/*
* Copyright 2015-2025 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
* in compliance with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under the License
* is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
* or implied. See the License for the specific language governing permissions and limitations under
* the License.
*/
package sockslib.server;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sockslib.client.SocksProxy;
import sockslib.client.SocksSocket;
import sockslib.common.ProtocolErrorException;
import sockslib.common.SocksException;
import sockslib.common.methods.SocksMethod;
import sockslib.server.io.Pipe;
import sockslib.server.io.PipeListener;
import sockslib.server.io.SocketPipe;
import sockslib.server.msg.CommandMessage;
import sockslib.server.msg.CommandResponseMessage;
import sockslib.server.msg.MethodSelectionMessage;
import sockslib.server.msg.MethodSelectionResponseMessage;
import sockslib.server.msg.ServerReply;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
/**
* The class <code>Socks5Handler</code> represents a handler that can handle SOCKS5 protocol.
*
* @author Youchao Feng
* @version 1.0
* @date Apr 16, 2015 11:03:49 AM
*/
public class Socks5Handler implements SocksHandler {
/**
* Logger that subclasses also can use.
*/
protected static final Logger logger = LoggerFactory.getLogger(Socks5Handler.class);
/**
* Protocol version.
*/
private static final int VERSION = 0x5;
/**
* Session.
*/
private Session session;
/**
* Method selector.
*/
private MethodSelector methodSelector;
private int bufferSize;
private int idleTime = 2000;
private SocksProxy proxy;
private SocksProxyServer socksProxyServer;
private SessionManager sessionManager;
@Override
public void handle(Session session) throws Exception {
sessionManager = getSocksProxyServer().getSessionManager();
sessionManager.sessionOnCreate(session);
MethodSelectionMessage msg = new MethodSelectionMessage();
session.read(msg);
if (msg.getVersion() != VERSION) {
throw new ProtocolErrorException();
}
SocksMethod selectedMethod = methodSelector.select(msg);
logger.debug("SESSION[{}] Response client:{}", session.getId(), selectedMethod.getMethodName());
// send select method.
session.write(new MethodSelectionResponseMessage(VERSION, selectedMethod));
// do method.
selectedMethod.doMethod(session);
CommandMessage commandMessage = new CommandMessage();
session.read(commandMessage); // Read command request.
// logger.info("SESSION[{}] request:{} {}:{}", session.getId(), commandMessage.getCommand(),
// commandMessage.getAddressType() != AddressType.DOMAIN_NAME ?
// commandMessage.getInetAddress() :
// commandMessage.getHost(), commandMessage.getPort());
// If there is a SOCKS exception in command message, It will send a right response to client.
if (commandMessage.hasSocksException()) {
ServerReply serverReply = commandMessage.getSocksException().getServerReply();
session.write(new CommandResponseMessage(serverReply));
logger.info("SESSION[{}] will close, because {}", session.getId(), serverReply);
return;
}
/**************************** DO COMMAND ******************************************/
sessionManager.sessionOnCommand(session, commandMessage);
switch (commandMessage.getCommand()) {
case BIND:
doBind(session, commandMessage);
break;
case CONNECT:
doConnect(session, commandMessage);
break;
case UDP_ASSOCIATE:
doUDPAssociate(session, commandMessage);
break;
}
}
@Override
public void doConnect(Session session, CommandMessage commandMessage) throws SocksException,
IOException {
ServerReply reply = null;
Socket socket = null;
InetAddress bindAddress = null;
int bindPort = 0;
InetAddress remoteServerAddress = commandMessage.getInetAddress();
int remoteServerPort = commandMessage.getPort();
// set default bind address.
byte[] defaultAddress = {0, 0, 0, 0};
bindAddress = InetAddress.getByAddress(defaultAddress);
// DO connect
try {
// Connect directly.
if (proxy == null) {
socket = new Socket(remoteServerAddress, remoteServerPort);
} else {
socket = new SocksSocket(proxy, remoteServerAddress, remoteServerPort);
}
bindAddress = socket.getLocalAddress();
bindPort = socket.getLocalPort();
reply = ServerReply.SUCCEEDED;
} catch (IOException e) {
if (e.getMessage().equals("Connection refused")) {
reply = ServerReply.CONNECTION_REFUSED;
} else if (e.getMessage().equals("Operation timed out")) {
reply = ServerReply.TTL_EXPIRED;
} else if (e.getMessage().equals("Network is unreachable")) {
reply = ServerReply.NETWORK_UNREACHABLE;
} else if (e.getMessage().equals("Connection timed out")) {
reply = ServerReply.TTL_EXPIRED;
} else {
reply = ServerReply.GENERAL_SOCKS_SERVER_FAILURE;
}
logger.info("SESSION[{}] connect {} [{}] exception:{}", session.getId(), new
InetSocketAddress(remoteServerAddress, remoteServerPort), reply, e.getMessage());
}
CommandResponseMessage responseMessage =
new CommandResponseMessage(VERSION, reply, bindAddress, bindPort);
session.write(responseMessage);
if (reply != ServerReply.SUCCEEDED) { // 如果返回失败信息，则退出该方法。
session.close();
return;
}
Pipe pipe = new SocketPipe(session.getSocket(), socket);
pipe.setName("SESSION[" + session.getId() + "]");
pipe.setBufferSize(bufferSize);
if(getSocksProxyServer().getPipeInitializer() != null){
pipe = getSocksProxyServer().getPipeInitializer().initialize(pipe);
}
pipe.start(); // This method will build tow thread to run tow internal pipes.
// wait for pipe exit.
while (pipe.isRunning()) {
try {
Thread.sleep(idleTime);
} catch (InterruptedException e) {
pipe.stop();
session.close();
logger.info("SESSION[{}] closed", session.getId());
}
}
}
@Override
public void doBind(Session session, CommandMessage commandMessage) throws SocksException,
IOException {
ServerSocket serverSocket = new ServerSocket(commandMessage.getPort());
int bindPort = serverSocket.getLocalPort();
Socket socket = null;
logger.info("Create TCP server bind at {} for session[{}]", serverSocket
.getLocalSocketAddress(), session.getId());
session.write(new CommandResponseMessage(VERSION, ServerReply.SUCCEEDED, serverSocket
.getInetAddress(), bindPort));
socket = serverSocket.accept();
session.write(new CommandResponseMessage(VERSION, ServerReply.SUCCEEDED, socket
.getLocalAddress(), socket.getLocalPort()));
Pipe pipe = new SocketPipe(session.getSocket(), socket);
pipe.setBufferSize(bufferSize);
pipe.start();
// wait for pipe exit.
while (pipe.isRunning()) {
try {
Thread.sleep(idleTime);
} catch (InterruptedException e) {
pipe.stop();
session.close();
logger.info("Session[{}] closed", session.getId());
}
}
serverSocket.close();
// throw new NotImplementException("Not implement BIND command");
}
@Override
public void doUDPAssociate(Session session, CommandMessage commandMessage) throws
SocksException, IOException {
UDPRelayServer udpRelayServer =
new UDPRelayServer(((InetSocketAddress) session.getClientAddress()).getAddress(),
commandMessage.getPort());
InetSocketAddress socketAddress = (InetSocketAddress) udpRelayServer.start();
logger.info("Create UDP relay server at[{}] for {}", socketAddress, commandMessage
.getSocketAddress());
session.write(new CommandResponseMessage(VERSION, ServerReply.SUCCEEDED, InetAddress
.getLocalHost(), socketAddress.getPort()));
while (udpRelayServer.isRunning()) {
try {
Thread.sleep(idleTime);
} catch (InterruptedException e) {
session.close();
logger.info("Session[{}] closed", session.getId());
}
if (session.isClose()) {
udpRelayServer.stop();
logger.debug("UDP relay server for session[{}] is closed", session.getId());
}
}
}
@Override
public void setSession(Session session) {
this.session = session;
}
@Override
public void run() {
try {
handle(session);
} catch (Exception e) {
sessionManager.sessionOnException(session, e);
// logger.error("SESSION[{}]: {}", session.getId(), e.getMessage());
} finally {
session.close();
sessionManager.sessionOnClose(session);
// logger.info("SESSION[{}] closed, {}", session.getId(), session.getNetworkMonitor().toString
// ());
}
}
@Override
public MethodSelector getMethodSelector() {
return methodSelector;
}
@Override
public void setMethodSelector(MethodSelector methodSelector) {
this.methodSelector = methodSelector;
}
@Override
public int getBufferSize() {
return bufferSize;
}
@Override
public void setBufferSize(int bufferSize) {
this.bufferSize = bufferSize;
}
@Override
public int getIdleTime() {
return idleTime;
}
@Override
public void setIdleTime(int idleTime) {
this.idleTime = idleTime;
}
public SocksProxy getProxy() {
return proxy;
}
@Override
public void setProxy(SocksProxy proxy) {
this.proxy = proxy;
}
@Override
public SocksProxyServer getSocksProxyServer() {
return socksProxyServer;
}
@Override
public void setSocksProxyServer(SocksProxyServer socksProxyServer) {
this.socksProxyServer = socksProxyServer;
}
}