diff --git a/src/diag_gsm.c b/src/diag_gsm.c
index a2d0ea4..b05f6ca 100644
--- a/src/diag_gsm.c
+++ b/src/diag_gsm.c
@@ -1,3 +1,22 @@
+/* Utlity code for GSM related logging */
+/*
+ * (C) 2013-2016 by Harald Welte <laforge@gnumonks.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
 #include <osmocom/core/utils.h>
 #include <osmocom/core/msgb.h>