ECN support

pkg/rfc8888/interceptor.go

@@ -73,7 +73,7 @@ type packet struct {
 	arrival        time.Time
 	ssrc           uint32
 	sequenceNumber uint16
-	ecn            uint8
+	ecn            rtcp.ECN
 }
 
 // BindRTCPWriter lets you modify any outgoing RTCP packets. It is called once per PeerConnection. The returned method
@@ -112,11 +112,20 @@ func (s *SenderInterceptor) BindRemoteStream(
 			return 0, nil, err
 		}
 
+		var ecn rtcp.ECN
+		if e, hasECN := attr["ECN"]; hasECN {
+			if ecnT, ok := e.(byte); ok {
+				ecn = rtcp.ECN(ecnT)
+			} else {
+				s.log.Error("ECN entry in attributes map is not of type byte")
+			}
+		}
+
 		p := packet{
 			arrival:        s.now(),
 			ssrc:           header.SSRC,
 			sequenceNumber: header.SequenceNumber,
-			ecn:            0, // ECN is not supported (yet).
+			ecn:            ecn,
 		}
 		s.packetChan <- p
 

pkg/rfc8888/recorder.go

@@ -12,7 +12,7 @@ import (
 
 type packetReport struct {
 	arrivalTime time.Time
-	ecn         uint8
+	ecn         rtcp.ECN
 }
 
 // Recorder records incoming RTP packets and their arrival times. Recorder can
@@ -30,7 +30,7 @@ func NewRecorder() *Recorder {
 }
 
 // AddPacket writes a packet to the underlying stream.
-func (r *Recorder) AddPacket(ts time.Time, ssrc uint32, seq uint16, ecn uint8) {
+func (r *Recorder) AddPacket(ts time.Time, ssrc uint32, seq uint16, ecn rtcp.ECN) {
 	stream, ok := r.streams[ssrc]
 	if !ok {
 		stream = newStreamLog(ssrc)

pkg/rfc8888/stream_log.go

@@ -32,7 +32,7 @@ func newStreamLog(ssrc uint32) *streamLog {
 	}
 }
 
-func (l *streamLog) add(ts time.Time, sequenceNumber uint16, ecn uint8) {
+func (l *streamLog) add(ts time.Time, sequenceNumber uint16, ecn rtcp.ECN) {
 	unwrappedSequenceNumber := l.sequence.Unwrap(sequenceNumber)
 	if !l.init {
 		l.init = true
@@ -68,7 +68,7 @@ func (l *streamLog) metricsAfter(reference time.Time, maxReportBlocks int64) rtc
 	gapDetected := false
 	for i := offset; i <= l.lastSequenceNumberReceived; i++ { //nolint:varnamelen // i int64
 		received := false
-		ecn := uint8(0)
+		ecn := rtcp.ECNNonECT
 		ato := uint16(0)
 		if report, ok := l.log[i]; ok {
 			received = true
@@ -77,7 +77,7 @@ func (l *streamLog) metricsAfter(reference time.Time, maxReportBlocks int64) rtc
 		}
 		metricBlocks[i-offset] = rtcp.CCFeedbackMetricBlock{
 			Received:          received,
-			ECN:               rtcp.ECN(ecn),
+			ECN:               ecn,
 			ArrivalTimeOffset: ato,
 		}
 

pkg/rfc8888/stream_log_test.go

@@ -193,7 +193,7 @@ func TestStreamLogAdd(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			sl := newStreamLog(0)
 			for _, input := range test.inputs {
-				sl.add(input.ts, input.nr, input.ecn)
+				sl.add(input.ts, input.nr, rtcp.ECN(input.ecn))
 			}
 			assert.Equal(t, test.expectedNext, sl.nextSequenceNumberToReport)
 			assert.Equal(t, test.expectedLast, sl.lastSequenceNumberReceived)
@@ -552,7 +552,7 @@ func TestStreamLogMetricsAfter(t *testing.T) {
 		t.Run(test.name, func(t *testing.T) {
 			sl := newStreamLog(0)
 			for _, input := range test.inputs {
-				sl.add(input.ts, input.nr, input.ecn)
+				sl.add(input.ts, input.nr, rtcp.ECN(input.ecn))
 			}
 
 			assert.Equal(t, test.expectedNextBefore, sl.nextSequenceNumberToReport)
@@ -572,11 +572,11 @@ func TestStreamLogMetricsAfter(t *testing.T) {
 
 func TestRemoveOldestPackets(t *testing.T) {
 	sl := newStreamLog(0)
-	sl.add(time.Time{}.Add(time.Second), 1, 0)
+	sl.add(time.Time{}.Add(time.Second), 1, rtcp.ECN(0))
 	now := time.Now().Add(10 * time.Second)
 	for i := 2; i < 16386; i++ {
 		now = now.Add(10 * time.Millisecond)
-		sl.add(now, uint16(i), 0) //nolint:gosec // G115
+		sl.add(now, uint16(i), rtcp.ECN(0)) //nolint:gosec // G115
 	}
 	metrics := sl.metricsAfter(now, maxReportsPerReportBlock)
 	assert.Equal(t, uint16(2), metrics.BeginSequence)