Fix mistakes in server.c

packet-exchange/src/server.c

@@ -162,7 +162,7 @@ int main(int argc, char *argv[]) {
 static void process_options(int argc, char *argv[], thread_param_t *param,
                             main_param_t *main_param) {
   for (;;) {
-    int c = getopt(argc, argv, "abd:p:r:");
+    int c = getopt(argc, argv, "abd:f:p:r:");
 
     if (c == -1) break;
 
@@ -194,5 +194,11 @@ static void process_options(int argc, char *argv[], thread_param_t *param,
         break;
     }
   }
+
+  if (argc != optind + 1) {
+    printf("Usage: %s client_ip\n", argv[0]);
+    exit(EXIT_FAILURE);
+  }
+  param->ip_address = argv[optind];
 }