436 lines
17 KiB
Java
436 lines
17 KiB
Java
package eu.siacs.conversations.utils;
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import android.content.ContentValues;
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import android.database.Cursor;
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import android.util.Log;
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import androidx.annotation.NonNull;
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import java.io.IOException;
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import java.lang.reflect.Field;
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import java.net.Inet4Address;
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import java.net.InetAddress;
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import java.net.UnknownHostException;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.List;
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import de.measite.minidns.AbstractDNSClient;
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import de.measite.minidns.DNSCache;
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import de.measite.minidns.DNSClient;
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import de.measite.minidns.DNSName;
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import de.measite.minidns.Question;
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import de.measite.minidns.Record;
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import de.measite.minidns.cache.LRUCache;
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import de.measite.minidns.dnssec.DNSSECResultNotAuthenticException;
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import de.measite.minidns.dnsserverlookup.AndroidUsingExec;
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import de.measite.minidns.hla.DnssecResolverApi;
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import de.measite.minidns.hla.ResolverApi;
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import de.measite.minidns.hla.ResolverResult;
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import de.measite.minidns.iterative.ReliableDNSClient;
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import de.measite.minidns.record.A;
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import de.measite.minidns.record.AAAA;
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import de.measite.minidns.record.CNAME;
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import de.measite.minidns.record.Data;
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import de.measite.minidns.record.InternetAddressRR;
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import de.measite.minidns.record.SRV;
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import eu.siacs.conversations.Config;
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import eu.siacs.conversations.R;
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import eu.siacs.conversations.services.XmppConnectionService;
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public class Resolver {
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public static final int DEFAULT_PORT_XMPP = 5222;
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private static final String DIRECT_TLS_SERVICE = "_xmpps-client";
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private static final String STARTTLS_SERVICE = "_xmpp-client";
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private static XmppConnectionService SERVICE = null;
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public static void init(XmppConnectionService service) {
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Resolver.SERVICE = service;
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DNSClient.removeDNSServerLookupMechanism(AndroidUsingExec.INSTANCE);
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DNSClient.addDnsServerLookupMechanism(AndroidUsingExecLowPriority.INSTANCE);
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DNSClient.addDnsServerLookupMechanism(new AndroidUsingLinkProperties(service));
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final AbstractDNSClient client = ResolverApi.INSTANCE.getClient();
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if (client instanceof ReliableDNSClient) {
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disableHardcodedDnsServers((ReliableDNSClient) client);
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}
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}
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private static void disableHardcodedDnsServers(ReliableDNSClient reliableDNSClient) {
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try {
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final Field dnsClientField = ReliableDNSClient.class.getDeclaredField("dnsClient");
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dnsClientField.setAccessible(true);
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final DNSClient dnsClient = (DNSClient) dnsClientField.get(reliableDNSClient);
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if (dnsClient != null) {
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dnsClient.getDataSource().setTimeout(3000);
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}
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final Field useHardcodedDnsServers = DNSClient.class.getDeclaredField("useHardcodedDnsServers");
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useHardcodedDnsServers.setAccessible(true);
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useHardcodedDnsServers.setBoolean(dnsClient, false);
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} catch (NoSuchFieldException | IllegalAccessException e) {
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Log.e(Config.LOGTAG, "Unable to disable hardcoded DNS servers", e);
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}
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}
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public static List<Result> fromHardCoded(final String hostname, final int port) {
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final Result result = new Result();
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result.hostname = DNSName.from(hostname);
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result.port = port;
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result.directTls = useDirectTls(port);
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result.authenticated = true;
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return Collections.singletonList(result);
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}
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public static boolean invalidHostname(final String hostname) {
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try {
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DNSName.from(hostname);
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return false;
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} catch (IllegalArgumentException e) {
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return true;
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}
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}
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public static void clearCache() {
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final AbstractDNSClient client = ResolverApi.INSTANCE.getClient();
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final DNSCache dnsCache = client.getCache();
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if (dnsCache instanceof LRUCache) {
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Log.d(Config.LOGTAG,"clearing DNS cache");
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((LRUCache) dnsCache).clear();
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}
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}
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public static boolean useDirectTls(final int port) {
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return port == 443 || port == 5223;
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}
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public static List<Result> resolve(String domain) {
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final List<Result> ipResults = fromIpAddress(domain);
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if (ipResults.size() > 0) {
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return ipResults;
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}
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final List<Result> results = new ArrayList<>();
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final List<Result> fallbackResults = new ArrayList<>();
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final Thread[] threads = new Thread[3];
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threads[0] = new Thread(() -> {
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try {
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final List<Result> list = resolveSrv(domain, true);
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synchronized (results) {
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results.addAll(list);
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}
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} catch (Throwable throwable) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving SRV record (direct TLS)", throwable);
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}
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});
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threads[1] = new Thread(() -> {
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try {
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final List<Result> list = resolveSrv(domain, false);
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synchronized (results) {
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results.addAll(list);
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}
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} catch (Throwable throwable) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving SRV record (STARTTLS)", throwable);
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}
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});
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threads[2] = new Thread(() -> {
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List<Result> list = resolveNoSrvRecords(DNSName.from(domain), true);
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synchronized (fallbackResults) {
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fallbackResults.addAll(list);
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}
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});
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for (final Thread thread : threads) {
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thread.start();
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}
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try {
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threads[0].join();
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threads[1].join();
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if (results.size() > 0) {
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threads[2].interrupt();
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synchronized (results) {
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Collections.sort(results);
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": " + results.toString());
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return new ArrayList<>(results);
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}
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} else {
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threads[2].join();
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synchronized (fallbackResults) {
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Collections.sort(fallbackResults);
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": " + fallbackResults.toString());
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return new ArrayList<>(fallbackResults);
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}
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}
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} catch (InterruptedException e) {
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for (Thread thread : threads) {
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thread.interrupt();
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}
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return Collections.emptyList();
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}
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}
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private static List<Result> fromIpAddress(String domain) {
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if (!IP.matches(domain)) {
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return Collections.emptyList();
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}
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try {
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Result result = new Result();
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result.ip = InetAddress.getByName(domain);
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result.port = DEFAULT_PORT_XMPP;
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return Collections.singletonList(result);
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} catch (UnknownHostException e) {
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return Collections.emptyList();
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}
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}
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private static List<Result> resolveSrv(String domain, final boolean directTls) throws IOException {
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DNSName dnsName = DNSName.from((directTls ? DIRECT_TLS_SERVICE : STARTTLS_SERVICE) + "._tcp." + domain);
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ResolverResult<SRV> result = resolveWithFallback(dnsName, SRV.class);
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final List<Result> results = new ArrayList<>();
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final List<Thread> threads = new ArrayList<>();
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for (SRV record : result.getAnswersOrEmptySet()) {
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if (record.name.length() == 0 && record.priority == 0) {
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continue;
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}
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threads.add(new Thread(() -> {
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final List<Result> ipv4s = resolveIp(record, A.class, result.isAuthenticData(), directTls);
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if (ipv4s.size() == 0) {
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Result resolverResult = Result.fromRecord(record, directTls);
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resolverResult.authenticated = result.isAuthenticData();
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ipv4s.add(resolverResult);
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}
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synchronized (results) {
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results.addAll(ipv4s);
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}
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}));
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threads.add(new Thread(() -> {
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final List<Result> ipv6s = resolveIp(record, AAAA.class, result.isAuthenticData(), directTls);
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synchronized (results) {
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results.addAll(ipv6s);
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}
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}));
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}
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for (Thread thread : threads) {
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thread.start();
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}
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for (Thread thread : threads) {
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try {
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thread.join();
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} catch (InterruptedException e) {
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return Collections.emptyList();
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}
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}
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return results;
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}
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private static <D extends InternetAddressRR> List<Result> resolveIp(SRV srv, Class<D> type, boolean authenticated, boolean directTls) {
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List<Result> list = new ArrayList<>();
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try {
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ResolverResult<D> results = resolveWithFallback(srv.name, type, authenticated);
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for (D record : results.getAnswersOrEmptySet()) {
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Result resolverResult = Result.fromRecord(srv, directTls);
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resolverResult.authenticated = results.isAuthenticData() && authenticated; //TODO technically it doesn’t matter if the IP was authenticated
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resolverResult.ip = record.getInetAddress();
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list.add(resolverResult);
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}
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} catch (Throwable t) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving " + type.getSimpleName() + " " + t.getMessage());
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}
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return list;
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}
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private static List<Result> resolveNoSrvRecords(DNSName dnsName, boolean withCnames) {
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List<Result> results = new ArrayList<>();
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try {
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for (A a : resolveWithFallback(dnsName, A.class, false).getAnswersOrEmptySet()) {
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results.add(Result.createDefault(dnsName, a.getInetAddress()));
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}
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for (AAAA aaaa : resolveWithFallback(dnsName, AAAA.class, false).getAnswersOrEmptySet()) {
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results.add(Result.createDefault(dnsName, aaaa.getInetAddress()));
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}
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if (results.size() == 0 && withCnames) {
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for (CNAME cname : resolveWithFallback(dnsName, CNAME.class, false).getAnswersOrEmptySet()) {
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results.addAll(resolveNoSrvRecords(cname.name, false));
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}
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}
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} catch (Throwable throwable) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + "error resolving fallback records", throwable);
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}
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results.add(Result.createDefault(dnsName));
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return results;
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}
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private static <D extends Data> ResolverResult<D> resolveWithFallback(DNSName dnsName, Class<D> type) throws IOException {
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return resolveWithFallback(dnsName, type, validateHostname());
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}
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private static <D extends Data> ResolverResult<D> resolveWithFallback(DNSName dnsName, Class<D> type, boolean validateHostname) throws IOException {
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final Question question = new Question(dnsName, Record.TYPE.getType(type));
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if (!validateHostname) {
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return ResolverApi.INSTANCE.resolve(question);
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}
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try {
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return DnssecResolverApi.INSTANCE.resolveDnssecReliable(question);
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} catch (DNSSECResultNotAuthenticException e) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving " + type.getSimpleName() + " with DNSSEC. Trying DNS instead.", e);
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} catch (IOException e) {
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throw e;
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} catch (Throwable throwable) {
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Log.d(Config.LOGTAG, Resolver.class.getSimpleName() + ": error resolving " + type.getSimpleName() + " with DNSSEC. Trying DNS instead.", throwable);
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}
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return ResolverApi.INSTANCE.resolve(question);
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}
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private static boolean validateHostname() {
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return SERVICE != null && SERVICE.getBooleanPreference("validate_hostname", R.bool.validate_hostname);
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}
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public static class Result implements Comparable<Result> {
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public static final String DOMAIN = "domain";
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public static final String IP = "ip";
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public static final String HOSTNAME = "hostname";
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public static final String PORT = "port";
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public static final String PRIORITY = "priority";
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public static final String DIRECT_TLS = "directTls";
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public static final String AUTHENTICATED = "authenticated";
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private InetAddress ip;
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private DNSName hostname;
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private int port = DEFAULT_PORT_XMPP;
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private boolean directTls = false;
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private boolean authenticated = false;
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private int priority;
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static Result fromRecord(SRV srv, boolean directTls) {
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Result result = new Result();
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result.port = srv.port;
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result.hostname = srv.name;
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result.directTls = directTls;
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result.priority = srv.priority;
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return result;
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}
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static Result createDefault(DNSName hostname, InetAddress ip) {
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Result result = new Result();
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result.port = DEFAULT_PORT_XMPP;
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result.hostname = hostname;
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result.ip = ip;
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return result;
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}
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static Result createDefault(DNSName hostname) {
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return createDefault(hostname, null);
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}
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public static Result fromCursor(Cursor cursor) {
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final Result result = new Result();
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try {
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result.ip = InetAddress.getByAddress(cursor.getBlob(cursor.getColumnIndex(IP)));
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} catch (UnknownHostException e) {
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result.ip = null;
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}
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final String hostname = cursor.getString(cursor.getColumnIndex(HOSTNAME));
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result.hostname = hostname == null ? null : DNSName.from(hostname);
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result.port = cursor.getInt(cursor.getColumnIndex(PORT));
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result.priority = cursor.getInt(cursor.getColumnIndex(PRIORITY));
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result.authenticated = cursor.getInt(cursor.getColumnIndex(AUTHENTICATED)) > 0;
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result.directTls = cursor.getInt(cursor.getColumnIndex(DIRECT_TLS)) > 0;
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return result;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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Result result = (Result) o;
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if (port != result.port) return false;
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if (directTls != result.directTls) return false;
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if (authenticated != result.authenticated) return false;
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if (priority != result.priority) return false;
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if (ip != null ? !ip.equals(result.ip) : result.ip != null) return false;
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return hostname != null ? hostname.equals(result.hostname) : result.hostname == null;
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}
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@Override
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public int hashCode() {
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int result = ip != null ? ip.hashCode() : 0;
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result = 31 * result + (hostname != null ? hostname.hashCode() : 0);
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result = 31 * result + port;
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result = 31 * result + (directTls ? 1 : 0);
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result = 31 * result + (authenticated ? 1 : 0);
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result = 31 * result + priority;
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return result;
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}
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public InetAddress getIp() {
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return ip;
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}
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public int getPort() {
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return port;
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}
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public DNSName getHostname() {
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return hostname;
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}
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public boolean isDirectTls() {
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return directTls;
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}
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public boolean isAuthenticated() {
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return authenticated;
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}
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@Override
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public String toString() {
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return "Result{" +
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"ip='" + (ip == null ? null : ip.getHostAddress()) + '\'' +
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", hostame='" + (hostname == null ? null : hostname.toString()) + '\'' +
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", port=" + port +
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", directTls=" + directTls +
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", authenticated=" + authenticated +
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", priority=" + priority +
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'}';
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}
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@Override
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public int compareTo(@NonNull Result result) {
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if (result.priority == priority) {
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if (directTls == result.directTls) {
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if (ip == null && result.ip == null) {
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return 0;
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} else if (ip != null && result.ip != null) {
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if (ip instanceof Inet4Address && result.ip instanceof Inet4Address) {
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return 0;
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} else {
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return ip instanceof Inet4Address ? -1 : 1;
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}
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} else {
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return ip != null ? -1 : 1;
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}
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} else {
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return directTls ? -1 : 1;
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}
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} else {
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return priority - result.priority;
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}
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}
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public ContentValues toContentValues() {
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final ContentValues contentValues = new ContentValues();
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contentValues.put(IP, ip == null ? null : ip.getAddress());
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contentValues.put(HOSTNAME, hostname == null ? null : hostname.toString());
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contentValues.put(PORT, port);
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contentValues.put(PRIORITY, priority);
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contentValues.put(DIRECT_TLS, directTls ? 1 : 0);
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contentValues.put(AUTHENTICATED, authenticated ? 1 : 0);
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return contentValues;
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}
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}
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}
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