Method SetRemoteDescription

peerconnection.go:1180–1386

SetRemoteDescription sets the SessionDescription of the remote peer nolint:gocognit,gocyclo,cyclop,maintidx

(desc SessionDescription)

//
//nolint:gocognit,gocyclo,cyclop,maintidx
func (pc *PeerConnection) SetRemoteDescription(desc SessionDescription) error {
	if pc.isClosed.Load() {
		return &rtcerr.InvalidStateError{Err: ErrConnectionClosed}
	}

	isRenegotiation := pc.currentRemoteDescription != nil

	if _, err := desc.Unmarshal(); err != nil {
		return err
	}

	if err := pc.setDescription(&desc, stateChangeOpSetRemote); err != nil {
		return err
	}

	if err := pc.api.mediaEngine.updateFromRemoteDescription(*desc.parsed); err != nil {
		return err
	}

	canTrickle := hasICETrickleOption(desc.parsed)
	pc.mu.Lock()
	switch desc.Type {
	case SDPTypeOffer, SDPTypeAnswer, SDPTypePranswer:
		if canTrickle {
			pc.canTrickleICECandidates = ICETrickleCapabilitySupported
		} else {
			pc.canTrickleICECandidates = ICETrickleCapabilityUnsupported
		}
	default:
		pc.canTrickleICECandidates = ICETrickleCapabilityUnknown
	}
	pc.mu.Unlock()

	// Disable RTX/FEC on RTPSenders if the remote didn't support it
	for _, sender := range pc.GetSenders() {
		sender.configureRTXAndFEC()
	}

	var transceiver *RTPTransceiver
	localTransceivers := append([]*RTPTransceiver{}, pc.GetTransceivers()...)
	detectedPlanB := descriptionIsPlanB(pc.RemoteDescription(), pc.log)
	if pc.configuration.SDPSemantics != SDPSemanticsUnifiedPlan {
		detectedPlanB = descriptionPossiblyPlanB(pc.RemoteDescription())
	}

	weOffer := desc.Type == SDPTypeAnswer

	if !weOffer && !detectedPlanB { //nolint:nestif
		for _, media := range pc.RemoteDescription().parsed.MediaDescriptions {
			midValue := getMidValue(media)
			if midValue == "" {
				return errPeerConnRemoteDescriptionWithoutMidValue
			}

			if media.MediaName.Media == mediaSectionApplication {
				continue
			}