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 <linux/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 IP6_SIT_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 unsigned int sit_net_id __read_mostly;
  80 struct sit_net {
  81         struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
  82         struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
  83         struct ip_tunnel __rcu *tunnels_l[IP6_SIT_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, iph->protocol, 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                               iph->protocol, 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 ipip_tpi = {
 692         /* no tunnel info required for ipip. */
 693         .proto = htons(ETH_P_IP),
 694 };
 695
 696 #if IS_ENABLED(CONFIG_MPLS)
 697 static const struct tnl_ptk_info mplsip_tpi = {
 698         /* no tunnel info required for mplsip. */
 699         .proto = htons(ETH_P_MPLS_UC),
 700 };
 701 #endif
 702
 703 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 704 {
 705         const struct iphdr *iph;
 706         struct ip_tunnel *tunnel;
 707
 708         iph = ip_hdr(skb);
 709         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 710                                      iph->saddr, iph->daddr);
 711         if (tunnel) {
 712                 const struct tnl_ptk_info *tpi;
 713
 714                 if (tunnel->parms.iph.protocol != ipproto &&
 715                     tunnel->parms.iph.protocol != 0)
 716                         goto drop;
 717
 718                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 719                         goto drop;
 720 #if IS_ENABLED(CONFIG_MPLS)
 721                 if (ipproto == IPPROTO_MPLS)
 722                         tpi = &mplsip_tpi;
 723                 else
 724 #endif
 725                         tpi = &ipip_tpi;
 726                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
 727                         goto drop;
 728                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 729         }
 730
 731         return 1;
 732
 733 drop:
 734         kfree_skb(skb);
 735         return 0;
 736 }
 737
 738 static int ipip_rcv(struct sk_buff *skb)
 739 {
 740         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
 741 }
 742
 743 #if IS_ENABLED(CONFIG_MPLS)
 744 static int mplsip_rcv(struct sk_buff *skb)
 745 {
 746         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
 747 }
 748 #endif
 749
 750 /*
 751  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 752  * stores the embedded IPv4 address in v4dst and returns true.
 753  */
 754 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 755                       __be32 *v4dst)
 756 {
 757 #ifdef CONFIG_IPV6_SIT_6RD
 758         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 759                               tunnel->ip6rd.prefixlen)) {
 760                 unsigned int pbw0, pbi0;
 761                 int pbi1;
 762                 u32 d;
 763
 764                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 765                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 766
 767                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 768                     tunnel->ip6rd.relay_prefixlen;
 769
 770                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 771                 if (pbi1 > 0)
 772                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 773                              (32 - pbi1);
 774
 775                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 776                 return true;
 777         }
 778 #else
 779         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 780                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 781                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 782                 return true;
 783         }
 784 #endif
 785         return false;
 786 }
 787
 788 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 789                              const struct in6_addr *v6dst)
 790 {
 791         __be32 dst = 0;
 792         check_6rd(tunnel, v6dst, &dst);
 793         return dst;
 794 }
 795
 796 /*
 797  *      This function assumes it is being called from dev_queue_xmit()
 798  *      and that skb is filled properly by that function.
 799  */
 800
 801 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 802                                      struct net_device *dev)
 803 {
 804         struct ip_tunnel *tunnel = netdev_priv(dev);
 805         const struct iphdr  *tiph = &tunnel->parms.iph;
 806         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 807         u8     tos = tunnel->parms.iph.tos;
 808         __be16 df = tiph->frag_off;
 809         struct rtable *rt;              /* Route to the other host */
 810         struct net_device *tdev;        /* Device to other host */
 811         unsigned int max_headroom;      /* The extra header space needed */
 812         __be32 dst = tiph->daddr;
 813         struct flowi4 fl4;
 814         int    mtu;
 815         const struct in6_addr *addr6;
 816         int addr_type;
 817         u8 ttl;
 818         u8 protocol = IPPROTO_IPV6;
 819         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 820
 821         if (tos == 1)
 822                 tos = ipv6_get_dsfield(iph6);
 823
 824         /* ISATAP (RFC4214) - must come before 6to4 */
 825         if (dev->priv_flags & IFF_ISATAP) {
 826                 struct neighbour *neigh = NULL;
 827                 bool do_tx_error = false;
 828
 829                 if (skb_dst(skb))
 830                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 831
 832                 if (!neigh) {
 833                         net_dbg_ratelimited("nexthop == NULL\n");
 834                         goto tx_error;
 835                 }
 836
 837                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 838                 addr_type = ipv6_addr_type(addr6);
 839
 840                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 841                      ipv6_addr_is_isatap(addr6))
 842                         dst = addr6->s6_addr32[3];
 843                 else
 844                         do_tx_error = true;
 845
 846                 neigh_release(neigh);
 847                 if (do_tx_error)
 848                         goto tx_error;
 849         }
 850
 851         if (!dst)
 852                 dst = try_6rd(tunnel, &iph6->daddr);
 853
 854         if (!dst) {
 855                 struct neighbour *neigh = NULL;
 856                 bool do_tx_error = false;
 857
 858                 if (skb_dst(skb))
 859                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 860
 861                 if (!neigh) {
 862                         net_dbg_ratelimited("nexthop == NULL\n");
 863                         goto tx_error;
 864                 }
 865
 866                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 867                 addr_type = ipv6_addr_type(addr6);
 868
 869                 if (addr_type == IPV6_ADDR_ANY) {
 870                         addr6 = &ipv6_hdr(skb)->daddr;
 871                         addr_type = ipv6_addr_type(addr6);
 872                 }
 873
 874                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 875                         dst = addr6->s6_addr32[3];
 876                 else
 877                         do_tx_error = true;
 878
 879                 neigh_release(neigh);
 880                 if (do_tx_error)
 881                         goto tx_error;
 882         }
 883
 884         rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 885                                    dst, tiph->saddr,
 886                                    0, 0,
 887                                    IPPROTO_IPV6, RT_TOS(tos),
 888                                    tunnel->parms.link);
 889         if (IS_ERR(rt)) {
 890                 dev->stats.tx_carrier_errors++;
 891                 goto tx_error_icmp;
 892         }
 893         if (rt->rt_type != RTN_UNICAST) {
 894                 ip_rt_put(rt);
 895                 dev->stats.tx_carrier_errors++;
 896                 goto tx_error_icmp;
 897         }
 898         tdev = rt->dst.dev;
 899
 900         if (tdev == dev) {
 901                 ip_rt_put(rt);
 902                 dev->stats.collisions++;
 903                 goto tx_error;
 904         }
 905
 906         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 907                 ip_rt_put(rt);
 908                 goto tx_error;
 909         }
 910
 911         if (df) {
 912                 mtu = dst_mtu(&rt->dst) - t_hlen;
 913
 914                 if (mtu < 68) {
 915                         dev->stats.collisions++;
 916                         ip_rt_put(rt);
 917                         goto tx_error;
 918                 }
 919
 920                 if (mtu < IPV6_MIN_MTU) {
 921                         mtu = IPV6_MIN_MTU;
 922                         df = 0;
 923                 }
 924
 925                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 926                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 927
 928                 if (skb->len > mtu && !skb_is_gso(skb)) {
 929                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 930                         ip_rt_put(rt);
 931                         goto tx_error;
 932                 }
 933         }
 934
 935         if (tunnel->err_count > 0) {
 936                 if (time_before(jiffies,
 937                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 938                         tunnel->err_count--;
 939                         dst_link_failure(skb);
 940                 } else
 941                         tunnel->err_count = 0;
 942         }
 943
 944         /*
 945          * Okay, now see if we can stuff it in the buffer as-is.
 946          */
 947         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 948
 949         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 950             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 951                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 952                 if (!new_skb) {
 953                         ip_rt_put(rt);
 954                         dev->stats.tx_dropped++;
 955                         kfree_skb(skb);
 956                         return NETDEV_TX_OK;
 957                 }
 958                 if (skb->sk)
 959                         skb_set_owner_w(new_skb, skb->sk);
 960                 dev_kfree_skb(skb);
 961                 skb = new_skb;
 962                 iph6 = ipv6_hdr(skb);
 963         }
 964         ttl = tiph->ttl;
 965         if (ttl == 0)
 966                 ttl = iph6->hop_limit;
 967         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 968
 969         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 970                 ip_rt_put(rt);
 971                 goto tx_error;
 972         }
 973
 974         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 975
 976         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 977                       df, !net_eq(tunnel->net, dev_net(dev)));
 978         return NETDEV_TX_OK;
 979
 980 tx_error_icmp:
 981         dst_link_failure(skb);
 982 tx_error:
 983         kfree_skb(skb);
 984         dev->stats.tx_errors++;
 985         return NETDEV_TX_OK;
 986 }
 987
 988 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
 989                                      struct net_device *dev, u8 ipproto)
 990 {
 991         struct ip_tunnel *tunnel = netdev_priv(dev);
 992         const struct iphdr  *tiph = &tunnel->parms.iph;
 993
 994         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
 995                 goto tx_error;
 996
 997         skb_set_inner_ipproto(skb, ipproto);
 998
 999         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1000         return NETDEV_TX_OK;
1001 tx_error:
1002         kfree_skb(skb);
1003         dev->stats.tx_errors++;
1004         return NETDEV_TX_OK;
1005 }
1006
1007 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1008                                    struct net_device *dev)
1009 {
1010         switch (skb->protocol) {
1011         case htons(ETH_P_IP):
1012                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1013                 break;
1014         case htons(ETH_P_IPV6):
1015                 ipip6_tunnel_xmit(skb, dev);
1016                 break;
1017 #if IS_ENABLED(CONFIG_MPLS)
1018         case htons(ETH_P_MPLS_UC):
1019                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1020                 break;
1021 #endif
1022         default:
1023                 goto tx_err;
1024         }
1025
1026         return NETDEV_TX_OK;
1027
1028 tx_err:
1029         dev->stats.tx_errors++;
1030         kfree_skb(skb);
1031         return NETDEV_TX_OK;
1032
1033 }
1034
1035 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1036 {
1037         struct net_device *tdev = NULL;
1038         struct ip_tunnel *tunnel;
1039         const struct iphdr *iph;
1040         struct flowi4 fl4;
1041
1042         tunnel = netdev_priv(dev);
1043         iph = &tunnel->parms.iph;
1044
1045         if (iph->daddr) {
1046                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1047                                                           NULL,
1048                                                           iph->daddr, iph->saddr,
1049                                                           0, 0,
1050                                                           IPPROTO_IPV6,
1051                                                           RT_TOS(iph->tos),
1052                                                           tunnel->parms.link);
1053
1054                 if (!IS_ERR(rt)) {
1055                         tdev = rt->dst.dev;
1056                         ip_rt_put(rt);
1057                 }
1058                 dev->flags |= IFF_POINTOPOINT;
1059         }
1060
1061         if (!tdev && tunnel->parms.link)
1062                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1063
1064         if (tdev) {
1065                 int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1066
1067                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1068                 dev->mtu = tdev->mtu - t_hlen;
1069                 if (dev->mtu < IPV6_MIN_MTU)
1070                         dev->mtu = IPV6_MIN_MTU;
1071         }
1072 }
1073
1074 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1075 {
1076         struct net *net = t->net;
1077         struct sit_net *sitn = net_generic(net, sit_net_id);
1078
1079         ipip6_tunnel_unlink(sitn, t);
1080         synchronize_net();
1081         t->parms.iph.saddr = p->iph.saddr;
1082         t->parms.iph.daddr = p->iph.daddr;
1083         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1084         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1085         ipip6_tunnel_link(sitn, t);
1086         t->parms.iph.ttl = p->iph.ttl;
1087         t->parms.iph.tos = p->iph.tos;
1088         if (t->parms.link != p->link) {
1089                 t->parms.link = p->link;
1090                 ipip6_tunnel_bind_dev(t->dev);
1091         }
1092         dst_cache_reset(&t->dst_cache);
1093         netdev_state_change(t->dev);
1094 }
1095
1096 #ifdef CONFIG_IPV6_SIT_6RD
1097 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1098                                    struct ip_tunnel_6rd *ip6rd)
1099 {
1100         struct in6_addr prefix;
1101         __be32 relay_prefix;
1102
1103         if (ip6rd->relay_prefixlen > 32 ||
1104             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1105                 return -EINVAL;
1106
1107         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1108         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1109                 return -EINVAL;
1110         if (ip6rd->relay_prefixlen)
1111                 relay_prefix = ip6rd->relay_prefix &
1112                                htonl(0xffffffffUL <<
1113                                      (32 - ip6rd->relay_prefixlen));
1114         else
1115                 relay_prefix = 0;
1116         if (relay_prefix != ip6rd->relay_prefix)
1117                 return -EINVAL;
1118
1119         t->ip6rd.prefix = prefix;
1120         t->ip6rd.relay_prefix = relay_prefix;
1121         t->ip6rd.prefixlen = ip6rd->prefixlen;
1122         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1123         dst_cache_reset(&t->dst_cache);
1124         netdev_state_change(t->dev);
1125         return 0;
1126 }
1127 #endif
1128
1129 static bool ipip6_valid_ip_proto(u8 ipproto)
1130 {
1131         return ipproto == IPPROTO_IPV6 ||
1132                 ipproto == IPPROTO_IPIP ||
1133 #if IS_ENABLED(CONFIG_MPLS)
1134                 ipproto == IPPROTO_MPLS ||
1135 #endif
1136                 ipproto == 0;
1137 }
1138
1139 static int
1140 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1141 {
1142         int err = 0;
1143         struct ip_tunnel_parm p;
1144         struct ip_tunnel_prl prl;
1145         struct ip_tunnel *t = netdev_priv(dev);
1146         struct net *net = t->net;
1147         struct sit_net *sitn = net_generic(net, sit_net_id);
1148 #ifdef CONFIG_IPV6_SIT_6RD
1149         struct ip_tunnel_6rd ip6rd;
1150 #endif
1151
1152         switch (cmd) {
1153         case SIOCGETTUNNEL:
1154 #ifdef CONFIG_IPV6_SIT_6RD
1155         case SIOCGET6RD:
1156 #endif
1157                 if (dev == sitn->fb_tunnel_dev) {
1158                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1159                                 err = -EFAULT;
1160                                 break;
1161                         }
1162                         t = ipip6_tunnel_locate(net, &p, 0);
1163                         if (!t)
1164                                 t = netdev_priv(dev);
1165                 }
1166
1167                 err = -EFAULT;
1168                 if (cmd == SIOCGETTUNNEL) {
1169                         memcpy(&p, &t->parms, sizeof(p));
1170                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1171                                          sizeof(p)))
1172                                 goto done;
1173 #ifdef CONFIG_IPV6_SIT_6RD
1174                 } else {
1175                         ip6rd.prefix = t->ip6rd.prefix;
1176                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1177                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1178                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1179                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1180                                          sizeof(ip6rd)))
1181                                 goto done;
1182 #endif
1183                 }
1184                 err = 0;
1185                 break;
1186
1187         case SIOCADDTUNNEL:
1188         case SIOCCHGTUNNEL:
1189                 err = -EPERM;
1190                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1191                         goto done;
1192
1193                 err = -EFAULT;
1194                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1195                         goto done;
1196
1197                 err = -EINVAL;
1198                 if (!ipip6_valid_ip_proto(p.iph.protocol))
1199                         goto done;
1200                 if (p.iph.version != 4 ||
1201                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1202                         goto done;
1203                 if (p.iph.ttl)
1204                         p.iph.frag_off |= htons(IP_DF);
1205
1206                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1207
1208                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1209                         if (t) {
1210                                 if (t->dev != dev) {
1211                                         err = -EEXIST;
1212                                         break;
1213                                 }
1214                         } else {
1215                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1216                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1217                                         err = -EINVAL;
1218                                         break;
1219                                 }
1220                                 t = netdev_priv(dev);
1221                         }
1222
1223                         ipip6_tunnel_update(t, &p);
1224                 }
1225
1226                 if (t) {
1227                         err = 0;
1228                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1229                                 err = -EFAULT;
1230                 } else
1231                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1232                 break;
1233
1234         case SIOCDELTUNNEL:
1235                 err = -EPERM;
1236                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1237                         goto done;
1238
1239                 if (dev == sitn->fb_tunnel_dev) {
1240                         err = -EFAULT;
1241                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1242                                 goto done;
1243                         err = -ENOENT;
1244                         t = ipip6_tunnel_locate(net, &p, 0);
1245                         if (!t)
1246                                 goto done;
1247                         err = -EPERM;
1248                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1249                                 goto done;
1250                         dev = t->dev;
1251                 }
1252                 unregister_netdevice(dev);
1253                 err = 0;
1254                 break;
1255
1256         case SIOCGETPRL:
1257                 err = -EINVAL;
1258                 if (dev == sitn->fb_tunnel_dev)
1259                         goto done;
1260                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1261                 break;
1262
1263         case SIOCADDPRL:
1264         case SIOCDELPRL:
1265         case SIOCCHGPRL:
1266                 err = -EPERM;
1267                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1268                         goto done;
1269                 err = -EINVAL;
1270                 if (dev == sitn->fb_tunnel_dev)
1271                         goto done;
1272                 err = -EFAULT;
1273                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1274                         goto done;
1275
1276                 switch (cmd) {
1277                 case SIOCDELPRL:
1278                         err = ipip6_tunnel_del_prl(t, &prl);
1279                         break;
1280                 case SIOCADDPRL:
1281                 case SIOCCHGPRL:
1282                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1283                         break;
1284                 }
1285                 dst_cache_reset(&t->dst_cache);
1286                 netdev_state_change(dev);
1287                 break;
1288
1289 #ifdef CONFIG_IPV6_SIT_6RD
1290         case SIOCADD6RD:
1291         case SIOCCHG6RD:
1292         case SIOCDEL6RD:
1293                 err = -EPERM;
1294                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1295                         goto done;
1296
1297                 err = -EFAULT;
1298                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1299                                    sizeof(ip6rd)))
1300                         goto done;
1301
1302                 if (cmd != SIOCDEL6RD) {
1303                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1304                         if (err < 0)
1305                                 goto done;
1306                 } else
1307                         ipip6_tunnel_clone_6rd(dev, sitn);
1308
1309                 err = 0;
1310                 break;
1311 #endif
1312
1313         default:
1314                 err = -EINVAL;
1315         }
1316
1317 done:
1318         return err;
1319 }
1320
1321 static const struct net_device_ops ipip6_netdev_ops = {
1322         .ndo_init       = ipip6_tunnel_init,
1323         .ndo_uninit     = ipip6_tunnel_uninit,
1324         .ndo_start_xmit = sit_tunnel_xmit,
1325         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1326         .ndo_get_stats64 = ip_tunnel_get_stats64,
1327         .ndo_get_iflink = ip_tunnel_get_iflink,
1328 };
1329
1330 static void ipip6_dev_free(struct net_device *dev)
1331 {
1332         struct ip_tunnel *tunnel = netdev_priv(dev);
1333
1334         dst_cache_destroy(&tunnel->dst_cache);
1335         free_percpu(dev->tstats);
1336         free_netdev(dev);
1337 }
1338
1339 #define SIT_FEATURES (NETIF_F_SG           | \
1340                       NETIF_F_FRAGLIST     | \
1341                       NETIF_F_HIGHDMA      | \
1342                       NETIF_F_GSO_SOFTWARE | \
1343                       NETIF_F_HW_CSUM)
1344
1345 static void ipip6_tunnel_setup(struct net_device *dev)
1346 {
1347         struct ip_tunnel *tunnel = netdev_priv(dev);
1348         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1349
1350         dev->netdev_ops         = &ipip6_netdev_ops;
1351         dev->destructor         = ipip6_dev_free;
1352
1353         dev->type               = ARPHRD_SIT;
1354         dev->hard_header_len    = LL_MAX_HEADER + t_hlen;
1355         dev->mtu                = ETH_DATA_LEN - t_hlen;
1356         dev->min_mtu            = IPV6_MIN_MTU;
1357         dev->max_mtu            = 0xFFF8 - t_hlen;
1358         dev->flags              = IFF_NOARP;
1359         netif_keep_dst(dev);
1360         dev->addr_len           = 4;
1361         dev->features           |= NETIF_F_LLTX;
1362         dev->features           |= SIT_FEATURES;
1363         dev->hw_features        |= SIT_FEATURES;
1364 }
1365
1366 static int ipip6_tunnel_init(struct net_device *dev)
1367 {
1368         struct ip_tunnel *tunnel = netdev_priv(dev);
1369         int err;
1370
1371         tunnel->dev = dev;
1372         tunnel->net = dev_net(dev);
1373         strcpy(tunnel->parms.name, dev->name);
1374
1375         ipip6_tunnel_bind_dev(dev);
1376         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1377         if (!dev->tstats)
1378                 return -ENOMEM;
1379
1380         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1381         if (err) {
1382                 free_percpu(dev->tstats);
1383                 return err;
1384         }
1385
1386         return 0;
1387 }
1388
1389 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1390 {
1391         struct ip_tunnel *tunnel = netdev_priv(dev);
1392         struct iphdr *iph = &tunnel->parms.iph;
1393         struct net *net = dev_net(dev);
1394         struct sit_net *sitn = net_generic(net, sit_net_id);
1395
1396         iph->version            = 4;
1397         iph->protocol           = IPPROTO_IPV6;
1398         iph->ihl                = 5;
1399         iph->ttl                = 64;
1400
1401         dev_hold(dev);
1402         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1403 }
1404
1405 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1406 {
1407         u8 proto;
1408
1409         if (!data || !data[IFLA_IPTUN_PROTO])
1410                 return 0;
1411
1412         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1413         if (!ipip6_valid_ip_proto(proto))
1414                 return -EINVAL;
1415
1416         return 0;
1417 }
1418
1419 static void ipip6_netlink_parms(struct nlattr *data[],
1420                                 struct ip_tunnel_parm *parms)
1421 {
1422         memset(parms, 0, sizeof(*parms));
1423
1424         parms->iph.version = 4;
1425         parms->iph.protocol = IPPROTO_IPV6;
1426         parms->iph.ihl = 5;
1427         parms->iph.ttl = 64;
1428
1429         if (!data)
1430                 return;
1431
1432         if (data[IFLA_IPTUN_LINK])
1433                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1434
1435         if (data[IFLA_IPTUN_LOCAL])
1436                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1437
1438         if (data[IFLA_IPTUN_REMOTE])
1439                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1440
1441         if (data[IFLA_IPTUN_TTL]) {
1442                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1443                 if (parms->iph.ttl)
1444                         parms->iph.frag_off = htons(IP_DF);
1445         }
1446
1447         if (data[IFLA_IPTUN_TOS])
1448                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1449
1450         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1451                 parms->iph.frag_off = htons(IP_DF);
1452
1453         if (data[IFLA_IPTUN_FLAGS])
1454                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1455
1456         if (data[IFLA_IPTUN_PROTO])
1457                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1458
1459 }
1460
1461 /* This function returns true when ENCAP attributes are present in the nl msg */
1462 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1463                                       struct ip_tunnel_encap *ipencap)
1464 {
1465         bool ret = false;
1466
1467         memset(ipencap, 0, sizeof(*ipencap));
1468
1469         if (!data)
1470                 return ret;
1471
1472         if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1473                 ret = true;
1474                 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1475         }
1476
1477         if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1478                 ret = true;
1479                 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1480         }
1481
1482         if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1483                 ret = true;
1484                 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1485         }
1486
1487         if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1488                 ret = true;
1489                 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1490         }
1491
1492         return ret;
1493 }
1494
1495 #ifdef CONFIG_IPV6_SIT_6RD
1496 /* This function returns true when 6RD attributes are present in the nl msg */
1497 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1498                                     struct ip_tunnel_6rd *ip6rd)
1499 {
1500         bool ret = false;
1501         memset(ip6rd, 0, sizeof(*ip6rd));
1502
1503         if (!data)
1504                 return ret;
1505
1506         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1507                 ret = true;
1508                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1509         }
1510
1511         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1512                 ret = true;
1513                 ip6rd->relay_prefix =
1514                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1515         }
1516
1517         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1518                 ret = true;
1519                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1520         }
1521
1522         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1523                 ret = true;
1524                 ip6rd->relay_prefixlen =
1525                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1526         }
1527
1528         return ret;
1529 }
1530 #endif
1531
1532 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1533                          struct nlattr *tb[], struct nlattr *data[])
1534 {
1535         struct net *net = dev_net(dev);
1536         struct ip_tunnel *nt;
1537         struct ip_tunnel_encap ipencap;
1538 #ifdef CONFIG_IPV6_SIT_6RD
1539         struct ip_tunnel_6rd ip6rd;
1540 #endif
1541         int err;
1542
1543         nt = netdev_priv(dev);
1544
1545         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1546                 err = ip_tunnel_encap_setup(nt, &ipencap);
1547                 if (err < 0)
1548                         return err;
1549         }
1550
1551         ipip6_netlink_parms(data, &nt->parms);
1552
1553         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1554                 return -EEXIST;
1555
1556         err = ipip6_tunnel_create(dev);
1557         if (err < 0)
1558                 return err;
1559
1560 #ifdef CONFIG_IPV6_SIT_6RD
1561         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1562                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1563 #endif
1564
1565         return err;
1566 }
1567
1568 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1569                           struct nlattr *data[])
1570 {
1571         struct ip_tunnel *t = netdev_priv(dev);
1572         struct ip_tunnel_parm p;
1573         struct ip_tunnel_encap ipencap;
1574         struct net *net = t->net;
1575         struct sit_net *sitn = net_generic(net, sit_net_id);
1576 #ifdef CONFIG_IPV6_SIT_6RD
1577         struct ip_tunnel_6rd ip6rd;
1578 #endif
1579         int err;
1580
1581         if (dev == sitn->fb_tunnel_dev)
1582                 return -EINVAL;
1583
1584         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1585                 err = ip_tunnel_encap_setup(t, &ipencap);
1586                 if (err < 0)
1587                         return err;
1588         }
1589
1590         ipip6_netlink_parms(data, &p);
1591
1592         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1593             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1594                 return -EINVAL;
1595
1596         t = ipip6_tunnel_locate(net, &p, 0);
1597
1598         if (t) {
1599                 if (t->dev != dev)
1600                         return -EEXIST;
1601         } else
1602                 t = netdev_priv(dev);
1603
1604         ipip6_tunnel_update(t, &p);
1605
1606 #ifdef CONFIG_IPV6_SIT_6RD
1607         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1608                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1609 #endif
1610
1611         return 0;
1612 }
1613
1614 static size_t ipip6_get_size(const struct net_device *dev)
1615 {
1616         return
1617                 /* IFLA_IPTUN_LINK */
1618                 nla_total_size(4) +
1619                 /* IFLA_IPTUN_LOCAL */
1620                 nla_total_size(4) +
1621                 /* IFLA_IPTUN_REMOTE */
1622                 nla_total_size(4) +
1623                 /* IFLA_IPTUN_TTL */
1624                 nla_total_size(1) +
1625                 /* IFLA_IPTUN_TOS */
1626                 nla_total_size(1) +
1627                 /* IFLA_IPTUN_PMTUDISC */
1628                 nla_total_size(1) +
1629                 /* IFLA_IPTUN_FLAGS */
1630                 nla_total_size(2) +
1631                 /* IFLA_IPTUN_PROTO */
1632                 nla_total_size(1) +
1633 #ifdef CONFIG_IPV6_SIT_6RD
1634                 /* IFLA_IPTUN_6RD_PREFIX */
1635                 nla_total_size(sizeof(struct in6_addr)) +
1636                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1637                 nla_total_size(4) +
1638                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1639                 nla_total_size(2) +
1640                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1641                 nla_total_size(2) +
1642 #endif
1643                 /* IFLA_IPTUN_ENCAP_TYPE */
1644                 nla_total_size(2) +
1645                 /* IFLA_IPTUN_ENCAP_FLAGS */
1646                 nla_total_size(2) +
1647                 /* IFLA_IPTUN_ENCAP_SPORT */
1648                 nla_total_size(2) +
1649                 /* IFLA_IPTUN_ENCAP_DPORT */
1650                 nla_total_size(2) +
1651                 0;
1652 }
1653
1654 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1655 {
1656         struct ip_tunnel *tunnel = netdev_priv(dev);
1657         struct ip_tunnel_parm *parm = &tunnel->parms;
1658
1659         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1660             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1661             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1662             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1663             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1664             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1665                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1666             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1667             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1668                 goto nla_put_failure;
1669
1670 #ifdef CONFIG_IPV6_SIT_6RD
1671         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1672                              &tunnel->ip6rd.prefix) ||
1673             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1674                             tunnel->ip6rd.relay_prefix) ||
1675             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1676                         tunnel->ip6rd.prefixlen) ||
1677             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1678                         tunnel->ip6rd.relay_prefixlen))
1679                 goto nla_put_failure;
1680 #endif
1681
1682         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1683                         tunnel->encap.type) ||
1684             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1685                         tunnel->encap.sport) ||
1686             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1687                         tunnel->encap.dport) ||
1688             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1689                         tunnel->encap.flags))
1690                 goto nla_put_failure;
1691
1692         return 0;
1693
1694 nla_put_failure:
1695         return -EMSGSIZE;
1696 }
1697
1698 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1699         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1700         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1701         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1702         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1703         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1704         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1705         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1706         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1707 #ifdef CONFIG_IPV6_SIT_6RD
1708         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1709         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1710         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1711         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1712 #endif
1713         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1714         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1715         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1716         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1717 };
1718
1719 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1720 {
1721         struct net *net = dev_net(dev);
1722         struct sit_net *sitn = net_generic(net, sit_net_id);
1723
1724         if (dev != sitn->fb_tunnel_dev)
1725                 unregister_netdevice_queue(dev, head);
1726 }
1727
1728 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1729         .kind           = "sit",
1730         .maxtype        = IFLA_IPTUN_MAX,
1731         .policy         = ipip6_policy,
1732         .priv_size      = sizeof(struct ip_tunnel),
1733         .setup          = ipip6_tunnel_setup,
1734         .validate       = ipip6_validate,
1735         .newlink        = ipip6_newlink,
1736         .changelink     = ipip6_changelink,
1737         .get_size       = ipip6_get_size,
1738         .fill_info      = ipip6_fill_info,
1739         .dellink        = ipip6_dellink,
1740         .get_link_net   = ip_tunnel_get_link_net,
1741 };
1742
1743 static struct xfrm_tunnel sit_handler __read_mostly = {
1744         .handler        =       ipip6_rcv,
1745         .err_handler    =       ipip6_err,
1746         .priority       =       1,
1747 };
1748
1749 static struct xfrm_tunnel ipip_handler __read_mostly = {
1750         .handler        =       ipip_rcv,
1751         .err_handler    =       ipip6_err,
1752         .priority       =       2,
1753 };
1754
1755 #if IS_ENABLED(CONFIG_MPLS)
1756 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1757         .handler        =       mplsip_rcv,
1758         .err_handler    =       ipip6_err,
1759         .priority       =       2,
1760 };
1761 #endif
1762
1763 static void __net_exit sit_destroy_tunnels(struct net *net,
1764                                            struct list_head *head)
1765 {
1766         struct sit_net *sitn = net_generic(net, sit_net_id);
1767         struct net_device *dev, *aux;
1768         int prio;
1769
1770         for_each_netdev_safe(net, dev, aux)
1771                 if (dev->rtnl_link_ops == &sit_link_ops)
1772                         unregister_netdevice_queue(dev, head);
1773
1774         for (prio = 1; prio < 4; prio++) {
1775                 int h;
1776                 for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1777                         struct ip_tunnel *t;
1778
1779                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1780                         while (t) {
1781                                 /* If dev is in the same netns, it has already
1782                                  * been added to the list by the previous loop.
1783                                  */
1784                                 if (!net_eq(dev_net(t->dev), net))
1785                                         unregister_netdevice_queue(t->dev,
1786                                                                    head);
1787                                 t = rtnl_dereference(t->next);
1788                         }
1789                 }
1790         }
1791 }
1792
1793 static int __net_init sit_init_net(struct net *net)
1794 {
1795         struct sit_net *sitn = net_generic(net, sit_net_id);
1796         struct ip_tunnel *t;
1797         int err;
1798
1799         sitn->tunnels[0] = sitn->tunnels_wc;
1800         sitn->tunnels[1] = sitn->tunnels_l;
1801         sitn->tunnels[2] = sitn->tunnels_r;
1802         sitn->tunnels[3] = sitn->tunnels_r_l;
1803
1804         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1805                                            NET_NAME_UNKNOWN,
1806                                            ipip6_tunnel_setup);
1807         if (!sitn->fb_tunnel_dev) {
1808                 err = -ENOMEM;
1809                 goto err_alloc_dev;
1810         }
1811         dev_net_set(sitn->fb_tunnel_dev, net);
1812         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1813         /* FB netdevice is special: we have one, and only one per netns.
1814          * Allowing to move it to another netns is clearly unsafe.
1815          */
1816         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1817
1818         err = register_netdev(sitn->fb_tunnel_dev);
1819         if (err)
1820                 goto err_reg_dev;
1821
1822         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1823         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1824
1825         t = netdev_priv(sitn->fb_tunnel_dev);
1826
1827         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1828         return 0;
1829
1830 err_reg_dev:
1831         ipip6_dev_free(sitn->fb_tunnel_dev);
1832 err_alloc_dev:
1833         return err;
1834 }
1835
1836 static void __net_exit sit_exit_net(struct net *net)
1837 {
1838         LIST_HEAD(list);
1839
1840         rtnl_lock();
1841         sit_destroy_tunnels(net, &list);
1842         unregister_netdevice_many(&list);
1843         rtnl_unlock();
1844 }
1845
1846 static struct pernet_operations sit_net_ops = {
1847         .init = sit_init_net,
1848         .exit = sit_exit_net,
1849         .id   = &sit_net_id,
1850         .size = sizeof(struct sit_net),
1851 };
1852
1853 static void __exit sit_cleanup(void)
1854 {
1855         rtnl_link_unregister(&sit_link_ops);
1856         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1857         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1858 #if IS_ENABLED(CONFIG_MPLS)
1859         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1860 #endif
1861
1862         unregister_pernet_device(&sit_net_ops);
1863         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1864 }
1865
1866 static int __init sit_init(void)
1867 {
1868         int err;
1869
1870         pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1871
1872         err = register_pernet_device(&sit_net_ops);
1873         if (err < 0)
1874                 return err;
1875         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1876         if (err < 0) {
1877                 pr_info("%s: can't register ip6ip4\n", __func__);
1878                 goto xfrm_tunnel_failed;
1879         }
1880         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1881         if (err < 0) {
1882                 pr_info("%s: can't register ip4ip4\n", __func__);
1883                 goto xfrm_tunnel4_failed;
1884         }
1885 #if IS_ENABLED(CONFIG_MPLS)
1886         err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1887         if (err < 0) {
1888                 pr_info("%s: can't register mplsip\n", __func__);
1889                 goto xfrm_tunnel_mpls_failed;
1890         }
1891 #endif
1892         err = rtnl_link_register(&sit_link_ops);
1893         if (err < 0)
1894                 goto rtnl_link_failed;
1895
1896 out:
1897         return err;
1898
1899 rtnl_link_failed:
1900 #if IS_ENABLED(CONFIG_MPLS)
1901         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1902 xfrm_tunnel_mpls_failed:
1903 #endif
1904         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1905 xfrm_tunnel4_failed:
1906         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1907 xfrm_tunnel_failed:
1908         unregister_pernet_device(&sit_net_ops);
1909         goto out;
1910 }
1911
1912 module_init(sit_init);
1913 module_exit(sit_cleanup);
1914 MODULE_LICENSE("GPL");
1915 MODULE_ALIAS_RTNL_LINK("sit");
1916 MODULE_ALIAS_NETDEV("sit0");