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| 1 | +// Package rfc8888 provides an interceptor that generates congestion control |
| 2 | +// feedback reports as defined by RFC 8888. |
| 3 | +package rfc8888 |
| 4 | + |
| 5 | +import ( |
| 6 | + "sync" |
| 7 | + "time" |
| 8 | + |
| 9 | + "github.com/pion/interceptor" |
| 10 | + "github.com/pion/logging" |
| 11 | + "github.com/pion/rtcp" |
| 12 | +) |
| 13 | + |
| 14 | +// TickerFactory is a factory to create new tickers |
| 15 | +type TickerFactory func(d time.Duration) ticker |
| 16 | + |
| 17 | +// SenderInterceptorFactory is a interceptor.Factory for a SenderInterceptor |
| 18 | +type SenderInterceptorFactory struct { |
| 19 | + opts []Option |
| 20 | +} |
| 21 | + |
| 22 | +// NewInterceptor constructs a new SenderInterceptor |
| 23 | +func (s *SenderInterceptorFactory) NewInterceptor(id string) (interceptor.Interceptor, error) { |
| 24 | + i := &SenderInterceptor{ |
| 25 | + NoOp: interceptor.NoOp{}, |
| 26 | + log: logging.NewDefaultLoggerFactory().NewLogger("rfc8888_interceptor"), |
| 27 | + lock: sync.Mutex{}, |
| 28 | + wg: sync.WaitGroup{}, |
| 29 | + recorder: NewRecorder(), |
| 30 | + interval: 100 * time.Millisecond, |
| 31 | + maxReportSize: 1200, |
| 32 | + packetChan: make(chan packet), |
| 33 | + newTicker: func(d time.Duration) ticker { |
| 34 | + return &timeTicker{time.NewTicker(d)} |
| 35 | + }, |
| 36 | + now: time.Now, |
| 37 | + close: make(chan struct{}), |
| 38 | + } |
| 39 | + for _, opt := range s.opts { |
| 40 | + err := opt(i) |
| 41 | + if err != nil { |
| 42 | + return nil, err |
| 43 | + } |
| 44 | + } |
| 45 | + return i, nil |
| 46 | +} |
| 47 | + |
| 48 | +// NewSenderInterceptor returns a new SenderInterceptorFactory configured with the given options. |
| 49 | +func NewSenderInterceptor(opts ...Option) (*SenderInterceptorFactory, error) { |
| 50 | + return &SenderInterceptorFactory{opts: opts}, nil |
| 51 | +} |
| 52 | + |
| 53 | +// SenderInterceptor sends congestion control feedback as specified in RFC 8888. |
| 54 | +type SenderInterceptor struct { |
| 55 | + interceptor.NoOp |
| 56 | + log logging.LeveledLogger |
| 57 | + lock sync.Mutex |
| 58 | + wg sync.WaitGroup |
| 59 | + recorder *Recorder |
| 60 | + interval time.Duration |
| 61 | + maxReportSize int64 |
| 62 | + packetChan chan packet |
| 63 | + newTicker TickerFactory |
| 64 | + now func() time.Time |
| 65 | + close chan struct{} |
| 66 | +} |
| 67 | + |
| 68 | +type packet struct { |
| 69 | + arrival time.Time |
| 70 | + ssrc uint32 |
| 71 | + sequenceNumber uint16 |
| 72 | + ecn uint8 |
| 73 | +} |
| 74 | + |
| 75 | +// BindRTCPWriter lets you modify any outgoing RTCP packets. It is called once per PeerConnection. The returned method |
| 76 | +// will be called once per packet batch. |
| 77 | +func (s *SenderInterceptor) BindRTCPWriter(writer interceptor.RTCPWriter) interceptor.RTCPWriter { |
| 78 | + s.lock.Lock() |
| 79 | + defer s.lock.Unlock() |
| 80 | + |
| 81 | + if s.isClosed() { |
| 82 | + return writer |
| 83 | + } |
| 84 | + |
| 85 | + s.wg.Add(1) |
| 86 | + go s.loop(writer) |
| 87 | + |
| 88 | + return writer |
| 89 | +} |
| 90 | + |
| 91 | +// BindRemoteStream lets you modify any incoming RTP packets. It is called once for per RemoteStream. The returned method |
| 92 | +// will be called once per rtp packet. |
| 93 | +func (s *SenderInterceptor) BindRemoteStream(info *interceptor.StreamInfo, reader interceptor.RTPReader) interceptor.RTPReader { |
| 94 | + return interceptor.RTPReaderFunc(func(b []byte, a interceptor.Attributes) (int, interceptor.Attributes, error) { |
| 95 | + i, attr, err := reader.Read(b, a) |
| 96 | + if err != nil { |
| 97 | + return 0, nil, err |
| 98 | + } |
| 99 | + |
| 100 | + if attr == nil { |
| 101 | + attr = make(interceptor.Attributes) |
| 102 | + } |
| 103 | + header, err := attr.GetRTPHeader(b[:i]) |
| 104 | + if err != nil { |
| 105 | + return 0, nil, err |
| 106 | + } |
| 107 | + |
| 108 | + p := packet{ |
| 109 | + arrival: s.now(), |
| 110 | + ssrc: header.SSRC, |
| 111 | + sequenceNumber: header.SequenceNumber, |
| 112 | + ecn: 0, // ECN is not supported (yet). |
| 113 | + } |
| 114 | + s.packetChan <- p |
| 115 | + return i, attr, nil |
| 116 | + }) |
| 117 | +} |
| 118 | + |
| 119 | +// Close closes the interceptor. |
| 120 | +func (s *SenderInterceptor) Close() error { |
| 121 | + s.log.Trace("close") |
| 122 | + defer s.wg.Wait() |
| 123 | + |
| 124 | + if !s.isClosed() { |
| 125 | + close(s.close) |
| 126 | + } |
| 127 | + |
| 128 | + return nil |
| 129 | +} |
| 130 | + |
| 131 | +func (s *SenderInterceptor) isClosed() bool { |
| 132 | + select { |
| 133 | + case <-s.close: |
| 134 | + return true |
| 135 | + default: |
| 136 | + return false |
| 137 | + } |
| 138 | +} |
| 139 | + |
| 140 | +func (s *SenderInterceptor) loop(writer interceptor.RTCPWriter) { |
| 141 | + defer s.wg.Done() |
| 142 | + |
| 143 | + select { |
| 144 | + case <-s.close: |
| 145 | + return |
| 146 | + case pkt := <-s.packetChan: |
| 147 | + s.log.Tracef("got first packet: %v", pkt) |
| 148 | + s.recorder.AddPacket(pkt.arrival, pkt.ssrc, pkt.sequenceNumber, pkt.ecn) |
| 149 | + } |
| 150 | + |
| 151 | + s.log.Trace("start loop") |
| 152 | + t := s.newTicker(s.interval) |
| 153 | + for { |
| 154 | + select { |
| 155 | + case <-s.close: |
| 156 | + t.Stop() |
| 157 | + return |
| 158 | + |
| 159 | + case pkt := <-s.packetChan: |
| 160 | + s.log.Tracef("got packet: %v", pkt) |
| 161 | + s.recorder.AddPacket(pkt.arrival, pkt.ssrc, pkt.sequenceNumber, pkt.ecn) |
| 162 | + |
| 163 | + case now := <-t.Ch(): |
| 164 | + s.log.Tracef("report triggered at %v", now) |
| 165 | + if writer == nil { |
| 166 | + s.log.Trace("no writer added, continue") |
| 167 | + continue |
| 168 | + } |
| 169 | + pkts := s.recorder.BuildReport(now, int(s.maxReportSize)) |
| 170 | + if pkts == nil { |
| 171 | + continue |
| 172 | + } |
| 173 | + s.log.Tracef("got report: %v", pkts) |
| 174 | + if _, err := writer.Write([]rtcp.Packet{pkts}, nil); err != nil { |
| 175 | + s.log.Error(err.Error()) |
| 176 | + } |
| 177 | + } |
| 178 | + } |
| 179 | +} |
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