diff --git a/tun.h b/tun.h
new file mode 100644
index 0000000..9ccb037
--- /dev/null
+++ b/tun.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * tun.h - tun device functions
+ */
+#ifndef __TUN_H__
+#define __TUN_H__
+
+struct tun_data {
+  char device4[IFNAMSIZ];
+  int read_fd6, write_fd6, fd4;
+};
+
+int set_nonblocking(int fd);
+int tun_open();
+int tun_alloc(char *dev, int fd);
+
+#endif