net/websockets/websocket_deflate_stream.cc

   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_deflate_stream.h"
   6
   7 #include <algorithm>
   8 #include <string>
   9
  10 #include "base/bind.h"
  11 #include "base/logging.h"
  12 #include "base/memory/ref_counted.h"
  13 #include "base/memory/scoped_ptr.h"
  14 #include "base/memory/scoped_vector.h"
  15 #include "net/base/completion_callback.h"
  16 #include "net/base/io_buffer.h"
  17 #include "net/base/net_errors.h"
  18 #include "net/websockets/websocket_deflate_predictor.h"
  19 #include "net/websockets/websocket_deflater.h"
  20 #include "net/websockets/websocket_errors.h"
  21 #include "net/websockets/websocket_frame.h"
  22 #include "net/websockets/websocket_inflater.h"
  23 #include "net/websockets/websocket_stream.h"
  24
  25 class GURL;
  26
  27 namespace net {
  28
  29 namespace {
  30
  31 const int kWindowBits = 15;
  32 const size_t kChunkSize = 4 * 1024;
  33
  34 }  // namespace
  35
  36 WebSocketDeflateStream::WebSocketDeflateStream(
  37     scoped_ptr<WebSocketStream> stream,
  38     WebSocketDeflater::ContextTakeOverMode mode,
  39     int client_window_bits,
  40     scoped_ptr<WebSocketDeflatePredictor> predictor)
  41     : stream_(stream.Pass()),
  42       deflater_(mode),
  43       inflater_(kChunkSize, kChunkSize),
  44       reading_state_(NOT_READING),
  45       writing_state_(NOT_WRITING),
  46       current_reading_opcode_(WebSocketFrameHeader::kOpCodeText),
  47       current_writing_opcode_(WebSocketFrameHeader::kOpCodeText),
  48       predictor_(predictor.Pass()) {
  49   DCHECK(stream_);
  50   DCHECK_GE(client_window_bits, 8);
  51   DCHECK_LE(client_window_bits, 15);
  52   deflater_.Initialize(client_window_bits);
  53   inflater_.Initialize(kWindowBits);
  54 }
  55
  56 WebSocketDeflateStream::~WebSocketDeflateStream() {}
  57
  58 int WebSocketDeflateStream::ReadFrames(ScopedVector<WebSocketFrame>* frames,
  59                                        const CompletionCallback& callback) {
  60   int result = stream_->ReadFrames(
  61       frames,
  62       base::Bind(&WebSocketDeflateStream::OnReadComplete,
  63                  base::Unretained(this),
  64                  base::Unretained(frames),
  65                  callback));
  66   if (result < 0)
  67     return result;
  68   DCHECK_EQ(OK, result);
  69   DCHECK(!frames->empty());
  70
  71   return InflateAndReadIfNecessary(frames, callback);
  72 }
  73
  74 int WebSocketDeflateStream::WriteFrames(ScopedVector<WebSocketFrame>* frames,
  75                                         const CompletionCallback& callback) {
  76   int result = Deflate(frames);
  77   if (result != OK)
  78     return result;
  79   if (frames->empty())
  80     return OK;
  81   return stream_->WriteFrames(frames, callback);
  82 }
  83
  84 void WebSocketDeflateStream::Close() { stream_->Close(); }
  85
  86 std::string WebSocketDeflateStream::GetSubProtocol() const {
  87   return stream_->GetSubProtocol();
  88 }
  89
  90 std::string WebSocketDeflateStream::GetExtensions() const {
  91   return stream_->GetExtensions();
  92 }
  93
  94 void WebSocketDeflateStream::OnReadComplete(
  95     ScopedVector<WebSocketFrame>* frames,
  96     const CompletionCallback& callback,
  97     int result) {
  98   if (result != OK) {
  99     frames->clear();
 100     callback.Run(result);
 101     return;
 102   }
 103
 104   int r = InflateAndReadIfNecessary(frames, callback);
 105   if (r != ERR_IO_PENDING)
 106     callback.Run(r);
 107 }
 108
 109 int WebSocketDeflateStream::Deflate(ScopedVector<WebSocketFrame>* frames) {
 110   ScopedVector<WebSocketFrame> frames_to_write;
 111   // Store frames of the currently processed message if writing_state_ equals to
 112   // WRITING_POSSIBLY_COMPRESSED_MESSAGE.
 113   ScopedVector<WebSocketFrame> frames_of_message;
 114   for (size_t i = 0; i < frames->size(); ++i) {
 115     DCHECK(!(*frames)[i]->header.reserved1);
 116     if (!WebSocketFrameHeader::IsKnownDataOpCode((*frames)[i]->header.opcode)) {
 117       frames_to_write.push_back((*frames)[i]);
 118       (*frames)[i] = NULL;
 119       continue;
 120     }
 121     if (writing_state_ == NOT_WRITING)
 122       OnMessageStart(*frames, i);
 123
 124     scoped_ptr<WebSocketFrame> frame((*frames)[i]);
 125     (*frames)[i] = NULL;
 126     predictor_->RecordInputDataFrame(frame.get());
 127
 128     if (writing_state_ == WRITING_UNCOMPRESSED_MESSAGE) {
 129       if (frame->header.final)
 130         writing_state_ = NOT_WRITING;
 131       predictor_->RecordWrittenDataFrame(frame.get());
 132       frames_to_write.push_back(frame.release());
 133       current_writing_opcode_ = WebSocketFrameHeader::kOpCodeContinuation;
 134     } else {
 135       if (frame->data.get() &&
 136           !deflater_.AddBytes(
 137               frame->data->data(),
 138               static_cast<size_t>(frame->header.payload_length))) {
 139         DVLOG(1) << "WebSocket protocol error. "
 140                  << "deflater_.AddBytes() returns an error.";
 141         return ERR_WS_PROTOCOL_ERROR;
 142       }
 143       if (frame->header.final && !deflater_.Finish()) {
 144         DVLOG(1) << "WebSocket protocol error. "
 145                  << "deflater_.Finish() returns an error.";
 146         return ERR_WS_PROTOCOL_ERROR;
 147       }
 148
 149       if (writing_state_ == WRITING_COMPRESSED_MESSAGE) {
 150         if (deflater_.CurrentOutputSize() >= kChunkSize ||
 151             frame->header.final) {
 152           int result = AppendCompressedFrame(frame->header, &frames_to_write);
 153           if (result != OK)
 154             return result;
 155         }
 156         if (frame->header.final)
 157           writing_state_ = NOT_WRITING;
 158       } else {
 159         DCHECK_EQ(WRITING_POSSIBLY_COMPRESSED_MESSAGE, writing_state_);
 160         bool final = frame->header.final;
 161         frames_of_message.push_back(frame.release());
 162         if (final) {
 163           int result = AppendPossiblyCompressedMessage(&frames_of_message,
 164                                                        &frames_to_write);
 165           if (result != OK)
 166             return result;
 167           frames_of_message.clear();
 168           writing_state_ = NOT_WRITING;
 169         }
 170       }
 171     }
 172   }
 173   DCHECK_NE(WRITING_POSSIBLY_COMPRESSED_MESSAGE, writing_state_);
 174   frames->swap(frames_to_write);
 175   return OK;
 176 }
 177
 178 void WebSocketDeflateStream::OnMessageStart(
 179     const ScopedVector<WebSocketFrame>& frames, size_t index) {
 180   WebSocketFrame* frame = frames[index];
 181   current_writing_opcode_ = frame->header.opcode;
 182   DCHECK(current_writing_opcode_ == WebSocketFrameHeader::kOpCodeText ||
 183          current_writing_opcode_ == WebSocketFrameHeader::kOpCodeBinary);
 184   WebSocketDeflatePredictor::Result prediction =
 185       predictor_->Predict(frames, index);
 186
 187   switch (prediction) {
 188     case WebSocketDeflatePredictor::DEFLATE:
 189       writing_state_ = WRITING_COMPRESSED_MESSAGE;
 190       return;
 191     case WebSocketDeflatePredictor::DO_NOT_DEFLATE:
 192       writing_state_ = WRITING_UNCOMPRESSED_MESSAGE;
 193       return;
 194     case WebSocketDeflatePredictor::TRY_DEFLATE:
 195       writing_state_ = WRITING_POSSIBLY_COMPRESSED_MESSAGE;
 196       return;
 197   }
 198   NOTREACHED();
 199 }
 200
 201 int WebSocketDeflateStream::AppendCompressedFrame(
 202     const WebSocketFrameHeader& header,
 203     ScopedVector<WebSocketFrame>* frames_to_write) {
 204   const WebSocketFrameHeader::OpCode opcode = current_writing_opcode_;
 205   scoped_refptr<IOBufferWithSize> compressed_payload =
 206       deflater_.GetOutput(deflater_.CurrentOutputSize());
 207   if (!compressed_payload.get()) {
 208     DVLOG(1) << "WebSocket protocol error. "
 209              << "deflater_.GetOutput() returns an error.";
 210     return ERR_WS_PROTOCOL_ERROR;
 211   }
 212   scoped_ptr<WebSocketFrame> compressed(new WebSocketFrame(opcode));
 213   compressed->header.CopyFrom(header);
 214   compressed->header.opcode = opcode;
 215   compressed->header.final = header.final;
 216   compressed->header.reserved1 =
 217       (opcode != WebSocketFrameHeader::kOpCodeContinuation);
 218   compressed->data = compressed_payload;
 219   compressed->header.payload_length = compressed_payload->size();
 220
 221   current_writing_opcode_ = WebSocketFrameHeader::kOpCodeContinuation;
 222   predictor_->RecordWrittenDataFrame(compressed.get());
 223   frames_to_write->push_back(compressed.release());
 224   return OK;
 225 }
 226
 227 int WebSocketDeflateStream::AppendPossiblyCompressedMessage(
 228     ScopedVector<WebSocketFrame>* frames,
 229     ScopedVector<WebSocketFrame>* frames_to_write) {
 230   DCHECK(!frames->empty());
 231
 232   const WebSocketFrameHeader::OpCode opcode = current_writing_opcode_;
 233   scoped_refptr<IOBufferWithSize> compressed_payload =
 234       deflater_.GetOutput(deflater_.CurrentOutputSize());
 235   if (!compressed_payload.get()) {
 236     DVLOG(1) << "WebSocket protocol error. "
 237              << "deflater_.GetOutput() returns an error.";
 238     return ERR_WS_PROTOCOL_ERROR;
 239   }
 240
 241   uint64 original_payload_length = 0;
 242   for (size_t i = 0; i < frames->size(); ++i) {
 243     WebSocketFrame* frame = (*frames)[i];
 244     // Asserts checking that frames represent one whole data message.
 245     DCHECK(WebSocketFrameHeader::IsKnownDataOpCode(frame->header.opcode));
 246     DCHECK_EQ(i == 0,
 247               WebSocketFrameHeader::kOpCodeContinuation !=
 248               frame->header.opcode);
 249     DCHECK_EQ(i == frames->size() - 1, frame->header.final);
 250     original_payload_length += frame->header.payload_length;
 251   }
 252   if (original_payload_length <=
 253       static_cast<uint64>(compressed_payload->size())) {
 254     // Compression is not effective. Use the original frames.
 255     for (size_t i = 0; i < frames->size(); ++i) {
 256       WebSocketFrame* frame = (*frames)[i];
 257       frames_to_write->push_back(frame);
 258       predictor_->RecordWrittenDataFrame(frame);
 259       (*frames)[i] = NULL;
 260     }
 261     frames->weak_clear();
 262     return OK;
 263   }
 264   scoped_ptr<WebSocketFrame> compressed(new WebSocketFrame(opcode));
 265   compressed->header.CopyFrom((*frames)[0]->header);
 266   compressed->header.opcode = opcode;
 267   compressed->header.final = true;
 268   compressed->header.reserved1 = true;
 269   compressed->data = compressed_payload;
 270   compressed->header.payload_length = compressed_payload->size();
 271
 272   predictor_->RecordWrittenDataFrame(compressed.get());
 273   frames_to_write->push_back(compressed.release());
 274   return OK;
 275 }
 276
 277 int WebSocketDeflateStream::Inflate(ScopedVector<WebSocketFrame>* frames) {
 278   ScopedVector<WebSocketFrame> frames_to_output;
 279   ScopedVector<WebSocketFrame> frames_passed;
 280   frames->swap(frames_passed);
 281   for (size_t i = 0; i < frames_passed.size(); ++i) {
 282     scoped_ptr<WebSocketFrame> frame(frames_passed[i]);
 283     frames_passed[i] = NULL;
 284     DVLOG(3) << "Input frame: opcode=" << frame->header.opcode
 285              << " final=" << frame->header.final
 286              << " reserved1=" << frame->header.reserved1
 287              << " payload_length=" << frame->header.payload_length;
 288
 289     if (!WebSocketFrameHeader::IsKnownDataOpCode(frame->header.opcode)) {
 290       frames_to_output.push_back(frame.release());
 291       continue;
 292     }
 293
 294     if (reading_state_ == NOT_READING) {
 295       if (frame->header.reserved1)
 296         reading_state_ = READING_COMPRESSED_MESSAGE;
 297       else
 298         reading_state_ = READING_UNCOMPRESSED_MESSAGE;
 299       current_reading_opcode_ = frame->header.opcode;
 300     } else {
 301       if (frame->header.reserved1) {
 302         DVLOG(1) << "WebSocket protocol error. "
 303                  << "Receiving a non-first frame with RSV1 flag set.";
 304         return ERR_WS_PROTOCOL_ERROR;
 305       }
 306     }
 307
 308     if (reading_state_ == READING_UNCOMPRESSED_MESSAGE) {
 309       if (frame->header.final)
 310         reading_state_ = NOT_READING;
 311       current_reading_opcode_ = WebSocketFrameHeader::kOpCodeContinuation;
 312       frames_to_output.push_back(frame.release());
 313     } else {
 314       DCHECK_EQ(reading_state_, READING_COMPRESSED_MESSAGE);
 315       if (frame->data.get() &&
 316           !inflater_.AddBytes(
 317               frame->data->data(),
 318               static_cast<size_t>(frame->header.payload_length))) {
 319         DVLOG(1) << "WebSocket protocol error. "
 320                  << "inflater_.AddBytes() returns an error.";
 321         return ERR_WS_PROTOCOL_ERROR;
 322       }
 323       if (frame->header.final) {
 324         if (!inflater_.Finish()) {
 325           DVLOG(1) << "WebSocket protocol error. "
 326                    << "inflater_.Finish() returns an error.";
 327           return ERR_WS_PROTOCOL_ERROR;
 328         }
 329       }
 330       // TODO(yhirano): Many frames can be generated by the inflater and
 331       // memory consumption can grow.
 332       // We could avoid it, but avoiding it makes this class much more
 333       // complicated.
 334       while (inflater_.CurrentOutputSize() >= kChunkSize ||
 335              frame->header.final) {
 336         size_t size = std::min(kChunkSize, inflater_.CurrentOutputSize());
 337         scoped_ptr<WebSocketFrame> inflated(
 338             new WebSocketFrame(WebSocketFrameHeader::kOpCodeText));
 339         scoped_refptr<IOBufferWithSize> data = inflater_.GetOutput(size);
 340         bool is_final = !inflater_.CurrentOutputSize() && frame->header.final;
 341         if (!data.get()) {
 342           DVLOG(1) << "WebSocket protocol error. "
 343                    << "inflater_.GetOutput() returns an error.";
 344           return ERR_WS_PROTOCOL_ERROR;
 345         }
 346         inflated->header.CopyFrom(frame->header);
 347         inflated->header.opcode = current_reading_opcode_;
 348         inflated->header.final = is_final;
 349         inflated->header.reserved1 = false;
 350         inflated->data = data;
 351         inflated->header.payload_length = data->size();
 352         DVLOG(3) << "Inflated frame: opcode=" << inflated->header.opcode
 353                  << " final=" << inflated->header.final
 354                  << " reserved1=" << inflated->header.reserved1
 355                  << " payload_length=" << inflated->header.payload_length;
 356         frames_to_output.push_back(inflated.release());
 357         current_reading_opcode_ = WebSocketFrameHeader::kOpCodeContinuation;
 358         if (is_final)
 359           break;
 360       }
 361       if (frame->header.final)
 362         reading_state_ = NOT_READING;
 363     }
 364   }
 365   frames->swap(frames_to_output);
 366   return frames->empty() ? ERR_IO_PENDING : OK;
 367 }
 368
 369 int WebSocketDeflateStream::InflateAndReadIfNecessary(
 370     ScopedVector<WebSocketFrame>* frames,
 371     const CompletionCallback& callback) {
 372   int result = Inflate(frames);
 373   while (result == ERR_IO_PENDING) {
 374     DCHECK(frames->empty());
 375
 376     result = stream_->ReadFrames(
 377         frames,
 378         base::Bind(&WebSocketDeflateStream::OnReadComplete,
 379                    base::Unretained(this),
 380                    base::Unretained(frames),
 381                    callback));
 382     if (result < 0)
 383       break;
 384     DCHECK_EQ(OK, result);
 385     DCHECK(!frames->empty());
 386
 387     result = Inflate(frames);
 388   }
 389   if (result < 0)
 390     frames->clear();
 391   return result;
 392 }
 393
 394 }  // namespace net