The -A option (beep when packets are dropped) didn't work quite

right; after a single packet was dropped it beeped after every
transmission.

Change its implementation to only output a bell when there is an
increase in the maximum value of the number of packets that were
sent but not yet received. This has the benefit that even for very
long round-trip times, ping -A will do roughly the right thing
after a few inital false-positives.

Reviewed by:	ru

2 files changed, 12 insertions, 5 deletions

diff --git a/sbin/ping/ping.8 b/sbin/ping/ping.8
index 2d8110d75599..ef133e844680 100644
--- a/sbin/ping/ping.8
+++ b/sbin/ping/ping.8
@@ -32,7 +32,7 @@
 .\"     @(#)ping.8	8.2 (Berkeley) 12/11/93
 .\" $FreeBSD$
 .\"
-.Dd March 1, 1997
+.Dd September 25, 2001
 .Dt PING 8
 .Os
 .Sh NAME
@@ -81,11 +81,14 @@ bytes used to fill out the packet.  The options are as follows:
 .Bl -tag -width indent
 .It Fl A
 Audible.
-Include a bell
+Output a bell
 .Tn ( ASCII
 0x07)
-character in the output when no packet is received before the next packet
+character when no packet is received before the next packet
 is transmitted.
+To cater for round-trip times that are longer than the interval
+between transmissions, further missing packets cause a bell only
+if the maximum number of unreceived packets has increased.
 .It Fl a
 Audible.
 Include a bell
diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index 5840b8f70dda..0c6b3cbc32fd 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -163,6 +163,7 @@ long npackets;			/* max packets to transmit */
 long nreceived;			/* # of packets we got back */
 long nrepeats;			/* number of duplicates */
 long ntransmitted;		/* sequence # for outbound packets = #sent */
+long nmissedmax;		/* max value of ntransmitted - nreceived - 1 */
 int interval = 1000;		/* interval between packets, ms */
 
 /* timing */
@@ -706,8 +707,11 @@ main(argc, argv)
 			}
 			(void)gettimeofday(&last, NULL);
 
-			if (ntransmitted != nreceived+1 && options & F_MISSED)
-				(void)write(STDOUT_FILENO, &BBELL, 1);
+			if (ntransmitted - nreceived - 1 > nmissedmax) {
+				nmissedmax = ntransmitted - nreceived - 1;
+				if (options & F_MISSED)
+					(void)write(STDOUT_FILENO, &BBELL, 1);
+			}
 		}
 	}
 	finish();