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