[PATCH 4/8] tcp: Acknowledge everything if sending buffer is less than SNDBUF_BIG

[Stefano Brivio <sbrivio@redhat.com>]

...instead of checking if it's less than SNDBUF_SMALL, because this
isn't simply an optimisation to coalesce ACK segments: we rely on
having enough data at once from the sender to make the buffer grow
by means of TCP buffer size tuning implemented in the Linux kernel.

Use SNDBUF_BIG: above that, we don't need auto-tuning (even though
it might happen). SNDBUF_SMALL is too... small.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
---
 tcp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tcp.c b/tcp.c
index e4c5a5b..fbf97a0 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1079,7 +1079,7 @@ int tcp_update_seqack_wnd(const struct ctx *c, struct tcp_tap_conn *conn,
 	if (bytes_acked_cap && !force_seq &&
 	    !CONN_IS_CLOSING(conn) &&
 	    !(conn->flags & LOCAL) && !tcp_rtt_dst_low(conn) &&
-	    (unsigned)SNDBUF_GET(conn) >= SNDBUF_SMALL) {
+	    (unsigned)SNDBUF_GET(conn) >= SNDBUF_BIG) {
 		if (!tinfo) {
 			tinfo = &tinfo_new;
 			if (getsockopt(s, SOL_TCP, TCP_INFO, tinfo, &sl))
-- 
2.43.0