Probetest/proxy: Set multiple comma-separated default STUN URLs

This adds the BlackBerry STUN server alongside Google's. Closes #40392.

probetest/probetest.go

@@ -29,10 +29,14 @@ import (
 )
 
 const (
-	readLimit               = 100000                         //Maximum number of bytes to be read from an HTTP request
+	// Maximum number of bytes to be read from an HTTP request
-	dataChannelOpenTimeout  = 20 * time.Second               //time after which we assume proxy data channel will not open
+	readLimit = 100000
-	dataChannelCloseTimeout = 5 * time.Second                //how long to wait after the data channel has been open before closing the peer connection.
+	// Time after which we assume proxy data channel will not open
-	defaultStunUrl          = "stun:stun.l.google.com:19302" //default STUN URL
+	dataChannelOpenTimeout = 20 * time.Second
+	// How long to wait after the data channel has been open before closing the peer connection.
+	dataChannelCloseTimeout = 5 * time.Second
+	// Default STUN URL
+	defaultStunUrls = "stun:stun.l.google.com:19302,stun:stun.voip.blackberry.com:3478"
 )
 
 type ProbeHandler struct {
@@ -60,7 +64,7 @@ func makePeerConnectionFromOffer(stunURL string, sdp *webrtc.SessionDescription,
 	config := webrtc.Configuration{
 		ICEServers: []webrtc.ICEServer{
 			{
-				URLs: []string{stunURL},
+				URLs: strings.Split(stunURL, ","),
 			},
 		},
 	}
@@ -234,7 +238,7 @@ func main() {
 	flag.StringVar(&addr, "addr", ":8443", "address to listen on")
 	flag.BoolVar(&disableTLS, "disable-tls", false, "don't use HTTPS")
 	flag.BoolVar(&unsafeLogging, "unsafe-logging", false, "prevent logs from being scrubbed")
-	flag.StringVar(&stunURL, "stun", defaultStunUrl, "STUN server to use for NAT traversal")
+	flag.StringVar(&stunURL, "stun", defaultStunUrls, "STUN servers to use for NAT traversal (comma-separated)")
 	flag.Parse()
 
 	var logOutput io.Writer = os.Stderr

proxy/lib/snowflake.go

@@ -60,7 +60,7 @@ const (
 	DefaultNATProbeURL  = "https://snowflake-broker.torproject.net:8443/probe"
 	// This is rather a "DefaultDefaultRelayURL"
 	DefaultRelayURL  = "wss://snowflake.torproject.net/"
-	DefaultSTUNURL   = "stun:stun.l.google.com:19302"
+	DefaultSTUNURL   = "stun:stun.l.google.com:19302,stun:stun.voip.blackberry.com:3478"
 	DefaultProxyType = "standalone"
 )
 
@@ -123,7 +123,7 @@ type SnowflakeProxy struct {
 	// Capacity is the maximum number of clients a Snowflake will serve.
 	// Proxies with a capacity of 0 will accept an unlimited number of clients.
 	Capacity uint
-	// STUNURL is the URL of the STUN server the proxy will use
+	// STUNURL is the URLs (comma-separated) of the STUN server the proxy will use
 	STUNURL string
 	// BrokerURL is the URL of the Snowflake broker
 	BrokerURL string
@@ -757,7 +757,7 @@ func (sf *SnowflakeProxy) Start() error {
 	config = webrtc.Configuration{
 		ICEServers: []webrtc.ICEServer{
 			{
-				URLs: []string{sf.STUNURL},
+				URLs: strings.Split(sf.STUNURL, ","),
 			},
 		},
 	}

proxy/main.go

@@ -23,7 +23,7 @@ func main() {
 	pollInterval := flag.Duration("poll-interval", sf.DefaultPollInterval,
 		fmt.Sprint("how often to ask the broker for a new client. Keep in mind that asking for a client will not always result in getting one. Minumum value is ", minPollInterval, ". Valid time units are \"ms\", \"s\", \"m\", \"h\"."))
 	capacity := flag.Uint("capacity", 0, "maximum concurrent clients (default is to accept an unlimited number of clients)")
-	stunURL := flag.String("stun", sf.DefaultSTUNURL, "STUN server `URL` that this proxy will use will use to, among some other things, determine its public IP address")
+	stunURL := flag.String("stun", sf.DefaultSTUNURL, "Comma-separated STUN server `URL`s that this proxy will use will use to, among some other things, determine its public IP address")
 	logFilename := flag.String("log", "", "log `filename`. If not specified, logs will be output to stderr (console).")
 	rawBrokerURL := flag.String("broker", sf.DefaultBrokerURL, "The `URL` of the broker server that the proxy will be using to find clients")
 	unsafeLogging := flag.Bool("unsafe-logging", false, "keep IP addresses and other sensitive info in the logs")