Re: [PATCH net v2] Revert "ipv6: preserve insertion order for same-scope addresses"

Hi Íñigo,

On 03/06/2026 16:53, Íñigo Huguet wrote:

On Wed, Jun 3, 2026 at 7:46 AM Matthieu Baerts [off-list ref] wrote:

quoted

I guess it is safer not to break UAPI and not reapplying the patch,
especially when there is no clear way to know which order is taken by
the kernel.

What about clearly stating that the default order is "random", except
when an additional flag is set to sort them chronologically or the opposite?

Stating that the order is "random" implies that someone will change
the default insertion order in the future, as the documentation says
that it's not UAPI. So they'll cause the UAPI breakage that we are
trying to avoid now. Moreover, if we consider the default order
"random" and state that userspace programs must not rely on it, why
can't we change it now?

I was only suggesting "random", simply to force userspace programs to
ask for a specific order when the order matters. But also to avoid
having to describe the current order, which is different in v4 and v6
for entries of the same scope.

I know the order is not random, and even if it is confusing, I don't
think we can change it without breaking stuff.

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.