Moved, renamed, and deleted files

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

1 files changed, 1157 insertions, 0 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
new file mode 100644
index 00000000..c1d602d5
--- /dev/null
+++ b/drivers/net/macvtap.c
@@ -0,0 +1,1157 @@
+#include <linux/etherdevice.h>
+#include <linux/if_macvlan.h>
+#include <linux/if_vlan.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/idr.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 socket_wq wq;
+	int vnet_hdr_sz;
+	struct macvlan_dev __rcu *vlan;
+	struct file *file;
+	unsigned int flags;
+};
+
+static struct proto macvtap_proto = {
+	.name = "macvtap",
+	.owner = THIS_MODULE,
+	.obj_size = sizeof (struct macvtap_queue),
+};
+
+/*
+ * Variables for dealing with macvtaps device numbers.
+ */
+static dev_t macvtap_major;
+#define MACVTAP_NUM_DEVS (1U << MINORBITS)
+static DEFINE_MUTEX(minor_lock);
+static DEFINE_IDR(minor_idr);
+
+#define GOODCOPY_LEN 128
+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);
+
+/*
+ * get_slot: return a [unused/occupied] slot in vlan->taps[]:
+ *	- if 'q' is NULL, return the first empty slot;
+ *	- otherwise, return the slot this pointer occupies.
+ */
+static int get_slot(struct macvlan_dev *vlan, struct macvtap_queue *q)
+{
+	int i;
+
+	for (i = 0; i < MAX_MACVTAP_QUEUES; i++) {
+		if (rcu_dereference(vlan->taps[i]) == q)
+			return i;
+	}
+
+	/* Should never happen */
+	BUG_ON(1);
+}
+
+static int macvtap_set_queue(struct net_device *dev, struct file *file,
+				struct macvtap_queue *q)
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+	int index;
+	int err = -EBUSY;
+
+	spin_lock(&macvtap_lock);
+	if (vlan->numvtaps == MAX_MACVTAP_QUEUES)
+		goto out;
+
+	err = 0;
+	index = get_slot(vlan, NULL);
+	rcu_assign_pointer(q->vlan, vlan);
+	rcu_assign_pointer(vlan->taps[index], q);
+	sock_hold(&q->sk);
+
+	q->file = file;
+	file->private_data = q;
+
+	vlan->numvtaps++;
+
+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_protected(q->vlan,
+					 lockdep_is_held(&macvtap_lock));
+	if (vlan) {
+		int index = get_slot(vlan, q);
+
+		RCU_INIT_POINTER(vlan->taps[index], NULL);
+		RCU_INIT_POINTER(q->vlan, NULL);
+		sock_put(&q->sk);
+		--vlan->numvtaps;
+	}
+
+	spin_unlock(&macvtap_lock);
+
+	synchronize_rcu();
+	sock_put(&q->sk);
+}
+
+/*
+ * Select a queue based on the rxq of the device on which this packet
+ * arrived. If the incoming device is not mq, calculate a flow hash
+ * to select a queue. If all fails, find the first available queue.
+ * Cache vlan->numvtaps since it can become zero during the execution
+ * of this function.
+ */
+static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
+					       struct sk_buff *skb)
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+	struct macvtap_queue *tap = NULL;
+	int numvtaps = vlan->numvtaps;
+	__u32 rxq;
+
+	if (!numvtaps)
+		goto out;
+
+	/* Check if we can use flow to select a queue */
+	rxq = skb_get_rxhash(skb);
+	if (rxq) {
+		tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
+		if (tap)
+			goto out;
+	}
+
+	if (likely(skb_rx_queue_recorded(skb))) {
+		rxq = skb_get_rx_queue(skb);
+
+		while (unlikely(rxq >= numvtaps))
+			rxq -= numvtaps;
+
+		tap = rcu_dereference(vlan->taps[rxq]);
+		if (tap)
+			goto out;
+	}
+
+	/* Everything failed - find first available queue */
+	for (rxq = 0; rxq < MAX_MACVTAP_QUEUES; rxq++) {
+		tap = rcu_dereference(vlan->taps[rxq]);
+		if (tap)
+			break;
+	}
+
+out:
+	return tap;
+}
+
+/*
+ * The net_device is going away, give up the reference
+ * that it holds on all queues 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, *qlist[MAX_MACVTAP_QUEUES];
+	int i, j = 0;
+
+	/* macvtap_put_queue can free some slots, so go through all slots */
+	spin_lock(&macvtap_lock);
+	for (i = 0; i < MAX_MACVTAP_QUEUES && vlan->numvtaps; i++) {
+		q = rcu_dereference_protected(vlan->taps[i],
+					      lockdep_is_held(&macvtap_lock));
+		if (q) {
+			qlist[j++] = q;
+			RCU_INIT_POINTER(vlan->taps[i], NULL);
+			RCU_INIT_POINTER(q->vlan, NULL);
+			vlan->numvtaps--;
+		}
+	}
+	BUG_ON(vlan->numvtaps != 0);
+	/* guarantee that any future macvtap_set_queue will fail */
+	vlan->numvtaps = MAX_MACVTAP_QUEUES;
+	spin_unlock(&macvtap_lock);
+
+	synchronize_rcu();
+
+	for (--j; j >= 0; j--)
+		sock_put(&qlist[j]->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)
+		goto drop;
+
+	if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
+		goto drop;
+
+	skb_queue_tail(&q->sk.sk_receive_queue, skb);
+	wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
+	return NET_RX_SUCCESS;
+
+drop:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+/*
+ * 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_get_minor(struct macvlan_dev *vlan)
+{
+	int retval = -ENOMEM;
+	int id;
+
+	mutex_lock(&minor_lock);
+	if (idr_pre_get(&minor_idr, GFP_KERNEL) == 0)
+		goto exit;
+
+	retval = idr_get_new_above(&minor_idr, vlan, 1, &id);
+	if (retval < 0) {
+		if (retval == -EAGAIN)
+			retval = -ENOMEM;
+		goto exit;
+	}
+	if (id < MACVTAP_NUM_DEVS) {
+		vlan->minor = id;
+	} else {
+		printk(KERN_ERR "too many macvtap devices\n");
+		retval = -EINVAL;
+		idr_remove(&minor_idr, id);
+	}
+exit:
+	mutex_unlock(&minor_lock);
+	return retval;
+}
+
+static void macvtap_free_minor(struct macvlan_dev *vlan)
+{
+	mutex_lock(&minor_lock);
+	if (vlan->minor) {
+		idr_remove(&minor_idr, vlan->minor);
+		vlan->minor = 0;
+	}
+	mutex_unlock(&minor_lock);
+}
+
+static struct net_device *dev_get_by_macvtap_minor(int minor)
+{
+	struct net_device *dev = NULL;
+	struct macvlan_dev *vlan;
+
+	mutex_lock(&minor_lock);
+	vlan = idr_find(&minor_idr, minor);
+	if (vlan) {
+		dev = vlan->dev;
+		dev_hold(dev);
+	}
+	mutex_unlock(&minor_lock);
+	return dev;
+}
+
+static int macvtap_newlink(struct net *src_net,
+			   struct net_device *dev,
+			   struct nlattr *tb[],
+			   struct nlattr *data[])
+{
+	/* Don't put anything that may fail after macvlan_common_newlink
+	 * because we can't undo what it does.
+	 */
+	return macvlan_common_newlink(src_net, dev, tb, data,
+				      macvtap_receive, macvtap_forward);
+}
+
+static void macvtap_dellink(struct net_device *dev,
+			    struct list_head *head)
+{
+	macvtap_del_queues(dev);
+	macvlan_dellink(dev, head);
+}
+
+static void macvtap_setup(struct net_device *dev)
+{
+	macvlan_common_setup(dev);
+	dev->tx_queue_len = TUN_READQ_SIZE;
+}
+
+static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
+	.kind		= "macvtap",
+	.setup		= macvtap_setup,
+	.newlink	= macvtap_newlink,
+	.dellink	= macvtap_dellink,
+};
+
+
+static void macvtap_sock_write_space(struct sock *sk)
+{
+	wait_queue_head_t *wqueue;
+
+	if (!sock_writeable(sk) ||
+	    !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
+		return;
+
+	wqueue = sk_sleep(sk);
+	if (wqueue && waitqueue_active(wqueue))
+		wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
+}
+
+static void macvtap_sock_destruct(struct sock *sk)
+{
+	skb_queue_purge(&sk->sk_receive_queue);
+}
+
+static int macvtap_open(struct inode *inode, struct file *file)
+{
+	struct net *net = current->nsproxy->net_ns;
+	struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode));
+	struct macvtap_queue *q;
+	int err;
+
+	err = -ENODEV;
+	if (!dev)
+		goto out;
+
+	err = -ENOMEM;
+	q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
+					     &macvtap_proto);
+	if (!q)
+		goto out;
+
+	q->sock.wq = &q->wq;
+	init_waitqueue_head(&q->wq.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->sk.sk_destruct = macvtap_sock_destruct;
+	q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
+	q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
+
+	/*
+	 * so far only KVM virtio_net uses macvtap, enable zero copy between
+	 * guest kernel and host kernel when lower device supports zerocopy
+	 *
+	 * The macvlan supports zerocopy iff the lower device supports zero
+	 * copy so we don't have to look at the lower device directly.
+	 */
+	if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
+		sock_set_flag(&q->sk, SOCK_ZEROCOPY);
+
+	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->wq.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;
+}
+
+/* set skb frags from iovec, this can move to core network code for reuse */
+static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
+				  int offset, size_t count)
+{
+	int len = iov_length(from, count) - offset;
+	int copy = skb_headlen(skb);
+	int size, offset1 = 0;
+	int i = 0;
+
+	/* Skip over from offset */
+	while (count && (offset >= from->iov_len)) {
+		offset -= from->iov_len;
+		++from;
+		--count;
+	}
+
+	/* copy up to skb headlen */
+	while (count && (copy > 0)) {
+		size = min_t(unsigned int, copy, from->iov_len - offset);
+		if (copy_from_user(skb->data + offset1, from->iov_base + offset,
+				   size))
+			return -EFAULT;
+		if (copy > size) {
+			++from;
+			--count;
+		}
+		copy -= size;
+		offset1 += size;
+		offset = 0;
+	}
+
+	if (len == offset1)
+		return 0;
+
+	while (count--) {
+		struct page *page[MAX_SKB_FRAGS];
+		int num_pages;
+		unsigned long base;
+
+		len = from->iov_len - offset1;
+		if (!len) {
+			offset1 = 0;
+			++from;
+			continue;
+		}
+		base = (unsigned long)from->iov_base + offset1;
+		size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
+		if (i + size > MAX_SKB_FRAGS)
+			return -EMSGSIZE;
+		num_pages = get_user_pages_fast(base, size, 0, &page[i]);
+		if (num_pages != size)
+			/* put_page is in skb free */
+			return -EFAULT;
+		skb->data_len += len;
+		skb->len += len;
+		skb->truesize += len;
+		atomic_add(len, &skb->sk->sk_wmem_alloc);
+		while (len) {
+			int off = base & ~PAGE_MASK;
+			int size = min_t(int, len, PAGE_SIZE - off);
+			__skb_fill_page_desc(skb, i, page[i], off, size);
+			skb_shinfo(skb)->nr_frags++;
+			/* increase sk_wmem_alloc */
+			base += size;
+			len -= size;
+			i++;
+		}
+		offset1 = 0;
+		++from;
+	}
+	return 0;
+}
+
+/*
+ * 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_checksum_start_offset(skb);
+		vnet_hdr->csum_offset = skb->csum_offset;
+	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
+		vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
+	} /* else everything is zero */
+
+	return 0;
+}
+
+
+/* Get packet from user space buffer */
+static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
+				const struct iovec *iv, unsigned long total_len,
+				size_t count, int noblock)
+{
+	struct sk_buff *skb;
+	struct macvlan_dev *vlan;
+	unsigned long len = total_len;
+	int err;
+	struct virtio_net_hdr vnet_hdr = { 0 };
+	int vnet_hdr_len = 0;
+	int copylen = 0;
+	bool zerocopy = false;
+
+	if (q->flags & IFF_VNET_HDR) {
+		vnet_hdr_len = q->vnet_hdr_sz;
+
+		err = -EINVAL;
+		if (len < vnet_hdr_len)
+			goto err;
+		len -= vnet_hdr_len;
+
+		err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
+					   sizeof(vnet_hdr));
+		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;
+
+	err = -EMSGSIZE;
+	if (unlikely(count > UIO_MAXIOV))
+		goto err;
+
+	if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY))
+		zerocopy = true;
+
+	if (zerocopy) {
+		/* Userspace may produce vectors with count greater than
+		 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
+		 * to let the rest of data to be fit in the frags.
+		 */
+		if (count > MAX_SKB_FRAGS) {
+			copylen = iov_length(iv, count - MAX_SKB_FRAGS);
+			if (copylen < vnet_hdr_len)
+				copylen = 0;
+			else
+				copylen -= vnet_hdr_len;
+		}
+		/* There are 256 bytes to be copied in skb, so there is enough
+		 * room for skb expand head in case it is used.
+		 * The rest buffer is mapped from userspace.
+		 */
+		if (copylen < vnet_hdr.hdr_len)
+			copylen = vnet_hdr.hdr_len;
+		if (!copylen)
+			copylen = GOODCOPY_LEN;
+	} else
+		copylen = len;
+
+	skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen,
+				vnet_hdr.hdr_len, noblock, &err);
+	if (!skb)
+		goto err;
+
+	if (zerocopy) {
+		err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);
+		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
+	} else
+		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_bh(q->vlan);
+	/* copy skb_ubuf_info for callback when skb has no error */
+	if (zerocopy)
+		skb_shinfo(skb)->destructor_arg = m->msg_control;
+	if (vlan)
+		macvlan_start_xmit(skb, vlan->dev);
+	else
+		kfree_skb(skb);
+	rcu_read_unlock_bh();
+
+	return total_len;
+
+err_kfree:
+	kfree_skb(skb);
+
+err:
+	rcu_read_lock_bh();
+	vlan = rcu_dereference_bh(q->vlan);
+	if (vlan)
+		vlan->dev->stats.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, NULL, iv, iov_length(iv, count), 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;
+	int vlan_offset = 0;
+	int copied;
+
+	if (q->flags & IFF_VNET_HDR) {
+		struct virtio_net_hdr vnet_hdr;
+		vnet_hdr_len = q->vnet_hdr_sz;
+		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, sizeof(vnet_hdr)))
+			return -EFAULT;
+	}
+	copied = vnet_hdr_len;
+
+	if (!vlan_tx_tag_present(skb))
+		len = min_t(int, skb->len, len);
+	else {
+		int copy;
+		struct {
+			__be16 h_vlan_proto;
+			__be16 h_vlan_TCI;
+		} veth;
+		veth.h_vlan_proto = htons(ETH_P_8021Q);
+		veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));
+
+		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
+		len = min_t(int, skb->len + VLAN_HLEN, len);
+
+		copy = min_t(int, vlan_offset, len);
+		ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
+		len -= copy;
+		copied += copy;
+		if (ret || !len)
+			goto done;
+
+		copy = min_t(int, sizeof(veth), len);
+		ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
+		len -= copy;
+		copied += copy;
+		if (ret || !len)
+			goto done;
+	}
+
+	ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
+	copied += len;
+
+done:
+	rcu_read_lock_bh();
+	vlan = rcu_dereference_bh(q->vlan);
+	if (vlan)
+		macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0);
+	rcu_read_unlock_bh();
+
+	return ret ? ret : copied;
+}
+
+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(sk_sleep(&q->sk), &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(sk_sleep(&q->sk), &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 __user *sp = argp;
+	int s;
+	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_bh(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, 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 TUNGETVNETHDRSZ:
+		s = q->vnet_hdr_sz;
+		if (put_user(s, sp))
+			return -EFAULT;
+		return 0;
+
+	case TUNSETVNETHDRSZ:
+		if (get_user(s, sp))
+			return -EFAULT;
+		if (s < (int)sizeof(struct virtio_net_hdr))
+			return -EINVAL;
+
+		q->vnet_hdr_sz = s;
+		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, m->msg_iov, total_len, m->msg_iovlen,
+			    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_device_event(struct notifier_block *unused,
+				unsigned long event, void *ptr)
+{
+	struct net_device *dev = ptr;
+	struct macvlan_dev *vlan;
+	struct device *classdev;
+	dev_t devt;
+	int err;
+
+	if (dev->rtnl_link_ops != &macvtap_link_ops)
+		return NOTIFY_DONE;
+
+	vlan = netdev_priv(dev);
+
+	switch (event) {
+	case NETDEV_REGISTER:
+		/* Create the device node here after the network device has
+		 * been registered but before register_netdevice has
+		 * finished running.
+		 */
+		err = macvtap_get_minor(vlan);
+		if (err)
+			return notifier_from_errno(err);
+
+		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+		classdev = device_create(macvtap_class, &dev->dev, devt,
+					 dev, "tap%d", dev->ifindex);
+		if (IS_ERR(classdev)) {
+			macvtap_free_minor(vlan);
+			return notifier_from_errno(PTR_ERR(classdev));
+		}
+		break;
+	case NETDEV_UNREGISTER:
+		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+		device_destroy(macvtap_class, devt);
+		macvtap_free_minor(vlan);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block macvtap_notifier_block __read_mostly = {
+	.notifier_call	= macvtap_device_event,
+};
+
+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 = register_netdevice_notifier(&macvtap_notifier_block);
+	if (err)
+		goto out4;
+
+	err = macvlan_link_register(&macvtap_link_ops);
+	if (err)
+		goto out5;
+
+	return 0;
+
+out5:
+	unregister_netdevice_notifier(&macvtap_notifier_block);
+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);
+	unregister_netdevice_notifier(&macvtap_notifier_block);
+	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");