Re: ::1/128 and 127.0.0.1 address creation ownership

From: Olivier_Cochard-Labbé <olivier_at_freebsd.org>
Date: Mon, 22 May 2023 13:43:59 UTC
On Mon, May 22, 2023 at 12:53 PM Alexander Chernikov <melifaro@freebsd.org>
wrote:

>
> My main question here is the desired ownership model. I don’t have a
> strong opinion on whether the userland of the kernel should own loopback
> creation.
> However, I think that:
> 1) the behaviour should be consistent (either both of them created by the
> userland or both created by the kernel)
> 2) the process should be independent (e.g. adding address from one family
> shouldn’t result in adding address from the other family).
> For example, it can be either userland explicitly creates both or the
> kernel creates both on interface up, using protocol hooks).
> 3) I’m not sure SIOCSIFADDR should be (ab)used by the drivers ioctls().
> That model dates back to BSD 4.4 and doesn’t look well in presence of event
> handlers.
> Most drivers (default ethernet handler, loop, gre,disc,me,ipsec) just set
> IFF_UP there.
>
> More than happy to hear what other’s think on the issue(s)
>
>

It seems that loopback addresses are optional: I haven't found an RFC
requiring their presence, but I'd like to have more information on this.
So, the ownership of their creation seems to me good from the userland
(i.e.: rc.d): Administrators are free to configure them or not.
I agree with point 1 (consistency) and point 2 (independency), and about
point 3 I have no technical knowledge here, but the work of cleaning up and
making the proposal coherent seems good too :-)

Regards,
Olivier