Driver-Core: extend devnode callbacks to provide permissions
[safe/jmp/linux-2.6] / drivers / net / tun.c
index a314955..d3ee199 100644 (file)
 /*
  *  Changes:
  *
- *  Brian Braunstein <linuxkernel@bristyle.com> 2007/03/23
- *    Fixed hw address handling.  Now net_device.dev_addr is kept consistent
- *    with tun.dev_addr when the address is set by this module.
- *
  *  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.
+ *    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.
@@ -48,6 +44,7 @@
 #include <linux/kernel.h>
 #include <linux/major.h>
 #include <linux/slab.h>
+#include <linux/smp_lock.h>
 #include <linux/poll.h>
 #include <linux/fcntl.h>
 #include <linux/init.h>
 #include <linux/if_tun.h>
 #include <linux/crc32.h>
 #include <linux/nsproxy.h>
+#include <linux/virtio_net.h>
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -82,39 +82,257 @@ static int debug;
 #define DBG1( a... )
 #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 list_head        list;
-       unsigned long           flags;
-       int                     attached;
+       struct tun_file         *tfile;
+       unsigned int            flags;
        uid_t                   owner;
        gid_t                   group;
 
-       wait_queue_head_t       read_wait;
-       struct sk_buff_head     readq;
-
        struct net_device       *dev;
+       struct fasync_struct    *fasync;
 
-       struct fasync_struct    *fasync;
-
-       unsigned long if_flags;
-       u8 dev_addr[ETH_ALEN];
-       u32 chr_filter[2];
-       u32 net_filter[2];
+       struct tap_filter       txflt;
+       struct socket           socket;
 
 #ifdef TUN_DEBUG
        int debug;
 #endif
 };
 
-/* Network device part of the driver */
-
-static unsigned int tun_net_id;
-struct tun_net {
-       struct list_head dev_list;
+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;
+       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);
+       tun->tfile = 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 filterting */
+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->socket.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);
+
+       sock_put(tun->socket.sk);
+}
+
 /* Net device open. */
 static int tun_net_open(struct net_device *dev)
 {
@@ -130,18 +348,23 @@ static int tun_net_close(struct net_device *dev)
 }
 
 /* Net device start xmit */
-static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
+static netdev_tx_t 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)
+       if (!tun->tfile)
                goto drop;
 
-       /* Packet dropping */
-       if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
+       /* 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 (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. */
@@ -157,57 +380,30 @@ static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
                }
        }
 
-       /* Queue packet */
-       skb_queue_tail(&tun->readq, skb);
+       /* Enqueue packet */
+       skb_queue_tail(&tun->socket.sk->sk_receive_queue, 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;
+       wake_up_interruptible(&tun->socket.wait);
+       return NETDEV_TX_OK;
 
 drop:
        dev->stats.tx_dropped++;
        kfree_skb(skb);
-       return 0;
+       return NETDEV_TX_OK;
 }
 
-/** Add the specified Ethernet address to this multicast filter. */
-static void
-add_multi(u32* filter, const u8* addr)
+static void tun_net_mclist(struct net_device *dev)
 {
-       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;
-       DECLARE_MAC_BUF(mac);
-       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: %s\n",
-                   dev->name, print_mac(mac, mclist->dmi_addr));
-       }
+       /*
+        * 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.
+        */
+       return;
 }
 
 #define MIN_MTU 68
@@ -222,6 +418,25 @@ tun_net_change_mtu(struct net_device *dev, int new_mtu)
        return 0;
 }
 
+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,
+};
+
+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_set_multicast_list = tun_net_mclist,
+       .ndo_set_mac_address    = eth_mac_addr,
+       .ndo_validate_addr      = eth_validate_addr,
+};
+
 /* Initialize net device. */
 static void tun_net_init(struct net_device *dev)
 {
@@ -229,11 +444,12 @@ static void tun_net_init(struct net_device *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;
-               dev->change_mtu = tun_net_change_mtu;
 
                /* Zero header length */
                dev->type = ARPHRD_NONE;
@@ -242,14 +458,11 @@ static void tun_net_init(struct net_device *dev)
                break;
 
        case TUN_TAP_DEV:
+               dev->netdev_ops = &tap_netdev_ops;
                /* Ethernet TAP Device */
-               dev->set_multicast_list = tun_net_mclist;
-
                ether_setup(dev);
-               dev->change_mtu = tun_net_change_mtu;
 
-               /* random address already created for us by tun_set_iff, use it */
-               memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) );
+               random_ether_addr(dev->dev_addr);
 
                dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
                break;
@@ -261,56 +474,128 @@ static void tun_net_init(struct net_device *dev)
 /* 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;
+       struct tun_file *tfile = file->private_data;
+       struct tun_struct *tun = __tun_get(tfile);
+       struct sock *sk;
+       unsigned int mask = 0;
 
        if (!tun)
-               return -EBADFD;
+               return POLLERR;
+
+       sk = tun->socket.sk;
 
        DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 
-       poll_wait(file, &tun->read_wait, wait);
+       poll_wait(file, &tun->socket.wait, wait);
 
-       if (!skb_queue_empty(&tun->readq))
+       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 inline 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;
+
+       /* 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 __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
+static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
+                                      const struct iovec *iv, size_t count,
+                                      int noblock)
 {
-       struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
+       struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
        struct sk_buff *skb;
        size_t len = count, align = 0;
+       struct virtio_net_hdr gso = { 0 };
+       int offset = 0;
 
        if (!(tun->flags & TUN_NO_PI)) {
                if ((len -= sizeof(pi)) > count)
                        return -EINVAL;
 
-               if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
+               if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
                        return -EFAULT;
+               offset += sizeof(pi);
+       }
+
+       if (tun->flags & TUN_VNET_HDR) {
+               if ((len -= sizeof(gso)) > 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 += sizeof(gso);
        }
 
        if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
                align = NET_IP_ALIGN;
-               if (unlikely(len < ETH_HLEN))
+               if (unlikely(len < ETH_HLEN ||
+                            (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
                        return -EINVAL;
        }
 
-       if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
-               tun->dev->stats.rx_dropped++;
-               return -ENOMEM;
+       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 (align)
-               skb_reserve(skb, align);
-       if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
+       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;
+               }
+       } else if (tun->flags & TUN_NOCHECKSUM)
+               skb->ip_summed = CHECKSUM_UNNECESSARY;
+
        switch (tun->flags & TUN_TYPE_MASK) {
        case TUN_TUN_DEV:
                if (tun->flags & TUN_NO_PI) {
@@ -337,11 +622,40 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
                break;
        };
 
-       if (tun->flags & TUN_NOCHECKSUM)
-               skb->ip_summed = CHECKSUM_UNNECESSARY;
+       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->last_rx = jiffies;
 
        tun->dev->stats.rx_packets++;
        tun->dev->stats.rx_bytes += len;
@@ -352,20 +666,26 @@ static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv,
 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
                              unsigned long count, loff_t pos)
 {
-       struct tun_struct *tun = iocb->ki_filp->private_data;
+       struct file *file = iocb->ki_filp;
+       struct tun_struct *tun = tun_get(file);
+       ssize_t result;
 
        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_length(iv, 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 __inline__ ssize_t tun_put_user(struct tun_struct *tun,
                                       struct sk_buff *skb,
-                                      struct iovec *iv, int len)
+                                      const struct iovec *iv, int len)
 {
        struct tun_pi pi = { 0, skb->protocol };
        ssize_t total = 0;
@@ -379,14 +699,50 @@ static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
                        pi.flags |= TUN_PKT_STRIP;
                }
 
-               if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
+               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 -= sizeof(gso)) < 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
+                               BUG();
+                       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->csum_start - skb_headroom(skb);
+                       gso.csum_offset = skb->csum_offset;
+               } /* else everything is zero */
+
+               if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
+                                              sizeof(gso))))
+                       return -EFAULT;
+               total += sizeof(gso);
+       }
+
        len = min_t(int, skb->len, len);
 
-       skb_copy_datagram_iovec(skb, 0, iv, len);
+       skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
        total += len;
 
        tun->dev->stats.tx_packets++;
@@ -399,11 +755,11 @@ 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_struct *tun = file->private_data;
+       struct tun_file *tfile = file->private_data;
+       struct tun_struct *tun = __tun_get(tfile);
        DECLARE_WAITQUEUE(wait, current);
        struct sk_buff *skb;
        ssize_t len, ret = 0;
-       DECLARE_MAC_BUF(mac);
 
        if (!tun)
                return -EBADFD;
@@ -411,19 +767,17 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
        DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 
        len = iov_length(iv, count);
-       if (len < 0)
-               return -EINVAL;
+       if (len < 0) {
+               ret = -EINVAL;
+               goto out;
+       }
 
-       add_wait_queue(&tun->read_wait, &wait);
+       add_wait_queue(&tun->socket.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 (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
                        if (file->f_flags & O_NONBLOCK) {
                                ret = -EAGAIN;
                                break;
@@ -432,6 +786,10 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                                ret = -ERESTARTSYS;
                                break;
                        }
+                       if (tun->dev->reg_state != NETREG_REGISTERED) {
+                               ret = -EIO;
+                               break;
+                       }
 
                        /* Nothing to read, let's sleep */
                        schedule();
@@ -439,41 +797,16 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
                }
                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.
-                */
-               skb_copy_from_linear_data(skb, addr, 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: %s\n",
-                                       tun->dev->name, print_mac(mac, addr));
-                       ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
-                       kfree_skb(skb);
-                       break;
-               } else {
-                       DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n",
-                                       tun->dev->name, print_mac(mac, addr));
-                       kfree_skb(skb);
-                       continue;
-               }
+               ret = tun_put_user(tun, skb, iv, len);
+               kfree_skb(skb);
+               break;
        }
 
        current->state = TASK_RUNNING;
-       remove_wait_queue(&tun->read_wait, &wait);
+       remove_wait_queue(&tun->socket.wait, &wait);
 
+out:
+       tun_put(tun);
        return ret;
 }
 
@@ -481,56 +814,134 @@ 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;
        tun->group = -1;
 
-       dev->open = tun_net_open;
-       dev->hard_start_xmit = tun_net_xmit;
-       dev->stop = tun_net_close;
        dev->ethtool_ops = &tun_ethtool_ops;
-       dev->destructor = free_netdev;
-       dev->features |= NETIF_F_NETNS_LOCAL;
+       dev->destructor = tun_free_netdev;
 }
 
-static struct tun_struct *tun_get_by_name(struct tun_net *tn, const char *name)
+/* 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;
 
-       ASSERT_RTNL();
-       list_for_each_entry(tun, &tn->dev_list, list) {
-               if (!strncmp(tun->dev->name, name, IFNAMSIZ))
-                   return tun;
-       }
+       if (!sock_writeable(sk))
+               return;
+
+       if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+               return;
+
+       if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+               wake_up_interruptible_sync(sk->sk_sleep);
 
-       return NULL;
+       tun = container_of(sk, struct tun_sock, sk)->tun;
+       kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 }
 
+static void tun_sock_destruct(struct sock *sk)
+{
+       free_netdev(container_of(sk, struct tun_sock, sk)->tun->dev);
+}
+
+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 tun_net *tn;
+       struct sock *sk;
        struct tun_struct *tun;
        struct net_device *dev;
        int err;
 
-       tn = net_generic(net, tun_net_id);
-       tun = tun_get_by_name(tn, ifr->ifr_name);
-       if (tun) {
-               if (tun->attached)
+       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;
 
-               /* Check permissions */
-               if (((tun->owner != -1 &&
-                     current->euid != tun->owner) ||
-                    (tun->group != -1 &&
-                     current->egid != tun->group)) &&
-                    !capable(CAP_NET_ADMIN))
+               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 if (__dev_get_by_name(net, ifr->ifr_name))
-               return -EINVAL;
        else {
                char *name;
                unsigned long flags = 0;
@@ -539,6 +950,9 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 
                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) {
@@ -561,29 +975,49 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
                        return -ENOMEM;
 
                dev_net_set(dev, net);
+               dev->rtnl_link_ops = &tun_link_ops;
+
                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. */
-               *(__be16 *)tun->dev_addr = htons(0x00FF);
-               get_random_bytes(tun->dev_addr + sizeof(u16), 4);
-               memset(tun->chr_filter, 0, sizeof tun->chr_filter);
+               tun->txflt.count = 0;
+
+               err = -ENOMEM;
+               sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
+               if (!sk)
+                       goto err_free_dev;
+
+               init_waitqueue_head(&tun->socket.wait);
+               sock_init_data(&tun->socket, sk);
+               sk->sk_write_space = tun_sock_write_space;
+               sk->sk_sndbuf = INT_MAX;
+
+               container_of(sk, struct tun_sock, sk)->tun = tun;
+
+               security_tun_dev_post_create(sk);
 
                tun_net_init(dev);
 
                if (strchr(dev->name, '%')) {
                        err = dev_alloc_name(dev, dev->name);
                        if (err < 0)
-                               goto err_free_dev;
+                               goto err_free_sk;
                }
 
                err = register_netdevice(tun->dev);
                if (err < 0)
-                       goto err_free_dev;
+                       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))
+                       printk(KERN_ERR "Failed to create tun sysfs files\n");
 
-               list_add(&tun->list, &tn->dev_list);
+               sk->sk_destruct = tun_sock_destruct;
+
+               err = tun_attach(tun, file);
+               if (err < 0)
+                       goto failed;
        }
 
        DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
@@ -598,19 +1032,40 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
        else
                tun->flags &= ~TUN_ONE_QUEUE;
 
-       file->private_data = tun;
-       tun->attached = 1;
-       get_net(dev_net(tun->dev));
+       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:
+       sock_put(sk);
  err_free_dev:
        free_netdev(dev);
  failed:
        return err;
 }
 
+static int tun_get_iff(struct net *net, struct tun_struct *tun,
+                      struct ifreq *ifr)
+{
+       DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
+
+       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 net_device *dev, unsigned long arg)
@@ -620,7 +1075,8 @@ static int set_offload(struct net_device *dev, unsigned long arg)
        old_features = dev->features;
        /* Unset features, set them as we chew on the arg. */
        features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
-                                   |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
+                                   |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6
+                                   |NETIF_F_UFO));
 
        if (arg & TUN_F_CSUM) {
                features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
@@ -637,6 +1093,11 @@ static int set_offload(struct net_device *dev, unsigned long arg)
                                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
@@ -651,49 +1112,62 @@ static int set_offload(struct net_device *dev, unsigned long arg)
        return 0;
 }
 
-static int tun_chr_ioctl(struct inode *inode, struct file *file,
-                        unsigned int cmd, unsigned long arg)
+static long tun_chr_ioctl(struct file *file, unsigned int cmd,
+                         unsigned long arg)
 {
-       struct tun_struct *tun = file->private_data;
+       struct tun_file *tfile = file->private_data;
+       struct tun_struct *tun;
        void __user* argp = (void __user*)arg;
        struct ifreq ifr;
-       DECLARE_MAC_BUF(mac);
+       int sndbuf;
+       int ret;
 
        if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
                if (copy_from_user(&ifr, argp, sizeof ifr))
                        return -EFAULT;
 
-       if (cmd == TUNSETIFF && !tun) {
-               int err;
+       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';
 
-               rtnl_lock();
-               err = tun_set_iff(current->nsproxy->net_ns, file, &ifr);
-               rtnl_unlock();
+               ret = tun_set_iff(tfile->net, file, &ifr);
 
-               if (err)
-                       return err;
+               if (ret)
+                       goto unlock;
 
                if (copy_to_user(argp, &ifr, sizeof(ifr)))
-                       return -EFAULT;
-               return 0;
-       }
-
-       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,
-                               (unsigned int __user*)argp);
+                       ret = -EFAULT;
+               goto unlock;
        }
 
+       ret = -EBADFD;
        if (!tun)
-               return -EBADFD;
+               goto unlock;
 
        DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, 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, sizeof(ifr)))
+                       ret = -EFAULT;
+               break;
+
        case TUNSETNOCSUM:
                /* Disable/Enable checksum */
                if (arg)
@@ -731,11 +1205,7 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                break;
 
        case TUNSETLINK:
-       {
-               int ret;
-
                /* Only allow setting the type when the interface is down */
-               rtnl_lock();
                if (tun->dev->flags & IFF_UP) {
                        DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
                                tun->dev->name);
@@ -745,107 +1215,71 @@ static int tun_chr_ioctl(struct inode *inode, struct file *file,
                        DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
                        ret = 0;
                }
-               rtnl_unlock();
-               return ret;
-       }
+               break;
 
 #ifdef TUN_DEBUG
        case TUNSETDEBUG:
                tun->debug = arg;
                break;
 #endif
-
        case TUNSETOFFLOAD:
-       {
-               int ret;
-               rtnl_lock();
                ret = set_offload(tun->dev, arg);
-               rtnl_unlock();
-               return ret;
-       }
-
-       case SIOCGIFFLAGS:
-               ifr.ifr_flags = tun->if_flags;
-               if (copy_to_user( argp, &ifr, sizeof ifr))
-                       return -EFAULT;
-               return 0;
+               break;
 
-       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 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:
-               /* Note: the actual net device's address may be different */
-               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;
+               /* Get hw addres */
+               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, sizeof ifr))
+                       ret = -EFAULT;
+               break;
 
        case SIOCSIFHWADDR:
-       {
-               /* try to set the actual net device's hw address */
-               int ret;
+               /* Set hw address */
+               DBG(KERN_DEBUG "%s: set hw address: %pM\n",
+                       tun->dev->name, ifr.ifr_hwaddr.sa_data);
 
-               rtnl_lock();
                ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
-               rtnl_unlock();
-
-               if (ret == 0) {
-                       /** 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]);
-               }
+               break;
 
-               return  ret;
-       }
+       case TUNGETSNDBUF:
+               sndbuf = tun->socket.sk->sk_sndbuf;
+               if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
+                       ret = -EFAULT;
+               break;
 
-       case SIOCADDMULTI:
-               /** Add the specified group to the character device's multicast filter
-                * list. */
-               rtnl_lock();
-               netif_tx_lock_bh(tun->dev);
-               add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
-               netif_tx_unlock_bh(tun->dev);
-               rtnl_unlock();
-
-               DBG(KERN_DEBUG "%s: add multi: %s\n",
-                   tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
-               return 0;
+       case TUNSETSNDBUF:
+               if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
+                       ret = -EFAULT;
+                       break;
+               }
 
-       case SIOCDELMULTI:
-               /** Remove the specified group from the character device's multicast
-                * filter list. */
-               rtnl_lock();
-               netif_tx_lock_bh(tun->dev);
-               del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
-               netif_tx_unlock_bh(tun->dev);
-               rtnl_unlock();
-
-               DBG(KERN_DEBUG "%s: del multi: %s\n",
-                   tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
-               return 0;
+               tun->socket.sk->sk_sndbuf = sndbuf;
+               break;
 
        default:
-               return -EINVAL;
+               ret = -EINVAL;
+               break;
        };
 
-       return 0;
+unlock:
+       rtnl_unlock();
+       if (tun)
+               tun_put(tun);
+       return ret;
 }
 
 static int tun_chr_fasync(int fd, struct file *file, int on)
 {
-       struct tun_struct *tun = file->private_data;
+       struct tun_struct *tun = tun_get(file);
        int ret;
 
        if (!tun)
@@ -853,54 +1287,68 @@ static int tun_chr_fasync(int fd, struct file *file, int on)
 
        DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 
+       lock_kernel();
        if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
-               return ret;
+               goto out;
 
        if (on) {
                ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
                if (ret)
-                       return ret;
+                       goto out;
                tun->flags |= TUN_FASYNC;
        } else
                tun->flags &= ~TUN_FASYNC;
-
-       return 0;
+       ret = 0;
+out:
+       unlock_kernel();
+       tun_put(tun);
+       return ret;
 }
 
 static int tun_chr_open(struct inode *inode, struct file * file)
 {
+       struct tun_file *tfile;
+       cycle_kernel_lock();
        DBG1(KERN_INFO "tunX: tun_chr_open\n");
-       file->private_data = NULL;
+
+       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_struct *tun = file->private_data;
-
-       if (!tun)
-               return 0;
-
-       DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
+       struct tun_file *tfile = file->private_data;
+       struct tun_struct *tun;
 
-       tun_chr_fasync(-1, file, 0);
+       tun = __tun_get(tfile);
+       if (tun) {
+               struct net_device *dev = tun->dev;
 
-       rtnl_lock();
+               DBG(KERN_INFO "%s: tun_chr_close\n", dev->name);
 
-       /* Detach from net device */
-       file->private_data = NULL;
-       tun->attached = 0;
-       put_net(dev_net(tun->dev));
+               __tun_detach(tun);
 
-       /* Drop read queue */
-       skb_queue_purge(&tun->readq);
-
-       if (!(tun->flags & TUN_PERSIST)) {
-               list_del(&tun->list);
-               unregister_netdevice(tun->dev);
+               /* If desireable, unregister the netdevice. */
+               if (!(tun->flags & TUN_PERSIST)) {
+                       rtnl_lock();
+                       if (dev->reg_state == NETREG_REGISTERED)
+                               unregister_netdevice(dev);
+                       rtnl_unlock();
+               }
        }
 
-       rtnl_unlock();
+       tun = tfile->tun;
+       if (tun)
+               sock_put(tun->socket.sk);
+
+       put_net(tfile->net);
+       kfree(tfile);
 
        return 0;
 }
@@ -913,7 +1361,7 @@ static const struct file_operations tun_fops = {
        .write = do_sync_write,
        .aio_write = tun_chr_aio_write,
        .poll   = tun_chr_poll,
-       .ioctl  = tun_chr_ioctl,
+       .unlocked_ioctl = tun_chr_ioctl,
        .open   = tun_chr_open,
        .release = tun_chr_close,
        .fasync = tun_chr_fasync
@@ -922,6 +1370,7 @@ static const struct file_operations tun_fops = {
 static struct miscdevice tun_miscdev = {
        .minor = TUN_MINOR,
        .name = "tun",
+       .nodename = "net/tun",
        .fops = &tun_fops,
 };
 
@@ -981,7 +1430,7 @@ static void tun_set_msglevel(struct net_device *dev, u32 value)
 static u32 tun_get_link(struct net_device *dev)
 {
        struct tun_struct *tun = netdev_priv(dev);
-       return tun->attached;
+       return !!tun->tfile;
 }
 
 static u32 tun_get_rx_csum(struct net_device *dev)
@@ -1010,45 +1459,6 @@ static const struct ethtool_ops tun_ethtool_ops = {
        .set_rx_csum    = tun_set_rx_csum
 };
 
-static int tun_init_net(struct net *net)
-{
-       struct tun_net *tn;
-
-       tn = kmalloc(sizeof(*tn), GFP_KERNEL);
-       if (tn == NULL)
-               return -ENOMEM;
-
-       INIT_LIST_HEAD(&tn->dev_list);
-
-       if (net_assign_generic(net, tun_net_id, tn)) {
-               kfree(tn);
-               return -ENOMEM;
-       }
-
-       return 0;
-}
-
-static void tun_exit_net(struct net *net)
-{
-       struct tun_net *tn;
-       struct tun_struct *tun, *nxt;
-
-       tn = net_generic(net, tun_net_id);
-
-       rtnl_lock();
-       list_for_each_entry_safe(tun, nxt, &tn->dev_list, list) {
-               DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
-               unregister_netdevice(tun->dev);
-       }
-       rtnl_unlock();
-
-       kfree(tn);
-}
-
-static struct pernet_operations tun_net_ops = {
-       .init = tun_init_net,
-       .exit = tun_exit_net,
-};
 
 static int __init tun_init(void)
 {
@@ -1057,10 +1467,10 @@ static int __init tun_init(void)
        printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
        printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
 
-       ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
+       ret = rtnl_link_register(&tun_link_ops);
        if (ret) {
-               printk(KERN_ERR "tun: Can't register pernet ops\n");
-               goto err_pernet;
+               printk(KERN_ERR "tun: Can't register link_ops\n");
+               goto err_linkops;
        }
 
        ret = misc_register(&tun_miscdev);
@@ -1068,18 +1478,17 @@ static int __init tun_init(void)
                printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
                goto err_misc;
        }
-       return 0;
-
+       return  0;
 err_misc:
-       unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
-err_pernet:
+       rtnl_link_unregister(&tun_link_ops);
+err_linkops:
        return ret;
 }
 
 static void tun_cleanup(void)
 {
        misc_deregister(&tun_miscdev);
-       unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
+       rtnl_link_unregister(&tun_link_ops);
 }
 
 module_init(tun_init);