On Mon, Nov 21, 2022 at 10:47 AM Jakub Kicinski <kuba@xxxxxxxxxx> wrote: > > On Mon, 21 Nov 2022 09:53:02 -0800 Stanislav Fomichev wrote: > > > Jakub was objecting to putting it in the UAPI header, but didn't we > > > already agree that this wasn't necessary? > > > > > > I.e., if we just define > > > > > > struct xdp_skb_metadata *bpf_xdp_metadata_export_to_skb() > > > > > > as a kfunc, the xdp_skb_metadata struct won't appear in any UAPI headers > > > and will only be accessible via BTF? And we can put the actual data > > > wherever we choose, since that bit is nicely hidden behind the kfunc, > > > while the returned pointer still allows programs to access it. > > > > > > We could even make that kfunc smart enough that it checks if the field > > > is already populated and just return the pointer to the existing data > > > instead of re-populating it int his case (with a flag to override, > > > maybe?). > > > > Even if we only expose it via btf, I think the fact that we still > > expose a somewhat fixed layout is the problem? > > I'm not sure the fact that we're not technically putting in the uapi > > header is the issue here, but maybe I'm wrong? > > Jakub? > > Until the device metadata access from BPF is in bpf-next the only > opinion I have on this is something along the lines of "not right now". > > I may be missing some concerns / perspectives, in which case - when > is the next "BPF office hours" meeting? SG! Let's get back to it once we get the basic rx metadata sorted out. I'll probably look at the tx part next though; that xdp->skb path is of least priority for me.
