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