Hi,
I am using BFD neighbor to config BFD sessions statically. I found that
if I add/remove BFD neighbors in bird.conf and ask bird to reload with
HUP signal, bird cannot reload the configuration correctly.
Here is the BFD config I used to test. If I start bird with this
configuration, then comment one of the neighbors and send HUP with kill
to bird, bird simply says session reconfigured without remove the
commented neighbor.
protocol bfd {
interface "*" {
passive;
};
neighbor 172.17.0.2;
neighbor 172.17.0.3;
}
After digging into the code, I found that it looks like there is a bug
in function bfd_reconfigure_neighbors. It loops to check neighbor in old
and new configuration. There is a return in the block if
(bfd_same_neighbor(nn, on)). If there is neighbor existing in both new
and old, reconfiguration might be skipped.
I tried to modify the code to make it work. And the attached patch is
the one I got. Hopefully this is the proper way to solve the issue.
Regards.
Chen.
>From 9948dea9516f015cee536d929becad389b639b78 Mon Sep 17 00:00:00 2001
From: Winston Chen <yoniorc...@gmail.com>
Date: Mon, 30 Sep 2019 22:06:01 +0800
Subject: [PATCH] BFD: Fix reload issue when neighbors change
---
proto/bfd/bfd.c | 26 +++++++++++++++++---------
1 file changed, 17 insertions(+), 9 deletions(-)
diff --git a/proto/bfd/bfd.c b/proto/bfd/bfd.c
index f774e67b..de42be82 100644
--- a/proto/bfd/bfd.c
+++ b/proto/bfd/bfd.c
@@ -825,22 +825,30 @@ bfd_reconfigure_neighbors(struct bfd_proto *p, struct bfd_config *new)
{
struct bfd_config *old = (struct bfd_config *) (p->p.cf);
struct bfd_neighbor *on, *nn;
+ int found;
WALK_LIST(on, old->neigh_list)
{
+ found = 0;
WALK_LIST(nn, new->neigh_list)
+ {
if (bfd_same_neighbor(nn, on))
{
- nn->neigh = on->neigh;
- if (nn->neigh)
- nn->neigh->data = nn;
-
- nn->req = on->req;
- nn->active = 1;
- return;
+ found = 1;
+ break;
}
-
- bfd_stop_neighbor(p, on);
+ }
+ if (found)
+ {
+ nn->neigh = on->neigh;
+ if (nn->neigh)
+ nn->neigh->data = nn;
+
+ nn->req = on->req;
+ nn->active = 1;
+ } else {
+ bfd_stop_neighbor(p, on);
+ }
}
WALK_LIST(nn, new->neigh_list)
--
2.23.0
