isisd: update struct isis_sr_psid_info with nh context

Prefix-SID nexthops and backup nexthops are stored respectively in
isis_route_info->nexthops and isis_route_info->backup->nexthops.

With Flex-Algo, there are multiple Prefix-SIDs for a single prefix in
different algorithms. Each of these Prefix-SIDs performs SPF calculation
with a separate contract and sets a nexthops, so it is necessary to
store a different set nexthops for each Prefix-SID.

Add a nexthops and backup nethops list into the Prefix-SID
isis_sr_psid_info struct and use these lists instead of the  when needed

After this commit, the nexthops for each Prefix-SID is not
taken from route_info, but the nexthop set inside the
Prefix-SID is taken. This works for backup nexthops as well.

Signed-off-by: Hiroki Shirokura <hiroki.shirokura@linecorp.com>
Signed-off-by: Louis Scalbert <louis.scalbert@6wind.com>

isisd/isis_route.c

@@ -239,6 +239,9 @@ isis_route_info_new(struct prefix *prefix, struct prefix_ipv6 *src_p,
 	rinfo->cost = cost;
 	rinfo->depth = depth;
 	rinfo->sr = *sr;
+	rinfo->sr.nexthops = rinfo->nexthops;
+	rinfo->sr.nexthops_backup =
+		rinfo->backup ? rinfo->backup->nexthops : NULL;
 
 	return rinfo;
 }
@@ -489,8 +492,9 @@ static void isis_route_update(struct isis_area *area, struct prefix *prefix,
 					   route_info);
 		/* Install/reinstall Prefix-SID label. */
 		if (route_info->sr.present)
-			isis_zebra_prefix_sid_install(area, prefix, route_info,
+			isis_zebra_prefix_sid_install(area, prefix,
 						      &route_info->sr);
+
 		hook_call(isis_route_update_hook, area, prefix, route_info);
 
 		SET_FLAG(route_info->flag, ISIS_ROUTE_FLAG_ZEBRA_SYNCED);
@@ -541,10 +545,13 @@ static void _isis_route_verify_table(struct isis_area *area,
 							 src_p);
 			if (rnode_bck) {
 				rinfo->backup = rnode_bck->info;
+				rinfo->sr.nexthops_backup =
+					rinfo->backup->nexthops;
 				UNSET_FLAG(rinfo->flag,
 					   ISIS_ROUTE_FLAG_ZEBRA_SYNCED);
 			} else if (rinfo->backup) {
 				rinfo->backup = NULL;
+				rinfo->sr.nexthops_backup = NULL;
 				UNSET_FLAG(rinfo->flag,
 					   ISIS_ROUTE_FLAG_ZEBRA_SYNCED);
 			}
@@ -658,10 +665,13 @@ void isis_route_verify_merge(struct isis_area *area,
 				tables_backup[level - 1], prefix, src_p);
 			if (rnode_bck) {
 				rinfo->backup = rnode_bck->info;
+				rinfo->sr.nexthops_backup =
+					rinfo->backup->nexthops;
 				UNSET_FLAG(rinfo->flag,
 					   ISIS_ROUTE_FLAG_ZEBRA_SYNCED);
 			} else if (rinfo->backup) {
 				rinfo->backup = NULL;
+				rinfo->sr.nexthops_backup = NULL;
 				UNSET_FLAG(rinfo->flag,
 					   ISIS_ROUTE_FLAG_ZEBRA_SYNCED);
 			}
@@ -720,6 +730,7 @@ void isis_route_invalidate_table(struct isis_area *area,
 
 		if (rinfo->backup) {
 			rinfo->backup = NULL;
+			rinfo->sr.nexthops_backup = NULL;
 			/*
 			 * For now, always force routes that have backup
 			 * nexthops to be reinstalled.

isisd/isis_sr.h

@@ -63,6 +63,9 @@ struct isis_sr_psid_info {
 	bool present;
 
 	uint8_t algorithm;
+
+	struct list *nexthops;
+	struct list *nexthops_backup;
 };
 
 /* Segment Routing Local Block allocation */

isisd/isis_zebra.c

@@ -327,7 +327,6 @@ void isis_zebra_route_del_route(struct isis *isis,
  */
 void isis_zebra_prefix_sid_install(struct isis_area *area,
 				   struct prefix *prefix,
-				   struct isis_route_info *rinfo,
 				   struct isis_sr_psid_info *psid)
 {
 	struct zapi_labels zl;
@@ -342,7 +341,7 @@ void isis_zebra_prefix_sid_install(struct isis_area *area,
 	zl.local_label = psid->label;
 
 	/* Local routes don't have any nexthop and require special handling. */
-	if (list_isempty(rinfo->nexthops)) {
+	if (list_isempty(psid->nexthops)) {
 		struct zapi_nexthop *znh;
 		struct interface *ifp;
 
@@ -361,9 +360,9 @@ void isis_zebra_prefix_sid_install(struct isis_area *area,
 		znh->labels[0] = MPLS_LABEL_IMPLICIT_NULL;
 	} else {
 		/* Add backup nexthops first. */
-		if (rinfo->backup) {
+		if (psid->nexthops_backup) {
 			count = isis_zebra_add_nexthops(
-				area->isis, rinfo->backup->nexthops,
+				area->isis, psid->nexthops_backup,
 				zl.backup_nexthops, ISIS_NEXTHOP_BACKUP, true,
 				0);
 			if (count > 0) {
@@ -373,7 +372,7 @@ void isis_zebra_prefix_sid_install(struct isis_area *area,
 		}
 
 		/* Add primary nexthops. */
-		count = isis_zebra_add_nexthops(area->isis, rinfo->nexthops,
+		count = isis_zebra_add_nexthops(area->isis, psid->nexthops,
 						zl.nexthops, ISIS_NEXTHOP_MAIN,
 						true, count);
 		if (!count)

isisd/isis_zebra.h

@@ -36,7 +36,6 @@ void isis_zebra_route_del_route(struct isis *isis,
 				struct isis_route_info *route_info);
 void isis_zebra_prefix_sid_install(struct isis_area *area,
 				   struct prefix *prefix,
-				   struct isis_route_info *rinfo,
 				   struct isis_sr_psid_info *psid);
 void isis_zebra_prefix_sid_uninstall(struct isis_area *area,
 				     struct prefix *prefix,