diff --git a/src/error_format.h b/src/error_format.h
index 9fea079..9736456 100644
--- a/src/error_format.h
+++ b/src/error_format.h
@@ -1,3 +1,20 @@
+/*
+    Copyright (C) 2018 Open Networking Foundation
+
+    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 3 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, see <http://www.gnu.org/licenses/>.
+*/
+
 #ifndef OPENOLT_ERROR_FORMAT_H_
 #define OPENOLT_ERROR_FORMAT_H_