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