Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/if_tun.h b/include/linux/if_tun.h
index 3d2996d..5bda8cf 100644
--- a/include/linux/if_tun.h
+++ b/include/linux/if_tun.h
@@ -1,24 +1,29 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
 /*
  *  Universal TUN/TAP device driver.
  *  Copyright (C) 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com>
- *
- *  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 General Public License for more details.
  */
 #ifndef __IF_TUN_H
 #define __IF_TUN_H
 
 #include <uapi/linux/if_tun.h>
+#include <uapi/linux/virtio_net.h>
 
 #define TUN_XDP_FLAG 0x1UL
 
+#define TUN_MSG_UBUF 1
+#define TUN_MSG_PTR  2
+struct tun_msg_ctl {
+	unsigned short type;
+	unsigned short num;
+	void *ptr;
+};
+
+struct tun_xdp_hdr {
+	int buflen;
+	struct virtio_net_hdr gso;
+};
+
 #if defined(CONFIG_TUN) || defined(CONFIG_TUN_MODULE)
 struct socket *tun_get_socket(struct file *);
 struct ptr_ring *tun_get_tx_ring(struct file *file);