String, String> attributes) {
+        for (Map.Entry<String, String> attribute : attributes.entries()) {
+            final String key = attribute.getKey();
+            final String value = attribute.getValue();
+            s.append("a=").append(key);
+            if (!Strings.isNullOrEmpty(value)) {
+                s.append(':').append(value);
+            }
+            s.append(LINE_DIVIDER);
+        }
+    }
+
+    public static SessionDescription parse(final String input) {
+        final SessionDescriptionBuilder sessionDescriptionBuilder = new SessionDescriptionBuilder();
+        MediaBuilder currentMediaBuilder = null;
+        ArrayListMultimap<String, String> attributeMap = ArrayListMultimap.create();
+        ImmutableList.Builder<Media> mediaBuilder = new ImmutableList.Builder<>();
+        for (final String line : input.split(LINE_DIVIDER)) {
+            final String[] pair = line.trim().split("=", 2);
+            if (pair.length < 2 || pair[0].length() != 1) {
+                Log.d(Config.LOGTAG, "skipping sdp parsing on line " + line);
+                continue;
+            }
+            final char key = pair[0].charAt(0);
+            final String value = pair[1];
+            switch (key) {
+                case 'v':
+                    sessionDescriptionBuilder.setVersion(ignorantIntParser(value));
+                    break;
+                case 'c':
+                    if (currentMediaBuilder != null) {
+                        currentMediaBuilder.setConnectionData(value);
+                    } else {
+                        sessionDescriptionBuilder.setConnectionData(value);
+                    }
+                    break;
+                case 's':
+                    sessionDescriptionBuilder.setName(value);
+                    break;
+                case 'a':
+                    final Pair<String, String> attribute = parseAttribute(value);
+                    attributeMap.put(attribute.first, attribute.second);
+                    break;
+                case 'm':
+                    if (currentMediaBuilder == null) {
+                        sessionDescriptionBuilder.setAttributes(attributeMap);
+                    } else {
+                        currentMediaBuilder.setAttributes(attributeMap);
+                        mediaBuilder.add(currentMediaBuilder.createMedia());
+                    }
+                    attributeMap = ArrayListMultimap.create();
+                    currentMediaBuilder = new MediaBuilder();
+                    final String[] parts = value.split(" ");
+                    if (parts.length >= 3) {
+                        currentMediaBuilder.setMedia(parts[0]);
+                        currentMediaBuilder.setPort(ignorantIntParser(parts[1]));
+                        currentMediaBuilder.setProtocol(parts[2]);
+                        ImmutableList.Builder<Integer> formats = new ImmutableList.Builder<>();
+                        for (int i = 3; i < parts.length; ++i) {
+                            formats.add(ignorantIntParser(parts[i]));
+                        }
+                        currentMediaBuilder.setFormats(formats.build());
+                    } else {
+                        Log.d(Config.LOGTAG, "skipping media line " + line);
+                    }
+                    break;
+            }
+        }
+        if (currentMediaBuilder != null) {
+            currentMediaBuilder.setAttributes(attributeMap);
+            mediaBuilder.add(currentMediaBuilder.createMedia());
+        } else {
+            sessionDescriptionBuilder.setAttributes(attributeMap);
+        }
+        sessionDescriptionBuilder.setMedia(mediaBuilder.build());
+        return sessionDescriptionBuilder.createSessionDescription();
+    }
+
+    public static SessionDescription of(
+            final RtpContentMap contentMap, final boolean isInitiatorContentMap) {
+        final SessionDescriptionBuilder sessionDescriptionBuilder = new SessionDescriptionBuilder();
+        final ArrayListMultimap<String, String> attributeMap = ArrayListMultimap.create();
+        final ImmutableList.Builder<Media> mediaListBuilder = new ImmutableList.Builder<>();
+        final Group group = contentMap.group;
+        if (group != null) {
+            final String semantics = group.getSemantics();
+            checkNoWhitespace(semantics, "group semantics value must not contain any whitespace");
+            attributeMap.put(
+                    "group",
+                    group.getSemantics()
+                            + " "
+                            + Joiner.on(' ').join(group.getIdentificationTags()));
+        }
+
+        attributeMap.put("msid-semantic", " WMS my-media-stream");
+
+        for (final Map.Entry<String, RtpContentMap.DescriptionTransport> entry :
+                contentMap.contents.entrySet()) {
+            final String name = entry.getKey();
+            RtpContentMap.DescriptionTransport descriptionTransport = entry.getValue();
+            RtpDescription description = descriptionTransport.description;
+            IceUdpTransportInfo transport = descriptionTransport.transport;
+            final ArrayListMultimap<String, String> mediaAttributes = ArrayListMultimap.create();
+            final String ufrag = transport.getAttribute("ufrag");
+            final String pwd = transport.getAttribute("pwd");
+            if (Strings.isNullOrEmpty(ufrag)) {
+                throw new IllegalArgumentException(
+                        "Transport element is missing required ufrag attribute");
+            }
+            checkNoWhitespace(ufrag, "ufrag value must not contain any whitespaces");
+            mediaAttributes.put("ice-ufrag", ufrag);
+            if (Strings.isNullOrEmpty(pwd)) {
+                throw new IllegalArgumentException(
+                        "Transport element is missing required pwd attribute");
+            }
+            checkNoWhitespace(pwd, "pwd value must not contain any whitespaces");
+            mediaAttributes.put("ice-pwd", pwd);
+            mediaAttributes.put("ice-options", HARDCODED_ICE_OPTIONS);
+            final IceUdpTransportInfo.Fingerprint fingerprint = transport.getFingerprint();
+            if (fingerprint != null) {
+                mediaAttributes.put(
+                        "fingerprint", fingerprint.getHash() + " " + fingerprint.getContent());
+                final IceUdpTransportInfo.Setup setup = fingerprint.getSetup();
+                if (setup != null) {
+                    mediaAttributes.put("setup", setup.toString().toLowerCase(Locale.ROOT));
+                }
+            }
+            final ImmutableList.Builder<Integer> formatBuilder = new ImmutableList.Builder<>();
+            for (RtpDescription.PayloadType payloadType : description.getPayloadTypes()) {
+                final String id = payloadType.getId();
+                if (Strings.isNullOrEmpty(id)) {
+                    throw new IllegalArgumentException("Payload type is missing id");
+                }
+                if (!isInt(id)) {
+                    throw new IllegalArgumentException("Payload id is not numeric");
+                }
+                formatBuilder.add(payloadType.getIntId());
+                mediaAttributes.put("rtpmap", payloadType.toSdpAttribute());
+                final List<RtpDescription.Parameter> parameters = payloadType.getParameters();
+                if (parameters.size() == 1) {
+                    mediaAttributes.put(
+                            "fmtp", RtpDescription.Parameter.toSdpString(id, parameters.get(0)));
+                } else if (parameters.size() > 0) {
+                    mediaAttributes.put(
+                            "fmtp", RtpDescription.Parameter.toSdpString(id, parameters));
+                }
+                for (RtpDescription.FeedbackNegotiation feedbackNegotiation :
+                        payloadType.getFeedbackNegotiations()) {
+                    final String type = feedbackNegotiation.getType();
+                    final String subtype = feedbackNegotiation.getSubType();
+                    if (Strings.isNullOrEmpty(type)) {
+                        throw new IllegalArgumentException(
+                                "a feedback for payload-type "
+                                        + id
+                                        + " negotiation is missing type");
+                    }
+                    checkNoWhitespace(
+                            type, "feedback negotiation type must not contain whitespace");
+                    mediaAttributes.put(
+                            "rtcp-fb",
+                            id
+                                    + " "
+                                    + type
+                                    + (Strings.isNullOrEmpty(subtype) ? "" : " " + subtype));
+                }
+                for (RtpDescription.FeedbackNegotiationTrrInt feedbackNegotiationTrrInt :
+                        payloadType.feedbackNegotiationTrrInts()) {
+                    mediaAttributes.put(
+                            "rtcp-fb", id + " trr-int " + feedbackNegotiationTrrInt.getValue());
+                }
+            }
+
+            for (RtpDescription.FeedbackNegotiation feedbackNegotiation :
+                    description.getFeedbackNegotiations()) {
+                final String type = feedbackNegotiation.getType();
+                final String subtype = feedbackNegotiation.getSubType();
+                if (Strings.isNullOrEmpty(type)) {
+                    throw new IllegalArgumentException("a feedback negotiation is missing type");
+                }
+                checkNoWhitespace(type, "feedback negotiation type must not contain whitespace");
+                mediaAttributes.put(
+                        "rtcp-fb",
+                        "* " + type + (Strings.isNullOrEmpty(subtype) ? "" : " " + subtype));
+            }
+            for (final RtpDescription.FeedbackNegotiationTrrInt feedbackNegotiationTrrInt :
+                    description.feedbackNegotiationTrrInts()) {
+                mediaAttributes.put("rtcp-fb", "* trr-int " + feedbackNegotiationTrrInt.getValue());
+            }
+            for (final RtpDescription.RtpHeaderExtension extension :
+                    description.getHeaderExtensions()) {
+                final String id = extension.getId();
+                final String uri = extension.getUri();
+                if (Strings.isNullOrEmpty(id)) {
+                    throw new IllegalArgumentException("A header extension is missing id");
+                }
+                checkNoWhitespace(id, "header extension id must not contain whitespace");
+                if (Strings.isNullOrEmpty(uri)) {
+                    throw new IllegalArgumentException("A header extension is missing uri");
+                }
+                checkNoWhitespace(uri, "feedback negotiation uri must not contain whitespace");
+                mediaAttributes.put("extmap", id + " " + uri);
+            }
+
+            if (description.hasChild(
+                    "extmap-allow-mixed", Namespace.JINGLE_RTP_HEADER_EXTENSIONS)) {
+                mediaAttributes.put("extmap-allow-mixed", "");
+            }
+
+            for (final RtpDescription.SourceGroup sourceGroup : description.getSourceGroups()) {
+                final String semantics = sourceGroup.getSemantics();
+                final List<String> groups = sourceGroup.getSsrcs();
+                if (Strings.isNullOrEmpty(semantics)) {
+                    throw new IllegalArgumentException(
+                            "A SSRC group is missing semantics attribute");
+                }
+                checkNoWhitespace(semantics, "source group semantics must not contain whitespace");
+                if (groups.size() == 0) {
+                    throw new IllegalArgumentException("A SSRC group is missing SSRC ids");
+                }
+                mediaAttributes.put(
+                        "ssrc-group",
+                        String.format("%s %s", semantics, Joiner.on(' ').join(groups)));
+            }
+            for (final RtpDescription.Source source : description.getSources()) {
+                for (final RtpDescription.Source.Parameter parameter : source.getParameters()) {
+                    final String id = source.getSsrcId();
+                    final String parameterName = parameter.getParameterName();
+                    final String parameterValue = parameter.getParameterValue();
+                    if (Strings.isNullOrEmpty(id)) {
+                        throw new IllegalArgumentException(
+                                "A source specific media attribute is missing the id");
+                    }
+                    checkNoWhitespace(
+                            id, "A source specific media attributes must not contain whitespaces");
+                    if (Strings.isNullOrEmpty(parameterName)) {
+                        throw new IllegalArgumentException(
+                                "A source specific media attribute is missing its name");
+                    }
+                    if (Strings.isNullOrEmpty(parameterValue)) {
+                        throw new IllegalArgumentException(
+                                "A source specific media attribute is missing its value");
+                    }
+                    mediaAttributes.put("ssrc", id + " " + parameterName + ":" + parameterValue);
+                }
+            }
+
+            mediaAttributes.put("mid", name);
+
+            mediaAttributes.put(
+                    descriptionTransport.senders.asMediaAttribute(isInitiatorContentMap), "");
+            if (description.hasChild("rtcp-mux", Namespace.JINGLE_APPS_RTP) || group != null) {
+                mediaAttributes.put("rtcp-mux", "");
+            }
+
+            // random additional attributes
+            mediaAttributes.put("rtcp", "9 IN IP4 0.0.0.0");
+
+            final MediaBuilder mediaBuilder = new MediaBuilder();
+            mediaBuilder.setMedia(description.getMedia().toString().toLowerCase(Locale.ROOT));
+            mediaBuilder.setConnectionData(HARDCODED_CONNECTION);
+            mediaBuilder.setPort(HARDCODED_MEDIA_PORT);
+            mediaBuilder.setProtocol(HARDCODED_MEDIA_PROTOCOL);
+            mediaBuilder.setAttributes(mediaAttributes);
+            mediaBuilder.setFormats(formatBuilder.build());
+            mediaListBuilder.add(mediaBuilder.createMedia());
+        }
+        sessionDescriptionBuilder.setVersion(0);
+        sessionDescriptionBuilder.setName("-");
+        sessionDescriptionBuilder.setMedia(mediaListBuilder.build());
+        sessionDescriptionBuilder.setAttributes(attributeMap);
+
+        return sessionDescriptionBuilder.createSessionDescription();
+    }
+
+    public static String checkNoWhitespace(final String input, final String message) {
+        if (CharMatcher.whitespace().matchesAnyOf(input)) {
+            throw new IllegalArgumentException(message);
+        }
+        return input;
+    }
+
+    public static int ignorantIntParser(final String input) {
+        try {
+            return Integer.parseInt(input);
+        } catch (NumberFormatException e) {
+            return 0;
+        }
+    }
+
+    public static boolean isInt(final String input) {
+        if (input == null) {
+            return false;
+        }
+        try {
+            Integer.parseInt(input);
+            return true;
+        } catch (NumberFormatException e) {
+            return false;
+        }
+    }
+
+    public static Pair<String, String> parseAttribute(final String input) {
+        final String[] pair = input.split(":", 2);
+        if (pair.length == 2) {
+            return new Pair<>(pair[0], pair[1]);
+        } else {
+            return new Pair<>(pair[0], "");
+        }
+    }
+
+    @NonNull
+    @Override
+    public String toString() {
+        final StringBuilder s =
+                new StringBuilder()
+                        .append("v=")
+                        .append(version)
+                        .append(LINE_DIVIDER)
+                        // TODO randomize or static
+                        .append("o=- 8770656990916039506 2 IN IP4 127.0.0.1")
+                        .append(LINE_DIVIDER) // what ever that means
+                        .append("s=")
+                        .append(name)
+                        .append(LINE_DIVIDER)
+                        .append("t=0 0")
+                        .append(LINE_DIVIDER);
+        appendAttributes(s, attributes);
+        for (Media media : this.media) {
+            s.append("m=")
+                    .append(media.media)
+                    .append(' ')
+                    .append(media.port)
+                    .append(' ')
+                    .append(media.protocol)
+                    .append(' ')
+                    .append(Joiner.on(' ').join(media.formats))
+                    .append(LINE_DIVIDER);
+            s.append("c=").append(media.connectionData).append(LINE_DIVIDER);
+            appendAttributes(s, media.attributes);
+        }
+        return s.toString();
+    }
+
+    public static class Media {
+        public final String media;
+        public final int port;
+        public final String protocol;
+        public final List<Integer> formats;
+        public final String connectionData;
+        public final ArrayListMultimap<String, String> attributes;
+
+        public Media(
+                String media,
+                int port,
+                String protocol,
+                List<Integer> formats,
+                String connectionData,
+                ArrayListMultimap<String, String> attributes) {
+            this.media = media;
+            this.port = port;
+            this.protocol = protocol;
+            this.formats = formats;
+            this.connectionData = connectionData;
+            this.attributes = attributes;
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/SessionDescriptionBuilder.java

@@ -0,0 +1,41 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import com.google.common.collect.ArrayListMultimap;
+import java.util.List;
+
+public class SessionDescriptionBuilder {
+    private int version;
+    private String name;
+    private String connectionData;
+    private ArrayListMultimap<String, String> attributes;
+    private List<SessionDescription.Media> media;
+
+    public SessionDescriptionBuilder setVersion(int version) {
+        this.version = version;
+        return this;
+    }
+
+    public SessionDescriptionBuilder setName(String name) {
+        this.name = name;
+        return this;
+    }
+
+    public SessionDescriptionBuilder setConnectionData(String connectionData) {
+        this.connectionData = connectionData;
+        return this;
+    }
+
+    public SessionDescriptionBuilder setAttributes(ArrayListMultimap<String, String> attributes) {
+        this.attributes = attributes;
+        return this;
+    }
+
+    public SessionDescriptionBuilder setMedia(List<SessionDescription.Media> media) {
+        this.media = media;
+        return this;
+    }
+
+    public SessionDescription createSessionDescription() {
+        return new SessionDescription(version, name, connectionData, attributes, media);
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/ToneManager.java

@@ -0,0 +1,274 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import static java.util.Arrays.asList;
+
+import android.content.Context;
+import android.media.AudioManager;
+import android.media.ToneGenerator;
+import android.util.Log;
+import eu.siacs.conversations.Config;
+import im.conversations.android.xmpp.manager.JingleConnectionManager;
+import java.util.Arrays;
+import java.util.Set;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+
+public class ToneManager {
+
+    private final ToneGenerator toneGenerator;
+    private final Context context;
+
+    private ToneState state = null;
+    private RtpEndUserState endUserState = null;
+    private ScheduledFuture<?> currentTone;
+    private ScheduledFuture<?> currentResetFuture;
+    private boolean appRtcAudioManagerHasControl = false;
+
+    private static volatile ToneManager INSTANCE;
+
+    private ToneManager(final Context context) {
+        ToneGenerator toneGenerator;
+        try {
+            toneGenerator = new ToneGenerator(AudioManager.STREAM_VOICE_CALL, 60);
+        } catch (final RuntimeException e) {
+            Log.e(Config.LOGTAG, "unable to instantiate ToneGenerator", e);
+            toneGenerator = null;
+        }
+        this.toneGenerator = toneGenerator;
+        this.context = context.getApplicationContext();
+    }
+
+    private static ToneState of(
+            final boolean isInitiator, final RtpEndUserState state, final Set<Media> media) {
+        if (isInitiator) {
+            if (asList(
+                            RtpEndUserState.FINDING_DEVICE,
+                            RtpEndUserState.RINGING,
+                            RtpEndUserState.CONNECTING)
+                    .contains(state)) {
+                return ToneState.RINGING;
+            }
+            if (state == RtpEndUserState.DECLINED_OR_BUSY) {
+                return ToneState.BUSY;
+            }
+        }
+        if (state == RtpEndUserState.ENDING_CALL) {
+            if (media.contains(Media.VIDEO)) {
+                return ToneState.NULL;
+            } else {
+                return ToneState.ENDING_CALL;
+            }
+        }
+        if (Arrays.asList(
+                        RtpEndUserState.CONNECTED,
+                        RtpEndUserState.RECONNECTING,
+                        RtpEndUserState.INCOMING_CONTENT_ADD)
+                .contains(state)) {
+            if (media.contains(Media.VIDEO)) {
+                return ToneState.NULL;
+            } else {
+                return ToneState.CONNECTED;
+            }
+        }
+        return ToneState.NULL;
+    }
+
+    public void transition(final RtpEndUserState state, final Set<Media> media) {
+        transition(state, of(true, state, media), media);
+    }
+
+    void transition(
+            final boolean isInitiator, final RtpEndUserState state, final Set<Media> media) {
+        transition(state, of(isInitiator, state, media), media);
+    }
+
+    private synchronized void transition(
+            final RtpEndUserState endUserState, final ToneState state, final Set<Media> media) {
+        final RtpEndUserState normalizeEndUserState = normalize(endUserState);
+        if (this.endUserState == normalizeEndUserState) {
+            return;
+        }
+        this.endUserState = normalizeEndUserState;
+        if (this.state == state) {
+            return;
+        }
+        if (state == ToneState.NULL && this.state == ToneState.ENDING_CALL) {
+            return;
+        }
+        cancelCurrentTone();
+        Log.d(Config.LOGTAG, getClass().getName() + ".transition(" + state + ")");
+        if (state != ToneState.NULL) {
+            configureAudioManagerForCall(media);
+        }
+        switch (state) {
+            case RINGING:
+                scheduleWaitingTone();
+                break;
+            case CONNECTED:
+                scheduleConnected();
+                break;
+            case BUSY:
+                scheduleBusy();
+                break;
+            case ENDING_CALL:
+                scheduleEnding();
+                break;
+            case NULL:
+                if (noResetScheduled()) {
+                    resetAudioManager();
+                }
+                break;
+            default:
+                throw new IllegalStateException("Unable to handle transition to " + state);
+        }
+        this.state = state;
+    }
+
+    private static RtpEndUserState normalize(final RtpEndUserState endUserState) {
+        if (Arrays.asList(
+                        RtpEndUserState.CONNECTED,
+                        RtpEndUserState.RECONNECTING,
+                        RtpEndUserState.INCOMING_CONTENT_ADD)
+                .contains(endUserState)) {
+            return RtpEndUserState.CONNECTED;
+        } else {
+            return endUserState;
+        }
+    }
+
+    void setAppRtcAudioManagerHasControl(final boolean appRtcAudioManagerHasControl) {
+        this.appRtcAudioManagerHasControl = appRtcAudioManagerHasControl;
+    }
+
+    private void scheduleConnected() {
+        this.currentTone =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.schedule(
+                        () -> {
+                            startTone(ToneGenerator.TONE_PROP_PROMPT, 200);
+                        },
+                        0,
+                        TimeUnit.SECONDS);
+    }
+
+    private void scheduleEnding() {
+        this.currentTone =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.schedule(
+                        () -> {
+                            startTone(ToneGenerator.TONE_CDMA_CALLDROP_LITE, 375);
+                        },
+                        0,
+                        TimeUnit.SECONDS);
+        this.currentResetFuture =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.schedule(
+                        this::resetAudioManager, 375, TimeUnit.MILLISECONDS);
+    }
+
+    private void scheduleBusy() {
+        this.currentTone =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.schedule(
+                        () -> {
+                            startTone(ToneGenerator.TONE_CDMA_NETWORK_BUSY, 2500);
+                        },
+                        0,
+                        TimeUnit.SECONDS);
+        this.currentResetFuture =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.schedule(
+                        this::resetAudioManager, 2500, TimeUnit.MILLISECONDS);
+    }
+
+    private void scheduleWaitingTone() {
+        this.currentTone =
+                JingleConnectionManager.SCHEDULED_EXECUTOR_SERVICE.scheduleAtFixedRate(
+                        () -> {
+                            startTone(ToneGenerator.TONE_CDMA_DIAL_TONE_LITE, 750);
+                        },
+                        0,
+                        3,
+                        TimeUnit.SECONDS);
+    }
+
+    private boolean noResetScheduled() {
+        return this.currentResetFuture == null || this.currentResetFuture.isDone();
+    }
+
+    private void cancelCurrentTone() {
+        if (currentTone != null) {
+            currentTone.cancel(true);
+        }
+        if (toneGenerator != null) {
+            toneGenerator.stopTone();
+        }
+    }
+
+    private void startTone(final int toneType, final int durationMs) {
+        if (toneGenerator != null) {
+            this.toneGenerator.startTone(toneType, durationMs);
+        } else {
+            Log.e(Config.LOGTAG, "failed to start tone. ToneGenerator doesn't exist");
+        }
+    }
+
+    private void configureAudioManagerForCall(final Set<Media> media) {
+        if (appRtcAudioManagerHasControl) {
+            Log.d(
+                    Config.LOGTAG,
+                    ToneManager.class.getName()
+                            + ": do not configure audio manager because RTC has control");
+            return;
+        }
+        final AudioManager audioManager =
+                (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+        if (audioManager == null) {
+            return;
+        }
+        final boolean isSpeakerPhone = media.contains(Media.VIDEO);
+        Log.d(
+                Config.LOGTAG,
+                ToneManager.class.getName()
+                        + ": putting AudioManager into communication mode. speaker="
+                        + isSpeakerPhone);
+        audioManager.setMode(AudioManager.MODE_IN_COMMUNICATION);
+        audioManager.setSpeakerphoneOn(isSpeakerPhone);
+    }
+
+    private void resetAudioManager() {
+        if (appRtcAudioManagerHasControl) {
+            Log.d(
+                    Config.LOGTAG,
+                    ToneManager.class.getName()
+                            + ": do not reset audio manager because RTC has control");
+            return;
+        }
+        final AudioManager audioManager =
+                (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+        if (audioManager == null) {
+            return;
+        }
+        Log.d(
+                Config.LOGTAG,
+                ToneManager.class.getName() + ": putting AudioManager back into normal mode");
+        audioManager.setMode(AudioManager.MODE_NORMAL);
+        audioManager.setSpeakerphoneOn(false);
+    }
+
+    public static ToneManager getInstance(final Context context) {
+        if (INSTANCE != null) {
+            return INSTANCE;
+        }
+        synchronized (ToneManager.class) {
+            if (INSTANCE != null) {
+                return INSTANCE;
+            }
+            INSTANCE = new ToneManager(context);
+            return INSTANCE;
+        }
+    }
+
+    private enum ToneState {
+        NULL,
+        RINGING,
+        CONNECTED,
+        BUSY,
+        ENDING_CALL
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/TrackWrapper.java

@@ -0,0 +1,71 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.util.Log;
+import com.google.common.base.CaseFormat;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import eu.siacs.conversations.Config;
+import java.util.UUID;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import org.webrtc.MediaStreamTrack;
+import org.webrtc.PeerConnection;
+import org.webrtc.RtpSender;
+import org.webrtc.RtpTransceiver;
+
+class TrackWrapper<T extends MediaStreamTrack> {
+    public final T track;
+    public final RtpSender rtpSender;
+
+    private TrackWrapper(final T track, final RtpSender rtpSender) {
+        Preconditions.checkNotNull(track);
+        Preconditions.checkNotNull(rtpSender);
+        this.track = track;
+        this.rtpSender = rtpSender;
+    }
+
+    public static <T extends MediaStreamTrack> TrackWrapper<T> addTrack(
+            final PeerConnection peerConnection, final T mediaStreamTrack) {
+        final RtpSender rtpSender = peerConnection.addTrack(mediaStreamTrack);
+        return new TrackWrapper<>(mediaStreamTrack, rtpSender);
+    }
+
+    public static <T extends MediaStreamTrack> Optional<T> get(
+            @Nullable final PeerConnection peerConnection, final TrackWrapper<T> trackWrapper) {
+        if (trackWrapper == null) {
+            return Optional.absent();
+        }
+        final RtpTransceiver transceiver =
+                peerConnection == null ? null : getTransceiver(peerConnection, trackWrapper);
+        if (transceiver == null) {
+            Log.w(Config.LOGTAG, "unable to detect transceiver for " + trackWrapper.rtpSender.id());
+            return Optional.of(trackWrapper.track);
+        }
+        final RtpTransceiver.RtpTransceiverDirection direction = transceiver.getDirection();
+        if (direction == RtpTransceiver.RtpTransceiverDirection.SEND_ONLY
+                || direction == RtpTransceiver.RtpTransceiverDirection.SEND_RECV) {
+            return Optional.of(trackWrapper.track);
+        } else {
+            Log.d(Config.LOGTAG, "withholding track because transceiver is " + direction);
+            return Optional.absent();
+        }
+    }
+
+    public static <T extends MediaStreamTrack> RtpTransceiver getTransceiver(
+            @Nonnull final PeerConnection peerConnection, final TrackWrapper<T> trackWrapper) {
+        final RtpSender rtpSender = trackWrapper.rtpSender;
+        for (final RtpTransceiver transceiver : peerConnection.getTransceivers()) {
+            if (transceiver.getSender().id().equals(rtpSender.id())) {
+                return transceiver;
+            }
+        }
+        return null;
+    }
+
+    public static String id(final Class<? extends MediaStreamTrack> clazz) {
+        return String.format(
+                "%s-%s",
+                CaseFormat.UPPER_CAMEL.to(CaseFormat.LOWER_HYPHEN, clazz.getSimpleName()),
+                UUID.randomUUID().toString());
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/VideoSourceWrapper.java

@@ -0,0 +1,182 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.content.Context;
+import android.util.Log;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.SettableFuture;
+import eu.siacs.conversations.Config;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Set;
+import javax.annotation.Nullable;
+import org.webrtc.Camera2Enumerator;
+import org.webrtc.CameraEnumerationAndroid;
+import org.webrtc.CameraEnumerator;
+import org.webrtc.CameraVideoCapturer;
+import org.webrtc.EglBase;
+import org.webrtc.PeerConnectionFactory;
+import org.webrtc.SurfaceTextureHelper;
+import org.webrtc.VideoSource;
+
+class VideoSourceWrapper {
+
+    private static final int CAPTURING_RESOLUTION = 1920;
+    private static final int CAPTURING_MAX_FRAME_RATE = 30;
+
+    private final CameraVideoCapturer cameraVideoCapturer;
+    private final CameraEnumerationAndroid.CaptureFormat captureFormat;
+    private final Set<String> availableCameras;
+    private boolean isFrontCamera = false;
+    private VideoSource videoSource;
+
+    VideoSourceWrapper(
+            CameraVideoCapturer cameraVideoCapturer,
+            CameraEnumerationAndroid.CaptureFormat captureFormat,
+            Set<String> cameras) {
+        this.cameraVideoCapturer = cameraVideoCapturer;
+        this.captureFormat = captureFormat;
+        this.availableCameras = cameras;
+    }
+
+    private int getFrameRate() {
+        return Math.max(
+                captureFormat.framerate.min,
+                Math.min(CAPTURING_MAX_FRAME_RATE, captureFormat.framerate.max));
+    }
+
+    public void initialize(
+            final PeerConnectionFactory peerConnectionFactory,
+            final Context context,
+            final EglBase.Context eglBaseContext) {
+        final SurfaceTextureHelper surfaceTextureHelper =
+                SurfaceTextureHelper.create("webrtc", eglBaseContext);
+        this.videoSource = peerConnectionFactory.createVideoSource(false);
+        this.cameraVideoCapturer.initialize(
+                surfaceTextureHelper, context, this.videoSource.getCapturerObserver());
+    }
+
+    public VideoSource getVideoSource() {
+        final VideoSource videoSource = this.videoSource;
+        if (videoSource == null) {
+            throw new IllegalStateException("VideoSourceWrapper was not initialized");
+        }
+        return videoSource;
+    }
+
+    public void startCapture() {
+        final int frameRate = getFrameRate();
+        Log.d(
+                Config.LOGTAG,
+                String.format(
+                        "start capturing at %dx%d@%d",
+                        captureFormat.width, captureFormat.height, frameRate));
+        this.cameraVideoCapturer.startCapture(captureFormat.width, captureFormat.height, frameRate);
+    }
+
+    public void stopCapture() throws InterruptedException {
+        this.cameraVideoCapturer.stopCapture();
+    }
+
+    public void dispose() {
+        this.cameraVideoCapturer.dispose();
+        if (this.videoSource != null) {
+            dispose(this.videoSource);
+        }
+    }
+
+    private static void dispose(final VideoSource videoSource) {
+        try {
+            videoSource.dispose();
+        } catch (final IllegalStateException e) {
+            Log.e(Config.LOGTAG, "unable to dispose video source", e);
+        }
+    }
+
+    public ListenableFuture<Boolean> switchCamera() {
+        final SettableFuture<Boolean> future = SettableFuture.create();
+        this.cameraVideoCapturer.switchCamera(
+                new CameraVideoCapturer.CameraSwitchHandler() {
+                    @Override
+                    public void onCameraSwitchDone(final boolean isFrontCamera) {
+                        VideoSourceWrapper.this.isFrontCamera = isFrontCamera;
+                        future.set(isFrontCamera);
+                    }
+
+                    @Override
+                    public void onCameraSwitchError(final String message) {
+                        future.setException(
+                                new IllegalStateException(
+                                        String.format("Unable to switch camera %s", message)));
+                    }
+                });
+        return future;
+    }
+
+    public boolean isFrontCamera() {
+        return this.isFrontCamera;
+    }
+
+    public boolean isCameraSwitchable() {
+        return this.availableCameras.size() > 1;
+    }
+
+    public static class Factory {
+        final Context context;
+
+        public Factory(final Context context) {
+            this.context = context;
+        }
+
+        public VideoSourceWrapper create() {
+            final CameraEnumerator enumerator = new Camera2Enumerator(context);
+            final Set<String> deviceNames = ImmutableSet.copyOf(enumerator.getDeviceNames());
+            for (final String deviceName : deviceNames) {
+                if (isFrontFacing(enumerator, deviceName)) {
+                    final VideoSourceWrapper videoSourceWrapper =
+                            of(enumerator, deviceName, deviceNames);
+                    if (videoSourceWrapper == null) {
+                        return null;
+                    }
+                    videoSourceWrapper.isFrontCamera = true;
+                    return videoSourceWrapper;
+                }
+            }
+            if (deviceNames.size() == 0) {
+                return null;
+            } else {
+                return of(enumerator, Iterables.get(deviceNames, 0), deviceNames);
+            }
+        }
+
+        @Nullable
+        private VideoSourceWrapper of(
+                final CameraEnumerator enumerator,
+                final String deviceName,
+                final Set<String> availableCameras) {
+            final CameraVideoCapturer capturer = enumerator.createCapturer(deviceName, null);
+            if (capturer == null) {
+                return null;
+            }
+            final ArrayList<CameraEnumerationAndroid.CaptureFormat> choices =
+                    new ArrayList<>(enumerator.getSupportedFormats(deviceName));
+            Collections.sort(choices, (a, b) -> b.width - a.width);
+            for (final CameraEnumerationAndroid.CaptureFormat captureFormat : choices) {
+                if (captureFormat.width <= CAPTURING_RESOLUTION) {
+                    return new VideoSourceWrapper(capturer, captureFormat, availableCameras);
+                }
+            }
+            return null;
+        }
+
+        private static boolean isFrontFacing(
+                final CameraEnumerator cameraEnumerator, final String deviceName) {
+            try {
+                return cameraEnumerator.isFrontFacing(deviceName);
+            } catch (final NullPointerException e) {
+                return false;
+            }
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/WebRTCWrapper.java

@@ -0,0 +1,750 @@
+package eu.siacs.conversations.xmpp.jingle;
+
+import android.content.Context;
+import android.os.Build;
+import android.os.Handler;
+import android.os.Looper;
+import android.util.Log;
+import com.google.common.base.Optional;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.MoreExecutors;
+import com.google.common.util.concurrent.SettableFuture;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.services.AppRTCAudioManager;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+import java.util.Set;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicBoolean;
+import javax.annotation.Nonnull;
+import javax.annotation.Nullable;
+import org.webrtc.AudioSource;
+import org.webrtc.AudioTrack;
+import org.webrtc.CandidatePairChangeEvent;
+import org.webrtc.DataChannel;
+import org.webrtc.DefaultVideoDecoderFactory;
+import org.webrtc.DefaultVideoEncoderFactory;
+import org.webrtc.EglBase;
+import org.webrtc.IceCandidate;
+import org.webrtc.MediaConstraints;
+import org.webrtc.MediaStream;
+import org.webrtc.MediaStreamTrack;
+import org.webrtc.PeerConnection;
+import org.webrtc.PeerConnectionFactory;
+import org.webrtc.RtpReceiver;
+import org.webrtc.RtpTransceiver;
+import org.webrtc.SdpObserver;
+import org.webrtc.SessionDescription;
+import org.webrtc.VideoTrack;
+import org.webrtc.audio.JavaAudioDeviceModule;
+import org.webrtc.voiceengine.WebRtcAudioEffects;
+
+@SuppressWarnings("UnstableApiUsage")
+public class WebRTCWrapper {
+
+    private static final String EXTENDED_LOGGING_TAG = WebRTCWrapper.class.getSimpleName();
+
+    private final ExecutorService executorService = Executors.newSingleThreadExecutor();
+
+    private static final Set<String> HARDWARE_AEC_BLACKLIST =
+            new ImmutableSet.Builder<String>()
+                    .add("Pixel")
+                    .add("Pixel XL")
+                    .add("Moto G5")
+                    .add("Moto G (5S) Plus")
+                    .add("Moto G4")
+                    .add("TA-1053")
+                    .add("Mi A1")
+                    .add("Mi A2")
+                    .add("E5823") // Sony z5 compact
+                    .add("Redmi Note 5")
+                    .add("FP2") // Fairphone FP2
+                    .add("MI 5")
+                    .add("GT-I9515") // Samsung Galaxy S4 Value Edition (jfvelte)
+                    .add("GT-I9515L") // Samsung Galaxy S4 Value Edition (jfvelte)
+                    .add("GT-I9505") // Samsung Galaxy S4 (jfltexx)
+                    .build();
+
+    private final EventCallback eventCallback;
+    private final AtomicBoolean readyToReceivedIceCandidates = new AtomicBoolean(false);
+    private final Queue<IceCandidate> iceCandidates = new LinkedList<>();
+    private final AppRTCAudioManager.AudioManagerEvents audioManagerEvents =
+            new AppRTCAudioManager.AudioManagerEvents() {
+                @Override
+                public void onAudioDeviceChanged(
+                        AppRTCAudioManager.AudioDevice selectedAudioDevice,
+                        Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
+                    eventCallback.onAudioDeviceChanged(selectedAudioDevice, availableAudioDevices);
+                }
+            };
+    private final Handler mainHandler = new Handler(Looper.getMainLooper());
+    private TrackWrapper<AudioTrack> localAudioTrack = null;
+    private TrackWrapper<VideoTrack> localVideoTrack = null;
+    private VideoTrack remoteVideoTrack = null;
+    private final PeerConnection.Observer peerConnectionObserver =
+            new PeerConnection.Observer() {
+                @Override
+                public void onSignalingChange(PeerConnection.SignalingState signalingState) {
+                    Log.d(EXTENDED_LOGGING_TAG, "onSignalingChange(" + signalingState + ")");
+                    // this is called after removeTrack or addTrack
+                    // and should then trigger a content-add or content-remove or something
+                    // https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/removeTrack
+                }
+
+                @Override
+                public void onConnectionChange(final PeerConnection.PeerConnectionState newState) {
+                    eventCallback.onConnectionChange(newState);
+                }
+
+                @Override
+                public void onIceConnectionChange(
+                        PeerConnection.IceConnectionState iceConnectionState) {
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onIceConnectionChange(" + iceConnectionState + ")");
+                }
+
+                @Override
+                public void onSelectedCandidatePairChanged(CandidatePairChangeEvent event) {
+                    Log.d(Config.LOGTAG, "remote candidate selected: " + event.remote);
+                    Log.d(Config.LOGTAG, "local candidate selected: " + event.local);
+                }
+
+                @Override
+                public void onIceConnectionReceivingChange(boolean b) {}
+
+                @Override
+                public void onIceGatheringChange(
+                        PeerConnection.IceGatheringState iceGatheringState) {
+                    Log.d(EXTENDED_LOGGING_TAG, "onIceGatheringChange(" + iceGatheringState + ")");
+                }
+
+                @Override
+                public void onIceCandidate(IceCandidate iceCandidate) {
+                    if (readyToReceivedIceCandidates.get()) {
+                        eventCallback.onIceCandidate(iceCandidate);
+                    } else {
+                        iceCandidates.add(iceCandidate);
+                    }
+                }
+
+                @Override
+                public void onIceCandidatesRemoved(IceCandidate[] iceCandidates) {}
+
+                @Override
+                public void onAddStream(MediaStream mediaStream) {
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onAddStream(numAudioTracks="
+                                    + mediaStream.audioTracks.size()
+                                    + ",numVideoTracks="
+                                    + mediaStream.videoTracks.size()
+                                    + ")");
+                }
+
+                @Override
+                public void onRemoveStream(MediaStream mediaStream) {}
+
+                @Override
+                public void onDataChannel(DataChannel dataChannel) {}
+
+                @Override
+                public void onRenegotiationNeeded() {
+                    Log.d(EXTENDED_LOGGING_TAG, "onRenegotiationNeeded()");
+                    final PeerConnection.PeerConnectionState currentState =
+                            peerConnection == null ? null : peerConnection.connectionState();
+                    if (currentState != null
+                            && currentState != PeerConnection.PeerConnectionState.NEW) {
+                        eventCallback.onRenegotiationNeeded();
+                    }
+                }
+
+                @Override
+                public void onAddTrack(RtpReceiver rtpReceiver, MediaStream[] mediaStreams) {
+                    final MediaStreamTrack track = rtpReceiver.track();
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onAddTrack(kind="
+                                    + (track == null ? "null" : track.kind())
+                                    + ",numMediaStreams="
+                                    + mediaStreams.length
+                                    + ")");
+                    if (track instanceof VideoTrack) {
+                        remoteVideoTrack = (VideoTrack) track;
+                    }
+                }
+
+                @Override
+                public void onTrack(final RtpTransceiver transceiver) {
+                    Log.d(
+                            EXTENDED_LOGGING_TAG,
+                            "onTrack(mid="
+                                    + transceiver.getMid()
+                                    + ",media="
+                                    + transceiver.getMediaType()
+                                    + ",direction="
+                                    + transceiver.getDirection()
+                                    + ")");
+                }
+
+                @Override
+                public void onRemoveTrack(final RtpReceiver receiver) {
+                    Log.d(EXTENDED_LOGGING_TAG, "onRemoveTrack(" + receiver.id() + ")");
+                }
+            };
+    @Nullable private PeerConnectionFactory peerConnectionFactory = null;
+    @Nullable private PeerConnection peerConnection = null;
+    private AppRTCAudioManager appRTCAudioManager = null;
+    private Context context = null;
+    private EglBase eglBase = null;
+    private VideoSourceWrapper videoSourceWrapper;
+
+    WebRTCWrapper(final EventCallback eventCallback) {
+        this.eventCallback = eventCallback;
+    }
+
+    private static void dispose(final PeerConnection peerConnection) {
+        try {
+            peerConnection.dispose();
+        } catch (final IllegalStateException e) {
+            Log.e(Config.LOGTAG, "unable to dispose of peer connection", e);
+        }
+    }
+
+    public void setup(
+            final Context service,
+            @Nonnull final AppRTCAudioManager.SpeakerPhonePreference speakerPhonePreference)
+            throws InitializationException {
+        try {
+            PeerConnectionFactory.initialize(
+                    PeerConnectionFactory.InitializationOptions.builder(service)
+                            .setFieldTrials("WebRTC-BindUsingInterfaceName/Enabled/")
+                            .createInitializationOptions());
+        } catch (final UnsatisfiedLinkError e) {
+            throw new InitializationException("Unable to initialize PeerConnectionFactory", e);
+        }
+        try {
+            this.eglBase = EglBase.create();
+        } catch (final RuntimeException e) {
+            throw new InitializationException("Unable to create EGL base", e);
+        }
+        this.context = service;
+        mainHandler.post(
+                () -> {
+                    appRTCAudioManager = AppRTCAudioManager.create(service, speakerPhonePreference);
+                    ToneManager.getInstance(context).setAppRtcAudioManagerHasControl(true);
+                    appRTCAudioManager.start(audioManagerEvents);
+                    eventCallback.onAudioDeviceChanged(
+                            appRTCAudioManager.getSelectedAudioDevice(),
+                            appRTCAudioManager.getAudioDevices());
+                });
+    }
+
+    synchronized void initializePeerConnection(
+            final Set<Media> media, final List<PeerConnection.IceServer> iceServers)
+            throws InitializationException {
+        Preconditions.checkState(this.eglBase != null);
+        Preconditions.checkNotNull(media);
+        Preconditions.checkArgument(
+                media.size() > 0, "media can not be empty when initializing peer connection");
+        final boolean setUseHardwareAcousticEchoCanceler =
+                WebRtcAudioEffects.canUseAcousticEchoCanceler()
+                        && !HARDWARE_AEC_BLACKLIST.contains(Build.MODEL);
+        Log.d(
+                Config.LOGTAG,
+                String.format(
+                        "setUseHardwareAcousticEchoCanceler(%s) model=%s",
+                        setUseHardwareAcousticEchoCanceler, Build.MODEL));
+        this.peerConnectionFactory =
+                PeerConnectionFactory.builder()
+                        .setVideoDecoderFactory(
+                                new DefaultVideoDecoderFactory(eglBase.getEglBaseContext()))
+                        .setVideoEncoderFactory(
+                                new DefaultVideoEncoderFactory(
+                                        eglBase.getEglBaseContext(), true, true))
+                        .setAudioDeviceModule(
+                                JavaAudioDeviceModule.builder(requireContext())
+                                        .setUseHardwareAcousticEchoCanceler(
+                                                setUseHardwareAcousticEchoCanceler)
+                                        .createAudioDeviceModule())
+                        .createPeerConnectionFactory();
+
+        final PeerConnection.RTCConfiguration rtcConfig = buildConfiguration(iceServers);
+        final PeerConnection peerConnection =
+                requirePeerConnectionFactory()
+                        .createPeerConnection(rtcConfig, peerConnectionObserver);
+        if (peerConnection == null) {
+            throw new InitializationException("Unable to create PeerConnection");
+        }
+
+        if (media.contains(Media.VIDEO)) {
+            addVideoTrack(peerConnection);
+        }
+
+        if (media.contains(Media.AUDIO)) {
+            addAudioTrack(peerConnection);
+        }
+        peerConnection.setAudioPlayout(true);
+        peerConnection.setAudioRecording(true);
+
+        this.peerConnection = peerConnection;
+    }
+
+    private VideoSourceWrapper initializeVideoSourceWrapper() {
+        final VideoSourceWrapper existingVideoSourceWrapper = this.videoSourceWrapper;
+        if (existingVideoSourceWrapper != null) {
+            existingVideoSourceWrapper.startCapture();
+            return existingVideoSourceWrapper;
+        }
+        final VideoSourceWrapper videoSourceWrapper =
+                new VideoSourceWrapper.Factory(requireContext()).create();
+        if (videoSourceWrapper == null) {
+            throw new IllegalStateException("Could not instantiate VideoSourceWrapper");
+        }
+        videoSourceWrapper.initialize(
+                requirePeerConnectionFactory(), requireContext(), eglBase.getEglBaseContext());
+        videoSourceWrapper.startCapture();
+        this.videoSourceWrapper = videoSourceWrapper;
+        return videoSourceWrapper;
+    }
+
+    public synchronized boolean addTrack(final Media media) {
+        if (media == Media.VIDEO) {
+            return addVideoTrack(requirePeerConnection());
+        } else if (media == Media.AUDIO) {
+            return addAudioTrack(requirePeerConnection());
+        }
+        throw new IllegalStateException(String.format("Could not add track for %s", media));
+    }
+
+    public synchronized void removeTrack(final Media media) {
+        if (media == Media.VIDEO) {
+            removeVideoTrack(requirePeerConnection());
+        }
+    }
+
+    private boolean addAudioTrack(final PeerConnection peerConnection) {
+        final AudioSource audioSource =
+                requirePeerConnectionFactory().createAudioSource(new MediaConstraints());
+        final AudioTrack audioTrack =
+                requirePeerConnectionFactory()
+                        .createAudioTrack(TrackWrapper.id(AudioTrack.class), audioSource);
+        this.localAudioTrack = TrackWrapper.addTrack(peerConnection, audioTrack);
+        return true;
+    }
+
+    private boolean addVideoTrack(final PeerConnection peerConnection) {
+        final TrackWrapper<VideoTrack> existing = this.localVideoTrack;
+        if (existing != null) {
+            final RtpTransceiver transceiver =
+                    TrackWrapper.getTransceiver(peerConnection, existing);
+            if (transceiver == null) {
+                Log.w(EXTENDED_LOGGING_TAG, "unable to restart video transceiver");
+                return false;
+            }
+            transceiver.setDirection(RtpTransceiver.RtpTransceiverDirection.SEND_RECV);
+            this.videoSourceWrapper.startCapture();
+            return true;
+        }
+        final VideoSourceWrapper videoSourceWrapper;
+        try {
+            videoSourceWrapper = initializeVideoSourceWrapper();
+        } catch (final IllegalStateException e) {
+            Log.d(Config.LOGTAG, "could not add video track", e);
+            return false;
+        }
+        final VideoTrack videoTrack =
+                requirePeerConnectionFactory()
+                        .createVideoTrack(
+                                TrackWrapper.id(VideoTrack.class),
+                                videoSourceWrapper.getVideoSource());
+        this.localVideoTrack = TrackWrapper.addTrack(peerConnection, videoTrack);
+        return true;
+    }
+
+    private void removeVideoTrack(final PeerConnection peerConnection) {
+        final TrackWrapper<VideoTrack> localVideoTrack = this.localVideoTrack;
+        if (localVideoTrack != null) {
+
+            final RtpTransceiver exactTransceiver =
+                    TrackWrapper.getTransceiver(peerConnection, localVideoTrack);
+            if (exactTransceiver == null) {
+                throw new IllegalStateException();
+            }
+            exactTransceiver.setDirection(RtpTransceiver.RtpTransceiverDirection.INACTIVE);
+        }
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
+        if (videoSourceWrapper != null) {
+            try {
+                videoSourceWrapper.stopCapture();
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+    }
+
+    private static PeerConnection.RTCConfiguration buildConfiguration(
+            final List<PeerConnection.IceServer> iceServers) {
+        final PeerConnection.RTCConfiguration rtcConfig =
+                new PeerConnection.RTCConfiguration(iceServers);
+        rtcConfig.tcpCandidatePolicy =
+                PeerConnection.TcpCandidatePolicy.DISABLED; // XEP-0176 doesn't support tcp
+        rtcConfig.continualGatheringPolicy =
+                PeerConnection.ContinualGatheringPolicy.GATHER_CONTINUALLY;
+        rtcConfig.sdpSemantics = PeerConnection.SdpSemantics.UNIFIED_PLAN;
+        rtcConfig.rtcpMuxPolicy = PeerConnection.RtcpMuxPolicy.NEGOTIATE;
+        rtcConfig.enableImplicitRollback = true;
+        return rtcConfig;
+    }
+
+    void reconfigurePeerConnection(final List<PeerConnection.IceServer> iceServers) {
+        requirePeerConnection().setConfiguration(buildConfiguration(iceServers));
+    }
+
+    void restartIce() {
+        executorService.execute(
+                () -> {
+                    final PeerConnection peerConnection;
+                    try {
+                        peerConnection = requirePeerConnection();
+                    } catch (final PeerConnectionNotInitialized e) {
+                        Log.w(
+                                EXTENDED_LOGGING_TAG,
+                                "PeerConnection vanished before we could execute restart");
+                        return;
+                    }
+                    setIsReadyToReceiveIceCandidates(false);
+                    peerConnection.restartIce();
+                });
+    }
+
+    public void setIsReadyToReceiveIceCandidates(final boolean ready) {
+        readyToReceivedIceCandidates.set(ready);
+        final int was = iceCandidates.size();
+        while (ready && iceCandidates.peek() != null) {
+            eventCallback.onIceCandidate(iceCandidates.poll());
+        }
+        final int is = iceCandidates.size();
+        Log.d(
+                EXTENDED_LOGGING_TAG,
+                "setIsReadyToReceiveCandidates(" + ready + ") was=" + was + " is=" + is);
+    }
+
+    synchronized void close() {
+        final PeerConnection peerConnection = this.peerConnection;
+        final PeerConnectionFactory peerConnectionFactory = this.peerConnectionFactory;
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
+        final AppRTCAudioManager audioManager = this.appRTCAudioManager;
+        final EglBase eglBase = this.eglBase;
+        if (peerConnection != null) {
+            this.peerConnection = null;
+            dispose(peerConnection);
+        }
+        if (audioManager != null) {
+            ToneManager.getInstance(context).setAppRtcAudioManagerHasControl(false);
+            mainHandler.post(audioManager::stop);
+        }
+        this.localVideoTrack = null;
+        this.remoteVideoTrack = null;
+        if (videoSourceWrapper != null) {
+            this.videoSourceWrapper = null;
+            try {
+                videoSourceWrapper.stopCapture();
+            } catch (final InterruptedException e) {
+                Log.e(Config.LOGTAG, "unable to stop capturing");
+            }
+            videoSourceWrapper.dispose();
+        }
+        if (eglBase != null) {
+            eglBase.release();
+            this.eglBase = null;
+        }
+        if (peerConnectionFactory != null) {
+            this.peerConnectionFactory = null;
+            peerConnectionFactory.dispose();
+        }
+    }
+
+    synchronized void verifyClosed() {
+        if (this.peerConnection != null
+                || this.eglBase != null
+                || this.localVideoTrack != null
+                || this.remoteVideoTrack != null) {
+            final IllegalStateException e =
+                    new IllegalStateException("WebRTCWrapper hasn't been closed properly");
+            Log.e(Config.LOGTAG, "verifyClosed() failed. Going to throw", e);
+            throw e;
+        }
+    }
+
+    boolean isCameraSwitchable() {
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
+        return videoSourceWrapper != null && videoSourceWrapper.isCameraSwitchable();
+    }
+
+    boolean isFrontCamera() {
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
+        return videoSourceWrapper == null || videoSourceWrapper.isFrontCamera();
+    }
+
+    ListenableFuture<Boolean> switchCamera() {
+        final VideoSourceWrapper videoSourceWrapper = this.videoSourceWrapper;
+        if (videoSourceWrapper == null) {
+            return Futures.immediateFailedFuture(
+                    new IllegalStateException("VideoSourceWrapper has not been initialized"));
+        }
+        return videoSourceWrapper.switchCamera();
+    }
+
+    boolean isMicrophoneEnabled() {
+        final Optional<AudioTrack> audioTrack =
+                TrackWrapper.get(peerConnection, this.localAudioTrack);
+        if (audioTrack.isPresent()) {
+            try {
+                return audioTrack.get().enabled();
+            } catch (final IllegalStateException e) {
+                // sometimes UI might still be rendering the buttons when a background thread has
+                // already ended the call
+                return false;
+            }
+        } else {
+            throw new IllegalStateException("Local audio track does not exist (yet)");
+        }
+    }
+
+    boolean setMicrophoneEnabled(final boolean enabled) {
+        final Optional<AudioTrack> audioTrack =
+                TrackWrapper.get(peerConnection, this.localAudioTrack);
+        if (audioTrack.isPresent()) {
+            try {
+                audioTrack.get().setEnabled(enabled);
+                return true;
+            } catch (final IllegalStateException e) {
+                Log.d(Config.LOGTAG, "unable to toggle microphone", e);
+                // ignoring race condition in case MediaStreamTrack has been disposed
+                return false;
+            }
+        } else {
+            throw new IllegalStateException("Local audio track does not exist (yet)");
+        }
+    }
+
+    boolean isVideoEnabled() {
+        final Optional<VideoTrack> videoTrack =
+                TrackWrapper.get(peerConnection, this.localVideoTrack);
+        if (videoTrack.isPresent()) {
+            return videoTrack.get().enabled();
+        }
+        return false;
+    }
+
+    void setVideoEnabled(final boolean enabled) {
+        final Optional<VideoTrack> videoTrack =
+                TrackWrapper.get(peerConnection, this.localVideoTrack);
+        if (videoTrack.isPresent()) {
+            videoTrack.get().setEnabled(enabled);
+            return;
+        }
+        throw new IllegalStateException("Local video track does not exist");
+    }
+
+    synchronized ListenableFuture<SessionDescription> setLocalDescription() {
+        return Futures.transformAsync(
+                getPeerConnectionFuture(),
+                peerConnection -> {
+                    if (peerConnection == null) {
+                        return Futures.immediateFailedFuture(
+                                new IllegalStateException("PeerConnection was null"));
+                    }
+                    final SettableFuture<SessionDescription> future = SettableFuture.create();
+                    peerConnection.setLocalDescription(
+                            new SetSdpObserver() {
+                                @Override
+                                public void onSetSuccess() {
+                                    final SessionDescription description =
+                                            peerConnection.getLocalDescription();
+                                    Log.d(EXTENDED_LOGGING_TAG, "set local description:");
+                                    logDescription(description);
+                                    future.set(description);
+                                }
+
+                                @Override
+                                public void onSetFailure(final String message) {
+                                    future.setException(
+                                            new FailureToSetDescriptionException(message));
+                                }
+                            });
+                    return future;
+                },
+                MoreExecutors.directExecutor());
+    }
+
+    public static void logDescription(final SessionDescription sessionDescription) {
+        for (final String line :
+                sessionDescription.description.split(
+                        eu.siacs.conversations.xmpp.jingle.SessionDescription.LINE_DIVIDER)) {
+            Log.d(EXTENDED_LOGGING_TAG, line);
+        }
+    }
+
+    synchronized ListenableFuture<Void> setRemoteDescription(
+            final SessionDescription sessionDescription) {
+        Log.d(EXTENDED_LOGGING_TAG, "setting remote description:");
+        logDescription(sessionDescription);
+        return Futures.transformAsync(
+                getPeerConnectionFuture(),
+                peerConnection -> {
+                    if (peerConnection == null) {
+                        return Futures.immediateFailedFuture(
+                                new IllegalStateException("PeerConnection was null"));
+                    }
+                    final SettableFuture<Void> future = SettableFuture.create();
+                    peerConnection.setRemoteDescription(
+                            new SetSdpObserver() {
+                                @Override
+                                public void onSetSuccess() {
+                                    future.set(null);
+                                }
+
+                                @Override
+                                public void onSetFailure(final String message) {
+                                    future.setException(
+                                            new FailureToSetDescriptionException(message));
+                                }
+                            },
+                            sessionDescription);
+                    return future;
+                },
+                MoreExecutors.directExecutor());
+    }
+
+    @Nonnull
+    private ListenableFuture<PeerConnection> getPeerConnectionFuture() {
+        final PeerConnection peerConnection = this.peerConnection;
+        if (peerConnection == null) {
+            return Futures.immediateFailedFuture(new PeerConnectionNotInitialized());
+        } else {
+            return Futures.immediateFuture(peerConnection);
+        }
+    }
+
+    @Nonnull
+    private PeerConnection requirePeerConnection() {
+        final PeerConnection peerConnection = this.peerConnection;
+        if (peerConnection == null) {
+            throw new PeerConnectionNotInitialized();
+        }
+        return peerConnection;
+    }
+
+    @Nonnull
+    private PeerConnectionFactory requirePeerConnectionFactory() {
+        final PeerConnectionFactory peerConnectionFactory = this.peerConnectionFactory;
+        if (peerConnectionFactory == null) {
+            throw new IllegalStateException("Make sure PeerConnectionFactory is initialized");
+        }
+        return peerConnectionFactory;
+    }
+
+    void addIceCandidate(IceCandidate iceCandidate) {
+        requirePeerConnection().addIceCandidate(iceCandidate);
+    }
+
+    PeerConnection.PeerConnectionState getState() {
+        return requirePeerConnection().connectionState();
+    }
+
+    public PeerConnection.SignalingState getSignalingState() {
+        try {
+            return requirePeerConnection().signalingState();
+        } catch (final IllegalStateException e) {
+            return PeerConnection.SignalingState.CLOSED;
+        }
+    }
+
+    EglBase.Context getEglBaseContext() {
+        return this.eglBase.getEglBaseContext();
+    }
+
+    Optional<VideoTrack> getLocalVideoTrack() {
+        return TrackWrapper.get(peerConnection, this.localVideoTrack);
+    }
+
+    Optional<VideoTrack> getRemoteVideoTrack() {
+        return Optional.fromNullable(this.remoteVideoTrack);
+    }
+
+    private Context requireContext() {
+        final Context context = this.context;
+        if (context == null) {
+            throw new IllegalStateException("call setup first");
+        }
+        return context;
+    }
+
+    AppRTCAudioManager getAudioManager() {
+        return appRTCAudioManager;
+    }
+
+    void execute(final Runnable command) {
+        executorService.execute(command);
+    }
+
+    public void switchSpeakerPhonePreference(AppRTCAudioManager.SpeakerPhonePreference preference) {
+        mainHandler.post(() -> appRTCAudioManager.switchSpeakerPhonePreference(preference));
+    }
+
+    public interface EventCallback {
+        void onIceCandidate(IceCandidate iceCandidate);
+
+        void onConnectionChange(PeerConnection.PeerConnectionState newState);
+
+        void onAudioDeviceChanged(
+                AppRTCAudioManager.AudioDevice selectedAudioDevice,
+                Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
+
+        void onRenegotiationNeeded();
+    }
+
+    private abstract static class SetSdpObserver implements SdpObserver {
+
+        @Override
+        public void onCreateSuccess(org.webrtc.SessionDescription sessionDescription) {
+            throw new IllegalStateException("Not able to use SetSdpObserver");
+        }
+
+        @Override
+        public void onCreateFailure(String s) {
+            throw new IllegalStateException("Not able to use SetSdpObserver");
+        }
+    }
+
+    static class InitializationException extends Exception {
+
+        private InitializationException(final String message, final Throwable throwable) {
+            super(message, throwable);
+        }
+
+        private InitializationException(final String message) {
+            super(message);
+        }
+    }
+
+    public static class PeerConnectionNotInitialized extends IllegalStateException {
+
+        private PeerConnectionNotInitialized() {
+            super("initialize PeerConnection first");
+        }
+    }
+
+    private static class FailureToSetDescriptionException extends IllegalArgumentException {
+        public FailureToSetDescriptionException(String message) {
+            super(message);
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/Content.java

@@ -0,0 +1,170 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import android.util.Log;
+import androidx.annotation.NonNull;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.xmpp.jingle.SessionDescription;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.Locale;
+import java.util.Set;
+
+public class Content extends Element {
+
+    public Content(final Creator creator, final Senders senders, final String name) {
+        super("content", Namespace.JINGLE);
+        this.setAttribute("creator", creator.toString());
+        this.setAttribute("name", name);
+        this.setSenders(senders);
+    }
+
+    private Content() {
+        super("content", Namespace.JINGLE);
+    }
+
+    public static Content upgrade(final Element element) {
+        Preconditions.checkArgument("content".equals(element.getName()));
+        final Content content = new Content();
+        content.setAttributes(element.getAttributes());
+        content.setChildren(element.getChildren());
+        return content;
+    }
+
+    public String getContentName() {
+        return this.getAttribute("name");
+    }
+
+    public Creator getCreator() {
+        return Creator.of(getAttribute("creator"));
+    }
+
+    public Senders getSenders() {
+        final String attribute = getAttribute("senders");
+        if (Strings.isNullOrEmpty(attribute)) {
+            return Senders.BOTH;
+        }
+        return Senders.of(getAttribute("senders"));
+    }
+
+    public void setSenders(final Senders senders) {
+        if (senders != null && senders != Senders.BOTH) {
+            this.setAttribute("senders", senders.toString());
+        }
+    }
+
+    public GenericDescription getDescription() {
+        final Element description = this.findChild("description");
+        if (description == null) {
+            return null;
+        }
+        final String namespace = description.getNamespace();
+        if (FileTransferDescription.NAMESPACES.contains(namespace)) {
+            return FileTransferDescription.upgrade(description);
+        } else if (Namespace.JINGLE_APPS_RTP.equals(namespace)) {
+            return RtpDescription.upgrade(description);
+        } else {
+            return GenericDescription.upgrade(description);
+        }
+    }
+
+    public void setDescription(final GenericDescription description) {
+        Preconditions.checkNotNull(description);
+        this.addChild(description);
+    }
+
+    public String getDescriptionNamespace() {
+        final Element description = this.findChild("description");
+        return description == null ? null : description.getNamespace();
+    }
+
+    public GenericTransportInfo getTransport() {
+        final Element transport = this.findChild("transport");
+        final String namespace = transport == null ? null : transport.getNamespace();
+        if (Namespace.JINGLE_TRANSPORTS_IBB.equals(namespace)) {
+            return IbbTransportInfo.upgrade(transport);
+        } else if (Namespace.JINGLE_TRANSPORTS_S5B.equals(namespace)) {
+            return S5BTransportInfo.upgrade(transport);
+        } else if (Namespace.JINGLE_TRANSPORT_ICE_UDP.equals(namespace)) {
+            return IceUdpTransportInfo.upgrade(transport);
+        } else if (transport != null) {
+            return GenericTransportInfo.upgrade(transport);
+        } else {
+            return null;
+        }
+    }
+
+    public void setTransport(GenericTransportInfo transportInfo) {
+        this.addChild(transportInfo);
+    }
+
+    public enum Creator {
+        INITIATOR,
+        RESPONDER;
+
+        public static Creator of(final String value) {
+            return Creator.valueOf(value.toUpperCase(Locale.ROOT));
+        }
+
+        @Override
+        @NonNull
+        public String toString() {
+            return super.toString().toLowerCase(Locale.ROOT);
+        }
+    }
+
+    public enum Senders {
+        BOTH,
+        INITIATOR,
+        NONE,
+        RESPONDER;
+
+        public static Senders of(final String value) {
+            return Senders.valueOf(value.toUpperCase(Locale.ROOT));
+        }
+
+        public static Senders of(final SessionDescription.Media media, final boolean initiator) {
+            final Set<String> attributes = media.attributes.keySet();
+            if (attributes.contains("sendrecv")) {
+                return BOTH;
+            } else if (attributes.contains("inactive")) {
+                return NONE;
+            } else if (attributes.contains("sendonly")) {
+                return initiator ? INITIATOR : RESPONDER;
+            } else if (attributes.contains("recvonly")) {
+                return initiator ? RESPONDER : INITIATOR;
+            }
+            Log.w(Config.LOGTAG, "assuming default value for senders");
+            // If none of the attributes "sendonly", "recvonly", "inactive", and "sendrecv" is
+            // present, "sendrecv" SHOULD be assumed as the default
+            // https://www.rfc-editor.org/rfc/rfc4566
+            return BOTH;
+        }
+
+        @Override
+        @NonNull
+        public String toString() {
+            return super.toString().toLowerCase(Locale.ROOT);
+        }
+
+        public String asMediaAttribute(final boolean initiator) {
+            final boolean responder = !initiator;
+            if (this == Content.Senders.BOTH) {
+                return "sendrecv";
+            } else if (this == Content.Senders.NONE) {
+                return "inactive";
+            } else if ((initiator && this == Content.Senders.INITIATOR)
+                    || (responder && this == Content.Senders.RESPONDER)) {
+                return "sendonly";
+            } else if ((initiator && this == Content.Senders.RESPONDER)
+                    || (responder && this == Content.Senders.INITIATOR)) {
+                return "recvonly";
+            } else {
+                throw new IllegalStateException(
+                        String.format(
+                                "illegal combination of initiator=%s and %s", initiator, this));
+            }
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/FileTransferDescription.java

@@ -0,0 +1,69 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import im.conversations.android.xml.Element;
+import java.util.Arrays;
+import java.util.List;
+
+public class FileTransferDescription extends GenericDescription {
+
+    public static List<String> NAMESPACES =
+            Arrays.asList(Version.FT_3.namespace, Version.FT_4.namespace, Version.FT_5.namespace);
+
+    private FileTransferDescription(String name, String namespace) {
+        super(name, namespace);
+    }
+
+    public Version getVersion() {
+        final String namespace = getNamespace();
+        if (namespace.equals(Version.FT_3.namespace)) {
+            return Version.FT_3;
+        } else if (namespace.equals(Version.FT_4.namespace)) {
+            return Version.FT_4;
+        } else if (namespace.equals(Version.FT_5.namespace)) {
+            return Version.FT_5;
+        } else {
+            throw new IllegalStateException("Unknown namespace");
+        }
+    }
+
+    public Element getFileOffer() {
+        final Version version = getVersion();
+        if (version == Version.FT_3) {
+            final Element offer = this.findChild("offer");
+            return offer == null ? null : offer.findChild("file");
+        } else {
+            return this.findChild("file");
+        }
+    }
+
+    public static FileTransferDescription upgrade(final Element element) {
+        Preconditions.checkArgument(
+                "description".equals(element.getName()),
+                "Name of provided element is not description");
+        Preconditions.checkArgument(
+                NAMESPACES.contains(element.getNamespace()),
+                "Element does not match a file transfer namespace");
+        final FileTransferDescription description =
+                new FileTransferDescription("description", element.getNamespace());
+        description.setAttributes(element.getAttributes());
+        description.setChildren(element.getChildren());
+        return description;
+    }
+
+    public enum Version {
+        FT_3("urn:xmpp:jingle:apps:file-transfer:3"),
+        FT_4("urn:xmpp:jingle:apps:file-transfer:4"),
+        FT_5("urn:xmpp:jingle:apps:file-transfer:5");
+
+        private final String namespace;
+
+        Version(String namespace) {
+            this.namespace = namespace;
+        }
+
+        public String getNamespace() {
+            return namespace;
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/GenericDescription.java

@@ -0,0 +1,20 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import im.conversations.android.xml.Element;
+
+public class GenericDescription extends Element {
+
+    GenericDescription(String name, final String namespace) {
+        super(name, namespace);
+    }
+
+    public static GenericDescription upgrade(final Element element) {
+        Preconditions.checkArgument("description".equals(element.getName()));
+        final GenericDescription description =
+                new GenericDescription("description", element.getNamespace());
+        description.setAttributes(element.getAttributes());
+        description.setChildren(element.getChildren());
+        return description;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/GenericTransportInfo.java

@@ -0,0 +1,20 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import im.conversations.android.xml.Element;
+
+public class GenericTransportInfo extends Element {
+
+    protected GenericTransportInfo(String name, String xmlns) {
+        super(name, xmlns);
+    }
+
+    public static GenericTransportInfo upgrade(final Element element) {
+        Preconditions.checkArgument("transport".equals(element.getName()));
+        final GenericTransportInfo transport =
+                new GenericTransportInfo("transport", element.getNamespace());
+        transport.setAttributes(element.getAttributes());
+        transport.setChildren(element.getChildren());
+        return transport;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/Group.java

@@ -0,0 +1,62 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.Collection;
+import java.util.List;
+
+public class Group extends Element {
+
+    private Group() {
+        super("group", Namespace.JINGLE_APPS_GROUPING);
+    }
+
+    public Group(final String semantics, final Collection<String> identificationTags) {
+        super("group", Namespace.JINGLE_APPS_GROUPING);
+        this.setAttribute("semantics", semantics);
+        for (String tag : identificationTags) {
+            this.addChild(new Element("content").setAttribute("name", tag));
+        }
+    }
+
+    public String getSemantics() {
+        return this.getAttribute("semantics");
+    }
+
+    public List<String> getIdentificationTags() {
+        final ImmutableList.Builder<String> builder = new ImmutableList.Builder<>();
+        for (final Element child : this.children) {
+            if ("content".equals(child.getName())) {
+                final String name = child.getAttribute("name");
+                if (name != null) {
+                    builder.add(name);
+                }
+            }
+        }
+        return builder.build();
+    }
+
+    public static Group ofSdpString(final String input) {
+        ImmutableList.Builder<String> tagBuilder = new ImmutableList.Builder<>();
+        final String[] parts = input.split(" ");
+        if (parts.length >= 2) {
+            final String semantics = parts[0];
+            for (int i = 1; i < parts.length; ++i) {
+                tagBuilder.add(parts[i]);
+            }
+            return new Group(semantics, tagBuilder.build());
+        }
+        return null;
+    }
+
+    public static Group upgrade(final Element element) {
+        Preconditions.checkArgument("group".equals(element.getName()));
+        Preconditions.checkArgument(Namespace.JINGLE_APPS_GROUPING.equals(element.getNamespace()));
+        final Group group = new Group();
+        group.setAttributes(element.getAttributes());
+        group.setChildren(element.getChildren());
+        return group;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/IbbTransportInfo.java

@@ -0,0 +1,49 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+
+public class IbbTransportInfo extends GenericTransportInfo {
+
+    private IbbTransportInfo(final String name, final String xmlns) {
+        super(name, xmlns);
+    }
+
+    public IbbTransportInfo(final String transportId, final int blockSize) {
+        super("transport", Namespace.JINGLE_TRANSPORTS_IBB);
+        Preconditions.checkNotNull(transportId, "Transport ID can not be null");
+        Preconditions.checkArgument(blockSize > 0, "Block size must be larger than 0");
+        this.setAttribute("block-size", blockSize);
+        this.setAttribute("sid", transportId);
+    }
+
+    public String getTransportId() {
+        return this.getAttribute("sid");
+    }
+
+    public int getBlockSize() {
+        final String blockSize = this.getAttribute("block-size");
+        if (blockSize == null) {
+            return 0;
+        }
+        try {
+            return Integer.parseInt(blockSize);
+        } catch (NumberFormatException e) {
+            return 0;
+        }
+    }
+
+    public static IbbTransportInfo upgrade(final Element element) {
+        Preconditions.checkArgument(
+                "transport".equals(element.getName()), "Name of provided element is not transport");
+        Preconditions.checkArgument(
+                Namespace.JINGLE_TRANSPORTS_IBB.equals(element.getNamespace()),
+                "Element does not match ibb transport namespace");
+        final IbbTransportInfo transportInfo =
+                new IbbTransportInfo("transport", Namespace.JINGLE_TRANSPORTS_IBB);
+        transportInfo.setAttributes(element.getAttributes());
+        transportInfo.setChildren(element.getChildren());
+        return transportInfo;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/IceUdpTransportInfo.java

@@ -0,0 +1,411 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import androidx.annotation.NonNull;
+import com.google.common.base.Joiner;
+import com.google.common.base.MoreObjects;
+import com.google.common.base.Objects;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import eu.siacs.conversations.xmpp.jingle.SessionDescription;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Locale;
+import java.util.Map;
+import java.util.UUID;
+
+public class IceUdpTransportInfo extends GenericTransportInfo {
+
+    public static final IceUdpTransportInfo STUB = new IceUdpTransportInfo();
+
+    public IceUdpTransportInfo() {
+        super("transport", Namespace.JINGLE_TRANSPORT_ICE_UDP);
+    }
+
+    public static IceUdpTransportInfo upgrade(final Element element) {
+        Preconditions.checkArgument(
+                "transport".equals(element.getName()), "Name of provided element is not transport");
+        Preconditions.checkArgument(
+                Namespace.JINGLE_TRANSPORT_ICE_UDP.equals(element.getNamespace()),
+                "Element does not match ice-udp transport namespace");
+        final IceUdpTransportInfo transportInfo = new IceUdpTransportInfo();
+        transportInfo.setAttributes(element.getAttributes());
+        transportInfo.setChildren(element.getChildren());
+        return transportInfo;
+    }
+
+    public static IceUdpTransportInfo of(
+            SessionDescription sessionDescription, SessionDescription.Media media) {
+        final String ufrag = Iterables.getFirst(media.attributes.get("ice-ufrag"), null);
+        final String pwd = Iterables.getFirst(media.attributes.get("ice-pwd"), null);
+        final IceUdpTransportInfo iceUdpTransportInfo = new IceUdpTransportInfo();
+        if (ufrag != null) {
+            iceUdpTransportInfo.setAttribute("ufrag", ufrag);
+        }
+        if (pwd != null) {
+            iceUdpTransportInfo.setAttribute("pwd", pwd);
+        }
+        final Fingerprint fingerprint = Fingerprint.of(sessionDescription, media);
+        if (fingerprint != null) {
+            iceUdpTransportInfo.addChild(fingerprint);
+        }
+        return iceUdpTransportInfo;
+    }
+
+    public static IceUdpTransportInfo of(
+            final Credentials credentials,
+            final Setup setup,
+            final String hash,
+            final String fingerprint) {
+        final IceUdpTransportInfo iceUdpTransportInfo = new IceUdpTransportInfo();
+        iceUdpTransportInfo.addChild(Fingerprint.of(setup, hash, fingerprint));
+        iceUdpTransportInfo.setAttribute("ufrag", credentials.ufrag);
+        iceUdpTransportInfo.setAttribute("pwd", credentials.password);
+        return iceUdpTransportInfo;
+    }
+
+    public Fingerprint getFingerprint() {
+        final Element fingerprint = this.findChild("fingerprint", Namespace.JINGLE_APPS_DTLS);
+        return fingerprint == null ? null : Fingerprint.upgrade(fingerprint);
+    }
+
+    public Credentials getCredentials() {
+        final String ufrag = this.getAttribute("ufrag");
+        final String password = this.getAttribute("pwd");
+        return new Credentials(ufrag, password);
+    }
+
+    public List<Candidate> getCandidates() {
+        final ImmutableList.Builder<Candidate> builder = new ImmutableList.Builder<>();
+        for (final Element child : getChildren()) {
+            if ("candidate".equals(child.getName())) {
+                builder.add(Candidate.upgrade(child));
+            }
+        }
+        return builder.build();
+    }
+
+    public IceUdpTransportInfo cloneWrapper() {
+        final IceUdpTransportInfo transportInfo = new IceUdpTransportInfo();
+        transportInfo.setAttributes(new Hashtable<>(getAttributes()));
+        return transportInfo;
+    }
+
+    public IceUdpTransportInfo modifyCredentials(final Credentials credentials, final Setup setup) {
+        final IceUdpTransportInfo transportInfo = new IceUdpTransportInfo();
+        transportInfo.setAttribute("ufrag", credentials.ufrag);
+        transportInfo.setAttribute("pwd", credentials.password);
+        for (final Element child : getChildren()) {
+            if (child.getName().equals("fingerprint")
+                    && Namespace.JINGLE_APPS_DTLS.equals(child.getNamespace())) {
+                final Fingerprint fingerprint = new Fingerprint();
+                fingerprint.setAttributes(new Hashtable<>(child.getAttributes()));
+                fingerprint.setContent(child.getContent());
+                fingerprint.setAttribute("setup", setup.toString().toLowerCase(Locale.ROOT));
+                transportInfo.addChild(fingerprint);
+            }
+        }
+        return transportInfo;
+    }
+
+    public static class Credentials {
+        public final String ufrag;
+        public final String password;
+
+        public Credentials(String ufrag, String password) {
+            this.ufrag = ufrag;
+            this.password = password;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            Credentials that = (Credentials) o;
+            return Objects.equal(ufrag, that.ufrag) && Objects.equal(password, that.password);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(ufrag, password);
+        }
+
+        @Override
+        @NonNull
+        public String toString() {
+            return MoreObjects.toStringHelper(this)
+                    .add("ufrag", ufrag)
+                    .add("password", password)
+                    .toString();
+        }
+    }
+
+    public static class Candidate extends Element {
+
+        private Candidate() {
+            super("candidate");
+        }
+
+        public static Candidate upgrade(final Element element) {
+            Preconditions.checkArgument("candidate".equals(element.getName()));
+            final Candidate candidate = new Candidate();
+            candidate.setAttributes(element.getAttributes());
+            candidate.setChildren(element.getChildren());
+            return candidate;
+        }
+
+        // https://tools.ietf.org/html/draft-ietf-mmusic-ice-sip-sdp-39#section-5.1
+        public static Candidate fromSdpAttribute(final String attribute, String currentUfrag) {
+            final String[] pair = attribute.split(":", 2);
+            if (pair.length == 2 && "candidate".equals(pair[0])) {
+                final String[] segments = pair[1].split(" ");
+                if (segments.length >= 6) {
+                    final String id = UUID.randomUUID().toString();
+                    final String foundation = segments[0];
+                    final String component = segments[1];
+                    final String transport = segments[2].toLowerCase(Locale.ROOT);
+                    final String priority = segments[3];
+                    final String connectionAddress = segments[4];
+                    final String port = segments[5];
+                    final HashMap<String, String> additional = new HashMap<>();
+                    for (int i = 6; i < segments.length - 1; i = i + 2) {
+                        additional.put(segments[i], segments[i + 1]);
+                    }
+                    final String ufrag = additional.get("ufrag");
+                    if (ufrag != null && !ufrag.equals(currentUfrag)) {
+                        return null;
+                    }
+                    final Candidate candidate = new Candidate();
+                    candidate.setAttribute("component", component);
+                    candidate.setAttribute("foundation", foundation);
+                    candidate.setAttribute("generation", additional.get("generation"));
+                    candidate.setAttribute("rel-addr", additional.get("raddr"));
+                    candidate.setAttribute("rel-port", additional.get("rport"));
+                    candidate.setAttribute("id", id);
+                    candidate.setAttribute("ip", connectionAddress);
+                    candidate.setAttribute("port", port);
+                    candidate.setAttribute("priority", priority);
+                    candidate.setAttribute("protocol", transport);
+                    candidate.setAttribute("type", additional.get("typ"));
+                    return candidate;
+                }
+            }
+            return null;
+        }
+
+        public int getComponent() {
+            return getAttributeAsInt("component");
+        }
+
+        public int getFoundation() {
+            return getAttributeAsInt("foundation");
+        }
+
+        public int getGeneration() {
+            return getAttributeAsInt("generation");
+        }
+
+        public String getId() {
+            return getAttribute("id");
+        }
+
+        public String getIp() {
+            return getAttribute("ip");
+        }
+
+        public int getNetwork() {
+            return getAttributeAsInt("network");
+        }
+
+        public int getPort() {
+            return getAttributeAsInt("port");
+        }
+
+        public int getPriority() {
+            return getAttributeAsInt("priority");
+        }
+
+        public String getProtocol() {
+            return getAttribute("protocol");
+        }
+
+        public String getRelAddr() {
+            return getAttribute("rel-addr");
+        }
+
+        public int getRelPort() {
+            return getAttributeAsInt("rel-port");
+        }
+
+        public String getType() { // TODO might be converted to enum
+            return getAttribute("type");
+        }
+
+        private int getAttributeAsInt(final String name) {
+            final String value = this.getAttribute(name);
+            if (value == null) {
+                return 0;
+            }
+            try {
+                return Integer.parseInt(value);
+            } catch (NumberFormatException e) {
+                return 0;
+            }
+        }
+
+        public String toSdpAttribute(final String ufrag) {
+            final String foundation = this.getAttribute("foundation");
+            checkNotNullNoWhitespace(foundation, "foundation");
+            final String component = this.getAttribute("component");
+            checkNotNullNoWhitespace(component, "component");
+            final String protocol = this.getAttribute("protocol");
+            checkNotNullNoWhitespace(protocol, "protocol");
+            final String transport = protocol.toLowerCase(Locale.ROOT);
+            if (!"udp".equals(transport)) {
+                throw new IllegalArgumentException(
+                        String.format("'%s' is not a supported protocol", transport));
+            }
+            final String priority = this.getAttribute("priority");
+            checkNotNullNoWhitespace(priority, "priority");
+            final String connectionAddress = this.getAttribute("ip");
+            checkNotNullNoWhitespace(connectionAddress, "ip");
+            final String port = this.getAttribute("port");
+            checkNotNullNoWhitespace(port, "port");
+            final Map<String, String> additionalParameter = new LinkedHashMap<>();
+            final String relAddr = this.getAttribute("rel-addr");
+            final String type = this.getAttribute("type");
+            if (type != null) {
+                additionalParameter.put("typ", type);
+            }
+            if (relAddr != null) {
+                additionalParameter.put("raddr", relAddr);
+            }
+            final String relPort = this.getAttribute("rel-port");
+            if (relPort != null) {
+                additionalParameter.put("rport", relPort);
+            }
+            final String generation = this.getAttribute("generation");
+            if (generation != null) {
+                additionalParameter.put("generation", generation);
+            }
+            if (ufrag != null) {
+                additionalParameter.put("ufrag", ufrag);
+            }
+            final String parametersString =
+                    Joiner.on(' ')
+                            .join(
+                                    Collections2.transform(
+                                            additionalParameter.entrySet(),
+                                            input ->
+                                                    String.format(
+                                                            "%s %s",
+                                                            input.getKey(), input.getValue())));
+            return String.format(
+                    "candidate:%s %s %s %s %s %s %s",
+                    foundation,
+                    component,
+                    transport,
+                    priority,
+                    connectionAddress,
+                    port,
+                    parametersString);
+        }
+    }
+
+    private static void checkNotNullNoWhitespace(final String value, final String name) {
+        if (Strings.isNullOrEmpty(value)) {
+            throw new IllegalArgumentException(
+                    String.format("Parameter %s is missing or empty", name));
+        }
+        SessionDescription.checkNoWhitespace(
+                value, String.format("Parameter %s contains white spaces", name));
+    }
+
+    public static class Fingerprint extends Element {
+
+        private Fingerprint() {
+            super("fingerprint", Namespace.JINGLE_APPS_DTLS);
+        }
+
+        public static Fingerprint upgrade(final Element element) {
+            Preconditions.checkArgument("fingerprint".equals(element.getName()));
+            Preconditions.checkArgument(Namespace.JINGLE_APPS_DTLS.equals(element.getNamespace()));
+            final Fingerprint fingerprint = new Fingerprint();
+            fingerprint.setAttributes(element.getAttributes());
+            fingerprint.setContent(element.getContent());
+            return fingerprint;
+        }
+
+        private static Fingerprint of(ArrayListMultimap<String, String> attributes) {
+            final String fingerprint = Iterables.getFirst(attributes.get("fingerprint"), null);
+            final String setup = Iterables.getFirst(attributes.get("setup"), null);
+            if (setup != null && fingerprint != null) {
+                final String[] fingerprintParts = fingerprint.split(" ", 2);
+                if (fingerprintParts.length == 2) {
+                    final String hash = fingerprintParts[0];
+                    final String actualFingerprint = fingerprintParts[1];
+                    final Fingerprint element = new Fingerprint();
+                    element.setAttribute("hash", hash);
+                    element.setAttribute("setup", setup);
+                    element.setContent(actualFingerprint);
+                    return element;
+                }
+            }
+            return null;
+        }
+
+        public static Fingerprint of(
+                final SessionDescription sessionDescription, final SessionDescription.Media media) {
+            final Fingerprint fingerprint = of(media.attributes);
+            return fingerprint == null ? of(sessionDescription.attributes) : fingerprint;
+        }
+
+        private static Fingerprint of(final Setup setup, final String hash, final String content) {
+            final Fingerprint fingerprint = new Fingerprint();
+            fingerprint.setContent(content);
+            fingerprint.setAttribute("hash", hash);
+            fingerprint.setAttribute("setup", setup.toString().toLowerCase(Locale.ROOT));
+            return fingerprint;
+        }
+
+        public String getHash() {
+            return this.getAttribute("hash");
+        }
+
+        public Setup getSetup() {
+            final String setup = this.getAttribute("setup");
+            return setup == null ? null : Setup.of(setup);
+        }
+    }
+
+    public enum Setup {
+        ACTPASS,
+        PASSIVE,
+        ACTIVE;
+
+        public static Setup of(String setup) {
+            try {
+                return valueOf(setup.toUpperCase(Locale.ROOT));
+            } catch (IllegalArgumentException e) {
+                return null;
+            }
+        }
+
+        public Setup flip() {
+            if (this == PASSIVE) {
+                return ACTIVE;
+            }
+            if (this == ACTIVE) {
+                return PASSIVE;
+            }
+            throw new IllegalStateException(this.name() + " can not be flipped");
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/JinglePacket.java

@@ -0,0 +1,162 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import androidx.annotation.NonNull;
+import com.google.common.base.CaseFormat;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableMap;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import im.conversations.android.xmpp.model.stanza.Iq;
+import java.util.Map;
+import org.jxmpp.jid.Jid;
+
+public class JinglePacket extends Iq {
+
+    private JinglePacket() {
+        super();
+    }
+
+    public JinglePacket(final Action action, final String sessionId) {
+        super(Iq.Type.SET);
+        final Element jingle = addChild("jingle", Namespace.JINGLE);
+        jingle.setAttribute("sid", sessionId);
+        jingle.setAttribute("action", action.toString());
+    }
+
+    public static JinglePacket upgrade(final Iq iqPacket) {
+        Preconditions.checkArgument(iqPacket.hasChild("jingle", Namespace.JINGLE));
+        Preconditions.checkArgument(iqPacket.getType() == Iq.Type.SET);
+        final JinglePacket jinglePacket = new JinglePacket();
+        jinglePacket.setAttributes(iqPacket.getAttributes());
+        jinglePacket.setChildren(iqPacket.getChildren());
+        return jinglePacket;
+    }
+
+    // TODO deprecate this somehow and make file transfer fail if there are multiple (or something)
+    public Content getJingleContent() {
+        final Element content = getJingleChild("content");
+        return content == null ? null : Content.upgrade(content);
+    }
+
+    public Group getGroup() {
+        final Element jingle = findChild("jingle", Namespace.JINGLE);
+        final Element group = jingle.findChild("group", Namespace.JINGLE_APPS_GROUPING);
+        return group == null ? null : Group.upgrade(group);
+    }
+
+    public void addGroup(final Group group) {
+        this.addJingleChild(group);
+    }
+
+    public Map<String, Content> getJingleContents() {
+        final Element jingle = findChild("jingle", Namespace.JINGLE);
+        ImmutableMap.Builder<String, Content> builder = new ImmutableMap.Builder<>();
+        for (final Element child : jingle.getChildren()) {
+            if ("content".equals(child.getName())) {
+                final Content content = Content.upgrade(child);
+                builder.put(content.getContentName(), content);
+            }
+        }
+        return builder.build();
+    }
+
+    public void addJingleContent(final Content content) { // take content interface
+        addJingleChild(content);
+    }
+
+    public ReasonWrapper getReason() {
+        final Element reasonElement = getJingleChild("reason");
+        if (reasonElement == null) {
+            return new ReasonWrapper(Reason.UNKNOWN, null);
+        }
+        String text = null;
+        Reason reason = Reason.UNKNOWN;
+        for (Element child : reasonElement.getChildren()) {
+            if ("text".equals(child.getName())) {
+                text = child.getContent();
+            } else {
+                reason = Reason.of(child.getName());
+            }
+        }
+        return new ReasonWrapper(reason, text);
+    }
+
+    public void setReason(final Reason reason, final String text) {
+        final Element jingle = findChild("jingle", Namespace.JINGLE);
+        final Element reasonElement = jingle.addChild("reason");
+        reasonElement.addChild(reason.toString());
+        if (!Strings.isNullOrEmpty(text)) {
+            reasonElement.addChild("text").setContent(text);
+        }
+    }
+
+    // RECOMMENDED for session-initiate, NOT RECOMMENDED otherwise
+    public void setInitiator(final Jid initiator) {
+        Preconditions.checkArgument(initiator.isEntityFullJid(), "initiator should be a full JID");
+        findChild("jingle", Namespace.JINGLE).setAttribute("initiator", initiator);
+    }
+
+    // RECOMMENDED for session-accept, NOT RECOMMENDED otherwise
+    public void setResponder(Jid responder) {
+        Preconditions.checkArgument(responder.isEntityFullJid(), "responder should be a full JID");
+        findChild("jingle", Namespace.JINGLE).setAttribute("responder", responder);
+    }
+
+    public Element getJingleChild(final String name) {
+        final Element jingle = findChild("jingle", Namespace.JINGLE);
+        return jingle == null ? null : jingle.findChild(name);
+    }
+
+    public void addJingleChild(final Element child) {
+        final Element jingle = findChild("jingle", Namespace.JINGLE);
+        jingle.addChild(child);
+    }
+
+    public String getSessionId() {
+        return findChild("jingle", Namespace.JINGLE).getAttribute("sid");
+    }
+
+    public Action getAction() {
+        return Action.of(findChild("jingle", Namespace.JINGLE).getAttribute("action"));
+    }
+
+    public enum Action {
+        CONTENT_ACCEPT,
+        CONTENT_ADD,
+        CONTENT_MODIFY,
+        CONTENT_REJECT,
+        CONTENT_REMOVE,
+        DESCRIPTION_INFO,
+        SECURITY_INFO,
+        SESSION_ACCEPT,
+        SESSION_INFO,
+        SESSION_INITIATE,
+        SESSION_TERMINATE,
+        TRANSPORT_ACCEPT,
+        TRANSPORT_INFO,
+        TRANSPORT_REJECT,
+        TRANSPORT_REPLACE;
+
+        public static Action of(final String value) {
+            // TODO handle invalid
+            return Action.valueOf(CaseFormat.LOWER_HYPHEN.to(CaseFormat.UPPER_UNDERSCORE, value));
+        }
+
+        @Override
+        @NonNull
+        public String toString() {
+            return CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_HYPHEN, super.toString());
+        }
+    }
+
+    public static class ReasonWrapper {
+        public final Reason reason;
+        public final String text;
+
+        public ReasonWrapper(Reason reason, String text) {
+            this.reason = reason;
+            this.text = text;
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/OmemoVerifiedIceUdpTransportInfo.java

@@ -0,0 +1,27 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import im.conversations.android.xml.Namespace;
+
+public class OmemoVerifiedIceUdpTransportInfo extends IceUdpTransportInfo {
+
+    public void ensureNoPlaintextFingerprint() {
+        if (this.findChild("fingerprint", Namespace.JINGLE_APPS_DTLS) != null) {
+            throw new IllegalStateException(
+                    "OmemoVerifiedIceUdpTransportInfo contains plaintext fingerprint");
+        }
+    }
+
+    public static IceUdpTransportInfo upgrade(final IceUdpTransportInfo transportInfo) {
+        if (transportInfo.hasChild("fingerprint", Namespace.JINGLE_APPS_DTLS)) {
+            return transportInfo;
+        }
+        if (transportInfo.hasChild("fingerprint", Namespace.OMEMO_DTLS_SRTP_VERIFICATION)) {
+            final OmemoVerifiedIceUdpTransportInfo omemoVerifiedIceUdpTransportInfo =
+                    new OmemoVerifiedIceUdpTransportInfo();
+            omemoVerifiedIceUdpTransportInfo.setAttributes(transportInfo.getAttributes());
+            omemoVerifiedIceUdpTransportInfo.setChildren(transportInfo.getChildren());
+            return omemoVerifiedIceUdpTransportInfo;
+        }
+        return transportInfo;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/Reason.java

@@ -0,0 +1,65 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import androidx.annotation.NonNull;
+import com.google.common.base.CaseFormat;
+import com.google.common.base.Throwables;
+import eu.siacs.conversations.xmpp.jingle.RtpContentMap;
+import im.conversations.android.axolotl.AxolotlEncryptionException;
+
+public enum Reason {
+    ALTERNATIVE_SESSION,
+    BUSY,
+    CANCEL,
+    CONNECTIVITY_ERROR,
+    DECLINE,
+    EXPIRED,
+    FAILED_APPLICATION,
+    FAILED_TRANSPORT,
+    GENERAL_ERROR,
+    GONE,
+    INCOMPATIBLE_PARAMETERS,
+    MEDIA_ERROR,
+    SECURITY_ERROR,
+    SUCCESS,
+    TIMEOUT,
+    UNSUPPORTED_APPLICATIONS,
+    UNSUPPORTED_TRANSPORTS,
+    UNKNOWN;
+
+    public static Reason of(final String value) {
+        try {
+            return Reason.valueOf(CaseFormat.LOWER_HYPHEN.to(CaseFormat.UPPER_UNDERSCORE, value));
+        } catch (Exception e) {
+            return UNKNOWN;
+        }
+    }
+
+    @Override
+    @NonNull
+    public String toString() {
+        return CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_HYPHEN, super.toString());
+    }
+
+    public static Reason of(final RuntimeException e) {
+        if (e instanceof SecurityException) {
+            return SECURITY_ERROR;
+        } else if (e instanceof RtpContentMap.UnsupportedTransportException) {
+            return UNSUPPORTED_TRANSPORTS;
+        } else if (e instanceof RtpContentMap.UnsupportedApplicationException) {
+            return UNSUPPORTED_APPLICATIONS;
+        } else {
+            return FAILED_APPLICATION;
+        }
+    }
+
+    public static Reason ofThrowable(final Throwable throwable) {
+        final Throwable root = Throwables.getRootCause(throwable);
+        if (root instanceof RuntimeException) {
+            return of((RuntimeException) root);
+        }
+        if (root instanceof AxolotlEncryptionException) {
+            return SECURITY_ERROR;
+        }
+        return FAILED_APPLICATION;
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/RtpDescription.java

@@ -0,0 +1,658 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import android.util.Pair;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import com.google.common.collect.ArrayListMultimap;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Sets;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import eu.siacs.conversations.xmpp.jingle.SessionDescription;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.Collection;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class RtpDescription extends GenericDescription {
+
+    private RtpDescription(final String media) {
+        super("description", Namespace.JINGLE_APPS_RTP);
+        this.setAttribute("media", media);
+    }
+
+    private RtpDescription() {
+        super("description", Namespace.JINGLE_APPS_RTP);
+    }
+
+    public static RtpDescription stub(final Media media) {
+        return new RtpDescription(media.toString());
+    }
+
+    public Media getMedia() {
+        return Media.of(this.getAttribute("media"));
+    }
+
+    public List<PayloadType> getPayloadTypes() {
+        final ImmutableList.Builder<PayloadType> builder = new ImmutableList.Builder<>();
+        for (Element child : getChildren()) {
+            if ("payload-type".equals(child.getName())) {
+                builder.add(PayloadType.of(child));
+            }
+        }
+        return builder.build();
+    }
+
+    public List<FeedbackNegotiation> getFeedbackNegotiations() {
+        return FeedbackNegotiation.fromChildren(this.getChildren());
+    }
+
+    public List<FeedbackNegotiationTrrInt> feedbackNegotiationTrrInts() {
+        return FeedbackNegotiationTrrInt.fromChildren(this.getChildren());
+    }
+
+    public List<RtpHeaderExtension> getHeaderExtensions() {
+        final ImmutableList.Builder<RtpHeaderExtension> builder = new ImmutableList.Builder<>();
+        for (final Element child : getChildren()) {
+            if ("rtp-hdrext".equals(child.getName())
+                    && Namespace.JINGLE_RTP_HEADER_EXTENSIONS.equals(child.getNamespace())) {
+                builder.add(RtpHeaderExtension.upgrade(child));
+            }
+        }
+        return builder.build();
+    }
+
+    public List<Source> getSources() {
+        final ImmutableList.Builder<Source> builder = new ImmutableList.Builder<>();
+        for (final Element child : this.children) {
+            if ("source".equals(child.getName())
+                    && Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES.equals(
+                            child.getNamespace())) {
+                builder.add(Source.upgrade(child));
+            }
+        }
+        return builder.build();
+    }
+
+    public List<SourceGroup> getSourceGroups() {
+        final ImmutableList.Builder<SourceGroup> builder = new ImmutableList.Builder<>();
+        for (final Element child : this.children) {
+            if ("ssrc-group".equals(child.getName())
+                    && Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES.equals(
+                            child.getNamespace())) {
+                builder.add(SourceGroup.upgrade(child));
+            }
+        }
+        return builder.build();
+    }
+
+    public static RtpDescription upgrade(final Element element) {
+        Preconditions.checkArgument(
+                "description".equals(element.getName()),
+                "Name of provided element is not description");
+        Preconditions.checkArgument(
+                Namespace.JINGLE_APPS_RTP.equals(element.getNamespace()),
+                "Element does not match the jingle rtp namespace");
+        final RtpDescription description = new RtpDescription();
+        description.setAttributes(element.getAttributes());
+        description.setChildren(element.getChildren());
+        return description;
+    }
+
+    public static class FeedbackNegotiation extends Element {
+        private FeedbackNegotiation() {
+            super("rtcp-fb", Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION);
+        }
+
+        public FeedbackNegotiation(String type, String subType) {
+            super("rtcp-fb", Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION);
+            this.setAttribute("type", type);
+            if (subType != null) {
+                this.setAttribute("subtype", subType);
+            }
+        }
+
+        public String getType() {
+            return this.getAttribute("type");
+        }
+
+        public String getSubType() {
+            return this.getAttribute("subtype");
+        }
+
+        private static FeedbackNegotiation upgrade(final Element element) {
+            Preconditions.checkArgument("rtcp-fb".equals(element.getName()));
+            Preconditions.checkArgument(
+                    Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION.equals(element.getNamespace()));
+            final FeedbackNegotiation feedback = new FeedbackNegotiation();
+            feedback.setAttributes(element.getAttributes());
+            feedback.setChildren(element.getChildren());
+            return feedback;
+        }
+
+        public static List<FeedbackNegotiation> fromChildren(final List<Element> children) {
+            ImmutableList.Builder<FeedbackNegotiation> builder = new ImmutableList.Builder<>();
+            for (final Element child : children) {
+                if ("rtcp-fb".equals(child.getName())
+                        && Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION.equals(child.getNamespace())) {
+                    builder.add(upgrade(child));
+                }
+            }
+            return builder.build();
+        }
+    }
+
+    public static class FeedbackNegotiationTrrInt extends Element {
+
+        private FeedbackNegotiationTrrInt(int value) {
+            super("rtcp-fb-trr-int", Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION);
+            this.setAttribute("value", value);
+        }
+
+        private FeedbackNegotiationTrrInt() {
+            super("rtcp-fb-trr-int", Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION);
+        }
+
+        public int getValue() {
+            final String value = getAttribute("value");
+            return Integer.parseInt(value);
+        }
+
+        private static FeedbackNegotiationTrrInt upgrade(final Element element) {
+            Preconditions.checkArgument("rtcp-fb-trr-int".equals(element.getName()));
+            Preconditions.checkArgument(
+                    Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION.equals(element.getNamespace()));
+            final FeedbackNegotiationTrrInt trr = new FeedbackNegotiationTrrInt();
+            trr.setAttributes(element.getAttributes());
+            trr.setChildren(element.getChildren());
+            return trr;
+        }
+
+        public static List<FeedbackNegotiationTrrInt> fromChildren(final List<Element> children) {
+            ImmutableList.Builder<FeedbackNegotiationTrrInt> builder =
+                    new ImmutableList.Builder<>();
+            for (final Element child : children) {
+                if ("rtcp-fb-trr-int".equals(child.getName())
+                        && Namespace.JINGLE_RTP_FEEDBACK_NEGOTIATION.equals(child.getNamespace())) {
+                    builder.add(upgrade(child));
+                }
+            }
+            return builder.build();
+        }
+    }
+
+    // XEP-0294: Jingle RTP Header Extensions Negotiation
+    // maps to `extmap:$id $uri`
+    public static class RtpHeaderExtension extends Element {
+
+        private RtpHeaderExtension() {
+            super("rtp-hdrext", Namespace.JINGLE_RTP_HEADER_EXTENSIONS);
+        }
+
+        public RtpHeaderExtension(String id, String uri) {
+            super("rtp-hdrext", Namespace.JINGLE_RTP_HEADER_EXTENSIONS);
+            this.setAttribute("id", id);
+            this.setAttribute("uri", uri);
+        }
+
+        public String getId() {
+            return this.getAttribute("id");
+        }
+
+        public String getUri() {
+            return this.getAttribute("uri");
+        }
+
+        public static RtpHeaderExtension upgrade(final Element element) {
+            Preconditions.checkArgument("rtp-hdrext".equals(element.getName()));
+            Preconditions.checkArgument(
+                    Namespace.JINGLE_RTP_HEADER_EXTENSIONS.equals(element.getNamespace()));
+            final RtpHeaderExtension extension = new RtpHeaderExtension();
+            extension.setAttributes(element.getAttributes());
+            extension.setChildren(element.getChildren());
+            return extension;
+        }
+
+        public static RtpHeaderExtension ofSdpString(final String sdp) {
+            final String[] pair = sdp.split(" ", 2);
+            if (pair.length == 2) {
+                final String id = pair[0];
+                final String uri = pair[1];
+                return new RtpHeaderExtension(id, uri);
+            } else {
+                return null;
+            }
+        }
+    }
+
+    // maps to `rtpmap:$id $name/$clockrate/$channels`
+    public static class PayloadType extends Element {
+
+        private PayloadType() {
+            super("payload-type", Namespace.JINGLE_APPS_RTP);
+        }
+
+        public PayloadType(String id, String name, int clockRate, int channels) {
+            super("payload-type", Namespace.JINGLE_APPS_RTP);
+            this.setAttribute("id", id);
+            this.setAttribute("name", name);
+            this.setAttribute("clockrate", clockRate);
+            if (channels != 1) {
+                this.setAttribute("channels", channels);
+            }
+        }
+
+        public String toSdpAttribute() {
+            final int channels = getChannels();
+            final String name = getPayloadTypeName();
+            Preconditions.checkArgument(name != null, "Payload-type name must not be empty");
+            SessionDescription.checkNoWhitespace(
+                    name, "payload-type name must not contain whitespaces");
+            return getId()
+                    + " "
+                    + name
+                    + "/"
+                    + getClockRate()
+                    + (channels == 1 ? "" : "/" + channels);
+        }
+
+        public int getIntId() {
+            final String id = this.getAttribute("id");
+            return id == null ? 0 : SessionDescription.ignorantIntParser(id);
+        }
+
+        public String getId() {
+            return this.getAttribute("id");
+        }
+
+        public String getPayloadTypeName() {
+            return this.getAttribute("name");
+        }
+
+        public int getClockRate() {
+            final String clockRate = this.getAttribute("clockrate");
+            if (clockRate == null) {
+                return 0;
+            }
+            try {
+                return Integer.parseInt(clockRate);
+            } catch (NumberFormatException e) {
+                return 0;
+            }
+        }
+
+        public int getChannels() {
+            final String channels = this.getAttribute("channels");
+            if (channels == null) {
+                return 1; // The number of channels; if omitted, it MUST be assumed to contain one
+                // channel
+            }
+            try {
+                return Integer.parseInt(channels);
+            } catch (NumberFormatException e) {
+                return 1;
+            }
+        }
+
+        public List<Parameter> getParameters() {
+            final ImmutableList.Builder<Parameter> builder = new ImmutableList.Builder<>();
+            for (Element child : getChildren()) {
+                if ("parameter".equals(child.getName())) {
+                    builder.add(Parameter.of(child));
+                }
+            }
+            return builder.build();
+        }
+
+        public List<FeedbackNegotiation> getFeedbackNegotiations() {
+            return FeedbackNegotiation.fromChildren(this.getChildren());
+        }
+
+        public List<FeedbackNegotiationTrrInt> feedbackNegotiationTrrInts() {
+            return FeedbackNegotiationTrrInt.fromChildren(this.getChildren());
+        }
+
+        public static PayloadType of(final Element element) {
+            Preconditions.checkArgument(
+                    "payload-type".equals(element.getName()),
+                    "element name must be called payload-type");
+            PayloadType payloadType = new PayloadType();
+            payloadType.setAttributes(element.getAttributes());
+            payloadType.setChildren(element.getChildren());
+            return payloadType;
+        }
+
+        public static PayloadType ofSdpString(final String sdp) {
+            final String[] pair = sdp.split(" ", 2);
+            if (pair.length == 2) {
+                final String id = pair[0];
+                final String[] parts = pair[1].split("/");
+                if (parts.length >= 2) {
+                    final String name = parts[0];
+                    final int clockRate = SessionDescription.ignorantIntParser(parts[1]);
+                    final int channels;
+                    if (parts.length >= 3) {
+                        channels = SessionDescription.ignorantIntParser(parts[2]);
+                    } else {
+                        channels = 1;
+                    }
+                    return new PayloadType(id, name, clockRate, channels);
+                }
+            }
+            return null;
+        }
+
+        public void addChildren(final List<Element> children) {
+            if (children != null) {
+                this.children.addAll(children);
+            }
+        }
+
+        public void addParameters(List<Parameter> parameters) {
+            if (parameters != null) {
+                this.children.addAll(parameters);
+            }
+        }
+    }
+
+    // map to `fmtp $id key=value;key=value
+    // where id is the id of the parent payload-type
+    public static class Parameter extends Element {
+
+        private Parameter() {
+            super("parameter", Namespace.JINGLE_APPS_RTP);
+        }
+
+        public Parameter(String name, String value) {
+            super("parameter", Namespace.JINGLE_APPS_RTP);
+            this.setAttribute("name", name);
+            this.setAttribute("value", value);
+        }
+
+        public String getParameterName() {
+            return this.getAttribute("name");
+        }
+
+        public String getParameterValue() {
+            return this.getAttribute("value");
+        }
+
+        public static Parameter of(final Element element) {
+            Preconditions.checkArgument(
+                    "parameter".equals(element.getName()), "element name must be called parameter");
+            Parameter parameter = new Parameter();
+            parameter.setAttributes(element.getAttributes());
+            parameter.setChildren(element.getChildren());
+            return parameter;
+        }
+
+        public static String toSdpString(final String id, List<Parameter> parameters) {
+            final StringBuilder stringBuilder = new StringBuilder();
+            stringBuilder.append(id).append(' ');
+            for (int i = 0; i < parameters.size(); ++i) {
+                final Parameter p = parameters.get(i);
+                final String name = p.getParameterName();
+                Preconditions.checkArgument(
+                        name != null, String.format("parameter for %s must have a name", id));
+                SessionDescription.checkNoWhitespace(
+                        name,
+                        String.format("parameter names for %s must not contain whitespaces", id));
+
+                final String value = p.getParameterValue();
+                Preconditions.checkArgument(
+                        value != null, String.format("parameter for %s must have a value", id));
+                SessionDescription.checkNoWhitespace(
+                        value,
+                        String.format("parameter values for %s must not contain whitespaces", id));
+
+                stringBuilder.append(name).append('=').append(value);
+                if (i != parameters.size() - 1) {
+                    stringBuilder.append(';');
+                }
+            }
+            return stringBuilder.toString();
+        }
+
+        public static String toSdpString(final String id, final Parameter parameter) {
+            final String name = parameter.getParameterName();
+            final String value = parameter.getParameterValue();
+            Preconditions.checkArgument(
+                    value != null, String.format("parameter for %s must have a value", id));
+            SessionDescription.checkNoWhitespace(
+                    value,
+                    String.format("parameter values for %s must not contain whitespaces", id));
+            if (Strings.isNullOrEmpty(name)) {
+                return String.format("%s %s", id, value);
+            } else {
+                return String.format("%s %s=%s", id, name, value);
+            }
+        }
+
+        static Pair<String, List<Parameter>> ofSdpString(final String sdp) {
+            final String[] pair = sdp.split(" ");
+            if (pair.length == 2) {
+                final String id = pair[0];
+                final ImmutableList.Builder<Parameter> builder = new ImmutableList.Builder<>();
+                for (final String parameter : pair[1].split(";")) {
+                    final String[] parts = parameter.split("=", 2);
+                    if (parts.length == 2) {
+                        builder.add(new Parameter(parts[0], parts[1]));
+                    }
+                }
+                return new Pair<>(id, builder.build());
+            } else {
+                return null;
+            }
+        }
+    }
+
+    // XEP-0339: Source-Specific Media Attributes in Jingle
+    // maps to `a=ssrc:<ssrc-id> <attribute>:<value>`
+    public static class Source extends Element {
+
+        private Source() {
+            super("source", Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES);
+        }
+
+        public Source(String ssrcId, Collection<Parameter> parameters) {
+            super("source", Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES);
+            this.setAttribute("ssrc", ssrcId);
+            for (Parameter parameter : parameters) {
+                this.addChild(parameter);
+            }
+        }
+
+        public String getSsrcId() {
+            return this.getAttribute("ssrc");
+        }
+
+        public List<Parameter> getParameters() {
+            ImmutableList.Builder<Parameter> builder = new ImmutableList.Builder<>();
+            for (Element child : this.children) {
+                if ("parameter".equals(child.getName())) {
+                    builder.add(Parameter.upgrade(child));
+                }
+            }
+            return builder.build();
+        }
+
+        public static Source upgrade(final Element element) {
+            Preconditions.checkArgument("source".equals(element.getName()));
+            Preconditions.checkArgument(
+                    Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES.equals(
+                            element.getNamespace()));
+            final Source source = new Source();
+            source.setChildren(element.getChildren());
+            source.setAttributes(element.getAttributes());
+            return source;
+        }
+
+        public static class Parameter extends Element {
+
+            public String getParameterName() {
+                return this.getAttribute("name");
+            }
+
+            public String getParameterValue() {
+                return this.getAttribute("value");
+            }
+
+            private Parameter() {
+                super("parameter");
+            }
+
+            public Parameter(final String attribute, final String value) {
+                super("parameter");
+                this.setAttribute("name", attribute);
+                if (value != null) {
+                    this.setAttribute("value", value);
+                }
+            }
+
+            public static Parameter upgrade(final Element element) {
+                Preconditions.checkArgument("parameter".equals(element.getName()));
+                Parameter parameter = new Parameter();
+                parameter.setAttributes(element.getAttributes());
+                parameter.setChildren(element.getChildren());
+                return parameter;
+            }
+        }
+    }
+
+    public static class SourceGroup extends Element {
+
+        public SourceGroup(final String semantics, List<String> ssrcs) {
+            this();
+            this.setAttribute("semantics", semantics);
+            for (String ssrc : ssrcs) {
+                this.addChild("source").setAttribute("ssrc", ssrc);
+            }
+        }
+
+        private SourceGroup() {
+            super("ssrc-group", Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES);
+        }
+
+        public String getSemantics() {
+            return this.getAttribute("semantics");
+        }
+
+        public List<String> getSsrcs() {
+            ImmutableList.Builder<String> builder = new ImmutableList.Builder<>();
+            for (Element child : this.children) {
+                if ("source".equals(child.getName())) {
+                    final String ssrc = child.getAttribute("ssrc");
+                    if (ssrc != null) {
+                        builder.add(ssrc);
+                    }
+                }
+            }
+            return builder.build();
+        }
+
+        public static SourceGroup upgrade(final Element element) {
+            Preconditions.checkArgument("ssrc-group".equals(element.getName()));
+            Preconditions.checkArgument(
+                    Namespace.JINGLE_RTP_SOURCE_SPECIFIC_MEDIA_ATTRIBUTES.equals(
+                            element.getNamespace()));
+            final SourceGroup group = new SourceGroup();
+            group.setChildren(element.getChildren());
+            group.setAttributes(element.getAttributes());
+            return group;
+        }
+    }
+
+    public static RtpDescription of(
+            final SessionDescription sessionDescription, final SessionDescription.Media media) {
+        final RtpDescription rtpDescription = new RtpDescription(media.media);
+        final Map<String, List<Parameter>> parameterMap = new HashMap<>();
+        final ArrayListMultimap<String, Element> feedbackNegotiationMap =
+                ArrayListMultimap.create();
+        final ArrayListMultimap<String, Source.Parameter> sourceParameterMap =
+                ArrayListMultimap.create();
+        final Set<String> attributes =
+                Sets.newHashSet(
+                        Iterables.concat(
+                                sessionDescription.attributes.keySet(), media.attributes.keySet()));
+        for (final String rtcpFb : media.attributes.get("rtcp-fb")) {
+            final String[] parts = rtcpFb.split(" ");
+            if (parts.length >= 2) {
+                final String id = parts[0];
+                final String type = parts[1];
+                final String subType = parts.length >= 3 ? parts[2] : null;
+                if ("trr-int".equals(type)) {
+                    if (subType != null) {
+                        feedbackNegotiationMap.put(
+                                id,
+                                new FeedbackNegotiationTrrInt(
+                                        SessionDescription.ignorantIntParser(subType)));
+                    }
+                } else {
+                    feedbackNegotiationMap.put(id, new FeedbackNegotiation(type, subType));
+                }
+            }
+        }
+        for (final String ssrc : media.attributes.get(("ssrc"))) {
+            final String[] parts = ssrc.split(" ", 2);
+            if (parts.length == 2) {
+                final String id = parts[0];
+                final String[] subParts = parts[1].split(":", 2);
+                final String attribute = subParts[0];
+                final String value = subParts.length == 2 ? subParts[1] : null;
+                sourceParameterMap.put(id, new Source.Parameter(attribute, value));
+            }
+        }
+        for (final String fmtp : media.attributes.get("fmtp")) {
+            final Pair<String, List<Parameter>> pair = Parameter.ofSdpString(fmtp);
+            if (pair != null) {
+                parameterMap.put(pair.first, pair.second);
+            }
+        }
+        rtpDescription.addChildren(feedbackNegotiationMap.get("*"));
+        for (final String rtpmap : media.attributes.get("rtpmap")) {
+            final PayloadType payloadType = PayloadType.ofSdpString(rtpmap);
+            if (payloadType != null) {
+                payloadType.addParameters(parameterMap.get(payloadType.getId()));
+                payloadType.addChildren(feedbackNegotiationMap.get(payloadType.getId()));
+                rtpDescription.addChild(payloadType);
+            }
+        }
+        for (final String extmap : media.attributes.get("extmap")) {
+            final RtpHeaderExtension extension = RtpHeaderExtension.ofSdpString(extmap);
+            if (extension != null) {
+                rtpDescription.addChild(extension);
+            }
+        }
+        if (attributes.contains("extmap-allow-mixed")) {
+            rtpDescription.addChild("extmap-allow-mixed", Namespace.JINGLE_RTP_HEADER_EXTENSIONS);
+        }
+        for (final String ssrcGroup : media.attributes.get("ssrc-group")) {
+            final String[] parts = ssrcGroup.split(" ");
+            if (parts.length >= 2) {
+                ImmutableList.Builder<String> builder = new ImmutableList.Builder<>();
+                final String semantics = parts[0];
+                for (int i = 1; i < parts.length; ++i) {
+                    builder.add(parts[i]);
+                }
+                rtpDescription.addChild(new SourceGroup(semantics, builder.build()));
+            }
+        }
+        for (Map.Entry<String, Collection<Source.Parameter>> source :
+                sourceParameterMap.asMap().entrySet()) {
+            rtpDescription.addChild(new Source(source.getKey(), source.getValue()));
+        }
+        if (media.attributes.containsKey("rtcp-mux")) {
+            rtpDescription.addChild("rtcp-mux");
+        }
+        return rtpDescription;
+    }
+
+    private void addChildren(List<Element> elements) {
+        if (elements != null) {
+            this.children.addAll(elements);
+        }
+    }
+}

app/src/main/java/eu/siacs/conversations/xmpp/jingle/stanzas/S5BTransportInfo.java

@@ -0,0 +1,53 @@
+package eu.siacs.conversations.xmpp.jingle.stanzas;
+
+import com.google.common.base.Preconditions;
+import eu.siacs.conversations.xmpp.jingle.JingleCandidate;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.Collection;
+import java.util.List;
+
+public class S5BTransportInfo extends GenericTransportInfo {
+
+    private S5BTransportInfo(final String name, final String xmlns) {
+        super(name, xmlns);
+    }
+
+    public String getTransportId() {
+        return this.getAttribute("sid");
+    }
+
+    public S5BTransportInfo(
+            final String transportId, final Collection<JingleCandidate> candidates) {
+        super("transport", Namespace.JINGLE_TRANSPORTS_S5B);
+        Preconditions.checkNotNull(transportId, "transport id must not be null");
+        for (JingleCandidate candidate : candidates) {
+            this.addChild(candidate.toElement());
+        }
+        this.setAttribute("sid", transportId);
+    }
+
+    public S5BTransportInfo(final String transportId, final Element child) {
+        super("transport", Namespace.JINGLE_TRANSPORTS_S5B);
+        Preconditions.checkNotNull(transportId, "transport id must not be null");
+        this.addChild(child);
+        this.setAttribute("sid", transportId);
+    }
+
+    public List<JingleCandidate> getCandidates() {
+        return JingleCandidate.parse(this.getChildren());
+    }
+
+    public static S5BTransportInfo upgrade(final Element element) {
+        Preconditions.checkArgument(
+                "transport".equals(element.getName()), "Name of provided element is not transport");
+        Preconditions.checkArgument(
+                Namespace.JINGLE_TRANSPORTS_S5B.equals(element.getNamespace()),
+                "Element does not match s5b transport namespace");
+        final S5BTransportInfo transportInfo =
+                new S5BTransportInfo("transport", Namespace.JINGLE_TRANSPORTS_S5B);
+        transportInfo.setAttributes(element.getAttributes());
+        transportInfo.setChildren(element.getChildren());
+        return transportInfo;
+    }
+}

app/src/main/java/im/conversations/android/AbstractAccountService.java

@@ -0,0 +1,15 @@
+package im.conversations.android;
+
+import android.content.Context;
+import im.conversations.android.database.model.Account;
+
+public abstract class AbstractAccountService {
+
+    protected Context context;
+    protected Account account;
+
+    protected AbstractAccountService(final Context context, final Account account) {
+        this.context = context;
+        this.account = account;
+    }
+}

app/src/main/java/im/conversations/android/axolotl/AxolotlAddress.java

@@ -1,4 +1,4 @@
-package im.conversations.android.xmpp.axolotl;
+package im.conversations.android.axolotl;
 
 import org.jxmpp.jid.BareJid;
 import org.whispersystems.libsignal.SignalProtocolAddress;

app/src/main/java/im/conversations/android/axolotl/AxolotlDecryptionException.java

@@ -0,0 +1,12 @@
+package im.conversations.android.axolotl;
+
+public class AxolotlDecryptionException extends Exception {
+
+    public AxolotlDecryptionException(final String message) {
+        super(message);
+    }
+
+    public AxolotlDecryptionException(final Throwable throwable) {
+        super(throwable);
+    }
+}

app/src/main/java/im/conversations/android/axolotl/AxolotlEncryptionException.java

@@ -0,0 +1,16 @@
+package im.conversations.android.axolotl;
+
+public class AxolotlEncryptionException extends Exception {
+
+    public AxolotlEncryptionException(String msg) {
+        super(msg);
+    }
+
+    public AxolotlEncryptionException(String msg, Exception e) {
+        super(msg, e);
+    }
+
+    public AxolotlEncryptionException(Exception e) {
+        super(e);
+    }
+}

app/src/main/java/im/conversations/android/axolotl/AxolotlPayload.java

@@ -0,0 +1,27 @@
+package im.conversations.android.axolotl;
+
+import java.nio.charset.StandardCharsets;
+import org.whispersystems.libsignal.IdentityKey;
+
+public class AxolotlPayload {
+
+    public final AxolotlAddress axolotlAddress;
+    public final IdentityKey identityKey;
+    public final boolean preKeyMessage;
+    public final byte[] payload;
+
+    public AxolotlPayload(
+            AxolotlAddress axolotlAddress,
+            final IdentityKey identityKey,
+            final boolean preKeyMessage,
+            byte[] payload) {
+        this.axolotlAddress = axolotlAddress;
+        this.identityKey = identityKey;
+        this.preKeyMessage = preKeyMessage;
+        this.payload = payload;
+    }
+
+    public String payloadAsString() {
+        return new String(payload, StandardCharsets.UTF_8);
+    }
+}

app/src/main/java/im/conversations/android/axolotl/AxolotlService.java

@@ -0,0 +1,206 @@
+package im.conversations.android.axolotl;
+
+import android.content.Context;
+import android.os.Build;
+import com.google.common.base.Optional;
+import eu.siacs.conversations.xmpp.jingle.OmemoVerification;
+import im.conversations.android.AbstractAccountService;
+import im.conversations.android.database.AxolotlDatabaseStore;
+import im.conversations.android.database.model.Account;
+import im.conversations.android.xmpp.model.axolotl.Encrypted;
+import im.conversations.android.xmpp.model.axolotl.Header;
+import im.conversations.android.xmpp.model.axolotl.Key;
+import im.conversations.android.xmpp.model.axolotl.Payload;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+import org.jxmpp.jid.Jid;
+import org.whispersystems.libsignal.DuplicateMessageException;
+import org.whispersystems.libsignal.IdentityKey;
+import org.whispersystems.libsignal.InvalidKeyException;
+import org.whispersystems.libsignal.InvalidKeyIdException;
+import org.whispersystems.libsignal.InvalidMessageException;
+import org.whispersystems.libsignal.InvalidVersionException;
+import org.whispersystems.libsignal.LegacyMessageException;
+import org.whispersystems.libsignal.NoSessionException;
+import org.whispersystems.libsignal.UntrustedIdentityException;
+import org.whispersystems.libsignal.protocol.PreKeySignalMessage;
+import org.whispersystems.libsignal.protocol.SignalMessage;
+import org.whispersystems.libsignal.state.SessionRecord;
+import org.whispersystems.libsignal.state.SignalProtocolStore;
+
+public class AxolotlService extends AbstractAccountService {
+
+    public static final String KEY_TYPE = "AES";
+    public static final String CIPHER_MODE = "AES/GCM/NoPadding";
+
+    public static final String BOUNCY_CASTLE_PROVIDER = "BC";
+
+    private final SignalProtocolStore signalProtocolStore;
+
+    public AxolotlService(final Context context, final Account account) {
+        super(context, account);
+        this.signalProtocolStore = new AxolotlDatabaseStore(context, account);
+    }
+
+    private AxolotlSession buildReceivingSession(
+            final Jid from, final IdentityKey identityKey, final Header header) {
+        final Optional<Integer> sid = header.getSourceDevice();
+        if (sid.isPresent()) {
+            return AxolotlSession.of(
+                    signalProtocolStore,
+                    identityKey,
+                    new AxolotlAddress(from.asBareJid(), sid.get()));
+        }
+        throw new IllegalArgumentException("Header did not contain a source device id");
+    }
+
+    public AxolotlSession getExistingSession(final AxolotlAddress axolotlAddress) {
+        final SessionRecord sessionState = signalProtocolStore.loadSession(axolotlAddress);
+        if (sessionState == null) {
+            return null;
+        }
+        final IdentityKey identityKey = sessionState.getSessionState().getRemoteIdentityKey();
+        return AxolotlSession.of(signalProtocolStore, identityKey, axolotlAddress);
+    }
+
+    private AxolotlSession getExistingSessionOrThrow(final AxolotlAddress axolotlAddress)
+            throws NoSessionException {
+        final var session = getExistingSession(axolotlAddress);
+        if (session == null) {
+            throw new NoSessionException(
+                    String.format("No session for %s", axolotlAddress.toString()));
+        }
+        return session;
+    }
+
+    public AxolotlPayload decrypt(final Jid from, final Encrypted encrypted)
+            throws AxolotlDecryptionException {
+        try {
+            return decryptOrThrow(from, encrypted);
+        } catch (final IllegalArgumentException
+                | NotEncryptedForThisDeviceException
+                | InvalidMessageException
+                | InvalidVersionException
+                | UntrustedIdentityException
+                | DuplicateMessageException
+                | InvalidKeyIdException
+                | LegacyMessageException
+                | InvalidKeyException
+                | NoSessionException
+                | OutdatedSenderException
+                | NoSuchPaddingException
+                | NoSuchAlgorithmException
+                | NoSuchProviderException
+                | InvalidAlgorithmParameterException
+                | java.security.InvalidKeyException
+                | IllegalBlockSizeException
+                | BadPaddingException e) {
+            throw new AxolotlDecryptionException(e);
+        }
+    }
+
+    private AxolotlPayload decryptOrThrow(final Jid from, final Encrypted encrypted)
+            throws NotEncryptedForThisDeviceException, InvalidMessageException,
+                    InvalidVersionException, UntrustedIdentityException, DuplicateMessageException,
+                    InvalidKeyIdException, LegacyMessageException, InvalidKeyException,
+                    NoSessionException, OutdatedSenderException, NoSuchPaddingException,
+                    NoSuchAlgorithmException, NoSuchProviderException,
+                    InvalidAlgorithmParameterException, java.security.InvalidKeyException,
+                    IllegalBlockSizeException, BadPaddingException {
+        final Payload payload = encrypted.getPayload();
+        final Header header = encrypted.getHeader();
+        final Key ourKey = header.getKey(signalProtocolStore.getLocalRegistrationId());
+        if (ourKey == null) {
+            throw new NotEncryptedForThisDeviceException();
+        }
+        final byte[] keyWithAuthTag;
+        final AxolotlSession session;
+        final boolean preKeyMessage;
+        if (ourKey.isPreKey()) {
+            final PreKeySignalMessage preKeySignalMessage =
+                    new PreKeySignalMessage(ourKey.asBytes());
+            preKeyMessage = true;
+            session = buildReceivingSession(from, preKeySignalMessage.getIdentityKey(), header);
+            keyWithAuthTag = session.sessionCipher.decrypt(preKeySignalMessage);
+        } else {
+            final SignalMessage signalMessage = new SignalMessage(ourKey.asBytes());
+            preKeyMessage = false;
+            session =
+                    getExistingSessionOrThrow(
+                            new AxolotlAddress(from.asBareJid(), header.getSourceDevice().get()));
+            keyWithAuthTag = session.sessionCipher.decrypt(signalMessage);
+        }
+        if (keyWithAuthTag.length < 32) {
+            throw new OutdatedSenderException(
+                    "Key did not contain auth tag. Sender needs to update their OMEMO client");
+        }
+        if (payload == null) {
+            return new AxolotlPayload(
+                    session.axolotlAddress, session.identityKey, preKeyMessage, null);
+        }
+        final byte[] key = new byte[16];
+        final byte[] authTag = new byte[16];
+        final byte[] iv = header.getIv();
+        System.arraycopy(keyWithAuthTag, 0, key, 0, key.length);
+        System.arraycopy(keyWithAuthTag, key.length, authTag, 0, authTag.length);
+        final Cipher cipher;
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            cipher = Cipher.getInstance(CIPHER_MODE);
+        } else {
+            cipher = Cipher.getInstance(CIPHER_MODE, BOUNCY_CASTLE_PROVIDER);
+        }
+        final SecretKey secretKey = new SecretKeySpec(key, KEY_TYPE);
+        final IvParameterSpec ivSpec = new IvParameterSpec(iv);
+        cipher.init(Cipher.DECRYPT_MODE, secretKey, ivSpec);
+        final byte[] payloadAsBytes = payload.asBytes();
+        final byte[] payloadWithAuthTag = new byte[payloadAsBytes.length + 16];
+        System.arraycopy(payloadAsBytes, 0, payloadWithAuthTag, 0, payloadAsBytes.length);
+        System.arraycopy(authTag, 0, payloadWithAuthTag, payloadAsBytes.length, authTag.length);
+        final byte[] decryptedPayload = cipher.doFinal(payloadWithAuthTag);
+        return new AxolotlPayload(
+                session.axolotlAddress, session.identityKey, preKeyMessage, decryptedPayload);
+    }
+
+    public SignalProtocolStore getSignalProtocolStore() {
+        return this.signalProtocolStore;
+    }
+
+    public static class OmemoVerifiedPayload<T> {
+        private final int deviceId;
+        private final IdentityKey identityKey;
+        private final T payload;
+
+        public OmemoVerifiedPayload(OmemoVerification omemoVerification, T payload) {
+            this.deviceId = omemoVerification.getDeviceId();
+            this.identityKey = omemoVerification.getFingerprint();
+            this.payload = payload;
+        }
+
+        public int getDeviceId() {
+            return deviceId;
+        }
+
+        public IdentityKey getFingerprint() {
+            return identityKey;
+        }
+
+        public T getPayload() {
+            return payload;
+        }
+    }
+
+    public static class NotVerifiedException extends SecurityException {
+
+        public NotVerifiedException(String message) {
+            super(message);
+        }
+    }
+}

app/src/main/java/im/conversations/android/axolotl/AxolotlSession.java

@@ -0,0 +1,29 @@
+package im.conversations.android.axolotl;
+
+import org.whispersystems.libsignal.IdentityKey;
+import org.whispersystems.libsignal.SessionCipher;
+import org.whispersystems.libsignal.state.SignalProtocolStore;
+
+public class AxolotlSession {
+
+    public final AxolotlAddress axolotlAddress;
+    public final IdentityKey identityKey;
+    public final SessionCipher sessionCipher;
+
+    private AxolotlSession(
+            AxolotlAddress axolotlAddress,
+            final IdentityKey identityKey,
+            SessionCipher sessionCipher) {
+        this.axolotlAddress = axolotlAddress;
+        this.identityKey = identityKey;
+        this.sessionCipher = sessionCipher;
+    }
+
+    public static AxolotlSession of(
+            final SignalProtocolStore signalProtocolStore,
+            final IdentityKey identityKey,
+            final AxolotlAddress axolotlAddress) {
+        final var sessionCipher = new SessionCipher(signalProtocolStore, axolotlAddress);
+        return new AxolotlSession(axolotlAddress, identityKey, sessionCipher);
+    }
+}

app/src/main/java/im/conversations/android/axolotl/EncryptionBuilder.java

@@ -0,0 +1,157 @@
+package im.conversations.android.axolotl;
+
+import android.annotation.SuppressLint;
+import android.os.Build;
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import im.conversations.android.Conversations;
+import im.conversations.android.xmpp.model.axolotl.Encrypted;
+import im.conversations.android.xmpp.model.axolotl.Header;
+import im.conversations.android.xmpp.model.axolotl.Key;
+import im.conversations.android.xmpp.model.axolotl.Payload;
+import java.nio.charset.StandardCharsets;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+import java.security.NoSuchProviderException;
+import java.util.ArrayList;
+import java.util.List;
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.KeyGenerator;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+import org.whispersystems.libsignal.UntrustedIdentityException;
+import org.whispersystems.libsignal.protocol.CiphertextMessage;
+
+public class EncryptionBuilder {
+
+    private Long sourceDeviceId;
+
+    private ArrayList<AxolotlSession> sessions;
+
+    private byte[] payload;
+
+    public Encrypted build() throws AxolotlEncryptionException {
+        try {
+            return buildOrThrow();
+        } catch (final InvalidAlgorithmParameterException
+                | NoSuchPaddingException
+                | IllegalBlockSizeException
+                | NoSuchAlgorithmException
+                | BadPaddingException
+                | NoSuchProviderException
+                | InvalidKeyException
+                | UntrustedIdentityException e) {
+            throw new AxolotlEncryptionException(e);
+        }
+    }
+
+    private Encrypted buildOrThrow()
+            throws InvalidAlgorithmParameterException, NoSuchPaddingException,
+                    IllegalBlockSizeException, NoSuchAlgorithmException, BadPaddingException,
+                    NoSuchProviderException, InvalidKeyException, UntrustedIdentityException {
+        final long sourceDeviceId =
+                Preconditions.checkNotNull(this.sourceDeviceId, "Specify a source device id");
+        final var payloadCleartext = Preconditions.checkNotNull(this.payload, "Specify a payload");
+        Preconditions.checkState(sessions.size() > 0, "Add at least on session");
+        final var sessions = ImmutableList.copyOf(this.sessions);
+        final var key = generateKey();
+        final var iv = generateIv();
+        final var encryptedPayload = encrypt(payloadCleartext, key, iv);
+        final var keyWithAuthTag = new byte[32];
+        System.arraycopy(key, 0, keyWithAuthTag, 0, key.length);
+        System.arraycopy(
+                encryptedPayload.authTag, 0, keyWithAuthTag, 16, encryptedPayload.authTag.length);
+        final var header = buildHeader(sessions, keyWithAuthTag);
+        header.addIv(iv);
+        header.setSourceDevice(sourceDeviceId);
+        final var encrypted = new Encrypted();
+        encrypted.addExtension(header);
+        final var payload = encrypted.addExtension(new Payload());
+        payload.setContent(encryptedPayload.encrypted);
+        return encrypted;
+    }
+
+    public EncryptionBuilder payload(final String payload) {
+        this.payload = payload.getBytes(StandardCharsets.UTF_8);
+        return this;
+    }
+
+    public EncryptionBuilder session(final AxolotlSession session) {
+        this.sessions.add(session);
+        return this;
+    }
+
+    public EncryptionBuilder sourceDeviceId(final long sourceDeviceId) {
+        this.sourceDeviceId = sourceDeviceId;
+        return this;
+    }
+
+    private Header buildHeader(List<AxolotlSession> sessions, final byte[] keyWithAuthTag)
+            throws UntrustedIdentityException {
+        final var header = new Header();
+        for (final AxolotlSession session : sessions) {
+            final var cipherMessage = session.sessionCipher.encrypt(keyWithAuthTag);
+            final var key = header.addExtension(new Key());
+            key.setContent(cipherMessage.serialize());
+            key.setIsPreKey(cipherMessage.getType() == CiphertextMessage.PREKEY_TYPE);
+        }
+        return header;
+    }
+
+    @SuppressLint("DeprecatedProvider")
+    private static EncryptedPayload encrypt(
+            final byte[] payloadCleartext, final byte[] key, final byte[] iv)
+            throws NoSuchPaddingException, NoSuchAlgorithmException, NoSuchProviderException,
+                    IllegalBlockSizeException, BadPaddingException,
+                    InvalidAlgorithmParameterException, InvalidKeyException {
+        final Cipher cipher;
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            cipher = Cipher.getInstance(AxolotlService.CIPHER_MODE);
+        } else {
+            cipher =
+                    Cipher.getInstance(
+                            AxolotlService.CIPHER_MODE, AxolotlService.BOUNCY_CASTLE_PROVIDER);
+        }
+        final SecretKey secretKey = new SecretKeySpec(key, AxolotlService.KEY_TYPE);
+        final IvParameterSpec ivSpec = new IvParameterSpec(iv);
+        cipher.init(Cipher.ENCRYPT_MODE, secretKey, ivSpec);
+        final var encryptedWithAuthTag = cipher.doFinal(payloadCleartext);
+        final var authTag = new byte[16];
+        final var encrypted = new byte[encryptedWithAuthTag.length - authTag.length];
+
+        System.arraycopy(encryptedWithAuthTag, 0, encrypted, 0, encrypted.length);
+        System.arraycopy(encryptedWithAuthTag, encrypted.length, authTag, 0, authTag.length);
+        return new EncryptedPayload(encrypted, authTag);
+    }
+
+    private static byte[] generateKey() {
+        try {
+            KeyGenerator generator = KeyGenerator.getInstance(AxolotlService.KEY_TYPE);
+            generator.init(128);
+            return generator.generateKey().getEncoded();
+        } catch (final NoSuchAlgorithmException e) {
+            throw new AssertionError(e);
+        }
+    }
+
+    private static final class EncryptedPayload {
+        public final byte[] encrypted;
+        public final byte[] authTag;
+
+        private EncryptedPayload(byte[] encrypted, byte[] authTag) {
+            this.encrypted = encrypted;
+            this.authTag = authTag;
+        }
+    }
+
+    private static byte[] generateIv() {
+        final byte[] iv = new byte[12];
+        Conversations.SECURE_RANDOM.nextBytes(iv);
+        return iv;
+    }
+}

app/src/main/java/im/conversations/android/axolotl/NotEncryptedForThisDeviceException.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (c) 2018, Daniel Gultsch All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation and/or
+ * other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package im.conversations.android.axolotl;
+
+public class NotEncryptedForThisDeviceException extends AxolotlEncryptionException {
+    public NotEncryptedForThisDeviceException() {
+        super("Message was not encrypted for this device");
+    }
+}

app/src/main/java/im/conversations/android/axolotl/OutdatedSenderException.java

@@ -0,0 +1,8 @@
+package im.conversations.android.axolotl;
+
+public class OutdatedSenderException extends AxolotlDecryptionException {
+
+    public OutdatedSenderException(final String message) {
+        super(message);
+    }
+}

app/src/main/java/im/conversations/android/database/AxolotlDatabaseStore.java

@@ -1,9 +1,10 @@
 package im.conversations.android.database;
 
 import android.content.Context;
+import im.conversations.android.AbstractAccountService;
+import im.conversations.android.axolotl.AxolotlAddress;
 import im.conversations.android.database.dao.AxolotlDao;
 import im.conversations.android.database.model.Account;
-import im.conversations.android.xmpp.axolotl.AxolotlAddress;
 import java.util.List;
 import org.whispersystems.libsignal.IdentityKey;
 import org.whispersystems.libsignal.IdentityKeyPair;
@@ -14,14 +15,10 @@ import org.whispersystems.libsignal.state.SessionRecord;
 import org.whispersystems.libsignal.state.SignalProtocolStore;
 import org.whispersystems.libsignal.state.SignedPreKeyRecord;
 
-public class AxolotlDatabaseStore implements SignalProtocolStore {
-
-    private final Context context;
-    private final Account account;
+public class AxolotlDatabaseStore extends AbstractAccountService implements SignalProtocolStore {
 
     public AxolotlDatabaseStore(final Context context, final Account account) {
-        this.context = context;
-        this.account = account;
+        super(context, account);
     }
 
     private AxolotlDao axolotlDao() {

app/src/main/java/im/conversations/android/database/dao/DiscoDao.java

@@ -26,6 +26,7 @@ import im.conversations.android.xmpp.model.disco.info.Identity;
 import im.conversations.android.xmpp.model.disco.info.InfoQuery;
 import im.conversations.android.xmpp.model.disco.items.Item;
 import java.util.Collection;
+import org.jxmpp.jid.BareJid;
 import org.jxmpp.jid.Jid;
 import org.jxmpp.jid.parts.Resourcepart;
 
@@ -186,5 +187,44 @@ public abstract class DiscoDao {
             "SELECT EXISTS (SELECT disco_item.id FROM disco_item JOIN disco_feature on"
                     + " disco_item.discoId=disco_feature.discoId WHERE accountId=:account AND"
                     + " address=:entity AND feature=:feature)")
-    public abstract boolean hasFeature(final long account, final Jid entity, final String feature);
+    protected abstract boolean hasDiscoItemFeature(
+            final long account, final Jid entity, final String feature);
+
+    @Query(
+            "SELECT EXISTS (SELECT presence.id FROM presence JOIN disco_feature on"
+                    + " presence.discoId=disco_feature.discoId WHERE accountId=:account AND"
+                    + " address=:address AND resource=:resource AND feature=:feature)")
+    protected abstract boolean hasPresenceFeature(
+            final long account,
+            final BareJid address,
+            final Resourcepart resource,
+            final String feature);
+
+    @Query(
+            "SELECT count(presence.id) FROM presence JOIN disco_feature on"
+                    + " presence.discoId=disco_feature.discoId WHERE accountId=:account AND"
+                    + " address=:address AND feature=:feature")
+    public abstract int countPresencesWithFeature(
+            final long account, final BareJid address, final String feature);
+
+    public int countPresencesWithFeature(final Account account, final String feature) {
+        return countPresencesWithFeature(account.id, account.address, feature);
+    }
+
+    public boolean hasFeature(final long account, final Entity entity, final String feature) {
+        if (entity instanceof Entity.DiscoItem) {
+            return hasDiscoItemFeature(account, entity.address, feature);
+        }
+        if (entity instanceof Entity.Presence) {
+            return hasPresenceFeature(
+                    account,
+                    entity.address.asBareJid(),
+                    entity.address.getResourceOrEmpty(),
+                    feature);
+        }
+        throw new IllegalStateException(
+                String.format(
+                        "Discovering features for %s is not implemented",
+                        entity.getClass().getName()));
+    }
 }

app/src/main/java/im/conversations/android/database/dao/RosterDao.java

@@ -12,6 +12,7 @@ import im.conversations.android.database.entity.RosterItemGroupEntity;
 import im.conversations.android.database.model.Account;
 import im.conversations.android.xmpp.model.roster.Item;
 import java.util.Collection;
+import org.jxmpp.jid.BareJid;
 import org.jxmpp.jid.Jid;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -33,6 +34,9 @@ public abstract class RosterDao extends GroupDao {
     @Query("UPDATE account SET rosterVersion=:version WHERE id=:account")
     protected abstract void setRosterVersion(final long account, final String version);
 
+    @Query("SELECT EXISTS (SELECT id FROM roster WHERE accountId=:account AND address=:address)")
+    public abstract boolean isInRoster(final long account, final BareJid address);
+
     @Transaction
     public void set(
             final Account account, final String version, final Collection<Item> rosterItems) {

app/src/main/java/im/conversations/android/notification/AbstractNotification.java

@@ -0,0 +1,28 @@
+package im.conversations.android.notification;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import androidx.preference.PreferenceManager;
+import im.conversations.android.R;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+
+public abstract class AbstractNotification {
+
+    protected static final ScheduledExecutorService SCHEDULED_EXECUTOR_SERVICE =
+            Executors.newSingleThreadScheduledExecutor();
+
+    protected final Context context;
+
+    protected AbstractNotification(final Context context) {
+        this.context = context;
+    }
+
+    public boolean notificationsFromStrangers() {
+        final SharedPreferences preferences =
+                PreferenceManager.getDefaultSharedPreferences(context);
+        return preferences.getBoolean(
+                "notifications_from_strangers",
+                context.getResources().getBoolean(R.bool.notifications_from_strangers));
+    }
+}

app/src/main/java/im/conversations/android/notification/Channels.java

@@ -11,10 +11,11 @@ import im.conversations.android.R;
 
 public final class Channels {
 
-    private final Application application;
-
-    private static final String CHANNEL_GROUP_STATUS = "status";
     static final String CHANNEL_FOREGROUND = "foreground";
+    static final String INCOMING_CALLS_NOTIFICATION_CHANNEL = "incoming_calls_channel";
+    static final String CHANNEL_GROUP_STATUS = "status";
+    static final String CHANNEL_GROUP_CALLS = "calls";
+    private final Application application;
 
     public Channels(final Application application) {
         this.application = application;
@@ -29,6 +30,8 @@ public final class Channels {
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             this.initializeGroups(notificationManager);
             this.initializeForegroundChannel(notificationManager);
+
+            this.initializeIncomingCallChannel(notificationManager);
         }
     }
 
@@ -38,6 +41,10 @@ public final class Channels {
                 new NotificationChannelGroup(
                         CHANNEL_GROUP_STATUS,
                         application.getString(R.string.notification_group_status_information)));
+        notificationManager.createNotificationChannelGroup(
+                new NotificationChannelGroup(
+                        CHANNEL_GROUP_CALLS,
+                        application.getString(R.string.notification_group_calls)));
     }
 
     @RequiresApi(api = Build.VERSION_CODES.O)
@@ -55,4 +62,21 @@ public final class Channels {
         foregroundServiceChannel.setGroup(CHANNEL_GROUP_STATUS);
         notificationManager.createNotificationChannel(foregroundServiceChannel);
     }
+
+    @RequiresApi(api = Build.VERSION_CODES.O)
+    private void initializeIncomingCallChannel(final NotificationManager notificationManager) {
+        final NotificationChannel incomingCallsChannel =
+                new NotificationChannel(
+                        INCOMING_CALLS_NOTIFICATION_CHANNEL,
+                        application.getString(R.string.incoming_calls_channel_name),
+                        NotificationManager.IMPORTANCE_HIGH);
+        incomingCallsChannel.setSound(null, null);
+        incomingCallsChannel.setShowBadge(false);
+        incomingCallsChannel.setLightColor(RtpSessionNotification.LED_COLOR);
+        incomingCallsChannel.enableLights(true);
+        incomingCallsChannel.setGroup(CHANNEL_GROUP_CALLS);
+        incomingCallsChannel.setBypassDnd(true);
+        incomingCallsChannel.enableVibration(false);
+        notificationManager.createNotificationChannel(incomingCallsChannel);
+    }
 }

app/src/main/java/im/conversations/android/notification/ForegroundServiceNotification.java

@@ -11,28 +11,26 @@ import im.conversations.android.R;
 import im.conversations.android.ui.activity.MainActivity;
 import im.conversations.android.xmpp.ConnectionPool;
 
-public class ForegroundServiceNotification {
+public class ForegroundServiceNotification extends AbstractNotification {
 
     public static final int ID = 1;
 
-    private final Service service;
-
     public ForegroundServiceNotification(final Service service) {
-        this.service = service;
+        super(service);
     }
 
     public Notification build(final ConnectionPool.Summary summary) {
-        final Notification.Builder builder = new Notification.Builder(service);
+        final Notification.Builder builder = new Notification.Builder(context);
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
             // starting with Android 7 the app name is displayed as part of the notification
             // this means we do not have to repeat it in the 'content title'
             builder.setContentTitle(
-                    service.getString(
+                    context.getString(
                             R.string.connected_accounts, summary.connected, summary.total));
         } else {
-            builder.setContentTitle(service.getString(R.string.app_name));
+            builder.setContentTitle(context.getString(R.string.app_name));
             builder.setContentText(
-                    service.getString(
+                    context.getString(
                             R.string.connected_accounts, summary.connected, summary.total));
         }
         builder.setContentIntent(buildPendingIntent());
@@ -53,15 +51,15 @@ public class ForegroundServiceNotification {
 
     private PendingIntent buildPendingIntent() {
         return PendingIntent.getActivity(
-                service,
+                context,
                 0,
-                new Intent(service, MainActivity.class),
+                new Intent(context, MainActivity.class),
                 PendingIntent.FLAG_IMMUTABLE | PendingIntent.FLAG_UPDATE_CURRENT);
     }
 
     public void update(final ConnectionPool.Summary summary) {
         final var notificationManager =
-                ContextCompat.getSystemService(service, NotificationManager.class);
+                ContextCompat.getSystemService(context, NotificationManager.class);
         if (notificationManager == null) {
             return;
         }

app/src/main/java/im/conversations/android/notification/OngoingCall.java

@@ -0,0 +1,34 @@
+package im.conversations.android.notification;
+
+import com.google.common.base.Objects;
+import eu.siacs.conversations.xmpp.jingle.AbstractJingleConnection;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import java.util.Set;
+
+public class OngoingCall {
+    public final AbstractJingleConnection.Id id;
+    public final Set<Media> media;
+    public final boolean reconnecting;
+
+    public OngoingCall(
+            AbstractJingleConnection.Id id, Set<Media> media, final boolean reconnecting) {
+        this.id = id;
+        this.media = media;
+        this.reconnecting = reconnecting;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        OngoingCall that = (OngoingCall) o;
+        return reconnecting == that.reconnecting
+                && Objects.equal(id, that.id)
+                && Objects.equal(media, that.media);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(id, media, reconnecting);
+    }
+}

app/src/main/java/im/conversations/android/notification/RtpSessionNotification.java

@@ -0,0 +1,284 @@
+package im.conversations.android.notification;
+
+import android.Manifest;
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.app.PendingIntent;
+import android.content.Context;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.content.pm.PackageManager;
+import android.content.res.Resources;
+import android.media.Ringtone;
+import android.media.RingtoneManager;
+import android.net.Uri;
+import android.os.Build;
+import android.os.Vibrator;
+import android.preference.PreferenceManager;
+import android.util.Log;
+import androidx.core.app.ActivityCompat;
+import androidx.core.app.NotificationCompat;
+import androidx.core.app.NotificationManagerCompat;
+import androidx.core.content.ContextCompat;
+import com.google.common.base.Strings;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.xmpp.jingle.AbstractJingleConnection;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import im.conversations.android.R;
+import im.conversations.android.database.model.Account;
+import im.conversations.android.service.RtpSessionService;
+import im.conversations.android.transformer.CallLogEntry;
+import im.conversations.android.ui.activity.RtpSessionActivity;
+import java.util.Set;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class RtpSessionNotification extends AbstractNotification {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(RtpSessionNotification.class);
+
+    public static final int INCOMING_CALL_ID = 2;
+
+    public static final int LED_COLOR = 0xff00ff00;
+
+    private static final long[] CALL_PATTERN = {0, 500, 300, 600};
+
+    private Ringtone currentlyPlayingRingtone = null;
+    private ScheduledFuture<?> vibrationFuture;
+
+    public RtpSessionNotification(Context context) {
+        super(context);
+    }
+
+    public void cancelIncomingCallNotification() {
+        stopSoundAndVibration();
+        cancel(INCOMING_CALL_ID);
+    }
+
+    public boolean stopSoundAndVibration() {
+        int stopped = 0;
+        if (this.currentlyPlayingRingtone != null) {
+            if (this.currentlyPlayingRingtone.isPlaying()) {
+                Log.d(Config.LOGTAG, "stop playing ring tone");
+                ++stopped;
+            }
+            this.currentlyPlayingRingtone.stop();
+        }
+        if (this.vibrationFuture != null && !this.vibrationFuture.isCancelled()) {
+            Log.d(Config.LOGTAG, "stop vibration");
+            this.vibrationFuture.cancel(true);
+            ++stopped;
+        }
+        return stopped > 0;
+    }
+
+    private void notify(int id, Notification notification) {
+        final var notificationManager = NotificationManagerCompat.from(context);
+        try {
+            if (ActivityCompat.checkSelfPermission(context, Manifest.permission.POST_NOTIFICATIONS)
+                    != PackageManager.PERMISSION_GRANTED) {
+                LOGGER.warn("Lacking notification permission");
+                return;
+            }
+            notificationManager.notify(id, notification);
+        } catch (final RuntimeException e) {
+            LOGGER.warn("Could not post notification", e);
+        }
+    }
+
+    private void cancel(final int notificationId) {
+        final var notificationManager = NotificationManagerCompat.from(context);
+        notificationManager.cancel(notificationId);
+    }
+
+    public synchronized void startRinging(
+            final Account account, final AbstractJingleConnection.Id id, final Set<Media> media) {
+        showIncomingCallNotification(account, id, media);
+        final NotificationManager notificationManager =
+                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        final int currentInterruptionFilter;
+        if (notificationManager != null) {
+            currentInterruptionFilter = notificationManager.getCurrentInterruptionFilter();
+        } else {
+            currentInterruptionFilter = 1; // INTERRUPTION_FILTER_ALL
+        }
+        if (currentInterruptionFilter != 1) {
+            Log.d(
+                    Config.LOGTAG,
+                    "do not ring or vibrate because interruption filter has been set to "
+                            + currentInterruptionFilter);
+            return;
+        }
+        final ScheduledFuture<?> currentVibrationFuture = this.vibrationFuture;
+        this.vibrationFuture =
+                SCHEDULED_EXECUTOR_SERVICE.scheduleAtFixedRate(
+                        new VibrationRunnable(), 0, 3, TimeUnit.SECONDS);
+        if (currentVibrationFuture != null) {
+            currentVibrationFuture.cancel(true);
+        }
+        final SharedPreferences preferences =
+                PreferenceManager.getDefaultSharedPreferences(context);
+        final Resources resources = context.getResources();
+        final String ringtonePreference =
+                preferences.getString(
+                        "call_ringtone", resources.getString(R.string.incoming_call_ringtone));
+        if (Strings.isNullOrEmpty(ringtonePreference)) {
+            Log.d(Config.LOGTAG, "ringtone has been set to none");
+            return;
+        }
+        final Uri uri = Uri.parse(ringtonePreference);
+        this.currentlyPlayingRingtone = RingtoneManager.getRingtone(context, uri);
+        if (this.currentlyPlayingRingtone == null) {
+            Log.d(Config.LOGTAG, "unable to find ringtone for uri " + uri);
+            return;
+        }
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+            this.currentlyPlayingRingtone.setLooping(true);
+        }
+        this.currentlyPlayingRingtone.play();
+    }
+
+    private void showIncomingCallNotification(
+            final Account account, final AbstractJingleConnection.Id id, final Set<Media> media) {
+        final Intent fullScreenIntent = new Intent(context, RtpSessionActivity.class);
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_ACCOUNT, account.id);
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_WITH, id.with.toString());
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_SESSION_ID, id.sessionId);
+        fullScreenIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
+        fullScreenIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
+        final NotificationCompat.Builder builder =
+                new NotificationCompat.Builder(
+                        context, Channels.INCOMING_CALLS_NOTIFICATION_CHANNEL);
+        if (media.contains(Media.VIDEO)) {
+            builder.setSmallIcon(R.drawable.ic_videocam_24dp);
+            builder.setContentTitle(context.getString(R.string.rtp_state_incoming_video_call));
+        } else {
+            builder.setSmallIcon(R.drawable.ic_call_24dp);
+            builder.setContentTitle(context.getString(R.string.rtp_state_incoming_call));
+        }
+        // TODO fix me once we have a contact model
+        /*final Contact contact = id.getContact();
+        builder.setLargeIcon(
+                mXmppConnectionService
+                        .getAvatarService()
+                        .get(contact, AvatarService.getSystemUiAvatarSize(mXmppConnectionService)));
+        final Uri systemAccount = contact.getSystemAccount();
+        if (systemAccount != null) {
+            builder.addPerson(systemAccount.toString());
+        }
+        builder.setContentText(id.account.getRoster().getContact(id.with).getDisplayName());*/
+        builder.setVisibility(NotificationCompat.VISIBILITY_PUBLIC);
+        builder.setPriority(NotificationCompat.PRIORITY_HIGH);
+        builder.setCategory(NotificationCompat.CATEGORY_CALL);
+        PendingIntent pendingIntent = createPendingRtpSession(account, id, Intent.ACTION_VIEW, 101);
+        builder.setFullScreenIntent(pendingIntent, true);
+        builder.setContentIntent(pendingIntent); // old androids need this?
+        builder.setOngoing(true);
+        builder.addAction(
+                new NotificationCompat.Action.Builder(
+                                R.drawable.ic_call_end_24dp,
+                                context.getString(R.string.dismiss_call),
+                                createCallAction(
+                                        id.sessionId, RtpSessionService.ACTION_DISMISS_CALL, 102))
+                        .build());
+        builder.addAction(
+                new NotificationCompat.Action.Builder(
+                                R.drawable.ic_call_24dp,
+                                context.getString(R.string.answer_call),
+                                createPendingRtpSession(
+                                        account, id, RtpSessionActivity.ACTION_ACCEPT_CALL, 103))
+                        .build());
+        modifyIncomingCall(builder);
+        final Notification notification = builder.build();
+        notification.flags = notification.flags | Notification.FLAG_INSISTENT;
+        notify(INCOMING_CALL_ID, notification);
+    }
+
+    public Notification getOngoingCallNotification(final Account account, OngoingCall ongoingCall) {
+        final AbstractJingleConnection.Id id = ongoingCall.id;
+        final NotificationCompat.Builder builder =
+                new NotificationCompat.Builder(context, "ongoing_calls");
+        if (ongoingCall.media.contains(Media.VIDEO)) {
+            builder.setSmallIcon(R.drawable.ic_videocam_24dp);
+            if (ongoingCall.reconnecting) {
+                builder.setContentTitle(context.getString(R.string.reconnecting_video_call));
+            } else {
+                builder.setContentTitle(context.getString(R.string.ongoing_video_call));
+            }
+        } else {
+            builder.setSmallIcon(R.drawable.ic_call_24dp);
+            if (ongoingCall.reconnecting) {
+                builder.setContentTitle(context.getString(R.string.reconnecting_call));
+            } else {
+                builder.setContentTitle(context.getString(R.string.ongoing_call));
+            }
+        }
+        // TODO fix me when we have a Contact model
+        // builder.setContentText(id.account.getRoster().getContact(id.with).getDisplayName());
+        builder.setVisibility(NotificationCompat.VISIBILITY_PUBLIC);
+        builder.setPriority(NotificationCompat.PRIORITY_HIGH);
+        builder.setCategory(NotificationCompat.CATEGORY_CALL);
+        builder.setContentIntent(createPendingRtpSession(account, id, Intent.ACTION_VIEW, 101));
+        builder.setOngoing(true);
+        builder.addAction(
+                new NotificationCompat.Action.Builder(
+                                R.drawable.ic_call_end_24dp,
+                                context.getString(R.string.hang_up),
+                                createCallAction(
+                                        id.sessionId, RtpSessionService.ACTION_END_CALL, 104))
+                        .build());
+        return builder.build();
+    }
+
+    private PendingIntent createPendingRtpSession(
+            final Account account,
+            final AbstractJingleConnection.Id id,
+            final String action,
+            final int requestCode) {
+        final Intent fullScreenIntent = new Intent(context, RtpSessionActivity.class);
+        fullScreenIntent.setAction(action);
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_ACCOUNT, account.id);
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_WITH, id.with.toString());
+        fullScreenIntent.putExtra(RtpSessionActivity.EXTRA_SESSION_ID, id.sessionId);
+        return PendingIntent.getActivity(
+                context,
+                requestCode,
+                fullScreenIntent,
+                PendingIntent.FLAG_IMMUTABLE | PendingIntent.FLAG_UPDATE_CURRENT);
+    }
+
+    private PendingIntent createCallAction(String sessionId, final String action, int requestCode) {
+        final Intent intent = new Intent(context, RtpSessionService.class);
+        intent.setAction(action);
+        intent.setPackage(context.getPackageName());
+        intent.putExtra(RtpSessionActivity.EXTRA_SESSION_ID, sessionId);
+        return PendingIntent.getService(
+                context,
+                requestCode,
+                intent,
+                PendingIntent.FLAG_MUTABLE | PendingIntent.FLAG_UPDATE_CURRENT);
+    }
+
+    private void modifyIncomingCall(final NotificationCompat.Builder mBuilder) {
+        mBuilder.setPriority(NotificationCompat.PRIORITY_HIGH);
+        setNotificationColor(mBuilder);
+        mBuilder.setLights(LED_COLOR, 2000, 3000);
+    }
+
+    private void setNotificationColor(final NotificationCompat.Builder mBuilder) {
+        mBuilder.setColor(ContextCompat.getColor(context, R.color.seed));
+    }
+
+    public void pushMissedCallNow(CallLogEntry message) {}
+
+    private class VibrationRunnable implements Runnable {
+
+        @Override
+        public void run() {
+            final Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
+            vibrator.vibrate(CALL_PATTERN, -1);
+        }
+    }
+}

app/src/main/java/im/conversations/android/service/RtpSessionService.java

@@ -0,0 +1,16 @@
+package im.conversations.android.service;
+
+import android.content.Intent;
+import androidx.lifecycle.LifecycleService;
+
+public class RtpSessionService extends LifecycleService {
+
+    public static final String ACTION_DISMISS_CALL = "dismiss_call";
+    public static final String ACTION_END_CALL = "end_call";
+
+    @Override
+    public int onStartCommand(final Intent intent, final int flags, final int startId) {
+
+        return super.onStartCommand(intent, flags, startId);
+    }
+}

app/src/main/java/im/conversations/android/tls/TrustManager.java

@@ -1,19 +1,16 @@
 package im.conversations.android.tls;
 
 import android.content.Context;
+import im.conversations.android.AbstractAccountService;
 import im.conversations.android.database.model.Account;
 import java.security.cert.CertificateException;
 import java.security.cert.X509Certificate;
 import javax.net.ssl.X509TrustManager;
 
-public class TrustManager implements X509TrustManager {
-
-    private final Context context;
-    private final Account account;
+public class TrustManager extends AbstractAccountService implements X509TrustManager {
 
     public TrustManager(final Context context, final Account account) {
-        this.context = context;
-        this.account = account;
+        super(context, account);
     }
 
     @Override

app/src/main/java/im/conversations/android/transformer/CallLogEntry.java

@@ -0,0 +1,11 @@
+package im.conversations.android.transformer;
+
+public class CallLogEntry {
+    public void setServerMsgId(String serverMsgId) {}
+
+    public void setCarbon(boolean b) {}
+
+    public void markUnread() {}
+
+    public void setDuration(long duration) {}
+}

app/src/main/java/im/conversations/android/transformer/TransformationFactory.java

@@ -2,6 +2,7 @@ package im.conversations.android.transformer;
 
 import android.content.Context;
 import im.conversations.android.xml.Namespace;
+import im.conversations.android.xmpp.Entity;
 import im.conversations.android.xmpp.XmppConnection;
 import im.conversations.android.xmpp.manager.DiscoManager;
 import im.conversations.android.xmpp.model.occupant.OccupantId;
@@ -34,7 +35,8 @@ public class TransformationFactory extends XmppConnection.Delegate {
         if (message.getType() == Message.Type.GROUPCHAT && message.hasExtension(OccupantId.class)) {
             if (from != null
                     && getManager(DiscoManager.class)
-                            .hasFeature(from.asBareJid(), Namespace.OCCUPANT_ID)) {
+                            .hasFeature(
+                                    Entity.discoItem(from.asBareJid()), Namespace.OCCUPANT_ID)) {
                 occupantId = message.getExtension(OccupantId.class).getId();
             } else {
                 occupantId = null;

app/src/main/java/im/conversations/android/ui/model/RtpSessionViewModel.java

@@ -0,0 +1,50 @@
+package im.conversations.android.ui.model;
+
+import android.app.Application;
+import androidx.annotation.NonNull;
+import androidx.lifecycle.AndroidViewModel;
+import com.google.common.util.concurrent.FutureCallback;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.MoreExecutors;
+import im.conversations.android.xmpp.ConnectionPool;
+import im.conversations.android.xmpp.manager.JingleConnectionManager;
+import java.util.function.Consumer;
+
+public class RtpSessionViewModel extends AndroidViewModel {
+
+    private long accountId;
+
+    public RtpSessionViewModel(@NonNull Application application) {
+        super(application);
+    }
+
+    public void setAccountId(
+            final long accountId, final Consumer<JingleConnectionManager> jmcConsumer) {
+        this.accountId = accountId;
+        this.connectJingleConnectionManager(accountId, jmcConsumer);
+    }
+
+    private void connectJingleConnectionManager(
+            long accountId, final Consumer<JingleConnectionManager> jmcConsumer) {
+        final var connectionFuture = ConnectionPool.getInstance(getApplication()).get(accountId);
+        final var jcmFuture =
+                Futures.transform(
+                        connectionFuture,
+                        connection -> connection.getManager(JingleConnectionManager.class),
+                        MoreExecutors.directExecutor());
+        Futures.addCallback(
+                jcmFuture,
+                new FutureCallback<>() {
+                    @Override
+                    public void onSuccess(JingleConnectionManager manager) {
+                        jmcConsumer.accept(manager);
+                    }
+
+                    @Override
+                    public void onFailure(Throwable t) {
+                        // TODO show warning in activity
+                    }
+                },
+                MoreExecutors.directExecutor());
+    }
+}

app/src/main/java/im/conversations/android/ui/widget/SurfaceViewRenderer.java

@@ -0,0 +1,55 @@
+package im.conversations.android.ui.widget;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.util.Rational;
+import eu.siacs.conversations.Config;
+
+public class SurfaceViewRenderer extends org.webrtc.SurfaceViewRenderer {
+
+    private Rational aspectRatio = new Rational(1, 1);
+
+    private OnAspectRatioChanged onAspectRatioChanged;
+
+    public SurfaceViewRenderer(Context context) {
+        super(context);
+    }
+
+    public SurfaceViewRenderer(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public void onFrameResolutionChanged(int videoWidth, int videoHeight, int rotation) {
+        super.onFrameResolutionChanged(videoWidth, videoHeight, rotation);
+        final int rotatedWidth = rotation != 0 && rotation != 180 ? videoHeight : videoWidth;
+        final int rotatedHeight = rotation != 0 && rotation != 180 ? videoWidth : videoHeight;
+        final Rational currentRational = this.aspectRatio;
+        this.aspectRatio = new Rational(rotatedWidth, rotatedHeight);
+        Log.d(
+                Config.LOGTAG,
+                "onFrameResolutionChanged("
+                        + rotatedWidth
+                        + ","
+                        + rotatedHeight
+                        + ","
+                        + aspectRatio
+                        + ")");
+        if (currentRational.equals(this.aspectRatio) || onAspectRatioChanged == null) {
+            return;
+        }
+        onAspectRatioChanged.onAspectRatioChanged(this.aspectRatio);
+    }
+
+    public void setOnAspectRatioChanged(final OnAspectRatioChanged onAspectRatioChanged) {
+        this.onAspectRatioChanged = onAspectRatioChanged;
+    }
+
+    public Rational getAspectRatio() {
+        return this.aspectRatio;
+    }
+
+    public interface OnAspectRatioChanged {
+        void onAspectRatioChanged(final Rational rational);
+    }
+}

app/src/main/java/im/conversations/android/util/MainThreadExecutor.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2019 Daniel Gultsch
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package im.conversations.android.util;
+
+import android.os.Handler;
+import android.os.Looper;
+import java.util.concurrent.Executor;
+
+public class MainThreadExecutor implements Executor {
+
+    private static final MainThreadExecutor INSTANCE = new MainThreadExecutor();
+
+    private final Handler handler = new Handler(Looper.myLooper());
+
+    @Override
+    public void execute(final Runnable command) {
+        handler.post(command);
+    }
+
+    public static MainThreadExecutor getInstance() {
+        return INSTANCE;
+    }
+}

app/src/main/java/im/conversations/android/util/PermissionUtils.java

@@ -0,0 +1,91 @@
+package im.conversations.android.util;
+
+import android.Manifest;
+import android.app.Activity;
+import android.content.pm.PackageManager;
+import android.os.Build;
+import androidx.core.app.ActivityCompat;
+import com.google.common.collect.ImmutableList;
+import com.google.common.primitives.Ints;
+import java.util.ArrayList;
+import java.util.List;
+
+public class PermissionUtils {
+
+    public static boolean allGranted(int[] grantResults) {
+        for (int grantResult : grantResults) {
+            if (grantResult != PackageManager.PERMISSION_GRANTED) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static boolean writeGranted(int[] grantResults, String[] permission) {
+        for (int i = 0; i < grantResults.length; ++i) {
+            if (Manifest.permission.WRITE_EXTERNAL_STORAGE.equals(permission[i])) {
+                return grantResults[i] == PackageManager.PERMISSION_GRANTED;
+            }
+        }
+        return false;
+    }
+
+    public static String getFirstDenied(int[] grantResults, String[] permissions) {
+        for (int i = 0; i < grantResults.length; ++i) {
+            if (grantResults[i] == PackageManager.PERMISSION_DENIED) {
+                return permissions[i];
+            }
+        }
+        return null;
+    }
+
+    public static class PermissionResult {
+        public final String[] permissions;
+        public final int[] grantResults;
+
+        public PermissionResult(String[] permissions, int[] grantResults) {
+            this.permissions = permissions;
+            this.grantResults = grantResults;
+        }
+    }
+
+    public static PermissionResult removeBluetoothConnect(
+            final String[] inPermissions, final int[] inGrantResults) {
+        final List<String> outPermissions = new ArrayList<>();
+        final List<Integer> outGrantResults = new ArrayList<>();
+        for (int i = 0; i < Math.min(inPermissions.length, inGrantResults.length); ++i) {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+                if (inPermissions[i].equals(Manifest.permission.BLUETOOTH_CONNECT)) {
+                    continue;
+                }
+            }
+            outPermissions.add(inPermissions[i]);
+            outGrantResults.add(inGrantResults[i]);
+        }
+
+        return new PermissionResult(
+                outPermissions.toArray(new String[0]), Ints.toArray(outGrantResults));
+    }
+
+    public static boolean hasPermission(
+            final Activity activity, final List<String> permissions, final int requestCode) {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+            final ImmutableList.Builder<String> missingPermissions = new ImmutableList.Builder<>();
+            for (final String permission : permissions) {
+                if (ActivityCompat.checkSelfPermission(activity, permission)
+                        != PackageManager.PERMISSION_GRANTED) {
+                    missingPermissions.add(permission);
+                }
+            }
+            final ImmutableList<String> missing = missingPermissions.build();
+            if (missing.size() == 0) {
+                return true;
+            }
+            ActivityCompat.requestPermissions(
+                    activity, missing.toArray(new String[0]), requestCode);
+            return false;
+        } else {
+            return true;
+        }
+    }
+}

app/src/main/java/im/conversations/android/util/Rationals.java

@@ -0,0 +1,22 @@
+package im.conversations.android.util;
+
+import android.util.Rational;
+
+public final class Rationals {
+
+    // between 2.39:1 and 1:2.39 (inclusive).
+    private static final Rational MIN = new Rational(100, 239);
+    private static final Rational MAX = new Rational(239, 100);
+
+    private Rationals() {}
+
+    public static Rational clip(final Rational input) {
+        if (input.compareTo(MIN) < 0) {
+            return MIN;
+        }
+        if (input.compareTo(MAX) > 0) {
+            return MAX;
+        }
+        return input;
+    }
+}

app/src/main/java/im/conversations/android/util/TimeFrameUtils.java

@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2018, Daniel Gultsch All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without modification,
+ * are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation and/or
+ * other materials provided with the distribution.
+ *
+ * 3. Neither the name of the copyright holder nor the names of its contributors
+ * may be used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+package im.conversations.android.util;
+
+import android.content.Context;
+import android.os.SystemClock;
+import androidx.annotation.PluralsRes;
+import im.conversations.android.R;
+import java.util.Locale;
+
+public class TimeFrameUtils {
+
+    private static final TimeFrame[] TIME_FRAMES;
+
+    static {
+        TIME_FRAMES =
+                new TimeFrame[] {
+                    new TimeFrame(1000L, R.plurals.seconds),
+                    new TimeFrame(60L * 1000, R.plurals.minutes),
+                    new TimeFrame(60L * 60 * 1000, R.plurals.hours),
+                    new TimeFrame(24L * 60 * 60 * 1000, R.plurals.days),
+                    new TimeFrame(7L * 24 * 60 * 60 * 1000, R.plurals.weeks),
+                    new TimeFrame(30L * 24 * 60 * 60 * 1000, R.plurals.months),
+                };
+    }
+
+    public static String resolve(Context context, long timeFrame) {
+        for (int i = TIME_FRAMES.length - 1; i >= 0; --i) {
+            long duration = TIME_FRAMES[i].duration;
+            long threshold = i > 0 ? (TIME_FRAMES[i - 1].duration / 2) : 0;
+            if (timeFrame >= duration - threshold) {
+                int count =
+                        (int)
+                                (timeFrame / duration
+                                        + ((timeFrame % duration) > (duration / 2) ? 1 : 0));
+                return context.getResources().getQuantityString(TIME_FRAMES[i].name, count, count);
+            }
+        }
+        return context.getResources().getQuantityString(TIME_FRAMES[0].name, 0, 0);
+    }
+
+    public static String formatTimePassed(final long since, final boolean withMilliseconds) {
+        return formatTimePassed(since, SystemClock.elapsedRealtime(), withMilliseconds);
+    }
+
+    public static String formatTimePassed(
+            final long since, final long to, final boolean withMilliseconds) {
+        final long passed = (since < 0) ? 0 : (to - since);
+        return formatElapsedTime(passed, withMilliseconds);
+    }
+
+    public static String formatElapsedTime(final long elapsed, final boolean withMilliseconds) {
+        final int hours = (int) (elapsed / 3600000);
+        final int minutes = (int) (elapsed / 60000) % 60;
+        final int seconds = (int) (elapsed / 1000) % 60;
+        final int milliseconds = (int) (elapsed / 100) % 10;
+        if (hours > 0) {
+            return String.format(Locale.ENGLISH, "%d:%02d:%02d", hours, minutes, seconds);
+        } else if (withMilliseconds) {
+            return String.format(Locale.ENGLISH, "%d:%02d.%d", minutes, seconds, milliseconds);
+        } else {
+            return String.format(Locale.ENGLISH, "%d:%02d", minutes, seconds);
+        }
+    }
+
+    private static class TimeFrame {
+        final long duration;
+        public final int name;
+
+        private TimeFrame(long duration, @PluralsRes int name) {
+            this.duration = duration;
+            this.name = name;
+        }
+    }
+}

app/src/main/java/im/conversations/android/xml/Element.java

@@ -155,6 +155,10 @@ public class Element {
         return this.setAttribute(name, value == null ? null : value.toString());
     }
 
+    public void setAttribute(final String name, final boolean value) {
+        this.setAttribute(name, value ? "1" : "0");
+    }
+
     public void removeAttribute(final String name) {
         this.attributes.remove(name);
     }

app/src/main/java/im/conversations/android/xmpp/Managers.java

@@ -12,6 +12,7 @@ import im.conversations.android.xmpp.manager.BookmarkManager;
 import im.conversations.android.xmpp.manager.CarbonsManager;
 import im.conversations.android.xmpp.manager.ChatStateManager;
 import im.conversations.android.xmpp.manager.DiscoManager;
+import im.conversations.android.xmpp.manager.ExternalDiscoManager;
 import im.conversations.android.xmpp.manager.HttpUploadManager;
 import im.conversations.android.xmpp.manager.JingleConnectionManager;
 import im.conversations.android.xmpp.manager.NickManager;
@@ -38,6 +39,7 @@ public final class Managers {
                 .put(CarbonsManager.class, new CarbonsManager(context, connection))
                 .put(ChatStateManager.class, new ChatStateManager(context, connection))
                 .put(DiscoManager.class, new DiscoManager(context, connection))
+                .put(ExternalDiscoManager.class, new ExternalDiscoManager(context, connection))
                 .put(HttpUploadManager.class, new HttpUploadManager(context, connection))
                 .put(
                         JingleConnectionManager.class,

app/src/main/java/im/conversations/android/xmpp/XmppConnection.java

@@ -17,6 +17,7 @@ import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
 import com.google.common.util.concurrent.SettableFuture;
+import im.conversations.android.AbstractAccountService;
 import im.conversations.android.BuildConfig;
 import im.conversations.android.Conversations;
 import im.conversations.android.IDs;
@@ -105,17 +106,15 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.xmlpull.v1.XmlPullParserException;
 
-public class XmppConnection implements Runnable {
+public class XmppConnection extends AbstractAccountService implements Runnable {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(XmppConnection.class);
 
     private static final boolean EXTENDED_SM_LOGGING = false;
     private static final int CONNECT_DISCO_TIMEOUT = 20;
 
-    protected final Account account;
     private final SparseArray<Stanza> mStanzaQueue = new SparseArray<>();
     private final Hashtable<String, Pair<Iq, Consumer<Iq>>> packetCallbacks = new Hashtable<>();
-    private final Context context;
     private Socket socket;
     private XmlReader tagReader;
     private TagWriter tagWriter = new TagWriter();
@@ -156,8 +155,7 @@ public class XmppConnection implements Runnable {
     private CountDownLatch mStreamCountDownLatch;
 
     public XmppConnection(final Context context, final Account account) {
-        this.context = context;
-        this.account = account;
+        super(context, account);
         this.connectionAddress = account.address;
 
         // these consumers are pure listeners; they don’t have public method except for accept|apply

app/src/main/java/im/conversations/android/xmpp/manager/AxolotlManager.java

@@ -2,23 +2,39 @@ package im.conversations.android.xmpp.manager;
 
 import android.content.Context;
 import androidx.annotation.NonNull;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.util.concurrent.FutureCallback;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListenableFuture;
 import com.google.common.util.concurrent.MoreExecutors;
-import im.conversations.android.database.AxolotlDatabaseStore;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.xmpp.jingle.OmemoVerification;
+import eu.siacs.conversations.xmpp.jingle.OmemoVerifiedRtpContentMap;
+import eu.siacs.conversations.xmpp.jingle.RtpContentMap;
+import eu.siacs.conversations.xmpp.jingle.stanzas.IceUdpTransportInfo;
+import eu.siacs.conversations.xmpp.jingle.stanzas.OmemoVerifiedIceUdpTransportInfo;
+import im.conversations.android.axolotl.AxolotlAddress;
+import im.conversations.android.axolotl.AxolotlDecryptionException;
+import im.conversations.android.axolotl.AxolotlEncryptionException;
+import im.conversations.android.axolotl.AxolotlPayload;
+import im.conversations.android.axolotl.AxolotlService;
+import im.conversations.android.axolotl.AxolotlSession;
+import im.conversations.android.axolotl.EncryptionBuilder;
+import im.conversations.android.xml.Element;
 import im.conversations.android.xml.Namespace;
 import im.conversations.android.xmpp.IqErrorException;
 import im.conversations.android.xmpp.NodeConfiguration;
 import im.conversations.android.xmpp.XmppConnection;
-import im.conversations.android.xmpp.axolotl.AxolotlAddress;
 import im.conversations.android.xmpp.model.axolotl.Bundle;
 import im.conversations.android.xmpp.model.axolotl.DeviceList;
+import im.conversations.android.xmpp.model.axolotl.Encrypted;
 import im.conversations.android.xmpp.model.pubsub.Items;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.Locale;
+import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeoutException;
 import org.jxmpp.jid.BareJid;
@@ -28,7 +44,6 @@ import org.slf4j.LoggerFactory;
 import org.whispersystems.libsignal.IdentityKey;
 import org.whispersystems.libsignal.InvalidKeyException;
 import org.whispersystems.libsignal.SessionBuilder;
-import org.whispersystems.libsignal.SessionCipher;
 import org.whispersystems.libsignal.UntrustedIdentityException;
 import org.whispersystems.libsignal.state.PreKeyBundle;
 import org.whispersystems.libsignal.state.SignalProtocolStore;
@@ -41,11 +56,11 @@ public class AxolotlManager extends AbstractManager {
 
     private static final int NUM_PRE_KEYS_IN_BUNDLE = 30;
 
-    private final SignalProtocolStore signalProtocolStore;
+    private final AxolotlService axolotlService;
 
     public AxolotlManager(Context context, XmppConnection connection) {
         super(context, connection);
-        this.signalProtocolStore = new AxolotlDatabaseStore(context, connection.getAccount());
+        this.axolotlService = new AxolotlService(context, connection.getAccount());
     }
 
     public void handleItems(final BareJid from, final Items items) {
@@ -103,25 +118,27 @@ public class AxolotlManager extends AbstractManager {
         return getManager(PubSubManager.class).fetchMostRecentItem(address, node, Bundle.class);
     }
 
-    public ListenableFuture<SessionCipher> getOrCreateSessionCipher(
+    public ListenableFuture<AxolotlSession> getOrCreateSessionCipher(
             final AxolotlAddress axolotlAddress) {
-        if (signalProtocolStore.containsSession(axolotlAddress)) {
-            return Futures.immediateFuture(new SessionCipher(signalProtocolStore, axolotlAddress));
+        final AxolotlSession session = axolotlService.getExistingSession(axolotlAddress);
+        if (session != null) {
+            return Futures.immediateFuture(session);
         } else {
             final var bundleFuture =
                     fetchBundle(axolotlAddress.getJid(), axolotlAddress.getDeviceId());
             return Futures.transform(
                     bundleFuture,
                     bundle -> {
-                        buildSession(axolotlAddress, bundle);
-                        return new SessionCipher(signalProtocolStore, axolotlAddress);
+                        final var identityKey = buildSession(axolotlAddress, bundle);
+                        return AxolotlSession.of(
+                                signalProtocolStore(), identityKey, axolotlAddress);
                     },
                     MoreExecutors.directExecutor());
         }
     }
 
-    private void buildSession(final AxolotlAddress address, final Bundle bundle) {
-        final var sessionBuilder = new SessionBuilder(signalProtocolStore, address);
+    private IdentityKey buildSession(final AxolotlAddress address, final Bundle bundle) {
+        final var sessionBuilder = new SessionBuilder(signalProtocolStore(), address);
         final var deviceId = address.getDeviceId();
         final var preKey = bundle.getRandomPreKey();
         final var signedPreKey = bundle.getSignedPreKey();
@@ -139,6 +156,7 @@ public class AxolotlManager extends AbstractManager {
         if (identityKey == null) {
             throw new IllegalArgumentException("No IdentityKey found in bundle");
         }
+        final var signalIdentityKey = new IdentityKey(identityKey.asECPublicKey());
         final var preKeyBundle =
                 new PreKeyBundle(
                         0,
@@ -148,9 +166,10 @@ public class AxolotlManager extends AbstractManager {
                         signedPreKey.getId(),
                         signedPreKey.asECPublicKey(),
                         signedPreKeySignature.asBytes(),
-                        new IdentityKey(identityKey.asECPublicKey()));
+                        signalIdentityKey);
         try {
             sessionBuilder.process(preKeyBundle);
+            return signalIdentityKey;
         } catch (final InvalidKeyException | UntrustedIdentityException e) {
             throw new RuntimeException(e);
         }
@@ -249,7 +268,7 @@ public class AxolotlManager extends AbstractManager {
                                     Locale.ROOT,
                                     "%s:%d",
                                     Namespace.AXOLOTL_BUNDLES,
-                                    signalProtocolStore.getLocalRegistrationId());
+                                    signalProtocolStore().getLocalRegistrationId());
                     return getManager(PepManager.class)
                             .publishSingleton(bundle, node, NodeConfiguration.OPEN);
                 },
@@ -260,7 +279,7 @@ public class AxolotlManager extends AbstractManager {
         refillPreKeys();
         final var bundle = new Bundle();
         bundle.setIdentityKey(
-                signalProtocolStore.getIdentityKeyPair().getPublicKey().getPublicKey());
+                signalProtocolStore().getIdentityKeyPair().getPublicKey().getPublicKey());
         final var signedPreKeyRecord =
                 getDatabase().axolotlDao().getLatestSignedPreKey(getAccount().id);
         if (signedPreKeyRecord == null) {
@@ -286,11 +305,11 @@ public class AxolotlManager extends AbstractManager {
             try {
                 signedPreKeyRecord =
                         KeyHelper.generateSignedPreKey(
-                                signalProtocolStore.getIdentityKeyPair(), signedPreKeyId);
+                                signalProtocolStore().getIdentityKeyPair(), signedPreKeyId);
             } catch (final InvalidKeyException e) {
                 throw new IllegalStateException("Could not generate SignedPreKey", e);
             }
-            signalProtocolStore.storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
+            signalProtocolStore().storeSignedPreKey(signedPreKeyRecord.getId(), signedPreKeyRecord);
             LOGGER.info("Generated SignedPreKey #{}", signedPreKeyRecord.getId());
         }
         axolotlDao.setPreKeys(getAccount(), preKeys);
@@ -298,4 +317,165 @@ public class AxolotlManager extends AbstractManager {
             LOGGER.info("Generated {} PreKeys starting with {}", preKeys.size(), start);
         }
     }
+
+    private OmemoVerifiedIceUdpTransportInfo encrypt(
+            final IceUdpTransportInfo element, final AxolotlSession session)
+            throws AxolotlEncryptionException {
+        final OmemoVerifiedIceUdpTransportInfo transportInfo =
+                new OmemoVerifiedIceUdpTransportInfo();
+        transportInfo.setAttributes(element.getAttributes());
+        for (final Element child : element.getChildren()) {
+            if ("fingerprint".equals(child.getName())
+                    && Namespace.JINGLE_APPS_DTLS.equals(child.getNamespace())) {
+                final Element fingerprint =
+                        new Element("fingerprint", Namespace.OMEMO_DTLS_SRTP_VERIFICATION);
+                fingerprint.setAttribute("setup", child.getAttribute("setup"));
+                fingerprint.setAttribute("hash", child.getAttribute("hash"));
+                final String content = child.getContent();
+                final var encrypted =
+                        new EncryptionBuilder()
+                                .sourceDeviceId(signalProtocolStore().getLocalRegistrationId())
+                                .payload(content)
+                                .session(session)
+                                .build();
+                fingerprint.addExtension(encrypted);
+                transportInfo.addChild(fingerprint);
+            } else {
+                transportInfo.addChild(child);
+            }
+        }
+        return transportInfo;
+    }
+
+    public ListenableFuture<AxolotlService.OmemoVerifiedPayload<OmemoVerifiedRtpContentMap>>
+            encrypt(final RtpContentMap rtpContentMap, final Jid jid, final int deviceId) {
+        final var axolotlAddress = new AxolotlAddress(jid.asBareJid(), deviceId);
+        final var sessionFuture = getOrCreateSessionCipher(axolotlAddress);
+        return Futures.transformAsync(
+                sessionFuture,
+                session -> encrypt(rtpContentMap, session),
+                MoreExecutors.directExecutor());
+    }
+
+    private ListenableFuture<AxolotlService.OmemoVerifiedPayload<OmemoVerifiedRtpContentMap>>
+            encrypt(final RtpContentMap rtpContentMap, final AxolotlSession session) {
+        if (Config.REQUIRE_RTP_VERIFICATION) {
+            requireVerification(session);
+        }
+        final ImmutableMap.Builder<String, RtpContentMap.DescriptionTransport>
+                descriptionTransportBuilder = new ImmutableMap.Builder<>();
+        final OmemoVerification omemoVerification = new OmemoVerification();
+        omemoVerification.setDeviceId(session.axolotlAddress.getDeviceId());
+        omemoVerification.setSessionFingerprint(session.identityKey);
+        for (final Map.Entry<String, RtpContentMap.DescriptionTransport> content :
+                rtpContentMap.contents.entrySet()) {
+            final RtpContentMap.DescriptionTransport descriptionTransport = content.getValue();
+            final OmemoVerifiedIceUdpTransportInfo encryptedTransportInfo;
+            try {
+                encryptedTransportInfo = encrypt(descriptionTransport.transport, session);
+            } catch (final AxolotlEncryptionException e) {
+                return Futures.immediateFailedFuture(e);
+            }
+            descriptionTransportBuilder.put(
+                    content.getKey(),
+                    new RtpContentMap.DescriptionTransport(
+                            descriptionTransport.senders,
+                            descriptionTransport.description,
+                            encryptedTransportInfo));
+        }
+        return Futures.immediateFuture(
+                new AxolotlService.OmemoVerifiedPayload<>(
+                        omemoVerification,
+                        new OmemoVerifiedRtpContentMap(
+                                rtpContentMap.group, descriptionTransportBuilder.build())));
+    }
+
+    public ListenableFuture<AxolotlService.OmemoVerifiedPayload<RtpContentMap>> decrypt(
+            OmemoVerifiedRtpContentMap omemoVerifiedRtpContentMap, final Jid from) {
+        final ImmutableMap.Builder<String, RtpContentMap.DescriptionTransport>
+                descriptionTransportBuilder = new ImmutableMap.Builder<>();
+        final OmemoVerification omemoVerification = new OmemoVerification();
+        final ImmutableList.Builder<ListenableFuture<AxolotlSession>> pepVerificationFutures =
+                new ImmutableList.Builder<>();
+        for (final Map.Entry<String, RtpContentMap.DescriptionTransport> content :
+                omemoVerifiedRtpContentMap.contents.entrySet()) {
+            final RtpContentMap.DescriptionTransport descriptionTransport = content.getValue();
+            final AxolotlService.OmemoVerifiedPayload<IceUdpTransportInfo> decryptedTransport;
+            try {
+                decryptedTransport =
+                        decrypt(
+                                (OmemoVerifiedIceUdpTransportInfo) descriptionTransport.transport,
+                                from,
+                                pepVerificationFutures);
+            } catch (final AxolotlDecryptionException e) {
+                return Futures.immediateFailedFuture(e);
+            }
+            omemoVerification.setOrEnsureEqual(decryptedTransport);
+            descriptionTransportBuilder.put(
+                    content.getKey(),
+                    new RtpContentMap.DescriptionTransport(
+                            descriptionTransport.senders,
+                            descriptionTransport.description,
+                            decryptedTransport.getPayload()));
+        }
+        final ImmutableList<ListenableFuture<AxolotlSession>> sessionFutures =
+                pepVerificationFutures.build();
+        return Futures.transform(
+                Futures.allAsList(sessionFutures),
+                sessions -> {
+                    if (Config.REQUIRE_RTP_VERIFICATION) {
+                        for (final AxolotlSession session : sessions) {
+                            requireVerification(session);
+                        }
+                    }
+                    return new AxolotlService.OmemoVerifiedPayload<>(
+                            omemoVerification,
+                            new RtpContentMap(
+                                    omemoVerifiedRtpContentMap.group,
+                                    descriptionTransportBuilder.build()));
+                },
+                MoreExecutors.directExecutor());
+    }
+
+    private AxolotlService.OmemoVerifiedPayload<IceUdpTransportInfo> decrypt(
+            final OmemoVerifiedIceUdpTransportInfo verifiedIceUdpTransportInfo,
+            final Jid from,
+            ImmutableList.Builder<ListenableFuture<AxolotlSession>> pepVerificationFutures)
+            throws AxolotlDecryptionException {
+        final IceUdpTransportInfo transportInfo = new IceUdpTransportInfo();
+        transportInfo.setAttributes(verifiedIceUdpTransportInfo.getAttributes());
+        final OmemoVerification omemoVerification = new OmemoVerification();
+        for (final Element child : verifiedIceUdpTransportInfo.getChildren()) {
+            if ("fingerprint".equals(child.getName())
+                    && Namespace.OMEMO_DTLS_SRTP_VERIFICATION.equals(child.getNamespace())) {
+                final Element fingerprint = new Element("fingerprint", Namespace.JINGLE_APPS_DTLS);
+                fingerprint.setAttribute("setup", child.getAttribute("setup"));
+                fingerprint.setAttribute("hash", child.getAttribute("hash"));
+                final Encrypted encrypted = child.getExtension(Encrypted.class);
+                final AxolotlPayload axolotlPayload = axolotlService.decrypt(from, encrypted);
+                fingerprint.setContent(axolotlPayload.payloadAsString());
+                omemoVerification.setDeviceId(axolotlPayload.axolotlAddress.getDeviceId());
+                omemoVerification.setSessionFingerprint(axolotlPayload.identityKey);
+                transportInfo.addChild(fingerprint);
+            } else {
+                transportInfo.addChild(child);
+            }
+        }
+        return new AxolotlService.OmemoVerifiedPayload<>(omemoVerification, transportInfo);
+    }
+
+    private static void requireVerification(final AxolotlSession session) {
+        // TODO fix me; check if identity key is trusted
+
+        /*if (session.getTrust().isVerified()) {
+            return;
+        }*/
+        throw new AxolotlService.NotVerifiedException(
+                String.format(
+                        "session with %s was not verified", session.identityKey.getFingerprint()));
+    }
+
+    private SignalProtocolStore signalProtocolStore() {
+        return this.axolotlService.getSignalProtocolStore();
+    }
 }

app/src/main/java/im/conversations/android/xmpp/manager/DiscoManager.java

@@ -32,7 +32,6 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.List;
 import java.util.Objects;
-import org.jxmpp.jid.Jid;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -67,8 +66,8 @@ public class DiscoManager extends AbstractManager {
                     Namespace.JINGLE_FEATURE_AUDIO,
                     Namespace.JINGLE_FEATURE_VIDEO,
                     Namespace.JINGLE_APPS_RTP,
-                    Namespace.JINGLE_APPS_DTLS,
-                    Namespace.JINGLE_MESSAGE);
+                    Namespace.JINGLE_APPS_DTLS /*,
+                    Namespace.JINGLE_MESSAGE*/);
 
     private static final Collection<String> FEATURES_IMPACTING_PRIVACY =
             Collections.singleton(Namespace.VERSION);
@@ -241,16 +240,28 @@ public class DiscoManager extends AbstractManager {
                 MoreExecutors.directExecutor());
     }
 
-    public boolean hasFeature(final Jid entity, final String feature) {
+    public boolean hasFeature(final Entity entity, final String feature) {
         return getDatabase().discoDao().hasFeature(getAccount().id, entity, feature);
     }
 
+    public ListenableFuture<Boolean> hasFeatureAsync(final Entity entity, final String feature) {
+        return Futures.submit(() -> hasFeature(entity, feature), getDatabase().getQueryExecutor());
+    }
+
     public boolean hasAccountFeature(final String feature) {
-        return hasFeature(getAccount().address, feature);
+        return hasFeature(Entity.discoItem(getAccount().address), feature);
+    }
+
+    public ListenableFuture<Boolean> hasAccountFeatureAsync(final String feature) {
+        return Futures.submit(() -> hasAccountFeature(feature), getDatabase().getQueryExecutor());
     }
 
     public boolean hasServerFeature(final String feature) {
-        return hasFeature(getAccount().address.asDomainBareJid(), feature);
+        return hasFeature(Entity.discoItem(getAccount().address.asDomainBareJid()), feature);
+    }
+
+    public ListenableFuture<Boolean> hasServerFeatureAsync(final String feature) {
+        return Futures.submit(() -> hasServerFeature(feature), getDatabase().getQueryExecutor());
     }
 
     public ServiceDescription getServiceDescription() {

app/src/main/java/im/conversations/android/xmpp/manager/ExternalDiscoManager.java

@@ -0,0 +1,55 @@
+package im.conversations.android.xmpp.manager;
+
+import android.content.Context;
+import com.google.common.util.concurrent.Futures;
+import com.google.common.util.concurrent.ListenableFuture;
+import com.google.common.util.concurrent.MoreExecutors;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import im.conversations.android.xml.Namespace;
+import im.conversations.android.xmpp.XmppConnection;
+import im.conversations.android.xmpp.model.disco.external.Service;
+import im.conversations.android.xmpp.model.disco.external.Services;
+import im.conversations.android.xmpp.model.stanza.Iq;
+import java.util.Collection;
+
+public class ExternalDiscoManager extends AbstractManager {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(ExternalDiscoManager.class);
+
+    public ExternalDiscoManager(Context context, XmppConnection connection) {
+        super(context, connection);
+    }
+
+    public ListenableFuture<Collection<Service>> getServices() {
+        final var hasFeatureFuture =
+                getManager(DiscoManager.class)
+                        .hasServerFeatureAsync(Namespace.EXTERNAL_SERVICE_DISCOVERY);
+        final var iqResultFuture =
+                Futures.transformAsync(
+                        hasFeatureFuture,
+                        hasFeature -> {
+                            if (Boolean.TRUE.equals(hasFeature)) {
+                                final Iq request = new Iq(Iq.Type.GET);
+                                request.setTo(getAccount().address.asDomainBareJid());
+                                request.addExtension(new Services());
+                                return connection.sendIqPacket(request);
+                            }
+                            throw new IllegalStateException(
+                                    "Server does not support External Service Discovery");
+                        },
+                        MoreExecutors.directExecutor());
+        return Futures.transform(
+                iqResultFuture,
+                result -> {
+                    final var services = result.getExtension(Services.class);
+                    if (services == null) {
+                        throw new IllegalStateException("Server result did not contain services");
+                    }
+                    return services.getExtensions(Service.class);
+                },
+                MoreExecutors.directExecutor());
+    }
+}

app/src/main/java/im/conversations/android/xmpp/manager/JingleConnectionManager.java

@@ -1,16 +1,880 @@
 package im.conversations.android.xmpp.manager;
 
 import android.content.Context;
-
+import android.util.Log;
+import com.google.common.base.Objects;
+import com.google.common.base.Optional;
+import com.google.common.base.Strings;
+import com.google.common.cache.Cache;
+import com.google.common.cache.CacheBuilder;
+import com.google.common.collect.Collections2;
+import com.google.common.collect.ComparisonChain;
+import com.google.common.collect.ImmutableSet;
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.generator.MessageGenerator;
+import eu.siacs.conversations.services.AppRTCAudioManager;
+import eu.siacs.conversations.xmpp.jingle.AbstractJingleConnection;
+import eu.siacs.conversations.xmpp.jingle.JingleRtpConnection;
+import eu.siacs.conversations.xmpp.jingle.Media;
+import eu.siacs.conversations.xmpp.jingle.OngoingRtpSession;
+import eu.siacs.conversations.xmpp.jingle.RtpEndUserState;
+import eu.siacs.conversations.xmpp.jingle.ToneManager;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Content;
+import eu.siacs.conversations.xmpp.jingle.stanzas.GenericDescription;
+import eu.siacs.conversations.xmpp.jingle.stanzas.JinglePacket;
+import eu.siacs.conversations.xmpp.jingle.stanzas.Reason;
+import eu.siacs.conversations.xmpp.jingle.stanzas.RtpDescription;
+import im.conversations.android.IDs;
+import im.conversations.android.database.model.Account;
+import im.conversations.android.notification.RtpSessionNotification;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
 import im.conversations.android.xmpp.XmppConnection;
+import im.conversations.android.xmpp.model.error.Condition;
+import im.conversations.android.xmpp.model.error.Error;
+import im.conversations.android.xmpp.model.jmi.Accept;
+import im.conversations.android.xmpp.model.jmi.JingleMessage;
+import im.conversations.android.xmpp.model.jmi.Proceed;
+import im.conversations.android.xmpp.model.jmi.Propose;
 import im.conversations.android.xmpp.model.stanza.Iq;
+import im.conversations.android.xmpp.model.stanza.Message;
+import java.lang.ref.WeakReference;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
+import org.jxmpp.jid.Jid;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 public class JingleConnectionManager extends AbstractManager {
-    public JingleConnectionManager(Context context, XmppConnection connection) {
+
+    private static final Logger LOGGER = LoggerFactory.getLogger(JingleConnectionManager.class);
+
+    public static final ScheduledExecutorService SCHEDULED_EXECUTOR_SERVICE =
+            Executors.newSingleThreadScheduledExecutor();
+    private final HashMap<RtpSessionProposal, DeviceDiscoveryState> rtpSessionProposals =
+            new HashMap<>();
+    private final ConcurrentHashMap<AbstractJingleConnection.Id, AbstractJingleConnection>
+            connections = new ConcurrentHashMap<>();
+
+    private final Cache<PersistableSessionId, TerminatedRtpSession> terminatedSessions =
+            CacheBuilder.newBuilder().expireAfterWrite(24, TimeUnit.HOURS).build();
+
+    private final RtpSessionNotification rtpSessionNotification;
+
+    private OnJingleRtpConnectionUpdate onJingleRtpConnectionUpdate;
+
+    public JingleConnectionManager(final Context context, final XmppConnection connection) {
         super(context, connection);
+        this.rtpSessionNotification = new RtpSessionNotification(context);
     }
 
-    public void handleJingle(Iq packet) {
+    @Override
+    public Account getAccount() {
+        return super.getAccount();
+    }
 
+    public void handleJingle(final Iq iq) {
+        final JinglePacket packet = JinglePacket.upgrade(iq);
+        final String sessionId = packet.getSessionId();
+        if (sessionId == null) {
+            respondWithJingleError(
+                    iq, "unknown-session", Error.Type.CANCEL, new Condition.ItemNotFound());
+            return;
+        }
+        final AbstractJingleConnection.Id id = AbstractJingleConnection.Id.of(packet);
+        final AbstractJingleConnection existingJingleConnection = connections.get(id);
+        if (existingJingleConnection != null) {
+            existingJingleConnection.deliverPacket(packet);
+        } else if (packet.getAction() == JinglePacket.Action.SESSION_INITIATE) {
+            final Jid from = packet.getFrom();
+            final Content content = packet.getJingleContent();
+            final String descriptionNamespace =
+                    content == null ? null : content.getDescriptionNamespace();
+            final AbstractJingleConnection connection;
+            if (Namespace.JINGLE_APPS_RTP.equals(descriptionNamespace) && isUsingClearNet()) {
+                final boolean sessionEnded =
+                        this.terminatedSessions.asMap().containsKey(PersistableSessionId.of(id));
+                final boolean stranger = isWithStrangerAndStrangerNotificationsAreOff(id.with);
+                if (isBusy() || sessionEnded || stranger) {
+                    LOGGER.debug(
+                            this.connection.getAccount().address
+                                    + ": rejected session with "
+                                    + id.with
+                                    + " because busy. sessionEnded="
+                                    + sessionEnded
+                                    + ", stranger="
+                                    + stranger);
+                    this.connection.sendResultFor(packet);
+                    final JinglePacket sessionTermination =
+                            new JinglePacket(JinglePacket.Action.SESSION_TERMINATE, id.sessionId);
+                    sessionTermination.setTo(id.with);
+                    sessionTermination.setReason(Reason.BUSY, null);
+                    this.connection.sendIqPacket(sessionTermination, null);
+                    return;
+                }
+                connection = new JingleRtpConnection(context, this.connection, id, from);
+            } else {
+                respondWithJingleError(
+                        packet,
+                        "unsupported-info",
+                        Error.Type.CANCEL,
+                        new Condition.FeatureNotImplemented());
+                return;
+            }
+            connections.put(id, connection);
+            connection.deliverPacket(packet);
+        } else {
+            Log.d(Config.LOGTAG, "unable to route jingle packet: " + packet);
+            respondWithJingleError(
+                    packet, "unknown-session", Error.Type.CANCEL, new Condition.ItemNotFound());
+        }
+    }
+
+    private boolean isUsingClearNet() {
+        // todo bring back proper Tor check
+        return !connection.getAccount().isOnion();
+    }
+
+    public boolean isBusy() {
+        // TODO check if in actual phone call
+        for (AbstractJingleConnection connection : this.connections.values()) {
+            if (connection instanceof JingleRtpConnection) {
+                if (((JingleRtpConnection) connection).isTerminated()) {
+                    continue;
+                }
+                return true;
+            }
+        }
+        synchronized (this.rtpSessionProposals) {
+            return this.rtpSessionProposals.containsValue(DeviceDiscoveryState.DISCOVERED)
+                    || this.rtpSessionProposals.containsValue(DeviceDiscoveryState.SEARCHING)
+                    || this.rtpSessionProposals.containsValue(
+                            JingleConnectionManager.DeviceDiscoveryState.SEARCHING_ACKNOWLEDGED);
+        }
+    }
+
+    public void notifyPhoneCallStarted() {
+        for (AbstractJingleConnection connection : connections.values()) {
+            if (connection instanceof JingleRtpConnection) {
+                final JingleRtpConnection rtpConnection = (JingleRtpConnection) connection;
+                if (rtpConnection.isTerminated()) {
+                    continue;
+                }
+                rtpConnection.notifyPhoneCall();
+            }
+        }
+    }
+
+    private Optional<RtpSessionProposal> findMatchingSessionProposal(
+            final Jid with, final Set<Media> media) {
+        synchronized (this.rtpSessionProposals) {
+            for (Map.Entry<RtpSessionProposal, DeviceDiscoveryState> entry :
+                    this.rtpSessionProposals.entrySet()) {
+                final RtpSessionProposal proposal = entry.getKey();
+                final DeviceDiscoveryState state = entry.getValue();
+                final boolean openProposal =
+                        state == DeviceDiscoveryState.DISCOVERED
+                                || state == DeviceDiscoveryState.SEARCHING
+                                || state == DeviceDiscoveryState.SEARCHING_ACKNOWLEDGED;
+                if (openProposal
+                        && proposal.with.equals(with.asBareJid())
+                        && proposal.media.equals(media)) {
+                    return Optional.of(proposal);
+                }
+            }
+        }
+        return Optional.absent();
+    }
+
+    private boolean hasMatchingRtpSession(final Jid with, final Set<Media> media) {
+        for (AbstractJingleConnection connection : this.connections.values()) {
+            if (connection instanceof JingleRtpConnection) {
+                final JingleRtpConnection rtpConnection = (JingleRtpConnection) connection;
+                if (rtpConnection.isTerminated()) {
+                    continue;
+                }
+                if (rtpConnection.getId().with.asBareJid().equals(with.asBareJid())
+                        && rtpConnection.getMedia().equals(media)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    private boolean isWithStrangerAndStrangerNotificationsAreOff(Jid with) {
+        final boolean notifyForStrangers = rtpSessionNotification.notificationsFromStrangers();
+        if (notifyForStrangers) {
+            return false;
+        }
+        return getDatabase().rosterDao().isInRoster(getAccount().id, with.asBareJid());
+    }
+
+    public ScheduledFuture<?> schedule(
+            final Runnable runnable, final long delay, final TimeUnit timeUnit) {
+        return SCHEDULED_EXECUTOR_SERVICE.schedule(runnable, delay, timeUnit);
+    }
+
+    private void respondWithJingleError(
+            final Iq original, String jingleCondition, final Error.Type type, Condition condition) {
+        // TODO add jingle condation
+        connection.sendErrorFor(original, type, condition);
+    }
+
+    public void deliverMessage(
+            final Jid to,
+            final Jid from,
+            final JingleMessage message,
+            final String remoteMsgId,
+            final String serverMsgId) {
+        final String sessionId = message.getSessionId();
+        if (Strings.isNullOrEmpty(sessionId)) {
+            return;
+        }
+        if (message instanceof Accept) {
+            for (AbstractJingleConnection connection : connections.values()) {
+                if (connection instanceof JingleRtpConnection) {
+                    final JingleRtpConnection rtpConnection = (JingleRtpConnection) connection;
+                    final AbstractJingleConnection.Id id = connection.getId();
+                    if (id.sessionId.equals(sessionId)) {
+                        rtpConnection.deliveryMessage(from, message, serverMsgId);
+                        return;
+                    }
+                }
+            }
+            return;
+        }
+        final boolean fromSelf = from.asBareJid().equals(connection.getBoundAddress().asBareJid());
+        final boolean addressedDirectly = to != null && to.equals(connection.getBoundAddress());
+        final AbstractJingleConnection.Id id;
+        if (fromSelf) {
+            if (to != null && to.hasResource()) {
+                id = AbstractJingleConnection.Id.of(to, sessionId);
+            } else {
+                return;
+            }
+        } else {
+            id = AbstractJingleConnection.Id.of(from, sessionId);
+        }
+        final AbstractJingleConnection existingJingleConnection = connections.get(id);
+        if (existingJingleConnection != null) {
+            if (existingJingleConnection instanceof JingleRtpConnection) {
+                ((JingleRtpConnection) existingJingleConnection)
+                        .deliveryMessage(from, message, serverMsgId);
+            } else {
+                LOGGER.debug(
+                        connection.getAccount().address
+                                + ": "
+                                + existingJingleConnection.getClass().getName()
+                                + " does not support jingle messages");
+            }
+            return;
+        }
+
+        if (fromSelf) {
+            if (message instanceof Proceed) {
+
+                // if we've previously rejected a call because we were busy (which would have
+                // created a CallLogEntry) but that call was picked up on another one of our devices
+                // we want to update that CallLogEntry to say picked up (not missed)
+
+                /*final Conversation c =
+                        mXmppConnectionService.findOrCreateConversation(
+                                account, id.with, false, false);
+                final Message previousBusy = c.findRtpSession(sessionId, Message.STATUS_RECEIVED);
+                if (previousBusy != null) {
+                    previousBusy.setBody(new RtpSessionStatus(true, 0).toString());
+                    if (serverMsgId != null) {
+                        previousBusy.setServerMsgId(serverMsgId);
+                    }
+                    previousBusy.setTime(timestamp);
+                    mXmppConnectionService.updateMessage(previousBusy, true);
+                    LOGGER.debug(
+                            connection.getAccount().address
+                                    + ": updated previous busy because call got picked up by another device");
+                    return;
+                }*/
+            }
+            // TODO handle reject for cases where we don’t have carbon copies (normally reject is to
+            // be sent to own bare jid as well)
+            LOGGER.debug(connection.getAccount().address + ": ignore jingle message from self");
+            return;
+        }
+
+        if (message instanceof Propose) {
+            final Propose propose = (Propose) message;
+            final List<GenericDescription> descriptions = propose.getDescriptions();
+            final Collection<RtpDescription> rtpDescriptions =
+                    Collections2.transform(
+                            Collections2.filter(descriptions, d -> d instanceof RtpDescription),
+                            input -> (RtpDescription) input);
+            if (rtpDescriptions.size() > 0
+                    && rtpDescriptions.size() == descriptions.size()
+                    && isUsingClearNet()) {
+                final Collection<Media> media =
+                        Collections2.transform(rtpDescriptions, RtpDescription::getMedia);
+                if (media.contains(Media.UNKNOWN)) {
+                    LOGGER.debug(
+                            connection.getAccount().address
+                                    + ": encountered unknown media in session proposal. "
+                                    + propose);
+                    return;
+                }
+                final Optional<RtpSessionProposal> matchingSessionProposal =
+                        findMatchingSessionProposal(id.with, ImmutableSet.copyOf(media));
+                if (matchingSessionProposal.isPresent()) {
+                    final String ourSessionId = matchingSessionProposal.get().sessionId;
+                    final String theirSessionId = id.sessionId;
+                    if (ComparisonChain.start()
+                                    .compare(ourSessionId, theirSessionId)
+                                    .compare(
+                                            connection.getBoundAddress().toString(),
+                                            id.with.toString())
+                                    .result()
+                            > 0) {
+                        LOGGER.debug(
+                                connection.getAccount().address
+                                        + ": our session lost tie break. automatically accepting"
+                                        + " their session. winning Session="
+                                        + theirSessionId);
+                        // TODO a retract for this reason should probably include some indication of
+                        // tie break
+                        retractSessionProposal(matchingSessionProposal.get());
+                        final JingleRtpConnection rtpConnection =
+                                new JingleRtpConnection(context, this.connection, id, from);
+                        this.connections.put(id, rtpConnection);
+                        rtpConnection.setProposedMedia(ImmutableSet.copyOf(media));
+                        rtpConnection.deliveryMessage(from, message, serverMsgId);
+                    } else {
+                        LOGGER.debug(
+                                connection.getAccount().address
+                                        + ": our session won tie break. waiting for other party to"
+                                        + " accept. winningSession="
+                                        + ourSessionId);
+                    }
+                    return;
+                }
+                final boolean stranger = isWithStrangerAndStrangerNotificationsAreOff(id.with);
+                if (isBusy() || stranger) {
+                    writeLogMissedIncoming(id.with.asBareJid(), id.sessionId, serverMsgId);
+                    if (stranger) {
+                        LOGGER.debug(
+                                connection.getAccount().address
+                                        + ": ignoring call proposal from stranger "
+                                        + id.with);
+                        return;
+                    }
+                    final int activeDevices =
+                            getDatabase()
+                                    .discoDao()
+                                    .countPresencesWithFeature(
+                                            getAccount(), Namespace.JINGLE_APPS_RTP);
+                    Log.d(Config.LOGTAG, "active devices with rtp capability: " + activeDevices);
+                    if (activeDevices == 0) {
+                        final Message reject = MessageGenerator.sessionReject(from, sessionId);
+                        connection.sendMessagePacket(reject);
+                    } else {
+                        LOGGER.debug(
+                                connection.getAccount().address
+                                        + ": ignoring proposal because busy on this device but"
+                                        + " there are other devices");
+                    }
+                } else {
+                    final JingleRtpConnection rtpConnection =
+                            new JingleRtpConnection(context, this.connection, id, from);
+                    this.connections.put(id, rtpConnection);
+                    rtpConnection.setProposedMedia(ImmutableSet.copyOf(media));
+                    rtpConnection.deliveryMessage(from, message, serverMsgId);
+                }
+            } else {
+                LOGGER.debug(
+                        connection.getAccount().address
+                                + ": unable to react to proposed session with "
+                                + rtpDescriptions.size()
+                                + " rtp descriptions of "
+                                + descriptions.size()
+                                + " total descriptions");
+            }
+        } else if (addressedDirectly && "proceed".equals(message.getName())) {
+            synchronized (rtpSessionProposals) {
+                final RtpSessionProposal proposal =
+                        getRtpSessionProposal(from.asBareJid(), sessionId);
+                if (proposal != null) {
+                    rtpSessionProposals.remove(proposal);
+                    final JingleRtpConnection rtpConnection =
+                            new JingleRtpConnection(
+                                    context,
+                                    this.connection,
+                                    id,
+                                    this.connection.getBoundAddress());
+                    rtpConnection.setProposedMedia(proposal.media);
+                    this.connections.put(id, rtpConnection);
+                    rtpConnection.transitionOrThrow(AbstractJingleConnection.State.PROPOSED);
+                    rtpConnection.deliveryMessage(from, message, serverMsgId);
+                } else {
+                    LOGGER.debug(
+                            connection.getAccount().address
+                                    + ": no rtp session proposal found for "
+                                    + from
+                                    + " to deliver proceed");
+                    if (remoteMsgId == null) {
+                        return;
+                    }
+                    final Message errorMessage = new Message();
+                    errorMessage.setTo(from);
+                    errorMessage.setId(remoteMsgId);
+                    errorMessage.setType(Message.Type.ERROR);
+                    final Element error = errorMessage.addChild("error");
+                    error.setAttribute("code", "404");
+                    error.setAttribute("type", "cancel");
+                    error.addChild("item-not-found", "urn:ietf:params:xml:ns:xmpp-stanzas");
+                    connection.sendMessagePacket(errorMessage);
+                }
+            }
+        } else if (addressedDirectly && "reject".equals(message.getName())) {
+            final RtpSessionProposal proposal = getRtpSessionProposal(from.asBareJid(), sessionId);
+            synchronized (rtpSessionProposals) {
+                if (proposal != null && rtpSessionProposals.remove(proposal) != null) {
+                    writeLogMissedOutgoing(proposal.with, proposal.sessionId, serverMsgId);
+                    ToneManager.getInstance(context)
+                            .transition(RtpEndUserState.DECLINED_OR_BUSY, proposal.media);
+                    notifyJingleRtpConnectionUpdate(
+                            proposal.with, proposal.sessionId, RtpEndUserState.DECLINED_OR_BUSY);
+                } else {
+                    LOGGER.debug(
+                            connection.getAccount().address
+                                    + ": no rtp session proposal found for "
+                                    + from
+                                    + " to deliver reject");
+                }
+            }
+        } else {
+            LOGGER.debug(
+                    connection.getAccount().address
+                            + ": retrieved out of order jingle message"
+                            + message);
+        }
+    }
+
+    private RtpSessionProposal getRtpSessionProposal(Jid from, String sessionId) {
+        for (RtpSessionProposal rtpSessionProposal : rtpSessionProposals.keySet()) {
+            if (rtpSessionProposal.sessionId.equals(sessionId)
+                    && rtpSessionProposal.with.equals(from)) {
+                return rtpSessionProposal;
+            }
+        }
+        return null;
+    }
+
+    private void writeLogMissedOutgoing(Jid with, final String sessionId, String serverMsgId) {}
+
+    private void writeLogMissedIncoming(Jid with, final String sessionId, String serverMsgId) {}
+
+    public Optional<OngoingRtpSession> getOngoingRtpConnection(final Jid contact) {
+        for (final Map.Entry<AbstractJingleConnection.Id, AbstractJingleConnection> entry :
+                this.connections.entrySet()) {
+            if (entry.getValue() instanceof JingleRtpConnection) {
+                final AbstractJingleConnection.Id id = entry.getKey();
+                if (id.with.asBareJid().equals(contact.asBareJid())) {
+                    return Optional.of(id);
+                }
+            }
+        }
+        synchronized (this.rtpSessionProposals) {
+            for (final Map.Entry<RtpSessionProposal, DeviceDiscoveryState> entry :
+                    this.rtpSessionProposals.entrySet()) {
+                final RtpSessionProposal proposal = entry.getKey();
+                if (contact.asBareJid().equals(proposal.with)) {
+                    final DeviceDiscoveryState preexistingState = entry.getValue();
+                    if (preexistingState != null
+                            && preexistingState != DeviceDiscoveryState.FAILED) {
+                        return Optional.of(proposal);
+                    }
+                }
+            }
+        }
+        return Optional.absent();
+    }
+
+    void finishConnection(final AbstractJingleConnection connection) {
+        this.connections.remove(connection.getId());
+    }
+
+    public void finishConnectionOrThrow(final AbstractJingleConnection connection) {
+        final AbstractJingleConnection.Id id = connection.getId();
+        if (this.connections.remove(id) == null) {
+            throw new IllegalStateException(
+                    String.format("Unable to finish connection with id=%s", id.toString()));
+        }
+    }
+
+    public boolean fireJingleRtpConnectionStateUpdates() {
+        boolean firedUpdates = false;
+        for (final AbstractJingleConnection connection : this.connections.values()) {
+            if (connection instanceof JingleRtpConnection) {
+                final JingleRtpConnection jingleRtpConnection = (JingleRtpConnection) connection;
+                if (jingleRtpConnection.isTerminated()) {
+                    continue;
+                }
+                jingleRtpConnection.fireStateUpdate();
+                firedUpdates = true;
+            }
+        }
+        return firedUpdates;
+    }
+
+    public void retractSessionProposal(final Jid with) {
+        synchronized (this.rtpSessionProposals) {
+            RtpSessionProposal matchingProposal = null;
+            for (RtpSessionProposal proposal : this.rtpSessionProposals.keySet()) {
+                if (with.asBareJid().equals(proposal.with)) {
+                    matchingProposal = proposal;
+                    break;
+                }
+            }
+            if (matchingProposal != null) {
+                retractSessionProposal(matchingProposal);
+            }
+        }
+    }
+
+    private void retractSessionProposal(RtpSessionProposal rtpSessionProposal) {
+        ToneManager.getInstance(context)
+                .transition(RtpEndUserState.ENDED, rtpSessionProposal.media);
+        LOGGER.debug(
+                connection.getAccount().address
+                        + ": retracting rtp session proposal with "
+                        + rtpSessionProposal.with);
+        this.rtpSessionProposals.remove(rtpSessionProposal);
+        final Message messagePacket = MessageGenerator.sessionRetract(rtpSessionProposal);
+        writeLogMissedOutgoing(rtpSessionProposal.with, rtpSessionProposal.sessionId, null);
+        connection.sendMessagePacket(messagePacket);
+    }
+
+    public String initializeRtpSession(final Jid with, final Set<Media> media) {
+        final AbstractJingleConnection.Id id = AbstractJingleConnection.Id.of(with);
+        final JingleRtpConnection rtpConnection =
+                new JingleRtpConnection(
+                        context, this.connection, id, this.connection.getBoundAddress());
+        rtpConnection.setProposedMedia(media);
+        this.connections.put(id, rtpConnection);
+        rtpConnection.sendSessionInitiate();
+        return id.sessionId;
+    }
+
+    public void proposeJingleRtpSession(final Jid with, final Set<Media> media) {
+        synchronized (this.rtpSessionProposals) {
+            for (Map.Entry<RtpSessionProposal, DeviceDiscoveryState> entry :
+                    this.rtpSessionProposals.entrySet()) {
+                RtpSessionProposal proposal = entry.getKey();
+                if (with.asBareJid().equals(proposal.with)) {
+                    final DeviceDiscoveryState preexistingState = entry.getValue();
+                    if (preexistingState != null
+                            && preexistingState != DeviceDiscoveryState.FAILED) {
+                        final RtpEndUserState endUserState = preexistingState.toEndUserState();
+                        ToneManager.getInstance(context).transition(endUserState, media);
+                        this.notifyJingleRtpConnectionUpdate(
+                                with, proposal.sessionId, endUserState);
+                        return;
+                    }
+                }
+            }
+            if (isBusy()) {
+                if (hasMatchingRtpSession(with, media)) {
+                    LOGGER.debug(
+                            "ignoring request to propose jingle session because the other party"
+                                    + " already created one for us");
+                    return;
+                }
+                throw new IllegalStateException(
+                        "There is already a running RTP session. This should have been caught by"
+                                + " the UI");
+            }
+            final RtpSessionProposal proposal = RtpSessionProposal.of(with.asBareJid(), media);
+            this.rtpSessionProposals.put(proposal, DeviceDiscoveryState.SEARCHING);
+            this.notifyJingleRtpConnectionUpdate(
+                    proposal.with, proposal.sessionId, RtpEndUserState.FINDING_DEVICE);
+            final Message messagePacket = MessageGenerator.sessionProposal(proposal);
+            connection.sendMessagePacket(messagePacket);
+        }
+    }
+
+    public boolean hasMatchingProposal(final Jid with) {
+        synchronized (this.rtpSessionProposals) {
+            for (Map.Entry<RtpSessionProposal, DeviceDiscoveryState> entry :
+                    this.rtpSessionProposals.entrySet()) {
+                final RtpSessionProposal proposal = entry.getKey();
+                if (with.asBareJid().equals(proposal.with)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    public void notifyRebound() {
+        for (final AbstractJingleConnection connection : this.connections.values()) {
+            connection.notifyRebound();
+        }
+        // TODO the old version did this only when SM was enabled?!
+        resendSessionProposals();
+    }
+
+    public WeakReference<JingleRtpConnection> findJingleRtpConnection(Jid with, String sessionId) {
+        final AbstractJingleConnection.Id id = AbstractJingleConnection.Id.of(with, sessionId);
+        final AbstractJingleConnection connection = connections.get(id);
+        if (connection instanceof JingleRtpConnection) {
+            return new WeakReference<>((JingleRtpConnection) connection);
+        }
+        return null;
+    }
+
+    private void resendSessionProposals() {
+        synchronized (this.rtpSessionProposals) {
+            for (final Map.Entry<RtpSessionProposal, DeviceDiscoveryState> entry :
+                    this.rtpSessionProposals.entrySet()) {
+                final RtpSessionProposal proposal = entry.getKey();
+                if (entry.getValue() == DeviceDiscoveryState.SEARCHING) {
+                    LOGGER.debug(
+                            connection.getAccount().address
+                                    + ": resending session proposal to "
+                                    + proposal.with);
+                    final Message messagePacket = MessageGenerator.sessionProposal(proposal);
+                    connection.sendMessagePacket(messagePacket);
+                }
+            }
+        }
+    }
+
+    public void updateProposedSessionDiscovered(
+            Jid from, String sessionId, final DeviceDiscoveryState target) {
+        synchronized (this.rtpSessionProposals) {
+            final RtpSessionProposal sessionProposal =
+                    getRtpSessionProposal(from.asBareJid(), sessionId);
+            final DeviceDiscoveryState currentState =
+                    sessionProposal == null ? null : rtpSessionProposals.get(sessionProposal);
+            if (currentState == null) {
+                Log.d(Config.LOGTAG, "unable to find session proposal for session id " + sessionId);
+                return;
+            }
+            if (currentState == DeviceDiscoveryState.DISCOVERED) {
+                LOGGER.debug("session proposal already at discovered. not going to fall back");
+                return;
+            }
+            this.rtpSessionProposals.put(sessionProposal, target);
+            final RtpEndUserState endUserState = target.toEndUserState();
+            ToneManager.getInstance(context).transition(endUserState, sessionProposal.media);
+            this.notifyJingleRtpConnectionUpdate(
+                    sessionProposal.with, sessionProposal.sessionId, endUserState);
+            LOGGER.debug(
+                    connection.getAccount().address
+                            + ": flagging session "
+                            + sessionId
+                            + " as "
+                            + target);
+        }
+    }
+
+    public void rejectRtpSession(final String sessionId) {
+        for (final AbstractJingleConnection connection : this.connections.values()) {
+            if (connection.getId().sessionId.equals(sessionId)) {
+                if (connection instanceof JingleRtpConnection) {
+                    try {
+                        ((JingleRtpConnection) connection).rejectCall();
+                        return;
+                    } catch (final IllegalStateException e) {
+                        Log.w(
+                                Config.LOGTAG,
+                                "race condition on rejecting call from notification",
+                                e);
+                    }
+                }
+            }
+        }
+    }
+
+    public void endRtpSession(final String sessionId) {
+        for (final AbstractJingleConnection connection : this.connections.values()) {
+            if (connection.getId().sessionId.equals(sessionId)) {
+                if (connection instanceof JingleRtpConnection) {
+                    ((JingleRtpConnection) connection).endCall();
+                }
+            }
+        }
+    }
+
+    public void failProceed(final Jid with, final String sessionId, final String message) {
+        final AbstractJingleConnection.Id id = AbstractJingleConnection.Id.of(with, sessionId);
+        final AbstractJingleConnection existingJingleConnection = connections.get(id);
+        if (existingJingleConnection instanceof JingleRtpConnection) {
+            ((JingleRtpConnection) existingJingleConnection).deliverFailedProceed(message);
+        }
+    }
+
+    public void ensureConnectionIsRegistered(final AbstractJingleConnection connection) {
+        if (connections.containsValue(connection)) {
+            return;
+        }
+        final IllegalStateException e =
+                new IllegalStateException(
+                        "JingleConnection has not been registered with connection manager");
+        Log.e(Config.LOGTAG, "ensureConnectionIsRegistered() failed. Going to throw", e);
+        throw e;
+    }
+
+    public void setTerminalSessionState(
+            AbstractJingleConnection.Id id, final RtpEndUserState state, final Set<Media> media) {
+        this.terminatedSessions.put(
+                PersistableSessionId.of(id), new TerminatedRtpSession(state, media));
+    }
+
+    public TerminatedRtpSession getTerminalSessionState(final Jid with, final String sessionId) {
+        return this.terminatedSessions.getIfPresent(new PersistableSessionId(with, sessionId));
+    }
+
+    public void notifyJingleRtpConnectionUpdate(
+            final Jid with, final String sessionId, final RtpEndUserState state) {
+        final var listener = this.onJingleRtpConnectionUpdate;
+        if (listener == null) {
+            return;
+        }
+        listener.onJingleRtpConnectionUpdate(with, sessionId, state);
+    }
+
+    public void notifyJingleRtpConnectionUpdate(
+            AppRTCAudioManager.AudioDevice selectedAudioDevice,
+            Set<AppRTCAudioManager.AudioDevice> availableAudioDevices) {
+        final var listener = this.onJingleRtpConnectionUpdate;
+        if (listener == null) {
+            return;
+        }
+        listener.onAudioDeviceChanged(selectedAudioDevice, availableAudioDevices);
+    }
+
+    public void setOnJingleRtpConnectionUpdate(final OnJingleRtpConnectionUpdate listener) {
+        this.onJingleRtpConnectionUpdate = listener;
+    }
+
+    public RtpSessionNotification getNotificationService() {
+        return this.rtpSessionNotification;
+    }
+
+    public interface OnJingleRtpConnectionUpdate {
+        void onJingleRtpConnectionUpdate(
+                final Jid with, final String sessionId, final RtpEndUserState state);
+
+        void onAudioDeviceChanged(
+                AppRTCAudioManager.AudioDevice selectedAudioDevice,
+                Set<AppRTCAudioManager.AudioDevice> availableAudioDevices);
+    }
+
+    private static class PersistableSessionId {
+        private final Jid with;
+        private final String sessionId;
+
+        private PersistableSessionId(Jid with, String sessionId) {
+            this.with = with;
+            this.sessionId = sessionId;
+        }
+
+        public static PersistableSessionId of(AbstractJingleConnection.Id id) {
+            return new PersistableSessionId(id.with, id.sessionId);
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            PersistableSessionId that = (PersistableSessionId) o;
+            return Objects.equal(with, that.with) && Objects.equal(sessionId, that.sessionId);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(with, sessionId);
+        }
+    }
+
+    public static class TerminatedRtpSession {
+        public final RtpEndUserState state;
+        public final Set<Media> media;
+
+        TerminatedRtpSession(RtpEndUserState state, Set<Media> media) {
+            this.state = state;
+            this.media = media;
+        }
+    }
+
+    public enum DeviceDiscoveryState {
+        SEARCHING,
+        SEARCHING_ACKNOWLEDGED,
+        DISCOVERED,
+        FAILED;
+
+        public RtpEndUserState toEndUserState() {
+            switch (this) {
+                case SEARCHING:
+                case SEARCHING_ACKNOWLEDGED:
+                    return RtpEndUserState.FINDING_DEVICE;
+                case DISCOVERED:
+                    return RtpEndUserState.RINGING;
+                default:
+                    return RtpEndUserState.CONNECTIVITY_ERROR;
+            }
+        }
+    }
+
+    public static class RtpSessionProposal implements OngoingRtpSession {
+        public final Jid with;
+        public final String sessionId;
+        public final Set<Media> media;
+
+        private RtpSessionProposal(Jid with, String sessionId) {
+            this(with, sessionId, Collections.emptySet());
+        }
+
+        private RtpSessionProposal(Jid with, String sessionId, Set<Media> media) {
+            this.with = with;
+            this.sessionId = sessionId;
+            this.media = media;
+        }
+
+        public static RtpSessionProposal of(Jid with, Set<Media> media) {
+            return new RtpSessionProposal(with, IDs.medium(), media);
+        }
+
+        @Override
+        public Jid getWith() {
+            return with;
+        }
+
+        @Override
+        public String getSessionId() {
+            return sessionId;
+        }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            RtpSessionProposal that = (RtpSessionProposal) o;
+            return Objects.equal(with, that.with)
+                    && Objects.equal(sessionId, that.sessionId)
+                    && Objects.equal(media, that.media);
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hashCode(with, sessionId, media);
+        }
     }
 }

app/src/main/java/im/conversations/android/xmpp/manager/StanzaIdManager.java

@@ -2,6 +2,7 @@ package im.conversations.android.xmpp.manager;
 
 import android.content.Context;
 import im.conversations.android.xml.Namespace;
+import im.conversations.android.xmpp.Entity;
 import im.conversations.android.xmpp.XmppConnection;
 import im.conversations.android.xmpp.model.stanza.Message;
 import im.conversations.android.xmpp.model.unique.StanzaId;
@@ -25,7 +26,8 @@ public class StanzaIdManager extends AbstractManager {
             by = connection.getBoundAddress().asBareJid();
         }
         if (message.hasExtension(StanzaId.class)
-                && getManager(DiscoManager.class).hasFeature(by, Namespace.STANZA_IDS)) {
+                && getManager(DiscoManager.class)
+                        .hasFeature(Entity.discoItem(by), Namespace.STANZA_IDS)) {
             return getStanzaIdBy(message, by);
         } else {
             return null;

app/src/main/java/im/conversations/android/xmpp/model/axolotl/Encrypted.java

@@ -13,4 +13,12 @@ public class Encrypted extends Extension {
     public boolean hasPayload() {
         return hasExtension(Payload.class);
     }
+
+    public Header getHeader() {
+        return getExtension(Header.class);
+    }
+
+    public Payload getPayload() {
+        return getExtension(Payload.class);
+    }
 }

app/src/main/java/im/conversations/android/xmpp/model/axolotl/Header.java

@@ -1,7 +1,11 @@
 package im.conversations.android.xmpp.model.axolotl;
 
+import com.google.common.base.Optional;
+import com.google.common.collect.Iterables;
 import im.conversations.android.annotation.XmlElement;
 import im.conversations.android.xmpp.model.Extension;
+import java.util.Collection;
+import java.util.Objects;
 
 @XmlElement
 public class Header extends Extension {
@@ -9,4 +13,33 @@ public class Header extends Extension {
     public Header() {
         super(Header.class);
     }
+
+    public void addIv(byte[] iv) {
+        this.addExtension(new IV()).setContent(iv);
+    }
+
+    public void setSourceDevice(long sourceDeviceId) {
+        this.setAttribute("sid", sourceDeviceId);
+    }
+
+    public Optional<Integer> getSourceDevice() {
+        return getOptionalIntAttribute("sid");
+    }
+
+    public Collection<Key> getKeys() {
+        return this.getExtensions(Key.class);
+    }
+
+    public Key getKey(final int deviceId) {
+        return Iterables.find(
+                getKeys(), key -> Objects.equals(key.getRemoteDeviceId(), deviceId), null);
+    }
+
+    public byte[] getIv() {
+        final IV iv = this.getExtension(IV.class);
+        if (iv == null) {
+            throw new IllegalStateException("No IV in header");
+        }
+        return iv.asBytes();
+    }
 }

app/src/main/java/im/conversations/android/xmpp/model/axolotl/IV.java

@@ -0,0 +1,13 @@
+package im.conversations.android.xmpp.model.axolotl;
+
+import im.conversations.android.annotation.XmlElement;
+import im.conversations.android.xmpp.model.ByteContent;
+import im.conversations.android.xmpp.model.Extension;
+
+@XmlElement
+public class IV extends Extension implements ByteContent {
+
+    public IV() {
+        super(IV.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/axolotl/Key.java

@@ -0,0 +1,29 @@
+package im.conversations.android.xmpp.model.axolotl;
+
+import im.conversations.android.annotation.XmlElement;
+import im.conversations.android.xmpp.model.ByteContent;
+import im.conversations.android.xmpp.model.Extension;
+
+@XmlElement
+public class Key extends Extension implements ByteContent {
+
+    public Key() {
+        super(Key.class);
+    }
+
+    public void setIsPreKey(boolean isPreKey) {
+        this.setAttribute("prekey", isPreKey);
+    }
+
+    public boolean isPreKey() {
+        return this.getAttributeAsBoolean("prekey");
+    }
+
+    public void setRemoteDeviceId(final int remoteDeviceId) {
+        this.setAttribute("rid", remoteDeviceId);
+    }
+
+    public Integer getRemoteDeviceId() {
+        return getOptionalIntAttribute("rid").orNull();
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/axolotl/Payload.java

@@ -1,10 +1,11 @@
 package im.conversations.android.xmpp.model.axolotl;
 
 import im.conversations.android.annotation.XmlElement;
+import im.conversations.android.xmpp.model.ByteContent;
 import im.conversations.android.xmpp.model.Extension;
 
 @XmlElement
-public class Payload extends Extension {
+public class Payload extends Extension implements ByteContent {
 
     public Payload() {
         super(Payload.class);

app/src/main/java/im/conversations/android/xmpp/model/disco/external/Service.java

@@ -0,0 +1,12 @@
+package im.conversations.android.xmpp.model.disco.external;
+
+import im.conversations.android.annotation.XmlElement;
+import im.conversations.android.xmpp.model.Extension;
+
+@XmlElement
+public class Service extends Extension {
+
+    public Service() {
+        super(Service.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/disco/external/Services.java

@@ -0,0 +1,12 @@
+package im.conversations.android.xmpp.model.disco.external;
+
+import im.conversations.android.annotation.XmlElement;
+import im.conversations.android.xmpp.model.Extension;
+
+@XmlElement
+public class Services extends Extension {
+
+    public Services() {
+        super(Services.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/disco/external/package-info.java

@@ -0,0 +1,5 @@
+@XmlPackage(namespace = Namespace.EXTERNAL_SERVICE_DISCOVERY)
+package im.conversations.android.xmpp.model.disco.external;
+
+import im.conversations.android.annotation.XmlPackage;
+import im.conversations.android.xml.Namespace;

app/src/main/java/im/conversations/android/xmpp/model/jingle/Jingle.java

@@ -6,7 +6,6 @@ import im.conversations.android.xmpp.model.Extension;
 @XmlElement
 public class Jingle extends Extension {
 
-
     public Jingle() {
         super(Jingle.class);
     }

app/src/main/java/im/conversations/android/xmpp/model/jingle/package-info.java

@@ -0,0 +1,5 @@
+@XmlPackage(namespace = Namespace.JINGLE)
+package im.conversations.android.xmpp.model.jingle;
+
+import im.conversations.android.annotation.XmlPackage;
+import im.conversations.android.xml.Namespace;

app/src/main/java/im/conversations/android/xmpp/model/jmi/Accept.java

@@ -0,0 +1,8 @@
+package im.conversations.android.xmpp.model.jmi;
+
+public class Accept extends JingleMessage {
+
+    public Accept() {
+        super(Accept.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/JingleMessage.java

@@ -0,0 +1,14 @@
+package im.conversations.android.xmpp.model.jmi;
+
+import im.conversations.android.xmpp.model.Extension;
+
+public abstract class JingleMessage extends Extension {
+
+    public JingleMessage(Class<? extends Extension> clazz) {
+        super(clazz);
+    }
+
+    public String getSessionId() {
+        return this.getAttribute("id");
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/Proceed.java

@@ -0,0 +1,20 @@
+package im.conversations.android.xmpp.model.jmi;
+
+import com.google.common.primitives.Ints;
+import im.conversations.android.xml.Element;
+
+public class Proceed extends JingleMessage {
+
+    public Proceed() {
+        super(Propose.class);
+    }
+
+    public Integer getDeviceId() {
+        final Element device = this.findChild("device");
+        final String id = device == null ? null : device.getAttribute("id");
+        if (id == null) {
+            return null;
+        }
+        return Ints.tryParse(id);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/Propose.java

@@ -0,0 +1,33 @@
+package im.conversations.android.xmpp.model.jmi;
+
+import com.google.common.collect.ImmutableList;
+import eu.siacs.conversations.xmpp.jingle.stanzas.FileTransferDescription;
+import eu.siacs.conversations.xmpp.jingle.stanzas.GenericDescription;
+import eu.siacs.conversations.xmpp.jingle.stanzas.RtpDescription;
+import im.conversations.android.xml.Element;
+import im.conversations.android.xml.Namespace;
+import java.util.List;
+
+public class Propose extends JingleMessage {
+
+    public Propose() {
+        super(Propose.class);
+    }
+
+    public List<GenericDescription> getDescriptions() {
+        final ImmutableList.Builder<GenericDescription> builder = new ImmutableList.Builder<>();
+        for (final Element child : this.children) {
+            if ("description".equals(child.getName())) {
+                final String namespace = child.getNamespace();
+                if (FileTransferDescription.NAMESPACES.contains(namespace)) {
+                    builder.add(FileTransferDescription.upgrade(child));
+                } else if (Namespace.JINGLE_APPS_RTP.equals(namespace)) {
+                    builder.add(RtpDescription.upgrade(child));
+                } else {
+                    builder.add(GenericDescription.upgrade(child));
+                }
+            }
+        }
+        return builder.build();
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/Reject.java

@@ -0,0 +1,8 @@
+package im.conversations.android.xmpp.model.jmi;
+
+public class Reject extends JingleMessage {
+
+    public Reject() {
+        super(Reject.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/Retract.java

@@ -0,0 +1,8 @@
+package im.conversations.android.xmpp.model.jmi;
+
+public class Retract extends JingleMessage {
+
+    public Retract() {
+        super(Retract.class);
+    }
+}

app/src/main/java/im/conversations/android/xmpp/model/jmi/package-info.java

@@ -0,0 +1,5 @@
+@XmlPackage(namespace = Namespace.JINGLE_MESSAGE)
+package im.conversations.android.xmpp.model.jmi;
+
+import im.conversations.android.annotation.XmlPackage;
+import im.conversations.android.xml.Namespace;

app/src/main/java/im/conversations/android/xmpp/processor/IqProcessor.java

@@ -73,6 +73,7 @@ public class IqProcessor extends XmppConnection.Delegate implements Consumer<Iq>
 
         if (type == Iq.Type.SET && packet.hasExtension(Jingle.class)) {
             getManager(JingleConnectionManager.class).handleJingle(packet);
+            return;
         }
 
         final var extensionIds = packet.getExtensionIds();

app/src/main/res/drawable/ic_bluetooth_audio_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#000000"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M14.24,12.01l2.32,2.32c0.28,-0.72 0.44,-1.51 0.44,-2.33 0,-0.82 -0.16,-1.59 -0.43,-2.31l-2.33,2.32zM19.53,6.71l-1.26,1.26c0.63,1.21 0.98,2.57 0.98,4.02s-0.36,2.82 -0.98,4.02l1.2,1.2c0.97,-1.54 1.54,-3.36 1.54,-5.31 -0.01,-1.89 -0.55,-3.67 -1.48,-5.19zM15.71,7.71L10,2L9,2v7.59L4.41,5 3,6.41 8.59,12 3,17.59 4.41,19 9,14.41L9,22h1l5.71,-5.71 -4.3,-4.29 4.3,-4.29zM11,5.83l1.88,1.88L11,9.59L11,5.83zM12.88,16.29L11,18.17v-3.76l1.88,1.88z"/>
+</vector>

app/src/main/res/drawable/ic_call_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#000000"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M20.01,15.38c-1.23,0 -2.42,-0.2 -3.53,-0.56 -0.35,-0.12 -0.74,-0.03 -1.01,0.24l-1.57,1.97c-2.83,-1.35 -5.48,-3.9 -6.89,-6.83l1.95,-1.66c0.27,-0.28 0.35,-0.67 0.24,-1.02 -0.37,-1.11 -0.56,-2.3 -0.56,-3.53 0,-0.54 -0.45,-0.99 -0.99,-0.99H4.19C3.65,3 3,3.24 3,3.99 3,13.28 10.73,21 20.01,21c0.71,0 0.99,-0.63 0.99,-1.18v-3.45c0,-0.54 -0.45,-0.99 -0.99,-0.99z"/>
+</vector>

app/src/main/res/drawable/ic_call_end_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#000000"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M12,9c-1.6,0 -3.15,0.25 -4.6,0.72v3.1c0,0.39 -0.23,0.74 -0.56,0.9 -0.98,0.49 -1.87,1.12 -2.66,1.85 -0.18,0.18 -0.43,0.28 -0.7,0.28 -0.28,0 -0.53,-0.11 -0.71,-0.29L0.29,13.08c-0.18,-0.17 -0.29,-0.42 -0.29,-0.7 0,-0.28 0.11,-0.53 0.29,-0.71C3.34,8.78 7.46,7 12,7s8.66,1.78 11.71,4.67c0.18,0.18 0.29,0.43 0.29,0.71 0,0.28 -0.11,0.53 -0.29,0.71l-2.48,2.48c-0.18,0.18 -0.43,0.29 -0.71,0.29 -0.27,0 -0.52,-0.11 -0.7,-0.28 -0.79,-0.74 -1.69,-1.36 -2.67,-1.85 -0.33,-0.16 -0.56,-0.5 -0.56,-0.9v-3.1C15.15,9.25 13.6,9 12,9z"/>
+</vector>

app/src/main/res/drawable/ic_chat_24dp.xml

@@ -1,11 +1,5 @@
-<vector xmlns:android="http://schemas.android.com/apk/res/android"
-    android:width="24dp"
-    android:height="24dp"
-    android:autoMirrored="true"
-    android:tint="?attr/colorControlNormal"
-    android:viewportWidth="24"
-    android:viewportHeight="24">
-    <path
-        android:fillColor="@android:color/white"
-        android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM6,9h12v2L6,11L6,9zM14,14L6,14v-2h8v2zM18,8L6,8L6,6h12v2z" />
+<vector android:autoMirrored="true" android:height="24dp"
+    android:tint="#000000" android:viewportHeight="24"
+    android:viewportWidth="24" android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M20,2L4,2c-1.1,0 -1.99,0.9 -1.99,2L2,22l4,-4h14c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM6,9h12v2L6,11L6,9zM14,14L6,14v-2h8v2zM18,8L6,8L6,6h12v2z"/>
 </vector>

app/src/main/res/drawable/ic_check_24dp.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#000000"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M9,16.17L4.83,12l-1.42,1.41L9,19 21,7l-1.41,-1.41z"/>
+</vector>