From bbadd4ccb6ad418fb60dc9355d411ca6ffd3400a Mon Sep 17 00:00:00 2001
From: David Zhao <david@davidzhao.com>
Date: Wed, 12 May 2021 23:40:41 -0700
Subject: [PATCH] properly cleanup downtracks on subscriber disconnect

---
 pkg/rtc/participant.go | 16 ++++++++++++++--
 pkg/rtc/transport.go   |  3 +++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/pkg/rtc/participant.go b/pkg/rtc/participant.go
index 93e595606..59b3c98f5 100644
--- a/pkg/rtc/participant.go
+++ b/pkg/rtc/participant.go
@@ -7,6 +7,7 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/pion/ion-sfu/pkg/sfu"
 	"github.com/pion/ion-sfu/pkg/twcc"
 	"github.com/pion/rtcp"
 	"github.com/pion/webrtc/v3"
@@ -367,8 +368,19 @@ func (p *ParticipantImpl) Close() error {
 		t.OnClose(nil)
 		t.RemoveAllSubscribers()
 	}
+
+	var downtracksToClose []*sfu.DownTrack
+	for _, tracks := range p.subscribedTracks {
+		for _, st := range tracks {
+			downtracksToClose = append(downtracksToClose, st.DownTrack())
+		}
+	}
 	p.lock.Unlock()
 
+	for _, dt := range downtracksToClose {
+		dt.Close()
+	}
+
 	p.updateState(livekit.ParticipantInfo_DISCONNECTED)
 	p.subscriber.pc.OnDataChannel(nil)
 	p.subscriber.pc.OnICECandidate(nil)
@@ -571,7 +583,7 @@ func (p *ParticipantImpl) GetSubscribedTracks() []types.SubscribedTrack {
 // AddSubscribedTrack adds a track to the participant's subscribed list
 func (p *ParticipantImpl) AddSubscribedTrack(pubId string, subTrack types.SubscribedTrack) {
 	logger.Debugw("added subscribedTrack", "srcParticipant", pubId,
-		"participant", p.Identity())
+		"participant", p.Identity(), "track", subTrack.ID())
 	p.lock.Lock()
 	p.subscribedTracks[pubId] = append(p.subscribedTracks[pubId], subTrack)
 	p.lock.Unlock()
@@ -580,7 +592,7 @@ func (p *ParticipantImpl) AddSubscribedTrack(pubId string, subTrack types.Subscr
 // RemoveSubscribedTrack removes a track to the participant's subscribed list
 func (p *ParticipantImpl) RemoveSubscribedTrack(pubId string, subTrack types.SubscribedTrack) {
 	logger.Debugw("removed subscribedTrack", "srcParticipant", pubId,
-		"participant", p.Identity())
+		"participant", p.Identity(), "track", subTrack.ID())
 	p.lock.Lock()
 	defer p.lock.Unlock()
 	tracks := make([]types.SubscribedTrack, 0, len(p.subscribedTracks[pubId]))
diff --git a/pkg/rtc/transport.go b/pkg/rtc/transport.go
index b1cd18369..a492750a7 100644
--- a/pkg/rtc/transport.go
+++ b/pkg/rtc/transport.go
@@ -156,6 +156,9 @@ func (t *PCTransport) CreateAndSendOffer(options *webrtc.OfferOptions) error {
 	if t.onOffer == nil {
 		return nil
 	}
+	if t.pc.ConnectionState() == webrtc.PeerConnectionStateClosed {
+		return nil
+	}
 
 	state := t.negotiationState.Load().(int)
 	// when there's an ongoing negotiation, let it finish and not disrupt its state