Network: Implement ipv6/ipv4 default gateways on EthernetInterface

Currently ipv6/ipv4 default gateway properties on SystemConfiguration
interface which will be deprecated soon.
This commit is to add Default gateway properties implementation on
EthernetInterface.

Test by:
Set ipv4/v6 default gateway properties on ethernet interface.

Signed-off-by: Ravi Teja <raviteja28031990@gmail.com>
Change-Id: I30da81d7ccf9d568a60bfdd179331b4c0d86b149
diff --git a/routing_table.hpp b/routing_table.hpp
index 6923592..8b634c6 100644
--- a/routing_table.hpp
+++ b/routing_table.hpp
@@ -8,6 +8,7 @@
 #include <list>
 #include <map>
 #include <string>
+#include <vector>
 
 namespace phosphor
 {
@@ -62,9 +63,9 @@
     /**
      * @brief gets the default v4 gateway.
      *
-     * @returns the default v4 gateway.
+     * @returns the default v4 gateway list.
      */
-    std::string getDefaultGateway() const
+    std::map<std::string, std::string> getDefaultGateway() const
     {
         return defaultGateway;
     };
@@ -72,9 +73,9 @@
     /**
      * @brief gets the default v6 gateway.
      *
-     * @returns the default v6 gateway.
+     * @returns the default v6 gateway list.
      */
-    std::string getDefaultGateway6() const
+    std::map<std::string, std::string> getDefaultGateway6() const
     {
         return defaultGateway6;
     };
@@ -94,9 +95,9 @@
      */
     void parseRoutes(const struct nlmsghdr* nlHdr);
 
-    std::string defaultGateway;  // default gateway
-    std::string defaultGateway6; // default gateway
-    Map routeList;               // List of routes
+    std::map<std::string, std::string> defaultGateway;  // default gateway list
+    std::map<std::string, std::string> defaultGateway6; // default gateway list
+    Map routeList;                                      // List of routes
 };
 
 } // namespace route