1 // Copyright 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.
5 #ifndef NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_
6 #define NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_
16 #include "base/containers/hash_tables.h"
17 #include "base/memory/scoped_ptr.h"
18 #include "net/base/linked_hash_map.h"
19 #include "net/quic/congestion_control/loss_detection_interface.h"
20 #include "net/quic/congestion_control/rtt_stats.h"
21 #include "net/quic/congestion_control/send_algorithm_interface.h"
22 #include "net/quic/quic_ack_notifier_manager.h"
23 #include "net/quic/quic_protocol.h"
24 #include "net/quic/quic_unacked_packet_map.h"
26 NET_EXPORT_PRIVATE extern bool FLAGS_track_retransmission_history;
27 NET_EXPORT_PRIVATE extern bool FLAGS_enable_quic_pacing;
32 class QuicConnectionPeer;
33 class QuicSentPacketManagerPeer;
38 struct QuicConnectionStats;
40 // Class which tracks the set of packets sent on a QUIC connection and contains
41 // a send algorithm to decide when to send new packets. It keeps track of any
42 // retransmittable data associated with each packet. If a packet is
43 // retransmitted, it will keep track of each version of a packet so that if a
44 // previous transmission is acked, the data will not be retransmitted.
45 class NET_EXPORT_PRIVATE QuicSentPacketManager {
47 // Struct to store the pending retransmission information.
48 struct PendingRetransmission {
49 PendingRetransmission(QuicPacketSequenceNumber sequence_number,
50 TransmissionType transmission_type,
51 const RetransmittableFrames& retransmittable_frames,
52 QuicSequenceNumberLength sequence_number_length)
53 : sequence_number(sequence_number),
54 transmission_type(transmission_type),
55 retransmittable_frames(retransmittable_frames),
56 sequence_number_length(sequence_number_length) {
59 QuicPacketSequenceNumber sequence_number;
60 TransmissionType transmission_type;
61 const RetransmittableFrames& retransmittable_frames;
62 QuicSequenceNumberLength sequence_number_length;
65 QuicSentPacketManager(bool is_server,
66 const QuicClock* clock,
67 QuicConnectionStats* stats,
68 CongestionFeedbackType congestion_type);
69 virtual ~QuicSentPacketManager();
71 virtual void SetFromConfig(const QuicConfig& config);
73 // Called when a new packet is serialized. If the packet contains
74 // retransmittable data, it will be added to the unacked packet map.
75 void OnSerializedPacket(const SerializedPacket& serialized_packet);
77 // Called when a packet is retransmitted with a new sequence number.
78 // Replaces the old entry in the unacked packet map with the new
80 void OnRetransmittedPacket(QuicPacketSequenceNumber old_sequence_number,
81 QuicPacketSequenceNumber new_sequence_number);
83 // Processes the incoming ack and returns true if the retransmission or ack
84 // alarm should be reset.
85 bool OnIncomingAck(const ReceivedPacketInfo& received_info,
86 QuicTime ack_receive_time);
88 // Discards any information for the packet corresponding to |sequence_number|.
89 // If this packet has been retransmitted, information on those packets
90 // will be discarded as well. Also discards it from the congestion window if
92 void DiscardUnackedPacket(QuicPacketSequenceNumber sequence_number);
94 // Returns true if the non-FEC packet |sequence_number| is unacked.
95 bool IsUnacked(QuicPacketSequenceNumber sequence_number) const;
97 // Requests retransmission of all unacked packets of |retransmission_type|.
98 void RetransmitUnackedPackets(RetransmissionType retransmission_type);
100 // Returns true if the unacked packet |sequence_number| has retransmittable
101 // frames. This will only return false if the packet has been acked, if a
102 // previous transmission of this packet was ACK'd, or if this packet has been
103 // retransmitted as with different sequence number.
104 bool HasRetransmittableFrames(QuicPacketSequenceNumber sequence_number) const;
106 // Returns true if there are pending retransmissions.
107 bool HasPendingRetransmissions() const;
109 // Retrieves the next pending retransmission.
110 PendingRetransmission NextPendingRetransmission();
112 bool HasUnackedPackets() const;
114 // Returns the smallest sequence number of a serialized packet which has not
115 // been acked by the peer. If there are no unacked packets, returns 0.
116 QuicPacketSequenceNumber GetLeastUnackedSentPacket() const;
118 // Called when a congestion feedback frame is received from peer.
119 virtual void OnIncomingQuicCongestionFeedbackFrame(
120 const QuicCongestionFeedbackFrame& frame,
121 const QuicTime& feedback_receive_time);
123 // Called when we have sent bytes to the peer. This informs the manager both
124 // the number of bytes sent and if they were retransmitted. Returns true if
125 // the sender should reset the retransmission timer.
126 virtual bool OnPacketSent(QuicPacketSequenceNumber sequence_number,
129 TransmissionType transmission_type,
130 HasRetransmittableData has_retransmittable_data);
132 // Called when the retransmission timer expires.
133 virtual void OnRetransmissionTimeout();
135 // Calculate the time until we can send the next packet to the wire.
136 // Note 1: When kUnknownWaitTime is returned, there is no need to poll
137 // TimeUntilSend again until we receive an OnIncomingAckFrame event.
138 // Note 2: Send algorithms may or may not use |retransmit| in their
140 virtual QuicTime::Delta TimeUntilSend(QuicTime now,
141 TransmissionType transmission_type,
142 HasRetransmittableData retransmittable,
143 IsHandshake handshake);
145 // Returns amount of time for delayed ack timer.
146 const QuicTime::Delta DelayedAckTime() const;
148 // Returns the current delay for the retransmission timer, which may send
149 // either a tail loss probe or do a full RTO. Returns QuicTime::Zero() if
150 // there are no retransmittable packets.
151 const QuicTime GetRetransmissionTime() const;
153 // Returns the estimated smoothed RTT calculated by the congestion algorithm.
154 const QuicTime::Delta SmoothedRtt() const;
156 // Returns the estimated bandwidth calculated by the congestion algorithm.
157 QuicBandwidth BandwidthEstimate() const;
159 // Returns the size of the current congestion window in bytes. Note, this is
160 // not the *available* window. Some send algorithms may not use a congestion
161 // window and will return 0.
162 QuicByteCount GetCongestionWindow() const;
164 // Enables pacing if it has not already been enabled, and if
165 // FLAGS_enable_quic_pacing is set.
166 void MaybeEnablePacing();
168 bool using_pacing() const { return using_pacing_; }
171 friend class test::QuicConnectionPeer;
172 friend class test::QuicSentPacketManagerPeer;
174 enum ReceivedByPeer {
176 NOT_RECEIVED_BY_PEER,
179 // The retransmission timer is a single timer which switches modes depending
180 // upon connection state.
181 enum RetransmissionTimeoutMode {
182 // A conventional TCP style RTO.
184 // A tail loss probe. By default, QUIC sends up to two before RTOing.
186 // Retransmission of handshake packets prior to handshake completion.
188 // Re-invoke the loss detection when a packet is not acked before the
189 // loss detection algorithm expects.
193 typedef linked_hash_map<QuicPacketSequenceNumber,
194 TransmissionType> PendingRetransmissionMap;
196 // Process the incoming ack looking for newly ack'd data packets.
197 void HandleAckForSentPackets(const ReceivedPacketInfo& received_info);
199 // Called when a packet is timed out, such as an RTO. Removes the bytes from
200 // the congestion manager, but does not change the congestion window size.
201 void OnPacketAbandoned(QuicPacketSequenceNumber sequence_number);
203 // Returns the current retransmission mode.
204 RetransmissionTimeoutMode GetRetransmissionMode() const;
206 // Retransmits all crypto stream packets.
207 void RetransmitCryptoPackets();
209 // Retransmits the oldest pending packet.
210 void RetransmitOldestPacket();
212 // Retransmits all the packets and abandons by invoking a full RTO.
213 void RetransmitAllPackets();
215 // Returns the timer for retransmitting crypto handshake packets.
216 const QuicTime::Delta GetCryptoRetransmissionDelay() const;
218 // Returns the timer for a new tail loss probe.
219 const QuicTime::Delta GetTailLossProbeDelay() const;
221 // Returns the retransmission timeout, after which a full RTO occurs.
222 const QuicTime::Delta GetRetransmissionDelay() const;
224 // Update the RTT if the ack is for the largest acked sequence number.
225 void MaybeUpdateRTT(const ReceivedPacketInfo& received_info,
226 const QuicTime& ack_receive_time);
228 // Chooses whether to nack retransmit any packets based on the receipt info.
229 // All acks have been handled before this method is invoked.
230 void MaybeRetransmitOnAckFrame(const ReceivedPacketInfo& received_info,
231 const QuicTime& ack_receive_time);
233 // Invokes the loss detection algorithm and loses and retransmits packets if
235 void InvokeLossDetection(QuicTime time);
237 // Marks |sequence_number| as being fully handled, either due to receipt
238 // by the peer, or having been discarded as indecipherable. Returns an
239 // iterator to the next remaining unacked packet.
240 QuicUnackedPacketMap::const_iterator MarkPacketHandled(
241 QuicPacketSequenceNumber sequence_number,
242 ReceivedByPeer received_by_peer);
244 // Request that |sequence_number| be retransmitted after the other pending
245 // retransmissions. Does not add it to the retransmissions if it's already
246 // a pending retransmission.
247 void MarkForRetransmission(QuicPacketSequenceNumber sequence_number,
248 TransmissionType transmission_type);
250 // Newly serialized retransmittable and fec packets are added to this map,
251 // which contains owning pointers to any contained frames. If a packet is
252 // retransmitted, this map will contain entries for both the old and the new
253 // packet. The old packet's retransmittable frames entry will be NULL, while
254 // the new packet's entry will contain the frames to retransmit.
255 // If the old packet is acked before the new packet, then the old entry will
256 // be removed from the map and the new entry's retransmittable frames will be
258 QuicUnackedPacketMap unacked_packets_;
260 // Pending retransmissions which have not been packetized and sent yet.
261 PendingRetransmissionMap pending_retransmissions_;
263 // Tracks if the connection was created by the server.
266 // An AckNotifier can register to be informed when ACKs have been received for
267 // all packets that a given block of data was sent in. The AckNotifierManager
268 // maintains the currently active notifiers.
269 AckNotifierManager ack_notifier_manager_;
271 const QuicClock* clock_;
272 QuicConnectionStats* stats_;
274 scoped_ptr<SendAlgorithmInterface> send_algorithm_;
275 scoped_ptr<LossDetectionInterface> loss_algorithm_;
277 QuicPacketSequenceNumber largest_observed_; // From the most recent ACK.
278 // Number of times the RTO timer has fired in a row without receiving an ack.
279 size_t consecutive_rto_count_;
280 // Number of times the tail loss probe has been sent.
281 size_t consecutive_tlp_count_;
282 // Number of times the crypto handshake has been retransmitted.
283 size_t consecutive_crypto_retransmission_count_;
284 // Maximum number of tail loss probes to send before firing an RTO.
285 size_t max_tail_loss_probes_;
288 DISALLOW_COPY_AND_ASSIGN(QuicSentPacketManager);
293 #endif // NET_QUIC_QUIC_SENT_PACKET_MANAGER_H_