zebra: Add a base node for the zebra vrf tables

Add a default route_node for our routing tables.  This will allow us
to know that we can hang data off the default route for processing.

We will be hanging the nexthop tracking data structures off the rib_dest_t
so that we can know which nexthops we need to handle.  Effectively
nexthops that we are tracking that are unresolved will be stored on the
default route.  When something changes in the rib tree we can
work up the rn->parent pointer checking for nexthops we need to re-evaluate.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/zebra/zebra_rib.c b/zebra/zebra_rib.c
index 5d98d61645..6b837e4e36 100644
--- a/zebra/zebra_rib.c
+++ b/zebra/zebra_rib.c
@@ -1205,6 +1205,16 @@ static int rib_can_delete_dest(rib_dest_t *dest)
 	}
 
 	/*
+	 * Unresolved rnh's are stored on the default route's list
+	 *
+	 * dest->rnode can also be the source prefix node in an
+	 * ipv6 sourcedest table.  Fortunately the prefix of a
+	 * source prefix node can never be the default prefix.
+	 */
+	if (is_default_prefix(&dest->rnode->p))
+		return 0;
+
+	/*
 	 * Don't delete the dest if we have to update the FPM about this
 	 * prefix.
 	 */