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                         dev->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         dev->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         DECLARE_MAC_BUF(mac);
 163         DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
 164                         dev->name, dev->mc_count);
 165         memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 166         for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
 167                         i++, mclist = mclist->next) {
 168                 add_multi(tun->net_filter, mclist->dmi_addr);
 169                 DBG(KERN_DEBUG "%s: tun_net_mclist: %s\n",
 170                     dev->name, print_mac(mac, mclist->dmi_addr));
 171         }
 172 }
 173
 174 #define MIN_MTU 68
 175 #define MAX_MTU 65535
 176
 177 static int
 178 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 179 {
 180         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 181                 return -EINVAL;
 182         dev->mtu = new_mtu;
 183         return 0;
 184 }
 185
 186 /* Initialize net device. */
 187 static void tun_net_init(struct net_device *dev)
 188 {
 189         struct tun_struct *tun = netdev_priv(dev);
 190
 191         switch (tun->flags & TUN_TYPE_MASK) {
 192         case TUN_TUN_DEV:
 193                 /* Point-to-Point TUN Device */
 194                 dev->hard_header_len = 0;
 195                 dev->addr_len = 0;
 196                 dev->mtu = 1500;
 197                 dev->change_mtu = tun_net_change_mtu;
 198
 199                 /* Zero header length */
 200                 dev->type = ARPHRD_NONE;
 201                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 202                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 203                 break;
 204
 205         case TUN_TAP_DEV:
 206                 /* Ethernet TAP Device */
 207                 dev->set_multicast_list = tun_net_mclist;
 208
 209                 ether_setup(dev);
 210                 dev->change_mtu = tun_net_change_mtu;
 211
 212                 /* random address already created for us by tun_set_iff, use it */
 213                 memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) );
 214
 215                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 216                 break;
 217         }
 218 }
 219
 220 /* Character device part */
 221
 222 /* Poll */
 223 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 224 {
 225         struct tun_struct *tun = file->private_data;
 226         unsigned int mask = POLLOUT | POLLWRNORM;
 227
 228         if (!tun)
 229                 return -EBADFD;
 230
 231         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 232
 233         poll_wait(file, &tun->read_wait, wait);
 234
 235         if (!skb_queue_empty(&tun->readq))
 236                 mask |= POLLIN | POLLRDNORM;
 237
 238         return mask;
 239 }
 240
 241 /* Get packet from user space buffer */
 242 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
 243 {
 244         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
 245         struct sk_buff *skb;
 246         size_t len = count, align = 0;
 247
 248         if (!(tun->flags & TUN_NO_PI)) {
 249                 if ((len -= sizeof(pi)) > count)
 250                         return -EINVAL;
 251
 252                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 253                         return -EFAULT;
 254         }
 255
 256         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV)
 257                 align = NET_IP_ALIGN;
 258
 259         if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
 260                 tun->dev->stats.rx_dropped++;
 261                 return -ENOMEM;
 262         }
 263
 264         if (align)
 265                 skb_reserve(skb, align);
 266         if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
 267                 tun->dev->stats.rx_dropped++;
 268                 kfree_skb(skb);
 269                 return -EFAULT;
 270         }
 271
 272         switch (tun->flags & TUN_TYPE_MASK) {
 273         case TUN_TUN_DEV:
 274                 skb_reset_mac_header(skb);
 275                 skb->protocol = pi.proto;
 276                 skb->dev = tun->dev;
 277                 break;
 278         case TUN_TAP_DEV:
 279                 skb->protocol = eth_type_trans(skb, tun->dev);
 280                 break;
 281         };
 282
 283         if (tun->flags & TUN_NOCHECKSUM)
 284                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 285
 286         netif_rx_ni(skb);
 287         tun->dev->last_rx = jiffies;
 288
 289         tun->dev->stats.rx_packets++;
 290         tun->dev->stats.rx_bytes += len;
 291
 292         return count;
 293 }
 294
 295 static inline size_t iov_total(const struct iovec *iv, unsigned long count)
 296 {
 297         unsigned long i;
 298         size_t len;
 299
 300         for (i = 0, len = 0; i < count; i++)
 301                 len += iv[i].iov_len;
 302
 303         return len;
 304 }
 305
 306 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 307                               unsigned long count, loff_t pos)
 308 {
 309         struct tun_struct *tun = iocb->ki_filp->private_data;
 310
 311         if (!tun)
 312                 return -EBADFD;
 313
 314         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 315
 316         return tun_get_user(tun, (struct iovec *) iv, iov_total(iv, count));
 317 }
 318
 319 /* Put packet to the user space buffer */
 320 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 321                                        struct sk_buff *skb,
 322                                        struct iovec *iv, int len)
 323 {
 324         struct tun_pi pi = { 0, skb->protocol };
 325         ssize_t total = 0;
 326
 327         if (!(tun->flags & TUN_NO_PI)) {
 328                 if ((len -= sizeof(pi)) < 0)
 329                         return -EINVAL;
 330
 331                 if (len < skb->len) {
 332                         /* Packet will be striped */
 333                         pi.flags |= TUN_PKT_STRIP;
 334                 }
 335
 336                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 337                         return -EFAULT;
 338                 total += sizeof(pi);
 339         }
 340
 341         len = min_t(int, skb->len, len);
 342
 343         skb_copy_datagram_iovec(skb, 0, iv, len);
 344         total += len;
 345
 346         tun->dev->stats.tx_packets++;
 347         tun->dev->stats.tx_bytes += len;
 348
 349         return total;
 350 }
 351
 352 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 353                             unsigned long count, loff_t pos)
 354 {
 355         struct file *file = iocb->ki_filp;
 356         struct tun_struct *tun = file->private_data;
 357         DECLARE_WAITQUEUE(wait, current);
 358         struct sk_buff *skb;
 359         ssize_t len, ret = 0;
 360         DECLARE_MAC_BUF(mac);
 361
 362         if (!tun)
 363                 return -EBADFD;
 364
 365         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 366
 367         len = iov_total(iv, count);
 368         if (len < 0)
 369                 return -EINVAL;
 370
 371         add_wait_queue(&tun->read_wait, &wait);
 372         while (len) {
 373                 const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 374                 u8 addr[ ETH_ALEN];
 375                 int bit_nr;
 376
 377                 current->state = TASK_INTERRUPTIBLE;
 378
 379                 /* Read frames from the queue */
 380                 if (!(skb=skb_dequeue(&tun->readq))) {
 381                         if (file->f_flags & O_NONBLOCK) {
 382                                 ret = -EAGAIN;
 383                                 break;
 384                         }
 385                         if (signal_pending(current)) {
 386                                 ret = -ERESTARTSYS;
 387                                 break;
 388                         }
 389
 390                         /* Nothing to read, let's sleep */
 391                         schedule();
 392                         continue;
 393                 }
 394                 netif_wake_queue(tun->dev);
 395
 396                 /** Decide whether to accept this packet. This code is designed to
 397                  * behave identically to an Ethernet interface. Accept the packet if
 398                  * - we are promiscuous.
 399                  * - the packet is addressed to us.
 400                  * - the packet is broadcast.
 401                  * - the packet is multicast and
 402                  *   - we are multicast promiscous.
 403                  *   - we belong to the multicast group.
 404                  */
 405                 skb_copy_from_linear_data(skb, addr, min_t(size_t, sizeof addr,
 406                                                                    skb->len));
 407                 bit_nr = ether_crc(sizeof addr, addr) >> 26;
 408                 if ((tun->if_flags & IFF_PROMISC) ||
 409                                 memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
 410                                 memcmp(addr, ones, sizeof addr) == 0 ||
 411                                 (((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
 412                                   (addr[0] == 0x33 && addr[1] == 0x33)) &&
 413                                  ((tun->if_flags & IFF_ALLMULTI) ||
 414                                   (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
 415                         DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %s\n",
 416                                         tun->dev->name, print_mac(mac, addr));
 417                         ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 418                         kfree_skb(skb);
 419                         break;
 420                 } else {
 421                         DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n",
 422                                         tun->dev->name, print_mac(mac, addr));
 423                         kfree_skb(skb);
 424                         continue;
 425                 }
 426         }
 427
 428         current->state = TASK_RUNNING;
 429         remove_wait_queue(&tun->read_wait, &wait);
 430
 431         return ret;
 432 }
 433
 434 static void tun_setup(struct net_device *dev)
 435 {
 436         struct tun_struct *tun = netdev_priv(dev);
 437
 438         skb_queue_head_init(&tun->readq);
 439         init_waitqueue_head(&tun->read_wait);
 440
 441         tun->owner = -1;
 442         tun->group = -1;
 443
 444         dev->open = tun_net_open;
 445         dev->hard_start_xmit = tun_net_xmit;
 446         dev->stop = tun_net_close;
 447         dev->ethtool_ops = &tun_ethtool_ops;
 448         dev->destructor = free_netdev;
 449 }
 450
 451 static struct tun_struct *tun_get_by_name(const char *name)
 452 {
 453         struct tun_struct *tun;
 454
 455         ASSERT_RTNL();
 456         list_for_each_entry(tun, &tun_dev_list, list) {
 457                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
 458                     return tun;
 459         }
 460
 461         return NULL;
 462 }
 463
 464 static int tun_set_iff(struct file *file, struct ifreq *ifr)
 465 {
 466         struct tun_struct *tun;
 467         struct net_device *dev;
 468         int err;
 469
 470         tun = tun_get_by_name(ifr->ifr_name);
 471         if (tun) {
 472                 if (tun->attached)
 473                         return -EBUSY;
 474
 475                 /* Check permissions */
 476                 if (((tun->owner != -1 &&
 477                       current->euid != tun->owner) ||
 478                      (tun->group != -1 &&
 479                       current->egid != tun->group)) &&
 480                      !capable(CAP_NET_ADMIN))
 481                         return -EPERM;
 482         }
 483         else if (__dev_get_by_name(&init_net, ifr->ifr_name))
 484                 return -EINVAL;
 485         else {
 486                 char *name;
 487                 unsigned long flags = 0;
 488
 489                 err = -EINVAL;
 490
 491                 if (!capable(CAP_NET_ADMIN))
 492                         return -EPERM;
 493
 494                 /* Set dev type */
 495                 if (ifr->ifr_flags & IFF_TUN) {
 496                         /* TUN device */
 497                         flags |= TUN_TUN_DEV;
 498                         name = "tun%d";
 499                 } else if (ifr->ifr_flags & IFF_TAP) {
 500                         /* TAP device */
 501                         flags |= TUN_TAP_DEV;
 502                         name = "tap%d";
 503                 } else
 504                         goto failed;
 505
 506                 if (*ifr->ifr_name)
 507                         name = ifr->ifr_name;
 508
 509                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 510                                    tun_setup);
 511                 if (!dev)
 512                         return -ENOMEM;
 513
 514                 tun = netdev_priv(dev);
 515                 tun->dev = dev;
 516                 tun->flags = flags;
 517                 /* Be promiscuous by default to maintain previous behaviour. */
 518                 tun->if_flags = IFF_PROMISC;
 519                 /* Generate random Ethernet address. */
 520                 *(u16 *)tun->dev_addr = htons(0x00FF);
 521                 get_random_bytes(tun->dev_addr + sizeof(u16), 4);
 522                 memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 523
 524                 tun_net_init(dev);
 525
 526                 if (strchr(dev->name, '%')) {
 527                         err = dev_alloc_name(dev, dev->name);
 528                         if (err < 0)
 529                                 goto err_free_dev;
 530                 }
 531
 532                 err = register_netdevice(tun->dev);
 533                 if (err < 0)
 534                         goto err_free_dev;
 535
 536                 list_add(&tun->list, &tun_dev_list);
 537         }
 538
 539         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 540
 541         if (ifr->ifr_flags & IFF_NO_PI)
 542                 tun->flags |= TUN_NO_PI;
 543
 544         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 545                 tun->flags |= TUN_ONE_QUEUE;
 546
 547         file->private_data = tun;
 548         tun->attached = 1;
 549
 550         strcpy(ifr->ifr_name, tun->dev->name);
 551         return 0;
 552
 553  err_free_dev:
 554         free_netdev(dev);
 555  failed:
 556         return err;
 557 }
 558
 559 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 560                          unsigned int cmd, unsigned long arg)
 561 {
 562         struct tun_struct *tun = file->private_data;
 563         void __user* argp = (void __user*)arg;
 564         struct ifreq ifr;
 565         DECLARE_MAC_BUF(mac);
 566
 567         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 568                 if (copy_from_user(&ifr, argp, sizeof ifr))
 569                         return -EFAULT;
 570
 571         if (cmd == TUNSETIFF && !tun) {
 572                 int err;
 573
 574                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 575
 576                 rtnl_lock();
 577                 err = tun_set_iff(file, &ifr);
 578                 rtnl_unlock();
 579
 580                 if (err)
 581                         return err;
 582
 583                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 584                         return -EFAULT;
 585                 return 0;
 586         }
 587
 588         if (!tun)
 589                 return -EBADFD;
 590
 591         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 592
 593         switch (cmd) {
 594         case TUNSETNOCSUM:
 595                 /* Disable/Enable checksum */
 596                 if (arg)
 597                         tun->flags |= TUN_NOCHECKSUM;
 598                 else
 599                         tun->flags &= ~TUN_NOCHECKSUM;
 600
 601                 DBG(KERN_INFO "%s: checksum %s\n",
 602                     tun->dev->name, arg ? "disabled" : "enabled");
 603                 break;
 604
 605         case TUNSETPERSIST:
 606                 /* Disable/Enable persist mode */
 607                 if (arg)
 608                         tun->flags |= TUN_PERSIST;
 609                 else
 610                         tun->flags &= ~TUN_PERSIST;
 611
 612                 DBG(KERN_INFO "%s: persist %s\n",
 613                     tun->dev->name, arg ? "disabled" : "enabled");
 614                 break;
 615
 616         case TUNSETOWNER:
 617                 /* Set owner of the device */
 618                 tun->owner = (uid_t) arg;
 619
 620                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 621                 break;
 622
 623         case TUNSETGROUP:
 624                 /* Set group of the device */
 625                 tun->group= (gid_t) arg;
 626
 627                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 628                 break;
 629
 630         case TUNSETLINK:
 631                 /* Only allow setting the type when the interface is down */
 632                 if (tun->dev->flags & IFF_UP) {
 633                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 634                                 tun->dev->name);
 635                         return -EBUSY;
 636                 } else {
 637                         tun->dev->type = (int) arg;
 638                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 639                 }
 640                 break;
 641
 642 #ifdef TUN_DEBUG
 643         case TUNSETDEBUG:
 644                 tun->debug = arg;
 645                 break;
 646 #endif
 647
 648         case SIOCGIFFLAGS:
 649                 ifr.ifr_flags = tun->if_flags;
 650                 if (copy_to_user( argp, &ifr, sizeof ifr))
 651                         return -EFAULT;
 652                 return 0;
 653
 654         case SIOCSIFFLAGS:
 655                 /** Set the character device's interface flags. Currently only
 656                  * IFF_PROMISC and IFF_ALLMULTI are used. */
 657                 tun->if_flags = ifr.ifr_flags;
 658                 DBG(KERN_INFO "%s: interface flags 0x%lx\n",
 659                                 tun->dev->name, tun->if_flags);
 660                 return 0;
 661
 662         case SIOCGIFHWADDR:
 663                 /* Note: the actual net device's address may be different */
 664                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
 665                                 min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 666                 if (copy_to_user( argp, &ifr, sizeof ifr))
 667                         return -EFAULT;
 668                 return 0;
 669
 670         case SIOCSIFHWADDR:
 671         {
 672                 /* try to set the actual net device's hw address */
 673                 int ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
 674
 675                 if (ret == 0) {
 676                         /** Set the character device's hardware address. This is used when
 677                          * filtering packets being sent from the network device to the character
 678                          * device. */
 679                         memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
 680                                         min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 681                         DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
 682                                         tun->dev->name,
 683                                         tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
 684                                         tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
 685                 }
 686
 687                 return  ret;
 688         }
 689
 690         case SIOCADDMULTI:
 691                 /** Add the specified group to the character device's multicast filter
 692                  * list. */
 693                 add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 694                 DBG(KERN_DEBUG "%s: add multi: %s\n",
 695                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 696                 return 0;
 697
 698         case SIOCDELMULTI:
 699                 /** Remove the specified group from the character device's multicast
 700                  * filter list. */
 701                 del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 702                 DBG(KERN_DEBUG "%s: del multi: %s\n",
 703                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 704                 return 0;
 705
 706         default:
 707                 return -EINVAL;
 708         };
 709
 710         return 0;
 711 }
 712
 713 static int tun_chr_fasync(int fd, struct file *file, int on)
 714 {
 715         struct tun_struct *tun = file->private_data;
 716         int ret;
 717
 718         if (!tun)
 719                 return -EBADFD;
 720
 721         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 722
 723         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
 724                 return ret;
 725
 726         if (on) {
 727                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
 728                 if (ret)
 729                         return ret;
 730                 tun->flags |= TUN_FASYNC;
 731         } else
 732                 tun->flags &= ~TUN_FASYNC;
 733
 734         return 0;
 735 }
 736
 737 static int tun_chr_open(struct inode *inode, struct file * file)
 738 {
 739         DBG1(KERN_INFO "tunX: tun_chr_open\n");
 740         file->private_data = NULL;
 741         return 0;
 742 }
 743
 744 static int tun_chr_close(struct inode *inode, struct file *file)
 745 {
 746         struct tun_struct *tun = file->private_data;
 747
 748         if (!tun)
 749                 return 0;
 750
 751         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 752
 753         tun_chr_fasync(-1, file, 0);
 754
 755         rtnl_lock();
 756
 757         /* Detach from net device */
 758         file->private_data = NULL;
 759         tun->attached = 0;
 760
 761         /* Drop read queue */
 762         skb_queue_purge(&tun->readq);
 763
 764         if (!(tun->flags & TUN_PERSIST)) {
 765                 list_del(&tun->list);
 766                 unregister_netdevice(tun->dev);
 767         }
 768
 769         rtnl_unlock();
 770
 771         return 0;
 772 }
 773
 774 static const struct file_operations tun_fops = {
 775         .owner  = THIS_MODULE,
 776         .llseek = no_llseek,
 777         .read  = do_sync_read,
 778         .aio_read  = tun_chr_aio_read,
 779         .write = do_sync_write,
 780         .aio_write = tun_chr_aio_write,
 781         .poll   = tun_chr_poll,
 782         .ioctl  = tun_chr_ioctl,
 783         .open   = tun_chr_open,
 784         .release = tun_chr_close,
 785         .fasync = tun_chr_fasync
 786 };
 787
 788 static struct miscdevice tun_miscdev = {
 789         .minor = TUN_MINOR,
 790         .name = "tun",
 791         .fops = &tun_fops,
 792 };
 793
 794 /* ethtool interface */
 795
 796 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 797 {
 798         cmd->supported          = 0;
 799         cmd->advertising        = 0;
 800         cmd->speed              = SPEED_10;
 801         cmd->duplex             = DUPLEX_FULL;
 802         cmd->port               = PORT_TP;
 803         cmd->phy_address        = 0;
 804         cmd->transceiver        = XCVR_INTERNAL;
 805         cmd->autoneg            = AUTONEG_DISABLE;
 806         cmd->maxtxpkt           = 0;
 807         cmd->maxrxpkt           = 0;
 808         return 0;
 809 }
 810
 811 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 812 {
 813         struct tun_struct *tun = netdev_priv(dev);
 814
 815         strcpy(info->driver, DRV_NAME);
 816         strcpy(info->version, DRV_VERSION);
 817         strcpy(info->fw_version, "N/A");
 818
 819         switch (tun->flags & TUN_TYPE_MASK) {
 820         case TUN_TUN_DEV:
 821                 strcpy(info->bus_info, "tun");
 822                 break;
 823         case TUN_TAP_DEV:
 824                 strcpy(info->bus_info, "tap");
 825                 break;
 826         }
 827 }
 828
 829 static u32 tun_get_msglevel(struct net_device *dev)
 830 {
 831 #ifdef TUN_DEBUG
 832         struct tun_struct *tun = netdev_priv(dev);
 833         return tun->debug;
 834 #else
 835         return -EOPNOTSUPP;
 836 #endif
 837 }
 838
 839 static void tun_set_msglevel(struct net_device *dev, u32 value)
 840 {
 841 #ifdef TUN_DEBUG
 842         struct tun_struct *tun = netdev_priv(dev);
 843         tun->debug = value;
 844 #endif
 845 }
 846
 847 static u32 tun_get_link(struct net_device *dev)
 848 {
 849         struct tun_struct *tun = netdev_priv(dev);
 850         return tun->attached;
 851 }
 852
 853 static u32 tun_get_rx_csum(struct net_device *dev)
 854 {
 855         struct tun_struct *tun = netdev_priv(dev);
 856         return (tun->flags & TUN_NOCHECKSUM) == 0;
 857 }
 858
 859 static int tun_set_rx_csum(struct net_device *dev, u32 data)
 860 {
 861         struct tun_struct *tun = netdev_priv(dev);
 862         if (data)
 863                 tun->flags &= ~TUN_NOCHECKSUM;
 864         else
 865                 tun->flags |= TUN_NOCHECKSUM;
 866         return 0;
 867 }
 868
 869 static const struct ethtool_ops tun_ethtool_ops = {
 870         .get_settings   = tun_get_settings,
 871         .get_drvinfo    = tun_get_drvinfo,
 872         .get_msglevel   = tun_get_msglevel,
 873         .set_msglevel   = tun_set_msglevel,
 874         .get_link       = tun_get_link,
 875         .get_rx_csum    = tun_get_rx_csum,
 876         .set_rx_csum    = tun_set_rx_csum
 877 };
 878
 879 static int __init tun_init(void)
 880 {
 881         int ret = 0;
 882
 883         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
 884         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
 885
 886         ret = misc_register(&tun_miscdev);
 887         if (ret)
 888                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
 889         return ret;
 890 }
 891
 892 static void tun_cleanup(void)
 893 {
 894         struct tun_struct *tun, *nxt;
 895
 896         misc_deregister(&tun_miscdev);
 897
 898         rtnl_lock();
 899         list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
 900                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
 901                 unregister_netdevice(tun->dev);
 902         }
 903         rtnl_unlock();
 904
 905 }
 906
 907 module_init(tun_init);
 908 module_exit(tun_cleanup);
 909 MODULE_DESCRIPTION(DRV_DESCRIPTION);
 910 MODULE_AUTHOR(DRV_COPYRIGHT);
 911 MODULE_LICENSE("GPL");
 912 MODULE_ALIAS_MISCDEV(TUN_MINOR);