Implement Sender and Receiver reports

Two interceptor are added to generate sender and
receiver reports from incoming and outgoing RTP and RTCP packets.

internal/test/mock_time.go

@@ -0,0 +1,26 @@
+package test
+
+import (
+	"sync"
+	"time"
+)
+
+// MockTime is a helper to replace time.Now() for testing purposes.
+type MockTime struct {
+	m      sync.RWMutex
+	curNow time.Time
+}
+
+// SetNow sets the current time.
+func (t *MockTime) SetNow(n time.Time) {
+	t.m.Lock()
+	defer t.m.Unlock()
+	t.curNow = n
+}
+
+// Now returns the current time.
+func (t *MockTime) Now() time.Time {
+	t.m.RLock()
+	defer t.m.RUnlock()
+	return t.curNow
+}

pkg/report/receiver_interceptor.go

@@ -0,0 +1,166 @@
+package report
+
+import (
+	"sync"
+	"time"
+
+	"github.com/pion/interceptor"
+	"github.com/pion/logging"
+	"github.com/pion/rtcp"
+	"github.com/pion/rtp"
+)
+
+// ReceiverInterceptor interceptor generates receiver reports.
+type ReceiverInterceptor struct {
+	interceptor.NoOp
+	interval time.Duration
+	now      func() time.Time
+	streams  sync.Map
+	log      logging.LeveledLogger
+	m        sync.Mutex
+	wg       sync.WaitGroup
+	close    chan struct{}
+}
+
+// NewReceiverInterceptor returns a new ReceiverInterceptor interceptor.
+func NewReceiverInterceptor(opts ...ReceiverOption) (*ReceiverInterceptor, error) {
+	r := &ReceiverInterceptor{
+		interval: 1 * time.Second,
+		now:      time.Now,
+		log:      logging.NewDefaultLoggerFactory().NewLogger("receiver_interceptor"),
+		close:    make(chan struct{}),
+	}
+
+	for _, opt := range opts {
+		if err := opt(r); err != nil {
+			return nil, err
+		}
+	}
+
+	return r, nil
+}
+
+func (r *ReceiverInterceptor) isClosed() bool {
+	select {
+	case <-r.close:
+		return true
+	default:
+		return false
+	}
+}
+
+// Close closes the interceptor.
+func (r *ReceiverInterceptor) Close() error {
+	defer r.wg.Wait()
+	r.m.Lock()
+	defer r.m.Unlock()
+
+	if !r.isClosed() {
+		close(r.close)
+	}
+
+	return nil
+}
+
+// BindRTCPWriter lets you modify any outgoing RTCP packets. It is called once per PeerConnection. The returned method
+// will be called once per packet batch.
+func (r *ReceiverInterceptor) BindRTCPWriter(writer interceptor.RTCPWriter) interceptor.RTCPWriter {
+	r.m.Lock()
+	defer r.m.Unlock()
+
+	if r.isClosed() {
+		return writer
+	}
+
+	r.wg.Add(1)
+
+	go r.loop(writer)
+
+	return writer
+}
+
+func (r *ReceiverInterceptor) loop(rtcpWriter interceptor.RTCPWriter) {
+	defer r.wg.Done()
+
+	ticker := time.NewTicker(r.interval)
+	for {
+		select {
+		case <-ticker.C:
+			now := r.now()
+			r.streams.Range(func(key, value interface{}) bool {
+				stream := value.(*receiverStream)
+
+				var pkts []rtcp.Packet
+
+				pkts = append(pkts, stream.generateReport(now))
+
+				if _, err := rtcpWriter.Write(pkts, interceptor.Attributes{}); err != nil {
+					r.log.Warnf("failed sending: %+v", err)
+				}
+
+				return true
+			})
+
+		case <-r.close:
+			return
+		}
+	}
+}
+
+// BindRemoteStream lets you modify any incoming RTP packets. It is called once for per RemoteStream. The returned method
+// will be called once per rtp packet.
+func (r *ReceiverInterceptor) BindRemoteStream(info *interceptor.StreamInfo, reader interceptor.RTPReader) interceptor.RTPReader {
+	stream := newReceiverStream(info.SSRC, info.ClockRate)
+	r.streams.Store(info.SSRC, stream)
+
+	return interceptor.RTPReaderFunc(func(b []byte, a interceptor.Attributes) (int, interceptor.Attributes, error) {
+		i, attr, err := reader.Read(b, a)
+		if err != nil {
+			return 0, nil, err
+		}
+
+		pkt := rtp.Packet{}
+		if err = pkt.Unmarshal(b[:i]); err != nil {
+			return 0, nil, err
+		}
+
+		stream.processRTP(r.now(), &pkt)
+
+		return i, attr, nil
+	})
+}
+
+// UnbindLocalStream is called when the Stream is removed. It can be used to clean up any data related to that track.
+func (r *ReceiverInterceptor) UnbindLocalStream(info *interceptor.StreamInfo) {
+	r.streams.Delete(info.SSRC)
+}
+
+// BindRTCPReader lets you modify any incoming RTCP packets. It is called once per sender/receiver, however this might
+// change in the future. The returned method will be called once per packet batch.
+func (r *ReceiverInterceptor) BindRTCPReader(reader interceptor.RTCPReader) interceptor.RTCPReader {
+	return interceptor.RTCPReaderFunc(func(b []byte, a interceptor.Attributes) (int, interceptor.Attributes, error) {
+		i, attr, err := reader.Read(b, a)
+		if err != nil {
+			return 0, nil, err
+		}
+
+		pkts, err := rtcp.Unmarshal(b[:i])
+		if err != nil {
+			return 0, nil, err
+		}
+
+		for _, pkt := range pkts {
+			if sr, ok := (pkt).(*rtcp.SenderReport); ok {
+				value, ok := r.streams.Load(sr.SSRC)
+				if !ok {
+					continue
+				}
+
+				stream := value.(*receiverStream)
+				stream.processSenderReport(r.now(), sr)
+			}
+		}
+
+		return i, attr, nil
+	})
+}