[Oisf-devel] Best userspace programming API for XDP features query to kernel?

[Jesper Dangaard Brouer]

On Thu, 5 Apr 2018 09:47:37 +0200
Victor Julien <lists at inliniac.net> 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