1// Copyright (c) 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// A send algorithm which adds pacing on top of an another send algorithm. 6// It uses the underlying sender's bandwidth estimate to determine the 7// pacing rate to be used. It also takes into consideration the expected 8// resolution of the underlying alarm mechanism to ensure that alarms are 9// not set too aggressively, and to smooth out variations. 10 11#ifndef NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_ 12#define NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_ 13 14#include <map> 15 16#include "base/basictypes.h" 17#include "base/memory/scoped_ptr.h" 18#include "net/quic/congestion_control/send_algorithm_interface.h" 19#include "net/quic/quic_bandwidth.h" 20#include "net/quic/quic_config.h" 21#include "net/quic/quic_protocol.h" 22#include "net/quic/quic_time.h" 23 24namespace net { 25 26class NET_EXPORT_PRIVATE PacingSender : public SendAlgorithmInterface { 27 public: 28 PacingSender(SendAlgorithmInterface* sender, 29 QuicTime::Delta alarm_granularity); 30 virtual ~PacingSender(); 31 32 // SendAlgorithmInterface methods. 33 virtual void SetFromConfig(const QuicConfig& config, bool is_server) OVERRIDE; 34 virtual void OnIncomingQuicCongestionFeedbackFrame( 35 const QuicCongestionFeedbackFrame& feedback, 36 QuicTime feedback_receive_time) OVERRIDE; 37 virtual void OnCongestionEvent(bool rtt_updated, 38 QuicByteCount bytes_in_flight, 39 const CongestionMap& acked_packets, 40 const CongestionMap& lost_packets) OVERRIDE; 41 virtual bool OnPacketSent(QuicTime sent_time, 42 QuicByteCount bytes_in_flight, 43 QuicPacketSequenceNumber sequence_number, 44 QuicByteCount bytes, 45 HasRetransmittableData is_retransmittable) OVERRIDE; 46 virtual void OnRetransmissionTimeout(bool packets_retransmitted) OVERRIDE; 47 virtual QuicTime::Delta TimeUntilSend( 48 QuicTime now, 49 QuicByteCount bytes_in_flight, 50 HasRetransmittableData has_retransmittable_data) const OVERRIDE; 51 virtual QuicBandwidth BandwidthEstimate() const OVERRIDE; 52 virtual QuicTime::Delta RetransmissionDelay() const OVERRIDE; 53 virtual QuicByteCount GetCongestionWindow() const OVERRIDE; 54 55 private: 56 scoped_ptr<SendAlgorithmInterface> sender_; // Underlying sender. 57 QuicTime::Delta alarm_granularity_; 58 // Send time of the last packet considered delayed. 59 QuicTime last_delayed_packet_sent_time_; 60 QuicTime next_packet_send_time_; // When can the next packet be sent. 61 mutable bool was_last_send_delayed_; // True when the last send was delayed. 62 bool has_valid_rtt_; // True if we have at least one RTT update. 63 64 DISALLOW_COPY_AND_ASSIGN(PacingSender); 65}; 66 67} // namespace net 68 69#endif // NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_ 70