On Tue, Dec 01, 2020 at 08:43:56AM -0800, Prankur gupta wrote:
> Adds a new bpf_setsockopt for TCP sockets, TCP_BPF_WINDOW_CLAMP,
> which sets the maximum receiver window size. It will be useful for
> limiting receiver window based on RTT.
>
> Signed-off-by: Prankur gupta <prank...@fb.com>
> ---
> net/core/filter.c | 13 +++++++++++++
> 1 file changed, 13 insertions(+)
>
> diff --git a/net/core/filter.c b/net/core/filter.c
> index 2ca5eecebacf..8c52ffae7b0c 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -4910,6 +4910,19 @@ static int _bpf_setsockopt(struct sock *sk, int level,
> int optname,
> tp->notsent_lowat = val;
> sk->sk_write_space(sk);
> break;
> + case TCP_WINDOW_CLAMP:
> + if (!val) {
> + if (sk->sk_state != TCP_CLOSE) {
> + ret = -EINVAL;
> + break;
> + }
> + tp->window_clamp = 0;
> + } else {
> + tp->window_clamp =
> + val < SOCK_MIN_RCVBUF / 2 ?
> + SOCK_MIN_RCVBUF / 2 : val;
> + }
May be extract this logic into a helper instead of copy-paste?
