Fix ORTC accept datachannel sctpTransport is nil

datachannel.go

@@ -65,7 +65,7 @@ type DataChannel struct {
 // This constructor is part of the ORTC API. It is not
 // meant to be used together with the basic WebRTC API.
 func (api *API) NewDataChannel(transport *SCTPTransport, params *DataChannelParameters) (*DataChannel, error) {
-	d, err := api.newDataChannel(params, api.settingEngine.LoggerFactory.NewLogger("ortc"))
+	d, err := api.newDataChannel(params, nil, api.settingEngine.LoggerFactory.NewLogger("ortc"))
 	if err != nil {
 		return nil, err
 	}
@@ -80,13 +80,14 @@ func (api *API) NewDataChannel(transport *SCTPTransport, params *DataChannelPara
 
 // newDataChannel is an internal constructor for the data channel used to
 // create the DataChannel object before the networking is set up.
-func (api *API) newDataChannel(params *DataChannelParameters, log logging.LeveledLogger) (*DataChannel, error) {
+func (api *API) newDataChannel(params *DataChannelParameters, sctpTransport *SCTPTransport, log logging.LeveledLogger) (*DataChannel, error) {
 	// https://w3c.github.io/webrtc-pc/#peer-to-peer-data-api (Step #5)
 	if len(params.Label) > 65535 {
 		return nil, &rtcerr.TypeError{Err: ErrStringSizeLimit}
 	}
 
 	d := &DataChannel{
+		sctpTransport:     sctpTransport,
 		statsID:           fmt.Sprintf("DataChannel-%d", time.Now().UnixNano()),
 		label:             params.Label,
 		protocol:          params.Protocol,

peerconnection.go

@@ -1950,7 +1950,7 @@ func (pc *PeerConnection) CreateDataChannel(label string, options *DataChannelIn
 		}
 	}
 
-	d, err := pc.api.newDataChannel(params, pc.log)
+	d, err := pc.api.newDataChannel(params, nil, pc.log)
 	if err != nil {
 		return nil, err
 	}

sctptransport.go

@@ -224,7 +224,7 @@ ACCEPT:
 			Ordered:           ordered,
 			MaxPacketLifeTime: maxPacketLifeTime,
 			MaxRetransmits:    maxRetransmits,
-		}, r.api.settingEngine.LoggerFactory.NewLogger("ortc"))
+		}, nil, r.api.settingEngine.LoggerFactory.NewLogger("ortc"))
 		if err != nil {
 			r.log.Errorf("Failed to accept data channel: %v", err)
 			r.onError(err)