Send GARP packet in case floating ip is associated and gateway node is updated.

Change-Id: I9aa4172bebdc25de5998b3b3123639bce7d865a0
diff --git a/apps/openstacknetworking/api/src/main/java/org/onosproject/openstacknetworking/api/InstancePortService.java b/apps/openstacknetworking/api/src/main/java/org/onosproject/openstacknetworking/api/InstancePortService.java
index d9890db..b6c99fb 100644
--- a/apps/openstacknetworking/api/src/main/java/org/onosproject/openstacknetworking/api/InstancePortService.java
+++ b/apps/openstacknetworking/api/src/main/java/org/onosproject/openstacknetworking/api/InstancePortService.java
@@ -64,6 +64,14 @@
     InstancePort instancePort(DeviceId deviceId, PortNumber portNumber);
 
     /**
+     * Returns instance ports with the given device identifier.
+     *
+     * @param deviceId device identifier
+     * @return set of instance ports; empty list if no port exists
+     */
+    Set<InstancePort> instancePort(DeviceId deviceId);
+
+    /**
      * Returns all instance ports.
      *
      * @return set of instance ports; empty list if no port exists