使用java实现的socket代理(支持socket4和socket5)

import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.nio.ByteBuffer;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.concurrent.CountDownLatch;

/**
 * Created with Intellij IDEA
 *
 * @author: jiaoyiping
 * Mail: [email protected]
 * Date: 2018/03/01
 * Time: 22:08
 * To change this template use File | Settings | Editor | File and Code Templates
 */

public class MySocket5Server implements Runnable {
private static final int SOCKS_PROTOCOL_4 = 0X04;
private static final int SOCKS_PROTOCOL_5 = 0X05;
private static final int DEFAULT_BUFFER_SIZE = 1024;
private static final byte TYPE_IPV4 = 0x01;
private static final byte TYPE_IPV6 = 0X02;
private static final byte TYPE_HOST = 0X03;
private static final byte ALLOW_PROXY = 0X5A;
private static final byte DENY_PROXY = 0X5B;
private Socket sourceSocket;

@Override
public void run() {
    String remoteAddress = sourceSocket.getRemoteSocketAddress().toString();
    log("process socket:" + remoteAddress);
    InputStream sourceIn = null, proxyIn = null;
    OutputStream sourceOut = null, proxyOut = null;

    Socket proxySocket = null;
    try {
        sourceIn = sourceSocket.getInputStream();
        sourceOut = sourceSocket.getOutputStream();
        //从协议头中获取socket的类型
        byte[] tmp = new byte[1];
        int n = sourceIn.read(tmp);
        if (n == 1) {
            int protocol = tmp[0];
            //socket4
            if (SOCKS_PROTOCOL_4 == protocol) {
                proxySocket = convertToSocket4(sourceIn, sourceOut);

            } else if (SOCKS_PROTOCOL_5 == protocol) {
                proxySocket = convertToSocket5(sourceIn, sourceOut);
            } else {
                log("Socket协议错误,不是Socket4或者Socket5");
            }
            //socket转换
            if (null != proxySocket) {
                CountDownLatch countDownLatch = new CountDownLatch(1);
                proxyIn = proxySocket.getInputStream();
                proxyOut = proxySocket.getOutputStream();
                transfer(sourceIn, proxyOut, countDownLatch);
                transfer(proxyIn, sourceOut, countDownLatch);
                try {
                    countDownLatch.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }

        } else {
            log("SOCKET ERROR: " + tmp.toString());
        }

    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        closeIO(sourceIn);
        closeIO(proxyIn);
        closeIO(proxyOut);
        closeIO(proxyIn);
        closeIO(proxySocket);
        closeIO(sourceSocket);
    }

}

public MySocket5Server(Socket sourceSocket) {
    this.sourceSocket = sourceSocket;
}

private static final void log(String message) {
    DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    System.out.println(dateFormat.format(new Date()) + " - " + message);
}

private static void startServer(int port) {
    log("config =>> port=" + port);
    try (ServerSocket serverSocket = new ServerSocket(port)) {
        Socket socket = null;
        while ((socket = serverSocket.accept()) != null) {
            new Thread(new MySocket5Server(socket)).start();
        }
        log("close socket(this never happen)");
    } catch (IOException e) {
        e.printStackTrace();
    }

}

private Socket convertToSocket4(InputStream inputStream, OutputStream outputStream) throws IOException {
    Socket proxySocket = null;
    byte[] tmp = new byte[3];
    inputStream.read(tmp);
    // 请求协议|VN1|CD1|DSTPORT2|DSTIP4|NULL1|
    int port = ByteBuffer.wrap(tmp, 1, 2).asShortBuffer().get() & 0xFFFF;
    String host = getHost((byte) 0x01, inputStream);
    inputStream.read();
    //返回一个8字节的响应协议: |VN1|CD1|DSTPORT2|DSTIP 4|
    byte[] response = new byte[8];
    try {
        proxySocket = new Socket(host, port);
        response[1] = ALLOW_PROXY;
        log("connect " + tmp[1] + "host: " + host + " ,port: " + port);
    } catch (Exception e) {
        response[1] = DENY_PROXY;
        log("connect error,host: " + host + " ,port: " + port);
    }
    outputStream.write(response);
    outputStream.flush();

    return proxySocket;
}

private Socket convertToSocket5(InputStream inputStream, OutputStream outputStream) throws IOException {
    Socket proxySocket = null;
    //处理SOCKS5头信息(不支持登录)
    byte[] tmp = new byte[2];
    inputStream.read(tmp);
    byte method = tmp[1];
    if (0x02 == tmp[0]) {
        method = 0x00;
        inputStream.read();
    }
    tmp = new byte[]{0x05, method};
    outputStream.write(tmp);
    outputStream.flush();

    byte cmd = 0;
    tmp = new byte[4];
    inputStream.read(tmp);
    log("proxy header is:" + Arrays.toString(tmp));

    cmd = tmp[1];
    String host = getHost(tmp[3], inputStream);
    tmp = new byte[2];
    inputStream.read(tmp);
    int port = ByteBuffer.wrap(tmp).asShortBuffer().get() & 0xFFFF;
    log("connect host: " + host + " :port:" + port);
    ByteBuffer rsv = ByteBuffer.allocate(10);
    rsv.put((byte) 0x05);
    Object resultTmp = null;
    try {
        if (0x01 == cmd) {
            resultTmp = new Socket(host, port);
            rsv.put((byte) 0x00);
        } else if (0x02 == cmd) {
            resultTmp = new ServerSocket(port);
            rsv.put((byte) 0x00);
        } else {
            rsv.put((byte) 0x05);
            resultTmp = null;
        }
    } catch (Exception e) {
        rsv.put((byte) 0x05);
        resultTmp = null;
    }
    rsv.put((byte) 0x00);
    rsv.put((byte) 0x01);
    rsv.put(sourceSocket.getLocalAddress().getAddress());
    Short localPort = (short) ((sourceSocket.getLocalPort()) & 0xFFFF);
    rsv.putShort(localPort);
    tmp = rsv.array();

    outputStream.write(tmp);
    outputStream.flush();
    if (null != resultTmp && 0x02 == cmd) {
        ServerSocket ss = (ServerSocket) resultTmp;
        try {
            resultTmp = ss.accept();
        } catch (Exception e) {
        } finally {
            closeIO(ss);
        }
    }
    return (Socket) resultTmp;

}

private void transfer(InputStream in, OutputStream out, CountDownLatch latch) {
    new Thread(() -> {
        byte[] bytes = new byte[DEFAULT_BUFFER_SIZE];
        int count = 0;
        try {
            while (0 < (count = in.read(bytes))) {
                out.write(bytes, 0, count);
                out.flush();
            }
        } catch (IOException e) {
            log("转换出现错误");
            e.printStackTrace();
        }
        if (latch != null) {
            latch.countDown();
        }

    }).start();

}

private void closeIO(Closeable closeable) {
    if (closeable != null) {
        try {
            closeable.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

private String getHost(byte type, InputStream inputStream) throws IOException {
    String host = null;
    byte[] tmp = null;
    switch (type) {
        case TYPE_IPV4:
            tmp = new byte[4];
            inputStream.read(tmp);
            host = InetAddress.getByAddress(tmp).getHostAddress();
            break;
        case TYPE_IPV6:
            tmp = new byte[16];
            inputStream.read(tmp);
            host = InetAddress.getByAddress(tmp).getHostAddress();
            break;
        case TYPE_HOST:
            int count = inputStream.read();
            tmp = new byte[count];
            inputStream.read(tmp);
            host = new String(tmp);
        default:
            break;
    }
    return host;
}

public static void main(String[] args) {
    java.security.Security.setProperty("networkaddress.cache.ttl", "86400");
    MySocket5Server.startServer(1033);
}

}

原文地址：https://www.cnblogs.com/jiaoyiping/p/8511962.html