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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.SocksAuthResponseDecoder.State;
22  
23  import java.util.List;
24  
25  /**
26   * Decodes {@link ByteBuf}s into {@link SocksAuthResponse}.
27   * Before returning SocksResponse decoder removes itself from pipeline.
28   */
29  public class SocksAuthResponseDecoder extends ReplayingDecoder<State> {
30      private static final String name = "SOCKS_AUTH_RESPONSE_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      public SocksAuthResponseDecoder() {
41          super(State.CHECK_PROTOCOL_VERSION);
42      }
43  
44      @Override
45      protected void decode(ChannelHandlerContext channelHandlerContext, ByteBuf byteBuf, List<Object> out)
46              throws Exception {
47          switch (state()) {
48              case CHECK_PROTOCOL_VERSION: {
49                  if (byteBuf.readByte() != SocksSubnegotiationVersion.AUTH_PASSWORD.byteValue()) {
50                      out.add(SocksCommonUtils.UNKNOWN_SOCKS_RESPONSE);
51                      break;
52                  }
53                  checkpoint(State.READ_AUTH_RESPONSE);
54              }
55              case READ_AUTH_RESPONSE: {
56                  SocksAuthStatus authStatus = SocksAuthStatus.valueOf(byteBuf.readByte());
57                  out.add(new SocksAuthResponse(authStatus));
58                  break;
59              }
60              default: {
61                  throw new Error();
62              }
63          }
64          channelHandlerContext.pipeline().remove(this);
65      }
66  
67      enum State {
68          CHECK_PROTOCOL_VERSION,
69          READ_AUTH_RESPONSE
70      }
71  }