Clarify Project Policy on Default Writes to NVRAM

[Thibaut]

> 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.

Cheers,
T.