commit 1eb5c66428e0e6cce8ffc0ebf7c4ec8e65f56e30 Author: David Fifield david@bamsoftware.com Date: Tue Aug 1 15:51:34 2017 -0700
Stop writing to global opt.brokerURL variable.
This variable was being written to by multiple goroutines, overwriting the Path to either "/proxy" or "/answer" as necessary, which was racy. --- proxy-go/snowflake.go | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/proxy-go/snowflake.go b/proxy-go/snowflake.go index 5111e8e..f1dc1f0 100644 --- a/proxy-go/snowflake.go +++ b/proxy-go/snowflake.go @@ -28,7 +28,6 @@ const defaultSTUNURL = "stun:stun.l.google.com:19302" type snowflakeOptions struct { capacity uint broker string - brokerURL *url.URL stun string relay string } @@ -102,7 +101,17 @@ func genSessionID() string { return strings.TrimRight(base64.StdEncoding.EncodeToString(buf), "=") }
-func pollOffer(sid string, broker *url.URL) *webrtc.SessionDescription { +// Parses a URL with url.Parse and panics on any error. +func mustParseURL(rawurl string) *url.URL { + u, err := url.Parse(rawurl) + if err != nil { + panic(err) + } + return u +} + +func pollOffer(sid string) *webrtc.SessionDescription { + broker := mustParseURL(opt.broker) broker.Path = "/proxy" for { req, _ := http.NewRequest("POST", broker.String(), bytes.NewBuffer([]byte(sid))) @@ -126,7 +135,8 @@ func pollOffer(sid string, broker *url.URL) *webrtc.SessionDescription { } }
-func sendAnswer(sid string, broker *url.URL, pc *webrtc.PeerConnection) error { +func sendAnswer(sid string, pc *webrtc.PeerConnection) error { + broker := mustParseURL(opt.broker) broker.Path = "/answer" body := bytes.NewBuffer([]byte(pc.LocalDescription().Serialize())) req, _ := http.NewRequest("POST", broker.String(), body) @@ -272,7 +282,7 @@ func makePeerConnectionFromOffer(sdp *webrtc.SessionDescription, config *webrtc. }
func runSession(sid string) { - offer := pollOffer(sid, opt.brokerURL) + offer := pollOffer(sid) if offer == nil { log.Printf("bad offer from broker") retToken() @@ -284,7 +294,7 @@ func runSession(sid string) { retToken() return } - err = sendAnswer(sid, opt.brokerURL, pc) + err = sendAnswer(sid, pc) if err != nil { log.Printf("error sending answer to client through broker: %s", err) pc.Close() @@ -314,7 +324,7 @@ func main() { }
var err error - opt.brokerURL, err = url.Parse(opt.broker) + _, err = url.Parse(opt.broker) if err != nil { log.Fatalf("invalid broker url: %s", err) }