On Sat, 3 Dec 2016 19:17:23 -0800 Martin KaFai Lau <ka...@fb.com> wrote:
> This patch allows XDP prog to extend/remove the packet
> data at the head (like adding or removing header). It is
> done by adding a new XDP helper bpf_xdp_adjust_head().
>
> It also renames bpf_helper_changes_skb_data() to
> bpf_helper_changes_pkt_data() to better reflect
> that XDP prog does not work on skb.
>
> Acked-by: Alexei Starovoitov <a...@kernel.org>
> Signed-off-by: Martin KaFai Lau <ka...@fb.com>
> ---
[...]
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 56b43587d200..ccef948cf58a 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -2234,7 +2234,34 @@ static const struct bpf_func_proto
> bpf_skb_change_head_proto = {
> .arg3_type = ARG_ANYTHING,
> };
>
> -bool bpf_helper_changes_skb_data(void *func)
> +BPF_CALL_2(bpf_xdp_adjust_head, struct xdp_buff *, xdp, int, offset)
> +{
> + /* Both mlx4 and mlx5 driver align each packet to PAGE_SIZE when
> + * XDP prog is set.
> + * If the above is not true for the other drivers to support
> + * bpf_xdp_adjust_head, struct xdp_buff can be extended.
> + */
> + unsigned long addr = (unsigned long)xdp->data & PAGE_MASK;
> + void *data_hard_start = (void *)addr;
> + void *data = xdp->data + offset;
> +
> + if (unlikely(data < data_hard_start || data > xdp->data_end - ETH_HLEN))
> + return -EINVAL;
> +
> + xdp->data = data;
> +
> + return 0;
> +}
Thanks for adjusting this, I like Daniel's suggestion.
For this patch:
Acked-by: Jesper Dangaard Brouer <bro...@redhat.com>
As it still looks like 3/4 need some adjustments based on Saeed's
comments.
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
