Re: [PATCH bpf-next v12 01/12] bpf: add networking timestamping support to bpf_get/setsockopt()

[Jason Xing <kerneljasonxing@gmail.com>]

On Tue, Feb 18, 2025 at 1:02 PM Jason Xing <kerneljasonxing@gmail.com> wrote:
>
> The new SK_BPF_CB_FLAGS and new SK_BPF_CB_TX_TIMESTAMPING are
> added to bpf_get/setsockopt. The later patches will implement the
> BPF networking timestamping. The BPF program will use
> bpf_setsockopt(SK_BPF_CB_FLAGS, SK_BPF_CB_TX_TIMESTAMPING) to
> enable the BPF networking timestamping on a socket.
>
> Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
> ---
>  include/net/sock.h             |  3 +++
>  include/uapi/linux/bpf.h       |  8 ++++++++
>  net/core/filter.c              | 23 +++++++++++++++++++++++
>  tools/include/uapi/linux/bpf.h |  1 +
>  4 files changed, 35 insertions(+)
>
> diff --git a/include/net/sock.h b/include/net/sock.h
> index 8036b3b79cd8..7916982343c6 100644
> --- a/include/net/sock.h
> +++ b/include/net/sock.h
> @@ -303,6 +303,7 @@ struct sk_filter;
>    *    @sk_stamp: time stamp of last packet received
>    *    @sk_stamp_seq: lock for accessing sk_stamp on 32 bit architectures only
>    *    @sk_tsflags: SO_TIMESTAMPING flags
> +  *    @sk_bpf_cb_flags: used in bpf_setsockopt()
>    *    @sk_use_task_frag: allow sk_page_frag() to use current->task_frag.
>    *                       Sockets that can be used under memory reclaim should
>    *                       set this to false.
> @@ -445,6 +446,8 @@ struct sock {
>         u32                     sk_reserved_mem;
>         int                     sk_forward_alloc;
>         u32                     sk_tsflags;
> +#define SK_BPF_CB_FLAG_TEST(SK, FLAG) ((SK)->sk_bpf_cb_flags & (FLAG))
> +       u32                     sk_bpf_cb_flags;
>         __cacheline_group_end(sock_write_rxtx);
>
>         __cacheline_group_begin(sock_write_tx);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index fff6cdb8d11a..fa666d51dffe 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -6916,6 +6916,13 @@ enum {
>         BPF_SOCK_OPS_ALL_CB_FLAGS       = 0x7F,
>  };
>
> +/* Definitions for bpf_sk_cb_flags */

nit: s/bpf_sk_cb_flags/sk_bpf_cb_flags

I will correct it.

> +enum {
> +       SK_BPF_CB_TX_TIMESTAMPING       = 1<<0,
> +       SK_BPF_CB_MASK                  = (SK_BPF_CB_TX_TIMESTAMPING - 1) |
> +                                          SK_BPF_CB_TX_TIMESTAMPING
> +};

Martin, I would like to know if it's necessary to update the above new
enum in tools/include/uapi/linux/bpf.h as well?

Thanks,
Jason