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 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 err;
 172         int mtu;
 173
 174         if (!dst) {
 175                 dev->stats.tx_carrier_errors++;
 176                 goto tx_error_icmp;
 177         }
 178
 179         dst_hold(dst);
 180         dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
 181         if (IS_ERR(dst)) {
 182                 dev->stats.tx_carrier_errors++;
 183                 goto tx_error_icmp;
 184         }
 185
 186         if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
 187                 dev->stats.tx_carrier_errors++;
 188                 dst_release(dst);
 189                 goto tx_error_icmp;
 190         }
 191
 192         tdev = dst->dev;
 193
 194         if (tdev == dev) {
 195                 dst_release(dst);
 196                 dev->stats.collisions++;
 197                 goto tx_error;
 198         }
 199
 200         if (tunnel->err_count > 0) {
 201                 if (time_before(jiffies,
 202                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 203                         tunnel->err_count--;
 204                         dst_link_failure(skb);
 205                 } else
 206                         tunnel->err_count = 0;
 207         }
 208
 209         mtu = dst_mtu(dst);
 210         if (skb->len > mtu) {
 211                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 212                 if (skb->protocol == htons(ETH_P_IP)) {
 213                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 214                                   htonl(mtu));
 215                 } else {
 216                         if (mtu < IPV6_MIN_MTU)
 217                                 mtu = IPV6_MIN_MTU;
 218
 219                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 220                 }
 221
 222                 dst_release(dst);
 223                 goto tx_error;
 224         }
 225
 226         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
 227         skb_dst_set(skb, dst);
 228         skb->dev = skb_dst(skb)->dev;
 229
 230         err = dst_output(tunnel->net, skb->sk, skb);
 231         if (net_xmit_eval(err) == 0)
 232                 err = skb->len;
 233         iptunnel_xmit_stats(dev, err);
 234         return NETDEV_TX_OK;
 235
 236 tx_error_icmp:
 237         dst_link_failure(skb);
 238 tx_error:
 239         dev->stats.tx_errors++;
 240         kfree_skb(skb);
 241         return NETDEV_TX_OK;
 242 }
 243
 244 /* This function assumes it is being called from dev_queue_xmit()
 245  * and that skb is filled properly by that function.
 246  */
 247 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 248 {
 249         struct ip_tunnel *tunnel = netdev_priv(dev);
 250         struct flowi fl;
 251
 252         memset(&fl, 0, sizeof(fl));
 253
 254         switch (skb->protocol) {
 255         case htons(ETH_P_IP):
 256                 xfrm_decode_session(skb, &fl, AF_INET);
 257                 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 258                 break;
 259         case htons(ETH_P_IPV6):
 260                 xfrm_decode_session(skb, &fl, AF_INET6);
 261                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 262                 break;
 263         default:
 264                 dev->stats.tx_errors++;
 265                 dev_kfree_skb(skb);
 266                 return NETDEV_TX_OK;
 267         }
 268
 269         /* override mark with tunnel output key */
 270         fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key);
 271
 272         return vti_xmit(skb, dev, &fl);
 273 }
 274
 275 static int vti4_err(struct sk_buff *skb, u32 info)
 276 {
 277         __be32 spi;
 278         __u32 mark;
 279         struct xfrm_state *x;
 280         struct ip_tunnel *tunnel;
 281         struct ip_esp_hdr *esph;
 282         struct ip_auth_hdr *ah ;
 283         struct ip_comp_hdr *ipch;
 284         struct net *net = dev_net(skb->dev);
 285         const struct iphdr *iph = (const struct iphdr *)skb->data;
 286         int protocol = iph->protocol;
 287         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 288
 289         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
 290                                   iph->daddr, iph->saddr, 0);
 291         if (!tunnel)
 292                 return -1;
 293
 294         mark = be32_to_cpu(tunnel->parms.o_key);
 295
 296         switch (protocol) {
 297         case IPPROTO_ESP:
 298                 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 299                 spi = esph->spi;
 300                 break;
 301         case IPPROTO_AH:
 302                 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
 303                 spi = ah->spi;
 304                 break;
 305         case IPPROTO_COMP:
 306                 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
 307                 spi = htonl(ntohs(ipch->cpi));
 308                 break;
 309         default:
 310                 return 0;
 311         }
 312
 313         switch (icmp_hdr(skb)->type) {
 314         case ICMP_DEST_UNREACH:
 315                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 316                         return 0;
 317         case ICMP_REDIRECT:
 318                 break;
 319         default:
 320                 return 0;
 321         }
 322
 323         x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr,
 324                               spi, protocol, AF_INET);
 325         if (!x)
 326                 return 0;
 327
 328         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 329                 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
 330         else
 331                 ipv4_redirect(skb, net, 0, 0, protocol, 0);
 332         xfrm_state_put(x);
 333
 334         return 0;
 335 }
 336
 337 static int
 338 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 339 {
 340         int err = 0;
 341         struct ip_tunnel_parm p;
 342
 343         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 344                 return -EFAULT;
 345
 346         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 347                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 348                     p.iph.ihl != 5)
 349                         return -EINVAL;
 350         }
 351
 352         if (!(p.i_flags & GRE_KEY))
 353                 p.i_key = 0;
 354         if (!(p.o_flags & GRE_KEY))
 355                 p.o_key = 0;
 356
 357         p.i_flags = VTI_ISVTI;
 358
 359         err = ip_tunnel_ioctl(dev, &p, cmd);
 360         if (err)
 361                 return err;
 362
 363         if (cmd != SIOCDELTUNNEL) {
 364                 p.i_flags |= GRE_KEY;
 365                 p.o_flags |= GRE_KEY;
 366         }
 367
 368         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 369                 return -EFAULT;
 370         return 0;
 371 }
 372
 373 static const struct net_device_ops vti_netdev_ops = {
 374         .ndo_init       = vti_tunnel_init,
 375         .ndo_uninit     = ip_tunnel_uninit,
 376         .ndo_start_xmit = vti_tunnel_xmit,
 377         .ndo_do_ioctl   = vti_tunnel_ioctl,
 378         .ndo_change_mtu = ip_tunnel_change_mtu,
 379         .ndo_get_stats64 = ip_tunnel_get_stats64,
 380         .ndo_get_iflink = ip_tunnel_get_iflink,
 381 };
 382
 383 static void vti_tunnel_setup(struct net_device *dev)
 384 {
 385         dev->netdev_ops         = &vti_netdev_ops;
 386         dev->type               = ARPHRD_TUNNEL;
 387         ip_tunnel_setup(dev, vti_net_id);
 388 }
 389
 390 static int vti_tunnel_init(struct net_device *dev)
 391 {
 392         struct ip_tunnel *tunnel = netdev_priv(dev);
 393         struct iphdr *iph = &tunnel->parms.iph;
 394
 395         memcpy(dev->dev_addr, &iph->saddr, 4);
 396         memcpy(dev->broadcast, &iph->daddr, 4);
 397
 398         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 399         dev->mtu                = ETH_DATA_LEN;
 400         dev->flags              = IFF_NOARP;
 401         dev->addr_len           = 4;
 402         dev->features           |= NETIF_F_LLTX;
 403         netif_keep_dst(dev);
 404
 405         return ip_tunnel_init(dev);
 406 }
 407
 408 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
 409 {
 410         struct ip_tunnel *tunnel = netdev_priv(dev);
 411         struct iphdr *iph = &tunnel->parms.iph;
 412
 413         iph->version            = 4;
 414         iph->protocol           = IPPROTO_IPIP;
 415         iph->ihl                = 5;
 416 }
 417
 418 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
 419         .handler        =       vti_rcv,
 420         .input_handler  =       vti_input,
 421         .cb_handler     =       vti_rcv_cb,
 422         .err_handler    =       vti4_err,
 423         .priority       =       100,
 424 };
 425
 426 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
 427         .handler        =       vti_rcv,
 428         .input_handler  =       vti_input,
 429         .cb_handler     =       vti_rcv_cb,
 430         .err_handler    =       vti4_err,
 431         .priority       =       100,
 432 };
 433
 434 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
 435         .handler        =       vti_rcv,
 436         .input_handler  =       vti_input,
 437         .cb_handler     =       vti_rcv_cb,
 438         .err_handler    =       vti4_err,
 439         .priority       =       100,
 440 };
 441
 442 static int __net_init vti_init_net(struct net *net)
 443 {
 444         int err;
 445         struct ip_tunnel_net *itn;
 446
 447         err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
 448         if (err)
 449                 return err;
 450         itn = net_generic(net, vti_net_id);
 451         vti_fb_tunnel_init(itn->fb_tunnel_dev);
 452         return 0;
 453 }
 454
 455 static void __net_exit vti_exit_net(struct net *net)
 456 {
 457         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 458         ip_tunnel_delete_net(itn, &vti_link_ops);
 459 }
 460
 461 static struct pernet_operations vti_net_ops = {
 462         .init = vti_init_net,
 463         .exit = vti_exit_net,
 464         .id   = &vti_net_id,
 465         .size = sizeof(struct ip_tunnel_net),
 466 };
 467
 468 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
 469 {
 470         return 0;
 471 }
 472
 473 static void vti_netlink_parms(struct nlattr *data[],
 474                               struct ip_tunnel_parm *parms)
 475 {
 476         memset(parms, 0, sizeof(*parms));
 477
 478         parms->iph.protocol = IPPROTO_IPIP;
 479
 480         if (!data)
 481                 return;
 482
 483         parms->i_flags = VTI_ISVTI;
 484
 485         if (data[IFLA_VTI_LINK])
 486                 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
 487
 488         if (data[IFLA_VTI_IKEY])
 489                 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
 490
 491         if (data[IFLA_VTI_OKEY])
 492                 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
 493
 494         if (data[IFLA_VTI_LOCAL])
 495                 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]);
 496
 497         if (data[IFLA_VTI_REMOTE])
 498                 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]);
 499
 500 }
 501
 502 static int vti_newlink(struct net *src_net, struct net_device *dev,
 503                        struct nlattr *tb[], struct nlattr *data[])
 504 {
 505         struct ip_tunnel_parm parms;
 506
 507         vti_netlink_parms(data, &parms);
 508         return ip_tunnel_newlink(dev, tb, &parms);
 509 }
 510
 511 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
 512                           struct nlattr *data[])
 513 {
 514         struct ip_tunnel_parm p;
 515
 516         vti_netlink_parms(data, &p);
 517         return ip_tunnel_changelink(dev, tb, &p);
 518 }
 519
 520 static size_t vti_get_size(const struct net_device *dev)
 521 {
 522         return
 523                 /* IFLA_VTI_LINK */
 524                 nla_total_size(4) +
 525                 /* IFLA_VTI_IKEY */
 526                 nla_total_size(4) +
 527                 /* IFLA_VTI_OKEY */
 528                 nla_total_size(4) +
 529                 /* IFLA_VTI_LOCAL */
 530                 nla_total_size(4) +
 531                 /* IFLA_VTI_REMOTE */
 532                 nla_total_size(4) +
 533                 0;
 534 }
 535
 536 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
 537 {
 538         struct ip_tunnel *t = netdev_priv(dev);
 539         struct ip_tunnel_parm *p = &t->parms;
 540
 541         nla_put_u32(skb, IFLA_VTI_LINK, p->link);
 542         nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
 543         nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
 544         nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr);
 545         nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr);
 546
 547         return 0;
 548 }
 549
 550 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
 551         [IFLA_VTI_LINK]         = { .type = NLA_U32 },
 552         [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
 553         [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
 554         [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
 555         [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
 556 };
 557
 558 static struct rtnl_link_ops vti_link_ops __read_mostly = {
 559         .kind           = "vti",
 560         .maxtype        = IFLA_VTI_MAX,
 561         .policy         = vti_policy,
 562         .priv_size      = sizeof(struct ip_tunnel),
 563         .setup          = vti_tunnel_setup,
 564         .validate       = vti_tunnel_validate,
 565         .newlink        = vti_newlink,
 566         .changelink     = vti_changelink,
 567         .dellink        = ip_tunnel_dellink,
 568         .get_size       = vti_get_size,
 569         .fill_info      = vti_fill_info,
 570         .get_link_net   = ip_tunnel_get_link_net,
 571 };
 572
 573 static bool is_vti_tunnel(const struct net_device *dev)
 574 {
 575         return dev->netdev_ops == &vti_netdev_ops;
 576 }
 577
 578 static int vti_device_event(struct notifier_block *unused,
 579                             unsigned long event, void *ptr)
 580 {
 581         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 582         struct ip_tunnel *tunnel = netdev_priv(dev);
 583
 584         if (!is_vti_tunnel(dev))
 585                 return NOTIFY_DONE;
 586
 587         switch (event) {
 588         case NETDEV_DOWN:
 589                 if (!net_eq(tunnel->net, dev_net(dev)))
 590                         xfrm_garbage_collect(tunnel->net);
 591                 break;
 592         }
 593         return NOTIFY_DONE;
 594 }
 595
 596 static struct notifier_block vti_notifier_block __read_mostly = {
 597         .notifier_call = vti_device_event,
 598 };
 599
 600 static int __init vti_init(void)
 601 {
 602         const char *msg;
 603         int err;
 604
 605         pr_info("IPv4 over IPsec tunneling driver\n");
 606
 607         register_netdevice_notifier(&vti_notifier_block);
 608
 609         msg = "tunnel device";
 610         err = register_pernet_device(&vti_net_ops);
 611         if (err < 0)
 612                 goto pernet_dev_failed;
 613
 614         msg = "tunnel protocols";
 615         err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
 616         if (err < 0)
 617                 goto xfrm_proto_esp_failed;
 618         err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
 619         if (err < 0)
 620                 goto xfrm_proto_ah_failed;
 621         err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
 622         if (err < 0)
 623                 goto xfrm_proto_comp_failed;
 624
 625         msg = "netlink interface";
 626         err = rtnl_link_register(&vti_link_ops);
 627         if (err < 0)
 628                 goto rtnl_link_failed;
 629
 630         return err;
 631
 632 rtnl_link_failed:
 633         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 634 xfrm_proto_comp_failed:
 635         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 636 xfrm_proto_ah_failed:
 637         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 638 xfrm_proto_esp_failed:
 639         unregister_pernet_device(&vti_net_ops);
 640 pernet_dev_failed:
 641         unregister_netdevice_notifier(&vti_notifier_block);
 642         pr_err("vti init: failed to register %s\n", msg);
 643         return err;
 644 }
 645
 646 static void __exit vti_fini(void)
 647 {
 648         rtnl_link_unregister(&vti_link_ops);
 649         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 650         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 651         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 652         unregister_pernet_device(&vti_net_ops);
 653         unregister_netdevice_notifier(&vti_notifier_block);
 654 }
 655
 656 module_init(vti_init);
 657 module_exit(vti_fini);
 658 MODULE_LICENSE("GPL");
 659 MODULE_ALIAS_RTNL_LINK("vti");
 660 MODULE_ALIAS_NETDEV("ip_vti0");