Java tutorial
/* * 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.handler.codec.socks; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelHandlerContext; import io.netty.handler.codec.ReplayingDecoder; import io.netty.handler.codec.socks.SocksCmdResponseDecoder.State; import io.netty.util.NetUtil; import java.util.List; /** * Decodes {@link ByteBuf}s into {@link SocksCmdResponse}. * Before returning SocksResponse decoder removes itself from pipeline. */ public class SocksCmdResponseDecoder extends ReplayingDecoder<State> { private SocksCmdStatus cmdStatus; private SocksAddressType addressType; public SocksCmdResponseDecoder() { super(State.CHECK_PROTOCOL_VERSION); } @Override protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> out) throws Exception { switch (state()) { case CHECK_PROTOCOL_VERSION: { if (byteBuf.readByte() != SocksProtocolVersion.SOCKS5.byteValue()) { out.add(SocksCommonUtils.UNKNOWN_SOCKS_RESPONSE); break; } checkpoint(State.READ_CMD_HEADER); } case READ_CMD_HEADER: { cmdStatus = SocksCmdStatus.valueOf(byteBuf.readByte()); byteBuf.skipBytes(1); // reserved addressType = SocksAddressType.valueOf(byteBuf.readByte()); checkpoint(State.READ_CMD_ADDRESS); } case READ_CMD_ADDRESS: { switch (addressType) { case IPv4: { String host = NetUtil.intToIpAddress(byteBuf.readInt()); int port = byteBuf.readUnsignedShort(); out.add(new SocksCmdResponse(cmdStatus, addressType, host, port)); break; } case DOMAIN: { int fieldLength = byteBuf.readByte(); String host = SocksCommonUtils.readUsAscii(byteBuf, fieldLength); int port = byteBuf.readUnsignedShort(); out.add(new SocksCmdResponse(cmdStatus, addressType, host, port)); break; } case IPv6: { byte[] bytes = new byte[16]; byteBuf.readBytes(bytes); String host = SocksCommonUtils.ipv6toStr(bytes); int port = byteBuf.readUnsignedShort(); out.add(new SocksCmdResponse(cmdStatus, addressType, host, port)); break; } case UNKNOWN: { out.add(SocksCommonUtils.UNKNOWN_SOCKS_RESPONSE); break; } default: { throw new Error(); } } break; } default: { throw new Error(); } } ctx.pipeline().remove(this); } enum State { CHECK_PROTOCOL_VERSION, READ_CMD_HEADER, READ_CMD_ADDRESS } }