LibAlias in FreeBSD

From: Michael Pounov <>
Date: Fri, 27 May 2022 13:18:54 UTC
Hello Charles Mott

I wrote this mail about my work with IPFW firewall.
I am started my work over IPFW Sync driver and protocol similar like in PF firewall.
My primery goal is to do sync on NAT states in firewall router cluster. About it, I need to know when NAT driver add, readd or delete alias to be notify from libalias
I see one good approach to achieve this, but I must to asking if existing hidden drawbacks for such approach the author of libalias.

My idea is to add new member like function callback into struct libalias. If it is different from NULL, then functions which update Alias DB will call that callback for notification.
When my driver get info it will be send over network to other hosts. They must just update their Alias DBs.

What are you thinking about such approach, change and hook of the existing code?

Michael Pounov
ELWIX - Embedded LightWeight unIX -