Jason Xing wrote:
> From: Jason Xing <kernelxing@xxxxxxxxxxx>
>
> Implement basic codes so that we later can easily add each tx points.
> Introducing BPF_SOCK_OPS_ALL_CB_FLAGS used as a test statement can help use
> control whether to output or not.
>
> Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 5 ++++-
> net/core/skbuff.c | 18 ++++++++++++++++++
> tools/include/uapi/linux/bpf.h | 5 ++++-
> 3 files changed, 26 insertions(+), 2 deletions(-)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index c6cd7c7aeeee..157e139ed6fc 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -6900,8 +6900,11 @@ enum {
> * options first before the BPF program does.
> */
> BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG = (1<<6),
> + /* Call bpf when the kernel is generating tx timestamps.
> + */
> + BPF_SOCK_OPS_TX_TIMESTAMPING_OPT_CB_FLAG = (1<<7),
> /* Mask of all currently supported cb flags */
> - BPF_SOCK_OPS_ALL_CB_FLAGS = 0x7F,
> + BPF_SOCK_OPS_ALL_CB_FLAGS = 0xFF,
> };
>
> /* List of known BPF sock_ops operators.
> diff --git a/net/core/skbuff.c b/net/core/skbuff.c
> index 74149dc4ee31..5ff1a91c1204 100644
> --- a/net/core/skbuff.c
> +++ b/net/core/skbuff.c
> @@ -5539,6 +5539,21 @@ void skb_complete_tx_timestamp(struct sk_buff *skb,
> }
> EXPORT_SYMBOL_GPL(skb_complete_tx_timestamp);
>
> +static bool bpf_skb_tstamp_tx(struct sock *sk, u32 scm_flag,
> + struct skb_shared_hwtstamps *hwtstamps)
> +{
> + struct tcp_sock *tp;
> +
> + if (!sk_is_tcp(sk))
> + return false;
> +
> + tp = tcp_sk(sk);
> + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_TX_TIMESTAMPING_OPT_CB_FLAG))
> + return true;
> +
> + return false;
> +}
> +
> void __skb_tstamp_tx(struct sk_buff *orig_skb,
> const struct sk_buff *ack_skb,
> struct skb_shared_hwtstamps *hwtstamps,
> @@ -5551,6 +5566,9 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
> if (!sk)
> return;
>
> + if (bpf_skb_tstamp_tx(sk, tstype, hwtstamps))
> + return;
> +
Eventually, this whole feature could probably be behind a
static_branch.
