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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 | |
283 | mutex_lock(&minor_lock); |
284 | retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); |
285 | if (retval >= 0) { |
286 | vlan->minor = retval; |
287 | } else if (retval == -ENOSPC) { |
288 | printk(KERN_ERR "too many macvtap devices\n"); |
289 | retval = -EINVAL; |
290 | } |
291 | mutex_unlock(&minor_lock); |
292 | return retval < 0 ? retval : 0; |
293 | } |
294 | |
295 | static void macvtap_free_minor(struct macvlan_dev *vlan) |
296 | { |
297 | mutex_lock(&minor_lock); |
298 | if (vlan->minor) { |
299 | idr_remove(&minor_idr, vlan->minor); |
300 | vlan->minor = 0; |
301 | } |
302 | mutex_unlock(&minor_lock); |
303 | } |
304 | |
305 | static struct net_device *dev_get_by_macvtap_minor(int minor) |
306 | { |
307 | struct net_device *dev = NULL; |
308 | struct macvlan_dev *vlan; |
309 | |
310 | mutex_lock(&minor_lock); |
311 | vlan = idr_find(&minor_idr, minor); |
312 | if (vlan) { |
313 | dev = vlan->dev; |
314 | dev_hold(dev); |
315 | } |
316 | mutex_unlock(&minor_lock); |
317 | return dev; |
318 | } |
319 | |
320 | static int macvtap_newlink(struct net *src_net, |
321 | struct net_device *dev, |
322 | struct nlattr *tb[], |
323 | struct nlattr *data[]) |
324 | { |
325 | /* Don't put anything that may fail after macvlan_common_newlink |
326 | * because we can't undo what it does. |
327 | */ |
328 | return macvlan_common_newlink(src_net, dev, tb, data, |
329 | macvtap_receive, macvtap_forward); |
330 | } |
331 | |
332 | static void macvtap_dellink(struct net_device *dev, |
333 | struct list_head *head) |
334 | { |
335 | macvtap_del_queues(dev); |
336 | macvlan_dellink(dev, head); |
337 | } |
338 | |
339 | static void macvtap_setup(struct net_device *dev) |
340 | { |
341 | macvlan_common_setup(dev); |
342 | dev->tx_queue_len = TUN_READQ_SIZE; |
343 | } |
344 | |
345 | static struct rtnl_link_ops macvtap_link_ops __read_mostly = { |
346 | .kind = "macvtap", |
347 | .setup = macvtap_setup, |
348 | .newlink = macvtap_newlink, |
349 | .dellink = macvtap_dellink, |
350 | }; |
351 | |
352 | |
353 | static void macvtap_sock_write_space(struct sock *sk) |
354 | { |
355 | wait_queue_head_t *wqueue; |
356 | |
357 | if (!sock_writeable(sk) || |
358 | !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) |
359 | return; |
360 | |
361 | wqueue = sk_sleep(sk); |
362 | if (wqueue && waitqueue_active(wqueue)) |
363 | wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); |
364 | } |
365 | |
366 | static void macvtap_sock_destruct(struct sock *sk) |
367 | { |
368 | skb_queue_purge(&sk->sk_receive_queue); |
369 | } |
370 | |
371 | static int macvtap_open(struct inode *inode, struct file *file) |
372 | { |
373 | struct net *net = current->nsproxy->net_ns; |
374 | struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode)); |
375 | struct macvtap_queue *q; |
376 | int err; |
377 | |
378 | err = -ENODEV; |
379 | if (!dev) |
380 | goto out; |
381 | |
382 | err = -ENOMEM; |
383 | q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, |
384 | &macvtap_proto); |
385 | if (!q) |
386 | goto out; |
387 | |
388 | q->sock.wq = &q->wq; |
389 | init_waitqueue_head(&q->wq.wait); |
390 | q->sock.type = SOCK_RAW; |
391 | q->sock.state = SS_CONNECTED; |
392 | q->sock.file = file; |
393 | q->sock.ops = &macvtap_socket_ops; |
394 | sock_init_data(&q->sock, &q->sk); |
395 | q->sk.sk_write_space = macvtap_sock_write_space; |
396 | q->sk.sk_destruct = macvtap_sock_destruct; |
397 | q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; |
398 | q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); |
399 | |
400 | /* |
401 | * so far only KVM virtio_net uses macvtap, enable zero copy between |
402 | * guest kernel and host kernel when lower device supports zerocopy |
403 | * |
404 | * The macvlan supports zerocopy iff the lower device supports zero |
405 | * copy so we don't have to look at the lower device directly. |
406 | */ |
407 | if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) |
408 | sock_set_flag(&q->sk, SOCK_ZEROCOPY); |
409 | |
410 | err = macvtap_set_queue(dev, file, q); |
411 | if (err) |
412 | sock_put(&q->sk); |
413 | |
414 | out: |
415 | if (dev) |
416 | dev_put(dev); |
417 | |
418 | return err; |
419 | } |
420 | |
421 | static int macvtap_release(struct inode *inode, struct file *file) |
422 | { |
423 | struct macvtap_queue *q = file->private_data; |
424 | macvtap_put_queue(q); |
425 | return 0; |
426 | } |
427 | |
428 | static unsigned int macvtap_poll(struct file *file, poll_table * wait) |
429 | { |
430 | struct macvtap_queue *q = file->private_data; |
431 | unsigned int mask = POLLERR; |
432 | |
433 | if (!q) |
434 | goto out; |
435 | |
436 | mask = 0; |
437 | poll_wait(file, &q->wq.wait, wait); |
438 | |
439 | if (!skb_queue_empty(&q->sk.sk_receive_queue)) |
440 | mask |= POLLIN | POLLRDNORM; |
441 | |
442 | if (sock_writeable(&q->sk) || |
443 | (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && |
444 | sock_writeable(&q->sk))) |
445 | mask |= POLLOUT | POLLWRNORM; |
446 | |
447 | out: |
448 | return mask; |
449 | } |
450 | |
451 | static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, |
452 | size_t len, size_t linear, |
453 | int noblock, int *err) |
454 | { |
455 | struct sk_buff *skb; |
456 | |
457 | /* Under a page? Don't bother with paged skb. */ |
458 | if (prepad + len < PAGE_SIZE || !linear) |
459 | linear = len; |
460 | |
461 | skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, |
462 | err); |
463 | if (!skb) |
464 | return NULL; |
465 | |
466 | skb_reserve(skb, prepad); |
467 | skb_put(skb, linear); |
468 | skb->data_len = len - linear; |
469 | skb->len += len - linear; |
470 | |
471 | return skb; |
472 | } |
473 | |
474 | /* set skb frags from iovec, this can move to core network code for reuse */ |
475 | static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, |
476 | int offset, size_t count) |
477 | { |
478 | int len = iov_length(from, count) - offset; |
479 | int copy = skb_headlen(skb); |
480 | int size, offset1 = 0; |
481 | int i = 0; |
482 | |
483 | /* Skip over from offset */ |
484 | while (count && (offset >= from->iov_len)) { |
485 | offset -= from->iov_len; |
486 | ++from; |
487 | --count; |
488 | } |
489 | |
490 | /* copy up to skb headlen */ |
491 | while (count && (copy > 0)) { |
492 | size = min_t(unsigned int, copy, from->iov_len - offset); |
493 | if (copy_from_user(skb->data + offset1, from->iov_base + offset, |
494 | size)) |
495 | return -EFAULT; |
496 | if (copy > size) { |
497 | ++from; |
498 | --count; |
499 | offset = 0; |
500 | } else |
501 | offset += size; |
502 | copy -= size; |
503 | offset1 += size; |
504 | } |
505 | |
506 | if (len == offset1) |
507 | return 0; |
508 | |
509 | while (count--) { |
510 | struct page *page[MAX_SKB_FRAGS]; |
511 | int num_pages; |
512 | unsigned long base; |
513 | unsigned long truesize; |
514 | |
515 | len = from->iov_len - offset; |
516 | if (!len) { |
517 | offset = 0; |
518 | ++from; |
519 | continue; |
520 | } |
521 | base = (unsigned long)from->iov_base + offset; |
522 | size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; |
523 | if (i + size > MAX_SKB_FRAGS) |
524 | return -EMSGSIZE; |
525 | num_pages = get_user_pages_fast(base, size, 0, &page[i]); |
526 | if (num_pages != size) { |
527 | for (i = 0; i < num_pages; i++) |
528 | put_page(page[i]); |
529 | return -EFAULT; |
530 | } |
531 | truesize = size * PAGE_SIZE; |
532 | skb->data_len += len; |
533 | skb->len += len; |
534 | skb->truesize += truesize; |
535 | atomic_add(truesize, &skb->sk->sk_wmem_alloc); |
536 | while (len) { |
537 | int off = base & ~PAGE_MASK; |
538 | int size = min_t(int, len, PAGE_SIZE - off); |
539 | __skb_fill_page_desc(skb, i, page[i], off, size); |
540 | skb_shinfo(skb)->nr_frags++; |
541 | /* increase sk_wmem_alloc */ |
542 | base += size; |
543 | len -= size; |
544 | i++; |
545 | } |
546 | offset = 0; |
547 | ++from; |
548 | } |
549 | return 0; |
550 | } |
551 | |
552 | /* |
553 | * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should |
554 | * be shared with the tun/tap driver. |
555 | */ |
556 | static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, |
557 | struct virtio_net_hdr *vnet_hdr) |
558 | { |
559 | unsigned short gso_type = 0; |
560 | if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |
561 | switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { |
562 | case VIRTIO_NET_HDR_GSO_TCPV4: |
563 | gso_type = SKB_GSO_TCPV4; |
564 | break; |
565 | case VIRTIO_NET_HDR_GSO_TCPV6: |
566 | gso_type = SKB_GSO_TCPV6; |
567 | break; |
568 | case VIRTIO_NET_HDR_GSO_UDP: |
569 | gso_type = SKB_GSO_UDP; |
570 | break; |
571 | default: |
572 | return -EINVAL; |
573 | } |
574 | |
575 | if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) |
576 | gso_type |= SKB_GSO_TCP_ECN; |
577 | |
578 | if (vnet_hdr->gso_size == 0) |
579 | return -EINVAL; |
580 | } |
581 | |
582 | if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { |
583 | if (!skb_partial_csum_set(skb, vnet_hdr->csum_start, |
584 | vnet_hdr->csum_offset)) |
585 | return -EINVAL; |
586 | } |
587 | |
588 | if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { |
589 | skb_shinfo(skb)->gso_size = vnet_hdr->gso_size; |
590 | skb_shinfo(skb)->gso_type = gso_type; |
591 | |
592 | /* Header must be checked, and gso_segs computed. */ |
593 | skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; |
594 | skb_shinfo(skb)->gso_segs = 0; |
595 | } |
596 | return 0; |
597 | } |
598 | |
599 | static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, |
600 | struct virtio_net_hdr *vnet_hdr) |
601 | { |
602 | memset(vnet_hdr, 0, sizeof(*vnet_hdr)); |
603 | |
604 | if (skb_is_gso(skb)) { |
605 | struct skb_shared_info *sinfo = skb_shinfo(skb); |
606 | |
607 | /* This is a hint as to how much should be linear. */ |
608 | vnet_hdr->hdr_len = skb_headlen(skb); |
609 | vnet_hdr->gso_size = sinfo->gso_size; |
610 | if (sinfo->gso_type & SKB_GSO_TCPV4) |
611 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; |
612 | else if (sinfo->gso_type & SKB_GSO_TCPV6) |
613 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; |
614 | else if (sinfo->gso_type & SKB_GSO_UDP) |
615 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; |
616 | else |
617 | BUG(); |
618 | if (sinfo->gso_type & SKB_GSO_TCP_ECN) |
619 | vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; |
620 | } else |
621 | vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; |
622 | |
623 | if (skb->ip_summed == CHECKSUM_PARTIAL) { |
624 | vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; |
625 | vnet_hdr->csum_start = skb_checksum_start_offset(skb); |
626 | vnet_hdr->csum_offset = skb->csum_offset; |
627 | } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { |
628 | vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; |
629 | } /* else everything is zero */ |
630 | |
631 | return 0; |
632 | } |
633 | |
634 | |
635 | /* Get packet from user space buffer */ |
636 | static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, |
637 | const struct iovec *iv, unsigned long total_len, |
638 | size_t count, int noblock) |
639 | { |
640 | struct sk_buff *skb; |
641 | struct macvlan_dev *vlan; |
642 | unsigned long len = total_len; |
643 | int err; |
644 | struct virtio_net_hdr vnet_hdr = { 0 }; |
645 | int vnet_hdr_len = 0; |
646 | int copylen = 0; |
647 | bool zerocopy = false; |
648 | |
649 | if (q->flags & IFF_VNET_HDR) { |
650 | vnet_hdr_len = q->vnet_hdr_sz; |
651 | |
652 | err = -EINVAL; |
653 | if (len < vnet_hdr_len) |
654 | goto err; |
655 | len -= vnet_hdr_len; |
656 | |
657 | err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0, |
658 | sizeof(vnet_hdr)); |
659 | if (err < 0) |
660 | goto err; |
661 | if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && |
662 | vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 > |
663 | vnet_hdr.hdr_len) |
664 | vnet_hdr.hdr_len = vnet_hdr.csum_start + |
665 | vnet_hdr.csum_offset + 2; |
666 | err = -EINVAL; |
667 | if (vnet_hdr.hdr_len > len) |
668 | goto err; |
669 | } |
670 | |
671 | err = -EINVAL; |
672 | if (unlikely(len < ETH_HLEN)) |
673 | goto err; |
674 | |
675 | err = -EMSGSIZE; |
676 | if (unlikely(count > UIO_MAXIOV)) |
677 | goto err; |
678 | |
679 | if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) |
680 | zerocopy = true; |
681 | |
682 | if (zerocopy) { |
683 | /* Userspace may produce vectors with count greater than |
684 | * MAX_SKB_FRAGS, so we need to linearize parts of the skb |
685 | * to let the rest of data to be fit in the frags. |
686 | */ |
687 | if (count > MAX_SKB_FRAGS) { |
688 | copylen = iov_length(iv, count - MAX_SKB_FRAGS); |
689 | if (copylen < vnet_hdr_len) |
690 | copylen = 0; |
691 | else |
692 | copylen -= vnet_hdr_len; |
693 | } |
694 | /* There are 256 bytes to be copied in skb, so there is enough |
695 | * room for skb expand head in case it is used. |
696 | * The rest buffer is mapped from userspace. |
697 | */ |
698 | if (copylen < vnet_hdr.hdr_len) |
699 | copylen = vnet_hdr.hdr_len; |
700 | if (!copylen) |
701 | copylen = GOODCOPY_LEN; |
702 | } else |
703 | copylen = len; |
704 | |
705 | skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, |
706 | vnet_hdr.hdr_len, noblock, &err); |
707 | if (!skb) |
708 | goto err; |
709 | |
710 | if (zerocopy) |
711 | err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count); |
712 | else |
713 | err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, |
714 | len); |
715 | if (err) |
716 | goto err_kfree; |
717 | |
718 | skb_set_network_header(skb, ETH_HLEN); |
719 | skb_reset_mac_header(skb); |
720 | skb->protocol = eth_hdr(skb)->h_proto; |
721 | |
722 | if (vnet_hdr_len) { |
723 | err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr); |
724 | if (err) |
725 | goto err_kfree; |
726 | } |
727 | |
728 | rcu_read_lock_bh(); |
729 | vlan = rcu_dereference_bh(q->vlan); |
730 | /* copy skb_ubuf_info for callback when skb has no error */ |
731 | if (zerocopy) { |
732 | skb_shinfo(skb)->destructor_arg = m->msg_control; |
733 | skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; |
734 | skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; |
735 | } |
736 | if (vlan) |
737 | macvlan_start_xmit(skb, vlan->dev); |
738 | else |
739 | kfree_skb(skb); |
740 | rcu_read_unlock_bh(); |
741 | |
742 | return total_len; |
743 | |
744 | err_kfree: |
745 | kfree_skb(skb); |
746 | |
747 | err: |
748 | rcu_read_lock_bh(); |
749 | vlan = rcu_dereference_bh(q->vlan); |
750 | if (vlan) |
751 | vlan->dev->stats.tx_dropped++; |
752 | rcu_read_unlock_bh(); |
753 | |
754 | return err; |
755 | } |
756 | |
757 | static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv, |
758 | unsigned long count, loff_t pos) |
759 | { |
760 | struct file *file = iocb->ki_filp; |
761 | ssize_t result = -ENOLINK; |
762 | struct macvtap_queue *q = file->private_data; |
763 | |
764 | result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count, |
765 | file->f_flags & O_NONBLOCK); |
766 | return result; |
767 | } |
768 | |
769 | /* Put packet to the user space buffer */ |
770 | static ssize_t macvtap_put_user(struct macvtap_queue *q, |
771 | const struct sk_buff *skb, |
772 | const struct iovec *iv, int len) |
773 | { |
774 | struct macvlan_dev *vlan; |
775 | int ret; |
776 | int vnet_hdr_len = 0; |
777 | int vlan_offset = 0; |
778 | int copied; |
779 | |
780 | if (q->flags & IFF_VNET_HDR) { |
781 | struct virtio_net_hdr vnet_hdr; |
782 | vnet_hdr_len = q->vnet_hdr_sz; |
783 | if ((len -= vnet_hdr_len) < 0) |
784 | return -EINVAL; |
785 | |
786 | ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr); |
787 | if (ret) |
788 | return ret; |
789 | |
790 | if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) |
791 | return -EFAULT; |
792 | } |
793 | copied = vnet_hdr_len; |
794 | |
795 | if (!vlan_tx_tag_present(skb)) |
796 | len = min_t(int, skb->len, len); |
797 | else { |
798 | int copy; |
799 | struct { |
800 | __be16 h_vlan_proto; |
801 | __be16 h_vlan_TCI; |
802 | } veth; |
803 | veth.h_vlan_proto = htons(ETH_P_8021Q); |
804 | veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); |
805 | |
806 | vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); |
807 | len = min_t(int, skb->len + VLAN_HLEN, len); |
808 | |
809 | copy = min_t(int, vlan_offset, len); |
810 | ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); |
811 | len -= copy; |
812 | copied += copy; |
813 | if (ret || !len) |
814 | goto done; |
815 | |
816 | copy = min_t(int, sizeof(veth), len); |
817 | ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); |
818 | len -= copy; |
819 | copied += copy; |
820 | if (ret || !len) |
821 | goto done; |
822 | } |
823 | |
824 | ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); |
825 | copied += len; |
826 | |
827 | done: |
828 | rcu_read_lock_bh(); |
829 | vlan = rcu_dereference_bh(q->vlan); |
830 | if (vlan) |
831 | macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0); |
832 | rcu_read_unlock_bh(); |
833 | |
834 | return ret ? ret : copied; |
835 | } |
836 | |
837 | static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, |
838 | const struct iovec *iv, unsigned long len, |
839 | int noblock) |
840 | { |
841 | DEFINE_WAIT(wait); |
842 | struct sk_buff *skb; |
843 | ssize_t ret = 0; |
844 | |
845 | while (len) { |
846 | prepare_to_wait(sk_sleep(&q->sk), &wait, TASK_INTERRUPTIBLE); |
847 | |
848 | /* Read frames from the queue */ |
849 | skb = skb_dequeue(&q->sk.sk_receive_queue); |
850 | if (!skb) { |
851 | if (noblock) { |
852 | ret = -EAGAIN; |
853 | break; |
854 | } |
855 | if (signal_pending(current)) { |
856 | ret = -ERESTARTSYS; |
857 | break; |
858 | } |
859 | /* Nothing to read, let's sleep */ |
860 | schedule(); |
861 | continue; |
862 | } |
863 | ret = macvtap_put_user(q, skb, iv, len); |
864 | kfree_skb(skb); |
865 | break; |
866 | } |
867 | |
868 | finish_wait(sk_sleep(&q->sk), &wait); |
869 | return ret; |
870 | } |
871 | |
872 | static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, |
873 | unsigned long count, loff_t pos) |
874 | { |
875 | struct file *file = iocb->ki_filp; |
876 | struct macvtap_queue *q = file->private_data; |
877 | ssize_t len, ret = 0; |
878 | |
879 | len = iov_length(iv, count); |
880 | if (len < 0) { |
881 | ret = -EINVAL; |
882 | goto out; |
883 | } |
884 | |
885 | ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK); |
886 | ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */ |
887 | out: |
888 | return ret; |
889 | } |
890 | |
891 | /* |
892 | * provide compatibility with generic tun/tap interface |
893 | */ |
894 | static long macvtap_ioctl(struct file *file, unsigned int cmd, |
895 | unsigned long arg) |
896 | { |
897 | struct macvtap_queue *q = file->private_data; |
898 | struct macvlan_dev *vlan; |
899 | void __user *argp = (void __user *)arg; |
900 | struct ifreq __user *ifr = argp; |
901 | unsigned int __user *up = argp; |
902 | unsigned int u; |
903 | int __user *sp = argp; |
904 | int s; |
905 | int ret; |
906 | |
907 | switch (cmd) { |
908 | case TUNSETIFF: |
909 | /* ignore the name, just look at flags */ |
910 | if (get_user(u, &ifr->ifr_flags)) |
911 | return -EFAULT; |
912 | |
913 | ret = 0; |
914 | if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP)) |
915 | ret = -EINVAL; |
916 | else |
917 | q->flags = u; |
918 | |
919 | return ret; |
920 | |
921 | case TUNGETIFF: |
922 | rcu_read_lock_bh(); |
923 | vlan = rcu_dereference_bh(q->vlan); |
924 | if (vlan) |
925 | dev_hold(vlan->dev); |
926 | rcu_read_unlock_bh(); |
927 | |
928 | if (!vlan) |
929 | return -ENOLINK; |
930 | |
931 | ret = 0; |
932 | if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || |
933 | put_user(q->flags, &ifr->ifr_flags)) |
934 | ret = -EFAULT; |
935 | dev_put(vlan->dev); |
936 | return ret; |
937 | |
938 | case TUNGETFEATURES: |
939 | if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up)) |
940 | return -EFAULT; |
941 | return 0; |
942 | |
943 | case TUNSETSNDBUF: |
944 | if (get_user(u, up)) |
945 | return -EFAULT; |
946 | |
947 | q->sk.sk_sndbuf = u; |
948 | return 0; |
949 | |
950 | case TUNGETVNETHDRSZ: |
951 | s = q->vnet_hdr_sz; |
952 | if (put_user(s, sp)) |
953 | return -EFAULT; |
954 | return 0; |
955 | |
956 | case TUNSETVNETHDRSZ: |
957 | if (get_user(s, sp)) |
958 | return -EFAULT; |
959 | if (s < (int)sizeof(struct virtio_net_hdr)) |
960 | return -EINVAL; |
961 | |
962 | q->vnet_hdr_sz = s; |
963 | return 0; |
964 | |
965 | case TUNSETOFFLOAD: |
966 | /* let the user check for future flags */ |
967 | if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | |
968 | TUN_F_TSO_ECN | TUN_F_UFO)) |
969 | return -EINVAL; |
970 | |
971 | /* TODO: only accept frames with the features that |
972 | got enabled for forwarded frames */ |
973 | if (!(q->flags & IFF_VNET_HDR)) |
974 | return -EINVAL; |
975 | return 0; |
976 | |
977 | default: |
978 | return -EINVAL; |
979 | } |
980 | } |
981 | |
982 | #ifdef CONFIG_COMPAT |
983 | static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, |
984 | unsigned long arg) |
985 | { |
986 | return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); |
987 | } |
988 | #endif |
989 | |
990 | static const struct file_operations macvtap_fops = { |
991 | .owner = THIS_MODULE, |
992 | .open = macvtap_open, |
993 | .release = macvtap_release, |
994 | .aio_read = macvtap_aio_read, |
995 | .aio_write = macvtap_aio_write, |
996 | .poll = macvtap_poll, |
997 | .llseek = no_llseek, |
998 | .unlocked_ioctl = macvtap_ioctl, |
999 | #ifdef CONFIG_COMPAT |
1000 | .compat_ioctl = macvtap_compat_ioctl, |
1001 | #endif |
1002 | }; |
1003 | |
1004 | static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, |
1005 | struct msghdr *m, size_t total_len) |
1006 | { |
1007 | struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); |
1008 | return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen, |
1009 | m->msg_flags & MSG_DONTWAIT); |
1010 | } |
1011 | |
1012 | static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, |
1013 | struct msghdr *m, size_t total_len, |
1014 | int flags) |
1015 | { |
1016 | struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); |
1017 | int ret; |
1018 | if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) |
1019 | return -EINVAL; |
1020 | ret = macvtap_do_read(q, iocb, m->msg_iov, total_len, |
1021 | flags & MSG_DONTWAIT); |
1022 | if (ret > total_len) { |
1023 | m->msg_flags |= MSG_TRUNC; |
1024 | ret = flags & MSG_TRUNC ? ret : total_len; |
1025 | } |
1026 | return ret; |
1027 | } |
1028 | |
1029 | /* Ops structure to mimic raw sockets with tun */ |
1030 | static const struct proto_ops macvtap_socket_ops = { |
1031 | .sendmsg = macvtap_sendmsg, |
1032 | .recvmsg = macvtap_recvmsg, |
1033 | }; |
1034 | |
1035 | /* Get an underlying socket object from tun file. Returns error unless file is |
1036 | * attached to a device. The returned object works like a packet socket, it |
1037 | * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for |
1038 | * holding a reference to the file for as long as the socket is in use. */ |
1039 | struct socket *macvtap_get_socket(struct file *file) |
1040 | { |
1041 | struct macvtap_queue *q; |
1042 | if (file->f_op != &macvtap_fops) |
1043 | return ERR_PTR(-EINVAL); |
1044 | q = file->private_data; |
1045 | if (!q) |
1046 | return ERR_PTR(-EBADFD); |
1047 | return &q->sock; |
1048 | } |
1049 | EXPORT_SYMBOL_GPL(macvtap_get_socket); |
1050 | |
1051 | static int macvtap_device_event(struct notifier_block *unused, |
1052 | unsigned long event, void *ptr) |
1053 | { |
1054 | struct net_device *dev = ptr; |
1055 | struct macvlan_dev *vlan; |
1056 | struct device *classdev; |
1057 | dev_t devt; |
1058 | int err; |
1059 | |
1060 | if (dev->rtnl_link_ops != &macvtap_link_ops) |
1061 | return NOTIFY_DONE; |
1062 | |
1063 | vlan = netdev_priv(dev); |
1064 | |
1065 | switch (event) { |
1066 | case NETDEV_REGISTER: |
1067 | /* Create the device node here after the network device has |
1068 | * been registered but before register_netdevice has |
1069 | * finished running. |
1070 | */ |
1071 | err = macvtap_get_minor(vlan); |
1072 | if (err) |
1073 | return notifier_from_errno(err); |
1074 | |
1075 | devt = MKDEV(MAJOR(macvtap_major), vlan->minor); |
1076 | classdev = device_create(macvtap_class, &dev->dev, devt, |
1077 | dev, "tap%d", dev->ifindex); |
1078 | if (IS_ERR(classdev)) { |
1079 | macvtap_free_minor(vlan); |
1080 | return notifier_from_errno(PTR_ERR(classdev)); |
1081 | } |
1082 | break; |
1083 | case NETDEV_UNREGISTER: |
1084 | devt = MKDEV(MAJOR(macvtap_major), vlan->minor); |
1085 | device_destroy(macvtap_class, devt); |
1086 | macvtap_free_minor(vlan); |
1087 | break; |
1088 | } |
1089 | |
1090 | return NOTIFY_DONE; |
1091 | } |
1092 | |
1093 | static struct notifier_block macvtap_notifier_block __read_mostly = { |
1094 | .notifier_call = macvtap_device_event, |
1095 | }; |
1096 | |
1097 | static int macvtap_init(void) |
1098 | { |
1099 | int err; |
1100 | |
1101 | err = alloc_chrdev_region(&macvtap_major, 0, |
1102 | MACVTAP_NUM_DEVS, "macvtap"); |
1103 | if (err) |
1104 | goto out1; |
1105 | |
1106 | cdev_init(&macvtap_cdev, &macvtap_fops); |
1107 | err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); |
1108 | if (err) |
1109 | goto out2; |
1110 | |
1111 | macvtap_class = class_create(THIS_MODULE, "macvtap"); |
1112 | if (IS_ERR(macvtap_class)) { |
1113 | err = PTR_ERR(macvtap_class); |
1114 | goto out3; |
1115 | } |
1116 | |
1117 | err = register_netdevice_notifier(&macvtap_notifier_block); |
1118 | if (err) |
1119 | goto out4; |
1120 | |
1121 | err = macvlan_link_register(&macvtap_link_ops); |
1122 | if (err) |
1123 | goto out5; |
1124 | |
1125 | return 0; |
1126 | |
1127 | out5: |
1128 | unregister_netdevice_notifier(&macvtap_notifier_block); |
1129 | out4: |
1130 | class_unregister(macvtap_class); |
1131 | out3: |
1132 | cdev_del(&macvtap_cdev); |
1133 | out2: |
1134 | unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); |
1135 | out1: |
1136 | return err; |
1137 | } |
1138 | module_init(macvtap_init); |
1139 | |
1140 | static void macvtap_exit(void) |
1141 | { |
1142 | rtnl_link_unregister(&macvtap_link_ops); |
1143 | unregister_netdevice_notifier(&macvtap_notifier_block); |
1144 | class_unregister(macvtap_class); |
1145 | cdev_del(&macvtap_cdev); |
1146 | unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); |
1147 | } |
1148 | module_exit(macvtap_exit); |
1149 | |
1150 | MODULE_ALIAS_RTNL_LINK("macvtap"); |
1151 | MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); |
1152 | MODULE_LICENSE("GPL"); |
1153 |
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