[PATCH v5 7/8] net/tap: use libbpf to load new BPF program

[Luca Boccassi]

On Wed, 3 Apr 2024 at 16:55, Stephen Hemminger
<stephen at networkplumber.org> wrote:
>
> On Wed, 03 Apr 2024 12:50:35 +0100
> Luca Boccassi <bluca at debian.org> wrote:
>
> > Using bpftool to generate the header at build time is a bit icky,
> > because it will look at sysfs on the build system, which is from the
> > running kernel. But a build system's kernel might be some ancient LTS,
> > and even be a completely different kconfig/build/distro from the actual
> > runtime one.
>
> One other option would be to ship a pre-built skeleton file.
> Which is what the method the old code did.
> But that creates an implied dependency on the developers machine build environment.

That's what the distro-provided vmlinux.h should help with - by
#include'ing that, it should be possible to build a co-re bpf program,
no other artifacts needed. You can try it out locally by generating it
from the local running kernel on your dev machine:

bpftool btf dump file /sys/kernel/btf/vmlinux format c > vmlinux.h