Do not return internal nodes to the upper layer in rn_lookup().

The limit between the radix layer and the route layer is somewhat
vague, if it exists at all.  This changes prevent rtrequest1(9) to
find and delete the root node (RNF_ROOT) when trying to delete a
non-existing default route:

# route delete 0.0.0.0
delete host 0.0.0.0
# route delete 0.0.0.0
route: writing to routing socket: No such process
delete host 0.0.0.0: not in table

Historically rn_delete() was a no-op when called with an internal
node as argument.  But there's no reason to manipulate such node.
In a better world rn_match() would contain such check, but let's
change the perfect-match function for the moment as this fixes a
bug and many dragons are lurking in there.

Fix a regression introduced by the big refactoring of r1.40 and
reported by tobias@.

ok tobias@, claudio@, pelikan@

1 files changed, 4 insertions, 1 deletions

diff --git a/sys/net/radix.c b/sys/net/radix.c
index f8eca3630cd..23e44b9c65f 100644
--- a/sys/net/radix.c
+++ b/sys/net/radix.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: radix.c,v 1.44 2015/03/04 15:53:29 claudio Exp $	*/
+/*	$OpenBSD: radix.c,v 1.45 2015/07/07 09:39:28 mpi Exp $	*/
 /*	$NetBSD: radix.c,v 1.20 2003/08/07 16:32:56 agc Exp $	*/
 
 /*
@@ -192,6 +192,9 @@ rn_lookup(void *v_arg, void *m_arg, struct radix_node_head *head)
 		while (x && x->rn_mask != netmask)
 			x = x->rn_dupedkey;
 	}
+	/* Never return internal nodes to the upper layer. */
+	if (x && (x->rn_flags & RNF_ROOT))
+		return (NULL);
 	return x;
 }