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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    *   https://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  import io.netty.util.internal.UnstableApi;
23  
24  import java.util.List;
25  
26  /**
27   * Decodes {@link ByteBuf}s into {@link SocksAuthRequest}.
28   * Before returning SocksRequest decoder removes itself from pipeline.
29   */
30  public class SocksAuthRequestDecoder extends ReplayingDecoder<State> {
31  
32      private String username;
33  
34      public SocksAuthRequestDecoder() {
35          super(State.CHECK_PROTOCOL_VERSION);
36      }
37  
38      @Override
39      protected void decode(ChannelHandlerContext ctx, ByteBuf byteBuf, List<Object> out) throws Exception {
40          switch (state()) {
41              case CHECK_PROTOCOL_VERSION: {
42                  if (byteBuf.readByte() != SocksSubnegotiationVersion.AUTH_PASSWORD.byteValue()) {
43                      out.add(SocksCommonUtils.UNKNOWN_SOCKS_REQUEST);
44                      break;
45                  }
46                  checkpoint(State.READ_USERNAME);
47              }
48              case READ_USERNAME: {
49                  int fieldLength = byteBuf.readByte();
50                  username = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
51                  checkpoint(State.READ_PASSWORD);
52              }
53              case READ_PASSWORD: {
54                  int fieldLength = byteBuf.readByte();
55                  String password = SocksCommonUtils.readUsAscii(byteBuf, fieldLength);
56                  out.add(new SocksAuthRequest(username, password));
57                  break;
58              }
59              default: {
60                  throw new Error();
61              }
62          }
63          ctx.pipeline().remove(this);
64      }
65  
66      @UnstableApi
67      public enum State {
68          CHECK_PROTOCOL_VERSION,
69          READ_USERNAME,
70          READ_PASSWORD
71      }
72  }