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 inline 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 __inline__ 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 = 0;
 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 __inline__ 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 everything is zero */
 792
 793                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 794                                                sizeof(gso))))
 795                         return -EFAULT;
 796                 total += tun->vnet_hdr_sz;
 797         }
 798
 799         len = min_t(int, skb->len, len);
 800
 801         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 802         total += skb->len;
 803
 804         tun->dev->stats.tx_packets++;
 805         tun->dev->stats.tx_bytes += len;
 806
 807         return total;
 808 }
 809
 810 static ssize_t tun_do_read(struct tun_struct *tun,
 811                            struct kiocb *iocb, const struct iovec *iv,
 812                            ssize_t len, int noblock)
 813 {
 814         DECLARE_WAITQUEUE(wait, current);
 815         struct sk_buff *skb;
 816         ssize_t ret = 0;
 817
 818         tun_debug(KERN_INFO, tun, "tun_chr_read\n");
 819
 820         add_wait_queue(&tun->wq.wait, &wait);
 821         while (len) {
 822                 current->state = TASK_INTERRUPTIBLE;
 823
 824                 /* Read frames from the queue */
 825                 if (!(skb=skb_dequeue(&tun->socket.sk->sk_receive_queue))) {
 826                         if (noblock) {
 827                                 ret = -EAGAIN;
 828                                 break;
 829                         }
 830                         if (signal_pending(current)) {
 831                                 ret = -ERESTARTSYS;
 832                                 break;
 833                         }
 834                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 835                                 ret = -EIO;
 836                                 break;
 837                         }
 838
 839                         /* Nothing to read, let's sleep */
 840                         schedule();
 841                         continue;
 842                 }
 843                 netif_wake_queue(tun->dev);
 844
 845                 ret = tun_put_user(tun, skb, iv, len);
 846                 kfree_skb(skb);
 847                 break;
 848         }
 849
 850         current->state = TASK_RUNNING;
 851         remove_wait_queue(&tun->wq.wait, &wait);
 852
 853         return ret;
 854 }
 855
 856 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 857                             unsigned long count, loff_t pos)
 858 {
 859         struct file *file = iocb->ki_filp;
 860         struct tun_file *tfile = file->private_data;
 861         struct tun_struct *tun = __tun_get(tfile);
 862         ssize_t len, ret;
 863
 864         if (!tun)
 865                 return -EBADFD;
 866         len = iov_length(iv, count);
 867         if (len < 0) {
 868                 ret = -EINVAL;
 869                 goto out;
 870         }
 871
 872         ret = tun_do_read(tun, iocb, iv, len, file->f_flags & O_NONBLOCK);
 873         ret = min_t(ssize_t, ret, len);
 874 out:
 875         tun_put(tun);
 876         return ret;
 877 }
 878
 879 static void tun_setup(struct net_device *dev)
 880 {
 881         struct tun_struct *tun = netdev_priv(dev);
 882
 883         tun->owner = -1;
 884         tun->group = -1;
 885
 886         dev->ethtool_ops = &tun_ethtool_ops;
 887         dev->destructor = tun_free_netdev;
 888 }
 889
 890 /* Trivial set of netlink ops to allow deleting tun or tap
 891  * device with netlink.
 892  */
 893 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 894 {
 895         return -EINVAL;
 896 }
 897
 898 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 899         .kind           = DRV_NAME,
 900         .priv_size      = sizeof(struct tun_struct),
 901         .setup          = tun_setup,
 902         .validate       = tun_validate,
 903 };
 904
 905 static void tun_sock_write_space(struct sock *sk)
 906 {
 907         struct tun_struct *tun;
 908         wait_queue_head_t *wqueue;
 909
 910         if (!sock_writeable(sk))
 911                 return;
 912
 913         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 914                 return;
 915
 916         wqueue = sk_sleep(sk);
 917         if (wqueue && waitqueue_active(wqueue))
 918                 wake_up_interruptible_sync_poll(wqueue, POLLOUT |
 919                                                 POLLWRNORM | POLLWRBAND);
 920
 921         tun = tun_sk(sk)->tun;
 922         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 923 }
 924
 925 static void tun_sock_destruct(struct sock *sk)
 926 {
 927         free_netdev(tun_sk(sk)->tun->dev);
 928 }
 929
 930 static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
 931                        struct msghdr *m, size_t total_len)
 932 {
 933         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 934         return tun_get_user(tun, m->msg_iov, total_len,
 935                             m->msg_flags & MSG_DONTWAIT);
 936 }
 937
 938 static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 939                        struct msghdr *m, size_t total_len,
 940                        int flags)
 941 {
 942         struct tun_struct *tun = container_of(sock, struct tun_struct, socket);
 943         int ret;
 944         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
 945                 return -EINVAL;
 946         ret = tun_do_read(tun, iocb, m->msg_iov, total_len,
 947                           flags & MSG_DONTWAIT);
 948         if (ret > total_len) {
 949                 m->msg_flags |= MSG_TRUNC;
 950                 ret = flags & MSG_TRUNC ? ret : total_len;
 951         }
 952         return ret;
 953 }
 954
 955 /* Ops structure to mimic raw sockets with tun */
 956 static const struct proto_ops tun_socket_ops = {
 957         .sendmsg = tun_sendmsg,
 958         .recvmsg = tun_recvmsg,
 959 };
 960
 961 static struct proto tun_proto = {
 962         .name           = "tun",
 963         .owner          = THIS_MODULE,
 964         .obj_size       = sizeof(struct tun_sock),
 965 };
 966
 967 static int tun_flags(struct tun_struct *tun)
 968 {
 969         int flags = 0;
 970
 971         if (tun->flags & TUN_TUN_DEV)
 972                 flags |= IFF_TUN;
 973         else
 974                 flags |= IFF_TAP;
 975
 976         if (tun->flags & TUN_NO_PI)
 977                 flags |= IFF_NO_PI;
 978
 979         if (tun->flags & TUN_ONE_QUEUE)
 980                 flags |= IFF_ONE_QUEUE;
 981
 982         if (tun->flags & TUN_VNET_HDR)
 983                 flags |= IFF_VNET_HDR;
 984
 985         return flags;
 986 }
 987
 988 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
 989                               char *buf)
 990 {
 991         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 992         return sprintf(buf, "0x%x\n", tun_flags(tun));
 993 }
 994
 995 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
 996                               char *buf)
 997 {
 998         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 999         return sprintf(buf, "%d\n", tun->owner);
1000 }
1001
1002 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
1003                               char *buf)
1004 {
1005         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
1006         return sprintf(buf, "%d\n", tun->group);
1007 }
1008
1009 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
1010 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
1011 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
1012
1013 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
1014 {
1015         struct sock *sk;
1016         struct tun_struct *tun;
1017         struct net_device *dev;
1018         int err;
1019
1020         dev = __dev_get_by_name(net, ifr->ifr_name);
1021         if (dev) {
1022                 const struct cred *cred = current_cred();
1023
1024                 if (ifr->ifr_flags & IFF_TUN_EXCL)
1025                         return -EBUSY;
1026                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
1027                         tun = netdev_priv(dev);
1028                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
1029                         tun = netdev_priv(dev);
1030                 else
1031                         return -EINVAL;
1032
1033                 if (((tun->owner != -1 && cred->euid != tun->owner) ||
1034                      (tun->group != -1 && !in_egroup_p(tun->group))) &&
1035                     !capable(CAP_NET_ADMIN))
1036                         return -EPERM;
1037                 err = security_tun_dev_attach(tun->socket.sk);
1038                 if (err < 0)
1039                         return err;
1040
1041                 err = tun_attach(tun, file);
1042                 if (err < 0)
1043                         return err;
1044         }
1045         else {
1046                 char *name;
1047                 unsigned long flags = 0;
1048
1049                 if (!capable(CAP_NET_ADMIN))
1050                         return -EPERM;
1051                 err = security_tun_dev_create();
1052                 if (err < 0)
1053                         return err;
1054
1055                 /* Set dev type */
1056                 if (ifr->ifr_flags & IFF_TUN) {
1057                         /* TUN device */
1058                         flags |= TUN_TUN_DEV;
1059                         name = "tun%d";
1060                 } else if (ifr->ifr_flags & IFF_TAP) {
1061                         /* TAP device */
1062                         flags |= TUN_TAP_DEV;
1063                         name = "tap%d";
1064                 } else
1065                         return -EINVAL;
1066
1067                 if (*ifr->ifr_name)
1068                         name = ifr->ifr_name;
1069
1070                 dev = alloc_netdev(sizeof(struct tun_struct), name,
1071                                    tun_setup);
1072                 if (!dev)
1073                         return -ENOMEM;
1074
1075                 dev_net_set(dev, net);
1076                 dev->rtnl_link_ops = &tun_link_ops;
1077
1078                 tun = netdev_priv(dev);
1079                 tun->dev = dev;
1080                 tun->flags = flags;
1081                 tun->txflt.count = 0;
1082                 tun->vnet_hdr_sz = sizeof(struct virtio_net_hdr);
1083
1084                 err = -ENOMEM;
1085                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
1086                 if (!sk)
1087                         goto err_free_dev;
1088
1089                 tun->socket.wq = &tun->wq;
1090                 init_waitqueue_head(&tun->wq.wait);
1091                 tun->socket.ops = &tun_socket_ops;
1092                 sock_init_data(&tun->socket, sk);
1093                 sk->sk_write_space = tun_sock_write_space;
1094                 sk->sk_sndbuf = INT_MAX;
1095
1096                 tun_sk(sk)->tun = tun;
1097
1098                 security_tun_dev_post_create(sk);
1099
1100                 tun_net_init(dev);
1101
1102                 dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST |
1103                         TUN_USER_FEATURES;
1104                 dev->features = dev->hw_features;
1105
1106                 err = register_netdevice(tun->dev);
1107                 if (err < 0)
1108                         goto err_free_sk;
1109
1110                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1111                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1112                     device_create_file(&tun->dev->dev, &dev_attr_group))
1113                         pr_err("Failed to create tun sysfs files\n");
1114
1115                 sk->sk_destruct = tun_sock_destruct;
1116
1117                 err = tun_attach(tun, file);
1118                 if (err < 0)
1119                         goto failed;
1120         }
1121
1122         tun_debug(KERN_INFO, tun, "tun_set_iff\n");
1123
1124         if (ifr->ifr_flags & IFF_NO_PI)
1125                 tun->flags |= TUN_NO_PI;
1126         else
1127                 tun->flags &= ~TUN_NO_PI;
1128
1129         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1130                 tun->flags |= TUN_ONE_QUEUE;
1131         else
1132                 tun->flags &= ~TUN_ONE_QUEUE;
1133
1134         if (ifr->ifr_flags & IFF_VNET_HDR)
1135                 tun->flags |= TUN_VNET_HDR;
1136         else
1137                 tun->flags &= ~TUN_VNET_HDR;
1138
1139         /* Make sure persistent devices do not get stuck in
1140          * xoff state.
1141          */
1142         if (netif_running(tun->dev))
1143                 netif_wake_queue(tun->dev);
1144
1145         strcpy(ifr->ifr_name, tun->dev->name);
1146         return 0;
1147
1148  err_free_sk:
1149         sock_put(sk);
1150  err_free_dev:
1151         free_netdev(dev);
1152  failed:
1153         return err;
1154 }
1155
1156 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1157                        struct ifreq *ifr)
1158 {
1159         tun_debug(KERN_INFO, tun, "tun_get_iff\n");
1160
1161         strcpy(ifr->ifr_name, tun->dev->name);
1162
1163         ifr->ifr_flags = tun_flags(tun);
1164
1165         return 0;
1166 }
1167
1168 /* This is like a cut-down ethtool ops, except done via tun fd so no
1169  * privs required. */
1170 static int set_offload(struct tun_struct *tun, unsigned long arg)
1171 {
1172         u32 features = 0;
1173
1174         if (arg & TUN_F_CSUM) {
1175                 features |= NETIF_F_HW_CSUM;
1176                 arg &= ~TUN_F_CSUM;
1177
1178                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1179                         if (arg & TUN_F_TSO_ECN) {
1180                                 features |= NETIF_F_TSO_ECN;
1181                                 arg &= ~TUN_F_TSO_ECN;
1182                         }
1183                         if (arg & TUN_F_TSO4)
1184                                 features |= NETIF_F_TSO;
1185                         if (arg & TUN_F_TSO6)
1186                                 features |= NETIF_F_TSO6;
1187                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1188                 }
1189
1190                 if (arg & TUN_F_UFO) {
1191                         features |= NETIF_F_UFO;
1192                         arg &= ~TUN_F_UFO;
1193                 }
1194         }
1195
1196         /* This gives the user a way to test for new features in future by
1197          * trying to set them. */
1198         if (arg)
1199                 return -EINVAL;
1200
1201         tun->set_features = features;
1202         netdev_update_features(tun->dev);
1203
1204         return 0;
1205 }
1206
1207 static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
1208                             unsigned long arg, int ifreq_len)
1209 {
1210         struct tun_file *tfile = file->private_data;
1211         struct tun_struct *tun;
1212         void __user* argp = (void __user*)arg;
1213         struct sock_fprog fprog;
1214         struct ifreq ifr;
1215         int sndbuf;
1216         int vnet_hdr_sz;
1217         int ret;
1218
1219         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1220                 if (copy_from_user(&ifr, argp, ifreq_len))
1221                         return -EFAULT;
1222
1223         if (cmd == TUNGETFEATURES) {
1224                 /* Currently this just means: "what IFF flags are valid?".
1225                  * This is needed because we never checked for invalid flags on
1226                  * TUNSETIFF. */
1227                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1228                                 IFF_VNET_HDR,
1229                                 (unsigned int __user*)argp);
1230         }
1231
1232         rtnl_lock();
1233
1234         tun = __tun_get(tfile);
1235         if (cmd == TUNSETIFF && !tun) {
1236                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1237
1238                 ret = tun_set_iff(tfile->net, file, &ifr);
1239
1240                 if (ret)
1241                         goto unlock;
1242
1243                 if (copy_to_user(argp, &ifr, ifreq_len))
1244                         ret = -EFAULT;
1245                 goto unlock;
1246         }
1247
1248         ret = -EBADFD;
1249         if (!tun)
1250                 goto unlock;
1251
1252         tun_debug(KERN_INFO, tun, "tun_chr_ioctl cmd %d\n", cmd);
1253
1254         ret = 0;
1255         switch (cmd) {
1256         case TUNGETIFF:
1257                 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1258                 if (ret)
1259                         break;
1260
1261                 if (copy_to_user(argp, &ifr, ifreq_len))
1262                         ret = -EFAULT;
1263                 break;
1264
1265         case TUNSETNOCSUM:
1266                 /* Disable/Enable checksum */
1267
1268                 /* [unimplemented] */
1269                 tun_debug(KERN_INFO, tun, "ignored: set checksum %s\n",
1270                           arg ? "disabled" : "enabled");
1271                 break;
1272
1273         case TUNSETPERSIST:
1274                 /* Disable/Enable persist mode */
1275                 if (arg)
1276                         tun->flags |= TUN_PERSIST;
1277                 else
1278                         tun->flags &= ~TUN_PERSIST;
1279
1280                 tun_debug(KERN_INFO, tun, "persist %s\n",
1281                           arg ? "enabled" : "disabled");
1282                 break;
1283
1284         case TUNSETOWNER:
1285                 /* Set owner of the device */
1286                 tun->owner = (uid_t) arg;
1287
1288                 tun_debug(KERN_INFO, tun, "owner set to %d\n", tun->owner);
1289                 break;
1290
1291         case TUNSETGROUP:
1292                 /* Set group of the device */
1293                 tun->group= (gid_t) arg;
1294
1295                 tun_debug(KERN_INFO, tun, "group set to %d\n", tun->group);
1296                 break;
1297
1298         case TUNSETLINK:
1299                 /* Only allow setting the type when the interface is down */
1300                 if (tun->dev->flags & IFF_UP) {
1301                         tun_debug(KERN_INFO, tun,
1302                                   "Linktype set failed because interface is up\n");
1303                         ret = -EBUSY;
1304                 } else {
1305                         tun->dev->type = (int) arg;
1306                         tun_debug(KERN_INFO, tun, "linktype set to %d\n",
1307                                   tun->dev->type);
1308                         ret = 0;
1309                 }
1310                 break;
1311
1312 #ifdef TUN_DEBUG
1313         case TUNSETDEBUG:
1314                 tun->debug = arg;
1315                 break;
1316 #endif
1317         case TUNSETOFFLOAD:
1318                 ret = set_offload(tun, arg);
1319                 break;
1320
1321         case TUNSETTXFILTER:
1322                 /* Can be set only for TAPs */
1323                 ret = -EINVAL;
1324                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1325                         break;
1326                 ret = update_filter(&tun->txflt, (void __user *)arg);
1327                 break;
1328
1329         case SIOCGIFHWADDR:
1330                 /* Get hw address */
1331                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1332                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1333                 if (copy_to_user(argp, &ifr, ifreq_len))
1334                         ret = -EFAULT;
1335                 break;
1336
1337         case SIOCSIFHWADDR:
1338                 /* Set hw address */
1339                 tun_debug(KERN_DEBUG, tun, "set hw address: %pM\n",
1340                           ifr.ifr_hwaddr.sa_data);
1341
1342                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1343                 break;
1344
1345         case TUNGETSNDBUF:
1346                 sndbuf = tun->socket.sk->sk_sndbuf;
1347                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1348                         ret = -EFAULT;
1349                 break;
1350
1351         case TUNSETSNDBUF:
1352                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1353                         ret = -EFAULT;
1354                         break;
1355                 }
1356
1357                 tun->socket.sk->sk_sndbuf = sndbuf;
1358                 break;
1359
1360         case TUNGETVNETHDRSZ:
1361                 vnet_hdr_sz = tun->vnet_hdr_sz;
1362                 if (copy_to_user(argp, &vnet_hdr_sz, sizeof(vnet_hdr_sz)))
1363                         ret = -EFAULT;
1364                 break;
1365
1366         case TUNSETVNETHDRSZ:
1367                 if (copy_from_user(&vnet_hdr_sz, argp, sizeof(vnet_hdr_sz))) {
1368                         ret = -EFAULT;
1369                         break;
1370                 }
1371                 if (vnet_hdr_sz < (int)sizeof(struct virtio_net_hdr)) {
1372                         ret = -EINVAL;
1373                         break;
1374                 }
1375
1376                 tun->vnet_hdr_sz = vnet_hdr_sz;
1377                 break;
1378
1379         case TUNATTACHFILTER:
1380                 /* Can be set only for TAPs */
1381                 ret = -EINVAL;
1382                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1383                         break;
1384                 ret = -EFAULT;
1385                 if (copy_from_user(&fprog, argp, sizeof(fprog)))
1386                         break;
1387
1388                 ret = sk_attach_filter(&fprog, tun->socket.sk);
1389                 break;
1390
1391         case TUNDETACHFILTER:
1392                 /* Can be set only for TAPs */
1393                 ret = -EINVAL;
1394                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1395                         break;
1396                 ret = sk_detach_filter(tun->socket.sk);
1397                 break;
1398
1399         default:
1400                 ret = -EINVAL;
1401                 break;
1402         }
1403
1404 unlock:
1405         rtnl_unlock();
1406         if (tun)
1407                 tun_put(tun);
1408         return ret;
1409 }
1410
1411 static long tun_chr_ioctl(struct file *file,
1412                           unsigned int cmd, unsigned long arg)
1413 {
1414         return __tun_chr_ioctl(file, cmd, arg, sizeof (struct ifreq));
1415 }
1416
1417 #ifdef CONFIG_COMPAT
1418 static long tun_chr_compat_ioctl(struct file *file,
1419                          unsigned int cmd, unsigned long arg)
1420 {
1421         switch (cmd) {
1422         case TUNSETIFF:
1423         case TUNGETIFF:
1424         case TUNSETTXFILTER:
1425         case TUNGETSNDBUF:
1426         case TUNSETSNDBUF:
1427         case SIOCGIFHWADDR:
1428         case SIOCSIFHWADDR:
1429                 arg = (unsigned long)compat_ptr(arg);
1430                 break;
1431         default:
1432                 arg = (compat_ulong_t)arg;
1433                 break;
1434         }
1435
1436         /*
1437          * compat_ifreq is shorter than ifreq, so we must not access beyond
1438          * the end of that structure. All fields that are used in this
1439          * driver are compatible though, we don't need to convert the
1440          * contents.
1441          */
1442         return __tun_chr_ioctl(file, cmd, arg, sizeof(struct compat_ifreq));
1443 }
1444 #endif /* CONFIG_COMPAT */
1445
1446 static int tun_chr_fasync(int fd, struct file *file, int on)
1447 {
1448         struct tun_struct *tun = tun_get(file);
1449         int ret;
1450
1451         if (!tun)
1452                 return -EBADFD;
1453
1454         tun_debug(KERN_INFO, tun, "tun_chr_fasync %d\n", on);
1455
1456         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1457                 goto out;
1458
1459         if (on) {
1460                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1461                 if (ret)
1462                         goto out;
1463                 tun->flags |= TUN_FASYNC;
1464         } else
1465                 tun->flags &= ~TUN_FASYNC;
1466         ret = 0;
1467 out:
1468         tun_put(tun);
1469         return ret;
1470 }
1471
1472 static int tun_chr_open(struct inode *inode, struct file * file)
1473 {
1474         struct tun_file *tfile;
1475
1476         DBG1(KERN_INFO, "tunX: tun_chr_open\n");
1477
1478         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1479         if (!tfile)
1480                 return -ENOMEM;
1481         atomic_set(&tfile->count, 0);
1482         tfile->tun = NULL;
1483         tfile->net = get_net(current->nsproxy->net_ns);
1484         file->private_data = tfile;
1485         return 0;
1486 }
1487
1488 static int tun_chr_close(struct inode *inode, struct file *file)
1489 {
1490         struct tun_file *tfile = file->private_data;
1491         struct tun_struct *tun;
1492
1493         tun = __tun_get(tfile);
1494         if (tun) {
1495                 struct net_device *dev = tun->dev;
1496
1497                 tun_debug(KERN_INFO, tun, "tun_chr_close\n");
1498
1499                 __tun_detach(tun);
1500
1501                 /* If desirable, unregister the netdevice. */
1502                 if (!(tun->flags & TUN_PERSIST)) {
1503                         rtnl_lock();
1504                         if (dev->reg_state == NETREG_REGISTERED)
1505                                 unregister_netdevice(dev);
1506                         rtnl_unlock();
1507                 }
1508         }
1509
1510         tun = tfile->tun;
1511         if (tun)
1512                 sock_put(tun->socket.sk);
1513
1514         put_net(tfile->net);
1515         kfree(tfile);
1516
1517         return 0;
1518 }
1519
1520 static const struct file_operations tun_fops = {
1521         .owner  = THIS_MODULE,
1522         .llseek = no_llseek,
1523         .read  = do_sync_read,
1524         .aio_read  = tun_chr_aio_read,
1525         .write = do_sync_write,
1526         .aio_write = tun_chr_aio_write,
1527         .poll   = tun_chr_poll,
1528         .unlocked_ioctl = tun_chr_ioctl,
1529 #ifdef CONFIG_COMPAT
1530         .compat_ioctl = tun_chr_compat_ioctl,
1531 #endif
1532         .open   = tun_chr_open,
1533         .release = tun_chr_close,
1534         .fasync = tun_chr_fasync
1535 };
1536
1537 static struct miscdevice tun_miscdev = {
1538         .minor = TUN_MINOR,
1539         .name = "tun",
1540         .nodename = "net/tun",
1541         .fops = &tun_fops,
1542 };
1543
1544 /* ethtool interface */
1545
1546 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1547 {
1548         cmd->supported          = 0;
1549         cmd->advertising        = 0;
1550         ethtool_cmd_speed_set(cmd, SPEED_10);
1551         cmd->duplex             = DUPLEX_FULL;
1552         cmd->port               = PORT_TP;
1553         cmd->phy_address        = 0;
1554         cmd->transceiver        = XCVR_INTERNAL;
1555         cmd->autoneg            = AUTONEG_DISABLE;
1556         cmd->maxtxpkt           = 0;
1557         cmd->maxrxpkt           = 0;
1558         return 0;
1559 }
1560
1561 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1562 {
1563         struct tun_struct *tun = netdev_priv(dev);
1564
1565         strcpy(info->driver, DRV_NAME);
1566         strcpy(info->version, DRV_VERSION);
1567         strcpy(info->fw_version, "N/A");
1568
1569         switch (tun->flags & TUN_TYPE_MASK) {
1570         case TUN_TUN_DEV:
1571                 strcpy(info->bus_info, "tun");
1572                 break;
1573         case TUN_TAP_DEV:
1574                 strcpy(info->bus_info, "tap");
1575                 break;
1576         }
1577 }
1578
1579 static u32 tun_get_msglevel(struct net_device *dev)
1580 {
1581 #ifdef TUN_DEBUG
1582         struct tun_struct *tun = netdev_priv(dev);
1583         return tun->debug;
1584 #else
1585         return -EOPNOTSUPP;
1586 #endif
1587 }
1588
1589 static void tun_set_msglevel(struct net_device *dev, u32 value)
1590 {
1591 #ifdef TUN_DEBUG
1592         struct tun_struct *tun = netdev_priv(dev);
1593         tun->debug = value;
1594 #endif
1595 }
1596
1597 static const struct ethtool_ops tun_ethtool_ops = {
1598         .get_settings   = tun_get_settings,
1599         .get_drvinfo    = tun_get_drvinfo,
1600         .get_msglevel   = tun_get_msglevel,
1601         .set_msglevel   = tun_set_msglevel,
1602         .get_link       = ethtool_op_get_link,
1603 };
1604
1605
1606 static int __init tun_init(void)
1607 {
1608         int ret = 0;
1609
1610         pr_info("%s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1611         pr_info("%s\n", DRV_COPYRIGHT);
1612
1613         ret = rtnl_link_register(&tun_link_ops);
1614         if (ret) {
1615                 pr_err("Can't register link_ops\n");
1616                 goto err_linkops;
1617         }
1618
1619         ret = misc_register(&tun_miscdev);
1620         if (ret) {
1621                 pr_err("Can't register misc device %d\n", TUN_MINOR);
1622                 goto err_misc;
1623         }
1624         return  0;
1625 err_misc:
1626         rtnl_link_unregister(&tun_link_ops);
1627 err_linkops:
1628         return ret;
1629 }
1630
1631 static void tun_cleanup(void)
1632 {
1633         misc_deregister(&tun_miscdev);
1634         rtnl_link_unregister(&tun_link_ops);
1635 }
1636
1637 /* Get an underlying socket object from tun file.  Returns error unless file is
1638  * attached to a device.  The returned object works like a packet socket, it
1639  * can be used for sock_sendmsg/sock_recvmsg.  The caller is responsible for
1640  * holding a reference to the file for as long as the socket is in use. */
1641 struct socket *tun_get_socket(struct file *file)
1642 {
1643         struct tun_struct *tun;
1644         if (file->f_op != &tun_fops)
1645                 return ERR_PTR(-EINVAL);
1646         tun = tun_get(file);
1647         if (!tun)
1648                 return ERR_PTR(-EBADFD);
1649         tun_put(tun);
1650         return &tun->socket;
1651 }
1652 EXPORT_SYMBOL_GPL(tun_get_socket);
1653
1654 module_init(tun_init);
1655 module_exit(tun_cleanup);
1656 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1657 MODULE_AUTHOR(DRV_COPYRIGHT);
1658 MODULE_LICENSE("GPL");
1659 MODULE_ALIAS_MISCDEV(TUN_MINOR);
1660 MODULE_ALIAS("devname:net/tun");