git.oblomov.eu Git - linux-2.6/blob - drivers/net/tun.c

   1 /*
   2  *  TUN - Universal TUN/TAP device driver.
   3  *  Copyright (C) 1999-2002 Maxim Krasnyansky <maxk@qualcomm.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  $Id: tun.c,v 1.15 2002/03/01 02:44:24 maxk Exp $
  16  */
  17
  18 /*
  19  *  Changes:
  20  *
  21  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use random_ether_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define DRV_NAME        "tun"
  38 #define DRV_VERSION     "1.6"
  39 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  40 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  41
  42 #include <linux/module.h>
  43 #include <linux/errno.h>
  44 #include <linux/kernel.h>
  45 #include <linux/major.h>
  46 #include <linux/slab.h>
  47 #include <linux/smp_lock.h>
  48 #include <linux/poll.h>
  49 #include <linux/fcntl.h>
  50 #include <linux/init.h>
  51 #include <linux/skbuff.h>
  52 #include <linux/netdevice.h>
  53 #include <linux/etherdevice.h>
  54 #include <linux/miscdevice.h>
  55 #include <linux/ethtool.h>
  56 #include <linux/rtnetlink.h>
  57 #include <linux/if.h>
  58 #include <linux/if_arp.h>
  59 #include <linux/if_ether.h>
  60 #include <linux/if_tun.h>
  61 #include <linux/crc32.h>
  62 #include <linux/nsproxy.h>
  63 #include <linux/virtio_net.h>
  64 #include <net/net_namespace.h>
  65 #include <net/netns/generic.h>
  66 #include <net/rtnetlink.h>
  67 #include <net/sock.h>
  68
  69 #include <asm/system.h>
  70 #include <asm/uaccess.h>
  71
  72 /* Uncomment to enable debugging */
  73 /* #define TUN_DEBUG 1 */
  74
  75 #ifdef TUN_DEBUG
  76 static int debug;
  77
  78 #define DBG  if(tun->debug)printk
  79 #define DBG1 if(debug==2)printk
  80 #else
  81 #define DBG( a... )
  82 #define DBG1( a... )
  83 #endif
  84
  85 #define FLT_EXACT_COUNT 8
  86 struct tap_filter {
  87         unsigned int    count;    /* Number of addrs. Zero means disabled */
  88         u32             mask[2];  /* Mask of the hashed addrs */
  89         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
  90 };
  91
  92 struct tun_file {
  93         atomic_t count;
  94         struct tun_struct *tun;
  95         struct net *net;
  96         wait_queue_head_t       read_wait;
  97 };
  98
  99 struct tun_sock;
 100
 101 struct tun_struct {
 102         struct tun_file         *tfile;
 103         unsigned int            flags;
 104         uid_t                   owner;
 105         gid_t                   group;
 106
 107         struct sk_buff_head     readq;
 108
 109         struct net_device       *dev;
 110         struct fasync_struct    *fasync;
 111
 112         struct tap_filter       txflt;
 113         struct sock             *sk;
 114         struct socket           socket;
 115
 116 #ifdef TUN_DEBUG
 117         int debug;
 118 #endif
 119 };
 120
 121 struct tun_sock {
 122         struct sock             sk;
 123         struct tun_struct       *tun;
 124 };
 125
 126 static inline struct tun_sock *tun_sk(struct sock *sk)
 127 {
 128         return container_of(sk, struct tun_sock, sk);
 129 }
 130
 131 static int tun_attach(struct tun_struct *tun, struct file *file)
 132 {
 133         struct tun_file *tfile = file->private_data;
 134         const struct cred *cred = current_cred();
 135         int err;
 136
 137         ASSERT_RTNL();
 138
 139         /* Check permissions */
 140         if (((tun->owner != -1 && cred->euid != tun->owner) ||
 141              (tun->group != -1 && !in_egroup_p(tun->group))) &&
 142                 !capable(CAP_NET_ADMIN))
 143                 return -EPERM;
 144
 145         netif_tx_lock_bh(tun->dev);
 146
 147         err = -EINVAL;
 148         if (tfile->tun)
 149                 goto out;
 150
 151         err = -EBUSY;
 152         if (tun->tfile)
 153                 goto out;
 154
 155         err = 0;
 156         tfile->tun = tun;
 157         tun->tfile = tfile;
 158         dev_hold(tun->dev);
 159         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)
 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                         return -EINVAL;
 570         }
 571
 572         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 573         if (IS_ERR(skb)) {
 574                 if (PTR_ERR(skb) != -EAGAIN)
 575                         tun->dev->stats.rx_dropped++;
 576                 return PTR_ERR(skb);
 577         }
 578
 579         if (skb_copy_datagram_from_iovec(skb, 0, iv, len)) {
 580                 tun->dev->stats.rx_dropped++;
 581                 kfree_skb(skb);
 582                 return -EFAULT;
 583         }
 584
 585         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 586                 if (!skb_partial_csum_set(skb, gso.csum_start,
 587                                           gso.csum_offset)) {
 588                         tun->dev->stats.rx_frame_errors++;
 589                         kfree_skb(skb);
 590                         return -EINVAL;
 591                 }
 592         } else if (tun->flags & TUN_NOCHECKSUM)
 593                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 594
 595         switch (tun->flags & TUN_TYPE_MASK) {
 596         case TUN_TUN_DEV:
 597                 if (tun->flags & TUN_NO_PI) {
 598                         switch (skb->data[0] & 0xf0) {
 599                         case 0x40:
 600                                 pi.proto = htons(ETH_P_IP);
 601                                 break;
 602                         case 0x60:
 603                                 pi.proto = htons(ETH_P_IPV6);
 604                                 break;
 605                         default:
 606                                 tun->dev->stats.rx_dropped++;
 607                                 kfree_skb(skb);
 608                                 return -EINVAL;
 609                         }
 610                 }
 611
 612                 skb_reset_mac_header(skb);
 613                 skb->protocol = pi.proto;
 614                 skb->dev = tun->dev;
 615                 break;
 616         case TUN_TAP_DEV:
 617                 skb->protocol = eth_type_trans(skb, tun->dev);
 618                 break;
 619         };
 620
 621         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 622                 pr_debug("GSO!\n");
 623                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 624                 case VIRTIO_NET_HDR_GSO_TCPV4:
 625                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 626                         break;
 627                 case VIRTIO_NET_HDR_GSO_TCPV6:
 628                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 629                         break;
 630                 default:
 631                         tun->dev->stats.rx_frame_errors++;
 632                         kfree_skb(skb);
 633                         return -EINVAL;
 634                 }
 635
 636                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 637                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 638
 639                 skb_shinfo(skb)->gso_size = gso.gso_size;
 640                 if (skb_shinfo(skb)->gso_size == 0) {
 641                         tun->dev->stats.rx_frame_errors++;
 642                         kfree_skb(skb);
 643                         return -EINVAL;
 644                 }
 645
 646                 /* Header must be checked, and gso_segs computed. */
 647                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 648                 skb_shinfo(skb)->gso_segs = 0;
 649         }
 650
 651         netif_rx_ni(skb);
 652
 653         tun->dev->stats.rx_packets++;
 654         tun->dev->stats.rx_bytes += len;
 655
 656         return count;
 657 }
 658
 659 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 660                               unsigned long count, loff_t pos)
 661 {
 662         struct file *file = iocb->ki_filp;
 663         struct tun_struct *tun = tun_get(file);
 664         ssize_t result;
 665
 666         if (!tun)
 667                 return -EBADFD;
 668
 669         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 670
 671         result = tun_get_user(tun, (struct iovec *)iv, iov_length(iv, count),
 672                               file->f_flags & O_NONBLOCK);
 673
 674         tun_put(tun);
 675         return result;
 676 }
 677
 678 /* Put packet to the user space buffer */
 679 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 680                                        struct sk_buff *skb,
 681                                        struct iovec *iv, int len)
 682 {
 683         struct tun_pi pi = { 0, skb->protocol };
 684         ssize_t total = 0;
 685
 686         if (!(tun->flags & TUN_NO_PI)) {
 687                 if ((len -= sizeof(pi)) < 0)
 688                         return -EINVAL;
 689
 690                 if (len < skb->len) {
 691                         /* Packet will be striped */
 692                         pi.flags |= TUN_PKT_STRIP;
 693                 }
 694
 695                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 696                         return -EFAULT;
 697                 total += sizeof(pi);
 698         }
 699
 700         if (tun->flags & TUN_VNET_HDR) {
 701                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 702                 if ((len -= sizeof(gso)) < 0)
 703                         return -EINVAL;
 704
 705                 if (skb_is_gso(skb)) {
 706                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 707
 708                         /* This is a hint as to how much should be linear. */
 709                         gso.hdr_len = skb_headlen(skb);
 710                         gso.gso_size = sinfo->gso_size;
 711                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 712                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 713                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 714                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 715                         else
 716                                 BUG();
 717                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 718                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 719                 } else
 720                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 721
 722                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 723                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 724                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 725                         gso.csum_offset = skb->csum_offset;
 726                 } /* else everything is zero */
 727
 728                 if (unlikely(memcpy_toiovec(iv, (void *)&gso, sizeof(gso))))
 729                         return -EFAULT;
 730                 total += sizeof(gso);
 731         }
 732
 733         len = min_t(int, skb->len, len);
 734
 735         skb_copy_datagram_iovec(skb, 0, iv, len);
 736         total += len;
 737
 738         tun->dev->stats.tx_packets++;
 739         tun->dev->stats.tx_bytes += len;
 740
 741         return total;
 742 }
 743
 744 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 745                             unsigned long count, loff_t pos)
 746 {
 747         struct file *file = iocb->ki_filp;
 748         struct tun_file *tfile = file->private_data;
 749         struct tun_struct *tun = __tun_get(tfile);
 750         DECLARE_WAITQUEUE(wait, current);
 751         struct sk_buff *skb;
 752         ssize_t len, ret = 0;
 753
 754         if (!tun)
 755                 return -EBADFD;
 756
 757         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 758
 759         len = iov_length(iv, count);
 760         if (len < 0) {
 761                 ret = -EINVAL;
 762                 goto out;
 763         }
 764
 765         add_wait_queue(&tfile->read_wait, &wait);
 766         while (len) {
 767                 current->state = TASK_INTERRUPTIBLE;
 768
 769                 /* Read frames from the queue */
 770                 if (!(skb=skb_dequeue(&tun->readq))) {
 771                         if (file->f_flags & O_NONBLOCK) {
 772                                 ret = -EAGAIN;
 773                                 break;
 774                         }
 775                         if (signal_pending(current)) {
 776                                 ret = -ERESTARTSYS;
 777                                 break;
 778                         }
 779                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 780                                 ret = -EIO;
 781                                 break;
 782                         }
 783
 784                         /* Nothing to read, let's sleep */
 785                         schedule();
 786                         continue;
 787                 }
 788                 netif_wake_queue(tun->dev);
 789
 790                 ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 791                 kfree_skb(skb);
 792                 break;
 793         }
 794
 795         current->state = TASK_RUNNING;
 796         remove_wait_queue(&tfile->read_wait, &wait);
 797
 798 out:
 799         tun_put(tun);
 800         return ret;
 801 }
 802
 803 static void tun_setup(struct net_device *dev)
 804 {
 805         struct tun_struct *tun = netdev_priv(dev);
 806
 807         skb_queue_head_init(&tun->readq);
 808
 809         tun->owner = -1;
 810         tun->group = -1;
 811
 812         dev->ethtool_ops = &tun_ethtool_ops;
 813         dev->destructor = free_netdev;
 814 }
 815
 816 /* Trivial set of netlink ops to allow deleting tun or tap
 817  * device with netlink.
 818  */
 819 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 820 {
 821         return -EINVAL;
 822 }
 823
 824 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 825         .kind           = DRV_NAME,
 826         .priv_size      = sizeof(struct tun_struct),
 827         .setup          = tun_setup,
 828         .validate       = tun_validate,
 829 };
 830
 831 static void tun_sock_write_space(struct sock *sk)
 832 {
 833         struct tun_struct *tun;
 834
 835         if (!sock_writeable(sk))
 836                 return;
 837
 838         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 839                 wake_up_interruptible_sync(sk->sk_sleep);
 840
 841         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 842                 return;
 843
 844         tun = container_of(sk, struct tun_sock, sk)->tun;
 845         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 846 }
 847
 848 static void tun_sock_destruct(struct sock *sk)
 849 {
 850         dev_put(container_of(sk, struct tun_sock, sk)->tun->dev);
 851 }
 852
 853 static struct proto tun_proto = {
 854         .name           = "tun",
 855         .owner          = THIS_MODULE,
 856         .obj_size       = sizeof(struct tun_sock),
 857 };
 858
 859 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 860 {
 861         struct sock *sk;
 862         struct tun_struct *tun;
 863         struct net_device *dev;
 864         struct tun_file *tfile = file->private_data;
 865         int err;
 866
 867         dev = __dev_get_by_name(net, ifr->ifr_name);
 868         if (dev) {
 869                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 870                         tun = netdev_priv(dev);
 871                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
 872                         tun = netdev_priv(dev);
 873                 else
 874                         return -EINVAL;
 875
 876                 err = tun_attach(tun, file);
 877                 if (err < 0)
 878                         return err;
 879         }
 880         else {
 881                 char *name;
 882                 unsigned long flags = 0;
 883
 884                 err = -EINVAL;
 885
 886                 if (!capable(CAP_NET_ADMIN))
 887                         return -EPERM;
 888
 889                 /* Set dev type */
 890                 if (ifr->ifr_flags & IFF_TUN) {
 891                         /* TUN device */
 892                         flags |= TUN_TUN_DEV;
 893                         name = "tun%d";
 894                 } else if (ifr->ifr_flags & IFF_TAP) {
 895                         /* TAP device */
 896                         flags |= TUN_TAP_DEV;
 897                         name = "tap%d";
 898                 } else
 899                         goto failed;
 900
 901                 if (*ifr->ifr_name)
 902                         name = ifr->ifr_name;
 903
 904                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 905                                    tun_setup);
 906                 if (!dev)
 907                         return -ENOMEM;
 908
 909                 dev_net_set(dev, net);
 910                 dev->rtnl_link_ops = &tun_link_ops;
 911
 912                 tun = netdev_priv(dev);
 913                 tun->dev = dev;
 914                 tun->flags = flags;
 915                 tun->txflt.count = 0;
 916
 917                 err = -ENOMEM;
 918                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
 919                 if (!sk)
 920                         goto err_free_dev;
 921
 922                 /* This ref count is for tun->sk. */
 923                 dev_hold(dev);
 924                 sock_init_data(&tun->socket, sk);
 925                 sk->sk_write_space = tun_sock_write_space;
 926                 sk->sk_destruct = tun_sock_destruct;
 927                 sk->sk_sndbuf = INT_MAX;
 928                 sk->sk_sleep = &tfile->read_wait;
 929
 930                 tun->sk = sk;
 931                 container_of(sk, struct tun_sock, sk)->tun = tun;
 932
 933                 tun_net_init(dev);
 934
 935                 if (strchr(dev->name, '%')) {
 936                         err = dev_alloc_name(dev, dev->name);
 937                         if (err < 0)
 938                                 goto err_free_sk;
 939                 }
 940
 941                 err = -EINVAL;
 942                 err = register_netdevice(tun->dev);
 943                 if (err < 0)
 944                         goto err_free_dev;
 945
 946                 err = tun_attach(tun, file);
 947                 if (err < 0)
 948                         goto err_free_dev;
 949         }
 950
 951         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 952
 953         if (ifr->ifr_flags & IFF_NO_PI)
 954                 tun->flags |= TUN_NO_PI;
 955         else
 956                 tun->flags &= ~TUN_NO_PI;
 957
 958         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 959                 tun->flags |= TUN_ONE_QUEUE;
 960         else
 961                 tun->flags &= ~TUN_ONE_QUEUE;
 962
 963         if (ifr->ifr_flags & IFF_VNET_HDR)
 964                 tun->flags |= TUN_VNET_HDR;
 965         else
 966                 tun->flags &= ~TUN_VNET_HDR;
 967
 968         /* Make sure persistent devices do not get stuck in
 969          * xoff state.
 970          */
 971         if (netif_running(tun->dev))
 972                 netif_wake_queue(tun->dev);
 973
 974         strcpy(ifr->ifr_name, tun->dev->name);
 975         return 0;
 976
 977  err_free_sk:
 978         sock_put(sk);
 979  err_free_dev:
 980         free_netdev(dev);
 981  failed:
 982         return err;
 983 }
 984
 985 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 986 {
 987         struct tun_struct *tun = tun_get(file);
 988
 989         if (!tun)
 990                 return -EBADFD;
 991
 992         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
 993
 994         strcpy(ifr->ifr_name, tun->dev->name);
 995
 996         ifr->ifr_flags = 0;
 997
 998         if (ifr->ifr_flags & TUN_TUN_DEV)
 999                 ifr->ifr_flags |= IFF_TUN;
1000         else
1001                 ifr->ifr_flags |= IFF_TAP;
1002
1003         if (tun->flags & TUN_NO_PI)
1004                 ifr->ifr_flags |= IFF_NO_PI;
1005
1006         if (tun->flags & TUN_ONE_QUEUE)
1007                 ifr->ifr_flags |= IFF_ONE_QUEUE;
1008
1009         if (tun->flags & TUN_VNET_HDR)
1010                 ifr->ifr_flags |= IFF_VNET_HDR;
1011
1012         tun_put(tun);
1013         return 0;
1014 }
1015
1016 /* This is like a cut-down ethtool ops, except done via tun fd so no
1017  * privs required. */
1018 static int set_offload(struct net_device *dev, unsigned long arg)
1019 {
1020         unsigned int old_features, features;
1021
1022         old_features = dev->features;
1023         /* Unset features, set them as we chew on the arg. */
1024         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1025                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
1026
1027         if (arg & TUN_F_CSUM) {
1028                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1029                 arg &= ~TUN_F_CSUM;
1030
1031                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1032                         if (arg & TUN_F_TSO_ECN) {
1033                                 features |= NETIF_F_TSO_ECN;
1034                                 arg &= ~TUN_F_TSO_ECN;
1035                         }
1036                         if (arg & TUN_F_TSO4)
1037                                 features |= NETIF_F_TSO;
1038                         if (arg & TUN_F_TSO6)
1039                                 features |= NETIF_F_TSO6;
1040                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1041                 }
1042         }
1043
1044         /* This gives the user a way to test for new features in future by
1045          * trying to set them. */
1046         if (arg)
1047                 return -EINVAL;
1048
1049         dev->features = features;
1050         if (old_features != dev->features)
1051                 netdev_features_change(dev);
1052
1053         return 0;
1054 }
1055
1056 static int tun_chr_ioctl(struct inode *inode, struct file *file,
1057                          unsigned int cmd, unsigned long arg)
1058 {
1059         struct tun_file *tfile = file->private_data;
1060         struct tun_struct *tun;
1061         void __user* argp = (void __user*)arg;
1062         struct ifreq ifr;
1063         int sndbuf;
1064         int ret;
1065
1066         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1067                 if (copy_from_user(&ifr, argp, sizeof ifr))
1068                         return -EFAULT;
1069
1070         if (cmd == TUNGETFEATURES) {
1071                 /* Currently this just means: "what IFF flags are valid?".
1072                  * This is needed because we never checked for invalid flags on
1073                  * TUNSETIFF. */
1074                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1075                                 IFF_VNET_HDR,
1076                                 (unsigned int __user*)argp);
1077         }
1078
1079         tun = __tun_get(tfile);
1080         if (cmd == TUNSETIFF && !tun) {
1081                 int err;
1082
1083                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1084
1085                 rtnl_lock();
1086                 err = tun_set_iff(tfile->net, file, &ifr);
1087                 rtnl_unlock();
1088
1089                 if (err)
1090                         return err;
1091
1092                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1093                         return -EFAULT;
1094                 return 0;
1095         }
1096
1097
1098         if (!tun)
1099                 return -EBADFD;
1100
1101         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1102
1103         ret = 0;
1104         switch (cmd) {
1105         case TUNGETIFF:
1106                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
1107                 if (ret)
1108                         break;
1109
1110                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1111                         ret = -EFAULT;
1112                 break;
1113
1114         case TUNSETNOCSUM:
1115                 /* Disable/Enable checksum */
1116                 if (arg)
1117                         tun->flags |= TUN_NOCHECKSUM;
1118                 else
1119                         tun->flags &= ~TUN_NOCHECKSUM;
1120
1121                 DBG(KERN_INFO "%s: checksum %s\n",
1122                     tun->dev->name, arg ? "disabled" : "enabled");
1123                 break;
1124
1125         case TUNSETPERSIST:
1126                 /* Disable/Enable persist mode */
1127                 if (arg)
1128                         tun->flags |= TUN_PERSIST;
1129                 else
1130                         tun->flags &= ~TUN_PERSIST;
1131
1132                 DBG(KERN_INFO "%s: persist %s\n",
1133                     tun->dev->name, arg ? "enabled" : "disabled");
1134                 break;
1135
1136         case TUNSETOWNER:
1137                 /* Set owner of the device */
1138                 tun->owner = (uid_t) arg;
1139
1140                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1141                 break;
1142
1143         case TUNSETGROUP:
1144                 /* Set group of the device */
1145                 tun->group= (gid_t) arg;
1146
1147                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1148                 break;
1149
1150         case TUNSETLINK:
1151                 /* Only allow setting the type when the interface is down */
1152                 rtnl_lock();
1153                 if (tun->dev->flags & IFF_UP) {
1154                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1155                                 tun->dev->name);
1156                         ret = -EBUSY;
1157                 } else {
1158                         tun->dev->type = (int) arg;
1159                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1160                         ret = 0;
1161                 }
1162                 rtnl_unlock();
1163                 break;
1164
1165 #ifdef TUN_DEBUG
1166         case TUNSETDEBUG:
1167                 tun->debug = arg;
1168                 break;
1169 #endif
1170         case TUNSETOFFLOAD:
1171                 rtnl_lock();
1172                 ret = set_offload(tun->dev, arg);
1173                 rtnl_unlock();
1174                 break;
1175
1176         case TUNSETTXFILTER:
1177                 /* Can be set only for TAPs */
1178                 ret = -EINVAL;
1179                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1180                         break;
1181                 rtnl_lock();
1182                 ret = update_filter(&tun->txflt, (void __user *)arg);
1183                 rtnl_unlock();
1184                 break;
1185
1186         case SIOCGIFHWADDR:
1187                 /* Get hw addres */
1188                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1189                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1190                 if (copy_to_user(argp, &ifr, sizeof ifr))
1191                         ret = -EFAULT;
1192                 break;
1193
1194         case SIOCSIFHWADDR:
1195                 /* Set hw address */
1196                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1197                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1198
1199                 rtnl_lock();
1200                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1201                 rtnl_unlock();
1202                 break;
1203
1204         case TUNGETSNDBUF:
1205                 sndbuf = tun->sk->sk_sndbuf;
1206                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1207                         ret = -EFAULT;
1208                 break;
1209
1210         case TUNSETSNDBUF:
1211                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1212                         ret = -EFAULT;
1213                         break;
1214                 }
1215
1216                 tun->sk->sk_sndbuf = sndbuf;
1217                 break;
1218
1219         default:
1220                 ret = -EINVAL;
1221                 break;
1222         };
1223
1224         tun_put(tun);
1225         return ret;
1226 }
1227
1228 static int tun_chr_fasync(int fd, struct file *file, int on)
1229 {
1230         struct tun_struct *tun = tun_get(file);
1231         int ret;
1232
1233         if (!tun)
1234                 return -EBADFD;
1235
1236         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1237
1238         lock_kernel();
1239         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1240                 goto out;
1241
1242         if (on) {
1243                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1244                 if (ret)
1245                         goto out;
1246                 tun->flags |= TUN_FASYNC;
1247         } else
1248                 tun->flags &= ~TUN_FASYNC;
1249         ret = 0;
1250 out:
1251         unlock_kernel();
1252         tun_put(tun);
1253         return ret;
1254 }
1255
1256 static int tun_chr_open(struct inode *inode, struct file * file)
1257 {
1258         struct tun_file *tfile;
1259         cycle_kernel_lock();
1260         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1261
1262         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1263         if (!tfile)
1264                 return -ENOMEM;
1265         atomic_set(&tfile->count, 0);
1266         tfile->tun = NULL;
1267         tfile->net = get_net(current->nsproxy->net_ns);
1268         init_waitqueue_head(&tfile->read_wait);
1269         file->private_data = tfile;
1270         return 0;
1271 }
1272
1273 static int tun_chr_close(struct inode *inode, struct file *file)
1274 {
1275         struct tun_file *tfile = file->private_data;
1276         struct tun_struct *tun = __tun_get(tfile);
1277
1278
1279         if (tun) {
1280                 DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1281
1282                 rtnl_lock();
1283                 __tun_detach(tun);
1284
1285                 /* If desireable, unregister the netdevice. */
1286                 if (!(tun->flags & TUN_PERSIST)) {
1287                         sock_put(tun->sk);
1288                         unregister_netdevice(tun->dev);
1289                 }
1290
1291                 rtnl_unlock();
1292         }
1293
1294         put_net(tfile->net);
1295         kfree(tfile);
1296
1297         return 0;
1298 }
1299
1300 static const struct file_operations tun_fops = {
1301         .owner  = THIS_MODULE,
1302         .llseek = no_llseek,
1303         .read  = do_sync_read,
1304         .aio_read  = tun_chr_aio_read,
1305         .write = do_sync_write,
1306         .aio_write = tun_chr_aio_write,
1307         .poll   = tun_chr_poll,
1308         .ioctl  = tun_chr_ioctl,
1309         .open   = tun_chr_open,
1310         .release = tun_chr_close,
1311         .fasync = tun_chr_fasync
1312 };
1313
1314 static struct miscdevice tun_miscdev = {
1315         .minor = TUN_MINOR,
1316         .name = "tun",
1317         .fops = &tun_fops,
1318 };
1319
1320 /* ethtool interface */
1321
1322 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1323 {
1324         cmd->supported          = 0;
1325         cmd->advertising        = 0;
1326         cmd->speed              = SPEED_10;
1327         cmd->duplex             = DUPLEX_FULL;
1328         cmd->port               = PORT_TP;
1329         cmd->phy_address        = 0;
1330         cmd->transceiver        = XCVR_INTERNAL;
1331         cmd->autoneg            = AUTONEG_DISABLE;
1332         cmd->maxtxpkt           = 0;
1333         cmd->maxrxpkt           = 0;
1334         return 0;
1335 }
1336
1337 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1338 {
1339         struct tun_struct *tun = netdev_priv(dev);
1340
1341         strcpy(info->driver, DRV_NAME);
1342         strcpy(info->version, DRV_VERSION);
1343         strcpy(info->fw_version, "N/A");
1344
1345         switch (tun->flags & TUN_TYPE_MASK) {
1346         case TUN_TUN_DEV:
1347                 strcpy(info->bus_info, "tun");
1348                 break;
1349         case TUN_TAP_DEV:
1350                 strcpy(info->bus_info, "tap");
1351                 break;
1352         }
1353 }
1354
1355 static u32 tun_get_msglevel(struct net_device *dev)
1356 {
1357 #ifdef TUN_DEBUG
1358         struct tun_struct *tun = netdev_priv(dev);
1359         return tun->debug;
1360 #else
1361         return -EOPNOTSUPP;
1362 #endif
1363 }
1364
1365 static void tun_set_msglevel(struct net_device *dev, u32 value)
1366 {
1367 #ifdef TUN_DEBUG
1368         struct tun_struct *tun = netdev_priv(dev);
1369         tun->debug = value;
1370 #endif
1371 }
1372
1373 static u32 tun_get_link(struct net_device *dev)
1374 {
1375         struct tun_struct *tun = netdev_priv(dev);
1376         return !!tun->tfile;
1377 }
1378
1379 static u32 tun_get_rx_csum(struct net_device *dev)
1380 {
1381         struct tun_struct *tun = netdev_priv(dev);
1382         return (tun->flags & TUN_NOCHECKSUM) == 0;
1383 }
1384
1385 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1386 {
1387         struct tun_struct *tun = netdev_priv(dev);
1388         if (data)
1389                 tun->flags &= ~TUN_NOCHECKSUM;
1390         else
1391                 tun->flags |= TUN_NOCHECKSUM;
1392         return 0;
1393 }
1394
1395 static const struct ethtool_ops tun_ethtool_ops = {
1396         .get_settings   = tun_get_settings,
1397         .get_drvinfo    = tun_get_drvinfo,
1398         .get_msglevel   = tun_get_msglevel,
1399         .set_msglevel   = tun_set_msglevel,
1400         .get_link       = tun_get_link,
1401         .get_rx_csum    = tun_get_rx_csum,
1402         .set_rx_csum    = tun_set_rx_csum
1403 };
1404
1405
1406 static int __init tun_init(void)
1407 {
1408         int ret = 0;
1409
1410         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1411         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1412
1413         ret = rtnl_link_register(&tun_link_ops);
1414         if (ret) {
1415                 printk(KERN_ERR "tun: Can't register link_ops\n");
1416                 goto err_linkops;
1417         }
1418
1419         ret = misc_register(&tun_miscdev);
1420         if (ret) {
1421                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1422                 goto err_misc;
1423         }
1424         return  0;
1425 err_misc:
1426         rtnl_link_unregister(&tun_link_ops);
1427 err_linkops:
1428         return ret;
1429 }
1430
1431 static void tun_cleanup(void)
1432 {
1433         misc_deregister(&tun_miscdev);
1434         rtnl_link_unregister(&tun_link_ops);
1435 }
1436
1437 module_init(tun_init);
1438 module_exit(tun_cleanup);
1439 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1440 MODULE_AUTHOR(DRV_COPYRIGHT);
1441 MODULE_LICENSE("GPL");
1442 MODULE_ALIAS_MISCDEV(TUN_MINOR);