Reannounce renewed UPnP mapping

cmd/syncthing/main.go

@@ -577,7 +577,9 @@ func setupUPnP(rnd rand.Source) {
 					if err == nil {
 						externalPort = r
 						l.Infoln("Created UPnP port mapping - external port", externalPort)
+						if cfg.Options.UPnPRenewal > 0 {
 							go renewUPnP(igd, rnd, port)
+						}
 						break
 					}
 				}
@@ -597,10 +599,6 @@ func setupUPnP(rnd rand.Source) {
 }
 
 func renewUPnP(igd *upnp.IGD, rnd rand.Source, port int) {
-	if cfg.Options.UPnPRenewal < 1 {
-		return
-	}
-
 	for {
 		time.Sleep(time.Duration(cfg.Options.UPnPRenewal) * time.Minute)
 
@@ -615,6 +613,7 @@ func renewUPnP(igd *upnp.IGD, rnd rand.Source, port int) {
 		if err == nil {
 			l.Infoln("Updated UPnP port mapping - external port", externalPort)
 			externalPort = r
+			discoverer.StartGlobal(cfg.Options.GlobalAnnServer, uint16(r))
 			continue
 		}
 		l.Warnln("Failed to update UPnP port mapping - externalPort", externalPort)

discover/discover.go

@@ -33,6 +33,7 @@ type Discoverer struct {
 	forcedBcastTick  chan time.Time
 	extAnnounceOK    bool
 	extAnnounceOKmut sync.Mutex
+	globalBcastStop  chan bool
 }
 
 var (
@@ -70,6 +71,11 @@ func (d *Discoverer) StartLocal() {
 }
 
 func (d *Discoverer) StartGlobal(server string, extPort uint16) {
+	if d.globalBcastStop != nil {
+		d.globalBcastStop <- true
+	} else {
+		d.globalBcastStop = make(chan bool)
+	}
 	d.extServer = server
 	d.extPort = extPort
 	go d.sendExternalAnnouncements()
@@ -230,7 +236,17 @@ func (d *Discoverer) sendExternalAnnouncements() {
 		d.extAnnounceOKmut.Unlock()
 
 		if ok {
-			time.Sleep(d.globalBcastIntv)
+			// Don't do a long sleep, listen for a stop signal, just incase
+			// the UPnP mapping has changed, and a new routine should be started.
+			for i := time.Duration(0); i < d.globalBcastIntv; i += time.Duration(1) {
+				select {
+				case <-d.globalBcastStop:
+					return
+				default:
+					time.Sleep(1 * time.Second)
+				}
+			}
+
 		} else {
 			time.Sleep(errorRetryIntv)
 		}