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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 io.netty.handler.codec.socks;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.channel.ChannelHandlerContext;
20  import io.netty.handler.codec.ReplayingDecoder;
21  import io.netty.handler.codec.socks.SocksAuthRequestDecoder.State;
22  
23  import java.util.List;
24  
25  /**
26   * Decodes {@link ByteBuf}s into {@link SocksAuthRequest}.
27   * Before returning SocksRequest decoder removes itself from pipeline.
28   */
29  public class SocksAuthRequestDecoder extends ReplayingDecoder<State> {
30  
31      private String username;
32  
33      public SocksAuthRequestDecoder() {
34          super(State.CHECK_PROTOCOL_VERSION);
35      }
36  
37      @Override
38      protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> out) throws Exception {
39          switch (state()) {
40              case CHECK_PROTOCOL_VERSION: {
41                  if (byteBuf.readByte() != SocksSubnegotiationVersion.AUTH_PASSWORD.byteValue()) {
42                      out.add(SocksCommonUtils.UNKNOWN_SOCKS_REQUEST);
43                      break;
44                  }
45                  checkpoint(State.READ_USERNAME);
46              }
47              case READ_USERNAME: {
48                  int fieldLength = byteBuf.readByte();
49                  username = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
50                  checkpoint(State.READ_PASSWORD);
51              }
52              case READ_PASSWORD: {
53                  int fieldLength = byteBuf.readByte();
54                  String password = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
55                  out.add(new SocksAuthRequest(username, password));
56                  break;
57              }
58              default: {
59                  throw new Error();
60              }
61          }
62          ctx.pipeline().remove(this);
63      }
64  
65      enum State {
66          CHECK_PROTOCOL_VERSION,
67          READ_USERNAME,
68          READ_PASSWORD
69      }
70  }