support fine timing interval and calculate std dev

2 files changed, 58 insertions, 17 deletions

diff --git a/sbin/ping/ping.8 b/sbin/ping/ping.8
index b2b82670151..f7e71ce2e98 100644
--- a/sbin/ping/ping.8
+++ b/sbin/ping/ping.8
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: ping.8,v 1.18 1999/06/04 02:45:22 aaron Exp $
+.\"	$OpenBSD: ping.8,v 1.19 1999/07/18 16:21:55 hugh Exp $
 .\"	$NetBSD: ping.8,v 1.10 1995/12/31 04:55:35 ghudson Exp $
 .\"
 .\" Copyright (c) 1985, 1991, 1993
@@ -115,6 +115,8 @@ Wait
 seconds
 between sending each packet .
 The default is to wait for one second between each packet.
+The wait time may be fractional, but only the super-user may specify
+a value less than one second.
 This option is incompatible with the
 .Fl f
 option.
@@ -209,9 +211,9 @@ Then, hosts and gateways further and further away should be
 Round trip times and packet loss statistics are computed.
 If duplicate packets are received, they are not included in the packet
 loss calculation, although the round trip time of these packets is used
-in calculating the minimum/average/maximum round trip time numbers.
-When the specified number of packets have been sent (and received), or
-if the program is terminated with a
+in calculating the minimum/average/maximum round trip time numbers and
+the standard deviation.  When the specified number of packets have been
+sent (and received), or if the program is terminated with a
 .Dv SIGINT ,
 a brief summary is displayed.
 .Pp
diff --git a/sbin/ping/ping.c b/sbin/ping/ping.c
index 1ce45a8c4fe..32774304eac 100644
--- a/sbin/ping/ping.c
+++ b/sbin/ping/ping.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ping.c,v 1.38 1999/02/24 21:02:41 kjell Exp $	*/
+/*	$OpenBSD: ping.c,v 1.39 1999/07/18 16:21:55 hugh Exp $	*/
 /*	$NetBSD: ping.c,v 1.20 1995/08/11 22:37:58 cgd Exp $	*/
 
 /*
@@ -47,7 +47,7 @@ static char copyright[] =
 #if 0
 static char sccsid[] = "@(#)ping.c	8.1 (Berkeley) 6/5/93";
 #else
-static char rcsid[] = "$OpenBSD: ping.c,v 1.38 1999/02/24 21:02:41 kjell Exp $";
+static char rcsid[] = "$OpenBSD: ping.c,v 1.39 1999/07/18 16:21:55 hugh Exp $";
 #endif
 #endif /* not lint */
 
@@ -155,7 +155,8 @@ 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 */
-int interval = 1;		/* interval between packets */
+double interval = 1;		/* interval between packets */
+struct itimerval interstr;	/* interval structure for use with setitimer */
 
 /* timing */
 int timing;			/* flag to do timing */
@@ -163,6 +164,7 @@ int maxwait = MAXWAIT_DEFAULT;	/* max seconds to wait for response */
 quad_t tmin = 999999999;	/* minimum round trip time in millisec */
 quad_t tmax = 0;		/* maximum round trip time in millisec */
 quad_t tsum = 0;		/* sum of all times in millisec, for doing average */
+quad_t tsumsq = 0;		/* sum of all times squared, for std. dev. */
 
 #ifdef SIGINFO
 int reset_kerninfo;
@@ -177,6 +179,7 @@ int check_icmph __P((struct ip *));
 void pr_icmph __P((struct icmp *));
 void pr_pack __P((char *, int, struct sockaddr_in *));
 void pr_retip __P((struct ip *));
+quad_t qsqrt __P((quad_t));
 void usage();
 
 int
@@ -246,9 +249,18 @@ main(argc, argv)
 			options |= F_SADDR;
 			break;
 		case 'i':		/* wait between sending packets */
-			interval = strtol(optarg, NULL, 0);
-			if (interval <= 0)
+			interval = strtod(optarg, NULL);
+
+			if (interval <= 0 || interval >= INT_MAX)
 				errx(1, "bad timing interval: %s", optarg);
+
+			if (interval < 1)
+				if (getuid())
+					errx(1, "%s: only root may use interval < 1s", strerror(EPERM));
+
+			if (interval < 0.01)
+				interval = 0.01;
+
 			options |= F_INTERVAL;
 			break;
 		case 'L':
@@ -315,6 +327,13 @@ main(argc, argv)
 
 	if (argc != 1)
 		usage();
+
+	memset(&interstr, 0, sizeof(interstr));
+
+	interstr.it_value.tv_sec = (long) interval;
+	interstr.it_value.tv_usec =
+		(long) ((interval - interstr.it_value.tv_sec) * 1000000);
+
 	target = *argv;
 
 	memset(&whereto, 0, sizeof(struct sockaddr));
@@ -525,7 +544,7 @@ catcher()
 	pinger();
 	(void)signal(SIGALRM, catcher);
 	if (!npackets || ntransmitted < npackets)
-		alarm((u_int)interval);
+		setitimer(ITIMER_REAL, &interstr, (struct itimerval *)0);
 	else {
 		if (nreceived) {
 			waittime = 2 * tmax / 1000000;
@@ -672,6 +691,7 @@ pr_pack(buf, cc, from)
 			timersub(&tv, &tp, &tv);
 			triptime = (tv.tv_sec * 1000000) + tv.tv_usec;
 			tsum += triptime;
+			tsumsq += triptime * triptime;
 			if (triptime < tmin)
 				tmin = triptime;
 			if (triptime > tmax)
@@ -877,8 +897,6 @@ void
 summary(header)
 	int header;
 {
-	quad_t	i;
-
 	(void)putchar('\r');
 	(void)fflush(stdout);
 
@@ -899,15 +917,36 @@ summary(header)
 	}
 	(void)putchar('\n');
 	if (nreceived && timing) {
-		/* Only display average to milliseconds */
-		i = tsum / (nreceived + nrepeats);
-		(void)printf("round-trip min/avg/max = %d.%03d/%d.%03d/%d.%03d ms\n",
+		quad_t num = nreceived + nrepeats;
+		quad_t avg = tsum / num;
+		quad_t dev = qsqrt(tsumsq / num - avg * avg);
+		(void)printf("round-trip min/avg/max/std-dev = "
+		    "%d.%03d/%d.%03d/%d.%03d/%d.%03d ms\n",
 		    (int)(tmin / 1000), (int)(tmin % 1000),
-		    (int)(i / 1000), (int)(i % 1000),
-		    (int)(tmax / 1000), (int)(tmax % 1000));
+		    (int)(avg  / 1000), (int)(avg  % 1000),
+		    (int)(tmax / 1000), (int)(tmax % 1000),
+		    (int)(dev  / 1000), (int)(dev  % 1000));
 	}
 }
 
+quad_t
+qsqrt(quad_t qdev)
+{
+	quad_t y, x = 1;
+
+	if (!qdev)
+		return(0);
+
+	do { /* newton was a stinker */
+		y = x;
+		x = qdev / x;
+		x += y;
+		x /= 2;
+	} while (x - y);
+
+	return(x);
+}
+
 /*
  * finish --
  *	Print out statistics, and give up.