Implement UDP multicast handler start/stop to ensure proper lifecycle

In case FScom is not defined there is no return statement. This
moves the return outside of the ifdef to make sure a defined
value is returned.

src/mesh/NodeDB.cpp

@@ -2213,8 +2213,8 @@ bool NodeDB::restorePreferences(meshtastic_AdminMessage_BackupLocation location,
     } else if (location == meshtastic_AdminMessage_BackupLocation_SD) {
         // TODO: After more mainline SD card support
     }
-    return success;
 #endif
+    return success;
 }
 
 /// Record an error that should be reported via analytics

src/mesh/udp/UdpMulticastHandler.h

@@ -22,10 +22,14 @@
 class UdpMulticastHandler final
 {
   public:
-    UdpMulticastHandler() { udpIpAddress = IPAddress(224, 0, 0, 69); }
+    UdpMulticastHandler() : isRunning(false) { udpIpAddress = IPAddress(224, 0, 0, 69); }
 
     void start()
     {
+        if (isRunning) {
+            LOG_DEBUG("UDP multicast already running");
+            return;
+        }
         if (udp.listenMulticast(udpIpAddress, UDP_MULTICAST_DEFAUL_PORT, 64)) {
 #if defined(ARCH_NRF52) || defined(ARCH_PORTDUINO)
             LOG_DEBUG("UDP Listening on IP: %u.%u.%u.%u:%u", udpIpAddress[0], udpIpAddress[1], udpIpAddress[2], udpIpAddress[3],
@@ -34,11 +38,24 @@ class UdpMulticastHandler final
             LOG_DEBUG("UDP Listening on IP: %s", WiFi.localIP().toString().c_str());
 #endif
             udp.onPacket([this](AsyncUDPPacket packet) { onReceive(packet); });
+            isRunning = true;
         } else {
             LOG_DEBUG("Failed to listen on UDP");
         }
     }
 
+    void stop()
+    {
+        if (!isRunning) {
+            return;
+        }
+        LOG_DEBUG("Stopping UDP multicast");
+#if !defined(ARCH_NRF52)
+        udp.close();
+#endif
+        isRunning = false;
+    }
+
     void onReceive(AsyncUDPPacket packet)
     {
         size_t packetLength = packet.length();
@@ -92,5 +109,6 @@ class UdpMulticastHandler final
   private:
     IPAddress udpIpAddress;
     AsyncUDP udp;
+    bool isRunning;
 };
 #endif // HAS_UDP_MULTICAST

src/mesh/wifi/WiFiAPClient.cpp

@@ -391,6 +391,11 @@ static void WiFiEvent(WiFiEvent_t event)
         LOG_INFO("Disconnected from WiFi access point");
 #ifdef WIFI_LED
         digitalWrite(WIFI_LED, LOW);
+#endif
+#if HAS_UDP_MULTICAST
+        if (udpHandler) {
+            udpHandler->stop();
+        }
 #endif
         if (!isReconnecting) {
             WiFi.disconnect(false, true);
@@ -417,6 +422,11 @@ static void WiFiEvent(WiFiEvent_t event)
         break;
     case ARDUINO_EVENT_WIFI_STA_LOST_IP:
         LOG_INFO("Lost IP address and IP address is reset to 0");
+#if HAS_UDP_MULTICAST
+        if (udpHandler) {
+            udpHandler->stop();
+        }
+#endif
         if (!isReconnecting) {
             WiFi.disconnect(false, true);
             syslog.disable();