tor-browser

The Tor Browser
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receive_side_congestion_controller.h (3998B)

      1 /*
      2 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #ifndef MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
     12 #define MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_
     13 
     14 #include <cstdint>
     15 #include <memory>
     16 
     17 #include "api/environment/environment.h"
     18 #include "api/media_types.h"
     19 #include "api/sequence_checker.h"
     20 #include "api/units/data_rate.h"
     21 #include "api/units/time_delta.h"
     22 #include "modules/congestion_controller/remb_throttler.h"
     23 #include "modules/include/module_common_types.h"
     24 #include "modules/remote_bitrate_estimator/congestion_control_feedback_generator.h"
     25 #include "modules/remote_bitrate_estimator/transport_sequence_number_feedback_generator.h"
     26 #include "modules/rtp_rtcp/source/rtp_packet_received.h"
     27 #include "rtc_base/synchronization/mutex.h"
     28 #include "rtc_base/thread_annotations.h"
     29 
     30 namespace webrtc {
     31 class RemoteBitrateEstimator;
     32 
     33 // This class represents the congestion control state for receive
     34 // streams. For send side bandwidth estimation, this is simply
     35 // relaying for each received RTP packet back to the sender. While for
     36 // receive side bandwidth estimation, we do the estimation locally and
     37 // send our results back to the sender.
     38 class ReceiveSideCongestionController : public CallStatsObserver {
     39 public:
     40  ReceiveSideCongestionController(
     41      const Environment& env,
     42      TransportSequenceNumberFeedbackGenenerator::RtcpSender feedback_sender,
     43      RembThrottler::RembSender remb_sender);
     44 
     45  ~ReceiveSideCongestionController() override = default;
     46 
     47  void EnableSendCongestionControlFeedbackAccordingToRfc8888();
     48 
     49  void OnReceivedPacket(const RtpPacketReceived& packet, MediaType media_type);
     50 
     51  // Implements CallStatsObserver.
     52  void OnRttUpdate(int64_t avg_rtt_ms, int64_t max_rtt_ms) override;
     53 
     54  // This is send bitrate, used to control the rate of feedback messages.
     55  void OnBitrateChanged(int bitrate_bps);
     56 
     57  // Ensures the remote party is notified of the receive bitrate no larger than
     58  // `bitrate` using RTCP REMB.
     59  void SetMaxDesiredReceiveBitrate(DataRate bitrate);
     60 
     61  // Returns latest receive side bandwidth estimation.
     62  // Returns zero if receive side bandwidth estimation is unavailable.
     63  DataRate LatestReceiveSideEstimate() const;
     64 
     65  // Removes stream from receive side bandwidth estimation.
     66  // Noop if receive side bwe is not used or stream doesn't participate in it.
     67  void RemoveStream(uint32_t ssrc);
     68 
     69  // Runs periodic tasks if it is time to run them, returns time until next
     70  // call to `MaybeProcess` should be non idle.
     71  TimeDelta MaybeProcess();
     72 
     73 private:
     74  void PickEstimator(bool has_absolute_send_time)
     75      RTC_EXCLUSIVE_LOCKS_REQUIRED(mutex_);
     76 
     77  const Environment env_;
     78  RembThrottler remb_throttler_;
     79 
     80  // TODO: bugs.webrtc.org/42224904 - Use sequence checker for all usage of
     81  // ReceiveSideCongestionController. At the time of
     82  // writing OnReceivedPacket and MaybeProcess can unfortunately be called on an
     83  // arbitrary thread by external projects.
     84  SequenceChecker sequence_checker_;
     85 
     86  bool send_rfc8888_congestion_feedback_ = false;
     87  TransportSequenceNumberFeedbackGenenerator
     88      transport_sequence_number_feedback_generator_;
     89  CongestionControlFeedbackGenerator congestion_control_feedback_generator_
     90      RTC_GUARDED_BY(sequence_checker_);
     91 
     92  mutable Mutex mutex_;
     93  std::unique_ptr<RemoteBitrateEstimator> rbe_ RTC_GUARDED_BY(mutex_);
     94  bool using_absolute_send_time_ RTC_GUARDED_BY(mutex_);
     95  uint32_t packets_since_absolute_send_time_ RTC_GUARDED_BY(mutex_);
     96 };
     97 
     98 }  // namespace webrtc
     99 
    100 #endif  // MODULES_CONGESTION_CONTROLLER_INCLUDE_RECEIVE_SIDE_CONGESTION_CONTROLLER_H_