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Fix for proxy deadlock bug

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This is a fix for the proxy-go deadlock bug (ticket #25688). The
assumption that OnIceComplete is always followed by a successful
connection where OnDataChannel has been called turns out not to occur in
practice. OnICEComplete looks like it is being deprecated in other
libraries anyway, so it's safer to just remove it.
This commit is contained in:
Cecylia Bocovich 2019-03-30 12:19:29 -04:00
parent 88f282c733
commit c28c8ca489
1 changed files with 17 additions and 27 deletions
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44
proxy-go/snowflake.go
View file

@ -259,8 +259,6 @@ func datachannelHandler(conn *webRTCConn, remoteAddr net.Addr) {
// Installs an OnDataChannel callback that creates a webRTCConn and passes it to
// datachannelHandler.
func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.Configuration) (*webrtc.PeerConnection, error) {
errChan := make(chan error)
answerChan := make(chan struct{})
pc, err := webrtc.NewPeerConnection(config)
if err != nil {
@ -269,9 +267,6 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.
pc.OnNegotiationNeeded = func() {
panic("OnNegotiationNeeded")
}
pc.OnIceComplete = func() {
answerChan <- struct{}{}
}
pc.OnDataChannel = func(dc *webrtc.DataChannel) {
log.Println("OnDataChannel")
@ -310,30 +305,25 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.
}
log.Println("sdp offer successfully received.")
go func() {
log.Println("Generating answer...")
answer, err := pc.CreateAnswer() // blocking
if err != nil {
errChan <- err
return
}
err = pc.SetLocalDescription(answer)
if err != nil {
errChan <- err
return
}
}()
// Wait until answer is ready.
select {
case err = <-errChan:
log.Println("Generating answer...")
answer, err := pc.CreateAnswer()
// blocks on ICE gathering. we need to add a timeout if needed
// not putting this in a separate go routine, because we need
// SetLocalDescription(answer) to be called before sendAnswer
if err != nil {
pc.Destroy()
return nil, err
}
if answer == nil {
pc.Destroy()
return nil, fmt.Errorf("Failed gathering ICE candidates.")
}
err = pc.SetLocalDescription(answer)
if err != nil {
pc.Destroy()
return nil, err
case _, ok := <-answerChan:
if !ok {
pc.Destroy()
return nil, fmt.Errorf("Failed gathering ICE candidates.")
}
}
return pc, nil
}