DataChannel race

out.patch

diff --git a/peerconnection.go b/peerconnection.go
index a5d50ee..5dbf46e 100644
--- a/peerconnection.go
+++ b/peerconnection.go
@@ -1313,28 +1313,6 @@ func (pc *PeerConnection) startSCTP() {

                return
        }
-
-       // DataChannels that need to be opened now that SCTP is available
-       // make a copy we may have incoming DataChannels mutating this while we open
-       pc.sctpTransport.lock.RLock()
-       dataChannels := append([]*DataChannel{}, pc.sctpTransport.dataChannels...)
-       pc.sctpTransport.lock.RUnlock()
-
-       var openedDCCount uint32
-       for _, d := range dataChannels {
-               if d.ReadyState() == DataChannelStateConnecting {
-                       err := d.open(pc.sctpTransport)
-                       if err != nil {
-                               pc.log.Warnf("failed to open data channel: %s", err)
-                               continue
-                       }
-                       openedDCCount++
-               }
-       }
-
-       pc.sctpTransport.lock.Lock()
-       pc.sctpTransport.dataChannelsOpened += openedDCCount
-       pc.sctpTransport.lock.Unlock()
 }

 func (pc *PeerConnection) handleUndeclaredSSRC(ssrc SSRC, remoteDescription *SessionDescription) (handled bool, err error) {
diff --git a/sctptransport.go b/sctptransport.go
index 41c635b..ef4b746 100644
--- a/sctptransport.go
+++ b/sctptransport.go
@@ -115,6 +115,28 @@ func (r *SCTPTransport) Start(remoteCaps SCTPCapabilities) error {
        r.sctpAssociation = sctpAssociation
        r.state = SCTPTransportStateConnected

+       // DataChannels that need to be opened now that SCTP is available
+       // make a copy we may have incoming DataChannels mutating this while we open
+       r.lock.RLock()
+       dataChannels := append([]*DataChannel{}, r.dataChannels...)
+       r.lock.RUnlock()
+
+       var openedDCCount uint32
+       for _, d := range dataChannels {
+               if d.ReadyState() == DataChannelStateConnecting {
+                       err := d.open(r)
+                       if err != nil {
+                               r.log.Warnf("failed to open data channel: %s", err)
+                               continue
+                       }
+                       openedDCCount++
+               }
+       }
+
+       r.lock.Lock()
+       r.dataChannelsOpened += openedDCCount
+       r.lock.Unlock()
+
        go r.acceptDataChannels(sctpAssociation)

        return nil