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/ipv6.h> 21 #include <net/net_namespace.h> 22 #include <net/rtnetlink.h> 23 #include <net/sock.h> 24 #include <linux/virtio_net.h> 25 26 /* 27 * A macvtap queue is the central object of this driver, it connects 28 * an open character device to a macvlan interface. There can be 29 * multiple queues on one interface, which map back to queues 30 * implemented in hardware on the underlying device. 31 * 32 * macvtap_proto is used to allocate queues through the sock allocation 33 * mechanism. 34 * 35 */ 36 struct macvtap_queue { 37 struct sock sk; 38 struct socket sock; 39 struct socket_wq wq; 40 int vnet_hdr_sz; 41 struct macvlan_dev __rcu *vlan; 42 struct file *file; 43 unsigned int flags; 44 u16 queue_index; 45 bool enabled; 46 struct list_head next; 47 }; 48 49 #define MACVTAP_FEATURES (IFF_VNET_HDR | IFF_MULTI_QUEUE) 50 51 #define MACVTAP_VNET_LE 0x80000000 52 53 static inline u16 macvtap16_to_cpu(struct macvtap_queue *q, __virtio16 val) 54 { 55 return __virtio16_to_cpu(q->flags & MACVTAP_VNET_LE, val); 56 } 57 58 static inline __virtio16 cpu_to_macvtap16(struct macvtap_queue *q, u16 val) 59 { 60 return __cpu_to_virtio16(q->flags & MACVTAP_VNET_LE, val); 61 } 62 63 static struct proto macvtap_proto = { 64 .name = "macvtap", 65 .owner = THIS_MODULE, 66 .obj_size = sizeof (struct macvtap_queue), 67 }; 68 69 /* 70 * Variables for dealing with macvtaps device numbers. 71 */ 72 static dev_t macvtap_major; 73 #define MACVTAP_NUM_DEVS (1U << MINORBITS) 74 static DEFINE_MUTEX(minor_lock); 75 static DEFINE_IDR(minor_idr); 76 77 #define GOODCOPY_LEN 128 78 static struct class *macvtap_class; 79 static struct cdev macvtap_cdev; 80 81 static const struct proto_ops macvtap_socket_ops; 82 83 #define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \ 84 NETIF_F_TSO6) 85 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO) 86 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG) 87 88 static struct macvlan_dev *macvtap_get_vlan_rcu(const struct net_device *dev) 89 { 90 return rcu_dereference(dev->rx_handler_data); 91 } 92 93 /* 94 * RCU usage: 95 * The macvtap_queue and the macvlan_dev are loosely coupled, the 96 * pointers from one to the other can only be read while rcu_read_lock 97 * or rtnl is held. 98 * 99 * Both the file and the macvlan_dev hold a reference on the macvtap_queue 100 * through sock_hold(&q->sk). When the macvlan_dev goes away first, 101 * q->vlan becomes inaccessible. When the files gets closed, 102 * macvtap_get_queue() fails. 103 * 104 * There may still be references to the struct sock inside of the 105 * queue from outbound SKBs, but these never reference back to the 106 * file or the dev. The data structure is freed through __sk_free 107 * when both our references and any pending SKBs are gone. 108 */ 109 110 static int macvtap_enable_queue(struct net_device *dev, struct file *file, 111 struct macvtap_queue *q) 112 { 113 struct macvlan_dev *vlan = netdev_priv(dev); 114 int err = -EINVAL; 115 116 ASSERT_RTNL(); 117 118 if (q->enabled) 119 goto out; 120 121 err = 0; 122 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 123 q->queue_index = vlan->numvtaps; 124 q->enabled = true; 125 126 vlan->numvtaps++; 127 out: 128 return err; 129 } 130 131 /* Requires RTNL */ 132 static int macvtap_set_queue(struct net_device *dev, struct file *file, 133 struct macvtap_queue *q) 134 { 135 struct macvlan_dev *vlan = netdev_priv(dev); 136 137 if (vlan->numqueues == MAX_MACVTAP_QUEUES) 138 return -EBUSY; 139 140 rcu_assign_pointer(q->vlan, vlan); 141 rcu_assign_pointer(vlan->taps[vlan->numvtaps], q); 142 sock_hold(&q->sk); 143 144 q->file = file; 145 q->queue_index = vlan->numvtaps; 146 q->enabled = true; 147 file->private_data = q; 148 list_add_tail(&q->next, &vlan->queue_list); 149 150 vlan->numvtaps++; 151 vlan->numqueues++; 152 153 return 0; 154 } 155 156 static int macvtap_disable_queue(struct macvtap_queue *q) 157 { 158 struct macvlan_dev *vlan; 159 struct macvtap_queue *nq; 160 161 ASSERT_RTNL(); 162 if (!q->enabled) 163 return -EINVAL; 164 165 vlan = rtnl_dereference(q->vlan); 166 167 if (vlan) { 168 int index = q->queue_index; 169 BUG_ON(index >= vlan->numvtaps); 170 nq = rtnl_dereference(vlan->taps[vlan->numvtaps - 1]); 171 nq->queue_index = index; 172 173 rcu_assign_pointer(vlan->taps[index], nq); 174 RCU_INIT_POINTER(vlan->taps[vlan->numvtaps - 1], NULL); 175 q->enabled = false; 176 177 vlan->numvtaps--; 178 } 179 180 return 0; 181 } 182 183 /* 184 * The file owning the queue got closed, give up both 185 * the reference that the files holds as well as the 186 * one from the macvlan_dev if that still exists. 187 * 188 * Using the spinlock makes sure that we don't get 189 * to the queue again after destroying it. 190 */ 191 static void macvtap_put_queue(struct macvtap_queue *q) 192 { 193 struct macvlan_dev *vlan; 194 195 rtnl_lock(); 196 vlan = rtnl_dereference(q->vlan); 197 198 if (vlan) { 199 if (q->enabled) 200 BUG_ON(macvtap_disable_queue(q)); 201 202 vlan->numqueues--; 203 RCU_INIT_POINTER(q->vlan, NULL); 204 sock_put(&q->sk); 205 list_del_init(&q->next); 206 } 207 208 rtnl_unlock(); 209 210 synchronize_rcu(); 211 sock_put(&q->sk); 212 } 213 214 /* 215 * Select a queue based on the rxq of the device on which this packet 216 * arrived. If the incoming device is not mq, calculate a flow hash 217 * to select a queue. If all fails, find the first available queue. 218 * Cache vlan->numvtaps since it can become zero during the execution 219 * of this function. 220 */ 221 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev, 222 struct sk_buff *skb) 223 { 224 struct macvlan_dev *vlan = netdev_priv(dev); 225 struct macvtap_queue *tap = NULL; 226 /* Access to taps array is protected by rcu, but access to numvtaps 227 * isn't. Below we use it to lookup a queue, but treat it as a hint 228 * and validate that the result isn't NULL - in case we are 229 * racing against queue removal. 230 */ 231 int numvtaps = ACCESS_ONCE(vlan->numvtaps); 232 __u32 rxq; 233 234 if (!numvtaps) 235 goto out; 236 237 /* Check if we can use flow to select a queue */ 238 rxq = skb_get_hash(skb); 239 if (rxq) { 240 tap = rcu_dereference(vlan->taps[rxq % numvtaps]); 241 goto out; 242 } 243 244 if (likely(skb_rx_queue_recorded(skb))) { 245 rxq = skb_get_rx_queue(skb); 246 247 while (unlikely(rxq >= numvtaps)) 248 rxq -= numvtaps; 249 250 tap = rcu_dereference(vlan->taps[rxq]); 251 goto out; 252 } 253 254 tap = rcu_dereference(vlan->taps[0]); 255 out: 256 return tap; 257 } 258 259 /* 260 * The net_device is going away, give up the reference 261 * that it holds on all queues and safely set the pointer 262 * from the queues to NULL. 263 */ 264 static void macvtap_del_queues(struct net_device *dev) 265 { 266 struct macvlan_dev *vlan = netdev_priv(dev); 267 struct macvtap_queue *q, *tmp, *qlist[MAX_MACVTAP_QUEUES]; 268 int i, j = 0; 269 270 ASSERT_RTNL(); 271 list_for_each_entry_safe(q, tmp, &vlan->queue_list, next) { 272 list_del_init(&q->next); 273 qlist[j++] = q; 274 RCU_INIT_POINTER(q->vlan, NULL); 275 if (q->enabled) 276 vlan->numvtaps--; 277 vlan->numqueues--; 278 } 279 for (i = 0; i < vlan->numvtaps; i++) 280 RCU_INIT_POINTER(vlan->taps[i], NULL); 281 BUG_ON(vlan->numvtaps); 282 BUG_ON(vlan->numqueues); 283 /* guarantee that any future macvtap_set_queue will fail */ 284 vlan->numvtaps = MAX_MACVTAP_QUEUES; 285 286 for (--j; j >= 0; j--) 287 sock_put(&qlist[j]->sk); 288 } 289 290 static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb) 291 { 292 struct sk_buff *skb = *pskb; 293 struct net_device *dev = skb->dev; 294 struct macvlan_dev *vlan; 295 struct macvtap_queue *q; 296 netdev_features_t features = TAP_FEATURES; 297 298 vlan = macvtap_get_vlan_rcu(dev); 299 if (!vlan) 300 return RX_HANDLER_PASS; 301 302 q = macvtap_get_queue(dev, skb); 303 if (!q) 304 return RX_HANDLER_PASS; 305 306 if (skb_queue_len(&q->sk.sk_receive_queue) >= dev->tx_queue_len) 307 goto drop; 308 309 skb_push(skb, ETH_HLEN); 310 311 /* Apply the forward feature mask so that we perform segmentation 312 * according to users wishes. This only works if VNET_HDR is 313 * enabled. 314 */ 315 if (q->flags & IFF_VNET_HDR) 316 features |= vlan->tap_features; 317 if (netif_needs_gso(dev, skb, features)) { 318 struct sk_buff *segs = __skb_gso_segment(skb, features, false); 319 320 if (IS_ERR(segs)) 321 goto drop; 322 323 if (!segs) { 324 skb_queue_tail(&q->sk.sk_receive_queue, skb); 325 goto wake_up; 326 } 327 328 kfree_skb(skb); 329 while (segs) { 330 struct sk_buff *nskb = segs->next; 331 332 segs->next = NULL; 333 skb_queue_tail(&q->sk.sk_receive_queue, segs); 334 segs = nskb; 335 } 336 } else { 337 /* If we receive a partial checksum and the tap side 338 * doesn't support checksum offload, compute the checksum. 339 * Note: it doesn't matter which checksum feature to 340 * check, we either support them all or none. 341 */ 342 if (skb->ip_summed == CHECKSUM_PARTIAL && 343 !(features & NETIF_F_ALL_CSUM) && 344 skb_checksum_help(skb)) 345 goto drop; 346 skb_queue_tail(&q->sk.sk_receive_queue, skb); 347 } 348 349 wake_up: 350 wake_up_interruptible_poll(sk_sleep(&q->sk), POLLIN | POLLRDNORM | POLLRDBAND); 351 return RX_HANDLER_CONSUMED; 352 353 drop: 354 /* Count errors/drops only here, thus don't care about args. */ 355 macvlan_count_rx(vlan, 0, 0, 0); 356 kfree_skb(skb); 357 return RX_HANDLER_CONSUMED; 358 } 359 360 static int macvtap_get_minor(struct macvlan_dev *vlan) 361 { 362 int retval = -ENOMEM; 363 364 mutex_lock(&minor_lock); 365 retval = idr_alloc(&minor_idr, vlan, 1, MACVTAP_NUM_DEVS, GFP_KERNEL); 366 if (retval >= 0) { 367 vlan->minor = retval; 368 } else if (retval == -ENOSPC) { 369 printk(KERN_ERR "too many macvtap devices\n"); 370 retval = -EINVAL; 371 } 372 mutex_unlock(&minor_lock); 373 return retval < 0 ? retval : 0; 374 } 375 376 static void macvtap_free_minor(struct macvlan_dev *vlan) 377 { 378 mutex_lock(&minor_lock); 379 if (vlan->minor) { 380 idr_remove(&minor_idr, vlan->minor); 381 vlan->minor = 0; 382 } 383 mutex_unlock(&minor_lock); 384 } 385 386 static struct net_device *dev_get_by_macvtap_minor(int minor) 387 { 388 struct net_device *dev = NULL; 389 struct macvlan_dev *vlan; 390 391 mutex_lock(&minor_lock); 392 vlan = idr_find(&minor_idr, minor); 393 if (vlan) { 394 dev = vlan->dev; 395 dev_hold(dev); 396 } 397 mutex_unlock(&minor_lock); 398 return dev; 399 } 400 401 static int macvtap_newlink(struct net *src_net, 402 struct net_device *dev, 403 struct nlattr *tb[], 404 struct nlattr *data[]) 405 { 406 struct macvlan_dev *vlan = netdev_priv(dev); 407 int err; 408 409 INIT_LIST_HEAD(&vlan->queue_list); 410 411 /* Since macvlan supports all offloads by default, make 412 * tap support all offloads also. 413 */ 414 vlan->tap_features = TUN_OFFLOADS; 415 416 err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan); 417 if (err) 418 return err; 419 420 /* Don't put anything that may fail after macvlan_common_newlink 421 * because we can't undo what it does. 422 */ 423 return macvlan_common_newlink(src_net, dev, tb, data); 424 } 425 426 static void macvtap_dellink(struct net_device *dev, 427 struct list_head *head) 428 { 429 netdev_rx_handler_unregister(dev); 430 macvtap_del_queues(dev); 431 macvlan_dellink(dev, head); 432 } 433 434 static void macvtap_setup(struct net_device *dev) 435 { 436 macvlan_common_setup(dev); 437 dev->tx_queue_len = TUN_READQ_SIZE; 438 } 439 440 static struct rtnl_link_ops macvtap_link_ops __read_mostly = { 441 .kind = "macvtap", 442 .setup = macvtap_setup, 443 .newlink = macvtap_newlink, 444 .dellink = macvtap_dellink, 445 }; 446 447 448 static void macvtap_sock_write_space(struct sock *sk) 449 { 450 wait_queue_head_t *wqueue; 451 452 if (!sock_writeable(sk) || 453 !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags)) 454 return; 455 456 wqueue = sk_sleep(sk); 457 if (wqueue && waitqueue_active(wqueue)) 458 wake_up_interruptible_poll(wqueue, POLLOUT | POLLWRNORM | POLLWRBAND); 459 } 460 461 static void macvtap_sock_destruct(struct sock *sk) 462 { 463 skb_queue_purge(&sk->sk_receive_queue); 464 } 465 466 static int macvtap_open(struct inode *inode, struct file *file) 467 { 468 struct net *net = current->nsproxy->net_ns; 469 struct net_device *dev; 470 struct macvtap_queue *q; 471 int err = -ENODEV; 472 473 rtnl_lock(); 474 dev = dev_get_by_macvtap_minor(iminor(inode)); 475 if (!dev) 476 goto out; 477 478 err = -ENOMEM; 479 q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL, 480 &macvtap_proto); 481 if (!q) 482 goto out; 483 484 RCU_INIT_POINTER(q->sock.wq, &q->wq); 485 init_waitqueue_head(&q->wq.wait); 486 q->sock.type = SOCK_RAW; 487 q->sock.state = SS_CONNECTED; 488 q->sock.file = file; 489 q->sock.ops = &macvtap_socket_ops; 490 sock_init_data(&q->sock, &q->sk); 491 q->sk.sk_write_space = macvtap_sock_write_space; 492 q->sk.sk_destruct = macvtap_sock_destruct; 493 q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP; 494 q->vnet_hdr_sz = sizeof(struct virtio_net_hdr); 495 496 /* 497 * so far only KVM virtio_net uses macvtap, enable zero copy between 498 * guest kernel and host kernel when lower device supports zerocopy 499 * 500 * The macvlan supports zerocopy iff the lower device supports zero 501 * copy so we don't have to look at the lower device directly. 502 */ 503 if ((dev->features & NETIF_F_HIGHDMA) && (dev->features & NETIF_F_SG)) 504 sock_set_flag(&q->sk, SOCK_ZEROCOPY); 505 506 err = macvtap_set_queue(dev, file, q); 507 if (err) 508 sock_put(&q->sk); 509 510 out: 511 if (dev) 512 dev_put(dev); 513 514 rtnl_unlock(); 515 return err; 516 } 517 518 static int macvtap_release(struct inode *inode, struct file *file) 519 { 520 struct macvtap_queue *q = file->private_data; 521 macvtap_put_queue(q); 522 return 0; 523 } 524 525 static unsigned int macvtap_poll(struct file *file, poll_table * wait) 526 { 527 struct macvtap_queue *q = file->private_data; 528 unsigned int mask = POLLERR; 529 530 if (!q) 531 goto out; 532 533 mask = 0; 534 poll_wait(file, &q->wq.wait, wait); 535 536 if (!skb_queue_empty(&q->sk.sk_receive_queue)) 537 mask |= POLLIN | POLLRDNORM; 538 539 if (sock_writeable(&q->sk) || 540 (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) && 541 sock_writeable(&q->sk))) 542 mask |= POLLOUT | POLLWRNORM; 543 544 out: 545 return mask; 546 } 547 548 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad, 549 size_t len, size_t linear, 550 int noblock, int *err) 551 { 552 struct sk_buff *skb; 553 554 /* Under a page? Don't bother with paged skb. */ 555 if (prepad + len < PAGE_SIZE || !linear) 556 linear = len; 557 558 skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock, 559 err, 0); 560 if (!skb) 561 return NULL; 562 563 skb_reserve(skb, prepad); 564 skb_put(skb, linear); 565 skb->data_len = len - linear; 566 skb->len += len - linear; 567 568 return skb; 569 } 570 571 /* 572 * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should 573 * be shared with the tun/tap driver. 574 */ 575 static int macvtap_skb_from_vnet_hdr(struct macvtap_queue *q, 576 struct sk_buff *skb, 577 struct virtio_net_hdr *vnet_hdr) 578 { 579 unsigned short gso_type = 0; 580 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 581 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) { 582 case VIRTIO_NET_HDR_GSO_TCPV4: 583 gso_type = SKB_GSO_TCPV4; 584 break; 585 case VIRTIO_NET_HDR_GSO_TCPV6: 586 gso_type = SKB_GSO_TCPV6; 587 break; 588 case VIRTIO_NET_HDR_GSO_UDP: 589 pr_warn_once("macvtap: %s: using disabled UFO feature; please fix this program\n", 590 current->comm); 591 gso_type = SKB_GSO_UDP; 592 if (skb->protocol == htons(ETH_P_IPV6)) 593 ipv6_proxy_select_ident(skb); 594 break; 595 default: 596 return -EINVAL; 597 } 598 599 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN) 600 gso_type |= SKB_GSO_TCP_ECN; 601 602 if (vnet_hdr->gso_size == 0) 603 return -EINVAL; 604 } 605 606 if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { 607 if (!skb_partial_csum_set(skb, macvtap16_to_cpu(q, vnet_hdr->csum_start), 608 macvtap16_to_cpu(q, vnet_hdr->csum_offset))) 609 return -EINVAL; 610 } 611 612 if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) { 613 skb_shinfo(skb)->gso_size = macvtap16_to_cpu(q, vnet_hdr->gso_size); 614 skb_shinfo(skb)->gso_type = gso_type; 615 616 /* Header must be checked, and gso_segs computed. */ 617 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY; 618 skb_shinfo(skb)->gso_segs = 0; 619 } 620 return 0; 621 } 622 623 static void macvtap_skb_to_vnet_hdr(struct macvtap_queue *q, 624 const struct sk_buff *skb, 625 struct virtio_net_hdr *vnet_hdr) 626 { 627 memset(vnet_hdr, 0, sizeof(*vnet_hdr)); 628 629 if (skb_is_gso(skb)) { 630 struct skb_shared_info *sinfo = skb_shinfo(skb); 631 632 /* This is a hint as to how much should be linear. */ 633 vnet_hdr->hdr_len = cpu_to_macvtap16(q, skb_headlen(skb)); 634 vnet_hdr->gso_size = cpu_to_macvtap16(q, sinfo->gso_size); 635 if (sinfo->gso_type & SKB_GSO_TCPV4) 636 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4; 637 else if (sinfo->gso_type & SKB_GSO_TCPV6) 638 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6; 639 else 640 BUG(); 641 if (sinfo->gso_type & SKB_GSO_TCP_ECN) 642 vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN; 643 } else 644 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE; 645 646 if (skb->ip_summed == CHECKSUM_PARTIAL) { 647 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM; 648 if (vlan_tx_tag_present(skb)) 649 vnet_hdr->csum_start = cpu_to_macvtap16(q, 650 skb_checksum_start_offset(skb) + VLAN_HLEN); 651 else 652 vnet_hdr->csum_start = cpu_to_macvtap16(q, 653 skb_checksum_start_offset(skb)); 654 vnet_hdr->csum_offset = cpu_to_macvtap16(q, skb->csum_offset); 655 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) { 656 vnet_hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID; 657 } /* else everything is zero */ 658 } 659 660 /* Get packet from user space buffer */ 661 static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m, 662 struct iov_iter *from, int noblock) 663 { 664 int good_linear = SKB_MAX_HEAD(NET_IP_ALIGN); 665 struct sk_buff *skb; 666 struct macvlan_dev *vlan; 667 unsigned long total_len = iov_iter_count(from); 668 unsigned long len = total_len; 669 int err; 670 struct virtio_net_hdr vnet_hdr = { 0 }; 671 int vnet_hdr_len = 0; 672 int copylen = 0; 673 bool zerocopy = false; 674 size_t linear; 675 ssize_t n; 676 677 if (q->flags & IFF_VNET_HDR) { 678 vnet_hdr_len = q->vnet_hdr_sz; 679 680 err = -EINVAL; 681 if (len < vnet_hdr_len) 682 goto err; 683 len -= vnet_hdr_len; 684 685 err = -EFAULT; 686 n = copy_from_iter(&vnet_hdr, sizeof(vnet_hdr), from); 687 if (n != sizeof(vnet_hdr)) 688 goto err; 689 iov_iter_advance(from, vnet_hdr_len - sizeof(vnet_hdr)); 690 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 691 macvtap16_to_cpu(q, vnet_hdr.csum_start) + 692 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2 > 693 macvtap16_to_cpu(q, vnet_hdr.hdr_len)) 694 vnet_hdr.hdr_len = cpu_to_macvtap16(q, 695 macvtap16_to_cpu(q, vnet_hdr.csum_start) + 696 macvtap16_to_cpu(q, vnet_hdr.csum_offset) + 2); 697 err = -EINVAL; 698 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > len) 699 goto err; 700 } 701 702 err = -EINVAL; 703 if (unlikely(len < ETH_HLEN)) 704 goto err; 705 706 if (m && m->msg_control && sock_flag(&q->sk, SOCK_ZEROCOPY)) { 707 struct iov_iter i; 708 709 copylen = vnet_hdr.hdr_len ? 710 macvtap16_to_cpu(q, vnet_hdr.hdr_len) : GOODCOPY_LEN; 711 if (copylen > good_linear) 712 copylen = good_linear; 713 linear = copylen; 714 i = *from; 715 iov_iter_advance(&i, copylen); 716 if (iov_iter_npages(&i, INT_MAX) <= MAX_SKB_FRAGS) 717 zerocopy = true; 718 } 719 720 if (!zerocopy) { 721 copylen = len; 722 if (macvtap16_to_cpu(q, vnet_hdr.hdr_len) > good_linear) 723 linear = good_linear; 724 else 725 linear = macvtap16_to_cpu(q, vnet_hdr.hdr_len); 726 } 727 728 skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, copylen, 729 linear, noblock, &err); 730 if (!skb) 731 goto err; 732 733 if (zerocopy) 734 err = zerocopy_sg_from_iter(skb, from); 735 else { 736 err = skb_copy_datagram_from_iter(skb, 0, from, len); 737 if (!err && m && m->msg_control) { 738 struct ubuf_info *uarg = m->msg_control; 739 uarg->callback(uarg, false); 740 } 741 } 742 743 if (err) 744 goto err_kfree; 745 746 skb_set_network_header(skb, ETH_HLEN); 747 skb_reset_mac_header(skb); 748 skb->protocol = eth_hdr(skb)->h_proto; 749 750 if (vnet_hdr_len) { 751 err = macvtap_skb_from_vnet_hdr(q, skb, &vnet_hdr); 752 if (err) 753 goto err_kfree; 754 } 755 756 skb_probe_transport_header(skb, ETH_HLEN); 757 758 rcu_read_lock(); 759 vlan = rcu_dereference(q->vlan); 760 /* copy skb_ubuf_info for callback when skb has no error */ 761 if (zerocopy) { 762 skb_shinfo(skb)->destructor_arg = m->msg_control; 763 skb_shinfo(skb)->tx_flags |= SKBTX_DEV_ZEROCOPY; 764 skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; 765 } 766 if (vlan) { 767 skb->dev = vlan->dev; 768 dev_queue_xmit(skb); 769 } else { 770 kfree_skb(skb); 771 } 772 rcu_read_unlock(); 773 774 return total_len; 775 776 err_kfree: 777 kfree_skb(skb); 778 779 err: 780 rcu_read_lock(); 781 vlan = rcu_dereference(q->vlan); 782 if (vlan) 783 this_cpu_inc(vlan->pcpu_stats->tx_dropped); 784 rcu_read_unlock(); 785 786 return err; 787 } 788 789 static ssize_t macvtap_write_iter(struct kiocb *iocb, struct iov_iter *from) 790 { 791 struct file *file = iocb->ki_filp; 792 struct macvtap_queue *q = file->private_data; 793 794 return macvtap_get_user(q, NULL, from, file->f_flags & O_NONBLOCK); 795 } 796 797 /* Put packet to the user space buffer */ 798 static ssize_t macvtap_put_user(struct macvtap_queue *q, 799 const struct sk_buff *skb, 800 struct iov_iter *iter) 801 { 802 int ret; 803 int vnet_hdr_len = 0; 804 int vlan_offset = 0; 805 int total; 806 807 if (q->flags & IFF_VNET_HDR) { 808 struct virtio_net_hdr vnet_hdr; 809 vnet_hdr_len = q->vnet_hdr_sz; 810 if (iov_iter_count(iter) < vnet_hdr_len) 811 return -EINVAL; 812 813 macvtap_skb_to_vnet_hdr(q, skb, &vnet_hdr); 814 815 if (copy_to_iter(&vnet_hdr, sizeof(vnet_hdr), iter) != 816 sizeof(vnet_hdr)) 817 return -EFAULT; 818 819 iov_iter_advance(iter, vnet_hdr_len - sizeof(vnet_hdr)); 820 } 821 total = vnet_hdr_len; 822 total += skb->len; 823 824 if (vlan_tx_tag_present(skb)) { 825 struct { 826 __be16 h_vlan_proto; 827 __be16 h_vlan_TCI; 828 } veth; 829 veth.h_vlan_proto = skb->vlan_proto; 830 veth.h_vlan_TCI = htons(vlan_tx_tag_get(skb)); 831 832 vlan_offset = offsetof(struct vlan_ethhdr, h_vlan_proto); 833 total += VLAN_HLEN; 834 835 ret = skb_copy_datagram_iter(skb, 0, iter, vlan_offset); 836 if (ret || !iov_iter_count(iter)) 837 goto done; 838 839 ret = copy_to_iter(&veth, sizeof(veth), iter); 840 if (ret != sizeof(veth) || !iov_iter_count(iter)) 841 goto done; 842 } 843 844 ret = skb_copy_datagram_iter(skb, vlan_offset, iter, 845 skb->len - vlan_offset); 846 847 done: 848 return ret ? ret : total; 849 } 850 851 static ssize_t macvtap_do_read(struct macvtap_queue *q, 852 struct iov_iter *to, 853 int noblock) 854 { 855 DEFINE_WAIT(wait); 856 struct sk_buff *skb; 857 ssize_t ret = 0; 858 859 if (!iov_iter_count(to)) 860 return 0; 861 862 while (1) { 863 if (!noblock) 864 prepare_to_wait(sk_sleep(&q->sk), &wait, 865 TASK_INTERRUPTIBLE); 866 867 /* Read frames from the queue */ 868 skb = skb_dequeue(&q->sk.sk_receive_queue); 869 if (skb) 870 break; 871 if (noblock) { 872 ret = -EAGAIN; 873 break; 874 } 875 if (signal_pending(current)) { 876 ret = -ERESTARTSYS; 877 break; 878 } 879 /* Nothing to read, let's sleep */ 880 schedule(); 881 } 882 if (skb) { 883 ret = macvtap_put_user(q, skb, to); 884 if (unlikely(ret < 0)) 885 kfree_skb(skb); 886 else 887 consume_skb(skb); 888 } 889 if (!noblock) 890 finish_wait(sk_sleep(&q->sk), &wait); 891 return ret; 892 } 893 894 static ssize_t macvtap_read_iter(struct kiocb *iocb, struct iov_iter *to) 895 { 896 struct file *file = iocb->ki_filp; 897 struct macvtap_queue *q = file->private_data; 898 ssize_t len = iov_iter_count(to), ret; 899 900 ret = macvtap_do_read(q, to, file->f_flags & O_NONBLOCK); 901 ret = min_t(ssize_t, ret, len); 902 if (ret > 0) 903 iocb->ki_pos = ret; 904 return ret; 905 } 906 907 static struct macvlan_dev *macvtap_get_vlan(struct macvtap_queue *q) 908 { 909 struct macvlan_dev *vlan; 910 911 ASSERT_RTNL(); 912 vlan = rtnl_dereference(q->vlan); 913 if (vlan) 914 dev_hold(vlan->dev); 915 916 return vlan; 917 } 918 919 static void macvtap_put_vlan(struct macvlan_dev *vlan) 920 { 921 dev_put(vlan->dev); 922 } 923 924 static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags) 925 { 926 struct macvtap_queue *q = file->private_data; 927 struct macvlan_dev *vlan; 928 int ret; 929 930 vlan = macvtap_get_vlan(q); 931 if (!vlan) 932 return -EINVAL; 933 934 if (flags & IFF_ATTACH_QUEUE) 935 ret = macvtap_enable_queue(vlan->dev, file, q); 936 else if (flags & IFF_DETACH_QUEUE) 937 ret = macvtap_disable_queue(q); 938 else 939 ret = -EINVAL; 940 941 macvtap_put_vlan(vlan); 942 return ret; 943 } 944 945 static int set_offload(struct macvtap_queue *q, unsigned long arg) 946 { 947 struct macvlan_dev *vlan; 948 netdev_features_t features; 949 netdev_features_t feature_mask = 0; 950 951 vlan = rtnl_dereference(q->vlan); 952 if (!vlan) 953 return -ENOLINK; 954 955 features = vlan->dev->features; 956 957 if (arg & TUN_F_CSUM) { 958 feature_mask = NETIF_F_HW_CSUM; 959 960 if (arg & (TUN_F_TSO4 | TUN_F_TSO6)) { 961 if (arg & TUN_F_TSO_ECN) 962 feature_mask |= NETIF_F_TSO_ECN; 963 if (arg & TUN_F_TSO4) 964 feature_mask |= NETIF_F_TSO; 965 if (arg & TUN_F_TSO6) 966 feature_mask |= NETIF_F_TSO6; 967 } 968 } 969 970 /* tun/tap driver inverts the usage for TSO offloads, where 971 * setting the TSO bit means that the userspace wants to 972 * accept TSO frames and turning it off means that user space 973 * does not support TSO. 974 * For macvtap, we have to invert it to mean the same thing. 975 * When user space turns off TSO, we turn off GSO/LRO so that 976 * user-space will not receive TSO frames. 977 */ 978 if (feature_mask & (NETIF_F_TSO | NETIF_F_TSO6)) 979 features |= RX_OFFLOADS; 980 else 981 features &= ~RX_OFFLOADS; 982 983 /* tap_features are the same as features on tun/tap and 984 * reflect user expectations. 985 */ 986 vlan->tap_features = feature_mask; 987 vlan->set_features = features; 988 netdev_update_features(vlan->dev); 989 990 return 0; 991 } 992 993 /* 994 * provide compatibility with generic tun/tap interface 995 */ 996 static long macvtap_ioctl(struct file *file, unsigned int cmd, 997 unsigned long arg) 998 { 999 struct macvtap_queue *q = file->private_data; 1000 struct macvlan_dev *vlan; 1001 void __user *argp = (void __user *)arg; 1002 struct ifreq __user *ifr = argp; 1003 unsigned int __user *up = argp; 1004 unsigned short u; 1005 int __user *sp = argp; 1006 int s; 1007 int ret; 1008 1009 switch (cmd) { 1010 case TUNSETIFF: 1011 /* ignore the name, just look at flags */ 1012 if (get_user(u, &ifr->ifr_flags)) 1013 return -EFAULT; 1014 1015 ret = 0; 1016 if ((u & ~MACVTAP_FEATURES) != (IFF_NO_PI | IFF_TAP)) 1017 ret = -EINVAL; 1018 else 1019 q->flags = (q->flags & ~MACVTAP_FEATURES) | u; 1020 1021 return ret; 1022 1023 case TUNGETIFF: 1024 rtnl_lock(); 1025 vlan = macvtap_get_vlan(q); 1026 if (!vlan) { 1027 rtnl_unlock(); 1028 return -ENOLINK; 1029 } 1030 1031 ret = 0; 1032 u = q->flags; 1033 if (copy_to_user(&ifr->ifr_name, vlan->dev->name, IFNAMSIZ) || 1034 put_user(u, &ifr->ifr_flags)) 1035 ret = -EFAULT; 1036 macvtap_put_vlan(vlan); 1037 rtnl_unlock(); 1038 return ret; 1039 1040 case TUNSETQUEUE: 1041 if (get_user(u, &ifr->ifr_flags)) 1042 return -EFAULT; 1043 rtnl_lock(); 1044 ret = macvtap_ioctl_set_queue(file, u); 1045 rtnl_unlock(); 1046 return ret; 1047 1048 case TUNGETFEATURES: 1049 if (put_user(IFF_TAP | IFF_NO_PI | MACVTAP_FEATURES, up)) 1050 return -EFAULT; 1051 return 0; 1052 1053 case TUNSETSNDBUF: 1054 if (get_user(u, up)) 1055 return -EFAULT; 1056 1057 q->sk.sk_sndbuf = u; 1058 return 0; 1059 1060 case TUNGETVNETHDRSZ: 1061 s = q->vnet_hdr_sz; 1062 if (put_user(s, sp)) 1063 return -EFAULT; 1064 return 0; 1065 1066 case TUNSETVNETHDRSZ: 1067 if (get_user(s, sp)) 1068 return -EFAULT; 1069 if (s < (int)sizeof(struct virtio_net_hdr)) 1070 return -EINVAL; 1071 1072 q->vnet_hdr_sz = s; 1073 return 0; 1074 1075 case TUNGETVNETLE: 1076 s = !!(q->flags & MACVTAP_VNET_LE); 1077 if (put_user(s, sp)) 1078 return -EFAULT; 1079 return 0; 1080 1081 case TUNSETVNETLE: 1082 if (get_user(s, sp)) 1083 return -EFAULT; 1084 if (s) 1085 q->flags |= MACVTAP_VNET_LE; 1086 else 1087 q->flags &= ~MACVTAP_VNET_LE; 1088 return 0; 1089 1090 case TUNSETOFFLOAD: 1091 /* let the user check for future flags */ 1092 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 | 1093 TUN_F_TSO_ECN)) 1094 return -EINVAL; 1095 1096 rtnl_lock(); 1097 ret = set_offload(q, arg); 1098 rtnl_unlock(); 1099 return ret; 1100 1101 default: 1102 return -EINVAL; 1103 } 1104 } 1105 1106 #ifdef CONFIG_COMPAT 1107 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd, 1108 unsigned long arg) 1109 { 1110 return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg)); 1111 } 1112 #endif 1113 1114 static const struct file_operations macvtap_fops = { 1115 .owner = THIS_MODULE, 1116 .open = macvtap_open, 1117 .release = macvtap_release, 1118 .read = new_sync_read, 1119 .write = new_sync_write, 1120 .read_iter = macvtap_read_iter, 1121 .write_iter = macvtap_write_iter, 1122 .poll = macvtap_poll, 1123 .llseek = no_llseek, 1124 .unlocked_ioctl = macvtap_ioctl, 1125 #ifdef CONFIG_COMPAT 1126 .compat_ioctl = macvtap_compat_ioctl, 1127 #endif 1128 }; 1129 1130 static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock, 1131 struct msghdr *m, size_t total_len) 1132 { 1133 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1134 return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT); 1135 } 1136 1137 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock, 1138 struct msghdr *m, size_t total_len, 1139 int flags) 1140 { 1141 struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock); 1142 int ret; 1143 if (flags & ~(MSG_DONTWAIT|MSG_TRUNC)) 1144 return -EINVAL; 1145 ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT); 1146 if (ret > total_len) { 1147 m->msg_flags |= MSG_TRUNC; 1148 ret = flags & MSG_TRUNC ? ret : total_len; 1149 } 1150 return ret; 1151 } 1152 1153 /* Ops structure to mimic raw sockets with tun */ 1154 static const struct proto_ops macvtap_socket_ops = { 1155 .sendmsg = macvtap_sendmsg, 1156 .recvmsg = macvtap_recvmsg, 1157 }; 1158 1159 /* Get an underlying socket object from tun file. Returns error unless file is 1160 * attached to a device. The returned object works like a packet socket, it 1161 * can be used for sock_sendmsg/sock_recvmsg. The caller is responsible for 1162 * holding a reference to the file for as long as the socket is in use. */ 1163 struct socket *macvtap_get_socket(struct file *file) 1164 { 1165 struct macvtap_queue *q; 1166 if (file->f_op != &macvtap_fops) 1167 return ERR_PTR(-EINVAL); 1168 q = file->private_data; 1169 if (!q) 1170 return ERR_PTR(-EBADFD); 1171 return &q->sock; 1172 } 1173 EXPORT_SYMBOL_GPL(macvtap_get_socket); 1174 1175 static int macvtap_device_event(struct notifier_block *unused, 1176 unsigned long event, void *ptr) 1177 { 1178 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 1179 struct macvlan_dev *vlan; 1180 struct device *classdev; 1181 dev_t devt; 1182 int err; 1183 1184 if (dev->rtnl_link_ops != &macvtap_link_ops) 1185 return NOTIFY_DONE; 1186 1187 vlan = netdev_priv(dev); 1188 1189 switch (event) { 1190 case NETDEV_REGISTER: 1191 /* Create the device node here after the network device has 1192 * been registered but before register_netdevice has 1193 * finished running. 1194 */ 1195 err = macvtap_get_minor(vlan); 1196 if (err) 1197 return notifier_from_errno(err); 1198 1199 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1200 classdev = device_create(macvtap_class, &dev->dev, devt, 1201 dev, "tap%d", dev->ifindex); 1202 if (IS_ERR(classdev)) { 1203 macvtap_free_minor(vlan); 1204 return notifier_from_errno(PTR_ERR(classdev)); 1205 } 1206 break; 1207 case NETDEV_UNREGISTER: 1208 devt = MKDEV(MAJOR(macvtap_major), vlan->minor); 1209 device_destroy(macvtap_class, devt); 1210 macvtap_free_minor(vlan); 1211 break; 1212 } 1213 1214 return NOTIFY_DONE; 1215 } 1216 1217 static struct notifier_block macvtap_notifier_block __read_mostly = { 1218 .notifier_call = macvtap_device_event, 1219 }; 1220 1221 static int macvtap_init(void) 1222 { 1223 int err; 1224 1225 err = alloc_chrdev_region(&macvtap_major, 0, 1226 MACVTAP_NUM_DEVS, "macvtap"); 1227 if (err) 1228 goto out1; 1229 1230 cdev_init(&macvtap_cdev, &macvtap_fops); 1231 err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS); 1232 if (err) 1233 goto out2; 1234 1235 macvtap_class = class_create(THIS_MODULE, "macvtap"); 1236 if (IS_ERR(macvtap_class)) { 1237 err = PTR_ERR(macvtap_class); 1238 goto out3; 1239 } 1240 1241 err = register_netdevice_notifier(&macvtap_notifier_block); 1242 if (err) 1243 goto out4; 1244 1245 err = macvlan_link_register(&macvtap_link_ops); 1246 if (err) 1247 goto out5; 1248 1249 return 0; 1250 1251 out5: 1252 unregister_netdevice_notifier(&macvtap_notifier_block); 1253 out4: 1254 class_unregister(macvtap_class); 1255 out3: 1256 cdev_del(&macvtap_cdev); 1257 out2: 1258 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1259 out1: 1260 return err; 1261 } 1262 module_init(macvtap_init); 1263 1264 static void macvtap_exit(void) 1265 { 1266 rtnl_link_unregister(&macvtap_link_ops); 1267 unregister_netdevice_notifier(&macvtap_notifier_block); 1268 class_unregister(macvtap_class); 1269 cdev_del(&macvtap_cdev); 1270 unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS); 1271 } 1272 module_exit(macvtap_exit); 1273 1274 MODULE_ALIAS_RTNL_LINK("macvtap"); 1275 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>"); 1276 MODULE_LICENSE("GPL"); 1277