On Tue, Oct 29, 2024 at 9:02 AM Willem de Bruijn
<willemdebruijn.kernel@xxxxxxxxx> wrote:
>
> Jason Xing wrote:
> > From: Jason Xing <kernelxing@xxxxxxxxxxx>
> >
> > Introduce BPF_SOCK_OPS_TS_SCHED_OPT_CB flag so that we can decide to
> > print timestamps when the skb just passes the dev layer.
> >
> > Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
> > ---
> > include/uapi/linux/bpf.h | 5 +++++
> > net/core/skbuff.c | 31 ++++++++++++++++++++++++++++++-
> > tools/include/uapi/linux/bpf.h | 5 +++++
> > 3 files changed, 40 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index e8241b320c6d..324e9e40969c 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -7013,6 +7013,11 @@ enum {
> > * by the kernel or the
> > * earlier bpf-progs.
> > */
> > + BPF_SOCK_OPS_TS_SCHED_OPT_CB, /* Called when skb is passing through
> > + * dev layer when SO_TIMESTAMPING
> > + * feature is on. It indicates the
> > + * recorded timestamp.
> > + */
> > };
> >
> > /* List of TCP states. There is a build check in net/ipv4/tcp.c to detect
> > diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> > index 39309f75e105..e6a5c883bdc6 100644
> > --- a/net/core/skbuff.c
> > +++ b/net/core/skbuff.c
> > @@ -64,6 +64,7 @@
> > #include <linux/mpls.h>
> > #include <linux/kcov.h>
> > #include <linux/iov_iter.h>
> > +#include <linux/bpf-cgroup.h>
> >
> > #include <net/protocol.h>
> > #include <net/dst.h>
> > @@ -5621,13 +5622,41 @@ static void skb_tstamp_tx_output(struct sk_buff *orig_skb,
> > __skb_complete_tx_timestamp(skb, sk, tstype, opt_stats);
> > }
> >
> > +static void timestamp_call_bpf(struct sock *sk, int op, u32 nargs, u32 *args)
> > +{
> > + struct bpf_sock_ops_kern sock_ops;
> > +
> > + memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp));
> > + if (sk_fullsock(sk)) {
> > + sock_ops.is_fullsock = 1;
> > + sock_owned_by_me(sk);
>
> Why this check?
I imitated the use of BPF_CGROUP_RUN_PROG_SOCK_OPS.
>
> This will usually be false, as timestamps are taken outside the
> protocol layers.
I will remove this if branch.
Thanks,
Jason
