bgpd: Limit snmp trap for backwards state movement from established

Currently the bgp mib specifies two traps:

a) Into established state
b) transition backwards from a state

b) really is an interesting case.  It means transitioning
from say established to starting over.  It can also
mean when bgp is trying to connect and that fails and
the state transitions backwards.

Now let's imagine 500 peers with tight timers (say a data center)
and there is network trauma you have just created an inordinately
large number of traps for each peer.

Let's limit FRR to changing from the old status as Established
to something else.  This will greatly limit the trap but it
will also be something end operators are actually interested in.

I actually had several operators say they had to write special code
to ignore all the backward state transitions that they didn't care
about.

Signed-off-by: Donald Sharp <sharpd@nvidia.com>

diff --git a/bgpd/bgp_fsm.c b/bgpd/bgp_fsm.c
index 8664a7582e53501e7d2fd4bc12440d3dc75744bc..01c61615a3312c2ba5eec8b75316880d386e272e 100644 (file)
--- a/bgpd/bgp_fsm.c
+++ b/bgpd/bgp_fsm.c
@@ -1304,7 +1304,7 @@ void bgp_fsm_change_status(struct peer *peer, int status)
        peer->rtt_keepalive_rcv = 0;
 
        /* Fire backward transition hook if that's the case */
-       if (peer->ostatus > peer->status)
+       if (peer->ostatus == Established && peer->status != Established)
                hook_call(peer_backward_transition, peer);
 
        /* Save event that caused status change. */