Merge branch 'wip-2.6.34' into old-private-masterarchived-private-master

1 files changed, 804 insertions, 0 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
new file mode 100644
index 000000000000..abba3cc81f12
--- /dev/null
+++ b/drivers/net/macvtap.c
@@ -0,0 +1,804 @@
+#include <linux/etherdevice.h>
+#include <linux/if_macvlan.h>
+#include <linux/interrupt.h>
+#include <linux/nsproxy.h>
+#include <linux/compat.h>
+#include <linux/if_tun.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/wait.h>
+#include <linux/cdev.h>
+#include <linux/fs.h>
+
+#include <net/net_namespace.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+#include <linux/virtio_net.h>
+
+/*
+ * A macvtap queue is the central object of this driver, it connects
+ * an open character device to a macvlan interface. There can be
+ * multiple queues on one interface, which map back to queues
+ * implemented in hardware on the underlying device.
+ *
+ * macvtap_proto is used to allocate queues through the sock allocation
+ * mechanism.
+ *
+ * TODO: multiqueue support is currently not implemented, even though
+ * macvtap is basically prepared for that. We will need to add this
+ * here as well as in virtio-net and qemu to get line rate on 10gbit
+ * adapters from a guest.
+ */
+struct macvtap_queue {
+        struct sock sk;
+        struct socket sock;
+        struct macvlan_dev *vlan;
+        struct file *file;
+        unsigned int flags;
+};
+
+static struct proto macvtap_proto = {
+        .name = "macvtap",
+        .owner = THIS_MODULE,
+        .obj_size = sizeof (struct macvtap_queue),
+};
+
+/*
+ * Minor number matches netdev->ifindex, so need a potentially
+ * large value. This also makes it possible to split the
+ * tap functionality out again in the future by offering it
+ * from other drivers besides macvtap. As long as every device
+ * only has one tap, the interface numbers assure that the
+ * device nodes are unique.
+ */
+static unsigned int macvtap_major;
+#define MACVTAP_NUM_DEVS 65536
+static struct class *macvtap_class;
+static struct cdev macvtap_cdev;
+
+static const struct proto_ops macvtap_socket_ops;
+
+/*
+ * RCU usage:
+ * The macvtap_queue and the macvlan_dev are loosely coupled, the
+ * pointers from one to the other can only be read while rcu_read_lock
+ * or macvtap_lock is held.
+ *
+ * Both the file and the macvlan_dev hold a reference on the macvtap_queue
+ * through sock_hold(&q->sk). When the macvlan_dev goes away first,
+ * q->vlan becomes inaccessible. When the files gets closed,
+ * macvtap_get_queue() fails.
+ *
+ * There may still be references to the struct sock inside of the
+ * queue from outbound SKBs, but these never reference back to the
+ * file or the dev. The data structure is freed through __sk_free
+ * when both our references and any pending SKBs are gone.
+ */
+static DEFINE_SPINLOCK(macvtap_lock);
+
+/*
+ * Choose the next free queue, for now there is only one
+ */
+static int macvtap_set_queue(struct net_device *dev, struct file *file,
+                                struct macvtap_queue *q)
+{
+        struct macvlan_dev *vlan = netdev_priv(dev);
+        int err = -EBUSY;
+
+        spin_lock(&macvtap_lock);
+        if (rcu_dereference(vlan->tap))
+                goto out;
+
+        err = 0;
+        rcu_assign_pointer(q->vlan, vlan);
+        rcu_assign_pointer(vlan->tap, q);
+        sock_hold(&q->sk);
+
+        q->file = file;
+        file->private_data = q;
+
+out:
+        spin_unlock(&macvtap_lock);
+        return err;
+}
+
+/*
+ * The file owning the queue got closed, give up both
+ * the reference that the files holds as well as the
+ * one from the macvlan_dev if that still exists.
+ *
+ * Using the spinlock makes sure that we don't get
+ * to the queue again after destroying it.
+ */
+static void macvtap_put_queue(struct macvtap_queue *q)
+{
+        struct macvlan_dev *vlan;
+
+        spin_lock(&macvtap_lock);
+        vlan = rcu_dereference(q->vlan);
+        if (vlan) {
+                rcu_assign_pointer(vlan->tap, NULL);
+                rcu_assign_pointer(q->vlan, NULL);
+                sock_put(&q->sk);
+        }
+
+        spin_unlock(&macvtap_lock);
+
+        synchronize_rcu();
+        sock_put(&q->sk);
+}
+
+/*
+ * Since we only support one queue, just dereference the pointer.
+ */
+static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
+                                               struct sk_buff *skb)
+{
+        struct macvlan_dev *vlan = netdev_priv(dev);
+
+        return rcu_dereference(vlan->tap);
+}
+
+/*
+ * The net_device is going away, give up the reference
+ * that it holds on the queue (all the queues one day)
+ * and safely set the pointer from the queues to NULL.
+ */
+static void macvtap_del_queues(struct net_device *dev)
+{
+        struct macvlan_dev *vlan = netdev_priv(dev);
+        struct macvtap_queue *q;
+
+        spin_lock(&macvtap_lock);
+        q = rcu_dereference(vlan->tap);
+        if (!q) {
+                spin_unlock(&macvtap_lock);
+                return;
+        }
+
+        rcu_assign_pointer(vlan->tap, NULL);
+        rcu_assign_pointer(q->vlan, NULL);
+        spin_unlock(&macvtap_lock);
+
+        synchronize_rcu();
+        sock_put(&q->sk);
+}
+
+/*
+ * Forward happens for data that gets sent from one macvlan
+ * endpoint to another one in bridge mode. We just take
+ * the skb and put it into the receive queue.
+ */
+static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
+{
+        struct macvtap_queue *q = macvtap_get_queue(dev, skb);
+        if (!q)
+                return -ENOLINK;
+
+        skb_queue_tail(&q->sk.sk_receive_queue, skb);
+        wake_up_interruptible_poll(q->sk.sk_sleep, POLLIN | POLLRDNORM | POLLRDBAND);
+        return 0;
+}
+
+/*
+ * Receive is for data from the external interface (lowerdev),
+ * in case of macvtap, we can treat that the same way as
+ * forward, which macvlan cannot.
+ */
+static int macvtap_receive(struct sk_buff *skb)
+{
+        skb_push(skb, ETH_HLEN);
+        return macvtap_forward(skb->dev, skb);
+}
+
+static int macvtap_newlink(struct net *src_net,
+                           struct net_device *dev,
+                           struct nlattr *tb[],
+                           struct nlattr *data[])
+{
+        struct device *classdev;
+        dev_t devt;
+        int err;
+
+        err = macvlan_common_newlink(src_net, dev, tb, data,
+                                     macvtap_receive, macvtap_forward);
+        if (err)
+                goto out;
+
+        devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
+
+        classdev = device_create(macvtap_class, &dev->dev, devt,
+                                 dev, "tap%d", dev->ifindex);
+        if (IS_ERR(classdev)) {
+                err = PTR_ERR(classdev);
+                macvtap_del_queues(dev);
+        }
+
+out:
+        return err;
+}
+
+static void macvtap_dellink(struct net_device *dev,
+                            struct list_head *head)
+{
+        device_destroy(macvtap_class,
+                       MKDEV(MAJOR(macvtap_major), dev->ifindex));
+
+        macvtap_del_queues(dev);
+        macvlan_dellink(dev, head);
+}
+
+static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
+        .kind           = "macvtap",
+        .newlink        = macvtap_newlink,
+        .dellink        = macvtap_dellink,
+};
+
+
+static void macvtap_sock_write_space(struct sock *sk)
+{
+        if (!sock_writeable(sk) ||
+            !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+                return;
+
+        if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
+                wake_up_interruptible_poll(sk->sk_sleep, POLLOUT | POLLWRNORM | POLLWRBAND);
+}
+
+static int macvtap_open(struct inode *inode, struct file *file)
+{
+        struct net *net = current->nsproxy->net_ns;
+        struct net_device *dev = dev_get_by_index(net, iminor(inode));
+        struct macvtap_queue *q;
+        int err;
+
+        err = -ENODEV;
+        if (!dev)
+                goto out;
+
+        /* check if this is a macvtap device */
+        err = -EINVAL;
+        if (dev->rtnl_link_ops != &macvtap_link_ops)
+                goto out;
+
+        err = -ENOMEM;
+        q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
+                                             &macvtap_proto);
+        if (!q)
+                goto out;
+
+        init_waitqueue_head(&q->sock.wait);
+        q->sock.type = SOCK_RAW;
+        q->sock.state = SS_CONNECTED;
+        q->sock.file = file;
+        q->sock.ops = &macvtap_socket_ops;
+        sock_init_data(&q->sock, &q->sk);
+        q->sk.sk_write_space = macvtap_sock_write_space;
+        q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
+
+        err = macvtap_set_queue(dev, file, q);
+        if (err)
+                sock_put(&q->sk);
+
+out:
+        if (dev)
+                dev_put(dev);
+
+        return err;
+}
+
+static int macvtap_release(struct inode *inode, struct file *file)
+{
+        struct macvtap_queue *q = file->private_data;
+        macvtap_put_queue(q);
+        return 0;
+}
+
+static unsigned int macvtap_poll(struct file *file, poll_table * wait)
+{
+        struct macvtap_queue *q = file->private_data;
+        unsigned int mask = POLLERR;
+
+        if (!q)
+                goto out;
+
+        mask = 0;
+        poll_wait(file, &q->sock.wait, wait);
+
+        if (!skb_queue_empty(&q->sk.sk_receive_queue))
+                mask |= POLLIN | POLLRDNORM;
+
+        if (sock_writeable(&q->sk) ||
+            (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
+             sock_writeable(&q->sk)))
+                mask |= POLLOUT | POLLWRNORM;
+
+out:
+        return mask;
+}
+
+static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
+                                                size_t len, size_t linear,
+                                                int noblock, int *err)
+{
+        struct sk_buff *skb;
+
+        /* 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 NULL;
+
+        skb_reserve(skb, prepad);
+        skb_put(skb, linear);
+        skb->data_len = len - linear;
+        skb->len += len - linear;
+
+        return skb;
+}
+
+/*
+ * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
+ * be shared with the tun/tap driver.
+ */
+static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
+                                     struct virtio_net_hdr *vnet_hdr)
+{
+        unsigned short gso_type = 0;
+        if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+                switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+                case VIRTIO_NET_HDR_GSO_TCPV4:
+                        gso_type = SKB_GSO_TCPV4;
+                        break;
+                case VIRTIO_NET_HDR_GSO_TCPV6:
+                        gso_type = SKB_GSO_TCPV6;
+                        break;
+                case VIRTIO_NET_HDR_GSO_UDP:
+                        gso_type = SKB_GSO_UDP;
+                        break;
+                default:
+                        return -EINVAL;
+                }
+
+                if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
+                        gso_type |= SKB_GSO_TCP_ECN;
+
+                if (vnet_hdr->gso_size == 0)
+                        return -EINVAL;
+        }
+
+        if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+                if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
+                                          vnet_hdr->csum_offset))
+                        return -EINVAL;
+        }
+
+        if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+                skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
+                skb_shinfo(skb)->gso_type = gso_type;
+
+                /* Header must be checked, and gso_segs computed. */
+                skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
+                skb_shinfo(skb)->gso_segs = 0;
+        }
+        return 0;
+}
+
+static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
+                                   struct virtio_net_hdr *vnet_hdr)
+{
+        memset(vnet_hdr, 0, sizeof(*vnet_hdr));
+
+        if (skb_is_gso(skb)) {
+                struct skb_shared_info *sinfo = skb_shinfo(skb);
+
+                /* This is a hint as to how much should be linear. */
+                vnet_hdr->hdr_len = skb_headlen(skb);
+                vnet_hdr->gso_size = sinfo->gso_size;
+                if (sinfo->gso_type & SKB_GSO_TCPV4)
+                        vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+                else if (sinfo->gso_type & SKB_GSO_TCPV6)
+                        vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+                else if (sinfo->gso_type & SKB_GSO_UDP)
+                        vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
+                else
+                        BUG();
+                if (sinfo->gso_type & SKB_GSO_TCP_ECN)
+                        vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
+        } else
+                vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
+
+        if (skb->ip_summed == CHECKSUM_PARTIAL) {
+                vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+                vnet_hdr->csum_start = skb->csum_start -
+                                        skb_headroom(skb);
+                vnet_hdr->csum_offset = skb->csum_offset;
+        } /* else everything is zero */
+
+        return 0;
+}
+
+
+/* Get packet from user space buffer */
+static ssize_t macvtap_get_user(struct macvtap_queue *q,
+                                const struct iovec *iv, size_t count,
+                                int noblock)
+{
+        struct sk_buff *skb;
+        struct macvlan_dev *vlan;
+        size_t len = count;
+        int err;
+        struct virtio_net_hdr vnet_hdr = { 0 };
+        int vnet_hdr_len = 0;
+
+        if (q->flags & IFF_VNET_HDR) {
+                vnet_hdr_len = sizeof(vnet_hdr);
+
+                err = -EINVAL;
+                if ((len -= vnet_hdr_len) < 0)
+                        goto err;
+
+                err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
+                                           vnet_hdr_len);
+                if (err < 0)
+                        goto err;
+                if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
+                     vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
+                                                        vnet_hdr.hdr_len)
+                        vnet_hdr.hdr_len = vnet_hdr.csum_start +
+                                                vnet_hdr.csum_offset + 2;
+                err = -EINVAL;
+                if (vnet_hdr.hdr_len > len)
+                        goto err;
+        }
+
+        err = -EINVAL;
+        if (unlikely(len < ETH_HLEN))
+                goto err;
+
+        skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, len, vnet_hdr.hdr_len,
+                                noblock, &err);
+        if (!skb)
+                goto err;
+
+        err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len);
+        if (err)
+                goto err_kfree;
+
+        skb_set_network_header(skb, ETH_HLEN);
+        skb_reset_mac_header(skb);
+        skb->protocol = eth_hdr(skb)->h_proto;
+
+        if (vnet_hdr_len) {
+                err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
+                if (err)
+                        goto err_kfree;
+        }
+
+        rcu_read_lock_bh();
+        vlan = rcu_dereference(q->vlan);
+        if (vlan)
+                macvlan_start_xmit(skb, vlan->dev);
+        else
+                kfree_skb(skb);
+        rcu_read_unlock_bh();
+
+        return count;
+
+err_kfree:
+        kfree_skb(skb);
+
+err:
+        rcu_read_lock_bh();
+        vlan = rcu_dereference(q->vlan);
+        if (vlan)
+                netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
+        rcu_read_unlock_bh();
+
+        return err;
+}
+
+static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
+                                 unsigned long count, loff_t pos)
+{
+        struct file *file = iocb->ki_filp;
+        ssize_t result = -ENOLINK;
+        struct macvtap_queue *q = file->private_data;
+
+        result = macvtap_get_user(q, iv, iov_length(iv, count),
+                              file->f_flags & O_NONBLOCK);
+        return result;
+}
+
+/* Put packet to the user space buffer */
+static ssize_t macvtap_put_user(struct macvtap_queue *q,
+                                const struct sk_buff *skb,
+                                const struct iovec *iv, int len)
+{
+        struct macvlan_dev *vlan;
+        int ret;
+        int vnet_hdr_len = 0;
+
+        if (q->flags & IFF_VNET_HDR) {
+                struct virtio_net_hdr vnet_hdr;
+                vnet_hdr_len = sizeof (vnet_hdr);
+                if ((len -= vnet_hdr_len) < 0)
+                        return -EINVAL;
+
+                ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
+                if (ret)
+                        return ret;
+
+                if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, vnet_hdr_len))
+                        return -EFAULT;
+        }
+
+        len = min_t(int, skb->len, len);
+
+        ret = skb_copy_datagram_const_iovec(skb, 0, iv, vnet_hdr_len, len);
+
+        rcu_read_lock_bh();
+        vlan = rcu_dereference(q->vlan);
+        if (vlan)
+                macvlan_count_rx(vlan, len, ret == 0, 0);
+        rcu_read_unlock_bh();
+
+        return ret ? ret : (len + vnet_hdr_len);
+}
+
+static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
+                               const struct iovec *iv, unsigned long len,
+                               int noblock)
+{
+        DECLARE_WAITQUEUE(wait, current);
+        struct sk_buff *skb;
+        ssize_t ret = 0;
+
+        add_wait_queue(q->sk.sk_sleep, &wait);
+        while (len) {
+                current->state = TASK_INTERRUPTIBLE;
+
+                /* Read frames from the queue */
+                skb = skb_dequeue(&q->sk.sk_receive_queue);
+                if (!skb) {
+                        if (noblock) {
+                                ret = -EAGAIN;
+                                break;
+                        }
+                        if (signal_pending(current)) {
+                                ret = -ERESTARTSYS;
+                                break;
+                        }
+                        /* Nothing to read, let's sleep */
+                        schedule();
+                        continue;
+                }
+                ret = macvtap_put_user(q, skb, iv, len);
+                kfree_skb(skb);
+                break;
+        }
+
+        current->state = TASK_RUNNING;
+        remove_wait_queue(q->sk.sk_sleep, &wait);
+        return ret;
+}
+
+static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
+                                unsigned long count, loff_t pos)
+{
+        struct file *file = iocb->ki_filp;
+        struct macvtap_queue *q = file->private_data;
+        ssize_t len, ret = 0;
+
+        len = iov_length(iv, count);
+        if (len < 0) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
+        ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
+out:
+        return ret;
+}
+
+/*
+ * provide compatibility with generic tun/tap interface
+ */
+static long macvtap_ioctl(struct file *file, unsigned int cmd,
+                          unsigned long arg)
+{
+        struct macvtap_queue *q = file->private_data;
+        struct macvlan_dev *vlan;
+        void __user *argp = (void __user *)arg;
+        struct ifreq __user *ifr = argp;
+        unsigned int __user *up = argp;
+        unsigned int u;
+        int ret;
+
+        switch (cmd) {
+        case TUNSETIFF:
+                /* ignore the name, just look at flags */
+                if (get_user(u, &ifr->ifr_flags))
+                        return -EFAULT;
+
+                ret = 0;
+                if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
+                        ret = -EINVAL;
+                else
+                        q->flags = u;
+
+                return ret;
+
+        case TUNGETIFF:
+                rcu_read_lock_bh();
+                vlan = rcu_dereference(q->vlan);
+                if (vlan)
+                        dev_hold(vlan->dev);
+                rcu_read_unlock_bh();
+
+                if (!vlan)
+                        return -ENOLINK;
+
+                ret = 0;
+                if (copy_to_user(&ifr->ifr_name, q->vlan->dev->name, IFNAMSIZ) ||
+                    put_user(q->flags, &ifr->ifr_flags))
+                        ret = -EFAULT;
+                dev_put(vlan->dev);
+                return ret;
+
+        case TUNGETFEATURES:
+                if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
+                        return -EFAULT;
+                return 0;
+
+        case TUNSETSNDBUF:
+                if (get_user(u, up))
+                        return -EFAULT;
+
+                q->sk.sk_sndbuf = u;
+                return 0;
+
+        case TUNSETOFFLOAD:
+                /* let the user check for future flags */
+                if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
+                            TUN_F_TSO_ECN | TUN_F_UFO))
+                        return -EINVAL;
+
+                /* TODO: only accept frames with the features that
+                         got enabled for forwarded frames */
+                if (!(q->flags & IFF_VNET_HDR))
+                        return  -EINVAL;
+                return 0;
+
+        default:
+                return -EINVAL;
+        }
+}
+
+#ifdef CONFIG_COMPAT
+static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
+                                 unsigned long arg)
+{
+        return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
+}
+#endif
+
+static const struct file_operations macvtap_fops = {
+        .owner          = THIS_MODULE,
+        .open           = macvtap_open,
+        .release        = macvtap_release,
+        .aio_read       = macvtap_aio_read,
+        .aio_write      = macvtap_aio_write,
+        .poll           = macvtap_poll,
+        .llseek         = no_llseek,
+        .unlocked_ioctl = macvtap_ioctl,
+#ifdef CONFIG_COMPAT
+        .compat_ioctl   = macvtap_compat_ioctl,
+#endif
+};
+
+static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
+                           struct msghdr *m, size_t total_len)
+{
+        struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
+        return macvtap_get_user(q, m->msg_iov, total_len,
+                            m->msg_flags & MSG_DONTWAIT);
+}
+
+static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
+                           struct msghdr *m, size_t total_len,
+                           int flags)
+{
+        struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
+        int ret;
+        if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
+                return -EINVAL;
+        ret = macvtap_do_read(q, 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;
+}
+
+/* Ops structure to mimic raw sockets with tun */
+static const struct proto_ops macvtap_socket_ops = {
+        .sendmsg = macvtap_sendmsg,
+        .recvmsg = macvtap_recvmsg,
+};
+
+/* 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 *macvtap_get_socket(struct file *file)
+{
+        struct macvtap_queue *q;
+        if (file->f_op != &macvtap_fops)
+                return ERR_PTR(-EINVAL);
+        q = file->private_data;
+        if (!q)
+                return ERR_PTR(-EBADFD);
+        return &q->sock;
+}
+EXPORT_SYMBOL_GPL(macvtap_get_socket);
+
+static int macvtap_init(void)
+{
+        int err;
+
+        err = alloc_chrdev_region(&macvtap_major, 0,
+                                MACVTAP_NUM_DEVS, "macvtap");
+        if (err)
+                goto out1;
+
+        cdev_init(&macvtap_cdev, &macvtap_fops);
+        err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
+        if (err)
+                goto out2;
+
+        macvtap_class = class_create(THIS_MODULE, "macvtap");
+        if (IS_ERR(macvtap_class)) {
+                err = PTR_ERR(macvtap_class);
+                goto out3;
+        }
+
+        err = macvlan_link_register(&macvtap_link_ops);
+        if (err)
+                goto out4;
+
+        return 0;
+
+out4:
+        class_unregister(macvtap_class);
+out3:
+        cdev_del(&macvtap_cdev);
+out2:
+        unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+out1:
+        return err;
+}
+module_init(macvtap_init);
+
+static void macvtap_exit(void)
+{
+        rtnl_link_unregister(&macvtap_link_ops);
+        class_unregister(macvtap_class);
+        cdev_del(&macvtap_cdev);
+        unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+}
+module_exit(macvtap_exit);
+
+MODULE_ALIAS_RTNL_LINK("macvtap");
+MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
+MODULE_LICENSE("GPL");