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?
This will usually be false, as timestamps are taken outside the
protocol layers.
> + }
> +
> + sock_ops.sk = sk;
> + sock_ops.op = op;
> + if (nargs > 0)
> + memcpy(sock_ops.args, args, nargs * sizeof(*args));
> +
> + BPF_CGROUP_RUN_PROG_SOCK_OPS_SK(&sock_ops, sk);
> +}
> +
