tcp: Properly count duplicated ACKs

diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 1ee3499..672b7f9 100644 (file)
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1907,7 +1907,8 @@ after_listen:
                                tcp_sack_update_scoreboard(tp, &to);
                        if (!tcp_callout_active(tp, tp->tt_rexmt) ||
                            th->th_ack != tp->snd_una) {
-                               tcpstat.tcps_rcvdupack++;
+                               if (tlen == 0 && tiwin == tp->snd_wnd)
+                                       tcpstat.tcps_rcvdupack++;
                                tp->t_dupacks = 0;
                                break;
                        }