Re: [PATCH net-next] ipv6: don't generate link-local addr in random or privacy mode

From: Maciej Żenczykowski
Date: Wed Nov 17 2021 - 04:51:15 EST

> Can't 4 be the same as 3? The same netlink message can configure both
> the addr_gen_mode and the token, no?
> It seems to me that the following should work, and would be much simpler.
> 1. Bring the interface down. All addresses are deleted.
> 2. Send a netlink request to set addr_gen_mode RANDOM_LL_TOKEN or
> PRIVACY_LL_TOKEN and set the token.
> 3. Bring the interface up. Autoconf runs. The link-local address is
> generated from the token. An RS is sent. When the RA is received, the
> global address is generated using RFC 7217 or randomly.

Could you simply manually add an ipv6 link local address to the
interface while it is down (ip -6 addr add fe80::..../64 dev X), then
bring the interface up (ip link set dev X up)...
All that would need to happen is the automatic link local generation
would need to be suppressed if there's already a link local ip
configured - which sounds like a good idea anyway, since why have two?
(btw. even a manually added link local ip will get deleted when the
interface gets brought back down)