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, 0); 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 /* 545 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should 546 * be shared with the tun/tap driver. 547 */ 548 static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, 549 struct virtio_net_hdr *vnet_hdr) 550 { 551 unsigned short gso_type = 0; 552 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 553 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 554 case VIRTIO_NET_HDR_GSO_TCPV4: 555 gso_type = SKB_GSO_TCPV4; 556 break; 557 case VIRTIO_NET_HDR_GSO_TCPV6: 558 gso_type = SKB_GSO_TCPV6; 559 break; 560 case VIRTIO_NET_HDR_GSO_UDP: 561 gso_type = SKB_GSO_UDP; 562 break; 563 default: 564 return -EINVAL; 565 } 566 567 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) 568 gso_type |= SKB_GSO_TCP_ECN; 569 570 if (vnet_hdr->gso_size == 0) 571 return -EINVAL; 572 } 573 574 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 575 if (!skb_partial_csum_set(skb, vnet_hdr->csum_start, 576 vnet_hdr->csum_offset)) 577 return -EINVAL; 578 } 579 580 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 581 skb_shinfo(skb)->gso_size = vnet_hdr->gso_size; 582 skb_shinfo(skb)->gso_type = gso_type; 583 584 /* Header must be checked, and gso_segs computed. */ 585 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 586 skb_shinfo(skb)->gso_segs = 0; 587 } 588 return 0; 589 } 590 591 static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, 592 struct virtio_net_hdr *vnet_hdr) 593 { 594 memset(vnet_hdr, 0, sizeof(*vnet_hdr)); 595 596 if (skb_is_gso(skb)) { 597 struct skb_shared_info *sinfo = skb_shinfo(skb); 598 599 /* This is a hint as to how much should be linear. */ 600 vnet_hdr->hdr_len = skb_headlen(skb); 601 vnet_hdr->gso_size = sinfo->gso_size; 602 if (sinfo->gso_type & SKB_GSO_TCPV4) 603 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 604 else if (sinfo->gso_type & SKB_GSO_TCPV6) 605 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 606 else if (sinfo->gso_type & SKB_GSO_UDP) 607 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; 608 else 609 BUG(); 610 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 611 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 612 } else 613 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 614 615 if (skb->ip_summed == CHECKSUM_PARTIAL) { 616 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 617 vnet_hdr->csum_start = skb_checksum_start_offset(skb); 618 vnet_hdr->csum_offset = skb->csum_offset; 619 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 620 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; 621 } /* else everything is zero */ 622 623 return 0; 624 } 625 626 /* Get packet from user space buffer */ 627 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 628 const struct iovec *iv, unsigned long total_len, 629 size_t count, int noblock) 630 { 631 struct sk_buff *skb; 632 struct macvlan_dev *vlan; 633 unsigned long len = total_len; 634 int err; 635 struct virtio_net_hdr vnet_hdr = { 0 }; 636 int vnet_hdr_len = 0; 637 int copylen = 0; 638 bool zerocopy = false; 639 size_t linear; 640 641 if (q->flags & IFF_VNET_HDR) { 642 vnet_hdr_len = q->vnet_hdr_sz; 643 644 err = -EINVAL; 645 if (len < vnet_hdr_len) 646 goto err; 647 len -= vnet_hdr_len; 648 649 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0, 650 sizeof(vnet_hdr)); 651 if (err < 0) 652 goto err; 653 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 654 vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 > 655 vnet_hdr.hdr_len) 656 vnet_hdr.hdr_len = vnet_hdr.csum_start + 657 vnet_hdr.csum_offset + 2; 658 err = -EINVAL; 659 if (vnet_hdr.hdr_len > len) 660 goto err; 661 } 662 663 err = -EINVAL; 664 if (unlikely(len < ETH_HLEN)) 665 goto err; 666 667 err = -EMSGSIZE; 668 if (unlikely(count > UIO_MAXIOV)) 669 goto err; 670 671 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { 672 copylen = vnet_hdr.hdr_len ? vnet_hdr.hdr_len : GOODCOPY_LEN; 673 linear = copylen; 674 if (iov_pages(iv, vnet_hdr_len + copylen, count) 675 <= MAX_SKB_FRAGS) 676 zerocopy = true; 677 } 678 679 if (!zerocopy) { 680 copylen = len; 681 linear = vnet_hdr.hdr_len; 682 } 683 684 skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, 685 linear, noblock, &err); 686 if (!skb) 687 goto err; 688 689 if (zerocopy) 690 err = zerocopy_sg_from_iovec(skb, iv, vnet_hdr_len, count); 691 else { 692 err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, 693 len); 694 if (!err && m && m->msg_control) { 695 struct ubuf_info *uarg = m->msg_control; 696 uarg->callback(uarg, false); 697 } 698 } 699 700 if (err) 701 goto err_kfree; 702 703 skb_set_network_header(skb, ETH_HLEN); 704 skb_reset_mac_header(skb); 705 skb->protocol = eth_hdr(skb)->h_proto; 706 707 if (vnet_hdr_len) { 708 err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr); 709 if (err) 710 goto err_kfree; 711 } 712 713 skb_probe_transport_header(skb, ETH_HLEN); 714 715 rcu_read_lock(); 716 vlan = rcu_dereference(q->vlan); 717 /* copy skb_ubuf_info for callback when skb has no error */ 718 if (zerocopy) { 719 skb_shinfo(skb)->destructor_arg = m->msg_control; 720 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 721 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 722 } 723 if (vlan) { 724 local_bh_disable(); 725 macvlan_start_xmit(skb, vlan->dev); 726 local_bh_enable(); 727 } else { 728 kfree_skb(skb); 729 } 730 rcu_read_unlock(); 731 732 return total_len; 733 734 err_kfree: 735 kfree_skb(skb); 736 737 err: 738 rcu_read_lock(); 739 vlan = rcu_dereference(q->vlan); 740 if (vlan) 741 vlan->dev->stats.tx_dropped++; 742 rcu_read_unlock(); 743 744 return err; 745 } 746 747 static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv, 748 unsigned long count, loff_t pos) 749 { 750 struct file *file = iocb->ki_filp; 751 ssize_t result = -ENOLINK; 752 struct macvtap_queue *q = file->private_data; 753 754 result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count, 755 file->f_flags & O_NONBLOCK); 756 return result; 757 } 758 759 /* Put packet to the user space buffer */ 760 static ssize_t macvtap_put_user(struct macvtap_queue *q, 761 const struct sk_buff *skb, 762 const struct iovec *iv, int len) 763 { 764 struct macvlan_dev *vlan; 765 int ret; 766 int vnet_hdr_len = 0; 767 int vlan_offset = 0; 768 int copied; 769 770 if (q->flags & IFF_VNET_HDR) { 771 struct virtio_net_hdr vnet_hdr; 772 vnet_hdr_len = q->vnet_hdr_sz; 773 if ((len -= vnet_hdr_len) < 0) 774 return -EINVAL; 775 776 ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr); 777 if (ret) 778 return ret; 779 780 if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) 781 return -EFAULT; 782 } 783 copied = vnet_hdr_len; 784 785 if (!vlan_tx_tag_present(skb)) 786 len = min_t(int, skb->len, len); 787 else { 788 int copy; 789 struct { 790 __be16 h_vlan_proto; 791 __be16 h_vlan_TCI; 792 } veth; 793 veth.h_vlan_proto = skb->vlan_proto; 794 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 795 796 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 797 len = min_t(int, skb->len + VLAN_HLEN, len); 798 799 copy = min_t(int, vlan_offset, len); 800 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 801 len -= copy; 802 copied += copy; 803 if (ret || !len) 804 goto done; 805 806 copy = min_t(int, sizeof(veth), len); 807 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 808 len -= copy; 809 copied += copy; 810 if (ret || !len) 811 goto done; 812 } 813 814 ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 815 copied += len; 816 817 done: 818 rcu_read_lock(); 819 vlan = rcu_dereference(q->vlan); 820 if (vlan) { 821 preempt_disable(); 822 macvlan_count_rx(vlan, copied - vnet_hdr_len, ret == 0, 0); 823 preempt_enable(); 824 } 825 rcu_read_unlock(); 826 827 return ret ? ret : copied; 828 } 829 830 static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb, 831 const struct iovec *iv, unsigned long len, 832 int noblock) 833 { 834 DEFINE_WAIT(wait); 835 struct sk_buff *skb; 836 ssize_t ret = 0; 837 838 while (len) { 839 if (!noblock) 840 prepare_to_wait(sk_sleep(&q->sk), &wait, 841 TASK_INTERRUPTIBLE); 842 843 /* Read frames from the queue */ 844 skb = skb_dequeue(&q->sk.sk_receive_queue); 845 if (!skb) { 846 if (noblock) { 847 ret = -EAGAIN; 848 break; 849 } 850 if (signal_pending(current)) { 851 ret = -ERESTARTSYS; 852 break; 853 } 854 /* Nothing to read, let's sleep */ 855 schedule(); 856 continue; 857 } 858 ret = macvtap_put_user(q, skb, iv, len); 859 kfree_skb(skb); 860 break; 861 } 862 863 if (!noblock) 864 finish_wait(sk_sleep(&q->sk), &wait); 865 return ret; 866 } 867 868 static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, 869 unsigned long count, loff_t pos) 870 { 871 struct file *file = iocb->ki_filp; 872 struct macvtap_queue *q = file->private_data; 873 ssize_t len, ret = 0; 874 875 len = iov_length(iv, count); 876 if (len < 0) { 877 ret = -EINVAL; 878 goto out; 879 } 880 881 ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK); 882 ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */ 883 out: 884 return ret; 885 } 886 887 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) 888 { 889 struct macvlan_dev *vlan; 890 891 ASSERT_RTNL(); 892 vlan = rtnl_dereference(q->vlan); 893 if (vlan) 894 dev_hold(vlan->dev); 895 896 return vlan; 897 } 898 899 static void macvtap_put_vlan(struct macvlan_dev *vlan) 900 { 901 dev_put(vlan->dev); 902 } 903 904 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) 905 { 906 struct macvtap_queue *q = file->private_data; 907 struct macvlan_dev *vlan; 908 int ret; 909 910 vlan = macvtap_get_vlan(q); 911 if (!vlan) 912 return -EINVAL; 913 914 if (flags & IFF_ATTACH_QUEUE) 915 ret = macvtap_enable_queue(vlan->dev, file, q); 916 else if (flags & IFF_DETACH_QUEUE) 917 ret = macvtap_disable_queue(q); 918 else 919 ret = -EINVAL; 920 921 macvtap_put_vlan(vlan); 922 return ret; 923 } 924 925 static int set_offload(struct macvtap_queue *q, unsigned long arg) 926 { 927 struct macvlan_dev *vlan; 928 netdev_features_t features; 929 netdev_features_t feature_mask = 0; 930 931 vlan = rtnl_dereference(q->vlan); 932 if (!vlan) 933 return -ENOLINK; 934 935 features = vlan->dev->features; 936 937 if (arg & TUN_F_CSUM) { 938 feature_mask = NETIF_F_HW_CSUM; 939 940 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { 941 if (arg & TUN_F_TSO_ECN) 942 feature_mask |= NETIF_F_TSO_ECN; 943 if (arg & TUN_F_TSO4) 944 feature_mask |= NETIF_F_TSO; 945 if (arg & TUN_F_TSO6) 946 feature_mask |= NETIF_F_TSO6; 947 } 948 949 if (arg & TUN_F_UFO) 950 feature_mask |= NETIF_F_UFO; 951 } 952 953 /* tun/tap driver inverts the usage for TSO offloads, where 954 * setting the TSO bit means that the userspace wants to 955 * accept TSO frames and turning it off means that user space 956 * does not support TSO. 957 * For macvtap, we have to invert it to mean the same thing. 958 * When user space turns off TSO, we turn off GSO/LRO so that 959 * user-space will not receive TSO frames. 960 */ 961 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) 962 features |= RX_OFFLOADS; 963 else 964 features &= ~RX_OFFLOADS; 965 966 /* tap_features are the same as features on tun/tap and 967 * reflect user expectations. 968 */ 969 vlan->tap_features = feature_mask; 970 vlan->set_features = features; 971 netdev_update_features(vlan->dev); 972 973 return 0; 974 } 975 976 /* 977 * provide compatibility with generic tun/tap interface 978 */ 979 static long macvtap_ioctl(struct file *file, unsigned int cmd, 980 unsigned long arg) 981 { 982 struct macvtap_queue *q = file->private_data; 983 struct macvlan_dev *vlan; 984 void __user *argp = (void __user *)arg; 985 struct ifreq __user *ifr = argp; 986 unsigned int __user *up = argp; 987 unsigned int u; 988 int __user *sp = argp; 989 int s; 990 int ret; 991 992 switch (cmd) { 993 case TUNSETIFF: 994 /* ignore the name, just look at flags */ 995 if (get_user(u, &ifr->ifr_flags)) 996 return -EFAULT; 997 998 ret = 0; 999 if ((u & ~(IFF_VNET_HDR | IFF_MULTI_QUEUE)) != 1000 (IFF_NO_PI | IFF_TAP)) 1001 ret = -EINVAL; 1002 else 1003 q->flags = u; 1004 1005 return ret; 1006 1007 case TUNGETIFF: 1008 rtnl_lock(); 1009 vlan = macvtap_get_vlan(q); 1010 if (!vlan) { 1011 rtnl_unlock(); 1012 return -ENOLINK; 1013 } 1014 1015 ret = 0; 1016 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1017 put_user(q->flags, &ifr->ifr_flags)) 1018 ret = -EFAULT; 1019 macvtap_put_vlan(vlan); 1020 rtnl_unlock(); 1021 return ret; 1022 1023 case TUNSETQUEUE: 1024 if (get_user(u, &ifr->ifr_flags)) 1025 return -EFAULT; 1026 rtnl_lock(); 1027 ret = macvtap_ioctl_set_queue(file, u); 1028 rtnl_unlock(); 1029 return ret; 1030 1031 case TUNGETFEATURES: 1032 if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | 1033 IFF_MULTI_QUEUE, up)) 1034 return -EFAULT; 1035 return 0; 1036 1037 case TUNSETSNDBUF: 1038 if (get_user(u, up)) 1039 return -EFAULT; 1040 1041 q->sk.sk_sndbuf = u; 1042 return 0; 1043 1044 case TUNGETVNETHDRSZ: 1045 s = q->vnet_hdr_sz; 1046 if (put_user(s, sp)) 1047 return -EFAULT; 1048 return 0; 1049 1050 case TUNSETVNETHDRSZ: 1051 if (get_user(s, sp)) 1052 return -EFAULT; 1053 if (s < (int)sizeof(struct virtio_net_hdr)) 1054 return -EINVAL; 1055 1056 q->vnet_hdr_sz = s; 1057 return 0; 1058 1059 case TUNSETOFFLOAD: 1060 /* let the user check for future flags */ 1061 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 1062 TUN_F_TSO_ECN | TUN_F_UFO)) 1063 return -EINVAL; 1064 1065 rtnl_lock(); 1066 ret = set_offload(q, arg); 1067 rtnl_unlock(); 1068 return ret; 1069 1070 default: 1071 return -EINVAL; 1072 } 1073 } 1074 1075 #ifdef CONFIG_COMPAT 1076 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, 1077 unsigned long arg) 1078 { 1079 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1080 } 1081 #endif 1082 1083 static const struct file_operations macvtap_fops = { 1084 .owner = THIS_MODULE, 1085 .open = macvtap_open, 1086 .release = macvtap_release, 1087 .aio_read = macvtap_aio_read, 1088 .aio_write = macvtap_aio_write, 1089 .poll = macvtap_poll, 1090 .llseek = no_llseek, 1091 .unlocked_ioctl = macvtap_ioctl, 1092 #ifdef CONFIG_COMPAT 1093 .compat_ioctl = macvtap_compat_ioctl, 1094 #endif 1095 }; 1096 1097 static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, 1098 struct msghdr *m, size_t total_len) 1099 { 1100 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1101 return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen, 1102 m->msg_flags & MSG_DONTWAIT); 1103 } 1104 1105 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, 1106 struct msghdr *m, size_t total_len, 1107 int flags) 1108 { 1109 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1110 int ret; 1111 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1112 return -EINVAL; 1113 ret = macvtap_do_read(q, iocb, m->msg_iov, total_len, 1114 flags & MSG_DONTWAIT); 1115 if (ret > total_len) { 1116 m->msg_flags |= MSG_TRUNC; 1117 ret = flags & MSG_TRUNC ? ret : total_len; 1118 } 1119 return ret; 1120 } 1121 1122 /* Ops structure to mimic raw sockets with tun */ 1123 static const struct proto_ops macvtap_socket_ops = { 1124 .sendmsg = macvtap_sendmsg, 1125 .recvmsg = macvtap_recvmsg, 1126 }; 1127 1128 /* Get an underlying socket object from tun file. Returns error unless file is 1129 * attached to a device. The returned object works like a packet socket, it 1130 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1131 * holding a reference to the file for as long as the socket is in use. */ 1132 struct socket *macvtap_get_socket(struct file *file) 1133 { 1134 struct macvtap_queue *q; 1135 if (file->f_op != &macvtap_fops) 1136 return ERR_PTR(-EINVAL); 1137 q = file->private_data; 1138 if (!q) 1139 return ERR_PTR(-EBADFD); 1140 return &q->sock; 1141 } 1142 EXPORT_SYMBOL_GPL(macvtap_get_socket); 1143 1144 static int macvtap_device_event(struct notifier_block *unused, 1145 unsigned long event, void *ptr) 1146 { 1147 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1148 struct macvlan_dev *vlan; 1149 struct device *classdev; 1150 dev_t devt; 1151 int err; 1152 1153 if (dev->rtnl_link_ops != &macvtap_link_ops) 1154 return NOTIFY_DONE; 1155 1156 vlan = netdev_priv(dev); 1157 1158 switch (event) { 1159 case NETDEV_REGISTER: 1160 /* Create the device node here after the network device has 1161 * been registered but before register_netdevice has 1162 * finished running. 1163 */ 1164 err = macvtap_get_minor(vlan); 1165 if (err) 1166 return notifier_from_errno(err); 1167 1168 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1169 classdev = device_create(macvtap_class, &dev->dev, devt, 1170 dev, "tap%d", dev->ifindex); 1171 if (IS_ERR(classdev)) { 1172 macvtap_free_minor(vlan); 1173 return notifier_from_errno(PTR_ERR(classdev)); 1174 } 1175 break; 1176 case NETDEV_UNREGISTER: 1177 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1178 device_destroy(macvtap_class, devt); 1179 macvtap_free_minor(vlan); 1180 break; 1181 } 1182 1183 return NOTIFY_DONE; 1184 } 1185 1186 static struct notifier_block macvtap_notifier_block __read_mostly = { 1187 .notifier_call = macvtap_device_event, 1188 }; 1189 1190 static int macvtap_init(void) 1191 { 1192 int err; 1193 1194 err = alloc_chrdev_region(&macvtap_major, 0, 1195 MACVTAP_NUM_DEVS, "macvtap"); 1196 if (err) 1197 goto out1; 1198 1199 cdev_init(&macvtap_cdev, &macvtap_fops); 1200 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); 1201 if (err) 1202 goto out2; 1203 1204 macvtap_class = class_create(THIS_MODULE, "macvtap"); 1205 if (IS_ERR(macvtap_class)) { 1206 err = PTR_ERR(macvtap_class); 1207 goto out3; 1208 } 1209 1210 err = register_netdevice_notifier(&macvtap_notifier_block); 1211 if (err) 1212 goto out4; 1213 1214 err = macvlan_link_register(&macvtap_link_ops); 1215 if (err) 1216 goto out5; 1217 1218 return 0; 1219 1220 out5: 1221 unregister_netdevice_notifier(&macvtap_notifier_block); 1222 out4: 1223 class_unregister(macvtap_class); 1224 out3: 1225 cdev_del(&macvtap_cdev); 1226 out2: 1227 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1228 out1: 1229 return err; 1230 } 1231 module_init(macvtap_init); 1232 1233 static void macvtap_exit(void) 1234 { 1235 rtnl_link_unregister(&macvtap_link_ops); 1236 unregister_netdevice_notifier(&macvtap_notifier_block); 1237 class_unregister(macvtap_class); 1238 cdev_del(&macvtap_cdev); 1239 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1240 } 1241 module_exit(macvtap_exit); 1242 1243 MODULE_ALIAS_RTNL_LINK("macvtap"); 1244 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 1245 MODULE_LICENSE("GPL"); 1246