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 unsigned 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 xfrm_mode *inner_mode;
  92         struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
  93         u32 orig_mark = skb->mark;
  94         int ret;
  95
  96         if (!tunnel)
  97                 return 1;
  98
  99         dev = tunnel->dev;
 100
 101         if (err) {
 102                 dev->stats.rx_errors++;
 103                 dev->stats.rx_dropped++;
 104
 105                 return 0;
 106         }
 107
 108         x = xfrm_input_state(skb);
 109
 110         inner_mode = x->inner_mode;
 111
 112         if (x->sel.family == AF_UNSPEC) {
 113                 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol);
 114                 if (inner_mode == NULL) {
 115                         XFRM_INC_STATS(dev_net(skb->dev),
 116                                        LINUX_MIB_XFRMINSTATEMODEERROR);
 117                         return -EINVAL;
 118                 }
 119         }
 120
 121         family = inner_mode->afinfo->family;
 122
 123         skb->mark = be32_to_cpu(tunnel->parms.i_key);
 124         ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family);
 125         skb->mark = orig_mark;
 126
 127         if (!ret)
 128                 return -EPERM;
 129
 130         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
 131         skb->dev = dev;
 132
 133         tstats = this_cpu_ptr(dev->tstats);
 134
 135         u64_stats_update_begin(&tstats->syncp);
 136         tstats->rx_packets++;
 137         tstats->rx_bytes += skb->len;
 138         u64_stats_update_end(&tstats->syncp);
 139
 140         return 0;
 141 }
 142
 143 static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
 144 {
 145         xfrm_address_t *daddr = (xfrm_address_t *)&dst;
 146         xfrm_address_t *saddr = (xfrm_address_t *)&src;
 147
 148         /* if there is no transform then this tunnel is not functional.
 149          * Or if the xfrm is not mode tunnel.
 150          */
 151         if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
 152             x->props.family != AF_INET)
 153                 return false;
 154
 155         if (!dst)
 156                 return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
 157
 158         if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
 159                 return false;
 160
 161         return true;
 162 }
 163
 164 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
 165                             struct flowi *fl)
 166 {
 167         struct ip_tunnel *tunnel = netdev_priv(dev);
 168         struct ip_tunnel_parm *parms = &tunnel->parms;
 169         struct dst_entry *dst = skb_dst(skb);
 170         struct net_device *tdev;        /* Device to other host */
 171         int pkt_len = skb->len;
 172         int err;
 173         int mtu;
 174
 175         if (!dst) {
 176                 dev->stats.tx_carrier_errors++;
 177                 goto tx_error_icmp;
 178         }
 179
 180         dst_hold(dst);
 181         dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
 182         if (IS_ERR(dst)) {
 183                 dev->stats.tx_carrier_errors++;
 184                 goto tx_error_icmp;
 185         }
 186
 187         if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
 188                 dev->stats.tx_carrier_errors++;
 189                 dst_release(dst);
 190                 goto tx_error_icmp;
 191         }
 192
 193         tdev = dst->dev;
 194
 195         if (tdev == dev) {
 196                 dst_release(dst);
 197                 dev->stats.collisions++;
 198                 goto tx_error;
 199         }
 200
 201         mtu = dst_mtu(dst);
 202         if (skb->len > mtu) {
 203                 skb_dst_update_pmtu(skb, mtu);
 204                 if (skb->protocol == htons(ETH_P_IP)) {
 205                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 206                                   htonl(mtu));
 207                 } else {
 208                         if (mtu < IPV6_MIN_MTU)
 209                                 mtu = IPV6_MIN_MTU;
 210
 211                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 212                 }
 213
 214                 dst_release(dst);
 215                 goto tx_error;
 216         }
 217
 218         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
 219         skb_dst_set(skb, dst);
 220         skb->dev = skb_dst(skb)->dev;
 221
 222         err = dst_output(tunnel->net, skb->sk, skb);
 223         if (net_xmit_eval(err) == 0)
 224                 err = pkt_len;
 225         iptunnel_xmit_stats(dev, err);
 226         return NETDEV_TX_OK;
 227
 228 tx_error_icmp:
 229         dst_link_failure(skb);
 230 tx_error:
 231         dev->stats.tx_errors++;
 232         kfree_skb(skb);
 233         return NETDEV_TX_OK;
 234 }
 235
 236 /* This function assumes it is being called from dev_queue_xmit()
 237  * and that skb is filled properly by that function.
 238  */
 239 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 240 {
 241         struct ip_tunnel *tunnel = netdev_priv(dev);
 242         struct flowi fl;
 243
 244         memset(&fl, 0, sizeof(fl));
 245
 246         switch (skb->protocol) {
 247         case htons(ETH_P_IP):
 248                 xfrm_decode_session(skb, &fl, AF_INET);
 249                 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 250                 break;
 251         case htons(ETH_P_IPV6):
 252                 xfrm_decode_session(skb, &fl, AF_INET6);
 253                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 254                 break;
 255         default:
 256                 dev->stats.tx_errors++;
 257                 dev_kfree_skb(skb);
 258                 return NETDEV_TX_OK;
 259         }
 260
 261         /* override mark with tunnel output key */
 262         fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
 263
 264         return vti_xmit(skb, dev, &fl);
 265 }
 266
 267 static int vti4_err(struct sk_buff *skb, u32 info)
 268 {
 269         __be32 spi;
 270         __u32 mark;
 271         struct xfrm_state *x;
 272         struct ip_tunnel *tunnel;
 273         struct ip_esp_hdr *esph;
 274         struct ip_auth_hdr *ah ;
 275         struct ip_comp_hdr *ipch;
 276         struct net *net = dev_net(skb->dev);
 277         const struct iphdr *iph = (const struct iphdr *)skb->data;
 278         int protocol = iph->protocol;
 279         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 280
 281         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
 282                                   iph->daddr, iph->saddr, 0);
 283         if (!tunnel)
 284                 return -1;
 285
 286         mark = be32_to_cpu(tunnel->parms.o_key);
 287
 288         switch (protocol) {
 289         case IPPROTO_ESP:
 290                 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 291                 spi = esph->spi;
 292                 break;
 293         case IPPROTO_AH:
 294                 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
 295                 spi = ah->spi;
 296                 break;
 297         case IPPROTO_COMP:
 298                 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
 299                 spi = htonl(ntohs(ipch->cpi));
 300                 break;
 301         default:
 302                 return 0;
 303         }
 304
 305         switch (icmp_hdr(skb)->type) {
 306         case ICMP_DEST_UNREACH:
 307                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 308                         return 0;
 309         case ICMP_REDIRECT:
 310                 break;
 311         default:
 312                 return 0;
 313         }
 314
 315         x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
 316                               spi, protocol, AF_INET);
 317         if (!x)
 318                 return 0;
 319
 320         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 321                 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
 322         else
 323                 ipv4_redirect(skb, net, 0, 0, protocol, 0);
 324         xfrm_state_put(x);
 325
 326         return 0;
 327 }
 328
 329 static int
 330 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 331 {
 332         int err = 0;
 333         struct ip_tunnel_parm p;
 334
 335         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 336                 return -EFAULT;
 337
 338         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 339                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 340                     p.iph.ihl != 5)
 341                         return -EINVAL;
 342         }
 343
 344         if (!(p.i_flags & GRE_KEY))
 345                 p.i_key = 0;
 346         if (!(p.o_flags & GRE_KEY))
 347                 p.o_key = 0;
 348
 349         p.i_flags = VTI_ISVTI;
 350
 351         err = ip_tunnel_ioctl(dev, &p, cmd);
 352         if (err)
 353                 return err;
 354
 355         if (cmd != SIOCDELTUNNEL) {
 356                 p.i_flags |= GRE_KEY;
 357                 p.o_flags |= GRE_KEY;
 358         }
 359
 360         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 361                 return -EFAULT;
 362         return 0;
 363 }
 364
 365 static const struct net_device_ops vti_netdev_ops = {
 366         .ndo_init       = vti_tunnel_init,
 367         .ndo_uninit     = ip_tunnel_uninit,
 368         .ndo_start_xmit = vti_tunnel_xmit,
 369         .ndo_do_ioctl   = vti_tunnel_ioctl,
 370         .ndo_change_mtu = ip_tunnel_change_mtu,
 371         .ndo_get_stats64 = ip_tunnel_get_stats64,
 372         .ndo_get_iflink = ip_tunnel_get_iflink,
 373 };
 374
 375 static void vti_tunnel_setup(struct net_device *dev)
 376 {
 377         dev->netdev_ops         = &vti_netdev_ops;
 378         dev->type               = ARPHRD_TUNNEL;
 379         ip_tunnel_setup(dev, vti_net_id);
 380 }
 381
 382 static int vti_tunnel_init(struct net_device *dev)
 383 {
 384         struct ip_tunnel *tunnel = netdev_priv(dev);
 385         struct iphdr *iph = &tunnel->parms.iph;
 386
 387         memcpy(dev->dev_addr, &iph->saddr, 4);
 388         memcpy(dev->broadcast, &iph->daddr, 4);
 389
 390         dev->flags              = IFF_NOARP;
 391         dev->addr_len           = 4;
 392         dev->features           |= NETIF_F_LLTX;
 393         netif_keep_dst(dev);
 394
 395         return ip_tunnel_init(dev);
 396 }
 397
 398 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
 399 {
 400         struct ip_tunnel *tunnel = netdev_priv(dev);
 401         struct iphdr *iph = &tunnel->parms.iph;
 402
 403         iph->version            = 4;
 404         iph->protocol           = IPPROTO_IPIP;
 405         iph->ihl                = 5;
 406 }
 407
 408 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
 409         .handler        =       vti_rcv,
 410         .input_handler  =       vti_input,
 411         .cb_handler     =       vti_rcv_cb,
 412         .err_handler    =       vti4_err,
 413         .priority       =       100,
 414 };
 415
 416 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
 417         .handler        =       vti_rcv,
 418         .input_handler  =       vti_input,
 419         .cb_handler     =       vti_rcv_cb,
 420         .err_handler    =       vti4_err,
 421         .priority       =       100,
 422 };
 423
 424 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
 425         .handler        =       vti_rcv,
 426         .input_handler  =       vti_input,
 427         .cb_handler     =       vti_rcv_cb,
 428         .err_handler    =       vti4_err,
 429         .priority       =       100,
 430 };
 431
 432 static int __net_init vti_init_net(struct net *net)
 433 {
 434         int err;
 435         struct ip_tunnel_net *itn;
 436
 437         err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
 438         if (err)
 439                 return err;
 440         itn = net_generic(net, vti_net_id);
 441         if (itn->fb_tunnel_dev)
 442                 vti_fb_tunnel_init(itn->fb_tunnel_dev);
 443         return 0;
 444 }
 445
 446 static void __net_exit vti_exit_batch_net(struct list_head *list_net)
 447 {
 448         ip_tunnel_delete_nets(list_net, vti_net_id, &vti_link_ops);
 449 }
 450
 451 static struct pernet_operations vti_net_ops = {
 452         .init = vti_init_net,
 453         .exit_batch = vti_exit_batch_net,
 454         .id   = &vti_net_id,
 455         .size = sizeof(struct ip_tunnel_net),
 456 };
 457
 458 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
 459                                struct netlink_ext_ack *extack)
 460 {
 461         return 0;
 462 }
 463
 464 static void vti_netlink_parms(struct nlattr *data[],
 465                               struct ip_tunnel_parm *parms,
 466                               __u32 *fwmark)
 467 {
 468         memset(parms, 0, sizeof(*parms));
 469
 470         parms->iph.protocol = IPPROTO_IPIP;
 471
 472         if (!data)
 473                 return;
 474
 475         parms->i_flags = VTI_ISVTI;
 476
 477         if (data[IFLA_VTI_LINK])
 478                 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
 479
 480         if (data[IFLA_VTI_IKEY])
 481                 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
 482
 483         if (data[IFLA_VTI_OKEY])
 484                 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
 485
 486         if (data[IFLA_VTI_LOCAL])
 487                 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
 488
 489         if (data[IFLA_VTI_REMOTE])
 490                 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
 491
 492         if (data[IFLA_VTI_FWMARK])
 493                 *fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]);
 494 }
 495
 496 static int vti_newlink(struct net *src_net, struct net_device *dev,
 497                        struct nlattr *tb[], struct nlattr *data[],
 498                        struct netlink_ext_ack *extack)
 499 {
 500         struct ip_tunnel_parm parms;
 501         __u32 fwmark = 0;
 502
 503         vti_netlink_parms(data, &parms, &fwmark);
 504         return ip_tunnel_newlink(dev, tb, &parms, fwmark);
 505 }
 506
 507 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
 508                           struct nlattr *data[],
 509                           struct netlink_ext_ack *extack)
 510 {
 511         struct ip_tunnel *t = netdev_priv(dev);
 512         __u32 fwmark = t->fwmark;
 513         struct ip_tunnel_parm p;
 514
 515         vti_netlink_parms(data, &p, &fwmark);
 516         return ip_tunnel_changelink(dev, tb, &p, fwmark);
 517 }
 518
 519 static size_t vti_get_size(const struct net_device *dev)
 520 {
 521         return
 522                 /* IFLA_VTI_LINK */
 523                 nla_total_size(4) +
 524                 /* IFLA_VTI_IKEY */
 525                 nla_total_size(4) +
 526                 /* IFLA_VTI_OKEY */
 527                 nla_total_size(4) +
 528                 /* IFLA_VTI_LOCAL */
 529                 nla_total_size(4) +
 530                 /* IFLA_VTI_REMOTE */
 531                 nla_total_size(4) +
 532                 /* IFLA_VTI_FWMARK */
 533                 nla_total_size(4) +
 534                 0;
 535 }
 536
 537 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
 538 {
 539         struct ip_tunnel *t = netdev_priv(dev);
 540         struct ip_tunnel_parm *p = &t->parms;
 541
 542         if (nla_put_u32(skb, IFLA_VTI_LINK, p->link) ||
 543             nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key) ||
 544             nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key) ||
 545             nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr) ||
 546             nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr) ||
 547             nla_put_u32(skb, IFLA_VTI_FWMARK, t->fwmark))
 548                 return -EMSGSIZE;
 549
 550         return 0;
 551 }
 552
 553 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
 554         [IFLA_VTI_LINK]         = { .type = NLA_U32 },
 555         [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
 556         [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
 557         [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
 558         [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
 559         [IFLA_VTI_FWMARK]       = { .type = NLA_U32 },
 560 };
 561
 562 static struct rtnl_link_ops vti_link_ops __read_mostly = {
 563         .kind           = "vti",
 564         .maxtype        = IFLA_VTI_MAX,
 565         .policy         = vti_policy,
 566         .priv_size      = sizeof(struct ip_tunnel),
 567         .setup          = vti_tunnel_setup,
 568         .validate       = vti_tunnel_validate,
 569         .newlink        = vti_newlink,
 570         .changelink     = vti_changelink,
 571         .dellink        = ip_tunnel_dellink,
 572         .get_size       = vti_get_size,
 573         .fill_info      = vti_fill_info,
 574         .get_link_net   = ip_tunnel_get_link_net,
 575 };
 576
 577 static int __init vti_init(void)
 578 {
 579         const char *msg;
 580         int err;
 581
 582         pr_info("IPv4 over IPsec tunneling driver\n");
 583
 584         msg = "tunnel device";
 585         err = register_pernet_device(&vti_net_ops);
 586         if (err < 0)
 587                 goto pernet_dev_failed;
 588
 589         msg = "tunnel protocols";
 590         err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
 591         if (err < 0)
 592                 goto xfrm_proto_esp_failed;
 593         err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
 594         if (err < 0)
 595                 goto xfrm_proto_ah_failed;
 596         err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
 597         if (err < 0)
 598                 goto xfrm_proto_comp_failed;
 599
 600         msg = "netlink interface";
 601         err = rtnl_link_register(&vti_link_ops);
 602         if (err < 0)
 603                 goto rtnl_link_failed;
 604
 605         return err;
 606
 607 rtnl_link_failed:
 608         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 609 xfrm_proto_comp_failed:
 610         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 611 xfrm_proto_ah_failed:
 612         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 613 xfrm_proto_esp_failed:
 614         unregister_pernet_device(&vti_net_ops);
 615 pernet_dev_failed:
 616         pr_err("vti init: failed to register %s\n", msg);
 617         return err;
 618 }
 619
 620 static void __exit vti_fini(void)
 621 {
 622         rtnl_link_unregister(&vti_link_ops);
 623         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 624         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 625         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 626         unregister_pernet_device(&vti_net_ops);
 627 }
 628
 629 module_init(vti_init);
 630 module_exit(vti_fini);
 631 MODULE_LICENSE("GPL");
 632 MODULE_ALIAS_RTNL_LINK("vti");
 633 MODULE_ALIAS_NETDEV("ip_vti0");