| // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| // |
| // Tracks information about an FEC group, including the packets |
| // that have been seen, and the running parity. Provided the ability |
| // to revive a dropped packet. |
| |
| #ifndef NET_QUIC_QUIC_FEC_GROUP_H_ |
| #define NET_QUIC_QUIC_FEC_GROUP_H_ |
| |
| #include "base/strings/string_piece.h" |
| #include "net/quic/quic_protocol.h" |
| |
| namespace net { |
| |
| class NET_EXPORT_PRIVATE QuicFecGroup { |
| public: |
| QuicFecGroup(); |
| ~QuicFecGroup(); |
| |
| // Updates the FEC group based on the delivery of a data packet decrypted at |
| // |encryption_level|. Returns false if this packet has already been seen, |
| // true otherwise. |
| bool Update(EncryptionLevel encryption_level, |
| const QuicPacketHeader& header, |
| base::StringPiece decrypted_payload); |
| |
| // Updates the FEC group based on the delivery of an FEC packet decrypted at |
| // |encryption_level|. Returns false if this packet has already been seen or |
| // if it does not claim to protect all the packets previously seen in this |
| // group. |
| bool UpdateFec(EncryptionLevel encryption_level, |
| QuicPacketSequenceNumber fec_packet_sequence_number, |
| const QuicFecData& fec); |
| |
| // Returns true if a packet can be revived from this FEC group. |
| bool CanRevive() const; |
| |
| // Returns true if all packets (FEC and data) from this FEC group have been |
| // seen or revived |
| bool IsFinished() const; |
| |
| // Revives the missing packet from this FEC group. This may return a packet |
| // that is null padded to a greater length than the original packet, but |
| // the framer will handle it correctly. Returns the length of the data |
| // written to |decrypted_payload|, or 0 if the packet could not be revived. |
| size_t Revive(QuicPacketHeader* header, |
| char* decrypted_payload, |
| size_t decrypted_payload_len); |
| |
| // Returns true of this FEC group protects any packets with sequence |
| // numbers less than |num|. |
| bool ProtectsPacketsBefore(QuicPacketSequenceNumber num) const; |
| |
| const base::StringPiece payload_parity() const { |
| return base::StringPiece(payload_parity_, payload_parity_len_); |
| } |
| |
| QuicPacketSequenceNumber min_protected_packet() const { |
| return min_protected_packet_; |
| } |
| |
| size_t NumReceivedPackets() const { |
| return received_packets_.size(); |
| } |
| |
| // Returns the effective encryption level of the FEC group. |
| EncryptionLevel effective_encryption_level() const { |
| return effective_encryption_level_; |
| } |
| |
| private: |
| bool UpdateParity(base::StringPiece payload); |
| // Returns the number of missing packets, or size_t max if the number |
| // of missing packets is not known. |
| size_t NumMissingPackets() const; |
| |
| // Set of packets that we have recevied. |
| SequenceNumberSet received_packets_; |
| // Sequence number of the first protected packet in this group (the one |
| // with the lowest packet sequence number). Will only be set once the FEC |
| // packet has been seen. |
| QuicPacketSequenceNumber min_protected_packet_; |
| // Sequence number of the last protected packet in this group (the one |
| // with the highest packet sequence number). Will only be set once the FEC |
| // packet has been seen. |
| QuicPacketSequenceNumber max_protected_packet_; |
| // The cumulative parity calculation of all received packets. |
| char payload_parity_[kMaxPacketSize]; |
| size_t payload_parity_len_; |
| // The effective encryption level, which is the lowest encryption level of |
| // the data and FEC in the group. |
| EncryptionLevel effective_encryption_level_; |
| |
| DISALLOW_COPY_AND_ASSIGN(QuicFecGroup); |
| }; |
| |
| } // namespace net |
| |
| #endif // NET_QUIC_QUIC_FEC_GROUP_H_ |