Only iterates configured subnets to determine if a packet is destined for the switch

We should not check subnets learnt from route service. It is not only expensive but also incorrect.
This patch should significantly reduce the CPU usage when controller needs to reply ping to the gateway IP.

Change-Id: Ic245f5f136cf547cb50cabff4927da00e7f03666
diff --git a/app/src/test/resources/interface1.json b/app/src/test/resources/interface1.json
new file mode 100644
index 0000000..0f7123f
--- /dev/null
+++ b/app/src/test/resources/interface1.json
@@ -0,0 +1,6 @@
+[
+  {
+    "ips" : [ "10.0.1.254/24" ],
+    "vlan-untagged": 10
+  }
+]
\ No newline at end of file