Java example source code file (Socks5ProxyServer.java)

This example Java source code file (Socks5ProxyServer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

decoder, exception, inetsocketaddress, net, network, object, override, socks5commandrequest, socks5commandrequestdecoder, socks5commandresponse, socks5initialrequestdecoder, socks5intermediaryhandler, socks5passwordauthrequest, socks5passwordauthrequestdecoder, socks5proxyserver, string

The Socks5ProxyServer.java Java example source code

/*
 * Copyright 2014 The Netty Project
 *
 * The Netty Project licenses this file to you 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 io.netty.handler.proxy;

import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.LineBasedFrameDecoder;
import io.netty.handler.codec.socksx.v5.DefaultSocks5CommandResponse;
import io.netty.handler.codec.socksx.v5.DefaultSocks5InitialResponse;
import io.netty.handler.codec.socksx.v5.DefaultSocks5PasswordAuthResponse;
import io.netty.handler.codec.socksx.v5.Socks5AddressType;
import io.netty.handler.codec.socksx.v5.Socks5AuthMethod;
import io.netty.handler.codec.socksx.v5.Socks5CommandRequest;
import io.netty.handler.codec.socksx.v5.Socks5CommandRequestDecoder;
import io.netty.handler.codec.socksx.v5.Socks5CommandResponse;
import io.netty.handler.codec.socksx.v5.Socks5CommandStatus;
import io.netty.handler.codec.socksx.v5.Socks5CommandType;
import io.netty.handler.codec.socksx.v5.Socks5InitialRequest;
import io.netty.handler.codec.socksx.v5.Socks5InitialRequestDecoder;
import io.netty.handler.codec.socksx.v5.Socks5PasswordAuthRequest;
import io.netty.handler.codec.socksx.v5.Socks5PasswordAuthRequestDecoder;
import io.netty.handler.codec.socksx.v5.Socks5PasswordAuthStatus;
import io.netty.handler.codec.socksx.v5.Socks5ServerEncoder;
import io.netty.util.CharsetUtil;

import java.net.InetSocketAddress;
import java.net.SocketAddress;

import static org.hamcrest.Matchers.*;
import static org.junit.Assert.*;

final class Socks5ProxyServer extends ProxyServer {

    private static final String ENCODER = "encoder";
    private static final String DECODER = "decoder";

    Socks5ProxyServer(boolean useSsl, TestMode testMode, InetSocketAddress destination) {
        super(useSsl, testMode, destination);
    }

    Socks5ProxyServer(
            boolean useSsl, TestMode testMode, InetSocketAddress destination, String username, String password) {
        super(useSsl, testMode, destination, username, password);
    }

    @Override
    protected void configure(SocketChannel ch) throws Exception {
        ChannelPipeline p = ch.pipeline();
        switch (testMode) {
        case INTERMEDIARY:
            p.addLast(DECODER, new Socks5InitialRequestDecoder());
            p.addLast(ENCODER, Socks5ServerEncoder.DEFAULT);
            p.addLast(new Socks5IntermediaryHandler());
            break;
        case TERMINAL:
            p.addLast(DECODER, new Socks5InitialRequestDecoder());
            p.addLast(ENCODER, Socks5ServerEncoder.DEFAULT);
            p.addLast(new Socks5TerminalHandler());
            break;
        case UNRESPONSIVE:
            p.addLast(UnresponsiveHandler.INSTANCE);
            break;
        }
    }

    boolean authenticate(ChannelHandlerContext ctx, Object msg) {
        if (username == null) {
            ctx.pipeline().replace(DECODER, DECODER, new Socks5CommandRequestDecoder());
            ctx.write(new DefaultSocks5InitialResponse(Socks5AuthMethod.NO_AUTH));
            return true;
        }

        if (msg instanceof Socks5InitialRequest) {
            ctx.pipeline().replace(DECODER, DECODER, new Socks5PasswordAuthRequestDecoder());
            ctx.write(new DefaultSocks5InitialResponse(Socks5AuthMethod.PASSWORD));
            return false;
        }

        Socks5PasswordAuthRequest req = (Socks5PasswordAuthRequest) msg;
        if (req.username().equals(username) && req.password().equals(password)) {
            ctx.pipeline().replace(DECODER, DECODER, new Socks5CommandRequestDecoder());
            ctx.write(new DefaultSocks5PasswordAuthResponse(Socks5PasswordAuthStatus.SUCCESS));
            return true;
        }

        ctx.pipeline().replace(DECODER, DECODER, new Socks5PasswordAuthRequestDecoder());
        ctx.write(new DefaultSocks5PasswordAuthResponse(Socks5PasswordAuthStatus.FAILURE));
        return false;
    }

    private final class Socks5IntermediaryHandler extends IntermediaryHandler {

        private boolean authenticated;
        private SocketAddress intermediaryDestination;

        @Override
        protected boolean handleProxyProtocol(ChannelHandlerContext ctx, Object msg) throws Exception {
            if (!authenticated) {
                authenticated = authenticate(ctx, msg);
                return false;
            }

            Socks5CommandRequest req = (Socks5CommandRequest) msg;
            assertThat(req.type(), is(Socks5CommandType.CONNECT));

            Socks5CommandResponse res =
                    new DefaultSocks5CommandResponse(Socks5CommandStatus.SUCCESS, Socks5AddressType.IPv4);
            intermediaryDestination = new InetSocketAddress(req.dstAddr(), req.dstPort());

            ctx.write(res);

            ctx.pipeline().remove(ENCODER);
            ctx.pipeline().remove(DECODER);

            return true;
        }

        @Override
        protected SocketAddress intermediaryDestination() {
            return intermediaryDestination;
        }
    }

    private final class Socks5TerminalHandler extends TerminalHandler {

        private boolean authenticated;

        @Override
        protected boolean handleProxyProtocol(ChannelHandlerContext ctx, Object msg) throws Exception {
            if (!authenticated) {
                authenticated = authenticate(ctx, msg);
                return false;
            }

            Socks5CommandRequest req = (Socks5CommandRequest) msg;
            assertThat(req.type(), is(Socks5CommandType.CONNECT));

            ctx.pipeline().addBefore(ctx.name(), "lineDecoder", new LineBasedFrameDecoder(64, false, true));

            Socks5CommandResponse res;
            boolean sendGreeting = false;
            if (!req.dstAddr().equals(destination.getHostString()) ||
                       req.dstPort() != destination.getPort()) {
                res = new DefaultSocks5CommandResponse(Socks5CommandStatus.FORBIDDEN, Socks5AddressType.IPv4);
            } else {
                res = new DefaultSocks5CommandResponse(Socks5CommandStatus.SUCCESS, Socks5AddressType.IPv4);
                sendGreeting = true;
            }

            ctx.write(res);

            ctx.pipeline().remove(ENCODER);
            ctx.pipeline().remove(DECODER);

            if (sendGreeting) {
                ctx.write(Unpooled.copiedBuffer("0\n", CharsetUtil.US_ASCII));
            }

            return true;
        }
    }
}