Re: Should I add BPF kfuncs for userspace apps? And how?

[Song Liu]

Hi Akihiko,

On Tue, Dec 12, 2023 at 12:05 AM Akihiko Odaki <akihiko.odaki@xxxxxxxxxx> wrote:
>
[...]
> ---
>
> I'm working on a new feature that aids virtio-net implementations using
> tuntap virtual network device. You can see [1] for details, but
> basically it's to extend BPF_PROG_TYPE_SOCKET_FILTER to report four more
> bytes.

AFAICT, [1] adds a new program type, which is really hard to ship. However,
you mentioned it is basically "extend BPF_PROG_TYPE_SOCKET_FILTER to
report four more bytes", which confuses me.

Can we achieve the same goal by extending BPF_PROG_TYPE_SOCKET_FILTER
(without adding a new program type)? Does this require extending
__sk_buff, which
is also not an option any more?

Thanks,
Song