drivers/net/macvtap.c

   1 #include <linux/etherdevice.h>
   2 #include <linux/if_macvlan.h>
   3 #include <linux/interrupt.h>
   4 #include <linux/nsproxy.h>
   5 #include <linux/compat.h>
   6 #include <linux/if_tun.h>
   7 #include <linux/module.h>
   8 #include <linux/skbuff.h>
   9 #include <linux/cache.h>
  10 #include <linux/sched.h>
  11 #include <linux/types.h>
  12 #include <linux/init.h>
  13 #include <linux/wait.h>
  14 #include <linux/cdev.h>
  15 #include <linux/fs.h>
  16
  17 #include <net/net_namespace.h>
  18 #include <net/rtnetlink.h>
  19 #include <net/sock.h>
  20 #include <linux/virtio_net.h>
  21
  22 /*
  23  * A macvtap queue is the central object of this driver, it connects
  24  * an open character device to a macvlan interface. There can be
  25  * multiple queues on one interface, which map back to queues
  26  * implemented in hardware on the underlying device.
  27  *
  28  * macvtap_proto is used to allocate queues through the sock allocation
  29  * mechanism.
  30  *
  31  * TODO: multiqueue support is currently not implemented, even though
  32  * macvtap is basically prepared for that. We will need to add this
  33  * here as well as in virtio-net and qemu to get line rate on 10gbit
  34  * adapters from a guest.
  35  */
  36 struct macvtap_queue {
  37         struct sock sk;
  38         struct socket sock;
  39         struct macvlan_dev *vlan;
  40         struct file *file;
  41         unsigned int flags;
  42 };
  43
  44 static struct proto macvtap_proto = {
  45         .name = "macvtap",
  46         .owner = THIS_MODULE,
  47         .obj_size = sizeof (struct macvtap_queue),
  48 };
  49
  50 /*
  51  * Minor number matches netdev->ifindex, so need a potentially
  52  * large value. This also makes it possible to split the
  53  * tap functionality out again in the future by offering it
  54  * from other drivers besides macvtap. As long as every device
  55  * only has one tap, the interface numbers assure that the
  56  * device nodes are unique.
  57  */
  58 static unsigned int macvtap_major;
  59 #define MACVTAP_NUM_DEVS 65536
  60 static struct class *macvtap_class;
  61 static struct cdev macvtap_cdev;
  62
  63 static const struct proto_ops macvtap_socket_ops;
  64
  65 /*
  66  * RCU usage:
  67  * The macvtap_queue and the macvlan_dev are loosely coupled, the
  68  * pointers from one to the other can only be read while rcu_read_lock
  69  * or macvtap_lock is held.
  70  *
  71  * Both the file and the macvlan_dev hold a reference on the macvtap_queue
  72  * through sock_hold(&q->sk). When the macvlan_dev goes away first,
  73  * q->vlan becomes inaccessible. When the files gets closed,
  74  * macvtap_get_queue() fails.
  75  *
  76  * There may still be references to the struct sock inside of the
  77  * queue from outbound SKBs, but these never reference back to the
  78  * file or the dev. The data structure is freed through __sk_free
  79  * when both our references and any pending SKBs are gone.
  80  */
  81 static DEFINE_SPINLOCK(macvtap_lock);
  82
  83 /*
  84  * Choose the next free queue, for now there is only one
  85  */
  86 static int macvtap_set_queue(struct net_device *dev, struct file *file,
  87                                 struct macvtap_queue *q)
  88 {
  89         struct macvlan_dev *vlan = netdev_priv(dev);
  90         int err = -EBUSY;
  91
  92         spin_lock(&macvtap_lock);
  93         if (rcu_dereference(vlan->tap))
  94                 goto out;
  95
  96         err = 0;
  97         rcu_assign_pointer(q->vlan, vlan);
  98         rcu_assign_pointer(vlan->tap, q);
  99         sock_hold(&q->sk);
 100
 101         q->file = file;
 102         file->private_data = q;
 103
 104 out:
 105         spin_unlock(&macvtap_lock);
 106         return err;
 107 }
 108
 109 /*
 110  * The file owning the queue got closed, give up both
 111  * the reference that the files holds as well as the
 112  * one from the macvlan_dev if that still exists.
 113  *
 114  * Using the spinlock makes sure that we don't get
 115  * to the queue again after destroying it.
 116  */
 117 static void macvtap_put_queue(struct macvtap_queue *q)
 118 {
 119         struct macvlan_dev *vlan;
 120
 121         spin_lock(&macvtap_lock);
 122         vlan = rcu_dereference(q->vlan);
 123         if (vlan) {
 124                 rcu_assign_pointer(vlan->tap, NULL);
 125                 rcu_assign_pointer(q->vlan, NULL);
 126                 sock_put(&q->sk);
 127         }
 128
 129         spin_unlock(&macvtap_lock);
 130
 131         synchronize_rcu();
 132         sock_put(&q->sk);
 133 }
 134
 135 /*
 136  * Since we only support one queue, just dereference the pointer.
 137  */
 138 static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
 139                                                struct sk_buff *skb)
 140 {
 141         struct macvlan_dev *vlan = netdev_priv(dev);
 142
 143         return rcu_dereference(vlan->tap);
 144 }
 145
 146 /*
 147  * The net_device is going away, give up the reference
 148  * that it holds on the queue (all the queues one day)
 149  * and safely set the pointer from the queues to NULL.
 150  */
 151 static void macvtap_del_queues(struct net_device *dev)
 152 {
 153         struct macvlan_dev *vlan = netdev_priv(dev);
 154         struct macvtap_queue *q;
 155
 156         spin_lock(&macvtap_lock);
 157         q = rcu_dereference(vlan->tap);
 158         if (!q) {
 159                 spin_unlock(&macvtap_lock);
 160                 return;
 161         }
 162
 163         rcu_assign_pointer(vlan->tap, NULL);
 164         rcu_assign_pointer(q->vlan, NULL);
 165         spin_unlock(&macvtap_lock);
 166
 167         synchronize_rcu();
 168         sock_put(&q->sk);
 169 }
 170
 171 /*
 172  * Forward happens for data that gets sent from one macvlan
 173  * endpoint to another one in bridge mode. We just take
 174  * the skb and put it into the receive queue.
 175  */
 176 static int macvtap_forward(struct net_device *dev, struct sk_buff *skb)
 177 {
 178         struct macvtap_queue *q = macvtap_get_queue(dev, skb);
 179         if (!q)
 180                 return -ENOLINK;
 181
 182         skb_queue_tail(&q->sk.sk_receive_queue, skb);
 183         wake_up_interruptible_poll(q->sk.sk_sleep, POLLIN | POLLRDNORM | POLLRDBAND);
 184         return 0;
 185 }
 186
 187 /*
 188  * Receive is for data from the external interface (lowerdev),
 189  * in case of macvtap, we can treat that the same way as
 190  * forward, which macvlan cannot.
 191  */
 192 static int macvtap_receive(struct sk_buff *skb)
 193 {
 194         skb_push(skb, ETH_HLEN);
 195         return macvtap_forward(skb->dev, skb);
 196 }
 197
 198 static int macvtap_newlink(struct net *src_net,
 199                            struct net_device *dev,
 200                            struct nlattr *tb[],
 201                            struct nlattr *data[])
 202 {
 203         struct device *classdev;
 204         dev_t devt;
 205         int err;
 206
 207         err = macvlan_common_newlink(src_net, dev, tb, data,
 208                                      macvtap_receive, macvtap_forward);
 209         if (err)
 210                 goto out;
 211
 212         devt = MKDEV(MAJOR(macvtap_major), dev->ifindex);
 213
 214         classdev = device_create(macvtap_class, &dev->dev, devt,
 215                                  dev, "tap%d", dev->ifindex);
 216         if (IS_ERR(classdev)) {
 217                 err = PTR_ERR(classdev);
 218                 macvtap_del_queues(dev);
 219         }
 220
 221 out:
 222         return err;
 223 }
 224
 225 static void macvtap_dellink(struct net_device *dev,
 226                             struct list_head *head)
 227 {
 228         device_destroy(macvtap_class,
 229                        MKDEV(MAJOR(macvtap_major), dev->ifindex));
 230
 231         macvtap_del_queues(dev);
 232         macvlan_dellink(dev, head);
 233 }
 234
 235 static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
 236         .kind           = "macvtap",
 237         .newlink        = macvtap_newlink,
 238         .dellink        = macvtap_dellink,
 239 };
 240
 241
 242 static void macvtap_sock_write_space(struct sock *sk)
 243 {
 244         if (!sock_writeable(sk) ||
 245             !test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 246                 return;
 247
 248         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 249                 wake_up_interruptible_poll(sk->sk_sleep, POLLOUT | POLLWRNORM | POLLWRBAND);
 250 }
 251
 252 static int macvtap_open(struct inode *inode, struct file *file)
 253 {
 254         struct net *net = current->nsproxy->net_ns;
 255         struct net_device *dev = dev_get_by_index(net, iminor(inode));
 256         struct macvtap_queue *q;
 257         int err;
 258
 259         err = -ENODEV;
 260         if (!dev)
 261                 goto out;
 262
 263         /* check if this is a macvtap device */
 264         err = -EINVAL;
 265         if (dev->rtnl_link_ops != &macvtap_link_ops)
 266                 goto out;
 267
 268         err = -ENOMEM;
 269         q = (struct macvtap_queue *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
 270                                              &macvtap_proto);
 271         if (!q)
 272                 goto out;
 273
 274         init_waitqueue_head(&q->sock.wait);
 275         q->sock.type = SOCK_RAW;
 276         q->sock.state = SS_CONNECTED;
 277         q->sock.file = file;
 278         q->sock.ops = &macvtap_socket_ops;
 279         sock_init_data(&q->sock, &q->sk);
 280         q->sk.sk_write_space = macvtap_sock_write_space;
 281         q->flags = IFF_VNET_HDR | IFF_NO_PI | IFF_TAP;
 282
 283         err = macvtap_set_queue(dev, file, q);
 284         if (err)
 285                 sock_put(&q->sk);
 286
 287 out:
 288         if (dev)
 289                 dev_put(dev);
 290
 291         return err;
 292 }
 293
 294 static int macvtap_release(struct inode *inode, struct file *file)
 295 {
 296         struct macvtap_queue *q = file->private_data;
 297         macvtap_put_queue(q);
 298         return 0;
 299 }
 300
 301 static unsigned int macvtap_poll(struct file *file, poll_table * wait)
 302 {
 303         struct macvtap_queue *q = file->private_data;
 304         unsigned int mask = POLLERR;
 305
 306         if (!q)
 307                 goto out;
 308
 309         mask = 0;
 310         poll_wait(file, &q->sock.wait, wait);
 311
 312         if (!skb_queue_empty(&q->sk.sk_receive_queue))
 313                 mask |= POLLIN | POLLRDNORM;
 314
 315         if (sock_writeable(&q->sk) ||
 316             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &q->sock.flags) &&
 317              sock_writeable(&q->sk)))
 318                 mask |= POLLOUT | POLLWRNORM;
 319
 320 out:
 321         return mask;
 322 }
 323
 324 static inline struct sk_buff *macvtap_alloc_skb(struct sock *sk, size_t prepad,
 325                                                 size_t len, size_t linear,
 326                                                 int noblock, int *err)
 327 {
 328         struct sk_buff *skb;
 329
 330         /* Under a page?  Don't bother with paged skb. */
 331         if (prepad + len < PAGE_SIZE || !linear)
 332                 linear = len;
 333
 334         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 335                                    err);
 336         if (!skb)
 337                 return NULL;
 338
 339         skb_reserve(skb, prepad);
 340         skb_put(skb, linear);
 341         skb->data_len = len - linear;
 342         skb->len += len - linear;
 343
 344         return skb;
 345 }
 346
 347 /*
 348  * macvtap_skb_from_vnet_hdr and macvtap_skb_to_vnet_hdr should
 349  * be shared with the tun/tap driver.
 350  */
 351 static int macvtap_skb_from_vnet_hdr(struct sk_buff *skb,
 352                                      struct virtio_net_hdr *vnet_hdr)
 353 {
 354         unsigned short gso_type = 0;
 355         if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 356                 switch (vnet_hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 357                 case VIRTIO_NET_HDR_GSO_TCPV4:
 358                         gso_type = SKB_GSO_TCPV4;
 359                         break;
 360                 case VIRTIO_NET_HDR_GSO_TCPV6:
 361                         gso_type = SKB_GSO_TCPV6;
 362                         break;
 363                 case VIRTIO_NET_HDR_GSO_UDP:
 364                         gso_type = SKB_GSO_UDP;
 365                         break;
 366                 default:
 367                         return -EINVAL;
 368                 }
 369
 370                 if (vnet_hdr->gso_type & VIRTIO_NET_HDR_GSO_ECN)
 371                         gso_type |= SKB_GSO_TCP_ECN;
 372
 373                 if (vnet_hdr->gso_size == 0)
 374                         return -EINVAL;
 375         }
 376
 377         if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 378                 if (!skb_partial_csum_set(skb, vnet_hdr->csum_start,
 379                                           vnet_hdr->csum_offset))
 380                         return -EINVAL;
 381         }
 382
 383         if (vnet_hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 384                 skb_shinfo(skb)->gso_size = vnet_hdr->gso_size;
 385                 skb_shinfo(skb)->gso_type = gso_type;
 386
 387                 /* Header must be checked, and gso_segs computed. */
 388                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 389                 skb_shinfo(skb)->gso_segs = 0;
 390         }
 391         return 0;
 392 }
 393
 394 static int macvtap_skb_to_vnet_hdr(const struct sk_buff *skb,
 395                                    struct virtio_net_hdr *vnet_hdr)
 396 {
 397         memset(vnet_hdr, 0, sizeof(*vnet_hdr));
 398
 399         if (skb_is_gso(skb)) {
 400                 struct skb_shared_info *sinfo = skb_shinfo(skb);
 401
 402                 /* This is a hint as to how much should be linear. */
 403                 vnet_hdr->hdr_len = skb_headlen(skb);
 404                 vnet_hdr->gso_size = sinfo->gso_size;
 405                 if (sinfo->gso_type & SKB_GSO_TCPV4)
 406                         vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 407                 else if (sinfo->gso_type & SKB_GSO_TCPV6)
 408                         vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 409                 else if (sinfo->gso_type & SKB_GSO_UDP)
 410                         vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_UDP;
 411                 else
 412                         BUG();
 413                 if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 414                         vnet_hdr->gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 415         } else
 416                 vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_NONE;
 417
 418         if (skb->ip_summed == CHECKSUM_PARTIAL) {
 419                 vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 420                 vnet_hdr->csum_start = skb->csum_start -
 421                                         skb_headroom(skb);
 422                 vnet_hdr->csum_offset = skb->csum_offset;
 423         } /* else everything is zero */
 424
 425         return 0;
 426 }
 427
 428
 429 /* Get packet from user space buffer */
 430 static ssize_t macvtap_get_user(struct macvtap_queue *q,
 431                                 const struct iovec *iv, size_t count,
 432                                 int noblock)
 433 {
 434         struct sk_buff *skb;
 435         struct macvlan_dev *vlan;
 436         size_t len = count;
 437         int err;
 438         struct virtio_net_hdr vnet_hdr = { 0 };
 439         int vnet_hdr_len = 0;
 440
 441         if (q->flags & IFF_VNET_HDR) {
 442                 vnet_hdr_len = sizeof(vnet_hdr);
 443
 444                 err = -EINVAL;
 445                 if ((len -= vnet_hdr_len) < 0)
 446                         goto err;
 447
 448                 err = memcpy_fromiovecend((void *)&vnet_hdr, iv, 0,
 449                                            vnet_hdr_len);
 450                 if (err < 0)
 451                         goto err;
 452                 if ((vnet_hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 453                      vnet_hdr.csum_start + vnet_hdr.csum_offset + 2 >
 454                                                         vnet_hdr.hdr_len)
 455                         vnet_hdr.hdr_len = vnet_hdr.csum_start +
 456                                                 vnet_hdr.csum_offset + 2;
 457                 err = -EINVAL;
 458                 if (vnet_hdr.hdr_len > len)
 459                         goto err;
 460         }
 461
 462         err = -EINVAL;
 463         if (unlikely(len < ETH_HLEN))
 464                 goto err;
 465
 466         skb = macvtap_alloc_skb(&q->sk, NET_IP_ALIGN, len, vnet_hdr.hdr_len,
 467                                 noblock, &err);
 468         if (!skb)
 469                 goto err;
 470
 471         err = skb_copy_datagram_from_iovec(skb, 0, iv, vnet_hdr_len, len);
 472         if (err)
 473                 goto err_kfree;
 474
 475         skb_set_network_header(skb, ETH_HLEN);
 476         skb_reset_mac_header(skb);
 477         skb->protocol = eth_hdr(skb)->h_proto;
 478
 479         if (vnet_hdr_len) {
 480                 err = macvtap_skb_from_vnet_hdr(skb, &vnet_hdr);
 481                 if (err)
 482                         goto err_kfree;
 483         }
 484
 485         rcu_read_lock_bh();
 486         vlan = rcu_dereference(q->vlan);
 487         if (vlan)
 488                 macvlan_start_xmit(skb, vlan->dev);
 489         else
 490                 kfree_skb(skb);
 491         rcu_read_unlock_bh();
 492
 493         return count;
 494
 495 err_kfree:
 496         kfree_skb(skb);
 497
 498 err:
 499         rcu_read_lock_bh();
 500         vlan = rcu_dereference(q->vlan);
 501         if (vlan)
 502                 netdev_get_tx_queue(vlan->dev, 0)->tx_dropped++;
 503         rcu_read_unlock_bh();
 504
 505         return err;
 506 }
 507
 508 static ssize_t macvtap_aio_write(struct kiocb *iocb, const struct iovec *iv,
 509                                  unsigned long count, loff_t pos)
 510 {
 511         struct file *file = iocb->ki_filp;
 512         ssize_t result = -ENOLINK;
 513         struct macvtap_queue *q = file->private_data;
 514
 515         result = macvtap_get_user(q, iv, iov_length(iv, count),
 516                               file->f_flags & O_NONBLOCK);
 517         return result;
 518 }
 519
 520 /* Put packet to the user space buffer */
 521 static ssize_t macvtap_put_user(struct macvtap_queue *q,
 522                                 const struct sk_buff *skb,
 523                                 const struct iovec *iv, int len)
 524 {
 525         struct macvlan_dev *vlan;
 526         int ret;
 527         int vnet_hdr_len = 0;
 528
 529         if (q->flags & IFF_VNET_HDR) {
 530                 struct virtio_net_hdr vnet_hdr;
 531                 vnet_hdr_len = sizeof (vnet_hdr);
 532                 if ((len -= vnet_hdr_len) < 0)
 533                         return -EINVAL;
 534
 535                 ret = macvtap_skb_to_vnet_hdr(skb, &vnet_hdr);
 536                 if (ret)
 537                         return ret;
 538
 539                 if (memcpy_toiovecend(iv, (void *)&vnet_hdr, 0, vnet_hdr_len))
 540                         return -EFAULT;
 541         }
 542
 543         len = min_t(int, skb->len, len);
 544
 545         ret = skb_copy_datagram_const_iovec(skb, 0, iv, vnet_hdr_len, len);
 546
 547         rcu_read_lock_bh();
 548         vlan = rcu_dereference(q->vlan);
 549         if (vlan)
 550                 macvlan_count_rx(vlan, len, ret == 0, 0);
 551         rcu_read_unlock_bh();
 552
 553         return ret ? ret : (len + vnet_hdr_len);
 554 }
 555
 556 static ssize_t macvtap_do_read(struct macvtap_queue *q, struct kiocb *iocb,
 557                                const struct iovec *iv, unsigned long len,
 558                                int noblock)
 559 {
 560         DECLARE_WAITQUEUE(wait, current);
 561         struct sk_buff *skb;
 562         ssize_t ret = 0;
 563
 564         add_wait_queue(q->sk.sk_sleep, &wait);
 565         while (len) {
 566                 current->state = TASK_INTERRUPTIBLE;
 567
 568                 /* Read frames from the queue */
 569                 skb = skb_dequeue(&q->sk.sk_receive_queue);
 570                 if (!skb) {
 571                         if (noblock) {
 572                                 ret = -EAGAIN;
 573                                 break;
 574                         }
 575                         if (signal_pending(current)) {
 576                                 ret = -ERESTARTSYS;
 577                                 break;
 578                         }
 579                         /* Nothing to read, let's sleep */
 580                         schedule();
 581                         continue;
 582                 }
 583                 ret = macvtap_put_user(q, skb, iv, len);
 584                 kfree_skb(skb);
 585                 break;
 586         }
 587
 588         current->state = TASK_RUNNING;
 589         remove_wait_queue(q->sk.sk_sleep, &wait);
 590         return ret;
 591 }
 592
 593 static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
 594                                 unsigned long count, loff_t pos)
 595 {
 596         struct file *file = iocb->ki_filp;
 597         struct macvtap_queue *q = file->private_data;
 598         ssize_t len, ret = 0;
 599
 600         len = iov_length(iv, count);
 601         if (len < 0) {
 602                 ret = -EINVAL;
 603                 goto out;
 604         }
 605
 606         ret = macvtap_do_read(q, iocb, iv, len, file->f_flags & O_NONBLOCK);
 607         ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
 608 out:
 609         return ret;
 610 }
 611
 612 /*
 613  * provide compatibility with generic tun/tap interface
 614  */
 615 static long macvtap_ioctl(struct file *file, unsigned int cmd,
 616                           unsigned long arg)
 617 {
 618         struct macvtap_queue *q = file->private_data;
 619         struct macvlan_dev *vlan;
 620         void __user *argp = (void __user *)arg;
 621         struct ifreq __user *ifr = argp;
 622         unsigned int __user *up = argp;
 623         unsigned int u;
 624         int ret;
 625
 626         switch (cmd) {
 627         case TUNSETIFF:
 628                 /* ignore the name, just look at flags */
 629                 if (get_user(u, &ifr->ifr_flags))
 630                         return -EFAULT;
 631
 632                 ret = 0;
 633                 if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
 634                         ret = -EINVAL;
 635                 else
 636                         q->flags = u;
 637
 638                 return ret;
 639
 640         case TUNGETIFF:
 641                 rcu_read_lock_bh();
 642                 vlan = rcu_dereference(q->vlan);
 643                 if (vlan)
 644                         dev_hold(vlan->dev);
 645                 rcu_read_unlock_bh();
 646
 647                 if (!vlan)
 648                         return -ENOLINK;
 649
 650                 ret = 0;
 651                 if (copy_to_user(&ifr->ifr_name, q->vlan->dev->name, IFNAMSIZ) ||
 652                     put_user(q->flags, &ifr->ifr_flags))
 653                         ret = -EFAULT;
 654                 dev_put(vlan->dev);
 655                 return ret;
 656
 657         case TUNGETFEATURES:
 658                 if (put_user(IFF_TAP | IFF_NO_PI | IFF_VNET_HDR, up))
 659                         return -EFAULT;
 660                 return 0;
 661
 662         case TUNSETSNDBUF:
 663                 if (get_user(u, up))
 664                         return -EFAULT;
 665
 666                 q->sk.sk_sndbuf = u;
 667                 return 0;
 668
 669         case TUNSETOFFLOAD:
 670                 /* let the user check for future flags */
 671                 if (arg & ~(TUN_F_CSUM | TUN_F_TSO4 | TUN_F_TSO6 |
 672                             TUN_F_TSO_ECN | TUN_F_UFO))
 673                         return -EINVAL;
 674
 675                 /* TODO: only accept frames with the features that
 676                          got enabled for forwarded frames */
 677                 if (!(q->flags & IFF_VNET_HDR))
 678                         return  -EINVAL;
 679                 return 0;
 680
 681         default:
 682                 return -EINVAL;
 683         }
 684 }
 685
 686 #ifdef CONFIG_COMPAT
 687 static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
 688                                  unsigned long arg)
 689 {
 690         return macvtap_ioctl(file, cmd, (unsigned long)compat_ptr(arg));
 691 }
 692 #endif
 693
 694 static const struct file_operations macvtap_fops = {
 695         .owner          = THIS_MODULE,
 696         .open           = macvtap_open,
 697         .release        = macvtap_release,
 698         .aio_read       = macvtap_aio_read,
 699         .aio_write      = macvtap_aio_write,
 700         .poll           = macvtap_poll,
 701         .llseek         = no_llseek,
 702         .unlocked_ioctl = macvtap_ioctl,
 703 #ifdef CONFIG_COMPAT
 704         .compat_ioctl   = macvtap_compat_ioctl,
 705 #endif
 706 };
 707
 708 static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
 709                            struct msghdr *m, size_t total_len)
 710 {
 711         struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
 712         return macvtap_get_user(q, m->msg_iov, total_len,
 713                             m->msg_flags & MSG_DONTWAIT);
 714 }
 715
 716 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
 717                            struct msghdr *m, size_t total_len,
 718                            int flags)
 719 {
 720         struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
 721         int ret;
 722         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
 723                 return -EINVAL;
 724         ret = macvtap_do_read(q, iocb, m->msg_iov, total_len,
 725                           flags & MSG_DONTWAIT);
 726         if (ret > total_len) {
 727                 m->msg_flags |= MSG_TRUNC;
 728                 ret = flags & MSG_TRUNC ? ret : total_len;
 729         }
 730         return ret;
 731 }
 732
 733 /* Ops structure to mimic raw sockets with tun */
 734 static const struct proto_ops macvtap_socket_ops = {
 735         .sendmsg = macvtap_sendmsg,
 736         .recvmsg = macvtap_recvmsg,
 737 };
 738
 739 /* Get an underlying socket object from tun file.  Returns error unless file is
 740  * attached to a device.  The returned object works like a packet socket, it
 741  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
 742  * holding a reference to the file for as long as the socket is in use. */
 743 struct socket *macvtap_get_socket(struct file *file)
 744 {
 745         struct macvtap_queue *q;
 746         if (file->f_op != &macvtap_fops)
 747                 return ERR_PTR(-EINVAL);
 748         q = file->private_data;
 749         if (!q)
 750                 return ERR_PTR(-EBADFD);
 751         return &q->sock;
 752 }
 753 EXPORT_SYMBOL_GPL(macvtap_get_socket);
 754
 755 static int macvtap_init(void)
 756 {
 757         int err;
 758
 759         err = alloc_chrdev_region(&macvtap_major, 0,
 760                                 MACVTAP_NUM_DEVS, "macvtap");
 761         if (err)
 762                 goto out1;
 763
 764         cdev_init(&macvtap_cdev, &macvtap_fops);
 765         err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
 766         if (err)
 767                 goto out2;
 768
 769         macvtap_class = class_create(THIS_MODULE, "macvtap");
 770         if (IS_ERR(macvtap_class)) {
 771                 err = PTR_ERR(macvtap_class);
 772                 goto out3;
 773         }
 774
 775         err = macvlan_link_register(&macvtap_link_ops);
 776         if (err)
 777                 goto out4;
 778
 779         return 0;
 780
 781 out4:
 782         class_unregister(macvtap_class);
 783 out3:
 784         cdev_del(&macvtap_cdev);
 785 out2:
 786         unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
 787 out1:
 788         return err;
 789 }
 790 module_init(macvtap_init);
 791
 792 static void macvtap_exit(void)
 793 {
 794         rtnl_link_unregister(&macvtap_link_ops);
 795         class_unregister(macvtap_class);
 796         cdev_del(&macvtap_cdev);
 797         unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
 798 }
 799 module_exit(macvtap_exit);
 800
 801 MODULE_ALIAS_RTNL_LINK("macvtap");
 802 MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
 803 MODULE_LICENSE("GPL");