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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  import org.jboss.netty.util.CharsetUtil;
23  
24  /**
25   * Decodes {@link ChannelBuffer}s into {@link SocksAuthRequest}.
26   * Before returning SocksRequest decoder removes itself from pipeline.
27   */
28  public class SocksAuthRequestDecoder extends ReplayingDecoder<SocksAuthRequestDecoder.State> {
29  
30      private SocksMessage.SubnegotiationVersion version;
31      private int fieldLength;
32      private String username;
33      private String password;
34      private SocksRequest msg = SocksCommonUtils.UNKNOWN_SOCKS_REQUEST;
35  
36      public SocksAuthRequestDecoder() {
37          super(State.CHECK_PROTOCOL_VERSION);
38      }
39  
40      @Override
41      protected Object decode(ChannelHandlerContext ctx, Channel channel,
42                              ChannelBuffer buffer, State state) throws Exception {
43          switch (state) {
44              case CHECK_PROTOCOL_VERSION: {
45                  version = SocksMessage.SubnegotiationVersion.fromByte(buffer.readByte());
46                  if (version != SocksMessage.SubnegotiationVersion.AUTH_PASSWORD) {
47                      break;
48                  }
49                  checkpoint(State.READ_USERNAME);
50              }
51              case READ_USERNAME: {
52                  fieldLength = buffer.readByte();
53                  username = buffer.readBytes(fieldLength).toString(CharsetUtil.US_ASCII);
54                  checkpoint(State.READ_PASSWORD);
55              }
56              case READ_PASSWORD: {
57                  fieldLength = buffer.readByte();
58                  password = buffer.readBytes(fieldLength).toString(CharsetUtil.US_ASCII);
59                  msg = new SocksAuthRequest(username, password);
60              }
61          }
62          ctx.getPipeline().remove(this);
63          return msg;
64      }
65  
66      enum State {
67          CHECK_PROTOCOL_VERSION,
68          READ_USERNAME,
69          READ_PASSWORD
70      }
71  }