/**
* Returns the response to the SOCKS5 Bytestream request containing the SOCKS5 proxy used.
*
* @param selectedHost the used SOCKS5 proxy
* @return the response to the SOCKS5 Bytestream request
*/
private Bytestream createUsedHostResponse(StreamHost selectedHost) {
Bytestream response = new Bytestream(this.bytestreamRequest.getSessionID());
response.setTo(this.bytestreamRequest.getFrom());
response.setType(IQ.Type.RESULT);
response.setPacketID(this.bytestreamRequest.getPacketID());
response.setUsedHost(selectedHost.getJID());
return response;
}
/**
* Accepts the SOCKS5 Bytestream initialization request and returns the socket to send/receive
* data.
*
* <p>Before accepting the SOCKS5 Bytestream request you can set timeouts by invoking {@link
* #setTotalConnectTimeout(int)} and {@link #setMinimumConnectTimeout(int)}.
*
* @return the socket to send/receive data
* @throws XMPPException if connection to all SOCKS5 proxies failed or if stream is invalid.
* @throws InterruptedException if the current thread was interrupted while waiting
*/
public Socks5BytestreamSession accept() throws XMPPException, InterruptedException {
Collection<StreamHost> streamHosts = this.bytestreamRequest.getStreamHosts();
// throw exceptions if request contains no stream hosts
if (streamHosts.size() == 0) {
cancelRequest();
}
StreamHost selectedHost = null;
Socket socket = null;
String digest =
Socks5Utils.createDigest(
this.bytestreamRequest.getSessionID(),
this.bytestreamRequest.getFrom(),
this.manager.getConnection().getUser());
/*
* determine timeout for each connection attempt; each SOCKS5 proxy has the same amount of
* time so that the first does not consume the whole timeout
*/
int timeout =
Math.max(getTotalConnectTimeout() / streamHosts.size(), getMinimumConnectTimeout());
for (StreamHost streamHost : streamHosts) {
String address = streamHost.getAddress() + ":" + streamHost.getPort();
// check to see if this address has been blacklisted
int failures = getConnectionFailures(address);
if (CONNECTION_FAILURE_THRESHOLD > 0 && failures >= CONNECTION_FAILURE_THRESHOLD) {
continue;
}
// establish socket
try {
// build SOCKS5 client
final Socks5Client socks5Client = new Socks5Client(streamHost, digest);
// connect to SOCKS5 proxy with a timeout
socket = socks5Client.getSocket(timeout);
// set selected host
selectedHost = streamHost;
break;
} catch (TimeoutException e) {
incrementConnectionFailures(address);
} catch (IOException e) {
incrementConnectionFailures(address);
} catch (XMPPException e) {
incrementConnectionFailures(address);
}
}
// throw exception if connecting to all SOCKS5 proxies failed
if (selectedHost == null || socket == null) {
cancelRequest();
}
// send used-host confirmation
Bytestream response = createUsedHostResponse(selectedHost);
this.manager.getConnection().sendPacket(response);
return new Socks5BytestreamSession(
socket, selectedHost.getJID().equals(this.bytestreamRequest.getFrom()));
}