webrtc/modules/rtp_rtcp/source/rtcp_receiver.cc

/*
 *  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 "webrtc/modules/rtp_rtcp/source/rtcp_receiver.h"

#include <assert.h>
#include <string.h>

#include <limits>
#include <memory>
#include <utility>

#include "webrtc/base/checks.h"
#include "webrtc/base/logging.h"
#include "webrtc/base/trace_event.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/bye.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/common_header.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/compound_packet.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/extended_reports.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/fir.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/nack.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/pli.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rapid_resync_request.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/receiver_report.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/remb.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/rpsi.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/sdes.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/sender_report.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/sli.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbn.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/tmmbr.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
#include "webrtc/modules/rtp_rtcp/source/rtcp_utility.h"
#include "webrtc/modules/rtp_rtcp/source/time_util.h"
#include "webrtc/modules/rtp_rtcp/source/tmmbr_help.h"
#include "webrtc/system_wrappers/include/ntp_time.h"

namespace webrtc {
namespace {

using rtcp::CommonHeader;
using rtcp::ReportBlock;
using RTCPHelp::RTCPReceiveInformation;
using RTCPHelp::RTCPReportBlockInformation;

// The number of RTCP time intervals needed to trigger a timeout.
const int kRrTimeoutIntervals = 3;

const int64_t kMaxWarningLogIntervalMs = 10000;

}  // namespace

struct RTCPReceiver::PacketInformation {
  uint32_t packet_type_flags = 0;  // RTCPPacketTypeFlags bit field.

  uint32_t remote_ssrc = 0;
  std::vector<uint16_t> nack_sequence_numbers;
  ReportBlockList report_blocks;
  int64_t rtt_ms = 0;
  uint8_t sli_picture_id = 0;
  uint64_t rpsi_picture_id = 0;
  uint32_t receiver_estimated_max_bitrate_bps = 0;
  std::unique_ptr<rtcp::TransportFeedback> transport_feedback;
};

RTCPReceiver::RTCPReceiver(
    Clock* clock,
    bool receiver_only,
    RtcpPacketTypeCounterObserver* packet_type_counter_observer,
    RtcpBandwidthObserver* rtcp_bandwidth_observer,
    RtcpIntraFrameObserver* rtcp_intra_frame_observer,
    TransportFeedbackObserver* transport_feedback_observer,
    ModuleRtpRtcp* owner)
    : _clock(clock),
      receiver_only_(receiver_only),
      _rtpRtcp(*owner),
      _cbRtcpBandwidthObserver(rtcp_bandwidth_observer),
      _cbRtcpIntraFrameObserver(rtcp_intra_frame_observer),
      _cbTransportFeedbackObserver(transport_feedback_observer),
      main_ssrc_(0),
      _remoteSSRC(0),
      _remoteSenderInfo(),
      _lastReceivedSRNTPsecs(0),
      _lastReceivedSRNTPfrac(0),
      _lastReceivedXRNTPsecs(0),
      _lastReceivedXRNTPfrac(0),
      xr_rrtr_status_(false),
      xr_rr_rtt_ms_(0),
      _receivedInfoMap(),
      _lastReceivedRrMs(0),
      _lastIncreasedSequenceNumberMs(0),
      stats_callback_(NULL),
      packet_type_counter_observer_(packet_type_counter_observer),
      num_skipped_packets_(0),
      last_skipped_packets_warning_(clock->TimeInMilliseconds()) {
  memset(&_remoteSenderInfo, 0, sizeof(_remoteSenderInfo));
}

RTCPReceiver::~RTCPReceiver() {
  ReportBlockMap::iterator it = _receivedReportBlockMap.begin();
  for (; it != _receivedReportBlockMap.end(); ++it) {
    ReportBlockInfoMap* info_map = &(it->second);
    while (!info_map->empty()) {
      ReportBlockInfoMap::iterator it_info = info_map->begin();
      delete it_info->second;
      info_map->erase(it_info);
    }
  }
  while (!_receivedInfoMap.empty()) {
    std::map<uint32_t, RTCPReceiveInformation*>::iterator first =
        _receivedInfoMap.begin();
    delete first->second;
    _receivedInfoMap.erase(first);
  }
}

bool RTCPReceiver::IncomingPacket(const uint8_t* packet, size_t packet_size) {
  if (packet_size == 0) {
    LOG(LS_WARNING) << "Incoming empty RTCP packet";
    return false;
  }

  PacketInformation packet_information;
  if (!ParseCompoundPacket(packet, packet + packet_size, &packet_information))
    return false;
  TriggerCallbacksFromRTCPPacket(packet_information);
  return true;
}

int64_t RTCPReceiver::LastReceivedReceiverReport() const {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  int64_t last_received_rr = -1;
  for (ReceivedInfoMap::const_iterator it = _receivedInfoMap.begin();
       it != _receivedInfoMap.end(); ++it) {
    if (it->second->last_time_received_ms > last_received_rr) {
      last_received_rr = it->second->last_time_received_ms;
    }
  }
  return last_received_rr;
}

void RTCPReceiver::SetRemoteSSRC(uint32_t ssrc) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  // new SSRC reset old reports
  memset(&_remoteSenderInfo, 0, sizeof(_remoteSenderInfo));
  _lastReceivedSRNTPsecs = 0;
  _lastReceivedSRNTPfrac = 0;

  _remoteSSRC = ssrc;
}

uint32_t RTCPReceiver::RemoteSSRC() const {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  return _remoteSSRC;
}

void RTCPReceiver::SetSsrcs(uint32_t main_ssrc,
                            const std::set<uint32_t>& registered_ssrcs) {
  uint32_t old_ssrc = 0;
  {
    rtc::CritScope lock(&_criticalSectionRTCPReceiver);
    old_ssrc = main_ssrc_;
    main_ssrc_ = main_ssrc;
    registered_ssrcs_ = registered_ssrcs;
  }
  {
    if (_cbRtcpIntraFrameObserver && old_ssrc != main_ssrc) {
      _cbRtcpIntraFrameObserver->OnLocalSsrcChanged(old_ssrc, main_ssrc);
    }
  }
}

int32_t RTCPReceiver::RTT(uint32_t remoteSSRC,
                          int64_t* RTT,
                          int64_t* avgRTT,
                          int64_t* minRTT,
                          int64_t* maxRTT) const {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  RTCPReportBlockInformation* reportBlock =
      GetReportBlockInformation(remoteSSRC, main_ssrc_);

  if (reportBlock == NULL) {
    return -1;
  }
  if (RTT) {
    *RTT = reportBlock->RTT;
  }
  if (avgRTT) {
    *avgRTT = reportBlock->avgRTT;
  }
  if (minRTT) {
    *minRTT = reportBlock->minRTT;
  }
  if (maxRTT) {
    *maxRTT = reportBlock->maxRTT;
  }
  return 0;
}

void RTCPReceiver::SetRtcpXrRrtrStatus(bool enable) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  xr_rrtr_status_ = enable;
}

bool RTCPReceiver::GetAndResetXrRrRtt(int64_t* rtt_ms) {
  assert(rtt_ms);
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (xr_rr_rtt_ms_ == 0) {
    return false;
  }
  *rtt_ms = xr_rr_rtt_ms_;
  xr_rr_rtt_ms_ = 0;
  return true;
}

// TODO(pbos): Make this fail when we haven't received NTP.
bool RTCPReceiver::NTP(uint32_t* ReceivedNTPsecs,
                       uint32_t* ReceivedNTPfrac,
                       uint32_t* RTCPArrivalTimeSecs,
                       uint32_t* RTCPArrivalTimeFrac,
                       uint32_t* rtcp_timestamp) const {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (ReceivedNTPsecs) {
    *ReceivedNTPsecs =
        _remoteSenderInfo.NTPseconds;  // NTP from incoming SendReport
  }
  if (ReceivedNTPfrac) {
    *ReceivedNTPfrac = _remoteSenderInfo.NTPfraction;
  }
  if (RTCPArrivalTimeFrac) {
    *RTCPArrivalTimeFrac = _lastReceivedSRNTPfrac;  // local NTP time when we
                                                    // received a RTCP packet
                                                    // with a send block
  }
  if (RTCPArrivalTimeSecs) {
    *RTCPArrivalTimeSecs = _lastReceivedSRNTPsecs;
  }
  if (rtcp_timestamp) {
    *rtcp_timestamp = _remoteSenderInfo.RTPtimeStamp;
  }
  return true;
}

bool RTCPReceiver::LastReceivedXrReferenceTimeInfo(
    rtcp::ReceiveTimeInfo* info) const {
  assert(info);
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (_lastReceivedXRNTPsecs == 0 && _lastReceivedXRNTPfrac == 0) {
    return false;
  }

  info->ssrc = remote_time_info_.ssrc;
  info->last_rr = remote_time_info_.last_rr;

  // Get the delay since last received report (RFC 3611).
  uint32_t receive_time =
      RTCPUtility::MidNtp(_lastReceivedXRNTPsecs, _lastReceivedXRNTPfrac);

  uint32_t ntp_sec = 0;
  uint32_t ntp_frac = 0;
  _clock->CurrentNtp(ntp_sec, ntp_frac);
  uint32_t now = RTCPUtility::MidNtp(ntp_sec, ntp_frac);

  info->delay_since_last_rr = now - receive_time;
  return true;
}

int32_t RTCPReceiver::SenderInfoReceived(RTCPSenderInfo* senderInfo) const {
  assert(senderInfo);
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (_lastReceivedSRNTPsecs == 0) {
    return -1;
  }
  memcpy(senderInfo, &(_remoteSenderInfo), sizeof(RTCPSenderInfo));
  return 0;
}

// statistics
// we can get multiple receive reports when we receive the report from a CE
int32_t RTCPReceiver::StatisticsReceived(
    std::vector<RTCPReportBlock>* receiveBlocks) const {
  assert(receiveBlocks);
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  ReportBlockMap::const_iterator it = _receivedReportBlockMap.begin();
  for (; it != _receivedReportBlockMap.end(); ++it) {
    const ReportBlockInfoMap* info_map = &(it->second);
    ReportBlockInfoMap::const_iterator it_info = info_map->begin();
    for (; it_info != info_map->end(); ++it_info) {
      receiveBlocks->push_back(it_info->second->remoteReceiveBlock);
    }
  }
  return 0;
}

bool RTCPReceiver::ParseCompoundPacket(const uint8_t* packet_begin,
                                       const uint8_t* packet_end,
                                       PacketInformation* packet_information) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  CommonHeader rtcp_block;
  for (const uint8_t* next_block = packet_begin; next_block != packet_end;
       next_block = rtcp_block.NextPacket()) {
    ptrdiff_t remaining_blocks_size = packet_end - next_block;
    RTC_DCHECK_GT(remaining_blocks_size, 0);
    if (!rtcp_block.Parse(next_block, remaining_blocks_size)) {
      if (next_block == packet_begin) {
        // Failed to parse 1st header, nothing was extracted from this packet.
        LOG(LS_WARNING) << "Incoming invalid RTCP packet";
        return false;
      }
      ++num_skipped_packets_;
      break;
    }

    if (packet_type_counter_.first_packet_time_ms == -1)
      packet_type_counter_.first_packet_time_ms = _clock->TimeInMilliseconds();

    switch (rtcp_block.type()) {
      case rtcp::SenderReport::kPacketType:
        HandleSenderReport(rtcp_block, packet_information);
        break;
      case rtcp::ReceiverReport::kPacketType:
        HandleReceiverReport(rtcp_block, packet_information);
        break;
      case rtcp::Sdes::kPacketType:
        HandleSDES(rtcp_block, packet_information);
        break;
      case rtcp::ExtendedReports::kPacketType:
        HandleXr(rtcp_block, packet_information);
        break;
      case rtcp::Bye::kPacketType:
        HandleBYE(rtcp_block);
        break;
      case rtcp::Rtpfb::kPacketType:
        switch (rtcp_block.fmt()) {
          case rtcp::Nack::kFeedbackMessageType:
            HandleNACK(rtcp_block, packet_information);
            break;
          case rtcp::Tmmbr::kFeedbackMessageType:
            HandleTMMBR(rtcp_block, packet_information);
            break;
          case rtcp::Tmmbn::kFeedbackMessageType:
            HandleTMMBN(rtcp_block, packet_information);
            break;
          case rtcp::RapidResyncRequest::kFeedbackMessageType:
            HandleSR_REQ(rtcp_block, packet_information);
            break;
          case rtcp::TransportFeedback::kFeedbackMessageType:
            HandleTransportFeedback(rtcp_block, packet_information);
            break;
          default:
            ++num_skipped_packets_;
            break;
        }
        break;
      case rtcp::Psfb::kPacketType:
        switch (rtcp_block.fmt()) {
          case rtcp::Pli::kFeedbackMessageType:
            HandlePLI(rtcp_block, packet_information);
            break;
          case rtcp::Sli::kFeedbackMessageType:
            HandleSLI(rtcp_block, packet_information);
            break;
          case rtcp::Rpsi::kFeedbackMessageType:
            HandleRPSI(rtcp_block, packet_information);
            break;
          case rtcp::Fir::kFeedbackMessageType:
            HandleFIR(rtcp_block, packet_information);
            break;
          case rtcp::Remb::kFeedbackMessageType:
            HandlePsfbApp(rtcp_block, packet_information);
            break;
          default:
            ++num_skipped_packets_;
            break;
        }
        break;
      default:
        ++num_skipped_packets_;
        break;
    }
  }

  if (packet_type_counter_observer_ != NULL) {
    packet_type_counter_observer_->RtcpPacketTypesCounterUpdated(
        main_ssrc_, packet_type_counter_);
  }

  int64_t now = _clock->TimeInMilliseconds();
  if (now - last_skipped_packets_warning_ >= kMaxWarningLogIntervalMs &&
      num_skipped_packets_ > 0) {
    last_skipped_packets_warning_ = now;
    LOG(LS_WARNING) << num_skipped_packets_
                    << " RTCP blocks were skipped due to being malformed or of "
                       "unrecognized/unsupported type, during the past "
                    << (kMaxWarningLogIntervalMs / 1000) << " second period.";
  }

  return true;
}

void RTCPReceiver::HandleSenderReport(const CommonHeader& rtcp_block,
                                      PacketInformation* packet_information) {
  rtcp::SenderReport sender_report;
  if (!sender_report.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  const uint32_t remoteSSRC = sender_report.sender_ssrc();

  packet_information->remote_ssrc = remoteSSRC;

  RTCPReceiveInformation* ptrReceiveInfo = CreateReceiveInformation(remoteSSRC);
  if (!ptrReceiveInfo)
    return;

  TRACE_EVENT_INSTANT2(TRACE_DISABLED_BY_DEFAULT("webrtc_rtp"), "SR",
                       "remote_ssrc", remoteSSRC, "ssrc", main_ssrc_);

  // Have I received RTP packets from this party?
  if (_remoteSSRC == remoteSSRC) {
    // Only signal that we have received a SR when we accept one.
    packet_information->packet_type_flags |= kRtcpSr;

    // Save the NTP time of this report.
    _remoteSenderInfo.NTPseconds = sender_report.ntp().seconds();
    _remoteSenderInfo.NTPfraction = sender_report.ntp().fractions();
    _remoteSenderInfo.RTPtimeStamp = sender_report.rtp_timestamp();
    _remoteSenderInfo.sendPacketCount = sender_report.sender_packet_count();
    _remoteSenderInfo.sendOctetCount = sender_report.sender_octet_count();

    _clock->CurrentNtp(_lastReceivedSRNTPsecs, _lastReceivedSRNTPfrac);
  } else {
    // We will only store the send report from one source, but
    // we will store all the receive blocks.
    packet_information->packet_type_flags |= kRtcpRr;
  }
  // Update that this remote is alive.
  ptrReceiveInfo->last_time_received_ms = _clock->TimeInMilliseconds();

  for (const rtcp::ReportBlock report_block : sender_report.report_blocks())
    HandleReportBlock(report_block, packet_information, remoteSSRC);
}

void RTCPReceiver::HandleReceiverReport(const CommonHeader& rtcp_block,
                                        PacketInformation* packet_information) {
  rtcp::ReceiverReport receiver_report;
  if (!receiver_report.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  const uint32_t remoteSSRC = receiver_report.sender_ssrc();

  packet_information->remote_ssrc = remoteSSRC;

  RTCPReceiveInformation* ptrReceiveInfo = CreateReceiveInformation(remoteSSRC);
  if (!ptrReceiveInfo)
    return;

  TRACE_EVENT_INSTANT2(TRACE_DISABLED_BY_DEFAULT("webrtc_rtp"), "RR",
                       "remote_ssrc", remoteSSRC, "ssrc", main_ssrc_);

  packet_information->packet_type_flags |= kRtcpRr;

  // Update that this remote is alive.
  ptrReceiveInfo->last_time_received_ms = _clock->TimeInMilliseconds();

  for (const ReportBlock& report_block : receiver_report.report_blocks())
    HandleReportBlock(report_block, packet_information, remoteSSRC);
}

void RTCPReceiver::HandleReportBlock(const ReportBlock& report_block,
                                     PacketInformation* packet_information,
                                     uint32_t remoteSSRC) {
  // This will be called once per report block in the RTCP packet.
  // We filter out all report blocks that are not for us.
  // Each packet has max 31 RR blocks.
  //
  // We can calc RTT if we send a send report and get a report block back.

  // |rtcpPacket.ReportBlockItem.SSRC| is the SSRC identifier of the source to
  // which the information in this reception report block pertains.

  // Filter out all report blocks that are not for us.
  if (registered_ssrcs_.count(report_block.source_ssrc()) == 0)
    return;

  RTCPReportBlockInformation* reportBlock =
      CreateOrGetReportBlockInformation(remoteSSRC, report_block.source_ssrc());
  if (reportBlock == NULL) {
    LOG(LS_WARNING) << "Failed to CreateReportBlockInformation(" << remoteSSRC
                    << ")";
    return;
  }

  _lastReceivedRrMs = _clock->TimeInMilliseconds();
  reportBlock->remoteReceiveBlock.remoteSSRC = remoteSSRC;
  reportBlock->remoteReceiveBlock.sourceSSRC = report_block.source_ssrc();
  reportBlock->remoteReceiveBlock.fractionLost = report_block.fraction_lost();
  reportBlock->remoteReceiveBlock.cumulativeLost =
      report_block.cumulative_lost();
  if (report_block.extended_high_seq_num() >
      reportBlock->remoteReceiveBlock.extendedHighSeqNum) {
    // We have successfully delivered new RTP packets to the remote side after
    // the last RR was sent from the remote side.
    _lastIncreasedSequenceNumberMs = _lastReceivedRrMs;
  }
  reportBlock->remoteReceiveBlock.extendedHighSeqNum =
      report_block.extended_high_seq_num();
  reportBlock->remoteReceiveBlock.jitter = report_block.jitter();
  reportBlock->remoteReceiveBlock.delaySinceLastSR =
      report_block.delay_since_last_sr();
  reportBlock->remoteReceiveBlock.lastSR = report_block.last_sr();

  if (report_block.jitter() > reportBlock->remoteMaxJitter)
    reportBlock->remoteMaxJitter = report_block.jitter();

  int64_t rtt = 0;
  uint32_t send_time = report_block.last_sr();
  // RFC3550, section 6.4.1, LSR field discription states:
  // If no SR has been received yet, the field is set to zero.
  // Receiver rtp_rtcp module is not expected to calculate rtt using
  // Sender Reports even if it accidentally can.
  if (!receiver_only_ && send_time != 0) {
    uint32_t delay = report_block.delay_since_last_sr();
    // Local NTP time.
    uint32_t receive_time = CompactNtp(NtpTime(*_clock));

    // RTT in 1/(2^16) seconds.
    uint32_t rtt_ntp = receive_time - delay - send_time;
    // Convert to 1/1000 seconds (milliseconds).
    rtt = CompactNtpRttToMs(rtt_ntp);
    if (rtt > reportBlock->maxRTT) {
      // Store max RTT.
      reportBlock->maxRTT = rtt;
    }
    if (reportBlock->minRTT == 0) {
      // First RTT.
      reportBlock->minRTT = rtt;
    } else if (rtt < reportBlock->minRTT) {
      // Store min RTT.
      reportBlock->minRTT = rtt;
    }
    // Store last RTT.
    reportBlock->RTT = rtt;

    // store average RTT
    if (reportBlock->numAverageCalcs != 0) {
      float ac = static_cast<float>(reportBlock->numAverageCalcs);
      float newAverage =
          ((ac / (ac + 1)) * reportBlock->avgRTT) + ((1 / (ac + 1)) * rtt);
      reportBlock->avgRTT = static_cast<int64_t>(newAverage + 0.5f);
    } else {
      // First RTT.
      reportBlock->avgRTT = rtt;
    }
    reportBlock->numAverageCalcs++;
  }

  TRACE_COUNTER_ID1(TRACE_DISABLED_BY_DEFAULT("webrtc_rtp"), "RR_RTT",
                    report_block.source_ssrc(), rtt);

  packet_information->rtt_ms = rtt;
  packet_information->report_blocks.push_back(reportBlock->remoteReceiveBlock);
}

RTCPReportBlockInformation* RTCPReceiver::CreateOrGetReportBlockInformation(
    uint32_t remote_ssrc,
    uint32_t source_ssrc) {
  RTCPReportBlockInformation* info =
      GetReportBlockInformation(remote_ssrc, source_ssrc);
  if (info == NULL) {
    info = new RTCPReportBlockInformation;
    _receivedReportBlockMap[source_ssrc][remote_ssrc] = info;
  }
  return info;
}

RTCPReportBlockInformation* RTCPReceiver::GetReportBlockInformation(
    uint32_t remote_ssrc,
    uint32_t source_ssrc) const {
  ReportBlockMap::const_iterator it = _receivedReportBlockMap.find(source_ssrc);
  if (it == _receivedReportBlockMap.end()) {
    return NULL;
  }
  const ReportBlockInfoMap* info_map = &(it->second);
  ReportBlockInfoMap::const_iterator it_info = info_map->find(remote_ssrc);
  if (it_info == info_map->end()) {
    return NULL;
  }
  return it_info->second;
}

RTCPReceiveInformation* RTCPReceiver::CreateReceiveInformation(
    uint32_t remoteSSRC) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  std::map<uint32_t, RTCPReceiveInformation*>::iterator it =
      _receivedInfoMap.find(remoteSSRC);

  if (it != _receivedInfoMap.end()) {
    return it->second;
  }
  RTCPReceiveInformation* receiveInfo = new RTCPReceiveInformation;
  _receivedInfoMap[remoteSSRC] = receiveInfo;
  return receiveInfo;
}

RTCPReceiveInformation* RTCPReceiver::GetReceiveInformation(
    uint32_t remoteSSRC) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  std::map<uint32_t, RTCPReceiveInformation*>::iterator it =
      _receivedInfoMap.find(remoteSSRC);
  if (it == _receivedInfoMap.end()) {
    return NULL;
  }
  return it->second;
}

bool RTCPReceiver::RtcpRrTimeout(int64_t rtcp_interval_ms) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (_lastReceivedRrMs == 0)
    return false;

  int64_t time_out_ms = kRrTimeoutIntervals * rtcp_interval_ms;
  if (_clock->TimeInMilliseconds() > _lastReceivedRrMs + time_out_ms) {
    // Reset the timer to only trigger one log.
    _lastReceivedRrMs = 0;
    return true;
  }
  return false;
}

bool RTCPReceiver::RtcpRrSequenceNumberTimeout(int64_t rtcp_interval_ms) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  if (_lastIncreasedSequenceNumberMs == 0)
    return false;

  int64_t time_out_ms = kRrTimeoutIntervals * rtcp_interval_ms;
  if (_clock->TimeInMilliseconds() >
      _lastIncreasedSequenceNumberMs + time_out_ms) {
    // Reset the timer to only trigger one log.
    _lastIncreasedSequenceNumberMs = 0;
    return true;
  }
  return false;
}

bool RTCPReceiver::UpdateRTCPReceiveInformationTimers() {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  bool updateBoundingSet = false;
  int64_t timeNow = _clock->TimeInMilliseconds();

  std::map<uint32_t, RTCPReceiveInformation*>::iterator receiveInfoIt =
      _receivedInfoMap.begin();

  while (receiveInfoIt != _receivedInfoMap.end()) {
    RTCPReceiveInformation* receiveInfo = receiveInfoIt->second;
    if (receiveInfo == NULL) {
      return updateBoundingSet;
    }
    // time since last received rtcp packet
    // when we dont have a lastTimeReceived and the object is marked
    // readyForDelete it's removed from the map
    if (receiveInfo->last_time_received_ms > 0) {
      /// use audio define since we don't know what interval the remote peer is
      // using
      if ((timeNow - receiveInfo->last_time_received_ms) >
          5 * RTCP_INTERVAL_AUDIO_MS) {
        // no rtcp packet for the last five regular intervals, reset limitations
        receiveInfo->ClearTmmbr();
        // prevent that we call this over and over again
        receiveInfo->last_time_received_ms = 0;
        // send new TMMBN to all channels using the default codec
        updateBoundingSet = true;
      }
      receiveInfoIt++;
    } else if (receiveInfo->ready_for_delete) {
      // store our current receiveInfoItem
      std::map<uint32_t, RTCPReceiveInformation*>::iterator
          receiveInfoItemToBeErased = receiveInfoIt;
      receiveInfoIt++;
      delete receiveInfoItemToBeErased->second;
      _receivedInfoMap.erase(receiveInfoItemToBeErased);
    } else {
      receiveInfoIt++;
    }
  }
  return updateBoundingSet;
}

std::vector<rtcp::TmmbItem> RTCPReceiver::BoundingSet(bool* tmmbr_owner) {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);

  std::map<uint32_t, RTCPReceiveInformation*>::iterator receiveInfoIt =
      _receivedInfoMap.find(_remoteSSRC);

  if (receiveInfoIt == _receivedInfoMap.end()) {
    return std::vector<rtcp::TmmbItem>();
  }
  RTCPReceiveInformation* receiveInfo = receiveInfoIt->second;
  RTC_DCHECK(receiveInfo);

  *tmmbr_owner = TMMBRHelp::IsOwner(receiveInfo->tmmbn, main_ssrc_);
  return receiveInfo->tmmbn;
}

void RTCPReceiver::HandleSDES(const CommonHeader& rtcp_block,
                              PacketInformation* packet_information) {
  rtcp::Sdes sdes;
  if (!sdes.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  for (const rtcp::Sdes::Chunk& chunk : sdes.chunks()) {
    received_cnames_[chunk.ssrc] = chunk.cname;
    {
      rtc::CritScope lock(&_criticalSectionFeedbacks);
      if (stats_callback_)
        stats_callback_->CNameChanged(chunk.cname.c_str(), chunk.ssrc);
    }
  }
  packet_information->packet_type_flags |= kRtcpSdes;
}

void RTCPReceiver::HandleNACK(const CommonHeader& rtcp_block,
                              PacketInformation* packet_information) {
  rtcp::Nack nack;
  if (!nack.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  if (receiver_only_ || main_ssrc_ != nack.media_ssrc())  // Not to us.
    return;

  packet_information->nack_sequence_numbers = nack.packet_ids();
  for (uint16_t packet_id : nack.packet_ids())
    nack_stats_.ReportRequest(packet_id);

  if (!nack.packet_ids().empty()) {
    packet_information->packet_type_flags |= kRtcpNack;
    ++packet_type_counter_.nack_packets;
    packet_type_counter_.nack_requests = nack_stats_.requests();
    packet_type_counter_.unique_nack_requests = nack_stats_.unique_requests();
  }
}

void RTCPReceiver::HandleBYE(const CommonHeader& rtcp_block) {
  rtcp::Bye bye;
  if (!bye.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  // clear our lists
  ReportBlockMap::iterator it = _receivedReportBlockMap.begin();
  for (; it != _receivedReportBlockMap.end(); ++it) {
    ReportBlockInfoMap* info_map = &(it->second);
    ReportBlockInfoMap::iterator it_info = info_map->find(bye.sender_ssrc());
    if (it_info != info_map->end()) {
      delete it_info->second;
      info_map->erase(it_info);
    }
  }

  //  we can't delete it due to TMMBR
  std::map<uint32_t, RTCPReceiveInformation*>::iterator receiveInfoIt =
      _receivedInfoMap.find(bye.sender_ssrc());

  if (receiveInfoIt != _receivedInfoMap.end())
    receiveInfoIt->second->ready_for_delete = true;

  received_cnames_.erase(bye.sender_ssrc());
  xr_rr_rtt_ms_ = 0;
}

void RTCPReceiver::HandleXr(const CommonHeader& rtcp_block,
                            PacketInformation* packet_information) {
  rtcp::ExtendedReports xr;
  if (!xr.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  for (const rtcp::Rrtr& rrtr : xr.rrtrs())
    HandleXrReceiveReferenceTime(xr.sender_ssrc(), rrtr);

  for (const rtcp::Dlrr& dlrr : xr.dlrrs()) {
    for (const rtcp::ReceiveTimeInfo& time_info : dlrr.sub_blocks())
      HandleXrDlrrReportBlock(time_info);
  }
}

void RTCPReceiver::HandleXrReceiveReferenceTime(
    uint32_t sender_ssrc,
    const rtcp::Rrtr& rrtr) {
  remote_time_info_.ssrc = sender_ssrc;
  remote_time_info_.last_rr = CompactNtp(rrtr.ntp());
  _clock->CurrentNtp(_lastReceivedXRNTPsecs, _lastReceivedXRNTPfrac);
}

void RTCPReceiver::HandleXrDlrrReportBlock(const rtcp::ReceiveTimeInfo& rti) {
  if (registered_ssrcs_.count(rti.ssrc) == 0)  // Not to us.
    return;

  // Caller should explicitly enable rtt calculation using extended reports.
  if (!xr_rrtr_status_)
    return;

  // The send_time and delay_rr fields are in units of 1/2^16 sec.
  uint32_t send_time = rti.last_rr;
  // RFC3611, section 4.5, LRR field discription states:
  // If no such block has been received, the field is set to zero.
  if (send_time == 0)
    return;

  uint32_t delay_rr = rti.delay_since_last_rr;
  uint32_t now = CompactNtp(NtpTime(*_clock));

  uint32_t rtt_ntp = now - delay_rr - send_time;
  xr_rr_rtt_ms_ = CompactNtpRttToMs(rtt_ntp);
}

void RTCPReceiver::HandlePLI(const CommonHeader& rtcp_block,
                             PacketInformation* packet_information) {
  rtcp::Pli pli;
  if (!pli.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  if (main_ssrc_ == pli.media_ssrc()) {
    TRACE_EVENT_INSTANT0(TRACE_DISABLED_BY_DEFAULT("webrtc_rtp"), "PLI");

    ++packet_type_counter_.pli_packets;
    // Received a signal that we need to send a new key frame.
    packet_information->packet_type_flags |= kRtcpPli;
  }
}

void RTCPReceiver::HandleTMMBR(const CommonHeader& rtcp_block,
                               PacketInformation* packet_information) {
  rtcp::Tmmbr tmmbr;
  if (!tmmbr.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  uint32_t senderSSRC = tmmbr.sender_ssrc();
  RTCPReceiveInformation* ptrReceiveInfo = GetReceiveInformation(senderSSRC);
  if (!ptrReceiveInfo)  // This remote SSRC must be saved before.
    return;

  if (tmmbr.media_ssrc()) {
    // media_ssrc() SHOULD be 0 if same as SenderSSRC.
    // In relay mode this is a valid number.
    senderSSRC = tmmbr.media_ssrc();
  }

  for (const rtcp::TmmbItem& request : tmmbr.requests()) {
    if (main_ssrc_ == request.ssrc() && request.bitrate_bps()) {
      ptrReceiveInfo->InsertTmmbrItem(senderSSRC, request,
                                      _clock->TimeInMilliseconds());
      packet_information->packet_type_flags |= kRtcpTmmbr;
    }
  }
}

void RTCPReceiver::HandleTMMBN(const CommonHeader& rtcp_block,
                               PacketInformation* packet_information) {
  rtcp::Tmmbn tmmbn;
  if (!tmmbn.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  RTCPReceiveInformation* ptrReceiveInfo =
      GetReceiveInformation(tmmbn.sender_ssrc());
  if (!ptrReceiveInfo)  // This remote SSRC must be saved before.
    return;

  packet_information->packet_type_flags |= kRtcpTmmbn;

  for (const auto& item : tmmbn.items())
    ptrReceiveInfo->tmmbn.push_back(item);
}

void RTCPReceiver::HandleSR_REQ(const CommonHeader& rtcp_block,
                                PacketInformation* packet_information) {
  rtcp::RapidResyncRequest sr_req;
  if (!sr_req.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  packet_information->packet_type_flags |= kRtcpSrReq;
}

void RTCPReceiver::HandleSLI(const CommonHeader& rtcp_block,
                             PacketInformation* packet_information) {
  rtcp::Sli sli;
  if (!sli.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  for (const rtcp::Sli::Macroblocks& item : sli.macroblocks()) {
    // In theory there could be multiple slices lost.
    // Received signal that we need to refresh a slice.
    packet_information->packet_type_flags |= kRtcpSli;
    packet_information->sli_picture_id = item.picture_id();
  }
}

void RTCPReceiver::HandleRPSI(const CommonHeader& rtcp_block,
                              PacketInformation* packet_information) {
  rtcp::Rpsi rpsi;
  if (!rpsi.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  // Received signal that we have a confirmed reference picture.
  packet_information->packet_type_flags |= kRtcpRpsi;
  packet_information->rpsi_picture_id = rpsi.picture_id();
}

void RTCPReceiver::HandlePsfbApp(const CommonHeader& rtcp_block,
                                 PacketInformation* packet_information) {
  rtcp::Remb remb;
  if (remb.Parse(rtcp_block)) {
    packet_information->packet_type_flags |= kRtcpRemb;
    packet_information->receiver_estimated_max_bitrate_bps = remb.bitrate_bps();
    return;
  }

  ++num_skipped_packets_;
}

void RTCPReceiver::HandleFIR(const CommonHeader& rtcp_block,
                             PacketInformation* packet_information) {
  rtcp::Fir fir;
  if (!fir.Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  RTCPReceiveInformation* ptrReceiveInfo =
      GetReceiveInformation(fir.sender_ssrc());

  for (const rtcp::Fir::Request& fir_request : fir.requests()) {
    // Is it our sender that is requested to generate a new keyframe
    if (main_ssrc_ != fir_request.ssrc)
      continue;

    ++packet_type_counter_.fir_packets;

    // rtcpPacket.FIR.MediaSSRC SHOULD be 0 but we ignore to check it
    // we don't know who this originate from
    if (ptrReceiveInfo) {
      // check if we have reported this FIRSequenceNumber before
      if (fir_request.seq_nr != ptrReceiveInfo->last_fir_sequence_number) {
        int64_t now = _clock->TimeInMilliseconds();
        // sanity; don't go crazy with the callbacks
        if ((now - ptrReceiveInfo->last_fir_request_ms) >
            RTCP_MIN_FRAME_LENGTH_MS) {
          ptrReceiveInfo->last_fir_request_ms = now;
          ptrReceiveInfo->last_fir_sequence_number = fir_request.seq_nr;
          // received signal that we need to send a new key frame
          packet_information->packet_type_flags |= kRtcpFir;
        }
      }
    } else {
      // received signal that we need to send a new key frame
      packet_information->packet_type_flags |= kRtcpFir;
    }
  }
}

void RTCPReceiver::HandleTransportFeedback(
    const CommonHeader& rtcp_block,
    PacketInformation* packet_information) {
  std::unique_ptr<rtcp::TransportFeedback> transport_feedback(
      new rtcp::TransportFeedback());
  if (!transport_feedback->Parse(rtcp_block)) {
    ++num_skipped_packets_;
    return;
  }

  packet_information->packet_type_flags |= kRtcpTransportFeedback;
  packet_information->transport_feedback = std::move(transport_feedback);
}

void RTCPReceiver::UpdateTmmbr() {
  // Find bounding set.
  std::vector<rtcp::TmmbItem> bounding =
      TMMBRHelp::FindBoundingSet(TmmbrReceived());

  if (!bounding.empty() && _cbRtcpBandwidthObserver) {
    // We have a new bandwidth estimate on this channel.
    uint64_t bitrate_bps = TMMBRHelp::CalcMinBitrateBps(bounding);
    if (bitrate_bps <= std::numeric_limits<uint32_t>::max())
      _cbRtcpBandwidthObserver->OnReceivedEstimatedBitrate(bitrate_bps);
  }

  // Set bounding set: inform remote clients about the new bandwidth.
  _rtpRtcp.SetTmmbn(std::move(bounding));
}

void RTCPReceiver::RegisterRtcpStatisticsCallback(
    RtcpStatisticsCallback* callback) {
  rtc::CritScope cs(&_criticalSectionFeedbacks);
  stats_callback_ = callback;
}

RtcpStatisticsCallback* RTCPReceiver::GetRtcpStatisticsCallback() {
  rtc::CritScope cs(&_criticalSectionFeedbacks);
  return stats_callback_;
}

// Holding no Critical section
void RTCPReceiver::TriggerCallbacksFromRTCPPacket(
    const PacketInformation& packet_information) {
  // Process TMMBR and REMB first to avoid multiple callbacks
  // to OnNetworkChanged.
  if (packet_information.packet_type_flags & kRtcpTmmbr) {
    // Might trigger a OnReceivedBandwidthEstimateUpdate.
    UpdateTmmbr();
  }
  uint32_t local_ssrc;
  std::set<uint32_t> registered_ssrcs;
  {
    // We don't want to hold this critsect when triggering the callbacks below.
    rtc::CritScope lock(&_criticalSectionRTCPReceiver);
    local_ssrc = main_ssrc_;
    registered_ssrcs = registered_ssrcs_;
  }
  if (!receiver_only_ && (packet_information.packet_type_flags & kRtcpSrReq)) {
    _rtpRtcp.OnRequestSendReport();
  }
  if (!receiver_only_ && (packet_information.packet_type_flags & kRtcpNack)) {
    if (!packet_information.nack_sequence_numbers.empty()) {
      LOG(LS_VERBOSE) << "Incoming NACK length: "
                      << packet_information.nack_sequence_numbers.size();
      _rtpRtcp.OnReceivedNack(packet_information.nack_sequence_numbers);
    }
  }
  {
    // We need feedback that we have received a report block(s) so that we
    // can generate a new packet in a conference relay scenario, one received
    // report can generate several RTCP packets, based on number relayed/mixed
    // a send report block should go out to all receivers.
    if (_cbRtcpIntraFrameObserver) {
      RTC_DCHECK(!receiver_only_);
      if ((packet_information.packet_type_flags & kRtcpPli) ||
          (packet_information.packet_type_flags & kRtcpFir)) {
        if (packet_information.packet_type_flags & kRtcpPli) {
          LOG(LS_VERBOSE) << "Incoming PLI from SSRC "
                          << packet_information.remote_ssrc;
        } else {
          LOG(LS_VERBOSE) << "Incoming FIR from SSRC "
                          << packet_information.remote_ssrc;
        }
        _cbRtcpIntraFrameObserver->OnReceivedIntraFrameRequest(local_ssrc);
      }
      if (packet_information.packet_type_flags & kRtcpSli) {
        _cbRtcpIntraFrameObserver->OnReceivedSLI(
            local_ssrc, packet_information.sli_picture_id);
      }
      if (packet_information.packet_type_flags & kRtcpRpsi) {
        _cbRtcpIntraFrameObserver->OnReceivedRPSI(
            local_ssrc, packet_information.rpsi_picture_id);
      }
    }
    if (_cbRtcpBandwidthObserver) {
      RTC_DCHECK(!receiver_only_);
      if (packet_information.packet_type_flags & kRtcpRemb) {
        LOG(LS_VERBOSE)
            << "Incoming REMB: "
            << packet_information.receiver_estimated_max_bitrate_bps;
        _cbRtcpBandwidthObserver->OnReceivedEstimatedBitrate(
            packet_information.receiver_estimated_max_bitrate_bps);
      }
      if ((packet_information.packet_type_flags & kRtcpSr) ||
          (packet_information.packet_type_flags & kRtcpRr)) {
        int64_t now = _clock->TimeInMilliseconds();
        _cbRtcpBandwidthObserver->OnReceivedRtcpReceiverReport(
            packet_information.report_blocks, packet_information.rtt_ms, now);
      }
    }
    if ((packet_information.packet_type_flags & kRtcpSr) ||
        (packet_information.packet_type_flags & kRtcpRr)) {
      _rtpRtcp.OnReceivedRtcpReportBlocks(packet_information.report_blocks);
    }

    if (_cbTransportFeedbackObserver &&
        (packet_information.packet_type_flags & kRtcpTransportFeedback)) {
      uint32_t media_source_ssrc =
          packet_information.transport_feedback->media_ssrc();
      if (media_source_ssrc == local_ssrc ||
          registered_ssrcs.find(media_source_ssrc) != registered_ssrcs.end()) {
        _cbTransportFeedbackObserver->OnTransportFeedback(
            *packet_information.transport_feedback);
      }
    }
  }

  if (!receiver_only_) {
    rtc::CritScope cs(&_criticalSectionFeedbacks);
    if (stats_callback_) {
      for (const auto& report_block : packet_information.report_blocks) {
        RtcpStatistics stats;
        stats.cumulative_lost = report_block.cumulativeLost;
        stats.extended_max_sequence_number = report_block.extendedHighSeqNum;
        stats.fraction_lost = report_block.fractionLost;
        stats.jitter = report_block.jitter;

        stats_callback_->StatisticsUpdated(stats, report_block.sourceSSRC);
      }
    }
  }
}

int32_t RTCPReceiver::CNAME(uint32_t remoteSSRC,
                            char cName[RTCP_CNAME_SIZE]) const {
  RTC_DCHECK(cName);

  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  auto received_cname_it = received_cnames_.find(remoteSSRC);
  if (received_cname_it == received_cnames_.end())
    return -1;

  size_t length = received_cname_it->second.copy(cName, RTCP_CNAME_SIZE - 1);
  cName[length] = 0;
  return 0;
}

std::vector<rtcp::TmmbItem> RTCPReceiver::TmmbrReceived() const {
  rtc::CritScope lock(&_criticalSectionRTCPReceiver);
  std::vector<rtcp::TmmbItem> candidates;

  int64_t now_ms = _clock->TimeInMilliseconds();

  for (const auto& kv : _receivedInfoMap) {
    RTCPReceiveInformation* receive_info = kv.second;
    RTC_DCHECK(receive_info);
    receive_info->GetTmmbrSet(now_ms, &candidates);
  }
  return candidates;
}

}  // namespace webrtc