On Mon, 2025-09-08 at 09:08 +0000, Asbjørn Sloth Tønnesen wrote:

Thank you for the consensus write up. Should we prohibit indexed-array with sub-type
nest for families with a genetlink protocol?

It is currently only used in families with a netlink-raw or genetlink-legacy protocol.

I have no strong opinion on that, but I guess maybe so? At least print
out a warning for anyone who's trying to add such a new thing perhaps,
so that new stuff that isn't just a port (to ynl) or annotation of
existing APIs doesn't add it.

quoted

I can't get rid of the nested array types in nl80211 though, of course.

Wireguard is already in the same boat. [...]

Oh, sorry. I didn't look at the linked patch and thought it was adding
such a new thing. Looking now, I see it just makes the policy validate
it instead of (only) doing it in the code. (FWIW, in the code you could
then also set the policy argument for nla_parse_nested() calls to NULL.)

Given that, as Jacob pointed out, there are more families with nested arrays in
their YNL spec, than those using NLA_NESTED_ARRAY, then it appears that there
are more families already in the boat.

Right.

johannes