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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.example.portunification;
17  
18  import io.netty.buffer.ByteBuf;
19  import io.netty.channel.ChannelHandlerContext;
20  import io.netty.channel.ChannelPipeline;
21  import io.netty.example.factorial.BigIntegerDecoder;
22  import io.netty.example.factorial.FactorialServerHandler;
23  import io.netty.example.factorial.NumberEncoder;
24  import io.netty.example.http.snoop.HttpSnoopServerHandler;
25  import io.netty.handler.codec.ByteToMessageDecoder;
26  import io.netty.handler.codec.compression.ZlibCodecFactory;
27  import io.netty.handler.codec.compression.ZlibWrapper;
28  import io.netty.handler.codec.http.HttpContentCompressor;
29  import io.netty.handler.codec.http.HttpRequestDecoder;
30  import io.netty.handler.codec.http.HttpResponseEncoder;
31  import io.netty.handler.ssl.SslContext;
32  import io.netty.handler.ssl.SslHandler;
33  
34  import java.util.List;
35  
36  /**
37   * Manipulates the current pipeline dynamically to switch protocols or enable
38   * SSL or GZIP.
39   */
40  public class PortUnificationServerHandler extends ByteToMessageDecoder {
41  
42      private final SslContext sslCtx;
43      private final boolean detectSsl;
44      private final boolean detectGzip;
45  
46      public PortUnificationServerHandler(SslContext sslCtx) {
47          this(sslCtx, true, true);
48      }
49  
50      private PortUnificationServerHandler(SslContext sslCtx, boolean detectSsl, boolean detectGzip) {
51          this.sslCtx = sslCtx;
52          this.detectSsl = detectSsl;
53          this.detectGzip = detectGzip;
54      }
55  
56      @Override
57      protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
58          // Will use the first five bytes to detect a protocol.
59          if (in.readableBytes() < 5) {
60              return;
61          }
62  
63          if (isSsl(in)) {
64              enableSsl(ctx);
65          } else {
66              final int magic1 = in.getUnsignedByte(in.readerIndex());
67              final int magic2 = in.getUnsignedByte(in.readerIndex() + 1);
68              if (isGzip(magic1, magic2)) {
69                  enableGzip(ctx);
70              } else if (isHttp(magic1, magic2)) {
71                  switchToHttp(ctx);
72              } else if (isFactorial(magic1)) {
73                  switchToFactorial(ctx);
74              } else {
75                  // Unknown protocol; discard everything and close the connection.
76                  in.clear();
77                  ctx.close();
78              }
79          }
80      }
81  
82      private boolean isSsl(ByteBuf buf) {
83          if (detectSsl) {
84              return SslHandler.isEncrypted(buf);
85          }
86          return false;
87      }
88  
89      private boolean isGzip(int magic1, int magic2) {
90          if (detectGzip) {
91              return magic1 == 31 && magic2 == 139;
92          }
93          return false;
94      }
95  
96      private static boolean isHttp(int magic1, int magic2) {
97          return
98              magic1 == 'G' && magic2 == 'E' || // GET
99              magic1 == 'P' && magic2 == 'O' || // POST
100             magic1 == 'P' && magic2 == 'U' || // PUT
101             magic1 == 'H' && magic2 == 'E' || // HEAD
102             magic1 == 'O' && magic2 == 'P' || // OPTIONS
103             magic1 == 'P' && magic2 == 'A' || // PATCH
104             magic1 == 'D' && magic2 == 'E' || // DELETE
105             magic1 == 'T' && magic2 == 'R' || // TRACE
106             magic1 == 'C' && magic2 == 'O';   // CONNECT
107     }
108 
109     private static boolean isFactorial(int magic1) {
110         return magic1 == 'F';
111     }
112 
113     private void enableSsl(ChannelHandlerContext ctx) {
114         ChannelPipeline p = ctx.pipeline();
115         p.addLast("ssl", sslCtx.newHandler(ctx.alloc()));
116         p.addLast("unificationA", new PortUnificationServerHandler(sslCtx, false, detectGzip));
117         p.remove(this);
118     }
119 
120     private void enableGzip(ChannelHandlerContext ctx) {
121         ChannelPipeline p = ctx.pipeline();
122         p.addLast("gzipdeflater", ZlibCodecFactory.newZlibEncoder(ZlibWrapper.GZIP));
123         p.addLast("gzipinflater", ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP));
124         p.addLast("unificationB", new PortUnificationServerHandler(sslCtx, detectSsl, false));
125         p.remove(this);
126     }
127 
128     private void switchToHttp(ChannelHandlerContext ctx) {
129         ChannelPipeline p = ctx.pipeline();
130         p.addLast("decoder", new HttpRequestDecoder());
131         p.addLast("encoder", new HttpResponseEncoder());
132         p.addLast("deflater", new HttpContentCompressor());
133         p.addLast("handler", new HttpSnoopServerHandler());
134         p.remove(this);
135     }
136 
137     private void switchToFactorial(ChannelHandlerContext ctx) {
138         ChannelPipeline p = ctx.pipeline();
139         p.addLast("decoder", new BigIntegerDecoder());
140         p.addLast("encoder", new NumberEncoder());
141         p.addLast("handler", new FactorialServerHandler());
142         p.remove(this);
143     }
144 }