Support adding/removing IPv4 and IPv6 addresses on interfaces

Bug: 30298058

(cherry picked from commit c296f098b63a986265ded8adf13118ba512a0fa7)

Change-Id: I4e40f4c0fe82696dc580d30e50e8c5b9fe17be88
diff --git a/server/InterfaceController.h b/server/InterfaceController.h
index 4c8057e..356cc5a 100644
--- a/server/InterfaceController.h
+++ b/server/InterfaceController.h
@@ -27,6 +27,8 @@
     static int setIPv6PrivacyExtensions(const char *interface, const int on);
     static int setIPv6NdOffload(char* interface, const int on);
     static int setMtu(const char *interface, const char *mtu);
+    static int addAddress(const char *interface, const char *addrString, int prefixLength);
+    static int delAddress(const char *interface, const char *addrString, int prefixLength);
 
 private:
     static void setAcceptRA(const char* value);