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1 // Copyright 2013 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 #include "net/websockets/websocket_basic_stream.h" | |
6 | |
7 #include <algorithm> | |
8 #include <limits> | |
9 #include <string> | |
10 #include <vector> | |
11 | |
12 #include "base/basictypes.h" | |
13 #include "base/bind.h" | |
14 #include "base/logging.h" | |
15 #include "base/numerics/safe_conversions.h" | |
16 #include "net/base/io_buffer.h" | |
17 #include "net/base/net_errors.h" | |
18 #include "net/socket/client_socket_handle.h" | |
19 #include "net/websockets/websocket_errors.h" | |
20 #include "net/websockets/websocket_frame.h" | |
21 #include "net/websockets/websocket_frame_parser.h" | |
22 | |
23 namespace net { | |
24 | |
25 namespace { | |
26 | |
27 // This uses type uint64 to match the definition of | |
28 // WebSocketFrameHeader::payload_length in websocket_frame.h. | |
29 const uint64 kMaxControlFramePayload = 125; | |
30 | |
31 // The number of bytes to attempt to read at a time. | |
32 // TODO(ricea): See if there is a better number or algorithm to fulfill our | |
33 // requirements: | |
34 // 1. We would like to use minimal memory on low-bandwidth or idle connections | |
35 // 2. We would like to read as close to line speed as possible on | |
36 // high-bandwidth connections | |
37 // 3. We can't afford to cause jank on the IO thread by copying large buffers | |
38 // around | |
39 // 4. We would like to hit any sweet-spots that might exist in terms of network | |
40 // packet sizes / encryption block sizes / IPC alignment issues, etc. | |
41 const int kReadBufferSize = 32 * 1024; | |
42 | |
43 typedef ScopedVector<WebSocketFrame>::const_iterator WebSocketFrameIterator; | |
44 | |
45 // Returns the total serialized size of |frames|. This function assumes that | |
46 // |frames| will be serialized with mask field. This function forces the | |
47 // masked bit of the frames on. | |
48 int CalculateSerializedSizeAndTurnOnMaskBit( | |
49 ScopedVector<WebSocketFrame>* frames) { | |
50 const uint64 kMaximumTotalSize = std::numeric_limits<int>::max(); | |
51 | |
52 uint64 total_size = 0; | |
53 for (WebSocketFrameIterator it = frames->begin(); it != frames->end(); ++it) { | |
54 WebSocketFrame* frame = *it; | |
55 // Force the masked bit on. | |
56 frame->header.masked = true; | |
57 // We enforce flow control so the renderer should never be able to force us | |
58 // to cache anywhere near 2GB of frames. | |
59 uint64 frame_size = frame->header.payload_length + | |
60 GetWebSocketFrameHeaderSize(frame->header); | |
61 CHECK_LE(frame_size, kMaximumTotalSize - total_size) | |
62 << "Aborting to prevent overflow"; | |
63 total_size += frame_size; | |
64 } | |
65 return static_cast<int>(total_size); | |
66 } | |
67 | |
68 } // namespace | |
69 | |
70 WebSocketBasicStream::WebSocketBasicStream( | |
71 scoped_ptr<ClientSocketHandle> connection, | |
72 const scoped_refptr<GrowableIOBuffer>& http_read_buffer, | |
73 const std::string& sub_protocol, | |
74 const std::string& extensions) | |
75 : read_buffer_(new IOBufferWithSize(kReadBufferSize)), | |
76 connection_(connection.Pass()), | |
77 http_read_buffer_(http_read_buffer), | |
78 sub_protocol_(sub_protocol), | |
79 extensions_(extensions), | |
80 generate_websocket_masking_key_(&GenerateWebSocketMaskingKey) { | |
81 // http_read_buffer_ should not be set if it contains no data. | |
82 if (http_read_buffer_.get() && http_read_buffer_->offset() == 0) | |
83 http_read_buffer_ = NULL; | |
84 DCHECK(connection_->is_initialized()); | |
85 } | |
86 | |
87 WebSocketBasicStream::~WebSocketBasicStream() { Close(); } | |
88 | |
89 int WebSocketBasicStream::ReadFrames(ScopedVector<WebSocketFrame>* frames, | |
90 const CompletionCallback& callback) { | |
91 DCHECK(frames->empty()); | |
92 // If there is data left over after parsing the HTTP headers, attempt to parse | |
93 // it as WebSocket frames. | |
94 if (http_read_buffer_.get()) { | |
95 DCHECK_GE(http_read_buffer_->offset(), 0); | |
96 // We cannot simply copy the data into read_buffer_, as it might be too | |
97 // large. | |
98 scoped_refptr<GrowableIOBuffer> buffered_data; | |
99 buffered_data.swap(http_read_buffer_); | |
100 DCHECK(http_read_buffer_.get() == NULL); | |
101 ScopedVector<WebSocketFrameChunk> frame_chunks; | |
102 if (!parser_.Decode(buffered_data->StartOfBuffer(), | |
103 buffered_data->offset(), | |
104 &frame_chunks)) | |
105 return WebSocketErrorToNetError(parser_.websocket_error()); | |
106 if (!frame_chunks.empty()) { | |
107 int result = ConvertChunksToFrames(&frame_chunks, frames); | |
108 if (result != ERR_IO_PENDING) | |
109 return result; | |
110 } | |
111 } | |
112 | |
113 // Run until socket stops giving us data or we get some frames. | |
114 while (true) { | |
115 // base::Unretained(this) here is safe because net::Socket guarantees not to | |
116 // call any callbacks after Disconnect(), which we call from the | |
117 // destructor. The caller of ReadFrames() is required to keep |frames| | |
118 // valid. | |
119 int result = connection_->socket()->Read( | |
120 read_buffer_.get(), | |
121 read_buffer_->size(), | |
122 base::Bind(&WebSocketBasicStream::OnReadComplete, | |
123 base::Unretained(this), | |
124 base::Unretained(frames), | |
125 callback)); | |
126 if (result == ERR_IO_PENDING) | |
127 return result; | |
128 result = HandleReadResult(result, frames); | |
129 if (result != ERR_IO_PENDING) | |
130 return result; | |
131 DCHECK(frames->empty()); | |
132 } | |
133 } | |
134 | |
135 int WebSocketBasicStream::WriteFrames(ScopedVector<WebSocketFrame>* frames, | |
136 const CompletionCallback& callback) { | |
137 // This function always concatenates all frames into a single buffer. | |
138 // TODO(ricea): Investigate whether it would be better in some cases to | |
139 // perform multiple writes with smaller buffers. | |
140 // | |
141 // First calculate the size of the buffer we need to allocate. | |
142 int total_size = CalculateSerializedSizeAndTurnOnMaskBit(frames); | |
143 scoped_refptr<IOBufferWithSize> combined_buffer( | |
144 new IOBufferWithSize(total_size)); | |
145 | |
146 char* dest = combined_buffer->data(); | |
147 int remaining_size = total_size; | |
148 for (WebSocketFrameIterator it = frames->begin(); it != frames->end(); ++it) { | |
149 WebSocketFrame* frame = *it; | |
150 WebSocketMaskingKey mask = generate_websocket_masking_key_(); | |
151 int result = | |
152 WriteWebSocketFrameHeader(frame->header, &mask, dest, remaining_size); | |
153 DCHECK_NE(ERR_INVALID_ARGUMENT, result) | |
154 << "WriteWebSocketFrameHeader() says that " << remaining_size | |
155 << " is not enough to write the header in. This should not happen."; | |
156 CHECK_GE(result, 0) << "Potentially security-critical check failed"; | |
157 dest += result; | |
158 remaining_size -= result; | |
159 | |
160 CHECK_LE(frame->header.payload_length, static_cast<uint64>(remaining_size)); | |
161 const int frame_size = static_cast<int>(frame->header.payload_length); | |
162 if (frame_size > 0) { | |
163 const char* const frame_data = frame->data->data(); | |
164 std::copy(frame_data, frame_data + frame_size, dest); | |
165 MaskWebSocketFramePayload(mask, 0, dest, frame_size); | |
166 dest += frame_size; | |
167 remaining_size -= frame_size; | |
168 } | |
169 } | |
170 DCHECK_EQ(0, remaining_size) << "Buffer size calculation was wrong; " | |
171 << remaining_size << " bytes left over."; | |
172 scoped_refptr<DrainableIOBuffer> drainable_buffer( | |
173 new DrainableIOBuffer(combined_buffer.get(), total_size)); | |
174 return WriteEverything(drainable_buffer, callback); | |
175 } | |
176 | |
177 void WebSocketBasicStream::Close() { connection_->socket()->Disconnect(); } | |
178 | |
179 std::string WebSocketBasicStream::GetSubProtocol() const { | |
180 return sub_protocol_; | |
181 } | |
182 | |
183 std::string WebSocketBasicStream::GetExtensions() const { return extensions_; } | |
184 | |
185 /*static*/ | |
186 scoped_ptr<WebSocketBasicStream> | |
187 WebSocketBasicStream::CreateWebSocketBasicStreamForTesting( | |
188 scoped_ptr<ClientSocketHandle> connection, | |
189 const scoped_refptr<GrowableIOBuffer>& http_read_buffer, | |
190 const std::string& sub_protocol, | |
191 const std::string& extensions, | |
192 WebSocketMaskingKeyGeneratorFunction key_generator_function) { | |
193 scoped_ptr<WebSocketBasicStream> stream(new WebSocketBasicStream( | |
194 connection.Pass(), http_read_buffer, sub_protocol, extensions)); | |
195 stream->generate_websocket_masking_key_ = key_generator_function; | |
196 return stream.Pass(); | |
197 } | |
198 | |
199 int WebSocketBasicStream::WriteEverything( | |
200 const scoped_refptr<DrainableIOBuffer>& buffer, | |
201 const CompletionCallback& callback) { | |
202 while (buffer->BytesRemaining() > 0) { | |
203 // The use of base::Unretained() here is safe because on destruction we | |
204 // disconnect the socket, preventing any further callbacks. | |
205 int result = connection_->socket()->Write( | |
206 buffer.get(), | |
207 buffer->BytesRemaining(), | |
208 base::Bind(&WebSocketBasicStream::OnWriteComplete, | |
209 base::Unretained(this), | |
210 buffer, | |
211 callback)); | |
212 if (result > 0) { | |
213 buffer->DidConsume(result); | |
214 } else { | |
215 return result; | |
216 } | |
217 } | |
218 return OK; | |
219 } | |
220 | |
221 void WebSocketBasicStream::OnWriteComplete( | |
222 const scoped_refptr<DrainableIOBuffer>& buffer, | |
223 const CompletionCallback& callback, | |
224 int result) { | |
225 if (result < 0) { | |
226 DCHECK_NE(ERR_IO_PENDING, result); | |
227 callback.Run(result); | |
228 return; | |
229 } | |
230 | |
231 DCHECK_NE(0, result); | |
232 buffer->DidConsume(result); | |
233 result = WriteEverything(buffer, callback); | |
234 if (result != ERR_IO_PENDING) | |
235 callback.Run(result); | |
236 } | |
237 | |
238 int WebSocketBasicStream::HandleReadResult( | |
239 int result, | |
240 ScopedVector<WebSocketFrame>* frames) { | |
241 DCHECK_NE(ERR_IO_PENDING, result); | |
242 DCHECK(frames->empty()); | |
243 if (result < 0) | |
244 return result; | |
245 if (result == 0) | |
246 return ERR_CONNECTION_CLOSED; | |
247 ScopedVector<WebSocketFrameChunk> frame_chunks; | |
248 if (!parser_.Decode(read_buffer_->data(), result, &frame_chunks)) | |
249 return WebSocketErrorToNetError(parser_.websocket_error()); | |
250 if (frame_chunks.empty()) | |
251 return ERR_IO_PENDING; | |
252 return ConvertChunksToFrames(&frame_chunks, frames); | |
253 } | |
254 | |
255 int WebSocketBasicStream::ConvertChunksToFrames( | |
256 ScopedVector<WebSocketFrameChunk>* frame_chunks, | |
257 ScopedVector<WebSocketFrame>* frames) { | |
258 for (size_t i = 0; i < frame_chunks->size(); ++i) { | |
259 scoped_ptr<WebSocketFrame> frame; | |
260 int result = ConvertChunkToFrame( | |
261 scoped_ptr<WebSocketFrameChunk>((*frame_chunks)[i]), &frame); | |
262 (*frame_chunks)[i] = NULL; | |
263 if (result != OK) | |
264 return result; | |
265 if (frame) | |
266 frames->push_back(frame.release()); | |
267 } | |
268 // All the elements of |frame_chunks| are now NULL, so there is no point in | |
269 // calling delete on them all. | |
270 frame_chunks->weak_clear(); | |
271 if (frames->empty()) | |
272 return ERR_IO_PENDING; | |
273 return OK; | |
274 } | |
275 | |
276 int WebSocketBasicStream::ConvertChunkToFrame( | |
277 scoped_ptr<WebSocketFrameChunk> chunk, | |
278 scoped_ptr<WebSocketFrame>* frame) { | |
279 DCHECK(frame->get() == NULL); | |
280 bool is_first_chunk = false; | |
281 if (chunk->header) { | |
282 DCHECK(current_frame_header_ == NULL) | |
283 << "Received the header for a new frame without notification that " | |
284 << "the previous frame was complete (bug in WebSocketFrameParser?)"; | |
285 is_first_chunk = true; | |
286 current_frame_header_.swap(chunk->header); | |
287 } | |
288 const int chunk_size = chunk->data.get() ? chunk->data->size() : 0; | |
289 DCHECK(current_frame_header_) << "Unexpected header-less chunk received " | |
290 << "(final_chunk = " << chunk->final_chunk | |
291 << ", data size = " << chunk_size | |
292 << ") (bug in WebSocketFrameParser?)"; | |
293 scoped_refptr<IOBufferWithSize> data_buffer; | |
294 data_buffer.swap(chunk->data); | |
295 const bool is_final_chunk = chunk->final_chunk; | |
296 const WebSocketFrameHeader::OpCode opcode = current_frame_header_->opcode; | |
297 if (WebSocketFrameHeader::IsKnownControlOpCode(opcode)) { | |
298 bool protocol_error = false; | |
299 if (!current_frame_header_->final) { | |
300 DVLOG(1) << "WebSocket protocol error. Control frame, opcode=" << opcode | |
301 << " received with FIN bit unset."; | |
302 protocol_error = true; | |
303 } | |
304 if (current_frame_header_->payload_length > kMaxControlFramePayload) { | |
305 DVLOG(1) << "WebSocket protocol error. Control frame, opcode=" << opcode | |
306 << ", payload_length=" << current_frame_header_->payload_length | |
307 << " exceeds maximum payload length for a control message."; | |
308 protocol_error = true; | |
309 } | |
310 if (protocol_error) { | |
311 current_frame_header_.reset(); | |
312 return ERR_WS_PROTOCOL_ERROR; | |
313 } | |
314 if (!is_final_chunk) { | |
315 DVLOG(2) << "Encountered a split control frame, opcode " << opcode; | |
316 if (incomplete_control_frame_body_.get()) { | |
317 DVLOG(3) << "Appending to an existing split control frame."; | |
318 AddToIncompleteControlFrameBody(data_buffer); | |
319 } else { | |
320 DVLOG(3) << "Creating new storage for an incomplete control frame."; | |
321 incomplete_control_frame_body_ = new GrowableIOBuffer(); | |
322 // This method checks for oversize control frames above, so as long as | |
323 // the frame parser is working correctly, this won't overflow. If a bug | |
324 // does cause it to overflow, it will CHECK() in | |
325 // AddToIncompleteControlFrameBody() without writing outside the buffer. | |
326 incomplete_control_frame_body_->SetCapacity(kMaxControlFramePayload); | |
327 AddToIncompleteControlFrameBody(data_buffer); | |
328 } | |
329 return OK; | |
330 } | |
331 if (incomplete_control_frame_body_.get()) { | |
332 DVLOG(2) << "Rejoining a split control frame, opcode " << opcode; | |
333 AddToIncompleteControlFrameBody(data_buffer); | |
334 const int body_size = incomplete_control_frame_body_->offset(); | |
335 DCHECK_EQ(body_size, | |
336 static_cast<int>(current_frame_header_->payload_length)); | |
337 scoped_refptr<IOBufferWithSize> body = new IOBufferWithSize(body_size); | |
338 memcpy(body->data(), | |
339 incomplete_control_frame_body_->StartOfBuffer(), | |
340 body_size); | |
341 incomplete_control_frame_body_ = NULL; // Frame now complete. | |
342 DCHECK(is_final_chunk); | |
343 *frame = CreateFrame(is_final_chunk, body); | |
344 return OK; | |
345 } | |
346 } | |
347 | |
348 // Apply basic sanity checks to the |payload_length| field from the frame | |
349 // header. A check for exact equality can only be used when the whole frame | |
350 // arrives in one chunk. | |
351 DCHECK_GE(current_frame_header_->payload_length, | |
352 base::checked_cast<uint64>(chunk_size)); | |
353 DCHECK(!is_first_chunk || !is_final_chunk || | |
354 current_frame_header_->payload_length == | |
355 base::checked_cast<uint64>(chunk_size)); | |
356 | |
357 // Convert the chunk to a complete frame. | |
358 *frame = CreateFrame(is_final_chunk, data_buffer); | |
359 return OK; | |
360 } | |
361 | |
362 scoped_ptr<WebSocketFrame> WebSocketBasicStream::CreateFrame( | |
363 bool is_final_chunk, | |
364 const scoped_refptr<IOBufferWithSize>& data) { | |
365 scoped_ptr<WebSocketFrame> result_frame; | |
366 const bool is_final_chunk_in_message = | |
367 is_final_chunk && current_frame_header_->final; | |
368 const int data_size = data.get() ? data->size() : 0; | |
369 const WebSocketFrameHeader::OpCode opcode = current_frame_header_->opcode; | |
370 // Empty frames convey no useful information unless they are the first frame | |
371 // (containing the type and flags) or have the "final" bit set. | |
372 if (is_final_chunk_in_message || data_size > 0 || | |
373 current_frame_header_->opcode != | |
374 WebSocketFrameHeader::kOpCodeContinuation) { | |
375 result_frame.reset(new WebSocketFrame(opcode)); | |
376 result_frame->header.CopyFrom(*current_frame_header_); | |
377 result_frame->header.final = is_final_chunk_in_message; | |
378 result_frame->header.payload_length = data_size; | |
379 result_frame->data = data; | |
380 // Ensure that opcodes Text and Binary are only used for the first frame in | |
381 // the message. Also clear the reserved bits. | |
382 // TODO(ricea): If a future extension requires the reserved bits to be | |
383 // retained on continuation frames, make this behaviour conditional on a | |
384 // flag set at construction time. | |
385 if (!is_final_chunk && WebSocketFrameHeader::IsKnownDataOpCode(opcode)) { | |
386 current_frame_header_->opcode = WebSocketFrameHeader::kOpCodeContinuation; | |
387 current_frame_header_->reserved1 = false; | |
388 current_frame_header_->reserved2 = false; | |
389 current_frame_header_->reserved3 = false; | |
390 } | |
391 } | |
392 // Make sure that a frame header is not applied to any chunks that do not | |
393 // belong to it. | |
394 if (is_final_chunk) | |
395 current_frame_header_.reset(); | |
396 return result_frame.Pass(); | |
397 } | |
398 | |
399 void WebSocketBasicStream::AddToIncompleteControlFrameBody( | |
400 const scoped_refptr<IOBufferWithSize>& data_buffer) { | |
401 if (!data_buffer.get()) | |
402 return; | |
403 const int new_offset = | |
404 incomplete_control_frame_body_->offset() + data_buffer->size(); | |
405 CHECK_GE(incomplete_control_frame_body_->capacity(), new_offset) | |
406 << "Control frame body larger than frame header indicates; frame parser " | |
407 "bug?"; | |
408 memcpy(incomplete_control_frame_body_->data(), | |
409 data_buffer->data(), | |
410 data_buffer->size()); | |
411 incomplete_control_frame_body_->set_offset(new_offset); | |
412 } | |
413 | |
414 void WebSocketBasicStream::OnReadComplete(ScopedVector<WebSocketFrame>* frames, | |
415 const CompletionCallback& callback, | |
416 int result) { | |
417 result = HandleReadResult(result, frames); | |
418 if (result == ERR_IO_PENDING) | |
419 result = ReadFrames(frames, callback); | |
420 if (result != ERR_IO_PENDING) | |
421 callback.Run(result); | |
422 } | |
423 | |
424 } // namespace net | |
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