Moved, renamed, and deleted files

The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.

1 files changed, 1703 insertions, 0 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
new file mode 100644
index 00000000..a5fba177
--- /dev/null
+++ b/drivers/net/tun.c
@@ -0,0 +1,1703 @@
+/*
+ *  TUN - Universal TUN/TAP device driver.
+ *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.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.
+ *
+ *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
+ */
+
+/*
+ *  Changes:
+ *
+ *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
+ *    Add TUNSETLINK ioctl to set the link encapsulation
+ *
+ *  Mark Smith <markzzzsmith@yahoo.com.au>
+ *    Use random_ether_addr() for tap MAC address.
+ *
+ *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
+ *    Fixes in packet dropping, queue length setting and queue wakeup.
+ *    Increased default tx queue length.
+ *    Added ethtool API.
+ *    Minor cleanups
+ *
+ *  Daniel Podlejski <underley@underley.eu.org>
+ *    Modifications for 2.3.99-pre5 kernel.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#define DRV_NAME	"tun"
+#define DRV_VERSION	"1.6"
+#define DRV_DESCRIPTION	"Universal TUN/TAP device driver"
+#define DRV_COPYRIGHT	"(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/major.h>
+#include <linux/slab.h>
+#include <linux/poll.h>
+#include <linux/fcntl.h>
+#include <linux/init.h>
+#include <linux/skbuff.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/miscdevice.h>
+#include <linux/ethtool.h>
+#include <linux/rtnetlink.h>
+#include <linux/compat.h>
+#include <linux/if.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/if_tun.h>
+#include <linux/crc32.h>
+#include <linux/nsproxy.h>
+#include <linux/virtio_net.h>
+#include <linux/rcupdate.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+
+#include <asm/uaccess.h>
+
+/* Uncomment to enable debugging */
+/* #define TUN_DEBUG 1 */
+
+#ifdef TUN_DEBUG
+static int debug;
+
+#define tun_debug(level, tun, fmt, args...)			\
+do {								\
+	if (tun->debug)						\
+		netdev_printk(level, tun->dev, fmt, ##args);	\
+} while (0)
+#define DBG1(level, fmt, args...)				\
+do {								\
+	if (debug == 2)						\
+		printk(level fmt, ##args);			\
+} while (0)
+#else
+#define tun_debug(level, tun, fmt, args...)			\
+do {								\
+	if (0)							\
+		netdev_printk(level, tun->dev, fmt, ##args);	\
+} while (0)
+#define DBG1(level, fmt, args...)				\
+do {								\
+	if (0)							\
+		printk(level fmt, ##args);			\
+} while (0)
+#endif
+
+#define FLT_EXACT_COUNT 8
+struct tap_filter {
+	unsigned int    count;    /* Number of addrs. Zero means disabled */
+	u32             mask[2];  /* Mask of the hashed addrs */
+	unsigned char	addr[FLT_EXACT_COUNT][ETH_ALEN];
+};
+
+struct tun_file {
+	atomic_t count;
+	struct tun_struct *tun;
+	struct net *net;
+};
+
+struct tun_sock;
+
+struct tun_struct {
+	struct tun_file		*tfile;
+	unsigned int 		flags;
+	uid_t			owner;
+	gid_t			group;
+
+	struct net_device	*dev;
+	netdev_features_t	set_features;
+#define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
+			  NETIF_F_TSO6|NETIF_F_UFO)
+	struct fasync_struct	*fasync;
+
+	struct tap_filter       txflt;
+	struct socket		socket;
+	struct socket_wq	wq;
+
+	int			vnet_hdr_sz;
+
+#ifdef TUN_DEBUG
+	int debug;
+#endif
+};
+
+struct tun_sock {
+	struct sock		sk;
+	struct tun_struct	*tun;
+};
+
+static inline struct tun_sock *tun_sk(struct sock *sk)
+{
+	return container_of(sk, struct tun_sock, sk);
+}
+
+static int tun_attach(struct tun_struct *tun, struct file *file)
+{
+	struct tun_file *tfile = file->private_data;
+	int err;
+
+	ASSERT_RTNL();
+
+	netif_tx_lock_bh(tun->dev);
+
+	err = -EINVAL;
+	if (tfile->tun)
+		goto out;
+
+	err = -EBUSY;
+	if (tun->tfile)
+		goto out;
+
+	err = 0;
+	tfile->tun = tun;
+	tun->tfile = tfile;
+	tun->socket.file = file;
+	netif_carrier_on(tun->dev);
+	dev_hold(tun->dev);
+	sock_hold(tun->socket.sk);
+	atomic_inc(&tfile->count);
+
+out:
+	netif_tx_unlock_bh(tun->dev);
+	return err;
+}
+
+static void __tun_detach(struct tun_struct *tun)
+{
+	/* Detach from net device */
+	netif_tx_lock_bh(tun->dev);
+	netif_carrier_off(tun->dev);
+	tun->tfile = NULL;
+	tun->socket.file = NULL;
+	netif_tx_unlock_bh(tun->dev);
+
+	/* Drop read queue */
+	skb_queue_purge(&tun->socket.sk->sk_receive_queue);
+
+	/* Drop the extra count on the net device */
+	dev_put(tun->dev);
+}
+
+static void tun_detach(struct tun_struct *tun)
+{
+	rtnl_lock();
+	__tun_detach(tun);
+	rtnl_unlock();
+}
+
+static struct tun_struct *__tun_get(struct tun_file *tfile)
+{
+	struct tun_struct *tun = NULL;
+
+	if (atomic_inc_not_zero(&tfile->count))
+		tun = tfile->tun;
+
+	return tun;
+}
+
+static struct tun_struct *tun_get(struct file *file)
+{
+	return __tun_get(file->private_data);
+}
+
+static void tun_put(struct tun_struct *tun)
+{
+	struct tun_file *tfile = tun->tfile;
+
+	if (atomic_dec_and_test(&tfile->count))
+		tun_detach(tfile->tun);
+}
+
+/* TAP filtering */
+static void addr_hash_set(u32 *mask, const u8 *addr)
+{
+	int n = ether_crc(ETH_ALEN, addr) >> 26;
+	mask[n >> 5] |= (1 << (n & 31));
+}
+
+static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
+{
+	int n = ether_crc(ETH_ALEN, addr) >> 26;
+	return mask[n >> 5] & (1 << (n & 31));
+}
+
+static int update_filter(struct tap_filter *filter, void __user *arg)
+{
+	struct { u8 u[ETH_ALEN]; } *addr;
+	struct tun_filter uf;
+	int err, alen, n, nexact;
+
+	if (copy_from_user(&uf, arg, sizeof(uf)))
+		return -EFAULT;
+
+	if (!uf.count) {
+		/* Disabled */
+		filter->count = 0;
+		return 0;
+	}
+
+	alen = ETH_ALEN * uf.count;
+	addr = kmalloc(alen, GFP_KERNEL);
+	if (!addr)
+		return -ENOMEM;
+
+	if (copy_from_user(addr, arg + sizeof(uf), alen)) {
+		err = -EFAULT;
+		goto done;
+	}
+
+	/* The filter is updated without holding any locks. Which is
+	 * perfectly safe. We disable it first and in the worst
+	 * case we'll accept a few undesired packets. */
+	filter->count = 0;
+	wmb();
+
+	/* Use first set of addresses as an exact filter */
+	for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
+		memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
+
+	nexact = n;
+
+	/* Remaining multicast addresses are hashed,
+	 * unicast will leave the filter disabled. */
+	memset(filter->mask, 0, sizeof(filter->mask));
+	for (; n < uf.count; n++) {
+		if (!is_multicast_ether_addr(addr[n].u)) {
+			err = 0; /* no filter */
+			goto done;
+		}
+		addr_hash_set(filter->mask, addr[n].u);
+	}
+
+	/* For ALLMULTI just set the mask to all ones.
+	 * This overrides the mask populated above. */
+	if ((uf.flags & TUN_FLT_ALLMULTI))
+		memset(filter->mask, ~0, sizeof(filter->mask));
+
+	/* Now enable the filter */
+	wmb();
+	filter->count = nexact;
+
+	/* Return the number of exact filters */
+	err = nexact;
+
+done:
+	kfree(addr);
+	return err;
+}
+
+/* Returns: 0 - drop, !=0 - accept */
+static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
+{
+	/* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
+	 * at this point. */
+	struct ethhdr *eh = (struct ethhdr *) skb->data;
+	int i;
+
+	/* Exact match */
+	for (i = 0; i < filter->count; i++)
+		if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
+			return 1;
+
+	/* Inexact match (multicast only) */
+	if (is_multicast_ether_addr(eh->h_dest))
+		return addr_hash_test(filter->mask, eh->h_dest);
+
+	return 0;
+}
+
+/*
+ * Checks whether the packet is accepted or not.
+ * Returns: 0 - drop, !=0 - accept
+ */
+static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
+{
+	if (!filter->count)
+		return 1;
+
+	return run_filter(filter, skb);
+}
+
+/* Network device part of the driver */
+
+static const struct ethtool_ops tun_ethtool_ops;
+
+/* Net device detach from fd. */
+static void tun_net_uninit(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	struct tun_file *tfile = tun->tfile;
+
+	/* Inform the methods they need to stop using the dev.
+	 */
+	if (tfile) {
+		wake_up_all(&tun->wq.wait);
+		if (atomic_dec_and_test(&tfile->count))
+			__tun_detach(tun);
+	}
+}
+
+static void tun_free_netdev(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	sk_release_kernel(tun->socket.sk);
+}
+
+/* Net device open. */
+static int tun_net_open(struct net_device *dev)
+{
+	netif_start_queue(dev);
+	return 0;
+}
+
+/* Net device close. */
+static int tun_net_close(struct net_device *dev)
+{
+	netif_stop_queue(dev);
+	return 0;
+}
+
+/* Net device start xmit */
+static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
+
+	/* Drop packet if interface is not attached */
+	if (!tun->tfile)
+		goto drop;
+
+	/* Drop if the filter does not like it.
+	 * This is a noop if the filter is disabled.
+	 * Filter can be enabled only for the TAP devices. */
+	if (!check_filter(&tun->txflt, skb))
+		goto drop;
+
+	if (tun->socket.sk->sk_filter &&
+	    sk_filter(tun->socket.sk, skb))
+		goto drop;
+
+	if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
+		if (!(tun->flags & TUN_ONE_QUEUE)) {
+			/* Normal queueing mode. */
+			/* Packet scheduler handles dropping of further packets. */
+			netif_stop_queue(dev);
+
+			/* We won't see all dropped packets individually, so overrun
+			 * error is more appropriate. */
+			dev->stats.tx_fifo_errors++;
+		} else {
+			/* Single queue mode.
+			 * Driver handles dropping of all packets itself. */
+			goto drop;
+		}
+	}
+
+	/* Orphan the skb - required as we might hang on to it
+	 * for indefinite time. */
+	skb_orphan(skb);
+
+	/* Enqueue packet */
+	skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
+
+	/* Notify and wake up reader process */
+	if (tun->flags & TUN_FASYNC)
+		kill_fasync(&tun->fasync, SIGIO, POLL_IN);
+	wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
+				   POLLRDNORM | POLLRDBAND);
+	return NETDEV_TX_OK;
+
+drop:
+	dev->stats.tx_dropped++;
+	kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static void tun_net_mclist(struct net_device *dev)
+{
+	/*
+	 * This callback is supposed to deal with mc filter in
+	 * _rx_ path and has nothing to do with the _tx_ path.
+	 * In rx path we always accept everything userspace gives us.
+	 */
+}
+
+#define MIN_MTU 68
+#define MAX_MTU 65535
+
+static int
+tun_net_change_mtu(struct net_device *dev, int new_mtu)
+{
+	if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
+		return -EINVAL;
+	dev->mtu = new_mtu;
+	return 0;
+}
+
+static netdev_features_t tun_net_fix_features(struct net_device *dev,
+	netdev_features_t features)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
+}
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void tun_poll_controller(struct net_device *dev)
+{
+	/*
+	 * Tun only receives frames when:
+	 * 1) the char device endpoint gets data from user space
+	 * 2) the tun socket gets a sendmsg call from user space
+	 * Since both of those are syncronous operations, we are guaranteed
+	 * never to have pending data when we poll for it
+	 * so theres nothing to do here but return.
+	 * We need this though so netpoll recognizes us as an interface that
+	 * supports polling, which enables bridge devices in virt setups to
+	 * still use netconsole
+	 */
+	return;
+}
+#endif
+static const struct net_device_ops tun_netdev_ops = {
+	.ndo_uninit		= tun_net_uninit,
+	.ndo_open		= tun_net_open,
+	.ndo_stop		= tun_net_close,
+	.ndo_start_xmit		= tun_net_xmit,
+	.ndo_change_mtu		= tun_net_change_mtu,
+	.ndo_fix_features	= tun_net_fix_features,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	.ndo_poll_controller	= tun_poll_controller,
+#endif
+};
+
+static const struct net_device_ops tap_netdev_ops = {
+	.ndo_uninit		= tun_net_uninit,
+	.ndo_open		= tun_net_open,
+	.ndo_stop		= tun_net_close,
+	.ndo_start_xmit		= tun_net_xmit,
+	.ndo_change_mtu		= tun_net_change_mtu,
+	.ndo_fix_features	= tun_net_fix_features,
+	.ndo_set_rx_mode	= tun_net_mclist,
+	.ndo_set_mac_address	= eth_mac_addr,
+	.ndo_validate_addr	= eth_validate_addr,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	.ndo_poll_controller	= tun_poll_controller,
+#endif
+};
+
+/* Initialize net device. */
+static void tun_net_init(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	switch (tun->flags & TUN_TYPE_MASK) {
+	case TUN_TUN_DEV:
+		dev->netdev_ops = &tun_netdev_ops;
+
+		/* Point-to-Point TUN Device */
+		dev->hard_header_len = 0;
+		dev->addr_len = 0;
+		dev->mtu = 1500;
+
+		/* Zero header length */
+		dev->type = ARPHRD_NONE;
+		dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
+		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
+		break;
+
+	case TUN_TAP_DEV:
+		dev->netdev_ops = &tap_netdev_ops;
+		/* Ethernet TAP Device */
+		ether_setup(dev);
+		dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+
+		eth_hw_addr_random(dev);
+
+		dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
+		break;
+	}
+}
+
+/* Character device part */
+
+/* Poll */
+static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
+{
+	struct tun_file *tfile = file->private_data;
+	struct tun_struct *tun = __tun_get(tfile);
+	struct sock *sk;
+	unsigned int mask = 0;
+
+	if (!tun)
+		return POLLERR;
+
+	sk = tun->socket.sk;
+
+	tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
+
+	poll_wait(file, &tun->wq.wait, wait);
+
+	if (!skb_queue_empty(&sk->sk_receive_queue))
+		mask |= POLLIN | POLLRDNORM;
+
+	if (sock_writeable(sk) ||
+	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
+	     sock_writeable(sk)))
+		mask |= POLLOUT | POLLWRNORM;
+
+	if (tun->dev->reg_state != NETREG_REGISTERED)
+		mask = POLLERR;
+
+	tun_put(tun);
+	return mask;
+}
+
+/* prepad is the amount to reserve at front.  len is length after that.
+ * linear is a hint as to how much to copy (usually headers). */
+static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
+				     size_t prepad, size_t len,
+				     size_t linear, int noblock)
+{
+	struct sock *sk = tun->socket.sk;
+	struct sk_buff *skb;
+	int err;
+
+	sock_update_classid(sk);
+
+	/* Under a page?  Don't bother with paged skb. */
+	if (prepad + len < PAGE_SIZE || !linear)
+		linear = len;
+
+	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
+				   &err);
+	if (!skb)
+		return ERR_PTR(err);
+
+	skb_reserve(skb, prepad);
+	skb_put(skb, linear);
+	skb->data_len = len - linear;
+	skb->len += len - linear;
+
+	return skb;
+}
+
+/* Get packet from user space buffer */
+static ssize_t tun_get_user(struct tun_struct *tun,
+			    const struct iovec *iv, size_t count,
+			    int noblock)
+{
+	struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
+	struct sk_buff *skb;
+	size_t len = count, align = NET_SKB_PAD;
+	struct virtio_net_hdr gso = { 0 };
+	int offset = 0;
+
+	if (!(tun->flags & TUN_NO_PI)) {
+		if ((len -= sizeof(pi)) > count)
+			return -EINVAL;
+
+		if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
+			return -EFAULT;
+		offset += sizeof(pi);
+	}
+
+	if (tun->flags & TUN_VNET_HDR) {
+		if ((len -= tun->vnet_hdr_sz) > count)
+			return -EINVAL;
+
+		if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
+			return -EFAULT;
+
+		if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+		    gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
+			gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
+
+		if (gso.hdr_len > len)
+			return -EINVAL;
+		offset += tun->vnet_hdr_sz;
+	}
+
+	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
+		align += NET_IP_ALIGN;
+		if (unlikely(len < ETH_HLEN ||
+			     (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
+			return -EINVAL;
+	}
+
+	skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
+	if (IS_ERR(skb)) {
+		if (PTR_ERR(skb) != -EAGAIN)
+			tun->dev->stats.rx_dropped++;
+		return PTR_ERR(skb);
+	}
+
+	if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
+		tun->dev->stats.rx_dropped++;
+		kfree_skb(skb);
+		return -EFAULT;
+	}
+
+	if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+		if (!skb_partial_csum_set(skb, gso.csum_start,
+					  gso.csum_offset)) {
+			tun->dev->stats.rx_frame_errors++;
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+	}
+
+	switch (tun->flags & TUN_TYPE_MASK) {
+	case TUN_TUN_DEV:
+		if (tun->flags & TUN_NO_PI) {
+			switch (skb->data[0] & 0xf0) {
+			case 0x40:
+				pi.proto = htons(ETH_P_IP);
+				break;
+			case 0x60:
+				pi.proto = htons(ETH_P_IPV6);
+				break;
+			default:
+				tun->dev->stats.rx_dropped++;
+				kfree_skb(skb);
+				return -EINVAL;
+			}
+		}
+
+		skb_reset_mac_header(skb);
+		skb->protocol = pi.proto;
+		skb->dev = tun->dev;
+		break;
+	case TUN_TAP_DEV:
+		skb->protocol = eth_type_trans(skb, tun->dev);
+		break;
+	}
+
+	if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+		pr_debug("GSO!\n");
+		switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+		case VIRTIO_NET_HDR_GSO_TCPV4:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+			break;
+		case VIRTIO_NET_HDR_GSO_TCPV6:
+			skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+			break;
+		case VIRTIO_NET_HDR_GSO_UDP:
+			skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
+			break;
+		default:
+			tun->dev->stats.rx_frame_errors++;
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+
+		if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
+			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
+
+		skb_shinfo(skb)->gso_size = gso.gso_size;
+		if (skb_shinfo(skb)->gso_size == 0) {
+			tun->dev->stats.rx_frame_errors++;
+			kfree_skb(skb);
+			return -EINVAL;
+		}
+
+		/* Header must be checked, and gso_segs computed. */
+		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+		skb_shinfo(skb)->gso_segs = 0;
+	}
+
+	netif_rx_ni(skb);
+
+	tun->dev->stats.rx_packets++;
+	tun->dev->stats.rx_bytes += len;
+
+	return count;
+}
+
+static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
+			      unsigned long count, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct tun_struct *tun = tun_get(file);
+	ssize_t result;
+
+	if (!tun)
+		return -EBADFD;
+
+	tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
+
+	result = tun_get_user(tun, iv, iov_length(iv, count),
+			      file->f_flags & O_NONBLOCK);
+
+	tun_put(tun);
+	return result;
+}
+
+/* Put packet to the user space buffer */
+static ssize_t tun_put_user(struct tun_struct *tun,
+			    struct sk_buff *skb,
+			    const struct iovec *iv, int len)
+{
+	struct tun_pi pi = { 0, skb->protocol };
+	ssize_t total = 0;
+
+	if (!(tun->flags & TUN_NO_PI)) {
+		if ((len -= sizeof(pi)) < 0)
+			return -EINVAL;
+
+		if (len < skb->len) {
+			/* Packet will be striped */
+			pi.flags |= TUN_PKT_STRIP;
+		}
+
+		if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
+			return -EFAULT;
+		total += sizeof(pi);
+	}
+
+	if (tun->flags & TUN_VNET_HDR) {
+		struct virtio_net_hdr gso = { 0 }; /* no info leak */
+		if ((len -= tun->vnet_hdr_sz) < 0)
+			return -EINVAL;
+
+		if (skb_is_gso(skb)) {
+			struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+			/* This is a hint as to how much should be linear. */
+			gso.hdr_len = skb_headlen(skb);
+			gso.gso_size = sinfo->gso_size;
+			if (sinfo->gso_type & SKB_GSO_TCPV4)
+				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+			else if (sinfo->gso_type & SKB_GSO_TCPV6)
+				gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+			else if (sinfo->gso_type & SKB_GSO_UDP)
+				gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
+			else {
+				pr_err("unexpected GSO type: "
+				       "0x%x, gso_size %d, hdr_len %d\n",
+				       sinfo->gso_type, gso.gso_size,
+				       gso.hdr_len);
+				print_hex_dump(KERN_ERR, "tun: ",
+					       DUMP_PREFIX_NONE,
+					       16, 1, skb->head,
+					       min((int)gso.hdr_len, 64), true);
+				WARN_ON_ONCE(1);
+				return -EINVAL;
+			}
+			if (sinfo->gso_type & SKB_GSO_TCP_ECN)
+				gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+		} else
+			gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+		if (skb->ip_summed == CHECKSUM_PARTIAL) {
+			gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+			gso.csum_start = skb_checksum_start_offset(skb);
+			gso.csum_offset = skb->csum_offset;
+		} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
+			gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
+		} /* else everything is zero */
+
+		if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
+					       sizeof(gso))))
+			return -EFAULT;
+		total += tun->vnet_hdr_sz;
+	}
+
+	len = min_t(int, skb->len, len);
+
+	skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
+	total += skb->len;
+
+	tun->dev->stats.tx_packets++;
+	tun->dev->stats.tx_bytes += len;
+
+	return total;
+}
+
+static ssize_t tun_do_read(struct tun_struct *tun,
+			   struct kiocb *iocb, const struct iovec *iv,
+			   ssize_t len, int noblock)
+{
+	DECLARE_WAITQUEUE(wait, current);
+	struct sk_buff *skb;
+	ssize_t ret = 0;
+
+	tun_debug(KERN_INFO, tun, "tun_chr_read\n");
+
+	if (unlikely(!noblock))
+		add_wait_queue(&tun->wq.wait, &wait);
+	while (len) {
+		current->state = TASK_INTERRUPTIBLE;
+
+		/* Read frames from the queue */
+		if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
+			if (noblock) {
+				ret = -EAGAIN;
+				break;
+			}
+			if (signal_pending(current)) {
+				ret = -ERESTARTSYS;
+				break;
+			}
+			if (tun->dev->reg_state != NETREG_REGISTERED) {
+				ret = -EIO;
+				break;
+			}
+
+			/* Nothing to read, let's sleep */
+			schedule();
+			continue;
+		}
+		netif_wake_queue(tun->dev);
+
+		ret = tun_put_user(tun, skb, iv, len);
+		kfree_skb(skb);
+		break;
+	}
+
+	current->state = TASK_RUNNING;
+	if (unlikely(!noblock))
+		remove_wait_queue(&tun->wq.wait, &wait);
+
+	return ret;
+}
+
+static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
+			    unsigned long count, loff_t pos)
+{
+	struct file *file = iocb->ki_filp;
+	struct tun_file *tfile = file->private_data;
+	struct tun_struct *tun = __tun_get(tfile);
+	ssize_t len, ret;
+
+	if (!tun)
+		return -EBADFD;
+	len = iov_length(iv, count);
+	if (len < 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
+	ret = min_t(ssize_t, ret, len);
+out:
+	tun_put(tun);
+	return ret;
+}
+
+static void tun_setup(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	tun->owner = -1;
+	tun->group = -1;
+
+	dev->ethtool_ops = &tun_ethtool_ops;
+	dev->destructor = tun_free_netdev;
+}
+
+/* Trivial set of netlink ops to allow deleting tun or tap
+ * device with netlink.
+ */
+static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
+{
+	return -EINVAL;
+}
+
+static struct rtnl_link_ops tun_link_ops __read_mostly = {
+	.kind		= DRV_NAME,
+	.priv_size	= sizeof(struct tun_struct),
+	.setup		= tun_setup,
+	.validate	= tun_validate,
+};
+
+static void tun_sock_write_space(struct sock *sk)
+{
+	struct tun_struct *tun;
+	wait_queue_head_t *wqueue;
+
+	if (!sock_writeable(sk))
+		return;
+
+	if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+		return;
+
+	wqueue = sk_sleep(sk);
+	if (wqueue && waitqueue_active(wqueue))
+		wake_up_interruptible_sync_poll(wqueue, POLLOUT |
+						POLLWRNORM | POLLWRBAND);
+
+	tun = tun_sk(sk)->tun;
+	kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
+}
+
+static void tun_sock_destruct(struct sock *sk)
+{
+	free_netdev(tun_sk(sk)->tun->dev);
+}
+
+static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
+		       struct msghdr *m, size_t total_len)
+{
+	struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
+	return tun_get_user(tun, m->msg_iov, total_len,
+			    m->msg_flags & MSG_DONTWAIT);
+}
+
+static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
+		       struct msghdr *m, size_t total_len,
+		       int flags)
+{
+	struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
+	int ret;
+	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
+		return -EINVAL;
+	ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
+			  flags & MSG_DONTWAIT);
+	if (ret > total_len) {
+		m->msg_flags |= MSG_TRUNC;
+		ret = flags & MSG_TRUNC ? ret : total_len;
+	}
+	return ret;
+}
+
+static int tun_release(struct socket *sock)
+{
+	if (sock->sk)
+		sock_put(sock->sk);
+	return 0;
+}
+
+/* Ops structure to mimic raw sockets with tun */
+static const struct proto_ops tun_socket_ops = {
+	.sendmsg = tun_sendmsg,
+	.recvmsg = tun_recvmsg,
+	.release = tun_release,
+};
+
+static struct proto tun_proto = {
+	.name		= "tun",
+	.owner		= THIS_MODULE,
+	.obj_size	= sizeof(struct tun_sock),
+};
+
+static int tun_flags(struct tun_struct *tun)
+{
+	int flags = 0;
+
+	if (tun->flags & TUN_TUN_DEV)
+		flags |= IFF_TUN;
+	else
+		flags |= IFF_TAP;
+
+	if (tun->flags & TUN_NO_PI)
+		flags |= IFF_NO_PI;
+
+	if (tun->flags & TUN_ONE_QUEUE)
+		flags |= IFF_ONE_QUEUE;
+
+	if (tun->flags & TUN_VNET_HDR)
+		flags |= IFF_VNET_HDR;
+
+	return flags;
+}
+
+static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
+	return sprintf(buf, "0x%x\n", tun_flags(tun));
+}
+
+static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
+	return sprintf(buf, "%d\n", tun->owner);
+}
+
+static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct tun_struct *tun = netdev_priv(to_net_dev(dev));
+	return sprintf(buf, "%d\n", tun->group);
+}
+
+static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
+static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
+static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
+
+static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
+{
+	struct sock *sk;
+	struct tun_struct *tun;
+	struct net_device *dev;
+	int err;
+
+	dev = __dev_get_by_name(net, ifr->ifr_name);
+	if (dev) {
+		const struct cred *cred = current_cred();
+
+		if (ifr->ifr_flags & IFF_TUN_EXCL)
+			return -EBUSY;
+		if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
+			tun = netdev_priv(dev);
+		else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
+			tun = netdev_priv(dev);
+		else
+			return -EINVAL;
+
+		if (((tun->owner != -1 && cred->euid != tun->owner) ||
+		     (tun->group != -1 && !in_egroup_p(tun->group))) &&
+		    !capable(CAP_NET_ADMIN))
+			return -EPERM;
+		err = security_tun_dev_attach(tun->socket.sk);
+		if (err < 0)
+			return err;
+
+		err = tun_attach(tun, file);
+		if (err < 0)
+			return err;
+	}
+	else {
+		char *name;
+		unsigned long flags = 0;
+
+		if (!capable(CAP_NET_ADMIN))
+			return -EPERM;
+		err = security_tun_dev_create();
+		if (err < 0)
+			return err;
+
+		/* Set dev type */
+		if (ifr->ifr_flags & IFF_TUN) {
+			/* TUN device */
+			flags |= TUN_TUN_DEV;
+			name = "tun%d";
+		} else if (ifr->ifr_flags & IFF_TAP) {
+			/* TAP device */
+			flags |= TUN_TAP_DEV;
+			name = "tap%d";
+		} else
+			return -EINVAL;
+
+		if (*ifr->ifr_name)
+			name = ifr->ifr_name;
+
+		dev = alloc_netdev(sizeof(struct tun_struct), name,
+				   tun_setup);
+		if (!dev)
+			return -ENOMEM;
+
+		dev_net_set(dev, net);
+		dev->rtnl_link_ops = &tun_link_ops;
+
+		tun = netdev_priv(dev);
+		tun->dev = dev;
+		tun->flags = flags;
+		tun->txflt.count = 0;
+		tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
+
+		err = -ENOMEM;
+		sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
+		if (!sk)
+			goto err_free_dev;
+
+		sk_change_net(sk, net);
+		tun->socket.wq = &tun->wq;
+		init_waitqueue_head(&tun->wq.wait);
+		tun->socket.ops = &tun_socket_ops;
+		sock_init_data(&tun->socket, sk);
+		sk->sk_write_space = tun_sock_write_space;
+		sk->sk_sndbuf = INT_MAX;
+
+		tun_sk(sk)->tun = tun;
+
+		security_tun_dev_post_create(sk);
+
+		tun_net_init(dev);
+
+		dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
+			TUN_USER_FEATURES;
+		dev->features = dev->hw_features;
+
+		err = register_netdevice(tun->dev);
+		if (err < 0)
+			goto err_free_sk;
+
+		if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
+		    device_create_file(&tun->dev->dev, &dev_attr_owner) ||
+		    device_create_file(&tun->dev->dev, &dev_attr_group))
+			pr_err("Failed to create tun sysfs files\n");
+
+		sk->sk_destruct = tun_sock_destruct;
+
+		err = tun_attach(tun, file);
+		if (err < 0)
+			goto failed;
+	}
+
+	tun_debug(KERN_INFO, tun, "tun_set_iff\n");
+
+	if (ifr->ifr_flags & IFF_NO_PI)
+		tun->flags |= TUN_NO_PI;
+	else
+		tun->flags &= ~TUN_NO_PI;
+
+	if (ifr->ifr_flags & IFF_ONE_QUEUE)
+		tun->flags |= TUN_ONE_QUEUE;
+	else
+		tun->flags &= ~TUN_ONE_QUEUE;
+
+	if (ifr->ifr_flags & IFF_VNET_HDR)
+		tun->flags |= TUN_VNET_HDR;
+	else
+		tun->flags &= ~TUN_VNET_HDR;
+
+	/* Make sure persistent devices do not get stuck in
+	 * xoff state.
+	 */
+	if (netif_running(tun->dev))
+		netif_wake_queue(tun->dev);
+
+	strcpy(ifr->ifr_name, tun->dev->name);
+	return 0;
+
+ err_free_sk:
+	tun_free_netdev(dev);
+ err_free_dev:
+	free_netdev(dev);
+ failed:
+	return err;
+}
+
+static int tun_get_iff(struct net *net, struct tun_struct *tun,
+		       struct ifreq *ifr)
+{
+	tun_debug(KERN_INFO, tun, "tun_get_iff\n");
+
+	strcpy(ifr->ifr_name, tun->dev->name);
+
+	ifr->ifr_flags = tun_flags(tun);
+
+	return 0;
+}
+
+/* This is like a cut-down ethtool ops, except done via tun fd so no
+ * privs required. */
+static int set_offload(struct tun_struct *tun, unsigned long arg)
+{
+	netdev_features_t features = 0;
+
+	if (arg & TUN_F_CSUM) {
+		features |= NETIF_F_HW_CSUM;
+		arg &= ~TUN_F_CSUM;
+
+		if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
+			if (arg & TUN_F_TSO_ECN) {
+				features |= NETIF_F_TSO_ECN;
+				arg &= ~TUN_F_TSO_ECN;
+			}
+			if (arg & TUN_F_TSO4)
+				features |= NETIF_F_TSO;
+			if (arg & TUN_F_TSO6)
+				features |= NETIF_F_TSO6;
+			arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
+		}
+
+		if (arg & TUN_F_UFO) {
+			features |= NETIF_F_UFO;
+			arg &= ~TUN_F_UFO;
+		}
+	}
+
+	/* This gives the user a way to test for new features in future by
+	 * trying to set them. */
+	if (arg)
+		return -EINVAL;
+
+	tun->set_features = features;
+	netdev_update_features(tun->dev);
+
+	return 0;
+}
+
+static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
+			    unsigned long arg, int ifreq_len)
+{
+	struct tun_file *tfile = file->private_data;
+	struct tun_struct *tun;
+	void __user* argp = (void __user*)arg;
+	struct sock_fprog fprog;
+	struct ifreq ifr;
+	int sndbuf;
+	int vnet_hdr_sz;
+	int ret;
+
+#ifdef CONFIG_ANDROID_PARANOID_NETWORK
+	if (cmd != TUNGETIFF && !capable(CAP_NET_ADMIN)) {
+		return -EPERM;
+	}
+#endif
+
+	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
+		if (copy_from_user(&ifr, argp, ifreq_len))
+			return -EFAULT;
+
+	if (cmd == TUNGETFEATURES) {
+		/* Currently this just means: "what IFF flags are valid?".
+		 * This is needed because we never checked for invalid flags on
+		 * TUNSETIFF. */
+		return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
+				IFF_VNET_HDR,
+				(unsigned int __user*)argp);
+	}
+
+	rtnl_lock();
+
+	tun = __tun_get(tfile);
+	if (cmd == TUNSETIFF && !tun) {
+		ifr.ifr_name[IFNAMSIZ-1] = '\0';
+
+		ret = tun_set_iff(tfile->net, file, &ifr);
+
+		if (ret)
+			goto unlock;
+
+		if (copy_to_user(argp, &ifr, ifreq_len))
+			ret = -EFAULT;
+		goto unlock;
+	}
+
+	ret = -EBADFD;
+	if (!tun)
+		goto unlock;
+
+	tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
+
+	ret = 0;
+	switch (cmd) {
+	case TUNGETIFF:
+		ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
+		if (ret)
+			break;
+
+		if (copy_to_user(argp, &ifr, ifreq_len))
+			ret = -EFAULT;
+		break;
+
+	case TUNSETNOCSUM:
+		/* Disable/Enable checksum */
+
+		/* [unimplemented] */
+		tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
+			  arg ? "disabled" : "enabled");
+		break;
+
+	case TUNSETPERSIST:
+		/* Disable/Enable persist mode */
+		if (arg)
+			tun->flags |= TUN_PERSIST;
+		else
+			tun->flags &= ~TUN_PERSIST;
+
+		tun_debug(KERN_INFO, tun, "persist %s\n",
+			  arg ? "enabled" : "disabled");
+		break;
+
+	case TUNSETOWNER:
+		/* Set owner of the device */
+		tun->owner = (uid_t) arg;
+
+		tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner);
+		break;
+
+	case TUNSETGROUP:
+		/* Set group of the device */
+		tun->group= (gid_t) arg;
+
+		tun_debug(KERN_INFO, tun, "group set to %d\n", tun->group);
+		break;
+
+	case TUNSETLINK:
+		/* Only allow setting the type when the interface is down */
+		if (tun->dev->flags & IFF_UP) {
+			tun_debug(KERN_INFO, tun,
+				  "Linktype set failed because interface is up\n");
+			ret = -EBUSY;
+		} else {
+			tun->dev->type = (int) arg;
+			tun_debug(KERN_INFO, tun, "linktype set to %d\n",
+				  tun->dev->type);
+			ret = 0;
+		}
+		break;
+
+#ifdef TUN_DEBUG
+	case TUNSETDEBUG:
+		tun->debug = arg;
+		break;
+#endif
+	case TUNSETOFFLOAD:
+		ret = set_offload(tun, arg);
+		break;
+
+	case TUNSETTXFILTER:
+		/* Can be set only for TAPs */
+		ret = -EINVAL;
+		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
+			break;
+		ret = update_filter(&tun->txflt, (void __user *)arg);
+		break;
+
+	case SIOCGIFHWADDR:
+		/* Get hw address */
+		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
+		ifr.ifr_hwaddr.sa_family = tun->dev->type;
+		if (copy_to_user(argp, &ifr, ifreq_len))
+			ret = -EFAULT;
+		break;
+
+	case SIOCSIFHWADDR:
+		/* Set hw address */
+		tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
+			  ifr.ifr_hwaddr.sa_data);
+
+		ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
+		break;
+
+	case TUNGETSNDBUF:
+		sndbuf = tun->socket.sk->sk_sndbuf;
+		if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
+			ret = -EFAULT;
+		break;
+
+	case TUNSETSNDBUF:
+		if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
+			ret = -EFAULT;
+			break;
+		}
+
+		tun->socket.sk->sk_sndbuf = sndbuf;
+		break;
+
+	case TUNGETVNETHDRSZ:
+		vnet_hdr_sz = tun->vnet_hdr_sz;
+		if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
+			ret = -EFAULT;
+		break;
+
+	case TUNSETVNETHDRSZ:
+		if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
+			ret = -EFAULT;
+			break;
+		}
+		if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
+			ret = -EINVAL;
+			break;
+		}
+
+		tun->vnet_hdr_sz = vnet_hdr_sz;
+		break;
+
+	case TUNATTACHFILTER:
+		/* Can be set only for TAPs */
+		ret = -EINVAL;
+		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
+			break;
+		ret = -EFAULT;
+		if (copy_from_user(&fprog, argp, sizeof(fprog)))
+			break;
+
+		ret = sk_attach_filter(&fprog, tun->socket.sk);
+		break;
+
+	case TUNDETACHFILTER:
+		/* Can be set only for TAPs */
+		ret = -EINVAL;
+		if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
+			break;
+		ret = sk_detach_filter(tun->socket.sk);
+		break;
+
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+unlock:
+	rtnl_unlock();
+	if (tun)
+		tun_put(tun);
+	return ret;
+}
+
+static long tun_chr_ioctl(struct file *file,
+			  unsigned int cmd, unsigned long arg)
+{
+	return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
+}
+
+#ifdef CONFIG_COMPAT
+static long tun_chr_compat_ioctl(struct file *file,
+			 unsigned int cmd, unsigned long arg)
+{
+	switch (cmd) {
+	case TUNSETIFF:
+	case TUNGETIFF:
+	case TUNSETTXFILTER:
+	case TUNGETSNDBUF:
+	case TUNSETSNDBUF:
+	case SIOCGIFHWADDR:
+	case SIOCSIFHWADDR:
+		arg = (unsigned long)compat_ptr(arg);
+		break;
+	default:
+		arg = (compat_ulong_t)arg;
+		break;
+	}
+
+	/*
+	 * compat_ifreq is shorter than ifreq, so we must not access beyond
+	 * the end of that structure. All fields that are used in this
+	 * driver are compatible though, we don't need to convert the
+	 * contents.
+	 */
+	return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
+}
+#endif /* CONFIG_COMPAT */
+
+static int tun_chr_fasync(int fd, struct file *file, int on)
+{
+	struct tun_struct *tun = tun_get(file);
+	int ret;
+
+	if (!tun)
+		return -EBADFD;
+
+	tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
+
+	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
+		goto out;
+
+	if (on) {
+		ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
+		if (ret)
+			goto out;
+		tun->flags |= TUN_FASYNC;
+	} else
+		tun->flags &= ~TUN_FASYNC;
+	ret = 0;
+out:
+	tun_put(tun);
+	return ret;
+}
+
+static int tun_chr_open(struct inode *inode, struct file * file)
+{
+	struct tun_file *tfile;
+
+	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
+
+	tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
+	if (!tfile)
+		return -ENOMEM;
+	atomic_set(&tfile->count, 0);
+	tfile->tun = NULL;
+	tfile->net = get_net(current->nsproxy->net_ns);
+	file->private_data = tfile;
+	return 0;
+}
+
+static int tun_chr_close(struct inode *inode, struct file *file)
+{
+	struct tun_file *tfile = file->private_data;
+	struct tun_struct *tun;
+
+	tun = __tun_get(tfile);
+	if (tun) {
+		struct net_device *dev = tun->dev;
+
+		tun_debug(KERN_INFO, tun, "tun_chr_close\n");
+
+		__tun_detach(tun);
+
+		/* If desirable, unregister the netdevice. */
+		if (!(tun->flags & TUN_PERSIST)) {
+			rtnl_lock();
+			if (dev->reg_state == NETREG_REGISTERED)
+				unregister_netdevice(dev);
+			rtnl_unlock();
+		}
+	}
+
+	tun = tfile->tun;
+	if (tun)
+		sock_put(tun->socket.sk);
+
+	put_net(tfile->net);
+	kfree(tfile);
+
+	return 0;
+}
+
+static const struct file_operations tun_fops = {
+	.owner	= THIS_MODULE,
+	.llseek = no_llseek,
+	.read  = do_sync_read,
+	.aio_read  = tun_chr_aio_read,
+	.write = do_sync_write,
+	.aio_write = tun_chr_aio_write,
+	.poll	= tun_chr_poll,
+	.unlocked_ioctl	= tun_chr_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl = tun_chr_compat_ioctl,
+#endif
+	.open	= tun_chr_open,
+	.release = tun_chr_close,
+	.fasync = tun_chr_fasync
+};
+
+static struct miscdevice tun_miscdev = {
+	.minor = TUN_MINOR,
+	.name = "tun",
+	.nodename = "net/tun",
+	.fops = &tun_fops,
+};
+
+/* ethtool interface */
+
+static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+	cmd->supported		= 0;
+	cmd->advertising	= 0;
+	ethtool_cmd_speed_set(cmd, SPEED_10);
+	cmd->duplex		= DUPLEX_FULL;
+	cmd->port		= PORT_TP;
+	cmd->phy_address	= 0;
+	cmd->transceiver	= XCVR_INTERNAL;
+	cmd->autoneg		= AUTONEG_DISABLE;
+	cmd->maxtxpkt		= 0;
+	cmd->maxrxpkt		= 0;
+	return 0;
+}
+
+static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
+	strlcpy(info->version, DRV_VERSION, sizeof(info->version));
+
+	switch (tun->flags & TUN_TYPE_MASK) {
+	case TUN_TUN_DEV:
+		strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
+		break;
+	case TUN_TAP_DEV:
+		strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
+		break;
+	}
+}
+
+static u32 tun_get_msglevel(struct net_device *dev)
+{
+#ifdef TUN_DEBUG
+	struct tun_struct *tun = netdev_priv(dev);
+	return tun->debug;
+#else
+	return -EOPNOTSUPP;
+#endif
+}
+
+static void tun_set_msglevel(struct net_device *dev, u32 value)
+{
+#ifdef TUN_DEBUG
+	struct tun_struct *tun = netdev_priv(dev);
+	tun->debug = value;
+#endif
+}
+
+static const struct ethtool_ops tun_ethtool_ops = {
+	.get_settings	= tun_get_settings,
+	.get_drvinfo	= tun_get_drvinfo,
+	.get_msglevel	= tun_get_msglevel,
+	.set_msglevel	= tun_set_msglevel,
+	.get_link	= ethtool_op_get_link,
+};
+
+
+static int __init tun_init(void)
+{
+	int ret = 0;
+
+	pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
+	pr_info("%s\n", DRV_COPYRIGHT);
+
+	ret = rtnl_link_register(&tun_link_ops);
+	if (ret) {
+		pr_err("Can't register link_ops\n");
+		goto err_linkops;
+	}
+
+	ret = misc_register(&tun_miscdev);
+	if (ret) {
+        int i;
+        for(i=0;i<100;i++)
+		    pr_err("Can't register misc device %d\n", TUN_MINOR);
+		goto err_misc;
+	}
+	return  0;
+err_misc:
+	rtnl_link_unregister(&tun_link_ops);
+err_linkops:
+	return ret;
+}
+
+static void tun_cleanup(void)
+{
+	misc_deregister(&tun_miscdev);
+	rtnl_link_unregister(&tun_link_ops);
+}
+
+/* Get an underlying socket object from tun file.  Returns error unless file is
+ * attached to a device.  The returned object works like a packet socket, it
+ * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
+ * holding a reference to the file for as long as the socket is in use. */
+struct socket *tun_get_socket(struct file *file)
+{
+	struct tun_struct *tun;
+	if (file->f_op != &tun_fops)
+		return ERR_PTR(-EINVAL);
+	tun = tun_get(file);
+	if (!tun)
+		return ERR_PTR(-EBADFD);
+	tun_put(tun);
+	return &tun->socket;
+}
+EXPORT_SYMBOL_GPL(tun_get_socket);
+
+module_init(tun_init);
+module_exit(tun_cleanup);
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_AUTHOR(DRV_COPYRIGHT);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(TUN_MINOR);
+MODULE_ALIAS("devname:net/tun");