Files
crossdesk/src/qos/congestion_control_feedback_tracker.cc
2025-01-17 17:33:13 +08:00

100 lines
4.0 KiB
C++

/*
* Copyright (c) 2024 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "congestion_control_feedback_tracker.h"
#include <cstdint>
#include <tuple>
#include <vector>
#include "api/units/time_delta.h"
#include "api/units/timestamp.h"
#include "congestion_control_feedback.h"
#include "rtp_packet_received.h"
namespace webrtc {
void CongestionControlFeedbackTracker::ReceivedPacket(
const RtpPacketReceived& packet) {
int64_t unwrapped_sequence_number =
unwrapper_.Unwrap(packet.SequenceNumber());
if (last_sequence_number_in_feedback_ &&
unwrapped_sequence_number < *last_sequence_number_in_feedback_ + 1) {
LOG_WARN(
"Received packet unorderered between feeedback. SSRC: {} Seq: {} last "
"feedback: {}",
packet.Ssrc(), packet.SequenceNumber(),
static_cast<uint16_t>(*last_sequence_number_in_feedback_));
// TODO: bugs.webrtc.org/374550342 - According to spec, the old packets
// should be reported again. But at the moment, we dont store history of
// packet we already reported and thus, they will be reported as lost. Note
// that this is likely not a problem in webrtc since the packets will also
// be removed from the send history when they are first reported as
// received.
last_sequence_number_in_feedback_ = unwrapped_sequence_number - 1;
}
packets_.push_back({packet.Ssrc(), unwrapped_sequence_number,
packet.arrival_time(), packet.ecn()});
}
void CongestionControlFeedbackTracker::AddPacketsToFeedback(
Timestamp feedback_time,
std::vector<rtcp::CongestionControlFeedback::PacketInfo>& packet_feedback) {
if (packets_.empty()) {
return;
}
std::sort(packets_.begin(), packets_.end(),
[](const PacketInfo& a, const PacketInfo& b) {
return std::tie(a.unwrapped_sequence_number, a.arrival_time) <
std::tie(b.unwrapped_sequence_number, b.arrival_time);
});
if (!last_sequence_number_in_feedback_) {
last_sequence_number_in_feedback_ =
packets_.front().unwrapped_sequence_number - 1;
}
auto packet_it = packets_.begin();
uint32_t ssrc = packet_it->ssrc;
for (int64_t sequence_number = *last_sequence_number_in_feedback_ + 1;
sequence_number <= packets_.back().unwrapped_sequence_number;
++sequence_number) {
rtc::EcnMarking ecn = rtc::EcnMarking::kNotEct;
TimeDelta arrival_time_offset = TimeDelta::MinusInfinity();
if (sequence_number == packet_it->unwrapped_sequence_number) {
arrival_time_offset = feedback_time - packet_it->arrival_time;
ecn = packet_it->ecn;
++packet_it;
while (packet_it != packets_.end() &&
packet_it->unwrapped_sequence_number == sequence_number) {
// According to RFC 8888:
// If duplicate copies of a particular RTP packet are received, then
// the arrival time of the first copy to arrive MUST be reported. If
// any of the copies of the duplicated packet are ECN-CE marked, then
// an ECN-CE mark MUST be reported for that packet; otherwise, the ECN
// mark of the first copy to arrive is reported.
if (packet_it->ecn == rtc::EcnMarking::kCe) {
ecn = rtc::EcnMarking::kCe;
}
LOG_WARN("Received duplicate packet ssrc:{} seq:{} ecn:{}", ssrc,
static_cast<uint16_t>(sequence_number), static_cast<int>(ecn));
++packet_it;
}
} // else - the packet has not been received yet.
packet_feedback.push_back({ssrc, static_cast<uint16_t>(sequence_number),
arrival_time_offset, ecn});
}
last_sequence_number_in_feedback_ = packets_.back().unwrapped_sequence_number;
packets_.clear();
}
} // namespace webrtc