ospf6d: Fixing memory leak in ospf6_summary_add_aggr_route_and_blackhole.

Problem Statement:
=================
Memory leak in ospf6d.
2022-11-15 02:15:11,569 - ERROR: ==30108== 440 (280 direct, 160 indirect) bytes in 1 blocks are definitely lost in loss record 15 of 17
2022-11-15 02:15:11,569 - ERROR: ==30108==    at 0x4C31FAC: calloc (vg_replace_malloc.c:762)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x4E8A1BF: qcalloc (memory.c:111)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x14337A: ospf6_route_create (ospf6_route.c:462)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x11EE27: ospf6_summary_add_aggr_route_and_blackhole (ospf6_asbr.c:2779)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x11EEDA: ospf6_originate_new_aggr_lsa (ospf6_asbr.c:2816)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x120053: ospf6_handle_external_lsa_origination (ospf6_asbr.c:3659)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x12041E: ospf6_asbr_redistribute_add (ospf6_asbr.c:1547)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x14F3CC: ospf6_zebra_read_route (ospf6_zebra.c:253)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x4EC9B73: zclient_read (zclient.c:2727)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x4EB741B: thread_call (thread.c:1692)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x4E85B17: frr_run (libfrr.c:1068)
2022-11-15 02:15:11,569 - ERROR: ==30108==    by 0x119585: main (ospf6_main.c:228)
2022-11-15 02:15:11,569 - ERROR: ==30108==

RCA:
====
blackhole route was not freed before adding a new one.

Fix:
====
Added a check before allocating new route, to free the old one. Also,
added ospf6_asbr_summary_config_delete in ospf6_delet before freeing
the aggregate route.

Signed-off-by: Manoj Naragund <mnaragund@vmware.com>

1 files changed, 21 insertions, 10 deletions

diff --git a/ospf6d/ospf6_asbr.c b/ospf6d/ospf6_asbr.c
index 07061b6f5..0fd6e15ed 100644
--- a/ospf6d/ospf6_asbr.c
+++ b/ospf6d/ospf6_asbr.c
@@ -1585,7 +1585,11 @@ ospf6_asbr_summary_remove_lsa_and_route(struct ospf6 *ospf6,
 			zlog_debug(
 				"%s: Remove the blackhole route",
 				__func__);
+
 		ospf6_zebra_route_update_remove(aggr->route, ospf6);
+		if (aggr->route->route_option)
+			XFREE(MTYPE_OSPF6_EXTERNAL_INFO,
+			      aggr->route->route_option);
 		ospf6_route_delete(aggr->route);
 		aggr->route = NULL;
 	}
@@ -2736,8 +2740,13 @@ ospf6_summary_add_aggr_route_and_blackhole(struct ospf6 *ospf6,
 					   struct ospf6_external_aggr_rt *aggr)
 {
 	struct ospf6_route *rt_aggr;
+	struct ospf6_route *old_rt = NULL;
 	struct ospf6_external_info *info;
 
+	/* Check if a route is already present. */
+	if (aggr->route)
+		old_rt = aggr->route;
+
 	/* Create summary route and save it. */
 	rt_aggr = ospf6_route_create(ospf6);
 	rt_aggr->type = OSPF6_DEST_TYPE_NETWORK;
@@ -2756,6 +2765,16 @@ ospf6_summary_add_aggr_route_and_blackhole(struct ospf6 *ospf6,
 	/* Add next-hop to Null interface. */
 	ospf6_add_route_nexthop_blackhole(rt_aggr);
 
+	/* Free the old route, if any. */
+	if (old_rt) {
+		ospf6_zebra_route_update_remove(old_rt, ospf6);
+
+		if (old_rt->route_option)
+			XFREE(MTYPE_OSPF6_EXTERNAL_INFO, old_rt->route_option);
+
+		ospf6_route_delete(old_rt);
+	}
+
 	ospf6_zebra_route_update_add(rt_aggr, ospf6);
 }
 
@@ -3024,8 +3043,8 @@ static void ospf6_aggr_handle_external_info(void *data)
 	(void)ospf6_originate_type5_type7_lsas(rt, ospf6);
 }
 
-static void
-ospf6_asbr_summary_config_delete(struct ospf6 *ospf6, struct route_node *rn)
+void ospf6_asbr_summary_config_delete(struct ospf6 *ospf6,
+				      struct route_node *rn)
 {
 	struct ospf6_external_aggr_rt *aggr = rn->info;
 
@@ -3167,14 +3186,6 @@ void ospf6_external_aggregator_free(struct ospf6_external_aggr_rt *aggr)
 		hash_clean(aggr->match_extnl_hash,
 			ospf6_aggr_unlink_external_info);
 
-	if (aggr->route) {
-		if (aggr->route->route_option)
-			XFREE(MTYPE_OSPF6_EXTERNAL_INFO,
-			      aggr->route->route_option);
-
-		ospf6_route_delete(aggr->route);
-	}
-
 	if (IS_OSPF6_DEBUG_AGGR)
 		zlog_debug("%s: Release the aggregator Address(%pFX)",
 						__func__,