diff options
| author | Donatas Abraitis <donatas@opensourcerouting.org> | 2024-11-05 15:51:58 +0200 |
|---|---|---|
| committer | Donatas Abraitis <donatas@opensourcerouting.org> | 2025-02-13 20:44:11 +0200 |
| commit | 4f7e8c269dfb26ad8338aa118b6b7d504294821b (patch) | |
| tree | 97bf390bec0f15a89c81a219e2098a71973fd7c2 | |
| parent | ca307611fcee181f476f761eaef94c9a13262737 (diff) | |
bgpd: Reset BGP session only if it was a real BFD DOWN event
Without this patch we always see a double-reset, e.g.:
```
2024/11/04 12:42:43.010 BGP: [VQY9X-CQZKG] bgp_peer_bfd_update_source: address [0.0.0.0->172.18.0.3] to [172.18.0.2->172.18.0.3]
2024/11/04 12:42:43.010 BGP: [X8BD9-8RKN4] bgp_peer_bfd_update_source: interface none to eth0
2024/11/04 12:42:43.010 BFD: [MSVDW-Y8Z5Q] ptm-del-dest: deregister peer [mhop:no peer:172.18.0.3 local:0.0.0.0 vrf:default cbit:0x00 minimum-ttl:255]
2024/11/04 12:42:43.010 BFD: [NYF5K-SE3NS] ptm-del-session: [mhop:no peer:172.18.0.3 local:0.0.0.0 vrf:default] refcount=0
2024/11/04 12:42:43.010 BFD: [NW21R-MRYNT] session-delete: mhop:no peer:172.18.0.3 local:0.0.0.0 vrf:default
2024/11/04 12:42:43.010 BGP: [P3D3N-3277A] 172.18.0.3 [FSM] Timer (routeadv timer expire)
2024/11/04 12:42:43.010 BFD: [YA0Q5-C0BPV] control-packet: no session found [mhop:no peer:172.18.0.3 local:172.18.0.2 port:11]
2024/11/04 12:42:43.010 BFD: [MSVDW-Y8Z5Q] ptm-add-dest: register peer [mhop:no peer:172.18.0.3 local:172.18.0.2 vrf:default cbit:0x00 minimum-ttl:255]
2024/11/04 12:42:43.011 BFD: [PSB4R-8T1TJ] session-new: mhop:no peer:172.18.0.3 local:172.18.0.2 vrf:default ifname:eth0
2024/11/04 12:42:43.011 BGP: [Q4BCV-6FHZ5] zclient_bfd_session_update: 172.18.0.2/32 -> 172.18.0.3/32 (interface eth0) VRF default(0) (CPI bit no): Down
2024/11/04 12:42:43.011 BGP: [MKVHZ-7MS3V] bfd_session_status_update: neighbor 172.18.0.3 vrf default(0) bfd state Up -> Down
2024/11/04 12:42:43.011 BGP: [HZN6M-XRM1G] %NOTIFICATION: sent to neighbor 172.18.0.3 6/10 (Cease/BFD Down) 0 bytes
2024/11/04 12:42:43.011 BGP: [QFMSE-NPSNN] zclient_bfd_session_update: sessions updated: 1
2024/11/04 12:42:43.011 BGP: [ZWCSR-M7FG9] 172.18.0.3 [FSM] BGP_Stop (Established->Clearing), fd 22
```
Reset is due to the source address change.
With this patch, we reset the session only if it's a _REAL_ BFD down event, which
means we trigger session reset if BFD session is established earlier than BGP.
Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>
| -rw-r--r-- | bgpd/bgp_bfd.c | 23 |
1 files changed, 16 insertions, 7 deletions
diff --git a/bgpd/bgp_bfd.c b/bgpd/bgp_bfd.c index 21864cf1a6..88ffb68206 100644 --- a/bgpd/bgp_bfd.c +++ b/bgpd/bgp_bfd.c @@ -53,14 +53,23 @@ static void bfd_session_status_update(struct bfd_session_params *bsp, peer->host); return; } - peer->last_reset = PEER_DOWN_BFD_DOWN; - /* rfc9384 */ - if (BGP_IS_VALID_STATE_FOR_NOTIF(peer->connection->status)) - bgp_notify_send(peer->connection, BGP_NOTIFY_CEASE, - BGP_NOTIFY_CEASE_BFD_DOWN); - - BGP_EVENT_ADD(peer->connection, BGP_Stop); + /* Once the BFD session is UP, and later BGP session is UP, + * BFD notices that peer->su_local changed, and BFD session goes down. + * We should trigger BGP session reset if BFD session is UP + * only when BGP session is UP already. + * Otherwise, we end up resetting BGP session when BFD session is UP, + * when the source address is changed, e.g. 0.0.0.0 -> 10.0.0.1. + */ + if (bss->last_event > peer->uptime) { + peer->last_reset = PEER_DOWN_BFD_DOWN; + /* rfc9384 */ + if (BGP_IS_VALID_STATE_FOR_NOTIF(peer->connection->status)) + bgp_notify_send(peer->connection, BGP_NOTIFY_CEASE, + BGP_NOTIFY_CEASE_BFD_DOWN); + + BGP_EVENT_ADD(peer->connection, BGP_Stop); + } } if (bss->state == BSS_UP && bss->previous_state != BSS_UP && |