LLDP Causes Constant Interface Flapping and VRRP Log Spam

[amuckart]

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Describe the bug
When LLDPD is running, FRR records a 'link-up' event approximately every second. This causes VRRP to try and start, and spam the log file with errors.

• [ X ] Did you check if this is a duplicate issue?
• Did you test it on the latest FRRouting/frr master branch?

To Reproduce

Configure lldpd

configure system interface description
configure system bond-slave-src-mac-type real
configure lldp agent-type nearest-bridge
configure lldp portidsubtype ifname
configure lldp status rx-and-tx

Start FRR with a basic or even empty configuration

Repeatedly run show interfaces and watch the 'Link up:' count increment on physical Ethernet links which are running LLDP.

Expected behavior
LLDP updates should not cause a link-up event in FRR.

Screenshots
Links bouncing:

root@rtr1:~# while true; do echo; vtysh -c 'show int' | grep 'Link ' | grep -v ' 0 '; sleep 1; done

  Link ups:     117    last: 2023/11/24 09:21:54.98
  Link ups:     117    last: 2023/11/24 09:21:54.98
  Link ups:     117    last: 2023/11/24 09:21:54.98

  Link ups:     119    last: 2023/11/24 09:21:56.35
  Link ups:     119    last: 2023/11/24 09:21:56.35
  Link ups:     119    last: 2023/11/24 09:21:56.36

  Link ups:     120    last: 2023/11/24 09:21:57.36
  Link ups:     120    last: 2023/11/24 09:21:57.36
  Link ups:     120    last: 2023/11/24 09:21:57.36

  Link ups:     121    last: 2023/11/24 09:21:58.37
  Link ups:     121    last: 2023/11/24 09:21:58.37
  Link ups:     121    last: 2023/11/24 09:21:58.37

Log messages

2023-11-24T10:14:10.149575+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv4] Refusing to start Virtual Router: Already running
2023-11-24T10:14:10.149938+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv6] Refusing to start Virtual Router: No VRRP interface
2023-11-24T10:14:11.154162+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 2] [IPv4] Refusing to start Virtual Router: Already running
2023-11-24T10:14:11.154707+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 2] [IPv6] Refusing to start Virtual Router: No VRRP interface
2023-11-24T10:14:11.155104+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv4] Refusing to start Virtual Router: Already running
2023-11-24T10:14:11.155481+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv6] Refusing to start Virtual Router: No VRRP interface
2023-11-24T10:14:12.158091+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 2] [IPv4] Refusing to start Virtual Router: Already running
2023-11-24T10:14:12.158871+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 2] [IPv6] Refusing to start Virtual Router: No VRRP interface
2023-11-24T10:14:12.159354+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv4] Refusing to start Virtual Router: Already running
2023-11-24T10:14:12.159902+13:00 rtr1 vrrpd[38064]: [P485H-A79BW] [CORE] [VRID 1] [IPv6] Refusing to start Virtual Router: No VRRP interface

Versions

• OS Version: Ubuntu 22.04

• Kernel: 5.15.0

• FRR Version: 9.0.1 (also tried 8.5.3, same result)
• LLDPD version 1.0.17

Additional context

[donaldsharp]

I would say that this is not something that is going to be fixed in FRR. Issue a ip monitor link and you should be seeing constant link changes coming in. LLDPD ( whatever this is ) should be looked at. FRR is only responding to system events that are being sent to it in this case

[amuckart]

Thank you, you are right. Using systemd for lldp doesn't have this problem.