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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  // (BSD License: http://www.opensource.org/licenses/bsd-license)
17  //
18  // Copyright (c) 2011, Joe Walnes and contributors
19  // All rights reserved.
20  //
21  // Redistribution and use in source and binary forms, with or
22  // without modification, are permitted provided that the
23  // following conditions are met:
24  //
25  // * Redistributions of source code must retain the above
26  // copyright notice, this list of conditions and the
27  // following disclaimer.
28  //
29  // * Redistributions in binary form must reproduce the above
30  // copyright notice, this list of conditions and the
31  // following disclaimer in the documentation and/or other
32  // materials provided with the distribution.
33  //
34  // * Neither the name of the Webbit nor the names of
35  // its contributors may be used to endorse or promote products
36  // derived from this software without specific prior written
37  // permission.
38  //
39  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
40  // CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
41  // INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
42  // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
43  // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
44  // CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
45  // INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
46  // (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
47  // GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
48  // BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
49  // LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
50  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51  // OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
52  // POSSIBILITY OF SUCH DAMAGE.
53  
54  package org.jboss.netty.handler.codec.http.websocketx;
55  
56  import org.jboss.netty.buffer.ChannelBuffer;
57  import org.jboss.netty.buffer.ChannelBuffers;
58  import org.jboss.netty.channel.Channel;
59  import org.jboss.netty.channel.ChannelHandlerContext;
60  import org.jboss.netty.handler.codec.frame.TooLongFrameException;
61  import org.jboss.netty.handler.codec.oneone.OneToOneEncoder;
62  import org.jboss.netty.logging.InternalLogger;
63  import org.jboss.netty.logging.InternalLoggerFactory;
64  
65  import java.nio.ByteBuffer;
66  
67  /**
68   * <p>
69   * Encodes a web socket frame into wire protocol version 8 format. This code was forked from <a
70   * href="https://github.com/joewalnes/webbit">webbit</a> and modified.
71   * </p>
72   */
73  public class WebSocket08FrameEncoder extends OneToOneEncoder {
74  
75      private static final InternalLogger logger = InternalLoggerFactory.getInstance(WebSocket08FrameEncoder.class);
76  
77      private static final byte OPCODE_CONT = 0x0;
78      private static final byte OPCODE_TEXT = 0x1;
79      private static final byte OPCODE_BINARY = 0x2;
80      private static final byte OPCODE_CLOSE = 0x8;
81      private static final byte OPCODE_PING = 0x9;
82      private static final byte OPCODE_PONG = 0xA;
83  
84      private final boolean maskPayload;
85  
86      /**
87       * Constructor
88       *
89       * @param maskPayload
90       *            Web socket clients must set this to true to mask payload. Server implementations must set this to
91       *            false.
92       */
93      public WebSocket08FrameEncoder(boolean maskPayload) {
94          this.maskPayload = maskPayload;
95      }
96  
97      @Override
98      protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
99  
100         byte[] mask;
101 
102         if (msg instanceof WebSocketFrame) {
103             WebSocketFrame frame = (WebSocketFrame) msg;
104             ChannelBuffer data = frame.getBinaryData();
105             if (data == null) {
106                 data = ChannelBuffers.EMPTY_BUFFER;
107             }
108 
109             byte opcode;
110             if (frame instanceof TextWebSocketFrame) {
111                 opcode = OPCODE_TEXT;
112             } else if (frame instanceof PingWebSocketFrame) {
113                 opcode = OPCODE_PING;
114             } else if (frame instanceof PongWebSocketFrame) {
115                 opcode = OPCODE_PONG;
116             } else if (frame instanceof CloseWebSocketFrame) {
117                 opcode = OPCODE_CLOSE;
118             } else if (frame instanceof BinaryWebSocketFrame) {
119                 opcode = OPCODE_BINARY;
120             } else if (frame instanceof ContinuationWebSocketFrame) {
121                 opcode = OPCODE_CONT;
122             } else {
123                 throw new UnsupportedOperationException("Cannot encode frame of type: " + frame.getClass().getName());
124             }
125 
126             int length = data.readableBytes();
127 
128             if (logger.isDebugEnabled()) {
129                 logger.debug("Encoding WebSocket Frame opCode=" + opcode + " length=" + length);
130             }
131 
132             int b0 = 0;
133             if (frame.isFinalFragment()) {
134                 b0 |= 1 << 7;
135             }
136             b0 |= frame.getRsv() % 8 << 4;
137             b0 |= opcode % 128;
138 
139             ChannelBuffer header;
140             ChannelBuffer body;
141 
142             if (opcode == OPCODE_PING && length > 125) {
143                 throw new TooLongFrameException("invalid payload for PING (payload length must be <= 125, was "
144                         + length);
145             }
146 
147             int maskLength = maskPayload ? 4 : 0;
148             if (length <= 125) {
149                 header = ChannelBuffers.buffer(2 + maskLength);
150                 header.writeByte(b0);
151                 byte b = (byte) (maskPayload ? 0x80 | (byte) length : (byte) length);
152                 header.writeByte(b);
153             } else if (length <= 0xFFFF) {
154                 header = ChannelBuffers.buffer(4 + maskLength);
155                 header.writeByte(b0);
156                 header.writeByte(maskPayload ? 0xFE : 126);
157                 header.writeByte(length >>> 8 & 0xFF);
158                 header.writeByte(length & 0xFF);
159             } else {
160                 header = ChannelBuffers.buffer(10 + maskLength);
161                 header.writeByte(b0);
162                 header.writeByte(maskPayload ? 0xFF : 127);
163                 header.writeLong(length);
164             }
165 
166             // Write payload
167             if (maskPayload) {
168                 Integer random = (int) (Math.random() * Integer.MAX_VALUE);
169                 mask = ByteBuffer.allocate(4).putInt(random).array();
170                 header.writeBytes(mask);
171 
172                 body = ChannelBuffers.buffer(length);
173                 int counter = 0;
174                 while (data.readableBytes() > 0) {
175                     byte byteData = data.readByte();
176                     body.writeByte(byteData ^ mask[counter++ % 4]);
177                 }
178             } else {
179                 body = data;
180             }
181             return ChannelBuffers.wrappedBuffer(header, body);
182         }
183 
184         // If not websocket, then just return the message
185         return msg;
186     }
187 
188 }