[PATCH v12 07/12] net/tap: use libbpf to load new BPF program

[Stephen Hemminger]

On Mon, 20 May 2024 18:49:19 +0100
Ferruh Yigit <ferruh.yigit at amd.com> wrote:

> On 5/2/2024 10:31 PM, Stephen Hemminger wrote:
> > There were multiple issues in the RSS queue support in the TAP
> > driver. This required extensive rework of the BPF support.
> > 
> > Change the BPF loading to use bpftool to
> > create a skeleton header file, and load with libbpf.
> > The BPF is always compiled from source so less chance that
> > source and instructions diverge. Also resolves issue where
> > libbpf and source get out of sync. The program
> > is only loaded once, so if multiple rules are created
> > only one BPF program is loaded in kernel.
> > 
> > The new BPF program only needs a single action.
> > No need for action and re-classification step.
> > 
> > It also fixes the missing bits from the original.
> >     - supports setting RSS key per flow
> >     - level of hash can be L3 or L3/L4.
> > 
> > Bugzilla ID: 1329
> > 
> > Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
> >  
> 
> 
> The libbpf version in my Ubuntu box, installed with package manager, is
> 'libbpf.so.0.5.0', so it doesn't satisfy the requirement and bpf support
> is not compiled for me.
> 
> 
> @Christian, 'libbpf.so.0.5.0'seems old, it is from 2021, do you know is
> there a reason Ubuntu stick to this version? And can we expect an update
> soon?
> 
> 
> @Patric, I assume test environment also doesn't have 'libbpf', version:
> '>= 1.0' which we need to test this feature.  
> Is it possible to update test environment to justify this dependency?
> 
> I think we need to verify at least build (with and without dependency
> met) for the set.

The BPF API changed a lot, and it is not really possible to support
both.