diff --git a/lib/nlattr.c b/lib/nlattr.c
index 927c2f1..3d8295c 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * NETLINK      Netlink attributes
  *