net/ipv6: Add fib6_null_entry

ip6_null_entry will stay a dst based return for lookups that fail to
match an entry.

Add a new fib6_null_entry which constitutes the root node and leafs
for fibs. Replace existing references to ip6_null_entry with the
new fib6_null_entry when dealing with FIBs.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index c29f09c..74e4e1e 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -60,7 +60,8 @@ struct netns_ipv6 {
 #endif
 	struct xt_table		*ip6table_nat;
 #endif
-	struct rt6_info         *ip6_null_entry;
+	struct rt6_info         *fib6_null_entry;
+	struct rt6_info		*ip6_null_entry;
 	struct rt6_statistics   *rt6_stats;
 	struct timer_list       ip6_fib_timer;
 	struct hlist_head       *fib_table_hash;