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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.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.CompressionOptions;
27  import io.netty.handler.codec.compression.ZlibCodecFactory;
28  import io.netty.handler.codec.compression.ZlibWrapper;
29  import io.netty.handler.codec.http.HttpContentCompressor;
30  import io.netty.handler.codec.http.HttpRequestDecoder;
31  import io.netty.handler.codec.http.HttpResponseEncoder;
32  import io.netty.handler.ssl.SslContext;
33  import io.netty.handler.ssl.SslHandler;
34  
35  import java.util.List;
36  
37  /**
38   * Manipulates the current pipeline dynamically to switch protocols or enable
39   * SSL or GZIP.
40   */
41  public class PortUnificationServerHandler extends ByteToMessageDecoder {
42  
43      private final SslContext sslCtx;
44      private final boolean detectSsl;
45      private final boolean detectGzip;
46  
47      public PortUnificationServerHandler(SslContext sslCtx) {
48          this(sslCtx, true, true);
49      }
50  
51      private PortUnificationServerHandler(SslContext sslCtx, boolean detectSsl, boolean detectGzip) {
52          this.sslCtx = sslCtx;
53          this.detectSsl = detectSsl;
54          this.detectGzip = detectGzip;
55      }
56  
57      @Override
58      protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
59          // Will use the first five bytes to detect a protocol.
60          if (in.readableBytes() < 5) {
61              return;
62          }
63  
64          if (isSsl(in)) {
65              enableSsl(ctx);
66          } else {
67              final int magic1 = in.getUnsignedByte(in.readerIndex());
68              final int magic2 = in.getUnsignedByte(in.readerIndex() + 1);
69              if (isGzip(magic1, magic2)) {
70                  enableGzip(ctx);
71              } else if (isHttp(magic1, magic2)) {
72                  switchToHttp(ctx);
73              } else if (isFactorial(magic1)) {
74                  switchToFactorial(ctx);
75              } else {
76                  // Unknown protocol; discard everything and close the connection.
77                  in.clear();
78                  ctx.close();
79              }
80          }
81      }
82  
83      private boolean isSsl(ByteBuf buf) {
84          if (detectSsl) {
85              return SslHandler.isEncrypted(buf, false);
86          }
87          return false;
88      }
89  
90      private boolean isGzip(int magic1, int magic2) {
91          if (detectGzip) {
92              return magic1 == 31 && magic2 == 139;
93          }
94          return false;
95      }
96  
97      private static boolean isHttp(int magic1, int magic2) {
98          return
99              magic1 == 'G' && magic2 == 'E' || // GET
100             magic1 == 'P' && magic2 == 'O' || // POST
101             magic1 == 'P' && magic2 == 'U' || // PUT
102             magic1 == 'H' && magic2 == 'E' || // HEAD
103             magic1 == 'O' && magic2 == 'P' || // OPTIONS
104             magic1 == 'P' && magic2 == 'A' || // PATCH
105             magic1 == 'D' && magic2 == 'E' || // DELETE
106             magic1 == 'T' && magic2 == 'R' || // TRACE
107             magic1 == 'C' && magic2 == 'O';   // CONNECT
108     }
109 
110     private static boolean isFactorial(int magic1) {
111         return magic1 == 'F';
112     }
113 
114     private void enableSsl(ChannelHandlerContext ctx) {
115         ChannelPipeline p = ctx.pipeline();
116         p.addLast("ssl", sslCtx.newHandler(ctx.alloc()));
117         p.addLast("unificationA", new PortUnificationServerHandler(sslCtx, false, detectGzip));
118         p.remove(this);
119     }
120 
121     private void enableGzip(ChannelHandlerContext ctx) {
122         ChannelPipeline p = ctx.pipeline();
123         p.addLast("gzipdeflater", ZlibCodecFactory.newZlibEncoder(ZlibWrapper.GZIP));
124         p.addLast("gzipinflater", ZlibCodecFactory.newZlibDecoder(ZlibWrapper.GZIP));
125         p.addLast("unificationB", new PortUnificationServerHandler(sslCtx, detectSsl, false));
126         p.remove(this);
127     }
128 
129     private void switchToHttp(ChannelHandlerContext ctx) {
130         ChannelPipeline p = ctx.pipeline();
131         p.addLast("decoder", new HttpRequestDecoder());
132         p.addLast("encoder", new HttpResponseEncoder());
133         p.addLast("deflater", new HttpContentCompressor((CompressionOptions[]) null));
134         p.addLast("handler", new HttpSnoopServerHandler());
135         p.remove(this);
136     }
137 
138     private void switchToFactorial(ChannelHandlerContext ctx) {
139         ChannelPipeline p = ctx.pipeline();
140         p.addLast("decoder", new BigIntegerDecoder());
141         p.addLast("encoder", new NumberEncoder());
142         p.addLast("handler", new FactorialServerHandler());
143         p.remove(this);
144     }
145 }