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 24 namespace net { 25 26 class NET_EXPORT_PRIVATE PacingSender : public SendAlgorithmInterface { 27 public: 28 // Create a PacingSender to wrap the specified sender. |alarm_granularity| 29 // indicates to the pacer to send that far into the future, since it should 30 // not expect a callback before that time delta. |initial_packet_burst| is 31 // the number of packets sent without pacing after quiescence. 32 PacingSender(SendAlgorithmInterface* sender, 33 QuicTime::Delta alarm_granularity, 34 uint32 initial_packet_burst); 35 virtual ~PacingSender(); 36 37 // SendAlgorithmInterface methods. 38 virtual void SetFromConfig(const QuicConfig& config, bool is_server) OVERRIDE; 39 virtual void OnIncomingQuicCongestionFeedbackFrame( 40 const QuicCongestionFeedbackFrame& feedback, 41 QuicTime feedback_receive_time) OVERRIDE; 42 virtual void OnCongestionEvent(bool rtt_updated, 43 QuicByteCount bytes_in_flight, 44 const CongestionVector& acked_packets, 45 const CongestionVector& lost_packets) OVERRIDE; 46 virtual bool OnPacketSent(QuicTime sent_time, 47 QuicByteCount bytes_in_flight, 48 QuicPacketSequenceNumber sequence_number, 49 QuicByteCount bytes, 50 HasRetransmittableData is_retransmittable) OVERRIDE; 51 virtual void OnRetransmissionTimeout(bool packets_retransmitted) OVERRIDE; 52 virtual void RevertRetransmissionTimeout() OVERRIDE; 53 virtual QuicTime::Delta TimeUntilSend( 54 QuicTime now, 55 QuicByteCount bytes_in_flight, 56 HasRetransmittableData has_retransmittable_data) const OVERRIDE; 57 virtual QuicBandwidth BandwidthEstimate() const OVERRIDE; 58 virtual bool HasReliableBandwidthEstimate() const OVERRIDE; 59 virtual QuicTime::Delta RetransmissionDelay() const OVERRIDE; 60 virtual QuicByteCount GetCongestionWindow() const OVERRIDE; 61 virtual bool InSlowStart() const OVERRIDE; 62 virtual bool InRecovery() const OVERRIDE; 63 virtual QuicByteCount GetSlowStartThreshold() const OVERRIDE; 64 virtual CongestionControlType GetCongestionControlType() const OVERRIDE; 65 66 private: 67 scoped_ptr<SendAlgorithmInterface> sender_; // Underlying sender. 68 QuicTime::Delta alarm_granularity_; 69 uint32 initial_packet_burst_; 70 mutable uint32 burst_tokens_; 71 // Send time of the last packet considered delayed. 72 QuicTime last_delayed_packet_sent_time_; 73 QuicTime next_packet_send_time_; // When can the next packet be sent. 74 mutable bool was_last_send_delayed_; // True when the last send was delayed. 75 bool has_valid_rtt_; // True if we have at least one RTT update. 76 77 DISALLOW_COPY_AND_ASSIGN(PacingSender); 78 }; 79 80 } // namespace net 81 82 #endif // NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_ 83
