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powerpc/powernv: Report size of OPAL memcons log
[linux/fpc-iii.git] / drivers / net / macvtap.c
blob5c26653eceb5660c0cd12b1a6669a58525fe7207
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 netdev_err(vlan->dev, "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 err = macvlan_common_newlink(src_net, dev, tb, data);
495 if (err) {
496 netdev_rx_handler_unregister(dev);
497 return err;
498 }
499
500 return 0;
501 }
502
503 static void macvtap_dellink(struct net_device *dev,
504 struct list_head *head)
505 {
506 netdev_rx_handler_unregister(dev);
507 macvtap_del_queues(dev);
508 macvlan_dellink(dev, head);
509 }
510
511 static void macvtap_setup(struct net_device *dev)
512 {
513 macvlan_common_setup(dev);
514 dev->tx_queue_len = TUN_READQ_SIZE;
515 }
516
517 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
518 .kind = "macvtap",
519 .setup = macvtap_setup,
520 .newlink = macvtap_newlink,
521 .dellink = macvtap_dellink,
522 };
523
524
525 static void macvtap_sock_write_space(struct sock *sk)
526 {
527 wait_queue_head_t *wqueue;
528
529 if (!sock_writeable(sk) ||
530 !test_and_clear_bit(SOCKWQ_ASYNC_NOSPACE, &sk->sk_socket->flags))
531 return;
532
533 wqueue = sk_sleep(sk);
534 if (wqueue && waitqueue_active(wqueue))
535 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
536 }
537
538 static void macvtap_sock_destruct(struct sock *sk)
539 {
540 struct macvtap_queue *q = container_of(sk, struct macvtap_queue, sk);
541
542 skb_array_cleanup(&q->skb_array);
543 }
544
545 static int macvtap_open(struct inode *inode, struct file *file)
546 {
547 struct net *net = current->nsproxy->net_ns;
548 struct net_device *dev;
549 struct macvtap_queue *q;
550 int err = -ENODEV;
551
552 rtnl_lock();
553 dev = dev_get_by_macvtap_minor(iminor(inode));
554 if (!dev)
555 goto err;
556
557 err = -ENOMEM;
558 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
559 &macvtap_proto, 0);
560 if (!q)
561 goto err;
562
563 RCU_INIT_POINTER(q->sock.wq, &q->wq);
564 init_waitqueue_head(&q->wq.wait);
565 q->sock.type = SOCK_RAW;
566 q->sock.state = SS_CONNECTED;
567 q->sock.file = file;
568 q->sock.ops = &macvtap_socket_ops;
569 sock_init_data(&q->sock, &q->sk);
570 q->sk.sk_write_space = macvtap_sock_write_space;
571 q->sk.sk_destruct = macvtap_sock_destruct;
572 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
573 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
574
575 /*
576 * so far only KVM virtio_net uses macvtap, enable zero copy between
577 * guest kernel and host kernel when lower device supports zerocopy
578 *
579 * The macvlan supports zerocopy iff the lower device supports zero
580 * copy so we don't have to look at the lower device directly.
581 */
582 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
583 sock_set_flag(&q->sk, SOCK_ZEROCOPY);
584
585 err = -ENOMEM;
586 if (skb_array_init(&q->skb_array, dev->tx_queue_len, GFP_KERNEL))
587 goto err_array;
588
589 err = macvtap_set_queue(dev, file, q);
590 if (err)
591 goto err_queue;
592
593 dev_put(dev);
594
595 rtnl_unlock();
596 return err;
597
598 err_queue:
599 skb_array_cleanup(&q->skb_array);
600 err_array:
601 sock_put(&q->sk);
602 err:
603 if (dev)
604 dev_put(dev);
605
606 rtnl_unlock();
607 return err;
608 }
609
610 static int macvtap_release(struct inode *inode, struct file *file)
611 {
612 struct macvtap_queue *q = file->private_data;
613 macvtap_put_queue(q);
614 return 0;
615 }
616
617 static unsigned int macvtap_poll(struct file *file, poll_table * wait)
618 {
619 struct macvtap_queue *q = file->private_data;
620 unsigned int mask = POLLERR;
621
622 if (!q)
623 goto out;
624
625 mask = 0;
626 poll_wait(file, &q->wq.wait, wait);
627
628 if (!skb_array_empty(&q->skb_array))
629 mask |= POLLIN | POLLRDNORM;
630
631 if (sock_writeable(&q->sk) ||
632 (!test_and_set_bit(SOCKWQ_ASYNC_NOSPACE, &q->sock.flags) &&
633 sock_writeable(&q->sk)))
634 mask |= POLLOUT | POLLWRNORM;
635
636 out:
637 return mask;
638 }
639
640 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
641 size_t len, size_t linear,
642 int noblock, int *err)
643 {
644 struct sk_buff *skb;
645
646 /* Under a page? Don't bother with paged skb. */
647 if (prepad + len < PAGE_SIZE || !linear)
648 linear = len;
649
650 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
651 err, 0);
652 if (!skb)
653 return NULL;
654
655 skb_reserve(skb, prepad);
656 skb_put(skb, linear);
657 skb->data_len = len - linear;
658 skb->len += len - linear;
659
660 return skb;
661 }
662
663 /* Neighbour code has some assumptions on HH_DATA_MOD alignment */
664 #define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN)
665
666 /* Get packet from user space buffer */
667 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
668 struct iov_iter *from, int noblock)
669 {
670 int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE);
671 struct sk_buff *skb;
672 struct macvlan_dev *vlan;
673 unsigned long total_len = iov_iter_count(from);
674 unsigned long len = total_len;
675 int err;
676 struct virtio_net_hdr vnet_hdr = { 0 };
677 int vnet_hdr_len = 0;
678 int copylen = 0;
679 int depth;
680 bool zerocopy = false;
681 size_t linear;
682
683 if (q->flags & IFF_VNET_HDR) {
684 vnet_hdr_len = q->vnet_hdr_sz;
685
686 err = -EINVAL;
687 if (len < vnet_hdr_len)
688 goto err;
689 len -= vnet_hdr_len;
690
691 err = -EFAULT;
692 if (!copy_from_iter_full(&vnet_hdr, sizeof(vnet_hdr), from))
693 goto err;
694 iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr));
695 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
696 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
697 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 >
698 macvtap16_to_cpu(q, vnet_hdr.hdr_len))
699 vnet_hdr.hdr_len = cpu_to_macvtap16(q,
700 macvtap16_to_cpu(q, vnet_hdr.csum_start) +
701 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2);
702 err = -EINVAL;
703 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len)
704 goto err;
705 }
706
707 err = -EINVAL;
708 if (unlikely(len < ETH_HLEN))
709 goto err;
710
711 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) {
712 struct iov_iter i;
713
714 copylen = vnet_hdr.hdr_len ?
715 macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN;
716 if (copylen > good_linear)
717 copylen = good_linear;
718 else if (copylen < ETH_HLEN)
719 copylen = ETH_HLEN;
720 linear = copylen;
721 i = *from;
722 iov_iter_advance(&i, copylen);
723 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS)
724 zerocopy = true;
725 }
726
727 if (!zerocopy) {
728 copylen = len;
729 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len);
730 if (linear > good_linear)
731 linear = good_linear;
732 else if (linear < ETH_HLEN)
733 linear = ETH_HLEN;
734 }
735
736 skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen,
737 linear, noblock, &err);
738 if (!skb)
739 goto err;
740
741 if (zerocopy)
742 err = zerocopy_sg_from_iter(skb, from);
743 else
744 err = skb_copy_datagram_from_iter(skb, 0, from, len);
745
746 if (err)
747 goto err_kfree;
748
749 skb_set_network_header(skb, ETH_HLEN);
750 skb_reset_mac_header(skb);
751 skb->protocol = eth_hdr(skb)->h_proto;
752
753 if (vnet_hdr_len) {
754 err = virtio_net_hdr_to_skb(skb, &vnet_hdr,
755 macvtap_is_little_endian(q));
756 if (err)
757 goto err_kfree;
758 }
759
760 skb_probe_transport_header(skb, ETH_HLEN);
761
762 /* Move network header to the right position for VLAN tagged packets */
763 if ((skb->protocol == htons(ETH_P_8021Q) ||
764 skb->protocol == htons(ETH_P_8021AD)) &&
765 __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
766 skb_set_network_header(skb, depth);
767
768 rcu_read_lock();
769 vlan = rcu_dereference(q->vlan);
770 /* copy skb_ubuf_info for callback when skb has no error */
771 if (zerocopy) {
772 skb_shinfo(skb)->destructor_arg = m->msg_control;
773 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
774 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG;
775 } else if (m && m->msg_control) {
776 struct ubuf_info *uarg = m->msg_control;
777 uarg->callback(uarg, false);
778 }
779
780 if (vlan) {
781 skb->dev = vlan->dev;
782 dev_queue_xmit(skb);
783 } else {
784 kfree_skb(skb);
785 }
786 rcu_read_unlock();
787
788 return total_len;
789
790 err_kfree:
791 kfree_skb(skb);
792
793 err:
794 rcu_read_lock();
795 vlan = rcu_dereference(q->vlan);
796 if (vlan)
797 this_cpu_inc(vlan->pcpu_stats->tx_dropped);
798 rcu_read_unlock();
799
800 return err;
801 }
802
803 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from)
804 {
805 struct file *file = iocb->ki_filp;
806 struct macvtap_queue *q = file->private_data;
807
808 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK);
809 }
810
811 /* Put packet to the user space buffer */
812 static ssize_t macvtap_put_user(struct macvtap_queue *q,
813 const struct sk_buff *skb,
814 struct iov_iter *iter)
815 {
816 int ret;
817 int vnet_hdr_len = 0;
818 int vlan_offset = 0;
819 int total;
820
821 if (q->flags & IFF_VNET_HDR) {
822 struct virtio_net_hdr vnet_hdr;
823 vnet_hdr_len = q->vnet_hdr_sz;
824 if (iov_iter_count(iter) < vnet_hdr_len)
825 return -EINVAL;
826
827 if (virtio_net_hdr_from_skb(skb, &vnet_hdr,
828 macvtap_is_little_endian(q)))
829 BUG();
830
831 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) !=
832 sizeof(vnet_hdr))
833 return -EFAULT;
834
835 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr));
836 }
837 total = vnet_hdr_len;
838 total += skb->len;
839
840 if (skb_vlan_tag_present(skb)) {
841 struct {
842 __be16 h_vlan_proto;
843 __be16 h_vlan_TCI;
844 } veth;
845 veth.h_vlan_proto = skb->vlan_proto;
846 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb));
847
848 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
849 total += VLAN_HLEN;
850
851 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset);
852 if (ret || !iov_iter_count(iter))
853 goto done;
854
855 ret = copy_to_iter(&veth, sizeof(veth), iter);
856 if (ret != sizeof(veth) || !iov_iter_count(iter))
857 goto done;
858 }
859
860 ret = skb_copy_datagram_iter(skb, vlan_offset, iter,
861 skb->len - vlan_offset);
862
863 done:
864 return ret ? ret : total;
865 }
866
867 static ssize_t macvtap_do_read(struct macvtap_queue *q,
868 struct iov_iter *to,
869 int noblock)
870 {
871 DEFINE_WAIT(wait);
872 struct sk_buff *skb;
873 ssize_t ret = 0;
874
875 if (!iov_iter_count(to))
876 return 0;
877
878 while (1) {
879 if (!noblock)
880 prepare_to_wait(sk_sleep(&q->sk), &wait,
881 TASK_INTERRUPTIBLE);
882
883 /* Read frames from the queue */
884 skb = skb_array_consume(&q->skb_array);
885 if (skb)
886 break;
887 if (noblock) {
888 ret = -EAGAIN;
889 break;
890 }
891 if (signal_pending(current)) {
892 ret = -ERESTARTSYS;
893 break;
894 }
895 /* Nothing to read, let's sleep */
896 schedule();
897 }
898 if (!noblock)
899 finish_wait(sk_sleep(&q->sk), &wait);
900
901 if (skb) {
902 ret = macvtap_put_user(q, skb, to);
903 if (unlikely(ret < 0))
904 kfree_skb(skb);
905 else
906 consume_skb(skb);
907 }
908 return ret;
909 }
910
911 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to)
912 {
913 struct file *file = iocb->ki_filp;
914 struct macvtap_queue *q = file->private_data;
915 ssize_t len = iov_iter_count(to), ret;
916
917 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK);
918 ret = min_t(ssize_t, ret, len);
919 if (ret > 0)
920 iocb->ki_pos = ret;
921 return ret;
922 }
923
924 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q)
925 {
926 struct macvlan_dev *vlan;
927
928 ASSERT_RTNL();
929 vlan = rtnl_dereference(q->vlan);
930 if (vlan)
931 dev_hold(vlan->dev);
932
933 return vlan;
934 }
935
936 static void macvtap_put_vlan(struct macvlan_dev *vlan)
937 {
938 dev_put(vlan->dev);
939 }
940
941 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
942 {
943 struct macvtap_queue *q = file->private_data;
944 struct macvlan_dev *vlan;
945 int ret;
946
947 vlan = macvtap_get_vlan(q);
948 if (!vlan)
949 return -EINVAL;
950
951 if (flags & IFF_ATTACH_QUEUE)
952 ret = macvtap_enable_queue(vlan->dev, file, q);
953 else if (flags & IFF_DETACH_QUEUE)
954 ret = macvtap_disable_queue(q);
955 else
956 ret = -EINVAL;
957
958 macvtap_put_vlan(vlan);
959 return ret;
960 }
961
962 static int set_offload(struct macvtap_queue *q, unsigned long arg)
963 {
964 struct macvlan_dev *vlan;
965 netdev_features_t features;
966 netdev_features_t feature_mask = 0;
967
968 vlan = rtnl_dereference(q->vlan);
969 if (!vlan)
970 return -ENOLINK;
971
972 features = vlan->dev->features;
973
974 if (arg & TUN_F_CSUM) {
975 feature_mask = NETIF_F_HW_CSUM;
976
977 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) {
978 if (arg & TUN_F_TSO_ECN)
979 feature_mask |= NETIF_F_TSO_ECN;
980 if (arg & TUN_F_TSO4)
981 feature_mask |= NETIF_F_TSO;
982 if (arg & TUN_F_TSO6)
983 feature_mask |= NETIF_F_TSO6;
984 }
985
986 if (arg & TUN_F_UFO)
987 feature_mask |= NETIF_F_UFO;
988 }
989
990 /* tun/tap driver inverts the usage for TSO offloads, where
991 * setting the TSO bit means that the userspace wants to
992 * accept TSO frames and turning it off means that user space
993 * does not support TSO.
994 * For macvtap, we have to invert it to mean the same thing.
995 * When user space turns off TSO, we turn off GSO/LRO so that
996 * user-space will not receive TSO frames.
997 */
998 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO))
999 features |= RX_OFFLOADS;
1000 else
1001 features &= ~RX_OFFLOADS;
1002
1003 /* tap_features are the same as features on tun/tap and
1004 * reflect user expectations.
1005 */
1006 vlan->tap_features = feature_mask;
1007 vlan->set_features = features;
1008 netdev_update_features(vlan->dev);
1009
1010 return 0;
1011 }
1012
1013 /*
1014 * provide compatibility with generic tun/tap interface
1015 */
1016 static long macvtap_ioctl(struct file *file, unsigned int cmd,
1017 unsigned long arg)
1018 {
1019 struct macvtap_queue *q = file->private_data;
1020 struct macvlan_dev *vlan;
1021 void __user *argp = (void __user *)arg;
1022 struct ifreq __user *ifr = argp;
1023 unsigned int __user *up = argp;
1024 unsigned short u;
1025 int __user *sp = argp;
1026 struct sockaddr sa;
1027 int s;
1028 int ret;
1029
1030 switch (cmd) {
1031 case TUNSETIFF:
1032 /* ignore the name, just look at flags */
1033 if (get_user(u, &ifr->ifr_flags))
1034 return -EFAULT;
1035
1036 ret = 0;
1037 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP))
1038 ret = -EINVAL;
1039 else
1040 q->flags = (q->flags & ~MACVTAP_FEATURES) | u;
1041
1042 return ret;
1043
1044 case TUNGETIFF:
1045 rtnl_lock();
1046 vlan = macvtap_get_vlan(q);
1047 if (!vlan) {
1048 rtnl_unlock();
1049 return -ENOLINK;
1050 }
1051
1052 ret = 0;
1053 u = q->flags;
1054 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1055 put_user(u, &ifr->ifr_flags))
1056 ret = -EFAULT;
1057 macvtap_put_vlan(vlan);
1058 rtnl_unlock();
1059 return ret;
1060
1061 case TUNSETQUEUE:
1062 if (get_user(u, &ifr->ifr_flags))
1063 return -EFAULT;
1064 rtnl_lock();
1065 ret = macvtap_ioctl_set_queue(file, u);
1066 rtnl_unlock();
1067 return ret;
1068
1069 case TUNGETFEATURES:
1070 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up))
1071 return -EFAULT;
1072 return 0;
1073
1074 case TUNSETSNDBUF:
1075 if (get_user(s, sp))
1076 return -EFAULT;
1077
1078 q->sk.sk_sndbuf = s;
1079 return 0;
1080
1081 case TUNGETVNETHDRSZ:
1082 s = q->vnet_hdr_sz;
1083 if (put_user(s, sp))
1084 return -EFAULT;
1085 return 0;
1086
1087 case TUNSETVNETHDRSZ:
1088 if (get_user(s, sp))
1089 return -EFAULT;
1090 if (s < (int)sizeof(struct virtio_net_hdr))
1091 return -EINVAL;
1092
1093 q->vnet_hdr_sz = s;
1094 return 0;
1095
1096 case TUNGETVNETLE:
1097 s = !!(q->flags & MACVTAP_VNET_LE);
1098 if (put_user(s, sp))
1099 return -EFAULT;
1100 return 0;
1101
1102 case TUNSETVNETLE:
1103 if (get_user(s, sp))
1104 return -EFAULT;
1105 if (s)
1106 q->flags |= MACVTAP_VNET_LE;
1107 else
1108 q->flags &= ~MACVTAP_VNET_LE;
1109 return 0;
1110
1111 case TUNGETVNETBE:
1112 return macvtap_get_vnet_be(q, sp);
1113
1114 case TUNSETVNETBE:
1115 return macvtap_set_vnet_be(q, sp);
1116
1117 case TUNSETOFFLOAD:
1118 /* let the user check for future flags */
1119 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
1120 TUN_F_TSO_ECN | TUN_F_UFO))
1121 return -EINVAL;
1122
1123 rtnl_lock();
1124 ret = set_offload(q, arg);
1125 rtnl_unlock();
1126 return ret;
1127
1128 case SIOCGIFHWADDR:
1129 rtnl_lock();
1130 vlan = macvtap_get_vlan(q);
1131 if (!vlan) {
1132 rtnl_unlock();
1133 return -ENOLINK;
1134 }
1135 ret = 0;
1136 u = vlan->dev->type;
1137 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
1138 copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) ||
1139 put_user(u, &ifr->ifr_hwaddr.sa_family))
1140 ret = -EFAULT;
1141 macvtap_put_vlan(vlan);
1142 rtnl_unlock();
1143 return ret;
1144
1145 case SIOCSIFHWADDR:
1146 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa)))
1147 return -EFAULT;
1148 rtnl_lock();
1149 vlan = macvtap_get_vlan(q);
1150 if (!vlan) {
1151 rtnl_unlock();
1152 return -ENOLINK;
1153 }
1154 ret = dev_set_mac_address(vlan->dev, &sa);
1155 macvtap_put_vlan(vlan);
1156 rtnl_unlock();
1157 return ret;
1158
1159 default:
1160 return -EINVAL;
1161 }
1162 }
1163
1164 #ifdef CONFIG_COMPAT
1165 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
1166 unsigned long arg)
1167 {
1168 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
1169 }
1170 #endif
1171
1172 static const struct file_operations macvtap_fops = {
1173 .owner = THIS_MODULE,
1174 .open = macvtap_open,
1175 .release = macvtap_release,
1176 .read_iter = macvtap_read_iter,
1177 .write_iter = macvtap_write_iter,
1178 .poll = macvtap_poll,
1179 .llseek = no_llseek,
1180 .unlocked_ioctl = macvtap_ioctl,
1181 #ifdef CONFIG_COMPAT
1182 .compat_ioctl = macvtap_compat_ioctl,
1183 #endif
1184 };
1185
1186 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m,
1187 size_t total_len)
1188 {
1189 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1190 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
1191 }
1192
1193 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m,
1194 size_t total_len, int flags)
1195 {
1196 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
1197 int ret;
1198 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
1199 return -EINVAL;
1200 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
1201 if (ret > total_len) {
1202 m->msg_flags |= MSG_TRUNC;
1203 ret = flags & MSG_TRUNC ? ret : total_len;
1204 }
1205 return ret;
1206 }
1207
1208 static int macvtap_peek_len(struct socket *sock)
1209 {
1210 struct macvtap_queue *q = container_of(sock, struct macvtap_queue,
1211 sock);
1212 return skb_array_peek_len(&q->skb_array);
1213 }
1214
1215 /* Ops structure to mimic raw sockets with tun */
1216 static const struct proto_ops macvtap_socket_ops = {
1217 .sendmsg = macvtap_sendmsg,
1218 .recvmsg = macvtap_recvmsg,
1219 .peek_len = macvtap_peek_len,
1220 };
1221
1222 /* Get an underlying socket object from tun file. Returns error unless file is
1223 * attached to a device. The returned object works like a packet socket, it
1224 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for
1225 * holding a reference to the file for as long as the socket is in use. */
1226 struct socket *macvtap_get_socket(struct file *file)
1227 {
1228 struct macvtap_queue *q;
1229 if (file->f_op != &macvtap_fops)
1230 return ERR_PTR(-EINVAL);
1231 q = file->private_data;
1232 if (!q)
1233 return ERR_PTR(-EBADFD);
1234 return &q->sock;
1235 }
1236 EXPORT_SYMBOL_GPL(macvtap_get_socket);
1237
1238 static int macvtap_queue_resize(struct macvlan_dev *vlan)
1239 {
1240 struct net_device *dev = vlan->dev;
1241 struct macvtap_queue *q;
1242 struct skb_array **arrays;
1243 int n = vlan->numqueues;
1244 int ret, i = 0;
1245
1246 arrays = kmalloc(sizeof *arrays * n, GFP_KERNEL);
1247 if (!arrays)
1248 return -ENOMEM;
1249
1250 list_for_each_entry(q, &vlan->queue_list, next)
1251 arrays[i++] = &q->skb_array;
1252
1253 ret = skb_array_resize_multiple(arrays, n,
1254 dev->tx_queue_len, GFP_KERNEL);
1255
1256 kfree(arrays);
1257 return ret;
1258 }
1259
1260 static int macvtap_device_event(struct notifier_block *unused,
1261 unsigned long event, void *ptr)
1262 {
1263 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
1264 struct macvlan_dev *vlan;
1265 struct device *classdev;
1266 dev_t devt;
1267 int err;
1268 char tap_name[IFNAMSIZ];
1269
1270 if (dev->rtnl_link_ops != &macvtap_link_ops)
1271 return NOTIFY_DONE;
1272
1273 snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
1274 vlan = netdev_priv(dev);
1275
1276 switch (event) {
1277 case NETDEV_REGISTER:
1278 /* Create the device node here after the network device has
1279 * been registered but before register_netdevice has
1280 * finished running.
1281 */
1282 err = macvtap_get_minor(vlan);
1283 if (err)
1284 return notifier_from_errno(err);
1285
1286 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1287 classdev = device_create(&macvtap_class, &dev->dev, devt,
1288 dev, tap_name);
1289 if (IS_ERR(classdev)) {
1290 macvtap_free_minor(vlan);
1291 return notifier_from_errno(PTR_ERR(classdev));
1292 }
1293 err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
1294 tap_name);
1295 if (err)
1296 return notifier_from_errno(err);
1297 break;
1298 case NETDEV_UNREGISTER:
1299 /* vlan->minor == 0 if NETDEV_REGISTER above failed */
1300 if (vlan->minor == 0)
1301 break;
1302 sysfs_remove_link(&dev->dev.kobj, tap_name);
1303 devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1304 device_destroy(&macvtap_class, devt);
1305 macvtap_free_minor(vlan);
1306 break;
1307 case NETDEV_CHANGE_TX_QUEUE_LEN:
1308 if (macvtap_queue_resize(vlan))
1309 return NOTIFY_BAD;
1310 break;
1311 }
1312
1313 return NOTIFY_DONE;
1314 }
1315
1316 static struct notifier_block macvtap_notifier_block __read_mostly = {
1317 .notifier_call = macvtap_device_event,
1318 };
1319
1320 static int macvtap_init(void)
1321 {
1322 int err;
1323
1324 err = alloc_chrdev_region(&macvtap_major, 0,
1325 MACVTAP_NUM_DEVS, "macvtap");
1326 if (err)
1327 goto out1;
1328
1329 cdev_init(&macvtap_cdev, &macvtap_fops);
1330 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
1331 if (err)
1332 goto out2;
1333
1334 err = class_register(&macvtap_class);
1335 if (err)
1336 goto out3;
1337
1338 err = register_netdevice_notifier(&macvtap_notifier_block);
1339 if (err)
1340 goto out4;
1341
1342 err = macvlan_link_register(&macvtap_link_ops);
1343 if (err)
1344 goto out5;
1345
1346 return 0;
1347
1348 out5:
1349 unregister_netdevice_notifier(&macvtap_notifier_block);
1350 out4:
1351 class_unregister(&macvtap_class);
1352 out3:
1353 cdev_del(&macvtap_cdev);
1354 out2:
1355 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1356 out1:
1357 return err;
1358 }
1359 module_init(macvtap_init);
1360
1361 static void macvtap_exit(void)
1362 {
1363 rtnl_link_unregister(&macvtap_link_ops);
1364 unregister_netdevice_notifier(&macvtap_notifier_block);
1365 class_unregister(&macvtap_class);
1366 cdev_del(&macvtap_cdev);
1367 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
1368 idr_destroy(&minor_idr);
1369 }
1370 module_exit(macvtap_exit);
1371
1372 MODULE_ALIAS_RTNL_LINK("macvtap");
1373 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
1374 MODULE_LICENSE("GPL");
Linux with added FPC-III support