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: fc74781 ("bpf: Adds support for setting initial cwnd") Signed-off-by: Yuchung Cheng <[email protected]> Reviewed-by: Neal Cardwell <[email protected]> Acked-by: Lawrence Brakmo <[email protected]> Signed-off-by: Alexei Starovoitov <[email protected]>
josf · Jan 9, 2019 · 31aa650 · 31aa650
1 parent d972f3d
commit 31aa650
Showing 1 changed file with 1 addition and 1 deletion.
diff --git 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;