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 #include <linux/uio.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 #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) 49 50 #define MACVTAP_VNET_LE 0x80000000 51 #define MACVTAP_VNET_BE 0x40000000 52 53 #ifdef CONFIG_TUN_VNET_CROSS_LE 54 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) 55 { 56 return q->flags & MACVTAP_VNET_BE ? false : 57 virtio_legacy_is_little_endian(); 58 } 59 60 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *sp) 61 { 62 int s = !!(q->flags & MACVTAP_VNET_BE); 63 64 if (put_user(s, sp)) 65 return -EFAULT; 66 67 return 0; 68 } 69 70 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *sp) 71 { 72 int s; 73 74 if (get_user(s, sp)) 75 return -EFAULT; 76 77 if (s) 78 q->flags |= MACVTAP_VNET_BE; 79 else 80 q->flags &= ~MACVTAP_VNET_BE; 81 82 return 0; 83 } 84 #else 85 static inline bool macvtap_legacy_is_little_endian(struct macvtap_queue *q) 86 { 87 return virtio_legacy_is_little_endian(); 88 } 89 90 static long macvtap_get_vnet_be(struct macvtap_queue *q, int __user *argp) 91 { 92 return -EINVAL; 93 } 94 95 static long macvtap_set_vnet_be(struct macvtap_queue *q, int __user *argp) 96 { 97 return -EINVAL; 98 } 99 #endif /* CONFIG_TUN_VNET_CROSS_LE */ 100 101 static inline bool macvtap_is_little_endian(struct macvtap_queue *q) 102 { 103 return q->flags & MACVTAP_VNET_LE || 104 macvtap_legacy_is_little_endian(q); 105 } 106 107 static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) 108 { 109 return __virtio16_to_cpu(macvtap_is_little_endian(q), val); 110 } 111 112 static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val) 113 { 114 return __cpu_to_virtio16(macvtap_is_little_endian(q), val); 115 } 116 117 static struct proto macvtap_proto = { 118 .name = "macvtap", 119 .owner = THIS_MODULE, 120 .obj_size = sizeof (struct macvtap_queue), 121 }; 122 123 /* 124 * Variables for dealing with macvtaps device numbers. 125 */ 126 static dev_t macvtap_major; 127 #define MACVTAP_NUM_DEVS (1U << MINORBITS) 128 static DEFINE_MUTEX(minor_lock); 129 static DEFINE_IDR(minor_idr); 130 131 #define GOODCOPY_LEN 128 132 static struct class *macvtap_class; 133 static struct cdev macvtap_cdev; 134 135 static const struct proto_ops macvtap_socket_ops; 136 137 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ 138 NETIF_F_TSO6 | NETIF_F_UFO) 139 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) 140 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) 141 142 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev) 143 { 144 return rcu_dereference(dev->rx_handler_data); 145 } 146 147 /* 148 * RCU usage: 149 * The macvtap_queue and the macvlan_dev are loosely coupled, the 150 * pointers from one to the other can only be read while rcu_read_lock 151 * or rtnl is held. 152 * 153 * Both the file and the macvlan_dev hold a reference on the macvtap_queue 154 * through sock_hold(&q->sk). When the macvlan_dev goes away first, 155 * q->vlan becomes inaccessible. When the files gets closed, 156 * macvtap_get_queue() fails. 157 * 158 * There may still be references to the struct sock inside of the 159 * queue from outbound SKBs, but these never reference back to the 160 * file or the dev. The data structure is freed through __sk_free 161 * when both our references and any pending SKBs are gone. 162 */ 163 164 static int macvtap_enable_queue(struct net_device *dev, struct file *file, 165 struct macvtap_queue *q) 166 { 167 struct macvlan_dev *vlan = netdev_priv(dev); 168 int err = -EINVAL; 169 170 ASSERT_RTNL(); 171 172 if (q->enabled) 173 goto out; 174 175 err = 0; 176 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 177 q->queue_index = vlan->numvtaps; 178 q->enabled = true; 179 180 vlan->numvtaps++; 181 out: 182 return err; 183 } 184 185 /* Requires RTNL */ 186 static int macvtap_set_queue(struct net_device *dev, struct file *file, 187 struct macvtap_queue *q) 188 { 189 struct macvlan_dev *vlan = netdev_priv(dev); 190 191 if (vlan->numqueues == MAX_MACVTAP_QUEUES) 192 return -EBUSY; 193 194 rcu_assign_pointer(q->vlan, vlan); 195 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 196 sock_hold(&q->sk); 197 198 q->file = file; 199 q->queue_index = vlan->numvtaps; 200 q->enabled = true; 201 file->private_data = q; 202 list_add_tail(&q->next, &vlan->queue_list); 203 204 vlan->numvtaps++; 205 vlan->numqueues++; 206 207 return 0; 208 } 209 210 static int macvtap_disable_queue(struct macvtap_queue *q) 211 { 212 struct macvlan_dev *vlan; 213 struct macvtap_queue *nq; 214 215 ASSERT_RTNL(); 216 if (!q->enabled) 217 return -EINVAL; 218 219 vlan = rtnl_dereference(q->vlan); 220 221 if (vlan) { 222 int index = q->queue_index; 223 BUG_ON(index >= vlan->numvtaps); 224 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]); 225 nq->queue_index = index; 226 227 rcu_assign_pointer(vlan->taps[index], nq); 228 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); 229 q->enabled = false; 230 231 vlan->numvtaps--; 232 } 233 234 return 0; 235 } 236 237 /* 238 * The file owning the queue got closed, give up both 239 * the reference that the files holds as well as the 240 * one from the macvlan_dev if that still exists. 241 * 242 * Using the spinlock makes sure that we don't get 243 * to the queue again after destroying it. 244 */ 245 static void macvtap_put_queue(struct macvtap_queue *q) 246 { 247 struct macvlan_dev *vlan; 248 249 rtnl_lock(); 250 vlan = rtnl_dereference(q->vlan); 251 252 if (vlan) { 253 if (q->enabled) 254 BUG_ON(macvtap_disable_queue(q)); 255 256 vlan->numqueues--; 257 RCU_INIT_POINTER(q->vlan, NULL); 258 sock_put(&q->sk); 259 list_del_init(&q->next); 260 } 261 262 rtnl_unlock(); 263 264 synchronize_rcu(); 265 sock_put(&q->sk); 266 } 267 268 /* 269 * Select a queue based on the rxq of the device on which this packet 270 * arrived. If the incoming device is not mq, calculate a flow hash 271 * to select a queue. If all fails, find the first available queue. 272 * Cache vlan->numvtaps since it can become zero during the execution 273 * of this function. 274 */ 275 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, 276 struct sk_buff *skb) 277 { 278 struct macvlan_dev *vlan = netdev_priv(dev); 279 struct macvtap_queue *tap = NULL; 280 /* Access to taps array is protected by rcu, but access to numvtaps 281 * isn't. Below we use it to lookup a queue, but treat it as a hint 282 * and validate that the result isn't NULL - in case we are 283 * racing against queue removal. 284 */ 285 int numvtaps = ACCESS_ONCE(vlan->numvtaps); 286 __u32 rxq; 287 288 if (!numvtaps) 289 goto out; 290 291 /* Check if we can use flow to select a queue */ 292 rxq = skb_get_hash(skb); 293 if (rxq) { 294 tap = rcu_dereference(vlan->taps[rxq % numvtaps]); 295 goto out; 296 } 297 298 if (likely(skb_rx_queue_recorded(skb))) { 299 rxq = skb_get_rx_queue(skb); 300 301 while (unlikely(rxq >= numvtaps)) 302 rxq -= numvtaps; 303 304 tap = rcu_dereference(vlan->taps[rxq]); 305 goto out; 306 } 307 308 tap = rcu_dereference(vlan->taps[0]); 309 out: 310 return tap; 311 } 312 313 /* 314 * The net_device is going away, give up the reference 315 * that it holds on all queues and safely set the pointer 316 * from the queues to NULL. 317 */ 318 static void macvtap_del_queues(struct net_device *dev) 319 { 320 struct macvlan_dev *vlan = netdev_priv(dev); 321 struct macvtap_queue *q, *tmp; 322 323 ASSERT_RTNL(); 324 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { 325 list_del_init(&q->next); 326 RCU_INIT_POINTER(q->vlan, NULL); 327 if (q->enabled) 328 vlan->numvtaps--; 329 vlan->numqueues--; 330 sock_put(&q->sk); 331 } 332 BUG_ON(vlan->numvtaps); 333 BUG_ON(vlan->numqueues); 334 /* guarantee that any future macvtap_set_queue will fail */ 335 vlan->numvtaps = MAX_MACVTAP_QUEUES; 336 } 337 338 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb) 339 { 340 struct sk_buff *skb = *pskb; 341 struct net_device *dev = skb->dev; 342 struct macvlan_dev *vlan; 343 struct macvtap_queue *q; 344 netdev_features_t features = TAP_FEATURES; 345 346 vlan = macvtap_get_vlan_rcu(dev); 347 if (!vlan) 348 return RX_HANDLER_PASS; 349 350 q = macvtap_get_queue(dev, skb); 351 if (!q) 352 return RX_HANDLER_PASS; 353 354 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) 355 goto drop; 356 357 skb_push(skb, ETH_HLEN); 358 359 /* Apply the forward feature mask so that we perform segmentation 360 * according to users wishes. This only works if VNET_HDR is 361 * enabled. 362 */ 363 if (q->flags & IFF_VNET_HDR) 364 features |= vlan->tap_features; 365 if (netif_needs_gso(skb, features)) { 366 struct sk_buff *segs = __skb_gso_segment(skb, features, false); 367 368 if (IS_ERR(segs)) 369 goto drop; 370 371 if (!segs) { 372 skb_queue_tail(&q->sk.sk_receive_queue, skb); 373 goto wake_up; 374 } 375 376 kfree_skb(skb); 377 while (segs) { 378 struct sk_buff *nskb = segs->next; 379 380 segs->next = NULL; 381 skb_queue_tail(&q->sk.sk_receive_queue, segs); 382 segs = nskb; 383 } 384 } else { 385 /* If we receive a partial checksum and the tap side 386 * doesn't support checksum offload, compute the checksum. 387 * Note: it doesn't matter which checksum feature to 388 * check, we either support them all or none. 389 */ 390 if (skb->ip_summed == CHECKSUM_PARTIAL && 391 !(features & NETIF_F_ALL_CSUM) && 392 skb_checksum_help(skb)) 393 goto drop; 394 skb_queue_tail(&q->sk.sk_receive_queue, skb); 395 } 396 397 wake_up: 398 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); 399 return RX_HANDLER_CONSUMED; 400 401 drop: 402 /* Count errors/drops only here, thus don't care about args. */ 403 macvlan_count_rx(vlan, 0, 0, 0); 404 kfree_skb(skb); 405 return RX_HANDLER_CONSUMED; 406 } 407 408 static int macvtap_get_minor(struct macvlan_dev *vlan) 409 { 410 int retval = -ENOMEM; 411 412 mutex_lock(&minor_lock); 413 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); 414 if (retval >= 0) { 415 vlan->minor = retval; 416 } else if (retval == -ENOSPC) { 417 printk(KERN_ERR "too many macvtap devices\n"); 418 retval = -EINVAL; 419 } 420 mutex_unlock(&minor_lock); 421 return retval < 0 ? retval : 0; 422 } 423 424 static void macvtap_free_minor(struct macvlan_dev *vlan) 425 { 426 mutex_lock(&minor_lock); 427 if (vlan->minor) { 428 idr_remove(&minor_idr, vlan->minor); 429 vlan->minor = 0; 430 } 431 mutex_unlock(&minor_lock); 432 } 433 434 static struct net_device *dev_get_by_macvtap_minor(int minor) 435 { 436 struct net_device *dev = NULL; 437 struct macvlan_dev *vlan; 438 439 mutex_lock(&minor_lock); 440 vlan = idr_find(&minor_idr, minor); 441 if (vlan) { 442 dev = vlan->dev; 443 dev_hold(dev); 444 } 445 mutex_unlock(&minor_lock); 446 return dev; 447 } 448 449 static int macvtap_newlink(struct net *src_net, 450 struct net_device *dev, 451 struct nlattr *tb[], 452 struct nlattr *data[]) 453 { 454 struct macvlan_dev *vlan = netdev_priv(dev); 455 int err; 456 457 INIT_LIST_HEAD(&vlan->queue_list); 458 459 /* Since macvlan supports all offloads by default, make 460 * tap support all offloads also. 461 */ 462 vlan->tap_features = TUN_OFFLOADS; 463 464 err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan); 465 if (err) 466 return err; 467 468 /* Don't put anything that may fail after macvlan_common_newlink 469 * because we can't undo what it does. 470 */ 471 return macvlan_common_newlink(src_net, dev, tb, data); 472 } 473 474 static void macvtap_dellink(struct net_device *dev, 475 struct list_head *head) 476 { 477 netdev_rx_handler_unregister(dev); 478 macvtap_del_queues(dev); 479 macvlan_dellink(dev, head); 480 } 481 482 static void macvtap_setup(struct net_device *dev) 483 { 484 macvlan_common_setup(dev); 485 dev->tx_queue_len = TUN_READQ_SIZE; 486 } 487 488 static struct rtnl_link_ops macvtap_link_ops __read_mostly = { 489 .kind = "macvtap", 490 .setup = macvtap_setup, 491 .newlink = macvtap_newlink, 492 .dellink = macvtap_dellink, 493 }; 494 495 496 static void macvtap_sock_write_space(struct sock *sk) 497 { 498 wait_queue_head_t *wqueue; 499 500 if (!sock_writeable(sk) || 501 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 502 return; 503 504 wqueue = sk_sleep(sk); 505 if (wqueue && waitqueue_active(wqueue)) 506 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); 507 } 508 509 static void macvtap_sock_destruct(struct sock *sk) 510 { 511 skb_queue_purge(&sk->sk_receive_queue); 512 } 513 514 static int macvtap_open(struct inode *inode, struct file *file) 515 { 516 struct net *net = current->nsproxy->net_ns; 517 struct net_device *dev; 518 struct macvtap_queue *q; 519 int err = -ENODEV; 520 521 rtnl_lock(); 522 dev = dev_get_by_macvtap_minor(iminor(inode)); 523 if (!dev) 524 goto out; 525 526 err = -ENOMEM; 527 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 528 &macvtap_proto, 0); 529 if (!q) 530 goto out; 531 532 RCU_INIT_POINTER(q->sock.wq, &q->wq); 533 init_waitqueue_head(&q->wq.wait); 534 q->sock.type = SOCK_RAW; 535 q->sock.state = SS_CONNECTED; 536 q->sock.file = file; 537 q->sock.ops = &macvtap_socket_ops; 538 sock_init_data(&q->sock, &q->sk); 539 q->sk.sk_write_space = macvtap_sock_write_space; 540 q->sk.sk_destruct = macvtap_sock_destruct; 541 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; 542 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 543 544 /* 545 * so far only KVM virtio_net uses macvtap, enable zero copy between 546 * guest kernel and host kernel when lower device supports zerocopy 547 * 548 * The macvlan supports zerocopy iff the lower device supports zero 549 * copy so we don't have to look at the lower device directly. 550 */ 551 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) 552 sock_set_flag(&q->sk, SOCK_ZEROCOPY); 553 554 err = macvtap_set_queue(dev, file, q); 555 if (err) 556 sock_put(&q->sk); 557 558 out: 559 if (dev) 560 dev_put(dev); 561 562 rtnl_unlock(); 563 return err; 564 } 565 566 static int macvtap_release(struct inode *inode, struct file *file) 567 { 568 struct macvtap_queue *q = file->private_data; 569 macvtap_put_queue(q); 570 return 0; 571 } 572 573 static unsigned int macvtap_poll(struct file *file, poll_table * wait) 574 { 575 struct macvtap_queue *q = file->private_data; 576 unsigned int mask = POLLERR; 577 578 if (!q) 579 goto out; 580 581 mask = 0; 582 poll_wait(file, &q->wq.wait, wait); 583 584 if (!skb_queue_empty(&q->sk.sk_receive_queue)) 585 mask |= POLLIN | POLLRDNORM; 586 587 if (sock_writeable(&q->sk) || 588 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && 589 sock_writeable(&q->sk))) 590 mask |= POLLOUT | POLLWRNORM; 591 592 out: 593 return mask; 594 } 595 596 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, 597 size_t len, size_t linear, 598 int noblock, int *err) 599 { 600 struct sk_buff *skb; 601 602 /* Under a page? Don't bother with paged skb. */ 603 if (prepad + len < PAGE_SIZE || !linear) 604 linear = len; 605 606 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 607 err, 0); 608 if (!skb) 609 return NULL; 610 611 skb_reserve(skb, prepad); 612 skb_put(skb, linear); 613 skb->data_len = len - linear; 614 skb->len += len - linear; 615 616 return skb; 617 } 618 619 /* 620 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should 621 * be shared with the tun/tap driver. 622 */ 623 static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q, 624 struct sk_buff *skb, 625 struct virtio_net_hdr *vnet_hdr) 626 { 627 unsigned short gso_type = 0; 628 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 629 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 630 case VIRTIO_NET_HDR_GSO_TCPV4: 631 gso_type = SKB_GSO_TCPV4; 632 break; 633 case VIRTIO_NET_HDR_GSO_TCPV6: 634 gso_type = SKB_GSO_TCPV6; 635 break; 636 case VIRTIO_NET_HDR_GSO_UDP: 637 gso_type = SKB_GSO_UDP; 638 break; 639 default: 640 return -EINVAL; 641 } 642 643 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) 644 gso_type |= SKB_GSO_TCP_ECN; 645 646 if (vnet_hdr->gso_size == 0) 647 return -EINVAL; 648 } 649 650 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 651 if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start), 652 macvtap16_to_cpu(q, vnet_hdr->csum_offset))) 653 return -EINVAL; 654 } 655 656 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 657 skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size); 658 skb_shinfo(skb)->gso_type = gso_type; 659 660 /* Header must be checked, and gso_segs computed. */ 661 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 662 skb_shinfo(skb)->gso_segs = 0; 663 } 664 return 0; 665 } 666 667 static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q, 668 const struct sk_buff *skb, 669 struct virtio_net_hdr *vnet_hdr) 670 { 671 memset(vnet_hdr, 0, sizeof(*vnet_hdr)); 672 673 if (skb_is_gso(skb)) { 674 struct skb_shared_info *sinfo = skb_shinfo(skb); 675 676 /* This is a hint as to how much should be linear. */ 677 vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb)); 678 vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size); 679 if (sinfo->gso_type & SKB_GSO_TCPV4) 680 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 681 else if (sinfo->gso_type & SKB_GSO_TCPV6) 682 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 683 else if (sinfo->gso_type & SKB_GSO_UDP) 684 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP; 685 else 686 BUG(); 687 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 688 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 689 } else 690 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 691 692 if (skb->ip_summed == CHECKSUM_PARTIAL) { 693 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 694 if (skb_vlan_tag_present(skb)) 695 vnet_hdr->csum_start = cpu_to_macvtap16(q, 696 skb_checksum_start_offset(skb) + VLAN_HLEN); 697 else 698 vnet_hdr->csum_start = cpu_to_macvtap16(q, 699 skb_checksum_start_offset(skb)); 700 vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset); 701 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 702 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; 703 } /* else everything is zero */ 704 } 705 706 /* Neighbour code has some assumptions on HH_DATA_MOD alignment */ 707 #define MACVTAP_RESERVE HH_DATA_OFF(ETH_HLEN) 708 709 /* Get packet from user space buffer */ 710 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 711 struct iov_iter *from, int noblock) 712 { 713 int good_linear = SKB_MAX_HEAD(MACVTAP_RESERVE); 714 struct sk_buff *skb; 715 struct macvlan_dev *vlan; 716 unsigned long total_len = iov_iter_count(from); 717 unsigned long len = total_len; 718 int err; 719 struct virtio_net_hdr vnet_hdr = { 0 }; 720 int vnet_hdr_len = 0; 721 int copylen = 0; 722 bool zerocopy = false; 723 size_t linear; 724 ssize_t n; 725 726 if (q->flags & IFF_VNET_HDR) { 727 vnet_hdr_len = q->vnet_hdr_sz; 728 729 err = -EINVAL; 730 if (len < vnet_hdr_len) 731 goto err; 732 len -= vnet_hdr_len; 733 734 err = -EFAULT; 735 n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from); 736 if (n != sizeof(vnet_hdr)) 737 goto err; 738 iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr)); 739 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 740 macvtap16_to_cpu(q, vnet_hdr.csum_start) + 741 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > 742 macvtap16_to_cpu(q, vnet_hdr.hdr_len)) 743 vnet_hdr.hdr_len = cpu_to_macvtap16(q, 744 macvtap16_to_cpu(q, vnet_hdr.csum_start) + 745 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2); 746 err = -EINVAL; 747 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len) 748 goto err; 749 } 750 751 err = -EINVAL; 752 if (unlikely(len < ETH_HLEN)) 753 goto err; 754 755 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { 756 struct iov_iter i; 757 758 copylen = vnet_hdr.hdr_len ? 759 macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; 760 if (copylen > good_linear) 761 copylen = good_linear; 762 linear = copylen; 763 i = *from; 764 iov_iter_advance(&i, copylen); 765 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 766 zerocopy = true; 767 } 768 769 if (!zerocopy) { 770 copylen = len; 771 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear) 772 linear = good_linear; 773 else 774 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); 775 } 776 777 skb = macvtap_alloc_skb(&q->sk, MACVTAP_RESERVE, copylen, 778 linear, noblock, &err); 779 if (!skb) 780 goto err; 781 782 if (zerocopy) 783 err = zerocopy_sg_from_iter(skb, from); 784 else { 785 err = skb_copy_datagram_from_iter(skb, 0, from, len); 786 if (!err && m && m->msg_control) { 787 struct ubuf_info *uarg = m->msg_control; 788 uarg->callback(uarg, false); 789 } 790 } 791 792 if (err) 793 goto err_kfree; 794 795 skb_set_network_header(skb, ETH_HLEN); 796 skb_reset_mac_header(skb); 797 skb->protocol = eth_hdr(skb)->h_proto; 798 799 if (vnet_hdr_len) { 800 err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr); 801 if (err) 802 goto err_kfree; 803 } 804 805 skb_probe_transport_header(skb, ETH_HLEN); 806 807 rcu_read_lock(); 808 vlan = rcu_dereference(q->vlan); 809 /* copy skb_ubuf_info for callback when skb has no error */ 810 if (zerocopy) { 811 skb_shinfo(skb)->destructor_arg = m->msg_control; 812 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 813 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 814 } 815 if (vlan) { 816 skb->dev = vlan->dev; 817 dev_queue_xmit(skb); 818 } else { 819 kfree_skb(skb); 820 } 821 rcu_read_unlock(); 822 823 return total_len; 824 825 err_kfree: 826 kfree_skb(skb); 827 828 err: 829 rcu_read_lock(); 830 vlan = rcu_dereference(q->vlan); 831 if (vlan) 832 this_cpu_inc(vlan->pcpu_stats->tx_dropped); 833 rcu_read_unlock(); 834 835 return err; 836 } 837 838 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from) 839 { 840 struct file *file = iocb->ki_filp; 841 struct macvtap_queue *q = file->private_data; 842 843 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK); 844 } 845 846 /* Put packet to the user space buffer */ 847 static ssize_t macvtap_put_user(struct macvtap_queue *q, 848 const struct sk_buff *skb, 849 struct iov_iter *iter) 850 { 851 int ret; 852 int vnet_hdr_len = 0; 853 int vlan_offset = 0; 854 int total; 855 856 if (q->flags & IFF_VNET_HDR) { 857 struct virtio_net_hdr vnet_hdr; 858 vnet_hdr_len = q->vnet_hdr_sz; 859 if (iov_iter_count(iter) < vnet_hdr_len) 860 return -EINVAL; 861 862 macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr); 863 864 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) != 865 sizeof(vnet_hdr)) 866 return -EFAULT; 867 868 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr)); 869 } 870 total = vnet_hdr_len; 871 total += skb->len; 872 873 if (skb_vlan_tag_present(skb)) { 874 struct { 875 __be16 h_vlan_proto; 876 __be16 h_vlan_TCI; 877 } veth; 878 veth.h_vlan_proto = skb->vlan_proto; 879 veth.h_vlan_TCI = htons(skb_vlan_tag_get(skb)); 880 881 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 882 total += VLAN_HLEN; 883 884 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 885 if (ret || !iov_iter_count(iter)) 886 goto done; 887 888 ret = copy_to_iter(&veth, sizeof(veth), iter); 889 if (ret != sizeof(veth) || !iov_iter_count(iter)) 890 goto done; 891 } 892 893 ret = skb_copy_datagram_iter(skb, vlan_offset, iter, 894 skb->len - vlan_offset); 895 896 done: 897 return ret ? ret : total; 898 } 899 900 static ssize_t macvtap_do_read(struct macvtap_queue *q, 901 struct iov_iter *to, 902 int noblock) 903 { 904 DEFINE_WAIT(wait); 905 struct sk_buff *skb; 906 ssize_t ret = 0; 907 908 if (!iov_iter_count(to)) 909 return 0; 910 911 while (1) { 912 if (!noblock) 913 prepare_to_wait(sk_sleep(&q->sk), &wait, 914 TASK_INTERRUPTIBLE); 915 916 /* Read frames from the queue */ 917 skb = skb_dequeue(&q->sk.sk_receive_queue); 918 if (skb) 919 break; 920 if (noblock) { 921 ret = -EAGAIN; 922 break; 923 } 924 if (signal_pending(current)) { 925 ret = -ERESTARTSYS; 926 break; 927 } 928 /* Nothing to read, let's sleep */ 929 schedule(); 930 } 931 if (skb) { 932 ret = macvtap_put_user(q, skb, to); 933 if (unlikely(ret < 0)) 934 kfree_skb(skb); 935 else 936 consume_skb(skb); 937 } 938 if (!noblock) 939 finish_wait(sk_sleep(&q->sk), &wait); 940 return ret; 941 } 942 943 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to) 944 { 945 struct file *file = iocb->ki_filp; 946 struct macvtap_queue *q = file->private_data; 947 ssize_t len = iov_iter_count(to), ret; 948 949 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK); 950 ret = min_t(ssize_t, ret, len); 951 if (ret > 0) 952 iocb->ki_pos = ret; 953 return ret; 954 } 955 956 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) 957 { 958 struct macvlan_dev *vlan; 959 960 ASSERT_RTNL(); 961 vlan = rtnl_dereference(q->vlan); 962 if (vlan) 963 dev_hold(vlan->dev); 964 965 return vlan; 966 } 967 968 static void macvtap_put_vlan(struct macvlan_dev *vlan) 969 { 970 dev_put(vlan->dev); 971 } 972 973 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) 974 { 975 struct macvtap_queue *q = file->private_data; 976 struct macvlan_dev *vlan; 977 int ret; 978 979 vlan = macvtap_get_vlan(q); 980 if (!vlan) 981 return -EINVAL; 982 983 if (flags & IFF_ATTACH_QUEUE) 984 ret = macvtap_enable_queue(vlan->dev, file, q); 985 else if (flags & IFF_DETACH_QUEUE) 986 ret = macvtap_disable_queue(q); 987 else 988 ret = -EINVAL; 989 990 macvtap_put_vlan(vlan); 991 return ret; 992 } 993 994 static int set_offload(struct macvtap_queue *q, unsigned long arg) 995 { 996 struct macvlan_dev *vlan; 997 netdev_features_t features; 998 netdev_features_t feature_mask = 0; 999 1000 vlan = rtnl_dereference(q->vlan); 1001 if (!vlan) 1002 return -ENOLINK; 1003 1004 features = vlan->dev->features; 1005 1006 if (arg & TUN_F_CSUM) { 1007 feature_mask = NETIF_F_HW_CSUM; 1008 1009 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { 1010 if (arg & TUN_F_TSO_ECN) 1011 feature_mask |= NETIF_F_TSO_ECN; 1012 if (arg & TUN_F_TSO4) 1013 feature_mask |= NETIF_F_TSO; 1014 if (arg & TUN_F_TSO6) 1015 feature_mask |= NETIF_F_TSO6; 1016 } 1017 1018 if (arg & TUN_F_UFO) 1019 feature_mask |= NETIF_F_UFO; 1020 } 1021 1022 /* tun/tap driver inverts the usage for TSO offloads, where 1023 * setting the TSO bit means that the userspace wants to 1024 * accept TSO frames and turning it off means that user space 1025 * does not support TSO. 1026 * For macvtap, we have to invert it to mean the same thing. 1027 * When user space turns off TSO, we turn off GSO/LRO so that 1028 * user-space will not receive TSO frames. 1029 */ 1030 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6 | NETIF_F_UFO)) 1031 features |= RX_OFFLOADS; 1032 else 1033 features &= ~RX_OFFLOADS; 1034 1035 /* tap_features are the same as features on tun/tap and 1036 * reflect user expectations. 1037 */ 1038 vlan->tap_features = feature_mask; 1039 vlan->set_features = features; 1040 netdev_update_features(vlan->dev); 1041 1042 return 0; 1043 } 1044 1045 /* 1046 * provide compatibility with generic tun/tap interface 1047 */ 1048 static long macvtap_ioctl(struct file *file, unsigned int cmd, 1049 unsigned long arg) 1050 { 1051 struct macvtap_queue *q = file->private_data; 1052 struct macvlan_dev *vlan; 1053 void __user *argp = (void __user *)arg; 1054 struct ifreq __user *ifr = argp; 1055 unsigned int __user *up = argp; 1056 unsigned short u; 1057 int __user *sp = argp; 1058 struct sockaddr sa; 1059 int s; 1060 int ret; 1061 1062 switch (cmd) { 1063 case TUNSETIFF: 1064 /* ignore the name, just look at flags */ 1065 if (get_user(u, &ifr->ifr_flags)) 1066 return -EFAULT; 1067 1068 ret = 0; 1069 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP)) 1070 ret = -EINVAL; 1071 else 1072 q->flags = (q->flags & ~MACVTAP_FEATURES) | u; 1073 1074 return ret; 1075 1076 case TUNGETIFF: 1077 rtnl_lock(); 1078 vlan = macvtap_get_vlan(q); 1079 if (!vlan) { 1080 rtnl_unlock(); 1081 return -ENOLINK; 1082 } 1083 1084 ret = 0; 1085 u = q->flags; 1086 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1087 put_user(u, &ifr->ifr_flags)) 1088 ret = -EFAULT; 1089 macvtap_put_vlan(vlan); 1090 rtnl_unlock(); 1091 return ret; 1092 1093 case TUNSETQUEUE: 1094 if (get_user(u, &ifr->ifr_flags)) 1095 return -EFAULT; 1096 rtnl_lock(); 1097 ret = macvtap_ioctl_set_queue(file, u); 1098 rtnl_unlock(); 1099 return ret; 1100 1101 case TUNGETFEATURES: 1102 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up)) 1103 return -EFAULT; 1104 return 0; 1105 1106 case TUNSETSNDBUF: 1107 if (get_user(u, up)) 1108 return -EFAULT; 1109 1110 q->sk.sk_sndbuf = u; 1111 return 0; 1112 1113 case TUNGETVNETHDRSZ: 1114 s = q->vnet_hdr_sz; 1115 if (put_user(s, sp)) 1116 return -EFAULT; 1117 return 0; 1118 1119 case TUNSETVNETHDRSZ: 1120 if (get_user(s, sp)) 1121 return -EFAULT; 1122 if (s < (int)sizeof(struct virtio_net_hdr)) 1123 return -EINVAL; 1124 1125 q->vnet_hdr_sz = s; 1126 return 0; 1127 1128 case TUNGETVNETLE: 1129 s = !!(q->flags & MACVTAP_VNET_LE); 1130 if (put_user(s, sp)) 1131 return -EFAULT; 1132 return 0; 1133 1134 case TUNSETVNETLE: 1135 if (get_user(s, sp)) 1136 return -EFAULT; 1137 if (s) 1138 q->flags |= MACVTAP_VNET_LE; 1139 else 1140 q->flags &= ~MACVTAP_VNET_LE; 1141 return 0; 1142 1143 case TUNGETVNETBE: 1144 return macvtap_get_vnet_be(q, sp); 1145 1146 case TUNSETVNETBE: 1147 return macvtap_set_vnet_be(q, sp); 1148 1149 case TUNSETOFFLOAD: 1150 /* let the user check for future flags */ 1151 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 1152 TUN_F_TSO_ECN | TUN_F_UFO)) 1153 return -EINVAL; 1154 1155 rtnl_lock(); 1156 ret = set_offload(q, arg); 1157 rtnl_unlock(); 1158 return ret; 1159 1160 case SIOCGIFHWADDR: 1161 rtnl_lock(); 1162 vlan = macvtap_get_vlan(q); 1163 if (!vlan) { 1164 rtnl_unlock(); 1165 return -ENOLINK; 1166 } 1167 ret = 0; 1168 u = vlan->dev->type; 1169 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1170 copy_to_user(&ifr->ifr_hwaddr.sa_data, vlan->dev->dev_addr, ETH_ALEN) || 1171 put_user(u, &ifr->ifr_hwaddr.sa_family)) 1172 ret = -EFAULT; 1173 macvtap_put_vlan(vlan); 1174 rtnl_unlock(); 1175 return ret; 1176 1177 case SIOCSIFHWADDR: 1178 if (copy_from_user(&sa, &ifr->ifr_hwaddr, sizeof(sa))) 1179 return -EFAULT; 1180 rtnl_lock(); 1181 vlan = macvtap_get_vlan(q); 1182 if (!vlan) { 1183 rtnl_unlock(); 1184 return -ENOLINK; 1185 } 1186 ret = dev_set_mac_address(vlan->dev, &sa); 1187 macvtap_put_vlan(vlan); 1188 rtnl_unlock(); 1189 return ret; 1190 1191 default: 1192 return -EINVAL; 1193 } 1194 } 1195 1196 #ifdef CONFIG_COMPAT 1197 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, 1198 unsigned long arg) 1199 { 1200 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1201 } 1202 #endif 1203 1204 static const struct file_operations macvtap_fops = { 1205 .owner = THIS_MODULE, 1206 .open = macvtap_open, 1207 .release = macvtap_release, 1208 .read_iter = macvtap_read_iter, 1209 .write_iter = macvtap_write_iter, 1210 .poll = macvtap_poll, 1211 .llseek = no_llseek, 1212 .unlocked_ioctl = macvtap_ioctl, 1213 #ifdef CONFIG_COMPAT 1214 .compat_ioctl = macvtap_compat_ioctl, 1215 #endif 1216 }; 1217 1218 static int macvtap_sendmsg(struct socket *sock, struct msghdr *m, 1219 size_t total_len) 1220 { 1221 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1222 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT); 1223 } 1224 1225 static int macvtap_recvmsg(struct socket *sock, struct msghdr *m, 1226 size_t total_len, int flags) 1227 { 1228 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1229 int ret; 1230 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1231 return -EINVAL; 1232 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT); 1233 if (ret > total_len) { 1234 m->msg_flags |= MSG_TRUNC; 1235 ret = flags & MSG_TRUNC ? ret : total_len; 1236 } 1237 return ret; 1238 } 1239 1240 /* Ops structure to mimic raw sockets with tun */ 1241 static const struct proto_ops macvtap_socket_ops = { 1242 .sendmsg = macvtap_sendmsg, 1243 .recvmsg = macvtap_recvmsg, 1244 }; 1245 1246 /* Get an underlying socket object from tun file. Returns error unless file is 1247 * attached to a device. The returned object works like a packet socket, it 1248 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1249 * holding a reference to the file for as long as the socket is in use. */ 1250 struct socket *macvtap_get_socket(struct file *file) 1251 { 1252 struct macvtap_queue *q; 1253 if (file->f_op != &macvtap_fops) 1254 return ERR_PTR(-EINVAL); 1255 q = file->private_data; 1256 if (!q) 1257 return ERR_PTR(-EBADFD); 1258 return &q->sock; 1259 } 1260 EXPORT_SYMBOL_GPL(macvtap_get_socket); 1261 1262 static int macvtap_device_event(struct notifier_block *unused, 1263 unsigned long event, void *ptr) 1264 { 1265 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1266 struct macvlan_dev *vlan; 1267 struct device *classdev; 1268 dev_t devt; 1269 int err; 1270 1271 if (dev->rtnl_link_ops != &macvtap_link_ops) 1272 return NOTIFY_DONE; 1273 1274 vlan = netdev_priv(dev); 1275 1276 switch (event) { 1277 case NETDEV_REGISTER: 1278 /* Create the device node here after the network device has 1279 * been registered but before register_netdevice has 1280 * finished running. 1281 */ 1282 err = macvtap_get_minor(vlan); 1283 if (err) 1284 return notifier_from_errno(err); 1285 1286 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1287 classdev = device_create(macvtap_class, &dev->dev, devt, 1288 dev, "tap%d", dev->ifindex); 1289 if (IS_ERR(classdev)) { 1290 macvtap_free_minor(vlan); 1291 return notifier_from_errno(PTR_ERR(classdev)); 1292 } 1293 break; 1294 case NETDEV_UNREGISTER: 1295 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1296 device_destroy(macvtap_class, devt); 1297 macvtap_free_minor(vlan); 1298 break; 1299 } 1300 1301 return NOTIFY_DONE; 1302 } 1303 1304 static struct notifier_block macvtap_notifier_block __read_mostly = { 1305 .notifier_call = macvtap_device_event, 1306 }; 1307 1308 static int macvtap_init(void) 1309 { 1310 int err; 1311 1312 err = alloc_chrdev_region(&macvtap_major, 0, 1313 MACVTAP_NUM_DEVS, "macvtap"); 1314 if (err) 1315 goto out1; 1316 1317 cdev_init(&macvtap_cdev, &macvtap_fops); 1318 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); 1319 if (err) 1320 goto out2; 1321 1322 macvtap_class = class_create(THIS_MODULE, "macvtap"); 1323 if (IS_ERR(macvtap_class)) { 1324 err = PTR_ERR(macvtap_class); 1325 goto out3; 1326 } 1327 1328 err = register_netdevice_notifier(&macvtap_notifier_block); 1329 if (err) 1330 goto out4; 1331 1332 err = macvlan_link_register(&macvtap_link_ops); 1333 if (err) 1334 goto out5; 1335 1336 return 0; 1337 1338 out5: 1339 unregister_netdevice_notifier(&macvtap_notifier_block); 1340 out4: 1341 class_unregister(macvtap_class); 1342 out3: 1343 cdev_del(&macvtap_cdev); 1344 out2: 1345 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1346 out1: 1347 return err; 1348 } 1349 module_init(macvtap_init); 1350 1351 static void macvtap_exit(void) 1352 { 1353 rtnl_link_unregister(&macvtap_link_ops); 1354 unregister_netdevice_notifier(&macvtap_notifier_block); 1355 class_unregister(macvtap_class); 1356 cdev_del(&macvtap_cdev); 1357 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1358 } 1359 module_exit(macvtap_exit); 1360 1361 MODULE_ALIAS_RTNL_LINK("macvtap"); 1362 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 1363 MODULE_LICENSE("GPL"); 1364