103 lines
2.7 KiB
Go
103 lines
2.7 KiB
Go
package xmpp
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import (
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"crypto/sha1"
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"encoding/hex"
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"encoding/xml"
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"errors"
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"fmt"
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"io"
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"net"
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"time"
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)
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const componentStreamOpen = "<?xml version='1.0'?><stream:stream to='%s' xmlns='%s' xmlns:stream='%s'>"
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// Component implements an XMPP extension allowing to extend XMPP server
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// using external components. Component specifications are defined
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// in XEP-0114, XEP-0355 and XEP-0356.
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type Component struct {
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Host string
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Secret string
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// TCP level connection
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conn net.Conn
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// read / write
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socketProxy io.ReadWriter // TODO
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decoder *xml.Decoder
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}
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// handshake generates an authentication token based on StreamID and shared secret.
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func (c *Component) handshake(streamId string) string {
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// 1. Concatenate the Stream ID received from the server with the shared secret.
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concatStr := streamId + c.Secret
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// 2. Hash the concatenated string according to the SHA1 algorithm, i.e., SHA1( concat (sid, password)).
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h := sha1.New()
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h.Write([]byte(concatStr))
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hash := h.Sum(nil)
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// 3. Ensure that the hash output is in hexadecimal format, not binary or base64.
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// 4. Convert the hash output to all lowercase characters.
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encodedStr := hex.EncodeToString(hash)
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return encodedStr
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}
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// TODO Helper to prepare connection string
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func (c *Component) Connect(connStr string) error {
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var conn net.Conn
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var err error
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if conn, err = net.DialTimeout("tcp", connStr, time.Duration(5)*time.Second); err != nil {
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return err
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}
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c.conn = conn
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// 1. Send stream open tag
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if _, err := fmt.Fprintf(conn, componentStreamOpen, c.Host, NSComponent, NSStream); err != nil {
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return errors.New("cannot send stream open " + err.Error())
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}
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c.decoder = xml.NewDecoder(conn)
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// 2. Initialize xml decoder and extract streamID from reply
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streamId, err := initDecoder(c.decoder)
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if err != nil {
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return errors.New("cannot init decoder " + err.Error())
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}
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// 3. Authentication
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if _, err := fmt.Fprintf(conn, "<handshake>%s</handshake>", c.handshake(streamId)); err != nil {
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return errors.New("cannot send handshake " + err.Error())
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}
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// 4. Check server response for authentication
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name, val, err := next(c.decoder)
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if err != nil {
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return err
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}
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switch v := val.(type) {
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case *StreamError:
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return errors.New("handshake failed " + v.Error.Local)
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case *Handshake:
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return nil
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default:
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return errors.New("unexpected packet, got " + name.Local + " in " + name.Space)
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}
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panic("unreachable")
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}
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// ReadPacket reads next incoming XMPP packet
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// TODO use defined interface Packet
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func (c *Component) ReadPacket() (xml.Name, interface{}, error) {
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return next(c.decoder)
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}
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// ============================================================================
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// XMPP packets struct
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type Handshake struct {
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XMLName xml.Name `xml:"jabber:component:accept handshake"`
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}
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