[TCP]: Prevent reordering adjustments during FRTO

To be honest, I'm not too sure how the reord stuff works in the
first place but this seems necessary.

When FRTO has been active, the one and only retransmission could
be unnecessary but the state and sending order might not be what
the sacktag code expects it to be (to work correctly).

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 055721d8495e88f58dac096686da5238d09e1052..df516d4eca96de81152afa1bacd3936fcc84515a 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1224,7 +1224,8 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 
        tp->left_out = tp->sacked_out + tp->lost_out;
 
-       if ((reord < tp->fackets_out) && icsk->icsk_ca_state != TCP_CA_Loss)
+       if ((reord < tp->fackets_out) && icsk->icsk_ca_state != TCP_CA_Loss &&
+           (tp->frto_highmark && after(tp->snd_una, tp->frto_highmark)))
                tcp_update_reordering(sk, ((tp->fackets_out + 1) - reord), 0);
 
 #if FASTRETRANS_DEBUG > 0