bgpd: fix label lost when vrf loopback comes back #16403
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louis-6wind
suggested changes
Jul 17, 2024
bgpd/bgp_mplsvpn.h
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| /* should not happen */ | ||
| if (!ifp) { | ||
| if (pmsg) | ||
| *pmsg = "loopback interface not defined"; |
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loopback or vrf interface not defined
bgpd/bgp_mplsvpn.h
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| *pmsg = "loopback interface not defined"; | ||
| return 0; | ||
| } | ||
| if (!if_is_up(ifp)) { |
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if (if_is_vrf(ifp) && !if_is_up(ifp))
we do not care of the default lo being down
bgpd/bgp_mplsvpn.h
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| } | ||
| if (!if_is_up(ifp)) { | ||
| if (pmsg) | ||
| *pmsg = "loopback interface is down"; |
added 2 commits
July 17, 2024 15:41
VRF-label association drops when the VRF loopback goes down, however, it does not return once the interface is enabled again. Logs show that when VRF loopback goes down, a label drop message is sent to zebra and immediately resent label installation to zebra, trigged by "vpn_leak_postchange_all()": 2024/07/16 13:26:29 BGP: [RVJ1J-J2T22] ifp down r1-cust1 vrf id 7 2024/07/16 13:26:29 BGP: [WA2QY-06STJ] vpn_leak_zebra_vrf_label_withdraw: deleting label for vrf VRF r1-cust1 (id=7) 2024/07/16 13:26:30 BGP: [S82AC-6YAC8] vpn_leak_zebra_vrf_label_update: vrf VRF r1-cust1: afi IPv4: setting label 80 for vrf id 7 Since the interface is down, the netlink message is not send to kernel. Once the interface comes back, zebra ignore the installation assuming the label is already seen. To fix this, add a check for the interface status before attempting to reinstall the label. Signed-off-by: Loïc Sang <[email protected]>
The up/down state of the lo loopback interface does not determine the availability of the default vrf-lite. Do not update leak label at lo loopback up/down change. Fixes: b45c5cd ("bgpd: update route leak when vrf state changes") Signed-off-by: Louis Scalbert <[email protected]> Signed-off-by: Loïc Sang <[email protected]>
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VRF-label association drops when the VRF loopback goes down, however, it does not return once the interface is enabled again.
Logs show that when VRF loopback goes down, a label drop message is sent to zebra and immediately resent label installation to zebra: 2024/07/16 13:26:29 BGP: [RVJ1J-J2T22] ifp down r1-cust1 vrf id 7 2024/07/16 13:26:29 BGP: [WA2QY-06STJ] vpn_leak_zebra_vrf_label_withdraw: deleting label for vrf VRF r1-cust1 (id=7) 2024/07/16 13:26:30 BGP: [S82AC-6YAC8] vpn_leak_zebra_vrf_label_update: vrf VRF r1-cust1: afi IPv4: setting label 80 for vrf id 7
Since the interface is down, the netlink message is not send to kernel. Once the interface comes back, zebra ignore the installation assuming the label is already seen.
To fix this, add a check for the interface status before attempting to reinstall the label.