/*
* 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 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 = SocksCommonUtils.intToIp(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
}
}