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