Only send UDP con req if STUNEnable is true

Because even when STUN is not enabled, the param UDPConnectionRequestAddress
will still hold IP of the listening interface which we can't reach.

lib/api-functions.ts

@@ -50,6 +50,7 @@ export async function connectionRequest(
 
   let connectionRequestUrl,
     udpConnectionRequestAddress,
+    stunEnable,
     connReqJabberId,
     username,
     password;
@@ -63,6 +64,9 @@ export async function connectionRequest(
         "InternetGatewayDevice.ManagementServer.UDPConnectionRequestAddress"
       ] || {}
     ).value || [""])[0];
+    stunEnable = ((
+      device["InternetGatewayDevice.ManagementServer.STUNEnable"] || {}
+    ).value || [""])[0];
     connReqJabberId = ((
       device["InternetGatewayDevice.ManagementServer.ConnReqJabberID"] || {}
     ).value || [""])[0];
@@ -83,6 +87,8 @@ export async function connectionRequest(
     udpConnectionRequestAddress = ((
       device["Device.ManagementServer.UDPConnectionRequestAddress"] || {}
     ).value || [""])[0];
+    stunEnable = ((device["Device.ManagementServer.STUNEnable"] || {})
+      .value || [""])[0];
     connReqJabberId = ((device["Device.ManagementServer.ConnReqJabberID"] || {})
       .value || [""])[0];
     username = ((
@@ -159,7 +165,7 @@ export async function connectionRequest(
   const debug = !!getConfig(snapshot, "cwmp.debug", {}, now, evalCallback);
 
   let udpProm;
-  if (udpConnectionRequestAddress) {
+  if (udpConnectionRequestAddress && +stunEnable) {
     udpProm = udpConnectionRequest(
       udpConnectionRequestAddress,
       authExp,