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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #ifndef NET_WEBSOCKETS_WEBSOCKET_FRAME_H_ | |
6 #define NET_WEBSOCKETS_WEBSOCKET_FRAME_H_ | |
7 | |
8 #include <vector> | |
9 | |
10 #include "base/basictypes.h" | |
11 #include "base/memory/ref_counted.h" | |
12 #include "base/memory/scoped_ptr.h" | |
13 #include "net/base/net_export.h" | |
14 | |
15 namespace net { | |
16 | |
17 class IOBuffer; | |
18 class IOBufferWithSize; | |
19 | |
20 // Represents a WebSocket frame header. | |
21 // | |
22 // Members of this class correspond to each element in WebSocket frame header | |
23 // (see http://tools.ietf.org/html/rfc6455#section-5.2). | |
24 struct NET_EXPORT WebSocketFrameHeader { | |
25 typedef int OpCode; | |
26 | |
27 // Originally these constants were static const int, but to make it possible | |
28 // to use them in a switch statement they were changed to an enum. | |
29 enum OpCodeEnum { | |
30 kOpCodeContinuation = 0x0, | |
31 kOpCodeText = 0x1, | |
32 kOpCodeBinary = 0x2, | |
33 kOpCodeDataUnused = 0x3, | |
34 kOpCodeClose = 0x8, | |
35 kOpCodePing = 0x9, | |
36 kOpCodePong = 0xA, | |
37 kOpCodeControlUnused = 0xB, | |
38 }; | |
39 | |
40 // Return true if |opcode| is one of the data opcodes known to this | |
41 // implementation. | |
42 static bool IsKnownDataOpCode(OpCode opcode) { | |
43 return opcode == kOpCodeContinuation || opcode == kOpCodeText || | |
44 opcode == kOpCodeBinary; | |
45 } | |
46 | |
47 // Return true if |opcode| is one of the control opcodes known to this | |
48 // implementation. | |
49 static bool IsKnownControlOpCode(OpCode opcode) { | |
50 return opcode == kOpCodeClose || opcode == kOpCodePing || | |
51 opcode == kOpCodePong; | |
52 } | |
53 | |
54 // These values must be a compile-time constant. "enum hack" is used here | |
55 // to make MSVC happy. | |
56 enum { | |
57 kBaseHeaderSize = 2, | |
58 kMaximumExtendedLengthSize = 8, | |
59 kMaskingKeyLength = 4 | |
60 }; | |
61 | |
62 // Constructor to avoid a lot of repetitive initialisation. | |
63 explicit WebSocketFrameHeader(OpCode opCode) | |
64 : final(false), | |
65 reserved1(false), | |
66 reserved2(false), | |
67 reserved3(false), | |
68 opcode(opCode), | |
69 masked(false), | |
70 payload_length(0) {} | |
71 | |
72 // Create a clone of this object on the heap. | |
73 scoped_ptr<WebSocketFrameHeader> Clone() const; | |
74 | |
75 // Overwrite this object with the fields from |source|. | |
76 void CopyFrom(const WebSocketFrameHeader& source); | |
77 | |
78 // Members below correspond to each item in WebSocket frame header. | |
79 // See <http://tools.ietf.org/html/rfc6455#section-5.2> for details. | |
80 bool final; | |
81 bool reserved1; | |
82 bool reserved2; | |
83 bool reserved3; | |
84 OpCode opcode; | |
85 bool masked; | |
86 uint64 payload_length; | |
87 | |
88 private: | |
89 DISALLOW_COPY_AND_ASSIGN(WebSocketFrameHeader); | |
90 }; | |
91 | |
92 // Contains an entire WebSocket frame including payload. This is used by APIs | |
93 // that are not concerned about retaining the original frame boundaries (because | |
94 // frames may need to be split in order for the data to fit in memory). | |
95 struct NET_EXPORT_PRIVATE WebSocketFrame { | |
96 // A frame must always have an opcode, so this parameter is compulsory. | |
97 explicit WebSocketFrame(WebSocketFrameHeader::OpCode opcode); | |
98 ~WebSocketFrame(); | |
99 | |
100 // |header| is always present. | |
101 WebSocketFrameHeader header; | |
102 | |
103 // |data| is always unmasked even if the frame is masked. The size of |data| | |
104 // is given by |header.payload_length|. | |
105 scoped_refptr<IOBuffer> data; | |
106 }; | |
107 | |
108 // Structure describing one chunk of a WebSocket frame. | |
109 // | |
110 // The payload of a WebSocket frame may be divided into multiple chunks. | |
111 // You need to look at |final_chunk| member variable to detect the end of a | |
112 // series of chunk objects of a WebSocket frame. | |
113 // | |
114 // Frame dissection is necessary to handle frames that are too large to store in | |
115 // the browser memory without losing information about the frame boundaries. In | |
116 // practice, most code does not need to worry about the original frame | |
117 // boundaries and can use the WebSocketFrame type declared above. | |
118 // | |
119 // Users of this struct should treat WebSocket frames as a data stream; it's | |
120 // important to keep the frame data flowing, especially in the browser process. | |
121 // Users should not let the data stuck somewhere in the pipeline. | |
122 // | |
123 // This struct is used for reading WebSocket frame data (created by | |
124 // WebSocketFrameParser). To construct WebSocket frames, use functions below. | |
125 struct NET_EXPORT WebSocketFrameChunk { | |
126 WebSocketFrameChunk(); | |
127 ~WebSocketFrameChunk(); | |
128 | |
129 // Non-null |header| is provided only if this chunk is the first part of | |
130 // a series of chunks. | |
131 scoped_ptr<WebSocketFrameHeader> header; | |
132 | |
133 // Indicates this part is the last chunk of a frame. | |
134 bool final_chunk; | |
135 | |
136 // |data| is always unmasked even if the frame is masked. |data| might be | |
137 // null in the first chunk. | |
138 scoped_refptr<IOBufferWithSize> data; | |
139 }; | |
140 | |
141 // Contains four-byte data representing "masking key" of WebSocket frames. | |
142 struct WebSocketMaskingKey { | |
143 char key[WebSocketFrameHeader::kMaskingKeyLength]; | |
144 }; | |
145 | |
146 // Returns the size of WebSocket frame header. The size of WebSocket frame | |
147 // header varies from 2 bytes to 14 bytes depending on the payload length | |
148 // and maskedness. | |
149 NET_EXPORT int GetWebSocketFrameHeaderSize(const WebSocketFrameHeader& header); | |
150 | |
151 // Writes wire format of a WebSocket frame header into |output|, and returns | |
152 // the number of bytes written. | |
153 // | |
154 // WebSocket frame format is defined at: | |
155 // <http://tools.ietf.org/html/rfc6455#section-5.2>. This function writes | |
156 // everything but payload data in a WebSocket frame to |buffer|. | |
157 // | |
158 // If |header->masked| is true, |masking_key| must point to a valid | |
159 // WebSocketMaskingKey object containing the masking key for that frame | |
160 // (possibly generated by GenerateWebSocketMaskingKey() function below). | |
161 // Otherwise, |masking_key| must be NULL. | |
162 // | |
163 // |buffer| should have enough size to contain the frame header. | |
164 // GetWebSocketFrameHeaderSize() can be used to know the size of header | |
165 // beforehand. If the size of |buffer| is insufficient, this function returns | |
166 // ERR_INVALID_ARGUMENT and does not write any data to |buffer|. | |
167 NET_EXPORT int WriteWebSocketFrameHeader(const WebSocketFrameHeader& header, | |
168 const WebSocketMaskingKey* masking_key, | |
169 char* buffer, | |
170 int buffer_size); | |
171 | |
172 // Generates a masking key suitable for use in a new WebSocket frame. | |
173 NET_EXPORT WebSocketMaskingKey GenerateWebSocketMaskingKey(); | |
174 | |
175 // Masks WebSocket frame payload. | |
176 // | |
177 // A client must mask every WebSocket frame by XOR'ing the frame payload | |
178 // with four-byte random data (masking key). This function applies the masking | |
179 // to the given payload data. | |
180 // | |
181 // This function masks |data| with |masking_key|, assuming |data| is partial | |
182 // data starting from |frame_offset| bytes from the beginning of the payload | |
183 // data. | |
184 // | |
185 // Since frame masking is a reversible operation, this function can also be | |
186 // used for unmasking a WebSocket frame. | |
187 NET_EXPORT void MaskWebSocketFramePayload( | |
188 const WebSocketMaskingKey& masking_key, | |
189 uint64 frame_offset, | |
190 char* data, | |
191 int data_size); | |
192 | |
193 } // namespace net | |
194 | |
195 #endif // NET_WEBSOCKETS_WEBSOCKET_FRAME_H_ | |
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