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 NETDEV_TX_OK;
 402
 403 drop:
 404         dev->stats.tx_dropped++;
 405         kfree_skb(skb);
 406         return NETDEV_TX_OK;
 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;
 490         unsigned int mask = 0;
 491
 492         if (!tun)
 493                 return POLLERR;
 494
 495         sk = tun->sk;
 496
 497         DBG(KERN_INFO "%s: tun_chr_poll\n", tun->dev->name);
 498
 499         poll_wait(file, &tun->socket.wait, wait);
 500
 501         if (!skb_queue_empty(&tun->readq))
 502                 mask |= POLLIN | POLLRDNORM;
 503
 504         if (sock_writeable(sk) ||
 505             (!test_and_set_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags) &&
 506              sock_writeable(sk)))
 507                 mask |= POLLOUT | POLLWRNORM;
 508
 509         if (tun->dev->reg_state != NETREG_REGISTERED)
 510                 mask = POLLERR;
 511
 512         tun_put(tun);
 513         return mask;
 514 }
 515
 516 /* prepad is the amount to reserve at front.  len is length after that.
 517  * linear is a hint as to how much to copy (usually headers). */
 518 static inline struct sk_buff *tun_alloc_skb(struct tun_struct *tun,
 519                                             size_t prepad, size_t len,
 520                                             size_t linear, int noblock)
 521 {
 522         struct sock *sk = tun->sk;
 523         struct sk_buff *skb;
 524         int err;
 525
 526         /* Under a page?  Don't bother with paged skb. */
 527         if (prepad + len < PAGE_SIZE || !linear)
 528                 linear = len;
 529
 530         skb = sock_alloc_send_pskb(sk, prepad + linear, len - linear, noblock,
 531                                    &err);
 532         if (!skb)
 533                 return ERR_PTR(err);
 534
 535         skb_reserve(skb, prepad);
 536         skb_put(skb, linear);
 537         skb->data_len = len - linear;
 538         skb->len += len - linear;
 539
 540         return skb;
 541 }
 542
 543 /* Get packet from user space buffer */
 544 static __inline__ ssize_t tun_get_user(struct tun_struct *tun,
 545                                        const struct iovec *iv, size_t count,
 546                                        int noblock)
 547 {
 548         struct tun_pi pi = { 0, cpu_to_be16(ETH_P_IP) };
 549         struct sk_buff *skb;
 550         size_t len = count, align = 0;
 551         struct virtio_net_hdr gso = { 0 };
 552         int offset = 0;
 553
 554         if (!(tun->flags & TUN_NO_PI)) {
 555                 if ((len -= sizeof(pi)) > count)
 556                         return -EINVAL;
 557
 558                 if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi)))
 559                         return -EFAULT;
 560                 offset += sizeof(pi);
 561         }
 562
 563         if (tun->flags & TUN_VNET_HDR) {
 564                 if ((len -= sizeof(gso)) > count)
 565                         return -EINVAL;
 566
 567                 if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso)))
 568                         return -EFAULT;
 569
 570                 if ((gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
 571                     gso.csum_start + gso.csum_offset + 2 > gso.hdr_len)
 572                         gso.hdr_len = gso.csum_start + gso.csum_offset + 2;
 573
 574                 if (gso.hdr_len > len)
 575                         return -EINVAL;
 576                 offset += sizeof(gso);
 577         }
 578
 579         if ((tun->flags & TUN_TYPE_MASK) == TUN_TAP_DEV) {
 580                 align = NET_IP_ALIGN;
 581                 if (unlikely(len < ETH_HLEN ||
 582                              (gso.hdr_len && gso.hdr_len < ETH_HLEN)))
 583                         return -EINVAL;
 584         }
 585
 586         skb = tun_alloc_skb(tun, align, len, gso.hdr_len, noblock);
 587         if (IS_ERR(skb)) {
 588                 if (PTR_ERR(skb) != -EAGAIN)
 589                         tun->dev->stats.rx_dropped++;
 590                 return PTR_ERR(skb);
 591         }
 592
 593         if (skb_copy_datagram_from_iovec(skb, 0, iv, offset, len)) {
 594                 tun->dev->stats.rx_dropped++;
 595                 kfree_skb(skb);
 596                 return -EFAULT;
 597         }
 598
 599         if (gso.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 600                 if (!skb_partial_csum_set(skb, gso.csum_start,
 601                                           gso.csum_offset)) {
 602                         tun->dev->stats.rx_frame_errors++;
 603                         kfree_skb(skb);
 604                         return -EINVAL;
 605                 }
 606         } else if (tun->flags & TUN_NOCHECKSUM)
 607                 skb->ip_summed = CHECKSUM_UNNECESSARY;
 608
 609         switch (tun->flags & TUN_TYPE_MASK) {
 610         case TUN_TUN_DEV:
 611                 if (tun->flags & TUN_NO_PI) {
 612                         switch (skb->data[0] & 0xf0) {
 613                         case 0x40:
 614                                 pi.proto = htons(ETH_P_IP);
 615                                 break;
 616                         case 0x60:
 617                                 pi.proto = htons(ETH_P_IPV6);
 618                                 break;
 619                         default:
 620                                 tun->dev->stats.rx_dropped++;
 621                                 kfree_skb(skb);
 622                                 return -EINVAL;
 623                         }
 624                 }
 625
 626                 skb_reset_mac_header(skb);
 627                 skb->protocol = pi.proto;
 628                 skb->dev = tun->dev;
 629                 break;
 630         case TUN_TAP_DEV:
 631                 skb->protocol = eth_type_trans(skb, tun->dev);
 632                 break;
 633         };
 634
 635         if (gso.gso_type != VIRTIO_NET_HDR_GSO_NONE) {
 636                 pr_debug("GSO!\n");
 637                 switch (gso.gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
 638                 case VIRTIO_NET_HDR_GSO_TCPV4:
 639                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 640                         break;
 641                 case VIRTIO_NET_HDR_GSO_TCPV6:
 642                         skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
 643                         break;
 644                 case VIRTIO_NET_HDR_GSO_UDP:
 645                         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
 646                         break;
 647                 default:
 648                         tun->dev->stats.rx_frame_errors++;
 649                         kfree_skb(skb);
 650                         return -EINVAL;
 651                 }
 652
 653                 if (gso.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 654                         skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 655
 656                 skb_shinfo(skb)->gso_size = gso.gso_size;
 657                 if (skb_shinfo(skb)->gso_size == 0) {
 658                         tun->dev->stats.rx_frame_errors++;
 659                         kfree_skb(skb);
 660                         return -EINVAL;
 661                 }
 662
 663                 /* Header must be checked, and gso_segs computed. */
 664                 skb_shinfo(skb)->gso_type |= SKB_GSO_DODGY;
 665                 skb_shinfo(skb)->gso_segs = 0;
 666         }
 667
 668         netif_rx_ni(skb);
 669
 670         tun->dev->stats.rx_packets++;
 671         tun->dev->stats.rx_bytes += len;
 672
 673         return count;
 674 }
 675
 676 static ssize_t tun_chr_aio_write(struct kiocb *iocb, const struct iovec *iv,
 677                               unsigned long count, loff_t pos)
 678 {
 679         struct file *file = iocb->ki_filp;
 680         struct tun_struct *tun = tun_get(file);
 681         ssize_t result;
 682
 683         if (!tun)
 684                 return -EBADFD;
 685
 686         DBG(KERN_INFO "%s: tun_chr_write %ld\n", tun->dev->name, count);
 687
 688         result = tun_get_user(tun, iv, iov_length(iv, count),
 689                               file->f_flags & O_NONBLOCK);
 690
 691         tun_put(tun);
 692         return result;
 693 }
 694
 695 /* Put packet to the user space buffer */
 696 static __inline__ ssize_t tun_put_user(struct tun_struct *tun,
 697                                        struct sk_buff *skb,
 698                                        const struct iovec *iv, int len)
 699 {
 700         struct tun_pi pi = { 0, skb->protocol };
 701         ssize_t total = 0;
 702
 703         if (!(tun->flags & TUN_NO_PI)) {
 704                 if ((len -= sizeof(pi)) < 0)
 705                         return -EINVAL;
 706
 707                 if (len < skb->len) {
 708                         /* Packet will be striped */
 709                         pi.flags |= TUN_PKT_STRIP;
 710                 }
 711
 712                 if (memcpy_toiovecend(iv, (void *) &pi, 0, sizeof(pi)))
 713                         return -EFAULT;
 714                 total += sizeof(pi);
 715         }
 716
 717         if (tun->flags & TUN_VNET_HDR) {
 718                 struct virtio_net_hdr gso = { 0 }; /* no info leak */
 719                 if ((len -= sizeof(gso)) < 0)
 720                         return -EINVAL;
 721
 722                 if (skb_is_gso(skb)) {
 723                         struct skb_shared_info *sinfo = skb_shinfo(skb);
 724
 725                         /* This is a hint as to how much should be linear. */
 726                         gso.hdr_len = skb_headlen(skb);
 727                         gso.gso_size = sinfo->gso_size;
 728                         if (sinfo->gso_type & SKB_GSO_TCPV4)
 729                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 730                         else if (sinfo->gso_type & SKB_GSO_TCPV6)
 731                                 gso.gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
 732                         else if (sinfo->gso_type & SKB_GSO_UDP)
 733                                 gso.gso_type = VIRTIO_NET_HDR_GSO_UDP;
 734                         else
 735                                 BUG();
 736                         if (sinfo->gso_type & SKB_GSO_TCP_ECN)
 737                                 gso.gso_type |= VIRTIO_NET_HDR_GSO_ECN;
 738                 } else
 739                         gso.gso_type = VIRTIO_NET_HDR_GSO_NONE;
 740
 741                 if (skb->ip_summed == CHECKSUM_PARTIAL) {
 742                         gso.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
 743                         gso.csum_start = skb->csum_start - skb_headroom(skb);
 744                         gso.csum_offset = skb->csum_offset;
 745                 } /* else everything is zero */
 746
 747                 if (unlikely(memcpy_toiovecend(iv, (void *)&gso, total,
 748                                                sizeof(gso))))
 749                         return -EFAULT;
 750                 total += sizeof(gso);
 751         }
 752
 753         len = min_t(int, skb->len, len);
 754
 755         skb_copy_datagram_const_iovec(skb, 0, iv, total, len);
 756         total += len;
 757
 758         tun->dev->stats.tx_packets++;
 759         tun->dev->stats.tx_bytes += len;
 760
 761         return total;
 762 }
 763
 764 static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 765                             unsigned long count, loff_t pos)
 766 {
 767         struct file *file = iocb->ki_filp;
 768         struct tun_file *tfile = file->private_data;
 769         struct tun_struct *tun = __tun_get(tfile);
 770         DECLARE_WAITQUEUE(wait, current);
 771         struct sk_buff *skb;
 772         ssize_t len, ret = 0;
 773
 774         if (!tun)
 775                 return -EBADFD;
 776
 777         DBG(KERN_INFO "%s: tun_chr_read\n", tun->dev->name);
 778
 779         len = iov_length(iv, count);
 780         if (len < 0) {
 781                 ret = -EINVAL;
 782                 goto out;
 783         }
 784
 785         add_wait_queue(&tun->socket.wait, &wait);
 786         while (len) {
 787                 current->state = TASK_INTERRUPTIBLE;
 788
 789                 /* Read frames from the queue */
 790                 if (!(skb=skb_dequeue(&tun->readq))) {
 791                         if (file->f_flags & O_NONBLOCK) {
 792                                 ret = -EAGAIN;
 793                                 break;
 794                         }
 795                         if (signal_pending(current)) {
 796                                 ret = -ERESTARTSYS;
 797                                 break;
 798                         }
 799                         if (tun->dev->reg_state != NETREG_REGISTERED) {
 800                                 ret = -EIO;
 801                                 break;
 802                         }
 803
 804                         /* Nothing to read, let's sleep */
 805                         schedule();
 806                         continue;
 807                 }
 808                 netif_wake_queue(tun->dev);
 809
 810                 ret = tun_put_user(tun, skb, iv, len);
 811                 kfree_skb(skb);
 812                 break;
 813         }
 814
 815         current->state = TASK_RUNNING;
 816         remove_wait_queue(&tun->socket.wait, &wait);
 817
 818 out:
 819         tun_put(tun);
 820         return ret;
 821 }
 822
 823 static void tun_setup(struct net_device *dev)
 824 {
 825         struct tun_struct *tun = netdev_priv(dev);
 826
 827         skb_queue_head_init(&tun->readq);
 828
 829         tun->owner = -1;
 830         tun->group = -1;
 831
 832         dev->ethtool_ops = &tun_ethtool_ops;
 833         dev->destructor = tun_free_netdev;
 834 }
 835
 836 /* Trivial set of netlink ops to allow deleting tun or tap
 837  * device with netlink.
 838  */
 839 static int tun_validate(struct nlattr *tb[], struct nlattr *data[])
 840 {
 841         return -EINVAL;
 842 }
 843
 844 static struct rtnl_link_ops tun_link_ops __read_mostly = {
 845         .kind           = DRV_NAME,
 846         .priv_size      = sizeof(struct tun_struct),
 847         .setup          = tun_setup,
 848         .validate       = tun_validate,
 849 };
 850
 851 static void tun_sock_write_space(struct sock *sk)
 852 {
 853         struct tun_struct *tun;
 854
 855         if (!sock_writeable(sk))
 856                 return;
 857
 858         if (!test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags))
 859                 return;
 860
 861         if (sk->sk_sleep && waitqueue_active(sk->sk_sleep))
 862                 wake_up_interruptible_sync(sk->sk_sleep);
 863
 864         tun = container_of(sk, struct tun_sock, sk)->tun;
 865         kill_fasync(&tun->fasync, SIGIO, POLL_OUT);
 866 }
 867
 868 static void tun_sock_destruct(struct sock *sk)
 869 {
 870         free_netdev(container_of(sk, struct tun_sock, sk)->tun->dev);
 871 }
 872
 873 static struct proto tun_proto = {
 874         .name           = "tun",
 875         .owner          = THIS_MODULE,
 876         .obj_size       = sizeof(struct tun_sock),
 877 };
 878
 879 static int tun_flags(struct tun_struct *tun)
 880 {
 881         int flags = 0;
 882
 883         if (tun->flags & TUN_TUN_DEV)
 884                 flags |= IFF_TUN;
 885         else
 886                 flags |= IFF_TAP;
 887
 888         if (tun->flags & TUN_NO_PI)
 889                 flags |= IFF_NO_PI;
 890
 891         if (tun->flags & TUN_ONE_QUEUE)
 892                 flags |= IFF_ONE_QUEUE;
 893
 894         if (tun->flags & TUN_VNET_HDR)
 895                 flags |= IFF_VNET_HDR;
 896
 897         return flags;
 898 }
 899
 900 static ssize_t tun_show_flags(struct device *dev, struct device_attribute *attr,
 901                               char *buf)
 902 {
 903         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 904         return sprintf(buf, "0x%x\n", tun_flags(tun));
 905 }
 906
 907 static ssize_t tun_show_owner(struct device *dev, struct device_attribute *attr,
 908                               char *buf)
 909 {
 910         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 911         return sprintf(buf, "%d\n", tun->owner);
 912 }
 913
 914 static ssize_t tun_show_group(struct device *dev, struct device_attribute *attr,
 915                               char *buf)
 916 {
 917         struct tun_struct *tun = netdev_priv(to_net_dev(dev));
 918         return sprintf(buf, "%d\n", tun->group);
 919 }
 920
 921 static DEVICE_ATTR(tun_flags, 0444, tun_show_flags, NULL);
 922 static DEVICE_ATTR(owner, 0444, tun_show_owner, NULL);
 923 static DEVICE_ATTR(group, 0444, tun_show_group, NULL);
 924
 925 static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr)
 926 {
 927         struct sock *sk;
 928         struct tun_struct *tun;
 929         struct net_device *dev;
 930         int err;
 931
 932         dev = __dev_get_by_name(net, ifr->ifr_name);
 933         if (dev) {
 934                 if (ifr->ifr_flags & IFF_TUN_EXCL)
 935                         return -EBUSY;
 936                 if ((ifr->ifr_flags & IFF_TUN) && dev->netdev_ops == &tun_netdev_ops)
 937                         tun = netdev_priv(dev);
 938                 else if ((ifr->ifr_flags & IFF_TAP) && dev->netdev_ops == &tap_netdev_ops)
 939                         tun = netdev_priv(dev);
 940                 else
 941                         return -EINVAL;
 942
 943                 err = tun_attach(tun, file);
 944                 if (err < 0)
 945                         return err;
 946         }
 947         else {
 948                 char *name;
 949                 unsigned long flags = 0;
 950
 951                 err = -EINVAL;
 952
 953                 if (!capable(CAP_NET_ADMIN))
 954                         return -EPERM;
 955
 956                 /* Set dev type */
 957                 if (ifr->ifr_flags & IFF_TUN) {
 958                         /* TUN device */
 959                         flags |= TUN_TUN_DEV;
 960                         name = "tun%d";
 961                 } else if (ifr->ifr_flags & IFF_TAP) {
 962                         /* TAP device */
 963                         flags |= TUN_TAP_DEV;
 964                         name = "tap%d";
 965                 } else
 966                         goto failed;
 967
 968                 if (*ifr->ifr_name)
 969                         name = ifr->ifr_name;
 970
 971                 dev = alloc_netdev(sizeof(struct tun_struct), name,
 972                                    tun_setup);
 973                 if (!dev)
 974                         return -ENOMEM;
 975
 976                 dev_net_set(dev, net);
 977                 dev->rtnl_link_ops = &tun_link_ops;
 978
 979                 tun = netdev_priv(dev);
 980                 tun->dev = dev;
 981                 tun->flags = flags;
 982                 tun->txflt.count = 0;
 983
 984                 err = -ENOMEM;
 985                 sk = sk_alloc(net, AF_UNSPEC, GFP_KERNEL, &tun_proto);
 986                 if (!sk)
 987                         goto err_free_dev;
 988
 989                 init_waitqueue_head(&tun->socket.wait);
 990                 sock_init_data(&tun->socket, sk);
 991                 sk->sk_write_space = tun_sock_write_space;
 992                 sk->sk_sndbuf = INT_MAX;
 993
 994                 tun->sk = sk;
 995                 container_of(sk, struct tun_sock, sk)->tun = tun;
 996
 997                 tun_net_init(dev);
 998
 999                 if (strchr(dev->name, '%')) {
1000                         err = dev_alloc_name(dev, dev->name);
1001                         if (err < 0)
1002                                 goto err_free_sk;
1003                 }
1004
1005                 err = register_netdevice(tun->dev);
1006                 if (err < 0)
1007                         goto err_free_sk;
1008
1009                 if (device_create_file(&tun->dev->dev, &dev_attr_tun_flags) ||
1010                     device_create_file(&tun->dev->dev, &dev_attr_owner) ||
1011                     device_create_file(&tun->dev->dev, &dev_attr_group))
1012                         printk(KERN_ERR "Failed to create tun sysfs files\n");
1013
1014                 sk->sk_destruct = tun_sock_destruct;
1015
1016                 err = tun_attach(tun, file);
1017                 if (err < 0)
1018                         goto failed;
1019         }
1020
1021         DBG(KERN_INFO "%s: tun_set_iff\n", tun->dev->name);
1022
1023         if (ifr->ifr_flags & IFF_NO_PI)
1024                 tun->flags |= TUN_NO_PI;
1025         else
1026                 tun->flags &= ~TUN_NO_PI;
1027
1028         if (ifr->ifr_flags & IFF_ONE_QUEUE)
1029                 tun->flags |= TUN_ONE_QUEUE;
1030         else
1031                 tun->flags &= ~TUN_ONE_QUEUE;
1032
1033         if (ifr->ifr_flags & IFF_VNET_HDR)
1034                 tun->flags |= TUN_VNET_HDR;
1035         else
1036                 tun->flags &= ~TUN_VNET_HDR;
1037
1038         /* Make sure persistent devices do not get stuck in
1039          * xoff state.
1040          */
1041         if (netif_running(tun->dev))
1042                 netif_wake_queue(tun->dev);
1043
1044         strcpy(ifr->ifr_name, tun->dev->name);
1045         return 0;
1046
1047  err_free_sk:
1048         sock_put(sk);
1049  err_free_dev:
1050         free_netdev(dev);
1051  failed:
1052         return err;
1053 }
1054
1055 static int tun_get_iff(struct net *net, struct tun_struct *tun,
1056                        struct ifreq *ifr)
1057 {
1058         DBG(KERN_INFO "%s: tun_get_iff\n", tun->dev->name);
1059
1060         strcpy(ifr->ifr_name, tun->dev->name);
1061
1062         ifr->ifr_flags = tun_flags(tun);
1063
1064         return 0;
1065 }
1066
1067 /* This is like a cut-down ethtool ops, except done via tun fd so no
1068  * privs required. */
1069 static int set_offload(struct net_device *dev, unsigned long arg)
1070 {
1071         unsigned int old_features, features;
1072
1073         old_features = dev->features;
1074         /* Unset features, set them as we chew on the arg. */
1075         features = (old_features & ~(NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST
1076                                     |NETIF_F_TSO_ECN|NETIF_F_TSO|NETIF_F_TSO6
1077                                     |NETIF_F_UFO));
1078
1079         if (arg & TUN_F_CSUM) {
1080                 features |= NETIF_F_HW_CSUM|NETIF_F_SG|NETIF_F_FRAGLIST;
1081                 arg &= ~TUN_F_CSUM;
1082
1083                 if (arg & (TUN_F_TSO4|TUN_F_TSO6)) {
1084                         if (arg & TUN_F_TSO_ECN) {
1085                                 features |= NETIF_F_TSO_ECN;
1086                                 arg &= ~TUN_F_TSO_ECN;
1087                         }
1088                         if (arg & TUN_F_TSO4)
1089                                 features |= NETIF_F_TSO;
1090                         if (arg & TUN_F_TSO6)
1091                                 features |= NETIF_F_TSO6;
1092                         arg &= ~(TUN_F_TSO4|TUN_F_TSO6);
1093                 }
1094
1095                 if (arg & TUN_F_UFO) {
1096                         features |= NETIF_F_UFO;
1097                         arg &= ~TUN_F_UFO;
1098                 }
1099         }
1100
1101         /* This gives the user a way to test for new features in future by
1102          * trying to set them. */
1103         if (arg)
1104                 return -EINVAL;
1105
1106         dev->features = features;
1107         if (old_features != dev->features)
1108                 netdev_features_change(dev);
1109
1110         return 0;
1111 }
1112
1113 static long tun_chr_ioctl(struct file *file, unsigned int cmd,
1114                           unsigned long arg)
1115 {
1116         struct tun_file *tfile = file->private_data;
1117         struct tun_struct *tun;
1118         void __user* argp = (void __user*)arg;
1119         struct ifreq ifr;
1120         int sndbuf;
1121         int ret;
1122
1123         if (cmd == TUNSETIFF || _IOC_TYPE(cmd) == 0x89)
1124                 if (copy_from_user(&ifr, argp, sizeof ifr))
1125                         return -EFAULT;
1126
1127         if (cmd == TUNGETFEATURES) {
1128                 /* Currently this just means: "what IFF flags are valid?".
1129                  * This is needed because we never checked for invalid flags on
1130                  * TUNSETIFF. */
1131                 return put_user(IFF_TUN | IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE |
1132                                 IFF_VNET_HDR,
1133                                 (unsigned int __user*)argp);
1134         }
1135
1136         rtnl_lock();
1137
1138         tun = __tun_get(tfile);
1139         if (cmd == TUNSETIFF && !tun) {
1140                 ifr.ifr_name[IFNAMSIZ-1] = '\0';
1141
1142                 ret = tun_set_iff(tfile->net, file, &ifr);
1143
1144                 if (ret)
1145                         goto unlock;
1146
1147                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1148                         ret = -EFAULT;
1149                 goto unlock;
1150         }
1151
1152         ret = -EBADFD;
1153         if (!tun)
1154                 goto unlock;
1155
1156         DBG(KERN_INFO "%s: tun_chr_ioctl cmd %d\n", tun->dev->name, cmd);
1157
1158         ret = 0;
1159         switch (cmd) {
1160         case TUNGETIFF:
1161                 ret = tun_get_iff(current->nsproxy->net_ns, tun, &ifr);
1162                 if (ret)
1163                         break;
1164
1165                 if (copy_to_user(argp, &ifr, sizeof(ifr)))
1166                         ret = -EFAULT;
1167                 break;
1168
1169         case TUNSETNOCSUM:
1170                 /* Disable/Enable checksum */
1171                 if (arg)
1172                         tun->flags |= TUN_NOCHECKSUM;
1173                 else
1174                         tun->flags &= ~TUN_NOCHECKSUM;
1175
1176                 DBG(KERN_INFO "%s: checksum %s\n",
1177                     tun->dev->name, arg ? "disabled" : "enabled");
1178                 break;
1179
1180         case TUNSETPERSIST:
1181                 /* Disable/Enable persist mode */
1182                 if (arg)
1183                         tun->flags |= TUN_PERSIST;
1184                 else
1185                         tun->flags &= ~TUN_PERSIST;
1186
1187                 DBG(KERN_INFO "%s: persist %s\n",
1188                     tun->dev->name, arg ? "enabled" : "disabled");
1189                 break;
1190
1191         case TUNSETOWNER:
1192                 /* Set owner of the device */
1193                 tun->owner = (uid_t) arg;
1194
1195                 DBG(KERN_INFO "%s: owner set to %d\n", tun->dev->name, tun->owner);
1196                 break;
1197
1198         case TUNSETGROUP:
1199                 /* Set group of the device */
1200                 tun->group= (gid_t) arg;
1201
1202                 DBG(KERN_INFO "%s: group set to %d\n", tun->dev->name, tun->group);
1203                 break;
1204
1205         case TUNSETLINK:
1206                 /* Only allow setting the type when the interface is down */
1207                 if (tun->dev->flags & IFF_UP) {
1208                         DBG(KERN_INFO "%s: Linktype set failed because interface is up\n",
1209                                 tun->dev->name);
1210                         ret = -EBUSY;
1211                 } else {
1212                         tun->dev->type = (int) arg;
1213                         DBG(KERN_INFO "%s: linktype set to %d\n", tun->dev->name, tun->dev->type);
1214                         ret = 0;
1215                 }
1216                 break;
1217
1218 #ifdef TUN_DEBUG
1219         case TUNSETDEBUG:
1220                 tun->debug = arg;
1221                 break;
1222 #endif
1223         case TUNSETOFFLOAD:
1224                 ret = set_offload(tun->dev, arg);
1225                 break;
1226
1227         case TUNSETTXFILTER:
1228                 /* Can be set only for TAPs */
1229                 ret = -EINVAL;
1230                 if ((tun->flags & TUN_TYPE_MASK) != TUN_TAP_DEV)
1231                         break;
1232                 ret = update_filter(&tun->txflt, (void __user *)arg);
1233                 break;
1234
1235         case SIOCGIFHWADDR:
1236                 /* Get hw addres */
1237                 memcpy(ifr.ifr_hwaddr.sa_data, tun->dev->dev_addr, ETH_ALEN);
1238                 ifr.ifr_hwaddr.sa_family = tun->dev->type;
1239                 if (copy_to_user(argp, &ifr, sizeof ifr))
1240                         ret = -EFAULT;
1241                 break;
1242
1243         case SIOCSIFHWADDR:
1244                 /* Set hw address */
1245                 DBG(KERN_DEBUG "%s: set hw address: %pM\n",
1246                         tun->dev->name, ifr.ifr_hwaddr.sa_data);
1247
1248                 ret = dev_set_mac_address(tun->dev, &ifr.ifr_hwaddr);
1249                 break;
1250
1251         case TUNGETSNDBUF:
1252                 sndbuf = tun->sk->sk_sndbuf;
1253                 if (copy_to_user(argp, &sndbuf, sizeof(sndbuf)))
1254                         ret = -EFAULT;
1255                 break;
1256
1257         case TUNSETSNDBUF:
1258                 if (copy_from_user(&sndbuf, argp, sizeof(sndbuf))) {
1259                         ret = -EFAULT;
1260                         break;
1261                 }
1262
1263                 tun->sk->sk_sndbuf = sndbuf;
1264                 break;
1265
1266         default:
1267                 ret = -EINVAL;
1268                 break;
1269         };
1270
1271 unlock:
1272         rtnl_unlock();
1273         if (tun)
1274                 tun_put(tun);
1275         return ret;
1276 }
1277
1278 static int tun_chr_fasync(int fd, struct file *file, int on)
1279 {
1280         struct tun_struct *tun = tun_get(file);
1281         int ret;
1282
1283         if (!tun)
1284                 return -EBADFD;
1285
1286         DBG(KERN_INFO "%s: tun_chr_fasync %d\n", tun->dev->name, on);
1287
1288         lock_kernel();
1289         if ((ret = fasync_helper(fd, file, on, &tun->fasync)) < 0)
1290                 goto out;
1291
1292         if (on) {
1293                 ret = __f_setown(file, task_pid(current), PIDTYPE_PID, 0);
1294                 if (ret)
1295                         goto out;
1296                 tun->flags |= TUN_FASYNC;
1297         } else
1298                 tun->flags &= ~TUN_FASYNC;
1299         ret = 0;
1300 out:
1301         unlock_kernel();
1302         tun_put(tun);
1303         return ret;
1304 }
1305
1306 static int tun_chr_open(struct inode *inode, struct file * file)
1307 {
1308         struct tun_file *tfile;
1309         cycle_kernel_lock();
1310         DBG1(KERN_INFO "tunX: tun_chr_open\n");
1311
1312         tfile = kmalloc(sizeof(*tfile), GFP_KERNEL);
1313         if (!tfile)
1314                 return -ENOMEM;
1315         atomic_set(&tfile->count, 0);
1316         tfile->tun = NULL;
1317         tfile->net = get_net(current->nsproxy->net_ns);
1318         file->private_data = tfile;
1319         return 0;
1320 }
1321
1322 static int tun_chr_close(struct inode *inode, struct file *file)
1323 {
1324         struct tun_file *tfile = file->private_data;
1325         struct tun_struct *tun;
1326
1327         tun = __tun_get(tfile);
1328         if (tun) {
1329                 struct net_device *dev = tun->dev;
1330
1331                 DBG(KERN_INFO "%s: tun_chr_close\n", dev->name);
1332
1333                 __tun_detach(tun);
1334
1335                 /* If desireable, unregister the netdevice. */
1336                 if (!(tun->flags & TUN_PERSIST)) {
1337                         rtnl_lock();
1338                         if (dev->reg_state == NETREG_REGISTERED)
1339                                 unregister_netdevice(dev);
1340                         rtnl_unlock();
1341                 }
1342         }
1343
1344         tun = tfile->tun;
1345         if (tun)
1346                 sock_put(tun->sk);
1347
1348         put_net(tfile->net);
1349         kfree(tfile);
1350
1351         return 0;
1352 }
1353
1354 static const struct file_operations tun_fops = {
1355         .owner  = THIS_MODULE,
1356         .llseek = no_llseek,
1357         .read  = do_sync_read,
1358         .aio_read  = tun_chr_aio_read,
1359         .write = do_sync_write,
1360         .aio_write = tun_chr_aio_write,
1361         .poll   = tun_chr_poll,
1362         .unlocked_ioctl = tun_chr_ioctl,
1363         .open   = tun_chr_open,
1364         .release = tun_chr_close,
1365         .fasync = tun_chr_fasync
1366 };
1367
1368 static struct miscdevice tun_miscdev = {
1369         .minor = TUN_MINOR,
1370         .name = "tun",
1371         .devnode = "net/tun",
1372         .fops = &tun_fops,
1373 };
1374
1375 /* ethtool interface */
1376
1377 static int tun_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
1378 {
1379         cmd->supported          = 0;
1380         cmd->advertising        = 0;
1381         cmd->speed              = SPEED_10;
1382         cmd->duplex             = DUPLEX_FULL;
1383         cmd->port               = PORT_TP;
1384         cmd->phy_address        = 0;
1385         cmd->transceiver        = XCVR_INTERNAL;
1386         cmd->autoneg            = AUTONEG_DISABLE;
1387         cmd->maxtxpkt           = 0;
1388         cmd->maxrxpkt           = 0;
1389         return 0;
1390 }
1391
1392 static void tun_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
1393 {
1394         struct tun_struct *tun = netdev_priv(dev);
1395
1396         strcpy(info->driver, DRV_NAME);
1397         strcpy(info->version, DRV_VERSION);
1398         strcpy(info->fw_version, "N/A");
1399
1400         switch (tun->flags & TUN_TYPE_MASK) {
1401         case TUN_TUN_DEV:
1402                 strcpy(info->bus_info, "tun");
1403                 break;
1404         case TUN_TAP_DEV:
1405                 strcpy(info->bus_info, "tap");
1406                 break;
1407         }
1408 }
1409
1410 static u32 tun_get_msglevel(struct net_device *dev)
1411 {
1412 #ifdef TUN_DEBUG
1413         struct tun_struct *tun = netdev_priv(dev);
1414         return tun->debug;
1415 #else
1416         return -EOPNOTSUPP;
1417 #endif
1418 }
1419
1420 static void tun_set_msglevel(struct net_device *dev, u32 value)
1421 {
1422 #ifdef TUN_DEBUG
1423         struct tun_struct *tun = netdev_priv(dev);
1424         tun->debug = value;
1425 #endif
1426 }
1427
1428 static u32 tun_get_link(struct net_device *dev)
1429 {
1430         struct tun_struct *tun = netdev_priv(dev);
1431         return !!tun->tfile;
1432 }
1433
1434 static u32 tun_get_rx_csum(struct net_device *dev)
1435 {
1436         struct tun_struct *tun = netdev_priv(dev);
1437         return (tun->flags & TUN_NOCHECKSUM) == 0;
1438 }
1439
1440 static int tun_set_rx_csum(struct net_device *dev, u32 data)
1441 {
1442         struct tun_struct *tun = netdev_priv(dev);
1443         if (data)
1444                 tun->flags &= ~TUN_NOCHECKSUM;
1445         else
1446                 tun->flags |= TUN_NOCHECKSUM;
1447         return 0;
1448 }
1449
1450 static const struct ethtool_ops tun_ethtool_ops = {
1451         .get_settings   = tun_get_settings,
1452         .get_drvinfo    = tun_get_drvinfo,
1453         .get_msglevel   = tun_get_msglevel,
1454         .set_msglevel   = tun_set_msglevel,
1455         .get_link       = tun_get_link,
1456         .get_rx_csum    = tun_get_rx_csum,
1457         .set_rx_csum    = tun_set_rx_csum
1458 };
1459
1460
1461 static int __init tun_init(void)
1462 {
1463         int ret = 0;
1464
1465         printk(KERN_INFO "tun: %s, %s\n", DRV_DESCRIPTION, DRV_VERSION);
1466         printk(KERN_INFO "tun: %s\n", DRV_COPYRIGHT);
1467
1468         ret = rtnl_link_register(&tun_link_ops);
1469         if (ret) {
1470                 printk(KERN_ERR "tun: Can't register link_ops\n");
1471                 goto err_linkops;
1472         }
1473
1474         ret = misc_register(&tun_miscdev);
1475         if (ret) {
1476                 printk(KERN_ERR "tun: Can't register misc device %d\n", TUN_MINOR);
1477                 goto err_misc;
1478         }
1479         return  0;
1480 err_misc:
1481         rtnl_link_unregister(&tun_link_ops);
1482 err_linkops:
1483         return ret;
1484 }
1485
1486 static void tun_cleanup(void)
1487 {
1488         misc_deregister(&tun_miscdev);
1489         rtnl_link_unregister(&tun_link_ops);
1490 }
1491
1492 module_init(tun_init);
1493 module_exit(tun_cleanup);
1494 MODULE_DESCRIPTION(DRV_DESCRIPTION);
1495 MODULE_AUTHOR(DRV_COPYRIGHT);
1496 MODULE_LICENSE("GPL");
1497 MODULE_ALIAS_MISCDEV(TUN_MINOR);