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.
5 #include "net/quic/quic_stream_sequencer.h"
10 #include "base/logging.h"
11 #include "net/quic/reliable_quic_stream.h"
14 using std::numeric_limits;
18 QuicStreamSequencer::QuicStreamSequencer(ReliableQuicStream* quic_stream)
19 : stream_(quic_stream),
20 num_bytes_consumed_(0),
21 max_frame_memory_(numeric_limits<size_t>::max()),
22 close_offset_(numeric_limits<QuicStreamOffset>::max()) {
25 QuicStreamSequencer::QuicStreamSequencer(size_t max_frame_memory,
26 ReliableQuicStream* quic_stream)
27 : stream_(quic_stream),
28 num_bytes_consumed_(0),
29 max_frame_memory_(max_frame_memory),
30 close_offset_(numeric_limits<QuicStreamOffset>::max()) {
31 if (max_frame_memory < kMaxPacketSize) {
32 LOG(DFATAL) << "Setting max frame memory to " << max_frame_memory
33 << ". Some frames will be impossible to handle.";
37 QuicStreamSequencer::~QuicStreamSequencer() {
40 bool QuicStreamSequencer::WillAcceptStreamFrame(
41 const QuicStreamFrame& frame) const {
42 size_t data_len = frame.data.size();
43 DCHECK_LE(data_len, max_frame_memory_);
45 if (IsDuplicate(frame)) {
48 QuicStreamOffset byte_offset = frame.offset;
49 if (data_len > max_frame_memory_) {
50 // We're never going to buffer this frame and we can't pass it up.
51 // The stream might only consume part of it and we'd need a partial ack.
53 // Ideally this should never happen, as we check that
54 // max_frame_memory_ > kMaxPacketSize and lower levels should reject
55 // frames larger than that.
58 if (byte_offset + data_len - num_bytes_consumed_ > max_frame_memory_) {
59 // We can buffer this but not right now. Toss it.
60 // It might be worth trying an experiment where we try best-effort buffering
66 bool QuicStreamSequencer::OnStreamFrame(const QuicStreamFrame& frame) {
67 if (!WillAcceptStreamFrame(frame)) {
68 // This should not happen, as WillAcceptFrame should be called before
69 // OnStreamFrame. Error handling should be done by the caller.
72 if (IsDuplicate(frame)) {
73 // Silently ignore duplicates.
77 QuicStreamOffset byte_offset = frame.offset;
78 const char* data = frame.data.data();
79 size_t data_len = frame.data.size();
81 if (data_len == 0 && !frame.fin) {
82 // Stream frames must have data or a fin flag.
83 stream_->CloseConnectionWithDetails(QUIC_INVALID_STREAM_FRAME,
84 "Empty stream frame without FIN set.");
89 CloseStreamAtOffset(frame.offset + frame.data.size());
95 if (byte_offset == num_bytes_consumed_) {
96 DVLOG(1) << "Processing byte offset " << byte_offset;
97 size_t bytes_consumed = stream_->ProcessRawData(data, data_len);
98 num_bytes_consumed_ += bytes_consumed;
100 if (MaybeCloseStream()) {
103 if (bytes_consumed > data_len) {
104 stream_->Close(QUIC_ERROR_PROCESSING_STREAM);
106 } else if (bytes_consumed == data_len) {
107 FlushBufferedFrames();
108 return true; // it's safe to ack this frame.
110 // Set ourselves up to buffer what's left
111 data_len -= bytes_consumed;
112 data += bytes_consumed;
113 byte_offset += bytes_consumed;
116 DVLOG(1) << "Buffering packet at offset " << byte_offset;
117 frames_.insert(make_pair(byte_offset, string(data, data_len)));
121 void QuicStreamSequencer::CloseStreamAtOffset(QuicStreamOffset offset) {
122 const QuicStreamOffset kMaxOffset = numeric_limits<QuicStreamOffset>::max();
124 // If we have a scheduled termination or close, any new offset should match
126 if (close_offset_ != kMaxOffset && offset != close_offset_) {
127 stream_->Close(QUIC_MULTIPLE_TERMINATION_OFFSETS);
131 close_offset_ = offset;
136 bool QuicStreamSequencer::MaybeCloseStream() {
137 if (IsHalfClosed()) {
138 DVLOG(1) << "Passing up termination, as we've processed "
139 << num_bytes_consumed_ << " of " << close_offset_
141 // Technically it's an error if num_bytes_consumed isn't exactly
142 // equal, but error handling seems silly at this point.
143 stream_->TerminateFromPeer(true);
149 int QuicStreamSequencer::GetReadableRegions(iovec* iov, size_t iov_len) {
150 FrameMap::iterator it = frames_.begin();
152 QuicStreamOffset offset = num_bytes_consumed_;
153 while (it != frames_.end() && index < iov_len) {
154 if (it->first != offset) return index;
156 iov[index].iov_base = static_cast<void*>(
157 const_cast<char*>(it->second.data()));
158 iov[index].iov_len = it->second.size();
159 offset += it->second.size();
167 int QuicStreamSequencer::Readv(const struct iovec* iov, size_t iov_len) {
168 FrameMap::iterator it = frames_.begin();
169 size_t iov_index = 0;
170 size_t iov_offset = 0;
171 size_t frame_offset = 0;
172 size_t initial_bytes_consumed = num_bytes_consumed_;
174 while (iov_index < iov_len &&
175 it != frames_.end() &&
176 it->first == num_bytes_consumed_) {
177 int bytes_to_read = min(iov[iov_index].iov_len - iov_offset,
178 it->second.size() - frame_offset);
180 char* iov_ptr = static_cast<char*>(iov[iov_index].iov_base) + iov_offset;
182 it->second.data() + frame_offset, bytes_to_read);
183 frame_offset += bytes_to_read;
184 iov_offset += bytes_to_read;
186 if (iov[iov_index].iov_len == iov_offset) {
187 // We've filled this buffer.
191 if (it->second.size() == frame_offset) {
192 // We've copied this whole frame
193 num_bytes_consumed_ += it->second.size();
195 it = frames_.begin();
199 // We've finished copying. If we have a partial frame, update it.
200 if (frame_offset != 0) {
201 frames_.insert(make_pair(it->first + frame_offset,
202 it->second.substr(frame_offset)));
203 frames_.erase(frames_.begin());
204 num_bytes_consumed_ += frame_offset;
206 return num_bytes_consumed_ - initial_bytes_consumed;
209 void QuicStreamSequencer::MarkConsumed(size_t num_bytes_consumed) {
210 size_t end_offset = num_bytes_consumed_ + num_bytes_consumed;
211 while (!frames_.empty() && end_offset != num_bytes_consumed_) {
212 FrameMap::iterator it = frames_.begin();
213 if (it->first != num_bytes_consumed_) {
214 LOG(DFATAL) << "Invalid argument to MarkConsumed. "
215 << " num_bytes_consumed_: " << num_bytes_consumed_
216 << " end_offset: " << end_offset
217 << " offset: " << it->first
218 << " length: " << it->second.length();
219 stream_->Close(QUIC_ERROR_PROCESSING_STREAM);
223 if (it->first + it->second.length() <= end_offset) {
224 num_bytes_consumed_ += it->second.length();
225 // This chunk is entirely consumed.
230 // Partially consume this frame.
231 size_t delta = end_offset - it->first;
232 num_bytes_consumed_ += delta;
233 frames_.insert(make_pair(end_offset, it->second.substr(delta)));
239 bool QuicStreamSequencer::HasBytesToRead() const {
240 FrameMap::const_iterator it = frames_.begin();
242 return it != frames_.end() && it->first == num_bytes_consumed_;
245 bool QuicStreamSequencer::IsHalfClosed() const {
246 return num_bytes_consumed_ >= close_offset_;
249 bool QuicStreamSequencer::IsDuplicate(const QuicStreamFrame& frame) const {
250 // A frame is duplicate if the frame offset is smaller than our bytes consumed
251 // or we have stored the frame in our map.
252 // TODO(pwestin): Is it possible that a new frame contain more data even if
253 // the offset is the same?
254 return frame.offset < num_bytes_consumed_ ||
255 frames_.find(frame.offset) != frames_.end();
258 void QuicStreamSequencer::FlushBufferedFrames() {
259 FrameMap::iterator it = frames_.find(num_bytes_consumed_);
260 while (it != frames_.end()) {
261 DVLOG(1) << "Flushing buffered packet at offset " << it->first;
262 string* data = &it->second;
263 size_t bytes_consumed = stream_->ProcessRawData(data->c_str(),
265 num_bytes_consumed_ += bytes_consumed;
266 if (MaybeCloseStream()) {
269 if (bytes_consumed > data->size()) {
270 stream_->Close(QUIC_ERROR_PROCESSING_STREAM); // Programming error
272 } else if (bytes_consumed == data->size()) {
274 it = frames_.find(num_bytes_consumed_);
276 string new_data = it->second.substr(bytes_consumed);
278 frames_.insert(make_pair(num_bytes_consumed_, new_data));