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 #include <net/netns/generic.h>
  67
  68 #include <asm/system.h>
  69 #include <asm/uaccess.h>
  70
  71 /* Uncomment to enable debugging */
  72 /* #define TUN_DEBUG 1 */
  73
  74 #ifdef TUN_DEBUG
  75 static int debug;
  76
  77 #define DBG  if(tun->debug)printk
  78 #define DBG1 if(debug==2)printk
  79 #else
  80 #define DBG( a... )
  81 #define DBG1( a... )
  82 #endif
  83
  84 struct tun_struct {
  85         struct list_head        list;
  86         unsigned long           flags;
  87         int                     attached;
  88         uid_t                   owner;
  89         gid_t                   group;
  90
  91         wait_queue_head_t       read_wait;
  92         struct sk_buff_head     readq;
  93
  94         struct net_device       *dev;
  95
  96         struct fasync_struct    *fasync;
  97
  98         unsigned long if_flags;
  99         u8 dev_addr[ETH_ALEN];
 100         u32 chr_filter[2];
 101         u32 net_filter[2];
 102
 103 #ifdef TUN_DEBUG
 104         int debug;
 105 #endif
 106 };
 107
 108 /* Network device part of the driver */
 109
 110 static unsigned int tun_net_id;
 111 struct tun_net {
 112         struct list_head dev_list;
 113 };
 114
 115 static LIST_HEAD(tun_dev_list);
 116 static const struct ethtool_ops tun_ethtool_ops;
 117
 118 /* Net device open. */
 119 static int tun_net_open(struct net_device *dev)
 120 {
 121         netif_start_queue(dev);
 122         return 0;
 123 }
 124
 125 /* Net device close. */
 126 static int tun_net_close(struct net_device *dev)
 127 {
 128         netif_stop_queue(dev);
 129         return 0;
 130 }
 131
 132 /* Net device start xmit */
 133 static int tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 134 {
 135         struct tun_struct *tun = netdev_priv(dev);
 136
 137         DBG(KERN_INFO "%s: tun_net_xmit %d\n", tun->dev->name, skb->len);
 138
 139         /* Drop packet if interface is not attached */
 140         if (!tun->attached)
 141                 goto drop;
 142
 143         /* Packet dropping */
 144         if (skb_queue_len(&tun->readq) >= dev->tx_queue_len) {
 145                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 146                         /* Normal queueing mode. */
 147                         /* Packet scheduler handles dropping of further packets. */
 148                         netif_stop_queue(dev);
 149
 150                         /* We won't see all dropped packets individually, so overrun
 151                          * error is more appropriate. */
 152                         dev->stats.tx_fifo_errors++;
 153                 } else {
 154                         /* Single queue mode.
 155                          * Driver handles dropping of all packets itself. */
 156                         goto drop;
 157                 }
 158         }
 159
 160         /* Queue packet */
 161         skb_queue_tail(&tun->readq, skb);
 162         dev->trans_start = jiffies;
 163
 164         /* Notify and wake up reader process */
 165         if (tun->flags & TUN_FASYNC)
 166                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 167         wake_up_interruptible(&tun->read_wait);
 168         return 0;
 169
 170 drop:
 171         dev->stats.tx_dropped++;
 172         kfree_skb(skb);
 173         return 0;
 174 }
 175
 176 /** Add the specified Ethernet address to this multicast filter. */
 177 static void
 178 add_multi(u32* filter, const u8* addr)
 179 {
 180         int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
 181         filter[bit_nr >> 5] |= 1 << (bit_nr & 31);
 182 }
 183
 184 /** Remove the specified Ethernet addres from this multicast filter. */
 185 static void
 186 del_multi(u32* filter, const u8* addr)
 187 {
 188         int bit_nr = ether_crc(ETH_ALEN, addr) >> 26;
 189         filter[bit_nr >> 5] &= ~(1 << (bit_nr & 31));
 190 }
 191
 192 /** Update the list of multicast groups to which the network device belongs.
 193  * This list is used to filter packets being sent from the character device to
 194  * the network device. */
 195 static void
 196 tun_net_mclist(struct net_device *dev)
 197 {
 198         struct tun_struct *tun = netdev_priv(dev);
 199         const struct dev_mc_list *mclist;
 200         int i;
 201         DECLARE_MAC_BUF(mac);
 202         DBG(KERN_DEBUG "%s: tun_net_mclist: mc_count %d\n",
 203                         dev->name, dev->mc_count);
 204         memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 205         for (i = 0, mclist = dev->mc_list; i < dev->mc_count && mclist != NULL;
 206                         i++, mclist = mclist->next) {
 207                 add_multi(tun->net_filter, mclist->dmi_addr);
 208                 DBG(KERN_DEBUG "%s: tun_net_mclist: %s\n",
 209                     dev->name, print_mac(mac, mclist->dmi_addr));
 210         }
 211 }
 212
 213 #define MIN_MTU 68
 214 #define MAX_MTU 65535
 215
 216 static int
 217 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 218 {
 219         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 220                 return -EINVAL;
 221         dev->mtu = new_mtu;
 222         return 0;
 223 }
 224
 225 /* Initialize net device. */
 226 static void tun_net_init(struct net_device *dev)
 227 {
 228         struct tun_struct *tun = netdev_priv(dev);
 229
 230         switch (tun->flags & TUN_TYPE_MASK) {
 231         case TUN_TUN_DEV:
 232                 /* Point-to-Point TUN Device */
 233                 dev->hard_header_len = 0;
 234                 dev->addr_len = 0;
 235                 dev->mtu = 1500;
 236                 dev->change_mtu = tun_net_change_mtu;
 237
 238                 /* Zero header length */
 239                 dev->type = ARPHRD_NONE;
 240                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 241                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 242                 break;
 243
 244         case TUN_TAP_DEV:
 245                 /* Ethernet TAP Device */
 246                 dev->set_multicast_list = tun_net_mclist;
 247
 248                 ether_setup(dev);
 249                 dev->change_mtu = tun_net_change_mtu;
 250
 251                 /* random address already created for us by tun_set_iff, use it */
 252                 memcpy(dev->dev_addr, tun->dev_addr, min(sizeof(tun->dev_addr), sizeof(dev->dev_addr)) );
 253
 254                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 255                 break;
 256         }
 257 }
 258
 259 /* Character device part */
 260
 261 /* Poll */
 262 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 263 {
 264         struct tun_struct *tun = file->private_data;
 265         unsigned int mask = POLLOUT | POLLWRNORM;
 266
 267         if (!tun)
 268                 return -EBADFD;
 269
 270         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 271
 272         poll_wait(file, &tun->read_wait, wait);
 273
 274         if (!skb_queue_empty(&tun->readq))
 275                 mask |= POLLIN | POLLRDNORM;
 276
 277         return mask;
 278 }
 279
 280 /* Get packet from user space buffer */
 281 static __inline__ ssize_t tun_get_user(struct tun_struct *tun, struct iovec *iv, size_t count)
 282 {
 283         struct tun_pi pi = { 0, __constant_htons(ETH_P_IP) };
 284         struct sk_buff *skb;
 285         size_t len = count, align = 0;
 286
 287         if (!(tun->flags & TUN_NO_PI)) {
 288                 if ((len -= sizeof(pi)) > count)
 289                         return -EINVAL;
 290
 291                 if(memcpy_fromiovec((void *)&pi, iv, sizeof(pi)))
 292                         return -EFAULT;
 293         }
 294
 295         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 296                 align = NET_IP_ALIGN;
 297                 if (unlikely(len < ETH_HLEN))
 298                         return -EINVAL;
 299         }
 300
 301         if (!(skb = alloc_skb(len + align, GFP_KERNEL))) {
 302                 tun->dev->stats.rx_dropped++;
 303                 return -ENOMEM;
 304         }
 305
 306         if (align)
 307                 skb_reserve(skb, align);
 308         if (memcpy_fromiovec(skb_put(skb, len), iv, len)) {
 309                 tun->dev->stats.rx_dropped++;
 310                 kfree_skb(skb);
 311                 return -EFAULT;
 312         }
 313
 314         switch (tun->flags & TUN_TYPE_MASK) {
 315         case TUN_TUN_DEV:
 316                 skb_reset_mac_header(skb);
 317                 skb->protocol = pi.proto;
 318                 skb->dev = tun->dev;
 319                 break;
 320         case TUN_TAP_DEV:
 321                 skb->protocol = eth_type_trans(skb, tun->dev);
 322                 break;
 323         };
 324
 325         if (tun->flags & TUN_NOCHECKSUM)
 326                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 327
 328         netif_rx_ni(skb);
 329         tun->dev->last_rx = jiffies;
 330
 331         tun->dev->stats.rx_packets++;
 332         tun->dev->stats.rx_bytes += len;
 333
 334         return count;
 335 }
 336
 337 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 338                               unsigned long count, loff_t pos)
 339 {
 340         struct tun_struct *tun = iocb->ki_filp->private_data;
 341
 342         if (!tun)
 343                 return -EBADFD;
 344
 345         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 346
 347         return tun_get_user(tun, (struct iovec *) iv, iov_length(iv, count));
 348 }
 349
 350 /* Put packet to the user space buffer */
 351 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 352                                        struct sk_buff *skb,
 353                                        struct iovec *iv, int len)
 354 {
 355         struct tun_pi pi = { 0, skb->protocol };
 356         ssize_t total = 0;
 357
 358         if (!(tun->flags & TUN_NO_PI)) {
 359                 if ((len -= sizeof(pi)) < 0)
 360                         return -EINVAL;
 361
 362                 if (len < skb->len) {
 363                         /* Packet will be striped */
 364                         pi.flags |= TUN_PKT_STRIP;
 365                 }
 366
 367                 if (memcpy_toiovec(iv, (void *) &pi, sizeof(pi)))
 368                         return -EFAULT;
 369                 total += sizeof(pi);
 370         }
 371
 372         len = min_t(int, skb->len, len);
 373
 374         skb_copy_datagram_iovec(skb, 0, iv, len);
 375         total += len;
 376
 377         tun->dev->stats.tx_packets++;
 378         tun->dev->stats.tx_bytes += len;
 379
 380         return total;
 381 }
 382
 383 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 384                             unsigned long count, loff_t pos)
 385 {
 386         struct file *file = iocb->ki_filp;
 387         struct tun_struct *tun = file->private_data;
 388         DECLARE_WAITQUEUE(wait, current);
 389         struct sk_buff *skb;
 390         ssize_t len, ret = 0;
 391         DECLARE_MAC_BUF(mac);
 392
 393         if (!tun)
 394                 return -EBADFD;
 395
 396         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 397
 398         len = iov_length(iv, count);
 399         if (len < 0)
 400                 return -EINVAL;
 401
 402         add_wait_queue(&tun->read_wait, &wait);
 403         while (len) {
 404                 const u8 ones[ ETH_ALEN] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 405                 u8 addr[ ETH_ALEN];
 406                 int bit_nr;
 407
 408                 current->state = TASK_INTERRUPTIBLE;
 409
 410                 /* Read frames from the queue */
 411                 if (!(skb=skb_dequeue(&tun->readq))) {
 412                         if (file->f_flags & O_NONBLOCK) {
 413                                 ret = -EAGAIN;
 414                                 break;
 415                         }
 416                         if (signal_pending(current)) {
 417                                 ret = -ERESTARTSYS;
 418                                 break;
 419                         }
 420
 421                         /* Nothing to read, let's sleep */
 422                         schedule();
 423                         continue;
 424                 }
 425                 netif_wake_queue(tun->dev);
 426
 427                 /** Decide whether to accept this packet. This code is designed to
 428                  * behave identically to an Ethernet interface. Accept the packet if
 429                  * - we are promiscuous.
 430                  * - the packet is addressed to us.
 431                  * - the packet is broadcast.
 432                  * - the packet is multicast and
 433                  *   - we are multicast promiscous.
 434                  *   - we belong to the multicast group.
 435                  */
 436                 skb_copy_from_linear_data(skb, addr, min_t(size_t, sizeof addr,
 437                                                                    skb->len));
 438                 bit_nr = ether_crc(sizeof addr, addr) >> 26;
 439                 if ((tun->if_flags & IFF_PROMISC) ||
 440                                 memcmp(addr, tun->dev_addr, sizeof addr) == 0 ||
 441                                 memcmp(addr, ones, sizeof addr) == 0 ||
 442                                 (((addr[0] == 1 && addr[1] == 0 && addr[2] == 0x5e) ||
 443                                   (addr[0] == 0x33 && addr[1] == 0x33)) &&
 444                                  ((tun->if_flags & IFF_ALLMULTI) ||
 445                                   (tun->chr_filter[bit_nr >> 5] & (1 << (bit_nr & 31)))))) {
 446                         DBG(KERN_DEBUG "%s: tun_chr_readv: accepted: %s\n",
 447                                         tun->dev->name, print_mac(mac, addr));
 448                         ret = tun_put_user(tun, skb, (struct iovec *) iv, len);
 449                         kfree_skb(skb);
 450                         break;
 451                 } else {
 452                         DBG(KERN_DEBUG "%s: tun_chr_readv: rejected: %s\n",
 453                                         tun->dev->name, print_mac(mac, addr));
 454                         kfree_skb(skb);
 455                         continue;
 456                 }
 457         }
 458
 459         current->state = TASK_RUNNING;
 460         remove_wait_queue(&tun->read_wait, &wait);
 461
 462         return ret;
 463 }
 464
 465 static void tun_setup(struct net_device *dev)
 466 {
 467         struct tun_struct *tun = netdev_priv(dev);
 468
 469         skb_queue_head_init(&tun->readq);
 470         init_waitqueue_head(&tun->read_wait);
 471
 472         tun->owner = -1;
 473         tun->group = -1;
 474
 475         dev->open = tun_net_open;
 476         dev->hard_start_xmit = tun_net_xmit;
 477         dev->stop = tun_net_close;
 478         dev->ethtool_ops = &tun_ethtool_ops;
 479         dev->destructor = free_netdev;
 480 }
 481
 482 static struct tun_struct *tun_get_by_name(const char *name)
 483 {
 484         struct tun_struct *tun;
 485
 486         ASSERT_RTNL();
 487         list_for_each_entry(tun, &tun_dev_list, list) {
 488                 if (!strncmp(tun->dev->name, name, IFNAMSIZ))
 489                     return tun;
 490         }
 491
 492         return NULL;
 493 }
 494
 495 static int tun_set_iff(struct file *file, struct ifreq *ifr)
 496 {
 497         struct tun_struct *tun;
 498         struct net_device *dev;
 499         int err;
 500
 501         tun = tun_get_by_name(ifr->ifr_name);
 502         if (tun) {
 503                 if (tun->attached)
 504                         return -EBUSY;
 505
 506                 /* Check permissions */
 507                 if (((tun->owner != -1 &&
 508                       current->euid != tun->owner) ||
 509                      (tun->group != -1 &&
 510                       current->egid != tun->group)) &&
 511                      !capable(CAP_NET_ADMIN))
 512                         return -EPERM;
 513         }
 514         else if (__dev_get_by_name(&init_net, ifr->ifr_name))
 515                 return -EINVAL;
 516         else {
 517                 char *name;
 518                 unsigned long flags = 0;
 519
 520                 err = -EINVAL;
 521
 522                 if (!capable(CAP_NET_ADMIN))
 523                         return -EPERM;
 524
 525                 /* Set dev type */
 526                 if (ifr->ifr_flags & IFF_TUN) {
 527                         /* TUN device */
 528                         flags |= TUN_TUN_DEV;
 529                         name = "tun%d";
 530                 } else if (ifr->ifr_flags & IFF_TAP) {
 531                         /* TAP device */
 532                         flags |= TUN_TAP_DEV;
 533                         name = "tap%d";
 534                 } else
 535                         goto failed;
 536
 537                 if (*ifr->ifr_name)
 538                         name = ifr->ifr_name;
 539
 540                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 541                                    tun_setup);
 542                 if (!dev)
 543                         return -ENOMEM;
 544
 545                 tun = netdev_priv(dev);
 546                 tun->dev = dev;
 547                 tun->flags = flags;
 548                 /* Be promiscuous by default to maintain previous behaviour. */
 549                 tun->if_flags = IFF_PROMISC;
 550                 /* Generate random Ethernet address. */
 551                 *(__be16 *)tun->dev_addr = htons(0x00FF);
 552                 get_random_bytes(tun->dev_addr + sizeof(u16), 4);
 553                 memset(tun->chr_filter, 0, sizeof tun->chr_filter);
 554
 555                 tun_net_init(dev);
 556
 557                 if (strchr(dev->name, '%')) {
 558                         err = dev_alloc_name(dev, dev->name);
 559                         if (err < 0)
 560                                 goto err_free_dev;
 561                 }
 562
 563                 err = register_netdevice(tun->dev);
 564                 if (err < 0)
 565                         goto err_free_dev;
 566
 567                 list_add(&tun->list, &tun_dev_list);
 568         }
 569
 570         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 571
 572         if (ifr->ifr_flags & IFF_NO_PI)
 573                 tun->flags |= TUN_NO_PI;
 574         else
 575                 tun->flags &= ~TUN_NO_PI;
 576
 577         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 578                 tun->flags |= TUN_ONE_QUEUE;
 579         else
 580                 tun->flags &= ~TUN_ONE_QUEUE;
 581
 582         file->private_data = tun;
 583         tun->attached = 1;
 584
 585         strcpy(ifr->ifr_name, tun->dev->name);
 586         return 0;
 587
 588  err_free_dev:
 589         free_netdev(dev);
 590  failed:
 591         return err;
 592 }
 593
 594 static int tun_chr_ioctl(struct inode *inode, struct file *file,
 595                          unsigned int cmd, unsigned long arg)
 596 {
 597         struct tun_struct *tun = file->private_data;
 598         void __user* argp = (void __user*)arg;
 599         struct ifreq ifr;
 600         DECLARE_MAC_BUF(mac);
 601
 602         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
 603                 if (copy_from_user(&ifr, argp, sizeof ifr))
 604                         return -EFAULT;
 605
 606         if (cmd == TUNSETIFF && !tun) {
 607                 int err;
 608
 609                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
 610
 611                 rtnl_lock();
 612                 err = tun_set_iff(file, &ifr);
 613                 rtnl_unlock();
 614
 615                 if (err)
 616                         return err;
 617
 618                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
 619                         return -EFAULT;
 620                 return 0;
 621         }
 622
 623         if (!tun)
 624                 return -EBADFD;
 625
 626         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
 627
 628         switch (cmd) {
 629         case TUNSETNOCSUM:
 630                 /* Disable/Enable checksum */
 631                 if (arg)
 632                         tun->flags |= TUN_NOCHECKSUM;
 633                 else
 634                         tun->flags &= ~TUN_NOCHECKSUM;
 635
 636                 DBG(KERN_INFO "%s: checksum %s\n",
 637                     tun->dev->name, arg ? "disabled" : "enabled");
 638                 break;
 639
 640         case TUNSETPERSIST:
 641                 /* Disable/Enable persist mode */
 642                 if (arg)
 643                         tun->flags |= TUN_PERSIST;
 644                 else
 645                         tun->flags &= ~TUN_PERSIST;
 646
 647                 DBG(KERN_INFO "%s: persist %s\n",
 648                     tun->dev->name, arg ? "enabled" : "disabled");
 649                 break;
 650
 651         case TUNSETOWNER:
 652                 /* Set owner of the device */
 653                 tun->owner = (uid_t) arg;
 654
 655                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
 656                 break;
 657
 658         case TUNSETGROUP:
 659                 /* Set group of the device */
 660                 tun->group= (gid_t) arg;
 661
 662                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
 663                 break;
 664
 665         case TUNSETLINK:
 666                 /* Only allow setting the type when the interface is down */
 667                 if (tun->dev->flags & IFF_UP) {
 668                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
 669                                 tun->dev->name);
 670                         return -EBUSY;
 671                 } else {
 672                         tun->dev->type = (int) arg;
 673                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
 674                 }
 675                 break;
 676
 677 #ifdef TUN_DEBUG
 678         case TUNSETDEBUG:
 679                 tun->debug = arg;
 680                 break;
 681 #endif
 682
 683         case SIOCGIFFLAGS:
 684                 ifr.ifr_flags = tun->if_flags;
 685                 if (copy_to_user( argp, &ifr, sizeof ifr))
 686                         return -EFAULT;
 687                 return 0;
 688
 689         case SIOCSIFFLAGS:
 690                 /** Set the character device's interface flags. Currently only
 691                  * IFF_PROMISC and IFF_ALLMULTI are used. */
 692                 tun->if_flags = ifr.ifr_flags;
 693                 DBG(KERN_INFO "%s: interface flags 0x%lx\n",
 694                                 tun->dev->name, tun->if_flags);
 695                 return 0;
 696
 697         case SIOCGIFHWADDR:
 698                 /* Note: the actual net device's address may be different */
 699                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev_addr,
 700                                 min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 701                 if (copy_to_user( argp, &ifr, sizeof ifr))
 702                         return -EFAULT;
 703                 return 0;
 704
 705         case SIOCSIFHWADDR:
 706         {
 707                 /* try to set the actual net device's hw address */
 708                 int ret;
 709
 710                 rtnl_lock();
 711                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
 712                 rtnl_unlock();
 713
 714                 if (ret == 0) {
 715                         /** Set the character device's hardware address. This is used when
 716                          * filtering packets being sent from the network device to the character
 717                          * device. */
 718                         memcpy(tun->dev_addr, ifr.ifr_hwaddr.sa_data,
 719                                         min(sizeof ifr.ifr_hwaddr.sa_data, sizeof tun->dev_addr));
 720                         DBG(KERN_DEBUG "%s: set hardware address: %x:%x:%x:%x:%x:%x\n",
 721                                         tun->dev->name,
 722                                         tun->dev_addr[0], tun->dev_addr[1], tun->dev_addr[2],
 723                                         tun->dev_addr[3], tun->dev_addr[4], tun->dev_addr[5]);
 724                 }
 725
 726                 return  ret;
 727         }
 728
 729         case SIOCADDMULTI:
 730                 /** Add the specified group to the character device's multicast filter
 731                  * list. */
 732                 add_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 733                 DBG(KERN_DEBUG "%s: add multi: %s\n",
 734                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 735                 return 0;
 736
 737         case SIOCDELMULTI:
 738                 /** Remove the specified group from the character device's multicast
 739                  * filter list. */
 740                 del_multi(tun->chr_filter, ifr.ifr_hwaddr.sa_data);
 741                 DBG(KERN_DEBUG "%s: del multi: %s\n",
 742                     tun->dev->name, print_mac(mac, ifr.ifr_hwaddr.sa_data));
 743                 return 0;
 744
 745         default:
 746                 return -EINVAL;
 747         };
 748
 749         return 0;
 750 }
 751
 752 static int tun_chr_fasync(int fd, struct file *file, int on)
 753 {
 754         struct tun_struct *tun = file->private_data;
 755         int ret;
 756
 757         if (!tun)
 758                 return -EBADFD;
 759
 760         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
 761
 762         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
 763                 return ret;
 764
 765         if (on) {
 766                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
 767                 if (ret)
 768                         return ret;
 769                 tun->flags |= TUN_FASYNC;
 770         } else
 771                 tun->flags &= ~TUN_FASYNC;
 772
 773         return 0;
 774 }
 775
 776 static int tun_chr_open(struct inode *inode, struct file * file)
 777 {
 778         DBG1(KERN_INFO "tunX: tun_chr_open\n");
 779         file->private_data = NULL;
 780         return 0;
 781 }
 782
 783 static int tun_chr_close(struct inode *inode, struct file *file)
 784 {
 785         struct tun_struct *tun = file->private_data;
 786
 787         if (!tun)
 788                 return 0;
 789
 790         DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
 791
 792         tun_chr_fasync(-1, file, 0);
 793
 794         rtnl_lock();
 795
 796         /* Detach from net device */
 797         file->private_data = NULL;
 798         tun->attached = 0;
 799
 800         /* Drop read queue */
 801         skb_queue_purge(&tun->readq);
 802
 803         if (!(tun->flags & TUN_PERSIST)) {
 804                 list_del(&tun->list);
 805                 unregister_netdevice(tun->dev);
 806         }
 807
 808         rtnl_unlock();
 809
 810         return 0;
 811 }
 812
 813 static const struct file_operations tun_fops = {
 814         .owner  = THIS_MODULE,
 815         .llseek = no_llseek,
 816         .read  = do_sync_read,
 817         .aio_read  = tun_chr_aio_read,
 818         .write = do_sync_write,
 819         .aio_write = tun_chr_aio_write,
 820         .poll   = tun_chr_poll,
 821         .ioctl  = tun_chr_ioctl,
 822         .open   = tun_chr_open,
 823         .release = tun_chr_close,
 824         .fasync = tun_chr_fasync
 825 };
 826
 827 static struct miscdevice tun_miscdev = {
 828         .minor = TUN_MINOR,
 829         .name = "tun",
 830         .fops = &tun_fops,
 831 };
 832
 833 /* ethtool interface */
 834
 835 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
 836 {
 837         cmd->supported          = 0;
 838         cmd->advertising        = 0;
 839         cmd->speed              = SPEED_10;
 840         cmd->duplex             = DUPLEX_FULL;
 841         cmd->port               = PORT_TP;
 842         cmd->phy_address        = 0;
 843         cmd->transceiver        = XCVR_INTERNAL;
 844         cmd->autoneg            = AUTONEG_DISABLE;
 845         cmd->maxtxpkt           = 0;
 846         cmd->maxrxpkt           = 0;
 847         return 0;
 848 }
 849
 850 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
 851 {
 852         struct tun_struct *tun = netdev_priv(dev);
 853
 854         strcpy(info->driver, DRV_NAME);
 855         strcpy(info->version, DRV_VERSION);
 856         strcpy(info->fw_version, "N/A");
 857
 858         switch (tun->flags & TUN_TYPE_MASK) {
 859         case TUN_TUN_DEV:
 860                 strcpy(info->bus_info, "tun");
 861                 break;
 862         case TUN_TAP_DEV:
 863                 strcpy(info->bus_info, "tap");
 864                 break;
 865         }
 866 }
 867
 868 static u32 tun_get_msglevel(struct net_device *dev)
 869 {
 870 #ifdef TUN_DEBUG
 871         struct tun_struct *tun = netdev_priv(dev);
 872         return tun->debug;
 873 #else
 874         return -EOPNOTSUPP;
 875 #endif
 876 }
 877
 878 static void tun_set_msglevel(struct net_device *dev, u32 value)
 879 {
 880 #ifdef TUN_DEBUG
 881         struct tun_struct *tun = netdev_priv(dev);
 882         tun->debug = value;
 883 #endif
 884 }
 885
 886 static u32 tun_get_link(struct net_device *dev)
 887 {
 888         struct tun_struct *tun = netdev_priv(dev);
 889         return tun->attached;
 890 }
 891
 892 static u32 tun_get_rx_csum(struct net_device *dev)
 893 {
 894         struct tun_struct *tun = netdev_priv(dev);
 895         return (tun->flags & TUN_NOCHECKSUM) == 0;
 896 }
 897
 898 static int tun_set_rx_csum(struct net_device *dev, u32 data)
 899 {
 900         struct tun_struct *tun = netdev_priv(dev);
 901         if (data)
 902                 tun->flags &= ~TUN_NOCHECKSUM;
 903         else
 904                 tun->flags |= TUN_NOCHECKSUM;
 905         return 0;
 906 }
 907
 908 static const struct ethtool_ops tun_ethtool_ops = {
 909         .get_settings   = tun_get_settings,
 910         .get_drvinfo    = tun_get_drvinfo,
 911         .get_msglevel   = tun_get_msglevel,
 912         .set_msglevel   = tun_set_msglevel,
 913         .get_link       = tun_get_link,
 914         .get_rx_csum    = tun_get_rx_csum,
 915         .set_rx_csum    = tun_set_rx_csum
 916 };
 917
 918 static int tun_init_net(struct net *net)
 919 {
 920         struct tun_net *tn;
 921
 922         tn = kmalloc(sizeof(*tn), GFP_KERNEL);
 923         if (tn == NULL)
 924                 return -ENOMEM;
 925
 926         INIT_LIST_HEAD(&tn->dev_list);
 927
 928         if (net_assign_generic(net, tun_net_id, tn)) {
 929                 kfree(tn);
 930                 return -ENOMEM;
 931         }
 932
 933         return 0;
 934 }
 935
 936 static void tun_exit_net(struct net *net)
 937 {
 938         struct tun_net *tn;
 939
 940         tn = net_generic(net, tun_net_id);
 941         kfree(tn);
 942 }
 943
 944 static struct pernet_operations tun_net_ops = {
 945         .init = tun_init_net,
 946         .exit = tun_exit_net,
 947 };
 948
 949 static int __init tun_init(void)
 950 {
 951         int ret = 0;
 952
 953         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
 954         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
 955
 956         ret = register_pernet_gen_device(&tun_net_id, &tun_net_ops);
 957         if (ret) {
 958                 printk(KERN_ERR "tun: Can't register pernet ops\n");
 959                 goto err_pernet;
 960         }
 961
 962         ret = misc_register(&tun_miscdev);
 963         if (ret) {
 964                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
 965                 goto err_misc;
 966         }
 967         return 0;
 968
 969 err_misc:
 970         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
 971 err_pernet:
 972         return ret;
 973 }
 974
 975 static void tun_cleanup(void)
 976 {
 977         struct tun_struct *tun, *nxt;
 978
 979         misc_deregister(&tun_miscdev);
 980
 981         rtnl_lock();
 982         list_for_each_entry_safe(tun, nxt, &tun_dev_list, list) {
 983                 DBG(KERN_INFO "%s cleaned up\n", tun->dev->name);
 984                 unregister_netdevice(tun->dev);
 985         }
 986         rtnl_unlock();
 987
 988         unregister_pernet_gen_device(tun_net_id, &tun_net_ops);
 989 }
 990
 991 module_init(tun_init);
 992 module_exit(tun_cleanup);
 993 MODULE_DESCRIPTION(DRV_DESCRIPTION);
 994 MODULE_AUTHOR(DRV_COPYRIGHT);
 995 MODULE_LICENSE("GPL");
 996 MODULE_ALIAS_MISCDEV(TUN_MINOR);