1 files changed, 15 insertions, 2 deletions

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 9da9f19ece8a..f79a51607292 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -811,12 +811,25 @@ void tcp_update_metrics(struct sock *sk)
         }
 }
 
+/* Numbers are taken from RFC3390.
+ *
+ * John Heffner states:
+ *
+ *      The RFC specifies a window of no more than 4380 bytes
+ *      unless 2*MSS > 4380.  Reading the pseudocode in the RFC
+ *      is a bit misleading because they use a clamp at 4380 bytes
+ *      rather than use a multiplier in the relevant range.
+ */
 __u32 tcp_init_cwnd(struct tcp_sock *tp, struct dst_entry *dst)
 {
         __u32 cwnd = (dst ? dst_metric(dst, RTAX_INITCWND) : 0);
 
-        if (!cwnd)
-                cwnd = rfc3390_bytes_to_packets(tp->mss_cache);
+        if (!cwnd) {
+                if (tp->mss_cache > 1460)
+                        cwnd = 2;
+                else
+                        cwnd = (tp->mss_cache > 1095) ? 3 : 4;
+        }
         return min_t(__u32, cwnd, tp->snd_cwnd_clamp);
 }