Add second STUN server from Cloudflare

internal/webrtc/candidates.go

@@ -18,9 +18,11 @@ type Address struct {
 	Priority uint32
 }
 
+var stuns []string
+
 func (a *Address) Host() string {
 	if a.host == "stun" {
-		ip, err := webrtc.GetCachedPublicIP()
+		ip, err := webrtc.GetCachedPublicIP(stuns...)
 		if err != nil {
 			return ""
 		}

internal/webrtc/webrtc.go

@@ -26,7 +26,7 @@ func Init() {
 
 	cfg.Mod.Listen = ":8555"
 	cfg.Mod.IceServers = []pion.ICEServer{
-		{URLs: []string{"stun:stun.l.google.com:19302"}},
+		{URLs: []string{"stun:stun.cloudflare.com:3478", "stun:stun.l.google.com:19302"}},
 	}
 
 	app.LoadConfig(&cfg)
@@ -38,6 +38,16 @@ func Init() {
 	address, network, _ := strings.Cut(cfg.Mod.Listen, "/")
 	for _, candidate := range cfg.Mod.Candidates {
 		AddCandidate(network, candidate)
+
+		if strings.HasPrefix(candidate, "stun:") && stuns == nil {
+			for _, ice := range cfg.Mod.IceServers {
+				for _, url := range ice.URLs {
+					if strings.HasPrefix(url, "stun:") {
+						stuns = append(stuns, url[5:])
+					}
+				}
+			}
+		}
 	}
 
 	var err error

pkg/webrtc/helpers.go

@@ -185,8 +185,8 @@ func LookupIP(address string) (string, error) {
 }
 
 // GetPublicIP example from https://github.com/pion/stun
-func GetPublicIP() (net.IP, error) {
-	conn, err := net.Dial("udp", "stun.l.google.com:19302")
+func GetPublicIP(address string) (net.IP, error) {
+	conn, err := net.Dial("udp", address)
 	if err != nil {
 		return nil, err
 	}
@@ -225,18 +225,19 @@ func GetPublicIP() (net.IP, error) {
 var cachedIP net.IP
 var cachedTS time.Time
 
-func GetCachedPublicIP() (net.IP, error) {
-	now := time.Now()
-	if now.After(cachedTS) {
-		newIP, err := GetPublicIP()
-		if err == nil {
-			cachedIP = newIP
-			cachedTS = now.Add(time.Minute * 5)
-		} else if cachedIP == nil {
-			return nil, err
+func GetCachedPublicIP(stuns ...string) (net.IP, error) {
+	if now := time.Now(); now.After(cachedTS) {
+		for _, addr := range stuns {
+			if ip, _ := GetPublicIP(addr); ip != nil {
+				cachedIP = ip
+				cachedTS = now.Add(time.Minute * 5)
+				return ip, nil
+			}
 		}
 	}
-
+	if cachedIP == nil {
+		return nil, errors.New("webrtc: can't get public IP")
+	}
 	return cachedIP, nil
 }
 

www/video-rtc.js

@@ -71,7 +71,7 @@ export class VideoRTC extends HTMLElement {
          */
         this.pcConfig = {
             bundlePolicy: 'max-bundle',
-            iceServers: [{urls: 'stun:stun.l.google.com:19302'}],
+            iceServers: [{urls: ['stun:stun.cloudflare.com:3478', 'stun:stun.l.google.com:19302']}],
             sdpSemantics: 'unified-plan',  // important for Chromecast 1
         };
 

www/webrtc-sync.html

@@ -21,7 +21,7 @@
 <script>
     async function PeerConnection(media) {
         const pc = new RTCPeerConnection({
-            iceServers: [{urls: 'stun:stun.l.google.com:19302'}]
+            iceServers: [{urls: ['stun:stun.cloudflare.com:3478', 'stun:stun.l.google.com:19302']}]
         });
 
         document.getElementById('video').srcObject = new MediaStream([

www/webrtc.html

@@ -21,7 +21,7 @@
 <script>
     async function PeerConnection(media) {
         const pc = new RTCPeerConnection({
-            iceServers: [{urls: 'stun:stun.l.google.com:19302'}]
+            iceServers: [{urls: ['stun:stun.cloudflare.com:3478', 'stun:stun.l.google.com:19302']}]
         });
 
         const localTracks = [];