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