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   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                                        const 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         int offset = 0;
 551
 552         if (!(tun->flags & TUN_NO_PI)) {
 553                 if ((len -= sizeof(pi)) > count)
 554                         return -EINVAL;
 555
 556                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 557                         return -EFAULT;
 558                 offset += sizeof(pi);
 559         }
 560
 561         if (tun->flags & TUN_VNET_HDR) {
 562                 if ((len -= sizeof(gso)) > count)
 563                         return -EINVAL;
 564
 565                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 566                         return -EFAULT;
 567
 568                 if (gso.hdr_len > len)
 569                         return -EINVAL;
 570                 offset += sizeof(pi);
 571         }
 572
 573         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 574                 align = NET_IP_ALIGN;
 575                 if (unlikely(len < ETH_HLEN ||
 576                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 577                         return -EINVAL;
 578         }
 579
 580         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 581         if (IS_ERR(skb)) {
 582                 if (PTR_ERR(skb) != -EAGAIN)
 583                         tun->dev->stats.rx_dropped++;
 584                 return PTR_ERR(skb);
 585         }
 586
 587         if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
 588                 tun->dev->stats.rx_dropped++;
 589                 kfree_skb(skb);
 590                 return -EFAULT;
 591         }
 592
 593         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 594                 if (!skb_partial_csum_set(skb, gso.csum_start,
 595                                           gso.csum_offset)) {
 596                         tun->dev->stats.rx_frame_errors++;
 597                         kfree_skb(skb);
 598                         return -EINVAL;
 599                 }
 600         } else if (tun->flags & TUN_NOCHECKSUM)
 601                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 602
 603         switch (tun->flags & TUN_TYPE_MASK) {
 604         case TUN_TUN_DEV:
 605                 if (tun->flags & TUN_NO_PI) {
 606                         switch (skb->data[0] & 0xf0) {
 607                         case 0x40:
 608                                 pi.proto = htons(ETH_P_IP);
 609                                 break;
 610                         case 0x60:
 611                                 pi.proto = htons(ETH_P_IPV6);
 612                                 break;
 613                         default:
 614                                 tun->dev->stats.rx_dropped++;
 615                                 kfree_skb(skb);
 616                                 return -EINVAL;
 617                         }
 618                 }
 619
 620                 skb_reset_mac_header(skb);
 621                 skb->protocol = pi.proto;
 622                 skb->dev = tun->dev;
 623                 break;
 624         case TUN_TAP_DEV:
 625                 skb->protocol = eth_type_trans(skb, tun->dev);
 626                 break;
 627         };
 628
 629         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 630                 pr_debug("GSO!\n");
 631                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 632                 case VIRTIO_NET_HDR_GSO_TCPV4:
 633                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 634                         break;
 635                 case VIRTIO_NET_HDR_GSO_TCPV6:
 636                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 637                         break;
 638                 default:
 639                         tun->dev->stats.rx_frame_errors++;
 640                         kfree_skb(skb);
 641                         return -EINVAL;
 642                 }
 643
 644                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 645                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 646
 647                 skb_shinfo(skb)->gso_size = gso.gso_size;
 648                 if (skb_shinfo(skb)->gso_size == 0) {
 649                         tun->dev->stats.rx_frame_errors++;
 650                         kfree_skb(skb);
 651                         return -EINVAL;
 652                 }
 653
 654                 /* Header must be checked, and gso_segs computed. */
 655                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 656                 skb_shinfo(skb)->gso_segs = 0;
 657         }
 658
 659         netif_rx_ni(skb);
 660
 661         tun->dev->stats.rx_packets++;
 662         tun->dev->stats.rx_bytes += len;
 663
 664         return count;
 665 }
 666
 667 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 668                               unsigned long count, loff_t pos)
 669 {
 670         struct file *file = iocb->ki_filp;
 671         struct tun_struct *tun = tun_get(file);
 672         ssize_t result;
 673
 674         if (!tun)
 675                 return -EBADFD;
 676
 677         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 678
 679         result = tun_get_user(tun, iv, iov_length(iv, count),
 680                               file->f_flags & O_NONBLOCK);
 681
 682         tun_put(tun);
 683         return result;
 684 }
 685
 686 /* Put packet to the user space buffer */
 687 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 688                                        struct sk_buff *skb,
 689                                        const struct iovec *iv, int len)
 690 {
 691         struct tun_pi pi = { 0, skb->protocol };
 692         ssize_t total = 0;
 693
 694         if (!(tun->flags & TUN_NO_PI)) {
 695                 if ((len -= sizeof(pi)) < 0)
 696                         return -EINVAL;
 697
 698                 if (len < skb->len) {
 699                         /* Packet will be striped */
 700                         pi.flags |= TUN_PKT_STRIP;
 701                 }
 702
 703                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 704                         return -EFAULT;
 705                 total += sizeof(pi);
 706         }
 707
 708         if (tun->flags & TUN_VNET_HDR) {
 709                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 710                 if ((len -= sizeof(gso)) < 0)
 711                         return -EINVAL;
 712
 713                 if (skb_is_gso(skb)) {
 714                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 715
 716                         /* This is a hint as to how much should be linear. */
 717                         gso.hdr_len = skb_headlen(skb);
 718                         gso.gso_size = sinfo->gso_size;
 719                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 720                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 721                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 722                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 723                         else
 724                                 BUG();
 725                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 726                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 727                 } else
 728                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 729
 730                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 731                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 732                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 733                         gso.csum_offset = skb->csum_offset;
 734                 } /* else everything is zero */
 735
 736                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 737                                                sizeof(gso))))
 738                         return -EFAULT;
 739                 total += sizeof(gso);
 740         }
 741
 742         len = min_t(int, skb->len, len);
 743
 744         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 745         total += len;
 746
 747         tun->dev->stats.tx_packets++;
 748         tun->dev->stats.tx_bytes += len;
 749
 750         return total;
 751 }
 752
 753 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 754                             unsigned long count, loff_t pos)
 755 {
 756         struct file *file = iocb->ki_filp;
 757         struct tun_file *tfile = file->private_data;
 758         struct tun_struct *tun = __tun_get(tfile);
 759         DECLARE_WAITQUEUE(wait, current);
 760         struct sk_buff *skb;
 761         ssize_t len, ret = 0;
 762
 763         if (!tun)
 764                 return -EBADFD;
 765
 766         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 767
 768         len = iov_length(iv, count);
 769         if (len < 0) {
 770                 ret = -EINVAL;
 771                 goto out;
 772         }
 773
 774         add_wait_queue(&tun->socket.wait, &wait);
 775         while (len) {
 776                 current->state = TASK_INTERRUPTIBLE;
 777
 778                 /* Read frames from the queue */
 779                 if (!(skb=skb_dequeue(&tun->readq))) {
 780                         if (file->f_flags & O_NONBLOCK) {
 781                                 ret = -EAGAIN;
 782                                 break;
 783                         }
 784                         if (signal_pending(current)) {
 785                                 ret = -ERESTARTSYS;
 786                                 break;
 787                         }
 788                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 789                                 ret = -EIO;
 790                                 break;
 791                         }
 792
 793                         /* Nothing to read, let's sleep */
 794                         schedule();
 795                         continue;
 796                 }
 797                 netif_wake_queue(tun->dev);
 798
 799                 ret = tun_put_user(tun, skb, iv, len);
 800                 kfree_skb(skb);
 801                 break;
 802         }
 803
 804         current->state = TASK_RUNNING;
 805         remove_wait_queue(&tun->socket.wait, &wait);
 806
 807 out:
 808         tun_put(tun);
 809         return ret;
 810 }
 811
 812 static void tun_setup(struct net_device *dev)
 813 {
 814         struct tun_struct *tun = netdev_priv(dev);
 815
 816         skb_queue_head_init(&tun->readq);
 817
 818         tun->owner = -1;
 819         tun->group = -1;
 820
 821         dev->ethtool_ops = &tun_ethtool_ops;
 822         dev->destructor = tun_free_netdev;
 823 }
 824
 825 /* Trivial set of netlink ops to allow deleting tun or tap
 826  * device with netlink.
 827  */
 828 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 829 {
 830         return -EINVAL;
 831 }
 832
 833 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 834         .kind           = DRV_NAME,
 835         .priv_size      = sizeof(struct tun_struct),
 836         .setup          = tun_setup,
 837         .validate       = tun_validate,
 838 };
 839
 840 static void tun_sock_write_space(struct sock *sk)
 841 {
 842         struct tun_struct *tun;
 843
 844         if (!sock_writeable(sk))
 845                 return;
 846
 847         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 848                 wake_up_interruptible_sync(sk->sk_sleep);
 849
 850         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 851                 return;
 852
 853         tun = container_of(sk, struct tun_sock, sk)->tun;
 854         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 855 }
 856
 857 static void tun_sock_destruct(struct sock *sk)
 858 {
 859         free_netdev(container_of(sk, struct tun_sock, sk)->tun->dev);
 860 }
 861
 862 static struct proto tun_proto = {
 863         .name           = "tun",
 864         .owner          = THIS_MODULE,
 865         .obj_size       = sizeof(struct tun_sock),
 866 };
 867
 868 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 869 {
 870         struct sock *sk;
 871         struct tun_struct *tun;
 872         struct net_device *dev;
 873         int err;
 874
 875         dev = __dev_get_by_name(net, ifr->ifr_name);
 876         if (dev) {
 877                 if (ifr->ifr_flags & IFF_TUN_EXCL)
 878                         return -EBUSY;
 879                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 880                         tun = netdev_priv(dev);
 881                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
 882                         tun = netdev_priv(dev);
 883                 else
 884                         return -EINVAL;
 885
 886                 err = tun_attach(tun, file);
 887                 if (err < 0)
 888                         return err;
 889         }
 890         else {
 891                 char *name;
 892                 unsigned long flags = 0;
 893
 894                 err = -EINVAL;
 895
 896                 if (!capable(CAP_NET_ADMIN))
 897                         return -EPERM;
 898
 899                 /* Set dev type */
 900                 if (ifr->ifr_flags & IFF_TUN) {
 901                         /* TUN device */
 902                         flags |= TUN_TUN_DEV;
 903                         name = "tun%d";
 904                 } else if (ifr->ifr_flags & IFF_TAP) {
 905                         /* TAP device */
 906                         flags |= TUN_TAP_DEV;
 907                         name = "tap%d";
 908                 } else
 909                         goto failed;
 910
 911                 if (*ifr->ifr_name)
 912                         name = ifr->ifr_name;
 913
 914                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 915                                    tun_setup);
 916                 if (!dev)
 917                         return -ENOMEM;
 918
 919                 dev_net_set(dev, net);
 920                 dev->rtnl_link_ops = &tun_link_ops;
 921
 922                 tun = netdev_priv(dev);
 923                 tun->dev = dev;
 924                 tun->flags = flags;
 925                 tun->txflt.count = 0;
 926
 927                 err = -ENOMEM;
 928                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
 929                 if (!sk)
 930                         goto err_free_dev;
 931
 932                 init_waitqueue_head(&tun->socket.wait);
 933                 sock_init_data(&tun->socket, sk);
 934                 sk->sk_write_space = tun_sock_write_space;
 935                 sk->sk_sndbuf = INT_MAX;
 936
 937                 tun->sk = sk;
 938                 container_of(sk, struct tun_sock, sk)->tun = tun;
 939
 940                 tun_net_init(dev);
 941
 942                 if (strchr(dev->name, '%')) {
 943                         err = dev_alloc_name(dev, dev->name);
 944                         if (err < 0)
 945                                 goto err_free_sk;
 946                 }
 947
 948                 err = -EINVAL;
 949                 err = register_netdevice(tun->dev);
 950                 if (err < 0)
 951                         goto err_free_sk;
 952
 953                 sk->sk_destruct = tun_sock_destruct;
 954
 955                 err = tun_attach(tun, file);
 956                 if (err < 0)
 957                         goto failed;
 958         }
 959
 960         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
 961
 962         if (ifr->ifr_flags & IFF_NO_PI)
 963                 tun->flags |= TUN_NO_PI;
 964         else
 965                 tun->flags &= ~TUN_NO_PI;
 966
 967         if (ifr->ifr_flags & IFF_ONE_QUEUE)
 968                 tun->flags |= TUN_ONE_QUEUE;
 969         else
 970                 tun->flags &= ~TUN_ONE_QUEUE;
 971
 972         if (ifr->ifr_flags & IFF_VNET_HDR)
 973                 tun->flags |= TUN_VNET_HDR;
 974         else
 975                 tun->flags &= ~TUN_VNET_HDR;
 976
 977         /* Make sure persistent devices do not get stuck in
 978          * xoff state.
 979          */
 980         if (netif_running(tun->dev))
 981                 netif_wake_queue(tun->dev);
 982
 983         strcpy(ifr->ifr_name, tun->dev->name);
 984         return 0;
 985
 986  err_free_sk:
 987         sock_put(sk);
 988  err_free_dev:
 989         free_netdev(dev);
 990  failed:
 991         return err;
 992 }
 993
 994 static int tun_get_iff(struct net *net, struct file *file, struct ifreq *ifr)
 995 {
 996         struct tun_struct *tun = tun_get(file);
 997
 998         if (!tun)
 999                 return -EBADFD;
1000
1001         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
1002
1003         strcpy(ifr->ifr_name, tun->dev->name);
1004
1005         ifr->ifr_flags = 0;
1006
1007         if (ifr->ifr_flags & TUN_TUN_DEV)
1008                 ifr->ifr_flags |= IFF_TUN;
1009         else
1010                 ifr->ifr_flags |= IFF_TAP;
1011
1012         if (tun->flags & TUN_NO_PI)
1013                 ifr->ifr_flags |= IFF_NO_PI;
1014
1015         if (tun->flags & TUN_ONE_QUEUE)
1016                 ifr->ifr_flags |= IFF_ONE_QUEUE;
1017
1018         if (tun->flags & TUN_VNET_HDR)
1019                 ifr->ifr_flags |= IFF_VNET_HDR;
1020
1021         tun_put(tun);
1022         return 0;
1023 }
1024
1025 /* This is like a cut-down ethtool ops, except done via tun fd so no
1026  * privs required. */
1027 static int set_offload(struct net_device *dev, unsigned long arg)
1028 {
1029         unsigned int old_features, features;
1030
1031         old_features = dev->features;
1032         /* Unset features, set them as we chew on the arg. */
1033         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1034                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6));
1035
1036         if (arg & TUN_F_CSUM) {
1037                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1038                 arg &= ~TUN_F_CSUM;
1039
1040                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1041                         if (arg & TUN_F_TSO_ECN) {
1042                                 features |= NETIF_F_TSO_ECN;
1043                                 arg &= ~TUN_F_TSO_ECN;
1044                         }
1045                         if (arg & TUN_F_TSO4)
1046                                 features |= NETIF_F_TSO;
1047                         if (arg & TUN_F_TSO6)
1048                                 features |= NETIF_F_TSO6;
1049                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1050                 }
1051         }
1052
1053         /* This gives the user a way to test for new features in future by
1054          * trying to set them. */
1055         if (arg)
1056                 return -EINVAL;
1057
1058         dev->features = features;
1059         if (old_features != dev->features)
1060                 netdev_features_change(dev);
1061
1062         return 0;
1063 }
1064
1065 static int tun_chr_ioctl(struct inode *inode, struct file *file,
1066                          unsigned int cmd, unsigned long arg)
1067 {
1068         struct tun_file *tfile = file->private_data;
1069         struct tun_struct *tun;
1070         void __user* argp = (void __user*)arg;
1071         struct ifreq ifr;
1072         int sndbuf;
1073         int ret;
1074
1075         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1076                 if (copy_from_user(&ifr, argp, sizeof ifr))
1077                         return -EFAULT;
1078
1079         if (cmd == TUNGETFEATURES) {
1080                 /* Currently this just means: "what IFF flags are valid?".
1081                  * This is needed because we never checked for invalid flags on
1082                  * TUNSETIFF. */
1083                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1084                                 IFF_VNET_HDR,
1085                                 (unsigned int __user*)argp);
1086         }
1087
1088         tun = __tun_get(tfile);
1089         if (cmd == TUNSETIFF && !tun) {
1090                 int err;
1091
1092                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1093
1094                 rtnl_lock();
1095                 err = tun_set_iff(tfile->net, file, &ifr);
1096                 rtnl_unlock();
1097
1098                 if (err)
1099                         return err;
1100
1101                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1102                         return -EFAULT;
1103                 return 0;
1104         }
1105
1106
1107         if (!tun)
1108                 return -EBADFD;
1109
1110         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1111
1112         ret = 0;
1113         switch (cmd) {
1114         case TUNGETIFF:
1115                 ret = tun_get_iff(current->nsproxy->net_ns, file, &ifr);
1116                 if (ret)
1117                         break;
1118
1119                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1120                         ret = -EFAULT;
1121                 break;
1122
1123         case TUNSETNOCSUM:
1124                 /* Disable/Enable checksum */
1125                 if (arg)
1126                         tun->flags |= TUN_NOCHECKSUM;
1127                 else
1128                         tun->flags &= ~TUN_NOCHECKSUM;
1129
1130                 DBG(KERN_INFO "%s: checksum %s\n",
1131                     tun->dev->name, arg ? "disabled" : "enabled");
1132                 break;
1133
1134         case TUNSETPERSIST:
1135                 /* Disable/Enable persist mode */
1136                 if (arg)
1137                         tun->flags |= TUN_PERSIST;
1138                 else
1139                         tun->flags &= ~TUN_PERSIST;
1140
1141                 DBG(KERN_INFO "%s: persist %s\n",
1142                     tun->dev->name, arg ? "enabled" : "disabled");
1143                 break;
1144
1145         case TUNSETOWNER:
1146                 /* Set owner of the device */
1147                 tun->owner = (uid_t) arg;
1148
1149                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1150                 break;
1151
1152         case TUNSETGROUP:
1153                 /* Set group of the device */
1154                 tun->group= (gid_t) arg;
1155
1156                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1157                 break;
1158
1159         case TUNSETLINK:
1160                 /* Only allow setting the type when the interface is down */
1161                 rtnl_lock();
1162                 if (tun->dev->flags & IFF_UP) {
1163                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1164                                 tun->dev->name);
1165                         ret = -EBUSY;
1166                 } else {
1167                         tun->dev->type = (int) arg;
1168                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1169                         ret = 0;
1170                 }
1171                 rtnl_unlock();
1172                 break;
1173
1174 #ifdef TUN_DEBUG
1175         case TUNSETDEBUG:
1176                 tun->debug = arg;
1177                 break;
1178 #endif
1179         case TUNSETOFFLOAD:
1180                 rtnl_lock();
1181                 ret = set_offload(tun->dev, arg);
1182                 rtnl_unlock();
1183                 break;
1184
1185         case TUNSETTXFILTER:
1186                 /* Can be set only for TAPs */
1187                 ret = -EINVAL;
1188                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1189                         break;
1190                 rtnl_lock();
1191                 ret = update_filter(&tun->txflt, (void __user *)arg);
1192                 rtnl_unlock();
1193                 break;
1194
1195         case SIOCGIFHWADDR:
1196                 /* Get hw addres */
1197                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1198                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1199                 if (copy_to_user(argp, &ifr, sizeof ifr))
1200                         ret = -EFAULT;
1201                 break;
1202
1203         case SIOCSIFHWADDR:
1204                 /* Set hw address */
1205                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1206                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1207
1208                 rtnl_lock();
1209                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1210                 rtnl_unlock();
1211                 break;
1212
1213         case TUNGETSNDBUF:
1214                 sndbuf = tun->sk->sk_sndbuf;
1215                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1216                         ret = -EFAULT;
1217                 break;
1218
1219         case TUNSETSNDBUF:
1220                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1221                         ret = -EFAULT;
1222                         break;
1223                 }
1224
1225                 tun->sk->sk_sndbuf = sndbuf;
1226                 break;
1227
1228         default:
1229                 ret = -EINVAL;
1230                 break;
1231         };
1232
1233         tun_put(tun);
1234         return ret;
1235 }
1236
1237 static int tun_chr_fasync(int fd, struct file *file, int on)
1238 {
1239         struct tun_struct *tun = tun_get(file);
1240         int ret;
1241
1242         if (!tun)
1243                 return -EBADFD;
1244
1245         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1246
1247         lock_kernel();
1248         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1249                 goto out;
1250
1251         if (on) {
1252                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1253                 if (ret)
1254                         goto out;
1255                 tun->flags |= TUN_FASYNC;
1256         } else
1257                 tun->flags &= ~TUN_FASYNC;
1258         ret = 0;
1259 out:
1260         unlock_kernel();
1261         tun_put(tun);
1262         return ret;
1263 }
1264
1265 static int tun_chr_open(struct inode *inode, struct file * file)
1266 {
1267         struct tun_file *tfile;
1268         cycle_kernel_lock();
1269         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1270
1271         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1272         if (!tfile)
1273                 return -ENOMEM;
1274         atomic_set(&tfile->count, 0);
1275         tfile->tun = NULL;
1276         tfile->net = get_net(current->nsproxy->net_ns);
1277         file->private_data = tfile;
1278         return 0;
1279 }
1280
1281 static int tun_chr_close(struct inode *inode, struct file *file)
1282 {
1283         struct tun_file *tfile = file->private_data;
1284         struct tun_struct *tun = __tun_get(tfile);
1285
1286
1287         if (tun) {
1288                 DBG(KERN_INFO "%s: tun_chr_close\n", tun->dev->name);
1289
1290                 rtnl_lock();
1291                 __tun_detach(tun);
1292
1293                 /* If desireable, unregister the netdevice. */
1294                 if (!(tun->flags & TUN_PERSIST))
1295                         unregister_netdevice(tun->dev);
1296
1297                 rtnl_unlock();
1298         }
1299
1300         tun = tfile->tun;
1301         if (tun)
1302                 sock_put(tun->sk);
1303
1304         put_net(tfile->net);
1305         kfree(tfile);
1306
1307         return 0;
1308 }
1309
1310 static const struct file_operations tun_fops = {
1311         .owner  = THIS_MODULE,
1312         .llseek = no_llseek,
1313         .read  = do_sync_read,
1314         .aio_read  = tun_chr_aio_read,
1315         .write = do_sync_write,
1316         .aio_write = tun_chr_aio_write,
1317         .poll   = tun_chr_poll,
1318         .ioctl  = tun_chr_ioctl,
1319         .open   = tun_chr_open,
1320         .release = tun_chr_close,
1321         .fasync = tun_chr_fasync
1322 };
1323
1324 static struct miscdevice tun_miscdev = {
1325         .minor = TUN_MINOR,
1326         .name = "tun",
1327         .fops = &tun_fops,
1328 };
1329
1330 /* ethtool interface */
1331
1332 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1333 {
1334         cmd->supported          = 0;
1335         cmd->advertising        = 0;
1336         cmd->speed              = SPEED_10;
1337         cmd->duplex             = DUPLEX_FULL;
1338         cmd->port               = PORT_TP;
1339         cmd->phy_address        = 0;
1340         cmd->transceiver        = XCVR_INTERNAL;
1341         cmd->autoneg            = AUTONEG_DISABLE;
1342         cmd->maxtxpkt           = 0;
1343         cmd->maxrxpkt           = 0;
1344         return 0;
1345 }
1346
1347 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1348 {
1349         struct tun_struct *tun = netdev_priv(dev);
1350
1351         strcpy(info->driver, DRV_NAME);
1352         strcpy(info->version, DRV_VERSION);
1353         strcpy(info->fw_version, "N/A");
1354
1355         switch (tun->flags & TUN_TYPE_MASK) {
1356         case TUN_TUN_DEV:
1357                 strcpy(info->bus_info, "tun");
1358                 break;
1359         case TUN_TAP_DEV:
1360                 strcpy(info->bus_info, "tap");
1361                 break;
1362         }
1363 }
1364
1365 static u32 tun_get_msglevel(struct net_device *dev)
1366 {
1367 #ifdef TUN_DEBUG
1368         struct tun_struct *tun = netdev_priv(dev);
1369         return tun->debug;
1370 #else
1371         return -EOPNOTSUPP;
1372 #endif
1373 }
1374
1375 static void tun_set_msglevel(struct net_device *dev, u32 value)
1376 {
1377 #ifdef TUN_DEBUG
1378         struct tun_struct *tun = netdev_priv(dev);
1379         tun->debug = value;
1380 #endif
1381 }
1382
1383 static u32 tun_get_link(struct net_device *dev)
1384 {
1385         struct tun_struct *tun = netdev_priv(dev);
1386         return !!tun->tfile;
1387 }
1388
1389 static u32 tun_get_rx_csum(struct net_device *dev)
1390 {
1391         struct tun_struct *tun = netdev_priv(dev);
1392         return (tun->flags & TUN_NOCHECKSUM) == 0;
1393 }
1394
1395 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1396 {
1397         struct tun_struct *tun = netdev_priv(dev);
1398         if (data)
1399                 tun->flags &= ~TUN_NOCHECKSUM;
1400         else
1401                 tun->flags |= TUN_NOCHECKSUM;
1402         return 0;
1403 }
1404
1405 static const struct ethtool_ops tun_ethtool_ops = {
1406         .get_settings   = tun_get_settings,
1407         .get_drvinfo    = tun_get_drvinfo,
1408         .get_msglevel   = tun_get_msglevel,
1409         .set_msglevel   = tun_set_msglevel,
1410         .get_link       = tun_get_link,
1411         .get_rx_csum    = tun_get_rx_csum,
1412         .set_rx_csum    = tun_set_rx_csum
1413 };
1414
1415
1416 static int __init tun_init(void)
1417 {
1418         int ret = 0;
1419
1420         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1421         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1422
1423         ret = rtnl_link_register(&tun_link_ops);
1424         if (ret) {
1425                 printk(KERN_ERR "tun: Can't register link_ops\n");
1426                 goto err_linkops;
1427         }
1428
1429         ret = misc_register(&tun_miscdev);
1430         if (ret) {
1431                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1432                 goto err_misc;
1433         }
1434         return  0;
1435 err_misc:
1436         rtnl_link_unregister(&tun_link_ops);
1437 err_linkops:
1438         return ret;
1439 }
1440
1441 static void tun_cleanup(void)
1442 {
1443         misc_deregister(&tun_miscdev);
1444         rtnl_link_unregister(&tun_link_ops);
1445 }
1446
1447 module_init(tun_init);
1448 module_exit(tun_cleanup);
1449 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1450 MODULE_AUTHOR(DRV_COPYRIGHT);
1451 MODULE_LICENSE("GPL");
1452 MODULE_ALIAS_MISCDEV(TUN_MINOR);