Rework the logic to not send double notifications in session_notification().

last_sent_errcode is now cleared late (when state changes to ESTABLISHED)
and so notifications sent in the OPEN phase would be dropped after the
first incident. Using the session state to know if sending a message is
possible seems more robust and is what session_stop() uses as well.
For now log the notification which are not sent as 'dropping' to see how
often this happens.

OK tb@

diff --git a/usr.sbin/bgpd/session.c b/usr.sbin/bgpd/session.c
index dd99479..769fa2d 100644 (file)
--- a/usr.sbin/bgpd/session.c
+++ b/usr.sbin/bgpd/session.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: session.c,v 1.468 2024/04/09 09:03:18 claudio Exp $ */
+/*     $OpenBSD: session.c,v 1.469 2024/04/10 09:05:32 claudio Exp $ */
 
 /*
  * Copyright (c) 2003, 2004, 2005 Henning Brauer <henning@openbsd.org>
@@ -1720,8 +1720,16 @@ session_notification(struct peer *p, uint8_t errcode, uint8_t subcode,
        int                      errs = 0;
        size_t                   datalen = 0;
 
-       if (p->stats.last_sent_errcode) /* some notification already sent */
+       switch (p->state) {
+       case STATE_OPENSENT:
+       case STATE_OPENCONFIRM:
+       case STATE_ESTABLISHED:
+               break;
+       default:
+               /* session not open, no need to send notification */
+               log_notification(p, errcode, subcode, ibuf, "dropping");
                return;
+       }
 
        log_notification(p, errcode, subcode, ibuf, "sending");