4 files changed, 5 insertions, 0 deletions
diff --git a/sys/netinet/tcp_input.c b/sys/netinet/tcp_input.c
index 0fb62e0..64cbed9 100644
--- a/sys/netinet/tcp_input.c
+++ b/sys/netinet/tcp_input.c
@@ -1785,6 +1785,7 @@ process_ACK:
 		 * we left off.
 		 */
 		if (tp->t_rxtshift == 1 && ticks < tp->t_badrxtwin) {
+			++tcpstat.tcps_sndrexmitbad;
 			tp->snd_cwnd = tp->snd_cwnd_prev;
 			tp->snd_ssthresh = tp->snd_ssthresh_prev;
 			tp->snd_nxt = tp->snd_max;
diff --git a/sys/netinet/tcp_reass.c b/sys/netinet/tcp_reass.c
index 0fb62e0..64cbed9 100644
--- a/sys/netinet/tcp_reass.c
+++ b/sys/netinet/tcp_reass.c
@@ -1785,6 +1785,7 @@ process_ACK:
 		 * we left off.
 		 */
 		if (tp->t_rxtshift == 1 && ticks < tp->t_badrxtwin) {
+			++tcpstat.tcps_sndrexmitbad;
 			tp->snd_cwnd = tp->snd_cwnd_prev;
 			tp->snd_ssthresh = tp->snd_ssthresh_prev;
 			tp->snd_nxt = tp->snd_max;
diff --git a/sys/netinet/tcp_var.h b/sys/netinet/tcp_var.h
index a58bdf5..51f9ae0 100644
--- a/sys/netinet/tcp_var.h
+++ b/sys/netinet/tcp_var.h
@@ -310,6 +310,7 @@ struct	tcpstat {
 	u_long	tcps_sndbyte;		/* data bytes sent */
 	u_long	tcps_sndrexmitpack;	/* data packets retransmitted */
 	u_long	tcps_sndrexmitbyte;	/* data bytes retransmitted */
+	u_long	tcps_sndrexmitbad;	/* unnecessary packet retransmissions */
 	u_long	tcps_sndacks;		/* ack-only packets sent */
 	u_long	tcps_sndprobe;		/* window probes sent */
 	u_long	tcps_sndurg;		/* packets sent with URG only */
diff --git a/usr.bin/netstat/inet.c b/usr.bin/netstat/inet.c
index b95bad7..f72fa98 100644
--- a/usr.bin/netstat/inet.c
+++ b/usr.bin/netstat/inet.c
@@ -381,6 +381,8 @@ tcp_stats(u_long off __unused, char *name, int af __unused)
 		"\t\t%lu data packet%s (%lu byte%s)\n");
 	p2(tcps_sndrexmitpack, tcps_sndrexmitbyte,
 		"\t\t%lu data packet%s (%lu byte%s) retransmitted\n");
+	p(tcps_sndrexmitbad,
+		"\t\t%lu data packet%s unnecessarily retransmitted\n");
 	p(tcps_mturesent, "\t\t%lu resend%s initiated by MTU discovery\n");
 	p2a(tcps_sndacks, tcps_delack,
 		"\t\t%lu ack-only packet%s (%lu delayed)\n");