net: do not advertise address where nobody is listening

If the bitcoind starts when listen=0 but listenonion=1, the daemon will
advertise its onion address but nothing is listening for it.

This update will enforce listenonion=0 when the listen is 0.

fixes bitcoin#20657

Author: Jadi

src/init.cpp

@@ -1047,6 +1047,11 @@ bool AppInitParameterInteraction(const ArgsManager& args)
         return InitError(Untranslated("Cannot set -bind or -whitebind together with -listen=0"));
     }
 
+    // if listen=0, then disallow listenonion=1
+    if (!args.GetBoolArg("-listen", DEFAULT_LISTEN) && args.GetBoolArg("-listenonion", DEFAULT_LISTEN_ONION)) {
+        return InitError(Untranslated("Cannot set -listen=0 together with -listenonion=1"));
+    }
+
     // Make sure enough file descriptors are available
     int nBind = std::max(nUserBind, size_t(1));
     nUserMaxConnections = args.GetArg("-maxconnections", DEFAULT_MAX_PEER_CONNECTIONS);