XDP Support

[huseyinsaatci]

I was using ebpf_exporter in my project and realized that there is no XDP support in the project. I forked the project and edited it to support XDP programs. I used libbpfgo's AttachXDP function to attach the XDP program to the required interface.

My edit contains two new fields in YAML files: is_xdp to indicate if the metric has an XDP program, and interfaces is an array with interfaces to attach the XDP program. And usage is like:

is_xdp: true
interfaces: ["enp8s0", "docker0"]

If you consider it worth adding support for XDP programs I can open a PR.

[bobrik]

What do you think about using SEC("xdp/enp8s0") instead (see: #154)? The downside is that the interface is hardcoded in a program, but the upside is that it's consistent with other SEC setups.

In your setup I don't think there's a need for is_xdp. You can detect it from SEC("xdp"). Having interfaces set in the config means that you attach all programs to all interfaces. I can imagine cases where you'd want to have different programs on different interfaces as a part of the same config.

[huseyinsaatci]

Makes sense but when I try to use SEC("xdp/enp8s0") in my program I get this error:

missing BPF prog type, check ELF section name 'xdp/enp8s0
failed to load: -22
Error attaching exporter: error loading bpf object from "src/xdp.bpf.o" for config "xdp": failed to load BPF object: invalid argument'

I don't think it recognizes 'xdp/enp8s0' as an XDP program.
It is possible to get the interface from the SEC part but only if this problem can be solved.

[bobrik]

I linked #154 because it implemented SEC("perf_event/type=0,config=3,frequency=99").

You can do a similar thing here to implement SEC("xdp/enp8s0").

[huseyinsaatci]

Okay, I will examine the codes and try to implement a similar one. I hope it's not a problem if I ask questions about the codes if I have problems.

[bobrik]

I merged #215, thanks!