From 99355e25b9bd59f0e3d59245e10c765e7edfb213 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 26 Mar 2024 16:42:21 +1100 Subject: [PATCH] tcp: Split handling of DUP_ACK from ACK The DUP_ACK flag to tcp_send_flag() has two effects: first it forces the setting of the ACK flag in the packet, even if we otherwise wouldn't. Secondly, it causes a duplicate of the flags packet to be sent immediately after the first. Setting the ACK flag to tcp_send_flag() also has the first effect, so instead of having DUP_ACK also do that, pass both flags when we need both operations. This slightly simplifies the logic of tcp_send_flag() in a way that makes some future changes easier. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tcp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/tcp.c b/tcp.c index a1860d1..edd3d89 100644 --- a/tcp.c +++ b/tcp.c @@ -1677,7 +1677,7 @@ static int tcp_send_flag(struct ctx *c, struct tcp_tap_conn *conn, int flags) th->ack = !!(flags & ACK); } else { - th->ack = !!(flags & (ACK | DUP_ACK)) || + th->ack = !!(flags & ACK)) || conn->seq_ack_to_tap != prev_ack_to_tap || !prev_wnd_to_tap; } @@ -2503,7 +2503,7 @@ out: */ if (conn->seq_dup_ack_approx != (conn->seq_from_tap & 0xff)) { conn->seq_dup_ack_approx = conn->seq_from_tap & 0xff; - tcp_send_flag(c, conn, DUP_ACK); + tcp_send_flag(c, conn, ACK | DUP_ACK); } return p->count - idx; }