SAFE public projects git trees. - safe/jmp/linux-2.6/blob - drivers/net/tun.c

   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use random_ether_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define DRV_NAME        "tun"
  38 #define DRV_VERSION     "1.6"
  39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  40 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  41
  42 #include <linux/module.h>
  43 #include <linux/errno.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/slab.h>
  47 #include <linux/smp_lock.h>
  48 #include <linux/poll.h>
  49 #include <linux/fcntl.h>
  50 #include <linux/init.h>
  51 #include <linux/skbuff.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/etherdevice.h>
  54 #include <linux/miscdevice.h>
  55 #include <linux/ethtool.h>
  56 #include <linux/rtnetlink.h>
  57 #include <linux/if.h>
  58 #include <linux/if_arp.h>
  59 #include <linux/if_ether.h>
  60 #include <linux/if_tun.h>
  61 #include <linux/crc32.h>
  62 #include <linux/nsproxy.h>
  63 #include <linux/virtio_net.h>
  64 #include <net/net_namespace.h>
  65 #include <net/netns/generic.h>
  66 #include <net/rtnetlink.h>
  67 #include <net/sock.h>
  68
  69 #include <asm/system.h>
  70 #include <asm/uaccess.h>
  71
  72 /* Uncomment to enable debugging */
  73 /* #define TUN_DEBUG 1 */
  74
  75 #ifdef TUN_DEBUG
  76 static int debug;
  77
  78 #define DBG  if(tun->debug)printk
  79 #define DBG1 if(debug==2)printk
  80 #else
  81 #define DBG( a... )
  82 #define DBG1( a... )
  83 #endif
  84
  85 #define FLT_EXACT_COUNT 8
  86 struct tap_filter {
  87         unsigned int    count;    /* Number of addrs. Zero means disabled */
  88         u32             mask[2];  /* Mask of the hashed addrs */
  89         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
  90 };
  91
  92 struct tun_file {
  93         atomic_t count;
  94         struct tun_struct *tun;
  95         struct net *net;
  96         wait_queue_head_t       read_wait;
  97 };
  98
  99 struct tun_sock;
 100
 101 struct tun_struct {
 102         struct tun_file         *tfile;
 103         unsigned int            flags;
 104         uid_t                   owner;
 105         gid_t                   group;
 106
 107         struct sk_buff_head     readq;
 108
 109         struct net_device       *dev;
 110         struct fasync_struct    *fasync;
 111
 112         struct tap_filter       txflt;
 113         struct sock             *sk;
 114         struct socket           socket;
 115
 116 #ifdef TUN_DEBUG
 117         int debug;
 118 #endif
 119 };
 120
 121 struct tun_sock {
 122         struct sock             sk;
 123         struct tun_struct       *tun;
 124 };
 125
 126 static inline struct tun_sock *tun_sk(struct sock *sk)
 127 {
 128         return container_of(sk, struct tun_sock, sk);
 129 }
 130
 131 static int tun_attach(struct tun_struct *tun, struct file *file)
 132 {
 133         struct tun_file *tfile = file->private_data;
 134         const struct cred *cred = current_cred();
 135         int err;
 136
 137         ASSERT_RTNL();
 138
 139         /* Check permissions */
 140         if (((tun->owner != -1 && cred->euid != tun->owner) ||
 141              (tun->group != -1 && !in_egroup_p(tun->group))) &&
 142                 !capable(CAP_NET_ADMIN))
 143                 return -EPERM;
 144
 145         netif_tx_lock_bh(tun->dev);
 146
 147         err = -EINVAL;
 148         if (tfile->tun)
 149                 goto out;
 150
 151         err = -EBUSY;
 152         if (tun->tfile)
 153                 goto out;
 154
 155         err = 0;
 156         tfile->tun = tun;
 157         tun->tfile = tfile;
 158         dev_hold(tun->dev);
 159         sock_hold(tun->sk);
 160         atomic_inc(&tfile->count);
 161
 162 out:
 163         netif_tx_unlock_bh(tun->dev);
 164         return err;
 165 }
 166
 167 static void __tun_detach(struct tun_struct *tun)
 168 {
 169         /* Detach from net device */
 170         netif_tx_lock_bh(tun->dev);
 171         tun->tfile = NULL;
 172         netif_tx_unlock_bh(tun->dev);
 173
 174         /* Drop read queue */
 175         skb_queue_purge(&tun->readq);
 176
 177         /* Drop the extra count on the net device */
 178         dev_put(tun->dev);
 179 }
 180
 181 static void tun_detach(struct tun_struct *tun)
 182 {
 183         rtnl_lock();
 184         __tun_detach(tun);
 185         rtnl_unlock();
 186 }
 187
 188 static struct tun_struct *__tun_get(struct tun_file *tfile)
 189 {
 190         struct tun_struct *tun = NULL;
 191
 192         if (atomic_inc_not_zero(&tfile->count))
 193                 tun = tfile->tun;
 194
 195         return tun;
 196 }
 197
 198 static struct tun_struct *tun_get(struct file *file)
 199 {
 200         return __tun_get(file->private_data);
 201 }
 202
 203 static void tun_put(struct tun_struct *tun)
 204 {
 205         struct tun_file *tfile = tun->tfile;
 206
 207         if (atomic_dec_and_test(&tfile->count))
 208                 tun_detach(tfile->tun);
 209 }
 210
 211 /* TAP filterting */
 212 static void addr_hash_set(u32 *mask, const u8 *addr)
 213 {
 214         int n = ether_crc(ETH_ALEN, addr) >> 26;
 215         mask[n >> 5] |= (1 << (n & 31));
 216 }
 217
 218 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 219 {
 220         int n = ether_crc(ETH_ALEN, addr) >> 26;
 221         return mask[n >> 5] & (1 << (n & 31));
 222 }
 223
 224 static int update_filter(struct tap_filter *filter, void __user *arg)
 225 {
 226         struct { u8 u[ETH_ALEN]; } *addr;
 227         struct tun_filter uf;
 228         int err, alen, n, nexact;
 229
 230         if (copy_from_user(&uf, arg, sizeof(uf)))
 231                 return -EFAULT;
 232
 233         if (!uf.count) {
 234                 /* Disabled */
 235                 filter->count = 0;
 236                 return 0;
 237         }
 238
 239         alen = ETH_ALEN * uf.count;
 240         addr = kmalloc(alen, GFP_KERNEL);
 241         if (!addr)
 242                 return -ENOMEM;
 243
 244         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 245                 err = -EFAULT;
 246                 goto done;
 247         }
 248
 249         /* The filter is updated without holding any locks. Which is
 250          * perfectly safe. We disable it first and in the worst
 251          * case we'll accept a few undesired packets. */
 252         filter->count = 0;
 253         wmb();
 254
 255         /* Use first set of addresses as an exact filter */
 256         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 257                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 258
 259         nexact = n;
 260
 261         /* Remaining multicast addresses are hashed,
 262          * unicast will leave the filter disabled. */
 263         memset(filter->mask, 0, sizeof(filter->mask));
 264         for (; n < uf.count; n++) {
 265                 if (!is_multicast_ether_addr(addr[n].u)) {
 266                         err = 0; /* no filter */
 267                         goto done;
 268                 }
 269                 addr_hash_set(filter->mask, addr[n].u);
 270         }
 271
 272         /* For ALLMULTI just set the mask to all ones.
 273          * This overrides the mask populated above. */
 274         if ((uf.flags & TUN_FLT_ALLMULTI))
 275                 memset(filter->mask, ~0, sizeof(filter->mask));
 276
 277         /* Now enable the filter */
 278         wmb();
 279         filter->count = nexact;
 280
 281         /* Return the number of exact filters */
 282         err = nexact;
 283
 284 done:
 285         kfree(addr);
 286         return err;
 287 }
 288
 289 /* Returns: 0 - drop, !=0 - accept */
 290 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 291 {
 292         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 293          * at this point. */
 294         struct ethhdr *eh = (struct ethhdr *) skb->data;
 295         int i;
 296
 297         /* Exact match */
 298         for (i = 0; i < filter->count; i++)
 299                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
 300                         return 1;
 301
 302         /* Inexact match (multicast only) */
 303         if (is_multicast_ether_addr(eh->h_dest))
 304                 return addr_hash_test(filter->mask, eh->h_dest);
 305
 306         return 0;
 307 }
 308
 309 /*
 310  * Checks whether the packet is accepted or not.
 311  * Returns: 0 - drop, !=0 - accept
 312  */
 313 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 314 {
 315         if (!filter->count)
 316                 return 1;
 317
 318         return run_filter(filter, skb);
 319 }
 320
 321 /* Network device part of the driver */
 322
 323 static const struct ethtool_ops tun_ethtool_ops;
 324
 325 /* Net device detach from fd. */
 326 static void tun_net_uninit(struct net_device *dev)
 327 {
 328         struct tun_struct *tun = netdev_priv(dev);
 329         struct tun_file *tfile = tun->tfile;
 330
 331         /* Inform the methods they need to stop using the dev.
 332          */
 333         if (tfile) {
 334                 wake_up_all(&tfile->read_wait);
 335                 if (atomic_dec_and_test(&tfile->count))
 336                         __tun_detach(tun);
 337         }
 338 }
 339
 340 static void tun_free_netdev(struct net_device *dev)
 341 {
 342         struct tun_struct *tun = netdev_priv(dev);
 343
 344         sock_put(tun->sk);
 345 }
 346
 347 /* Net device open. */
 348 static int tun_net_open(struct net_device *dev)
 349 {
 350         netif_start_queue(dev);
 351         return 0;
 352 }
 353
 354 /* Net device close. */
 355 static int tun_net_close(struct net_device *dev)
 356 {
 357         netif_stop_queue(dev);
 358         return 0;
 359 }
 360
 361 /* Net device start xmit */
 362 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 363 {
 364         struct tun_struct *tun = netdev_priv(dev);
 365
 366         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 367
 368         /* Drop packet if interface is not attached */
 369         if (!tun->tfile)
 370                 goto drop;
 371
 372         /* Drop if the filter does not like it.
 373          * This is a noop if the filter is disabled.
 374          * Filter can be enabled only for the TAP devices. */
 375         if (!check_filter(&tun->txflt, skb))
 376                 goto drop;
 377
 378         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
 379                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 380                         /* Normal queueing mode. */
 381                         /* Packet scheduler handles dropping of further packets. */
 382                         netif_stop_queue(dev);
 383
 384                         /* We won't see all dropped packets individually, so overrun
 385                          * error is more appropriate. */
 386                         dev->stats.tx_fifo_errors++;
 387                 } else {
 388                         /* Single queue mode.
 389                          * Driver handles dropping of all packets itself. */
 390                         goto drop;
 391                 }
 392         }
 393
 394         /* Enqueue packet */
 395         skb_queue_tail(&tun->readq, skb);
 396         dev->trans_start = jiffies;
 397
 398         /* Notify and wake up reader process */
 399         if (tun->flags & TUN_FASYNC)
 400                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 401         wake_up_interruptible(&tun->tfile->read_wait);
 402         return 0;
 403
 404 drop:
 405         dev->stats.tx_dropped++;
 406         kfree_skb(skb);
 407         return 0;
 408 }
 409
 410 static void tun_net_mclist(struct net_device *dev)
 411 {
 412         /*
 413          * This callback is supposed to deal with mc filter in
 414          * _rx_ path and has nothing to do with the _tx_ path.
 415          * In rx path we always accept everything userspace gives us.
 416          */
 417         return;
 418 }
 419
 420 #define MIN_MTU 68
 421 #define MAX_MTU 65535
 422
 423 static int
 424 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 425 {
 426         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 427                 return -EINVAL;
 428         dev->mtu = new_mtu;
 429         return 0;
 430 }
 431
 432 static const struct net_device_ops tun_netdev_ops = {
 433         .ndo_uninit             = tun_net_uninit,
 434         .ndo_open               = tun_net_open,
 435         .ndo_stop               = tun_net_close,
 436         .ndo_start_xmit         = tun_net_xmit,
 437         .ndo_change_mtu         = tun_net_change_mtu,
 438 };
 439
 440 static const struct net_device_ops tap_netdev_ops = {
 441         .ndo_uninit             = tun_net_uninit,
 442         .ndo_open               = tun_net_open,
 443         .ndo_stop               = tun_net_close,
 444         .ndo_start_xmit         = tun_net_xmit,
 445         .ndo_change_mtu         = tun_net_change_mtu,
 446         .ndo_set_multicast_list = tun_net_mclist,
 447         .ndo_set_mac_address    = eth_mac_addr,
 448         .ndo_validate_addr      = eth_validate_addr,
 449 };
 450
 451 /* Initialize net device. */
 452 static void tun_net_init(struct net_device *dev)
 453 {
 454         struct tun_struct *tun = netdev_priv(dev);
 455
 456         switch (tun->flags & TUN_TYPE_MASK) {
 457         case TUN_TUN_DEV:
 458                 dev->netdev_ops = &tun_netdev_ops;
 459
 460                 /* Point-to-Point TUN Device */
 461                 dev->hard_header_len = 0;
 462                 dev->addr_len = 0;
 463                 dev->mtu = 1500;
 464
 465                 /* Zero header length */
 466                 dev->type = ARPHRD_NONE;
 467                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 468                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 469                 break;
 470
 471         case TUN_TAP_DEV:
 472                 dev->netdev_ops = &tap_netdev_ops;
 473                 /* Ethernet TAP Device */
 474                 ether_setup(dev);
 475
 476                 random_ether_addr(dev->dev_addr);
 477
 478                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 479                 break;
 480         }
 481 }
 482
 483 /* Character device part */
 484
 485 /* Poll */
 486 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 487 {
 488         struct tun_file *tfile = file->private_data;
 489         struct tun_struct *tun = __tun_get(tfile);
 490         struct sock *sk = tun->sk;
 491         unsigned int mask = 0;
 492
 493         if (!tun)
 494                 return POLLERR;
 495
 496         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 497
 498         poll_wait(file, &tfile->read_wait, wait);
 499
 500         if (!skb_queue_empty(&tun->readq))
 501                 mask |= POLLIN | POLLRDNORM;
 502
 503         if (sock_writeable(sk) ||
 504             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 505              sock_writeable(sk)))
 506                 mask |= POLLOUT | POLLWRNORM;
 507
 508         if (tun->dev->reg_state != NETREG_REGISTERED)
 509                 mask = POLLERR;
 510
 511         tun_put(tun);
 512         return mask;
 513 }
 514
 515 /* prepad is the amount to reserve at front.  len is length after that.
 516  * linear is a hint as to how much to copy (usually headers). */
 517 static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 518                                             size_t prepad, size_t len,
 519                                             size_t linear, int noblock)
 520 {
 521         struct sock *sk = tun->sk;
 522         struct sk_buff *skb;
 523         int err;
 524
 525         /* Under a page?  Don't bother with paged skb. */
 526         if (prepad + len < PAGE_SIZE || !linear)
 527                 linear = len;
 528
 529         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 530                                    &err);
 531         if (!skb)
 532                 return ERR_PTR(err);
 533
 534         skb_reserve(skb, prepad);
 535         skb_put(skb, linear);
 536         skb->data_len = len - linear;
 537         skb->len += len - linear;
 538
 539         return skb;
 540 }
 541
 542 /* Get packet from user space buffer */
 543 static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
 544                                        struct iovec *iv, size_t count,
 545                                        int noblock)
 546 {
 547         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 548         struct sk_buff *skb;
 549         size_t len = count, align = 0;
 550         struct virtio_net_hdr gso = { 0 };
 551
 552         if (!(tun->flags & TUN_NO_PI)) {
 553                 if ((len -= sizeof(pi)) > count)
 554                         return -EINVAL;
 555
 556                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 557                         return -EFAULT;
 558         }
 559
 560         if (tun->flags & TUN_VNET_HDR) {
 561                 if ((len -= sizeof(gso)) > count)
 562                         return -EINVAL;
 563
 564                 if (memcpy_fromiovec((void *)&gso, iv, sizeof(gso)))
 565                         return -EFAULT;
 566
 567                 if (gso.hdr_len > len)
 568                         return -EINVAL;
 569         }
 570
 571         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 572                 align = NET_IP_ALIGN;
 573                 if (unlikely(len < ETH_HLEN ||
 574                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 575                         return -EINVAL;
 576         }
 577
 578         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 579         if (IS_ERR(skb)) {
 580                 if (PTR_ERR(skb) != -EAGAIN)
 581                         tun->dev->stats.rx_dropped++;
 582                 return PTR_ERR(skb);
 583         }
 584
 585         if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
 586                 tun->dev->stats.rx_dropped++;
 587                 kfree_skb(skb);
 588                 return -EFAULT;
 589         }
 590
 591         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 592                 if (!skb_partial_csum_set(skb, gso.csum_start,
 593                                           gso.csum_offset)) {
 594                         tun->dev->stats.rx_frame_errors++;
 595                         kfree_skb(skb);
 596                         return -EINVAL;
 597                 }
 598         } else if (tun->flags & TUN_NOCHECKSUM)
 599                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 600
 601         switch (tun->flags & TUN_TYPE_MASK) {
 602         case TUN_TUN_DEV:
 603                 if (tun->flags & TUN_NO_PI) {
 604                         switch (skb->data[0] & 0xf0) {
 605                         case 0x40:
 606                                 pi.proto = htons(ETH_P_IP);
 607                                 break;
 608                         case 0x60:
 609                                 pi.proto = htons(ETH_P_IPV6);
 610                                 break;
 611                         default:
 612                                 tun->dev->stats.rx_dropped++;
 613                                 kfree_skb(skb);
 614                                 return -EINVAL;
 615                         }
 616                 }
 617
 618                 skb_reset_mac_header(skb);
 619                 skb->protocol = pi.proto;
 620                 skb->dev = tun->dev;
 621                 break;
 622         case TUN_TAP_DEV:
 623                 skb->protocol = eth_type_trans(skb, tun->dev);
 624                 break;
 625         };
 626
 627         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 628                 pr_debug("GSO!\n");
 629                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 630                 case VIRTIO_NET_HDR_GSO_TCPV4:
 631                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 632                         break;
 633                 case VIRTIO_NET_HDR_GSO_TCPV6:
 634                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 635                         break;
 636                 default:
 637                         tun->dev->stats.rx_frame_errors++;
 638                         kfree_skb(skb);
 639                         return -EINVAL;
 640                 }
 641
 642                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 643                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 644
 645                 skb_shinfo(skb)->gso_size = gso.gso_size;
 646                 if (skb_shinfo(skb)->gso_size == 0) {
 647                         tun->dev->stats.rx_frame_errors++;
 648                         kfree_skb(skb);
 649                         return -EINVAL;
 650                 }
 651
 652                 /* Header must be checked, and gso_segs computed. */
 653                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 654                 skb_shinfo(skb)->gso_segs = 0;
 655         }
 656
 657         netif_rx_ni(skb);
 658
 659         tun->dev->stats.rx_packets++;
 660         tun->dev->stats.rx_bytes += len;
 661
 662         return count;
 663 }
 664
 665 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 666                               unsigned long count, loff_t pos)
 667 {
 668         struct file *file = iocb->ki_filp;
 669         struct tun_struct *tun = tun_get(file);
 670         ssize_t result;
 671
 672         if (!tun)
 673                 return -EBADFD;
 674
 675         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 676
 677         result = tun_get_user(tun, (struct iovec *)iv, iov_length(iv, count),
 678                               file->f_flags & O_NONBLOCK);
 679
 680         tun_put(tun);
 681         return result;
 682 }
 683
 684 /* Put packet to the user space buffer */
 685 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 686                                        struct sk_buff *skb,
 687                                        struct iovec *iv, int len)
 688 {
 689         struct tun_pi pi = { 0, skb->protocol };
 690         ssize_t total = 0;
 691
 692         if (!(tun->flags & TUN_NO_PI)) {
 693                 if ((len -= sizeof(pi)) < 0)
 694                         return -EINVAL;
 695
 696                 if (len < skb->len) {
 697                         /* Packet will be striped */
 698                         pi.flags |= TUN_PKT_STRIP;
 699                 }
 700
 701                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 702                         return -EFAULT;
 703                 total += sizeof(pi);
 704         }
 705
 706         if (tun->flags & TUN_VNET_HDR) {
 707                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 708                 if ((len -= sizeof(gso)) < 0)
 709                         return -EINVAL;
 710
 711                 if (skb_is_gso(skb)) {
 712                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 713
 714                         /* This is a hint as to how much should be linear. */
 715                         gso.hdr_len = skb_headlen(skb);
 716                         gso.gso_size = sinfo->gso_size;
 717                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 718                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 719                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 720                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 721                         else
 722                                 BUG();
 723                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 724                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 725                 } else
 726                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 727
 728                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 729                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 730                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 731                         gso.csum_offset = skb->csum_offset;
 732                 } /* else everything is zero */
 733
 734                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
 735                         return -EFAULT;
 736                 total += sizeof(gso);
 737         }
 738
 739         len = min_t(int, skb->len, len);
 740
 741         skb_copy_datagram_iovec(skb, 0, iv, len);
 742         total += len;
 743
 744         tun->dev->stats.tx_packets++;
 745         tun->dev->stats.tx_bytes += len;
 746
 747         return total;
 748 }
 749
 750 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 751                             unsigned long count, loff_t pos)
 752 {
 753         struct file *file = iocb->ki_filp;
 754         struct tun_file *tfile = file->private_data;
 755         struct tun_struct *tun = __tun_get(tfile);
 756         DECLARE_WAITQUEUE(wait, current);
 757         struct sk_buff *skb;
 758         ssize_t len, ret = 0;
 759
 760         if (!tun)
 761                 return -EBADFD;
 762
 763         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 764
 765         len = iov_length(iv, count);
 766         if (len < 0) {
 767                 ret = -EINVAL;
 768                 goto out;
 769         }
 770
 771         add_wait_queue(&tfile->read_wait, &wait);
 772         while (len) {
 773                 current->state = TASK_INTERRUPTIBLE;
 774
 775                 /* Read frames from the queue */
 776                 if (!(skb=skb_dequeue(&tun->readq))) {
 777                         if (file->f_flags & O_NONBLOCK) {
 778                                 ret = -EAGAIN;
 779                                 break;
 780                         }
 781                         if (signal_pending(current)) {
 782                                 ret = -ERESTARTSYS;
 783                                 break;
 784                         }
 785                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 786                                 ret = -EIO;
 787                                 break;
 788                         }
 789
 790                         /* Nothing to read, let's sleep */
 791                         schedule();
 792                         continue;
 793                 }
 794                 netif_wake_queue(tun->dev);
 795
 796                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 797                 kfree_skb(skb);
 798                 break;
 799         }
 800
 801         current->state = TASK_RUNNING;
 802         remove_wait_queue(&tfile->read_wait, &wait);
 803
 804 out:
 805         tun_put(tun);
 806         return ret;
 807 }
 808
 809 static void tun_setup(struct net_device *dev)
 810 {
 811         struct tun_struct *tun = netdev_priv(dev);
 812
 813         skb_queue_head_init(&tun->readq);
 814
 815         tun->owner = -1;
 816         tun->group = -1;
 817
 818         dev->ethtool_ops = &tun_ethtool_ops;
 819         dev->destructor = tun_free_netdev;
 820 }
 821
 822 /* Trivial set of netlink ops to allow deleting tun or tap
 823  * device with netlink.
 824  */
 825 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 826 {
 827         return -EINVAL;
 828 }
 829
 830 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 831         .kind           = DRV_NAME,
 832         .priv_size      = sizeof(struct tun_struct),
 833         .setup          = tun_setup,
 834         .validate       = tun_validate,
 835 };
 836
 837 static void tun_sock_write_space(struct sock *sk)
 838 {
 839         struct tun_struct *tun;
 840
 841         if (!sock_writeable(sk))
 842                 return;
 843
 844         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 845                 wake_up_interruptible_sync(sk->sk_sleep);
 846
 847         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 848                 return;
 849
 850         tun = container_of(sk, struct tun_sock, sk)->tun;
 851         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 852 }
 853
 854 static void tun_sock_destruct(struct sock *sk)
 855 {
 856         free_netdev(container_of(sk, struct tun_sock, sk)->tun->dev);
 857 }
 858
 859 static struct proto tun_proto = {
 860         .name           = "tun",
 861         .owner          = THIS_MODULE,
 862         .obj_size       = sizeof(struct tun_sock),
 863 };
 864
 865 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 866 {
 867         struct sock *sk;
 868         struct tun_struct *tun;
 869         struct net_device *dev;
 870         struct tun_file *tfile = file->private_data;
 871         int err;
 872
 873         dev = __dev_get_by_name(net, ifr->ifr_name);
 874         if (dev) {
 875                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 876                         tun = netdev_priv(dev);
 877                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
 878                         tun = netdev_priv(dev);
 879                 else
 880                         return -EINVAL;
 881
 882                 err = tun_attach(tun, file);
 883                 if (err < 0)
 884                         return err;
 885         }
 886         else {
 887                 char *name;
 888                 unsigned long flags = 0;
 889
 890                 err = -EINVAL;
 891
 892                 if (!capable(CAP_NET_ADMIN))
 893                         return -EPERM;
 894
 895                 /* Set dev type */
 896                 if (ifr->ifr_flags & IFF_TUN) {
 897                         /* TUN device */
 898                         flags |= TUN_TUN_DEV;
 899                         name = "tun%d";
 900                 } else if (ifr->ifr_flags & IFF_TAP) {
 901                         /* TAP device */
 902                         flags |= TUN_TAP_DEV;
 903                         name = "tap%d";
 904                 } else
 905                         goto failed;
 906
 907                 if (*ifr->ifr_name)
 908                         name = ifr->ifr_name;
 909
 910                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 911                                    tun_setup);
 912                 if (!dev)
 913                         return -ENOMEM;
 914
 915                 dev_net_set(dev, net);
 916                 dev->rtnl_link_ops = &tun_link_ops;
 917
 918                 tun = netdev_priv(dev);
 919                 tun->dev = dev;
 920                 tun->flags = flags;
 921                 tun->txflt.count = 0;
 922
 923                 err = -ENOMEM;
 924                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
 925                 if (!sk)
 926                         goto err_free_dev;
 927
 928                 sock_init_data(&tun->socket, sk);
 929                 sk->sk_write_space = tun_sock_write_space;
 930                 sk->sk_sndbuf = INT_MAX;
 931                 sk->sk_sleep = &tfile->read_wait;
 932
 933                 tun->sk = sk;
 934                 container_of(sk, struct tun_sock, sk)->tun = tun;
 935
 936                 tun_net_init(dev);
 937
 938                 if (strchr(dev->name, '%')) {
 939                         err = dev_alloc_name(dev, dev->name);
 940                         if (err < 0)
 941                                 goto err_free_sk;
 942                 }
 943
 944                 err = -EINVAL;
 945                 err = register_netdevice(tun->dev);
 946                 if (err < 0)
 947                         goto err_free_sk;
 948
 949                 sk->sk_destruct = tun_sock_destruct;
 950
 951                 err = tun_attach(tun, file);
 952                 if (err < 0)
 953                         goto failed;
 954         }
 955
 956         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 957
 958         if (ifr->ifr_flags & IFF_NO_PI)
 959                 tun->flags |= TUN_NO_PI;
 960         else
 961                 tun->flags &= ~TUN_NO_PI;
 962
 963         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 964                 tun->flags |= TUN_ONE_QUEUE;
 965         else
 966                 tun->flags &= ~TUN_ONE_QUEUE;
 967
 968         if (ifr->ifr_flags & IFF_VNET_HDR)
 969                 tun->flags |= TUN_VNET_HDR;
 970         else
 971                 tun->flags &= ~TUN_VNET_HDR;
 972
 973         /* Make sure persistent devices do not get stuck in
 974          * xoff state.
 975          */
 976         if (netif_running(tun->dev))
 977                 netif_wake_queue(tun->dev);
 978
 979         strcpy(ifr->ifr_name, tun->dev->name);
 980         return 0;
 981
 982  err_free_sk:
 983         sock_put(sk);
 984  err_free_dev:
 985         free_netdev(dev);
 986  failed:
 987         return err;
 988 }
 989
 990 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 991 {
 992         struct tun_struct *tun = tun_get(file);
 993
 994         if (!tun)
 995                 return -EBADFD;
 996
 997         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
 998
 999         strcpy(ifr->ifr_name, tun->dev->name);
1000
1001         ifr->ifr_flags = 0;
1002
1003         if (ifr->ifr_flags & TUN_TUN_DEV)
1004                 ifr->ifr_flags |= IFF_TUN;
1005         else
1006                 ifr->ifr_flags |= IFF_TAP;
1007
1008         if (tun->flags & TUN_NO_PI)
1009                 ifr->ifr_flags |= IFF_NO_PI;
1010
1011         if (tun->flags & TUN_ONE_QUEUE)
1012                 ifr->ifr_flags |= IFF_ONE_QUEUE;
1013
1014         if (tun->flags & TUN_VNET_HDR)
1015                 ifr->ifr_flags |= IFF_VNET_HDR;
1016
1017         tun_put(tun);
1018         return 0;
1019 }
1020
1021 /* This is like a cut-down ethtool ops, except done via tun fd so no
1022  * privs required. */
1023 static int set_offload(struct net_device *dev, unsigned long arg)
1024 {
1025         unsigned int old_features, features;
1026
1027         old_features = dev->features;
1028         /* Unset features, set them as we chew on the arg. */
1029         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1030                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
1031
1032         if (arg & TUN_F_CSUM) {
1033                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1034                 arg &= ~TUN_F_CSUM;
1035
1036                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1037                         if (arg & TUN_F_TSO_ECN) {
1038                                 features |= NETIF_F_TSO_ECN;
1039                                 arg &= ~TUN_F_TSO_ECN;
1040                         }
1041                         if (arg & TUN_F_TSO4)
1042                                 features |= NETIF_F_TSO;
1043                         if (arg & TUN_F_TSO6)
1044                                 features |= NETIF_F_TSO6;
1045                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1046                 }
1047         }
1048
1049         /* This gives the user a way to test for new features in future by
1050          * trying to set them. */
1051         if (arg)
1052                 return -EINVAL;
1053
1054         dev->features = features;
1055         if (old_features != dev->features)
1056                 netdev_features_change(dev);
1057
1058         return 0;
1059 }
1060
1061 static int tun_chr_ioctl(struct inode *inode, struct file *file,
1062                          unsigned int cmd, unsigned long arg)
1063 {
1064         struct tun_file *tfile = file->private_data;
1065         struct tun_struct *tun;
1066         void __user* argp = (void __user*)arg;
1067         struct ifreq ifr;
1068         int sndbuf;
1069         int ret;
1070
1071         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1072                 if (copy_from_user(&ifr, argp, sizeof ifr))
1073                         return -EFAULT;
1074
1075         if (cmd == TUNGETFEATURES) {
1076                 /* Currently this just means: "what IFF flags are valid?".
1077                  * This is needed because we never checked for invalid flags on
1078                  * TUNSETIFF. */
1079                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1080                                 IFF_VNET_HDR,
1081                                 (unsigned int __user*)argp);
1082         }
1083
1084         tun = __tun_get(tfile);
1085         if (cmd == TUNSETIFF && !tun) {
1086                 int err;
1087
1088                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1089
1090                 rtnl_lock();
1091                 err = tun_set_iff(tfile->net, file, &ifr);
1092                 rtnl_unlock();
1093
1094                 if (err)
1095                         return err;
1096
1097                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1098                         return -EFAULT;
1099                 return 0;
1100         }
1101
1102
1103         if (!tun)
1104                 return -EBADFD;
1105
1106         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1107
1108         ret = 0;
1109         switch (cmd) {
1110         case TUNGETIFF:
1111                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
1112                 if (ret)
1113                         break;
1114
1115                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1116                         ret = -EFAULT;
1117                 break;
1118
1119         case TUNSETNOCSUM:
1120                 /* Disable/Enable checksum */
1121                 if (arg)
1122                         tun->flags |= TUN_NOCHECKSUM;
1123                 else
1124                         tun->flags &= ~TUN_NOCHECKSUM;
1125
1126                 DBG(KERN_INFO "%s: checksum %s\n",
1127                     tun->dev->name, arg ? "disabled" : "enabled");
1128                 break;
1129
1130         case TUNSETPERSIST:
1131                 /* Disable/Enable persist mode */
1132                 if (arg)
1133                         tun->flags |= TUN_PERSIST;
1134                 else
1135                         tun->flags &= ~TUN_PERSIST;
1136
1137                 DBG(KERN_INFO "%s: persist %s\n",
1138                     tun->dev->name, arg ? "enabled" : "disabled");
1139                 break;
1140
1141         case TUNSETOWNER:
1142                 /* Set owner of the device */
1143                 tun->owner = (uid_t) arg;
1144
1145                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1146                 break;
1147
1148         case TUNSETGROUP:
1149                 /* Set group of the device */
1150                 tun->group= (gid_t) arg;
1151
1152                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1153                 break;
1154
1155         case TUNSETLINK:
1156                 /* Only allow setting the type when the interface is down */
1157                 rtnl_lock();
1158                 if (tun->dev->flags & IFF_UP) {
1159                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1160                                 tun->dev->name);
1161                         ret = -EBUSY;
1162                 } else {
1163                         tun->dev->type = (int) arg;
1164                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1165                         ret = 0;
1166                 }
1167                 rtnl_unlock();
1168                 break;
1169
1170 #ifdef TUN_DEBUG
1171         case TUNSETDEBUG:
1172                 tun->debug = arg;
1173                 break;
1174 #endif
1175         case TUNSETOFFLOAD:
1176                 rtnl_lock();
1177                 ret = set_offload(tun->dev, arg);
1178                 rtnl_unlock();
1179                 break;
1180
1181         case TUNSETTXFILTER:
1182                 /* Can be set only for TAPs */
1183                 ret = -EINVAL;
1184                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1185                         break;
1186                 rtnl_lock();
1187                 ret = update_filter(&tun->txflt, (void __user *)arg);
1188                 rtnl_unlock();
1189                 break;
1190
1191         case SIOCGIFHWADDR:
1192                 /* Get hw addres */
1193                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1194                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1195                 if (copy_to_user(argp, &ifr, sizeof ifr))
1196                         ret = -EFAULT;
1197                 break;
1198
1199         case SIOCSIFHWADDR:
1200                 /* Set hw address */
1201                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1202                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1203
1204                 rtnl_lock();
1205                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1206                 rtnl_unlock();
1207                 break;
1208
1209         case TUNGETSNDBUF:
1210                 sndbuf = tun->sk->sk_sndbuf;
1211                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1212                         ret = -EFAULT;
1213                 break;
1214
1215         case TUNSETSNDBUF:
1216                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1217                         ret = -EFAULT;
1218                         break;
1219                 }
1220
1221                 tun->sk->sk_sndbuf = sndbuf;
1222                 break;
1223
1224         default:
1225                 ret = -EINVAL;
1226                 break;
1227         };
1228
1229         tun_put(tun);
1230         return ret;
1231 }
1232
1233 static int tun_chr_fasync(int fd, struct file *file, int on)
1234 {
1235         struct tun_struct *tun = tun_get(file);
1236         int ret;
1237
1238         if (!tun)
1239                 return -EBADFD;
1240
1241         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1242
1243         lock_kernel();
1244         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1245                 goto out;
1246
1247         if (on) {
1248                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1249                 if (ret)
1250                         goto out;
1251                 tun->flags |= TUN_FASYNC;
1252         } else
1253                 tun->flags &= ~TUN_FASYNC;
1254         ret = 0;
1255 out:
1256         unlock_kernel();
1257         tun_put(tun);
1258         return ret;
1259 }
1260
1261 static int tun_chr_open(struct inode *inode, struct file * file)
1262 {
1263         struct tun_file *tfile;
1264         cycle_kernel_lock();
1265         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1266
1267         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1268         if (!tfile)
1269                 return -ENOMEM;
1270         atomic_set(&tfile->count, 0);
1271         tfile->tun = NULL;
1272         tfile->net = get_net(current->nsproxy->net_ns);
1273         init_waitqueue_head(&tfile->read_wait);
1274         file->private_data = tfile;
1275         return 0;
1276 }
1277
1278 static int tun_chr_close(struct inode *inode, struct file *file)
1279 {
1280         struct tun_file *tfile = file->private_data;
1281         struct tun_struct *tun = __tun_get(tfile);
1282
1283
1284         if (tun) {
1285                 DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1286
1287                 rtnl_lock();
1288                 __tun_detach(tun);
1289
1290                 /* If desireable, unregister the netdevice. */
1291                 if (!(tun->flags & TUN_PERSIST))
1292                         unregister_netdevice(tun->dev);
1293
1294                 rtnl_unlock();
1295         }
1296
1297         tun = tfile->tun;
1298         if (tun)
1299                 sock_put(tun->sk);
1300
1301         put_net(tfile->net);
1302         kfree(tfile);
1303
1304         return 0;
1305 }
1306
1307 static const struct file_operations tun_fops = {
1308         .owner  = THIS_MODULE,
1309         .llseek = no_llseek,
1310         .read  = do_sync_read,
1311         .aio_read  = tun_chr_aio_read,
1312         .write = do_sync_write,
1313         .aio_write = tun_chr_aio_write,
1314         .poll   = tun_chr_poll,
1315         .ioctl  = tun_chr_ioctl,
1316         .open   = tun_chr_open,
1317         .release = tun_chr_close,
1318         .fasync = tun_chr_fasync
1319 };
1320
1321 static struct miscdevice tun_miscdev = {
1322         .minor = TUN_MINOR,
1323         .name = "tun",
1324         .fops = &tun_fops,
1325 };
1326
1327 /* ethtool interface */
1328
1329 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1330 {
1331         cmd->supported          = 0;
1332         cmd->advertising        = 0;
1333         cmd->speed              = SPEED_10;
1334         cmd->duplex             = DUPLEX_FULL;
1335         cmd->port               = PORT_TP;
1336         cmd->phy_address        = 0;
1337         cmd->transceiver        = XCVR_INTERNAL;
1338         cmd->autoneg            = AUTONEG_DISABLE;
1339         cmd->maxtxpkt           = 0;
1340         cmd->maxrxpkt           = 0;
1341         return 0;
1342 }
1343
1344 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1345 {
1346         struct tun_struct *tun = netdev_priv(dev);
1347
1348         strcpy(info->driver, DRV_NAME);
1349         strcpy(info->version, DRV_VERSION);
1350         strcpy(info->fw_version, "N/A");
1351
1352         switch (tun->flags & TUN_TYPE_MASK) {
1353         case TUN_TUN_DEV:
1354                 strcpy(info->bus_info, "tun");
1355                 break;
1356         case TUN_TAP_DEV:
1357                 strcpy(info->bus_info, "tap");
1358                 break;
1359         }
1360 }
1361
1362 static u32 tun_get_msglevel(struct net_device *dev)
1363 {
1364 #ifdef TUN_DEBUG
1365         struct tun_struct *tun = netdev_priv(dev);
1366         return tun->debug;
1367 #else
1368         return -EOPNOTSUPP;
1369 #endif
1370 }
1371
1372 static void tun_set_msglevel(struct net_device *dev, u32 value)
1373 {
1374 #ifdef TUN_DEBUG
1375         struct tun_struct *tun = netdev_priv(dev);
1376         tun->debug = value;
1377 #endif
1378 }
1379
1380 static u32 tun_get_link(struct net_device *dev)
1381 {
1382         struct tun_struct *tun = netdev_priv(dev);
1383         return !!tun->tfile;
1384 }
1385
1386 static u32 tun_get_rx_csum(struct net_device *dev)
1387 {
1388         struct tun_struct *tun = netdev_priv(dev);
1389         return (tun->flags & TUN_NOCHECKSUM) == 0;
1390 }
1391
1392 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1393 {
1394         struct tun_struct *tun = netdev_priv(dev);
1395         if (data)
1396                 tun->flags &= ~TUN_NOCHECKSUM;
1397         else
1398                 tun->flags |= TUN_NOCHECKSUM;
1399         return 0;
1400 }
1401
1402 static const struct ethtool_ops tun_ethtool_ops = {
1403         .get_settings   = tun_get_settings,
1404         .get_drvinfo    = tun_get_drvinfo,
1405         .get_msglevel   = tun_get_msglevel,
1406         .set_msglevel   = tun_set_msglevel,
1407         .get_link       = tun_get_link,
1408         .get_rx_csum    = tun_get_rx_csum,
1409         .set_rx_csum    = tun_set_rx_csum
1410 };
1411
1412
1413 static int __init tun_init(void)
1414 {
1415         int ret = 0;
1416
1417         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1418         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1419
1420         ret = rtnl_link_register(&tun_link_ops);
1421         if (ret) {
1422                 printk(KERN_ERR "tun: Can't register link_ops\n");
1423                 goto err_linkops;
1424         }
1425
1426         ret = misc_register(&tun_miscdev);
1427         if (ret) {
1428                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1429                 goto err_misc;
1430         }
1431         return  0;
1432 err_misc:
1433         rtnl_link_unregister(&tun_link_ops);
1434 err_linkops:
1435         return ret;
1436 }
1437
1438 static void tun_cleanup(void)
1439 {
1440         misc_deregister(&tun_miscdev);
1441         rtnl_link_unregister(&tun_link_ops);
1442 }
1443
1444 module_init(tun_init);
1445 module_exit(tun_cleanup);
1446 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1447 MODULE_AUTHOR(DRV_COPYRIGHT);
1448 MODULE_LICENSE("GPL");
1449 MODULE_ALIAS_MISCDEV(TUN_MINOR);