media/cast/net/rtp/rtp_sender.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "media/cast/net/rtp/rtp_sender.h"
   6
   7 #include "base/big_endian.h"
   8 #include "base/logging.h"
   9 #include "base/rand_util.h"
  10 #include "media/cast/net/cast_transport_defines.h"
  11 #include "media/cast/net/pacing/paced_sender.h"
  12
  13 namespace media {
  14 namespace cast {
  15
  16 namespace {
  17
  18 // If there is only one referecne to the packet then copy the
  19 // reference and return.
  20 // Otherwise return a deep copy of the packet.
  21 PacketRef FastCopyPacket(const PacketRef& packet) {
  22   if (packet->HasOneRef())
  23     return packet;
  24   return make_scoped_refptr(new base::RefCountedData<Packet>(packet->data));
  25 }
  26
  27 }  // namespace
  28
  29 RtpSender::RtpSender(
  30     base::TickClock* clock,
  31     const scoped_refptr<base::SingleThreadTaskRunner>& transport_task_runner,
  32     PacedSender* const transport)
  33     : clock_(clock),
  34       transport_(transport),
  35       transport_task_runner_(transport_task_runner),
  36       weak_factory_(this) {
  37   // Randomly set sequence number start value.
  38   config_.sequence_number = base::RandInt(0, 65535);
  39 }
  40
  41 RtpSender::~RtpSender() {}
  42
  43 bool RtpSender::Initialize(const CastTransportRtpConfig& config) {
  44   storage_.reset(new PacketStorage(config.stored_frames));
  45   if (!storage_->IsValid()) {
  46     return false;
  47   }
  48   config_.ssrc = config.ssrc;
  49   config_.payload_type = config.rtp_payload_type;
  50   packetizer_.reset(new RtpPacketizer(transport_, storage_.get(), config_));
  51   return true;
  52 }
  53
  54 void RtpSender::SendFrame(const EncodedFrame& frame) {
  55   DCHECK(packetizer_);
  56   packetizer_->SendFrameAsPackets(frame);
  57 }
  58
  59 void RtpSender::ResendPackets(
  60     const MissingFramesAndPacketsMap& missing_frames_and_packets,
  61     bool cancel_rtx_if_not_in_list,
  62     base::TimeDelta dedupe_window) {
  63   DCHECK(storage_);
  64   // Iterate over all frames in the list.
  65   for (MissingFramesAndPacketsMap::const_iterator it =
  66            missing_frames_and_packets.begin();
  67        it != missing_frames_and_packets.end();
  68        ++it) {
  69     SendPacketVector packets_to_resend;
  70     uint8 frame_id = it->first;
  71     // Set of packets that the receiver wants us to re-send.
  72     // If empty, we need to re-send all packets for this frame.
  73     const PacketIdSet& missing_packet_set = it->second;
  74
  75     bool resend_all = missing_packet_set.find(kRtcpCastAllPacketsLost) !=
  76         missing_packet_set.end();
  77     bool resend_last = missing_packet_set.find(kRtcpCastLastPacket) !=
  78         missing_packet_set.end();
  79
  80     const SendPacketVector* stored_packets = storage_->GetFrame8(frame_id);
  81     if (!stored_packets)
  82       continue;
  83
  84     for (SendPacketVector::const_iterator it = stored_packets->begin();
  85          it != stored_packets->end(); ++it) {
  86       const PacketKey& packet_key = it->first;
  87       const uint16 packet_id = packet_key.second.second;
  88
  89       // Should we resend the packet?
  90       bool resend = resend_all;
  91
  92       // Should we resend it because it's in the missing_packet_set?
  93       if (!resend &&
  94           missing_packet_set.find(packet_id) != missing_packet_set.end()) {
  95         resend = true;
  96       }
  97
  98       // If we were asked to resend the last packet, check if it's the
  99       // last packet.
 100       if (!resend && resend_last && (it + 1) == stored_packets->end()) {
 101         resend = true;
 102       }
 103
 104       if (resend) {
 105         // Resend packet to the network.
 106         VLOG(3) << "Resend " << static_cast<int>(frame_id) << ":"
 107                 << packet_id;
 108         // Set a unique incremental sequence number for every packet.
 109         PacketRef packet_copy = FastCopyPacket(it->second);
 110         UpdateSequenceNumber(&packet_copy->data);
 111         packets_to_resend.push_back(std::make_pair(packet_key, packet_copy));
 112       } else if (cancel_rtx_if_not_in_list) {
 113         transport_->CancelSendingPacket(it->first);
 114       }
 115     }
 116     transport_->ResendPackets(packets_to_resend, dedupe_window);
 117   }
 118 }
 119
 120 void RtpSender::UpdateSequenceNumber(Packet* packet) {
 121   // TODO(miu): This is an abstraction violation.  This needs to be a part of
 122   // the overall packet (de)serialization consolidation.
 123   static const int kByteOffsetToSequenceNumber = 2;
 124   base::BigEndianWriter big_endian_writer(
 125       reinterpret_cast<char*>((&packet->front()) + kByteOffsetToSequenceNumber),
 126       sizeof(uint16));
 127   big_endian_writer.WriteU16(packetizer_->NextSequenceNumber());
 128 }
 129
 130 }  //  namespace cast
 131 }  // namespace media