4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit 31aa6503a15ba00182ea6dbbf51afb63bf9e851d ]
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 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 Signed-off-by: Sasha Levin sashal@kernel.org --- 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 8c2411fb25090..3400c7abda135 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -4001,7 +4001,7 @@ 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;