macvtap.c 26.2 KB
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#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>
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#include <linux/slab.h>
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#include <linux/init.h>
#include <linux/wait.h>
#include <linux/cdev.h>
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#include <linux/idr.h>
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#include <linux/fs.h>

#include <net/net_namespace.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
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#include <linux/virtio_net.h>
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/*
 * 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;
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	struct socket_wq wq;
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	int vnet_hdr_sz;
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	struct macvlan_dev __rcu *vlan;
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	struct file *file;
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	unsigned int flags;
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};

static struct proto macvtap_proto = {
	.name = "macvtap",
	.owner = THIS_MODULE,
	.obj_size = sizeof (struct macvtap_queue),
};

/*
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 * Variables for dealing with macvtaps device numbers.
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 */
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static dev_t macvtap_major;
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#define MACVTAP_NUM_DEVS (1U << MINORBITS)
static DEFINE_MUTEX(minor_lock);
static DEFINE_IDR(minor_idr);

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#define GOODCOPY_LEN 128
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static struct class *macvtap_class;
static struct cdev macvtap_cdev;

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static const struct proto_ops macvtap_socket_ops;

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/*
 * RCU usage:
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 * 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.
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 *
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 * 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.
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 *
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 * 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.
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 */
static DEFINE_SPINLOCK(macvtap_lock);

/*
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 * 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.
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 */
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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);
}

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static int macvtap_set_queue(struct net_device *dev, struct file *file,
				struct macvtap_queue *q)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
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	int index;
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	int err = -EBUSY;

	spin_lock(&macvtap_lock);
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	if (vlan->numvtaps == MAX_MACVTAP_QUEUES)
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		goto out;

	err = 0;
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	index = get_slot(vlan, NULL);
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	rcu_assign_pointer(q->vlan, vlan);
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	rcu_assign_pointer(vlan->taps[index], q);
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	sock_hold(&q->sk);
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	q->file = file;
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	file->private_data = q;
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	vlan->numvtaps++;

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out:
	spin_unlock(&macvtap_lock);
	return err;
}

/*
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 * 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.
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 *
 * Using the spinlock makes sure that we don't get
 * to the queue again after destroying it.
 */
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static void macvtap_put_queue(struct macvtap_queue *q)
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{
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	struct macvlan_dev *vlan;
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	spin_lock(&macvtap_lock);
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	vlan = rcu_dereference_protected(q->vlan,
					 lockdep_is_held(&macvtap_lock));
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	if (vlan) {
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		int index = get_slot(vlan, q);

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		RCU_INIT_POINTER(vlan->taps[index], NULL);
		RCU_INIT_POINTER(q->vlan, NULL);
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		sock_put(&q->sk);
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		--vlan->numvtaps;
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	}

	spin_unlock(&macvtap_lock);

	synchronize_rcu();
	sock_put(&q->sk);
}

/*
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 * 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.
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 */
static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
					       struct sk_buff *skb)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
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	struct macvtap_queue *tap = NULL;
	int numvtaps = vlan->numvtaps;
	__u32 rxq;

	if (!numvtaps)
		goto out;

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	/* 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;
	}

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	if (likely(skb_rx_queue_recorded(skb))) {
		rxq = skb_get_rx_queue(skb);
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		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;
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}

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/*
 * The net_device is going away, give up the reference
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 * that it holds on all queues and safely set the pointer
 * from the queues to NULL.
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 */
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static void macvtap_del_queues(struct net_device *dev)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
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	struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES];
	int i, j = 0;
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	/* macvtap_put_queue can free some slots, so go through all slots */
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	spin_lock(&macvtap_lock);
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	for (i = 0; i < MAX_MACVTAP_QUEUES && vlan->numvtaps; i++) {
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		q = rcu_dereference_protected(vlan->taps[i],
					      lockdep_is_held(&macvtap_lock));
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		if (q) {
			qlist[j++] = q;
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			RCU_INIT_POINTER(vlan->taps[i], NULL);
			RCU_INIT_POINTER(q->vlan, NULL);
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			vlan->numvtaps--;
		}
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	}
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	BUG_ON(vlan->numvtaps != 0);
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	/* guarantee that any future macvtap_set_queue will fail */
	vlan->numvtaps = MAX_MACVTAP_QUEUES;
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	spin_unlock(&macvtap_lock);

	synchronize_rcu();
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	for (--j; j >= 0; j--)
		sock_put(&qlist[j]->sk);
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}

/*
 * 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)
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		goto drop;

	if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
		goto drop;
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	skb_queue_tail(&q->sk.sk_receive_queue, skb);
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	wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
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	return NET_RX_SUCCESS;

drop:
	kfree_skb(skb);
	return NET_RX_DROP;
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}

/*
 * 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);
}

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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;
}

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static int macvtap_newlink(struct net *src_net,
			   struct net_device *dev,
			   struct nlattr *tb[],
			   struct nlattr *data[])
{
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	/* 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);
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}

static void macvtap_dellink(struct net_device *dev,
			    struct list_head *head)
{
	macvtap_del_queues(dev);
	macvlan_dellink(dev, head);
}

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static void macvtap_setup(struct net_device *dev)
{
	macvlan_common_setup(dev);
	dev->tx_queue_len = TUN_READQ_SIZE;
}

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static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
	.kind		= "macvtap",
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	.setup		= macvtap_setup,
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	.newlink	= macvtap_newlink,
	.dellink	= macvtap_dellink,
};


static void macvtap_sock_write_space(struct sock *sk)
{
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	wait_queue_head_t *wqueue;

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	if (!sock_writeable(sk) ||
	    !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
		return;

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	wqueue = sk_sleep(sk);
	if (wqueue && waitqueue_active(wqueue))
		wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
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}

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static void macvtap_sock_destruct(struct sock *sk)
{
	skb_queue_purge(&sk->sk_receive_queue);
}

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static int macvtap_open(struct inode *inode, struct file *file)
{
	struct net *net = current->nsproxy->net_ns;
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	struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode));
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	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;

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	q->sock.wq = &q->wq;
	init_waitqueue_head(&q->wq.wait);
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	q->sock.type = SOCK_RAW;
	q->sock.state = SS_CONNECTED;
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	q->sock.file = file;
	q->sock.ops = &macvtap_socket_ops;
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	sock_init_data(&q->sock, &q->sk);
	q->sk.sk_write_space = macvtap_sock_write_space;
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	q->sk.sk_destruct = macvtap_sock_destruct;
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	q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
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	q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
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	/*
	 * so far only KVM virtio_net uses macvtap, enable zero copy between
	 * guest kernel and host kernel when lower device supports zerocopy
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	 *
	 * The macvlan supports zerocopy iff the lower device supports zero
	 * copy so we don't have to look at the lower device directly.
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	 */
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	if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
		sock_set_flag(&q->sk, SOCK_ZEROCOPY);
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	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)
{
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	struct macvtap_queue *q = file->private_data;
	macvtap_put_queue(q);
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	return 0;
}

static unsigned int macvtap_poll(struct file *file, poll_table * wait)
{
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	struct macvtap_queue *q = file->private_data;
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	unsigned int mask = POLLERR;

	if (!q)
		goto out;

	mask = 0;
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	poll_wait(file, &q->wq.wait, wait);
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	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;
}

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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;
}

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/* 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;
		num_pages = get_user_pages_fast(base, size, 0, &page[i]);
		if ((num_pages != size) ||
		    (num_pages > MAX_SKB_FRAGS - skb_shinfo(skb)->nr_frags))
			/* 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) {
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			int off = base & ~PAGE_MASK;
			int size = min_t(int, len, PAGE_SIZE - off);
			__skb_fill_page_desc(skb, i, page[i], off, size);
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			skb_shinfo(skb)->nr_frags++;
			/* increase sk_wmem_alloc */
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			base += size;
			len -= size;
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			i++;
		}
		offset1 = 0;
		++from;
	}
	return 0;
}

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/*
 * 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;
628
		vnet_hdr->csum_start = skb_checksum_start_offset(skb);
629
		vnet_hdr->csum_offset = skb->csum_offset;
630 631
	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
		vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
632 633 634 635 636 637
	} /* else everything is zero */

	return 0;
}


A
Arnd Bergmann 已提交
638
/* Get packet from user space buffer */
639 640 641
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)
A
Arnd Bergmann 已提交
642 643
{
	struct sk_buff *skb;
644
	struct macvlan_dev *vlan;
645
	unsigned long len = total_len;
A
Arnd Bergmann 已提交
646
	int err;
647 648
	struct virtio_net_hdr vnet_hdr = { 0 };
	int vnet_hdr_len = 0;
649 650
	int copylen;
	bool zerocopy = false;
651 652

	if (q->flags & IFF_VNET_HDR) {
653
		vnet_hdr_len = q->vnet_hdr_sz;
654 655

		err = -EINVAL;
656
		if (len < vnet_hdr_len)
657
			goto err;
658
		len -= vnet_hdr_len;
659 660

		err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
661
					   sizeof(vnet_hdr));
662 663 664 665 666 667 668 669 670 671 672
		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;
	}
A
Arnd Bergmann 已提交
673

674
	err = -EINVAL;
A
Arnd Bergmann 已提交
675
	if (unlikely(len < ETH_HLEN))
676
		goto err;
A
Arnd Bergmann 已提交
677

678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693
	if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY))
		zerocopy = true;

	if (zerocopy) {
		/* 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.
		 */
		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);
694 695
	if (!skb)
		goto err;
A
Arnd Bergmann 已提交
696

697 698 699 700 701 702
	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);
703
	if (err)
704
		goto err_kfree;
A
Arnd Bergmann 已提交
705 706

	skb_set_network_header(skb, ETH_HLEN);
707 708 709 710 711 712 713 714 715
	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;
	}

716
	rcu_read_lock_bh();
717
	vlan = rcu_dereference_bh(q->vlan);
718 719 720
	/* copy skb_ubuf_info for callback when skb has no error */
	if (zerocopy)
		skb_shinfo(skb)->destructor_arg = m->msg_control;
721 722 723 724 725
	if (vlan)
		macvlan_start_xmit(skb, vlan->dev);
	else
		kfree_skb(skb);
	rcu_read_unlock_bh();
A
Arnd Bergmann 已提交
726

727
	return total_len;
728

729 730 731
err_kfree:
	kfree_skb(skb);

732 733
err:
	rcu_read_lock_bh();
734
	vlan = rcu_dereference_bh(q->vlan);
735
	if (vlan)
E
Eric Dumazet 已提交
736
		vlan->dev->stats.tx_dropped++;
737 738 739
	rcu_read_unlock_bh();

	return err;
A
Arnd Bergmann 已提交
740 741 742 743 744 745 746
}

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;
747
	struct macvtap_queue *q = file->private_data;
A
Arnd Bergmann 已提交
748

749 750
	result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count,
				  file->f_flags & O_NONBLOCK);
A
Arnd Bergmann 已提交
751 752 753 754 755 756 757 758
	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)
{
759
	struct macvlan_dev *vlan;
A
Arnd Bergmann 已提交
760
	int ret;
761 762 763 764
	int vnet_hdr_len = 0;

	if (q->flags & IFF_VNET_HDR) {
		struct virtio_net_hdr vnet_hdr;
765
		vnet_hdr_len = q->vnet_hdr_sz;
766 767 768 769 770 771 772
		if ((len -= vnet_hdr_len) < 0)
			return -EINVAL;

		ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
		if (ret)
			return ret;

773
		if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr)))
774 775
			return -EFAULT;
	}
A
Arnd Bergmann 已提交
776 777 778

	len = min_t(int, skb->len, len);

779
	ret = skb_copy_datagram_const_iovec(skb, 0, iv, vnet_hdr_len, len);
A
Arnd Bergmann 已提交
780

781
	rcu_read_lock_bh();
782
	vlan = rcu_dereference_bh(q->vlan);
A
Arnd Bergmann 已提交
783 784
	if (vlan)
		macvlan_count_rx(vlan, len, ret == 0, 0);
785
	rcu_read_unlock_bh();
A
Arnd Bergmann 已提交
786

787
	return ret ? ret : (len + vnet_hdr_len);
A
Arnd Bergmann 已提交
788 789
}

A
Arnd Bergmann 已提交
790 791 792
static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
			       const struct iovec *iv, unsigned long len,
			       int noblock)
A
Arnd Bergmann 已提交
793 794 795
{
	DECLARE_WAITQUEUE(wait, current);
	struct sk_buff *skb;
A
Arnd Bergmann 已提交
796
	ssize_t ret = 0;
A
Arnd Bergmann 已提交
797

E
Eric Dumazet 已提交
798
	add_wait_queue(sk_sleep(&q->sk), &wait);
A
Arnd Bergmann 已提交
799 800 801 802 803 804
	while (len) {
		current->state = TASK_INTERRUPTIBLE;

		/* Read frames from the queue */
		skb = skb_dequeue(&q->sk.sk_receive_queue);
		if (!skb) {
A
Arnd Bergmann 已提交
805
			if (noblock) {
A
Arnd Bergmann 已提交
806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822
				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;
E
Eric Dumazet 已提交
823
	remove_wait_queue(sk_sleep(&q->sk), &wait);
A
Arnd Bergmann 已提交
824 825 826 827 828 829 830 831 832
	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;
A
Arnd Bergmann 已提交
833

A
Arnd Bergmann 已提交
834 835 836 837 838 839 840 841
	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? */
A
Arnd Bergmann 已提交
842 843 844 845 846 847 848 849 850 851
out:
	return ret;
}

/*
 * provide compatibility with generic tun/tap interface
 */
static long macvtap_ioctl(struct file *file, unsigned int cmd,
			  unsigned long arg)
{
852 853
	struct macvtap_queue *q = file->private_data;
	struct macvlan_dev *vlan;
A
Arnd Bergmann 已提交
854 855 856 857
	void __user *argp = (void __user *)arg;
	struct ifreq __user *ifr = argp;
	unsigned int __user *up = argp;
	unsigned int u;
858 859
	int __user *sp = argp;
	int s;
860
	int ret;
A
Arnd Bergmann 已提交
861 862 863 864 865 866

	switch (cmd) {
	case TUNSETIFF:
		/* ignore the name, just look at flags */
		if (get_user(u, &ifr->ifr_flags))
			return -EFAULT;
867 868 869 870 871 872 873 874

		ret = 0;
		if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
			ret = -EINVAL;
		else
			q->flags = u;

		return ret;
A
Arnd Bergmann 已提交
875 876

	case TUNGETIFF:
877
		rcu_read_lock_bh();
878
		vlan = rcu_dereference_bh(q->vlan);
879 880 881 882 883
		if (vlan)
			dev_hold(vlan->dev);
		rcu_read_unlock_bh();

		if (!vlan)
A
Arnd Bergmann 已提交
884 885
			return -ENOLINK;

886
		ret = 0;
887
		if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
888
		    put_user(q->flags, &ifr->ifr_flags))
889 890 891
			ret = -EFAULT;
		dev_put(vlan->dev);
		return ret;
A
Arnd Bergmann 已提交
892 893

	case TUNGETFEATURES:
894
		if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
A
Arnd Bergmann 已提交
895 896 897 898 899 900 901 902 903 904
			return -EFAULT;
		return 0;

	case TUNSETSNDBUF:
		if (get_user(u, up))
			return -EFAULT;

		q->sk.sk_sndbuf = u;
		return 0;

905 906 907 908 909 910 911 912 913 914 915 916 917 918 919
	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;

A
Arnd Bergmann 已提交
920 921 922
	case TUNSETOFFLOAD:
		/* let the user check for future flags */
		if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
923
			    TUN_F_TSO_ECN | TUN_F_UFO))
A
Arnd Bergmann 已提交
924 925
			return -EINVAL;

926 927 928 929
		/* TODO: only accept frames with the features that
			 got enabled for forwarded frames */
		if (!(q->flags & IFF_VNET_HDR))
			return  -EINVAL;
A
Arnd Bergmann 已提交
930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958
		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
};

A
Arnd Bergmann 已提交
959 960 961 962
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);
963
	return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen,
A
Arnd Bergmann 已提交
964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005
			    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);

1006 1007 1008 1009
static int macvtap_device_event(struct notifier_block *unused,
				unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
1010
	struct macvlan_dev *vlan;
1011 1012
	struct device *classdev;
	dev_t devt;
1013
	int err;
1014 1015 1016 1017

	if (dev->rtnl_link_ops != &macvtap_link_ops)
		return NOTIFY_DONE;

1018
	vlan = netdev_priv(dev);
1019 1020 1021 1022 1023 1024 1025

	switch (event) {
	case NETDEV_REGISTER:
		/* Create the device node here after the network device has
		 * been registered but before register_netdevice has
		 * finished running.
		 */
1026 1027 1028 1029 1030
		err = macvtap_get_minor(vlan);
		if (err)
			return notifier_from_errno(err);

		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1031 1032
		classdev = device_create(macvtap_class, &dev->dev, devt,
					 dev, "tap%d", dev->ifindex);
1033 1034
		if (IS_ERR(classdev)) {
			macvtap_free_minor(vlan);
1035
			return notifier_from_errno(PTR_ERR(classdev));
1036
		}
1037 1038
		break;
	case NETDEV_UNREGISTER:
1039
		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1040
		device_destroy(macvtap_class, devt);
1041
		macvtap_free_minor(vlan);
1042 1043 1044 1045 1046 1047 1048 1049 1050 1051
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block macvtap_notifier_block __read_mostly = {
	.notifier_call	= macvtap_device_event,
};

A
Arnd Bergmann 已提交
1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071
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;
	}

1072
	err = register_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1073 1074 1075
	if (err)
		goto out4;

1076 1077 1078 1079
	err = macvlan_link_register(&macvtap_link_ops);
	if (err)
		goto out5;

A
Arnd Bergmann 已提交
1080 1081
	return 0;

1082 1083
out5:
	unregister_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
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);
1098
	unregister_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1099 1100 1101 1102 1103 1104 1105 1106 1107
	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");