rtnetlink: Migrate neighbor functions

Change-Id: I697f3d70f327f5d1d5e104dc7e4a2af528bf2b6e
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/test/test_system_queries.cpp b/test/test_system_queries.cpp
index 047d968..a79bc77 100644
--- a/test/test_system_queries.cpp
+++ b/test/test_system_queries.cpp
@@ -122,5 +122,16 @@
     EXPECT_FALSE(validateNewAddr(info, {.ifidx = 3}));
 }
 
+TEST(ValidateNewNeigh, Filtering)
+{
+    NeighborInfo info = {};
+    EXPECT_TRUE(validateNewNeigh(info, {}));
+
+    info.ifidx = 2;
+    EXPECT_TRUE(validateNewNeigh(info, {}));
+    EXPECT_TRUE(validateNewNeigh(info, {.ifidx = 2}));
+    EXPECT_FALSE(validateNewNeigh(info, {.ifidx = 3}));
+}
+
 } // namespace detail
 } // namespace phosphor::network::system