net/quic/quic_packet_generator.cc

   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 #include "net/quic/quic_packet_generator.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/logging.h"
   9 #include "net/quic/quic_fec_group.h"
  10 #include "net/quic/quic_utils.h"
  11
  12 using base::StringPiece;
  13
  14 namespace net {
  15
  16 class QuicAckNotifier;
  17
  18 QuicPacketGenerator::QuicPacketGenerator(DelegateInterface* delegate,
  19                                          DebugDelegateInterface* debug_delegate,
  20                                          QuicPacketCreator* creator)
  21     : delegate_(delegate),
  22       debug_delegate_(debug_delegate),
  23       packet_creator_(creator),
  24       batch_mode_(false),
  25       should_send_ack_(false),
  26       should_send_feedback_(false),
  27       should_send_stop_waiting_(false) {
  28 }
  29
  30 QuicPacketGenerator::~QuicPacketGenerator() {
  31   for (QuicFrames::iterator it = queued_control_frames_.begin();
  32        it != queued_control_frames_.end(); ++it) {
  33     switch (it->type) {
  34       case PADDING_FRAME:
  35         delete it->padding_frame;
  36         break;
  37       case STREAM_FRAME:
  38         delete it->stream_frame;
  39         break;
  40       case ACK_FRAME:
  41         delete it->ack_frame;
  42         break;
  43       case CONGESTION_FEEDBACK_FRAME:
  44         delete it->congestion_feedback_frame;
  45         break;
  46       case RST_STREAM_FRAME:
  47         delete it->rst_stream_frame;
  48         break;
  49       case CONNECTION_CLOSE_FRAME:
  50         delete it->connection_close_frame;
  51         break;
  52       case GOAWAY_FRAME:
  53         delete it->goaway_frame;
  54         break;
  55       case WINDOW_UPDATE_FRAME:
  56         delete it->window_update_frame;
  57         break;
  58       case BLOCKED_FRAME:
  59         delete it->blocked_frame;
  60         break;
  61       case STOP_WAITING_FRAME:
  62         delete it->stop_waiting_frame;
  63         break;
  64       case NUM_FRAME_TYPES:
  65         DCHECK(false) << "Cannot delete type: " << it->type;
  66     }
  67   }
  68 }
  69
  70 void QuicPacketGenerator::SetShouldSendAck(bool also_send_feedback,
  71                                            bool also_send_stop_waiting) {
  72   should_send_ack_ = true;
  73   should_send_feedback_ = also_send_feedback;
  74   should_send_stop_waiting_ = also_send_stop_waiting;
  75   SendQueuedFrames(false);
  76 }
  77
  78 void QuicPacketGenerator::SetShouldSendStopWaiting() {
  79   should_send_stop_waiting_ = true;
  80   SendQueuedFrames(false);
  81 }
  82
  83 void QuicPacketGenerator::AddControlFrame(const QuicFrame& frame) {
  84   queued_control_frames_.push_back(frame);
  85   SendQueuedFrames(false);
  86 }
  87
  88 QuicConsumedData QuicPacketGenerator::ConsumeData(QuicStreamId id,
  89                                                   const IOVector& data_to_write,
  90                                                   QuicStreamOffset offset,
  91                                                   bool fin,
  92                                                   QuicAckNotifier* notifier) {
  93   IsHandshake handshake = id == kCryptoStreamId ? IS_HANDSHAKE : NOT_HANDSHAKE;
  94   // The caller should have flushed pending frames before sending handshake
  95   // messages.
  96   DCHECK(handshake == NOT_HANDSHAKE || !HasPendingFrames());
  97   SendQueuedFrames(false);
  98
  99   size_t total_bytes_consumed = 0;
 100   bool fin_consumed = false;
 101
 102   if (!packet_creator_->HasRoomForStreamFrame(id, offset)) {
 103     SerializeAndSendPacket();
 104   }
 105
 106   IOVector data = data_to_write;
 107   size_t data_size = data.TotalBufferSize();
 108   while (delegate_->ShouldGeneratePacket(NOT_RETRANSMISSION,
 109                                          HAS_RETRANSMITTABLE_DATA, handshake)) {
 110     QuicFrame frame;
 111     size_t bytes_consumed;
 112     if (notifier != NULL) {
 113       // We want to track which packet this stream frame ends up in.
 114       bytes_consumed = packet_creator_->CreateStreamFrameWithNotifier(
 115           id, data, offset + total_bytes_consumed, fin, notifier, &frame);
 116     } else {
 117       bytes_consumed = packet_creator_->CreateStreamFrame(
 118           id, data, offset + total_bytes_consumed, fin, &frame);
 119     }
 120     if (!AddFrame(frame)) {
 121       LOG(DFATAL) << "Failed to add stream frame.";
 122       // Inability to add a STREAM frame creates an unrecoverable hole in a
 123       // the stream, so it's best to close the connection.
 124       delegate_->CloseConnection(QUIC_INTERNAL_ERROR, false);
 125       return QuicConsumedData(0, false);
 126     }
 127
 128     total_bytes_consumed += bytes_consumed;
 129     fin_consumed = fin && total_bytes_consumed == data_size;
 130     data.Consume(bytes_consumed);
 131     DCHECK(data.Empty() || packet_creator_->BytesFree() == 0u);
 132
 133     // TODO(ianswett): Restore packet reordering.
 134     if (!InBatchMode() || !packet_creator_->HasRoomForStreamFrame(id, offset)) {
 135       SerializeAndSendPacket();
 136     }
 137
 138     if (data.Empty()) {
 139       // We're done writing the data. Exit the loop.
 140       // We don't make this a precondition because we could have 0 bytes of data
 141       // if we're simply writing a fin.
 142       break;
 143     }
 144   }
 145
 146   // Ensure the FEC group is closed at the end of this method if not in batch
 147   // mode.
 148   if (!InBatchMode() && packet_creator_->ShouldSendFec(true)) {
 149     SerializedPacket serialized_fec = packet_creator_->SerializeFec();
 150     DCHECK(serialized_fec.packet);
 151     delegate_->OnSerializedPacket(serialized_fec);
 152   }
 153
 154   DCHECK(InBatchMode() || !packet_creator_->HasPendingFrames());
 155   return QuicConsumedData(total_bytes_consumed, fin_consumed);
 156 }
 157
 158 bool QuicPacketGenerator::CanSendWithNextPendingFrameAddition() const {
 159   DCHECK(HasPendingFrames());
 160   HasRetransmittableData retransmittable =
 161       (should_send_ack_ || should_send_feedback_ || should_send_stop_waiting_)
 162       ? NO_RETRANSMITTABLE_DATA : HAS_RETRANSMITTABLE_DATA;
 163   if (retransmittable == HAS_RETRANSMITTABLE_DATA) {
 164       DCHECK(!queued_control_frames_.empty());  // These are retransmittable.
 165   }
 166   return delegate_->ShouldGeneratePacket(NOT_RETRANSMISSION, retransmittable,
 167                                          NOT_HANDSHAKE);
 168 }
 169
 170 void QuicPacketGenerator::SendQueuedFrames(bool flush) {
 171   // Only add pending frames if we are SURE we can then send the whole packet.
 172   while (HasPendingFrames() &&
 173          (flush || CanSendWithNextPendingFrameAddition())) {
 174     if (!AddNextPendingFrame()) {
 175       // Packet was full, so serialize and send it.
 176       SerializeAndSendPacket();
 177     }
 178   }
 179
 180   if (!InBatchMode() || flush) {
 181     if (packet_creator_->HasPendingFrames()) {
 182       SerializeAndSendPacket();
 183     }
 184
 185     // Ensure the FEC group is closed at the end of this method unless other
 186     // writes are pending.
 187     if (packet_creator_->ShouldSendFec(true)) {
 188       SerializedPacket serialized_fec = packet_creator_->SerializeFec();
 189       DCHECK(serialized_fec.packet);
 190       delegate_->OnSerializedPacket(serialized_fec);
 191     }
 192   }
 193 }
 194
 195 bool QuicPacketGenerator::InBatchMode() {
 196   return batch_mode_;
 197 }
 198
 199 void QuicPacketGenerator::StartBatchOperations() {
 200   batch_mode_ = true;
 201 }
 202
 203 void QuicPacketGenerator::FinishBatchOperations() {
 204   batch_mode_ = false;
 205   SendQueuedFrames(false);
 206 }
 207
 208 void QuicPacketGenerator::FlushAllQueuedFrames() {
 209   SendQueuedFrames(true);
 210 }
 211
 212 bool QuicPacketGenerator::HasQueuedFrames() const {
 213   return packet_creator_->HasPendingFrames() || HasPendingFrames();
 214 }
 215
 216 bool QuicPacketGenerator::HasPendingFrames() const {
 217   return should_send_ack_ || should_send_feedback_ ||
 218       should_send_stop_waiting_ || !queued_control_frames_.empty();
 219 }
 220
 221 bool QuicPacketGenerator::AddNextPendingFrame() {
 222   if (should_send_ack_) {
 223     pending_ack_frame_.reset(delegate_->CreateAckFrame());
 224     // If we can't this add the frame now, then we still need to do so later.
 225     should_send_ack_ = !AddFrame(QuicFrame(pending_ack_frame_.get()));
 226     // Return success if we have cleared out this flag (i.e., added the frame).
 227     // If we still need to send, then the frame is full, and we have failed.
 228     return !should_send_ack_;
 229   }
 230
 231   if (should_send_feedback_) {
 232     pending_feedback_frame_.reset(delegate_->CreateFeedbackFrame());
 233     // If we can't this add the frame now, then we still need to do so later.
 234     should_send_feedback_ = !AddFrame(QuicFrame(pending_feedback_frame_.get()));
 235     // Return success if we have cleared out this flag (i.e., added the frame).
 236     // If we still need to send, then the frame is full, and we have failed.
 237     return !should_send_feedback_;
 238   }
 239
 240   if (should_send_stop_waiting_) {
 241     pending_stop_waiting_frame_.reset(delegate_->CreateStopWaitingFrame());
 242     // If we can't this add the frame now, then we still need to do so later.
 243     should_send_stop_waiting_ =
 244         !AddFrame(QuicFrame(pending_stop_waiting_frame_.get()));
 245     // Return success if we have cleared out this flag (i.e., added the frame).
 246     // If we still need to send, then the frame is full, and we have failed.
 247     return !should_send_stop_waiting_;
 248   }
 249
 250   LOG_IF(DFATAL, queued_control_frames_.empty())
 251       << "AddNextPendingFrame called with no queued control frames.";
 252   if (!AddFrame(queued_control_frames_.back())) {
 253     // Packet was full.
 254     return false;
 255   }
 256   queued_control_frames_.pop_back();
 257   return true;
 258 }
 259
 260 bool QuicPacketGenerator::AddFrame(const QuicFrame& frame) {
 261   bool success = packet_creator_->AddSavedFrame(frame);
 262   if (success && debug_delegate_) {
 263     debug_delegate_->OnFrameAddedToPacket(frame);
 264   }
 265   return success;
 266 }
 267
 268 void QuicPacketGenerator::SerializeAndSendPacket() {
 269   SerializedPacket serialized_packet = packet_creator_->SerializePacket();
 270   DCHECK(serialized_packet.packet);
 271   delegate_->OnSerializedPacket(serialized_packet);
 272
 273   if (packet_creator_->ShouldSendFec(false)) {
 274     SerializedPacket serialized_fec = packet_creator_->SerializeFec();
 275     DCHECK(serialized_fec.packet);
 276     delegate_->OnSerializedPacket(serialized_fec);
 277   }
 278 }
 279
 280 }  // namespace net