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Merge branch 'deadlock'

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This commit is contained in:
Cecylia Bocovich 2019-04-11 09:57:38 -04:00
commit 6399ef9d4f
1 changed files with 34 additions and 27 deletions
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61
proxy-go/snowflake.go
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@ -26,6 +26,9 @@ const defaultBrokerURL = "https://snowflake-broker.bamsoftware.com/"
const defaultRelayURL = "wss://snowflake.bamsoftware.com/" const defaultRelayURL = "wss://snowflake.bamsoftware.com/"
const defaultSTUNURL = "stun:stun.l.google.com:19302" const defaultSTUNURL = "stun:stun.l.google.com:19302"
const pollInterval = 5 * time.Second const pollInterval = 5 * time.Second
//amount of time after sending an SDP answer before the proxy assumes the
//client is not going to connect
const dataChannelTimeout = time.Minute
var brokerURL *url.URL var brokerURL *url.URL
var relayURL string var relayURL string
@ -259,8 +262,6 @@ func datachannelHandler(conn *webRTCConn, remoteAddr net.Addr) {
// Installs an OnDataChannel callback that creates a webRTCConn and passes it to // Installs an OnDataChannel callback that creates a webRTCConn and passes it to
// datachannelHandler. // datachannelHandler.
func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.Configuration) (*webrtc.PeerConnection, error) { func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.Configuration) (*webrtc.PeerConnection, error) {
errChan := make(chan error)
answerChan := make(chan struct{})
pc, err := webrtc.NewPeerConnection(config) pc, err := webrtc.NewPeerConnection(config)
if err != nil { if err != nil {
@ -269,9 +270,6 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.
pc.OnNegotiationNeeded = func() { pc.OnNegotiationNeeded = func() {
panic("OnNegotiationNeeded") panic("OnNegotiationNeeded")
} }
pc.OnIceComplete = func() {
answerChan <- struct{}{}
}
pc.OnDataChannel = func(dc *webrtc.DataChannel) { pc.OnDataChannel = func(dc *webrtc.DataChannel) {
log.Println("OnDataChannel") log.Println("OnDataChannel")
@ -310,31 +308,40 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc.
} }
log.Println("sdp offer successfully received.") log.Println("sdp offer successfully received.")
go func() { log.Println("Generating answer...")
log.Println("Generating answer...") answer, err := pc.CreateAnswer()
answer, err := pc.CreateAnswer() // blocking // blocks on ICE gathering. we need to add a timeout if needed
if err != nil { // not putting this in a separate go routine, because we need
errChan <- err // SetLocalDescription(answer) to be called before sendAnswer
return if err != nil {
}
err = pc.SetLocalDescription(answer)
if err != nil {
errChan <- err
return
}
}()
// Wait until answer is ready.
select {
case err = <-errChan:
pc.Destroy() pc.Destroy()
return nil, err return nil, err
case _, ok := <-answerChan:
if !ok {
pc.Destroy()
return nil, fmt.Errorf("Failed gathering ICE candidates.")
}
} }
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
}
// Set a timeout on peerconnection. If the connection state has not
// advanced to PeerConnectionStateConnected in this time,
// destroy the peer connection and return the token.
go func() {
<-time.After(dataChannelTimeout)
if pc.ConnectionState() != webrtc.PeerConnectionStateConnected {
log.Println("Timed out waiting for client to open data cannel.")
pc.Destroy()
retToken()
}
}()
return pc, nil return pc, nil
} }