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