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