io.netty.handler.codec.socksx.v4.Socks4ServerDecoder Maven / Gradle / Ivy

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/*
 * 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.socksx.v4;

import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.handler.codec.DecoderException;
import io.netty.handler.codec.DecoderResult;
import io.netty.handler.codec.ReplayingDecoder;
import io.netty.handler.codec.socksx.SocksVersion;
import io.netty.handler.codec.socksx.v4.Socks4ServerDecoder.State;
import io.netty.util.CharsetUtil;
import io.netty.util.NetUtil;

import java.util.List;

/**
 * Decodes a single {@link Socks4CommandRequest} from the inbound {@link ByteBuf}s.
 * On successful decode, this decoder will forward the received data to the next handler, so that
 * other handler can remove this decoder later.  On failed decode, this decoder will discard the
 * received data, so that other handler closes the connection later.
 */
public class Socks4ServerDecoder extends ReplayingDecoder {

    private static final int MAX_FIELD_LENGTH = 255;

    enum State {
        START,
        READ_USERID,
        READ_DOMAIN,
        SUCCESS,
        FAILURE
    }

    private Socks4CommandType type;
    private String dstAddr;
    private int dstPort;
    private String userId;

    public Socks4ServerDecoder() {
        super(State.START);
        setSingleDecode(true);
    }

    @Override
    protected void decode(ChannelHandlerContext ctx, ByteBuf in, List