Clarify Project Policy on Default Writes to NVRAM

[Christian Marangi (Ansuel)]

Il giorno sab 23 ago 2025 alle ore 13:27 Thibaut <hacks at slashdirt.org>
ha scritto:
>
>
>
> > Le 23 août 2025 à 12:55, Christian Marangi (Ansuel) <ansuelsmth at gmail.com> a écrit :
> >
> > Il giorno sab 23 ago 2025 alle ore 12:42 Goetz Goerisch
> > <ggoerisch at gmail.com> ha scritto:
> >>
> >> Thank you for the feedback.
> >>
> >>>> 3. Saving the current IPv6 prefix on the WAN port (obtained from
> >>>> the ISP) to a file. If the router reboots due to power loss, and
> >>>> the ISP changes the IPv6 prefix in the next boot, the old prefix
> >>>> can be invalidated in a Router Advertisements to prevent IPv6
> >>>> outages in the LAN due to stale addresses. This is known as "Flash
> >>>> Renumbering Workaround Across Reboot", a recommended feature by
> >>>> RFC 9096 to work around broken ISPs. This need is raised in a recent
> >>>> odhcpd development discussion [3], and is my motivation of sending
> >>>> this mail.
> >>>
> >>> I think this is the most useful feature.
> >>>
> >>> If implemented properly, it should result in a single write (per prefix assignment from the ISP, which, for sane ISPs, means only 1) which is no worse than the writes performed during firstboot: it shouldn’t be very controversial.
> >>
> >> Unfortunately at least for residential users in Germany this means
> >> typically one write per 24h. As the prefix assignments are dynamic and
> >> ISPs even today still do force reconnects every 24h.
>
> *ugh* that’s brain damaged.
>
> >> Although
> >> recommendations on best current operational practice e.g., RIPE 690
> >> [1] exist.
> >>
> >> [1] https://www.ripe.net/publications/docs/ripe-690/
> >>
> >> I would fully support that RFC9069 should be implemented for OpenWrt.
> >>
> >
> > We need to save it only on reboot so we don't need to write stuff
> > periodically every day.
> > Aside from panic conditions that we can't handle, we can attach any
> > kind of logic to be
> > done when reboot is called.
>
> As I was pointing out earlier, how many users do you think actually « reboot » their devices? (outside of OpenWrt devs, that is ;P)
>
> Panics are pretty irrelevant because the elephant in the room is it’s either going to be power loss, i.e. « let’s unplug it » (or actual power loss, even) or « it doesn’t work, let’s turn it off and on again », at which point a reboot (or more precisely a *shutdown*) handler will be totally useless.
>

Well then we should follow John idea and make it configurable. Maybe
we can enable it for eMMC by default?