/**
* Encodes the authentication packet for supported authentication methods.
*
* @param request the socks proxy request data
* @return the encoded buffer, if null then authentication step is over and handshake process can
* jump immediately to the next step without waiting for a server reply.
* @throws UnsupportedEncodingException if some string charset convertion fails
* @throws GSSException when something fails while using GSSAPI
*/
private IoBuffer encodeAuthenticationPacket(final SocksProxyRequest request)
throws UnsupportedEncodingException, GSSException {
byte method = (Byte) getSession().getAttribute(Socks5LogicHandler.SELECTED_AUTH_METHOD);
switch (method) {
case SocksProxyConstants.NO_AUTH:
// In this case authentication is immediately considered as successfull
// Next writeRequest() call will send the proxy request
getSession().setAttribute(HANDSHAKE_STEP, SocksProxyConstants.SOCKS5_REQUEST_STEP);
break;
case SocksProxyConstants.GSSAPI_AUTH:
return encodeGSSAPIAuthenticationPacket(request);
case SocksProxyConstants.BASIC_AUTH:
// The basic auth scheme packet is sent
byte[] user = request.getUserName().getBytes("ASCII");
byte[] pwd = request.getPassword().getBytes("ASCII");
IoBuffer buf = IoBuffer.allocate(3 + user.length + pwd.length);
buf.put(SocksProxyConstants.BASIC_AUTH_SUBNEGOTIATION_VERSION);
buf.put((byte) user.length);
buf.put(user);
buf.put((byte) pwd.length);
buf.put(pwd);
return buf;
}
return null;
}
/**
* Encode a SOCKS4/SOCKS4a request and writes it to the next filter so it can be sent to the proxy
* server.
*
* @param nextFilter the next filter
* @param request the request to send.
*/
protected void writeRequest(final NextFilter nextFilter, final SocksProxyRequest request) {
try {
boolean isV4ARequest = Arrays.equals(request.getIpAddress(), SocksProxyConstants.FAKE_IP);
byte[] userID = request.getUserName().getBytes("ASCII");
byte[] host = isV4ARequest ? request.getHost().getBytes("ASCII") : null;
int len = 9 + userID.length;
if (isV4ARequest) {
len += host.length + 1;
}
IoBuffer buf = IoBuffer.allocate(len);
buf.put(request.getProtocolVersion());
buf.put(request.getCommandCode());
buf.put(request.getPort());
buf.put(request.getIpAddress());
buf.put(userID);
buf.put(SocksProxyConstants.TERMINATOR);
if (isV4ARequest) {
buf.put(host);
buf.put(SocksProxyConstants.TERMINATOR);
}
if (isV4ARequest) {
logger.debug(" sending SOCKS4a request");
} else {
logger.debug(" sending SOCKS4 request");
}
buf.flip();
writeData(nextFilter, buf);
} catch (Exception ex) {
closeSession("Unable to send Socks request: ", ex);
}
}
