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 // The pure virtual class for send side congestion control algorithm. 6 7 #ifndef NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_ 8 #define NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_ 9 10 #include <algorithm> 11 #include <map> 12 13 #include "base/basictypes.h" 14 #include "net/base/net_export.h" 15 #include "net/quic/quic_bandwidth.h" 16 #include "net/quic/quic_clock.h" 17 #include "net/quic/quic_config.h" 18 #include "net/quic/quic_connection_stats.h" 19 #include "net/quic/quic_protocol.h" 20 #include "net/quic/quic_time.h" 21 22 namespace net { 23 24 class RttStats; 25 26 class NET_EXPORT_PRIVATE SendAlgorithmInterface { 27 public: 28 // A sorted vector of packets. 29 typedef std::vector<std::pair<QuicPacketSequenceNumber, TransmissionInfo>> 30 CongestionVector; 31 32 static SendAlgorithmInterface* Create(const QuicClock* clock, 33 const RttStats* rtt_stats, 34 CongestionControlType type, 35 QuicConnectionStats* stats); 36 ~SendAlgorithmInterface()37 virtual ~SendAlgorithmInterface() {} 38 39 virtual void SetFromConfig(const QuicConfig& config, bool is_server) = 0; 40 41 // Called when we receive congestion feedback from remote peer. 42 virtual void OnIncomingQuicCongestionFeedbackFrame( 43 const QuicCongestionFeedbackFrame& feedback, 44 QuicTime feedback_receive_time) = 0; 45 46 // Indicates an update to the congestion state, caused either by an incoming 47 // ack or loss event timeout. |rtt_updated| indicates whether a new 48 // latest_rtt sample has been taken, |byte_in_flight| the bytes in flight 49 // prior to the congestion event. |acked_packets| and |lost_packets| are 50 // any packets considered acked or lost as a result of the congestion event. 51 virtual void OnCongestionEvent(bool rtt_updated, 52 QuicByteCount bytes_in_flight, 53 const CongestionVector& acked_packets, 54 const CongestionVector& lost_packets) = 0; 55 56 // Inform that we sent |bytes| to the wire, and if the packet is 57 // retransmittable. Returns true if the packet should be tracked by the 58 // congestion manager and included in bytes_in_flight, false otherwise. 59 // |bytes_in_flight| is the number of bytes in flight before the packet was 60 // sent. 61 // Note: this function must be called for every packet sent to the wire. 62 virtual bool OnPacketSent(QuicTime sent_time, 63 QuicByteCount bytes_in_flight, 64 QuicPacketSequenceNumber sequence_number, 65 QuicByteCount bytes, 66 HasRetransmittableData is_retransmittable) = 0; 67 68 // Called when the retransmission timeout fires. Neither OnPacketAbandoned 69 // nor OnPacketLost will be called for these packets. 70 virtual void OnRetransmissionTimeout(bool packets_retransmitted) = 0; 71 72 // Called when the last retransmission timeout was spurious. 73 virtual void RevertRetransmissionTimeout() = 0; 74 75 // Calculate the time until we can send the next packet. 76 virtual QuicTime::Delta TimeUntilSend( 77 QuicTime now, 78 QuicByteCount bytes_in_flight, 79 HasRetransmittableData has_retransmittable_data) const = 0; 80 81 // What's the current estimated bandwidth in bytes per second. 82 // Returns 0 when it does not have an estimate. 83 virtual QuicBandwidth BandwidthEstimate() const = 0; 84 85 // Returns true if the current bandwidth estimate is reliable. 86 virtual bool HasReliableBandwidthEstimate() const = 0; 87 88 // Get the send algorithm specific retransmission delay, called RTO in TCP, 89 // Note 1: the caller is responsible for sanity checking this value. 90 // Note 2: this will return zero if we don't have enough data for an estimate. 91 virtual QuicTime::Delta RetransmissionDelay() const = 0; 92 93 // Returns the size of the current congestion window in bytes. Note, this is 94 // not the *available* window. Some send algorithms may not use a congestion 95 // window and will return 0. 96 virtual QuicByteCount GetCongestionWindow() const = 0; 97 98 // Whether the send algorithm is currently in slow start. When true, the 99 // BandwidthEstimate is expected to be too low. 100 virtual bool InSlowStart() const = 0; 101 102 // Whether the send algorithm is currently in recovery. 103 virtual bool InRecovery() const = 0; 104 105 // Returns the size of the slow start congestion window in bytes, 106 // aka ssthresh. Some send algorithms do not define a slow start 107 // threshold and will return 0. 108 virtual QuicByteCount GetSlowStartThreshold() const = 0; 109 110 virtual CongestionControlType GetCongestionControlType() const = 0; 111 }; 112 113 } // namespace net 114 115 #endif // NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_ 116