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