Nest: Avoid spurious announcements triggered by filtered routes

When filtered routes (enabled by 'import keep filtered' option) are
updated, they trigger announcements by rte_announce(). For regular
channels (e.g. type RA_OPTIMAL or RA_ANY) such announcement is just
ignored, but in case of RA_ACCEPTED (BGP peer with 'secondary' option)
it just reannounces the old (and still valid) best route.

The patch ensures that such no-change is ignored even for these channels.
This commit is contained in:
Ondrej Zajicek 2022-12-06 19:40:02 +01:00
parent a50d2fa65f
commit e80156d936

View file

@ -1112,7 +1112,20 @@ rte_announce(rtable *tab, uint type, net *net, rte *new, rte *old,
break; break;
case RA_ACCEPTED: case RA_ACCEPTED:
rt_notify_accepted(c, net, new, old, 0); /*
* The (new != old) condition is problematic here, as it would break
* the second usage pattern (announcement after bulk change, used in
* rt_next_hop_update_net(), which sends both new and old as NULL).
*
* But recursive next hops do not work with sorted tables anyways,
* such configuration is forbidden in BGP and not supported in
* rt_notify_accepted().
*
* The condition is needed to eliminate spurious announcements where
* both old and new routes are not valid (so they are NULL).
*/
if (new != old)
rt_notify_accepted(c, net, new, old, 0);
break; break;
case RA_MERGED: case RA_MERGED: