/**
* Handle a SOCKS v5 response from the proxy server.
*
* @param nextFilter the next filter
* @param buf the buffered data received
* @param step the current step in the authentication process
*/
protected void handleResponse(final NextFilter nextFilter, final IoBuffer buf, int step)
throws Exception {
int len = 2;
if (step == SocksProxyConstants.SOCKS5_GREETING_STEP) {
// Send greeting message
byte method = buf.get(1);
if (method == SocksProxyConstants.NO_ACCEPTABLE_AUTH_METHOD) {
throw new IllegalStateException(
"No acceptable authentication method to use with " + "the socks proxy server");
}
getSession().setAttribute(SELECTED_AUTH_METHOD, method);
} else if (step == SocksProxyConstants.SOCKS5_AUTH_STEP) {
// Authentication to the SOCKS server
byte method = (Byte) getSession().getAttribute(Socks5LogicHandler.SELECTED_AUTH_METHOD);
if (method == SocksProxyConstants.GSSAPI_AUTH) {
int oldPos = buf.position();
if (buf.get(0) != 0x01) {
throw new IllegalStateException("Authentication failed");
}
if (buf.get(1) == 0xFF) {
throw new IllegalStateException(
"Authentication failed: GSS API Security Context Failure");
}
if (buf.remaining() >= 2) {
byte[] size = new byte[2];
buf.get(size);
int s = ByteUtilities.makeIntFromByte2(size);
if (buf.remaining() >= s) {
byte[] token = new byte[s];
buf.get(token);
getSession().setAttribute(GSS_TOKEN, token);
len = 0;
} else {
// buf.position(oldPos);
return;
}
} else {
buf.position(oldPos);
return;
}
} else if (buf.get(1) != SocksProxyConstants.V5_REPLY_SUCCEEDED) {
throw new IllegalStateException("Authentication failed");
}
} else if (step == SocksProxyConstants.SOCKS5_REQUEST_STEP) {
// Send the request
byte addressType = buf.get(3);
len = 6;
if (addressType == SocksProxyConstants.IPV6_ADDRESS_TYPE) {
len += 16;
} else if (addressType == SocksProxyConstants.IPV4_ADDRESS_TYPE) {
len += 4;
} else if (addressType == SocksProxyConstants.DOMAIN_NAME_ADDRESS_TYPE) {
len += 1 + (buf.get(4));
} else {
throw new IllegalStateException("Unknwon address type");
}
if (buf.remaining() >= len) {
// handle response
byte status = buf.get(1);
LOGGER.debug(" response status: {}", SocksProxyConstants.getReplyCodeAsString(status));
if (status == SocksProxyConstants.V5_REPLY_SUCCEEDED) {
buf.position(buf.position() + len);
setHandshakeComplete();
return;
}
throw new Exception(
"Proxy handshake failed - Code: 0x" + ByteUtilities.asHex(new byte[] {status}));
}
return;
}
if (len > 0) {
buf.position(buf.position() + len);
}
// Move to the handshaking next step if not in the middle of
// the authentication process
boolean isAuthenticating = false;
if (step == SocksProxyConstants.SOCKS5_AUTH_STEP) {
byte method = (Byte) getSession().getAttribute(Socks5LogicHandler.SELECTED_AUTH_METHOD);
if (method == SocksProxyConstants.GSSAPI_AUTH) {
GSSContext ctx = (GSSContext) getSession().getAttribute(GSS_CONTEXT);
if (ctx == null || !ctx.isEstablished()) {
isAuthenticating = true;
}
}
}
if (!isAuthenticating) {
getSession().setAttribute(HANDSHAKE_STEP, ++step);
}
doHandshake(nextFilter);
}
