Jason Xing wrote:
> From: Jason Xing <kernelxing@xxxxxxxxxxx>
>
> Prepare for later changes in this series. Here I use u32 for
> bpf_sock_ops_cb_flags for better extension and introduce a new
> rx bpf flag to control separately.
>
> Main change is let userside set through bpf_setsockopt() for
> SO_TIMESTAMPING feature.
>
> Signed-off-by: Jason Xing <kernelxing@xxxxxxxxxxx>
> ---
> include/linux/tcp.h | 2 +-
> include/net/tcp.h | 2 +-
> include/uapi/linux/bpf.h | 5 ++++-
> net/core/filter.c | 6 +++++-
> net/ipv4/tcp.c | 13 ++++++++++++-
> tools/include/uapi/linux/bpf.h | 5 ++++-
> 6 files changed, 27 insertions(+), 6 deletions(-)
>
> diff --git a/include/linux/tcp.h b/include/linux/tcp.h
> index 6a5e08b937b3..e21fd3035962 100644
> --- a/include/linux/tcp.h
> +++ b/include/linux/tcp.h
> @@ -446,7 +446,7 @@ struct tcp_sock {
>
> /* Sock_ops bpf program related variables */
> #ifdef CONFIG_BPF
> - u8 bpf_sock_ops_cb_flags; /* Control calling BPF programs
> + u32 bpf_sock_ops_cb_flags; /* Control calling BPF programs
> * values defined in uapi/linux/tcp.h
> */
> u8 bpf_chg_cc_inprogress:1; /* In the middle of
> diff --git a/include/net/tcp.h b/include/net/tcp.h
> index 739a9fb83d0c..728db7107074 100644
> --- a/include/net/tcp.h
> +++ b/include/net/tcp.h
> @@ -423,7 +423,7 @@ int tcp_set_rcvlowat(struct sock *sk, int val);
> int tcp_set_window_clamp(struct sock *sk, int val);
> void tcp_update_recv_tstamps(struct sk_buff *skb,
> struct scm_timestamping_internal *tss);
> -void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
> +void tcp_recv_timestamp(struct msghdr *msg, struct sock *sk,
> struct scm_timestamping_internal *tss);
> void tcp_data_ready(struct sock *sk);
> #ifdef CONFIG_MMU
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 1b478ec18ac2..d2754f155cf7 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -6903,8 +6903,11 @@ enum {
> /* Call bpf when the kernel is generating tx timestamps.
> */
> BPF_SOCK_OPS_TX_TIMESTAMPING_OPT_CB_FLAG = (1<<7),
> + /* Call bpf when the kernel is generating rx timestamps.
> + */
> + BPF_SOCK_OPS_RX_TIMESTAMPING_OPT_CB_FLAG = (1<<8),
> /* Mask of all currently supported cb flags */
> - BPF_SOCK_OPS_ALL_CB_FLAGS = 0xFF,
> + BPF_SOCK_OPS_ALL_CB_FLAGS = 0x1FF,
> };
>
> /* List of known BPF sock_ops operators.
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 3b4afaa273d9..36b357b76f4a 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -5216,14 +5216,18 @@ static int bpf_sock_set_timestamping(struct sock *sk,
> return -EINVAL;
>
> if (!(flags & (SOF_TIMESTAMPING_TX_SCHED | SOF_TIMESTAMPING_TX_SOFTWARE |
> - SOF_TIMESTAMPING_TX_ACK)))
> + SOF_TIMESTAMPING_TX_ACK | SOF_TIMESTAMPING_RX_SOFTWARE)))
> return -EINVAL;
>
> ret = sock_set_tskey(sk, flags, BPFPROG_TS_REQUESTOR);
> if (ret)
> return ret;
>
> + if (flags & SOF_TIMESTAMPING_RX_SOFTWARE)
> + sock_enable_timestamp(sk, SOCK_TIMESTAMPING_RX_SOFTWARE);
> +
> WRITE_ONCE(sk->sk_tsflags[BPFPROG_TS_REQUESTOR], flags);
> +
> static_branch_enable(&bpf_tstamp_control);
>
> return 0;
> diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
> index d37e231b2737..0891b41bc745 100644
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2260,14 +2260,25 @@ static int tcp_zerocopy_receive(struct sock *sk,
> }
> #endif
>
> +static void tcp_bpf_recv_timestamp(struct sock *sk, struct scm_timestamping_internal *tss)
> +{
> + struct tcp_sock *tp = tcp_sk(sk);
> +
> + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RX_TIMESTAMPING_OPT_CB_FLAG))
> + return;
> +}
> +
> /* Similar to __sock_recv_timestamp, but does not require an skb */
> -void tcp_recv_timestamp(struct msghdr *msg, const struct sock *sk,
> +void tcp_recv_timestamp(struct msghdr *msg, struct sock *sk,
> struct scm_timestamping_internal *tss)
> {
> int new_tstamp = sock_flag(sk, SOCK_TSTAMP_NEW);
> u32 tsflags = READ_ONCE(sk->sk_tsflags[SOCKETOPT_TS_REQUESTOR]);
> bool has_timestamping = false;
>
> + if (static_branch_unlikely(&bpf_tstamp_control))
> + tcp_bpf_recv_timestamp(sk, tss);
> +
> if (tss->ts[0].tv_sec || tss->ts[0].tv_nsec) {
> if (sock_flag(sk, SOCK_RCVTSTAMP)) {
> if (sock_flag(sk, SOCK_RCVTSTAMPNS)) {
tcp_recv_timestamp is called from tcp_recvmsg only conditionally:
if ((cmsg_flags || msg->msg_get_inq) && ret >= 0) {
if (cmsg_flags & TCP_CMSG_TS)
tcp_recv_timestamp(msg, sk, &tss);
How do you get this triggered for your BPF program?
And also check the other caller, tcp_zc_finalize_rx_tstamp.
