Re: [PATCH bpf-next v3 2/7] net: export inet_lookup_reuseport and inet6_lookup_reuseport

[Lorenz Bauer]

On Mon, Jun 26, 2023 at 6:33 PM Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> wrote:
>
> From: Lorenz Bauer <lmb@xxxxxxxxxxxxx>
> Date: Mon, 26 Jun 2023 16:08:59 +0100
> > Rename the existing reuseport helpers for IPv4 and IPv6 so that they
> > can be invoked in the follow up commit. Export them so that DCCP which
> > may be built as a module can access them.
>
> We need not export the functions unless there is a real user.
>
> I added a deprecation notice for DCCP recently, so I bet DCCP
> will not get SO_REUSEPORT support.
> https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=b144fcaf46d4

Misleading commit message, it turns out that ipv6 as a module also
needs (the v6 functions at least) to be EXPORT_SYMBOL'd. That's
because of some special shenanigans where inet6_hashtables.c is linked
into vmlinux even when CONFIG_IPV6=m.

Also not sure how to work around this: DCCP may be deprecated but
without the export a module build of it fails.