On Tue, Nov 15, 2022 at 8:17 AM Toke Høiland-Jørgensen <toke@xxxxxxxxxx> wrote:
>
> Stanislav Fomichev <sdf@xxxxxxxxxx> writes:
>
> > The goal is to enable end-to-end testing of the metadata
> > for AF_XDP. Current rx_timestamp kfunc returns current
> > time which should be enough to exercise this new functionality.
> >
> > Cc: John Fastabend <john.fastabend@xxxxxxxxx>
> > Cc: David Ahern <dsahern@xxxxxxxxx>
> > Cc: Martin KaFai Lau <martin.lau@xxxxxxxxx>
> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx>
> > Cc: Willem de Bruijn <willemb@xxxxxxxxxx>
> > Cc: Jesper Dangaard Brouer <brouer@xxxxxxxxxx>
> > Cc: Anatoly Burakov <anatoly.burakov@xxxxxxxxx>
> > Cc: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx>
> > Cc: Magnus Karlsson <magnus.karlsson@xxxxxxxxx>
> > Cc: Maryam Tahhan <mtahhan@xxxxxxxxxx>
> > Cc: xdp-hints@xxxxxxxxxxxxxxx
> > Cc: netdev@xxxxxxxxxxxxxxx
> > Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
> > ---
> > drivers/net/veth.c | 14 ++++++++++++++
> > 1 file changed, 14 insertions(+)
> >
> > diff --git a/drivers/net/veth.c b/drivers/net/veth.c
> > index 2a4592780141..c626580a2294 100644
> > --- a/drivers/net/veth.c
> > +++ b/drivers/net/veth.c
> > @@ -25,6 +25,7 @@
> > #include <linux/filter.h>
> > #include <linux/ptr_ring.h>
> > #include <linux/bpf_trace.h>
> > +#include <linux/bpf_patch.h>
> > #include <linux/net_tstamp.h>
> >
> > #define DRV_NAME "veth"
> > @@ -1659,6 +1660,18 @@ static int veth_xdp(struct net_device *dev, struct netdev_bpf *xdp)
> > }
> > }
> >
> > +static void veth_unroll_kfunc(const struct bpf_prog *prog, u32 func_id,
> > + struct bpf_patch *patch)
> > +{
> > + if (func_id == xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP_SUPPORTED)) {
> > + /* return true; */
> > + bpf_patch_append(patch, BPF_MOV64_IMM(BPF_REG_0, 1));
> > + } else if (func_id == xdp_metadata_kfunc_id(XDP_METADATA_KFUNC_RX_TIMESTAMP)) {
> > + /* return ktime_get_mono_fast_ns(); */
> > + bpf_patch_append(patch, BPF_EMIT_CALL(ktime_get_mono_fast_ns));
> > + }
> > +}
>
> So these look reasonable enough, but would be good to see some examples
> of kfunc implementations that don't just BPF_CALL to a kernel function
> (with those helper wrappers we were discussing before).
Let's maybe add them if/when needed as we add more metadata support?
xdp_metadata_export_to_skb has an example, and rfc 1/2 have more
examples, so it shouldn't be a problem to resurrect them back at some
point?
