Add Time Flag For The Iperf Server Process

src/iperf.h

@@ -293,6 +293,7 @@ struct iperf_test
     int       server_port;
     int       omit;                             /* duration of omit period (-O flag) */
     int       duration;                         /* total duration of test (-t flag) */
+    int       server_duration;                  /* maximum possible duration of test as enforced by the server (--server-time flag) */
     char     *diskfile_name;			/* -F option */
     int       affinity, server_affinity;	/* -A option */
 #if defined(HAVE_CPUSET_SETAFFINITY)

src/iperf_api.c

@@ -892,15 +892,15 @@ void
 iperf_on_test_start(struct iperf_test *test)
 {
     if (test->json_output) {
-	cJSON_AddItemToObject(test->json_start, "test_start", iperf_json_printf("protocol: %s  num_streams: %d  blksize: %d  omit: %d  duration: %d  bytes: %d  blocks: %d  reverse: %d  tos: %d  target_bitrate: %d bidir: %d fqrate: %d interval: %f", test->protocol->name, (int64_t) test->num_streams, (int64_t) test->settings->blksize, (int64_t) test->omit, (int64_t) test->duration, (int64_t) test->settings->bytes, (int64_t) test->settings->blocks, test->reverse?(int64_t)1:(int64_t)0, (int64_t) test->settings->tos, (int64_t) test->settings->rate, (int64_t) test->bidirectional, (uint64_t) test->settings->fqrate, test->stats_interval));
+	cJSON_AddItemToObject(test->json_start, "test_start", iperf_json_printf("protocol: %s  num_streams: %d  blksize: %d  omit: %d  duration: %d  server_duration: %d bytes: %d  blocks: %d  reverse: %d  tos: %d  target_bitrate: %d bidir: %d fqrate: %d interval: %f", test->protocol->name, (int64_t) test->num_streams, (int64_t) test->settings->blksize, (int64_t) test->omit, (int64_t) test->duration, (int64_t) test->server_duration, (int64_t) test->settings->bytes, (int64_t) test->settings->blocks, test->reverse?(int64_t)1:(int64_t)0, (int64_t) test->settings->tos, (int64_t) test->settings->rate, (int64_t) test->bidirectional, (uint64_t) test->settings->fqrate, test->stats_interval));
     } else {
 	if (test->verbose) {
 	    if (test->settings->bytes)
 		iperf_printf(test, test_start_bytes, test->protocol->name, test->num_streams, test->settings->blksize, test->omit, test->settings->bytes, test->settings->tos);
 	    else if (test->settings->blocks)
 		iperf_printf(test, test_start_blocks, test->protocol->name, test->num_streams, test->settings->blksize, test->omit, test->settings->blocks, test->settings->tos);
 	    else
-		iperf_printf(test, test_start_time, test->protocol->name, test->num_streams, test->settings->blksize, test->omit, test->duration, test->settings->tos);
+		iperf_printf(test, test_start_time, test->protocol->name, test->num_streams, test->settings->blksize, test->omit, (test->server_duration > 0 && test->duration > test->server_duration) ? test->server_duration : test->duration, test->settings->tos);
 	}
     }
     if (test->json_stream) {
@@ -1080,7 +1080,8 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
         {"udp", no_argument, NULL, 'u'},
         {"bitrate", required_argument, NULL, 'b'},
         {"bandwidth", required_argument, NULL, 'b'},
-	{"server-bitrate-limit", required_argument, NULL, OPT_SERVER_BITRATE_LIMIT},
+        {"server-bitrate-limit", required_argument, NULL, OPT_SERVER_BITRATE_LIMIT},
+        {"server-time", required_argument, NULL, OPT_SERVER_TIME},
         {"time", required_argument, NULL, 't'},
         {"bytes", required_argument, NULL, 'n'},
         {"blockcount", required_argument, NULL, 'k'},
@@ -1164,7 +1165,7 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
     int rcv_timeout_in = 0;
 
     blksize = 0;
-    server_flag = client_flag = rate_flag = duration_flag = rcv_timeout_flag = snd_timeout_flag =0;
+    server_flag = client_flag = rate_flag = duration_flag = rcv_timeout_flag = snd_timeout_flag = 0;
 #if defined(HAVE_SSL)
     char *client_username = NULL, *client_rsa_public_key = NULL, *server_rsa_private_key = NULL;
     FILE *ptr_file;
@@ -1312,6 +1313,14 @@ iperf_parse_arguments(struct iperf_test *test, int argc, char **argv)
 		test->settings->bitrate_limit = unit_atof_rate(optarg);
 		server_flag = 1;
 	        break;
+            case OPT_SERVER_TIME:
+        test->server_duration = atoi(optarg);
+        if (test->server_duration > MAX_TIME || test->server_duration < 0) {
+            i_errno = IEDURATION;
+            return -1;
+        }
+        server_flag = 1;
+        break;
             case 't':
                 test->duration = atoi(optarg);
                 if (test->duration > MAX_TIME || test->duration < 0) {
@@ -2929,6 +2938,7 @@ iperf_defaults(struct iperf_test *testp)
 
     testp->omit = OMIT;
     testp->duration = DURATION;
+    testp->server_duration = 0;
     testp->diskfile_name = (char*) 0;
     testp->affinity = -1;
     testp->server_affinity = -1;

src/iperf_api.h

@@ -101,6 +101,7 @@ typedef atomic_uint_fast64_t atomic_iperf_size_t;
 #define OPT_JSON_STREAM 28
 #define OPT_SND_TIMEOUT 29
 #define OPT_USE_PKCS1_PADDING 30
+#define OPT_SERVER_TIME 31
 
 /* states */
 #define TEST_START 1
@@ -475,6 +476,8 @@ enum {
     IEPTHREADJOIN=152,		// Unable to join thread (check perror)
     IEPTHREADATTRINIT=153,      // Unable to initialize thread attribute (check perror)
     IEPTHREADATTRDESTROY=154,      // Unable to destroy thread attribute (check perror)
+    IESENDSERVERDURATION=155, // Unable to send the server's maximum measurement duration
+    IERECVSERVERDURATION=156, // Unable to receive the server's maximum measurement duration
     /* Stream errors */
     IECREATESTREAM = 200,   // Unable to create a new stream (check herror/perror)
     IEINITSTREAM = 201,     // Unable to initialize stream (check herror/perror)

src/iperf_client_api.c

@@ -203,14 +203,26 @@ create_client_timers(struct iperf_test * test)
     }
     cd.p = test;
     test->timer = test->stats_timer = test->reporter_timer = NULL;
-    if (test->duration != 0) {
-	test->done = 0;
-        test->timer = tmr_create(&now, test_timer_proc, cd, ( test->duration + test->omit ) * SEC_TO_US, 0);
+
+    int duration = test->duration;
+    if (duration != 0) {
+        /**
+         * The duration of the measurement should only be overridden if it exceeds the duration set by the server or
+         * if no duration is set on the server.
+         * 
+         */
+        if (test->server_duration > 0 && test->server_duration < duration) {
+            duration = test->server_duration;
+        }
+
+        test->done = 0;
+        test->timer = tmr_create(&now, test_timer_proc, cd, (duration + test->omit) * SEC_TO_US, 0);
         if (test->timer == NULL) {
             i_errno = IEINITTEST;
             return -1;
-	}
+        }
     }
+
     if (test->stats_interval != 0) {
         test->stats_timer = tmr_create(&now, client_stats_timer_proc, cd, test->stats_interval * SEC_TO_US, 1);
         if (test->stats_timer == NULL) {
@@ -426,6 +438,18 @@ iperf_connect(struct iperf_test *test)
         return -1;
     }
 
+    /**
+     * If the server has a value set for the --server-time flag, the client will read it here and adjust its measurement time accordingly.
+     * If the value is 0, then the measurement will run for the duration that the client has set.
+     */
+    char server_duration_str[15] = "";
+    if (Nread(test->ctrl_sck, server_duration_str, sizeof(server_duration_str), Ptcp) != sizeof(server_duration_str))
+    {
+        i_errno = IERECVSERVERDURATION;
+        return -1;
+    }
+    test->server_duration = atoi(server_duration_str);
+
     FD_SET(test->ctrl_sck, &test->read_set);
     if (test->ctrl_sck > test->max_fd) test->max_fd = test->ctrl_sck;
 

src/iperf_locale.c

@@ -149,6 +149,8 @@ const char usage_longstr[] = "Usage: iperf3 [-s|-c host] [options]\n"
                            "  --time-skew-threshold     time skew threshold (in seconds) between the server\n"
                            "                            and client during the authentication process\n"
                            "  --use-pkcs1-padding       use pkcs1 padding at your own risk\n"
+                           "  --server-time             time in seconds to transmit for. selected when \n"
+                           "                            value is less than client's duration.\n"
 #endif //HAVE_SSL
                            "Client specific:\n"
                            "  -c, --client <host>[%%<dev>] run in client mode, connecting to <host>\n"

src/iperf_server_api.c

@@ -175,8 +175,23 @@ iperf_accept(struct iperf_test *test)
             i_errno = IERECVCOOKIE;
             goto error_handling;
         }
-    FD_SET(test->ctrl_sck, &test->read_set);
-    if (test->ctrl_sck > test->max_fd) test->max_fd = test->ctrl_sck;
+
+        /**
+         * If the server has a value set for the --server-time flag, send it to the client 
+         * so that it can adjust its measurement time accordingly. If the value was not set
+         * via the flag, then the client will see a value of 0, which means that the server
+         * does not have a maximum measurement time.
+         */
+        char server_duration_str[15] = "";
+        sprintf(server_duration_str, "%d", test->server_duration);
+
+        if (Nwrite(test->ctrl_sck, server_duration_str, sizeof(server_duration_str), Ptcp) < 0) {
+            i_errno = IESENDSERVERDURATION;
+            goto error_handling;
+        }
+
+	FD_SET(test->ctrl_sck, &test->read_set);
+	if (test->ctrl_sck > test->max_fd) test->max_fd = test->ctrl_sck;
 
     if (iperf_set_send_state(test, PARAM_EXCHANGE) != 0)
         goto error_handling;
@@ -340,9 +355,20 @@ create_server_timers(struct iperf_test * test)
     }
     cd.p = test;
     test->timer = test->stats_timer = test->reporter_timer = NULL;
-    if (test->duration != 0 ) {
+
+    int duration = test->duration;
+    if (duration != 0 ) {
+        /**
+         * The duration of the measurement should only be overridden if it exceeds the duration set by the server or
+         * if no duration is set on the server.
+         * 
+         */
+        if (test->server_duration > 0 && test->server_duration < duration) {
+            duration = test->server_duration;
+        }
+
         test->done = 0;
-        test->timer = tmr_create(&now, server_timer_proc, cd, (test->duration + test->omit + grace_period) * SEC_TO_US, 0);
+        test->timer = tmr_create(&now, server_timer_proc, cd, (duration + test->omit + grace_period) * SEC_TO_US, 0);
         if (test->timer == NULL) {
             i_errno = IEINITTEST;
             return -1;