Merge pull request #11183 from opensourcerouting/feature/handle_bgp_gr_notification

[mirror_frr.git] / bgpd / bgp_packet.c

diff --git a/bgpd/bgp_packet.c b/bgpd/bgp_packet.c
index 459b4d5e3f951d50a9127e84402dae7c9c507ec6..cacc4995fcead0dce63a5f474b07d371080b154a 100644 (file)
--- a/bgpd/bgp_packet.c
+++ b/bgpd/bgp_packet.c
@@ -748,6 +748,13 @@ struct bgp_notify bgp_notify_decapsulate_hard_reset(struct bgp_notify *notify)
        return bn;
 }
 
+/* Check if Graceful-Restart N-bit is exchanged */
+bool bgp_has_graceful_restart_notification(struct peer *peer)
+{
+       return CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_RCV) &&
+              CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_ADV);
+}
+
 /*
  * Check if to send BGP CEASE Notification/Hard Reset?
  */
@@ -757,8 +764,7 @@ bool bgp_notify_send_hard_reset(struct peer *peer, uint8_t code,
        /* When the "N" bit has been exchanged, a Hard Reset message is used to
         * indicate to the peer that the session is to be fully terminated.
         */
-       if (!CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_RCV) ||
-           !CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_ADV))
+       if (!bgp_has_graceful_restart_notification(peer))
                return false;
 
        /*
@@ -797,8 +803,7 @@ bool bgp_notify_received_hard_reset(struct peer *peer, uint8_t code,
        /* When the "N" bit has been exchanged, a Hard Reset message is used to
         * indicate to the peer that the session is to be fully terminated.
         */
-       if (!CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_RCV) ||
-           !CHECK_FLAG(peer->cap, PEER_CAP_GRACEFUL_RESTART_N_BIT_ADV))
+       if (!bgp_has_graceful_restart_notification(peer))
                return false;
 
        if (code == BGP_NOTIFY_CEASE && subcode == BGP_NOTIFY_CEASE_HARD_RESET)
@@ -2094,6 +2099,13 @@ static int bgp_notify_receive(struct peer *peer, bgp_size_t size)
            inner.subcode == BGP_NOTIFY_OPEN_UNSUP_PARAM)
                UNSET_FLAG(peer->sflags, PEER_STATUS_CAPABILITY_OPEN);
 
+       /* If Graceful-Restart N-bit (Notification) is exchanged,
+        * and it's not a Hard Reset, let's retain the routes.
+        */
+       if (bgp_has_graceful_restart_notification(peer) && !hard_reset &&
+           CHECK_FLAG(peer->sflags, PEER_STATUS_NSF_MODE))
+               SET_FLAG(peer->sflags, PEER_STATUS_NSF_WAIT);
+
        bgp_peer_gr_flags_update(peer);
        BGP_GR_ROUTER_DETECT_AND_SEND_CAPABILITY_TO_ZEBRA(peer->bgp,
                                                          peer->bgp->peer);