r4764 - developers/werner/owping
werner at docs.openmoko.org
werner at docs.openmoko.org
Fri Nov 7 04:37:30 CET 2008
Author: werner
Date: 2008-11-07 04:37:29 +0100 (Fri, 07 Nov 2008)
New Revision: 4764
Added:
developers/werner/owping/README
Modified:
developers/werner/owping/Makefile
developers/werner/owping/owping.c
developers/werner/owping/rx.c
developers/werner/owping/tx.c
Log:
- added README with a list of known issues
- receiver prints ping-like latency statistics at the end
- sender supports -c count option, like ping
- sender properly shuts down the receiver if failing or stopped with SIGINT
Modified: developers/werner/owping/Makefile
===================================================================
--- developers/werner/owping/Makefile 2008-11-07 01:15:33 UTC (rev 4763)
+++ developers/werner/owping/Makefile 2008-11-07 03:37:29 UTC (rev 4764)
@@ -1,6 +1,7 @@
CC=arm-angstrom-linux-gnueabi-gcc
CFLAGS=-Wall -Wshadow -g -O
+LDFLAGS=-lm
PREFIX=/usr
Added: developers/werner/owping/README
===================================================================
--- developers/werner/owping/README (rev 0)
+++ developers/werner/owping/README 2008-11-07 03:37:29 UTC (rev 4764)
@@ -0,0 +1,39 @@
+owping - One-way ping (UDP)
+===========================
+
+owping sends small UDP packets to determine the one-way latency and,
+indirectly, the one-way jitter.
+
+
+Usage
+-----
+
+Receiver:
+
+% owping
+
+Sender:
+
+% owping [-c count] ip_address
+
+
+Known issues
+------------
+
+- accuracy of latency measurements depends on precisely synchronized system
+ clocks on both sides (this is fundamentally unavoidable)
+
+- jitter measurements include application delays in the sending owping.
+ Should increase CPU priority.
+
+- even better jitter measurements may be possible if the sender includes
+ the time between transmissions in the packet data and the receiver
+ compares this with the inter-arrival time it measures.
+
+- receiver should also handle SIGINT, and print statistics
+
+- receiver should count gaps in the sequence numbers
+
+- should support host name resolution
+
+- should support setting the port number
Modified: developers/werner/owping/owping.c
===================================================================
--- developers/werner/owping/owping.c 2008-11-07 01:15:33 UTC (rev 4763)
+++ developers/werner/owping/owping.c 2008-11-07 03:37:29 UTC (rev 4764)
@@ -14,6 +14,7 @@
#include <stdlib.h>
#include <stdio.h>
+#include <unistd.h>
#include <arpa/inet.h>
#include "owping.h"
@@ -24,7 +25,7 @@
static void usage(const char *name)
{
- fprintf(stderr, "usage: %s [ip_address]\n", name);
+ fprintf(stderr, "usage: %s [[-c count] ip_address]\n", name);
exit(1);
}
@@ -32,18 +33,32 @@
int main(int argc, char **argv)
{
struct sockaddr_in addr;
+ int count = -1;
+ int c;
+ char *end;
- switch (argc) {
- case 1:
+ while ((c = getopt(argc, argv, "c:")) != EOF)
+ switch (c) {
+ case 'c':
+ count = strtoul(optarg, &end, 10);
+ if (*end)
+ usage(*argv);
+ break;
+ default:
+ usage(*argv);
+ }
+
+ switch (argc-optind) {
+ case 0:
rx(PORT);
break;
- case 2:
+ case 1:
addr.sin_family = AF_INET;
- addr.sin_addr.s_addr = inet_addr(argv[1]);
+ addr.sin_addr.s_addr = inet_addr(argv[optind]);
addr.sin_port = htons(PORT);
if (addr.sin_addr.s_addr == (in_addr_t) -1)
usage(*argv);
- tx(addr, 100);
+ tx(addr, count);
break;
default:
usage(*argv);
Modified: developers/werner/owping/rx.c
===================================================================
--- developers/werner/owping/rx.c 2008-11-07 01:15:33 UTC (rev 4763)
+++ developers/werner/owping/rx.c 2008-11-07 03:37:29 UTC (rev 4764)
@@ -14,6 +14,8 @@
#include <stdlib.h>
#include <stdio.h>
+#include <string.h>
+#include <math.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
@@ -22,18 +24,62 @@
#include "owping.h"
-static void delta(struct timeval t0, struct timeval t1)
+struct stats {
+ long min, max;
+ double sum, sq;
+ int n;
+};
+
+
+static void stats_init(struct stats *stats)
{
+ memset(stats, 0, sizeof(*stats));
+}
+
+
+static void stats_print(const char *label, const struct stats *stats)
+{
+ double avg = stats->sum/stats->n;
+
+ printf("%s min/avg/max/sdev = %.3f/%.3f/%.3f/%.3f ms (%d packets)\n",
+ label,
+ stats->min/1000.0, avg/1000.0, stats->max/1000.0,
+ sqrt(stats->sq/stats->n-avg*avg)/1000.0,
+ stats->n);
+}
+
+
+static void delta(struct timeval t0, struct timeval t1, struct stats *stats)
+{
+ char sign = ' ';
long us;
us = t1.tv_usec-t0.tv_usec;
us += (t1.tv_sec-t0.tv_sec)*1000000;
- printf(" %ld.%03ldms", us/1000, us % 1000);
+
+ if (!stats->n) {
+ stats->min = stats->max = us;
+ } else {
+ if (stats->min > us)
+ stats->min = us;
+ if (stats->max < us)
+ stats->max = us;
+ }
+ stats->n++;
+ stats->sum += us;
+ stats->sq += (double) us*us;
+
+ if (us < 0) {
+ us = -us;
+ sign = '-';
+ }
+ printf(" %c%ld.%03ldms", sign, us/1000, us % 1000);
}
void rx(int port)
{
+ struct stats stats_itf, stats_user;
struct sockaddr_in addr;
int s;
@@ -51,7 +97,8 @@
exit(1);
}
- // setsockopt timestamp
+ stats_init(&stats_itf);
+ stats_init(&stats_user);
while (1) {
struct owping buf;
@@ -67,7 +114,7 @@
exit(1);
}
if (got == 1)
- return;
+ break;
if (got != sizeof(buf)) {
fprintf(stderr, "bad read: expected %u, got %u\n",
(unsigned) sizeof(buf), (unsigned) got);
@@ -85,8 +132,11 @@
inet_ntoa(addr.sin_addr));
t_src.tv_sec = ntohl(buf.tv_sec);
t_src.tv_usec = ntohl(buf.tv_usec);
- delta(t_src, t_itf);
- delta(t_src, t_user);
+ delta(t_src, t_itf, &stats_itf);
+ delta(t_src, t_user, &stats_user);
putchar('\n');
}
+ stats_print("itf:", &stats_itf);
+ stats_print("app:", &stats_user);
+
}
Modified: developers/werner/owping/tx.c
===================================================================
--- developers/werner/owping/tx.c 2008-11-07 01:15:33 UTC (rev 4763)
+++ developers/werner/owping/tx.c 2008-11-07 03:37:29 UTC (rev 4764)
@@ -15,6 +15,7 @@
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
+#include <signal.h>
#include <sys/time.h>
#include <sys/socket.h>
#include <arpa/inet.h>
@@ -22,10 +23,26 @@
#include "owping.h"
+static int s;
+
+
+static void cleanup(void)
+{
+ write(s, "", 1);
+}
+
+
+static void handler(int sig)
+{
+ cleanup();
+ _exit(0);
+}
+
+
void tx(struct sockaddr_in addr, int num)
{
ssize_t sent;
- int s, seq;
+ int seq;
s = socket(PF_INET, SOCK_DGRAM, 0);
if (s < 0) {
@@ -38,7 +55,16 @@
exit(1);
}
- for (seq = 0; seq != num; seq++) {
+ if (atexit(cleanup)) {
+ perror("atexit");
+ exit(1);
+ }
+ if (signal(SIGINT, handler) == SIG_ERR) {
+ perror("signal(SIGINT)");
+ exit(1);
+ }
+
+ for (seq = 0; num < 0 || seq != num; seq++) {
struct owping buf;
struct timeval now;
@@ -63,14 +89,4 @@
exit(1);
}
}
-
- sent = write(s, "", 1);
- if (sent < 0) {
- perror("write");
- exit(1);
- }
- if (sent != 1) {
- fprintf(stderr, "bad write: %u < 1\n", (unsigned) sent);
- exit(1);
- }
}
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