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1   /*
2    * Copyright 2012 The Netty Project
3    *
4    * The Netty Project licenses this file to you under the Apache License,
5    * version 2.0 (the "License"); you may not use this file except in compliance
6    * with the License. You may obtain a copy of the License at:
7    *
8    *   http://www.apache.org/licenses/LICENSE-2.0
9    *
10   * Unless required by applicable law or agreed to in writing, software
11   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13   * License for the specific language governing permissions and limitations
14   * under the License.
15   */
16  package org.jboss.netty.handler.codec.socks;
17  
18  import org.jboss.netty.buffer.ChannelBuffer;
19  import org.jboss.netty.channel.Channel;
20  import org.jboss.netty.channel.ChannelHandlerContext;
21  import org.jboss.netty.handler.codec.replay.ReplayingDecoder;
22  
23  /**
24   * Decodes {@link ChannelBuffer}s into {@link SocksAuthResponse}.
25   * Before returning SocksResponse decoder removes itself from pipeline.
26   */
27  public class SocksAuthResponseDecoder extends ReplayingDecoder<SocksAuthResponseDecoder.State> {
28  
29      private SocksMessage.SubnegotiationVersion version;
30      private SocksMessage.AuthStatus authStatus;
31      private SocksResponse msg = SocksCommonUtils.UNKNOWN_SOCKS_RESPONSE;
32  
33      public SocksAuthResponseDecoder() {
34          super(State.CHECK_PROTOCOL_VERSION);
35      }
36  
37      @Override
38      protected Object decode(ChannelHandlerContext ctx, Channel channel,
39                              ChannelBuffer buffer, State state) throws Exception {
40          switch (state) {
41              case CHECK_PROTOCOL_VERSION: {
42                  version = SocksMessage.SubnegotiationVersion.fromByte(buffer.readByte());
43                  if (version != SocksMessage.SubnegotiationVersion.AUTH_PASSWORD) {
44                      break;
45                  }
46                  checkpoint(State.READ_AUTH_RESPONSE);
47              }
48              case READ_AUTH_RESPONSE: {
49                  authStatus = SocksMessage.AuthStatus.fromByte(buffer.readByte());
50                  msg = new SocksAuthResponse(authStatus);
51              }
52          }
53          ctx.getPipeline().remove(this);
54          return msg;
55      }
56  
57      public enum State {
58          CHECK_PROTOCOL_VERSION,
59          READ_AUTH_RESPONSE
60      }
61  }