// compute digest
String digest = Socks5Utils.createDigest(sessionID, this.connection.getUser(), targetJID);
// prioritize last working SOCKS5 proxy if exists
if (this.proxyPrioritizationEnabled && this.lastWorkingProxy != null) {
StreamHost selectedStreamHost = null;
for (StreamHost streamHost : streamHosts) {
if (streamHost.getJID().equals(this.lastWorkingProxy)) {
selectedStreamHost = streamHost;
break;
}
}
if (selectedStreamHost != null) {
streamHosts.remove(selectedStreamHost);
streamHosts.add(0, selectedStreamHost);
}
}
Socks5Proxy socks5Proxy = Socks5Proxy.getSocks5Proxy();
try {
// add transfer digest to local proxy to make transfer valid
socks5Proxy.addTransfer(digest);
// create initiation packet
Bytestream initiation = createBytestreamInitiation(sessionID, targetJID, streamHosts);
// send initiation packet
Packet response = SyncPacketSend.getReply(this.connection, initiation,
getTargetResponseTimeout());
// extract used stream host from response
StreamHostUsed streamHostUsed = ((Bytestream) response).getUsedHost();
StreamHost usedStreamHost = initiation.getStreamHost(streamHostUsed.getJID());
if (usedStreamHost == null) {
throw new XMPPException("Remote user responded with unknown host");
}
// build SOCKS5 client
Socks5Client socks5Client = new Socks5ClientForInitiator(usedStreamHost, digest,
this.connection, sessionID, targetJID);
// establish connection to proxy
Socket socket = socks5Client.getSocket(getProxyConnectionTimeout());
// remember last working SOCKS5 proxy to prioritize it for next request
this.lastWorkingProxy = usedStreamHost.getJID();
// negotiation successful, return the output stream
return new Socks5BytestreamSession(socket, usedStreamHost.getJID().equals(
this.connection.getUser()));
}
catch (TimeoutException e) {
throw new IOException("Timeout while connecting to SOCKS5 proxy");