From 13d3b1ebe28762c79e981931a41914fae5d04386 Mon Sep 17 00:00:00 2001 From: Lawrence Brakmo Date: Fri, 30 Jun 2017 20:02:44 -0700 Subject: bpf: Support for setting initial receive window This patch adds suppport for setting the initial advertized window from within a BPF_SOCK_OPS program. This can be used to support larger initial cwnd values in environments where it is known to be safe. Signed-off-by: Lawrence Brakmo Signed-off-by: David S. Miller --- net/ipv4/tcp_minisocks.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'net/ipv4/tcp_minisocks.c') diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index d30ee31e94eb..0ff83c1637d8 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -351,6 +351,7 @@ void tcp_openreq_init_rwin(struct request_sock *req, int full_space = tcp_full_space(sk_listener); u32 window_clamp; __u8 rcv_wscale; + u32 rcv_wnd; int mss; mss = tcp_mss_clamp(tp, dst_metric_advmss(dst)); @@ -363,6 +364,12 @@ void tcp_openreq_init_rwin(struct request_sock *req, (req->rsk_window_clamp > full_space || req->rsk_window_clamp == 0)) req->rsk_window_clamp = full_space; + rcv_wnd = tcp_rwnd_init_bpf((struct sock *)req); + if (rcv_wnd == 0) + rcv_wnd = dst_metric(dst, RTAX_INITRWND); + else if (full_space < rcv_wnd * mss) + full_space = rcv_wnd * mss; + /* tcp_full_space because it is guaranteed to be the first packet */ tcp_select_initial_window(full_space, mss - (ireq->tstamp_ok ? TCPOLEN_TSTAMP_ALIGNED : 0), @@ -370,7 +377,7 @@ void tcp_openreq_init_rwin(struct request_sock *req, &req->rsk_window_clamp, ireq->wscale_ok, &rcv_wscale, - dst_metric(dst, RTAX_INITRWND)); + rcv_wnd); ireq->rcv_wscale = rcv_wscale; } EXPORT_SYMBOL(tcp_openreq_init_rwin); -- cgit v1.2.3-59-g8ed1b