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1 | #include <linux/etherdevice.h> |
2 | #include <linux/if_macvlan.h> |
3 | #include <linux/if_vlan.h> |
4 | #include <linux/interrupt.h> |
5 | #include <linux/nsproxy.h> |
6 | #include <linux/compat.h> |
7 | #include <linux/if_tun.h> |
8 | #include <linux/module.h> |
9 | #include <linux/skbuff.h> |
10 | #include <linux/cache.h> |
11 | #include <linux/sched.h> |
12 | #include <linux/types.h> |
13 | #include <linux/slab.h> |
14 | #include <linux/init.h> |
15 | #include <linux/wait.h> |
16 | #include <linux/cdev.h> |
17 | #include <linux/idr.h> |
18 | #include <linux/fs.h> |
19 | |
20 | #include <net/net_namespace.h> |
21 | #include <net/rtnetlink.h> |
22 | #include <net/sock.h> |
23 | #include <linux/virtio_net.h> |
24 | |
25 | /* |
26 | * A macvtap queue is the central object of this driver, it connects |
27 | * an open character device to a macvlan interface. There can be |
28 | * multiple queues on one interface, which map back to queues |
29 | * implemented in hardware on the underlying device. |
30 | * |
31 | * macvtap_proto is used to allocate queues through the sock allocation |
32 | * mechanism. |
33 | * |
34 | * TODO: multiqueue support is currently not implemented, even though |
35 | * macvtap is basically prepared for that. We will need to add this |
36 | * here as well as in virtio-net and qemu to get line rate on 10gbit |
37 | * adapters from a guest. |
38 | */ |
39 | struct macvtap_queue { |
40 | struct sock sk; |
41 | struct socket sock; |
42 | struct socket_wq wq; |
43 | int vnet_hdr_sz; |
44 | struct macvlan_dev __rcu *vlan; |
45 | struct file *file; |
46 | unsigned int flags; |
47 | }; |
48 | |
49 | static struct proto macvtap_proto = { |
50 | .name = "macvtap", |
51 | .owner = THIS_MODULE, |
52 | .obj_size = sizeof (struct macvtap_queue), |
53 | }; |
54 | |
55 | /* |
56 | * Variables for dealing with macvtaps device numbers. |
57 | */ |
58 | static dev_t macvtap_major; |
59 | #define MACVTAP_NUM_DEVS (1U << MINORBITS) |
60 | static DEFINE_MUTEX(minor_lock); |
61 | static DEFINE_IDR(minor_idr); |
62 | |
63 | #define GOODCOPY_LEN 128 |
64 | static struct class *macvtap_class; |
65 | static struct cdev macvtap_cdev; |
66 | |
67 | static const struct proto_ops macvtap_socket_ops; |
68 | |
69 | /* |
70 | * RCU usage: |
71 | * The macvtap_queue and the macvlan_dev are loosely coupled, the |
72 | * pointers from one to the other can only be read while rcu_read_lock |
73 | * or macvtap_lock is held. |
74 | * |
75 | * Both the file and the macvlan_dev hold a reference on the macvtap_queue |
76 | * through sock_hold(&q->sk). When the macvlan_dev goes away first, |
77 | * q->vlan becomes inaccessible. When the files gets closed, |
78 | * macvtap_get_queue() fails. |
79 | * |
80 | * There may still be references to the struct sock inside of the |
81 | * queue from outbound SKBs, but these never reference back to the |
82 | * file or the dev. The data structure is freed through __sk_free |
83 | * when both our references and any pending SKBs are gone. |
84 | */ |
85 | static DEFINE_SPINLOCK(macvtap_lock); |
86 | |
87 | /* |
88 | * get_slot: return a [unused/occupied] slot in vlan->taps[]: |
89 | * - if 'q' is NULL, return the first empty slot; |
90 | * - otherwise, return the slot this pointer occupies. |
91 | */ |
92 | static int get_slot(struct macvlan_dev *vlan, struct macvtap_queue *q) |
93 | { |
94 | int i; |
95 | |
96 | for (i = 0; i < MAX_MACVTAP_QUEUES; i++) { |
97 | if (rcu_dereference_protected(vlan->taps[i], |
98 | lockdep_is_held(&macvtap_lock)) == q) |
99 | return i; |
100 | } |
101 | |
102 | /* Should never happen */ |
103 | BUG_ON(1); |
104 | } |
105 | |
106 | static int macvtap_set_queue(struct net_device *dev, struct file *file, |
107 | struct macvtap_queue *q) |
108 | { |
109 | struct macvlan_dev *vlan = netdev_priv(dev); |
110 | int index; |
111 | int err = -EBUSY; |
112 | |
113 | spin_lock(&macvtap_lock); |
114 | if (vlan->numvtaps == MAX_MACVTAP_QUEUES) |
115 | goto out; |
116 | |
117 | err = 0; |
118 | index = get_slot(vlan, NULL); |
119 | rcu_assign_pointer(q->vlan, vlan); |
120 | rcu_assign_pointer(vlan->taps[index], q); |
121 | sock_hold(&q->sk); |
122 | |
123 | q->file = file; |
124 | file->private_data = q; |
125 | |
126 | vlan->numvtaps++; |
127 | |
128 | out: |
129 | spin_unlock(&macvtap_lock); |
130 | return err; |
131 | } |
132 | |
133 | /* |
134 | * The file owning the queue got closed, give up both |
135 | * the reference that the files holds as well as the |
136 | * one from the macvlan_dev if that still exists. |
137 | * |
138 | * Using the spinlock makes sure that we don't get |
139 | * to the queue again after destroying it. |
140 | */ |
141 | static void macvtap_put_queue(struct macvtap_queue *q) |
142 | { |
143 | struct macvlan_dev *vlan; |
144 | |
145 | spin_lock(&macvtap_lock); |
146 | vlan = rcu_dereference_protected(q->vlan, |
147 | lockdep_is_held(&macvtap_lock)); |
148 | if (vlan) { |
149 | int index = get_slot(vlan, q); |
150 | |
151 | RCU_INIT_POINTER(vlan->taps[index], NULL); |
152 | RCU_INIT_POINTER(q->vlan, NULL); |
153 | sock_put(&q->sk); |
154 | --vlan->numvtaps; |
155 | } |
156 | |
157 | spin_unlock(&macvtap_lock); |
158 | |
159 | synchronize_rcu(); |
160 | sock_put(&q->sk); |
161 | } |
162 | |
163 | /* |
164 | * Select a queue based on the rxq of the device on which this packet |
165 | * arrived. If the incoming device is not mq, calculate a flow hash |
166 | * to select a queue. If all fails, find the first available queue. |
167 | * Cache vlan->numvtaps since it can become zero during the execution |
168 | * of this function. |
169 | */ |
170 | static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, |
171 | struct sk_buff *skb) |
172 | { |
173 | struct macvlan_dev *vlan = netdev_priv(dev); |
174 | struct macvtap_queue *tap = NULL; |
175 | int numvtaps = vlan->numvtaps; |
176 | __u32 rxq; |
177 | |
178 | if (!numvtaps) |
179 | goto out; |
180 | |
181 | /* Check if we can use flow to select a queue */ |
182 | rxq = skb_get_rxhash(skb); |
183 | if (rxq) { |
184 | tap = rcu_dereference(vlan->taps[rxq % numvtaps]); |
185 | if (tap) |
186 | goto out; |
187 | } |
188 | |
189 | if (likely(skb_rx_queue_recorded(skb))) { |
190 | rxq = skb_get_rx_queue(skb); |
191 | |
192 | while (unlikely(rxq >= numvtaps)) |
193 | rxq -= numvtaps; |
194 | |
195 | tap = rcu_dereference(vlan->taps[rxq]); |
196 | if (tap) |
197 | goto out; |
198 | } |
199 | |
200 | /* Everything failed - find first available queue */ |
201 | for (rxq = 0; rxq < MAX_MACVTAP_QUEUES; rxq++) { |
202 | tap = rcu_dereference(vlan->taps[rxq]); |
203 | if (tap) |
204 | break; |
205 | } |
206 | |
207 | out: |
208 | return tap; |
209 | } |
210 | |
211 | /* |
212 | * The net_device is going away, give up the reference |
213 | * that it holds on all queues and safely set the pointer |
214 | * from the queues to NULL. |
215 | */ |
216 | static void macvtap_del_queues(struct net_device *dev) |
217 | { |
218 | struct macvlan_dev *vlan = netdev_priv(dev); |
219 | struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES]; |
220 | int i, j = 0; |
221 | |
222 | /* macvtap_put_queue can free some slots, so go through all slots */ |
223 | spin_lock(&macvtap_lock); |
224 | for (i = 0; i < MAX_MACVTAP_QUEUES && vlan->numvtaps; i++) { |
225 | q = rcu_dereference_protected(vlan->taps[i], |
226 | lockdep_is_held(&macvtap_lock)); |
227 | if (q) { |
228 | qlist[j++] = q; |
229 | RCU_INIT_POINTER(vlan->taps[i], NULL); |
230 | RCU_INIT_POINTER(q->vlan, NULL); |
231 | vlan->numvtaps--; |
232 | } |
233 | } |
234 | BUG_ON(vlan->numvtaps != 0); |
235 | /* guarantee that any future macvtap_set_queue will fail */ |
236 | vlan->numvtaps = MAX_MACVTAP_QUEUES; |
237 | spin_unlock(&macvtap_lock); |
238 | |
239 | synchronize_rcu(); |
240 | |
241 | for (--j; j >= 0; j--) |
242 | sock_put(&qlist[j]->sk); |
243 | } |
244 | |
245 | /* |
246 | * Forward happens for data that gets sent from one macvlan |
247 | * endpoint to another one in bridge mode. We just take |
248 | * the skb and put it into the receive queue. |
249 | */ |
250 | static int macvtap_forward(struct net_device *dev, struct sk_buff *skb) |
251 | { |
252 | struct macvtap_queue *q = macvtap_get_queue(dev, skb); |
253 | if (!q) |
254 | goto drop; |
255 | |
256 | if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) |
257 | goto drop; |
258 | |
259 | skb_queue_tail(&q->sk.sk_receive_queue, skb); |
260 | wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); |
261 | return NET_RX_SUCCESS; |
262 | |
263 | drop: |
264 | kfree_skb(skb); |
265 | return NET_RX_DROP; |
266 | } |
267 | |
268 | /* |
269 | * Receive is for data from the external interface (lowerdev), |
270 | * in case of macvtap, we can treat that the same way as |
271 | * forward, which macvlan cannot. |
272 | */ |
273 | static int macvtap_receive(struct sk_buff *skb) |
274 | { |
275 | skb_push(skb, ETH_HLEN); |
276 | return macvtap_forward(skb->dev, skb); |
277 | } |
278 | |
279 | static int macvtap_get_minor(struct macvlan_dev *vlan) |
280 | { |
281 | int retval = -ENOMEM; |
282 | int id; |
283 | |
284 | mutex_lock(&minor_lock); |
285 | if (idr_pre_get(&minor_idr, GFP_KERNEL) == 0) |
286 | goto exit; |
287 | |
288 | retval = idr_get_new_above(&minor_idr, vlan, 1, &id); |
289 | if (retval < 0) { |
290 | if (retval == -EAGAIN) |
291 | retval = -ENOMEM; |
292 | goto exit; |
293 | } |
294 | if (id < MACVTAP_NUM_DEVS) { |
295 | vlan->minor = id; |
296 | } else { |
297 | printk(KERN_ERR "too many macvtap devices\n"); |
298 | retval = -EINVAL; |
299 | idr_remove(&minor_idr, id); |
300 | } |
301 | exit: |
302 | mutex_unlock(&minor_lock); |
303 | return retval; |
304 | } |
305 | |
306 | static void macvtap_free_minor(struct macvlan_dev *vlan) |
307 | { |
308 | mutex_lock(&minor_lock); |
309 | if (vlan->minor) { |
310 | idr_remove(&minor_idr, vlan->minor); |
311 | vlan->minor = 0; |
312 | } |
313 | mutex_unlock(&minor_lock); |
314 | } |
315 | |
316 | static struct net_device *dev_get_by_macvtap_minor(int minor) |
317 | { |
318 | struct net_device *dev = NULL; |
319 | struct macvlan_dev *vlan; |
320 | |
321 | mutex_lock(&minor_lock); |
322 | vlan = idr_find(&minor_idr, minor); |
323 | if (vlan) { |
324 | dev = vlan->dev; |
325 | dev_hold(dev); |
326 | } |
327 | mutex_unlock(&minor_lock); |
328 | return dev; |
329 | } |
330 | |
331 | static int macvtap_newlink(struct net *src_net, |
332 | struct net_device *dev, |
333 | struct nlattr *tb[], |
334 | struct nlattr *data[]) |
335 | { |
336 | /* Don't put anything that may fail after macvlan_common_newlink |
337 | * because we can't undo what it does. |
338 | */ |
339 | return macvlan_common_newlink(src_net, dev, tb, data, |
340 | macvtap_receive, macvtap_forward); |
341 | } |
342 | |
343 | static void macvtap_dellink(struct net_device *dev, |
344 | struct list_head *head) |
345 | { |
346 | macvtap_del_queues(dev); |
347 | macvlan_dellink(dev, head); |
348 | } |
349 | |
350 | static void macvtap_setup(struct net_device *dev) |
351 | { |
352 | macvlan_common_setup(dev); |
353 | dev->tx_queue_len = TUN_READQ_SIZE; |
354 | } |
355 | |
356 | static struct rtnl_link_ops macvtap_link_ops __read_mostly = { |
357 | .kind = "macvtap", |
358 | .setup = macvtap_setup, |
359 | .newlink = macvtap_newlink, |
360 | .dellink = macvtap_dellink, |
361 | }; |
362 | |
363 | |
364 | static void macvtap_sock_write_space(struct sock *sk) |
365 | { |
366 | wait_queue_head_t *wqueue; |
367 | |
368 | if (!sock_writeable(sk) || |
369 | !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) |
370 | return; |
371 | |
372 | wqueue = sk_sleep(sk); |
373 | if (wqueue && waitqueue_active(wqueue)) |
374 | wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); |
375 | } |
376 | |
377 | static void macvtap_sock_destruct(struct sock *sk) |
378 | { |
379 | skb_queue_purge(&sk->sk_receive_queue); |
380 | } |
381 | |
382 | static int macvtap_open(struct inode *inode, struct file *file) |
383 | { |
384 | struct net *net = current->nsproxy->net_ns; |
385 | struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode)); |
386 | struct macvtap_queue *q; |
387 | int err; |
388 | |
389 | err = -ENODEV; |
390 | if (!dev) |
391 | goto out; |
392 | |
393 | err = -ENOMEM; |
394 | q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, |
395 | &macvtap_proto); |
396 | if (!q) |
397 | goto out; |
398 | |
399 | q->sock.wq = &q->wq; |
400 | init_waitqueue_head(&q->wq.wait); |
401 | q->sock.type = SOCK_RAW; |
402 | q->sock.state = SS_CONNECTED; |
403 | q->sock.file = file; |
404 | q->sock.ops = &macvtap_socket_ops; |
405 | sock_init_data(&q->sock, &q->sk); |
406 | q->sk.sk_write_space = macvtap_sock_write_space; |
407 | q->sk.sk_destruct = macvtap_sock_destruct; |
408 | q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; |
409 | q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); |
410 | |
411 | /* |
412 | * so far only KVM virtio_net uses macvtap, enable zero copy between |
413 | * guest kernel and host kernel when lower device supports zerocopy |
414 | * |
415 | * The macvlan supports zerocopy iff the lower device supports zero |
416 | * copy so we don't have to look at the lower device directly. |
417 | */ |
418 | if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) |
419 | sock_set_flag(&q->sk, SOCK_ZEROCOPY); |
420 | |
421 | err = macvtap_set_queue(dev, file, q); |
422 | if (err) |
423 | sock_put(&q->sk); |
424 | |
425 | out: |
426 | if (dev) |
427 | dev_put(dev); |
428 | |
429 | return err; |
430 | } |
431 | |
432 | static int macvtap_release(struct inode *inode, struct file *file) |
433 | { |
434 | struct macvtap_queue *q = file->private_data; |
435 | macvtap_put_queue(q); |
436 | return 0; |
437 | } |
438 | |
439 | static unsigned int macvtap_poll(struct file *file, poll_table * wait) |
440 | { |
441 | struct macvtap_queue *q = file->private_data; |
442 | unsigned int mask = POLLERR; |
443 | |
444 | if (!q) |
445 | goto out; |
446 | |
447 | mask = 0; |
448 | poll_wait(file, &q->wq.wait, wait); |
449 | |
450 | if (!skb_queue_empty(&q->sk.sk_receive_queue)) |
451 | mask |= POLLIN | POLLRDNORM; |
452 | |
453 | if (sock_writeable(&q->sk) || |
454 | (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && |
455 | sock_writeable(&q->sk))) |
456 | mask |= POLLOUT | POLLWRNORM; |
457 | |
458 | out: |
459 | return mask; |
460 | } |
461 | |
462 | static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, |
463 | size_t len, size_t linear, |
464 | int noblock, int *err) |
465 | { |
466 | struct sk_buff *skb; |
467 | |
468 | /* Under a page? Don't bother with paged skb. */ |
469 | if (prepad + len < PAGE_SIZE || !linear) |
470 | linear = len; |
471 | |
472 | skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, |
473 | err); |
474 | if (!skb) |
475 | return NULL; |
476 | |
477 | skb_reserve(skb, prepad); |
478 | skb_put(skb, linear); |
479 | skb->data_len = len - linear; |
480 | skb->len += len - linear; |
481 | |
482 | return skb; |
483 | } |
484 | |
485 | /* set skb frags from iovec, this can move to core network code for reuse */ |
486 | static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, |
487 | int offset, size_t count) |
488 | { |
489 | int len = iov_length(from, count) - offset; |
490 | int copy = skb_headlen(skb); |
491 | int size, offset1 = 0; |
492 | int i = 0; |
493 | |
494 | /* Skip over from offset */ |
495 | while (count && (offset >= from->iov_len)) { |
496 | offset -= from->iov_len; |
497 | ++from; |
498 | --count; |
499 | } |
500 | |
501 | /* copy up to skb headlen */ |
502 | while (count && (copy > 0)) { |
503 | size = min_t(unsigned int, copy, from->iov_len - offset); |
504 | if (copy_from_user(skb->data + offset1, from->iov_base + offset, |
505 | size)) |
506 | return -EFAULT; |
507 | if (copy > size) { |
508 | ++from; |
509 | --count; |
510 | offset = 0; |
511 | } else |
512 | offset += size; |
513 | copy -= size; |
514 | offset1 += size; |
515 | } |
516 | |
517 | if (len == offset1) |
518 | return 0; |
519 | |
520 | while (count--) { |
521 | struct page *page[MAX_SKB_FRAGS]; |
522 | int num_pages; |
523 | unsigned long base; |
524 | unsigned long truesize; |
525 | |
526 | len = from->iov_len - offset; |
527 | if (!len) { |
528 | offset = 0; |
529 | ++from; |
530 | continue; |
531 | } |
532 | base = (unsigned long)from->iov_base + offset; |
533 | size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; |
534 | if (i + size > MAX_SKB_FRAGS) |
535 | return -EMSGSIZE; |
536 | num_pages = get_user_pages_fast(base, size, 0, &page[i]); |
537 | if (num_pages != size) { |
538 | for (i = 0; i < num_pages; i++) |
539 | put_page(page[i]); |
540 | return -EFAULT; |
541 | } |
542 | truesize = size * PAGE_SIZE; |
543 | skb->data_len += len; |
544 | skb->len += len; |
545 | skb->truesize += truesize; |
546 | atomic_add(truesize, &skb->sk->sk_wmem_alloc); |
547 | while (len) { |
548 | int off = base & ~PAGE_MASK; |
549 | int size = min_t(int, len, PAGE_SIZE - off); |
550 | __skb_fill_page_desc(skb, i, page[i], off, size); |
551 | skb_shinfo(skb)->nr_frags++; |
552 | /* increase sk_wmem_alloc */ |
553 | base += size; |
554 | len -= size; |
555 | i++; |
556 | } |
557 | offset = 0; |
558 | ++from; |
559 | } |
560 | return 0; |
561 | } |
562 | |
563 | /* |
564 | * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should |
565 | * be shared with the tun/tap driver. |
566 | */ |
567 | static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, |
568 | struct virtio_net_hdr *vnet_hdr) |
569 | { |
570 | unsigned short gso_type = 0; |
571 | if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |
572 | switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { |
573 | case VIRTIO_NET_HDR_GSO_TCPV4: |
574 | gso_type = SKB_GSO_TCPV4; |
575 | break; |
576 | case VIRTIO_NET_HDR_GSO_TCPV6: |
577 | gso_type = SKB_GSO_TCPV6; |
578 | break; |
579 | case VIRTIO_NET_HDR_GSO_UDP: |
580 | gso_type = SKB_GSO_UDP; |
581 | break; |
582 | default: |
583 | return -EINVAL; |
584 | } |
585 | |
586 | if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) |
587 | gso_type |= SKB_GSO_TCP_ECN; |
588 | |
589 | if (vnet_hdr->gso_size == 0) |
590 | return -EINVAL; |
591 | } |
592 | |
593 | if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { |
594 | if (!skb_partial_csum_set(skb, vnet_hdr->csum_start, |
595 | vnet_hdr->csum_offset)) |
596 | return -EINVAL; |
597 | } |
598 | |
599 | if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |
600 | skb_shinfo(skb)->gso_size = vnet_hdr->gso_size; |
601 | skb_shinfo(skb)->gso_type = gso_type; |
602 | |
603 | /* Header must be checked, and gso_segs computed. */ |
604 | skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; |
605 | skb_shinfo(skb)->gso_segs = 0; |
606 | } |
607 | return 0; |
608 | } |
609 | |
610 | static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, |
611 | struct virtio_net_hdr *vnet_hdr) |
612 | { |
613 | memset(vnet_hdr, 0, sizeof(*vnet_hdr)); |
614 | |
615 | if (skb_is_gso(skb)) { |
616 | struct skb_shared_info *sinfo = skb_shinfo(skb); |
617 | |
618 | /* This is a hint as to how much should be linear. */ |
619 | vnet_hdr->hdr_len = skb_headlen(skb); |
620 | vnet_hdr->gso_size = sinfo->gso_size; |
621 | if (sinfo->gso_type & SKB_GSO_TCPV4) |
622 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; |
623 | else if (sinfo->gso_type & SKB_GSO_TCPV6) |
624 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; |
625 | else if (sinfo->gso_type & SKB_GSO_UDP) |
626 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; |
627 | else |
628 | BUG(); |
629 | if (sinfo->gso_type & SKB_GSO_TCP_ECN) |
630 | vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; |
631 | } else |
632 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; |
633 | |
634 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
635 | vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; |
636 | vnet_hdr->csum_start = skb_checksum_start_offset(skb); |
637 | vnet_hdr->csum_offset = skb->csum_offset; |
638 | } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { |
639 | vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; |
640 | } /* else everything is zero */ |
641 | |
642 | return 0; |
643 | } |
644 | |
645 | |
646 | /* Get packet from user space buffer */ |
647 | static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, |
648 | const struct iovec *iv, unsigned long total_len, |
649 | size_t count, int noblock) |
650 | { |
651 | struct sk_buff *skb; |
652 | struct macvlan_dev *vlan; |
653 | unsigned long len = total_len; |
654 | int err; |
655 | struct virtio_net_hdr vnet_hdr = { 0 }; |
656 | int vnet_hdr_len = 0; |
657 | int copylen = 0; |
658 | bool zerocopy = false; |
659 | |
660 | if (q->flags & IFF_VNET_HDR) { |
661 | vnet_hdr_len = q->vnet_hdr_sz; |
662 | |
663 | err = -EINVAL; |
664 | if (len < vnet_hdr_len) |
665 | goto err; |
666 | len -= vnet_hdr_len; |
667 | |
668 | err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0, |
669 | sizeof(vnet_hdr)); |
670 | if (err < 0) |
671 | goto err; |
672 | if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && |
673 | vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 > |
674 | vnet_hdr.hdr_len) |
675 | vnet_hdr.hdr_len = vnet_hdr.csum_start + |
676 | vnet_hdr.csum_offset + 2; |
677 | err = -EINVAL; |
678 | if (vnet_hdr.hdr_len > len) |
679 | goto err; |
680 | } |
681 | |
682 | err = -EINVAL; |
683 | if (unlikely(len < ETH_HLEN)) |
684 | goto err; |
685 | |
686 | err = -EMSGSIZE; |
687 | if (unlikely(count > UIO_MAXIOV)) |
688 | goto err; |
689 | |
690 | if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) |
691 | zerocopy = true; |
692 | |
693 | if (zerocopy) { |
694 | /* Userspace may produce vectors with count greater than |
695 | * MAX_SKB_FRAGS, so we need to linearize parts of the skb |
696 | * to let the rest of data to be fit in the frags. |
697 | */ |
698 | if (count > MAX_SKB_FRAGS) { |
699 | copylen = iov_length(iv, count - MAX_SKB_FRAGS); |
700 | if (copylen < vnet_hdr_len) |
701 | copylen = 0; |
702 | else |
703 | copylen -= vnet_hdr_len; |
704 | } |
705 | /* There are 256 bytes to be copied in skb, so there is enough |
706 | * room for skb expand head in case it is used. |
707 | * The rest buffer is mapped from userspace. |
708 | */ |
709 | if (copylen < vnet_hdr.hdr_len) |
710 | copylen = vnet_hdr.hdr_len; |
711 | if (!copylen) |
712 | copylen = GOODCOPY_LEN; |
713 | } else |
714 | copylen = len; |
715 | |
716 | skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, |
717 | vnet_hdr.hdr_len, noblock, &err); |
718 | if (!skb) |
719 | goto err; |
720 | |
721 | if (zerocopy) |
722 | err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count); |
723 | else |
724 | err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, |
725 | len); |
726 | if (err) |
727 | goto err_kfree; |
728 | |
729 | skb_set_network_header(skb, ETH_HLEN); |
730 | skb_reset_mac_header(skb); |
731 | skb->protocol = eth_hdr(skb)->h_proto; |
732 | |
733 | if (vnet_hdr_len) { |
734 | err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr); |
735 | if (err) |
736 | goto err_kfree; |
737 | } |
738 | |
739 | rcu_read_lock_bh(); |
740 | vlan = rcu_dereference_bh(q->vlan); |
741 | /* copy skb_ubuf_info for callback when skb has no error */ |
742 | if (zerocopy) { |
743 | skb_shinfo(skb)->destructor_arg = m->msg_control; |
744 | skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; |
745 | } |
746 | if (vlan) |
747 | macvlan_start_xmit(skb, vlan->dev); |
748 | else |
749 | kfree_skb(skb); |
750 | rcu_read_unlock_bh(); |
751 | |
752 | return total_len; |
753 | |
754 | err_kfree: |
755 | kfree_skb(skb); |
756 | |
757 | err: |
758 | rcu_read_lock_bh(); |
759 | vlan = rcu_dereference_bh(q->vlan); |
760 | if (vlan) |
761 | vlan->dev->stats.tx_dropped++; |
762 | rcu_read_unlock_bh(); |
763 | |
764 | return err; |
765 | } |
766 | |
767 | static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv, |
768 | unsigned long count, loff_t pos) |
769 | { |
770 | struct file *file = iocb->ki_filp; |
771 | ssize_t result = -ENOLINK; |
772 | struct macvtap_queue *q = file->private_data; |
773 | |
774 | result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count, |
775 | file->f_flags & O_NONBLOCK); |
776 | return result; |
777 | } |
778 | |
779 | /* Put packet to the user space buffer */ |
780 | static ssize_t macvtap_put_user(struct macvtap_queue *q, |
781 | const struct sk_buff *skb, |
782 | const struct iovec *iv, int len) |
783 | { |
784 | struct macvlan_dev *vlan; |
785 | int ret; |
786 | int vnet_hdr_len = 0; |
787 | int vlan_offset = 0; |
788 | int copied; |
789 | |
790 | if (q->flags & IFF_VNET_HDR) { |
791 | struct virtio_net_hdr vnet_hdr; |
792 | vnet_hdr_len = q->vnet_hdr_sz; |
793 | if ((len -= vnet_hdr_len) < 0) |
794 | return -EINVAL; |
795 | |
796 | ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr); |
797 | if (ret) |
798 | return ret; |
799 | |
800 | if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) |
801 | return -EFAULT; |
802 | } |
803 | copied = vnet_hdr_len; |
804 | |
805 | if (!vlan_tx_tag_present(skb)) |
806 | len = min_t(int, skb->len, len); |
807 | else { |
808 | int copy; |
809 | struct { |
810 | __be16 h_vlan_proto; |
811 | __be16 h_vlan_TCI; |
812 | } veth; |
813 | veth.h_vlan_proto = htons(ETH_P_8021Q); |
814 | veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); |
815 | |
816 | vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); |
817 | len = min_t(int, skb->len + VLAN_HLEN, len); |
818 | |
819 | copy = min_t(int, vlan_offset, len); |
820 | ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); |
821 | len -= copy; |
822 | copied += copy; |
823 | if (ret || !len) |
824 | goto done; |
825 | |
826 | copy = min_t(int, sizeof(veth), len); |
827 | ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); |
828 | len -= copy; |
829 | copied += copy; |
830 | if (ret || !len) |
831 | goto done; |
832 | } |
833 | |
834 | ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); |
835 | copied += len; |
836 | |
837 | done: |
838 | rcu_read_lock_bh(); |
839 | vlan = rcu_dereference_bh(q->vlan); |
840 | if (vlan) |
841 | macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0); |
842 | rcu_read_unlock_bh(); |
843 | |
844 | return ret ? ret : copied; |
845 | } |
846 | |
847 | static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, |
848 | const struct iovec *iv, unsigned long len, |
849 | int noblock) |
850 | { |
851 | DEFINE_WAIT(wait); |
852 | struct sk_buff *skb; |
853 | ssize_t ret = 0; |
854 | |
855 | while (len) { |
856 | prepare_to_wait(sk_sleep(&q->sk), &wait, TASK_INTERRUPTIBLE); |
857 | |
858 | /* Read frames from the queue */ |
859 | skb = skb_dequeue(&q->sk.sk_receive_queue); |
860 | if (!skb) { |
861 | if (noblock) { |
862 | ret = -EAGAIN; |
863 | break; |
864 | } |
865 | if (signal_pending(current)) { |
866 | ret = -ERESTARTSYS; |
867 | break; |
868 | } |
869 | /* Nothing to read, let's sleep */ |
870 | schedule(); |
871 | continue; |
872 | } |
873 | ret = macvtap_put_user(q, skb, iv, len); |
874 | kfree_skb(skb); |
875 | break; |
876 | } |
877 | |
878 | finish_wait(sk_sleep(&q->sk), &wait); |
879 | return ret; |
880 | } |
881 | |
882 | static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, |
883 | unsigned long count, loff_t pos) |
884 | { |
885 | struct file *file = iocb->ki_filp; |
886 | struct macvtap_queue *q = file->private_data; |
887 | ssize_t len, ret = 0; |
888 | |
889 | len = iov_length(iv, count); |
890 | if (len < 0) { |
891 | ret = -EINVAL; |
892 | goto out; |
893 | } |
894 | |
895 | ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK); |
896 | ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */ |
897 | out: |
898 | return ret; |
899 | } |
900 | |
901 | /* |
902 | * provide compatibility with generic tun/tap interface |
903 | */ |
904 | static long macvtap_ioctl(struct file *file, unsigned int cmd, |
905 | unsigned long arg) |
906 | { |
907 | struct macvtap_queue *q = file->private_data; |
908 | struct macvlan_dev *vlan; |
909 | void __user *argp = (void __user *)arg; |
910 | struct ifreq __user *ifr = argp; |
911 | unsigned int __user *up = argp; |
912 | unsigned int u; |
913 | int __user *sp = argp; |
914 | int s; |
915 | int ret; |
916 | |
917 | switch (cmd) { |
918 | case TUNSETIFF: |
919 | /* ignore the name, just look at flags */ |
920 | if (get_user(u, &ifr->ifr_flags)) |
921 | return -EFAULT; |
922 | |
923 | ret = 0; |
924 | if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP)) |
925 | ret = -EINVAL; |
926 | else |
927 | q->flags = u; |
928 | |
929 | return ret; |
930 | |
931 | case TUNGETIFF: |
932 | rcu_read_lock_bh(); |
933 | vlan = rcu_dereference_bh(q->vlan); |
934 | if (vlan) |
935 | dev_hold(vlan->dev); |
936 | rcu_read_unlock_bh(); |
937 | |
938 | if (!vlan) |
939 | return -ENOLINK; |
940 | |
941 | ret = 0; |
942 | if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || |
943 | put_user(q->flags, &ifr->ifr_flags)) |
944 | ret = -EFAULT; |
945 | dev_put(vlan->dev); |
946 | return ret; |
947 | |
948 | case TUNGETFEATURES: |
949 | if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up)) |
950 | return -EFAULT; |
951 | return 0; |
952 | |
953 | case TUNSETSNDBUF: |
954 | if (get_user(u, up)) |
955 | return -EFAULT; |
956 | |
957 | q->sk.sk_sndbuf = u; |
958 | return 0; |
959 | |
960 | case TUNGETVNETHDRSZ: |
961 | s = q->vnet_hdr_sz; |
962 | if (put_user(s, sp)) |
963 | return -EFAULT; |
964 | return 0; |
965 | |
966 | case TUNSETVNETHDRSZ: |
967 | if (get_user(s, sp)) |
968 | return -EFAULT; |
969 | if (s < (int)sizeof(struct virtio_net_hdr)) |
970 | return -EINVAL; |
971 | |
972 | q->vnet_hdr_sz = s; |
973 | return 0; |
974 | |
975 | case TUNSETOFFLOAD: |
976 | /* let the user check for future flags */ |
977 | if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | |
978 | TUN_F_TSO_ECN | TUN_F_UFO)) |
979 | return -EINVAL; |
980 | |
981 | /* TODO: only accept frames with the features that |
982 | got enabled for forwarded frames */ |
983 | if (!(q->flags & IFF_VNET_HDR)) |
984 | return -EINVAL; |
985 | return 0; |
986 | |
987 | default: |
988 | return -EINVAL; |
989 | } |
990 | } |
991 | |
992 | #ifdef CONFIG_COMPAT |
993 | static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, |
994 | unsigned long arg) |
995 | { |
996 | return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); |
997 | } |
998 | #endif |
999 | |
1000 | static const struct file_operations macvtap_fops = { |
1001 | .owner = THIS_MODULE, |
1002 | .open = macvtap_open, |
1003 | .release = macvtap_release, |
1004 | .aio_read = macvtap_aio_read, |
1005 | .aio_write = macvtap_aio_write, |
1006 | .poll = macvtap_poll, |
1007 | .llseek = no_llseek, |
1008 | .unlocked_ioctl = macvtap_ioctl, |
1009 | #ifdef CONFIG_COMPAT |
1010 | .compat_ioctl = macvtap_compat_ioctl, |
1011 | #endif |
1012 | }; |
1013 | |
1014 | static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, |
1015 | struct msghdr *m, size_t total_len) |
1016 | { |
1017 | struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); |
1018 | return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen, |
1019 | m->msg_flags & MSG_DONTWAIT); |
1020 | } |
1021 | |
1022 | static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, |
1023 | struct msghdr *m, size_t total_len, |
1024 | int flags) |
1025 | { |
1026 | struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); |
1027 | int ret; |
1028 | if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) |
1029 | return -EINVAL; |
1030 | ret = macvtap_do_read(q, iocb, m->msg_iov, total_len, |
1031 | flags & MSG_DONTWAIT); |
1032 | if (ret > total_len) { |
1033 | m->msg_flags |= MSG_TRUNC; |
1034 | ret = flags & MSG_TRUNC ? ret : total_len; |
1035 | } |
1036 | return ret; |
1037 | } |
1038 | |
1039 | /* Ops structure to mimic raw sockets with tun */ |
1040 | static const struct proto_ops macvtap_socket_ops = { |
1041 | .sendmsg = macvtap_sendmsg, |
1042 | .recvmsg = macvtap_recvmsg, |
1043 | }; |
1044 | |
1045 | /* Get an underlying socket object from tun file. Returns error unless file is |
1046 | * attached to a device. The returned object works like a packet socket, it |
1047 | * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for |
1048 | * holding a reference to the file for as long as the socket is in use. */ |
1049 | struct socket *macvtap_get_socket(struct file *file) |
1050 | { |
1051 | struct macvtap_queue *q; |
1052 | if (file->f_op != &macvtap_fops) |
1053 | return ERR_PTR(-EINVAL); |
1054 | q = file->private_data; |
1055 | if (!q) |
1056 | return ERR_PTR(-EBADFD); |
1057 | return &q->sock; |
1058 | } |
1059 | EXPORT_SYMBOL_GPL(macvtap_get_socket); |
1060 | |
1061 | static int macvtap_device_event(struct notifier_block *unused, |
1062 | unsigned long event, void *ptr) |
1063 | { |
1064 | struct net_device *dev = ptr; |
1065 | struct macvlan_dev *vlan; |
1066 | struct device *classdev; |
1067 | dev_t devt; |
1068 | int err; |
1069 | |
1070 | if (dev->rtnl_link_ops != &macvtap_link_ops) |
1071 | return NOTIFY_DONE; |
1072 | |
1073 | vlan = netdev_priv(dev); |
1074 | |
1075 | switch (event) { |
1076 | case NETDEV_REGISTER: |
1077 | /* Create the device node here after the network device has |
1078 | * been registered but before register_netdevice has |
1079 | * finished running. |
1080 | */ |
1081 | err = macvtap_get_minor(vlan); |
1082 | if (err) |
1083 | return notifier_from_errno(err); |
1084 | |
1085 | devt = MKDEV(MAJOR(macvtap_major), vlan->minor); |
1086 | classdev = device_create(macvtap_class, &dev->dev, devt, |
1087 | dev, "tap%d", dev->ifindex); |
1088 | if (IS_ERR(classdev)) { |
1089 | macvtap_free_minor(vlan); |
1090 | return notifier_from_errno(PTR_ERR(classdev)); |
1091 | } |
1092 | break; |
1093 | case NETDEV_UNREGISTER: |
1094 | devt = MKDEV(MAJOR(macvtap_major), vlan->minor); |
1095 | device_destroy(macvtap_class, devt); |
1096 | macvtap_free_minor(vlan); |
1097 | break; |
1098 | } |
1099 | |
1100 | return NOTIFY_DONE; |
1101 | } |
1102 | |
1103 | static struct notifier_block macvtap_notifier_block __read_mostly = { |
1104 | .notifier_call = macvtap_device_event, |
1105 | }; |
1106 | |
1107 | static int macvtap_init(void) |
1108 | { |
1109 | int err; |
1110 | |
1111 | err = alloc_chrdev_region(&macvtap_major, 0, |
1112 | MACVTAP_NUM_DEVS, "macvtap"); |
1113 | if (err) |
1114 | goto out1; |
1115 | |
1116 | cdev_init(&macvtap_cdev, &macvtap_fops); |
1117 | err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); |
1118 | if (err) |
1119 | goto out2; |
1120 | |
1121 | macvtap_class = class_create(THIS_MODULE, "macvtap"); |
1122 | if (IS_ERR(macvtap_class)) { |
1123 | err = PTR_ERR(macvtap_class); |
1124 | goto out3; |
1125 | } |
1126 | |
1127 | err = register_netdevice_notifier(&macvtap_notifier_block); |
1128 | if (err) |
1129 | goto out4; |
1130 | |
1131 | err = macvlan_link_register(&macvtap_link_ops); |
1132 | if (err) |
1133 | goto out5; |
1134 | |
1135 | return 0; |
1136 | |
1137 | out5: |
1138 | unregister_netdevice_notifier(&macvtap_notifier_block); |
1139 | out4: |
1140 | class_unregister(macvtap_class); |
1141 | out3: |
1142 | cdev_del(&macvtap_cdev); |
1143 | out2: |
1144 | unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); |
1145 | out1: |
1146 | return err; |
1147 | } |
1148 | module_init(macvtap_init); |
1149 | |
1150 | static void macvtap_exit(void) |
1151 | { |
1152 | rtnl_link_unregister(&macvtap_link_ops); |
1153 | unregister_netdevice_notifier(&macvtap_notifier_block); |
1154 | class_unregister(macvtap_class); |
1155 | cdev_del(&macvtap_cdev); |
1156 | unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); |
1157 | } |
1158 | module_exit(macvtap_exit); |
1159 | |
1160 | MODULE_ALIAS_RTNL_LINK("macvtap"); |
1161 | MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); |
1162 | MODULE_LICENSE("GPL"); |
1163 |
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