hotfix: add locks to make sure candidates are not send to a closed candidate channel

machinery/src/routers/mqtt/main.go

@@ -476,14 +476,9 @@ func HandleReceiveHDCandidates(mqttClient mqtt.Client, hubKey string, payload mo
 
 	if receiveHDCandidatesPayload.Timestamp != 0 {
 		if communication.CameraConnected {
+			// Register candidate channel
 			key := configuration.Config.Key + "/" + receiveHDCandidatesPayload.SessionID
-			channel := webrtc.CandidateArrays[key]
-			if channel == nil {
-				channel = make(chan string)
-				webrtc.CandidateArrays[key] = channel
-			}
-			log.Log.Info("HandleReceiveHDCandidates: " + receiveHDCandidatesPayload.Candidate)
-			channel <- receiveHDCandidatesPayload.Candidate
+			webrtc.RegisterCandidates(key, receiveHDCandidatesPayload)
 		} else {
 			log.Log.Info("HandleReceiveHDCandidates: received candidate, but camera is not connected.")
 		}

machinery/src/webrtc/main.go

@@ -87,6 +87,21 @@ func (w WebRTC) CreateOffer(sd []byte) pionWebRTC.SessionDescription {
 	return offer
 }
 
+func RegisterCandidates(key string, candidate models.ReceiveHDCandidatesPayload) {
+
+	// Set lock
+	CandidatesMutex.Lock()
+	defer CandidatesMutex.Unlock()
+
+	channel := CandidateArrays[key]
+	if channel == nil {
+		channel = make(chan string)
+		CandidateArrays[key] = channel
+	}
+	log.Log.Info("HandleReceiveHDCandidates: " + candidate.Candidate)
+	channel <- candidate.Candidate
+}
+
 func InitializeWebRTCConnection(configuration *models.Configuration, communication *models.Communication, mqttClient mqtt.Client, videoTrack *pionWebRTC.TrackLocalStaticSample, audioTrack *pionWebRTC.TrackLocalStaticSample, handshake models.RequestHDStreamPayload, candidates chan string) {
 
 	config := configuration.Config
@@ -145,6 +160,9 @@ func InitializeWebRTCConnection(configuration *models.Configuration, communicati
 
 			peerConnection.OnICEConnectionStateChange(func(connectionState pionWebRTC.ICEConnectionState) {
 				if connectionState == pionWebRTC.ICEConnectionStateDisconnected {
+					CandidatesMutex.Lock()
+					defer CandidatesMutex.Unlock()
+
 					atomic.AddInt64(&peerConnectionCount, -1)
 					peerConnections[handshake.SessionID] = nil
 					close(candidates)