On 12/28/17, 9:58 AM, "Yuchung Cheng" <ych...@google.com> wrote:
On Thu, Dec 21, 2017 at 5:20 PM, Lawrence Brakmo <bra...@fb.com> wrote:
>
> Adds an optional call to sock_ops BPF program based on whether the
> BPF_SOCK_OPS_RTO_CB_FLAG is set in bpf_sock_ops_flags.
> The BPF program is passed 2 arguments: icsk_retransmits and whether the
> RTO has expired.
>
> Signed-off-by: Lawrence Brakmo <bra...@fb.com>
> ---
> include/uapi/linux/bpf.h | 5 +++++
> include/uapi/linux/tcp.h | 3 +++
> net/ipv4/tcp_timer.c | 9 +++++++++
> 3 files changed, 17 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 62b2c89..3cf9014 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -995,6 +995,11 @@ enum {
> * a congestion threshold. RTTs
above
> * this indicate congestion
> */
> + BPF_SOCK_OPS_RTO_CB, /* Called when an RTO has
triggered.
> + * Arg1: value of icsk_retransmits
> + * Arg2: value of icsk_rto
> + * Arg3: whether RTO has expired
> + */
> };
>
> #define TCP_BPF_IW 1001 /* Set TCP initial congestion
window */
> diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h
> index b4a4f64..089c19e 100644
> --- a/include/uapi/linux/tcp.h
> +++ b/include/uapi/linux/tcp.h
> @@ -259,6 +259,9 @@ struct tcp_md5sig {
> __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
> };
>
> +/* Definitions for bpf_sock_ops_flags */
> +#define BPF_SOCK_OPS_RTO_CB_FLAG (1<<0)
> +
> /* INET_DIAG_MD5SIG */
> struct tcp_diag_md5sig {
> __u8 tcpm_family;
> diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c
> index 6db3124..f9c57e2 100644
> --- a/net/ipv4/tcp_timer.c
> +++ b/net/ipv4/tcp_timer.c
> @@ -215,9 +215,18 @@ static int tcp_write_timeout(struct sock *sk)
> tcp_fastopen_active_detect_blackhole(sk, expired);
can't we just call it here once w/ 'expired' as a parameter, instead
of duplicating the code?
Good point, I will fix it. Thanks!
> if (expired) {
> /* Has it gone just too far? */
> + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RTO_CB_FLAG))
> + tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RTO_CB,
> + icsk->icsk_retransmits,
> + icsk->icsk_rto, 1);
> tcp_write_err(sk);
> return 1;
> }
> +
> + if (BPF_SOCK_OPS_TEST_FLAG(tp, BPF_SOCK_OPS_RTO_CB_FLAG))
> + tcp_call_bpf_3arg(sk, BPF_SOCK_OPS_RTO_CB,
> + icsk->icsk_retransmits,
> + icsk->icsk_rto, 0);
> return 0;
> }
>
> --
> 2.9.5
>
