From bea91172a914b0b135360d2b73401c60f738e9c1 Mon Sep 17 00:00:00 2001
From: Laurent MAZET <laurent.mazet@thalesgroup.com>
Date: Fri, 3 Oct 2025 17:40:21 +0200
Subject: [PATCH] add test for udp latency

---
 udp_lat.c          | 189 +++++++++++++++++++++++++++++++++++++++++++++
 udp.c => udp_rtt.c |   2 +-
 2 files changed, 190 insertions(+), 1 deletion(-)
 create mode 100644 udp_lat.c
 rename udp.c => udp_rtt.c (99%)

diff --git a/udp_lat.c b/udp_lat.c
new file mode 100644
index 0000000..2d7c744
--- /dev/null
+++ b/udp_lat.c
@@ -0,0 +1,189 @@
+/* depend: */
+/* cflags: */
+/* linker: mtime.o test.o stat.o -lm -lpthread -lrt */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <pthread.h>
+#include <unistd.h>
+
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/socket.h>
+
+#include "mtime.h"
+#include "test.h"
+
+/* global variables */
+
+dts_t *deltas = NULL;
+int nb_measurements = 0;
+
+int port = 1024;
+
+char *message = "UDP socket latency";
+
+void _usage_ext (FILE *fd)
+{
+    fprintf (fd, "... port\n");
+    fprintf (fd, " port: port number (%d)\n", port);
+}
+void (*usage_ext) (FILE *) = _usage_ext;
+
+int _parse_arg_ext (char *arg)
+{
+    static int narg = 0;
+
+    int rc = 0;
+    switch (narg) {
+    case 0: port = atoi (arg); if (port < 0) rc = 1; break;
+    default: rc = 1;
+    }
+    narg++;
+
+    return rc;
+}
+int (*parse_arg_ext) (char *) = _parse_arg_ext;
+
+#define MAXBUF 1024
+#define TIMER 1000
+
+pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
+ts_t ts1, ts2;
+int rc = 0;
+int localhost_ip = 0x7f000001;
+
+void *ping (__attribute__((unused)) void *arg)
+{
+
+    int sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (sock == -1) {
+        fprintf (stderr, "ping error: socket\n");
+        rc = 1;
+        pthread_exit (NULL);
+    }
+/*
+    struct sockaddr_in local = { 0 };
+    local.sin_family = AF_INET;
+    local.sin_port = htons (port);
+    local.sin_addr.s_addr = htonl (INADDR_ANY);
+
+    if (bind (sock, (struct sockaddr *)&local, sizeof (local)) == -1) {
+        fprintf (stderr, "ping error: bind\n");
+        rc = 1;
+        pthread_exit (NULL);
+    }
+*/
+    struct sockaddr_in remote = { 0 };
+    remote.sin_family = AF_INET;
+    remote.sin_port = htons (port);
+    remote.sin_addr.s_addr = htonl (localhost_ip);
+
+    printf ("Sending ping...\n");
+
+    pthread_mutex_unlock (&mutex);
+    usleep (TIMER);
+
+    for (int i = 0; i < nb_measurements; i++) {
+
+        char buffer[MAXBUF] = { 0 };
+        sprintf (buffer, "ping %d", i);
+
+        pthread_mutex_lock (&mutex);
+        pthread_mutex_unlock (&mutex);
+
+        sys_timestamp (&ts1);
+        if (sendto (sock, buffer, strlen (buffer) + 1, 0, (struct sockaddr *)&remote, sizeof (remote)) == -1) {
+            fprintf (stderr, "ping error: sendto (%d)\n", i);
+            rc = 1;
+            pthread_exit (NULL);
+        }
+
+        usleep (TIMER);
+    }
+
+    close (sock);
+
+    pthread_exit (NULL);
+}
+
+void *pong (__attribute__((unused)) void *arg)
+{
+
+    int sock = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (sock == -1) {
+        fprintf (stderr, "pong error: socket\n");
+        rc = 1;
+        pthread_exit (NULL);
+    }
+
+    struct sockaddr_in local = { 0 };
+    local.sin_family = AF_INET;
+    local.sin_port = htons (port);
+    local.sin_addr.s_addr = htonl (INADDR_ANY);
+
+    if (bind (sock, (struct sockaddr *)&local, sizeof (local)) == -1) {
+        fprintf (stderr, "pong error: bind\n");
+        rc = 1;
+        pthread_exit (NULL);
+    }
+
+    printf ("Sending pong...\n");
+
+    for (int i = 0; i < nb_measurements; i++) {
+
+        pthread_mutex_unlock (&mutex);
+
+        char buffer[MAXBUF] = { 0 };
+        if (recv (sock, buffer, MAXBUF, 0) == -1) {
+            fprintf (stderr, "pong error: recv_from (%d)\n", i);
+            rc = 1;
+            pthread_exit (NULL);
+        }
+        sys_timestamp (&ts2);
+        deltas[i] = diff_timestamp (&ts2, &ts1);
+
+        pthread_mutex_lock (&mutex);
+        usleep (TIMER);
+    }
+
+    close (sock);
+
+    pthread_exit (NULL);
+}
+
+int test (dts_t *buffer, int nb)
+{
+
+    /* set global variables */
+
+    deltas = buffer;
+    nb_measurements = nb;
+
+    /* udp socket test */
+
+    pthread_mutex_lock (&mutex);
+
+    pthread_t tid1;
+    if (pthread_create (&tid1, NULL, ping, NULL) != 0) {
+        fprintf (stderr, "error on pthread_create\n");
+        return 1;
+    }
+
+    pthread_mutex_lock (&mutex);
+
+    pthread_t tid2;
+    if (pthread_create (&tid2, NULL, pong, NULL) != 0) {
+        fprintf (stderr, "error on pthread_create\n");
+        return 1;
+    }
+
+    pthread_join (tid1, NULL);
+    pthread_join (tid2, NULL);
+
+    pthread_mutex_destroy (&mutex);
+
+    return rc;
+}
diff --git a/udp.c b/udp_rtt.c
similarity index 99%
rename from udp.c
rename to udp_rtt.c
index a66511a..de97b85 100644
--- a/udp.c
+++ b/udp_rtt.c
@@ -28,7 +28,7 @@ char *remote_host = "localhost";
 int remote_port = 1025;
 int mode = 0;
 
-char *message = "udp socket";
+char *message = "UDP socket RTT";
 
 void _usage_ext (FILE *fd)
 {
-- 
2.30.2