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Merge tag 'devicetree-for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/robh...
[deliverable/linux.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/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_ALL_CSUM) &&
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(SOCK_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(SOCK_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 linear = copylen;
764 i = *from;
765 iov_iter_advance(&i, copylen);
766 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
767 zerocopy = true;
768 }
769
770 if (!zerocopy) {
771 copylen = len;
772 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear)
773 linear = good_linear;
774 else
775 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
776 }
777
778 skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
779 linear, noblock, &err);
780 if (!skb)
781 goto err;
782
783 if (zerocopy)
784 err = zerocopy_sg_from_iter(skb, from);
785 else {
786 err = skb_copy_datagram_from_iter(skb, 0, from, len);
787 if (!err && m && m->msg_control) {
788 struct ubuf_info *uarg = m->msg_control;
789 uarg->callback(uarg, false);
790 }
791 }
792
793 if (err)
794 goto err_kfree;
795
796 skb_set_network_header(skb, ETH_HLEN);
797 skb_reset_mac_header(skb);
798 skb->protocol = eth_hdr(skb)->h_proto;
799
800 if (vnet_hdr_len) {
801 err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr);
802 if (err)
803 goto err_kfree;
804 }
805
806 skb_probe_transport_header(skb, ETH_HLEN);
807
808 /* Move network header to the right position for VLAN tagged packets */
809 if ((skb->protocol == htons(ETH_P_8021Q) ||
810 skb->protocol == htons(ETH_P_8021AD)) &&
811 __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
812 skb_set_network_header(skb, depth);
813
814 rcu_read_lock();
815 vlan = rcu_dereference(q->vlan);
816 /* copy skb_ubuf_info for callback when skb has no error */
817 if (zerocopy) {
818 skb_shinfo(skb)->destructor_arg = m->msg_control;
819 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
820 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
821 }
822 if (vlan) {
823 skb->dev = vlan->dev;
824 dev_queue_xmit(skb);
825 } else {
826 kfree_skb(skb);
827 }
828 rcu_read_unlock();
829
830 return total_len;
831
832 err_kfree:
833 kfree_skb(skb);
834
835 err:
836 rcu_read_lock();
837 vlan = rcu_dereference(q->vlan);
838 if (vlan)
839 this_cpu_inc(vlan->pcpu_stats->tx_dropped);
840 rcu_read_unlock();
841
842 return err;
843 }
844
845 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
846 {
847 struct file *file = iocb->ki_filp;
848 struct macvtap_queue *q = file->private_data;
849
850 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
851 }
852
853 /* Put packet to the user space buffer */
854 static ssize_t macvtap_put_user(struct macvtap_queue *q,
855 const struct sk_buff *skb,
856 struct iov_iter *iter)
857 {
858 int ret;
859 int vnet_hdr_len = 0;
860 int vlan_offset = 0;
861 int total;
862
863 if (q->flags & IFF_VNET_HDR) {
864 struct virtio_net_hdr vnet_hdr;
865 vnet_hdr_len = q->vnet_hdr_sz;
866 if (iov_iter_count(iter) < vnet_hdr_len)
867 return -EINVAL;
868
869 macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr);
870
871 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
872 sizeof(vnet_hdr))
873 return -EFAULT;
874
875 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
876 }
877 total = vnet_hdr_len;
878 total += skb->len;
879
880 if (skb_vlan_tag_present(skb)) {
881 struct {
882 __be16 h_vlan_proto;
883 __be16 h_vlan_TCI;
884 } veth;
885 veth.h_vlan_proto = skb->vlan_proto;
886 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
887
888 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
889 total += VLAN_HLEN;
890
891 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
892 if (ret || !iov_iter_count(iter))
893 goto done;
894
895 ret = copy_to_iter(&veth, sizeof(veth), iter);
896 if (ret != sizeof(veth) || !iov_iter_count(iter))
897 goto done;
898 }
899
900 ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
901 skb->len - vlan_offset);
902
903 done:
904 return ret ? ret : total;
905 }
906
907 static ssize_t macvtap_do_read(struct macvtap_queue *q,
908 struct iov_iter *to,
909 int noblock)
910 {
911 DEFINE_WAIT(wait);
912 struct sk_buff *skb;
913 ssize_t ret = 0;
914
915 if (!iov_iter_count(to))
916 return 0;
917
918 while (1) {
919 if (!noblock)
920 prepare_to_wait(sk_sleep(&q->sk), &wait,
921 TASK_INTERRUPTIBLE);
922
923 /* Read frames from the queue */
924 skb = skb_dequeue(&q->sk.sk_receive_queue);
925 if (skb)
926 break;
927 if (noblock) {
928 ret = -EAGAIN;
929 break;
930 }
931 if (signal_pending(current)) {
932 ret = -ERESTARTSYS;
933 break;
934 }
935 /* Nothing to read, let's sleep */
936 schedule();
937 }
938 if (skb) {
939 ret = macvtap_put_user(q, skb, to);
940 if (unlikely(ret < 0))
941 kfree_skb(skb);
942 else
943 consume_skb(skb);
944 }
945 if (!noblock)
946 finish_wait(sk_sleep(&q->sk), &wait);
947 return ret;
948 }
949
950 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
951 {
952 struct file *file = iocb->ki_filp;
953 struct macvtap_queue *q = file->private_data;
954 ssize_t len = iov_iter_count(to), ret;
955
956 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
957 ret = min_t(ssize_t, ret, len);
958 if (ret > 0)
959 iocb->ki_pos = ret;
960 return ret;
961 }
962
963 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
964 {
965 struct macvlan_dev *vlan;
966
967 ASSERT_RTNL();
968 vlan = rtnl_dereference(q->vlan);
969 if (vlan)
970 dev_hold(vlan->dev);
971
972 return vlan;
973 }
974
975 static void macvtap_put_vlan(struct macvlan_dev *vlan)
976 {
977 dev_put(vlan->dev);
978 }
979
980 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
981 {
982 struct macvtap_queue *q = file->private_data;
983 struct macvlan_dev *vlan;
984 int ret;
985
986 vlan = macvtap_get_vlan(q);
987 if (!vlan)
988 return -EINVAL;
989
990 if (flags & IFF_ATTACH_QUEUE)
991 ret = macvtap_enable_queue(vlan->dev, file, q);
992 else if (flags & IFF_DETACH_QUEUE)
993 ret = macvtap_disable_queue(q);
994 else
995 ret = -EINVAL;
996
997 macvtap_put_vlan(vlan);
998 return ret;
999 }
1000
1001 static int set_offload(struct macvtap_queue *q, unsigned long arg)
1002 {
1003 struct macvlan_dev *vlan;
1004 netdev_features_t features;
1005 netdev_features_t feature_mask = 0;
1006
1007 vlan = rtnl_dereference(q->vlan);
1008 if (!vlan)
1009 return -ENOLINK;
1010
1011 features = vlan->dev->features;
1012
1013 if (arg & TUN_F_CSUM) {
1014 feature_mask = NETIF_F_HW_CSUM;
1015
1016 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
1017 if (arg & TUN_F_TSO_ECN)
1018 feature_mask |= NETIF_F_TSO_ECN;
1019 if (arg & TUN_F_TSO4)
1020 feature_mask |= NETIF_F_TSO;
1021 if (arg & TUN_F_TSO6)
1022 feature_mask |= NETIF_F_TSO6;
1023 }
1024
1025 if (arg & TUN_F_UFO)
1026 feature_mask |= NETIF_F_UFO;
1027 }
1028
1029 /* tun/tap driver inverts the usage for TSO offloads, where
1030 * setting the TSO bit means that the userspace wants to
1031 * accept TSO frames and turning it off means that user space
1032 * does not support TSO.
1033 * For macvtap, we have to invert it to mean the same thing.
1034 * When user space turns off TSO, we turn off GSO/LRO so that
1035 * user-space will not receive TSO frames.
1036 */
1037 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
1038 features |= RX_OFFLOADS;
1039 else
1040 features &= ~RX_OFFLOADS;
1041
1042 /* tap_features are the same as features on tun/tap and
1043 * reflect user expectations.
1044 */
1045 vlan->tap_features = feature_mask;
1046 vlan->set_features = features;
1047 netdev_update_features(vlan->dev);
1048
1049 return 0;
1050 }
1051
1052 /*
1053 * provide compatibility with generic tun/tap interface
1054 */
1055 static long macvtap_ioctl(struct file *file, unsigned int cmd,
1056 unsigned long arg)
1057 {
1058 struct macvtap_queue *q = file->private_data;
1059 struct macvlan_dev *vlan;
1060 void __user *argp = (void __user *)arg;
1061 struct ifreq __user *ifr = argp;
1062 unsigned int __user *up = argp;
1063 unsigned short u;
1064 int __user *sp = argp;
1065 struct sockaddr sa;
1066 int s;
1067 int ret;
1068
1069 switch (cmd) {
1070 case TUNSETIFF:
1071 /* ignore the name, just look at flags */
1072 if (get_user(u, &ifr->ifr_flags))
1073 return -EFAULT;
1074
1075 ret = 0;
1076 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
1077 ret = -EINVAL;
1078 else
1079 q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
1080
1081 return ret;
1082
1083 case TUNGETIFF:
1084 rtnl_lock();
1085 vlan = macvtap_get_vlan(q);
1086 if (!vlan) {
1087 rtnl_unlock();
1088 return -ENOLINK;
1089 }
1090
1091 ret = 0;
1092 u = q->flags;
1093 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1094 put_user(u, &ifr->ifr_flags))
1095 ret = -EFAULT;
1096 macvtap_put_vlan(vlan);
1097 rtnl_unlock();
1098 return ret;
1099
1100 case TUNSETQUEUE:
1101 if (get_user(u, &ifr->ifr_flags))
1102 return -EFAULT;
1103 rtnl_lock();
1104 ret = macvtap_ioctl_set_queue(file, u);
1105 rtnl_unlock();
1106 return ret;
1107
1108 case TUNGETFEATURES:
1109 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
1110 return -EFAULT;
1111 return 0;
1112
1113 case TUNSETSNDBUF:
1114 if (get_user(s, sp))
1115 return -EFAULT;
1116
1117 q->sk.sk_sndbuf = s;
1118 return 0;
1119
1120 case TUNGETVNETHDRSZ:
1121 s = q->vnet_hdr_sz;
1122 if (put_user(s, sp))
1123 return -EFAULT;
1124 return 0;
1125
1126 case TUNSETVNETHDRSZ:
1127 if (get_user(s, sp))
1128 return -EFAULT;
1129 if (s < (int)sizeof(struct virtio_net_hdr))
1130 return -EINVAL;
1131
1132 q->vnet_hdr_sz = s;
1133 return 0;
1134
1135 case TUNGETVNETLE:
1136 s = !!(q->flags & MACVTAP_VNET_LE);
1137 if (put_user(s, sp))
1138 return -EFAULT;
1139 return 0;
1140
1141 case TUNSETVNETLE:
1142 if (get_user(s, sp))
1143 return -EFAULT;
1144 if (s)
1145 q->flags |= MACVTAP_VNET_LE;
1146 else
1147 q->flags &= ~MACVTAP_VNET_LE;
1148 return 0;
1149
1150 case TUNGETVNETBE:
1151 return macvtap_get_vnet_be(q, sp);
1152
1153 case TUNSETVNETBE:
1154 return macvtap_set_vnet_be(q, sp);
1155
1156 case TUNSETOFFLOAD:
1157 /* let the user check for future flags */
1158 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
1159 TUN_F_TSO_ECN | TUN_F_UFO))
1160 return -EINVAL;
1161
1162 rtnl_lock();
1163 ret = set_offload(q, arg);
1164 rtnl_unlock();
1165 return ret;
1166
1167 case SIOCGIFHWADDR:
1168 rtnl_lock();
1169 vlan = macvtap_get_vlan(q);
1170 if (!vlan) {
1171 rtnl_unlock();
1172 return -ENOLINK;
1173 }
1174 ret = 0;
1175 u = vlan->dev->type;
1176 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1177 copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
1178 put_user(u, &ifr->ifr_hwaddr.sa_family))
1179 ret = -EFAULT;
1180 macvtap_put_vlan(vlan);
1181 rtnl_unlock();
1182 return ret;
1183
1184 case SIOCSIFHWADDR:
1185 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
1186 return -EFAULT;
1187 rtnl_lock();
1188 vlan = macvtap_get_vlan(q);
1189 if (!vlan) {
1190 rtnl_unlock();
1191 return -ENOLINK;
1192 }
1193 ret = dev_set_mac_address(vlan->dev, &sa);
1194 macvtap_put_vlan(vlan);
1195 rtnl_unlock();
1196 return ret;
1197
1198 default:
1199 return -EINVAL;
1200 }
1201 }
1202
1203 #ifdef CONFIG_COMPAT
1204 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
1205 unsigned long arg)
1206 {
1207 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1208 }
1209 #endif
1210
1211 static const struct file_operations macvtap_fops = {
1212 .owner = THIS_MODULE,
1213 .open = macvtap_open,
1214 .release = macvtap_release,
1215 .read_iter = macvtap_read_iter,
1216 .write_iter = macvtap_write_iter,
1217 .poll = macvtap_poll,
1218 .llseek = no_llseek,
1219 .unlocked_ioctl = macvtap_ioctl,
1220 #ifdef CONFIG_COMPAT
1221 .compat_ioctl = macvtap_compat_ioctl,
1222 #endif
1223 };
1224
1225 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
1226 size_t total_len)
1227 {
1228 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1229 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
1230 }
1231
1232 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
1233 size_t total_len, int flags)
1234 {
1235 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1236 int ret;
1237 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1238 return -EINVAL;
1239 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
1240 if (ret > total_len) {
1241 m->msg_flags |= MSG_TRUNC;
1242 ret = flags & MSG_TRUNC ? ret : total_len;
1243 }
1244 return ret;
1245 }
1246
1247 /* Ops structure to mimic raw sockets with tun */
1248 static const struct proto_ops macvtap_socket_ops = {
1249 .sendmsg = macvtap_sendmsg,
1250 .recvmsg = macvtap_recvmsg,
1251 };
1252
1253 /* Get an underlying socket object from tun file. Returns error unless file is
1254 * attached to a device. The returned object works like a packet socket, it
1255 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1256 * holding a reference to the file for as long as the socket is in use. */
1257 struct socket *macvtap_get_socket(struct file *file)
1258 {
1259 struct macvtap_queue *q;
1260 if (file->f_op != &macvtap_fops)
1261 return ERR_PTR(-EINVAL);
1262 q = file->private_data;
1263 if (!q)
1264 return ERR_PTR(-EBADFD);
1265 return &q->sock;
1266 }
1267 EXPORT_SYMBOL_GPL(macvtap_get_socket);
1268
1269 static int macvtap_device_event(struct notifier_block *unused,
1270 unsigned long event, void *ptr)
1271 {
1272 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1273 struct macvlan_dev *vlan;
1274 struct device *classdev;
1275 dev_t devt;
1276 int err;
1277
1278 if (dev->rtnl_link_ops != &macvtap_link_ops)
1279 return NOTIFY_DONE;
1280
1281 vlan = netdev_priv(dev);
1282
1283 switch (event) {
1284 case NETDEV_REGISTER:
1285 /* Create the device node here after the network device has
1286 * been registered but before register_netdevice has
1287 * finished running.
1288 */
1289 err = macvtap_get_minor(vlan);
1290 if (err)
1291 return notifier_from_errno(err);
1292
1293 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1294 classdev = device_create(macvtap_class, &dev->dev, devt,
1295 dev, "tap%d", dev->ifindex);
1296 if (IS_ERR(classdev)) {
1297 macvtap_free_minor(vlan);
1298 return notifier_from_errno(PTR_ERR(classdev));
1299 }
1300 break;
1301 case NETDEV_UNREGISTER:
1302 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1303 device_destroy(macvtap_class, devt);
1304 macvtap_free_minor(vlan);
1305 break;
1306 }
1307
1308 return NOTIFY_DONE;
1309 }
1310
1311 static struct notifier_block macvtap_notifier_block __read_mostly = {
1312 .notifier_call = macvtap_device_event,
1313 };
1314
1315 static int macvtap_init(void)
1316 {
1317 int err;
1318
1319 err = alloc_chrdev_region(&macvtap_major, 0,
1320 MACVTAP_NUM_DEVS, "macvtap");
1321 if (err)
1322 goto out1;
1323
1324 cdev_init(&macvtap_cdev, &macvtap_fops);
1325 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1326 if (err)
1327 goto out2;
1328
1329 macvtap_class = class_create(THIS_MODULE, "macvtap");
1330 if (IS_ERR(macvtap_class)) {
1331 err = PTR_ERR(macvtap_class);
1332 goto out3;
1333 }
1334
1335 err = register_netdevice_notifier(&macvtap_notifier_block);
1336 if (err)
1337 goto out4;
1338
1339 err = macvlan_link_register(&macvtap_link_ops);
1340 if (err)
1341 goto out5;
1342
1343 return 0;
1344
1345 out5:
1346 unregister_netdevice_notifier(&macvtap_notifier_block);
1347 out4:
1348 class_unregister(macvtap_class);
1349 out3:
1350 cdev_del(&macvtap_cdev);
1351 out2:
1352 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1353 out1:
1354 return err;
1355 }
1356 module_init(macvtap_init);
1357
1358 static void macvtap_exit(void)
1359 {
1360 rtnl_link_unregister(&macvtap_link_ops);
1361 unregister_netdevice_notifier(&macvtap_notifier_block);
1362 class_unregister(macvtap_class);
1363 cdev_del(&macvtap_cdev);
1364 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1365 idr_destroy(&minor_idr);
1366 }
1367 module_exit(macvtap_exit);
1368
1369 MODULE_ALIAS_RTNL_LINK("macvtap");
1370 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1371 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
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