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

[Daniel Borkmann]

On 6/27/23 10:56 AM, Lorenz Bauer wrote:
> 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.

If it breaks the build, then we need to export it.