neighbor: Rework getCurrentNeighbors

Now allows filtering out undesirable neighbors before passing them in
them back.

Change-Id: I7f6484586ffbc8a875c7e4342d3180746f2e55e5
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/ethernet_interface.hpp b/ethernet_interface.hpp
index 5551950..3935390 100644
--- a/ethernet_interface.hpp
+++ b/ethernet_interface.hpp
@@ -127,6 +127,10 @@
      */
     void createStaticNeighborObjects();
 
+    /* @brief Gets the index of the interface on the system
+     */
+    unsigned ifIndex() const;
+
     /* @brief Gets all the ip addresses.
      * @returns the list of ipaddress.
      */