From 31aa6503a15ba00182ea6dbbf51afb63bf9e851d Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Tue, 8 Jan 2019 18:12:24 -0800 Subject: [PATCH] bpf: correctly set initial window on active Fast Open sender The existing BPF TCP initial congestion window (TCP_BPF_IW) does not to work on (active) Fast Open sender. This is because it changes the (initial) window only if data_segs_out is zero -- but data_segs_out is also incremented on SYN-data. This patch fixes the issue by proerly accounting for SYN-data additionally. Fixes: fc7478103c84 ("bpf: Adds support for setting initial cwnd") Signed-off-by: Yuchung Cheng Reviewed-by: Neal Cardwell Acked-by: Lawrence Brakmo Signed-off-by: Alexei Starovoitov --- net/core/filter.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/filter.c b/net/core/filter.c index 447dd1bad31f..2b3b436ef545 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4203,7 +4203,7 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock, /* Only some options are supported */ switch (optname) { case TCP_BPF_IW: - if (val <= 0 || tp->data_segs_out > 0) + if (val <= 0 || tp->data_segs_out > tp->syn_data) ret = -EINVAL; else tp->snd_cwnd = val; -- 2.30.2