1 #include <linux/etherdevice.h> 2 #include <linux/if_macvlan.h> 3 #include <linux/if_vlan.h> 4 #include <linux/interrupt.h> 5 #include <linux/nsproxy.h> 6 #include <linux/compat.h> 7 #include <linux/if_tun.h> 8 #include <linux/module.h> 9 #include <linux/skbuff.h> 10 #include <linux/cache.h> 11 #include <linux/sched.h> 12 #include <linux/types.h> 13 #include <linux/slab.h> 14 #include <linux/init.h> 15 #include <linux/wait.h> 16 #include <linux/cdev.h> 17 #include <linux/idr.h> 18 #include <linux/fs.h> 19 20 #include <net/net_namespace.h> 21 #include <net/rtnetlink.h> 22 #include <net/sock.h> 23 #include <linux/virtio_net.h> 24 25 /* 26 * A macvtap queue is the central object of this driver, it connects 27 * an open character device to a macvlan interface. There can be 28 * multiple queues on one interface, which map back to queues 29 * implemented in hardware on the underlying device. 30 * 31 * macvtap_proto is used to allocate queues through the sock allocation 32 * mechanism. 33 * 34 */ 35 struct macvtap_queue { 36 struct sock sk; 37 struct socket sock; 38 struct socket_wq wq; 39 int vnet_hdr_sz; 40 struct macvlan_dev __rcu *vlan; 41 struct file *file; 42 unsigned int flags; 43 u16 queue_index; 44 bool enabled; 45 struct list_head next; 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 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ 69 NETIF_F_TSO6 | NETIF_F_UFO) 70 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) 71 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) 72 73 /* 74 * RCU usage: 75 * The macvtap_queue and the macvlan_dev are loosely coupled, the 76 * pointers from one to the other can only be read while rcu_read_lock 77 * or rtnl is held. 78 * 79 * Both the file and the macvlan_dev hold a reference on the macvtap_queue 80 * through sock_hold(&q->sk). When the macvlan_dev goes away first, 81 * q->vlan becomes inaccessible. When the files gets closed, 82 * macvtap_get_queue() fails. 83 * 84 * There may still be references to the struct sock inside of the 85 * queue from outbound SKBs, but these never reference back to the 86 * file or the dev. The data structure is freed through __sk_free 87 * when both our references and any pending SKBs are gone. 88 */ 89 90 static int macvtap_enable_queue(struct net_device *dev, struct file *file, 91 struct macvtap_queue *q) 92 { 93 struct macvlan_dev *vlan = netdev_priv(dev); 94 int err = -EINVAL; 95 96 ASSERT_RTNL(); 97 98 if (q->enabled) 99 goto out; 100 101 err = 0; 102 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 103 q->queue_index = vlan->numvtaps; 104 q->enabled = true; 105 106 vlan->numvtaps++; 107 out: 108 return err; 109 } 110 111 static int macvtap_set_queue(struct net_device *dev, struct file *file, 112 struct macvtap_queue *q) 113 { 114 struct macvlan_dev *vlan = netdev_priv(dev); 115 int err = -EBUSY; 116 117 rtnl_lock(); 118 if (vlan->numqueues == MAX_MACVTAP_QUEUES) 119 goto out; 120 121 err = 0; 122 rcu_assign_pointer(q->vlan, vlan); 123 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 124 sock_hold(&q->sk); 125 126 q->file = file; 127 q->queue_index = vlan->numvtaps; 128 q->enabled = true; 129 file->private_data = q; 130 list_add_tail(&q->next, &vlan->queue_list); 131 132 vlan->numvtaps++; 133 vlan->numqueues++; 134 135 out: 136 rtnl_unlock(); 137 return err; 138 } 139 140 static int macvtap_disable_queue(struct macvtap_queue *q) 141 { 142 struct macvlan_dev *vlan; 143 struct macvtap_queue *nq; 144 145 ASSERT_RTNL(); 146 if (!q->enabled) 147 return -EINVAL; 148 149 vlan = rtnl_dereference(q->vlan); 150 151 if (vlan) { 152 int index = q->queue_index; 153 BUG_ON(index >= vlan->numvtaps); 154 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]); 155 nq->queue_index = index; 156 157 rcu_assign_pointer(vlan->taps[index], nq); 158 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); 159 q->enabled = false; 160 161 vlan->numvtaps--; 162 } 163 164 return 0; 165 } 166 167 /* 168 * The file owning the queue got closed, give up both 169 * the reference that the files holds as well as the 170 * one from the macvlan_dev if that still exists. 171 * 172 * Using the spinlock makes sure that we don't get 173 * to the queue again after destroying it. 174 */ 175 static void macvtap_put_queue(struct macvtap_queue *q) 176 { 177 struct macvlan_dev *vlan; 178 179 rtnl_lock(); 180 vlan = rtnl_dereference(q->vlan); 181 182 if (vlan) { 183 if (q->enabled) 184 BUG_ON(macvtap_disable_queue(q)); 185 186 vlan->numqueues--; 187 RCU_INIT_POINTER(q->vlan, NULL); 188 sock_put(&q->sk); 189 list_del_init(&q->next); 190 } 191 192 rtnl_unlock(); 193 194 synchronize_rcu(); 195 sock_put(&q->sk); 196 } 197 198 /* 199 * Select a queue based on the rxq of the device on which this packet 200 * arrived. If the incoming device is not mq, calculate a flow hash 201 * to select a queue. If all fails, find the first available queue. 202 * Cache vlan->numvtaps since it can become zero during the execution 203 * of this function. 204 */ 205 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, 206 struct sk_buff *skb) 207 { 208 struct macvlan_dev *vlan = netdev_priv(dev); 209 struct macvtap_queue *tap = NULL; 210 /* Access to taps array is protected by rcu, but access to numvtaps 211 * isn't. Below we use it to lookup a queue, but treat it as a hint 212 * and validate that the result isn't NULL - in case we are 213 * racing against queue removal. 214 */ 215 int numvtaps = ACCESS_ONCE(vlan->numvtaps); 216 __u32 rxq; 217 218 if (!numvtaps) 219 goto out; 220 221 /* Check if we can use flow to select a queue */ 222 rxq = skb_get_rxhash(skb); 223 if (rxq) { 224 tap = rcu_dereference(vlan->taps[rxq % numvtaps]); 225 goto out; 226 } 227 228 if (likely(skb_rx_queue_recorded(skb))) { 229 rxq = skb_get_rx_queue(skb); 230 231 while (unlikely(rxq >= numvtaps)) 232 rxq -= numvtaps; 233 234 tap = rcu_dereference(vlan->taps[rxq]); 235 goto out; 236 } 237 238 tap = rcu_dereference(vlan->taps[0]); 239 out: 240 return tap; 241 } 242 243 /* 244 * The net_device is going away, give up the reference 245 * that it holds on all queues and safely set the pointer 246 * from the queues to NULL. 247 */ 248 static void macvtap_del_queues(struct net_device *dev) 249 { 250 struct macvlan_dev *vlan = netdev_priv(dev); 251 struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES]; 252 int i, j = 0; 253 254 ASSERT_RTNL(); 255 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { 256 list_del_init(&q->next); 257 qlist[j++] = q; 258 RCU_INIT_POINTER(q->vlan, NULL); 259 if (q->enabled) 260 vlan->numvtaps--; 261 vlan->numqueues--; 262 } 263 for (i = 0; i < vlan->numvtaps; i++) 264 RCU_INIT_POINTER(vlan->taps[i], NULL); 265 BUG_ON(vlan->numvtaps); 266 BUG_ON(vlan->numqueues); 267 /* guarantee that any future macvtap_set_queue will fail */ 268 vlan->numvtaps = MAX_MACVTAP_QUEUES; 269 270 for (--j; j >= 0; j--) 271 sock_put(&qlist[j]->sk); 272 } 273 274 /* 275 * Forward happens for data that gets sent from one macvlan 276 * endpoint to another one in bridge mode. We just take 277 * the skb and put it into the receive queue. 278 */ 279 static int macvtap_forward(struct net_device *dev, struct sk_buff *skb) 280 { 281 struct macvlan_dev *vlan = netdev_priv(dev); 282 struct macvtap_queue *q = macvtap_get_queue(dev, skb); 283 netdev_features_t features = TAP_FEATURES; 284 285 if (!q) 286 goto drop; 287 288 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) 289 goto drop; 290 291 skb->dev = dev; 292 /* Apply the forward feature mask so that we perform segmentation 293 * according to users wishes. This only works if VNET_HDR is 294 * enabled. 295 */ 296 if (q->flags & IFF_VNET_HDR) 297 features |= vlan->tap_features; 298 if (netif_needs_gso(skb, features)) { 299 struct sk_buff *segs = __skb_gso_segment(skb, features, false); 300 301 if (IS_ERR(segs)) 302 goto drop; 303 304 if (!segs) { 305 skb_queue_tail(&q->sk.sk_receive_queue, skb); 306 goto wake_up; 307 } 308 309 kfree_skb(skb); 310 while (segs) { 311 struct sk_buff *nskb = segs->next; 312 313 segs->next = NULL; 314 skb_queue_tail(&q->sk.sk_receive_queue, segs); 315 segs = nskb; 316 } 317 } else { 318 skb_queue_tail(&q->sk.sk_receive_queue, skb); 319 } 320 321 wake_up: 322 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); 323 return NET_RX_SUCCESS; 324 325 drop: 326 kfree_skb(skb); 327 return NET_RX_DROP; 328 } 329 330 /* 331 * Receive is for data from the external interface (lowerdev), 332 * in case of macvtap, we can treat that the same way as 333 * forward, which macvlan cannot. 334 */ 335 static int macvtap_receive(struct sk_buff *skb) 336 { 337 skb_push(skb, ETH_HLEN); 338 return macvtap_forward(skb->dev, skb); 339 } 340 341 static int macvtap_get_minor(struct macvlan_dev *vlan) 342 { 343 int retval = -ENOMEM; 344 345 mutex_lock(&minor_lock); 346 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); 347 if (retval >= 0) { 348 vlan->minor = retval; 349 } else if (retval == -ENOSPC) { 350 printk(KERN_ERR "too many macvtap devices\n"); 351 retval = -EINVAL; 352 } 353 mutex_unlock(&minor_lock); 354 return retval < 0 ? retval : 0; 355 } 356 357 static void macvtap_free_minor(struct macvlan_dev *vlan) 358 { 359 mutex_lock(&minor_lock); 360 if (vlan->minor) { 361 idr_remove(&minor_idr, vlan->minor); 362 vlan->minor = 0; 363 } 364 mutex_unlock(&minor_lock); 365 } 366 367 static struct net_device *dev_get_by_macvtap_minor(int minor) 368 { 369 struct net_device *dev = NULL; 370 struct macvlan_dev *vlan; 371 372 mutex_lock(&minor_lock); 373 vlan = idr_find(&minor_idr, minor); 374 if (vlan) { 375 dev = vlan->dev; 376 dev_hold(dev); 377 } 378 mutex_unlock(&minor_lock); 379 return dev; 380 } 381 382 static int macvtap_newlink(struct net *src_net, 383 struct net_device *dev, 384 struct nlattr *tb[], 385 struct nlattr *data[]) 386 { 387 struct macvlan_dev *vlan = netdev_priv(dev); 388 INIT_LIST_HEAD(&vlan->queue_list); 389 390 /* Since macvlan supports all offloads by default, make 391 * tap support all offloads also. 392 */ 393 vlan->tap_features = TUN_OFFLOADS; 394 395 /* Don't put anything that may fail after macvlan_common_newlink 396 * because we can't undo what it does. 397 */ 398 return macvlan_common_newlink(src_net, dev, tb, data, 399 macvtap_receive, macvtap_forward); 400 } 401 402 static void macvtap_dellink(struct net_device *dev, 403 struct list_head *head) 404 { 405 macvtap_del_queues(dev); 406 macvlan_dellink(dev, head); 407 } 408 409 static void macvtap_setup(struct net_device *dev) 410 { 411 macvlan_common_setup(dev); 412 dev->tx_queue_len = TUN_READQ_SIZE; 413 } 414 415 static struct rtnl_link_ops macvtap_link_ops __read_mostly = { 416 .kind = "macvtap", 417 .setup = macvtap_setup, 418 .newlink = macvtap_newlink, 419 .dellink = macvtap_dellink, 420 }; 421 422 423 static void macvtap_sock_write_space(struct sock *sk) 424 { 425 wait_queue_head_t *wqueue; 426 427 if (!sock_writeable(sk) || 428 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 429 return; 430 431 wqueue = sk_sleep(sk); 432 if (wqueue && waitqueue_active(wqueue)) 433 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); 434 } 435 436 static void macvtap_sock_destruct(struct sock *sk) 437 { 438 skb_queue_purge(&sk->sk_receive_queue); 439 } 440 441 static int macvtap_open(struct inode *inode, struct file *file) 442 { 443 struct net *net = current->nsproxy->net_ns; 444 struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode)); 445 struct macvtap_queue *q; 446 int err; 447 448 err = -ENODEV; 449 if (!dev) 450 goto out; 451 452 err = -ENOMEM; 453 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 454 &macvtap_proto); 455 if (!q) 456 goto out; 457 458 RCU_INIT_POINTER(q->sock.wq, &q->wq); 459 init_waitqueue_head(&q->wq.wait); 460 q->sock.type = SOCK_RAW; 461 q->sock.state = SS_CONNECTED; 462 q->sock.file = file; 463 q->sock.ops = &macvtap_socket_ops; 464 sock_init_data(&q->sock, &q->sk); 465 q->sk.sk_write_space = macvtap_sock_write_space; 466 q->sk.sk_destruct = macvtap_sock_destruct; 467 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; 468 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 469 470 /* 471 * so far only KVM virtio_net uses macvtap, enable zero copy between 472 * guest kernel and host kernel when lower device supports zerocopy 473 * 474 * The macvlan supports zerocopy iff the lower device supports zero 475 * copy so we don't have to look at the lower device directly. 476 */ 477 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) 478 sock_set_flag(&q->sk, SOCK_ZEROCOPY); 479 480 err = macvtap_set_queue(dev, file, q); 481 if (err) 482 sock_put(&q->sk); 483 484 out: 485 if (dev) 486 dev_put(dev); 487 488 return err; 489 } 490 491 static int macvtap_release(struct inode *inode, struct file *file) 492 { 493 struct macvtap_queue *q = file->private_data; 494 macvtap_put_queue(q); 495 return 0; 496 } 497 498 static unsigned int macvtap_poll(struct file *file, poll_table * wait) 499 { 500 struct macvtap_queue *q = file->private_data; 501 unsigned int mask = POLLERR; 502 503 if (!q) 504 goto out; 505 506 mask = 0; 507 poll_wait(file, &q->wq.wait, wait); 508 509 if (!skb_queue_empty(&q->sk.sk_receive_queue)) 510 mask |= POLLIN | POLLRDNORM; 511 512 if (sock_writeable(&q->sk) || 513 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && 514 sock_writeable(&q->sk))) 515 mask |= POLLOUT | POLLWRNORM; 516 517 out: 518 return mask; 519 } 520 521 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, 522 size_t len, size_t linear, 523 int noblock, int *err) 524 { 525 struct sk_buff *skb; 526 527 /* Under a page? Don't bother with paged skb. */ 528 if (prepad + len < PAGE_SIZE || !linear) 529 linear = len; 530 531 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 532 err); 533 if (!skb) 534 return NULL; 535 536 skb_reserve(skb, prepad); 537 skb_put(skb, linear); 538 skb->data_len = len - linear; 539 skb->len += len - linear; 540 541 return skb; 542 } 543 544 /* set skb frags from iovec, this can move to core network code for reuse */ 545 static int zerocopy_sg_from_iovec(struct sk_buff *skb, const struct iovec *from, 546 int offset, size_t count) 547 { 548 int len = iov_length(from, count) - offset; 549 int copy = skb_headlen(skb); 550 int size, offset1 = 0; 551 int i = 0; 552 553 /* Skip over from offset */ 554 while (count && (offset >= from->iov_len)) { 555 offset -= from->iov_len; 556 ++from; 557 --count; 558 } 559 560 /* copy up to skb headlen */ 561 while (count && (copy > 0)) { 562 size = min_t(unsigned int, copy, from->iov_len - offset); 563 if (copy_from_user(skb->data + offset1, from->iov_base + offset, 564 size)) 565 return -EFAULT; 566 if (copy > size) { 567 ++from; 568 --count; 569 offset = 0; 570 } else 571 offset += size; 572 copy -= size; 573 offset1 += size; 574 } 575 576 if (len == offset1) 577 return 0; 578 579 while (count--) { 580 struct page *page[MAX_SKB_FRAGS]; 581 int num_pages; 582 unsigned long base; 583 unsigned long truesize; 584 585 len = from->iov_len - offset; 586 if (!len) { 587 offset = 0; 588 ++from; 589 continue; 590 } 591 base = (unsigned long)from->iov_base + offset; 592 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 593 if (i + size > MAX_SKB_FRAGS) 594 return -EMSGSIZE; 595 num_pages = get_user_pages_fast(base, size, 0, &page[i]); 596 if (num_pages != size) { 597 int j; 598 599 for (j = 0; j < num_pages; j++) 600 put_page(page[i + j]); 601 return -EFAULT; 602 } 603 truesize = size * PAGE_SIZE; 604 skb->data_len += len; 605 skb->len += len; 606 skb->truesize += truesize; 607 atomic_add(truesize, &skb->sk->sk_wmem_alloc); 608 while (len) { 609 int off = base & ~PAGE_MASK; 610 int size = min_t(int, len, PAGE_SIZE - off); 611 __skb_fill_page_desc(skb, i, page[i], off, size); 612 skb_shinfo(skb)->nr_frags++; 613 /* increase sk_wmem_alloc */ 614 base += size; 615 len -= size; 616 i++; 617 } 618 offset = 0; 619 ++from; 620 } 621 return 0; 622 } 623 624 /* 625 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should 626 * be shared with the tun/tap driver. 627 */ 628 static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, 629 struct virtio_net_hdr *vnet_hdr) 630 { 631 unsigned short gso_type = 0; 632 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 633 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 634 case VIRTIO_NET_HDR_GSO_TCPV4: 635 gso_type = SKB_GSO_TCPV4; 636 break; 637 case VIRTIO_NET_HDR_GSO_TCPV6: 638 gso_type = SKB_GSO_TCPV6; 639 break; 640 case VIRTIO_NET_HDR_GSO_UDP: 641 gso_type = SKB_GSO_UDP; 642 break; 643 default: 644 return -EINVAL; 645 } 646 647 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) 648 gso_type |= SKB_GSO_TCP_ECN; 649 650 if (vnet_hdr->gso_size == 0) 651 return -EINVAL; 652 } 653 654 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 655 if (!skb_partial_csum_set(skb, vnet_hdr->csum_start, 656 vnet_hdr->csum_offset)) 657 return -EINVAL; 658 } 659 660 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 661 skb_shinfo(skb)->gso_size = vnet_hdr->gso_size; 662 skb_shinfo(skb)->gso_type = gso_type; 663 664 /* Header must be checked, and gso_segs computed. */ 665 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 666 skb_shinfo(skb)->gso_segs = 0; 667 } 668 return 0; 669 } 670 671 static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, 672 struct virtio_net_hdr *vnet_hdr) 673 { 674 memset(vnet_hdr, 0, sizeof(*vnet_hdr)); 675 676 if (skb_is_gso(skb)) { 677 struct skb_shared_info *sinfo = skb_shinfo(skb); 678 679 /* This is a hint as to how much should be linear. */ 680 vnet_hdr->hdr_len = skb_headlen(skb); 681 vnet_hdr->gso_size = sinfo->gso_size; 682 if (sinfo->gso_type & SKB_GSO_TCPV4) 683 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 684 else if (sinfo->gso_type & SKB_GSO_TCPV6) 685 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 686 else if (sinfo->gso_type & SKB_GSO_UDP) 687 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; 688 else 689 BUG(); 690 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 691 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 692 } else 693 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 694 695 if (skb->ip_summed == CHECKSUM_PARTIAL) { 696 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 697 vnet_hdr->csum_start = skb_checksum_start_offset(skb); 698 vnet_hdr->csum_offset = skb->csum_offset; 699 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 700 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; 701 } /* else everything is zero */ 702 703 return 0; 704 } 705 706 static unsigned long iov_pages(const struct iovec *iv, int offset, 707 unsigned long nr_segs) 708 { 709 unsigned long seg, base; 710 int pages = 0, len, size; 711 712 while (nr_segs && (offset >= iv->iov_len)) { 713 offset -= iv->iov_len; 714 ++iv; 715 --nr_segs; 716 } 717 718 for (seg = 0; seg < nr_segs; seg++) { 719 base = (unsigned long)iv[seg].iov_base + offset; 720 len = iv[seg].iov_len - offset; 721 size = ((base & ~PAGE_MASK) + len + ~PAGE_MASK) >> PAGE_SHIFT; 722 pages += size; 723 offset = 0; 724 } 725 726 return pages; 727 } 728 729 /* Get packet from user space buffer */ 730 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 731 const struct iovec *iv, unsigned long total_len, 732 size_t count, int noblock) 733 { 734 struct sk_buff *skb; 735 struct macvlan_dev *vlan; 736 unsigned long len = total_len; 737 int err; 738 struct virtio_net_hdr vnet_hdr = { 0 }; 739 int vnet_hdr_len = 0; 740 int copylen = 0; 741 bool zerocopy = false; 742 size_t linear; 743 744 if (q->flags & IFF_VNET_HDR) { 745 vnet_hdr_len = q->vnet_hdr_sz; 746 747 err = -EINVAL; 748 if (len < vnet_hdr_len) 749 goto err; 750 len -= vnet_hdr_len; 751 752 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0, 753 sizeof(vnet_hdr)); 754 if (err < 0) 755 goto err; 756 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 757 vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 > 758 vnet_hdr.hdr_len) 759 vnet_hdr.hdr_len = vnet_hdr.csum_start + 760 vnet_hdr.csum_offset + 2; 761 err = -EINVAL; 762 if (vnet_hdr.hdr_len > len) 763 goto err; 764 } 765 766 err = -EINVAL; 767 if (unlikely(len < ETH_HLEN)) 768 goto err; 769 770 err = -EMSGSIZE; 771 if (unlikely(count > UIO_MAXIOV)) 772 goto err; 773 774 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { 775 copylen = vnet_hdr.hdr_len ? vnet_hdr.hdr_len : GOODCOPY_LEN; 776 linear = copylen; 777 if (iov_pages(iv, vnet_hdr_len + copylen, count) 778 <= MAX_SKB_FRAGS) 779 zerocopy = true; 780 } 781 782 if (!zerocopy) { 783 copylen = len; 784 linear = vnet_hdr.hdr_len; 785 } 786 787 skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, 788 linear, noblock, &err); 789 if (!skb) 790 goto err; 791 792 if (zerocopy) 793 err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count); 794 else { 795 err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, 796 len); 797 if (!err && m && m->msg_control) { 798 struct ubuf_info *uarg = m->msg_control; 799 uarg->callback(uarg, false); 800 } 801 } 802 803 if (err) 804 goto err_kfree; 805 806 skb_set_network_header(skb, ETH_HLEN); 807 skb_reset_mac_header(skb); 808 skb->protocol = eth_hdr(skb)->h_proto; 809 810 if (vnet_hdr_len) { 811 err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr); 812 if (err) 813 goto err_kfree; 814 } 815 816 skb_probe_transport_header(skb, ETH_HLEN); 817 818 rcu_read_lock(); 819 vlan = rcu_dereference(q->vlan); 820 /* copy skb_ubuf_info for callback when skb has no error */ 821 if (zerocopy) { 822 skb_shinfo(skb)->destructor_arg = m->msg_control; 823 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 824 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 825 } 826 if (vlan) { 827 local_bh_disable(); 828 macvlan_start_xmit(skb, vlan->dev); 829 local_bh_enable(); 830 } else { 831 kfree_skb(skb); 832 } 833 rcu_read_unlock(); 834 835 return total_len; 836 837 err_kfree: 838 kfree_skb(skb); 839 840 err: 841 rcu_read_lock(); 842 vlan = rcu_dereference(q->vlan); 843 if (vlan) 844 vlan->dev->stats.tx_dropped++; 845 rcu_read_unlock(); 846 847 return err; 848 } 849 850 static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv, 851 unsigned long count, loff_t pos) 852 { 853 struct file *file = iocb->ki_filp; 854 ssize_t result = -ENOLINK; 855 struct macvtap_queue *q = file->private_data; 856 857 result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count, 858 file->f_flags & O_NONBLOCK); 859 return result; 860 } 861 862 /* Put packet to the user space buffer */ 863 static ssize_t macvtap_put_user(struct macvtap_queue *q, 864 const struct sk_buff *skb, 865 const struct iovec *iv, int len) 866 { 867 struct macvlan_dev *vlan; 868 int ret; 869 int vnet_hdr_len = 0; 870 int vlan_offset = 0; 871 int copied; 872 873 if (q->flags & IFF_VNET_HDR) { 874 struct virtio_net_hdr vnet_hdr; 875 vnet_hdr_len = q->vnet_hdr_sz; 876 if ((len -= vnet_hdr_len) < 0) 877 return -EINVAL; 878 879 ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr); 880 if (ret) 881 return ret; 882 883 if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) 884 return -EFAULT; 885 } 886 copied = vnet_hdr_len; 887 888 if (!vlan_tx_tag_present(skb)) 889 len = min_t(int, skb->len, len); 890 else { 891 int copy; 892 struct { 893 __be16 h_vlan_proto; 894 __be16 h_vlan_TCI; 895 } veth; 896 veth.h_vlan_proto = skb->vlan_proto; 897 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 898 899 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 900 len = min_t(int, skb->len + VLAN_HLEN, len); 901 902 copy = min_t(int, vlan_offset, len); 903 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 904 len -= copy; 905 copied += copy; 906 if (ret || !len) 907 goto done; 908 909 copy = min_t(int, sizeof(veth), len); 910 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 911 len -= copy; 912 copied += copy; 913 if (ret || !len) 914 goto done; 915 } 916 917 ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 918 copied += len; 919 920 done: 921 rcu_read_lock(); 922 vlan = rcu_dereference(q->vlan); 923 if (vlan) { 924 preempt_disable(); 925 macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0); 926 preempt_enable(); 927 } 928 rcu_read_unlock(); 929 930 return ret ? ret : copied; 931 } 932 933 static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, 934 const struct iovec *iv, unsigned long len, 935 int noblock) 936 { 937 DEFINE_WAIT(wait); 938 struct sk_buff *skb; 939 ssize_t ret = 0; 940 941 while (len) { 942 if (!noblock) 943 prepare_to_wait(sk_sleep(&q->sk), &wait, 944 TASK_INTERRUPTIBLE); 945 946 /* Read frames from the queue */ 947 skb = skb_dequeue(&q->sk.sk_receive_queue); 948 if (!skb) { 949 if (noblock) { 950 ret = -EAGAIN; 951 break; 952 } 953 if (signal_pending(current)) { 954 ret = -ERESTARTSYS; 955 break; 956 } 957 /* Nothing to read, let's sleep */ 958 schedule(); 959 continue; 960 } 961 ret = macvtap_put_user(q, skb, iv, len); 962 kfree_skb(skb); 963 break; 964 } 965 966 if (!noblock) 967 finish_wait(sk_sleep(&q->sk), &wait); 968 return ret; 969 } 970 971 static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, 972 unsigned long count, loff_t pos) 973 { 974 struct file *file = iocb->ki_filp; 975 struct macvtap_queue *q = file->private_data; 976 ssize_t len, ret = 0; 977 978 len = iov_length(iv, count); 979 if (len < 0) { 980 ret = -EINVAL; 981 goto out; 982 } 983 984 ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK); 985 ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */ 986 out: 987 return ret; 988 } 989 990 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) 991 { 992 struct macvlan_dev *vlan; 993 994 ASSERT_RTNL(); 995 vlan = rtnl_dereference(q->vlan); 996 if (vlan) 997 dev_hold(vlan->dev); 998 999 return vlan; 1000 } 1001 1002 static void macvtap_put_vlan(struct macvlan_dev *vlan) 1003 { 1004 dev_put(vlan->dev); 1005 } 1006 1007 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) 1008 { 1009 struct macvtap_queue *q = file->private_data; 1010 struct macvlan_dev *vlan; 1011 int ret; 1012 1013 vlan = macvtap_get_vlan(q); 1014 if (!vlan) 1015 return -EINVAL; 1016 1017 if (flags & IFF_ATTACH_QUEUE) 1018 ret = macvtap_enable_queue(vlan->dev, file, q); 1019 else if (flags & IFF_DETACH_QUEUE) 1020 ret = macvtap_disable_queue(q); 1021 else 1022 ret = -EINVAL; 1023 1024 macvtap_put_vlan(vlan); 1025 return ret; 1026 } 1027 1028 static int set_offload(struct macvtap_queue *q, unsigned long arg) 1029 { 1030 struct macvlan_dev *vlan; 1031 netdev_features_t features; 1032 netdev_features_t feature_mask = 0; 1033 1034 vlan = rtnl_dereference(q->vlan); 1035 if (!vlan) 1036 return -ENOLINK; 1037 1038 features = vlan->dev->features; 1039 1040 if (arg & TUN_F_CSUM) { 1041 feature_mask = NETIF_F_HW_CSUM; 1042 1043 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { 1044 if (arg & TUN_F_TSO_ECN) 1045 feature_mask |= NETIF_F_TSO_ECN; 1046 if (arg & TUN_F_TSO4) 1047 feature_mask |= NETIF_F_TSO; 1048 if (arg & TUN_F_TSO6) 1049 feature_mask |= NETIF_F_TSO6; 1050 } 1051 1052 if (arg & TUN_F_UFO) 1053 feature_mask |= NETIF_F_UFO; 1054 } 1055 1056 /* tun/tap driver inverts the usage for TSO offloads, where 1057 * setting the TSO bit means that the userspace wants to 1058 * accept TSO frames and turning it off means that user space 1059 * does not support TSO. 1060 * For macvtap, we have to invert it to mean the same thing. 1061 * When user space turns off TSO, we turn off GSO/LRO so that 1062 * user-space will not receive TSO frames. 1063 */ 1064 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) 1065 features |= RX_OFFLOADS; 1066 else 1067 features &= ~RX_OFFLOADS; 1068 1069 /* tap_features are the same as features on tun/tap and 1070 * reflect user expectations. 1071 */ 1072 vlan->tap_features = feature_mask; 1073 vlan->set_features = features; 1074 netdev_update_features(vlan->dev); 1075 1076 return 0; 1077 } 1078 1079 /* 1080 * provide compatibility with generic tun/tap interface 1081 */ 1082 static long macvtap_ioctl(struct file *file, unsigned int cmd, 1083 unsigned long arg) 1084 { 1085 struct macvtap_queue *q = file->private_data; 1086 struct macvlan_dev *vlan; 1087 void __user *argp = (void __user *)arg; 1088 struct ifreq __user *ifr = argp; 1089 unsigned int __user *up = argp; 1090 unsigned int u; 1091 int __user *sp = argp; 1092 int s; 1093 int ret; 1094 1095 switch (cmd) { 1096 case TUNSETIFF: 1097 /* ignore the name, just look at flags */ 1098 if (get_user(u, &ifr->ifr_flags)) 1099 return -EFAULT; 1100 1101 ret = 0; 1102 if ((u & ~(IFF_VNET_HDR | IFF_MULTI_QUEUE)) != 1103 (IFF_NO_PI | IFF_TAP)) 1104 ret = -EINVAL; 1105 else 1106 q->flags = u; 1107 1108 return ret; 1109 1110 case TUNGETIFF: 1111 rtnl_lock(); 1112 vlan = macvtap_get_vlan(q); 1113 if (!vlan) { 1114 rtnl_unlock(); 1115 return -ENOLINK; 1116 } 1117 1118 ret = 0; 1119 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1120 put_user(q->flags, &ifr->ifr_flags)) 1121 ret = -EFAULT; 1122 macvtap_put_vlan(vlan); 1123 rtnl_unlock(); 1124 return ret; 1125 1126 case TUNSETQUEUE: 1127 if (get_user(u, &ifr->ifr_flags)) 1128 return -EFAULT; 1129 rtnl_lock(); 1130 ret = macvtap_ioctl_set_queue(file, u); 1131 rtnl_unlock(); 1132 return ret; 1133 1134 case TUNGETFEATURES: 1135 if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | 1136 IFF_MULTI_QUEUE, up)) 1137 return -EFAULT; 1138 return 0; 1139 1140 case TUNSETSNDBUF: 1141 if (get_user(u, up)) 1142 return -EFAULT; 1143 1144 q->sk.sk_sndbuf = u; 1145 return 0; 1146 1147 case TUNGETVNETHDRSZ: 1148 s = q->vnet_hdr_sz; 1149 if (put_user(s, sp)) 1150 return -EFAULT; 1151 return 0; 1152 1153 case TUNSETVNETHDRSZ: 1154 if (get_user(s, sp)) 1155 return -EFAULT; 1156 if (s < (int)sizeof(struct virtio_net_hdr)) 1157 return -EINVAL; 1158 1159 q->vnet_hdr_sz = s; 1160 return 0; 1161 1162 case TUNSETOFFLOAD: 1163 /* let the user check for future flags */ 1164 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 1165 TUN_F_TSO_ECN | TUN_F_UFO)) 1166 return -EINVAL; 1167 1168 rtnl_lock(); 1169 ret = set_offload(q, arg); 1170 rtnl_unlock(); 1171 return ret; 1172 1173 default: 1174 return -EINVAL; 1175 } 1176 } 1177 1178 #ifdef CONFIG_COMPAT 1179 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, 1180 unsigned long arg) 1181 { 1182 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1183 } 1184 #endif 1185 1186 static const struct file_operations macvtap_fops = { 1187 .owner = THIS_MODULE, 1188 .open = macvtap_open, 1189 .release = macvtap_release, 1190 .aio_read = macvtap_aio_read, 1191 .aio_write = macvtap_aio_write, 1192 .poll = macvtap_poll, 1193 .llseek = no_llseek, 1194 .unlocked_ioctl = macvtap_ioctl, 1195 #ifdef CONFIG_COMPAT 1196 .compat_ioctl = macvtap_compat_ioctl, 1197 #endif 1198 }; 1199 1200 static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, 1201 struct msghdr *m, size_t total_len) 1202 { 1203 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1204 return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen, 1205 m->msg_flags & MSG_DONTWAIT); 1206 } 1207 1208 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, 1209 struct msghdr *m, size_t total_len, 1210 int flags) 1211 { 1212 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1213 int ret; 1214 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1215 return -EINVAL; 1216 ret = macvtap_do_read(q, iocb, m->msg_iov, total_len, 1217 flags & MSG_DONTWAIT); 1218 if (ret > total_len) { 1219 m->msg_flags |= MSG_TRUNC; 1220 ret = flags & MSG_TRUNC ? ret : total_len; 1221 } 1222 return ret; 1223 } 1224 1225 /* Ops structure to mimic raw sockets with tun */ 1226 static const struct proto_ops macvtap_socket_ops = { 1227 .sendmsg = macvtap_sendmsg, 1228 .recvmsg = macvtap_recvmsg, 1229 }; 1230 1231 /* Get an underlying socket object from tun file. Returns error unless file is 1232 * attached to a device. The returned object works like a packet socket, it 1233 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1234 * holding a reference to the file for as long as the socket is in use. */ 1235 struct socket *macvtap_get_socket(struct file *file) 1236 { 1237 struct macvtap_queue *q; 1238 if (file->f_op != &macvtap_fops) 1239 return ERR_PTR(-EINVAL); 1240 q = file->private_data; 1241 if (!q) 1242 return ERR_PTR(-EBADFD); 1243 return &q->sock; 1244 } 1245 EXPORT_SYMBOL_GPL(macvtap_get_socket); 1246 1247 static int macvtap_device_event(struct notifier_block *unused, 1248 unsigned long event, void *ptr) 1249 { 1250 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1251 struct macvlan_dev *vlan; 1252 struct device *classdev; 1253 dev_t devt; 1254 int err; 1255 1256 if (dev->rtnl_link_ops != &macvtap_link_ops) 1257 return NOTIFY_DONE; 1258 1259 vlan = netdev_priv(dev); 1260 1261 switch (event) { 1262 case NETDEV_REGISTER: 1263 /* Create the device node here after the network device has 1264 * been registered but before register_netdevice has 1265 * finished running. 1266 */ 1267 err = macvtap_get_minor(vlan); 1268 if (err) 1269 return notifier_from_errno(err); 1270 1271 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1272 classdev = device_create(macvtap_class, &dev->dev, devt, 1273 dev, "tap%d", dev->ifindex); 1274 if (IS_ERR(classdev)) { 1275 macvtap_free_minor(vlan); 1276 return notifier_from_errno(PTR_ERR(classdev)); 1277 } 1278 break; 1279 case NETDEV_UNREGISTER: 1280 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1281 device_destroy(macvtap_class, devt); 1282 macvtap_free_minor(vlan); 1283 break; 1284 } 1285 1286 return NOTIFY_DONE; 1287 } 1288 1289 static struct notifier_block macvtap_notifier_block __read_mostly = { 1290 .notifier_call = macvtap_device_event, 1291 }; 1292 1293 static int macvtap_init(void) 1294 { 1295 int err; 1296 1297 err = alloc_chrdev_region(&macvtap_major, 0, 1298 MACVTAP_NUM_DEVS, "macvtap"); 1299 if (err) 1300 goto out1; 1301 1302 cdev_init(&macvtap_cdev, &macvtap_fops); 1303 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); 1304 if (err) 1305 goto out2; 1306 1307 macvtap_class = class_create(THIS_MODULE, "macvtap"); 1308 if (IS_ERR(macvtap_class)) { 1309 err = PTR_ERR(macvtap_class); 1310 goto out3; 1311 } 1312 1313 err = register_netdevice_notifier(&macvtap_notifier_block); 1314 if (err) 1315 goto out4; 1316 1317 err = macvlan_link_register(&macvtap_link_ops); 1318 if (err) 1319 goto out5; 1320 1321 return 0; 1322 1323 out5: 1324 unregister_netdevice_notifier(&macvtap_notifier_block); 1325 out4: 1326 class_unregister(macvtap_class); 1327 out3: 1328 cdev_del(&macvtap_cdev); 1329 out2: 1330 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1331 out1: 1332 return err; 1333 } 1334 module_init(macvtap_init); 1335 1336 static void macvtap_exit(void) 1337 { 1338 rtnl_link_unregister(&macvtap_link_ops); 1339 unregister_netdevice_notifier(&macvtap_notifier_block); 1340 class_unregister(macvtap_class); 1341 cdev_del(&macvtap_cdev); 1342 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1343 } 1344 module_exit(macvtap_exit); 1345 1346 MODULE_ALIAS_RTNL_LINK("macvtap"); 1347 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 1348 MODULE_LICENSE("GPL"); 1349