Re: [PATCH net-next v2 0/5] Reimplement TCP-AO using crypto library

Dmitry Safonov
2026-04-28T00:00:26Z

On Mon, 27 Apr 2026 at 23:55, Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon, 27 Apr 2026 20:09:05 +0100 Dmitry Safonov wrote:
> > I do like these numbers quite much! Yet, as I mentioned in version 1,
> > removing a fallback for other algorithms' support does not sound good
> > to me. There are two reasons:
> > - Ronald P. Bonica (the original RFC5925 author), together with Tony
> > Li do have an active RFC draft to support the additional algorithms
> > [1], potentially in addition to TCP Extended Options [2]
> > - There is at least one open-source BGP implementation (BIRD) that
> > allows using the algorithms that you are removing [3]. Without a
> > deprecation period and communication with at least known open source
> > users, it implies intentionally breaking them, which I can't agree
> > with.
> >
> > I don't feel like Naking as we don't have any customers using anything
> > other than the 3 algorithms above (and BGP implementation is
> > [unfortunately] closed-source, so that would not feel appropriate even
> > if we had such customers), yet I do feel like it's worth and
> > appropriate to express my thoughts/concerns.
>
> What do you want to happen? You are the maintainer of this code,
> you don't get so say "i don't want to nack it but also no" :)

Yeah, that's not what I meant. I see value in Eric's contribution, and
I like getting rid of tcp-sigpool. So, anything but "nack" is not "no"
:-)

> Like Eric says if there are no real users code can be deleted.
> Adding deprecation warnings upstream is quite slow, IDK if injecting
> deprecation warnings to stable has been discussed..

FWIW, I've written to bird's mailing list inviting them to this
thread; in case if they need other algorithms to be supported,
hopefully that should avoid any breakages on their side.
I'm aware that ciena and fortinet use tcp-ao too, but I'm less
concerned, as they aren't open source.

Thanks,
Dmitry