tcp: disable RFC6675 loss detection
This patch disables RFC6675 loss detection and make sysctl
net.ipv4.tcp_recovery = 1 controls a binary choice between RACK
(1) or RFC6675 (0).
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Priyaranjan Jha <priyarjha@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index b188e0d..ccbe04f 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2035,6 +2035,11 @@ static inline int tcp_dupack_heuristics(const struct tcp_sock *tp)
return tp->sacked_out + 1;
}
+static bool tcp_is_rack(const struct sock *sk)
+{
+ return sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION;
+}
+
/* Linux NewReno/SACK/ECN state machine.
* --------------------------------------
*
@@ -2141,7 +2146,7 @@ static bool tcp_time_to_recover(struct sock *sk, int flag)
return true;
/* Not-A-Trick#2 : Classic rule... */
- if (tcp_dupack_heuristics(tp) > tp->reordering)
+ if (!tcp_is_rack(sk) && tcp_dupack_heuristics(tp) > tp->reordering)
return true;
return false;
@@ -2722,8 +2727,7 @@ static void tcp_rack_identify_loss(struct sock *sk, int *ack_flag)
{
struct tcp_sock *tp = tcp_sk(sk);
- /* Use RACK to detect loss */
- if (sock_net(sk)->ipv4.sysctl_tcp_recovery & TCP_RACK_LOSS_DETECTION) {
+ if (tcp_is_rack(sk)) {
u32 prior_retrans = tp->retrans_out;
tcp_rack_mark_lost(sk);
@@ -2862,7 +2866,7 @@ static void tcp_fastretrans_alert(struct sock *sk, const u32 prior_snd_una,
fast_rexmit = 1;
}
- if (do_lost)
+ if (!tcp_is_rack(sk) && do_lost)
tcp_update_scoreboard(sk, fast_rexmit);
*rexmit = REXMIT_LOST;
}