1 // Copyright 2014 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 #ifndef NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_ 6 #define NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_ 7 8 #include "net/base/linked_hash_map.h" 9 #include "net/quic/quic_protocol.h" 10 11 namespace net { 12 13 // Class which tracks unacked packets for three purposes: 14 // 1) Track retransmittable data, including multiple transmissions of frames. 15 // 2) Track packets and bytes in flight for congestion control. 16 // 3) Track sent time of packets to provide RTT measurements from acks. 17 class NET_EXPORT_PRIVATE QuicUnackedPacketMap { 18 public: 19 QuicUnackedPacketMap(); 20 ~QuicUnackedPacketMap(); 21 22 // Adds |serialized_packet| to the map. Does not mark it in flight. 23 void AddPacket(const SerializedPacket& serialized_packet); 24 25 // Called when a packet is retransmitted with a new sequence number. 26 // |old_sequence_number| will remain unacked, but will have no 27 // retransmittable data associated with it. |new_sequence_number| will 28 // be both unacked and associated with retransmittable data. 29 void OnRetransmittedPacket(QuicPacketSequenceNumber old_sequence_number, 30 QuicPacketSequenceNumber new_sequence_number, 31 TransmissionType transmission_type); 32 33 // Returns true if the packet |sequence_number| is unacked. 34 bool IsUnacked(QuicPacketSequenceNumber sequence_number) const; 35 36 // Sets the nack count to the max of the current nack count and |min_nacks|. 37 void NackPacket(QuicPacketSequenceNumber sequence_number, 38 size_t min_nacks); 39 40 // Marks |sequence_number| as no longer in flight. 41 void RemoveFromInFlight(QuicPacketSequenceNumber sequence_number); 42 43 // Returns true if the unacked packet |sequence_number| has retransmittable 44 // frames. This will return false if the packet has been acked, if a 45 // previous transmission of this packet was ACK'd, or if this packet has been 46 // retransmitted as with different sequence number, or if the packet never 47 // had any retransmittable packets in the first place. 48 bool HasRetransmittableFrames(QuicPacketSequenceNumber sequence_number) const; 49 50 // Returns true if there are any unacked packets. 51 bool HasUnackedPackets() const; 52 53 // Returns true if there are any unacked packets which have retransmittable 54 // frames. 55 bool HasUnackedRetransmittableFrames() const; 56 57 // Returns the largest sequence number that has been sent. largest_sent_packet()58 QuicPacketSequenceNumber largest_sent_packet() const { 59 return largest_sent_packet_; 60 } 61 62 // Returns the sum of bytes from all packets in flight. bytes_in_flight()63 QuicByteCount bytes_in_flight() const { 64 return bytes_in_flight_; 65 } 66 67 // Returns the smallest sequence number of a serialized packet which has not 68 // been acked by the peer. If there are no unacked packets, returns 0. 69 QuicPacketSequenceNumber GetLeastUnackedSentPacket() const; 70 71 // Sets a packet as sent with the sent time |sent_time|. Marks the packet 72 // as in flight if |set_in_flight| is true. 73 // Packets marked as in flight are expected to be marked as missing when they 74 // don't arrive, indicating the need for retransmission. 75 void SetSent(QuicPacketSequenceNumber sequence_number, 76 QuicTime sent_time, 77 QuicByteCount bytes_sent, 78 bool set_in_flight); 79 80 // Clears up to |num_to_clear| previous transmissions in order to make room 81 // in the ack frame for new acks. 82 void ClearPreviousRetransmissions(size_t num_to_clear); 83 84 typedef linked_hash_map<QuicPacketSequenceNumber, 85 TransmissionInfo> UnackedPacketMap; 86 87 typedef UnackedPacketMap::const_iterator const_iterator; 88 begin()89 const_iterator begin() const { return unacked_packets_.begin(); } end()90 const_iterator end() const { return unacked_packets_.end(); } 91 92 // Returns true if there are unacked packets that are in flight. 93 bool HasInFlightPackets() const; 94 95 // Returns the TransmissionInfo associated with |sequence_number|, which 96 // must be unacked. 97 const TransmissionInfo& GetTransmissionInfo( 98 QuicPacketSequenceNumber sequence_number) const; 99 100 // Returns the time that the last unacked packet was sent. 101 QuicTime GetLastPacketSentTime() const; 102 103 // Returns the time that the first in flight packet was sent. 104 QuicTime GetFirstInFlightPacketSentTime() const; 105 106 // Returns the number of unacked packets. 107 size_t GetNumUnackedPackets() const; 108 109 // Returns true if there are multiple packets in flight. 110 bool HasMultipleInFlightPackets() const; 111 112 // Returns true if there are any pending crypto packets. 113 bool HasPendingCryptoPackets() const; 114 115 // Removes any retransmittable frames from this transmission or an associated 116 // transmission. It removes now useless transmissions, and disconnects any 117 // other packets from other transmissions. 118 void RemoveRetransmittability(QuicPacketSequenceNumber sequence_number); 119 120 // Increases the largest observed. Any packets less or equal to 121 // |largest_acked_packet| are discarded if they are only for the RTT purposes. 122 void IncreaseLargestObserved(QuicPacketSequenceNumber largest_observed); 123 124 private: 125 void MaybeRemoveRetransmittableFrames(TransmissionInfo* transmission_info); 126 127 // Returns true if the packet no longer has a purpose in the map. 128 bool IsPacketUseless(UnackedPacketMap::const_iterator it) const; 129 130 QuicPacketSequenceNumber largest_sent_packet_; 131 QuicPacketSequenceNumber largest_observed_; 132 133 // Newly serialized retransmittable and fec packets are added to this map, 134 // which contains owning pointers to any contained frames. If a packet is 135 // retransmitted, this map will contain entries for both the old and the new 136 // packet. The old packet's retransmittable frames entry will be NULL, while 137 // the new packet's entry will contain the frames to retransmit. 138 // If the old packet is acked before the new packet, then the old entry will 139 // be removed from the map and the new entry's retransmittable frames will be 140 // set to NULL. 141 UnackedPacketMap unacked_packets_; 142 143 size_t bytes_in_flight_; 144 // Number of retransmittable crypto handshake packets. 145 size_t pending_crypto_packet_count_; 146 147 DISALLOW_COPY_AND_ASSIGN(QuicUnackedPacketMap); 148 }; 149 150 } // namespace net 151 152 #endif // NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_ 153