1 #include <linux/etherdevice.h> 2 #include <linux/if_macvlan.h> 3 #include <linux/if_vlan.h> 4 #include <linux/interrupt.h> 5 #include <linux/nsproxy.h> 6 #include <linux/compat.h> 7 #include <linux/if_tun.h> 8 #include <linux/module.h> 9 #include <linux/skbuff.h> 10 #include <linux/cache.h> 11 #include <linux/sched.h> 12 #include <linux/types.h> 13 #include <linux/slab.h> 14 #include <linux/wait.h> 15 #include <linux/cdev.h> 16 #include <linux/idr.h> 17 #include <linux/fs.h> 18 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 */ 34 struct macvtap_queue { 35 struct sock sk; 36 struct socket sock; 37 struct socket_wq wq; 38 int vnet_hdr_sz; 39 struct macvlan_dev __rcu *vlan; 40 struct file *file; 41 unsigned int flags; 42 u16 queue_index; 43 bool enabled; 44 struct list_head next; 45 }; 46 47 static struct proto macvtap_proto = { 48 .name = "macvtap", 49 .owner = THIS_MODULE, 50 .obj_size = sizeof (struct macvtap_queue), 51 }; 52 53 /* 54 * Variables for dealing with macvtaps device numbers. 55 */ 56 static dev_t macvtap_major; 57 #define MACVTAP_NUM_DEVS (1U << MINORBITS) 58 static DEFINE_MUTEX(minor_lock); 59 static DEFINE_IDR(minor_idr); 60 61 #define GOODCOPY_LEN 128 62 static struct class *macvtap_class; 63 static struct cdev macvtap_cdev; 64 65 static const struct proto_ops macvtap_socket_ops; 66 67 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ 68 NETIF_F_TSO6 | NETIF_F_UFO) 69 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) 70 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) 71 72 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev) 73 { 74 return rcu_dereference(dev->rx_handler_data); 75 } 76 77 /* 78 * RCU usage: 79 * The macvtap_queue and the macvlan_dev are loosely coupled, the 80 * pointers from one to the other can only be read while rcu_read_lock 81 * or rtnl is held. 82 * 83 * Both the file and the macvlan_dev hold a reference on the macvtap_queue 84 * through sock_hold(&q->sk). When the macvlan_dev goes away first, 85 * q->vlan becomes inaccessible. When the files gets closed, 86 * macvtap_get_queue() fails. 87 * 88 * There may still be references to the struct sock inside of the 89 * queue from outbound SKBs, but these never reference back to the 90 * file or the dev. The data structure is freed through __sk_free 91 * when both our references and any pending SKBs are gone. 92 */ 93 94 static int macvtap_enable_queue(struct net_device *dev, struct file *file, 95 struct macvtap_queue *q) 96 { 97 struct macvlan_dev *vlan = netdev_priv(dev); 98 int err = -EINVAL; 99 100 ASSERT_RTNL(); 101 102 if (q->enabled) 103 goto out; 104 105 err = 0; 106 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 107 q->queue_index = vlan->numvtaps; 108 q->enabled = true; 109 110 vlan->numvtaps++; 111 out: 112 return err; 113 } 114 115 static int macvtap_set_queue(struct net_device *dev, struct file *file, 116 struct macvtap_queue *q) 117 { 118 struct macvlan_dev *vlan = netdev_priv(dev); 119 int err = -EBUSY; 120 121 rtnl_lock(); 122 if (vlan->numqueues == MAX_MACVTAP_QUEUES) 123 goto out; 124 125 err = 0; 126 rcu_assign_pointer(q->vlan, vlan); 127 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 128 sock_hold(&q->sk); 129 130 q->file = file; 131 q->queue_index = vlan->numvtaps; 132 q->enabled = true; 133 file->private_data = q; 134 list_add_tail(&q->next, &vlan->queue_list); 135 136 vlan->numvtaps++; 137 vlan->numqueues++; 138 139 out: 140 rtnl_unlock(); 141 return err; 142 } 143 144 static int macvtap_disable_queue(struct macvtap_queue *q) 145 { 146 struct macvlan_dev *vlan; 147 struct macvtap_queue *nq; 148 149 ASSERT_RTNL(); 150 if (!q->enabled) 151 return -EINVAL; 152 153 vlan = rtnl_dereference(q->vlan); 154 155 if (vlan) { 156 int index = q->queue_index; 157 BUG_ON(index >= vlan->numvtaps); 158 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]); 159 nq->queue_index = index; 160 161 rcu_assign_pointer(vlan->taps[index], nq); 162 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); 163 q->enabled = false; 164 165 vlan->numvtaps--; 166 } 167 168 return 0; 169 } 170 171 /* 172 * The file owning the queue got closed, give up both 173 * the reference that the files holds as well as the 174 * one from the macvlan_dev if that still exists. 175 * 176 * Using the spinlock makes sure that we don't get 177 * to the queue again after destroying it. 178 */ 179 static void macvtap_put_queue(struct macvtap_queue *q) 180 { 181 struct macvlan_dev *vlan; 182 183 rtnl_lock(); 184 vlan = rtnl_dereference(q->vlan); 185 186 if (vlan) { 187 if (q->enabled) 188 BUG_ON(macvtap_disable_queue(q)); 189 190 vlan->numqueues--; 191 RCU_INIT_POINTER(q->vlan, NULL); 192 sock_put(&q->sk); 193 list_del_init(&q->next); 194 } 195 196 rtnl_unlock(); 197 198 synchronize_rcu(); 199 sock_put(&q->sk); 200 } 201 202 /* 203 * Select a queue based on the rxq of the device on which this packet 204 * arrived. If the incoming device is not mq, calculate a flow hash 205 * to select a queue. If all fails, find the first available queue. 206 * Cache vlan->numvtaps since it can become zero during the execution 207 * of this function. 208 */ 209 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, 210 struct sk_buff *skb) 211 { 212 struct macvlan_dev *vlan = netdev_priv(dev); 213 struct macvtap_queue *tap = NULL; 214 /* Access to taps array is protected by rcu, but access to numvtaps 215 * isn't. Below we use it to lookup a queue, but treat it as a hint 216 * and validate that the result isn't NULL - in case we are 217 * racing against queue removal. 218 */ 219 int numvtaps = ACCESS_ONCE(vlan->numvtaps); 220 __u32 rxq; 221 222 if (!numvtaps) 223 goto out; 224 225 /* Check if we can use flow to select a queue */ 226 rxq = skb_get_hash(skb); 227 if (rxq) { 228 tap = rcu_dereference(vlan->taps[rxq % numvtaps]); 229 goto out; 230 } 231 232 if (likely(skb_rx_queue_recorded(skb))) { 233 rxq = skb_get_rx_queue(skb); 234 235 while (unlikely(rxq >= numvtaps)) 236 rxq -= numvtaps; 237 238 tap = rcu_dereference(vlan->taps[rxq]); 239 goto out; 240 } 241 242 tap = rcu_dereference(vlan->taps[0]); 243 out: 244 return tap; 245 } 246 247 /* 248 * The net_device is going away, give up the reference 249 * that it holds on all queues and safely set the pointer 250 * from the queues to NULL. 251 */ 252 static void macvtap_del_queues(struct net_device *dev) 253 { 254 struct macvlan_dev *vlan = netdev_priv(dev); 255 struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES]; 256 int i, j = 0; 257 258 ASSERT_RTNL(); 259 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { 260 list_del_init(&q->next); 261 qlist[j++] = q; 262 RCU_INIT_POINTER(q->vlan, NULL); 263 if (q->enabled) 264 vlan->numvtaps--; 265 vlan->numqueues--; 266 } 267 for (i = 0; i < vlan->numvtaps; i++) 268 RCU_INIT_POINTER(vlan->taps[i], NULL); 269 BUG_ON(vlan->numvtaps); 270 BUG_ON(vlan->numqueues); 271 /* guarantee that any future macvtap_set_queue will fail */ 272 vlan->numvtaps = MAX_MACVTAP_QUEUES; 273 274 for (--j; j >= 0; j--) 275 sock_put(&qlist[j]->sk); 276 } 277 278 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb) 279 { 280 struct sk_buff *skb = *pskb; 281 struct net_device *dev = skb->dev; 282 struct macvlan_dev *vlan; 283 struct macvtap_queue *q; 284 netdev_features_t features = TAP_FEATURES; 285 286 vlan = macvtap_get_vlan_rcu(dev); 287 if (!vlan) 288 return RX_HANDLER_PASS; 289 290 q = macvtap_get_queue(dev, skb); 291 if (!q) 292 return RX_HANDLER_PASS; 293 294 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) 295 goto drop; 296 297 skb_push(skb, ETH_HLEN); 298 299 /* Apply the forward feature mask so that we perform segmentation 300 * according to users wishes. This only works if VNET_HDR is 301 * enabled. 302 */ 303 if (q->flags & IFF_VNET_HDR) 304 features |= vlan->tap_features; 305 if (netif_needs_gso(skb, features)) { 306 struct sk_buff *segs = __skb_gso_segment(skb, features, false); 307 308 if (IS_ERR(segs)) 309 goto drop; 310 311 if (!segs) { 312 skb_queue_tail(&q->sk.sk_receive_queue, skb); 313 goto wake_up; 314 } 315 316 kfree_skb(skb); 317 while (segs) { 318 struct sk_buff *nskb = segs->next; 319 320 segs->next = NULL; 321 skb_queue_tail(&q->sk.sk_receive_queue, segs); 322 segs = nskb; 323 } 324 } else { 325 skb_queue_tail(&q->sk.sk_receive_queue, skb); 326 } 327 328 wake_up: 329 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); 330 return RX_HANDLER_CONSUMED; 331 332 drop: 333 /* Count errors/drops only here, thus don't care about args. */ 334 macvlan_count_rx(vlan, 0, 0, 0); 335 kfree_skb(skb); 336 return RX_HANDLER_CONSUMED; 337 } 338 339 static int macvtap_get_minor(struct macvlan_dev *vlan) 340 { 341 int retval = -ENOMEM; 342 343 mutex_lock(&minor_lock); 344 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); 345 if (retval >= 0) { 346 vlan->minor = retval; 347 } else if (retval == -ENOSPC) { 348 printk(KERN_ERR "too many macvtap devices\n"); 349 retval = -EINVAL; 350 } 351 mutex_unlock(&minor_lock); 352 return retval < 0 ? retval : 0; 353 } 354 355 static void macvtap_free_minor(struct macvlan_dev *vlan) 356 { 357 mutex_lock(&minor_lock); 358 if (vlan->minor) { 359 idr_remove(&minor_idr, vlan->minor); 360 vlan->minor = 0; 361 } 362 mutex_unlock(&minor_lock); 363 } 364 365 static struct net_device *dev_get_by_macvtap_minor(int minor) 366 { 367 struct net_device *dev = NULL; 368 struct macvlan_dev *vlan; 369 370 mutex_lock(&minor_lock); 371 vlan = idr_find(&minor_idr, minor); 372 if (vlan) { 373 dev = vlan->dev; 374 dev_hold(dev); 375 } 376 mutex_unlock(&minor_lock); 377 return dev; 378 } 379 380 static int macvtap_newlink(struct net *src_net, 381 struct net_device *dev, 382 struct nlattr *tb[], 383 struct nlattr *data[]) 384 { 385 struct macvlan_dev *vlan = netdev_priv(dev); 386 int err; 387 388 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 err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan); 396 if (err) 397 return err; 398 399 /* Don't put anything that may fail after macvlan_common_newlink 400 * because we can't undo what it does. 401 */ 402 return macvlan_common_newlink(src_net, dev, tb, data); 403 } 404 405 static void macvtap_dellink(struct net_device *dev, 406 struct list_head *head) 407 { 408 netdev_rx_handler_unregister(dev); 409 macvtap_del_queues(dev); 410 macvlan_dellink(dev, head); 411 } 412 413 static void macvtap_setup(struct net_device *dev) 414 { 415 macvlan_common_setup(dev); 416 dev->tx_queue_len = TUN_READQ_SIZE; 417 } 418 419 static struct rtnl_link_ops macvtap_link_ops __read_mostly = { 420 .kind = "macvtap", 421 .setup = macvtap_setup, 422 .newlink = macvtap_newlink, 423 .dellink = macvtap_dellink, 424 }; 425 426 427 static void macvtap_sock_write_space(struct sock *sk) 428 { 429 wait_queue_head_t *wqueue; 430 431 if (!sock_writeable(sk) || 432 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 433 return; 434 435 wqueue = sk_sleep(sk); 436 if (wqueue && waitqueue_active(wqueue)) 437 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); 438 } 439 440 static void macvtap_sock_destruct(struct sock *sk) 441 { 442 skb_queue_purge(&sk->sk_receive_queue); 443 } 444 445 static int macvtap_open(struct inode *inode, struct file *file) 446 { 447 struct net *net = current->nsproxy->net_ns; 448 struct net_device *dev = dev_get_by_macvtap_minor(iminor(inode)); 449 struct macvtap_queue *q; 450 int err; 451 452 err = -ENODEV; 453 if (!dev) 454 goto out; 455 456 err = -ENOMEM; 457 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 458 &macvtap_proto); 459 if (!q) 460 goto out; 461 462 RCU_INIT_POINTER(q->sock.wq, &q->wq); 463 init_waitqueue_head(&q->wq.wait); 464 q->sock.type = SOCK_RAW; 465 q->sock.state = SS_CONNECTED; 466 q->sock.file = file; 467 q->sock.ops = &macvtap_socket_ops; 468 sock_init_data(&q->sock, &q->sk); 469 q->sk.sk_write_space = macvtap_sock_write_space; 470 q->sk.sk_destruct = macvtap_sock_destruct; 471 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; 472 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 473 474 /* 475 * so far only KVM virtio_net uses macvtap, enable zero copy between 476 * guest kernel and host kernel when lower device supports zerocopy 477 * 478 * The macvlan supports zerocopy iff the lower device supports zero 479 * copy so we don't have to look at the lower device directly. 480 */ 481 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) 482 sock_set_flag(&q->sk, SOCK_ZEROCOPY); 483 484 err = macvtap_set_queue(dev, file, q); 485 if (err) 486 sock_put(&q->sk); 487 488 out: 489 if (dev) 490 dev_put(dev); 491 492 return err; 493 } 494 495 static int macvtap_release(struct inode *inode, struct file *file) 496 { 497 struct macvtap_queue *q = file->private_data; 498 macvtap_put_queue(q); 499 return 0; 500 } 501 502 static unsigned int macvtap_poll(struct file *file, poll_table * wait) 503 { 504 struct macvtap_queue *q = file->private_data; 505 unsigned int mask = POLLERR; 506 507 if (!q) 508 goto out; 509 510 mask = 0; 511 poll_wait(file, &q->wq.wait, wait); 512 513 if (!skb_queue_empty(&q->sk.sk_receive_queue)) 514 mask |= POLLIN | POLLRDNORM; 515 516 if (sock_writeable(&q->sk) || 517 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && 518 sock_writeable(&q->sk))) 519 mask |= POLLOUT | POLLWRNORM; 520 521 out: 522 return mask; 523 } 524 525 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, 526 size_t len, size_t linear, 527 int noblock, int *err) 528 { 529 struct sk_buff *skb; 530 531 /* Under a page? Don't bother with paged skb. */ 532 if (prepad + len < PAGE_SIZE || !linear) 533 linear = len; 534 535 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 536 err, 0); 537 if (!skb) 538 return NULL; 539 540 skb_reserve(skb, prepad); 541 skb_put(skb, linear); 542 skb->data_len = len - linear; 543 skb->len += len - linear; 544 545 return skb; 546 } 547 548 /* 549 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should 550 * be shared with the tun/tap driver. 551 */ 552 static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb, 553 struct virtio_net_hdr *vnet_hdr) 554 { 555 unsigned short gso_type = 0; 556 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 557 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 558 case VIRTIO_NET_HDR_GSO_TCPV4: 559 gso_type = SKB_GSO_TCPV4; 560 break; 561 case VIRTIO_NET_HDR_GSO_TCPV6: 562 gso_type = SKB_GSO_TCPV6; 563 break; 564 case VIRTIO_NET_HDR_GSO_UDP: 565 gso_type = SKB_GSO_UDP; 566 break; 567 default: 568 return -EINVAL; 569 } 570 571 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) 572 gso_type |= SKB_GSO_TCP_ECN; 573 574 if (vnet_hdr->gso_size == 0) 575 return -EINVAL; 576 } 577 578 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 579 if (!skb_partial_csum_set(skb, vnet_hdr->csum_start, 580 vnet_hdr->csum_offset)) 581 return -EINVAL; 582 } 583 584 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 585 skb_shinfo(skb)->gso_size = vnet_hdr->gso_size; 586 skb_shinfo(skb)->gso_type = gso_type; 587 588 /* Header must be checked, and gso_segs computed. */ 589 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 590 skb_shinfo(skb)->gso_segs = 0; 591 } 592 return 0; 593 } 594 595 static void macvtap_skb_to_vnet_hdr(const struct sk_buff *skb, 596 struct virtio_net_hdr *vnet_hdr) 597 { 598 memset(vnet_hdr, 0, sizeof(*vnet_hdr)); 599 600 if (skb_is_gso(skb)) { 601 struct skb_shared_info *sinfo = skb_shinfo(skb); 602 603 /* This is a hint as to how much should be linear. */ 604 vnet_hdr->hdr_len = skb_headlen(skb); 605 vnet_hdr->gso_size = sinfo->gso_size; 606 if (sinfo->gso_type & SKB_GSO_TCPV4) 607 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 608 else if (sinfo->gso_type & SKB_GSO_TCPV6) 609 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 610 else if (sinfo->gso_type & SKB_GSO_UDP) 611 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; 612 else 613 BUG(); 614 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 615 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 616 } else 617 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 618 619 if (skb->ip_summed == CHECKSUM_PARTIAL) { 620 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 621 vnet_hdr->csum_start = skb_checksum_start_offset(skb); 622 vnet_hdr->csum_offset = skb->csum_offset; 623 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 624 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; 625 } /* else everything is zero */ 626 } 627 628 /* Get packet from user space buffer */ 629 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 630 const struct iovec *iv, unsigned long total_len, 631 size_t count, int noblock) 632 { 633 int good_linear = SKB_MAX_HEAD(NET_IP_ALIGN); 634 struct sk_buff *skb; 635 struct macvlan_dev *vlan; 636 unsigned long len = total_len; 637 int err; 638 struct virtio_net_hdr vnet_hdr = { 0 }; 639 int vnet_hdr_len = 0; 640 int copylen = 0; 641 bool zerocopy = false; 642 size_t linear; 643 644 if (q->flags & IFF_VNET_HDR) { 645 vnet_hdr_len = q->vnet_hdr_sz; 646 647 err = -EINVAL; 648 if (len < vnet_hdr_len) 649 goto err; 650 len -= vnet_hdr_len; 651 652 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0, 653 sizeof(vnet_hdr)); 654 if (err < 0) 655 goto err; 656 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 657 vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 > 658 vnet_hdr.hdr_len) 659 vnet_hdr.hdr_len = vnet_hdr.csum_start + 660 vnet_hdr.csum_offset + 2; 661 err = -EINVAL; 662 if (vnet_hdr.hdr_len > len) 663 goto err; 664 } 665 666 err = -EINVAL; 667 if (unlikely(len < ETH_HLEN)) 668 goto err; 669 670 err = -EMSGSIZE; 671 if (unlikely(count > UIO_MAXIOV)) 672 goto err; 673 674 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { 675 copylen = vnet_hdr.hdr_len ? vnet_hdr.hdr_len : GOODCOPY_LEN; 676 if (copylen > good_linear) 677 copylen = good_linear; 678 linear = copylen; 679 if (iov_pages(iv, vnet_hdr_len + copylen, count) 680 <= MAX_SKB_FRAGS) 681 zerocopy = true; 682 } 683 684 if (!zerocopy) { 685 copylen = len; 686 if (vnet_hdr.hdr_len > good_linear) 687 linear = good_linear; 688 else 689 linear = vnet_hdr.hdr_len; 690 } 691 692 skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, 693 linear, 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 else { 700 err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, 701 len); 702 if (!err && m && m->msg_control) { 703 struct ubuf_info *uarg = m->msg_control; 704 uarg->callback(uarg, false); 705 } 706 } 707 708 if (err) 709 goto err_kfree; 710 711 skb_set_network_header(skb, ETH_HLEN); 712 skb_reset_mac_header(skb); 713 skb->protocol = eth_hdr(skb)->h_proto; 714 715 if (vnet_hdr_len) { 716 err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr); 717 if (err) 718 goto err_kfree; 719 } 720 721 skb_probe_transport_header(skb, ETH_HLEN); 722 723 rcu_read_lock(); 724 vlan = rcu_dereference(q->vlan); 725 /* copy skb_ubuf_info for callback when skb has no error */ 726 if (zerocopy) { 727 skb_shinfo(skb)->destructor_arg = m->msg_control; 728 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 729 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 730 } 731 if (vlan) { 732 skb->dev = vlan->dev; 733 dev_queue_xmit(skb); 734 } else { 735 kfree_skb(skb); 736 } 737 rcu_read_unlock(); 738 739 return total_len; 740 741 err_kfree: 742 kfree_skb(skb); 743 744 err: 745 rcu_read_lock(); 746 vlan = rcu_dereference(q->vlan); 747 if (vlan) 748 this_cpu_inc(vlan->pcpu_stats->tx_dropped); 749 rcu_read_unlock(); 750 751 return err; 752 } 753 754 static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv, 755 unsigned long count, loff_t pos) 756 { 757 struct file *file = iocb->ki_filp; 758 ssize_t result = -ENOLINK; 759 struct macvtap_queue *q = file->private_data; 760 761 result = macvtap_get_user(q, NULL, iv, iov_length(iv, count), count, 762 file->f_flags & O_NONBLOCK); 763 return result; 764 } 765 766 /* Put packet to the user space buffer */ 767 static ssize_t macvtap_put_user(struct macvtap_queue *q, 768 const struct sk_buff *skb, 769 const struct iovec *iv, int len) 770 { 771 int ret; 772 int vnet_hdr_len = 0; 773 int vlan_offset = 0; 774 int copied, total; 775 776 if (q->flags & IFF_VNET_HDR) { 777 struct virtio_net_hdr vnet_hdr; 778 vnet_hdr_len = q->vnet_hdr_sz; 779 if ((len -= vnet_hdr_len) < 0) 780 return -EINVAL; 781 782 macvtap_skb_to_vnet_hdr(skb, &vnet_hdr); 783 784 if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, sizeof(vnet_hdr))) 785 return -EFAULT; 786 } 787 total = copied = vnet_hdr_len; 788 total += skb->len; 789 790 if (!vlan_tx_tag_present(skb)) 791 len = min_t(int, skb->len, len); 792 else { 793 int copy; 794 struct { 795 __be16 h_vlan_proto; 796 __be16 h_vlan_TCI; 797 } veth; 798 veth.h_vlan_proto = skb->vlan_proto; 799 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 800 801 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 802 len = min_t(int, skb->len + VLAN_HLEN, len); 803 total += VLAN_HLEN; 804 805 copy = min_t(int, vlan_offset, len); 806 ret = skb_copy_datagram_const_iovec(skb, 0, iv, copied, copy); 807 len -= copy; 808 copied += copy; 809 if (ret || !len) 810 goto done; 811 812 copy = min_t(int, sizeof(veth), len); 813 ret = memcpy_toiovecend(iv, (void *)&veth, copied, copy); 814 len -= copy; 815 copied += copy; 816 if (ret || !len) 817 goto done; 818 } 819 820 ret = skb_copy_datagram_const_iovec(skb, vlan_offset, iv, copied, len); 821 822 done: 823 return ret ? ret : total; 824 } 825 826 static ssize_t macvtap_do_read(struct macvtap_queue *q, 827 const struct iovec *iv, unsigned long len, 828 int noblock) 829 { 830 DEFINE_WAIT(wait); 831 struct sk_buff *skb; 832 ssize_t ret = 0; 833 834 while (len) { 835 if (!noblock) 836 prepare_to_wait(sk_sleep(&q->sk), &wait, 837 TASK_INTERRUPTIBLE); 838 839 /* Read frames from the queue */ 840 skb = skb_dequeue(&q->sk.sk_receive_queue); 841 if (!skb) { 842 if (noblock) { 843 ret = -EAGAIN; 844 break; 845 } 846 if (signal_pending(current)) { 847 ret = -ERESTARTSYS; 848 break; 849 } 850 /* Nothing to read, let's sleep */ 851 schedule(); 852 continue; 853 } 854 ret = macvtap_put_user(q, skb, iv, len); 855 kfree_skb(skb); 856 break; 857 } 858 859 if (!noblock) 860 finish_wait(sk_sleep(&q->sk), &wait); 861 return ret; 862 } 863 864 static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv, 865 unsigned long count, loff_t pos) 866 { 867 struct file *file = iocb->ki_filp; 868 struct macvtap_queue *q = file->private_data; 869 ssize_t len, ret = 0; 870 871 len = iov_length(iv, count); 872 if (len < 0) { 873 ret = -EINVAL; 874 goto out; 875 } 876 877 ret = macvtap_do_read(q, iv, len, file->f_flags & O_NONBLOCK); 878 ret = min_t(ssize_t, ret, len); 879 if (ret > 0) 880 iocb->ki_pos = ret; 881 out: 882 return ret; 883 } 884 885 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) 886 { 887 struct macvlan_dev *vlan; 888 889 ASSERT_RTNL(); 890 vlan = rtnl_dereference(q->vlan); 891 if (vlan) 892 dev_hold(vlan->dev); 893 894 return vlan; 895 } 896 897 static void macvtap_put_vlan(struct macvlan_dev *vlan) 898 { 899 dev_put(vlan->dev); 900 } 901 902 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) 903 { 904 struct macvtap_queue *q = file->private_data; 905 struct macvlan_dev *vlan; 906 int ret; 907 908 vlan = macvtap_get_vlan(q); 909 if (!vlan) 910 return -EINVAL; 911 912 if (flags & IFF_ATTACH_QUEUE) 913 ret = macvtap_enable_queue(vlan->dev, file, q); 914 else if (flags & IFF_DETACH_QUEUE) 915 ret = macvtap_disable_queue(q); 916 else 917 ret = -EINVAL; 918 919 macvtap_put_vlan(vlan); 920 return ret; 921 } 922 923 static int set_offload(struct macvtap_queue *q, unsigned long arg) 924 { 925 struct macvlan_dev *vlan; 926 netdev_features_t features; 927 netdev_features_t feature_mask = 0; 928 929 vlan = rtnl_dereference(q->vlan); 930 if (!vlan) 931 return -ENOLINK; 932 933 features = vlan->dev->features; 934 935 if (arg & TUN_F_CSUM) { 936 feature_mask = NETIF_F_HW_CSUM; 937 938 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { 939 if (arg & TUN_F_TSO_ECN) 940 feature_mask |= NETIF_F_TSO_ECN; 941 if (arg & TUN_F_TSO4) 942 feature_mask |= NETIF_F_TSO; 943 if (arg & TUN_F_TSO6) 944 feature_mask |= NETIF_F_TSO6; 945 } 946 947 if (arg & TUN_F_UFO) 948 feature_mask |= NETIF_F_UFO; 949 } 950 951 /* tun/tap driver inverts the usage for TSO offloads, where 952 * setting the TSO bit means that the userspace wants to 953 * accept TSO frames and turning it off means that user space 954 * does not support TSO. 955 * For macvtap, we have to invert it to mean the same thing. 956 * When user space turns off TSO, we turn off GSO/LRO so that 957 * user-space will not receive TSO frames. 958 */ 959 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) 960 features |= RX_OFFLOADS; 961 else 962 features &= ~RX_OFFLOADS; 963 964 /* tap_features are the same as features on tun/tap and 965 * reflect user expectations. 966 */ 967 vlan->tap_features = feature_mask; 968 vlan->set_features = features; 969 netdev_update_features(vlan->dev); 970 971 return 0; 972 } 973 974 /* 975 * provide compatibility with generic tun/tap interface 976 */ 977 static long macvtap_ioctl(struct file *file, unsigned int cmd, 978 unsigned long arg) 979 { 980 struct macvtap_queue *q = file->private_data; 981 struct macvlan_dev *vlan; 982 void __user *argp = (void __user *)arg; 983 struct ifreq __user *ifr = argp; 984 unsigned int __user *up = argp; 985 unsigned int u; 986 int __user *sp = argp; 987 int s; 988 int ret; 989 990 switch (cmd) { 991 case TUNSETIFF: 992 /* ignore the name, just look at flags */ 993 if (get_user(u, &ifr->ifr_flags)) 994 return -EFAULT; 995 996 ret = 0; 997 if ((u & ~(IFF_VNET_HDR | IFF_MULTI_QUEUE)) != 998 (IFF_NO_PI | IFF_TAP)) 999 ret = -EINVAL; 1000 else 1001 q->flags = u; 1002 1003 return ret; 1004 1005 case TUNGETIFF: 1006 rtnl_lock(); 1007 vlan = macvtap_get_vlan(q); 1008 if (!vlan) { 1009 rtnl_unlock(); 1010 return -ENOLINK; 1011 } 1012 1013 ret = 0; 1014 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1015 put_user(q->flags, &ifr->ifr_flags)) 1016 ret = -EFAULT; 1017 macvtap_put_vlan(vlan); 1018 rtnl_unlock(); 1019 return ret; 1020 1021 case TUNSETQUEUE: 1022 if (get_user(u, &ifr->ifr_flags)) 1023 return -EFAULT; 1024 rtnl_lock(); 1025 ret = macvtap_ioctl_set_queue(file, u); 1026 rtnl_unlock(); 1027 return ret; 1028 1029 case TUNGETFEATURES: 1030 if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR | 1031 IFF_MULTI_QUEUE, up)) 1032 return -EFAULT; 1033 return 0; 1034 1035 case TUNSETSNDBUF: 1036 if (get_user(u, up)) 1037 return -EFAULT; 1038 1039 q->sk.sk_sndbuf = u; 1040 return 0; 1041 1042 case TUNGETVNETHDRSZ: 1043 s = q->vnet_hdr_sz; 1044 if (put_user(s, sp)) 1045 return -EFAULT; 1046 return 0; 1047 1048 case TUNSETVNETHDRSZ: 1049 if (get_user(s, sp)) 1050 return -EFAULT; 1051 if (s < (int)sizeof(struct virtio_net_hdr)) 1052 return -EINVAL; 1053 1054 q->vnet_hdr_sz = s; 1055 return 0; 1056 1057 case TUNSETOFFLOAD: 1058 /* let the user check for future flags */ 1059 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 1060 TUN_F_TSO_ECN | TUN_F_UFO)) 1061 return -EINVAL; 1062 1063 rtnl_lock(); 1064 ret = set_offload(q, arg); 1065 rtnl_unlock(); 1066 return ret; 1067 1068 default: 1069 return -EINVAL; 1070 } 1071 } 1072 1073 #ifdef CONFIG_COMPAT 1074 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, 1075 unsigned long arg) 1076 { 1077 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1078 } 1079 #endif 1080 1081 static const struct file_operations macvtap_fops = { 1082 .owner = THIS_MODULE, 1083 .open = macvtap_open, 1084 .release = macvtap_release, 1085 .aio_read = macvtap_aio_read, 1086 .aio_write = macvtap_aio_write, 1087 .poll = macvtap_poll, 1088 .llseek = no_llseek, 1089 .unlocked_ioctl = macvtap_ioctl, 1090 #ifdef CONFIG_COMPAT 1091 .compat_ioctl = macvtap_compat_ioctl, 1092 #endif 1093 }; 1094 1095 static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, 1096 struct msghdr *m, size_t total_len) 1097 { 1098 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1099 return macvtap_get_user(q, m, m->msg_iov, total_len, m->msg_iovlen, 1100 m->msg_flags & MSG_DONTWAIT); 1101 } 1102 1103 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, 1104 struct msghdr *m, size_t total_len, 1105 int flags) 1106 { 1107 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1108 int ret; 1109 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1110 return -EINVAL; 1111 ret = macvtap_do_read(q, m->msg_iov, total_len, 1112 flags & MSG_DONTWAIT); 1113 if (ret > total_len) { 1114 m->msg_flags |= MSG_TRUNC; 1115 ret = flags & MSG_TRUNC ? ret : total_len; 1116 } 1117 return ret; 1118 } 1119 1120 /* Ops structure to mimic raw sockets with tun */ 1121 static const struct proto_ops macvtap_socket_ops = { 1122 .sendmsg = macvtap_sendmsg, 1123 .recvmsg = macvtap_recvmsg, 1124 }; 1125 1126 /* Get an underlying socket object from tun file. Returns error unless file is 1127 * attached to a device. The returned object works like a packet socket, it 1128 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1129 * holding a reference to the file for as long as the socket is in use. */ 1130 struct socket *macvtap_get_socket(struct file *file) 1131 { 1132 struct macvtap_queue *q; 1133 if (file->f_op != &macvtap_fops) 1134 return ERR_PTR(-EINVAL); 1135 q = file->private_data; 1136 if (!q) 1137 return ERR_PTR(-EBADFD); 1138 return &q->sock; 1139 } 1140 EXPORT_SYMBOL_GPL(macvtap_get_socket); 1141 1142 static int macvtap_device_event(struct notifier_block *unused, 1143 unsigned long event, void *ptr) 1144 { 1145 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1146 struct macvlan_dev *vlan; 1147 struct device *classdev; 1148 dev_t devt; 1149 int err; 1150 1151 if (dev->rtnl_link_ops != &macvtap_link_ops) 1152 return NOTIFY_DONE; 1153 1154 vlan = netdev_priv(dev); 1155 1156 switch (event) { 1157 case NETDEV_REGISTER: 1158 /* Create the device node here after the network device has 1159 * been registered but before register_netdevice has 1160 * finished running. 1161 */ 1162 err = macvtap_get_minor(vlan); 1163 if (err) 1164 return notifier_from_errno(err); 1165 1166 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1167 classdev = device_create(macvtap_class, &dev->dev, devt, 1168 dev, "tap%d", dev->ifindex); 1169 if (IS_ERR(classdev)) { 1170 macvtap_free_minor(vlan); 1171 return notifier_from_errno(PTR_ERR(classdev)); 1172 } 1173 break; 1174 case NETDEV_UNREGISTER: 1175 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1176 device_destroy(macvtap_class, devt); 1177 macvtap_free_minor(vlan); 1178 break; 1179 } 1180 1181 return NOTIFY_DONE; 1182 } 1183 1184 static struct notifier_block macvtap_notifier_block __read_mostly = { 1185 .notifier_call = macvtap_device_event, 1186 }; 1187 1188 static int macvtap_init(void) 1189 { 1190 int err; 1191 1192 err = alloc_chrdev_region(&macvtap_major, 0, 1193 MACVTAP_NUM_DEVS, "macvtap"); 1194 if (err) 1195 goto out1; 1196 1197 cdev_init(&macvtap_cdev, &macvtap_fops); 1198 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); 1199 if (err) 1200 goto out2; 1201 1202 macvtap_class = class_create(THIS_MODULE, "macvtap"); 1203 if (IS_ERR(macvtap_class)) { 1204 err = PTR_ERR(macvtap_class); 1205 goto out3; 1206 } 1207 1208 err = register_netdevice_notifier(&macvtap_notifier_block); 1209 if (err) 1210 goto out4; 1211 1212 err = macvlan_link_register(&macvtap_link_ops); 1213 if (err) 1214 goto out5; 1215 1216 return 0; 1217 1218 out5: 1219 unregister_netdevice_notifier(&macvtap_notifier_block); 1220 out4: 1221 class_unregister(macvtap_class); 1222 out3: 1223 cdev_del(&macvtap_cdev); 1224 out2: 1225 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1226 out1: 1227 return err; 1228 } 1229 module_init(macvtap_init); 1230 1231 static void macvtap_exit(void) 1232 { 1233 rtnl_link_unregister(&macvtap_link_ops); 1234 unregister_netdevice_notifier(&macvtap_notifier_block); 1235 class_unregister(macvtap_class); 1236 cdev_del(&macvtap_cdev); 1237 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1238 } 1239 module_exit(macvtap_exit); 1240 1241 MODULE_ALIAS_RTNL_LINK("macvtap"); 1242 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 1243 MODULE_LICENSE("GPL"); 1244