Re: [nf-next PATCH] netfilter: nfnetlink_hook: Dump nat type chains

[Phil Sutter <phil@nwl.cc>]

On Fri, Mar 20, 2026 at 11:17:00AM +0100, Phil Sutter wrote:
[...]
> A remark from a practical perspective: Florian's suggestion to dump the
> nat-type chains in their order with the dispatcher's priority value is
> super-easy to implement (just have to pass the priority value to
> nfnl_hook_dump_one() via parameter) and does not require adjustments in
> user space.

Famous last words. :(

In fact, user space calls basehook_list_add_tail() for each received
hook message which (contrary to its name) inserts sorted by ascending
priority value. It does this by skipping as long as the cursor's
priority is lower than the new element's, i.e. hooks with same priority
value are inserted in reverse order than received. This is a no-go since
ordering matters, right?

Cheers, Phil