xref: /openbmc/linux/drivers/net/macvtap.c (revision 92a76f6d)
1 #include <linux/etherdevice.h>
2 #include <linux/if_macvlan.h>
3 #include <linux/if_vlan.h>
4 #include <linux/interrupt.h>
5 #include <linux/nsproxy.h>
6 #include <linux/compat.h>
7 #include <linux/if_tun.h>
8 #include <linux/module.h>
9 #include <linux/skbuff.h>
10 #include <linux/cache.h>
11 #include <linux/sched.h>
12 #include <linux/types.h>
13 #include <linux/slab.h>
14 #include <linux/wait.h>
15 #include <linux/cdev.h>
16 #include <linux/idr.h>
17 #include <linux/fs.h>
18 #include <linux/uio.h>
19 
20 #include <net/net_namespace.h>
21 #include <net/rtnetlink.h>
22 #include <net/sock.h>
23 #include <linux/virtio_net.h>
24 
25 /*
26  * A macvtap queue is the central object of this driver, it connects
27  * an open character device to a macvlan interface. There can be
28  * multiple queues on one interface, which map back to queues
29  * implemented in hardware on the underlying device.
30  *
31  * macvtap_proto is used to allocate queues through the sock allocation
32  * mechanism.
33  *
34  */
35 struct macvtap_queue {
36 	struct sock sk;
37 	struct socket sock;
38 	struct socket_wq wq;
39 	int vnet_hdr_sz;
40 	struct macvlan_dev __rcu *vlan;
41 	struct file *file;
42 	unsigned int flags;
43 	u16 queue_index;
44 	bool enabled;
45 	struct list_head next;
46 };
47 
48 #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
49 
50 #define MACVTAP_VNET_LE 0x80000000
51 #define MACVTAP_VNET_BE 0x40000000
52 
53 #ifdef CONFIG_TUN_VNET_CROSS_LE
54 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
55 {
56 	return q->flags & MACVTAP_VNET_BE ? false :
57 		virtio_legacy_is_little_endian();
58 }
59 
60 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp)
61 {
62 	int s = !!(q->flags & MACVTAP_VNET_BE);
63 
64 	if (put_user(s, sp))
65 		return -EFAULT;
66 
67 	return 0;
68 }
69 
70 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp)
71 {
72 	int s;
73 
74 	if (get_user(s, sp))
75 		return -EFAULT;
76 
77 	if (s)
78 		q->flags |= MACVTAP_VNET_BE;
79 	else
80 		q->flags &= ~MACVTAP_VNET_BE;
81 
82 	return 0;
83 }
84 #else
85 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
86 {
87 	return virtio_legacy_is_little_endian();
88 }
89 
90 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp)
91 {
92 	return -EINVAL;
93 }
94 
95 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp)
96 {
97 	return -EINVAL;
98 }
99 #endif /* CONFIG_TUN_VNET_CROSS_LE */
100 
101 static inline bool macvtap_is_little_endian(struct macvtap_queue *q)
102 {
103 	return q->flags & MACVTAP_VNET_LE ||
104 		macvtap_legacy_is_little_endian(q);
105 }
106 
107 static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
108 {
109 	return __virtio16_to_cpu(macvtap_is_little_endian(q), val);
110 }
111 
112 static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
113 {
114 	return __cpu_to_virtio16(macvtap_is_little_endian(q), val);
115 }
116 
117 static struct proto macvtap_proto = {
118 	.name = "macvtap",
119 	.owner = THIS_MODULE,
120 	.obj_size = sizeof (struct macvtap_queue),
121 };
122 
123 /*
124  * Variables for dealing with macvtaps device numbers.
125  */
126 static dev_t macvtap_major;
127 #define MACVTAP_NUM_DEVS (1U << MINORBITS)
128 static DEFINE_MUTEX(minor_lock);
129 static DEFINE_IDR(minor_idr);
130 
131 #define GOODCOPY_LEN 128
132 static struct class *macvtap_class;
133 static struct cdev macvtap_cdev;
134 
135 static const struct proto_ops macvtap_socket_ops;
136 
137 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
138 		      NETIF_F_TSO6 | NETIF_F_UFO)
139 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
140 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
141 
142 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev)
143 {
144 	return rcu_dereference(dev->rx_handler_data);
145 }
146 
147 /*
148  * RCU usage:
149  * The macvtap_queue and the macvlan_dev are loosely coupled, the
150  * pointers from one to the other can only be read while rcu_read_lock
151  * or rtnl is held.
152  *
153  * Both the file and the macvlan_dev hold a reference on the macvtap_queue
154  * through sock_hold(&q->sk). When the macvlan_dev goes away first,
155  * q->vlan becomes inaccessible. When the files gets closed,
156  * macvtap_get_queue() fails.
157  *
158  * There may still be references to the struct sock inside of the
159  * queue from outbound SKBs, but these never reference back to the
160  * file or the dev. The data structure is freed through __sk_free
161  * when both our references and any pending SKBs are gone.
162  */
163 
164 static int macvtap_enable_queue(struct net_device *dev, struct file *file,
165 				struct macvtap_queue *q)
166 {
167 	struct macvlan_dev *vlan = netdev_priv(dev);
168 	int err = -EINVAL;
169 
170 	ASSERT_RTNL();
171 
172 	if (q->enabled)
173 		goto out;
174 
175 	err = 0;
176 	rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
177 	q->queue_index = vlan->numvtaps;
178 	q->enabled = true;
179 
180 	vlan->numvtaps++;
181 out:
182 	return err;
183 }
184 
185 /* Requires RTNL */
186 static int macvtap_set_queue(struct net_device *dev, struct file *file,
187 			     struct macvtap_queue *q)
188 {
189 	struct macvlan_dev *vlan = netdev_priv(dev);
190 
191 	if (vlan->numqueues == MAX_MACVTAP_QUEUES)
192 		return -EBUSY;
193 
194 	rcu_assign_pointer(q->vlan, vlan);
195 	rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
196 	sock_hold(&q->sk);
197 
198 	q->file = file;
199 	q->queue_index = vlan->numvtaps;
200 	q->enabled = true;
201 	file->private_data = q;
202 	list_add_tail(&q->next, &vlan->queue_list);
203 
204 	vlan->numvtaps++;
205 	vlan->numqueues++;
206 
207 	return 0;
208 }
209 
210 static int macvtap_disable_queue(struct macvtap_queue *q)
211 {
212 	struct macvlan_dev *vlan;
213 	struct macvtap_queue *nq;
214 
215 	ASSERT_RTNL();
216 	if (!q->enabled)
217 		return -EINVAL;
218 
219 	vlan = rtnl_dereference(q->vlan);
220 
221 	if (vlan) {
222 		int index = q->queue_index;
223 		BUG_ON(index >= vlan->numvtaps);
224 		nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]);
225 		nq->queue_index = index;
226 
227 		rcu_assign_pointer(vlan->taps[index], nq);
228 		RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);
229 		q->enabled = false;
230 
231 		vlan->numvtaps--;
232 	}
233 
234 	return 0;
235 }
236 
237 /*
238  * The file owning the queue got closed, give up both
239  * the reference that the files holds as well as the
240  * one from the macvlan_dev if that still exists.
241  *
242  * Using the spinlock makes sure that we don't get
243  * to the queue again after destroying it.
244  */
245 static void macvtap_put_queue(struct macvtap_queue *q)
246 {
247 	struct macvlan_dev *vlan;
248 
249 	rtnl_lock();
250 	vlan = rtnl_dereference(q->vlan);
251 
252 	if (vlan) {
253 		if (q->enabled)
254 			BUG_ON(macvtap_disable_queue(q));
255 
256 		vlan->numqueues--;
257 		RCU_INIT_POINTER(q->vlan, NULL);
258 		sock_put(&q->sk);
259 		list_del_init(&q->next);
260 	}
261 
262 	rtnl_unlock();
263 
264 	synchronize_rcu();
265 	sock_put(&q->sk);
266 }
267 
268 /*
269  * Select a queue based on the rxq of the device on which this packet
270  * arrived. If the incoming device is not mq, calculate a flow hash
271  * to select a queue. If all fails, find the first available queue.
272  * Cache vlan->numvtaps since it can become zero during the execution
273  * of this function.
274  */
275 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
276 					       struct sk_buff *skb)
277 {
278 	struct macvlan_dev *vlan = netdev_priv(dev);
279 	struct macvtap_queue *tap = NULL;
280 	/* Access to taps array is protected by rcu, but access to numvtaps
281 	 * isn't. Below we use it to lookup a queue, but treat it as a hint
282 	 * and validate that the result isn't NULL - in case we are
283 	 * racing against queue removal.
284 	 */
285 	int numvtaps = ACCESS_ONCE(vlan->numvtaps);
286 	__u32 rxq;
287 
288 	if (!numvtaps)
289 		goto out;
290 
291 	/* Check if we can use flow to select a queue */
292 	rxq = skb_get_hash(skb);
293 	if (rxq) {
294 		tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
295 		goto out;
296 	}
297 
298 	if (likely(skb_rx_queue_recorded(skb))) {
299 		rxq = skb_get_rx_queue(skb);
300 
301 		while (unlikely(rxq >= numvtaps))
302 			rxq -= numvtaps;
303 
304 		tap = rcu_dereference(vlan->taps[rxq]);
305 		goto out;
306 	}
307 
308 	tap = rcu_dereference(vlan->taps[0]);
309 out:
310 	return tap;
311 }
312 
313 /*
314  * The net_device is going away, give up the reference
315  * that it holds on all queues and safely set the pointer
316  * from the queues to NULL.
317  */
318 static void macvtap_del_queues(struct net_device *dev)
319 {
320 	struct macvlan_dev *vlan = netdev_priv(dev);
321 	struct macvtap_queue *q, *tmp;
322 
323 	ASSERT_RTNL();
324 	list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {
325 		list_del_init(&q->next);
326 		RCU_INIT_POINTER(q->vlan, NULL);
327 		if (q->enabled)
328 			vlan->numvtaps--;
329 		vlan->numqueues--;
330 		sock_put(&q->sk);
331 	}
332 	BUG_ON(vlan->numvtaps);
333 	BUG_ON(vlan->numqueues);
334 	/* guarantee that any future macvtap_set_queue will fail */
335 	vlan->numvtaps = MAX_MACVTAP_QUEUES;
336 }
337 
338 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
339 {
340 	struct sk_buff *skb = *pskb;
341 	struct net_device *dev = skb->dev;
342 	struct macvlan_dev *vlan;
343 	struct macvtap_queue *q;
344 	netdev_features_t features = TAP_FEATURES;
345 
346 	vlan = macvtap_get_vlan_rcu(dev);
347 	if (!vlan)
348 		return RX_HANDLER_PASS;
349 
350 	q = macvtap_get_queue(dev, skb);
351 	if (!q)
352 		return RX_HANDLER_PASS;
353 
354 	if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
355 		goto drop;
356 
357 	skb_push(skb, ETH_HLEN);
358 
359 	/* Apply the forward feature mask so that we perform segmentation
360 	 * according to users wishes.  This only works if VNET_HDR is
361 	 * enabled.
362 	 */
363 	if (q->flags & IFF_VNET_HDR)
364 		features |= vlan->tap_features;
365 	if (netif_needs_gso(skb, features)) {
366 		struct sk_buff *segs = __skb_gso_segment(skb, features, false);
367 
368 		if (IS_ERR(segs))
369 			goto drop;
370 
371 		if (!segs) {
372 			skb_queue_tail(&q->sk.sk_receive_queue, skb);
373 			goto wake_up;
374 		}
375 
376 		kfree_skb(skb);
377 		while (segs) {
378 			struct sk_buff *nskb = segs->next;
379 
380 			segs->next = NULL;
381 			skb_queue_tail(&q->sk.sk_receive_queue, segs);
382 			segs = nskb;
383 		}
384 	} else {
385 		/* If we receive a partial checksum and the tap side
386 		 * doesn't support checksum offload, compute the checksum.
387 		 * Note: it doesn't matter which checksum feature to
388 		 *        check, we either support them all or none.
389 		 */
390 		if (skb->ip_summed == CHECKSUM_PARTIAL &&
391 		    !(features & NETIF_F_CSUM_MASK) &&
392 		    skb_checksum_help(skb))
393 			goto drop;
394 		skb_queue_tail(&q->sk.sk_receive_queue, skb);
395 	}
396 
397 wake_up:
398 	wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
399 	return RX_HANDLER_CONSUMED;
400 
401 drop:
402 	/* Count errors/drops only here, thus don't care about args. */
403 	macvlan_count_rx(vlan, 0, 0, 0);
404 	kfree_skb(skb);
405 	return RX_HANDLER_CONSUMED;
406 }
407 
408 static int macvtap_get_minor(struct macvlan_dev *vlan)
409 {
410 	int retval = -ENOMEM;
411 
412 	mutex_lock(&minor_lock);
413 	retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL);
414 	if (retval >= 0) {
415 		vlan->minor = retval;
416 	} else if (retval == -ENOSPC) {
417 		printk(KERN_ERR "too many macvtap devices\n");
418 		retval = -EINVAL;
419 	}
420 	mutex_unlock(&minor_lock);
421 	return retval < 0 ? retval : 0;
422 }
423 
424 static void macvtap_free_minor(struct macvlan_dev *vlan)
425 {
426 	mutex_lock(&minor_lock);
427 	if (vlan->minor) {
428 		idr_remove(&minor_idr, vlan->minor);
429 		vlan->minor = 0;
430 	}
431 	mutex_unlock(&minor_lock);
432 }
433 
434 static struct net_device *dev_get_by_macvtap_minor(int minor)
435 {
436 	struct net_device *dev = NULL;
437 	struct macvlan_dev *vlan;
438 
439 	mutex_lock(&minor_lock);
440 	vlan = idr_find(&minor_idr, minor);
441 	if (vlan) {
442 		dev = vlan->dev;
443 		dev_hold(dev);
444 	}
445 	mutex_unlock(&minor_lock);
446 	return dev;
447 }
448 
449 static int macvtap_newlink(struct net *src_net,
450 			   struct net_device *dev,
451 			   struct nlattr *tb[],
452 			   struct nlattr *data[])
453 {
454 	struct macvlan_dev *vlan = netdev_priv(dev);
455 	int err;
456 
457 	INIT_LIST_HEAD(&vlan->queue_list);
458 
459 	/* Since macvlan supports all offloads by default, make
460 	 * tap support all offloads also.
461 	 */
462 	vlan->tap_features = TUN_OFFLOADS;
463 
464 	err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
465 	if (err)
466 		return err;
467 
468 	/* Don't put anything that may fail after macvlan_common_newlink
469 	 * because we can't undo what it does.
470 	 */
471 	return macvlan_common_newlink(src_net, dev, tb, data);
472 }
473 
474 static void macvtap_dellink(struct net_device *dev,
475 			    struct list_head *head)
476 {
477 	netdev_rx_handler_unregister(dev);
478 	macvtap_del_queues(dev);
479 	macvlan_dellink(dev, head);
480 }
481 
482 static void macvtap_setup(struct net_device *dev)
483 {
484 	macvlan_common_setup(dev);
485 	dev->tx_queue_len = TUN_READQ_SIZE;
486 }
487 
488 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
489 	.kind		= "macvtap",
490 	.setup		= macvtap_setup,
491 	.newlink	= macvtap_newlink,
492 	.dellink	= macvtap_dellink,
493 };
494 
495 
496 static void macvtap_sock_write_space(struct sock *sk)
497 {
498 	wait_queue_head_t *wqueue;
499 
500 	if (!sock_writeable(sk) ||
501 	    !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
502 		return;
503 
504 	wqueue = sk_sleep(sk);
505 	if (wqueue && waitqueue_active(wqueue))
506 		wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
507 }
508 
509 static void macvtap_sock_destruct(struct sock *sk)
510 {
511 	skb_queue_purge(&sk->sk_receive_queue);
512 }
513 
514 static int macvtap_open(struct inode *inode, struct file *file)
515 {
516 	struct net *net = current->nsproxy->net_ns;
517 	struct net_device *dev;
518 	struct macvtap_queue *q;
519 	int err = -ENODEV;
520 
521 	rtnl_lock();
522 	dev = dev_get_by_macvtap_minor(iminor(inode));
523 	if (!dev)
524 		goto out;
525 
526 	err = -ENOMEM;
527 	q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
528 					     &macvtap_proto, 0);
529 	if (!q)
530 		goto out;
531 
532 	RCU_INIT_POINTER(q->sock.wq, &q->wq);
533 	init_waitqueue_head(&q->wq.wait);
534 	q->sock.type = SOCK_RAW;
535 	q->sock.state = SS_CONNECTED;
536 	q->sock.file = file;
537 	q->sock.ops = &macvtap_socket_ops;
538 	sock_init_data(&q->sock, &q->sk);
539 	q->sk.sk_write_space = macvtap_sock_write_space;
540 	q->sk.sk_destruct = macvtap_sock_destruct;
541 	q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
542 	q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
543 
544 	/*
545 	 * so far only KVM virtio_net uses macvtap, enable zero copy between
546 	 * guest kernel and host kernel when lower device supports zerocopy
547 	 *
548 	 * The macvlan supports zerocopy iff the lower device supports zero
549 	 * copy so we don't have to look at the lower device directly.
550 	 */
551 	if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
552 		sock_set_flag(&q->sk, SOCK_ZEROCOPY);
553 
554 	err = macvtap_set_queue(dev, file, q);
555 	if (err)
556 		sock_put(&q->sk);
557 
558 out:
559 	if (dev)
560 		dev_put(dev);
561 
562 	rtnl_unlock();
563 	return err;
564 }
565 
566 static int macvtap_release(struct inode *inode, struct file *file)
567 {
568 	struct macvtap_queue *q = file->private_data;
569 	macvtap_put_queue(q);
570 	return 0;
571 }
572 
573 static unsigned int macvtap_poll(struct file *file, poll_table * wait)
574 {
575 	struct macvtap_queue *q = file->private_data;
576 	unsigned int mask = POLLERR;
577 
578 	if (!q)
579 		goto out;
580 
581 	mask = 0;
582 	poll_wait(file, &q->wq.wait, wait);
583 
584 	if (!skb_queue_empty(&q->sk.sk_receive_queue))
585 		mask |= POLLIN | POLLRDNORM;
586 
587 	if (sock_writeable(&q->sk) ||
588 	    (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
589 	     sock_writeable(&q->sk)))
590 		mask |= POLLOUT | POLLWRNORM;
591 
592 out:
593 	return mask;
594 }
595 
596 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
597 						size_t len, size_t linear,
598 						int noblock, int *err)
599 {
600 	struct sk_buff *skb;
601 
602 	/* Under a page?  Don't bother with paged skb. */
603 	if (prepad + len < PAGE_SIZE || !linear)
604 		linear = len;
605 
606 	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
607 				   err, 0);
608 	if (!skb)
609 		return NULL;
610 
611 	skb_reserve(skb, prepad);
612 	skb_put(skb, linear);
613 	skb->data_len = len - linear;
614 	skb->len += len - linear;
615 
616 	return skb;
617 }
618 
619 /*
620  * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
621  * be shared with the tun/tap driver.
622  */
623 static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q,
624 				     struct sk_buff *skb,
625 				     struct virtio_net_hdr *vnet_hdr)
626 {
627 	unsigned short gso_type = 0;
628 	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
629 		switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
630 		case VIRTIO_NET_HDR_GSO_TCPV4:
631 			gso_type = SKB_GSO_TCPV4;
632 			break;
633 		case VIRTIO_NET_HDR_GSO_TCPV6:
634 			gso_type = SKB_GSO_TCPV6;
635 			break;
636 		case VIRTIO_NET_HDR_GSO_UDP:
637 			gso_type = SKB_GSO_UDP;
638 			break;
639 		default:
640 			return -EINVAL;
641 		}
642 
643 		if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
644 			gso_type |= SKB_GSO_TCP_ECN;
645 
646 		if (vnet_hdr->gso_size == 0)
647 			return -EINVAL;
648 	}
649 
650 	if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
651 		if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start),
652 					  macvtap16_to_cpu(q, vnet_hdr->csum_offset)))
653 			return -EINVAL;
654 	}
655 
656 	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
657 		skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size);
658 		skb_shinfo(skb)->gso_type = gso_type;
659 
660 		/* Header must be checked, and gso_segs computed. */
661 		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
662 		skb_shinfo(skb)->gso_segs = 0;
663 	}
664 	return 0;
665 }
666 
667 static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q,
668 				    const struct sk_buff *skb,
669 				    struct virtio_net_hdr *vnet_hdr)
670 {
671 	memset(vnet_hdr, 0, sizeof(*vnet_hdr));
672 
673 	if (skb_is_gso(skb)) {
674 		struct skb_shared_info *sinfo = skb_shinfo(skb);
675 
676 		/* This is a hint as to how much should be linear. */
677 		vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb));
678 		vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size);
679 		if (sinfo->gso_type & SKB_GSO_TCPV4)
680 			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
681 		else if (sinfo->gso_type & SKB_GSO_TCPV6)
682 			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
683 		else if (sinfo->gso_type & SKB_GSO_UDP)
684 			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
685 		else
686 			BUG();
687 		if (sinfo->gso_type & SKB_GSO_TCP_ECN)
688 			vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
689 	} else
690 		vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
691 
692 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
693 		vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
694 		if (skb_vlan_tag_present(skb))
695 			vnet_hdr->csum_start = cpu_to_macvtap16(q,
696 				skb_checksum_start_offset(skb) + VLAN_HLEN);
697 		else
698 			vnet_hdr->csum_start = cpu_to_macvtap16(q,
699 				skb_checksum_start_offset(skb));
700 		vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset);
701 	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
702 		vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
703 	} /* else everything is zero */
704 }
705 
706 /* Neighbour code has some assumptions on HH_DATA_MOD alignment */
707 #define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
708 
709 /* Get packet from user space buffer */
710 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
711 				struct iov_iter *from, int noblock)
712 {
713 	int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
714 	struct sk_buff *skb;
715 	struct macvlan_dev *vlan;
716 	unsigned long total_len = iov_iter_count(from);
717 	unsigned long len = total_len;
718 	int err;
719 	struct virtio_net_hdr vnet_hdr = { 0 };
720 	int vnet_hdr_len = 0;
721 	int copylen = 0;
722 	int depth;
723 	bool zerocopy = false;
724 	size_t linear;
725 	ssize_t n;
726 
727 	if (q->flags & IFF_VNET_HDR) {
728 		vnet_hdr_len = q->vnet_hdr_sz;
729 
730 		err = -EINVAL;
731 		if (len < vnet_hdr_len)
732 			goto err;
733 		len -= vnet_hdr_len;
734 
735 		err = -EFAULT;
736 		n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
737 		if (n != sizeof(vnet_hdr))
738 			goto err;
739 		iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
740 		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
741 		     macvtap16_to_cpu(q, vnet_hdr.csum_start) +
742 		     macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
743 			     macvtap16_to_cpu(q, vnet_hdr.hdr_len))
744 			vnet_hdr.hdr_len = cpu_to_macvtap16(q,
745 				 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
746 				 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
747 		err = -EINVAL;
748 		if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
749 			goto err;
750 	}
751 
752 	err = -EINVAL;
753 	if (unlikely(len < ETH_HLEN))
754 		goto err;
755 
756 	if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
757 		struct iov_iter i;
758 
759 		copylen = vnet_hdr.hdr_len ?
760 			macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
761 		if (copylen > good_linear)
762 			copylen = good_linear;
763 		else if (copylen < ETH_HLEN)
764 			copylen = ETH_HLEN;
765 		linear = copylen;
766 		i = *from;
767 		iov_iter_advance(&i, copylen);
768 		if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
769 			zerocopy = true;
770 	}
771 
772 	if (!zerocopy) {
773 		copylen = len;
774 		linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
775 		if (linear > good_linear)
776 			linear = good_linear;
777 		else if (linear < ETH_HLEN)
778 			linear = ETH_HLEN;
779 	}
780 
781 	skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
782 				linear, noblock, &err);
783 	if (!skb)
784 		goto err;
785 
786 	if (zerocopy)
787 		err = zerocopy_sg_from_iter(skb, from);
788 	else {
789 		err = skb_copy_datagram_from_iter(skb, 0, from, len);
790 		if (!err && m && m->msg_control) {
791 			struct ubuf_info *uarg = m->msg_control;
792 			uarg->callback(uarg, false);
793 		}
794 	}
795 
796 	if (err)
797 		goto err_kfree;
798 
799 	skb_set_network_header(skb, ETH_HLEN);
800 	skb_reset_mac_header(skb);
801 	skb->protocol = eth_hdr(skb)->h_proto;
802 
803 	if (vnet_hdr_len) {
804 		err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr);
805 		if (err)
806 			goto err_kfree;
807 	}
808 
809 	skb_probe_transport_header(skb, ETH_HLEN);
810 
811 	/* Move network header to the right position for VLAN tagged packets */
812 	if ((skb->protocol == htons(ETH_P_8021Q) ||
813 	     skb->protocol == htons(ETH_P_8021AD)) &&
814 	    __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
815 		skb_set_network_header(skb, depth);
816 
817 	rcu_read_lock();
818 	vlan = rcu_dereference(q->vlan);
819 	/* copy skb_ubuf_info for callback when skb has no error */
820 	if (zerocopy) {
821 		skb_shinfo(skb)->destructor_arg = m->msg_control;
822 		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
823 		skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
824 	}
825 	if (vlan) {
826 		skb->dev = vlan->dev;
827 		dev_queue_xmit(skb);
828 	} else {
829 		kfree_skb(skb);
830 	}
831 	rcu_read_unlock();
832 
833 	return total_len;
834 
835 err_kfree:
836 	kfree_skb(skb);
837 
838 err:
839 	rcu_read_lock();
840 	vlan = rcu_dereference(q->vlan);
841 	if (vlan)
842 		this_cpu_inc(vlan->pcpu_stats->tx_dropped);
843 	rcu_read_unlock();
844 
845 	return err;
846 }
847 
848 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
849 {
850 	struct file *file = iocb->ki_filp;
851 	struct macvtap_queue *q = file->private_data;
852 
853 	return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
854 }
855 
856 /* Put packet to the user space buffer */
857 static ssize_t macvtap_put_user(struct macvtap_queue *q,
858 				const struct sk_buff *skb,
859 				struct iov_iter *iter)
860 {
861 	int ret;
862 	int vnet_hdr_len = 0;
863 	int vlan_offset = 0;
864 	int total;
865 
866 	if (q->flags & IFF_VNET_HDR) {
867 		struct virtio_net_hdr vnet_hdr;
868 		vnet_hdr_len = q->vnet_hdr_sz;
869 		if (iov_iter_count(iter) < vnet_hdr_len)
870 			return -EINVAL;
871 
872 		macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr);
873 
874 		if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
875 		    sizeof(vnet_hdr))
876 			return -EFAULT;
877 
878 		iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
879 	}
880 	total = vnet_hdr_len;
881 	total += skb->len;
882 
883 	if (skb_vlan_tag_present(skb)) {
884 		struct {
885 			__be16 h_vlan_proto;
886 			__be16 h_vlan_TCI;
887 		} veth;
888 		veth.h_vlan_proto = skb->vlan_proto;
889 		veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
890 
891 		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
892 		total += VLAN_HLEN;
893 
894 		ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
895 		if (ret || !iov_iter_count(iter))
896 			goto done;
897 
898 		ret = copy_to_iter(&veth, sizeof(veth), iter);
899 		if (ret != sizeof(veth) || !iov_iter_count(iter))
900 			goto done;
901 	}
902 
903 	ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
904 				     skb->len - vlan_offset);
905 
906 done:
907 	return ret ? ret : total;
908 }
909 
910 static ssize_t macvtap_do_read(struct macvtap_queue *q,
911 			       struct iov_iter *to,
912 			       int noblock)
913 {
914 	DEFINE_WAIT(wait);
915 	struct sk_buff *skb;
916 	ssize_t ret = 0;
917 
918 	if (!iov_iter_count(to))
919 		return 0;
920 
921 	while (1) {
922 		if (!noblock)
923 			prepare_to_wait(sk_sleep(&q->sk), &wait,
924 					TASK_INTERRUPTIBLE);
925 
926 		/* Read frames from the queue */
927 		skb = skb_dequeue(&q->sk.sk_receive_queue);
928 		if (skb)
929 			break;
930 		if (noblock) {
931 			ret = -EAGAIN;
932 			break;
933 		}
934 		if (signal_pending(current)) {
935 			ret = -ERESTARTSYS;
936 			break;
937 		}
938 		/* Nothing to read, let's sleep */
939 		schedule();
940 	}
941 	if (!noblock)
942 		finish_wait(sk_sleep(&q->sk), &wait);
943 
944 	if (skb) {
945 		ret = macvtap_put_user(q, skb, to);
946 		if (unlikely(ret < 0))
947 			kfree_skb(skb);
948 		else
949 			consume_skb(skb);
950 	}
951 	return ret;
952 }
953 
954 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
955 {
956 	struct file *file = iocb->ki_filp;
957 	struct macvtap_queue *q = file->private_data;
958 	ssize_t len = iov_iter_count(to), ret;
959 
960 	ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
961 	ret = min_t(ssize_t, ret, len);
962 	if (ret > 0)
963 		iocb->ki_pos = ret;
964 	return ret;
965 }
966 
967 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
968 {
969 	struct macvlan_dev *vlan;
970 
971 	ASSERT_RTNL();
972 	vlan = rtnl_dereference(q->vlan);
973 	if (vlan)
974 		dev_hold(vlan->dev);
975 
976 	return vlan;
977 }
978 
979 static void macvtap_put_vlan(struct macvlan_dev *vlan)
980 {
981 	dev_put(vlan->dev);
982 }
983 
984 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
985 {
986 	struct macvtap_queue *q = file->private_data;
987 	struct macvlan_dev *vlan;
988 	int ret;
989 
990 	vlan = macvtap_get_vlan(q);
991 	if (!vlan)
992 		return -EINVAL;
993 
994 	if (flags & IFF_ATTACH_QUEUE)
995 		ret = macvtap_enable_queue(vlan->dev, file, q);
996 	else if (flags & IFF_DETACH_QUEUE)
997 		ret = macvtap_disable_queue(q);
998 	else
999 		ret = -EINVAL;
1000 
1001 	macvtap_put_vlan(vlan);
1002 	return ret;
1003 }
1004 
1005 static int set_offload(struct macvtap_queue *q, unsigned long arg)
1006 {
1007 	struct macvlan_dev *vlan;
1008 	netdev_features_t features;
1009 	netdev_features_t feature_mask = 0;
1010 
1011 	vlan = rtnl_dereference(q->vlan);
1012 	if (!vlan)
1013 		return -ENOLINK;
1014 
1015 	features = vlan->dev->features;
1016 
1017 	if (arg & TUN_F_CSUM) {
1018 		feature_mask = NETIF_F_HW_CSUM;
1019 
1020 		if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
1021 			if (arg & TUN_F_TSO_ECN)
1022 				feature_mask |= NETIF_F_TSO_ECN;
1023 			if (arg & TUN_F_TSO4)
1024 				feature_mask |= NETIF_F_TSO;
1025 			if (arg & TUN_F_TSO6)
1026 				feature_mask |= NETIF_F_TSO6;
1027 		}
1028 
1029 		if (arg & TUN_F_UFO)
1030 			feature_mask |= NETIF_F_UFO;
1031 	}
1032 
1033 	/* tun/tap driver inverts the usage for TSO offloads, where
1034 	 * setting the TSO bit means that the userspace wants to
1035 	 * accept TSO frames and turning it off means that user space
1036 	 * does not support TSO.
1037 	 * For macvtap, we have to invert it to mean the same thing.
1038 	 * When user space turns off TSO, we turn off GSO/LRO so that
1039 	 * user-space will not receive TSO frames.
1040 	 */
1041 	if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
1042 		features |= RX_OFFLOADS;
1043 	else
1044 		features &= ~RX_OFFLOADS;
1045 
1046 	/* tap_features are the same as features on tun/tap and
1047 	 * reflect user expectations.
1048 	 */
1049 	vlan->tap_features = feature_mask;
1050 	vlan->set_features = features;
1051 	netdev_update_features(vlan->dev);
1052 
1053 	return 0;
1054 }
1055 
1056 /*
1057  * provide compatibility with generic tun/tap interface
1058  */
1059 static long macvtap_ioctl(struct file *file, unsigned int cmd,
1060 			  unsigned long arg)
1061 {
1062 	struct macvtap_queue *q = file->private_data;
1063 	struct macvlan_dev *vlan;
1064 	void __user *argp = (void __user *)arg;
1065 	struct ifreq __user *ifr = argp;
1066 	unsigned int __user *up = argp;
1067 	unsigned short u;
1068 	int __user *sp = argp;
1069 	struct sockaddr sa;
1070 	int s;
1071 	int ret;
1072 
1073 	switch (cmd) {
1074 	case TUNSETIFF:
1075 		/* ignore the name, just look at flags */
1076 		if (get_user(u, &ifr->ifr_flags))
1077 			return -EFAULT;
1078 
1079 		ret = 0;
1080 		if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
1081 			ret = -EINVAL;
1082 		else
1083 			q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
1084 
1085 		return ret;
1086 
1087 	case TUNGETIFF:
1088 		rtnl_lock();
1089 		vlan = macvtap_get_vlan(q);
1090 		if (!vlan) {
1091 			rtnl_unlock();
1092 			return -ENOLINK;
1093 		}
1094 
1095 		ret = 0;
1096 		u = q->flags;
1097 		if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1098 		    put_user(u, &ifr->ifr_flags))
1099 			ret = -EFAULT;
1100 		macvtap_put_vlan(vlan);
1101 		rtnl_unlock();
1102 		return ret;
1103 
1104 	case TUNSETQUEUE:
1105 		if (get_user(u, &ifr->ifr_flags))
1106 			return -EFAULT;
1107 		rtnl_lock();
1108 		ret = macvtap_ioctl_set_queue(file, u);
1109 		rtnl_unlock();
1110 		return ret;
1111 
1112 	case TUNGETFEATURES:
1113 		if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
1114 			return -EFAULT;
1115 		return 0;
1116 
1117 	case TUNSETSNDBUF:
1118 		if (get_user(s, sp))
1119 			return -EFAULT;
1120 
1121 		q->sk.sk_sndbuf = s;
1122 		return 0;
1123 
1124 	case TUNGETVNETHDRSZ:
1125 		s = q->vnet_hdr_sz;
1126 		if (put_user(s, sp))
1127 			return -EFAULT;
1128 		return 0;
1129 
1130 	case TUNSETVNETHDRSZ:
1131 		if (get_user(s, sp))
1132 			return -EFAULT;
1133 		if (s < (int)sizeof(struct virtio_net_hdr))
1134 			return -EINVAL;
1135 
1136 		q->vnet_hdr_sz = s;
1137 		return 0;
1138 
1139 	case TUNGETVNETLE:
1140 		s = !!(q->flags & MACVTAP_VNET_LE);
1141 		if (put_user(s, sp))
1142 			return -EFAULT;
1143 		return 0;
1144 
1145 	case TUNSETVNETLE:
1146 		if (get_user(s, sp))
1147 			return -EFAULT;
1148 		if (s)
1149 			q->flags |= MACVTAP_VNET_LE;
1150 		else
1151 			q->flags &= ~MACVTAP_VNET_LE;
1152 		return 0;
1153 
1154 	case TUNGETVNETBE:
1155 		return macvtap_get_vnet_be(q, sp);
1156 
1157 	case TUNSETVNETBE:
1158 		return macvtap_set_vnet_be(q, sp);
1159 
1160 	case TUNSETOFFLOAD:
1161 		/* let the user check for future flags */
1162 		if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
1163 			    TUN_F_TSO_ECN | TUN_F_UFO))
1164 			return -EINVAL;
1165 
1166 		rtnl_lock();
1167 		ret = set_offload(q, arg);
1168 		rtnl_unlock();
1169 		return ret;
1170 
1171 	case SIOCGIFHWADDR:
1172 		rtnl_lock();
1173 		vlan = macvtap_get_vlan(q);
1174 		if (!vlan) {
1175 			rtnl_unlock();
1176 			return -ENOLINK;
1177 		}
1178 		ret = 0;
1179 		u = vlan->dev->type;
1180 		if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1181 		    copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
1182 		    put_user(u, &ifr->ifr_hwaddr.sa_family))
1183 			ret = -EFAULT;
1184 		macvtap_put_vlan(vlan);
1185 		rtnl_unlock();
1186 		return ret;
1187 
1188 	case SIOCSIFHWADDR:
1189 		if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
1190 			return -EFAULT;
1191 		rtnl_lock();
1192 		vlan = macvtap_get_vlan(q);
1193 		if (!vlan) {
1194 			rtnl_unlock();
1195 			return -ENOLINK;
1196 		}
1197 		ret = dev_set_mac_address(vlan->dev, &sa);
1198 		macvtap_put_vlan(vlan);
1199 		rtnl_unlock();
1200 		return ret;
1201 
1202 	default:
1203 		return -EINVAL;
1204 	}
1205 }
1206 
1207 #ifdef CONFIG_COMPAT
1208 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
1209 				 unsigned long arg)
1210 {
1211 	return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1212 }
1213 #endif
1214 
1215 static const struct file_operations macvtap_fops = {
1216 	.owner		= THIS_MODULE,
1217 	.open		= macvtap_open,
1218 	.release	= macvtap_release,
1219 	.read_iter	= macvtap_read_iter,
1220 	.write_iter	= macvtap_write_iter,
1221 	.poll		= macvtap_poll,
1222 	.llseek		= no_llseek,
1223 	.unlocked_ioctl	= macvtap_ioctl,
1224 #ifdef CONFIG_COMPAT
1225 	.compat_ioctl	= macvtap_compat_ioctl,
1226 #endif
1227 };
1228 
1229 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
1230 			   size_t total_len)
1231 {
1232 	struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1233 	return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
1234 }
1235 
1236 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
1237 			   size_t total_len, int flags)
1238 {
1239 	struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1240 	int ret;
1241 	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1242 		return -EINVAL;
1243 	ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
1244 	if (ret > total_len) {
1245 		m->msg_flags |= MSG_TRUNC;
1246 		ret = flags & MSG_TRUNC ? ret : total_len;
1247 	}
1248 	return ret;
1249 }
1250 
1251 /* Ops structure to mimic raw sockets with tun */
1252 static const struct proto_ops macvtap_socket_ops = {
1253 	.sendmsg = macvtap_sendmsg,
1254 	.recvmsg = macvtap_recvmsg,
1255 };
1256 
1257 /* Get an underlying socket object from tun file.  Returns error unless file is
1258  * attached to a device.  The returned object works like a packet socket, it
1259  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1260  * holding a reference to the file for as long as the socket is in use. */
1261 struct socket *macvtap_get_socket(struct file *file)
1262 {
1263 	struct macvtap_queue *q;
1264 	if (file->f_op != &macvtap_fops)
1265 		return ERR_PTR(-EINVAL);
1266 	q = file->private_data;
1267 	if (!q)
1268 		return ERR_PTR(-EBADFD);
1269 	return &q->sock;
1270 }
1271 EXPORT_SYMBOL_GPL(macvtap_get_socket);
1272 
1273 static int macvtap_device_event(struct notifier_block *unused,
1274 				unsigned long event, void *ptr)
1275 {
1276 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1277 	struct macvlan_dev *vlan;
1278 	struct device *classdev;
1279 	dev_t devt;
1280 	int err;
1281 
1282 	if (dev->rtnl_link_ops != &macvtap_link_ops)
1283 		return NOTIFY_DONE;
1284 
1285 	vlan = netdev_priv(dev);
1286 
1287 	switch (event) {
1288 	case NETDEV_REGISTER:
1289 		/* Create the device node here after the network device has
1290 		 * been registered but before register_netdevice has
1291 		 * finished running.
1292 		 */
1293 		err = macvtap_get_minor(vlan);
1294 		if (err)
1295 			return notifier_from_errno(err);
1296 
1297 		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1298 		classdev = device_create(macvtap_class, &dev->dev, devt,
1299 					 dev, "tap%d", dev->ifindex);
1300 		if (IS_ERR(classdev)) {
1301 			macvtap_free_minor(vlan);
1302 			return notifier_from_errno(PTR_ERR(classdev));
1303 		}
1304 		break;
1305 	case NETDEV_UNREGISTER:
1306 		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1307 		device_destroy(macvtap_class, devt);
1308 		macvtap_free_minor(vlan);
1309 		break;
1310 	}
1311 
1312 	return NOTIFY_DONE;
1313 }
1314 
1315 static struct notifier_block macvtap_notifier_block __read_mostly = {
1316 	.notifier_call	= macvtap_device_event,
1317 };
1318 
1319 static int macvtap_init(void)
1320 {
1321 	int err;
1322 
1323 	err = alloc_chrdev_region(&macvtap_major, 0,
1324 				MACVTAP_NUM_DEVS, "macvtap");
1325 	if (err)
1326 		goto out1;
1327 
1328 	cdev_init(&macvtap_cdev, &macvtap_fops);
1329 	err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1330 	if (err)
1331 		goto out2;
1332 
1333 	macvtap_class = class_create(THIS_MODULE, "macvtap");
1334 	if (IS_ERR(macvtap_class)) {
1335 		err = PTR_ERR(macvtap_class);
1336 		goto out3;
1337 	}
1338 
1339 	err = register_netdevice_notifier(&macvtap_notifier_block);
1340 	if (err)
1341 		goto out4;
1342 
1343 	err = macvlan_link_register(&macvtap_link_ops);
1344 	if (err)
1345 		goto out5;
1346 
1347 	return 0;
1348 
1349 out5:
1350 	unregister_netdevice_notifier(&macvtap_notifier_block);
1351 out4:
1352 	class_unregister(macvtap_class);
1353 out3:
1354 	cdev_del(&macvtap_cdev);
1355 out2:
1356 	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1357 out1:
1358 	return err;
1359 }
1360 module_init(macvtap_init);
1361 
1362 static void macvtap_exit(void)
1363 {
1364 	rtnl_link_unregister(&macvtap_link_ops);
1365 	unregister_netdevice_notifier(&macvtap_notifier_block);
1366 	class_unregister(macvtap_class);
1367 	cdev_del(&macvtap_cdev);
1368 	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1369 	idr_destroy(&minor_idr);
1370 }
1371 module_exit(macvtap_exit);
1372 
1373 MODULE_ALIAS_RTNL_LINK("macvtap");
1374 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1375 MODULE_LICENSE("GPL");
1376