diff --git a/tools/gtp-link-add.c b/tools/gtp-link-add.c
index 833a3b2..3d893eb 100644
--- a/tools/gtp-link-add.c
+++ b/tools/gtp-link-add.c
@@ -1,3 +1,25 @@
+/* Command line utility to create GTP link */
+
+/* (C) 2014 by sysmocom - s.f.m.c. GmbH
+ * Author: Pablo Neira Ayuso <pablo@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * 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 Affero 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/>.
+ *
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <unistd.h>
diff --git a/tools/gtp-tunnel.c b/tools/gtp-tunnel.c
index 763ce53..9c52a27 100644
--- a/tools/gtp-tunnel.c
+++ b/tools/gtp-tunnel.c
@@ -1,3 +1,25 @@
+/* Command line utility to create GTP tunnels (PDP contexts) */
+
+/* (C) 2014 by sysmocom - s.f.m.c. GmbH
+ * Author: Pablo Neira Ayuso <pablo@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * 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 Affero 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/>.
+ *
+ */
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
diff --git a/tools/gtpnl.c b/tools/gtpnl.c
index 6b2f1e2..252f0b1 100644
--- a/tools/gtpnl.c
+++ b/tools/gtpnl.c
@@ -1,3 +1,25 @@
+/* Helper functions */
+
+/* (C) 2014 by sysmocom - s.f.m.c. GmbH
+ * Author: Pablo Neira Ayuso <pablo@gnumonks.org>
+ *
+ * All Rights Reserved
+ *
+ * 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 Affero 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/>.
+ *
+ */
+
 #include <stdint.h>
 #include <libmnl/libmnl.h>
 #include <linux/gtp_nl.h>