add default gateway redirect

ansible/scripts/switch-rules-up.sh.j2

@@ -41,4 +41,8 @@ interface_switch_redirect -A {{gw.selectionMark}} {{gw.redirectServerPort}} {{gw
 {% endif %}
 {% endfor %}
 
+{% if defaultGateway %}
+interface_switch_redirect -A 0 {{defaultGateway.redirectServerPort}} {{defaultGateway.redirectTargetPorts}}
+{% endif %}
+
 true

src/inventory.ts

@@ -437,9 +437,10 @@ class InventoryBuilder {
       routePlans,
       iptables_type: host.iptables || 'auto',
       gostConfig,
-      installGost: !!gostConfig,
+      installGost: !!gostConfig.Routes.length,
       allRedirectServerPorts,
-      relatedOcServers: host.relatedOcServers
+      relatedOcServers: host.relatedOcServers,
+      defaultGateway: availableGateways[0],
     };
   }