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