diff --git a/control/controlclient/filter.go b/control/controlclient/filter.go
index a80e34ced..920f7619d 100644
--- a/control/controlclient/filter.go
+++ b/control/controlclient/filter.go
@@ -1,3 +1,7 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
 package controlclient
 
 import (