Feature request: CARP awareness in BIRD?

[Marek Zarychta]

W dniu 2.06.2022 o 16:16, Thomas Steen Rasmussen pisze:
> Hello :)
> 
> I am using BIRD on FreeBSD and it is working okay, apart from missing 
> CARP awareness. I am wondering if anyone knows if work has been done in 
> this area already?
> 
> As you may know, CARP is a patent-free VRRP alternative originally from 
> OpenBSD. A network interface can have one or more VHIDs, each VHID can 
> be either MASTER or BACKUP. The IPs tied to a VHID are only usable when 
> the VHID is MASTER.
> 
> Currently "birdc show interfaces" shows no difference between two nodes 
> where one is CARP MASTER and the other is CARP BACKUP. The consequence 
> of this is that BIRD thinks it has a working local direct route which it 
> then tries to use, but the OS refuses, since it understands that VHID is 
> CARP BACKUP.
> 
> Ideally BIRD would understand CARP semantics so when it has a DIRECT 
> protocol it would only consume the routes from CARP MASTER VHIDs, and 
> consider the CARP BACKUP VHID IPs as unusable.
> 
> Please consider this a feature request. I am interested getting some 
> BIRD experts opinion on 1) is this a feature you would be willing to 
> include in BIRD and 2) how big a job is it?
> 
> I would be willing to pay to have it developed, although I am just 
> myself so I don't have unlimited funds.
> 
> Thanks in advance, and thank you for BIRD; even without CARP support it 
> is already awesome.
> 
Yes, it's decent piece of software and runs smooth on FreeBSD. FreeBSD 
users still believe that at some point it will better utilize new 
FreeBSD routing stack and will gain ECMP support working with this OS.

> Best regards,
> 
> Thomas Steen Rasmussen

You can solve this problem by creating two configs for BIRD and 
deploying devd(8) with simple helper shell script to trigger 
reconfiguration of BIRD when carp switches from BACKUP to MASTER or from 
MASTER to BACKUP. I have had some WiP scripts, but abandoned the idea 
since it would require doubling active BGP sessions for each peer what 
would be probably waste of resources and not acceptable in some cases.

Best regards,
-- 
Marek Zarychta
-------------- next part --------------
A non-text attachment was scrubbed...
Name: OpenPGP_signature
Type: application/pgp-signature
Size: 495 bytes
Desc: OpenPGP digital signature
URL: <http://trubka.network.cz/pipermail/bird-users/attachments/20220602/6dfa176c/attachment.sig>