net/ipv4/ip_vti.c

   1 /*
   2  *      Linux NET3: IP/IP protocol decoder modified to support
   3  *                  virtual tunnel interface
   4  *
   5  *      Authors:
   6  *              Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  */
  14
  15 /*
  16    This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
  17
  18    For comments look at net/ipv4/ip_gre.c --ANK
  19  */
  20
  21
  22 #include <linux/capability.h>
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/kernel.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/in.h>
  30 #include <linux/tcp.h>
  31 #include <linux/udp.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/init.h>
  34 #include <linux/netfilter_ipv4.h>
  35 #include <linux/if_ether.h>
  36 #include <linux/icmpv6.h>
  37
  38 #include <net/sock.h>
  39 #include <net/ip.h>
  40 #include <net/icmp.h>
  41 #include <net/ip_tunnels.h>
  42 #include <net/inet_ecn.h>
  43 #include <net/xfrm.h>
  44 #include <net/net_namespace.h>
  45 #include <net/netns/generic.h>
  46
  47 static struct rtnl_link_ops vti_link_ops __read_mostly;
  48
  49 static int vti_net_id __read_mostly;
  50 static int vti_tunnel_init(struct net_device *dev);
  51
  52 static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
  53                      int encap_type)
  54 {
  55         struct ip_tunnel *tunnel;
  56         const struct iphdr *iph = ip_hdr(skb);
  57         struct net *net = dev_net(skb->dev);
  58         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
  59
  60         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
  61                                   iph->saddr, iph->daddr, 0);
  62         if (tunnel) {
  63                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
  64                         goto drop;
  65
  66                 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
  67
  68                 return xfrm_input(skb, nexthdr, spi, encap_type);
  69         }
  70
  71         return -EINVAL;
  72 drop:
  73         kfree_skb(skb);
  74         return 0;
  75 }
  76
  77 static int vti_rcv(struct sk_buff *skb)
  78 {
  79         XFRM_SPI_SKB_CB(skb)->family = AF_INET;
  80         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
  81
  82         return vti_input(skb, ip_hdr(skb)->protocol, 0, 0);
  83 }
  84
  85 static int vti_rcv_cb(struct sk_buff *skb, int err)
  86 {
  87         unsigned short family;
  88         struct net_device *dev;
  89         struct pcpu_sw_netstats *tstats;
  90         struct xfrm_state *x;
  91         struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
  92         u32 orig_mark = skb->mark;
  93         int ret;
  94
  95         if (!tunnel)
  96                 return 1;
  97
  98         dev = tunnel->dev;
  99
 100         if (err) {
 101                 dev->stats.rx_errors++;
 102                 dev->stats.rx_dropped++;
 103
 104                 return 0;
 105         }
 106
 107         x = xfrm_input_state(skb);
 108         family = x->inner_mode->afinfo->family;
 109
 110         skb->mark = be32_to_cpu(tunnel->parms.i_key);
 111         ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
 112         skb->mark = orig_mark;
 113
 114         if (!ret)
 115                 return -EPERM;
 116
 117         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
 118         skb->dev = dev;
 119
 120         tstats = this_cpu_ptr(dev->tstats);
 121
 122         u64_stats_update_begin(&tstats->syncp);
 123         tstats->rx_packets++;
 124         tstats->rx_bytes += skb->len;
 125         u64_stats_update_end(&tstats->syncp);
 126
 127         return 0;
 128 }
 129
 130 static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
 131 {
 132         xfrm_address_t *daddr = (xfrm_address_t *)&dst;
 133         xfrm_address_t *saddr = (xfrm_address_t *)&src;
 134
 135         /* if there is no transform then this tunnel is not functional.
 136          * Or if the xfrm is not mode tunnel.
 137          */
 138         if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
 139             x->props.family != AF_INET)
 140                 return false;
 141
 142         if (!dst)
 143                 return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
 144
 145         if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
 146                 return false;
 147
 148         return true;
 149 }
 150
 151 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
 152                             struct flowi *fl)
 153 {
 154         struct ip_tunnel *tunnel = netdev_priv(dev);
 155         struct ip_tunnel_parm *parms = &tunnel->parms;
 156         struct dst_entry *dst = skb_dst(skb);
 157         struct net_device *tdev;        /* Device to other host */
 158         int err;
 159         int mtu;
 160
 161         if (!dst) {
 162                 dev->stats.tx_carrier_errors++;
 163                 goto tx_error_icmp;
 164         }
 165
 166         dst_hold(dst);
 167         dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
 168         if (IS_ERR(dst)) {
 169                 dev->stats.tx_carrier_errors++;
 170                 goto tx_error_icmp;
 171         }
 172
 173         if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
 174                 dev->stats.tx_carrier_errors++;
 175                 dst_release(dst);
 176                 goto tx_error_icmp;
 177         }
 178
 179         tdev = dst->dev;
 180
 181         if (tdev == dev) {
 182                 dst_release(dst);
 183                 dev->stats.collisions++;
 184                 goto tx_error;
 185         }
 186
 187         if (tunnel->err_count > 0) {
 188                 if (time_before(jiffies,
 189                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 190                         tunnel->err_count--;
 191                         dst_link_failure(skb);
 192                 } else
 193                         tunnel->err_count = 0;
 194         }
 195
 196         mtu = dst_mtu(dst);
 197         if (skb->len > mtu) {
 198                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 199                 if (skb->protocol == htons(ETH_P_IP)) {
 200                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 201                                   htonl(mtu));
 202                 } else {
 203                         if (mtu < IPV6_MIN_MTU)
 204                                 mtu = IPV6_MIN_MTU;
 205
 206                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 207                 }
 208
 209                 dst_release(dst);
 210                 goto tx_error;
 211         }
 212
 213         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
 214         skb_dst_set(skb, dst);
 215         skb->dev = skb_dst(skb)->dev;
 216
 217         err = dst_output(tunnel->net, skb->sk, skb);
 218         if (net_xmit_eval(err) == 0)
 219                 err = skb->len;
 220         iptunnel_xmit_stats(dev, err);
 221         return NETDEV_TX_OK;
 222
 223 tx_error_icmp:
 224         dst_link_failure(skb);
 225 tx_error:
 226         dev->stats.tx_errors++;
 227         kfree_skb(skb);
 228         return NETDEV_TX_OK;
 229 }
 230
 231 /* This function assumes it is being called from dev_queue_xmit()
 232  * and that skb is filled properly by that function.
 233  */
 234 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 235 {
 236         struct ip_tunnel *tunnel = netdev_priv(dev);
 237         struct flowi fl;
 238
 239         memset(&fl, 0, sizeof(fl));
 240
 241         switch (skb->protocol) {
 242         case htons(ETH_P_IP):
 243                 xfrm_decode_session(skb, &fl, AF_INET);
 244                 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 245                 break;
 246         case htons(ETH_P_IPV6):
 247                 xfrm_decode_session(skb, &fl, AF_INET6);
 248                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 249                 break;
 250         default:
 251                 dev->stats.tx_errors++;
 252                 dev_kfree_skb(skb);
 253                 return NETDEV_TX_OK;
 254         }
 255
 256         /* override mark with tunnel output key */
 257         fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
 258
 259         return vti_xmit(skb, dev, &fl);
 260 }
 261
 262 static int vti4_err(struct sk_buff *skb, u32 info)
 263 {
 264         __be32 spi;
 265         __u32 mark;
 266         struct xfrm_state *x;
 267         struct ip_tunnel *tunnel;
 268         struct ip_esp_hdr *esph;
 269         struct ip_auth_hdr *ah ;
 270         struct ip_comp_hdr *ipch;
 271         struct net *net = dev_net(skb->dev);
 272         const struct iphdr *iph = (const struct iphdr *)skb->data;
 273         int protocol = iph->protocol;
 274         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 275
 276         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
 277                                   iph->daddr, iph->saddr, 0);
 278         if (!tunnel)
 279                 return -1;
 280
 281         mark = be32_to_cpu(tunnel->parms.o_key);
 282
 283         switch (protocol) {
 284         case IPPROTO_ESP:
 285                 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 286                 spi = esph->spi;
 287                 break;
 288         case IPPROTO_AH:
 289                 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
 290                 spi = ah->spi;
 291                 break;
 292         case IPPROTO_COMP:
 293                 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
 294                 spi = htonl(ntohs(ipch->cpi));
 295                 break;
 296         default:
 297                 return 0;
 298         }
 299
 300         switch (icmp_hdr(skb)->type) {
 301         case ICMP_DEST_UNREACH:
 302                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 303                         return 0;
 304         case ICMP_REDIRECT:
 305                 break;
 306         default:
 307                 return 0;
 308         }
 309
 310         x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
 311                               spi, protocol, AF_INET);
 312         if (!x)
 313                 return 0;
 314
 315         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 316                 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
 317         else
 318                 ipv4_redirect(skb, net, 0, 0, protocol, 0);
 319         xfrm_state_put(x);
 320
 321         return 0;
 322 }
 323
 324 static int
 325 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 326 {
 327         int err = 0;
 328         struct ip_tunnel_parm p;
 329
 330         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 331                 return -EFAULT;
 332
 333         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 334                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 335                     p.iph.ihl != 5)
 336                         return -EINVAL;
 337         }
 338
 339         if (!(p.i_flags & GRE_KEY))
 340                 p.i_key = 0;
 341         if (!(p.o_flags & GRE_KEY))
 342                 p.o_key = 0;
 343
 344         p.i_flags = VTI_ISVTI;
 345
 346         err = ip_tunnel_ioctl(dev, &p, cmd);
 347         if (err)
 348                 return err;
 349
 350         if (cmd != SIOCDELTUNNEL) {
 351                 p.i_flags |= GRE_KEY;
 352                 p.o_flags |= GRE_KEY;
 353         }
 354
 355         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 356                 return -EFAULT;
 357         return 0;
 358 }
 359
 360 static const struct net_device_ops vti_netdev_ops = {
 361         .ndo_init       = vti_tunnel_init,
 362         .ndo_uninit     = ip_tunnel_uninit,
 363         .ndo_start_xmit = vti_tunnel_xmit,
 364         .ndo_do_ioctl   = vti_tunnel_ioctl,
 365         .ndo_change_mtu = ip_tunnel_change_mtu,
 366         .ndo_get_stats64 = ip_tunnel_get_stats64,
 367         .ndo_get_iflink = ip_tunnel_get_iflink,
 368 };
 369
 370 static void vti_tunnel_setup(struct net_device *dev)
 371 {
 372         dev->netdev_ops         = &vti_netdev_ops;
 373         dev->type               = ARPHRD_TUNNEL;
 374         ip_tunnel_setup(dev, vti_net_id);
 375 }
 376
 377 static int vti_tunnel_init(struct net_device *dev)
 378 {
 379         struct ip_tunnel *tunnel = netdev_priv(dev);
 380         struct iphdr *iph = &tunnel->parms.iph;
 381
 382         memcpy(dev->dev_addr, &iph->saddr, 4);
 383         memcpy(dev->broadcast, &iph->daddr, 4);
 384
 385         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 386         dev->mtu                = ETH_DATA_LEN;
 387         dev->flags              = IFF_NOARP;
 388         dev->addr_len           = 4;
 389         dev->features           |= NETIF_F_LLTX;
 390         netif_keep_dst(dev);
 391
 392         return ip_tunnel_init(dev);
 393 }
 394
 395 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
 396 {
 397         struct ip_tunnel *tunnel = netdev_priv(dev);
 398         struct iphdr *iph = &tunnel->parms.iph;
 399
 400         iph->version            = 4;
 401         iph->protocol           = IPPROTO_IPIP;
 402         iph->ihl                = 5;
 403 }
 404
 405 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
 406         .handler        =       vti_rcv,
 407         .input_handler  =       vti_input,
 408         .cb_handler     =       vti_rcv_cb,
 409         .err_handler    =       vti4_err,
 410         .priority       =       100,
 411 };
 412
 413 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
 414         .handler        =       vti_rcv,
 415         .input_handler  =       vti_input,
 416         .cb_handler     =       vti_rcv_cb,
 417         .err_handler    =       vti4_err,
 418         .priority       =       100,
 419 };
 420
 421 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
 422         .handler        =       vti_rcv,
 423         .input_handler  =       vti_input,
 424         .cb_handler     =       vti_rcv_cb,
 425         .err_handler    =       vti4_err,
 426         .priority       =       100,
 427 };
 428
 429 static int __net_init vti_init_net(struct net *net)
 430 {
 431         int err;
 432         struct ip_tunnel_net *itn;
 433
 434         err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
 435         if (err)
 436                 return err;
 437         itn = net_generic(net, vti_net_id);
 438         vti_fb_tunnel_init(itn->fb_tunnel_dev);
 439         return 0;
 440 }
 441
 442 static void __net_exit vti_exit_net(struct net *net)
 443 {
 444         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 445         ip_tunnel_delete_net(itn, &vti_link_ops);
 446 }
 447
 448 static struct pernet_operations vti_net_ops = {
 449         .init = vti_init_net,
 450         .exit = vti_exit_net,
 451         .id   = &vti_net_id,
 452         .size = sizeof(struct ip_tunnel_net),
 453 };
 454
 455 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
 456 {
 457         return 0;
 458 }
 459
 460 static void vti_netlink_parms(struct nlattr *data[],
 461                               struct ip_tunnel_parm *parms)
 462 {
 463         memset(parms, 0, sizeof(*parms));
 464
 465         parms->iph.protocol = IPPROTO_IPIP;
 466
 467         if (!data)
 468                 return;
 469
 470         parms->i_flags = VTI_ISVTI;
 471
 472         if (data[IFLA_VTI_LINK])
 473                 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
 474
 475         if (data[IFLA_VTI_IKEY])
 476                 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
 477
 478         if (data[IFLA_VTI_OKEY])
 479                 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
 480
 481         if (data[IFLA_VTI_LOCAL])
 482                 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
 483
 484         if (data[IFLA_VTI_REMOTE])
 485                 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
 486
 487 }
 488
 489 static int vti_newlink(struct net *src_net, struct net_device *dev,
 490                        struct nlattr *tb[], struct nlattr *data[])
 491 {
 492         struct ip_tunnel_parm parms;
 493
 494         vti_netlink_parms(data, &parms);
 495         return ip_tunnel_newlink(dev, tb, &parms);
 496 }
 497
 498 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
 499                           struct nlattr *data[])
 500 {
 501         struct ip_tunnel_parm p;
 502
 503         vti_netlink_parms(data, &p);
 504         return ip_tunnel_changelink(dev, tb, &p);
 505 }
 506
 507 static size_t vti_get_size(const struct net_device *dev)
 508 {
 509         return
 510                 /* IFLA_VTI_LINK */
 511                 nla_total_size(4) +
 512                 /* IFLA_VTI_IKEY */
 513                 nla_total_size(4) +
 514                 /* IFLA_VTI_OKEY */
 515                 nla_total_size(4) +
 516                 /* IFLA_VTI_LOCAL */
 517                 nla_total_size(4) +
 518                 /* IFLA_VTI_REMOTE */
 519                 nla_total_size(4) +
 520                 0;
 521 }
 522
 523 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
 524 {
 525         struct ip_tunnel *t = netdev_priv(dev);
 526         struct ip_tunnel_parm *p = &t->parms;
 527
 528         nla_put_u32(skb, IFLA_VTI_LINK, p->link);
 529         nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
 530         nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
 531         nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr);
 532         nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr);
 533
 534         return 0;
 535 }
 536
 537 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
 538         [IFLA_VTI_LINK]         = { .type = NLA_U32 },
 539         [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
 540         [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
 541         [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
 542         [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
 543 };
 544
 545 static struct rtnl_link_ops vti_link_ops __read_mostly = {
 546         .kind           = "vti",
 547         .maxtype        = IFLA_VTI_MAX,
 548         .policy         = vti_policy,
 549         .priv_size      = sizeof(struct ip_tunnel),
 550         .setup          = vti_tunnel_setup,
 551         .validate       = vti_tunnel_validate,
 552         .newlink        = vti_newlink,
 553         .changelink     = vti_changelink,
 554         .dellink        = ip_tunnel_dellink,
 555         .get_size       = vti_get_size,
 556         .fill_info      = vti_fill_info,
 557         .get_link_net   = ip_tunnel_get_link_net,
 558 };
 559
 560 static bool is_vti_tunnel(const struct net_device *dev)
 561 {
 562         return dev->netdev_ops == &vti_netdev_ops;
 563 }
 564
 565 static int vti_device_event(struct notifier_block *unused,
 566                             unsigned long event, void *ptr)
 567 {
 568         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 569         struct ip_tunnel *tunnel = netdev_priv(dev);
 570
 571         if (!is_vti_tunnel(dev))
 572                 return NOTIFY_DONE;
 573
 574         switch (event) {
 575         case NETDEV_DOWN:
 576                 if (!net_eq(tunnel->net, dev_net(dev)))
 577                         xfrm_garbage_collect(tunnel->net);
 578                 break;
 579         }
 580         return NOTIFY_DONE;
 581 }
 582
 583 static struct notifier_block vti_notifier_block __read_mostly = {
 584         .notifier_call = vti_device_event,
 585 };
 586
 587 static int __init vti_init(void)
 588 {
 589         const char *msg;
 590         int err;
 591
 592         pr_info("IPv4 over IPsec tunneling driver\n");
 593
 594         register_netdevice_notifier(&vti_notifier_block);
 595
 596         msg = "tunnel device";
 597         err = register_pernet_device(&vti_net_ops);
 598         if (err < 0)
 599                 goto pernet_dev_failed;
 600
 601         msg = "tunnel protocols";
 602         err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
 603         if (err < 0)
 604                 goto xfrm_proto_esp_failed;
 605         err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
 606         if (err < 0)
 607                 goto xfrm_proto_ah_failed;
 608         err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
 609         if (err < 0)
 610                 goto xfrm_proto_comp_failed;
 611
 612         msg = "netlink interface";
 613         err = rtnl_link_register(&vti_link_ops);
 614         if (err < 0)
 615                 goto rtnl_link_failed;
 616
 617         return err;
 618
 619 rtnl_link_failed:
 620         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 621 xfrm_proto_comp_failed:
 622         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 623 xfrm_proto_ah_failed:
 624         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 625 xfrm_proto_esp_failed:
 626         unregister_pernet_device(&vti_net_ops);
 627 pernet_dev_failed:
 628         unregister_netdevice_notifier(&vti_notifier_block);
 629         pr_err("vti init: failed to register %s\n", msg);
 630         return err;
 631 }
 632
 633 static void __exit vti_fini(void)
 634 {
 635         rtnl_link_unregister(&vti_link_ops);
 636         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 637         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 638         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 639         unregister_pernet_device(&vti_net_ops);
 640         unregister_netdevice_notifier(&vti_notifier_block);
 641 }
 642
 643 module_init(vti_init);
 644 module_exit(vti_fini);
 645 MODULE_LICENSE("GPL");
 646 MODULE_ALIAS_RTNL_LINK("vti");
 647 MODULE_ALIAS_NETDEV("ip_vti0");