diff --git a/library/DNS_Helpers.ttcn b/library/DNS_Helpers.ttcn
index 45c3a09..122adff 100644
--- a/library/DNS_Helpers.ttcn
+++ b/library/DNS_Helpers.ttcn
@@ -1,5 +1,15 @@
 module DNS_Helpers {
 
+/* DNS Helper functions in TTCN-3
+ * (C) 2018 Harald Welte <laforge@gnumonks.org>
+ * All rights reserved.
+ *
+ * Released under the terms of GNU General Public License, Version 2 or
+ * (at your option) any later version.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
 private function f_strchr(charstring s, char c) return integer {
 	var integer i;
 	for (i := 0; i < lengthof(s); i := i+1) {