Java example source code file (SocksServerConnectHandler.java)

This example Java source code file (SocksServerConnectHandler.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.

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Java - Java tags/keywords

bootstrap, channel, channelfuturelistener, channelhandlercontext, defaultsocks5commandresponse, directclienthandler, exception, override, promise, relayhandler, simplechannelinboundhandler, socks4commandrequest, socks5commandrequest, throwable

The SocksServerConnectHandler.java Java example source code

/*
 * Copyright 2012 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.example.socksproxy;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandler;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelOption;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.socksx.SocksMessage;
import io.netty.handler.codec.socksx.v4.DefaultSocks4CommandResponse;
import io.netty.handler.codec.socksx.v4.Socks4CommandRequest;
import io.netty.handler.codec.socksx.v4.Socks4CommandStatus;
import io.netty.handler.codec.socksx.v5.DefaultSocks5CommandResponse;
import io.netty.handler.codec.socksx.v5.Socks5CommandRequest;
import io.netty.handler.codec.socksx.v5.Socks5CommandStatus;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.FutureListener;
import io.netty.util.concurrent.Promise;

@ChannelHandler.Sharable
public final class SocksServerConnectHandler extends SimpleChannelInboundHandler<SocksMessage> {

    private final Bootstrap b = new Bootstrap();

    @Override
    public void channelRead0(final ChannelHandlerContext ctx, final SocksMessage message) throws Exception {
        if (message instanceof Socks4CommandRequest) {
            final Socks4CommandRequest request = (Socks4CommandRequest) message;
            Promise<Channel> promise = ctx.executor().newPromise();
            promise.addListener(
                    new FutureListener<Channel>() {
                        @Override
                        public void operationComplete(final Future<Channel> future) throws Exception {
                            final Channel outboundChannel = future.getNow();
                            if (future.isSuccess()) {
                                ChannelFuture responseFuture = ctx.channel().writeAndFlush(
                                        new DefaultSocks4CommandResponse(Socks4CommandStatus.SUCCESS));

                                responseFuture.addListener(new ChannelFutureListener() {
                                    @Override
                                    public void operationComplete(ChannelFuture channelFuture) {
                                        ctx.pipeline().remove(SocksServerConnectHandler.this);
                                        outboundChannel.pipeline().addLast(new RelayHandler(ctx.channel()));
                                        ctx.pipeline().addLast(new RelayHandler(outboundChannel));
                                    }
                                });
                            } else {
                                ctx.channel().writeAndFlush(
                                        new DefaultSocks4CommandResponse(Socks4CommandStatus.REJECTED_OR_FAILED));
                                SocksServerUtils.closeOnFlush(ctx.channel());
                            }
                        }
                    });

            final Channel inboundChannel = ctx.channel();
            b.group(inboundChannel.eventLoop())
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
                    .option(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new DirectClientHandler(promise));

            b.connect(request.dstAddr(), request.dstPort()).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (future.isSuccess()) {
                        // Connection established use handler provided results
                    } else {
                        // Close the connection if the connection attempt has failed.
                        ctx.channel().writeAndFlush(
                                new DefaultSocks4CommandResponse(Socks4CommandStatus.REJECTED_OR_FAILED)
                        );
                        SocksServerUtils.closeOnFlush(ctx.channel());
                    }
                }
            });
        } else if (message instanceof Socks5CommandRequest) {
            final Socks5CommandRequest request = (Socks5CommandRequest) message;
            Promise<Channel> promise = ctx.executor().newPromise();
            promise.addListener(
                    new FutureListener<Channel>() {
                        @Override
                        public void operationComplete(final Future<Channel> future) throws Exception {
                            final Channel outboundChannel = future.getNow();
                            if (future.isSuccess()) {
                                ChannelFuture responseFuture =
                                        ctx.channel().writeAndFlush(new DefaultSocks5CommandResponse(
                                                Socks5CommandStatus.SUCCESS, request.dstAddrType()));

                                responseFuture.addListener(new ChannelFutureListener() {
                                    @Override
                                    public void operationComplete(ChannelFuture channelFuture) {
                                        ctx.pipeline().remove(SocksServerConnectHandler.this);
                                        outboundChannel.pipeline().addLast(new RelayHandler(ctx.channel()));
                                        ctx.pipeline().addLast(new RelayHandler(outboundChannel));
                                    }
                                });
                            } else {
                                ctx.channel().writeAndFlush(new DefaultSocks5CommandResponse(
                                        Socks5CommandStatus.FAILURE, request.dstAddrType()));
                                SocksServerUtils.closeOnFlush(ctx.channel());
                            }
                        }
                    });

            final Channel inboundChannel = ctx.channel();
            b.group(inboundChannel.eventLoop())
                    .channel(NioSocketChannel.class)
                    .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 10000)
                    .option(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new DirectClientHandler(promise));

            b.connect(request.dstAddr(), request.dstPort()).addListener(new ChannelFutureListener() {
                @Override
                public void operationComplete(ChannelFuture future) throws Exception {
                    if (future.isSuccess()) {
                        // Connection established use handler provided results
                    } else {
                        // Close the connection if the connection attempt has failed.
                        ctx.channel().writeAndFlush(
                                new DefaultSocks5CommandResponse(Socks5CommandStatus.FAILURE, request.dstAddrType()));
                        SocksServerUtils.closeOnFlush(ctx.channel());
                    }
                }
            });
        } else {
            ctx.close();
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        SocksServerUtils.closeOnFlush(ctx.channel());
    }
}