cast: Split Rtcp into two for sender and receiver

media/cast/net/rtcp/sender_rtcp_session.h

+// Copyright 2015 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.
+
+#ifndef MEDIA_CAST_NET_RTCP_SENDER_RTCP_SESSION_H_
+#define MEDIA_CAST_NET_RTCP_SENDER_RTCP_SESSION_H_
+
+#include <hash_set>
+#include <map>
+#include <queue>
+#include <utility>
+
+#include "base/time/time.h"
+#include "media/cast/net/pacing/paced_sender.h"
+#include "media/cast/net/rtcp/rtcp_defines.h"
+#include "media/cast/net/rtcp/rtcp_session.h"
+#include "media/cast/net/rtcp/rtcp_utility.h"
+
+namespace media {
+namespace cast {
+
+typedef std::pair<uint32_t, base::TimeTicks> RtcpSendTimePair;
+typedef std::map<uint32_t, base::TimeTicks> RtcpSendTimeMap;
+typedef std::queue<RtcpSendTimePair> RtcpSendTimeQueue;
+
+// This class represents a RTCP session on a RTP sender. It provides an
+// interface to send RTCP sender report (SR). RTCP SR packets allow
+// receiver to maintain clock offsets and synchronize between audio and video.
+//
+// RTCP session on sender handles the following incoming RTCP reports
+// from receiver:
+// - Receiver reference time report: Helps with tracking largest timestamp
+//   seen and as a result rejecting old RTCP reports.
+// - Receiver logs: The sender receives log events from the receiver and
+//   invokes a callback passed.
+// - cast message: Receives feedback from receiver on missing packets/frames
+//   and last frame id received and invokes a callback passed.
+// - Last report: The receiver provides feedback on delay since last report
+//   received which helps it compute round trip time and invoke a callback.
+class SenderRtcpSession : public RtcpSession {
+ public:
+  SenderRtcpSession(const RtcpCastMessageCallback& cast_callback,
+                    const RtcpRttCallback& rtt_callback,
+                    const RtcpLogMessageCallback& log_callback,
+                    base::TickClock* clock,            // Not owned.
+                    PacedPacketSender* packet_sender,  // Not owned.
+                    uint32_t local_ssrc,
+                    uint32_t remote_ssrc);
+
+  ~SenderRtcpSession() override;
+
+  // If greater than zero, this is the last measured network round trip time.
+  base::TimeDelta current_round_trip_time() const {
+    return current_round_trip_time_;
+  }
+
+  // Send a RTCP sender report.
+  // |current_time| is the current time reported by a tick clock.
+  // |current_time_as_rtp_timestamp| is the corresponding RTP timestamp.
+  // |send_packet_count| is the number of packets sent.
+  // |send_octet_count| is the number of octets sent.
+  void SendRtcpReport(base::TimeTicks current_time,
+                      RtpTimeTicks current_time_as_rtp_timestamp,
+                      uint32_t send_packet_count,
+                      size_t send_octet_count);
+
+  // Handle incoming RTCP packet.
+  // Returns false if it is not a RTCP packet or it is not directed to
+  // this session, e.g. SSRC doesn't match.
+  bool IncomingRtcpPacket(const uint8* data, size_t length) override;
+
+ private:
+  // Received last report information from RTP receiver which helps compute
+  // round trip time.
+  void OnReceivedDelaySinceLastReport(uint32_t last_report,
+                                      uint32_t delay_since_last_report);
+
+  // Received logs from RTP receiver.
+  void OnReceivedReceiverLog(const RtcpReceiverLogMessage& receiver_log);
+
+  // Received cast message containing details of missing packets/frames and
+  // last frame id received.
+  void OnReceivedCastFeedback(const RtcpCastMessage& cast_message);
+
+  // Remove duplicate events in |receiver_log|.
+  // Returns true if any events remain.
+  bool DedupeReceiverLog(RtcpReceiverLogMessage* receiver_log);
+
+  // Save last sent NTP time on RTPC SR. This helps map the sent time when a
+  // last report is received from RTP receiver to compute RTT.
+  void SaveLastSentNtpTime(const base::TimeTicks& now,
+                           uint32_t last_ntp_seconds,
+                           uint32_t last_ntp_fraction);
+
+  base::TickClock* const clock_;      // Not owned.
+  PacedPacketSender* packet_sender_;  // Not owned.
+  const uint32_t local_ssrc_;
+  const uint32_t remote_ssrc_;
+
+  const RtcpCastMessageCallback cast_callback_;
+  const RtcpRttCallback rtt_callback_;
+  const RtcpLogMessageCallback log_callback_;
+
+  // Computed from RTCP RRTR report.
+  base::TimeTicks largest_seen_timestamp_;
+
+  // The RTCP packet parser is re-used when parsing each RTCP packet.  It
+  // remembers state about prior RTP timestamps and other sequence values to
+  // re-construct "expanded" values.
+  RtcpParser parser_;
+
+  // For extending received ACK frame IDs from 8-bit to 32-bit.
+  FrameIdWrapHelper ack_frame_id_wrap_helper_;
+
+  // Maintains a history of receiver events.
+  typedef std::pair<uint64_t, uint64_t> ReceiverEventKey;
+  base::hash_set<ReceiverEventKey> receiver_event_key_set_;
+  std::queue<ReceiverEventKey> receiver_event_key_queue_;
+
+  // The last measured network round trip time.  This is updated with each
+  // sender report --> receiver report round trip.  If this is zero, then the
+  // round trip time has not been measured yet.
+  base::TimeDelta current_round_trip_time_;
+
+  // Map of NTP timestamp to local time that helps with RTT calculation
+  // when last report is received from RTP receiver.
+  RtcpSendTimeMap last_reports_sent_map_;
+  RtcpSendTimeQueue last_reports_sent_queue_;
+
+  DISALLOW_COPY_AND_ASSIGN(SenderRtcpSession);
+};
+
+}  // namespace cast
+}  // namespace media
+
+#endif  // MEDIA_CAST_NET_RTCP_SENDER_RTCP_SESSION_H_