Re: [RFC PATCH net-next v6 07/13] net-timestamp: support sw SCM_TSTAMP_SND for bpf extension

[Martin KaFai Lau <martin.lau@linux.dev>]

On 1/20/25 5:28 PM, Jason Xing wrote:
> Support SCM_TSTAMP_SND case. Then we will get the software
> timestamp when the driver is about to send the skb. Later, I
> will support the hardware timestamp.
> 
> Signed-off-by: Jason Xing <kerneljasonxing@gmail.com>
> ---
>   include/linux/skbuff.h         |  2 +-
>   include/uapi/linux/bpf.h       |  5 +++++
>   net/core/skbuff.c              | 10 ++++++++--
>   tools/include/uapi/linux/bpf.h |  5 +++++
>   4 files changed, 19 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 35c2e864dd4b..de8d3bd311f5 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -4569,7 +4569,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
>   static inline void skb_tx_timestamp(struct sk_buff *skb)
>   {
>   	skb_clone_tx_timestamp(skb);
> -	if (skb_shinfo(skb)->tx_flags & SKBTX_SW_TSTAMP)
> +	if (skb_shinfo(skb)->tx_flags & (SKBTX_SW_TSTAMP | SKBTX_BPF))
>   		__skb_tstamp_tx(skb, NULL, NULL, skb->sk, true, SCM_TSTAMP_SND);
>   }
>   
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 72f93c6e45c1..a6d761f07f67 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -7027,6 +7027,11 @@ enum {
>   					 * feature is on. It indicates the
>   					 * recorded timestamp.
>   					 */
> +	BPF_SOCK_OPS_TS_SW_OPT_CB,	/* Called when skb is about to send
> +					 * to the nic when SO_TIMESTAMPING

Same comment on the "SO_TIMESTAMPING".