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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      private static final String name = "SOCKS_AUTH_REQUEST_DECODER";
31  
32      /**
33       * @deprecated Will be removed at the next minor version bump.
34       */
35      @Deprecated
36      public static String getName() {
37          return name;
38      }
39  
40      private String username;
41  
42      public SocksAuthRequestDecoder() {
43          super(State.CHECK_PROTOCOL_VERSION);
44      }
45  
46      @Override
47      protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> out) throws Exception {
48          switch (state()) {
49              case CHECK_PROTOCOL_VERSION: {
50                  if (byteBuf.readByte() != SocksSubnegotiationVersion.AUTH_PASSWORD.byteValue()) {
51                      out.add(SocksCommonUtils.UNKNOWN_SOCKS_REQUEST);
52                      break;
53                  }
54                  checkpoint(State.READ_USERNAME);
55              }
56              case READ_USERNAME: {
57                  int fieldLength = byteBuf.readByte();
58                  username = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
59                  checkpoint(State.READ_PASSWORD);
60              }
61              case READ_PASSWORD: {
62                  int fieldLength = byteBuf.readByte();
63                  String password = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
64                  out.add(new SocksAuthRequest(username, password));
65                  break;
66              }
67              default: {
68                  throw new Error();
69              }
70          }
71          ctx.pipeline().remove(this);
72      }
73  
74      enum State {
75          CHECK_PROTOCOL_VERSION,
76          READ_USERNAME,
77          READ_PASSWORD
78      }
79  }