attempt to keep TCP listener alive if there's a temporary error (e.g. too many open files), just pause and retry later

src/multicast/multicast.go

@@ -191,7 +191,9 @@ func (m *Multicast) getAllowedInterfaces() map[string]net.Interface {
 	// Ask the system for network interfaces
 	allifaces, err := net.Interfaces()
 	if err != nil {
-		panic(err)
+		// Don't panic, since this may be from e.g. too many open files (from too much connection spam)
+		// TODO? log something
+		return nil
 	}
 	// Work out which interfaces to announce on
 	for _, iface := range allifaces {

src/yggdrasil/tcp.go

@@ -226,7 +226,13 @@ func (t *tcp) listener(l *TcpListener, listenaddr string) {
 		sock, err := l.Listener.Accept()
 		if err != nil {
 			t.links.core.log.Errorln("Failed to accept connection:", err)
-			return
+			select {
+			case <-l.stop:
+				return
+			default:
+			}
+			time.Sleep(time.Second) // So we don't busy loop
+			continue
 		}
 		t.waitgroup.Add(1)
 		options := tcpOptions{