Fix: do not add/remove SNAT rules when receiving FLAT vport events

Change-Id: Ib30a5d376bcb08b9a6eec595dee49b6607a8f07b

Author: gunine

apps/openstacknetworking/app/src/main/java/org/onosproject/openstacknetworking/impl/OpenstackRoutingSnatHandler.java

@@ -1459,8 +1459,14 @@ private void processGatewayCompletion(OpenstackNode osNode) {
             }
 
             if (getStatefulSnatFlag() && osNode.type() == GATEWAY) {
-                instancePortService.instancePorts().forEach(instPort ->
-                        setGatewayToInstanceDownstreamRule(osNode, instPort, true));
+                instancePortService.instancePorts().forEach(instPort -> {
+                    Type netType = osNetworkAdminService.networkType(instPort.networkId());
+
+                    if (netType == FLAT) {
+                        return;
+                    }
+                    setGatewayToInstanceDownstreamRule(osNode, instPort, true);
+                });
             }
         }
 
@@ -1470,8 +1476,15 @@ private void processGatewayRemoval(OpenstackNode osNode) {
             }
 
             if (getStatefulSnatFlag() && osNode.type() == GATEWAY) {
-                instancePortService.instancePorts().forEach(instPort ->
-                        setGatewayToInstanceDownstreamRule(osNode, instPort, false));
+                instancePortService.instancePorts().forEach(instPort -> {
+                    Type netType = osNetworkAdminService.networkType(instPort.networkId());
+
+                    if (netType == FLAT) {
+                        return;
+                    }
+
+                    setGatewayToInstanceDownstreamRule(osNode, instPort, false);
+                });
             }
         }