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  *  Brian Braunstein <linuxkernel@bristyle.com> 2007/03/23
  22  *    Fixed hw address handling.  Now net_device.dev_addr is kept consistent
  23  *    with tun.dev_addr when the address is set by this module.
  24  *
  25  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  26  *    Add TUNSETLINK ioctl to set the link encapsulation
  27  *
  28  *  Mark Smith <markzzzsmith@yahoo.com.au>
  29  *   Use random_ether_addr() for tap MAC address.
  30  *
  31  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  32  *    Fixes in packet dropping, queue length setting and queue wakeup.
  33  *    Increased default tx queue length.
  34  *    Added ethtool API.
  35  *    Minor cleanups
  36  *
  37  *  Daniel Podlejski <underley@underley.eu.org>
  38  *    Modifications for 2.3.99-pre5 kernel.
  39  */
  40
  41 #define DRV_NAME        "tun"
  42 #define DRV_VERSION     "1.6"
  43 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  44 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  45
  46 #include <linux/module.h>
  47 #include <linux/errno.h>
  48 #include <linux/kernel.h>
  49 #include <linux/major.h>
  50 #include <linux/slab.h>
  51 #include <linux/poll.h>
  52 #include <linux/fcntl.h>
  53 #include <linux/init.h>
  54 #include <linux/skbuff.h>
  55 #include <linux/netdevice.h>
  56 #include <linux/etherdevice.h>
  57 #include <linux/miscdevice.h>
  58 #include <linux/ethtool.h>
  59 #include <linux/rtnetlink.h>
  60 #include <linux/if.h>
  61 #include <linux/if_arp.h>
  62 #include <linux/if_ether.h>
  63 #include <linux/if_tun.h>
  64 #include <linux/crc32.h>
  65 #include <net/net_namespace.h>
  66
  67 #include <asm/system.h>
  68 #include <asm/uaccess.h>
  69
  70 /* Uncomment to enable debugging */
  71 /* #define TUN_DEBUG 1 */
  72
  73 #ifdef TUN_DEBUG
  74 static int debug;
  75
  76 #define DBG  if(tun->debug)printk
  77 #define DBG1 if(debug==2)printk
  78 #else
  79 #define DBG( a... )
  80 #define DBG1( a... )
  81 #endif
  82
  83 struct tun_struct {
  84         struct list_head        list;
  85         unsigned long           flags;
  86         int                     attached;
  87         uid_t                   owner;
  88         gid_t                   group;
  89
  90         wait_queue_head_t       read_wait;
  91         struct sk_buff_head     readq;
  92
  93         struct net_device       *dev;
  94
  95         struct fasync_struct    *fasync;
  96
  97         unsigned long if_flags;
  98         u8 dev_addr[ETH_ALEN];
  99         u32 chr_filter[2];
 100         u32 net_filter[2];
 101
 102 #ifdef TUN_DEBUG
 103         int debug;
 104 #endif
 105 };
 106
 107 /* Network device part of the driver */
 108
 109 static LIST_HEAD(tun_dev_list);
 110 static const struct ethtool_ops tun_ethtool_ops;
 111
 112 /* Net device open. */
 113 static int tun_net_open(struct net_device *dev)
 114 {
 115         netif_start_queue(dev);
 116         return 0;
 117 }
 118
 119 /* Net device close. */
 120 static int tun_net_close(struct net_device *dev)
 121 {
 122         netif_stop_queue(dev);
 123         return 0;
 124 }
 125
 126 /* Net device start xmit */
 127 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 128 {
 129         struct tun_struct *tun = netdev_priv(dev);
 130
 131         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 132
 133         /* Drop packet if interface is not attached */
 134         if (!tun->attached)
 135                 goto drop;
 136
 137         /* Packet dropping */
 138         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
 139                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 140                         /* Normal queueing mode. */
 141                         /* Packet scheduler handles dropping of further packets. */
 142                         netif_stop_queue(dev);
 143
 144                         /* We won't see all dropped packets individually, so overrun
 145                          * error is more appropriate. */
 146                         dev->stats.tx_fifo_errors++;
 147                 } else {
 148                         /* Single queue mode.
 149                          * Driver handles dropping of all packets itself. */
 150                         goto drop;
 151                 }
 152         }
 153
 154         /* Queue packet */
 155         skb_queue_tail(&tun->readq, skb);
 156         dev->trans_start = jiffies;
 157
 158         /* Notify and wake up reader process */
 159         if (tun->flags & TUN_FASYNC)
 160                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 161         wake_up_interruptible(&tun->read_wait);
 162         return 0;
 163
 164 drop:
 165         dev->stats.tx_dropped++;
 166         kfree_skb(skb);
 167         return 0;
 168 }
 169
 170 /** Add the specified Ethernet address to this multicast filter. */
 171 static void
 172 add_multi(u32* filter, const u8* addr)
 173 {
 174         int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
 175         filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
 176 }
 177
 178 /** Remove the specified Ethernet addres from this multicast filter. */
 179 static void
 180 del_multi(u32* filter, const u8* addr)
 181 {
 182         int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
 183         filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31));
 184 }
 185
 186 /** Update the list of multicast groups to which the network device belongs.
 187  * This list is used to filter packets being sent from the character device to
 188  * the network device. */
 189 static void
 190 tun_net_mclist(struct net_device *dev)
 191 {
 192         struct tun_struct *tun = netdev_priv(dev);
 193         const struct dev_mc_list *mclist;
 194         int i;
 195         DECLARE_MAC_BUF(mac);
 196         DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
 197                         dev->name, dev->mc_count);
 198         memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 199         for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
 200                         i++, mclist = mclist->next) {
 201                 add_multi(tun->net_filter, mclist->dmi_addr);
 202                 DBG(KERN_DEBUG "%s: tun_net_mclist: %s\n",
 203                     dev->name, print_mac(mac, mclist->dmi_addr));
 204         }
 205 }
 206
 207 #define MIN_MTU 68
 208 #define MAX_MTU 65535
 209
 210 static int
 211 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 212 {
 213         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 214                 return -EINVAL;
 215         dev->mtu = new_mtu;
 216         return 0;
 217 }
 218
 219 /* Initialize net device. */
 220 static void tun_net_init(struct net_device *dev)
 221 {
 222         struct tun_struct *tun = netdev_priv(dev);
 223
 224         switch (tun->flags & TUN_TYPE_MASK) {
 225         case TUN_TUN_DEV:
 226                 /* Point-to-Point TUN Device */
 227                 dev->hard_header_len = 0;
 228                 dev->addr_len = 0;
 229                 dev->mtu = 1500;
 230                 dev->change_mtu = tun_net_change_mtu;
 231
 232                 /* Zero header length */
 233                 dev->type = ARPHRD_NONE;
 234                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 235                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 236                 break;
 237
 238         case TUN_TAP_DEV:
 239                 /* Ethernet TAP Device */
 240                 dev->set_multicast_list = tun_net_mclist;
 241
 242                 ether_setup(dev);
 243                 dev->change_mtu = tun_net_change_mtu;
 244
 245                 /* random address already created for us by tun_set_iff, use it */
 246                 memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) );
 247
 248                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 249                 break;
 250         }
 251 }
 252
 253 /* Character device part */
 254
 255 /* Poll */
 256 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 257 {
 258         struct tun_struct *tun = file->private_data;
 259         unsigned int mask = POLLOUT | POLLWRNORM;
 260
 261         if (!tun)
 262                 return -EBADFD;
 263
 264         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 265
 266         poll_wait(file, &tun->read_wait, wait);
 267
 268         if (!skb_queue_empty(&tun->readq))
 269                 mask |= POLLIN | POLLRDNORM;
 270
 271         return mask;
 272 }
 273
 274 /* Get packet from user space buffer */
 275 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
 276 {
 277         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
 278         struct sk_buff *skb;
 279         size_t len = count, align = 0;
 280
 281         if (!(tun->flags & TUN_NO_PI)) {
 282                 if ((len -= sizeof(pi)) > count)
 283                         return -EINVAL;
 284
 285                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 286                         return -EFAULT;
 287         }
 288
 289         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 290                 align = NET_IP_ALIGN;
 291                 if (unlikely(len < ETH_HLEN))
 292                         return -EINVAL;
 293         }
 294
 295         if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
 296                 tun->dev->stats.rx_dropped++;
 297                 return -ENOMEM;
 298         }
 299
 300         if (align)
 301                 skb_reserve(skb, align);
 302         if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
 303                 tun->dev->stats.rx_dropped++;
 304                 kfree_skb(skb);
 305                 return -EFAULT;
 306         }
 307
 308         switch (tun->flags & TUN_TYPE_MASK) {
 309         case TUN_TUN_DEV:
 310                 skb_reset_mac_header(skb);
 311                 skb->protocol = pi.proto;
 312                 skb->dev = tun->dev;
 313                 break;
 314         case TUN_TAP_DEV:
 315                 skb->protocol = eth_type_trans(skb, tun->dev);
 316                 break;
 317         };
 318
 319         if (tun->flags & TUN_NOCHECKSUM)
 320                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 321
 322         netif_rx_ni(skb);
 323         tun->dev->last_rx = jiffies;
 324
 325         tun->dev->stats.rx_packets++;
 326         tun->dev->stats.rx_bytes += len;
 327
 328         return count;
 329 }
 330
 331 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 332                               unsigned long count, loff_t pos)
 333 {
 334         struct tun_struct *tun = iocb->ki_filp->private_data;
 335
 336         if (!tun)
 337                 return -EBADFD;
 338
 339         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 340
 341         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
 342 }
 343
 344 /* Put packet to the user space buffer */
 345 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 346                                        struct sk_buff *skb,
 347                                        struct iovec *iv, int len)
 348 {
 349         struct tun_pi pi = { 0, skb->protocol };
 350         ssize_t total = 0;
 351
 352         if (!(tun->flags & TUN_NO_PI)) {
 353                 if ((len -= sizeof(pi)) < 0)
 354                         return -EINVAL;
 355
 356                 if (len < skb->len) {
 357                         /* Packet will be striped */
 358                         pi.flags |= TUN_PKT_STRIP;
 359                 }
 360
 361                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 362                         return -EFAULT;
 363                 total += sizeof(pi);
 364         }
 365
 366         len = min_t(int, skb->len, len);
 367
 368         skb_copy_datagram_iovec(skb, 0, iv, len);
 369         total += len;
 370
 371         tun->dev->stats.tx_packets++;
 372         tun->dev->stats.tx_bytes += len;
 373
 374         return total;
 375 }
 376
 377 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 378                             unsigned long count, loff_t pos)
 379 {
 380         struct file *file = iocb->ki_filp;
 381         struct tun_struct *tun = file->private_data;
 382         DECLARE_WAITQUEUE(wait, current);
 383         struct sk_buff *skb;
 384         ssize_t len, ret = 0;
 385         DECLARE_MAC_BUF(mac);
 386
 387         if (!tun)
 388                 return -EBADFD;
 389
 390         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 391
 392         len = iov_length(iv, count);
 393         if (len < 0)
 394                 return -EINVAL;
 395
 396         add_wait_queue(&tun->read_wait, &wait);
 397         while (len) {
 398                 const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 399                 u8 addr[ ETH_ALEN];
 400                 int bit_nr;
 401
 402                 current->state = TASK_INTERRUPTIBLE;
 403
 404                 /* Read frames from the queue */
 405                 if (!(skb=skb_dequeue(&tun->readq))) {
 406                         if (file->f_flags & O_NONBLOCK) {
 407                                 ret = -EAGAIN;
 408                                 break;
 409                         }
 410                         if (signal_pending(current)) {
 411                                 ret = -ERESTARTSYS;
 412                                 break;
 413                         }
 414
 415                         /* Nothing to read, let's sleep */
 416                         schedule();
 417                         continue;
 418                 }
 419                 netif_wake_queue(tun->dev);
 420
 421                 /** Decide whether to accept this packet. This code is designed to
 422                  * behave identically to an Ethernet interface. Accept the packet if
 423                  * - we are promiscuous.
 424                  * - the packet is addressed to us.
 425                  * - the packet is broadcast.
 426                  * - the packet is multicast and
 427                  *   - we are multicast promiscous.
 428                  *   - we belong to the multicast group.
 429                  */
 430                 skb_copy_from_linear_data(skb, addr, min_t(size_t, sizeof addr,
 431                                                                    skb->len));
 432                 bit_nr = ether_crc(sizeof addr, addr) >> 26;
 433                 if ((tun->if_flags & IFF_PROMISC) ||
 434                                 memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
 435                                 memcmp(addr, ones, sizeof addr) == 0 ||
 436                                 (((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
 437                                   (addr[0] == 0x33 && addr[1] == 0x33)) &&
 438                                  ((tun->if_flags & IFF_ALLMULTI) ||
 439                                   (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
 440                         DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %s\n",
 441                                         tun->dev->name, print_mac(mac, addr));
 442                         ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 443                         kfree_skb(skb);
 444                         break;
 445                 } else {
 446                         DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n",
 447                                         tun->dev->name, print_mac(mac, addr));
 448                         kfree_skb(skb);
 449                         continue;
 450                 }
 451         }
 452
 453         current->state = TASK_RUNNING;
 454         remove_wait_queue(&tun->read_wait, &wait);
 455
 456         return ret;
 457 }
 458
 459 static void tun_setup(struct net_device *dev)
 460 {
 461         struct tun_struct *tun = netdev_priv(dev);
 462
 463         skb_queue_head_init(&tun->readq);
 464         init_waitqueue_head(&tun->read_wait);
 465
 466         tun->owner = -1;
 467         tun->group = -1;
 468
 469         dev->open = tun_net_open;
 470         dev->hard_start_xmit = tun_net_xmit;
 471         dev->stop = tun_net_close;
 472         dev->ethtool_ops = &tun_ethtool_ops;
 473         dev->destructor = free_netdev;
 474 }
 475
 476 static struct tun_struct *tun_get_by_name(const char *name)
 477 {
 478         struct tun_struct *tun;
 479
 480         ASSERT_RTNL();
 481         list_for_each_entry(tun, &tun_dev_list, list) {
 482                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
 483                     return tun;
 484         }
 485
 486         return NULL;
 487 }
 488
 489 static int tun_set_iff(struct file *file, struct ifreq *ifr)
 490 {
 491         struct tun_struct *tun;
 492         struct net_device *dev;
 493         int err;
 494
 495         tun = tun_get_by_name(ifr->ifr_name);
 496         if (tun) {
 497                 if (tun->attached)
 498                         return -EBUSY;
 499
 500                 /* Check permissions */
 501                 if (((tun->owner != -1 &&
 502                       current->euid != tun->owner) ||
 503                      (tun->group != -1 &&
 504                       current->egid != tun->group)) &&
 505                      !capable(CAP_NET_ADMIN))
 506                         return -EPERM;
 507         }
 508         else if (__dev_get_by_name(&init_net, ifr->ifr_name))
 509                 return -EINVAL;
 510         else {
 511                 char *name;
 512                 unsigned long flags = 0;
 513
 514                 err = -EINVAL;
 515
 516                 if (!capable(CAP_NET_ADMIN))
 517                         return -EPERM;
 518
 519                 /* Set dev type */
 520                 if (ifr->ifr_flags & IFF_TUN) {
 521                         /* TUN device */
 522                         flags |= TUN_TUN_DEV;
 523                         name = "tun%d";
 524                 } else if (ifr->ifr_flags & IFF_TAP) {
 525                         /* TAP device */
 526                         flags |= TUN_TAP_DEV;
 527                         name = "tap%d";
 528                 } else
 529                         goto failed;
 530
 531                 if (*ifr->ifr_name)
 532                         name = ifr->ifr_name;
 533
 534                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 535                                    tun_setup);
 536                 if (!dev)
 537                         return -ENOMEM;
 538
 539                 tun = netdev_priv(dev);
 540                 tun->dev = dev;
 541                 tun->flags = flags;
 542                 /* Be promiscuous by default to maintain previous behaviour. */
 543                 tun->if_flags = IFF_PROMISC;
 544                 /* Generate random Ethernet address. */
 545                 *(__be16 *)tun->dev_addr = htons(0x00FF);
 546                 get_random_bytes(tun->dev_addr + sizeof(u16), 4);
 547                 memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 548
 549                 tun_net_init(dev);
 550
 551                 if (strchr(dev->name, '%')) {
 552                         err = dev_alloc_name(dev, dev->name);
 553                         if (err < 0)
 554                                 goto err_free_dev;
 555                 }
 556
 557                 err = register_netdevice(tun->dev);
 558                 if (err < 0)
 559                         goto err_free_dev;
 560
 561                 list_add(&tun->list, &tun_dev_list);
 562         }
 563
 564         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 565
 566         if (ifr->ifr_flags & IFF_NO_PI)
 567                 tun->flags |= TUN_NO_PI;
 568         else
 569                 tun->flags &= ~TUN_NO_PI;
 570
 571         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 572                 tun->flags |= TUN_ONE_QUEUE;
 573         else
 574                 tun->flags &= ~TUN_ONE_QUEUE;
 575
 576         file->private_data = tun;
 577         tun->attached = 1;
 578
 579         strcpy(ifr->ifr_name, tun->dev->name);
 580         return 0;
 581
 582  err_free_dev:
 583         free_netdev(dev);
 584  failed:
 585         return err;
 586 }
 587
 588 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 589                          unsigned int cmd, unsigned long arg)
 590 {
 591         struct tun_struct *tun = file->private_data;
 592         void __user* argp = (void __user*)arg;
 593         struct ifreq ifr;
 594         DECLARE_MAC_BUF(mac);
 595
 596         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 597                 if (copy_from_user(&ifr, argp, sizeof ifr))
 598                         return -EFAULT;
 599
 600         if (cmd == TUNSETIFF && !tun) {
 601                 int err;
 602
 603                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 604
 605                 rtnl_lock();
 606                 err = tun_set_iff(file, &ifr);
 607                 rtnl_unlock();
 608
 609                 if (err)
 610                         return err;
 611
 612                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 613                         return -EFAULT;
 614                 return 0;
 615         }
 616
 617         if (!tun)
 618                 return -EBADFD;
 619
 620         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 621
 622         switch (cmd) {
 623         case TUNSETNOCSUM:
 624                 /* Disable/Enable checksum */
 625                 if (arg)
 626                         tun->flags |= TUN_NOCHECKSUM;
 627                 else
 628                         tun->flags &= ~TUN_NOCHECKSUM;
 629
 630                 DBG(KERN_INFO "%s: checksum %s\n",
 631                     tun->dev->name, arg ? "disabled" : "enabled");
 632                 break;
 633
 634         case TUNSETPERSIST:
 635                 /* Disable/Enable persist mode */
 636                 if (arg)
 637                         tun->flags |= TUN_PERSIST;
 638                 else
 639                         tun->flags &= ~TUN_PERSIST;
 640
 641                 DBG(KERN_INFO "%s: persist %s\n",
 642                     tun->dev->name, arg ? "enabled" : "disabled");
 643                 break;
 644
 645         case TUNSETOWNER:
 646                 /* Set owner of the device */
 647                 tun->owner = (uid_t) arg;
 648
 649                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 650                 break;
 651
 652         case TUNSETGROUP:
 653                 /* Set group of the device */
 654                 tun->group= (gid_t) arg;
 655
 656                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 657                 break;
 658
 659         case TUNSETLINK:
 660                 /* Only allow setting the type when the interface is down */
 661                 if (tun->dev->flags & IFF_UP) {
 662                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 663                                 tun->dev->name);
 664                         return -EBUSY;
 665                 } else {
 666                         tun->dev->type = (int) arg;
 667                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 668                 }
 669                 break;
 670
 671 #ifdef TUN_DEBUG
 672         case TUNSETDEBUG:
 673                 tun->debug = arg;
 674                 break;
 675 #endif
 676
 677         case SIOCGIFFLAGS:
 678                 ifr.ifr_flags = tun->if_flags;
 679                 if (copy_to_user( argp, &ifr, sizeof ifr))
 680                         return -EFAULT;
 681                 return 0;
 682
 683         case SIOCSIFFLAGS:
 684                 /** Set the character device's interface flags. Currently only
 685                  * IFF_PROMISC and IFF_ALLMULTI are used. */
 686                 tun->if_flags = ifr.ifr_flags;
 687                 DBG(KERN_INFO "%s: interface flags 0x%lx\n",
 688                                 tun->dev->name, tun->if_flags);
 689                 return 0;
 690
 691         case SIOCGIFHWADDR:
 692                 /* Note: the actual net device's address may be different */
 693                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
 694                                 min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 695                 if (copy_to_user( argp, &ifr, sizeof ifr))
 696                         return -EFAULT;
 697                 return 0;
 698
 699         case SIOCSIFHWADDR:
 700         {
 701                 /* try to set the actual net device's hw address */
 702                 int ret;
 703
 704                 rtnl_lock();
 705                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
 706                 rtnl_unlock();
 707
 708                 if (ret == 0) {
 709                         /** Set the character device's hardware address. This is used when
 710                          * filtering packets being sent from the network device to the character
 711                          * device. */
 712                         memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
 713                                         min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 714                         DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
 715                                         tun->dev->name,
 716                                         tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
 717                                         tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
 718                 }
 719
 720                 return  ret;
 721         }
 722
 723         case SIOCADDMULTI:
 724                 /** Add the specified group to the character device's multicast filter
 725                  * list. */
 726                 add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 727                 DBG(KERN_DEBUG "%s: add multi: %s\n",
 728                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 729                 return 0;
 730
 731         case SIOCDELMULTI:
 732                 /** Remove the specified group from the character device's multicast
 733                  * filter list. */
 734                 del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 735                 DBG(KERN_DEBUG "%s: del multi: %s\n",
 736                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 737                 return 0;
 738
 739         default:
 740                 return -EINVAL;
 741         };
 742
 743         return 0;
 744 }
 745
 746 static int tun_chr_fasync(int fd, struct file *file, int on)
 747 {
 748         struct tun_struct *tun = file->private_data;
 749         int ret;
 750
 751         if (!tun)
 752                 return -EBADFD;
 753
 754         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 755
 756         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
 757                 return ret;
 758
 759         if (on) {
 760                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
 761                 if (ret)
 762                         return ret;
 763                 tun->flags |= TUN_FASYNC;
 764         } else
 765                 tun->flags &= ~TUN_FASYNC;
 766
 767         return 0;
 768 }
 769
 770 static int tun_chr_open(struct inode *inode, struct file * file)
 771 {
 772         DBG1(KERN_INFO "tunX: tun_chr_open\n");
 773         file->private_data = NULL;
 774         return 0;
 775 }
 776
 777 static int tun_chr_close(struct inode *inode, struct file *file)
 778 {
 779         struct tun_struct *tun = file->private_data;
 780
 781         if (!tun)
 782                 return 0;
 783
 784         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 785
 786         tun_chr_fasync(-1, file, 0);
 787
 788         rtnl_lock();
 789
 790         /* Detach from net device */
 791         file->private_data = NULL;
 792         tun->attached = 0;
 793
 794         /* Drop read queue */
 795         skb_queue_purge(&tun->readq);
 796
 797         if (!(tun->flags & TUN_PERSIST)) {
 798                 list_del(&tun->list);
 799                 unregister_netdevice(tun->dev);
 800         }
 801
 802         rtnl_unlock();
 803
 804         return 0;
 805 }
 806
 807 static const struct file_operations tun_fops = {
 808         .owner  = THIS_MODULE,
 809         .llseek = no_llseek,
 810         .read  = do_sync_read,
 811         .aio_read  = tun_chr_aio_read,
 812         .write = do_sync_write,
 813         .aio_write = tun_chr_aio_write,
 814         .poll   = tun_chr_poll,
 815         .ioctl  = tun_chr_ioctl,
 816         .open   = tun_chr_open,
 817         .release = tun_chr_close,
 818         .fasync = tun_chr_fasync
 819 };
 820
 821 static struct miscdevice tun_miscdev = {
 822         .minor = TUN_MINOR,
 823         .name = "tun",
 824         .fops = &tun_fops,
 825 };
 826
 827 /* ethtool interface */
 828
 829 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 830 {
 831         cmd->supported          = 0;
 832         cmd->advertising        = 0;
 833         cmd->speed              = SPEED_10;
 834         cmd->duplex             = DUPLEX_FULL;
 835         cmd->port               = PORT_TP;
 836         cmd->phy_address        = 0;
 837         cmd->transceiver        = XCVR_INTERNAL;
 838         cmd->autoneg            = AUTONEG_DISABLE;
 839         cmd->maxtxpkt           = 0;
 840         cmd->maxrxpkt           = 0;
 841         return 0;
 842 }
 843
 844 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 845 {
 846         struct tun_struct *tun = netdev_priv(dev);
 847
 848         strcpy(info->driver, DRV_NAME);
 849         strcpy(info->version, DRV_VERSION);
 850         strcpy(info->fw_version, "N/A");
 851
 852         switch (tun->flags & TUN_TYPE_MASK) {
 853         case TUN_TUN_DEV:
 854                 strcpy(info->bus_info, "tun");
 855                 break;
 856         case TUN_TAP_DEV:
 857                 strcpy(info->bus_info, "tap");
 858                 break;
 859         }
 860 }
 861
 862 static u32 tun_get_msglevel(struct net_device *dev)
 863 {
 864 #ifdef TUN_DEBUG
 865         struct tun_struct *tun = netdev_priv(dev);
 866         return tun->debug;
 867 #else
 868         return -EOPNOTSUPP;
 869 #endif
 870 }
 871
 872 static void tun_set_msglevel(struct net_device *dev, u32 value)
 873 {
 874 #ifdef TUN_DEBUG
 875         struct tun_struct *tun = netdev_priv(dev);
 876         tun->debug = value;
 877 #endif
 878 }
 879
 880 static u32 tun_get_link(struct net_device *dev)
 881 {
 882         struct tun_struct *tun = netdev_priv(dev);
 883         return tun->attached;
 884 }
 885
 886 static u32 tun_get_rx_csum(struct net_device *dev)
 887 {
 888         struct tun_struct *tun = netdev_priv(dev);
 889         return (tun->flags & TUN_NOCHECKSUM) == 0;
 890 }
 891
 892 static int tun_set_rx_csum(struct net_device *dev, u32 data)
 893 {
 894         struct tun_struct *tun = netdev_priv(dev);
 895         if (data)
 896                 tun->flags &= ~TUN_NOCHECKSUM;
 897         else
 898                 tun->flags |= TUN_NOCHECKSUM;
 899         return 0;
 900 }
 901
 902 static const struct ethtool_ops tun_ethtool_ops = {
 903         .get_settings   = tun_get_settings,
 904         .get_drvinfo    = tun_get_drvinfo,
 905         .get_msglevel   = tun_get_msglevel,
 906         .set_msglevel   = tun_set_msglevel,
 907         .get_link       = tun_get_link,
 908         .get_rx_csum    = tun_get_rx_csum,
 909         .set_rx_csum    = tun_set_rx_csum
 910 };
 911
 912 static int __init tun_init(void)
 913 {
 914         int ret = 0;
 915
 916         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
 917         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
 918
 919         ret = misc_register(&tun_miscdev);
 920         if (ret)
 921                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
 922         return ret;
 923 }
 924
 925 static void tun_cleanup(void)
 926 {
 927         struct tun_struct *tun, *nxt;
 928
 929         misc_deregister(&tun_miscdev);
 930
 931         rtnl_lock();
 932         list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
 933                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
 934                 unregister_netdevice(tun->dev);
 935         }
 936         rtnl_unlock();
 937
 938 }
 939
 940 module_init(tun_init);
 941 module_exit(tun_cleanup);
 942 MODULE_DESCRIPTION(DRV_DESCRIPTION);
 943 MODULE_AUTHOR(DRV_COPYRIGHT);
 944 MODULE_LICENSE("GPL");
 945 MODULE_ALIAS_MISCDEV(TUN_MINOR);