Java tutorial
/* * Copyright 2017 ZhangJiupeng * * 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 cc.agentx.client.net.nio; import io.netty.buffer.Unpooled; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.socks.*; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; @ChannelHandler.Sharable public final class Socks5Handler extends SimpleChannelInboundHandler<SocksRequest> { private static final InternalLogger log = InternalLoggerFactory.getInstance(Socks5Handler.class); @Override public void channelRead0(ChannelHandlerContext ctx, SocksRequest request) throws Exception { switch (request.protocolVersion()) { case SOCKS4a: log.warn("\tBad Handshake! (protocol version not supported: 4)"); ctx.write(new SocksInitResponse(SocksAuthScheme.UNKNOWN)); if (ctx.channel().isActive()) { ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); } break; case SOCKS5: switch (request.requestType()) { case INIT: ctx.pipeline().addFirst(new SocksCmdRequestDecoder()); ctx.write(new SocksInitResponse(SocksAuthScheme.NO_AUTH)); break; case AUTH: ctx.pipeline().addFirst(new SocksCmdRequestDecoder()); ctx.write(new SocksAuthResponse(SocksAuthStatus.SUCCESS)); break; case CMD: if (((SocksCmdRequest) request).cmdType() == SocksCmdType.CONNECT) { ctx.pipeline().addLast(new XConnectHandler()); ctx.pipeline().remove(this); ctx.fireChannelRead(request); } else { ctx.close(); log.warn("\tBad Handshake! (command not support: {})", ((SocksCmdRequest) request).cmdType()); } break; case UNKNOWN: log.warn("\tBad Handshake! (unknown request type)"); } break; case UNKNOWN: log.warn("\tBad Handshake! (protocol version not support: {}", request.protocolVersion()); ctx.close(); break; } } @Override public void channelReadComplete(ChannelHandlerContext ctx) { ctx.flush(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable throwable) { throwable.printStackTrace(); if (ctx.channel().isActive()) { ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); } } }