Re: [bpf-next V3 PATCH 13/14] bpf: finally expose xdp_rxq_info to XDP bpf-programs

[David Ahern <dsahern@gmail.com>]

On 12/31/17 4:02 AM, Jesper Dangaard Brouer wrote:
> Now all XDP driver have been updated to setup xdp_rxq_info and assign
> this to xdp_buff->rxq.  Thus, it is now safe to enable access to some
> of the xdp_rxq_info struct members.
> 
> This patch extend xdp_md and expose UAPI to userspace for
> ingress_ifindex and rx_queue_index.  Access happens via bpf
> instruction rewrite, that load data directly from struct xdp_rxq_info.
> 
> * ingress_ifindex map to xdp_rxq_info->dev->ifindex
> * rx_queue_index  map to xdp_rxq_info->queue_index
> 
> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
> ---
>  include/uapi/linux/bpf.h |    3 +++
>  net/core/filter.c        |   19 +++++++++++++++++++
>  2 files changed, 22 insertions(+)
> 
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 69eabfcb9bdb..a6000a95d40e 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -899,6 +899,9 @@ struct xdp_md {
>  	__u32 data;
>  	__u32 data_end;
>  	__u32 data_meta;
> +	/* Below access go though struct xdp_rxq_info */
> +	__u32 ingress_ifindex; /* rxq->dev->ifindex */
> +	__u32 rx_queue_index;  /* rxq->queue_index  */
>  };
>  
>  enum sk_action {


At some point we need to tackle the network namespace context for the
ifindex.