| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/quic/quic_packet_generator.h" |
| |
| #include "base/basictypes.h" |
| #include "base/logging.h" |
| #include "net/quic/quic_ack_notifier.h" |
| #include "net/quic/quic_fec_group.h" |
| #include "net/quic/quic_flags.h" |
| #include "net/quic/quic_utils.h" |
| |
| using base::StringPiece; |
| |
| namespace net { |
| |
| namespace { |
| |
| // We want to put some space between a protected packet and the FEC packet to |
| // avoid losing them both within the same loss episode. On the other hand, we |
| // expect to be able to recover from any loss in about an RTT. We resolve this |
| // tradeoff by sending an FEC packet atmost half an RTT, or equivalently, half |
| // the max number of in-flight packets, the first protected packet. Since we |
| // don't want to delay an FEC packet past half an RTT, we set the max FEC group |
| // size to be half the current congestion window. |
| const float kMaxPacketsInFlightMultiplierForFecGroupSize = 0.5; |
| const float kRttMultiplierForFecTimeout = 0.5; |
| |
| // Minimum timeout for FEC alarm, set to half the minimum Tail Loss Probe |
| // timeout of 10ms. |
| const int64 kMinFecTimeoutMs = 5u; |
| |
| } // namespace |
| |
| class QuicAckNotifier; |
| |
| QuicPacketGenerator::QuicPacketGenerator(QuicConnectionId connection_id, |
| QuicFramer* framer, |
| QuicRandom* random_generator, |
| DelegateInterface* delegate) |
| : delegate_(delegate), |
| debug_delegate_(nullptr), |
| packet_creator_(connection_id, framer, random_generator), |
| batch_mode_(false), |
| fec_timeout_(QuicTime::Delta::Zero()), |
| should_fec_protect_(false), |
| should_send_ack_(false), |
| should_send_stop_waiting_(false), |
| ack_queued_(false), |
| stop_waiting_queued_(false) { |
| } |
| |
| QuicPacketGenerator::~QuicPacketGenerator() { |
| for (QuicFrames::iterator it = queued_control_frames_.begin(); |
| it != queued_control_frames_.end(); ++it) { |
| switch (it->type) { |
| case PADDING_FRAME: |
| delete it->padding_frame; |
| break; |
| case STREAM_FRAME: |
| delete it->stream_frame; |
| break; |
| case ACK_FRAME: |
| delete it->ack_frame; |
| break; |
| case RST_STREAM_FRAME: |
| delete it->rst_stream_frame; |
| break; |
| case CONNECTION_CLOSE_FRAME: |
| delete it->connection_close_frame; |
| break; |
| case GOAWAY_FRAME: |
| delete it->goaway_frame; |
| break; |
| case WINDOW_UPDATE_FRAME: |
| delete it->window_update_frame; |
| break; |
| case BLOCKED_FRAME: |
| delete it->blocked_frame; |
| break; |
| case STOP_WAITING_FRAME: |
| delete it->stop_waiting_frame; |
| break; |
| case PING_FRAME: |
| delete it->ping_frame; |
| break; |
| case NUM_FRAME_TYPES: |
| DCHECK(false) << "Cannot delete type: " << it->type; |
| } |
| } |
| } |
| |
| void QuicPacketGenerator::OnCongestionWindowChange( |
| QuicPacketCount max_packets_in_flight) { |
| packet_creator_.set_max_packets_per_fec_group( |
| static_cast<size_t>(kMaxPacketsInFlightMultiplierForFecGroupSize * |
| max_packets_in_flight)); |
| } |
| |
| void QuicPacketGenerator::OnRttChange(QuicTime::Delta rtt) { |
| fec_timeout_ = rtt.Multiply(kRttMultiplierForFecTimeout); |
| } |
| |
| void QuicPacketGenerator::SetShouldSendAck(bool also_send_stop_waiting) { |
| if (ack_queued_) { |
| // Ack already queued, nothing to do. |
| return; |
| } |
| |
| if (also_send_stop_waiting && stop_waiting_queued_) { |
| LOG(DFATAL) << "Should only ever be one pending stop waiting frame."; |
| return; |
| } |
| |
| should_send_ack_ = true; |
| should_send_stop_waiting_ = also_send_stop_waiting; |
| SendQueuedFrames(false); |
| } |
| |
| void QuicPacketGenerator::AddControlFrame(const QuicFrame& frame) { |
| queued_control_frames_.push_back(frame); |
| SendQueuedFrames(false); |
| } |
| |
| QuicConsumedData QuicPacketGenerator::ConsumeData( |
| QuicStreamId id, |
| const IOVector& data_to_write, |
| QuicStreamOffset offset, |
| bool fin, |
| FecProtection fec_protection, |
| QuicAckNotifier::DelegateInterface* delegate) { |
| bool has_handshake = id == kCryptoStreamId; |
| // To make reasoning about crypto frames easier, we don't combine them with |
| // other retransmittable frames in a single packet. |
| const bool flush = |
| has_handshake && packet_creator_.HasPendingRetransmittableFrames(); |
| SendQueuedFrames(flush); |
| |
| size_t total_bytes_consumed = 0; |
| bool fin_consumed = false; |
| |
| if (!packet_creator_.HasRoomForStreamFrame(id, offset)) { |
| SerializeAndSendPacket(); |
| } |
| |
| if (fec_protection == MUST_FEC_PROTECT) { |
| MaybeStartFecProtection(); |
| } |
| |
| // This notifier will be owned by the AckNotifierManager (or deleted below) if |
| // not attached to a packet. |
| QuicAckNotifier* notifier = nullptr; |
| if (delegate != nullptr) { |
| notifier = new QuicAckNotifier(delegate); |
| } |
| |
| IOVector data = data_to_write; |
| size_t data_size = data.TotalBufferSize(); |
| if (!fin && (data_size == 0)) { |
| LOG(DFATAL) << "Attempt to consume empty data without FIN."; |
| return QuicConsumedData(0, false); |
| } |
| |
| int frames_created = 0; |
| while (delegate_->ShouldGeneratePacket( |
| NOT_RETRANSMISSION, HAS_RETRANSMITTABLE_DATA, |
| has_handshake ? IS_HANDSHAKE : NOT_HANDSHAKE)) { |
| QuicFrame frame; |
| size_t bytes_consumed = packet_creator_.CreateStreamFrame( |
| id, data, offset + total_bytes_consumed, fin, &frame); |
| ++frames_created; |
| |
| // We want to track which packet this stream frame ends up in. |
| if (notifier != nullptr) { |
| ack_notifiers_.push_back(notifier); |
| } |
| |
| if (!AddFrame(frame)) { |
| LOG(DFATAL) << "Failed to add stream frame."; |
| // Inability to add a STREAM frame creates an unrecoverable hole in a |
| // the stream, so it's best to close the connection. |
| delegate_->CloseConnection(QUIC_INTERNAL_ERROR, false); |
| delete notifier; |
| return QuicConsumedData(0, false); |
| } |
| |
| total_bytes_consumed += bytes_consumed; |
| fin_consumed = fin && total_bytes_consumed == data_size; |
| data.Consume(bytes_consumed); |
| DCHECK(data.Empty() || packet_creator_.BytesFree() == 0u); |
| |
| // TODO(ianswett): Restore packet reordering. |
| if (!InBatchMode() || !packet_creator_.HasRoomForStreamFrame(id, offset)) { |
| SerializeAndSendPacket(); |
| } |
| |
| if (data.Empty()) { |
| // We're done writing the data. Exit the loop. |
| // We don't make this a precondition because we could have 0 bytes of data |
| // if we're simply writing a fin. |
| if (fec_protection == MUST_FEC_PROTECT) { |
| // Turn off FEC protection when we're done writing protected data. |
| DVLOG(1) << "Turning FEC protection OFF"; |
| should_fec_protect_ = false; |
| } |
| break; |
| } |
| } |
| |
| if (notifier != nullptr && frames_created == 0) { |
| // Safe to delete the AckNotifer as it was never attached to a packet. |
| delete notifier; |
| } |
| |
| // Don't allow the handshake to be bundled with other retransmittable frames. |
| if (has_handshake) { |
| SendQueuedFrames(true); |
| } |
| |
| // Try to close FEC group since we've either run out of data to send or we're |
| // blocked. If not in batch mode, force close the group. |
| MaybeSendFecPacketAndCloseGroup(/*force=*/false); |
| |
| DCHECK(InBatchMode() || !packet_creator_.HasPendingFrames()); |
| return QuicConsumedData(total_bytes_consumed, fin_consumed); |
| } |
| |
| bool QuicPacketGenerator::CanSendWithNextPendingFrameAddition() const { |
| DCHECK(HasPendingFrames()); |
| HasRetransmittableData retransmittable = |
| (should_send_ack_ || should_send_stop_waiting_) |
| ? NO_RETRANSMITTABLE_DATA |
| : HAS_RETRANSMITTABLE_DATA; |
| if (retransmittable == HAS_RETRANSMITTABLE_DATA) { |
| DCHECK(!queued_control_frames_.empty()); // These are retransmittable. |
| } |
| return delegate_->ShouldGeneratePacket(NOT_RETRANSMISSION, retransmittable, |
| NOT_HANDSHAKE); |
| } |
| |
| void QuicPacketGenerator::SendQueuedFrames(bool flush) { |
| // Only add pending frames if we are SURE we can then send the whole packet. |
| while (HasPendingFrames() && |
| (flush || CanSendWithNextPendingFrameAddition())) { |
| if (!AddNextPendingFrame()) { |
| // Packet was full, so serialize and send it. |
| SerializeAndSendPacket(); |
| } |
| } |
| if (packet_creator_.HasPendingFrames() && (flush || !InBatchMode())) { |
| SerializeAndSendPacket(); |
| } |
| MaybeSendFecPacketAndCloseGroup(flush); |
| } |
| |
| void QuicPacketGenerator::MaybeStartFecProtection() { |
| if (!packet_creator_.IsFecEnabled()) { |
| return; |
| } |
| DVLOG(1) << "Turning FEC protection ON"; |
| should_fec_protect_ = true; |
| if (packet_creator_.IsFecProtected()) { |
| // Only start creator's FEC protection if not already on. |
| return; |
| } |
| if (HasQueuedFrames()) { |
| // TODO(jri): This currently requires that the generator flush out any |
| // pending frames when FEC protection is turned on. If current packet can be |
| // converted to an FEC protected packet, do it. This will require the |
| // generator to check if the resulting expansion still allows the incoming |
| // frame to be added to the packet. |
| SendQueuedFrames(true); |
| } |
| packet_creator_.StartFecProtectingPackets(); |
| DCHECK(packet_creator_.IsFecProtected()); |
| } |
| |
| void QuicPacketGenerator::MaybeSendFecPacketAndCloseGroup(bool force) { |
| if (!ShouldSendFecPacket(force)) { |
| return; |
| } |
| // TODO(jri): SerializeFec can return a NULL packet, and this should |
| // cause an early return, with a call to delegate_->OnPacketGenerationError. |
| SerializedPacket serialized_fec = packet_creator_.SerializeFec(); |
| DCHECK(serialized_fec.packet); |
| delegate_->OnSerializedPacket(serialized_fec); |
| // Turn FEC protection off if creator's protection is on and the creator |
| // does not have an open FEC group. |
| // Note: We only wait until the frames queued in the creator are flushed; |
| // pending frames in the generator will not keep us from turning FEC off. |
| if (!should_fec_protect_ && !packet_creator_.IsFecGroupOpen()) { |
| packet_creator_.StopFecProtectingPackets(); |
| DCHECK(!packet_creator_.IsFecProtected()); |
| } |
| } |
| |
| bool QuicPacketGenerator::ShouldSendFecPacket(bool force) { |
| return packet_creator_.IsFecProtected() && |
| !packet_creator_.HasPendingFrames() && |
| packet_creator_.ShouldSendFec(force); |
| } |
| |
| void QuicPacketGenerator::OnFecTimeout() { |
| DCHECK(!InBatchMode()); |
| if (!ShouldSendFecPacket(true)) { |
| LOG(DFATAL) << "No FEC packet to send on FEC timeout."; |
| return; |
| } |
| // Flush out any pending frames in the generator and the creator, and then |
| // send out FEC packet. |
| SendQueuedFrames(true); |
| MaybeSendFecPacketAndCloseGroup(/*force=*/true); |
| } |
| |
| QuicTime::Delta QuicPacketGenerator::GetFecTimeout( |
| QuicPacketSequenceNumber sequence_number) { |
| // Do not set up FEC alarm for |sequence_number| it is not the first packet in |
| // the current group. |
| if (packet_creator_.IsFecGroupOpen() && |
| (sequence_number == packet_creator_.fec_group_number())) { |
| return QuicTime::Delta::Max( |
| fec_timeout_, QuicTime::Delta::FromMilliseconds(kMinFecTimeoutMs)); |
| } |
| return QuicTime::Delta::Infinite(); |
| } |
| |
| bool QuicPacketGenerator::InBatchMode() { |
| return batch_mode_; |
| } |
| |
| void QuicPacketGenerator::StartBatchOperations() { |
| batch_mode_ = true; |
| } |
| |
| void QuicPacketGenerator::FinishBatchOperations() { |
| batch_mode_ = false; |
| SendQueuedFrames(false); |
| } |
| |
| void QuicPacketGenerator::FlushAllQueuedFrames() { |
| SendQueuedFrames(true); |
| } |
| |
| bool QuicPacketGenerator::HasQueuedFrames() const { |
| return packet_creator_.HasPendingFrames() || HasPendingFrames(); |
| } |
| |
| bool QuicPacketGenerator::HasPendingFrames() const { |
| return should_send_ack_ || should_send_stop_waiting_ || |
| !queued_control_frames_.empty(); |
| } |
| |
| bool QuicPacketGenerator::AddNextPendingFrame() { |
| if (should_send_ack_) { |
| delegate_->PopulateAckFrame(&pending_ack_frame_); |
| ack_queued_ = true; |
| // If we can't this add the frame now, then we still need to do so later. |
| should_send_ack_ = !AddFrame(QuicFrame(&pending_ack_frame_)); |
| // Return success if we have cleared out this flag (i.e., added the frame). |
| // If we still need to send, then the frame is full, and we have failed. |
| return !should_send_ack_; |
| } |
| |
| if (should_send_stop_waiting_) { |
| delegate_->PopulateStopWaitingFrame(&pending_stop_waiting_frame_); |
| stop_waiting_queued_ = true; |
| // If we can't this add the frame now, then we still need to do so later. |
| should_send_stop_waiting_ = |
| !AddFrame(QuicFrame(&pending_stop_waiting_frame_)); |
| // Return success if we have cleared out this flag (i.e., added the frame). |
| // If we still need to send, then the frame is full, and we have failed. |
| return !should_send_stop_waiting_; |
| } |
| |
| LOG_IF(DFATAL, queued_control_frames_.empty()) |
| << "AddNextPendingFrame called with no queued control frames."; |
| if (!AddFrame(queued_control_frames_.back())) { |
| // Packet was full. |
| return false; |
| } |
| queued_control_frames_.pop_back(); |
| return true; |
| } |
| |
| bool QuicPacketGenerator::AddFrame(const QuicFrame& frame) { |
| bool success = packet_creator_.AddSavedFrame(frame); |
| if (success && debug_delegate_) { |
| debug_delegate_->OnFrameAddedToPacket(frame); |
| } |
| return success; |
| } |
| |
| void QuicPacketGenerator::SerializeAndSendPacket() { |
| SerializedPacket serialized_packet = packet_creator_.SerializePacket(); |
| DCHECK(serialized_packet.packet); |
| |
| // There may be AckNotifiers interested in this packet. |
| serialized_packet.notifiers.swap(ack_notifiers_); |
| ack_notifiers_.clear(); |
| |
| delegate_->OnSerializedPacket(serialized_packet); |
| MaybeSendFecPacketAndCloseGroup(/*force=*/false); |
| |
| // The packet has now been serialized, so the frames are no longer queued. |
| ack_queued_ = false; |
| stop_waiting_queued_ = false; |
| } |
| |
| void QuicPacketGenerator::StopSendingVersion() { |
| packet_creator_.StopSendingVersion(); |
| } |
| |
| QuicPacketSequenceNumber QuicPacketGenerator::sequence_number() const { |
| return packet_creator_.sequence_number(); |
| } |
| |
| QuicByteCount QuicPacketGenerator::max_packet_length() const { |
| return packet_creator_.max_packet_length(); |
| } |
| |
| void QuicPacketGenerator::set_max_packet_length(QuicByteCount length) { |
| packet_creator_.SetMaxPacketLength(length); |
| } |
| |
| QuicEncryptedPacket* QuicPacketGenerator::SerializeVersionNegotiationPacket( |
| const QuicVersionVector& supported_versions) { |
| return packet_creator_.SerializeVersionNegotiationPacket(supported_versions); |
| } |
| |
| SerializedPacket QuicPacketGenerator::ReserializeAllFrames( |
| const RetransmittableFrames& frames, |
| QuicSequenceNumberLength original_length) { |
| return packet_creator_.ReserializeAllFrames(frames, original_length); |
| } |
| |
| void QuicPacketGenerator::UpdateSequenceNumberLength( |
| QuicPacketSequenceNumber least_packet_awaited_by_peer, |
| QuicPacketCount max_packets_in_flight) { |
| return packet_creator_.UpdateSequenceNumberLength( |
| least_packet_awaited_by_peer, max_packets_in_flight); |
| } |
| |
| void QuicPacketGenerator::SetConnectionIdLength(uint32 length) { |
| if (length == 0) { |
| packet_creator_.set_connection_id_length(PACKET_0BYTE_CONNECTION_ID); |
| } else if (length == 1) { |
| packet_creator_.set_connection_id_length(PACKET_1BYTE_CONNECTION_ID); |
| } else if (length <= 4) { |
| packet_creator_.set_connection_id_length(PACKET_4BYTE_CONNECTION_ID); |
| } else { |
| packet_creator_.set_connection_id_length(PACKET_8BYTE_CONNECTION_ID); |
| } |
| } |
| |
| |
| void QuicPacketGenerator::set_encryption_level(EncryptionLevel level) { |
| packet_creator_.set_encryption_level(level); |
| } |
| |
| void QuicPacketGenerator::SetEncrypter(EncryptionLevel level, |
| QuicEncrypter* encrypter) { |
| packet_creator_.SetEncrypter(level, encrypter); |
| } |
| |
| } // namespace net |