tcp: fix off-by-one bug in RACK

RACK should mark a packet lost when remaining wait time is zero.

Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_recovery.c b/net/ipv4/tcp_recovery.c
index 3143664..0c18230 100644 (file)
--- a/net/ipv4/tcp_recovery.c
+++ b/net/ipv4/tcp_recovery.c
@@ -80,12 +80,12 @@ static void tcp_rack_detect_loss(struct sock *sk, u32 *reo_timeout)
                 */
                remaining = tp->rack.rtt_us + reo_wnd -
                            tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp);
-               if (remaining < 0) {
+               if (remaining <= 0) {
                        tcp_rack_mark_skb_lost(sk, skb);
                        list_del_init(&skb->tcp_tsorted_anchor);
                } else {
-                       /* Record maximum wait time (+1 to avoid 0) */
-                       *reo_timeout = max_t(u32, *reo_timeout, 1 + remaining);
+                       /* Record maximum wait time */
+                       *reo_timeout = max_t(u32, *reo_timeout, remaining);
                }
        }
 }