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