Commit 31aa6503 authored Jan 08, 2019 by Yuchung Cheng Committed by Alexei Starovoitov Jan 09, 2019

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: fc747810 ("bpf: Adds support for setting initial cwnd")
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Lawrence Brakmo <brakmo@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

parent d972f3dc

net/core/filter.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;

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