Fix RTCP reader leak in DownTrack. (#4131)

When a participant is closing, RTCP readers should be cleaned up from
factory even if the participant is expected to resume. The resumed
participant will be a new participant session and peer connection(s) and
everything will be set up again.

pkg/rtc/mediatracksubscriptions.go

@@ -287,10 +287,10 @@ func (t *MediaTrackSubscriptions) closeSubscribedTrack(subTrack types.Subscribed
 	}
 
 	if isExpectedToResume {
-		dt.CloseWithFlush(false)
+		dt.CloseWithFlush(false, false)
 	} else {
 		// flushing blocks, avoid blocking when publisher removes all its subscribers
-		go dt.CloseWithFlush(true)
+		go dt.CloseWithFlush(true, true)
 	}
 }
 

pkg/rtc/subscriptionmanager.go

@@ -128,12 +128,12 @@ func (m *SubscriptionManager) Close(isExpectedToResume bool) {
 
 	if isExpectedToResume {
 		for _, dt := range downTracksToClose {
-			dt.CloseWithFlush(false)
+			dt.CloseWithFlush(false, true)
 		}
 	} else {
 		// flush blocks, so execute in parallel
 		for _, dt := range downTracksToClose {
-			go dt.CloseWithFlush(true)
+			go dt.CloseWithFlush(true, true)
 		}
 	}
 

pkg/sfu/downtrack.go

@@ -1319,7 +1319,7 @@ func (d *DownTrack) IsClosed() bool {
 }
 
 func (d *DownTrack) Close() {
-	d.CloseWithFlush(true)
+	d.CloseWithFlush(true, true)
 }
 
 // CloseWithFlush - flush used to indicate whether send blank frame to flush
@@ -1328,7 +1328,7 @@ func (d *DownTrack) Close() {
 //     set flush=true to avoid previous video shows before new stream is displayed.
 //  2. in case of session migration, participant migrate from other node, video track should
 //     be resumed with same participant, set flush=false since we don't need to flush decoder.
-func (d *DownTrack) CloseWithFlush(flush bool) {
+func (d *DownTrack) CloseWithFlush(flush bool, isEnding bool) {
 	d.bindLock.Lock()
 	if d.isClosed.Swap(true) {
 		// already closed
@@ -1364,12 +1364,12 @@ func (d *DownTrack) CloseWithFlush(flush bool) {
 	d.setBindStateLocked(bindStateUnbound)
 	d.Receiver().DeleteDownTrack(d.SubscriberID())
 
-	if d.rtcpReader != nil && flush {
+	if d.rtcpReader != nil && isEnding {
 		d.params.Logger.Debugw("downtrack close rtcp reader")
 		d.rtcpReader.Close()
 		d.rtcpReader.OnPacket(nil)
 	}
-	if d.rtcpReaderRTX != nil && flush {
+	if d.rtcpReaderRTX != nil && isEnding {
 		d.params.Logger.Debugw("downtrack close rtcp rtx reader")
 		d.rtcpReaderRTX.Close()
 		d.rtcpReaderRTX.OnPacket(nil)
@@ -1380,7 +1380,8 @@ func (d *DownTrack) CloseWithFlush(flush bool) {
 
 	d.rtpStats.Stop()
 	d.rtpStatsRTX.Stop()
-	d.params.Logger.Debugw("rtp stats",
+	d.params.Logger.Debugw(
+		"rtp stats",
 		"direction", "downstream",
 		"mime", d.Mime().String(),
 		"ssrc", d.ssrc,