/*
* Copyright 2015 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.socksx;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelPipeline;
import io.netty.handler.codec.ByteToMessageDecoder;
import io.netty.handler.codec.socksx.v4.Socks4ServerDecoder;
import io.netty.handler.codec.socksx.v4.Socks4ServerEncoder;
import io.netty.handler.codec.socksx.v5.Socks5AddressEncoder;
import io.netty.handler.codec.socksx.v5.Socks5InitialRequestDecoder;
import io.netty.handler.codec.socksx.v5.Socks5ServerEncoder;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.util.List;
/**
* Detects the version of the current SOCKS connection and initializes the pipeline with
* {@link Socks4ServerDecoder} or {@link Socks5InitialRequestDecoder}.
*/
public class SocksPortUnificationServerHandler extends ByteToMessageDecoder {
private static final InternalLogger logger =
InternalLoggerFactory.getInstance(SocksPortUnificationServerHandler.class);
private final Socks5ServerEncoder socks5encoder;
/**
* Creates a new instance with the default configuration.
*/
public SocksPortUnificationServerHandler() {
this(Socks5ServerEncoder.DEFAULT);
}
/**
* Creates a new instance with the specified {@link Socks5ServerEncoder}.
* This constructor is useful when a user wants to use an alternative {@link Socks5AddressEncoder}.
*/
public SocksPortUnificationServerHandler(Socks5ServerEncoder socks5encoder) {
if (socks5encoder == null) {
throw new NullPointerException("socks5encoder");
}
this.socks5encoder = socks5encoder;
}
@Override
protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
final int readerIndex = in.readerIndex();
if (in.writerIndex() == readerIndex) {
return;
}
ChannelPipeline p = ctx.pipeline();
final byte versionVal = in.getByte(readerIndex);
SocksVersion version = SocksVersion.valueOf(versionVal);
switch (version) {
case SOCKS4a:
logKnownVersion(ctx, version);
p.addAfter(ctx.name(), null, Socks4ServerEncoder.INSTANCE);
p.addAfter(ctx.name(), null, new Socks4ServerDecoder());
break;
case SOCKS5:
logKnownVersion(ctx, version);
p.addAfter(ctx.name(), null, socks5encoder);
p.addAfter(ctx.name(), null, new Socks5InitialRequestDecoder());
break;
default:
logUnknownVersion(ctx, versionVal);
in.skipBytes(in.readableBytes());
ctx.close();
return;
}
p.remove(this);
}
private static void logKnownVersion(ChannelHandlerContext ctx, SocksVersion version) {
logger.debug("{} Protocol version: {}({})", ctx.channel(), version);
}
private static void logUnknownVersion(ChannelHandlerContext ctx, byte versionVal) {
if (logger.isDebugEnabled()) {
logger.debug("{} Unknown protocol version: {}", ctx.channel(), versionVal & 0xFF);
}
}
}