[TCP]: Allow minimum RTO to be configurable via routing metrics.

[karo-tx-linux.git] / net / ipv4 / tcp_input.c

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9785df37a65feeb285bc2f656eb828216de23585..1ee72127462bf37ed5ef834ebc71111b1cf070d5 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -555,6 +555,16 @@ static void tcp_event_data_recv(struct sock *sk, struct sk_buff *skb)
                tcp_grow_window(sk, skb);
 }
 
+static u32 tcp_rto_min(struct sock *sk)
+{
+       struct dst_entry *dst = __sk_dst_get(sk);
+       u32 rto_min = TCP_RTO_MIN;
+
+       if (dst_metric_locked(dst, RTAX_RTO_MIN))
+               rto_min = dst->metrics[RTAX_RTO_MIN-1];
+       return rto_min;
+}
+
 /* Called to compute a smoothed rtt estimate. The data fed to this
  * routine either comes from timestamps, or from segments that were
  * known _not_ to have been retransmitted [see Karn/Partridge
@@ -616,13 +626,13 @@ static void tcp_rtt_estimator(struct sock *sk, const __u32 mrtt)
                        if (tp->mdev_max < tp->rttvar)
                                tp->rttvar -= (tp->rttvar-tp->mdev_max)>>2;
                        tp->rtt_seq = tp->snd_nxt;
-                       tp->mdev_max = TCP_RTO_MIN;
+                       tp->mdev_max = tcp_rto_min(sk);
                }
        } else {
                /* no previous measure. */
                tp->srtt = m<<3;        /* take the measured time to be rtt */
                tp->mdev = m<<1;        /* make sure rto = 3*rtt */
-               tp->mdev_max = tp->rttvar = max(tp->mdev, TCP_RTO_MIN);
+               tp->mdev_max = tp->rttvar = max(tp->mdev, tcp_rto_min(sk));
                tp->rtt_seq = tp->snd_nxt;
        }
 }