isisd: apply fast-reroute on an adjacency failure

When a adjacency falls down, the primary routes are not deleted on the
dataplane until the SPF is recomputed. Even the backup routes are
pre-installed on the dataplane, there is no fast-route optimization.

Reasons for an adjacency to come down are:
- BFD down
- Hello timer timeout
- User adjacency clear

Apply the backup route switchover for fast-reroute as soon an IS-IS
adjacency falls down before the first SPF re-computation. Pre-computed
backup routes are applied sooner.

Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/isisd/isisd.c b/isisd/isisd.c
index efea1e5d5e..b9cf336e81 100644
--- a/isisd/isisd.c
+++ b/isisd/isisd.c
@@ -3092,6 +3092,25 @@ void isis_area_verify_routes(struct isis_area *area)
 		isis_spf_verify_routes(area, area->spftree[tree]);
 }
 
+void isis_area_switchover_routes(struct isis_area *area, int family,
+				 union g_addr *nexthop_ip, ifindex_t ifindex,
+				 int level)
+{
+	int tree;
+
+	/* TODO SPFTREE_DSTSRC */
+	if (family == AF_INET)
+		tree = SPFTREE_IPV4;
+	else if (family == AF_INET6)
+		tree = SPFTREE_IPV6;
+	else
+		return;
+
+	isis_spf_switchover_routes(area, area->spftree[tree], family,
+				   nexthop_ip, ifindex, level);
+}
+
+
 static void area_resign_level(struct isis_area *area, int level)
 {
 	isis_area_invalidate_routes(area, level);