On 02.06.22 16:16, Thomas Steen Rasmussen wrote:
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.
Part of the problem is that FreeBSD changed their CARP implementation to
make CARP addresses part of the parent interface instead of keeping the
CARP pseudointerface OpenBSD uses (which would probably work because
it's link state goes up/down depending on the CARP state). You can
workaround missing integration of the FreeBSD CARP implementation into
bird by using FreeBSD's devd hotplug event daemon because CARP state
transitions are made available to userspace as messages on /dev/devctl
and consumed by the devd daemon (enabled by default). You can drop a
config snipped into /etc/devd/carp.conf to match the events and execute
a shell script as root to take the appropriate action e.g. run ifconfig
to get the CARP address or send a command to bird. Of course it's not as
clean as proper CARP supports, but it's flexible and responds quickly
without aggressive polling.
