Subject: Re: [PATCH bpf-next v2 4/8] xsk: register XDP sockets at bind(), and add new AF_XDP BPF helper

From: Toke Høiland-Jørgensen <[email-masked]>
Date: Wed, 20 Jan 2021 13:50:24 +0100

Björn Töpel <[email-masked]> writes:

> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index c001766adcbc..bbc7d9a57262 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -3836,6 +3836,12 @@ union bpf_attr {
>   *	Return
>   *		A pointer to a struct socket on success or NULL if the file is
>   *		not a socket.
> + *
> + * long bpf_redirect_xsk(struct xdp_buff *xdp_md, u64 action)
> + *	Description
> + *		Redirect to the registered AF_XDP socket.
> + *	Return
> + *		**XDP_REDIRECT** on success, otherwise the action parameter is returned.
>   */

I think it would be better to make the second argument a 'flags'
argument and make values > XDP_TX invalid (like we do in
bpf_xdp_redirect_map() now). By allowing any value as return you lose
the ability to turn it into a flags argument later...

-Toke