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perf bench futex: Cache align the worker struct
[linux/fpc-iii.git] / drivers / net / macvtap.c
blob070e3290aa6efea6fcb505cdf0860a4dce676b74
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 #include <linux/skb_array.h>
25
26 /*
27 * A macvtap queue is the central object of this driver, it connects
28 * an open character device to a macvlan interface. There can be
29 * multiple queues on one interface, which map back to queues
30 * implemented in hardware on the underlying device.
31 *
32 * macvtap_proto is used to allocate queues through the sock allocation
33 * mechanism.
34 *
35 */
36 struct macvtap_queue {
37 struct sock sk;
38 struct socket sock;
39 struct socket_wq wq;
40 int vnet_hdr_sz;
41 struct macvlan_dev __rcu *vlan;
42 struct file *file;
43 unsigned int flags;
44 u16 queue_index;
45 bool enabled;
46 struct list_head next;
47 struct skb_array skb_array;
48 };
49
50 #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE)
51
52 #define MACVTAP_VNET_LE 0x80000000
53 #define MACVTAP_VNET_BE 0x40000000
54
55 #ifdef CONFIG_TUN_VNET_CROSS_LE
56 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
57 {
58 return q->flags & MACVTAP_VNET_BE ? false :
59 virtio_legacy_is_little_endian();
60 }
61
62 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp)
63 {
64 int s = !!(q->flags & MACVTAP_VNET_BE);
65
66 if (put_user(s, sp))
67 return -EFAULT;
68
69 return 0;
70 }
71
72 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp)
73 {
74 int s;
75
76 if (get_user(s, sp))
77 return -EFAULT;
78
79 if (s)
80 q->flags |= MACVTAP_VNET_BE;
81 else
82 q->flags &= ~MACVTAP_VNET_BE;
83
84 return 0;
85 }
86 #else
87 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q)
88 {
89 return virtio_legacy_is_little_endian();
90 }
91
92 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp)
93 {
94 return -EINVAL;
95 }
96
97 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp)
98 {
99 return -EINVAL;
100 }
101 #endif /* CONFIG_TUN_VNET_CROSS_LE */
102
103 static inline bool macvtap_is_little_endian(struct macvtap_queue *q)
104 {
105 return q->flags & MACVTAP_VNET_LE ||
106 macvtap_legacy_is_little_endian(q);
107 }
108
109 static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val)
110 {
111 return __virtio16_to_cpu(macvtap_is_little_endian(q), val);
112 }
113
114 static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val)
115 {
116 return __cpu_to_virtio16(macvtap_is_little_endian(q), val);
117 }
118
119 static struct proto macvtap_proto = {
120 .name = "macvtap",
121 .owner = THIS_MODULE,
122 .obj_size = sizeof (struct macvtap_queue),
123 };
124
125 /*
126 * Variables for dealing with macvtaps device numbers.
127 */
128 static dev_t macvtap_major;
129 #define MACVTAP_NUM_DEVS (1U << MINORBITS)
130 static DEFINE_MUTEX(minor_lock);
131 static DEFINE_IDR(minor_idr);
132
133 #define GOODCOPY_LEN 128
134 static const void *macvtap_net_namespace(struct device *d)
135 {
136 struct net_device *dev = to_net_dev(d->parent);
137 return dev_net(dev);
138 }
139
140 static struct class macvtap_class = {
141 .name = "macvtap",
142 .owner = THIS_MODULE,
143 .ns_type = &net_ns_type_operations,
144 .namespace = macvtap_net_namespace,
145 };
146 static struct cdev macvtap_cdev;
147
148 static const struct proto_ops macvtap_socket_ops;
149
150 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
151 NETIF_F_TSO6 | NETIF_F_UFO)
152 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
153 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
154
155 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev)
156 {
157 return rcu_dereference(dev->rx_handler_data);
158 }
159
160 /*
161 * RCU usage:
162 * The macvtap_queue and the macvlan_dev are loosely coupled, the
163 * pointers from one to the other can only be read while rcu_read_lock
164 * or rtnl is held.
165 *
166 * Both the file and the macvlan_dev hold a reference on the macvtap_queue
167 * through sock_hold(&q->sk). When the macvlan_dev goes away first,
168 * q->vlan becomes inaccessible. When the files gets closed,
169 * macvtap_get_queue() fails.
170 *
171 * There may still be references to the struct sock inside of the
172 * queue from outbound SKBs, but these never reference back to the
173 * file or the dev. The data structure is freed through __sk_free
174 * when both our references and any pending SKBs are gone.
175 */
176
177 static int macvtap_enable_queue(struct net_device *dev, struct file *file,
178 struct macvtap_queue *q)
179 {
180 struct macvlan_dev *vlan = netdev_priv(dev);
181 int err = -EINVAL;
182
183 ASSERT_RTNL();
184
185 if (q->enabled)
186 goto out;
187
188 err = 0;
189 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
190 q->queue_index = vlan->numvtaps;
191 q->enabled = true;
192
193 vlan->numvtaps++;
194 out:
195 return err;
196 }
197
198 /* Requires RTNL */
199 static int macvtap_set_queue(struct net_device *dev, struct file *file,
200 struct macvtap_queue *q)
201 {
202 struct macvlan_dev *vlan = netdev_priv(dev);
203
204 if (vlan->numqueues == MAX_MACVTAP_QUEUES)
205 return -EBUSY;
206
207 rcu_assign_pointer(q->vlan, vlan);
208 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q);
209 sock_hold(&q->sk);
210
211 q->file = file;
212 q->queue_index = vlan->numvtaps;
213 q->enabled = true;
214 file->private_data = q;
215 list_add_tail(&q->next, &vlan->queue_list);
216
217 vlan->numvtaps++;
218 vlan->numqueues++;
219
220 return 0;
221 }
222
223 static int macvtap_disable_queue(struct macvtap_queue *q)
224 {
225 struct macvlan_dev *vlan;
226 struct macvtap_queue *nq;
227
228 ASSERT_RTNL();
229 if (!q->enabled)
230 return -EINVAL;
231
232 vlan = rtnl_dereference(q->vlan);
233
234 if (vlan) {
235 int index = q->queue_index;
236 BUG_ON(index >= vlan->numvtaps);
237 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]);
238 nq->queue_index = index;
239
240 rcu_assign_pointer(vlan->taps[index], nq);
241 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL);
242 q->enabled = false;
243
244 vlan->numvtaps--;
245 }
246
247 return 0;
248 }
249
250 /*
251 * The file owning the queue got closed, give up both
252 * the reference that the files holds as well as the
253 * one from the macvlan_dev if that still exists.
254 *
255 * Using the spinlock makes sure that we don't get
256 * to the queue again after destroying it.
257 */
258 static void macvtap_put_queue(struct macvtap_queue *q)
259 {
260 struct macvlan_dev *vlan;
261
262 rtnl_lock();
263 vlan = rtnl_dereference(q->vlan);
264
265 if (vlan) {
266 if (q->enabled)
267 BUG_ON(macvtap_disable_queue(q));
268
269 vlan->numqueues--;
270 RCU_INIT_POINTER(q->vlan, NULL);
271 sock_put(&q->sk);
272 list_del_init(&q->next);
273 }
274
275 rtnl_unlock();
276
277 synchronize_rcu();
278 sock_put(&q->sk);
279 }
280
281 /*
282 * Select a queue based on the rxq of the device on which this packet
283 * arrived. If the incoming device is not mq, calculate a flow hash
284 * to select a queue. If all fails, find the first available queue.
285 * Cache vlan->numvtaps since it can become zero during the execution
286 * of this function.
287 */
288 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
289 struct sk_buff *skb)
290 {
291 struct macvlan_dev *vlan = netdev_priv(dev);
292 struct macvtap_queue *tap = NULL;
293 /* Access to taps array is protected by rcu, but access to numvtaps
294 * isn't. Below we use it to lookup a queue, but treat it as a hint
295 * and validate that the result isn't NULL - in case we are
296 * racing against queue removal.
297 */
298 int numvtaps = ACCESS_ONCE(vlan->numvtaps);
299 __u32 rxq;
300
301 if (!numvtaps)
302 goto out;
303
304 if (numvtaps == 1)
305 goto single;
306
307 /* Check if we can use flow to select a queue */
308 rxq = skb_get_hash(skb);
309 if (rxq) {
310 tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
311 goto out;
312 }
313
314 if (likely(skb_rx_queue_recorded(skb))) {
315 rxq = skb_get_rx_queue(skb);
316
317 while (unlikely(rxq >= numvtaps))
318 rxq -= numvtaps;
319
320 tap = rcu_dereference(vlan->taps[rxq]);
321 goto out;
322 }
323
324 single:
325 tap = rcu_dereference(vlan->taps[0]);
326 out:
327 return tap;
328 }
329
330 /*
331 * The net_device is going away, give up the reference
332 * that it holds on all queues and safely set the pointer
333 * from the queues to NULL.
334 */
335 static void macvtap_del_queues(struct net_device *dev)
336 {
337 struct macvlan_dev *vlan = netdev_priv(dev);
338 struct macvtap_queue *q, *tmp;
339
340 ASSERT_RTNL();
341 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) {
342 list_del_init(&q->next);
343 RCU_INIT_POINTER(q->vlan, NULL);
344 if (q->enabled)
345 vlan->numvtaps--;
346 vlan->numqueues--;
347 sock_put(&q->sk);
348 }
349 BUG_ON(vlan->numvtaps);
350 BUG_ON(vlan->numqueues);
351 /* guarantee that any future macvtap_set_queue will fail */
352 vlan->numvtaps = MAX_MACVTAP_QUEUES;
353 }
354
355 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
356 {
357 struct sk_buff *skb = *pskb;
358 struct net_device *dev = skb->dev;
359 struct macvlan_dev *vlan;
360 struct macvtap_queue *q;
361 netdev_features_t features = TAP_FEATURES;
362
363 vlan = macvtap_get_vlan_rcu(dev);
364 if (!vlan)
365 return RX_HANDLER_PASS;
366
367 q = macvtap_get_queue(dev, skb);
368 if (!q)
369 return RX_HANDLER_PASS;
370
371 if (__skb_array_full(&q->skb_array))
372 goto drop;
373
374 skb_push(skb, ETH_HLEN);
375
376 /* Apply the forward feature mask so that we perform segmentation
377 * according to users wishes. This only works if VNET_HDR is
378 * enabled.
379 */
380 if (q->flags & IFF_VNET_HDR)
381 features |= vlan->tap_features;
382 if (netif_needs_gso(skb, features)) {
383 struct sk_buff *segs = __skb_gso_segment(skb, features, false);
384
385 if (IS_ERR(segs))
386 goto drop;
387
388 if (!segs) {
389 if (skb_array_produce(&q->skb_array, skb))
390 goto drop;
391 goto wake_up;
392 }
393
394 consume_skb(skb);
395 while (segs) {
396 struct sk_buff *nskb = segs->next;
397
398 segs->next = NULL;
399 if (skb_array_produce(&q->skb_array, segs)) {
400 kfree_skb(segs);
401 kfree_skb_list(nskb);
402 break;
403 }
404 segs = nskb;
405 }
406 } else {
407 /* If we receive a partial checksum and the tap side
408 * doesn't support checksum offload, compute the checksum.
409 * Note: it doesn't matter which checksum feature to
410 * check, we either support them all or none.
411 */
412 if (skb->ip_summed == CHECKSUM_PARTIAL &&
413 !(features & NETIF_F_CSUM_MASK) &&
414 skb_checksum_help(skb))
415 goto drop;
416 if (skb_array_produce(&q->skb_array, skb))
417 goto drop;
418 }
419
420 wake_up:
421 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
422 return RX_HANDLER_CONSUMED;
423
424 drop:
425 /* Count errors/drops only here, thus don't care about args. */
426 macvlan_count_rx(vlan, 0, 0, 0);
427 kfree_skb(skb);
428 return RX_HANDLER_CONSUMED;
429 }
430
431 static int macvtap_get_minor(struct macvlan_dev *vlan)
432 {
433 int retval = -ENOMEM;
434
435 mutex_lock(&minor_lock);
436 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL);
437 if (retval >= 0) {
438 vlan->minor = retval;
439 } else if (retval == -ENOSPC) {
440 printk(KERN_ERR "too many macvtap devices\n");
441 retval = -EINVAL;
442 }
443 mutex_unlock(&minor_lock);
444 return retval < 0 ? retval : 0;
445 }
446
447 static void macvtap_free_minor(struct macvlan_dev *vlan)
448 {
449 mutex_lock(&minor_lock);
450 if (vlan->minor) {
451 idr_remove(&minor_idr, vlan->minor);
452 vlan->minor = 0;
453 }
454 mutex_unlock(&minor_lock);
455 }
456
457 static struct net_device *dev_get_by_macvtap_minor(int minor)
458 {
459 struct net_device *dev = NULL;
460 struct macvlan_dev *vlan;
461
462 mutex_lock(&minor_lock);
463 vlan = idr_find(&minor_idr, minor);
464 if (vlan) {
465 dev = vlan->dev;
466 dev_hold(dev);
467 }
468 mutex_unlock(&minor_lock);
469 return dev;
470 }
471
472 static int macvtap_newlink(struct net *src_net,
473 struct net_device *dev,
474 struct nlattr *tb[],
475 struct nlattr *data[])
476 {
477 struct macvlan_dev *vlan = netdev_priv(dev);
478 int err;
479
480 INIT_LIST_HEAD(&vlan->queue_list);
481
482 /* Since macvlan supports all offloads by default, make
483 * tap support all offloads also.
484 */
485 vlan->tap_features = TUN_OFFLOADS;
486
487 err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
488 if (err)
489 return err;
490
491 /* Don't put anything that may fail after macvlan_common_newlink
492 * because we can't undo what it does.
493 */
494 return macvlan_common_newlink(src_net, dev, tb, data);
495 }
496
497 static void macvtap_dellink(struct net_device *dev,
498 struct list_head *head)
499 {
500 netdev_rx_handler_unregister(dev);
501 macvtap_del_queues(dev);
502 macvlan_dellink(dev, head);
503 }
504
505 static void macvtap_setup(struct net_device *dev)
506 {
507 macvlan_common_setup(dev);
508 dev->tx_queue_len = TUN_READQ_SIZE;
509 }
510
511 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
512 .kind = "macvtap",
513 .setup = macvtap_setup,
514 .newlink = macvtap_newlink,
515 .dellink = macvtap_dellink,
516 };
517
518
519 static void macvtap_sock_write_space(struct sock *sk)
520 {
521 wait_queue_head_t *wqueue;
522
523 if (!sock_writeable(sk) ||
524 !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
525 return;
526
527 wqueue = sk_sleep(sk);
528 if (wqueue && waitqueue_active(wqueue))
529 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
530 }
531
532 static void macvtap_sock_destruct(struct sock *sk)
533 {
534 struct macvtap_queue *q = container_of(sk, struct macvtap_queue, sk);
535
536 skb_array_cleanup(&q->skb_array);
537 }
538
539 static int macvtap_open(struct inode *inode, struct file *file)
540 {
541 struct net *net = current->nsproxy->net_ns;
542 struct net_device *dev;
543 struct macvtap_queue *q;
544 int err = -ENODEV;
545
546 rtnl_lock();
547 dev = dev_get_by_macvtap_minor(iminor(inode));
548 if (!dev)
549 goto err;
550
551 err = -ENOMEM;
552 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
553 &macvtap_proto, 0);
554 if (!q)
555 goto err;
556
557 RCU_INIT_POINTER(q->sock.wq, &q->wq);
558 init_waitqueue_head(&q->wq.wait);
559 q->sock.type = SOCK_RAW;
560 q->sock.state = SS_CONNECTED;
561 q->sock.file = file;
562 q->sock.ops = &macvtap_socket_ops;
563 sock_init_data(&q->sock, &q->sk);
564 q->sk.sk_write_space = macvtap_sock_write_space;
565 q->sk.sk_destruct = macvtap_sock_destruct;
566 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
567 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
568
569 /*
570 * so far only KVM virtio_net uses macvtap, enable zero copy between
571 * guest kernel and host kernel when lower device supports zerocopy
572 *
573 * The macvlan supports zerocopy iff the lower device supports zero
574 * copy so we don't have to look at the lower device directly.
575 */
576 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
577 sock_set_flag(&q->sk, SOCK_ZEROCOPY);
578
579 err = -ENOMEM;
580 if (skb_array_init(&q->skb_array, dev->tx_queue_len, GFP_KERNEL))
581 goto err_array;
582
583 err = macvtap_set_queue(dev, file, q);
584 if (err)
585 goto err_queue;
586
587 dev_put(dev);
588
589 rtnl_unlock();
590 return err;
591
592 err_queue:
593 skb_array_cleanup(&q->skb_array);
594 err_array:
595 sock_put(&q->sk);
596 err:
597 if (dev)
598 dev_put(dev);
599
600 rtnl_unlock();
601 return err;
602 }
603
604 static int macvtap_release(struct inode *inode, struct file *file)
605 {
606 struct macvtap_queue *q = file->private_data;
607 macvtap_put_queue(q);
608 return 0;
609 }
610
611 static unsigned int macvtap_poll(struct file *file, poll_table * wait)
612 {
613 struct macvtap_queue *q = file->private_data;
614 unsigned int mask = POLLERR;
615
616 if (!q)
617 goto out;
618
619 mask = 0;
620 poll_wait(file, &q->wq.wait, wait);
621
622 if (!skb_array_empty(&q->skb_array))
623 mask |= POLLIN | POLLRDNORM;
624
625 if (sock_writeable(&q->sk) ||
626 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
627 sock_writeable(&q->sk)))
628 mask |= POLLOUT | POLLWRNORM;
629
630 out:
631 return mask;
632 }
633
634 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
635 size_t len, size_t linear,
636 int noblock, int *err)
637 {
638 struct sk_buff *skb;
639
640 /* Under a page? Don't bother with paged skb. */
641 if (prepad + len < PAGE_SIZE || !linear)
642 linear = len;
643
644 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
645 err, 0);
646 if (!skb)
647 return NULL;
648
649 skb_reserve(skb, prepad);
650 skb_put(skb, linear);
651 skb->data_len = len - linear;
652 skb->len += len - linear;
653
654 return skb;
655 }
656
657 /* Neighbour code has some assumptions on HH_DATA_MOD alignment */
658 #define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
659
660 /* Get packet from user space buffer */
661 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
662 struct iov_iter *from, int noblock)
663 {
664 int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
665 struct sk_buff *skb;
666 struct macvlan_dev *vlan;
667 unsigned long total_len = iov_iter_count(from);
668 unsigned long len = total_len;
669 int err;
670 struct virtio_net_hdr vnet_hdr = { 0 };
671 int vnet_hdr_len = 0;
672 int copylen = 0;
673 int depth;
674 bool zerocopy = false;
675 size_t linear;
676 ssize_t n;
677
678 if (q->flags & IFF_VNET_HDR) {
679 vnet_hdr_len = q->vnet_hdr_sz;
680
681 err = -EINVAL;
682 if (len < vnet_hdr_len)
683 goto err;
684 len -= vnet_hdr_len;
685
686 err = -EFAULT;
687 n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from);
688 if (n != sizeof(vnet_hdr))
689 goto err;
690 iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
691 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
692 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
693 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
694 macvtap16_to_cpu(q, vnet_hdr.hdr_len))
695 vnet_hdr.hdr_len = cpu_to_macvtap16(q,
696 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
697 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
698 err = -EINVAL;
699 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
700 goto err;
701 }
702
703 err = -EINVAL;
704 if (unlikely(len < ETH_HLEN))
705 goto err;
706
707 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
708 struct iov_iter i;
709
710 copylen = vnet_hdr.hdr_len ?
711 macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
712 if (copylen > good_linear)
713 copylen = good_linear;
714 else if (copylen < ETH_HLEN)
715 copylen = ETH_HLEN;
716 linear = copylen;
717 i = *from;
718 iov_iter_advance(&i, copylen);
719 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
720 zerocopy = true;
721 }
722
723 if (!zerocopy) {
724 copylen = len;
725 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
726 if (linear > good_linear)
727 linear = good_linear;
728 else if (linear < ETH_HLEN)
729 linear = ETH_HLEN;
730 }
731
732 skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
733 linear, noblock, &err);
734 if (!skb)
735 goto err;
736
737 if (zerocopy)
738 err = zerocopy_sg_from_iter(skb, from);
739 else {
740 err = skb_copy_datagram_from_iter(skb, 0, from, len);
741 if (!err && m && m->msg_control) {
742 struct ubuf_info *uarg = m->msg_control;
743 uarg->callback(uarg, false);
744 }
745 }
746
747 if (err)
748 goto err_kfree;
749
750 skb_set_network_header(skb, ETH_HLEN);
751 skb_reset_mac_header(skb);
752 skb->protocol = eth_hdr(skb)->h_proto;
753
754 if (vnet_hdr_len) {
755 err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
756 macvtap_is_little_endian(q));
757 if (err)
758 goto err_kfree;
759 }
760
761 skb_probe_transport_header(skb, ETH_HLEN);
762
763 /* Move network header to the right position for VLAN tagged packets */
764 if ((skb->protocol == htons(ETH_P_8021Q) ||
765 skb->protocol == htons(ETH_P_8021AD)) &&
766 __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
767 skb_set_network_header(skb, depth);
768
769 rcu_read_lock();
770 vlan = rcu_dereference(q->vlan);
771 /* copy skb_ubuf_info for callback when skb has no error */
772 if (zerocopy) {
773 skb_shinfo(skb)->destructor_arg = m->msg_control;
774 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
775 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
776 }
777 if (vlan) {
778 skb->dev = vlan->dev;
779 dev_queue_xmit(skb);
780 } else {
781 kfree_skb(skb);
782 }
783 rcu_read_unlock();
784
785 return total_len;
786
787 err_kfree:
788 kfree_skb(skb);
789
790 err:
791 rcu_read_lock();
792 vlan = rcu_dereference(q->vlan);
793 if (vlan)
794 this_cpu_inc(vlan->pcpu_stats->tx_dropped);
795 rcu_read_unlock();
796
797 return err;
798 }
799
800 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
801 {
802 struct file *file = iocb->ki_filp;
803 struct macvtap_queue *q = file->private_data;
804
805 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
806 }
807
808 /* Put packet to the user space buffer */
809 static ssize_t macvtap_put_user(struct macvtap_queue *q,
810 const struct sk_buff *skb,
811 struct iov_iter *iter)
812 {
813 int ret;
814 int vnet_hdr_len = 0;
815 int vlan_offset = 0;
816 int total;
817
818 if (q->flags & IFF_VNET_HDR) {
819 struct virtio_net_hdr vnet_hdr;
820 vnet_hdr_len = q->vnet_hdr_sz;
821 if (iov_iter_count(iter) < vnet_hdr_len)
822 return -EINVAL;
823
824 ret = virtio_net_hdr_from_skb(skb, &vnet_hdr,
825 macvtap_is_little_endian(q));
826 if (ret)
827 BUG();
828
829 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
830 sizeof(vnet_hdr))
831 return -EFAULT;
832
833 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
834 }
835 total = vnet_hdr_len;
836 total += skb->len;
837
838 if (skb_vlan_tag_present(skb)) {
839 struct {
840 __be16 h_vlan_proto;
841 __be16 h_vlan_TCI;
842 } veth;
843 veth.h_vlan_proto = skb->vlan_proto;
844 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
845
846 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
847 total += VLAN_HLEN;
848
849 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
850 if (ret || !iov_iter_count(iter))
851 goto done;
852
853 ret = copy_to_iter(&veth, sizeof(veth), iter);
854 if (ret != sizeof(veth) || !iov_iter_count(iter))
855 goto done;
856 }
857
858 ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
859 skb->len - vlan_offset);
860
861 done:
862 return ret ? ret : total;
863 }
864
865 static ssize_t macvtap_do_read(struct macvtap_queue *q,
866 struct iov_iter *to,
867 int noblock)
868 {
869 DEFINE_WAIT(wait);
870 struct sk_buff *skb;
871 ssize_t ret = 0;
872
873 if (!iov_iter_count(to))
874 return 0;
875
876 while (1) {
877 if (!noblock)
878 prepare_to_wait(sk_sleep(&q->sk), &wait,
879 TASK_INTERRUPTIBLE);
880
881 /* Read frames from the queue */
882 skb = skb_array_consume(&q->skb_array);
883 if (skb)
884 break;
885 if (noblock) {
886 ret = -EAGAIN;
887 break;
888 }
889 if (signal_pending(current)) {
890 ret = -ERESTARTSYS;
891 break;
892 }
893 /* Nothing to read, let's sleep */
894 schedule();
895 }
896 if (!noblock)
897 finish_wait(sk_sleep(&q->sk), &wait);
898
899 if (skb) {
900 ret = macvtap_put_user(q, skb, to);
901 if (unlikely(ret < 0))
902 kfree_skb(skb);
903 else
904 consume_skb(skb);
905 }
906 return ret;
907 }
908
909 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
910 {
911 struct file *file = iocb->ki_filp;
912 struct macvtap_queue *q = file->private_data;
913 ssize_t len = iov_iter_count(to), ret;
914
915 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
916 ret = min_t(ssize_t, ret, len);
917 if (ret > 0)
918 iocb->ki_pos = ret;
919 return ret;
920 }
921
922 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
923 {
924 struct macvlan_dev *vlan;
925
926 ASSERT_RTNL();
927 vlan = rtnl_dereference(q->vlan);
928 if (vlan)
929 dev_hold(vlan->dev);
930
931 return vlan;
932 }
933
934 static void macvtap_put_vlan(struct macvlan_dev *vlan)
935 {
936 dev_put(vlan->dev);
937 }
938
939 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
940 {
941 struct macvtap_queue *q = file->private_data;
942 struct macvlan_dev *vlan;
943 int ret;
944
945 vlan = macvtap_get_vlan(q);
946 if (!vlan)
947 return -EINVAL;
948
949 if (flags & IFF_ATTACH_QUEUE)
950 ret = macvtap_enable_queue(vlan->dev, file, q);
951 else if (flags & IFF_DETACH_QUEUE)
952 ret = macvtap_disable_queue(q);
953 else
954 ret = -EINVAL;
955
956 macvtap_put_vlan(vlan);
957 return ret;
958 }
959
960 static int set_offload(struct macvtap_queue *q, unsigned long arg)
961 {
962 struct macvlan_dev *vlan;
963 netdev_features_t features;
964 netdev_features_t feature_mask = 0;
965
966 vlan = rtnl_dereference(q->vlan);
967 if (!vlan)
968 return -ENOLINK;
969
970 features = vlan->dev->features;
971
972 if (arg & TUN_F_CSUM) {
973 feature_mask = NETIF_F_HW_CSUM;
974
975 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
976 if (arg & TUN_F_TSO_ECN)
977 feature_mask |= NETIF_F_TSO_ECN;
978 if (arg & TUN_F_TSO4)
979 feature_mask |= NETIF_F_TSO;
980 if (arg & TUN_F_TSO6)
981 feature_mask |= NETIF_F_TSO6;
982 }
983
984 if (arg & TUN_F_UFO)
985 feature_mask |= NETIF_F_UFO;
986 }
987
988 /* tun/tap driver inverts the usage for TSO offloads, where
989 * setting the TSO bit means that the userspace wants to
990 * accept TSO frames and turning it off means that user space
991 * does not support TSO.
992 * For macvtap, we have to invert it to mean the same thing.
993 * When user space turns off TSO, we turn off GSO/LRO so that
994 * user-space will not receive TSO frames.
995 */
996 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
997 features |= RX_OFFLOADS;
998 else
999 features &= ~RX_OFFLOADS;
1000
1001 /* tap_features are the same as features on tun/tap and
1002 * reflect user expectations.
1003 */
1004 vlan->tap_features = feature_mask;
1005 vlan->set_features = features;
1006 netdev_update_features(vlan->dev);
1007
1008 return 0;
1009 }
1010
1011 /*
1012 * provide compatibility with generic tun/tap interface
1013 */
1014 static long macvtap_ioctl(struct file *file, unsigned int cmd,
1015 unsigned long arg)
1016 {
1017 struct macvtap_queue *q = file->private_data;
1018 struct macvlan_dev *vlan;
1019 void __user *argp = (void __user *)arg;
1020 struct ifreq __user *ifr = argp;
1021 unsigned int __user *up = argp;
1022 unsigned short u;
1023 int __user *sp = argp;
1024 struct sockaddr sa;
1025 int s;
1026 int ret;
1027
1028 switch (cmd) {
1029 case TUNSETIFF:
1030 /* ignore the name, just look at flags */
1031 if (get_user(u, &ifr->ifr_flags))
1032 return -EFAULT;
1033
1034 ret = 0;
1035 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
1036 ret = -EINVAL;
1037 else
1038 q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
1039
1040 return ret;
1041
1042 case TUNGETIFF:
1043 rtnl_lock();
1044 vlan = macvtap_get_vlan(q);
1045 if (!vlan) {
1046 rtnl_unlock();
1047 return -ENOLINK;
1048 }
1049
1050 ret = 0;
1051 u = q->flags;
1052 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1053 put_user(u, &ifr->ifr_flags))
1054 ret = -EFAULT;
1055 macvtap_put_vlan(vlan);
1056 rtnl_unlock();
1057 return ret;
1058
1059 case TUNSETQUEUE:
1060 if (get_user(u, &ifr->ifr_flags))
1061 return -EFAULT;
1062 rtnl_lock();
1063 ret = macvtap_ioctl_set_queue(file, u);
1064 rtnl_unlock();
1065 return ret;
1066
1067 case TUNGETFEATURES:
1068 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
1069 return -EFAULT;
1070 return 0;
1071
1072 case TUNSETSNDBUF:
1073 if (get_user(s, sp))
1074 return -EFAULT;
1075
1076 q->sk.sk_sndbuf = s;
1077 return 0;
1078
1079 case TUNGETVNETHDRSZ:
1080 s = q->vnet_hdr_sz;
1081 if (put_user(s, sp))
1082 return -EFAULT;
1083 return 0;
1084
1085 case TUNSETVNETHDRSZ:
1086 if (get_user(s, sp))
1087 return -EFAULT;
1088 if (s < (int)sizeof(struct virtio_net_hdr))
1089 return -EINVAL;
1090
1091 q->vnet_hdr_sz = s;
1092 return 0;
1093
1094 case TUNGETVNETLE:
1095 s = !!(q->flags & MACVTAP_VNET_LE);
1096 if (put_user(s, sp))
1097 return -EFAULT;
1098 return 0;
1099
1100 case TUNSETVNETLE:
1101 if (get_user(s, sp))
1102 return -EFAULT;
1103 if (s)
1104 q->flags |= MACVTAP_VNET_LE;
1105 else
1106 q->flags &= ~MACVTAP_VNET_LE;
1107 return 0;
1108
1109 case TUNGETVNETBE:
1110 return macvtap_get_vnet_be(q, sp);
1111
1112 case TUNSETVNETBE:
1113 return macvtap_set_vnet_be(q, sp);
1114
1115 case TUNSETOFFLOAD:
1116 /* let the user check for future flags */
1117 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
1118 TUN_F_TSO_ECN | TUN_F_UFO))
1119 return -EINVAL;
1120
1121 rtnl_lock();
1122 ret = set_offload(q, arg);
1123 rtnl_unlock();
1124 return ret;
1125
1126 case SIOCGIFHWADDR:
1127 rtnl_lock();
1128 vlan = macvtap_get_vlan(q);
1129 if (!vlan) {
1130 rtnl_unlock();
1131 return -ENOLINK;
1132 }
1133 ret = 0;
1134 u = vlan->dev->type;
1135 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1136 copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
1137 put_user(u, &ifr->ifr_hwaddr.sa_family))
1138 ret = -EFAULT;
1139 macvtap_put_vlan(vlan);
1140 rtnl_unlock();
1141 return ret;
1142
1143 case SIOCSIFHWADDR:
1144 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
1145 return -EFAULT;
1146 rtnl_lock();
1147 vlan = macvtap_get_vlan(q);
1148 if (!vlan) {
1149 rtnl_unlock();
1150 return -ENOLINK;
1151 }
1152 ret = dev_set_mac_address(vlan->dev, &sa);
1153 macvtap_put_vlan(vlan);
1154 rtnl_unlock();
1155 return ret;
1156
1157 default:
1158 return -EINVAL;
1159 }
1160 }
1161
1162 #ifdef CONFIG_COMPAT
1163 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
1164 unsigned long arg)
1165 {
1166 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1167 }
1168 #endif
1169
1170 static const struct file_operations macvtap_fops = {
1171 .owner = THIS_MODULE,
1172 .open = macvtap_open,
1173 .release = macvtap_release,
1174 .read_iter = macvtap_read_iter,
1175 .write_iter = macvtap_write_iter,
1176 .poll = macvtap_poll,
1177 .llseek = no_llseek,
1178 .unlocked_ioctl = macvtap_ioctl,
1179 #ifdef CONFIG_COMPAT
1180 .compat_ioctl = macvtap_compat_ioctl,
1181 #endif
1182 };
1183
1184 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
1185 size_t total_len)
1186 {
1187 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1188 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
1189 }
1190
1191 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
1192 size_t total_len, int flags)
1193 {
1194 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1195 int ret;
1196 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1197 return -EINVAL;
1198 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
1199 if (ret > total_len) {
1200 m->msg_flags |= MSG_TRUNC;
1201 ret = flags & MSG_TRUNC ? ret : total_len;
1202 }
1203 return ret;
1204 }
1205
1206 static int macvtap_peek_len(struct socket *sock)
1207 {
1208 struct macvtap_queue *q = container_of(sock, struct macvtap_queue,
1209 sock);
1210 return skb_array_peek_len(&q->skb_array);
1211 }
1212
1213 /* Ops structure to mimic raw sockets with tun */
1214 static const struct proto_ops macvtap_socket_ops = {
1215 .sendmsg = macvtap_sendmsg,
1216 .recvmsg = macvtap_recvmsg,
1217 .peek_len = macvtap_peek_len,
1218 };
1219
1220 /* Get an underlying socket object from tun file. Returns error unless file is
1221 * attached to a device. The returned object works like a packet socket, it
1222 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1223 * holding a reference to the file for as long as the socket is in use. */
1224 struct socket *macvtap_get_socket(struct file *file)
1225 {
1226 struct macvtap_queue *q;
1227 if (file->f_op != &macvtap_fops)
1228 return ERR_PTR(-EINVAL);
1229 q = file->private_data;
1230 if (!q)
1231 return ERR_PTR(-EBADFD);
1232 return &q->sock;
1233 }
1234 EXPORT_SYMBOL_GPL(macvtap_get_socket);
1235
1236 static int macvtap_queue_resize(struct macvlan_dev *vlan)
1237 {
1238 struct net_device *dev = vlan->dev;
1239 struct macvtap_queue *q;
1240 struct skb_array **arrays;
1241 int n = vlan->numqueues;
1242 int ret, i = 0;
1243
1244 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
1245 if (!arrays)
1246 return -ENOMEM;
1247
1248 list_for_each_entry(q, &vlan->queue_list, next)
1249 arrays[i++] = &q->skb_array;
1250
1251 ret = skb_array_resize_multiple(arrays, n,
1252 dev->tx_queue_len, GFP_KERNEL);
1253
1254 kfree(arrays);
1255 return ret;
1256 }
1257
1258 static int macvtap_device_event(struct notifier_block *unused,
1259 unsigned long event, void *ptr)
1260 {
1261 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1262 struct macvlan_dev *vlan;
1263 struct device *classdev;
1264 dev_t devt;
1265 int err;
1266 char tap_name[IFNAMSIZ];
1267
1268 if (dev->rtnl_link_ops != &macvtap_link_ops)
1269 return NOTIFY_DONE;
1270
1271 snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
1272 vlan = netdev_priv(dev);
1273
1274 switch (event) {
1275 case NETDEV_REGISTER:
1276 /* Create the device node here after the network device has
1277 * been registered but before register_netdevice has
1278 * finished running.
1279 */
1280 err = macvtap_get_minor(vlan);
1281 if (err)
1282 return notifier_from_errno(err);
1283
1284 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1285 classdev = device_create(&macvtap_class, &dev->dev, devt,
1286 dev, tap_name);
1287 if (IS_ERR(classdev)) {
1288 macvtap_free_minor(vlan);
1289 return notifier_from_errno(PTR_ERR(classdev));
1290 }
1291 err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
1292 tap_name);
1293 if (err)
1294 return notifier_from_errno(err);
1295 break;
1296 case NETDEV_UNREGISTER:
1297 /* vlan->minor == 0 if NETDEV_REGISTER above failed */
1298 if (vlan->minor == 0)
1299 break;
1300 sysfs_remove_link(&dev->dev.kobj, tap_name);
1301 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1302 device_destroy(&macvtap_class, devt);
1303 macvtap_free_minor(vlan);
1304 break;
1305 case NETDEV_CHANGE_TX_QUEUE_LEN:
1306 if (macvtap_queue_resize(vlan))
1307 return NOTIFY_BAD;
1308 break;
1309 }
1310
1311 return NOTIFY_DONE;
1312 }
1313
1314 static struct notifier_block macvtap_notifier_block __read_mostly = {
1315 .notifier_call = macvtap_device_event,
1316 };
1317
1318 static int macvtap_init(void)
1319 {
1320 int err;
1321
1322 err = alloc_chrdev_region(&macvtap_major, 0,
1323 MACVTAP_NUM_DEVS, "macvtap");
1324 if (err)
1325 goto out1;
1326
1327 cdev_init(&macvtap_cdev, &macvtap_fops);
1328 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1329 if (err)
1330 goto out2;
1331
1332 err = class_register(&macvtap_class);
1333 if (err)
1334 goto out3;
1335
1336 err = register_netdevice_notifier(&macvtap_notifier_block);
1337 if (err)
1338 goto out4;
1339
1340 err = macvlan_link_register(&macvtap_link_ops);
1341 if (err)
1342 goto out5;
1343
1344 return 0;
1345
1346 out5:
1347 unregister_netdevice_notifier(&macvtap_notifier_block);
1348 out4:
1349 class_unregister(&macvtap_class);
1350 out3:
1351 cdev_del(&macvtap_cdev);
1352 out2:
1353 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1354 out1:
1355 return err;
1356 }
1357 module_init(macvtap_init);
1358
1359 static void macvtap_exit(void)
1360 {
1361 rtnl_link_unregister(&macvtap_link_ops);
1362 unregister_netdevice_notifier(&macvtap_notifier_block);
1363 class_unregister(&macvtap_class);
1364 cdev_del(&macvtap_cdev);
1365 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1366 idr_destroy(&minor_idr);
1367 }
1368 module_exit(macvtap_exit);
1369
1370 MODULE_ALIAS_RTNL_LINK("macvtap");
1371 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1372 MODULE_LICENSE("GPL");
Linux with added FPC-III support