On Thu, 5 Apr 2018 09:47:37 +0200
Victor Julien <lists@...> wrote:

Option#2: Invent a new 'ip link set xdp' netlink msg with a query option.

Do you have an example of how this is queried?

The code for querying should not be too difficult.

It would likely be similar to how we currently "set"/attach an XDP
program, via its BPF file-descriptor to an ifindex. Eric Leblond,
choose to hide this in the kernel library "libbpf", see code:

function bpf_set_link_xdp_fd()
https://github.com/torvalds/linux/blob/master/tools/lib/bpf/bpf.c#L456-L575

Given Suricata already depend on libbpf for eBFP and XDP support, then
it might make sense to add an API call to "get" XDP link info, e.g.
bpf_get_link_xdp_features(int ifindex) ?

--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer