ospf6d: fix ospf6 asbr crash

Durig ospf6 instance cleanup all border routers
are removed from the db then external LSAs removal
from DB is triggered. During the time, external route
path would not be valid as brouters along with its
rechability have vanished.
For a given external route removal check if no more
paths available simple remove the route from route db.

Ticket:CM-20669
Testing Done:
Bring up ASBR configuration with ECMP paths to a route.
Bring down the ospf6 instance and validate route is removed
from the DB.

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>

1 files changed, 28 insertions, 18 deletions

diff --git a/ospf6d/ospf6_asbr.c b/ospf6d/ospf6_asbr.c
index 1b46b9c68..0fe0cada3 100644
--- a/ospf6d/ospf6_asbr.c
+++ b/ospf6d/ospf6_asbr.c
@@ -685,8 +685,9 @@ void ospf6_asbr_lsa_remove(struct ospf6_lsa *lsa,
 				if (IS_OSPF6_DEBUG_EXAMIN(AS_EXTERNAL)) {
 					prefix2str(&prefix, buf, sizeof(buf));
 					zlog_debug(
-						"%s: route %s path found with nh %u to remove.",
+						"%s: route %s path found with cost %u nh %u to remove.",
 						__PRETTY_FUNCTION__, buf,
+						route->path.cost,
 						listcount(o_path->nh_list));
 				}
 
@@ -738,28 +739,37 @@ void ospf6_asbr_lsa_remove(struct ospf6_lsa *lsa,
 						listcount(route->nh_list));
 				}
 
-				/* Update RIB/FIB with effective nh_list */
-				if (ospf6->route_table->hook_add)
-					(*ospf6->route_table->hook_add)(route);
+				if (listcount(route->paths)) {
+					/* Update RIB/FIB with effective
+					 * nh_list
+					 */
+					if (ospf6->route_table->hook_add)
+						(*ospf6->route_table->hook_add)
+						(route);
 
-				/* route's primary path is similar to LSA,
-				 * replace route's primary path with
-				 * route's paths list head.
-				 */
-				if (route->path.origin.id == lsa->header->id
-				    && route->path.origin.adv_router
-					       == lsa->header->adv_router) {
-					struct ospf6_path *h_path;
+					/* route's primary path is similar
+					 * to LSA, replace route's primary
+					 * path with route's paths list head.
+					 */
+					if ((route->path.origin.id ==
+					    lsa->header->id) &&
+					    (route->path.origin.adv_router
+						 == lsa->header->adv_router)) {
+						struct ospf6_path *h_path;
 
-					h_path = (struct ospf6_path *)
+						h_path = (struct ospf6_path *)
 						listgetdata(
 							listhead(route->paths));
-					route->path.origin.type =
-						h_path->origin.type;
-					route->path.origin.id =
-						h_path->origin.id;
-					route->path.origin.adv_router =
+						route->path.origin.type =
+							h_path->origin.type;
+						route->path.origin.id =
+							h_path->origin.id;
+						route->path.origin.adv_router =
 						h_path->origin.adv_router;
+					}
+				} else {
+					ospf6_route_remove(route,
+							   ospf6->route_table);
 				}
 			}
 			continue;