modules/congestion_controller/send_side_congestion_controller.cc - src - Git at Google

 /*
  *  Copyright (c) 2012 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 "modules/congestion_controller/include/send_side_congestion_controller.h"

 #include <inttypes.h>
 #include <algorithm>
 #include <cstdio>
 #include <iterator>
 #include <memory>
 #include <string>
 #include <vector>

 #include "absl/memory/memory.h"
 #include "absl/types/optional.h"
 #include "api/units/data_rate.h"
 #include "api/units/timestamp.h"
 #include "modules/bitrate_controller/include/bitrate_controller.h"
 #include "modules/congestion_controller/goog_cc/acknowledged_bitrate_estimator.h"
 #include "modules/congestion_controller/goog_cc/congestion_window_pushback_controller.h"
 #include "modules/congestion_controller/goog_cc/probe_controller.h"
 #include "modules/remote_bitrate_estimator/include/bwe_defines.h"
 #include "rtc_base/checks.h"
 #include "rtc_base/experiments/rate_control_settings.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/network/sent_packet.h"
 #include "rtc_base/rate_limiter.h"
 #include "rtc_base/time_utils.h"

 namespace webrtc {
 namespace {

 const char kPacerPushbackExperiment[] = "WebRTC-PacerPushbackExperiment";
 static const int64_t kRetransmitWindowSizeMs = 500;

 // Makes sure that the bitrate and the min, max values are in valid range.
 static void ClampBitrates(int* bitrate_bps,
                           int* min_bitrate_bps,
                           int* max_bitrate_bps) {
   // TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
   // and that we don't try to set the min bitrate to 0 from any applications.
   // The congestion controller should allow a min bitrate of 0.
   if (*min_bitrate_bps < congestion_controller::GetMinBitrateBps())
     *min_bitrate_bps = congestion_controller::GetMinBitrateBps();
   if (*max_bitrate_bps > 0)
     *max_bitrate_bps = std::max(*min_bitrate_bps, *max_bitrate_bps);
   if (*bitrate_bps > 0)
     *bitrate_bps = std::max(*min_bitrate_bps, *bitrate_bps);
 }

 std::vector<webrtc::PacketFeedback> ReceivedPacketFeedbackVector(
     const std::vector<webrtc::PacketFeedback>& input) {
   std::vector<PacketFeedback> received_packet_feedback_vector;
   auto is_received = [](const webrtc::PacketFeedback& packet_feedback) {
     return packet_feedback.arrival_time_ms !=
            webrtc::PacketFeedback::kNotReceived;
   };
   std::copy_if(input.begin(), input.end(),
                std::back_inserter(received_packet_feedback_vector),
                is_received);
   return received_packet_feedback_vector;
 }

 void SortPacketFeedbackVector(
     std::vector<webrtc::PacketFeedback>* const input) {
   RTC_DCHECK(input);
   std::sort(input->begin(), input->end(), PacketFeedbackComparator());
 }

 bool IsPacerPushbackExperimentEnabled(
     const WebRtcKeyValueConfig* const key_value_config) {
   return key_value_config->Lookup(kPacerPushbackExperiment).find("Enabled") ==
          0;
 }

 }  // namespace

 DEPRECATED_SendSideCongestionController::
     DEPRECATED_SendSideCongestionController(
         Clock* clock,
         Observer* observer,
         RtcEventLog* event_log,
         PacedSender* pacer,
         const WebRtcKeyValueConfig* key_value_config)
     : key_value_config_(key_value_config ? key_value_config
                                          : &field_trial_config_),
       clock_(clock),
       observer_(observer),
       event_log_(event_log),
       pacer_(pacer),
       bitrate_controller_(
           BitrateController::CreateBitrateController(clock_, event_log)),
       acknowledged_bitrate_estimator_(
           absl::make_unique<AcknowledgedBitrateEstimator>(key_value_config_)),
       probe_controller_(new ProbeController(key_value_config_)),
       retransmission_rate_limiter_(
           new RateLimiter(clock, kRetransmitWindowSizeMs)),
       transport_feedback_adapter_(clock_),
       last_reported_bitrate_bps_(0),
       last_reported_fraction_loss_(0),
       last_reported_rtt_(0),
       network_state_(kNetworkUp),
       pause_pacer_(false),
       pacer_paused_(false),
       min_bitrate_bps_(congestion_controller::GetMinBitrateBps()),
       probe_bitrate_estimator_(new ProbeBitrateEstimator(event_log_)),
       delay_based_bwe_(new DelayBasedBwe(key_value_config_, event_log_)),
       was_in_alr_(false),
       send_side_bwe_with_overhead_(
           key_value_config_->Lookup("WebRTC-SendSideBwe-WithOverhead")
               .find("Enabled") == 0),
       transport_overhead_bytes_per_packet_(0),
       pacer_pushback_experiment_(
           IsPacerPushbackExperimentEnabled(key_value_config_)) {
   RateControlSettings experiment_params =
       RateControlSettings::ParseFromKeyValueConfig(key_value_config);
   if (experiment_params.UseCongestionWindow()) {
     cwnd_experiment_parameter_ =
         experiment_params.GetCongestionWindowAdditionalTimeMs();
   }
   if (experiment_params.UseCongestionWindowPushback()) {
     congestion_window_pushback_controller_ =
         absl::make_unique<CongestionWindowPushbackController>(
             key_value_config_);
   }
   delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
 }

 DEPRECATED_SendSideCongestionController::
     ~DEPRECATED_SendSideCongestionController() {}

 void DEPRECATED_SendSideCongestionController::EnableCongestionWindowPushback(
     int64_t accepted_queue_ms,
     uint32_t min_pushback_target_bitrate_bps) {
   RTC_DCHECK(!congestion_window_pushback_controller_)
       << "The congestion pushback is already enabled.";
   RTC_CHECK_GE(accepted_queue_ms, 0)
       << "Accepted must be greater than or equal to 0.";
   RTC_CHECK_GE(min_pushback_target_bitrate_bps, 0)
       << "Min pushback target bitrate must be greater than or equal to 0.";

   cwnd_experiment_parameter_ = accepted_queue_ms;
   congestion_window_pushback_controller_ =
       absl::make_unique<CongestionWindowPushbackController>(
           key_value_config_, min_pushback_target_bitrate_bps);
 }

 void DEPRECATED_SendSideCongestionController::SetAlrLimitedBackoffExperiment(
     bool enable) {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_->SetAlrLimitedBackoffExperiment(enable);
 }

 void DEPRECATED_SendSideCongestionController::SetMaxProbingBitrate(
     int64_t max_probing_bitrate_bps) {
   rtc::CritScope cs(&probe_lock_);
   probe_controller_->SetMaxBitrate(max_probing_bitrate_bps);
 }

 void DEPRECATED_SendSideCongestionController::RegisterPacketFeedbackObserver(
     PacketFeedbackObserver* observer) {
   transport_feedback_adapter_.RegisterPacketFeedbackObserver(observer);
 }

 void DEPRECATED_SendSideCongestionController::DeRegisterPacketFeedbackObserver(
     PacketFeedbackObserver* observer) {
   transport_feedback_adapter_.DeRegisterPacketFeedbackObserver(observer);
 }

 void DEPRECATED_SendSideCongestionController::RegisterNetworkObserver(
     Observer* observer) {
   rtc::CritScope cs(&observer_lock_);
   RTC_DCHECK(observer_ == nullptr);
   observer_ = observer;
 }

 void DEPRECATED_SendSideCongestionController::DeRegisterNetworkObserver(
     Observer* observer) {
   rtc::CritScope cs(&observer_lock_);
   RTC_DCHECK_EQ(observer_, observer);
   observer_ = nullptr;
 }

 void DEPRECATED_SendSideCongestionController::SetBweBitrates(
     int min_bitrate_bps,
     int start_bitrate_bps,
     int max_bitrate_bps) {
   ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
   bitrate_controller_->SetBitrates(start_bitrate_bps, min_bitrate_bps,
                                    max_bitrate_bps);

   {
     rtc::CritScope cs(&probe_lock_);
     SendProbes(probe_controller_->SetBitrates(
         min_bitrate_bps, start_bitrate_bps, max_bitrate_bps,
         clock_->TimeInMilliseconds()));
   }

   {
     rtc::CritScope cs(&bwe_lock_);
     if (start_bitrate_bps > 0)
       delay_based_bwe_->SetStartBitrate(DataRate::bps(start_bitrate_bps));
     min_bitrate_bps_ = min_bitrate_bps;
     delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
   }
   MaybeTriggerOnNetworkChanged();
 }

 void DEPRECATED_SendSideCongestionController::SetAllocatedSendBitrateLimits(
     int64_t min_send_bitrate_bps,
     int64_t max_padding_bitrate_bps,
     int64_t max_total_bitrate_bps) {
   pacer_->SetSendBitrateLimits(min_send_bitrate_bps, max_padding_bitrate_bps);

   rtc::CritScope cs(&probe_lock_);
   SendProbes(probe_controller_->OnMaxTotalAllocatedBitrate(
       max_total_bitrate_bps, clock_->TimeInMilliseconds()));
 }

 // TODO(holmer): Split this up and use SetBweBitrates in combination with
 // OnNetworkRouteChanged.
 void DEPRECATED_SendSideCongestionController::OnNetworkRouteChanged(
     const rtc::NetworkRoute& network_route,
     int bitrate_bps,
     int min_bitrate_bps,
     int max_bitrate_bps) {
   ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
   // TODO(honghaiz): Recreate this object once the bitrate controller is
   // no longer exposed outside SendSideCongestionController.
   bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
                                      max_bitrate_bps);

   transport_feedback_adapter_.SetNetworkIds(network_route.local_network_id,
                                             network_route.remote_network_id);
   {
     rtc::CritScope cs(&bwe_lock_);
     transport_overhead_bytes_per_packet_ = network_route.packet_overhead;
     min_bitrate_bps_ = min_bitrate_bps;
     probe_bitrate_estimator_.reset(new ProbeBitrateEstimator(event_log_));
     delay_based_bwe_.reset(new DelayBasedBwe(key_value_config_, event_log_));
     acknowledged_bitrate_estimator_.reset(
         new AcknowledgedBitrateEstimator(key_value_config_));
     if (bitrate_bps > 0) {
       delay_based_bwe_->SetStartBitrate(DataRate::bps(bitrate_bps));
     }
     delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps));
   }
   {
     rtc::CritScope cs(&probe_lock_);
     probe_controller_->Reset(clock_->TimeInMilliseconds());
     SendProbes(probe_controller_->SetBitrates(min_bitrate_bps, bitrate_bps,
                                               max_bitrate_bps,
                                               clock_->TimeInMilliseconds()));
   }

   MaybeTriggerOnNetworkChanged();
 }

 bool DEPRECATED_SendSideCongestionController::AvailableBandwidth(
     uint32_t* bandwidth) const {
   return bitrate_controller_->AvailableBandwidth(bandwidth);
 }

 RtcpBandwidthObserver*
 DEPRECATED_SendSideCongestionController::GetBandwidthObserver() {
   return bitrate_controller_.get();
 }

 void DEPRECATED_SendSideCongestionController::SetPerPacketFeedbackAvailable(
     bool available) {}

 void DEPRECATED_SendSideCongestionController::EnablePeriodicAlrProbing(
     bool enable) {
   rtc::CritScope cs(&probe_lock_);
   probe_controller_->EnablePeriodicAlrProbing(enable);
 }

 int64_t DEPRECATED_SendSideCongestionController::GetPacerQueuingDelayMs()
     const {
   return IsNetworkDown() ? 0 : pacer_->QueueInMs();
 }

 int64_t DEPRECATED_SendSideCongestionController::GetFirstPacketTimeMs() const {
   return pacer_->FirstSentPacketTimeMs();
 }

 TransportFeedbackObserver*
 DEPRECATED_SendSideCongestionController::GetTransportFeedbackObserver() {
   return this;
 }

 void DEPRECATED_SendSideCongestionController::SignalNetworkState(
     NetworkState state) {
   RTC_LOG(LS_INFO) << "SignalNetworkState "
                    << (state == kNetworkUp ? "Up" : "Down");
   {
     rtc::CritScope cs(&network_state_lock_);
     pause_pacer_ = state == kNetworkDown;
     network_state_ = state;
   }

   {
     rtc::CritScope cs(&probe_lock_);
     NetworkAvailability msg;
     msg.at_time = Timestamp::ms(clock_->TimeInMilliseconds());
     msg.network_available = state == kNetworkUp;
     SendProbes(probe_controller_->OnNetworkAvailability(msg));
   }
   MaybeTriggerOnNetworkChanged();
 }

 void DEPRECATED_SendSideCongestionController::OnSentPacket(
     const rtc::SentPacket& sent_packet) {
   // We're not interested in packets without an id, which may be stun packets,
   // etc, sent on the same transport.
   if (sent_packet.packet_id == -1)
     return;
   transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id,
                                            sent_packet.send_time_ms);
   if (cwnd_experiment_parameter_)
     LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
 }

 void DEPRECATED_SendSideCongestionController::OnRttUpdate(int64_t avg_rtt_ms,
                                                           int64_t max_rtt_ms) {
   rtc::CritScope cs(&bwe_lock_);
   delay_based_bwe_->OnRttUpdate(TimeDelta::ms(avg_rtt_ms));
 }

 int64_t DEPRECATED_SendSideCongestionController::TimeUntilNextProcess() {
   return bitrate_controller_->TimeUntilNextProcess();
 }

 void DEPRECATED_SendSideCongestionController::SendProbes(
     std::vector<ProbeClusterConfig> probe_configs) {
   for (auto probe_config : probe_configs) {
     pacer_->CreateProbeCluster(probe_config.target_data_rate.bps());
   }
 }

 void DEPRECATED_SendSideCongestionController::Process() {
   bool pause_pacer;
   // TODO(holmer): Once this class is running on a task queue we should
   // replace this with a task instead.
   {
     rtc::CritScope lock(&network_state_lock_);
     pause_pacer = pause_pacer_;
   }
   if (pause_pacer && !pacer_paused_) {
     pacer_->Pause();
     pacer_paused_ = true;
   } else if (!pause_pacer && pacer_paused_) {
     pacer_->Resume();
     pacer_paused_ = false;
   }
   bitrate_controller_->Process();

   {
     rtc::CritScope cs(&probe_lock_);
     probe_controller_->SetAlrStartTimeMs(
         pacer_->GetApplicationLimitedRegionStartTime());
     SendProbes(probe_controller_->Process(clock_->TimeInMilliseconds()));
   }
   MaybeTriggerOnNetworkChanged();
 }

 void DEPRECATED_SendSideCongestionController::AddPacket(
     uint32_t ssrc,
     uint16_t sequence_number,
     size_t length,
     const PacedPacketInfo& pacing_info) {
   if (send_side_bwe_with_overhead_) {
     rtc::CritScope cs(&bwe_lock_);
     length += transport_overhead_bytes_per_packet_;
   }
   transport_feedback_adapter_.AddPacket(ssrc, sequence_number, length,
                                         pacing_info);
 }

 void DEPRECATED_SendSideCongestionController::OnTransportFeedback(
     const rtcp::TransportFeedback& feedback) {
   RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
   transport_feedback_adapter_.OnTransportFeedback(feedback);
   std::vector<PacketFeedback> feedback_vector = ReceivedPacketFeedbackVector(
       transport_feedback_adapter_.GetTransportFeedbackVector());
   SortPacketFeedbackVector(&feedback_vector);

   bool currently_in_alr =
       pacer_->GetApplicationLimitedRegionStartTime().has_value();
   if (was_in_alr_ && !currently_in_alr) {
     int64_t now_ms = rtc::TimeMillis();
     acknowledged_bitrate_estimator_->SetAlrEndedTimeMs(now_ms);
     rtc::CritScope cs(&probe_lock_);
     probe_controller_->SetAlrEndedTimeMs(now_ms);
   }
   was_in_alr_ = currently_in_alr;

   acknowledged_bitrate_estimator_->IncomingPacketFeedbackVector(
       feedback_vector);
   DelayBasedBwe::Result result;
   {
     rtc::CritScope cs(&bwe_lock_);
     for (const auto& packet : feedback_vector) {
       if (packet.send_time_ms != PacketFeedback::kNoSendTime &&
           packet.pacing_info.probe_cluster_id != PacedPacketInfo::kNotAProbe) {
         probe_bitrate_estimator_->HandleProbeAndEstimateBitrate(packet);
       }
     }
     result = delay_based_bwe_->IncomingPacketFeedbackVector(
         feedback_vector, acknowledged_bitrate_estimator_->bitrate(),
         probe_bitrate_estimator_->FetchAndResetLastEstimatedBitrate(),
         currently_in_alr, Timestamp::ms(clock_->TimeInMilliseconds()));
   }
   if (result.updated) {
     bitrate_controller_->OnDelayBasedBweResult(result);
     // Update the estimate in the ProbeController, in case we want to probe.
     MaybeTriggerOnNetworkChanged();
   }
   if (result.recovered_from_overuse) {
     rtc::CritScope cs(&probe_lock_);
     probe_controller_->SetAlrStartTimeMs(
         pacer_->GetApplicationLimitedRegionStartTime());
     SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
   } else if (result.backoff_in_alr) {
     rtc::CritScope cs(&probe_lock_);
     SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
   }
   if (cwnd_experiment_parameter_) {
     LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
   }
 }

 void DEPRECATED_SendSideCongestionController::LimitOutstandingBytes(
     size_t num_outstanding_bytes) {
   RTC_DCHECK(cwnd_experiment_parameter_);
   rtc::CritScope lock(&network_state_lock_);
   absl::optional<int64_t> min_rtt_ms =
       transport_feedback_adapter_.GetMinFeedbackLoopRtt();
   // No valid RTT. Could be because send-side BWE isn't used, in which case
   // we don't try to limit the outstanding packets.
   if (!min_rtt_ms)
     return;
   const size_t kMinCwndBytes = 2 * 1500;
   size_t max_outstanding_bytes =
       std::max<size_t>((*min_rtt_ms + *cwnd_experiment_parameter_) *
                            last_reported_bitrate_bps_ / 1000 / 8,
                        kMinCwndBytes);
   if (congestion_window_pushback_controller_) {
     congestion_window_pushback_controller_->UpdateOutstandingData(
         num_outstanding_bytes);
     congestion_window_pushback_controller_->UpdateMaxOutstandingData(
         max_outstanding_bytes);
   } else {
     pause_pacer_ = num_outstanding_bytes > max_outstanding_bytes;
   }
 }

 std::vector<PacketFeedback>
 DEPRECATED_SendSideCongestionController::GetTransportFeedbackVector() const {
   RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
   return transport_feedback_adapter_.GetTransportFeedbackVector();
 }

 void DEPRECATED_SendSideCongestionController::SetPacingFactor(
     float pacing_factor) {
   pacer_->SetPacingFactor(pacing_factor);
 }

 void DEPRECATED_SendSideCongestionController::
     SetAllocatedBitrateWithoutFeedback(uint32_t bitrate_bps) {
 }

 void DEPRECATED_SendSideCongestionController::MaybeTriggerOnNetworkChanged() {
   uint32_t bitrate_bps;
   uint8_t fraction_loss;
   int64_t rtt;
   bool estimate_changed = bitrate_controller_->GetNetworkParameters(
       &bitrate_bps, &fraction_loss, &rtt);
   if (estimate_changed) {
     pacer_->SetEstimatedBitrate(bitrate_bps);
     {
       rtc::CritScope cs(&probe_lock_);
       SendProbes(probe_controller_->SetEstimatedBitrate(
           bitrate_bps, clock_->TimeInMilliseconds()));
     }
     retransmission_rate_limiter_->SetMaxRate(bitrate_bps);
   }

   if (IsNetworkDown()) {
     bitrate_bps = 0;
   } else if (congestion_window_pushback_controller_) {
     rtc::CritScope lock(&network_state_lock_);
     bitrate_bps = congestion_window_pushback_controller_->UpdateTargetBitrate(
         bitrate_bps);
   } else if (!pacer_pushback_experiment_) {
     bitrate_bps = IsSendQueueFull() ? 0 : bitrate_bps;
   } else {
     int64_t queue_length_ms = pacer_->ExpectedQueueTimeMs();

     if (queue_length_ms == 0) {
       encoding_rate_ = 1.0;
     } else if (queue_length_ms > 50) {
       float encoding_rate = 1.0 - queue_length_ms / 1000.0;
       encoding_rate_ = std::min(encoding_rate_, encoding_rate);
       encoding_rate_ = std::max(encoding_rate_, 0.0f);
     }

     bitrate_bps *= encoding_rate_;
     bitrate_bps = bitrate_bps < 50000 ? 0 : bitrate_bps;
   }

   if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) {
     int64_t probing_interval_ms;
     {
       rtc::CritScope cs(&bwe_lock_);
       probing_interval_ms = delay_based_bwe_->GetExpectedBwePeriod().ms();
     }
     {
       rtc::CritScope cs(&observer_lock_);
       if (observer_) {
         observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt,
                                     probing_interval_ms);
       }
     }
   }
 }

 bool DEPRECATED_SendSideCongestionController::
     HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
                                         uint8_t fraction_loss,
                                         int64_t rtt) {
   rtc::CritScope cs(&network_state_lock_);
   bool changed =
       last_reported_bitrate_bps_ != bitrate_bps ||
       (bitrate_bps > 0 && (last_reported_fraction_loss_ != fraction_loss ||
                            last_reported_rtt_ != rtt));
   if (changed && (last_reported_bitrate_bps_ == 0 || bitrate_bps == 0)) {
     RTC_LOG(LS_INFO) << "Bitrate estimate state changed, BWE: " << bitrate_bps
                      << " bps.";
   }
   last_reported_bitrate_bps_ = bitrate_bps;
   last_reported_fraction_loss_ = fraction_loss;
   last_reported_rtt_ = rtt;
   return changed;
 }

 bool DEPRECATED_SendSideCongestionController::IsSendQueueFull() const {
   return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
 }

 bool DEPRECATED_SendSideCongestionController::IsNetworkDown() const {
   rtc::CritScope cs(&network_state_lock_);
   return network_state_ == kNetworkDown;
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2012 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 "modules/congestion_controller/include/send_side_congestion_controller.h"

	#include <inttypes.h>
	#include <algorithm>
	#include <cstdio>
	#include <iterator>
	#include <memory>
	#include <string>
	#include <vector>

	#include "absl/memory/memory.h"
	#include "absl/types/optional.h"
	#include "api/units/data_rate.h"
	#include "api/units/timestamp.h"
	#include "modules/bitrate_controller/include/bitrate_controller.h"
	#include "modules/congestion_controller/goog_cc/acknowledged_bitrate_estimator.h"
	#include "modules/congestion_controller/goog_cc/congestion_window_pushback_controller.h"
	#include "modules/congestion_controller/goog_cc/probe_controller.h"
	#include "modules/remote_bitrate_estimator/include/bwe_defines.h"
	#include "rtc_base/checks.h"
	#include "rtc_base/experiments/rate_control_settings.h"
	#include "rtc_base/logging.h"
	#include "rtc_base/network/sent_packet.h"
	#include "rtc_base/rate_limiter.h"
	#include "rtc_base/time_utils.h"

	namespace webrtc {
	namespace {

	const char kPacerPushbackExperiment[] = "WebRTC-PacerPushbackExperiment";
	static const int64_t kRetransmitWindowSizeMs = 500;

	// Makes sure that the bitrate and the min, max values are in valid range.
	static void ClampBitrates(int* bitrate_bps,
	int* min_bitrate_bps,
	int* max_bitrate_bps) {
	// TODO(holmer): We should make sure the default bitrates are set to 10 kbps,
	// and that we don't try to set the min bitrate to 0 from any applications.
	// The congestion controller should allow a min bitrate of 0.
	if (*min_bitrate_bps < congestion_controller::GetMinBitrateBps())
	*min_bitrate_bps = congestion_controller::GetMinBitrateBps();
	if (*max_bitrate_bps > 0)
	max_bitrate_bps = std::max(min_bitrate_bps, *max_bitrate_bps);
	if (*bitrate_bps > 0)
	bitrate_bps = std::max(min_bitrate_bps, *bitrate_bps);
	}

	std::vector<webrtc::PacketFeedback> ReceivedPacketFeedbackVector(
	const std::vector<webrtc::PacketFeedback>& input) {
	std::vector<PacketFeedback> received_packet_feedback_vector;
	auto is_received = [](const webrtc::PacketFeedback& packet_feedback) {
	return packet_feedback.arrival_time_ms !=
	webrtc::PacketFeedback::kNotReceived;
	};
	std::copy_if(input.begin(), input.end(),
	std::back_inserter(received_packet_feedback_vector),
	is_received);
	return received_packet_feedback_vector;
	}

	void SortPacketFeedbackVector(
	std::vector<webrtc::PacketFeedback>* const input) {
	RTC_DCHECK(input);
	std::sort(input->begin(), input->end(), PacketFeedbackComparator());
	}

	bool IsPacerPushbackExperimentEnabled(
	const WebRtcKeyValueConfig* const key_value_config) {
	return key_value_config->Lookup(kPacerPushbackExperiment).find("Enabled") ==
	0;
	}

	} // namespace

	DEPRECATED_SendSideCongestionController::
	DEPRECATED_SendSideCongestionController(
	Clock* clock,
	Observer* observer,
	RtcEventLog* event_log,
	PacedSender* pacer,
	const WebRtcKeyValueConfig* key_value_config)
	: key_value_config_(key_value_config ? key_value_config
	: &field_trial_config_),
	clock_(clock),
	observer_(observer),
	event_log_(event_log),
	pacer_(pacer),
	bitrate_controller_(
	BitrateController::CreateBitrateController(clock_, event_log)),
	acknowledged_bitrate_estimator_(
	absl::make_unique<AcknowledgedBitrateEstimator>(key_value_config_)),
	probe_controller_(new ProbeController(key_value_config_)),
	retransmission_rate_limiter_(
	new RateLimiter(clock, kRetransmitWindowSizeMs)),
	transport_feedback_adapter_(clock_),
	last_reported_bitrate_bps_(0),
	last_reported_fraction_loss_(0),
	last_reported_rtt_(0),
	network_state_(kNetworkUp),
	pause_pacer_(false),
	pacer_paused_(false),
	min_bitrate_bps_(congestion_controller::GetMinBitrateBps()),
	probe_bitrate_estimator_(new ProbeBitrateEstimator(event_log_)),
	delay_based_bwe_(new DelayBasedBwe(key_value_config_, event_log_)),
	was_in_alr_(false),
	send_side_bwe_with_overhead_(
	key_value_config_->Lookup("WebRTC-SendSideBwe-WithOverhead")
	.find("Enabled") == 0),
	transport_overhead_bytes_per_packet_(0),
	pacer_pushback_experiment_(
	IsPacerPushbackExperimentEnabled(key_value_config_)) {
	RateControlSettings experiment_params =
	RateControlSettings::ParseFromKeyValueConfig(key_value_config);
	if (experiment_params.UseCongestionWindow()) {
	cwnd_experiment_parameter_ =
	experiment_params.GetCongestionWindowAdditionalTimeMs();
	}
	if (experiment_params.UseCongestionWindowPushback()) {
	congestion_window_pushback_controller_ =
	absl::make_unique<CongestionWindowPushbackController>(
	key_value_config_);
	}
	delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
	}

	DEPRECATED_SendSideCongestionController::
	~DEPRECATED_SendSideCongestionController() {}

	void DEPRECATED_SendSideCongestionController::EnableCongestionWindowPushback(
	int64_t accepted_queue_ms,
	uint32_t min_pushback_target_bitrate_bps) {
	RTC_DCHECK(!congestion_window_pushback_controller_)
	<< "The congestion pushback is already enabled.";
	RTC_CHECK_GE(accepted_queue_ms, 0)
	<< "Accepted must be greater than or equal to 0.";
	RTC_CHECK_GE(min_pushback_target_bitrate_bps, 0)
	<< "Min pushback target bitrate must be greater than or equal to 0.";

	cwnd_experiment_parameter_ = accepted_queue_ms;
	congestion_window_pushback_controller_ =
	absl::make_unique<CongestionWindowPushbackController>(
	key_value_config_, min_pushback_target_bitrate_bps);
	}

	void DEPRECATED_SendSideCongestionController::SetAlrLimitedBackoffExperiment(
	bool enable) {
	rtc::CritScope cs(&bwe_lock_);
	delay_based_bwe_->SetAlrLimitedBackoffExperiment(enable);
	}

	void DEPRECATED_SendSideCongestionController::SetMaxProbingBitrate(
	int64_t max_probing_bitrate_bps) {
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->SetMaxBitrate(max_probing_bitrate_bps);
	}

	void DEPRECATED_SendSideCongestionController::RegisterPacketFeedbackObserver(
	PacketFeedbackObserver* observer) {
	transport_feedback_adapter_.RegisterPacketFeedbackObserver(observer);
	}

	void DEPRECATED_SendSideCongestionController::DeRegisterPacketFeedbackObserver(
	PacketFeedbackObserver* observer) {
	transport_feedback_adapter_.DeRegisterPacketFeedbackObserver(observer);
	}

	void DEPRECATED_SendSideCongestionController::RegisterNetworkObserver(
	Observer* observer) {
	rtc::CritScope cs(&observer_lock_);
	RTC_DCHECK(observer_ == nullptr);
	observer_ = observer;
	}

	void DEPRECATED_SendSideCongestionController::DeRegisterNetworkObserver(
	Observer* observer) {
	rtc::CritScope cs(&observer_lock_);
	RTC_DCHECK_EQ(observer_, observer);
	observer_ = nullptr;
	}

	void DEPRECATED_SendSideCongestionController::SetBweBitrates(
	int min_bitrate_bps,
	int start_bitrate_bps,
	int max_bitrate_bps) {
	ClampBitrates(&start_bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
	bitrate_controller_->SetBitrates(start_bitrate_bps, min_bitrate_bps,
	max_bitrate_bps);

	{
	rtc::CritScope cs(&probe_lock_);
	SendProbes(probe_controller_->SetBitrates(
	min_bitrate_bps, start_bitrate_bps, max_bitrate_bps,
	clock_->TimeInMilliseconds()));
	}

	{
	rtc::CritScope cs(&bwe_lock_);
	if (start_bitrate_bps > 0)
	delay_based_bwe_->SetStartBitrate(DataRate::bps(start_bitrate_bps));
	min_bitrate_bps_ = min_bitrate_bps;
	delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps_));
	}
	MaybeTriggerOnNetworkChanged();
	}

	void DEPRECATED_SendSideCongestionController::SetAllocatedSendBitrateLimits(
	int64_t min_send_bitrate_bps,
	int64_t max_padding_bitrate_bps,
	int64_t max_total_bitrate_bps) {
	pacer_->SetSendBitrateLimits(min_send_bitrate_bps, max_padding_bitrate_bps);

	rtc::CritScope cs(&probe_lock_);
	SendProbes(probe_controller_->OnMaxTotalAllocatedBitrate(
	max_total_bitrate_bps, clock_->TimeInMilliseconds()));
	}

	// TODO(holmer): Split this up and use SetBweBitrates in combination with
	// OnNetworkRouteChanged.
	void DEPRECATED_SendSideCongestionController::OnNetworkRouteChanged(
	const rtc::NetworkRoute& network_route,
	int bitrate_bps,
	int min_bitrate_bps,
	int max_bitrate_bps) {
	ClampBitrates(&bitrate_bps, &min_bitrate_bps, &max_bitrate_bps);
	// TODO(honghaiz): Recreate this object once the bitrate controller is
	// no longer exposed outside SendSideCongestionController.
	bitrate_controller_->ResetBitrates(bitrate_bps, min_bitrate_bps,
	max_bitrate_bps);

	transport_feedback_adapter_.SetNetworkIds(network_route.local_network_id,
	network_route.remote_network_id);
	{
	rtc::CritScope cs(&bwe_lock_);
	transport_overhead_bytes_per_packet_ = network_route.packet_overhead;
	min_bitrate_bps_ = min_bitrate_bps;
	probe_bitrate_estimator_.reset(new ProbeBitrateEstimator(event_log_));
	delay_based_bwe_.reset(new DelayBasedBwe(key_value_config_, event_log_));
	acknowledged_bitrate_estimator_.reset(
	new AcknowledgedBitrateEstimator(key_value_config_));
	if (bitrate_bps > 0) {
	delay_based_bwe_->SetStartBitrate(DataRate::bps(bitrate_bps));
	}
	delay_based_bwe_->SetMinBitrate(DataRate::bps(min_bitrate_bps));
	}
	{
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->Reset(clock_->TimeInMilliseconds());
	SendProbes(probe_controller_->SetBitrates(min_bitrate_bps, bitrate_bps,
	max_bitrate_bps,
	clock_->TimeInMilliseconds()));
	}

	MaybeTriggerOnNetworkChanged();
	}

	bool DEPRECATED_SendSideCongestionController::AvailableBandwidth(
	uint32_t* bandwidth) const {
	return bitrate_controller_->AvailableBandwidth(bandwidth);
	}

	RtcpBandwidthObserver*
	DEPRECATED_SendSideCongestionController::GetBandwidthObserver() {
	return bitrate_controller_.get();
	}

	void DEPRECATED_SendSideCongestionController::SetPerPacketFeedbackAvailable(
	bool available) {}

	void DEPRECATED_SendSideCongestionController::EnablePeriodicAlrProbing(
	bool enable) {
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->EnablePeriodicAlrProbing(enable);
	}

	int64_t DEPRECATED_SendSideCongestionController::GetPacerQueuingDelayMs()
	const {
	return IsNetworkDown() ? 0 : pacer_->QueueInMs();
	}

	int64_t DEPRECATED_SendSideCongestionController::GetFirstPacketTimeMs() const {
	return pacer_->FirstSentPacketTimeMs();
	}

	TransportFeedbackObserver*
	DEPRECATED_SendSideCongestionController::GetTransportFeedbackObserver() {
	return this;
	}

	void DEPRECATED_SendSideCongestionController::SignalNetworkState(
	NetworkState state) {
	RTC_LOG(LS_INFO) << "SignalNetworkState "
	<< (state == kNetworkUp ? "Up" : "Down");
	{
	rtc::CritScope cs(&network_state_lock_);
	pause_pacer_ = state == kNetworkDown;
	network_state_ = state;
	}

	{
	rtc::CritScope cs(&probe_lock_);
	NetworkAvailability msg;
	msg.at_time = Timestamp::ms(clock_->TimeInMilliseconds());
	msg.network_available = state == kNetworkUp;
	SendProbes(probe_controller_->OnNetworkAvailability(msg));
	}
	MaybeTriggerOnNetworkChanged();
	}

	void DEPRECATED_SendSideCongestionController::OnSentPacket(
	const rtc::SentPacket& sent_packet) {
	// We're not interested in packets without an id, which may be stun packets,
	// etc, sent on the same transport.
	if (sent_packet.packet_id == -1)
	return;
	transport_feedback_adapter_.OnSentPacket(sent_packet.packet_id,
	sent_packet.send_time_ms);
	if (cwnd_experiment_parameter_)
	LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
	}

	void DEPRECATED_SendSideCongestionController::OnRttUpdate(int64_t avg_rtt_ms,
	int64_t max_rtt_ms) {
	rtc::CritScope cs(&bwe_lock_);
	delay_based_bwe_->OnRttUpdate(TimeDelta::ms(avg_rtt_ms));
	}

	int64_t DEPRECATED_SendSideCongestionController::TimeUntilNextProcess() {
	return bitrate_controller_->TimeUntilNextProcess();
	}

	void DEPRECATED_SendSideCongestionController::SendProbes(
	std::vector<ProbeClusterConfig> probe_configs) {
	for (auto probe_config : probe_configs) {
	pacer_->CreateProbeCluster(probe_config.target_data_rate.bps());
	}
	}

	void DEPRECATED_SendSideCongestionController::Process() {
	bool pause_pacer;
	// TODO(holmer): Once this class is running on a task queue we should
	// replace this with a task instead.
	{
	rtc::CritScope lock(&network_state_lock_);
	pause_pacer = pause_pacer_;
	}
	if (pause_pacer && !pacer_paused_) {
	pacer_->Pause();
	pacer_paused_ = true;
	} else if (!pause_pacer && pacer_paused_) {
	pacer_->Resume();
	pacer_paused_ = false;
	}
	bitrate_controller_->Process();

	{
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->SetAlrStartTimeMs(
	pacer_->GetApplicationLimitedRegionStartTime());
	SendProbes(probe_controller_->Process(clock_->TimeInMilliseconds()));
	}
	MaybeTriggerOnNetworkChanged();
	}

	void DEPRECATED_SendSideCongestionController::AddPacket(
	uint32_t ssrc,
	uint16_t sequence_number,
	size_t length,
	const PacedPacketInfo& pacing_info) {
	if (send_side_bwe_with_overhead_) {
	rtc::CritScope cs(&bwe_lock_);
	length += transport_overhead_bytes_per_packet_;
	}
	transport_feedback_adapter_.AddPacket(ssrc, sequence_number, length,
	pacing_info);
	}

	void DEPRECATED_SendSideCongestionController::OnTransportFeedback(
	const rtcp::TransportFeedback& feedback) {
	RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
	transport_feedback_adapter_.OnTransportFeedback(feedback);
	std::vector<PacketFeedback> feedback_vector = ReceivedPacketFeedbackVector(
	transport_feedback_adapter_.GetTransportFeedbackVector());
	SortPacketFeedbackVector(&feedback_vector);

	bool currently_in_alr =
	pacer_->GetApplicationLimitedRegionStartTime().has_value();
	if (was_in_alr_ && !currently_in_alr) {
	int64_t now_ms = rtc::TimeMillis();
	acknowledged_bitrate_estimator_->SetAlrEndedTimeMs(now_ms);
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->SetAlrEndedTimeMs(now_ms);
	}
	was_in_alr_ = currently_in_alr;

	acknowledged_bitrate_estimator_->IncomingPacketFeedbackVector(
	feedback_vector);
	DelayBasedBwe::Result result;
	{
	rtc::CritScope cs(&bwe_lock_);
	for (const auto& packet : feedback_vector) {
	if (packet.send_time_ms != PacketFeedback::kNoSendTime &&
	packet.pacing_info.probe_cluster_id != PacedPacketInfo::kNotAProbe) {
	probe_bitrate_estimator_->HandleProbeAndEstimateBitrate(packet);
	}
	}
	result = delay_based_bwe_->IncomingPacketFeedbackVector(
	feedback_vector, acknowledged_bitrate_estimator_->bitrate(),
	probe_bitrate_estimator_->FetchAndResetLastEstimatedBitrate(),
	currently_in_alr, Timestamp::ms(clock_->TimeInMilliseconds()));
	}
	if (result.updated) {
	bitrate_controller_->OnDelayBasedBweResult(result);
	// Update the estimate in the ProbeController, in case we want to probe.
	MaybeTriggerOnNetworkChanged();
	}
	if (result.recovered_from_overuse) {
	rtc::CritScope cs(&probe_lock_);
	probe_controller_->SetAlrStartTimeMs(
	pacer_->GetApplicationLimitedRegionStartTime());
	SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
	} else if (result.backoff_in_alr) {
	rtc::CritScope cs(&probe_lock_);
	SendProbes(probe_controller_->RequestProbe(clock_->TimeInMilliseconds()));
	}
	if (cwnd_experiment_parameter_) {
	LimitOutstandingBytes(transport_feedback_adapter_.GetOutstandingBytes());
	}
	}

	void DEPRECATED_SendSideCongestionController::LimitOutstandingBytes(
	size_t num_outstanding_bytes) {
	RTC_DCHECK(cwnd_experiment_parameter_);
	rtc::CritScope lock(&network_state_lock_);
	absl::optional<int64_t> min_rtt_ms =
	transport_feedback_adapter_.GetMinFeedbackLoopRtt();
	// No valid RTT. Could be because send-side BWE isn't used, in which case
	// we don't try to limit the outstanding packets.
	if (!min_rtt_ms)
	return;
	const size_t kMinCwndBytes = 2 * 1500;
	size_t max_outstanding_bytes =
	std::max<size_t>((min_rtt_ms + cwnd_experiment_parameter_) *
	last_reported_bitrate_bps_ / 1000 / 8,
	kMinCwndBytes);
	if (congestion_window_pushback_controller_) {
	congestion_window_pushback_controller_->UpdateOutstandingData(
	num_outstanding_bytes);
	congestion_window_pushback_controller_->UpdateMaxOutstandingData(
	max_outstanding_bytes);
	} else {
	pause_pacer_ = num_outstanding_bytes > max_outstanding_bytes;
	}
	}

	std::vector<PacketFeedback>
	DEPRECATED_SendSideCongestionController::GetTransportFeedbackVector() const {
	RTC_DCHECK_RUNS_SERIALIZED(&worker_race_);
	return transport_feedback_adapter_.GetTransportFeedbackVector();
	}

	void DEPRECATED_SendSideCongestionController::SetPacingFactor(
	float pacing_factor) {
	pacer_->SetPacingFactor(pacing_factor);
	}

	void DEPRECATED_SendSideCongestionController::
	SetAllocatedBitrateWithoutFeedback(uint32_t bitrate_bps) {
	}

	void DEPRECATED_SendSideCongestionController::MaybeTriggerOnNetworkChanged() {
	uint32_t bitrate_bps;
	uint8_t fraction_loss;
	int64_t rtt;
	bool estimate_changed = bitrate_controller_->GetNetworkParameters(
	&bitrate_bps, &fraction_loss, &rtt);
	if (estimate_changed) {
	pacer_->SetEstimatedBitrate(bitrate_bps);
	{
	rtc::CritScope cs(&probe_lock_);
	SendProbes(probe_controller_->SetEstimatedBitrate(
	bitrate_bps, clock_->TimeInMilliseconds()));
	}
	retransmission_rate_limiter_->SetMaxRate(bitrate_bps);
	}

	if (IsNetworkDown()) {
	bitrate_bps = 0;
	} else if (congestion_window_pushback_controller_) {
	rtc::CritScope lock(&network_state_lock_);
	bitrate_bps = congestion_window_pushback_controller_->UpdateTargetBitrate(
	bitrate_bps);
	} else if (!pacer_pushback_experiment_) {
	bitrate_bps = IsSendQueueFull() ? 0 : bitrate_bps;
	} else {
	int64_t queue_length_ms = pacer_->ExpectedQueueTimeMs();

	if (queue_length_ms == 0) {
	encoding_rate_ = 1.0;
	} else if (queue_length_ms > 50) {
	float encoding_rate = 1.0 - queue_length_ms / 1000.0;
	encoding_rate_ = std::min(encoding_rate_, encoding_rate);
	encoding_rate_ = std::max(encoding_rate_, 0.0f);
	}

	bitrate_bps *= encoding_rate_;
	bitrate_bps = bitrate_bps < 50000 ? 0 : bitrate_bps;
	}

	if (HasNetworkParametersToReportChanged(bitrate_bps, fraction_loss, rtt)) {
	int64_t probing_interval_ms;
	{
	rtc::CritScope cs(&bwe_lock_);
	probing_interval_ms = delay_based_bwe_->GetExpectedBwePeriod().ms();
	}
	{
	rtc::CritScope cs(&observer_lock_);
	if (observer_) {
	observer_->OnNetworkChanged(bitrate_bps, fraction_loss, rtt,
	probing_interval_ms);
	}
	}
	}
	}

	bool DEPRECATED_SendSideCongestionController::
	HasNetworkParametersToReportChanged(uint32_t bitrate_bps,
	uint8_t fraction_loss,
	int64_t rtt) {
	rtc::CritScope cs(&network_state_lock_);
	bool changed =
	last_reported_bitrate_bps_ != bitrate_bps \|\|
	(bitrate_bps > 0 && (last_reported_fraction_loss_ != fraction_loss \|\|
	last_reported_rtt_ != rtt));
	if (changed && (last_reported_bitrate_bps_ == 0 \|\| bitrate_bps == 0)) {
	RTC_LOG(LS_INFO) << "Bitrate estimate state changed, BWE: " << bitrate_bps
	<< " bps.";
	}
	last_reported_bitrate_bps_ = bitrate_bps;
	last_reported_fraction_loss_ = fraction_loss;
	last_reported_rtt_ = rtt;
	return changed;
	}

	bool DEPRECATED_SendSideCongestionController::IsSendQueueFull() const {
	return pacer_->ExpectedQueueTimeMs() > PacedSender::kMaxQueueLengthMs;
	}

	bool DEPRECATED_SendSideCongestionController::IsNetworkDown() const {
	rtc::CritScope cs(&network_state_lock_);
	return network_state_ == kNetworkDown;
	}

	} // namespace webrtc