macvtap.c 27.5 KB
Newer Older
A
Arnd Bergmann 已提交
1 2
#include <linux/etherdevice.h>
#include <linux/if_macvlan.h>
3
#include <linux/if_vlan.h>
A
Arnd Bergmann 已提交
4 5 6 7 8 9 10 11 12
#include <linux/interrupt.h>
#include <linux/nsproxy.h>
#include <linux/compat.h>
#include <linux/if_tun.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/cache.h>
#include <linux/sched.h>
#include <linux/types.h>
13
#include <linux/slab.h>
A
Arnd Bergmann 已提交
14 15 16
#include <linux/init.h>
#include <linux/wait.h>
#include <linux/cdev.h>
A
Al Viro 已提交
17
#include <linux/idr.h>
A
Arnd Bergmann 已提交
18 19 20 21 22
#include <linux/fs.h>

#include <net/net_namespace.h>
#include <net/rtnetlink.h>
#include <net/sock.h>
23
#include <linux/virtio_net.h>
A
Arnd Bergmann 已提交
24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41

/*
 * A macvtap queue is the central object of this driver, it connects
 * an open character device to a macvlan interface. There can be
 * multiple queues on one interface, which map back to queues
 * implemented in hardware on the underlying device.
 *
 * macvtap_proto is used to allocate queues through the sock allocation
 * mechanism.
 *
 * TODO: multiqueue support is currently not implemented, even though
 * macvtap is basically prepared for that. We will need to add this
 * here as well as in virtio-net and qemu to get line rate on 10gbit
 * adapters from a guest.
 */
struct macvtap_queue {
	struct sock sk;
	struct socket sock;
42
	struct socket_wq wq;
43
	int vnet_hdr_sz;
44
	struct macvlan_dev __rcu *vlan;
A
Arnd Bergmann 已提交
45
	struct file *file;
46
	unsigned int flags;
A
Arnd Bergmann 已提交
47 48 49 50 51 52 53 54 55
};

static struct proto macvtap_proto = {
	.name = "macvtap",
	.owner = THIS_MODULE,
	.obj_size = sizeof (struct macvtap_queue),
};

/*
56
 * Variables for dealing with macvtaps device numbers.
A
Arnd Bergmann 已提交
57
 */
58
static dev_t macvtap_major;
59 60 61 62
#define MACVTAP_NUM_DEVS (1U << MINORBITS)
static DEFINE_MUTEX(minor_lock);
static DEFINE_IDR(minor_idr);

63
#define GOODCOPY_LEN 128
A
Arnd Bergmann 已提交
64 65 66
static struct class *macvtap_class;
static struct cdev macvtap_cdev;

67 68
static const struct proto_ops macvtap_socket_ops;

A
Arnd Bergmann 已提交
69 70
/*
 * RCU usage:
71 72 73
 * The macvtap_queue and the macvlan_dev are loosely coupled, the
 * pointers from one to the other can only be read while rcu_read_lock
 * or macvtap_lock is held.
A
Arnd Bergmann 已提交
74
 *
75 76 77 78
 * Both the file and the macvlan_dev hold a reference on the macvtap_queue
 * through sock_hold(&q->sk). When the macvlan_dev goes away first,
 * q->vlan becomes inaccessible. When the files gets closed,
 * macvtap_get_queue() fails.
A
Arnd Bergmann 已提交
79
 *
80 81 82 83
 * There may still be references to the struct sock inside of the
 * queue from outbound SKBs, but these never reference back to the
 * file or the dev. The data structure is freed through __sk_free
 * when both our references and any pending SKBs are gone.
A
Arnd Bergmann 已提交
84 85 86 87
 */
static DEFINE_SPINLOCK(macvtap_lock);

/*
88 89 90
 * get_slot: return a [unused/occupied] slot in vlan->taps[]:
 *	- if 'q' is NULL, return the first empty slot;
 *	- otherwise, return the slot this pointer occupies.
A
Arnd Bergmann 已提交
91
 */
92 93 94 95 96
static int get_slot(struct macvlan_dev *vlan, struct macvtap_queue *q)
{
	int i;

	for (i = 0; i < MAX_MACVTAP_QUEUES; i++) {
97 98
		if (rcu_dereference_protected(vlan->taps[i],
					      lockdep_is_held(&macvtap_lock)) == q)
99 100 101 102 103 104 105
			return i;
	}

	/* Should never happen */
	BUG_ON(1);
}

A
Arnd Bergmann 已提交
106 107 108 109
static int macvtap_set_queue(struct net_device *dev, struct file *file,
				struct macvtap_queue *q)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
110
	int index;
A
Arnd Bergmann 已提交
111 112 113
	int err = -EBUSY;

	spin_lock(&macvtap_lock);
114
	if (vlan->numvtaps == MAX_MACVTAP_QUEUES)
A
Arnd Bergmann 已提交
115 116 117
		goto out;

	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);
A
Arnd Bergmann 已提交
122 123

	q->file = file;
124
	file->private_data = q;
A
Arnd Bergmann 已提交
125

126 127
	vlan->numvtaps++;

A
Arnd Bergmann 已提交
128 129 130 131 132 133
out:
	spin_unlock(&macvtap_lock);
	return err;
}

/*
134 135 136
 * The file owning the queue got closed, give up both
 * the reference that the files holds as well as the
 * one from the macvlan_dev if that still exists.
A
Arnd Bergmann 已提交
137 138 139 140
 *
 * Using the spinlock makes sure that we don't get
 * to the queue again after destroying it.
 */
141
static void macvtap_put_queue(struct macvtap_queue *q)
A
Arnd Bergmann 已提交
142
{
143
	struct macvlan_dev *vlan;
A
Arnd Bergmann 已提交
144 145

	spin_lock(&macvtap_lock);
146 147
	vlan = rcu_dereference_protected(q->vlan,
					 lockdep_is_held(&macvtap_lock));
148
	if (vlan) {
149 150
		int index = get_slot(vlan, q);

151 152
		RCU_INIT_POINTER(vlan->taps[index], NULL);
		RCU_INIT_POINTER(q->vlan, NULL);
153
		sock_put(&q->sk);
154
		--vlan->numvtaps;
A
Arnd Bergmann 已提交
155 156 157 158 159 160 161 162 163
	}

	spin_unlock(&macvtap_lock);

	synchronize_rcu();
	sock_put(&q->sk);
}

/*
164 165 166 167 168
 * Select a queue based on the rxq of the device on which this packet
 * arrived. If the incoming device is not mq, calculate a flow hash
 * to select a queue. If all fails, find the first available queue.
 * Cache vlan->numvtaps since it can become zero during the execution
 * of this function.
A
Arnd Bergmann 已提交
169 170 171 172 173
 */
static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
					       struct sk_buff *skb)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
174 175 176 177 178 179 180
	struct macvtap_queue *tap = NULL;
	int numvtaps = vlan->numvtaps;
	__u32 rxq;

	if (!numvtaps)
		goto out;

181 182 183 184 185 186 187 188
	/* Check if we can use flow to select a queue */
	rxq = skb_get_rxhash(skb);
	if (rxq) {
		tap = rcu_dereference(vlan->taps[rxq % numvtaps]);
		if (tap)
			goto out;
	}

189 190
	if (likely(skb_rx_queue_recorded(skb))) {
		rxq = skb_get_rx_queue(skb);
A
Arnd Bergmann 已提交
191

192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208
		while (unlikely(rxq >= numvtaps))
			rxq -= numvtaps;

		tap = rcu_dereference(vlan->taps[rxq]);
		if (tap)
			goto out;
	}

	/* Everything failed - find first available queue */
	for (rxq = 0; rxq < MAX_MACVTAP_QUEUES; rxq++) {
		tap = rcu_dereference(vlan->taps[rxq]);
		if (tap)
			break;
	}

out:
	return tap;
A
Arnd Bergmann 已提交
209 210
}

211 212
/*
 * The net_device is going away, give up the reference
213 214
 * that it holds on all queues and safely set the pointer
 * from the queues to NULL.
215
 */
A
Arnd Bergmann 已提交
216 217 218
static void macvtap_del_queues(struct net_device *dev)
{
	struct macvlan_dev *vlan = netdev_priv(dev);
219 220
	struct macvtap_queue *q, *qlist[MAX_MACVTAP_QUEUES];
	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++) {
225 226
		q = rcu_dereference_protected(vlan->taps[i],
					      lockdep_is_held(&macvtap_lock));
227 228
		if (q) {
			qlist[j++] = q;
229 230
			RCU_INIT_POINTER(vlan->taps[i], NULL);
			RCU_INIT_POINTER(q->vlan, NULL);
231 232
			vlan->numvtaps--;
		}
233
	}
234
	BUG_ON(vlan->numvtaps != 0);
235 236
	/* guarantee that any future macvtap_set_queue will fail */
	vlan->numvtaps = MAX_MACVTAP_QUEUES;
237 238 239
	spin_unlock(&macvtap_lock);

	synchronize_rcu();
240 241 242

	for (--j; j >= 0; j--)
		sock_put(&qlist[j]->sk);
A
Arnd Bergmann 已提交
243 244 245 246 247 248 249 250 251 252 253
}

/*
 * Forward happens for data that gets sent from one macvlan
 * endpoint to another one in bridge mode. We just take
 * the skb and put it into the receive queue.
 */
static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
{
	struct macvtap_queue *q = macvtap_get_queue(dev, skb);
	if (!q)
254 255 256 257
		goto drop;

	if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len)
		goto drop;
A
Arnd Bergmann 已提交
258 259

	skb_queue_tail(&q->sk.sk_receive_queue, skb);
E
Eric Dumazet 已提交
260
	wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND);
261 262 263 264 265
	return NET_RX_SUCCESS;

drop:
	kfree_skb(skb);
	return NET_RX_DROP;
A
Arnd Bergmann 已提交
266 267 268 269 270 271 272 273 274 275 276 277 278
}

/*
 * Receive is for data from the external interface (lowerdev),
 * in case of macvtap, we can treat that the same way as
 * forward, which macvlan cannot.
 */
static int macvtap_receive(struct sk_buff *skb)
{
	skb_push(skb, ETH_HLEN);
	return macvtap_forward(skb->dev, skb);
}

279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330
static int macvtap_get_minor(struct macvlan_dev *vlan)
{
	int retval = -ENOMEM;
	int id;

	mutex_lock(&minor_lock);
	if (idr_pre_get(&minor_idr, GFP_KERNEL) == 0)
		goto exit;

	retval = idr_get_new_above(&minor_idr, vlan, 1, &id);
	if (retval < 0) {
		if (retval == -EAGAIN)
			retval = -ENOMEM;
		goto exit;
	}
	if (id < MACVTAP_NUM_DEVS) {
		vlan->minor = id;
	} else {
		printk(KERN_ERR "too many macvtap devices\n");
		retval = -EINVAL;
		idr_remove(&minor_idr, id);
	}
exit:
	mutex_unlock(&minor_lock);
	return retval;
}

static void macvtap_free_minor(struct macvlan_dev *vlan)
{
	mutex_lock(&minor_lock);
	if (vlan->minor) {
		idr_remove(&minor_idr, vlan->minor);
		vlan->minor = 0;
	}
	mutex_unlock(&minor_lock);
}

static struct net_device *dev_get_by_macvtap_minor(int minor)
{
	struct net_device *dev = NULL;
	struct macvlan_dev *vlan;

	mutex_lock(&minor_lock);
	vlan = idr_find(&minor_idr, minor);
	if (vlan) {
		dev = vlan->dev;
		dev_hold(dev);
	}
	mutex_unlock(&minor_lock);
	return dev;
}

A
Arnd Bergmann 已提交
331 332 333 334 335
static int macvtap_newlink(struct net *src_net,
			   struct net_device *dev,
			   struct nlattr *tb[],
			   struct nlattr *data[])
{
336 337 338 339 340
	/* Don't put anything that may fail after macvlan_common_newlink
	 * because we can't undo what it does.
	 */
	return macvlan_common_newlink(src_net, dev, tb, data,
				      macvtap_receive, macvtap_forward);
A
Arnd Bergmann 已提交
341 342 343 344 345 346 347 348 349
}

static void macvtap_dellink(struct net_device *dev,
			    struct list_head *head)
{
	macvtap_del_queues(dev);
	macvlan_dellink(dev, head);
}

350 351 352 353 354 355
static void macvtap_setup(struct net_device *dev)
{
	macvlan_common_setup(dev);
	dev->tx_queue_len = TUN_READQ_SIZE;
}

A
Arnd Bergmann 已提交
356 357
static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
	.kind		= "macvtap",
358
	.setup		= macvtap_setup,
A
Arnd Bergmann 已提交
359 360 361 362 363 364 365
	.newlink	= macvtap_newlink,
	.dellink	= macvtap_dellink,
};


static void macvtap_sock_write_space(struct sock *sk)
{
366 367
	wait_queue_head_t *wqueue;

A
Arnd Bergmann 已提交
368 369 370 371
	if (!sock_writeable(sk) ||
	    !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
		return;

372 373 374
	wqueue = sk_sleep(sk);
	if (wqueue && waitqueue_active(wqueue))
		wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND);
A
Arnd Bergmann 已提交
375 376
}

377 378 379 380 381
static void macvtap_sock_destruct(struct sock *sk)
{
	skb_queue_purge(&sk->sk_receive_queue);
}

A
Arnd Bergmann 已提交
382 383 384
static int macvtap_open(struct inode *inode, struct file *file)
{
	struct net *net = current->nsproxy->net_ns;
385
	struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode));
A
Arnd Bergmann 已提交
386 387 388 389 390 391 392 393 394 395 396 397 398
	struct macvtap_queue *q;
	int err;

	err = -ENODEV;
	if (!dev)
		goto out;

	err = -ENOMEM;
	q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
					     &macvtap_proto);
	if (!q)
		goto out;

399 400
	q->sock.wq = &q->wq;
	init_waitqueue_head(&q->wq.wait);
A
Arnd Bergmann 已提交
401 402
	q->sock.type = SOCK_RAW;
	q->sock.state = SS_CONNECTED;
403 404
	q->sock.file = file;
	q->sock.ops = &macvtap_socket_ops;
A
Arnd Bergmann 已提交
405 406
	sock_init_data(&q->sock, &q->sk);
	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);
A
Arnd Bergmann 已提交
410

411 412 413
	/*
	 * so far only KVM virtio_net uses macvtap, enable zero copy between
	 * guest kernel and host kernel when lower device supports zerocopy
414 415 416
	 *
	 * The macvlan supports zerocopy iff the lower device supports zero
	 * copy so we don't have to look at the lower device directly.
417
	 */
418 419
	if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG))
		sock_set_flag(&q->sk, SOCK_ZEROCOPY);
420

A
Arnd Bergmann 已提交
421 422 423 424 425 426 427 428 429 430 431 432 433
	err = macvtap_set_queue(dev, file, q);
	if (err)
		sock_put(&q->sk);

out:
	if (dev)
		dev_put(dev);

	return err;
}

static int macvtap_release(struct inode *inode, struct file *file)
{
434 435
	struct macvtap_queue *q = file->private_data;
	macvtap_put_queue(q);
A
Arnd Bergmann 已提交
436 437 438 439 440
	return 0;
}

static unsigned int macvtap_poll(struct file *file, poll_table * wait)
{
441
	struct macvtap_queue *q = file->private_data;
A
Arnd Bergmann 已提交
442 443 444 445 446 447
	unsigned int mask = POLLERR;

	if (!q)
		goto out;

	mask = 0;
448
	poll_wait(file, &q->wq.wait, wait);
A
Arnd Bergmann 已提交
449 450 451 452 453 454 455 456 457 458 459 460 461

	if (!skb_queue_empty(&q->sk.sk_receive_queue))
		mask |= POLLIN | POLLRDNORM;

	if (sock_writeable(&q->sk) ||
	    (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
	     sock_writeable(&q->sk)))
		mask |= POLLOUT | POLLWRNORM;

out:
	return mask;
}

462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484
static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
						size_t len, size_t linear,
						int noblock, int *err)
{
	struct sk_buff *skb;

	/* Under a page?  Don't bother with paged skb. */
	if (prepad + len < PAGE_SIZE || !linear)
		linear = len;

	skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
				   err);
	if (!skb)
		return NULL;

	skb_reserve(skb, prepad);
	skb_put(skb, linear);
	skb->data_len = len - linear;
	skb->len += len - linear;

	return skb;
}

485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509
/* set skb frags from iovec, this can move to core network code for reuse */
static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from,
				  int offset, size_t count)
{
	int len = iov_length(from, count) - offset;
	int copy = skb_headlen(skb);
	int size, offset1 = 0;
	int i = 0;

	/* Skip over from offset */
	while (count && (offset >= from->iov_len)) {
		offset -= from->iov_len;
		++from;
		--count;
	}

	/* copy up to skb headlen */
	while (count && (copy > 0)) {
		size = min_t(unsigned int, copy, from->iov_len - offset);
		if (copy_from_user(skb->data + offset1, from->iov_base + offset,
				   size))
			return -EFAULT;
		if (copy > size) {
			++from;
			--count;
510 511 512
			offset = 0;
		} else
			offset += size;
513 514 515 516 517 518 519 520 521 522 523
		copy -= size;
		offset1 += size;
	}

	if (len == offset1)
		return 0;

	while (count--) {
		struct page *page[MAX_SKB_FRAGS];
		int num_pages;
		unsigned long base;
524
		unsigned long truesize;
525

526
		len = from->iov_len - offset;
527
		if (!len) {
528
			offset = 0;
529 530 531
			++from;
			continue;
		}
532
		base = (unsigned long)from->iov_base + offset;
533
		size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT;
534 535
		if (i + size > MAX_SKB_FRAGS)
			return -EMSGSIZE;
536
		num_pages = get_user_pages_fast(base, size, 0, &page[i]);
537
		if (num_pages != size) {
538 539
			for (i = 0; i < num_pages; i++)
				put_page(page[i]);
540
			return -EFAULT;
541
		}
542
		truesize = size * PAGE_SIZE;
543 544
		skb->data_len += len;
		skb->len += len;
545 546
		skb->truesize += truesize;
		atomic_add(truesize, &skb->sk->sk_wmem_alloc);
547
		while (len) {
548 549 550
			int off = base & ~PAGE_MASK;
			int size = min_t(int, len, PAGE_SIZE - off);
			__skb_fill_page_desc(skb, i, page[i], off, size);
551 552
			skb_shinfo(skb)->nr_frags++;
			/* increase sk_wmem_alloc */
553 554
			base += size;
			len -= size;
555 556
			i++;
		}
557
		offset = 0;
558 559 560 561 562
		++from;
	}
	return 0;
}

563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635
/*
 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
 * be shared with the tun/tap driver.
 */
static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
				     struct virtio_net_hdr *vnet_hdr)
{
	unsigned short gso_type = 0;
	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
		case VIRTIO_NET_HDR_GSO_TCPV4:
			gso_type = SKB_GSO_TCPV4;
			break;
		case VIRTIO_NET_HDR_GSO_TCPV6:
			gso_type = SKB_GSO_TCPV6;
			break;
		case VIRTIO_NET_HDR_GSO_UDP:
			gso_type = SKB_GSO_UDP;
			break;
		default:
			return -EINVAL;
		}

		if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
			gso_type |= SKB_GSO_TCP_ECN;

		if (vnet_hdr->gso_size == 0)
			return -EINVAL;
	}

	if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
		if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
					  vnet_hdr->csum_offset))
			return -EINVAL;
	}

	if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
		skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
		skb_shinfo(skb)->gso_type = gso_type;

		/* Header must be checked, and gso_segs computed. */
		skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
		skb_shinfo(skb)->gso_segs = 0;
	}
	return 0;
}

static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
				   struct virtio_net_hdr *vnet_hdr)
{
	memset(vnet_hdr, 0, sizeof(*vnet_hdr));

	if (skb_is_gso(skb)) {
		struct skb_shared_info *sinfo = skb_shinfo(skb);

		/* This is a hint as to how much should be linear. */
		vnet_hdr->hdr_len = skb_headlen(skb);
		vnet_hdr->gso_size = sinfo->gso_size;
		if (sinfo->gso_type & SKB_GSO_TCPV4)
			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
		else if (sinfo->gso_type & SKB_GSO_TCPV6)
			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
		else if (sinfo->gso_type & SKB_GSO_UDP)
			vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
		else
			BUG();
		if (sinfo->gso_type & SKB_GSO_TCP_ECN)
			vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
	} else
		vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;

	if (skb->ip_summed == CHECKSUM_PARTIAL) {
		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;
638 639
	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
		vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
640 641 642 643 644 645
	} /* else everything is zero */

	return 0;
}


A
Arnd Bergmann 已提交
646
/* Get packet from user space buffer */
647 648 649
static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
				const struct iovec *iv, unsigned long total_len,
				size_t count, int noblock)
A
Arnd Bergmann 已提交
650 651
{
	struct sk_buff *skb;
652
	struct macvlan_dev *vlan;
653
	unsigned long len = total_len;
A
Arnd Bergmann 已提交
654
	int err;
655 656
	struct virtio_net_hdr vnet_hdr = { 0 };
	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));
670 671 672 673 674 675 676 677 678 679 680
		if (err < 0)
			goto err;
		if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
		     vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
							vnet_hdr.hdr_len)
			vnet_hdr.hdr_len = vnet_hdr.csum_start +
						vnet_hdr.csum_offset + 2;
		err = -EINVAL;
		if (vnet_hdr.hdr_len > len)
			goto err;
	}
A
Arnd Bergmann 已提交
681

682
	err = -EINVAL;
A
Arnd Bergmann 已提交
683
	if (unlikely(len < ETH_HLEN))
684
		goto err;
A
Arnd Bergmann 已提交
685

686 687 688 689
	err = -EMSGSIZE;
	if (unlikely(count > UIO_MAXIOV))
		goto err;

690 691 692 693
	if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY))
		zerocopy = true;

	if (zerocopy) {
694 695 696 697 698 699 700 701 702 703 704
		/* Userspace may produce vectors with count greater than
		 * MAX_SKB_FRAGS, so we need to linearize parts of the skb
		 * to let the rest of data to be fit in the frags.
		 */
		if (count > MAX_SKB_FRAGS) {
			copylen = iov_length(iv, count - MAX_SKB_FRAGS);
			if (copylen < vnet_hdr_len)
				copylen = 0;
			else
				copylen -= vnet_hdr_len;
		}
705 706 707 708
		/* There are 256 bytes to be copied in skb, so there is enough
		 * room for skb expand head in case it is used.
		 * The rest buffer is mapped from userspace.
		 */
709 710
		if (copylen < vnet_hdr.hdr_len)
			copylen = vnet_hdr.hdr_len;
711 712 713 714 715 716 717
		if (!copylen)
			copylen = GOODCOPY_LEN;
	} else
		copylen = len;

	skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen,
				vnet_hdr.hdr_len, noblock, &err);
718 719
	if (!skb)
		goto err;
A
Arnd Bergmann 已提交
720

721
	if (zerocopy)
722
		err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count);
723
	else
724 725
		err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len,
						   len);
726
	if (err)
727
		goto err_kfree;
A
Arnd Bergmann 已提交
728 729

	skb_set_network_header(skb, ETH_HLEN);
730 731 732 733 734 735 736 737 738
	skb_reset_mac_header(skb);
	skb->protocol = eth_hdr(skb)->h_proto;

	if (vnet_hdr_len) {
		err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
		if (err)
			goto err_kfree;
	}

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;
744 745
		skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY;
	}
746 747 748 749 750
	if (vlan)
		macvlan_start_xmit(skb, vlan->dev);
	else
		kfree_skb(skb);
	rcu_read_unlock_bh();
A
Arnd Bergmann 已提交
751

752
	return total_len;
753

754 755 756
err_kfree:
	kfree_skb(skb);

757 758
err:
	rcu_read_lock_bh();
759
	vlan = rcu_dereference_bh(q->vlan);
760
	if (vlan)
761
		vlan->dev->stats.tx_dropped++;
762 763 764
	rcu_read_unlock_bh();

	return err;
A
Arnd Bergmann 已提交
765 766 767 768 769 770 771
}

static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
				 unsigned long count, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	ssize_t result = -ENOLINK;
772
	struct macvtap_queue *q = file->private_data;
A
Arnd Bergmann 已提交
773

774 775
	result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count,
				  file->f_flags & O_NONBLOCK);
A
Arnd Bergmann 已提交
776 777 778 779 780 781 782 783
	return result;
}

/* Put packet to the user space buffer */
static ssize_t macvtap_put_user(struct macvtap_queue *q,
				const struct sk_buff *skb,
				const struct iovec *iv, int len)
{
784
	struct macvlan_dev *vlan;
A
Arnd Bergmann 已提交
785
	int ret;
786
	int vnet_hdr_len = 0;
787 788
	int vlan_offset = 0;
	int copied;
789 790 791

	if (q->flags & IFF_VNET_HDR) {
		struct virtio_net_hdr vnet_hdr;
792
		vnet_hdr_len = q->vnet_hdr_sz;
793 794 795 796 797 798 799
		if ((len -= vnet_hdr_len) < 0)
			return -EINVAL;

		ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
		if (ret)
			return ret;

800
		if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr)))
801 802
			return -EFAULT;
	}
803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832
	copied = vnet_hdr_len;

	if (!vlan_tx_tag_present(skb))
		len = min_t(int, skb->len, len);
	else {
		int copy;
		struct {
			__be16 h_vlan_proto;
			__be16 h_vlan_TCI;
		} veth;
		veth.h_vlan_proto = htons(ETH_P_8021Q);
		veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb));

		vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto);
		len = min_t(int, skb->len + VLAN_HLEN, len);

		copy = min_t(int, vlan_offset, len);
		ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy);
		len -= copy;
		copied += copy;
		if (ret || !len)
			goto done;

		copy = min_t(int, sizeof(veth), len);
		ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy);
		len -= copy;
		copied += copy;
		if (ret || !len)
			goto done;
	}
A
Arnd Bergmann 已提交
833

834 835
	ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len);
	copied += len;
A
Arnd Bergmann 已提交
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();
A
Arnd Bergmann 已提交
843

844
	return ret ? ret : copied;
A
Arnd Bergmann 已提交
845 846
}

847 848 849
static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
			       const struct iovec *iv, unsigned long len,
			       int noblock)
A
Arnd Bergmann 已提交
850
{
851
	DEFINE_WAIT(wait);
A
Arnd Bergmann 已提交
852
	struct sk_buff *skb;
853
	ssize_t ret = 0;
A
Arnd Bergmann 已提交
854 855

	while (len) {
856
		prepare_to_wait(sk_sleep(&q->sk), &wait, TASK_INTERRUPTIBLE);
A
Arnd Bergmann 已提交
857 858 859 860

		/* Read frames from the queue */
		skb = skb_dequeue(&q->sk.sk_receive_queue);
		if (!skb) {
861
			if (noblock) {
A
Arnd Bergmann 已提交
862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877
				ret = -EAGAIN;
				break;
			}
			if (signal_pending(current)) {
				ret = -ERESTARTSYS;
				break;
			}
			/* Nothing to read, let's sleep */
			schedule();
			continue;
		}
		ret = macvtap_put_user(q, skb, iv, len);
		kfree_skb(skb);
		break;
	}

878
	finish_wait(sk_sleep(&q->sk), &wait);
879 880 881 882 883 884 885 886 887
	return ret;
}

static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
				unsigned long count, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct macvtap_queue *q = file->private_data;
	ssize_t len, ret = 0;
A
Arnd Bergmann 已提交
888

889 890 891 892 893 894 895 896
	len = iov_length(iv, count);
	if (len < 0) {
		ret = -EINVAL;
		goto out;
	}

	ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
	ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
A
Arnd Bergmann 已提交
897 898 899 900 901 902 903 904 905 906
out:
	return ret;
}

/*
 * provide compatibility with generic tun/tap interface
 */
static long macvtap_ioctl(struct file *file, unsigned int cmd,
			  unsigned long arg)
{
907 908
	struct macvtap_queue *q = file->private_data;
	struct macvlan_dev *vlan;
A
Arnd Bergmann 已提交
909 910 911 912
	void __user *argp = (void __user *)arg;
	struct ifreq __user *ifr = argp;
	unsigned int __user *up = argp;
	unsigned int u;
913 914
	int __user *sp = argp;
	int s;
915
	int ret;
A
Arnd Bergmann 已提交
916 917 918 919 920 921

	switch (cmd) {
	case TUNSETIFF:
		/* ignore the name, just look at flags */
		if (get_user(u, &ifr->ifr_flags))
			return -EFAULT;
922 923 924 925 926 927 928 929

		ret = 0;
		if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
			ret = -EINVAL;
		else
			q->flags = u;

		return ret;
A
Arnd Bergmann 已提交
930 931

	case TUNGETIFF:
932
		rcu_read_lock_bh();
933
		vlan = rcu_dereference_bh(q->vlan);
934 935 936 937 938
		if (vlan)
			dev_hold(vlan->dev);
		rcu_read_unlock_bh();

		if (!vlan)
A
Arnd Bergmann 已提交
939 940
			return -ENOLINK;

941
		ret = 0;
942
		if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) ||
943
		    put_user(q->flags, &ifr->ifr_flags))
944 945 946
			ret = -EFAULT;
		dev_put(vlan->dev);
		return ret;
A
Arnd Bergmann 已提交
947 948

	case TUNGETFEATURES:
949
		if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
A
Arnd Bergmann 已提交
950 951 952 953 954 955 956 957 958 959
			return -EFAULT;
		return 0;

	case TUNSETSNDBUF:
		if (get_user(u, up))
			return -EFAULT;

		q->sk.sk_sndbuf = u;
		return 0;

960 961 962 963 964 965 966 967 968 969 970 971 972 973 974
	case TUNGETVNETHDRSZ:
		s = q->vnet_hdr_sz;
		if (put_user(s, sp))
			return -EFAULT;
		return 0;

	case TUNSETVNETHDRSZ:
		if (get_user(s, sp))
			return -EFAULT;
		if (s < (int)sizeof(struct virtio_net_hdr))
			return -EINVAL;

		q->vnet_hdr_sz = s;
		return 0;

A
Arnd Bergmann 已提交
975 976 977
	case TUNSETOFFLOAD:
		/* let the user check for future flags */
		if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
978
			    TUN_F_TSO_ECN | TUN_F_UFO))
A
Arnd Bergmann 已提交
979 980
			return -EINVAL;

981 982 983 984
		/* TODO: only accept frames with the features that
			 got enabled for forwarded frames */
		if (!(q->flags & IFF_VNET_HDR))
			return  -EINVAL;
A
Arnd Bergmann 已提交
985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013
		return 0;

	default:
		return -EINVAL;
	}
}

#ifdef CONFIG_COMPAT
static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
				 unsigned long arg)
{
	return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
}
#endif

static const struct file_operations macvtap_fops = {
	.owner		= THIS_MODULE,
	.open		= macvtap_open,
	.release	= macvtap_release,
	.aio_read	= macvtap_aio_read,
	.aio_write	= macvtap_aio_write,
	.poll		= macvtap_poll,
	.llseek		= no_llseek,
	.unlocked_ioctl	= macvtap_ioctl,
#ifdef CONFIG_COMPAT
	.compat_ioctl	= macvtap_compat_ioctl,
#endif
};

1014 1015 1016 1017
static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
			   struct msghdr *m, size_t total_len)
{
	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 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060
			    m->msg_flags & MSG_DONTWAIT);
}

static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
			   struct msghdr *m, size_t total_len,
			   int flags)
{
	struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
	int ret;
	if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
		return -EINVAL;
	ret = macvtap_do_read(q, iocb, m->msg_iov, total_len,
			  flags & MSG_DONTWAIT);
	if (ret > total_len) {
		m->msg_flags |= MSG_TRUNC;
		ret = flags & MSG_TRUNC ? ret : total_len;
	}
	return ret;
}

/* Ops structure to mimic raw sockets with tun */
static const struct proto_ops macvtap_socket_ops = {
	.sendmsg = macvtap_sendmsg,
	.recvmsg = macvtap_recvmsg,
};

/* Get an underlying socket object from tun file.  Returns error unless file is
 * attached to a device.  The returned object works like a packet socket, it
 * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
 * holding a reference to the file for as long as the socket is in use. */
struct socket *macvtap_get_socket(struct file *file)
{
	struct macvtap_queue *q;
	if (file->f_op != &macvtap_fops)
		return ERR_PTR(-EINVAL);
	q = file->private_data;
	if (!q)
		return ERR_PTR(-EBADFD);
	return &q->sock;
}
EXPORT_SYMBOL_GPL(macvtap_get_socket);

1061 1062 1063 1064
static int macvtap_device_event(struct notifier_block *unused,
				unsigned long event, void *ptr)
{
	struct net_device *dev = ptr;
1065
	struct macvlan_dev *vlan;
1066 1067
	struct device *classdev;
	dev_t devt;
1068
	int err;
1069 1070 1071 1072

	if (dev->rtnl_link_ops != &macvtap_link_ops)
		return NOTIFY_DONE;

1073
	vlan = netdev_priv(dev);
1074 1075 1076 1077 1078 1079 1080

	switch (event) {
	case NETDEV_REGISTER:
		/* Create the device node here after the network device has
		 * been registered but before register_netdevice has
		 * finished running.
		 */
1081 1082 1083 1084 1085
		err = macvtap_get_minor(vlan);
		if (err)
			return notifier_from_errno(err);

		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1086 1087
		classdev = device_create(macvtap_class, &dev->dev, devt,
					 dev, "tap%d", dev->ifindex);
1088 1089
		if (IS_ERR(classdev)) {
			macvtap_free_minor(vlan);
1090
			return notifier_from_errno(PTR_ERR(classdev));
1091
		}
1092 1093
		break;
	case NETDEV_UNREGISTER:
1094
		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
1095
		device_destroy(macvtap_class, devt);
1096
		macvtap_free_minor(vlan);
1097 1098 1099 1100 1101 1102 1103 1104 1105 1106
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block macvtap_notifier_block __read_mostly = {
	.notifier_call	= macvtap_device_event,
};

A
Arnd Bergmann 已提交
1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126
static int macvtap_init(void)
{
	int err;

	err = alloc_chrdev_region(&macvtap_major, 0,
				MACVTAP_NUM_DEVS, "macvtap");
	if (err)
		goto out1;

	cdev_init(&macvtap_cdev, &macvtap_fops);
	err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
	if (err)
		goto out2;

	macvtap_class = class_create(THIS_MODULE, "macvtap");
	if (IS_ERR(macvtap_class)) {
		err = PTR_ERR(macvtap_class);
		goto out3;
	}

1127
	err = register_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1128 1129 1130
	if (err)
		goto out4;

1131 1132 1133 1134
	err = macvlan_link_register(&macvtap_link_ops);
	if (err)
		goto out5;

A
Arnd Bergmann 已提交
1135 1136
	return 0;

1137 1138
out5:
	unregister_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152
out4:
	class_unregister(macvtap_class);
out3:
	cdev_del(&macvtap_cdev);
out2:
	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
out1:
	return err;
}
module_init(macvtap_init);

static void macvtap_exit(void)
{
	rtnl_link_unregister(&macvtap_link_ops);
1153
	unregister_netdevice_notifier(&macvtap_notifier_block);
A
Arnd Bergmann 已提交
1154 1155 1156 1157 1158 1159 1160 1161 1162
	class_unregister(macvtap_class);
	cdev_del(&macvtap_cdev);
	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
}
module_exit(macvtap_exit);

MODULE_ALIAS_RTNL_LINK("macvtap");
MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
MODULE_LICENSE("GPL");
反馈
建议
客服 返回
顶部