/*
* 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
}
}