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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/crypto/cached_network_parameters.h" | |
16 #include "net/quic/quic_bandwidth.h" | |
17 #include "net/quic/quic_clock.h" | |
18 #include "net/quic/quic_config.h" | |
19 #include "net/quic/quic_connection_stats.h" | |
20 #include "net/quic/quic_protocol.h" | |
21 #include "net/quic/quic_time.h" | |
22 | |
23 namespace net { | |
24 | |
25 class RttStats; | |
26 | |
27 class NET_EXPORT_PRIVATE SendAlgorithmInterface { | |
28 public: | |
29 // A sorted vector of packets. | |
30 typedef std::vector<std::pair<QuicPacketSequenceNumber, TransmissionInfo>> | |
31 CongestionVector; | |
32 | |
33 static SendAlgorithmInterface* Create( | |
34 const QuicClock* clock, | |
35 const RttStats* rtt_stats, | |
36 CongestionControlType type, | |
37 QuicConnectionStats* stats, | |
38 QuicPacketCount initial_congestion_window); | |
39 | |
40 virtual ~SendAlgorithmInterface() {} | |
41 | |
42 virtual void SetFromConfig( | |
43 const QuicConfig& config, bool is_server, bool using_pacing) = 0; | |
44 | |
45 // Sets the number of connections to emulate when doing congestion control, | |
46 // particularly for congestion avoidance. Can be set any time. | |
47 virtual void SetNumEmulatedConnections(int num_connections) = 0; | |
48 | |
49 // Indicates an update to the congestion state, caused either by an incoming | |
50 // ack or loss event timeout. |rtt_updated| indicates whether a new | |
51 // latest_rtt sample has been taken, |byte_in_flight| the bytes in flight | |
52 // prior to the congestion event. |acked_packets| and |lost_packets| are | |
53 // any packets considered acked or lost as a result of the congestion event. | |
54 virtual void OnCongestionEvent(bool rtt_updated, | |
55 QuicByteCount bytes_in_flight, | |
56 const CongestionVector& acked_packets, | |
57 const CongestionVector& lost_packets) = 0; | |
58 | |
59 // Inform that we sent |bytes| to the wire, and if the packet is | |
60 // retransmittable. Returns true if the packet should be tracked by the | |
61 // congestion manager and included in bytes_in_flight, false otherwise. | |
62 // |bytes_in_flight| is the number of bytes in flight before the packet was | |
63 // sent. | |
64 // Note: this function must be called for every packet sent to the wire. | |
65 virtual bool OnPacketSent(QuicTime sent_time, | |
66 QuicByteCount bytes_in_flight, | |
67 QuicPacketSequenceNumber sequence_number, | |
68 QuicByteCount bytes, | |
69 HasRetransmittableData is_retransmittable) = 0; | |
70 | |
71 // Called when the retransmission timeout fires. Neither OnPacketAbandoned | |
72 // nor OnPacketLost will be called for these packets. | |
73 virtual void OnRetransmissionTimeout(bool packets_retransmitted) = 0; | |
74 | |
75 // Called when the last retransmission timeout was spurious. | |
76 virtual void RevertRetransmissionTimeout() = 0; | |
77 | |
78 // Calculate the time until we can send the next packet. | |
79 virtual QuicTime::Delta TimeUntilSend( | |
80 QuicTime now, | |
81 QuicByteCount bytes_in_flight, | |
82 HasRetransmittableData has_retransmittable_data) const = 0; | |
83 | |
84 // The pacing rate of the send algorithm. May be zero if the rate is unknown. | |
85 virtual QuicBandwidth PacingRate() const = 0; | |
86 | |
87 // What's the current estimated bandwidth in bytes per second. | |
88 // Returns 0 when it does not have an estimate. | |
89 virtual QuicBandwidth BandwidthEstimate() const = 0; | |
90 | |
91 // Returns true if the current bandwidth estimate is reliable. | |
92 virtual bool HasReliableBandwidthEstimate() const = 0; | |
93 | |
94 // Get the send algorithm specific retransmission delay, called RTO in TCP, | |
95 // Note 1: the caller is responsible for sanity checking this value. | |
96 // Note 2: this will return zero if we don't have enough data for an estimate. | |
97 virtual QuicTime::Delta RetransmissionDelay() const = 0; | |
98 | |
99 // Returns the size of the current congestion window in bytes. Note, this is | |
100 // not the *available* window. Some send algorithms may not use a congestion | |
101 // window and will return 0. | |
102 virtual QuicByteCount GetCongestionWindow() const = 0; | |
103 | |
104 // Whether the send algorithm is currently in slow start. When true, the | |
105 // BandwidthEstimate is expected to be too low. | |
106 virtual bool InSlowStart() const = 0; | |
107 | |
108 // Whether the send algorithm is currently in recovery. | |
109 virtual bool InRecovery() const = 0; | |
110 | |
111 // Returns the size of the slow start congestion window in bytes, | |
112 // aka ssthresh. Some send algorithms do not define a slow start | |
113 // threshold and will return 0. | |
114 virtual QuicByteCount GetSlowStartThreshold() const = 0; | |
115 | |
116 virtual CongestionControlType GetCongestionControlType() const = 0; | |
117 | |
118 // Called by the Session when we get a bandwidth estimate from the client. | |
119 // Returns true if initial connection state is changed as a result. | |
120 virtual bool ResumeConnectionState( | |
121 const CachedNetworkParameters& cached_network_params) = 0; | |
122 }; | |
123 | |
124 } // namespace net | |
125 | |
126 #endif // NET_QUIC_CONGESTION_CONTROL_SEND_ALGORITHM_INTERFACE_H_ | |
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