add flag description to man page

Author: manedurphy

src/iperf3.1

@@ -233,6 +233,11 @@ restart the server after \fIn\fR seconds in case it gets stuck.  In
 one-off mode, this is the number of seconds the server will wait
 before exiting.
 .TP
+.BR --server-max-duration " "
+max time, in seconds, that an iperf client can run against the server.
+When the sum of the client's time and omit values exceeds the max duration set by the server
+or the client's time value is 0, the measurement is rejected.
+.TP
 .BR --server-bitrate-limit " \fIn\fR[KMGT]"
 set a limit on the server side, which will cause a test to abort if
 the client specifies a test of more than \fIn\fR bits per second, or

src/iperf_api.c

@@ -2253,7 +2253,7 @@ iperf_exchange_parameters(struct iperf_test *test)
         if (get_parameters(test) < 0)
             return -1;
 
-        if (test->max_server_duration > 0 && ((test->duration + test->omit) > test->max_server_duration) || test->duration == 0) {
+        if ((test->max_server_duration > 0) && (((test->duration + test->omit) > test->max_server_duration) || (test->duration == 0))) {
             if (iperf_set_send_state(test, SERVER_ERROR) != 0)
                 return -1;