1 files changed, 883 insertions, 0 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
new file mode 100644
index 000000000000..7bfee366297b
--- /dev/null
+++ b/drivers/net/tun.c
@@ -0,0 +1,883 @@
+/*
+ *  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:
+ *
+ *  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 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/config.h>
+#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/if.h>
+#include <linux/if_arp.h>
+#include <linux/if_ether.h>
+#include <linux/if_tun.h>
+#include <linux/crc32.h>
+
+#include <asm/system.h>
+#include <asm/uaccess.h>
+
+#ifdef TUN_DEBUG
+static int debug;
+#endif
+
+/* Network device part of the driver */
+
+static LIST_HEAD(tun_dev_list);
+static struct ethtool_ops tun_ethtool_ops;
+
+/* 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 int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
+
+	/* Drop packet if interface is not attached */
+	if (!tun->attached)
+		goto drop;
+
+	/* Packet dropping */
+	if (skb_queue_len(&tun->readq) >= 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. */
+			tun->stats.tx_fifo_errors++;
+		} else {
+			/* Single queue mode.
+			 * Driver handles dropping of all packets itself. */
+			goto drop;
+		}
+	}
+
+	/* Queue packet */
+	skb_queue_tail(&tun->readq, skb);
+	dev->trans_start = jiffies;
+
+	/* Notify and wake up reader process */
+	if (tun->flags & TUN_FASYNC)
+		kill_fasync(&tun->fasync, SIGIO, POLL_IN);
+	wake_up_interruptible(&tun->read_wait);
+	return 0;
+
+drop:
+	tun->stats.tx_dropped++;
+	kfree_skb(skb);
+	return 0;
+}
+
+/** Add the specified Ethernet address to this multicast filter. */
+static void
+add_multi(u32* filter, const u8* addr)
+{
+	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
+	filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
+}
+
+/** Remove the specified Ethernet addres from this multicast filter. */
+static void
+del_multi(u32* filter, const u8* addr)
+{
+	int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
+	filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31));
+}
+
+/** Update the list of multicast groups to which the network device belongs.
+ * This list is used to filter packets being sent from the character device to
+ * the network device. */
+static void
+tun_net_mclist(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	const struct dev_mc_list *mclist;
+	int i;
+	DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
+			dev->name, dev->mc_count);
+	memset(tun->chr_filter, 0, sizeof tun->chr_filter);
+	for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
+			i++, mclist = mclist->next) {
+		add_multi(tun->net_filter, mclist->dmi_addr);
+		DBG(KERN_DEBUG "%s: tun_net_mclist: %x:%x:%x:%x:%x:%x\n",
+				dev->name,
+				mclist->dmi_addr[0], mclist->dmi_addr[1], mclist->dmi_addr[2],
+				mclist->dmi_addr[3], mclist->dmi_addr[4], mclist->dmi_addr[5]);
+	}
+}
+
+static struct net_device_stats *tun_net_stats(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	return &tun->stats;
+}
+
+/* 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:
+		/* 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:
+		/* Ethernet TAP Device */
+		dev->set_multicast_list = tun_net_mclist;
+
+		ether_setup(dev);
+		random_ether_addr(dev->dev_addr);
+		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_struct *tun = file->private_data;
+	unsigned int mask = POLLOUT | POLLWRNORM;
+
+	if (!tun)
+		return -EBADFD;
+
+	DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
+
+	poll_wait(file, &tun->read_wait, wait);
+ 
+	if (skb_queue_len(&tun->readq))
+		mask |= POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+/* Get packet from user space buffer */
+static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
+{
+	struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
+	struct sk_buff *skb;
+	size_t len = count, align = 0;
+
+	if (!(tun->flags & TUN_NO_PI)) {
+		if ((len -= sizeof(pi)) > count)
+			return -EINVAL;
+
+		if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
+			return -EFAULT;
+	}
+
+	if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
+		align = NET_IP_ALIGN;
+ 
+	if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
+		tun->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+
+	if (align)
+		skb_reserve(skb, align);
+	if (memcpy_fromiovec(skb_put(skb, len), iv, len))
+		return -EFAULT;
+
+	skb->dev = tun->dev;
+	switch (tun->flags & TUN_TYPE_MASK) {
+	case TUN_TUN_DEV:
+		skb->mac.raw = skb->data;
+		skb->protocol = pi.proto;
+		break;
+	case TUN_TAP_DEV:
+		skb->protocol = eth_type_trans(skb, tun->dev);
+		break;
+	};
+
+	if (tun->flags & TUN_NOCHECKSUM)
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+ 
+	netif_rx_ni(skb);
+	tun->dev->last_rx = jiffies;
+   
+	tun->stats.rx_packets++;
+	tun->stats.rx_bytes += len;
+
+	return count;
+} 
+
+static inline size_t iov_total(const struct iovec *iv, unsigned long count)
+{
+	unsigned long i;
+	size_t len;
+
+	for (i = 0, len = 0; i < count; i++) 
+		len += iv[i].iov_len;
+
+	return len;
+}
+
+/* Writev */
+static ssize_t tun_chr_writev(struct file * file, const struct iovec *iv, 
+			      unsigned long count, loff_t *pos)
+{
+	struct tun_struct *tun = file->private_data;
+
+	if (!tun)
+		return -EBADFD;
+
+	DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
+
+	return tun_get_user(tun, (struct iovec *) iv, iov_total(iv, count));
+}
+
+/* Write */
+static ssize_t tun_chr_write(struct file * file, const char __user * buf, 
+			     size_t count, loff_t *pos)
+{
+	struct iovec iv = { (void __user *) buf, count };
+	return tun_chr_writev(file, &iv, 1, pos);
+}
+
+/* Put packet to the user space buffer */
+static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
+				       struct sk_buff *skb,
+				       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_toiovec(iv, (void *) &pi, sizeof(pi)))
+			return -EFAULT;
+		total += sizeof(pi);
+	}       
+
+	len = min_t(int, skb->len, len);
+
+	skb_copy_datagram_iovec(skb, 0, iv, len);
+	total += len;
+
+	tun->stats.tx_packets++;
+	tun->stats.tx_bytes += len;
+
+	return total;
+}
+
+/* Readv */
+static ssize_t tun_chr_readv(struct file *file, const struct iovec *iv,
+			    unsigned long count, loff_t *pos)
+{
+	struct tun_struct *tun = file->private_data;
+	DECLARE_WAITQUEUE(wait, current);
+	struct sk_buff *skb;
+	ssize_t len, ret = 0;
+
+	if (!tun)
+		return -EBADFD;
+
+	DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
+
+	len = iov_total(iv, count);
+	if (len < 0)
+		return -EINVAL;
+
+	add_wait_queue(&tun->read_wait, &wait);
+	while (len) {
+		const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
+		u8 addr[ ETH_ALEN];
+		int bit_nr;
+
+		current->state = TASK_INTERRUPTIBLE;
+
+		/* Read frames from the queue */
+		if (!(skb=skb_dequeue(&tun->readq))) {
+			if (file->f_flags & O_NONBLOCK) {
+				ret = -EAGAIN;
+				break;
+			}
+			if (signal_pending(current)) {
+				ret = -ERESTARTSYS;
+				break;
+			}
+
+			/* Nothing to read, let's sleep */
+			schedule();
+			continue;
+		}
+		netif_wake_queue(tun->dev);
+
+		/** Decide whether to accept this packet. This code is designed to
+		 * behave identically to an Ethernet interface. Accept the packet if
+		 * - we are promiscuous.
+		 * - the packet is addressed to us.
+		 * - the packet is broadcast.
+		 * - the packet is multicast and
+		 *   - we are multicast promiscous.
+		 *   - we belong to the multicast group.
+		 */
+		memcpy(addr, skb->data,
+		       min_t(size_t, sizeof addr, skb->len));
+		bit_nr = ether_crc(sizeof addr, addr) >> 26;
+		if ((tun->if_flags & IFF_PROMISC) ||
+				memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
+				memcmp(addr, ones, sizeof addr) == 0 ||
+				(((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
+				  (addr[0] == 0x33 && addr[1] == 0x33)) &&
+				 ((tun->if_flags & IFF_ALLMULTI) ||
+				  (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
+			DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %x:%x:%x:%x:%x:%x\n",
+					tun->dev->name, addr[0], addr[1], addr[2],
+					addr[3], addr[4], addr[5]);
+			ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
+			kfree_skb(skb);
+			break;
+		} else {
+			DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %x:%x:%x:%x:%x:%x\n",
+					tun->dev->name, addr[0], addr[1], addr[2],
+					addr[3], addr[4], addr[5]);
+			kfree_skb(skb);
+			continue;
+		}
+	}
+
+	current->state = TASK_RUNNING;
+	remove_wait_queue(&tun->read_wait, &wait);
+
+	return ret;
+}
+
+/* Read */
+static ssize_t tun_chr_read(struct file * file, char __user * buf, 
+			    size_t count, loff_t *pos)
+{
+	struct iovec iv = { buf, count };
+	return tun_chr_readv(file, &iv, 1, pos);
+}
+
+static void tun_setup(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+
+	skb_queue_head_init(&tun->readq);
+	init_waitqueue_head(&tun->read_wait);
+
+	tun->owner = -1;
+
+	SET_MODULE_OWNER(dev);
+	dev->open = tun_net_open;
+	dev->hard_start_xmit = tun_net_xmit;
+	dev->stop = tun_net_close;
+	dev->get_stats = tun_net_stats;
+	dev->ethtool_ops = &tun_ethtool_ops;
+	dev->destructor = free_netdev;
+}
+
+static struct tun_struct *tun_get_by_name(const char *name)
+{
+	struct tun_struct *tun;
+
+	ASSERT_RTNL();
+	list_for_each_entry(tun, &tun_dev_list, list) {
+		if (!strncmp(tun->dev->name, name, IFNAMSIZ))
+		    return tun;
+	}
+
+	return NULL;
+}
+
+static int tun_set_iff(struct file *file, struct ifreq *ifr)
+{
+	struct tun_struct *tun;
+	struct net_device *dev;
+	int err;
+
+	tun = tun_get_by_name(ifr->ifr_name);
+	if (tun) {
+		if (tun->attached)
+			return -EBUSY;
+
+		/* Check permissions */
+		if (tun->owner != -1 &&
+		    current->euid != tun->owner && !capable(CAP_NET_ADMIN))
+			return -EPERM;
+	} 
+	else if (__dev_get_by_name(ifr->ifr_name)) 
+		return -EINVAL;
+	else {
+		char *name;
+		unsigned long flags = 0;
+
+		err = -EINVAL;
+
+		/* 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 
+			goto failed;
+   
+		if (*ifr->ifr_name)
+			name = ifr->ifr_name;
+
+		dev = alloc_netdev(sizeof(struct tun_struct), name,
+				   tun_setup);
+		if (!dev)
+			return -ENOMEM;
+
+		tun = netdev_priv(dev);
+		tun->dev = dev;
+		tun->flags = flags;
+		/* Be promiscuous by default to maintain previous behaviour. */
+		tun->if_flags = IFF_PROMISC;
+		/* Generate random Ethernet address. */
+		*(u16 *)tun->dev_addr = htons(0x00FF);
+		get_random_bytes(tun->dev_addr + sizeof(u16), 4);
+		memset(tun->chr_filter, 0, sizeof tun->chr_filter);
+
+		tun_net_init(dev);
+
+		if (strchr(dev->name, '%')) {
+			err = dev_alloc_name(dev, dev->name);
+			if (err < 0)
+				goto err_free_dev;
+		}
+
+		err = register_netdevice(tun->dev);
+		if (err < 0)
+			goto err_free_dev;
+	
+		list_add(&tun->list, &tun_dev_list);
+	}
+
+	DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
+
+	if (ifr->ifr_flags & IFF_NO_PI)
+		tun->flags |= TUN_NO_PI;
+
+	if (ifr->ifr_flags & IFF_ONE_QUEUE)
+		tun->flags |= TUN_ONE_QUEUE;
+
+	file->private_data = tun;
+	tun->attached = 1;
+
+	strcpy(ifr->ifr_name, tun->dev->name);
+	return 0;
+
+ err_free_dev:
+	free_netdev(dev);
+ failed:
+	return err;
+}
+
+static int tun_chr_ioctl(struct inode *inode, struct file *file, 
+			 unsigned int cmd, unsigned long arg)
+{
+	struct tun_struct *tun = file->private_data;
+	void __user* argp = (void __user*)arg;
+	struct ifreq ifr;
+
+	if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
+		if (copy_from_user(&ifr, argp, sizeof ifr))
+			return -EFAULT;
+
+	if (cmd == TUNSETIFF && !tun) {
+		int err;
+
+		ifr.ifr_name[IFNAMSIZ-1] = '\0';
+
+		rtnl_lock();
+		err = tun_set_iff(file, &ifr);
+		rtnl_unlock();
+
+		if (err)
+			return err;
+
+		if (copy_to_user(argp, &ifr, sizeof(ifr)))
+			return -EFAULT;
+		return 0;
+	}
+
+	if (!tun)
+		return -EBADFD;
+
+	DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
+
+	switch (cmd) {
+	case TUNSETNOCSUM:
+		/* Disable/Enable checksum */
+		if (arg)
+			tun->flags |= TUN_NOCHECKSUM;
+		else
+			tun->flags &= ~TUN_NOCHECKSUM;
+
+		DBG(KERN_INFO "%s: checksum %s\n",
+		    tun->dev->name, arg ? "disabled" : "enabled");
+		break;
+
+	case TUNSETPERSIST:
+		/* Disable/Enable persist mode */
+		if (arg)
+			tun->flags |= TUN_PERSIST;
+		else
+			tun->flags &= ~TUN_PERSIST;
+
+		DBG(KERN_INFO "%s: persist %s\n",
+		    tun->dev->name, arg ? "disabled" : "enabled");
+		break;
+
+	case TUNSETOWNER:
+		/* Set owner of the device */
+		tun->owner = (uid_t) arg;
+
+		DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
+		break;
+
+#ifdef TUN_DEBUG
+	case TUNSETDEBUG:
+		tun->debug = arg;
+		break;
+#endif
+
+	case SIOCGIFFLAGS:
+		ifr.ifr_flags = tun->if_flags;
+		if (copy_to_user( argp, &ifr, sizeof ifr))
+			return -EFAULT;
+		return 0;
+
+	case SIOCSIFFLAGS:
+		/** Set the character device's interface flags. Currently only
+		 * IFF_PROMISC and IFF_ALLMULTI are used. */
+		tun->if_flags = ifr.ifr_flags;
+		DBG(KERN_INFO "%s: interface flags 0x%lx\n",
+				tun->dev->name, tun->if_flags);
+		return 0;
+
+	case SIOCGIFHWADDR:
+		memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
+				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
+		if (copy_to_user( argp, &ifr, sizeof ifr))
+			return -EFAULT;
+		return 0;
+
+	case SIOCSIFHWADDR:
+		/** Set the character device's hardware address. This is used when
+		 * filtering packets being sent from the network device to the character
+		 * device. */
+		memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
+				min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
+		DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
+				tun->dev->name,
+				tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
+				tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
+		return 0;
+
+	case SIOCADDMULTI:
+		/** Add the specified group to the character device's multicast filter
+		 * list. */
+		add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
+		DBG(KERN_DEBUG "%s: add multi: %x:%x:%x:%x:%x:%x\n",
+				tun->dev->name,
+				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
+				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
+				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
+		return 0;
+
+	case SIOCDELMULTI:
+		/** Remove the specified group from the character device's multicast
+		 * filter list. */
+		del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
+		DBG(KERN_DEBUG "%s: del multi: %x:%x:%x:%x:%x:%x\n",
+				tun->dev->name,
+				(u8)ifr.ifr_hwaddr.sa_data[0], (u8)ifr.ifr_hwaddr.sa_data[1],
+				(u8)ifr.ifr_hwaddr.sa_data[2], (u8)ifr.ifr_hwaddr.sa_data[3],
+				(u8)ifr.ifr_hwaddr.sa_data[4], (u8)ifr.ifr_hwaddr.sa_data[5]);
+		return 0;
+
+	default:
+		return -EINVAL;
+	};
+
+	return 0;
+}
+
+static int tun_chr_fasync(int fd, struct file *file, int on)
+{
+	struct tun_struct *tun = file->private_data;
+	int ret;
+
+	if (!tun)
+		return -EBADFD;
+
+	DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
+
+	if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
+		return ret; 
+ 
+	if (on) {
+		ret = f_setown(file, current->pid, 0);
+		if (ret)
+			return ret;
+		tun->flags |= TUN_FASYNC;
+	} else 
+		tun->flags &= ~TUN_FASYNC;
+
+	return 0;
+}
+
+static int tun_chr_open(struct inode *inode, struct file * file)
+{
+	DBG1(KERN_INFO "tunX: tun_chr_open\n");
+	file->private_data = NULL;
+	return 0;
+}
+
+static int tun_chr_close(struct inode *inode, struct file *file)
+{
+	struct tun_struct *tun = file->private_data;
+
+	if (!tun)
+		return 0;
+
+	DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
+
+	tun_chr_fasync(-1, file, 0);
+
+	rtnl_lock();
+
+	/* Detach from net device */
+	file->private_data = NULL;
+	tun->attached = 0;
+
+	/* Drop read queue */
+	skb_queue_purge(&tun->readq);
+
+	if (!(tun->flags & TUN_PERSIST)) {
+		list_del(&tun->list);
+		unregister_netdevice(tun->dev);
+	}
+
+	rtnl_unlock();
+
+	return 0;
+}
+
+static struct file_operations tun_fops = {
+	.owner	= THIS_MODULE,	
+	.llseek = no_llseek,
+	.read	= tun_chr_read,
+	.readv	= tun_chr_readv,
+	.write	= tun_chr_write,
+	.writev = tun_chr_writev,
+	.poll	= tun_chr_poll,
+	.ioctl	= tun_chr_ioctl,
+	.open	= tun_chr_open,
+	.release = tun_chr_close,
+	.fasync = tun_chr_fasync		
+};
+
+static struct miscdevice tun_miscdev = {
+	.minor = TUN_MINOR,
+	.name = "tun",
+	.fops = &tun_fops,
+	.devfs_name = "net/tun",
+};
+
+/* ethtool interface */
+
+static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
+{
+	cmd->supported		= 0;
+	cmd->advertising	= 0;
+	cmd->speed		= 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);
+
+	strcpy(info->driver, DRV_NAME);
+	strcpy(info->version, DRV_VERSION);
+	strcpy(info->fw_version, "N/A");
+
+	switch (tun->flags & TUN_TYPE_MASK) {
+	case TUN_TUN_DEV:
+		strcpy(info->bus_info, "tun");
+		break;
+	case TUN_TAP_DEV:
+		strcpy(info->bus_info, "tap");
+		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 u32 tun_get_link(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	return tun->attached;
+}
+
+static u32 tun_get_rx_csum(struct net_device *dev)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	return (tun->flags & TUN_NOCHECKSUM) == 0;
+}
+
+static int tun_set_rx_csum(struct net_device *dev, u32 data)
+{
+	struct tun_struct *tun = netdev_priv(dev);
+	if (data)
+		tun->flags &= ~TUN_NOCHECKSUM;
+	else
+		tun->flags |= TUN_NOCHECKSUM;
+	return 0;
+}
+
+static 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	= tun_get_link,
+	.get_rx_csum	= tun_get_rx_csum,
+	.set_rx_csum	= tun_set_rx_csum
+};
+
+static int __init tun_init(void)
+{
+	int ret = 0;
+
+	printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
+	printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
+
+	ret = misc_register(&tun_miscdev);
+	if (ret)
+		printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
+	return ret;
+}
+
+static void tun_cleanup(void)
+{
+	struct tun_struct *tun, *nxt;
+
+	misc_deregister(&tun_miscdev);  
+
+	rtnl_lock();
+	list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
+		DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
+		unregister_netdevice(tun->dev);
+	}
+	rtnl_unlock();
+	
+}
+
+module_init(tun_init);
+module_exit(tun_cleanup);
+MODULE_DESCRIPTION(DRV_DESCRIPTION);
+MODULE_AUTHOR(DRV_COPYRIGHT);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(TUN_MINOR);