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  *  Mike Kershaw <dragorn@kismetwireless.net> 2005/08/14
  22  *    Add TUNSETLINK ioctl to set the link encapsulation
  23  *
  24  *  Mark Smith <markzzzsmith@yahoo.com.au>
  25  *    Use random_ether_addr() for tap MAC address.
  26  *
  27  *  Harald Roelle <harald.roelle@ifi.lmu.de>  2004/04/20
  28  *    Fixes in packet dropping, queue length setting and queue wakeup.
  29  *    Increased default tx queue length.
  30  *    Added ethtool API.
  31  *    Minor cleanups
  32  *
  33  *  Daniel Podlejski <underley@underley.eu.org>
  34  *    Modifications for 2.3.99-pre5 kernel.
  35  */
  36
  37 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  38
  39 #define DRV_NAME        "tun"
  40 #define DRV_VERSION     "1.6"
  41 #define DRV_DESCRIPTION "Universal TUN/TAP device driver"
  42 #define DRV_COPYRIGHT   "(C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>"
  43
  44 #include <linux/module.h>
  45 #include <linux/errno.h>
  46 #include <linux/kernel.h>
  47 #include <linux/major.h>
  48 #include <linux/slab.h>
  49 #include <linux/poll.h>
  50 #include <linux/fcntl.h>
  51 #include <linux/init.h>
  52 #include <linux/skbuff.h>
  53 #include <linux/netdevice.h>
  54 #include <linux/etherdevice.h>
  55 #include <linux/miscdevice.h>
  56 #include <linux/ethtool.h>
  57 #include <linux/rtnetlink.h>
  58 #include <linux/compat.h>
  59 #include <linux/if.h>
  60 #include <linux/if_arp.h>
  61 #include <linux/if_ether.h>
  62 #include <linux/if_tun.h>
  63 #include <linux/crc32.h>
  64 #include <linux/nsproxy.h>
  65 #include <linux/virtio_net.h>
  66 #include <linux/rcupdate.h>
  67 #include <net/net_namespace.h>
  68 #include <net/netns/generic.h>
  69 #include <net/rtnetlink.h>
  70 #include <net/sock.h>
  71
  72 #include <asm/uaccess.h>
  73
  74 /* Uncomment to enable debugging */
  75 /* #define TUN_DEBUG 1 */
  76
  77 #ifdef TUN_DEBUG
  78 static int debug;
  79
  80 #define tun_debug(level, tun, fmt, args...)                     \
  81 do {                                                            \
  82         if (tun->debug)                                         \
  83                 netdev_printk(level, tun->dev, fmt, ##args);    \
  84 } while (0)
  85 #define DBG1(level, fmt, args...)                               \
  86 do {                                                            \
  87         if (debug == 2)                                         \
  88                 printk(level fmt, ##args);                      \
  89 } while (0)
  90 #else
  91 #define tun_debug(level, tun, fmt, args...)                     \
  92 do {                                                            \
  93         if (0)                                                  \
  94                 netdev_printk(level, tun->dev, fmt, ##args);    \
  95 } while (0)
  96 #define DBG1(level, fmt, args...)                               \
  97 do {                                                            \
  98         if (0)                                                  \
  99                 printk(level fmt, ##args);                      \
 100 } while (0)
 101 #endif
 102
 103 #define FLT_EXACT_COUNT 8
 104 struct tap_filter {
 105         unsigned int    count;    /* Number of addrs. Zero means disabled */
 106         u32             mask[2];  /* Mask of the hashed addrs */
 107         unsigned char   addr[FLT_EXACT_COUNT][ETH_ALEN];
 108 };
 109
 110 struct tun_file {
 111         atomic_t count;
 112         struct tun_struct *tun;
 113         struct net *net;
 114 };
 115
 116 struct tun_sock;
 117
 118 struct tun_struct {
 119         struct tun_file         *tfile;
 120         unsigned int            flags;
 121         uid_t                   owner;
 122         gid_t                   group;
 123
 124         struct net_device       *dev;
 125         netdev_features_t       set_features;
 126 #define TUN_USER_FEATURES (NETIF_F_HW_CSUM|NETIF_F_TSO_ECN|NETIF_F_TSO| \
 127                           NETIF_F_TSO6|NETIF_F_UFO)
 128         struct fasync_struct    *fasync;
 129
 130         struct tap_filter       txflt;
 131         struct socket           socket;
 132         struct socket_wq        wq;
 133
 134         int                     vnet_hdr_sz;
 135
 136 #ifdef TUN_DEBUG
 137         int debug;
 138 #endif
 139 };
 140
 141 struct tun_sock {
 142         struct sock             sk;
 143         struct tun_struct       *tun;
 144 };
 145
 146 static inline struct tun_sock *tun_sk(struct sock *sk)
 147 {
 148         return container_of(sk, struct tun_sock, sk);
 149 }
 150
 151 static int tun_attach(struct tun_struct *tun, struct file *file)
 152 {
 153         struct tun_file *tfile = file->private_data;
 154         int err;
 155
 156         ASSERT_RTNL();
 157
 158         netif_tx_lock_bh(tun->dev);
 159
 160         err = -EINVAL;
 161         if (tfile->tun)
 162                 goto out;
 163
 164         err = -EBUSY;
 165         if (tun->tfile)
 166                 goto out;
 167
 168         err = 0;
 169         tfile->tun = tun;
 170         tun->tfile = tfile;
 171         tun->socket.file = file;
 172         netif_carrier_on(tun->dev);
 173         dev_hold(tun->dev);
 174         sock_hold(tun->socket.sk);
 175         atomic_inc(&tfile->count);
 176
 177 out:
 178         netif_tx_unlock_bh(tun->dev);
 179         return err;
 180 }
 181
 182 static void __tun_detach(struct tun_struct *tun)
 183 {
 184         /* Detach from net device */
 185         netif_tx_lock_bh(tun->dev);
 186         netif_carrier_off(tun->dev);
 187         tun->tfile = NULL;
 188         tun->socket.file = NULL;
 189         netif_tx_unlock_bh(tun->dev);
 190
 191         /* Drop read queue */
 192         skb_queue_purge(&tun->socket.sk->sk_receive_queue);
 193
 194         /* Drop the extra count on the net device */
 195         dev_put(tun->dev);
 196 }
 197
 198 static void tun_detach(struct tun_struct *tun)
 199 {
 200         rtnl_lock();
 201         __tun_detach(tun);
 202         rtnl_unlock();
 203 }
 204
 205 static struct tun_struct *__tun_get(struct tun_file *tfile)
 206 {
 207         struct tun_struct *tun = NULL;
 208
 209         if (atomic_inc_not_zero(&tfile->count))
 210                 tun = tfile->tun;
 211
 212         return tun;
 213 }
 214
 215 static struct tun_struct *tun_get(struct file *file)
 216 {
 217         return __tun_get(file->private_data);
 218 }
 219
 220 static void tun_put(struct tun_struct *tun)
 221 {
 222         struct tun_file *tfile = tun->tfile;
 223
 224         if (atomic_dec_and_test(&tfile->count))
 225                 tun_detach(tfile->tun);
 226 }
 227
 228 /* TAP filtering */
 229 static void addr_hash_set(u32 *mask, const u8 *addr)
 230 {
 231         int n = ether_crc(ETH_ALEN, addr) >> 26;
 232         mask[n >> 5] |= (1 << (n & 31));
 233 }
 234
 235 static unsigned int addr_hash_test(const u32 *mask, const u8 *addr)
 236 {
 237         int n = ether_crc(ETH_ALEN, addr) >> 26;
 238         return mask[n >> 5] & (1 << (n & 31));
 239 }
 240
 241 static int update_filter(struct tap_filter *filter, void __user *arg)
 242 {
 243         struct { u8 u[ETH_ALEN]; } *addr;
 244         struct tun_filter uf;
 245         int err, alen, n, nexact;
 246
 247         if (copy_from_user(&uf, arg, sizeof(uf)))
 248                 return -EFAULT;
 249
 250         if (!uf.count) {
 251                 /* Disabled */
 252                 filter->count = 0;
 253                 return 0;
 254         }
 255
 256         alen = ETH_ALEN * uf.count;
 257         addr = kmalloc(alen, GFP_KERNEL);
 258         if (!addr)
 259                 return -ENOMEM;
 260
 261         if (copy_from_user(addr, arg + sizeof(uf), alen)) {
 262                 err = -EFAULT;
 263                 goto done;
 264         }
 265
 266         /* The filter is updated without holding any locks. Which is
 267          * perfectly safe. We disable it first and in the worst
 268          * case we'll accept a few undesired packets. */
 269         filter->count = 0;
 270         wmb();
 271
 272         /* Use first set of addresses as an exact filter */
 273         for (n = 0; n < uf.count && n < FLT_EXACT_COUNT; n++)
 274                 memcpy(filter->addr[n], addr[n].u, ETH_ALEN);
 275
 276         nexact = n;
 277
 278         /* Remaining multicast addresses are hashed,
 279          * unicast will leave the filter disabled. */
 280         memset(filter->mask, 0, sizeof(filter->mask));
 281         for (; n < uf.count; n++) {
 282                 if (!is_multicast_ether_addr(addr[n].u)) {
 283                         err = 0; /* no filter */
 284                         goto done;
 285                 }
 286                 addr_hash_set(filter->mask, addr[n].u);
 287         }
 288
 289         /* For ALLMULTI just set the mask to all ones.
 290          * This overrides the mask populated above. */
 291         if ((uf.flags & TUN_FLT_ALLMULTI))
 292                 memset(filter->mask, ~0, sizeof(filter->mask));
 293
 294         /* Now enable the filter */
 295         wmb();
 296         filter->count = nexact;
 297
 298         /* Return the number of exact filters */
 299         err = nexact;
 300
 301 done:
 302         kfree(addr);
 303         return err;
 304 }
 305
 306 /* Returns: 0 - drop, !=0 - accept */
 307 static int run_filter(struct tap_filter *filter, const struct sk_buff *skb)
 308 {
 309         /* Cannot use eth_hdr(skb) here because skb_mac_hdr() is incorrect
 310          * at this point. */
 311         struct ethhdr *eh = (struct ethhdr *) skb->data;
 312         int i;
 313
 314         /* Exact match */
 315         for (i = 0; i < filter->count; i++)
 316                 if (!compare_ether_addr(eh->h_dest, filter->addr[i]))
 317                         return 1;
 318
 319         /* Inexact match (multicast only) */
 320         if (is_multicast_ether_addr(eh->h_dest))
 321                 return addr_hash_test(filter->mask, eh->h_dest);
 322
 323         return 0;
 324 }
 325
 326 /*
 327  * Checks whether the packet is accepted or not.
 328  * Returns: 0 - drop, !=0 - accept
 329  */
 330 static int check_filter(struct tap_filter *filter, const struct sk_buff *skb)
 331 {
 332         if (!filter->count)
 333                 return 1;
 334
 335         return run_filter(filter, skb);
 336 }
 337
 338 /* Network device part of the driver */
 339
 340 static const struct ethtool_ops tun_ethtool_ops;
 341
 342 /* Net device detach from fd. */
 343 static void tun_net_uninit(struct net_device *dev)
 344 {
 345         struct tun_struct *tun = netdev_priv(dev);
 346         struct tun_file *tfile = tun->tfile;
 347
 348         /* Inform the methods they need to stop using the dev.
 349          */
 350         if (tfile) {
 351                 wake_up_all(&tun->wq.wait);
 352                 if (atomic_dec_and_test(&tfile->count))
 353                         __tun_detach(tun);
 354         }
 355 }
 356
 357 static void tun_free_netdev(struct net_device *dev)
 358 {
 359         struct tun_struct *tun = netdev_priv(dev);
 360
 361         sk_release_kernel(tun->socket.sk);
 362 }
 363
 364 /* Net device open. */
 365 static int tun_net_open(struct net_device *dev)
 366 {
 367         netif_start_queue(dev);
 368         return 0;
 369 }
 370
 371 /* Net device close. */
 372 static int tun_net_close(struct net_device *dev)
 373 {
 374         netif_stop_queue(dev);
 375         return 0;
 376 }
 377
 378 /* Net device start xmit */
 379 static netdev_tx_t tun_net_xmit(struct sk_buff *skb, struct net_device *dev)
 380 {
 381         struct tun_struct *tun = netdev_priv(dev);
 382
 383         tun_debug(KERN_INFO, tun, "tun_net_xmit %d\n", skb->len);
 384
 385         /* Drop packet if interface is not attached */
 386         if (!tun->tfile)
 387                 goto drop;
 388
 389         /* Drop if the filter does not like it.
 390          * This is a noop if the filter is disabled.
 391          * Filter can be enabled only for the TAP devices. */
 392         if (!check_filter(&tun->txflt, skb))
 393                 goto drop;
 394
 395         if (tun->socket.sk->sk_filter &&
 396             sk_filter(tun->socket.sk, skb))
 397                 goto drop;
 398
 399         if (skb_queue_len(&tun->socket.sk->sk_receive_queue) >= dev->tx_queue_len) {
 400                 if (!(tun->flags & TUN_ONE_QUEUE)) {
 401                         /* Normal queueing mode. */
 402                         /* Packet scheduler handles dropping of further packets. */
 403                         netif_stop_queue(dev);
 404
 405                         /* We won't see all dropped packets individually, so overrun
 406                          * error is more appropriate. */
 407                         dev->stats.tx_fifo_errors++;
 408                 } else {
 409                         /* Single queue mode.
 410                          * Driver handles dropping of all packets itself. */
 411                         goto drop;
 412                 }
 413         }
 414
 415         /* Orphan the skb - required as we might hang on to it
 416          * for indefinite time. */
 417         skb_orphan(skb);
 418
 419         /* Enqueue packet */
 420         skb_queue_tail(&tun->socket.sk->sk_receive_queue, skb);
 421
 422         /* Notify and wake up reader process */
 423         if (tun->flags & TUN_FASYNC)
 424                 kill_fasync(&tun->fasync, SIGIO, POLL_IN);
 425         wake_up_interruptible_poll(&tun->wq.wait, POLLIN |
 426                                    POLLRDNORM | POLLRDBAND);
 427         return NETDEV_TX_OK;
 428
 429 drop:
 430         dev->stats.tx_dropped++;
 431         kfree_skb(skb);
 432         return NETDEV_TX_OK;
 433 }
 434
 435 static void tun_net_mclist(struct net_device *dev)
 436 {
 437         /*
 438          * This callback is supposed to deal with mc filter in
 439          * _rx_ path and has nothing to do with the _tx_ path.
 440          * In rx path we always accept everything userspace gives us.
 441          */
 442 }
 443
 444 #define MIN_MTU 68
 445 #define MAX_MTU 65535
 446
 447 static int
 448 tun_net_change_mtu(struct net_device *dev, int new_mtu)
 449 {
 450         if (new_mtu < MIN_MTU || new_mtu + dev->hard_header_len > MAX_MTU)
 451                 return -EINVAL;
 452         dev->mtu = new_mtu;
 453         return 0;
 454 }
 455
 456 static netdev_features_t tun_net_fix_features(struct net_device *dev,
 457         netdev_features_t features)
 458 {
 459         struct tun_struct *tun = netdev_priv(dev);
 460
 461         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 462 }
 463 #ifdef CONFIG_NET_POLL_CONTROLLER
 464 static void tun_poll_controller(struct net_device *dev)
 465 {
 466         /*
 467          * Tun only receives frames when:
 468          * 1) the char device endpoint gets data from user space
 469          * 2) the tun socket gets a sendmsg call from user space
 470          * Since both of those are syncronous operations, we are guaranteed
 471          * never to have pending data when we poll for it
 472          * so theres nothing to do here but return.
 473          * We need this though so netpoll recognizes us as an interface that
 474          * supports polling, which enables bridge devices in virt setups to
 475          * still use netconsole
 476          */
 477         return;
 478 }
 479 #endif
 480 static const struct net_device_ops tun_netdev_ops = {
 481         .ndo_uninit             = tun_net_uninit,
 482         .ndo_open               = tun_net_open,
 483         .ndo_stop               = tun_net_close,
 484         .ndo_start_xmit         = tun_net_xmit,
 485         .ndo_change_mtu         = tun_net_change_mtu,
 486         .ndo_fix_features       = tun_net_fix_features,
 487 #ifdef CONFIG_NET_POLL_CONTROLLER
 488         .ndo_poll_controller    = tun_poll_controller,
 489 #endif
 490 };
 491
 492 static const struct net_device_ops tap_netdev_ops = {
 493         .ndo_uninit             = tun_net_uninit,
 494         .ndo_open               = tun_net_open,
 495         .ndo_stop               = tun_net_close,
 496         .ndo_start_xmit         = tun_net_xmit,
 497         .ndo_change_mtu         = tun_net_change_mtu,
 498         .ndo_fix_features       = tun_net_fix_features,
 499         .ndo_set_rx_mode        = tun_net_mclist,
 500         .ndo_set_mac_address    = eth_mac_addr,
 501         .ndo_validate_addr      = eth_validate_addr,
 502 #ifdef CONFIG_NET_POLL_CONTROLLER
 503         .ndo_poll_controller    = tun_poll_controller,
 504 #endif
 505 };
 506
 507 /* Initialize net device. */
 508 static void tun_net_init(struct net_device *dev)
 509 {
 510         struct tun_struct *tun = netdev_priv(dev);
 511
 512         switch (tun->flags & TUN_TYPE_MASK) {
 513         case TUN_TUN_DEV:
 514                 dev->netdev_ops = &tun_netdev_ops;
 515
 516                 /* Point-to-Point TUN Device */
 517                 dev->hard_header_len = 0;
 518                 dev->addr_len = 0;
 519                 dev->mtu = 1500;
 520
 521                 /* Zero header length */
 522                 dev->type = ARPHRD_NONE;
 523                 dev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
 524                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 525                 break;
 526
 527         case TUN_TAP_DEV:
 528                 dev->netdev_ops = &tap_netdev_ops;
 529                 /* Ethernet TAP Device */
 530                 ether_setup(dev);
 531                 dev->priv_flags &= ~IFF_TX_SKB_SHARING;
 532
 533                 eth_hw_addr_random(dev);
 534
 535                 dev->tx_queue_len = TUN_READQ_SIZE;  /* We prefer our own queue length */
 536                 break;
 537         }
 538 }
 539
 540 /* Character device part */
 541
 542 /* Poll */
 543 static unsigned int tun_chr_poll(struct file *file, poll_table * wait)
 544 {
 545         struct tun_file *tfile = file->private_data;
 546         struct tun_struct *tun = __tun_get(tfile);
 547         struct sock *sk;
 548         unsigned int mask = 0;
 549
 550         if (!tun)
 551                 return POLLERR;
 552
 553         sk = tun->socket.sk;
 554
 555         tun_debug(KERN_INFO, tun, "tun_chr_poll\n");
 556
 557         poll_wait(file, &tun->wq.wait, wait);
 558
 559         if (!skb_queue_empty(&sk->sk_receive_queue))
 560                 mask |= POLLIN | POLLRDNORM;
 561
 562         if (sock_writeable(sk) ||
 563             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 564              sock_writeable(sk)))
 565                 mask |= POLLOUT | POLLWRNORM;
 566
 567         if (tun->dev->reg_state != NETREG_REGISTERED)
 568                 mask = POLLERR;
 569
 570         tun_put(tun);
 571         return mask;
 572 }
 573
 574 /* prepad is the amount to reserve at front.  len is length after that.
 575  * linear is a hint as to how much to copy (usually headers). */
 576 static struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 577                                      size_t prepad, size_t len,
 578                                      size_t linear, int noblock)
 579 {
 580         struct sock *sk = tun->socket.sk;
 581         struct sk_buff *skb;
 582         int err;
 583
 584         sock_update_classid(sk);
 585
 586         /* Under a page?  Don't bother with paged skb. */
 587         if (prepad + len < PAGE_SIZE || !linear)
 588                 linear = len;
 589
 590         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 591                                    &err);
 592         if (!skb)
 593                 return ERR_PTR(err);
 594
 595         skb_reserve(skb, prepad);
 596         skb_put(skb, linear);
 597         skb->data_len = len - linear;
 598         skb->len += len - linear;
 599
 600         return skb;
 601 }
 602
 603 /* Get packet from user space buffer */
 604 static ssize_t tun_get_user(struct tun_struct *tun,
 605                             const struct iovec *iv, size_t count,
 606                             int noblock)
 607 {
 608         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 609         struct sk_buff *skb;
 610         size_t len = count, align = NET_SKB_PAD;
 611         struct virtio_net_hdr gso = { 0 };
 612         int offset = 0;
 613
 614         if (!(tun->flags & TUN_NO_PI)) {
 615                 if ((len -= sizeof(pi)) > count)
 616                         return -EINVAL;
 617
 618                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 619                         return -EFAULT;
 620                 offset += sizeof(pi);
 621         }
 622
 623         if (tun->flags & TUN_VNET_HDR) {
 624                 if ((len -= tun->vnet_hdr_sz) > count)
 625                         return -EINVAL;
 626
 627                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 628                         return -EFAULT;
 629
 630                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 631                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 632                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 633
 634                 if (gso.hdr_len > len)
 635                         return -EINVAL;
 636                 offset += tun->vnet_hdr_sz;
 637         }
 638
 639         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 640                 align += NET_IP_ALIGN;
 641                 if (unlikely(len < ETH_HLEN ||
 642                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 643                         return -EINVAL;
 644         }
 645
 646         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 647         if (IS_ERR(skb)) {
 648                 if (PTR_ERR(skb) != -EAGAIN)
 649                         tun->dev->stats.rx_dropped++;
 650                 return PTR_ERR(skb);
 651         }
 652
 653         if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
 654                 tun->dev->stats.rx_dropped++;
 655                 kfree_skb(skb);
 656                 return -EFAULT;
 657         }
 658
 659         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 660                 if (!skb_partial_csum_set(skb, gso.csum_start,
 661                                           gso.csum_offset)) {
 662                         tun->dev->stats.rx_frame_errors++;
 663                         kfree_skb(skb);
 664                         return -EINVAL;
 665                 }
 666         }
 667
 668         switch (tun->flags & TUN_TYPE_MASK) {
 669         case TUN_TUN_DEV:
 670                 if (tun->flags & TUN_NO_PI) {
 671                         switch (skb->data[0] & 0xf0) {
 672                         case 0x40:
 673                                 pi.proto = htons(ETH_P_IP);
 674                                 break;
 675                         case 0x60:
 676                                 pi.proto = htons(ETH_P_IPV6);
 677                                 break;
 678                         default:
 679                                 tun->dev->stats.rx_dropped++;
 680                                 kfree_skb(skb);
 681                                 return -EINVAL;
 682                         }
 683                 }
 684
 685                 skb_reset_mac_header(skb);
 686                 skb->protocol = pi.proto;
 687                 skb->dev = tun->dev;
 688                 break;
 689         case TUN_TAP_DEV:
 690                 skb->protocol = eth_type_trans(skb, tun->dev);
 691                 break;
 692         }
 693
 694         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 695                 pr_debug("GSO!\n");
 696                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 697                 case VIRTIO_NET_HDR_GSO_TCPV4:
 698                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 699                         break;
 700                 case VIRTIO_NET_HDR_GSO_TCPV6:
 701                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 702                         break;
 703                 case VIRTIO_NET_HDR_GSO_UDP:
 704                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 705                         break;
 706                 default:
 707                         tun->dev->stats.rx_frame_errors++;
 708                         kfree_skb(skb);
 709                         return -EINVAL;
 710                 }
 711
 712                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 713                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 714
 715                 skb_shinfo(skb)->gso_size = gso.gso_size;
 716                 if (skb_shinfo(skb)->gso_size == 0) {
 717                         tun->dev->stats.rx_frame_errors++;
 718                         kfree_skb(skb);
 719                         return -EINVAL;
 720                 }
 721
 722                 /* Header must be checked, and gso_segs computed. */
 723                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 724                 skb_shinfo(skb)->gso_segs = 0;
 725         }
 726
 727         netif_rx_ni(skb);
 728
 729         tun->dev->stats.rx_packets++;
 730         tun->dev->stats.rx_bytes += len;
 731
 732         return count;
 733 }
 734
 735 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 736                               unsigned long count, loff_t pos)
 737 {
 738         struct file *file = iocb->ki_filp;
 739         struct tun_struct *tun = tun_get(file);
 740         ssize_t result;
 741
 742         if (!tun)
 743                 return -EBADFD;
 744
 745         tun_debug(KERN_INFO, tun, "tun_chr_write %ld\n", count);
 746
 747         result = tun_get_user(tun, iv, iov_length(iv, count),
 748                               file->f_flags & O_NONBLOCK);
 749
 750         tun_put(tun);
 751         return result;
 752 }
 753
 754 /* Put packet to the user space buffer */
 755 static ssize_t tun_put_user(struct tun_struct *tun,
 756                             struct sk_buff *skb,
 757                             const struct iovec *iv, int len)
 758 {
 759         struct tun_pi pi = { 0, skb->protocol };
 760         ssize_t total = 0;
 761
 762         if (!(tun->flags & TUN_NO_PI)) {
 763                 if ((len -= sizeof(pi)) < 0)
 764                         return -EINVAL;
 765
 766                 if (len < skb->len) {
 767                         /* Packet will be striped */
 768                         pi.flags |= TUN_PKT_STRIP;
 769                 }
 770
 771                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 772                         return -EFAULT;
 773                 total += sizeof(pi);
 774         }
 775
 776         if (tun->flags & TUN_VNET_HDR) {
 777                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 778                 if ((len -= tun->vnet_hdr_sz) < 0)
 779                         return -EINVAL;
 780
 781                 if (skb_is_gso(skb)) {
 782                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 783
 784                         /* This is a hint as to how much should be linear. */
 785                         gso.hdr_len = skb_headlen(skb);
 786                         gso.gso_size = sinfo->gso_size;
 787                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 788                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 789                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 790                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 791                         else if (sinfo->gso_type & SKB_GSO_UDP)
 792                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 793                         else {
 794                                 pr_err("unexpected GSO type: "
 795                                        "0x%x, gso_size %d, hdr_len %d\n",
 796                                        sinfo->gso_type, gso.gso_size,
 797                                        gso.hdr_len);
 798                                 print_hex_dump(KERN_ERR, "tun: ",
 799                                                DUMP_PREFIX_NONE,
 800                                                16, 1, skb->head,
 801                                                min((int)gso.hdr_len, 64), true);
 802                                 WARN_ON_ONCE(1);
 803                                 return -EINVAL;
 804                         }
 805                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 806                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 807                 } else
 808                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 809
 810                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 811                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 812                         gso.csum_start = skb_checksum_start_offset(skb);
 813                         gso.csum_offset = skb->csum_offset;
 814                 } else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
 815                         gso.flags = VIRTIO_NET_HDR_F_DATA_VALID;
 816                 } /* else everything is zero */
 817
 818                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 819                                                sizeof(gso))))
 820                         return -EFAULT;
 821                 total += tun->vnet_hdr_sz;
 822         }
 823
 824         len = min_t(int, skb->len, len);
 825
 826         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 827         total += skb->len;
 828
 829         tun->dev->stats.tx_packets++;
 830         tun->dev->stats.tx_bytes += len;
 831
 832         return total;
 833 }
 834
 835 static ssize_t tun_do_read(struct tun_struct *tun,
 836                            struct kiocb *iocb, const struct iovec *iv,
 837                            ssize_t len, int noblock)
 838 {
 839         DECLARE_WAITQUEUE(wait, current);
 840         struct sk_buff *skb;
 841         ssize_t ret = 0;
 842
 843         tun_debug(KERN_INFO, tun, "tun_chr_read\n");
 844
 845         if (unlikely(!noblock))
 846                 add_wait_queue(&tun->wq.wait, &wait);
 847         while (len) {
 848                 current->state = TASK_INTERRUPTIBLE;
 849
 850                 /* Read frames from the queue */
 851                 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 852                         if (noblock) {
 853                                 ret = -EAGAIN;
 854                                 break;
 855                         }
 856                         if (signal_pending(current)) {
 857                                 ret = -ERESTARTSYS;
 858                                 break;
 859                         }
 860                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 861                                 ret = -EIO;
 862                                 break;
 863                         }
 864
 865                         /* Nothing to read, let's sleep */
 866                         schedule();
 867                         continue;
 868                 }
 869                 netif_wake_queue(tun->dev);
 870
 871                 ret = tun_put_user(tun, skb, iv, len);
 872                 kfree_skb(skb);
 873                 break;
 874         }
 875
 876         current->state = TASK_RUNNING;
 877         if (unlikely(!noblock))
 878                 remove_wait_queue(&tun->wq.wait, &wait);
 879
 880         return ret;
 881 }
 882
 883 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 884                             unsigned long count, loff_t pos)
 885 {
 886         struct file *file = iocb->ki_filp;
 887         struct tun_file *tfile = file->private_data;
 888         struct tun_struct *tun = __tun_get(tfile);
 889         ssize_t len, ret;
 890
 891         if (!tun)
 892                 return -EBADFD;
 893         len = iov_length(iv, count);
 894         if (len < 0) {
 895                 ret = -EINVAL;
 896                 goto out;
 897         }
 898
 899         ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
 900         ret = min_t(ssize_t, ret, len);
 901 out:
 902         tun_put(tun);
 903         return ret;
 904 }
 905
 906 static void tun_setup(struct net_device *dev)
 907 {
 908         struct tun_struct *tun = netdev_priv(dev);
 909
 910         tun->owner = -1;
 911         tun->group = -1;
 912
 913         dev->ethtool_ops = &tun_ethtool_ops;
 914         dev->destructor = tun_free_netdev;
 915 }
 916
 917 /* Trivial set of netlink ops to allow deleting tun or tap
 918  * device with netlink.
 919  */
 920 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 921 {
 922         return -EINVAL;
 923 }
 924
 925 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 926         .kind           = DRV_NAME,
 927         .priv_size      = sizeof(struct tun_struct),
 928         .setup          = tun_setup,
 929         .validate       = tun_validate,
 930 };
 931
 932 static void tun_sock_write_space(struct sock *sk)
 933 {
 934         struct tun_struct *tun;
 935         wait_queue_head_t *wqueue;
 936
 937         if (!sock_writeable(sk))
 938                 return;
 939
 940         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 941                 return;
 942
 943         wqueue = sk_sleep(sk);
 944         if (wqueue && waitqueue_active(wqueue))
 945                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
 946                                                 POLLWRNORM | POLLWRBAND);
 947
 948         tun = tun_sk(sk)->tun;
 949         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 950 }
 951
 952 static void tun_sock_destruct(struct sock *sk)
 953 {
 954         free_netdev(tun_sk(sk)->tun->dev);
 955 }
 956
 957 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
 958                        struct msghdr *m, size_t total_len)
 959 {
 960         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 961         return tun_get_user(tun, m->msg_iov, total_len,
 962                             m->msg_flags & MSG_DONTWAIT);
 963 }
 964
 965 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 966                        struct msghdr *m, size_t total_len,
 967                        int flags)
 968 {
 969         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 970         int ret;
 971         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
 972                 return -EINVAL;
 973         ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
 974                           flags & MSG_DONTWAIT);
 975         if (ret > total_len) {
 976                 m->msg_flags |= MSG_TRUNC;
 977                 ret = flags & MSG_TRUNC ? ret : total_len;
 978         }
 979         return ret;
 980 }
 981
 982 static int tun_release(struct socket *sock)
 983 {
 984         if (sock->sk)
 985                 sock_put(sock->sk);
 986         return 0;
 987 }
 988
 989 /* Ops structure to mimic raw sockets with tun */
 990 static const struct proto_ops tun_socket_ops = {
 991         .sendmsg = tun_sendmsg,
 992         .recvmsg = tun_recvmsg,
 993         .release = tun_release,
 994 };
 995
 996 static struct proto tun_proto = {
 997         .name           = "tun",
 998         .owner          = THIS_MODULE,
 999         .obj_size       = sizeof(struct tun_sock),
1000 };
1001
1002 static int tun_flags(struct tun_struct *tun)
1003 {
1004         int flags = 0;
1005
1006         if (tun->flags & TUN_TUN_DEV)
1007                 flags |= IFF_TUN;
1008         else
1009                 flags |= IFF_TAP;
1010
1011         if (tun->flags & TUN_NO_PI)
1012                 flags |= IFF_NO_PI;
1013
1014         if (tun->flags & TUN_ONE_QUEUE)
1015                 flags |= IFF_ONE_QUEUE;
1016
1017         if (tun->flags & TUN_VNET_HDR)
1018                 flags |= IFF_VNET_HDR;
1019
1020         return flags;
1021 }
1022
1023 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
1024                               char *buf)
1025 {
1026         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1027         return sprintf(buf, "0x%x\n", tun_flags(tun));
1028 }
1029
1030 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
1031                               char *buf)
1032 {
1033         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1034         return sprintf(buf, "%d\n", tun->owner);
1035 }
1036
1037 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1038                               char *buf)
1039 {
1040         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1041         return sprintf(buf, "%d\n", tun->group);
1042 }
1043
1044 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1045 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1046 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1047
1048 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1049 {
1050         struct sock *sk;
1051         struct tun_struct *tun;
1052         struct net_device *dev;
1053         int err;
1054
1055         dev = __dev_get_by_name(net, ifr->ifr_name);
1056         if (dev) {
1057                 const struct cred *cred = current_cred();
1058
1059                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1060                         return -EBUSY;
1061                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1062                         tun = netdev_priv(dev);
1063                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1064                         tun = netdev_priv(dev);
1065                 else
1066                         return -EINVAL;
1067
1068                 if (((tun->owner != -1 && cred->euid != tun->owner) ||
1069                      (tun->group != -1 && !in_egroup_p(tun->group))) &&
1070                     !capable(CAP_NET_ADMIN))
1071                         return -EPERM;
1072                 err = security_tun_dev_attach(tun->socket.sk);
1073                 if (err < 0)
1074                         return err;
1075
1076                 err = tun_attach(tun, file);
1077                 if (err < 0)
1078                         return err;
1079         }
1080         else {
1081                 char *name;
1082                 unsigned long flags = 0;
1083
1084                 if (!capable(CAP_NET_ADMIN))
1085                         return -EPERM;
1086                 err = security_tun_dev_create();
1087                 if (err < 0)
1088                         return err;
1089
1090                 /* Set dev type */
1091                 if (ifr->ifr_flags & IFF_TUN) {
1092                         /* TUN device */
1093                         flags |= TUN_TUN_DEV;
1094                         name = "tun%d";
1095                 } else if (ifr->ifr_flags & IFF_TAP) {
1096                         /* TAP device */
1097                         flags |= TUN_TAP_DEV;
1098                         name = "tap%d";
1099                 } else
1100                         return -EINVAL;
1101
1102                 if (*ifr->ifr_name)
1103                         name = ifr->ifr_name;
1104
1105                 dev = alloc_netdev(sizeof(struct tun_struct), name,
1106                                    tun_setup);
1107                 if (!dev)
1108                         return -ENOMEM;
1109
1110                 dev_net_set(dev, net);
1111                 dev->rtnl_link_ops = &tun_link_ops;
1112
1113                 tun = netdev_priv(dev);
1114                 tun->dev = dev;
1115                 tun->flags = flags;
1116                 tun->txflt.count = 0;
1117                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1118
1119                 err = -ENOMEM;
1120                 sk = sk_alloc(&init_net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1121                 if (!sk)
1122                         goto err_free_dev;
1123
1124                 sk_change_net(sk, net);
1125                 tun->socket.wq = &tun->wq;
1126                 init_waitqueue_head(&tun->wq.wait);
1127                 tun->socket.ops = &tun_socket_ops;
1128                 sock_init_data(&tun->socket, sk);
1129                 sk->sk_write_space = tun_sock_write_space;
1130                 sk->sk_sndbuf = INT_MAX;
1131
1132                 tun_sk(sk)->tun = tun;
1133
1134                 security_tun_dev_post_create(sk);
1135
1136                 tun_net_init(dev);
1137
1138                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1139                         TUN_USER_FEATURES;
1140                 dev->features = dev->hw_features;
1141
1142                 err = register_netdevice(tun->dev);
1143                 if (err < 0)
1144                         goto err_free_sk;
1145
1146                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1147                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1148                     device_create_file(&tun->dev->dev, &dev_attr_group))
1149                         pr_err("Failed to create tun sysfs files\n");
1150
1151                 sk->sk_destruct = tun_sock_destruct;
1152
1153                 err = tun_attach(tun, file);
1154                 if (err < 0)
1155                         goto failed;
1156         }
1157
1158         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1159
1160         if (ifr->ifr_flags & IFF_NO_PI)
1161                 tun->flags |= TUN_NO_PI;
1162         else
1163                 tun->flags &= ~TUN_NO_PI;
1164
1165         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1166                 tun->flags |= TUN_ONE_QUEUE;
1167         else
1168                 tun->flags &= ~TUN_ONE_QUEUE;
1169
1170         if (ifr->ifr_flags & IFF_VNET_HDR)
1171                 tun->flags |= TUN_VNET_HDR;
1172         else
1173                 tun->flags &= ~TUN_VNET_HDR;
1174
1175         /* Make sure persistent devices do not get stuck in
1176          * xoff state.
1177          */
1178         if (netif_running(tun->dev))
1179                 netif_wake_queue(tun->dev);
1180
1181         strcpy(ifr->ifr_name, tun->dev->name);
1182         return 0;
1183
1184  err_free_sk:
1185         tun_free_netdev(dev);
1186  err_free_dev:
1187         free_netdev(dev);
1188  failed:
1189         return err;
1190 }
1191
1192 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1193                        struct ifreq *ifr)
1194 {
1195         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1196
1197         strcpy(ifr->ifr_name, tun->dev->name);
1198
1199         ifr->ifr_flags = tun_flags(tun);
1200
1201         return 0;
1202 }
1203
1204 /* This is like a cut-down ethtool ops, except done via tun fd so no
1205  * privs required. */
1206 static int set_offload(struct tun_struct *tun, unsigned long arg)
1207 {
1208         netdev_features_t features = 0;
1209
1210         if (arg & TUN_F_CSUM) {
1211                 features |= NETIF_F_HW_CSUM;
1212                 arg &= ~TUN_F_CSUM;
1213
1214                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1215                         if (arg & TUN_F_TSO_ECN) {
1216                                 features |= NETIF_F_TSO_ECN;
1217                                 arg &= ~TUN_F_TSO_ECN;
1218                         }
1219                         if (arg & TUN_F_TSO4)
1220                                 features |= NETIF_F_TSO;
1221                         if (arg & TUN_F_TSO6)
1222                                 features |= NETIF_F_TSO6;
1223                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1224                 }
1225
1226                 if (arg & TUN_F_UFO) {
1227                         features |= NETIF_F_UFO;
1228                         arg &= ~TUN_F_UFO;
1229                 }
1230         }
1231
1232         /* This gives the user a way to test for new features in future by
1233          * trying to set them. */
1234         if (arg)
1235                 return -EINVAL;
1236
1237         tun->set_features = features;
1238         netdev_update_features(tun->dev);
1239
1240         return 0;
1241 }
1242
1243 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1244                             unsigned long arg, int ifreq_len)
1245 {
1246         struct tun_file *tfile = file->private_data;
1247         struct tun_struct *tun;
1248         void __user* argp = (void __user*)arg;
1249         struct sock_fprog fprog;
1250         struct ifreq ifr;
1251         int sndbuf;
1252         int vnet_hdr_sz;
1253         int ret;
1254
1255         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1256                 if (copy_from_user(&ifr, argp, ifreq_len))
1257                         return -EFAULT;
1258
1259         if (cmd == TUNGETFEATURES) {
1260                 /* Currently this just means: "what IFF flags are valid?".
1261                  * This is needed because we never checked for invalid flags on
1262                  * TUNSETIFF. */
1263                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1264                                 IFF_VNET_HDR,
1265                                 (unsigned int __user*)argp);
1266         }
1267
1268         rtnl_lock();
1269
1270         tun = __tun_get(tfile);
1271         if (cmd == TUNSETIFF && !tun) {
1272                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1273
1274                 ret = tun_set_iff(tfile->net, file, &ifr);
1275
1276                 if (ret)
1277                         goto unlock;
1278
1279                 if (copy_to_user(argp, &ifr, ifreq_len))
1280                         ret = -EFAULT;
1281                 goto unlock;
1282         }
1283
1284         ret = -EBADFD;
1285         if (!tun)
1286                 goto unlock;
1287
1288         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1289
1290         ret = 0;
1291         switch (cmd) {
1292         case TUNGETIFF:
1293                 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1294                 if (ret)
1295                         break;
1296
1297                 if (copy_to_user(argp, &ifr, ifreq_len))
1298                         ret = -EFAULT;
1299                 break;
1300
1301         case TUNSETNOCSUM:
1302                 /* Disable/Enable checksum */
1303
1304                 /* [unimplemented] */
1305                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1306                           arg ? "disabled" : "enabled");
1307                 break;
1308
1309         case TUNSETPERSIST:
1310                 /* Disable/Enable persist mode */
1311                 if (arg)
1312                         tun->flags |= TUN_PERSIST;
1313                 else
1314                         tun->flags &= ~TUN_PERSIST;
1315
1316                 tun_debug(KERN_INFO, tun, "persist %s\n",
1317                           arg ? "enabled" : "disabled");
1318                 break;
1319
1320         case TUNSETOWNER:
1321                 /* Set owner of the device */
1322                 tun->owner = (uid_t) arg;
1323
1324                 tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner);
1325                 break;
1326
1327         case TUNSETGROUP:
1328                 /* Set group of the device */
1329                 tun->group= (gid_t) arg;
1330
1331                 tun_debug(KERN_INFO, tun, "group set to %d\n", tun->group);
1332                 break;
1333
1334         case TUNSETLINK:
1335                 /* Only allow setting the type when the interface is down */
1336                 if (tun->dev->flags & IFF_UP) {
1337                         tun_debug(KERN_INFO, tun,
1338                                   "Linktype set failed because interface is up\n");
1339                         ret = -EBUSY;
1340                 } else {
1341                         tun->dev->type = (int) arg;
1342                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1343                                   tun->dev->type);
1344                         ret = 0;
1345                 }
1346                 break;
1347
1348 #ifdef TUN_DEBUG
1349         case TUNSETDEBUG:
1350                 tun->debug = arg;
1351                 break;
1352 #endif
1353         case TUNSETOFFLOAD:
1354                 ret = set_offload(tun, arg);
1355                 break;
1356
1357         case TUNSETTXFILTER:
1358                 /* Can be set only for TAPs */
1359                 ret = -EINVAL;
1360                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1361                         break;
1362                 ret = update_filter(&tun->txflt, (void __user *)arg);
1363                 break;
1364
1365         case SIOCGIFHWADDR:
1366                 /* Get hw address */
1367                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1368                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1369                 if (copy_to_user(argp, &ifr, ifreq_len))
1370                         ret = -EFAULT;
1371                 break;
1372
1373         case SIOCSIFHWADDR:
1374                 /* Set hw address */
1375                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1376                           ifr.ifr_hwaddr.sa_data);
1377
1378                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1379                 break;
1380
1381         case TUNGETSNDBUF:
1382                 sndbuf = tun->socket.sk->sk_sndbuf;
1383                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1384                         ret = -EFAULT;
1385                 break;
1386
1387         case TUNSETSNDBUF:
1388                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1389                         ret = -EFAULT;
1390                         break;
1391                 }
1392
1393                 tun->socket.sk->sk_sndbuf = sndbuf;
1394                 break;
1395
1396         case TUNGETVNETHDRSZ:
1397                 vnet_hdr_sz = tun->vnet_hdr_sz;
1398                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1399                         ret = -EFAULT;
1400                 break;
1401
1402         case TUNSETVNETHDRSZ:
1403                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1404                         ret = -EFAULT;
1405                         break;
1406                 }
1407                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1408                         ret = -EINVAL;
1409                         break;
1410                 }
1411
1412                 tun->vnet_hdr_sz = vnet_hdr_sz;
1413                 break;
1414
1415         case TUNATTACHFILTER:
1416                 /* Can be set only for TAPs */
1417                 ret = -EINVAL;
1418                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1419                         break;
1420                 ret = -EFAULT;
1421                 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1422                         break;
1423
1424                 ret = sk_attach_filter(&fprog, tun->socket.sk);
1425                 break;
1426
1427         case TUNDETACHFILTER:
1428                 /* Can be set only for TAPs */
1429                 ret = -EINVAL;
1430                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1431                         break;
1432                 ret = sk_detach_filter(tun->socket.sk);
1433                 break;
1434
1435         default:
1436                 ret = -EINVAL;
1437                 break;
1438         }
1439
1440 unlock:
1441         rtnl_unlock();
1442         if (tun)
1443                 tun_put(tun);
1444         return ret;
1445 }
1446
1447 static long tun_chr_ioctl(struct file *file,
1448                           unsigned int cmd, unsigned long arg)
1449 {
1450         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1451 }
1452
1453 #ifdef CONFIG_COMPAT
1454 static long tun_chr_compat_ioctl(struct file *file,
1455                          unsigned int cmd, unsigned long arg)
1456 {
1457         switch (cmd) {
1458         case TUNSETIFF:
1459         case TUNGETIFF:
1460         case TUNSETTXFILTER:
1461         case TUNGETSNDBUF:
1462         case TUNSETSNDBUF:
1463         case SIOCGIFHWADDR:
1464         case SIOCSIFHWADDR:
1465                 arg = (unsigned long)compat_ptr(arg);
1466                 break;
1467         default:
1468                 arg = (compat_ulong_t)arg;
1469                 break;
1470         }
1471
1472         /*
1473          * compat_ifreq is shorter than ifreq, so we must not access beyond
1474          * the end of that structure. All fields that are used in this
1475          * driver are compatible though, we don't need to convert the
1476          * contents.
1477          */
1478         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1479 }
1480 #endif /* CONFIG_COMPAT */
1481
1482 static int tun_chr_fasync(int fd, struct file *file, int on)
1483 {
1484         struct tun_struct *tun = tun_get(file);
1485         int ret;
1486
1487         if (!tun)
1488                 return -EBADFD;
1489
1490         tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1491
1492         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1493                 goto out;
1494
1495         if (on) {
1496                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1497                 if (ret)
1498                         goto out;
1499                 tun->flags |= TUN_FASYNC;
1500         } else
1501                 tun->flags &= ~TUN_FASYNC;
1502         ret = 0;
1503 out:
1504         tun_put(tun);
1505         return ret;
1506 }
1507
1508 static int tun_chr_open(struct inode *inode, struct file * file)
1509 {
1510         struct tun_file *tfile;
1511
1512         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1513
1514         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1515         if (!tfile)
1516                 return -ENOMEM;
1517         atomic_set(&tfile->count, 0);
1518         tfile->tun = NULL;
1519         tfile->net = get_net(current->nsproxy->net_ns);
1520         file->private_data = tfile;
1521         return 0;
1522 }
1523
1524 static int tun_chr_close(struct inode *inode, struct file *file)
1525 {
1526         struct tun_file *tfile = file->private_data;
1527         struct tun_struct *tun;
1528
1529         tun = __tun_get(tfile);
1530         if (tun) {
1531                 struct net_device *dev = tun->dev;
1532
1533                 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1534
1535                 __tun_detach(tun);
1536
1537                 /* If desirable, unregister the netdevice. */
1538                 if (!(tun->flags & TUN_PERSIST)) {
1539                         rtnl_lock();
1540                         if (dev->reg_state == NETREG_REGISTERED)
1541                                 unregister_netdevice(dev);
1542                         rtnl_unlock();
1543                 }
1544         }
1545
1546         tun = tfile->tun;
1547         if (tun)
1548                 sock_put(tun->socket.sk);
1549
1550         put_net(tfile->net);
1551         kfree(tfile);
1552
1553         return 0;
1554 }
1555
1556 static const struct file_operations tun_fops = {
1557         .owner  = THIS_MODULE,
1558         .llseek = no_llseek,
1559         .read  = do_sync_read,
1560         .aio_read  = tun_chr_aio_read,
1561         .write = do_sync_write,
1562         .aio_write = tun_chr_aio_write,
1563         .poll   = tun_chr_poll,
1564         .unlocked_ioctl = tun_chr_ioctl,
1565 #ifdef CONFIG_COMPAT
1566         .compat_ioctl = tun_chr_compat_ioctl,
1567 #endif
1568         .open   = tun_chr_open,
1569         .release = tun_chr_close,
1570         .fasync = tun_chr_fasync
1571 };
1572
1573 static struct miscdevice tun_miscdev = {
1574         .minor = TUN_MINOR,
1575         .name = "tun",
1576         .nodename = "net/tun",
1577         .fops = &tun_fops,
1578 };
1579
1580 /* ethtool interface */
1581
1582 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1583 {
1584         cmd->supported          = 0;
1585         cmd->advertising        = 0;
1586         ethtool_cmd_speed_set(cmd, SPEED_10);
1587         cmd->duplex             = DUPLEX_FULL;
1588         cmd->port               = PORT_TP;
1589         cmd->phy_address        = 0;
1590         cmd->transceiver        = XCVR_INTERNAL;
1591         cmd->autoneg            = AUTONEG_DISABLE;
1592         cmd->maxtxpkt           = 0;
1593         cmd->maxrxpkt           = 0;
1594         return 0;
1595 }
1596
1597 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1598 {
1599         struct tun_struct *tun = netdev_priv(dev);
1600
1601         strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
1602         strlcpy(info->version, DRV_VERSION, sizeof(info->version));
1603
1604         switch (tun->flags & TUN_TYPE_MASK) {
1605         case TUN_TUN_DEV:
1606                 strlcpy(info->bus_info, "tun", sizeof(info->bus_info));
1607                 break;
1608         case TUN_TAP_DEV:
1609                 strlcpy(info->bus_info, "tap", sizeof(info->bus_info));
1610                 break;
1611         }
1612 }
1613
1614 static u32 tun_get_msglevel(struct net_device *dev)
1615 {
1616 #ifdef TUN_DEBUG
1617         struct tun_struct *tun = netdev_priv(dev);
1618         return tun->debug;
1619 #else
1620         return -EOPNOTSUPP;
1621 #endif
1622 }
1623
1624 static void tun_set_msglevel(struct net_device *dev, u32 value)
1625 {
1626 #ifdef TUN_DEBUG
1627         struct tun_struct *tun = netdev_priv(dev);
1628         tun->debug = value;
1629 #endif
1630 }
1631
1632 static const struct ethtool_ops tun_ethtool_ops = {
1633         .get_settings   = tun_get_settings,
1634         .get_drvinfo    = tun_get_drvinfo,
1635         .get_msglevel   = tun_get_msglevel,
1636         .set_msglevel   = tun_set_msglevel,
1637         .get_link       = ethtool_op_get_link,
1638 };
1639
1640
1641 static int __init tun_init(void)
1642 {
1643         int ret = 0;
1644
1645         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1646         pr_info("%s\n", DRV_COPYRIGHT);
1647
1648         ret = rtnl_link_register(&tun_link_ops);
1649         if (ret) {
1650                 pr_err("Can't register link_ops\n");
1651                 goto err_linkops;
1652         }
1653
1654         ret = misc_register(&tun_miscdev);
1655         if (ret) {
1656                 pr_err("Can't register misc device %d\n", TUN_MINOR);
1657                 goto err_misc;
1658         }
1659         return  0;
1660 err_misc:
1661         rtnl_link_unregister(&tun_link_ops);
1662 err_linkops:
1663         return ret;
1664 }
1665
1666 static void tun_cleanup(void)
1667 {
1668         misc_deregister(&tun_miscdev);
1669         rtnl_link_unregister(&tun_link_ops);
1670 }
1671
1672 /* Get an underlying socket object from tun file.  Returns error unless file is
1673  * attached to a device.  The returned object works like a packet socket, it
1674  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1675  * holding a reference to the file for as long as the socket is in use. */
1676 struct socket *tun_get_socket(struct file *file)
1677 {
1678         struct tun_struct *tun;
1679         if (file->f_op != &tun_fops)
1680                 return ERR_PTR(-EINVAL);
1681         tun = tun_get(file);
1682         if (!tun)
1683                 return ERR_PTR(-EBADFD);
1684         tun_put(tun);
1685         return &tun->socket;
1686 }
1687 EXPORT_SYMBOL_GPL(tun_get_socket);
1688
1689 module_init(tun_init);
1690 module_exit(tun_cleanup);
1691 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1692 MODULE_AUTHOR(DRV_COPYRIGHT);
1693 MODULE_LICENSE("GPL");
1694 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1695 MODULE_ALIAS("devname:net/tun");