ospfd: install Type-7 when NSSA area is configured after redistribution

Currently, if NSSA area is configured before redistribution is enabled,
Type-7 LSA's are installed and flooded. But if NSSA area is configured
after redistribution is enabled, Type-7 LSA's are not installed.

With this change, when NSSA area is configured, schedule a task that
scans for external LSA's. If they exist, install Type-7 and flood to
all NSSA Areas.

There already was an attempt to fix this problem in 0f321812f where
ospf_asbr_nssa_redist_task() was triggered in ospf_abr_task_timer().
This turns out to be incorrect place for this operation because it's
a one-off operation needed only after "area <ID> nssa" execution. And
ospf_abr_task_timer() is a periodic operation. Triggering
ospf_asbr_nssa_redist_task() in ospf_abr_task_timer() caused a problem
that was fixed in 945eec2b6 making the problem with NSSA area
configured after redistribution actual again.

Signed-off-by: Alexander Chernavin <achernavin@netgate.com>

ospfd/ospf_abr.c

@@ -1818,7 +1818,6 @@ static int ospf_abr_task_timer(struct thread *thread)
 
 	ospf_abr_task(ospf);
 	ospf_abr_nssa_task(ospf); /* if nssa-abr, then scan Type-7 LSDB */
-	ospf_asbr_nssa_redist_task(ospf);
 
 	return 0;
 }

ospfd/ospf_asbr.c

@@ -277,10 +277,16 @@ void ospf_asbr_status_update(struct ospf *ospf, uint8_t status)
 /* If there's redistribution configured, we need to refresh external
  * LSAs in order to install Type-7 and flood to all NSSA Areas
  */
-void ospf_asbr_nssa_redist_task(struct ospf *ospf)
+static int ospf_asbr_nssa_redist_update_timer(struct thread *thread)
 {
+	struct ospf *ospf = THREAD_ARG(thread);
 	int type;
 
+	ospf->t_asbr_nssa_redist_update = NULL;
+
+	if (IS_DEBUG_OSPF_EVENT)
+		zlog_debug("Running ASBR NSSA redistribution update on timer");
+
 	for (type = 0; type < ZEBRA_ROUTE_MAX; type++) {
 		struct list *red_list;
 		struct listnode *node;
@@ -293,10 +299,22 @@ void ospf_asbr_nssa_redist_task(struct ospf *ospf)
 		for (ALL_LIST_ELEMENTS_RO(red_list, node, red))
 			ospf_external_lsa_refresh_type(ospf, type,
 						       red->instance,
-						       LSA_REFRESH_IF_CHANGED);
+						       LSA_REFRESH_FORCE);
 	}
 
 	ospf_external_lsa_refresh_default(ospf);
+
+	return 0;
+}
+
+void ospf_schedule_asbr_nssa_redist_update(struct ospf *ospf)
+{
+	if (IS_DEBUG_OSPF_EVENT)
+		zlog_debug("Scheduling ASBR NSSA redistribution update");
+
+	thread_add_timer(master, ospf_asbr_nssa_redist_update_timer, ospf,
+			 OSPF_ASBR_NSSA_REDIST_UPDATE_DELAY,
+			 &ospf->t_asbr_nssa_redist_update);
 }
 
 void ospf_redistribute_withdraw(struct ospf *ospf, uint8_t type,

ospfd/ospf_asbr.h

@@ -104,6 +104,7 @@ struct ospf_external_aggr_rt {
 };
 
 #define OSPF_ASBR_CHECK_DELAY 30
+#define OSPF_ASBR_NSSA_REDIST_UPDATE_DELAY 9
 
 extern void ospf_external_route_remove(struct ospf *, struct prefix_ipv4 *);
 extern struct external_info *ospf_external_info_new(uint8_t, unsigned short);
@@ -121,7 +122,7 @@ extern struct external_info *ospf_external_info_lookup(struct ospf *, uint8_t,
 						       unsigned short,
 						       struct prefix_ipv4 *);
 extern void ospf_asbr_status_update(struct ospf *, uint8_t);
-extern void ospf_asbr_nssa_redist_task(struct ospf *ospf);
+extern void ospf_schedule_asbr_nssa_redist_update(struct ospf *ospf);
 
 extern void ospf_redistribute_withdraw(struct ospf *, uint8_t, unsigned short);
 extern void ospf_asbr_check(void);

ospfd/ospf_vty.c

@@ -1546,6 +1546,7 @@ static int ospf_area_nssa_cmd_handler(struct vty *vty, int argc,
 	/* Flush the external LSA for the specified area */
 	ospf_flush_lsa_from_area(ospf, area_id, OSPF_AS_EXTERNAL_LSA);
 	ospf_schedule_abr_task(ospf);
+	ospf_schedule_asbr_nssa_redist_update(ospf);
 
 	return CMD_SUCCESS;
 }

ospfd/ospfd.c

@@ -791,6 +791,7 @@ static void ospf_finish_final(struct ospf *ospf)
 	OSPF_TIMER_OFF(ospf->t_maxage_walker);
 	OSPF_TIMER_OFF(ospf->t_abr_task);
 	OSPF_TIMER_OFF(ospf->t_asbr_check);
+	OSPF_TIMER_OFF(ospf->t_asbr_nssa_redist_update);
 	OSPF_TIMER_OFF(ospf->t_distribute_update);
 	OSPF_TIMER_OFF(ospf->t_lsa_refresher);
 	OSPF_TIMER_OFF(ospf->t_opaque_lsa_self);

ospfd/ospfd.h

@@ -242,6 +242,8 @@ struct ospf {
 	/* Threads. */
 	struct thread *t_abr_task;	  /* ABR task timer. */
 	struct thread *t_asbr_check;	/* ASBR check timer. */
+	struct thread *t_asbr_nssa_redist_update; /* ASBR NSSA redistribution
+						     update timer. */
 	struct thread *t_distribute_update; /* Distirbute list update timer. */
 	struct thread *t_spf_calc;	  /* SPF calculation timer. */
 	struct thread *t_ase_calc;	  /* ASE calculation timer. */