BGP: Long-lived graceful restart

The patch implements long-lived graceful restart for BGP, namely
draft-uttaro-idr-bgp-persistence-03.

1 files changed, 59 insertions, 0 deletions

diff --git a/nest/rt-table.c b/nest/rt-table.c
index 9dcbda05..036b34c4 100644
--- a/nest/rt-table.c
+++ b/nest/rt-table.c
@@ -1437,6 +1437,28 @@ rte_discard(rte *old)	/* Non-filtered route deletion, used during garbage collec
   rte_update_unlock();
 }
 
+/* Modify existing route by protocol hook, used for long-lived graceful restart */
+static inline void
+rte_modify(rte *old)
+{
+  rte_update_lock();
+
+  rte *new = old->sender->proto->rte_modify(old, rte_update_pool);
+  if (new != old)
+  {
+    if (new)
+    {
+      if (!rta_is_cached(new->attrs))
+	new->attrs = rta_lookup(new->attrs);
+      new->flags = (old->flags & ~REF_MODIFY) | REF_COW;
+    }
+
+    rte_recalculate(old->sender, old->net, new, old->attrs->src);
+  }
+
+  rte_update_unlock();
+}
+
 /* Check rtable for best route to given net whether it would be exported do p */
 int
 rt_examine(rtable *t, net_addr *a, struct proto *p, struct filter *filter)
@@ -1521,6 +1543,26 @@ rt_refresh_end(rtable *t, struct channel *c)
     rt_schedule_prune(t);
 }
 
+void
+rt_modify_stale(rtable *t, struct channel *c)
+{
+  int prune = 0;
+
+  FIB_WALK(&t->fib, net, n)
+    {
+      rte *e;
+      for (e = n->routes; e; e = e->next)
+	if ((e->sender == c) && (e->flags & REF_STALE) && !(e->flags & REF_FILTERED))
+	  {
+	    e->flags |= REF_MODIFY;
+	    prune = 1;
+	  }
+    }
+  FIB_WALK_END;
+
+  if (prune)
+    rt_schedule_prune(t);
+}
 
 /**
  * rte_dump - dump a route
@@ -1712,6 +1754,7 @@ again:
 
     rescan:
       for (e=n->routes; e; e=e->next)
+      {
 	if (e->sender->flush_active || (e->flags & REF_DISCARD))
 	  {
 	    if (limit <= 0)
@@ -1727,6 +1770,22 @@ again:
 	    goto rescan;
 	  }
 
+	if (e->flags & REF_MODIFY)
+	  {
+	    if (limit <= 0)
+	      {
+		FIB_ITERATE_PUT(fit);
+		ev_schedule(tab->rt_event);
+		return;
+	      }
+
+	    rte_modify(e);
+	    limit--;
+
+	    goto rescan;
+	  }
+      }
+
       if (!n->routes)		/* Orphaned FIB entry */
 	{
 	  FIB_ITERATE_PUT(fit);