net/ipv6/sit.c

   1 /*
   2  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Changes:
  15  * Roger Venning <r.venning@telstra.com>:       6to4 support
  16  * Nate Thompson <nate@thebog.net>:             6to4 support
  17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/capability.h>
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/net.h>
  29 #include <linux/in6.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/if_arp.h>
  32 #include <linux/icmp.h>
  33 #include <linux/slab.h>
  34 #include <asm/uaccess.h>
  35 #include <linux/init.h>
  36 #include <linux/netfilter_ipv4.h>
  37 #include <linux/if_ether.h>
  38
  39 #include <net/sock.h>
  40 #include <net/snmp.h>
  41
  42 #include <net/ipv6.h>
  43 #include <net/protocol.h>
  44 #include <net/transp_v6.h>
  45 #include <net/ip6_fib.h>
  46 #include <net/ip6_route.h>
  47 #include <net/ndisc.h>
  48 #include <net/addrconf.h>
  49 #include <net/ip.h>
  50 #include <net/udp.h>
  51 #include <net/icmp.h>
  52 #include <net/ip_tunnels.h>
  53 #include <net/inet_ecn.h>
  54 #include <net/xfrm.h>
  55 #include <net/dsfield.h>
  56 #include <net/net_namespace.h>
  57 #include <net/netns/generic.h>
  58
  59 /*
  60    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  61
  62    For comments look at net/ipv4/ip_gre.c --ANK
  63  */
  64
  65 #define HASH_SIZE  16
  66 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  67
  68 static bool log_ecn_error = true;
  69 module_param(log_ecn_error, bool, 0644);
  70 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  71
  72 static int ipip6_tunnel_init(struct net_device *dev);
  73 static void ipip6_tunnel_setup(struct net_device *dev);
  74 static void ipip6_dev_free(struct net_device *dev);
  75 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  76                       __be32 *v4dst);
  77 static struct rtnl_link_ops sit_link_ops __read_mostly;
  78
  79 static int sit_net_id __read_mostly;
  80 struct sit_net {
  81         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  82         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  83         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  84         struct ip_tunnel __rcu *tunnels_wc[1];
  85         struct ip_tunnel __rcu **tunnels[4];
  86
  87         struct net_device *fb_tunnel_dev;
  88 };
  89
  90 /*
  91  * Must be invoked with rcu_read_lock
  92  */
  93 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  94                 struct net_device *dev, __be32 remote, __be32 local)
  95 {
  96         unsigned int h0 = HASH(remote);
  97         unsigned int h1 = HASH(local);
  98         struct ip_tunnel *t;
  99         struct sit_net *sitn = net_generic(net, sit_net_id);
 100
 101         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 102                 if (local == t->parms.iph.saddr &&
 103                     remote == t->parms.iph.daddr &&
 104                     (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 105                     (t->dev->flags & IFF_UP))
 106                         return t;
 107         }
 108         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 109                 if (remote == t->parms.iph.daddr &&
 110                     (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 111                     (t->dev->flags & IFF_UP))
 112                         return t;
 113         }
 114         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 115                 if (local == t->parms.iph.saddr &&
 116                     (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 117                     (t->dev->flags & IFF_UP))
 118                         return t;
 119         }
 120         t = rcu_dereference(sitn->tunnels_wc[0]);
 121         if (t && (t->dev->flags & IFF_UP))
 122                 return t;
 123         return NULL;
 124 }
 125
 126 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 127                 struct ip_tunnel_parm *parms)
 128 {
 129         __be32 remote = parms->iph.daddr;
 130         __be32 local = parms->iph.saddr;
 131         unsigned int h = 0;
 132         int prio = 0;
 133
 134         if (remote) {
 135                 prio |= 2;
 136                 h ^= HASH(remote);
 137         }
 138         if (local) {
 139                 prio |= 1;
 140                 h ^= HASH(local);
 141         }
 142         return &sitn->tunnels[prio][h];
 143 }
 144
 145 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 146                 struct ip_tunnel *t)
 147 {
 148         return __ipip6_bucket(sitn, &t->parms);
 149 }
 150
 151 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 152 {
 153         struct ip_tunnel __rcu **tp;
 154         struct ip_tunnel *iter;
 155
 156         for (tp = ipip6_bucket(sitn, t);
 157              (iter = rtnl_dereference(*tp)) != NULL;
 158              tp = &iter->next) {
 159                 if (t == iter) {
 160                         rcu_assign_pointer(*tp, t->next);
 161                         break;
 162                 }
 163         }
 164 }
 165
 166 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 167 {
 168         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 169
 170         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 171         rcu_assign_pointer(*tp, t);
 172 }
 173
 174 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 175 {
 176 #ifdef CONFIG_IPV6_SIT_6RD
 177         struct ip_tunnel *t = netdev_priv(dev);
 178
 179         if (t->dev == sitn->fb_tunnel_dev) {
 180                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 181                 t->ip6rd.relay_prefix = 0;
 182                 t->ip6rd.prefixlen = 16;
 183                 t->ip6rd.relay_prefixlen = 0;
 184         } else {
 185                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 186                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 187         }
 188 #endif
 189 }
 190
 191 static int ipip6_tunnel_create(struct net_device *dev)
 192 {
 193         struct ip_tunnel *t = netdev_priv(dev);
 194         struct net *net = dev_net(dev);
 195         struct sit_net *sitn = net_generic(net, sit_net_id);
 196         int err;
 197
 198         memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 199         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 200
 201         if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 202                 dev->priv_flags |= IFF_ISATAP;
 203
 204         dev->rtnl_link_ops = &sit_link_ops;
 205
 206         err = register_netdevice(dev);
 207         if (err < 0)
 208                 goto out;
 209
 210         ipip6_tunnel_clone_6rd(dev, sitn);
 211
 212         dev_hold(dev);
 213
 214         ipip6_tunnel_link(sitn, t);
 215         return 0;
 216
 217 out:
 218         return err;
 219 }
 220
 221 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 222                 struct ip_tunnel_parm *parms, int create)
 223 {
 224         __be32 remote = parms->iph.daddr;
 225         __be32 local = parms->iph.saddr;
 226         struct ip_tunnel *t, *nt;
 227         struct ip_tunnel __rcu **tp;
 228         struct net_device *dev;
 229         char name[IFNAMSIZ];
 230         struct sit_net *sitn = net_generic(net, sit_net_id);
 231
 232         for (tp = __ipip6_bucket(sitn, parms);
 233             (t = rtnl_dereference(*tp)) != NULL;
 234              tp = &t->next) {
 235                 if (local == t->parms.iph.saddr &&
 236                     remote == t->parms.iph.daddr &&
 237                     parms->link == t->parms.link) {
 238                         if (create)
 239                                 return NULL;
 240                         else
 241                                 return t;
 242                 }
 243         }
 244         if (!create)
 245                 goto failed;
 246
 247         if (parms->name[0])
 248                 strlcpy(name, parms->name, IFNAMSIZ);
 249         else
 250                 strcpy(name, "sit%d");
 251
 252         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 253                            ipip6_tunnel_setup);
 254         if (!dev)
 255                 return NULL;
 256
 257         dev_net_set(dev, net);
 258
 259         nt = netdev_priv(dev);
 260
 261         nt->parms = *parms;
 262         if (ipip6_tunnel_create(dev) < 0)
 263                 goto failed_free;
 264
 265         return nt;
 266
 267 failed_free:
 268         ipip6_dev_free(dev);
 269 failed:
 270         return NULL;
 271 }
 272
 273 #define for_each_prl_rcu(start)                 \
 274         for (prl = rcu_dereference(start);      \
 275              prl;                               \
 276              prl = rcu_dereference(prl->next))
 277
 278 static struct ip_tunnel_prl_entry *
 279 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 280 {
 281         struct ip_tunnel_prl_entry *prl;
 282
 283         for_each_prl_rcu(t->prl)
 284                 if (prl->addr == addr)
 285                         break;
 286         return prl;
 287
 288 }
 289
 290 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 291                                 struct ip_tunnel_prl __user *a)
 292 {
 293         struct ip_tunnel_prl kprl, *kp;
 294         struct ip_tunnel_prl_entry *prl;
 295         unsigned int cmax, c = 0, ca, len;
 296         int ret = 0;
 297
 298         if (copy_from_user(&kprl, a, sizeof(kprl)))
 299                 return -EFAULT;
 300         cmax = kprl.datalen / sizeof(kprl);
 301         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 302                 cmax = 1;
 303
 304         /* For simple GET or for root users,
 305          * we try harder to allocate.
 306          */
 307         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 308                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 309                 NULL;
 310
 311         rcu_read_lock();
 312
 313         ca = t->prl_count < cmax ? t->prl_count : cmax;
 314
 315         if (!kp) {
 316                 /* We don't try hard to allocate much memory for
 317                  * non-root users.
 318                  * For root users, retry allocating enough memory for
 319                  * the answer.
 320                  */
 321                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 322                 if (!kp) {
 323                         ret = -ENOMEM;
 324                         goto out;
 325                 }
 326         }
 327
 328         c = 0;
 329         for_each_prl_rcu(t->prl) {
 330                 if (c >= cmax)
 331                         break;
 332                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 333                         continue;
 334                 kp[c].addr = prl->addr;
 335                 kp[c].flags = prl->flags;
 336                 c++;
 337                 if (kprl.addr != htonl(INADDR_ANY))
 338                         break;
 339         }
 340 out:
 341         rcu_read_unlock();
 342
 343         len = sizeof(*kp) * c;
 344         ret = 0;
 345         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 346                 ret = -EFAULT;
 347
 348         kfree(kp);
 349
 350         return ret;
 351 }
 352
 353 static int
 354 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 355 {
 356         struct ip_tunnel_prl_entry *p;
 357         int err = 0;
 358
 359         if (a->addr == htonl(INADDR_ANY))
 360                 return -EINVAL;
 361
 362         ASSERT_RTNL();
 363
 364         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 365                 if (p->addr == a->addr) {
 366                         if (chg) {
 367                                 p->flags = a->flags;
 368                                 goto out;
 369                         }
 370                         err = -EEXIST;
 371                         goto out;
 372                 }
 373         }
 374
 375         if (chg) {
 376                 err = -ENXIO;
 377                 goto out;
 378         }
 379
 380         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 381         if (!p) {
 382                 err = -ENOBUFS;
 383                 goto out;
 384         }
 385
 386         p->next = t->prl;
 387         p->addr = a->addr;
 388         p->flags = a->flags;
 389         t->prl_count++;
 390         rcu_assign_pointer(t->prl, p);
 391 out:
 392         return err;
 393 }
 394
 395 static void prl_list_destroy_rcu(struct rcu_head *head)
 396 {
 397         struct ip_tunnel_prl_entry *p, *n;
 398
 399         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 400         do {
 401                 n = rcu_dereference_protected(p->next, 1);
 402                 kfree(p);
 403                 p = n;
 404         } while (p);
 405 }
 406
 407 static int
 408 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 409 {
 410         struct ip_tunnel_prl_entry *x;
 411         struct ip_tunnel_prl_entry __rcu **p;
 412         int err = 0;
 413
 414         ASSERT_RTNL();
 415
 416         if (a && a->addr != htonl(INADDR_ANY)) {
 417                 for (p = &t->prl;
 418                      (x = rtnl_dereference(*p)) != NULL;
 419                      p = &x->next) {
 420                         if (x->addr == a->addr) {
 421                                 *p = x->next;
 422                                 kfree_rcu(x, rcu_head);
 423                                 t->prl_count--;
 424                                 goto out;
 425                         }
 426                 }
 427                 err = -ENXIO;
 428         } else {
 429                 x = rtnl_dereference(t->prl);
 430                 if (x) {
 431                         t->prl_count = 0;
 432                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 433                         t->prl = NULL;
 434                 }
 435         }
 436 out:
 437         return err;
 438 }
 439
 440 static int
 441 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 442 {
 443         struct ip_tunnel_prl_entry *p;
 444         int ok = 1;
 445
 446         rcu_read_lock();
 447         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 448         if (p) {
 449                 if (p->flags & PRL_DEFAULT)
 450                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 451                 else
 452                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 453         } else {
 454                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 455
 456                 if (ipv6_addr_is_isatap(addr6) &&
 457                     (addr6->s6_addr32[3] == iph->saddr) &&
 458                     ipv6_chk_prefix(addr6, t->dev))
 459                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 460                 else
 461                         ok = 0;
 462         }
 463         rcu_read_unlock();
 464         return ok;
 465 }
 466
 467 static void ipip6_tunnel_uninit(struct net_device *dev)
 468 {
 469         struct ip_tunnel *tunnel = netdev_priv(dev);
 470         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 471
 472         if (dev == sitn->fb_tunnel_dev) {
 473                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 474         } else {
 475                 ipip6_tunnel_unlink(sitn, tunnel);
 476                 ipip6_tunnel_del_prl(tunnel, NULL);
 477         }
 478         dst_cache_reset(&tunnel->dst_cache);
 479         dev_put(dev);
 480 }
 481
 482 static int ipip6_err(struct sk_buff *skb, u32 info)
 483 {
 484         const struct iphdr *iph = (const struct iphdr *)skb->data;
 485         const int type = icmp_hdr(skb)->type;
 486         const int code = icmp_hdr(skb)->code;
 487         unsigned int data_len = 0;
 488         struct ip_tunnel *t;
 489         int err;
 490
 491         switch (type) {
 492         default:
 493         case ICMP_PARAMETERPROB:
 494                 return 0;
 495
 496         case ICMP_DEST_UNREACH:
 497                 switch (code) {
 498                 case ICMP_SR_FAILED:
 499                         /* Impossible event. */
 500                         return 0;
 501                 default:
 502                         /* All others are translated to HOST_UNREACH.
 503                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 504                            I believe they are just ether pollution. --ANK
 505                          */
 506                         break;
 507                 }
 508                 break;
 509         case ICMP_TIME_EXCEEDED:
 510                 if (code != ICMP_EXC_TTL)
 511                         return 0;
 512                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 513                 break;
 514         case ICMP_REDIRECT:
 515                 break;
 516         }
 517
 518         err = -ENOENT;
 519
 520         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 521                                 skb->dev,
 522                                 iph->daddr,
 523                                 iph->saddr);
 524         if (!t)
 525                 goto out;
 526
 527         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 528                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 529                                  t->parms.link, 0, IPPROTO_IPV6, 0);
 530                 err = 0;
 531                 goto out;
 532         }
 533         if (type == ICMP_REDIRECT) {
 534                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
 535                               IPPROTO_IPV6, 0);
 536                 err = 0;
 537                 goto out;
 538         }
 539
 540         err = 0;
 541         if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 542                 goto out;
 543
 544         if (t->parms.iph.daddr == 0)
 545                 goto out;
 546
 547         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 548                 goto out;
 549
 550         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 551                 t->err_count++;
 552         else
 553                 t->err_count = 1;
 554         t->err_time = jiffies;
 555 out:
 556         return err;
 557 }
 558
 559 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 560                                   const struct in6_addr *v6addr)
 561 {
 562         __be32 v4embed = 0;
 563         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 564                 return true;
 565         return false;
 566 }
 567
 568 /* Checks if an address matches an address on the tunnel interface.
 569  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 570  * Long story:
 571  * This function is called after we considered the packet as spoofed
 572  * in is_spoofed_6rd.
 573  * We may have a router that is doing NAT for proto 41 packets
 574  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 575  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 576  * function will return true, dropping the packet.
 577  * But, we can still check if is spoofed against the IP
 578  * addresses associated with the interface.
 579  */
 580 static bool only_dnatted(const struct ip_tunnel *tunnel,
 581         const struct in6_addr *v6dst)
 582 {
 583         int prefix_len;
 584
 585 #ifdef CONFIG_IPV6_SIT_6RD
 586         prefix_len = tunnel->ip6rd.prefixlen + 32
 587                 - tunnel->ip6rd.relay_prefixlen;
 588 #else
 589         prefix_len = 48;
 590 #endif
 591         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 592 }
 593
 594 /* Returns true if a packet is spoofed */
 595 static bool packet_is_spoofed(struct sk_buff *skb,
 596                               const struct iphdr *iph,
 597                               struct ip_tunnel *tunnel)
 598 {
 599         const struct ipv6hdr *ipv6h;
 600
 601         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 602                 if (!isatap_chksrc(skb, iph, tunnel))
 603                         return true;
 604
 605                 return false;
 606         }
 607
 608         if (tunnel->dev->flags & IFF_POINTOPOINT)
 609                 return false;
 610
 611         ipv6h = ipv6_hdr(skb);
 612
 613         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 614                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 615                                      &iph->saddr, &ipv6h->saddr,
 616                                      &iph->daddr, &ipv6h->daddr);
 617                 return true;
 618         }
 619
 620         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 621                 return false;
 622
 623         if (only_dnatted(tunnel, &ipv6h->daddr))
 624                 return false;
 625
 626         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 627                              &iph->saddr, &ipv6h->saddr,
 628                              &iph->daddr, &ipv6h->daddr);
 629         return true;
 630 }
 631
 632 static int ipip6_rcv(struct sk_buff *skb)
 633 {
 634         const struct iphdr *iph = ip_hdr(skb);
 635         struct ip_tunnel *tunnel;
 636         int err;
 637
 638         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 639                                      iph->saddr, iph->daddr);
 640         if (tunnel) {
 641                 struct pcpu_sw_netstats *tstats;
 642
 643                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 644                     tunnel->parms.iph.protocol != 0)
 645                         goto out;
 646
 647                 skb->mac_header = skb->network_header;
 648                 skb_reset_network_header(skb);
 649                 IPCB(skb)->flags = 0;
 650                 skb->dev = tunnel->dev;
 651
 652                 if (packet_is_spoofed(skb, iph, tunnel)) {
 653                         tunnel->dev->stats.rx_errors++;
 654                         goto out;
 655                 }
 656
 657                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 658                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
 659                         goto out;
 660
 661                 err = IP_ECN_decapsulate(iph, skb);
 662                 if (unlikely(err)) {
 663                         if (log_ecn_error)
 664                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 665                                                      &iph->saddr, iph->tos);
 666                         if (err > 1) {
 667                                 ++tunnel->dev->stats.rx_frame_errors;
 668                                 ++tunnel->dev->stats.rx_errors;
 669                                 goto out;
 670                         }
 671                 }
 672
 673                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 674                 u64_stats_update_begin(&tstats->syncp);
 675                 tstats->rx_packets++;
 676                 tstats->rx_bytes += skb->len;
 677                 u64_stats_update_end(&tstats->syncp);
 678
 679                 netif_rx(skb);
 680
 681                 return 0;
 682         }
 683
 684         /* no tunnel matched,  let upstream know, ipsec may handle it */
 685         return 1;
 686 out:
 687         kfree_skb(skb);
 688         return 0;
 689 }
 690
 691 static const struct tnl_ptk_info tpi = {
 692         /* no tunnel info required for ipip. */
 693         .proto = htons(ETH_P_IP),
 694 };
 695
 696 static int ipip_rcv(struct sk_buff *skb)
 697 {
 698         const struct iphdr *iph;
 699         struct ip_tunnel *tunnel;
 700
 701         iph = ip_hdr(skb);
 702         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 703                                      iph->saddr, iph->daddr);
 704         if (tunnel) {
 705                 if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 706                     tunnel->parms.iph.protocol != 0)
 707                         goto drop;
 708
 709                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 710                         goto drop;
 711                 if (iptunnel_pull_header(skb, 0, tpi.proto, false))
 712                         goto drop;
 713                 return ip_tunnel_rcv(tunnel, skb, &tpi, NULL, log_ecn_error);
 714         }
 715
 716         return 1;
 717
 718 drop:
 719         kfree_skb(skb);
 720         return 0;
 721 }
 722
 723 /*
 724  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 725  * stores the embedded IPv4 address in v4dst and returns true.
 726  */
 727 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 728                       __be32 *v4dst)
 729 {
 730 #ifdef CONFIG_IPV6_SIT_6RD
 731         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 732                               tunnel->ip6rd.prefixlen)) {
 733                 unsigned int pbw0, pbi0;
 734                 int pbi1;
 735                 u32 d;
 736
 737                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 738                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 739
 740                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 741                     tunnel->ip6rd.relay_prefixlen;
 742
 743                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 744                 if (pbi1 > 0)
 745                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 746                              (32 - pbi1);
 747
 748                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 749                 return true;
 750         }
 751 #else
 752         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 753                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 754                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 755                 return true;
 756         }
 757 #endif
 758         return false;
 759 }
 760
 761 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 762                              const struct in6_addr *v6dst)
 763 {
 764         __be32 dst = 0;
 765         check_6rd(tunnel, v6dst, &dst);
 766         return dst;
 767 }
 768
 769 /*
 770  *      This function assumes it is being called from dev_queue_xmit()
 771  *      and that skb is filled properly by that function.
 772  */
 773
 774 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 775                                      struct net_device *dev)
 776 {
 777         struct ip_tunnel *tunnel = netdev_priv(dev);
 778         const struct iphdr  *tiph = &tunnel->parms.iph;
 779         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 780         u8     tos = tunnel->parms.iph.tos;
 781         __be16 df = tiph->frag_off;
 782         struct rtable *rt;              /* Route to the other host */
 783         struct net_device *tdev;        /* Device to other host */
 784         unsigned int max_headroom;      /* The extra header space needed */
 785         __be32 dst = tiph->daddr;
 786         struct flowi4 fl4;
 787         int    mtu;
 788         const struct in6_addr *addr6;
 789         int addr_type;
 790         u8 ttl;
 791         u8 protocol = IPPROTO_IPV6;
 792         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 793
 794         if (tos == 1)
 795                 tos = ipv6_get_dsfield(iph6);
 796
 797         /* ISATAP (RFC4214) - must come before 6to4 */
 798         if (dev->priv_flags & IFF_ISATAP) {
 799                 struct neighbour *neigh = NULL;
 800                 bool do_tx_error = false;
 801
 802                 if (skb_dst(skb))
 803                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 804
 805                 if (!neigh) {
 806                         net_dbg_ratelimited("nexthop == NULL\n");
 807                         goto tx_error;
 808                 }
 809
 810                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 811                 addr_type = ipv6_addr_type(addr6);
 812
 813                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 814                      ipv6_addr_is_isatap(addr6))
 815                         dst = addr6->s6_addr32[3];
 816                 else
 817                         do_tx_error = true;
 818
 819                 neigh_release(neigh);
 820                 if (do_tx_error)
 821                         goto tx_error;
 822         }
 823
 824         if (!dst)
 825                 dst = try_6rd(tunnel, &iph6->daddr);
 826
 827         if (!dst) {
 828                 struct neighbour *neigh = NULL;
 829                 bool do_tx_error = false;
 830
 831                 if (skb_dst(skb))
 832                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 833
 834                 if (!neigh) {
 835                         net_dbg_ratelimited("nexthop == NULL\n");
 836                         goto tx_error;
 837                 }
 838
 839                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 840                 addr_type = ipv6_addr_type(addr6);
 841
 842                 if (addr_type == IPV6_ADDR_ANY) {
 843                         addr6 = &ipv6_hdr(skb)->daddr;
 844                         addr_type = ipv6_addr_type(addr6);
 845                 }
 846
 847                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 848                         dst = addr6->s6_addr32[3];
 849                 else
 850                         do_tx_error = true;
 851
 852                 neigh_release(neigh);
 853                 if (do_tx_error)
 854                         goto tx_error;
 855         }
 856
 857         rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 858                                    dst, tiph->saddr,
 859                                    0, 0,
 860                                    IPPROTO_IPV6, RT_TOS(tos),
 861                                    tunnel->parms.link);
 862         if (IS_ERR(rt)) {
 863                 dev->stats.tx_carrier_errors++;
 864                 goto tx_error_icmp;
 865         }
 866         if (rt->rt_type != RTN_UNICAST) {
 867                 ip_rt_put(rt);
 868                 dev->stats.tx_carrier_errors++;
 869                 goto tx_error_icmp;
 870         }
 871         tdev = rt->dst.dev;
 872
 873         if (tdev == dev) {
 874                 ip_rt_put(rt);
 875                 dev->stats.collisions++;
 876                 goto tx_error;
 877         }
 878
 879         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 880                 ip_rt_put(rt);
 881                 goto tx_error;
 882         }
 883
 884         if (df) {
 885                 mtu = dst_mtu(&rt->dst) - t_hlen;
 886
 887                 if (mtu < 68) {
 888                         dev->stats.collisions++;
 889                         ip_rt_put(rt);
 890                         goto tx_error;
 891                 }
 892
 893                 if (mtu < IPV6_MIN_MTU) {
 894                         mtu = IPV6_MIN_MTU;
 895                         df = 0;
 896                 }
 897
 898                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 899                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 900
 901                 if (skb->len > mtu && !skb_is_gso(skb)) {
 902                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 903                         ip_rt_put(rt);
 904                         goto tx_error;
 905                 }
 906         }
 907
 908         if (tunnel->err_count > 0) {
 909                 if (time_before(jiffies,
 910                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 911                         tunnel->err_count--;
 912                         dst_link_failure(skb);
 913                 } else
 914                         tunnel->err_count = 0;
 915         }
 916
 917         /*
 918          * Okay, now see if we can stuff it in the buffer as-is.
 919          */
 920         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 921
 922         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 923             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 924                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 925                 if (!new_skb) {
 926                         ip_rt_put(rt);
 927                         dev->stats.tx_dropped++;
 928                         kfree_skb(skb);
 929                         return NETDEV_TX_OK;
 930                 }
 931                 if (skb->sk)
 932                         skb_set_owner_w(new_skb, skb->sk);
 933                 dev_kfree_skb(skb);
 934                 skb = new_skb;
 935                 iph6 = ipv6_hdr(skb);
 936         }
 937         ttl = tiph->ttl;
 938         if (ttl == 0)
 939                 ttl = iph6->hop_limit;
 940         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 941
 942         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 943                 ip_rt_put(rt);
 944                 goto tx_error;
 945         }
 946
 947         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 948
 949         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 950                       df, !net_eq(tunnel->net, dev_net(dev)));
 951         return NETDEV_TX_OK;
 952
 953 tx_error_icmp:
 954         dst_link_failure(skb);
 955 tx_error:
 956         kfree_skb(skb);
 957         dev->stats.tx_errors++;
 958         return NETDEV_TX_OK;
 959 }
 960
 961 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 962 {
 963         struct ip_tunnel *tunnel = netdev_priv(dev);
 964         const struct iphdr  *tiph = &tunnel->parms.iph;
 965
 966         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
 967                 goto tx_error;
 968
 969         skb_set_inner_ipproto(skb, IPPROTO_IPIP);
 970
 971         ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
 972         return NETDEV_TX_OK;
 973 tx_error:
 974         kfree_skb(skb);
 975         dev->stats.tx_errors++;
 976         return NETDEV_TX_OK;
 977 }
 978
 979 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
 980                                    struct net_device *dev)
 981 {
 982         switch (skb->protocol) {
 983         case htons(ETH_P_IP):
 984                 ipip_tunnel_xmit(skb, dev);
 985                 break;
 986         case htons(ETH_P_IPV6):
 987                 ipip6_tunnel_xmit(skb, dev);
 988                 break;
 989         default:
 990                 goto tx_err;
 991         }
 992
 993         return NETDEV_TX_OK;
 994
 995 tx_err:
 996         dev->stats.tx_errors++;
 997         kfree_skb(skb);
 998         return NETDEV_TX_OK;
 999
1000 }
1001
1002 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1003 {
1004         struct net_device *tdev = NULL;
1005         struct ip_tunnel *tunnel;
1006         const struct iphdr *iph;
1007         struct flowi4 fl4;
1008
1009         tunnel = netdev_priv(dev);
1010         iph = &tunnel->parms.iph;
1011
1012         if (iph->daddr) {
1013                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1014                                                           NULL,
1015                                                           iph->daddr, iph->saddr,
1016                                                           0, 0,
1017                                                           IPPROTO_IPV6,
1018                                                           RT_TOS(iph->tos),
1019                                                           tunnel->parms.link);
1020
1021                 if (!IS_ERR(rt)) {
1022                         tdev = rt->dst.dev;
1023                         ip_rt_put(rt);
1024                 }
1025                 dev->flags |= IFF_POINTOPOINT;
1026         }
1027
1028         if (!tdev && tunnel->parms.link)
1029                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1030
1031         if (tdev) {
1032                 int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1033
1034                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1035                 dev->mtu = tdev->mtu - t_hlen;
1036                 if (dev->mtu < IPV6_MIN_MTU)
1037                         dev->mtu = IPV6_MIN_MTU;
1038         }
1039 }
1040
1041 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1042 {
1043         struct net *net = t->net;
1044         struct sit_net *sitn = net_generic(net, sit_net_id);
1045
1046         ipip6_tunnel_unlink(sitn, t);
1047         synchronize_net();
1048         t->parms.iph.saddr = p->iph.saddr;
1049         t->parms.iph.daddr = p->iph.daddr;
1050         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1051         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1052         ipip6_tunnel_link(sitn, t);
1053         t->parms.iph.ttl = p->iph.ttl;
1054         t->parms.iph.tos = p->iph.tos;
1055         if (t->parms.link != p->link) {
1056                 t->parms.link = p->link;
1057                 ipip6_tunnel_bind_dev(t->dev);
1058         }
1059         dst_cache_reset(&t->dst_cache);
1060         netdev_state_change(t->dev);
1061 }
1062
1063 #ifdef CONFIG_IPV6_SIT_6RD
1064 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1065                                    struct ip_tunnel_6rd *ip6rd)
1066 {
1067         struct in6_addr prefix;
1068         __be32 relay_prefix;
1069
1070         if (ip6rd->relay_prefixlen > 32 ||
1071             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1072                 return -EINVAL;
1073
1074         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1075         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1076                 return -EINVAL;
1077         if (ip6rd->relay_prefixlen)
1078                 relay_prefix = ip6rd->relay_prefix &
1079                                htonl(0xffffffffUL <<
1080                                      (32 - ip6rd->relay_prefixlen));
1081         else
1082                 relay_prefix = 0;
1083         if (relay_prefix != ip6rd->relay_prefix)
1084                 return -EINVAL;
1085
1086         t->ip6rd.prefix = prefix;
1087         t->ip6rd.relay_prefix = relay_prefix;
1088         t->ip6rd.prefixlen = ip6rd->prefixlen;
1089         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1090         dst_cache_reset(&t->dst_cache);
1091         netdev_state_change(t->dev);
1092         return 0;
1093 }
1094 #endif
1095
1096 static int
1097 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1098 {
1099         int err = 0;
1100         struct ip_tunnel_parm p;
1101         struct ip_tunnel_prl prl;
1102         struct ip_tunnel *t = netdev_priv(dev);
1103         struct net *net = t->net;
1104         struct sit_net *sitn = net_generic(net, sit_net_id);
1105 #ifdef CONFIG_IPV6_SIT_6RD
1106         struct ip_tunnel_6rd ip6rd;
1107 #endif
1108
1109         switch (cmd) {
1110         case SIOCGETTUNNEL:
1111 #ifdef CONFIG_IPV6_SIT_6RD
1112         case SIOCGET6RD:
1113 #endif
1114                 if (dev == sitn->fb_tunnel_dev) {
1115                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1116                                 err = -EFAULT;
1117                                 break;
1118                         }
1119                         t = ipip6_tunnel_locate(net, &p, 0);
1120                         if (!t)
1121                                 t = netdev_priv(dev);
1122                 }
1123
1124                 err = -EFAULT;
1125                 if (cmd == SIOCGETTUNNEL) {
1126                         memcpy(&p, &t->parms, sizeof(p));
1127                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1128                                          sizeof(p)))
1129                                 goto done;
1130 #ifdef CONFIG_IPV6_SIT_6RD
1131                 } else {
1132                         ip6rd.prefix = t->ip6rd.prefix;
1133                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1134                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1135                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1136                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1137                                          sizeof(ip6rd)))
1138                                 goto done;
1139 #endif
1140                 }
1141                 err = 0;
1142                 break;
1143
1144         case SIOCADDTUNNEL:
1145         case SIOCCHGTUNNEL:
1146                 err = -EPERM;
1147                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1148                         goto done;
1149
1150                 err = -EFAULT;
1151                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1152                         goto done;
1153
1154                 err = -EINVAL;
1155                 if (p.iph.protocol != IPPROTO_IPV6 &&
1156                     p.iph.protocol != IPPROTO_IPIP &&
1157                     p.iph.protocol != 0)
1158                         goto done;
1159                 if (p.iph.version != 4 ||
1160                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1161                         goto done;
1162                 if (p.iph.ttl)
1163                         p.iph.frag_off |= htons(IP_DF);
1164
1165                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1166
1167                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1168                         if (t) {
1169                                 if (t->dev != dev) {
1170                                         err = -EEXIST;
1171                                         break;
1172                                 }
1173                         } else {
1174                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1175                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1176                                         err = -EINVAL;
1177                                         break;
1178                                 }
1179                                 t = netdev_priv(dev);
1180                         }
1181
1182                         ipip6_tunnel_update(t, &p);
1183                 }
1184
1185                 if (t) {
1186                         err = 0;
1187                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1188                                 err = -EFAULT;
1189                 } else
1190                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1191                 break;
1192
1193         case SIOCDELTUNNEL:
1194                 err = -EPERM;
1195                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1196                         goto done;
1197
1198                 if (dev == sitn->fb_tunnel_dev) {
1199                         err = -EFAULT;
1200                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1201                                 goto done;
1202                         err = -ENOENT;
1203                         t = ipip6_tunnel_locate(net, &p, 0);
1204                         if (!t)
1205                                 goto done;
1206                         err = -EPERM;
1207                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1208                                 goto done;
1209                         dev = t->dev;
1210                 }
1211                 unregister_netdevice(dev);
1212                 err = 0;
1213                 break;
1214
1215         case SIOCGETPRL:
1216                 err = -EINVAL;
1217                 if (dev == sitn->fb_tunnel_dev)
1218                         goto done;
1219                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1220                 break;
1221
1222         case SIOCADDPRL:
1223         case SIOCDELPRL:
1224         case SIOCCHGPRL:
1225                 err = -EPERM;
1226                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1227                         goto done;
1228                 err = -EINVAL;
1229                 if (dev == sitn->fb_tunnel_dev)
1230                         goto done;
1231                 err = -EFAULT;
1232                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1233                         goto done;
1234
1235                 switch (cmd) {
1236                 case SIOCDELPRL:
1237                         err = ipip6_tunnel_del_prl(t, &prl);
1238                         break;
1239                 case SIOCADDPRL:
1240                 case SIOCCHGPRL:
1241                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1242                         break;
1243                 }
1244                 dst_cache_reset(&t->dst_cache);
1245                 netdev_state_change(dev);
1246                 break;
1247
1248 #ifdef CONFIG_IPV6_SIT_6RD
1249         case SIOCADD6RD:
1250         case SIOCCHG6RD:
1251         case SIOCDEL6RD:
1252                 err = -EPERM;
1253                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1254                         goto done;
1255
1256                 err = -EFAULT;
1257                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1258                                    sizeof(ip6rd)))
1259                         goto done;
1260
1261                 if (cmd != SIOCDEL6RD) {
1262                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1263                         if (err < 0)
1264                                 goto done;
1265                 } else
1266                         ipip6_tunnel_clone_6rd(dev, sitn);
1267
1268                 err = 0;
1269                 break;
1270 #endif
1271
1272         default:
1273                 err = -EINVAL;
1274         }
1275
1276 done:
1277         return err;
1278 }
1279
1280 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1281 {
1282         struct ip_tunnel *tunnel = netdev_priv(dev);
1283         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1284
1285         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - t_hlen)
1286                 return -EINVAL;
1287         dev->mtu = new_mtu;
1288         return 0;
1289 }
1290
1291 static const struct net_device_ops ipip6_netdev_ops = {
1292         .ndo_init       = ipip6_tunnel_init,
1293         .ndo_uninit     = ipip6_tunnel_uninit,
1294         .ndo_start_xmit = sit_tunnel_xmit,
1295         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1296         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1297         .ndo_get_stats64 = ip_tunnel_get_stats64,
1298         .ndo_get_iflink = ip_tunnel_get_iflink,
1299 };
1300
1301 static void ipip6_dev_free(struct net_device *dev)
1302 {
1303         struct ip_tunnel *tunnel = netdev_priv(dev);
1304
1305         dst_cache_destroy(&tunnel->dst_cache);
1306         free_percpu(dev->tstats);
1307         free_netdev(dev);
1308 }
1309
1310 #define SIT_FEATURES (NETIF_F_SG           | \
1311                       NETIF_F_FRAGLIST     | \
1312                       NETIF_F_HIGHDMA      | \
1313                       NETIF_F_GSO_SOFTWARE | \
1314                       NETIF_F_HW_CSUM)
1315
1316 static void ipip6_tunnel_setup(struct net_device *dev)
1317 {
1318         struct ip_tunnel *tunnel = netdev_priv(dev);
1319         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1320
1321         dev->netdev_ops         = &ipip6_netdev_ops;
1322         dev->destructor         = ipip6_dev_free;
1323
1324         dev->type               = ARPHRD_SIT;
1325         dev->hard_header_len    = LL_MAX_HEADER + t_hlen;
1326         dev->mtu                = ETH_DATA_LEN - t_hlen;
1327         dev->flags              = IFF_NOARP;
1328         netif_keep_dst(dev);
1329         dev->addr_len           = 4;
1330         dev->features           |= NETIF_F_LLTX;
1331         dev->features           |= SIT_FEATURES;
1332         dev->hw_features        |= SIT_FEATURES;
1333 }
1334
1335 static int ipip6_tunnel_init(struct net_device *dev)
1336 {
1337         struct ip_tunnel *tunnel = netdev_priv(dev);
1338         int err;
1339
1340         tunnel->dev = dev;
1341         tunnel->net = dev_net(dev);
1342         strcpy(tunnel->parms.name, dev->name);
1343
1344         ipip6_tunnel_bind_dev(dev);
1345         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1346         if (!dev->tstats)
1347                 return -ENOMEM;
1348
1349         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1350         if (err) {
1351                 free_percpu(dev->tstats);
1352                 return err;
1353         }
1354
1355         return 0;
1356 }
1357
1358 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1359 {
1360         struct ip_tunnel *tunnel = netdev_priv(dev);
1361         struct iphdr *iph = &tunnel->parms.iph;
1362         struct net *net = dev_net(dev);
1363         struct sit_net *sitn = net_generic(net, sit_net_id);
1364
1365         iph->version            = 4;
1366         iph->protocol           = IPPROTO_IPV6;
1367         iph->ihl                = 5;
1368         iph->ttl                = 64;
1369
1370         dev_hold(dev);
1371         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1372 }
1373
1374 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1375 {
1376         u8 proto;
1377
1378         if (!data || !data[IFLA_IPTUN_PROTO])
1379                 return 0;
1380
1381         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1382         if (proto != IPPROTO_IPV6 &&
1383             proto != IPPROTO_IPIP &&
1384             proto != 0)
1385                 return -EINVAL;
1386
1387         return 0;
1388 }
1389
1390 static void ipip6_netlink_parms(struct nlattr *data[],
1391                                 struct ip_tunnel_parm *parms)
1392 {
1393         memset(parms, 0, sizeof(*parms));
1394
1395         parms->iph.version = 4;
1396         parms->iph.protocol = IPPROTO_IPV6;
1397         parms->iph.ihl = 5;
1398         parms->iph.ttl = 64;
1399
1400         if (!data)
1401                 return;
1402
1403         if (data[IFLA_IPTUN_LINK])
1404                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1405
1406         if (data[IFLA_IPTUN_LOCAL])
1407                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1408
1409         if (data[IFLA_IPTUN_REMOTE])
1410                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1411
1412         if (data[IFLA_IPTUN_TTL]) {
1413                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1414                 if (parms->iph.ttl)
1415                         parms->iph.frag_off = htons(IP_DF);
1416         }
1417
1418         if (data[IFLA_IPTUN_TOS])
1419                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1420
1421         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1422                 parms->iph.frag_off = htons(IP_DF);
1423
1424         if (data[IFLA_IPTUN_FLAGS])
1425                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1426
1427         if (data[IFLA_IPTUN_PROTO])
1428                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1429
1430 }
1431
1432 /* This function returns true when ENCAP attributes are present in the nl msg */
1433 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1434                                       struct ip_tunnel_encap *ipencap)
1435 {
1436         bool ret = false;
1437
1438         memset(ipencap, 0, sizeof(*ipencap));
1439
1440         if (!data)
1441                 return ret;
1442
1443         if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1444                 ret = true;
1445                 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1446         }
1447
1448         if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1449                 ret = true;
1450                 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1451         }
1452
1453         if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1454                 ret = true;
1455                 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1456         }
1457
1458         if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1459                 ret = true;
1460                 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1461         }
1462
1463         return ret;
1464 }
1465
1466 #ifdef CONFIG_IPV6_SIT_6RD
1467 /* This function returns true when 6RD attributes are present in the nl msg */
1468 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1469                                     struct ip_tunnel_6rd *ip6rd)
1470 {
1471         bool ret = false;
1472         memset(ip6rd, 0, sizeof(*ip6rd));
1473
1474         if (!data)
1475                 return ret;
1476
1477         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1478                 ret = true;
1479                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1480         }
1481
1482         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1483                 ret = true;
1484                 ip6rd->relay_prefix =
1485                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1486         }
1487
1488         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1489                 ret = true;
1490                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1491         }
1492
1493         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1494                 ret = true;
1495                 ip6rd->relay_prefixlen =
1496                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1497         }
1498
1499         return ret;
1500 }
1501 #endif
1502
1503 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1504                          struct nlattr *tb[], struct nlattr *data[])
1505 {
1506         struct net *net = dev_net(dev);
1507         struct ip_tunnel *nt;
1508         struct ip_tunnel_encap ipencap;
1509 #ifdef CONFIG_IPV6_SIT_6RD
1510         struct ip_tunnel_6rd ip6rd;
1511 #endif
1512         int err;
1513
1514         nt = netdev_priv(dev);
1515
1516         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1517                 err = ip_tunnel_encap_setup(nt, &ipencap);
1518                 if (err < 0)
1519                         return err;
1520         }
1521
1522         ipip6_netlink_parms(data, &nt->parms);
1523
1524         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1525                 return -EEXIST;
1526
1527         err = ipip6_tunnel_create(dev);
1528         if (err < 0)
1529                 return err;
1530
1531 #ifdef CONFIG_IPV6_SIT_6RD
1532         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1533                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1534 #endif
1535
1536         return err;
1537 }
1538
1539 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1540                           struct nlattr *data[])
1541 {
1542         struct ip_tunnel *t = netdev_priv(dev);
1543         struct ip_tunnel_parm p;
1544         struct ip_tunnel_encap ipencap;
1545         struct net *net = t->net;
1546         struct sit_net *sitn = net_generic(net, sit_net_id);
1547 #ifdef CONFIG_IPV6_SIT_6RD
1548         struct ip_tunnel_6rd ip6rd;
1549 #endif
1550         int err;
1551
1552         if (dev == sitn->fb_tunnel_dev)
1553                 return -EINVAL;
1554
1555         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1556                 err = ip_tunnel_encap_setup(t, &ipencap);
1557                 if (err < 0)
1558                         return err;
1559         }
1560
1561         ipip6_netlink_parms(data, &p);
1562
1563         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1564             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1565                 return -EINVAL;
1566
1567         t = ipip6_tunnel_locate(net, &p, 0);
1568
1569         if (t) {
1570                 if (t->dev != dev)
1571                         return -EEXIST;
1572         } else
1573                 t = netdev_priv(dev);
1574
1575         ipip6_tunnel_update(t, &p);
1576
1577 #ifdef CONFIG_IPV6_SIT_6RD
1578         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1579                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1580 #endif
1581
1582         return 0;
1583 }
1584
1585 static size_t ipip6_get_size(const struct net_device *dev)
1586 {
1587         return
1588                 /* IFLA_IPTUN_LINK */
1589                 nla_total_size(4) +
1590                 /* IFLA_IPTUN_LOCAL */
1591                 nla_total_size(4) +
1592                 /* IFLA_IPTUN_REMOTE */
1593                 nla_total_size(4) +
1594                 /* IFLA_IPTUN_TTL */
1595                 nla_total_size(1) +
1596                 /* IFLA_IPTUN_TOS */
1597                 nla_total_size(1) +
1598                 /* IFLA_IPTUN_PMTUDISC */
1599                 nla_total_size(1) +
1600                 /* IFLA_IPTUN_FLAGS */
1601                 nla_total_size(2) +
1602                 /* IFLA_IPTUN_PROTO */
1603                 nla_total_size(1) +
1604 #ifdef CONFIG_IPV6_SIT_6RD
1605                 /* IFLA_IPTUN_6RD_PREFIX */
1606                 nla_total_size(sizeof(struct in6_addr)) +
1607                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1608                 nla_total_size(4) +
1609                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1610                 nla_total_size(2) +
1611                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1612                 nla_total_size(2) +
1613 #endif
1614                 /* IFLA_IPTUN_ENCAP_TYPE */
1615                 nla_total_size(2) +
1616                 /* IFLA_IPTUN_ENCAP_FLAGS */
1617                 nla_total_size(2) +
1618                 /* IFLA_IPTUN_ENCAP_SPORT */
1619                 nla_total_size(2) +
1620                 /* IFLA_IPTUN_ENCAP_DPORT */
1621                 nla_total_size(2) +
1622                 0;
1623 }
1624
1625 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1626 {
1627         struct ip_tunnel *tunnel = netdev_priv(dev);
1628         struct ip_tunnel_parm *parm = &tunnel->parms;
1629
1630         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1631             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1632             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1633             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1634             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1635             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1636                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1637             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1638             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1639                 goto nla_put_failure;
1640
1641 #ifdef CONFIG_IPV6_SIT_6RD
1642         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1643                              &tunnel->ip6rd.prefix) ||
1644             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1645                             tunnel->ip6rd.relay_prefix) ||
1646             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1647                         tunnel->ip6rd.prefixlen) ||
1648             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1649                         tunnel->ip6rd.relay_prefixlen))
1650                 goto nla_put_failure;
1651 #endif
1652
1653         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1654                         tunnel->encap.type) ||
1655             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1656                         tunnel->encap.sport) ||
1657             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1658                         tunnel->encap.dport) ||
1659             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1660                         tunnel->encap.flags))
1661                 goto nla_put_failure;
1662
1663         return 0;
1664
1665 nla_put_failure:
1666         return -EMSGSIZE;
1667 }
1668
1669 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1670         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1671         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1672         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1673         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1674         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1675         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1676         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1677         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1678 #ifdef CONFIG_IPV6_SIT_6RD
1679         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1680         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1681         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1682         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1683 #endif
1684         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1685         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1686         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1687         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1688 };
1689
1690 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1691 {
1692         struct net *net = dev_net(dev);
1693         struct sit_net *sitn = net_generic(net, sit_net_id);
1694
1695         if (dev != sitn->fb_tunnel_dev)
1696                 unregister_netdevice_queue(dev, head);
1697 }
1698
1699 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1700         .kind           = "sit",
1701         .maxtype        = IFLA_IPTUN_MAX,
1702         .policy         = ipip6_policy,
1703         .priv_size      = sizeof(struct ip_tunnel),
1704         .setup          = ipip6_tunnel_setup,
1705         .validate       = ipip6_validate,
1706         .newlink        = ipip6_newlink,
1707         .changelink     = ipip6_changelink,
1708         .get_size       = ipip6_get_size,
1709         .fill_info      = ipip6_fill_info,
1710         .dellink        = ipip6_dellink,
1711         .get_link_net   = ip_tunnel_get_link_net,
1712 };
1713
1714 static struct xfrm_tunnel sit_handler __read_mostly = {
1715         .handler        =       ipip6_rcv,
1716         .err_handler    =       ipip6_err,
1717         .priority       =       1,
1718 };
1719
1720 static struct xfrm_tunnel ipip_handler __read_mostly = {
1721         .handler        =       ipip_rcv,
1722         .err_handler    =       ipip6_err,
1723         .priority       =       2,
1724 };
1725
1726 static void __net_exit sit_destroy_tunnels(struct net *net,
1727                                            struct list_head *head)
1728 {
1729         struct sit_net *sitn = net_generic(net, sit_net_id);
1730         struct net_device *dev, *aux;
1731         int prio;
1732
1733         for_each_netdev_safe(net, dev, aux)
1734                 if (dev->rtnl_link_ops == &sit_link_ops)
1735                         unregister_netdevice_queue(dev, head);
1736
1737         for (prio = 1; prio < 4; prio++) {
1738                 int h;
1739                 for (h = 0; h < HASH_SIZE; h++) {
1740                         struct ip_tunnel *t;
1741
1742                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1743                         while (t) {
1744                                 /* If dev is in the same netns, it has already
1745                                  * been added to the list by the previous loop.
1746                                  */
1747                                 if (!net_eq(dev_net(t->dev), net))
1748                                         unregister_netdevice_queue(t->dev,
1749                                                                    head);
1750                                 t = rtnl_dereference(t->next);
1751                         }
1752                 }
1753         }
1754 }
1755
1756 static int __net_init sit_init_net(struct net *net)
1757 {
1758         struct sit_net *sitn = net_generic(net, sit_net_id);
1759         struct ip_tunnel *t;
1760         int err;
1761
1762         sitn->tunnels[0] = sitn->tunnels_wc;
1763         sitn->tunnels[1] = sitn->tunnels_l;
1764         sitn->tunnels[2] = sitn->tunnels_r;
1765         sitn->tunnels[3] = sitn->tunnels_r_l;
1766
1767         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1768                                            NET_NAME_UNKNOWN,
1769                                            ipip6_tunnel_setup);
1770         if (!sitn->fb_tunnel_dev) {
1771                 err = -ENOMEM;
1772                 goto err_alloc_dev;
1773         }
1774         dev_net_set(sitn->fb_tunnel_dev, net);
1775         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1776         /* FB netdevice is special: we have one, and only one per netns.
1777          * Allowing to move it to another netns is clearly unsafe.
1778          */
1779         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1780
1781         err = register_netdev(sitn->fb_tunnel_dev);
1782         if (err)
1783                 goto err_reg_dev;
1784
1785         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1786         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1787
1788         t = netdev_priv(sitn->fb_tunnel_dev);
1789
1790         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1791         return 0;
1792
1793 err_reg_dev:
1794         ipip6_dev_free(sitn->fb_tunnel_dev);
1795 err_alloc_dev:
1796         return err;
1797 }
1798
1799 static void __net_exit sit_exit_net(struct net *net)
1800 {
1801         LIST_HEAD(list);
1802
1803         rtnl_lock();
1804         sit_destroy_tunnels(net, &list);
1805         unregister_netdevice_many(&list);
1806         rtnl_unlock();
1807 }
1808
1809 static struct pernet_operations sit_net_ops = {
1810         .init = sit_init_net,
1811         .exit = sit_exit_net,
1812         .id   = &sit_net_id,
1813         .size = sizeof(struct sit_net),
1814 };
1815
1816 static void __exit sit_cleanup(void)
1817 {
1818         rtnl_link_unregister(&sit_link_ops);
1819         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1820         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1821
1822         unregister_pernet_device(&sit_net_ops);
1823         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1824 }
1825
1826 static int __init sit_init(void)
1827 {
1828         int err;
1829
1830         pr_info("IPv6 over IPv4 tunneling driver\n");
1831
1832         err = register_pernet_device(&sit_net_ops);
1833         if (err < 0)
1834                 return err;
1835         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1836         if (err < 0) {
1837                 pr_info("%s: can't register ip6ip4\n", __func__);
1838                 goto xfrm_tunnel_failed;
1839         }
1840         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1841         if (err < 0) {
1842                 pr_info("%s: can't register ip4ip4\n", __func__);
1843                 goto xfrm_tunnel4_failed;
1844         }
1845         err = rtnl_link_register(&sit_link_ops);
1846         if (err < 0)
1847                 goto rtnl_link_failed;
1848
1849 out:
1850         return err;
1851
1852 rtnl_link_failed:
1853         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1854 xfrm_tunnel4_failed:
1855         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1856 xfrm_tunnel_failed:
1857         unregister_pernet_device(&sit_net_ops);
1858         goto out;
1859 }
1860
1861 module_init(sit_init);
1862 module_exit(sit_cleanup);
1863 MODULE_LICENSE("GPL");
1864 MODULE_ALIAS_RTNL_LINK("sit");
1865 MODULE_ALIAS_NETDEV("sit0");