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1 /*
2  *  Copyright (c) 2016 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 #include "call/flexfec_receive_stream_impl.h"
12 
13 #include <stddef.h>
14 
15 #include <cstdint>
16 #include <string>
17 #include <utility>
18 
19 #include "api/array_view.h"
20 #include "api/call/transport.h"
21 #include "api/rtp_parameters.h"
22 #include "call/rtp_stream_receiver_controller_interface.h"
23 #include "modules/rtp_rtcp/include/flexfec_receiver.h"
24 #include "modules/rtp_rtcp/include/receive_statistics.h"
25 #include "modules/rtp_rtcp/source/rtp_packet_received.h"
26 #include "rtc_base/checks.h"
27 #include "rtc_base/logging.h"
28 #include "rtc_base/strings/string_builder.h"
29 #include "system_wrappers/include/clock.h"
30 
31 namespace webrtc {
32 
ToString() const33 std::string FlexfecReceiveStream::Config::ToString() const {
34   char buf[1024];
35   rtc::SimpleStringBuilder ss(buf);
36   ss << "{payload_type: " << payload_type;
37   ss << ", remote_ssrc: " << rtp.remote_ssrc;
38   ss << ", local_ssrc: " << rtp.local_ssrc;
39   ss << ", protected_media_ssrcs: [";
40   size_t i = 0;
41   for (; i + 1 < protected_media_ssrcs.size(); ++i)
42     ss << protected_media_ssrcs[i] << ", ";
43   if (!protected_media_ssrcs.empty())
44     ss << protected_media_ssrcs[i];
45   ss << "], transport_cc: " << (rtp.transport_cc ? "on" : "off");
46   ss << ", rtp.extensions: [";
47   i = 0;
48   for (; i + 1 < rtp.extensions.size(); ++i)
49     ss << rtp.extensions[i].ToString() << ", ";
50   if (!rtp.extensions.empty())
51     ss << rtp.extensions[i].ToString();
52   ss << "]}";
53   return ss.str();
54 }
55 
IsCompleteAndEnabled() const56 bool FlexfecReceiveStream::Config::IsCompleteAndEnabled() const {
57   // Check if FlexFEC is enabled.
58   if (payload_type < 0)
59     return false;
60   // Do we have the necessary SSRC information?
61   if (rtp.remote_ssrc == 0)
62     return false;
63   // TODO(brandtr): Update this check when we support multistream protection.
64   if (protected_media_ssrcs.size() != 1u)
65     return false;
66   return true;
67 }
68 
69 namespace {
70 
71 // TODO(brandtr): Update this function when we support multistream protection.
MaybeCreateFlexfecReceiver(Clock * clock,const FlexfecReceiveStream::Config & config,RecoveredPacketReceiver * recovered_packet_receiver)72 std::unique_ptr<FlexfecReceiver> MaybeCreateFlexfecReceiver(
73     Clock* clock,
74     const FlexfecReceiveStream::Config& config,
75     RecoveredPacketReceiver* recovered_packet_receiver) {
76   if (config.payload_type < 0) {
77     RTC_LOG(LS_WARNING)
78         << "Invalid FlexFEC payload type given. "
79            "This FlexfecReceiveStream will therefore be useless.";
80     return nullptr;
81   }
82   RTC_DCHECK_GE(config.payload_type, 0);
83   RTC_DCHECK_LE(config.payload_type, 127);
84   if (config.rtp.remote_ssrc == 0) {
85     RTC_LOG(LS_WARNING)
86         << "Invalid FlexFEC SSRC given. "
87            "This FlexfecReceiveStream will therefore be useless.";
88     return nullptr;
89   }
90   if (config.protected_media_ssrcs.empty()) {
91     RTC_LOG(LS_WARNING)
92         << "No protected media SSRC supplied. "
93            "This FlexfecReceiveStream will therefore be useless.";
94     return nullptr;
95   }
96 
97   if (config.protected_media_ssrcs.size() > 1) {
98     RTC_LOG(LS_WARNING)
99         << "The supplied FlexfecConfig contained multiple protected "
100            "media streams, but our implementation currently only "
101            "supports protecting a single media stream. "
102            "To avoid confusion, disabling FlexFEC completely.";
103     return nullptr;
104   }
105   RTC_DCHECK_EQ(1U, config.protected_media_ssrcs.size());
106   return std::unique_ptr<FlexfecReceiver>(new FlexfecReceiver(
107       clock, config.rtp.remote_ssrc, config.protected_media_ssrcs[0],
108       recovered_packet_receiver));
109 }
110 
CreateRtpRtcpModule(Clock * clock,ReceiveStatistics * receive_statistics,const FlexfecReceiveStreamImpl::Config & config,RtcpRttStats * rtt_stats)111 std::unique_ptr<ModuleRtpRtcpImpl2> CreateRtpRtcpModule(
112     Clock* clock,
113     ReceiveStatistics* receive_statistics,
114     const FlexfecReceiveStreamImpl::Config& config,
115     RtcpRttStats* rtt_stats) {
116   RtpRtcpInterface::Configuration configuration;
117   configuration.audio = false;
118   configuration.receiver_only = true;
119   configuration.clock = clock;
120   configuration.receive_statistics = receive_statistics;
121   configuration.outgoing_transport = config.rtcp_send_transport;
122   configuration.rtt_stats = rtt_stats;
123   configuration.local_media_ssrc = config.rtp.local_ssrc;
124   return ModuleRtpRtcpImpl2::Create(configuration);
125 }
126 
127 }  // namespace
128 
FlexfecReceiveStreamImpl(Clock * clock,Config config,RecoveredPacketReceiver * recovered_packet_receiver,RtcpRttStats * rtt_stats)129 FlexfecReceiveStreamImpl::FlexfecReceiveStreamImpl(
130     Clock* clock,
131     Config config,
132     RecoveredPacketReceiver* recovered_packet_receiver,
133     RtcpRttStats* rtt_stats)
134     : extension_map_(std::move(config.rtp.extensions)),
135       remote_ssrc_(config.rtp.remote_ssrc),
136       transport_cc_(config.rtp.transport_cc),
137       payload_type_(config.payload_type),
138       receiver_(
139           MaybeCreateFlexfecReceiver(clock, config, recovered_packet_receiver)),
140       rtp_receive_statistics_(ReceiveStatistics::Create(clock)),
141       rtp_rtcp_(CreateRtpRtcpModule(clock,
142                                     rtp_receive_statistics_.get(),
143                                     config,
144                                     rtt_stats)) {
145   RTC_LOG(LS_INFO) << "FlexfecReceiveStreamImpl: " << config.ToString();
146   RTC_DCHECK_GE(payload_type_, -1);
147 
148   packet_sequence_checker_.Detach();
149 
150   // RTCP reporting.
151   rtp_rtcp_->SetRTCPStatus(config.rtcp_mode);
152 }
153 
~FlexfecReceiveStreamImpl()154 FlexfecReceiveStreamImpl::~FlexfecReceiveStreamImpl() {
155   RTC_DLOG(LS_INFO) << "~FlexfecReceiveStreamImpl: ssrc: " << remote_ssrc_;
156 }
157 
RegisterWithTransport(RtpStreamReceiverControllerInterface * receiver_controller)158 void FlexfecReceiveStreamImpl::RegisterWithTransport(
159     RtpStreamReceiverControllerInterface* receiver_controller) {
160   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
161   RTC_DCHECK(!rtp_stream_receiver_);
162 
163   if (!receiver_)
164     return;
165 
166   // TODO(nisse): OnRtpPacket in this class delegates all real work to
167   // `receiver_`. So maybe we don't need to implement RtpPacketSinkInterface
168   // here at all, we'd then delete the OnRtpPacket method and instead register
169   // `receiver_` as the RtpPacketSinkInterface for this stream.
170   rtp_stream_receiver_ =
171       receiver_controller->CreateReceiver(remote_ssrc(), this);
172 }
173 
UnregisterFromTransport()174 void FlexfecReceiveStreamImpl::UnregisterFromTransport() {
175   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
176   rtp_stream_receiver_.reset();
177 }
178 
OnRtpPacket(const RtpPacketReceived & packet)179 void FlexfecReceiveStreamImpl::OnRtpPacket(const RtpPacketReceived& packet) {
180   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
181   if (!receiver_)
182     return;
183 
184   receiver_->OnRtpPacket(packet);
185 
186   // Do not report media packets in the RTCP RRs generated by `rtp_rtcp_`.
187   if (packet.Ssrc() == remote_ssrc()) {
188     rtp_receive_statistics_->OnRtpPacket(packet);
189   }
190 }
191 
SetPayloadType(int payload_type)192 void FlexfecReceiveStreamImpl::SetPayloadType(int payload_type) {
193   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
194   RTC_DCHECK_GE(payload_type, -1);
195   payload_type_ = payload_type;
196 }
197 
payload_type() const198 int FlexfecReceiveStreamImpl::payload_type() const {
199   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
200   return payload_type_;
201 }
202 
SetRtpExtensions(std::vector<RtpExtension> extensions)203 void FlexfecReceiveStreamImpl::SetRtpExtensions(
204     std::vector<RtpExtension> extensions) {
205   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
206   extension_map_.Reset(extensions);
207 }
208 
GetRtpExtensionMap() const209 RtpHeaderExtensionMap FlexfecReceiveStreamImpl::GetRtpExtensionMap() const {
210   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
211   return extension_map_;
212 }
213 
SetLocalSsrc(uint32_t local_ssrc)214 void FlexfecReceiveStreamImpl::SetLocalSsrc(uint32_t local_ssrc) {
215   RTC_DCHECK_RUN_ON(&packet_sequence_checker_);
216   if (local_ssrc == rtp_rtcp_->local_media_ssrc())
217     return;
218 
219   rtp_rtcp_->SetLocalSsrc(local_ssrc);
220 }
221 
222 }  // namespace webrtc
223