From ed97d770736b3edddb074f9ba484e915d2e83862 Mon Sep 17 00:00:00 2001
From: "Ondrej Zajicek (work)" <santiago@crfreenet.org>
Date: Sun, 17 Feb 2019 19:27:29 +0100
Subject: [PATCH] OSPF: Reset LSAs during area type change

When area is reconfigured to a different type, we need to flush LSAs as
they may not be valid (e.g. NSSA-LSA for non-NSSA area). Also, when we
have have just one OSPF area and that changes type, we could restart OSPF
as there is no state to keep anyway. That solves issue with different
handling of external routes exported to OSPF based of main area type.
---
 proto/ospf/ospf.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/proto/ospf/ospf.c b/proto/ospf/ospf.c
index 9e3e45ba..f4b46781 100644
--- a/proto/ospf/ospf.c
+++ b/proto/ospf/ospf.c
@@ -616,17 +616,25 @@ ospf_area_reconfigure(struct ospf_area *oa, struct ospf_area_config *nac)
 {
   struct ospf_proto *p = oa->po;
   struct ospf_area_config *oac = oa->ac;
-  struct ospf_iface *ifa;
+  struct ospf_iface *ifa, *ifx;
 
   oa->ac = nac;
   oa->options = nac->type | ospf_opts(p);
 
   if (nac->type != oac->type)
   {
-    /* Force restart of area interfaces */
-    WALK_LIST(ifa, p->iface_list)
+    log(L_INFO "%s: Restarting area %R", p->p.name, oa->areaid);
+
+    /* Remove area interfaces, will be re-added later */
+    WALK_LIST_DELSAFE(ifa, ifx, p->iface_list)
       if (ifa->oa == oa)
-	ifa->marked = 2;
+      {
+	ospf_iface_shutdown(ifa);
+	ospf_iface_remove(ifa);
+      }
+
+    /* Flush area LSAs */
+    ospf_flush_area(p, oa->areaid);
   }
 
   /* Handle net_list */
@@ -656,7 +664,7 @@ ospf_reconfigure(struct proto *P, struct proto_config *CF)
   struct ospf_proto *p = (struct ospf_proto *) P;
   struct ospf_config *old = (struct ospf_config *) (P->cf);
   struct ospf_config *new = (struct ospf_config *) CF;
-  struct ospf_area_config *nac;
+  struct ospf_area_config *oac, *nac;
   struct ospf_area *oa, *oax;
   struct ospf_iface *ifa, *ifx;
   struct ospf_iface_patt *ip;
@@ -676,6 +684,15 @@ ospf_reconfigure(struct proto *P, struct proto_config *CF)
   if (old->abr != new->abr)
     return 0;
 
+  if (p->areano == 1)
+  {
+    oac = HEAD(old->area_list);
+    nac = HEAD(new->area_list);
+
+    if (oac->type != nac->type)
+      return 0;
+  }
+
   if (old->vpn_pe != new->vpn_pe)
     return 0;
 
@@ -691,7 +708,7 @@ ospf_reconfigure(struct proto *P, struct proto_config *CF)
   p->ecmp = new->ecmp;
   p->tick = new->tick;
   p->disp_timer->recurrent = p->tick S;
-  tm_start(p->disp_timer, 100 MS);
+  tm_start(p->disp_timer, 10 MS);
 
   /* Mark all areas and ifaces */
   WALK_LIST(oa, p->area_list)