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