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 (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         ipip6_tunnel_link(sitn, t);
 213         return 0;
 214
 215 out:
 216         return err;
 217 }
 218
 219 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 220                 struct ip_tunnel_parm *parms, int create)
 221 {
 222         __be32 remote = parms->iph.daddr;
 223         __be32 local = parms->iph.saddr;
 224         struct ip_tunnel *t, *nt;
 225         struct ip_tunnel __rcu **tp;
 226         struct net_device *dev;
 227         char name[IFNAMSIZ];
 228         struct sit_net *sitn = net_generic(net, sit_net_id);
 229
 230         for (tp = __ipip6_bucket(sitn, parms);
 231             (t = rtnl_dereference(*tp)) != NULL;
 232              tp = &t->next) {
 233                 if (local == t->parms.iph.saddr &&
 234                     remote == t->parms.iph.daddr &&
 235                     parms->link == t->parms.link) {
 236                         if (create)
 237                                 return NULL;
 238                         else
 239                                 return t;
 240                 }
 241         }
 242         if (!create)
 243                 goto failed;
 244
 245         if (parms->name[0]) {
 246                 if (!dev_valid_name(parms->name))
 247                         goto failed;
 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         free_netdev(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 | __GFP_NOWARN) :
 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 (__in6_dev_get(skb->dev) &&
 542             !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 543                 goto out;
 544
 545         if (t->parms.iph.daddr == 0)
 546                 goto out;
 547
 548         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 549                 goto out;
 550
 551         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 552                 t->err_count++;
 553         else
 554                 t->err_count = 1;
 555         t->err_time = jiffies;
 556 out:
 557         return err;
 558 }
 559
 560 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 561                                   const struct in6_addr *v6addr)
 562 {
 563         __be32 v4embed = 0;
 564         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 565                 return true;
 566         return false;
 567 }
 568
 569 /* Checks if an address matches an address on the tunnel interface.
 570  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 571  * Long story:
 572  * This function is called after we considered the packet as spoofed
 573  * in is_spoofed_6rd.
 574  * We may have a router that is doing NAT for proto 41 packets
 575  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 576  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 577  * function will return true, dropping the packet.
 578  * But, we can still check if is spoofed against the IP
 579  * addresses associated with the interface.
 580  */
 581 static bool only_dnatted(const struct ip_tunnel *tunnel,
 582         const struct in6_addr *v6dst)
 583 {
 584         int prefix_len;
 585
 586 #ifdef CONFIG_IPV6_SIT_6RD
 587         prefix_len = tunnel->ip6rd.prefixlen + 32
 588                 - tunnel->ip6rd.relay_prefixlen;
 589 #else
 590         prefix_len = 48;
 591 #endif
 592         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 593 }
 594
 595 /* Returns true if a packet is spoofed */
 596 static bool packet_is_spoofed(struct sk_buff *skb,
 597                               const struct iphdr *iph,
 598                               struct ip_tunnel *tunnel)
 599 {
 600         const struct ipv6hdr *ipv6h;
 601
 602         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 603                 if (!isatap_chksrc(skb, iph, tunnel))
 604                         return true;
 605
 606                 return false;
 607         }
 608
 609         if (tunnel->dev->flags & IFF_POINTOPOINT)
 610                 return false;
 611
 612         ipv6h = ipv6_hdr(skb);
 613
 614         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 615                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 616                                      &iph->saddr, &ipv6h->saddr,
 617                                      &iph->daddr, &ipv6h->daddr);
 618                 return true;
 619         }
 620
 621         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 622                 return false;
 623
 624         if (only_dnatted(tunnel, &ipv6h->daddr))
 625                 return false;
 626
 627         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 628                              &iph->saddr, &ipv6h->saddr,
 629                              &iph->daddr, &ipv6h->daddr);
 630         return true;
 631 }
 632
 633 static int ipip6_rcv(struct sk_buff *skb)
 634 {
 635         const struct iphdr *iph = ip_hdr(skb);
 636         struct ip_tunnel *tunnel;
 637         int err;
 638
 639         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 640                                      iph->saddr, iph->daddr);
 641         if (tunnel) {
 642                 struct pcpu_sw_netstats *tstats;
 643
 644                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 645                     tunnel->parms.iph.protocol != 0)
 646                         goto out;
 647
 648                 skb->mac_header = skb->network_header;
 649                 skb_reset_network_header(skb);
 650                 IPCB(skb)->flags = 0;
 651                 skb->dev = tunnel->dev;
 652
 653                 if (packet_is_spoofed(skb, iph, tunnel)) {
 654                         tunnel->dev->stats.rx_errors++;
 655                         goto out;
 656                 }
 657
 658                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 659                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
 660                         goto out;
 661
 662                 /* skb can be uncloned in iptunnel_pull_header, so
 663                  * old iph is no longer valid
 664                  */
 665                 iph = (const struct iphdr *)skb_mac_header(skb);
 666                 err = IP_ECN_decapsulate(iph, skb);
 667                 if (unlikely(err)) {
 668                         if (log_ecn_error)
 669                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 670                                                      &iph->saddr, iph->tos);
 671                         if (err > 1) {
 672                                 ++tunnel->dev->stats.rx_frame_errors;
 673                                 ++tunnel->dev->stats.rx_errors;
 674                                 goto out;
 675                         }
 676                 }
 677
 678                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 679                 u64_stats_update_begin(&tstats->syncp);
 680                 tstats->rx_packets++;
 681                 tstats->rx_bytes += skb->len;
 682                 u64_stats_update_end(&tstats->syncp);
 683
 684                 netif_rx(skb);
 685
 686                 return 0;
 687         }
 688
 689         /* no tunnel matched,  let upstream know, ipsec may handle it */
 690         return 1;
 691 out:
 692         kfree_skb(skb);
 693         return 0;
 694 }
 695
 696 static const struct tnl_ptk_info ipip_tpi = {
 697         /* no tunnel info required for ipip. */
 698         .proto = htons(ETH_P_IP),
 699 };
 700
 701 #if IS_ENABLED(CONFIG_MPLS)
 702 static const struct tnl_ptk_info mplsip_tpi = {
 703         /* no tunnel info required for mplsip. */
 704         .proto = htons(ETH_P_MPLS_UC),
 705 };
 706 #endif
 707
 708 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 709 {
 710         const struct iphdr *iph;
 711         struct ip_tunnel *tunnel;
 712
 713         iph = ip_hdr(skb);
 714         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 715                                      iph->saddr, iph->daddr);
 716         if (tunnel) {
 717                 const struct tnl_ptk_info *tpi;
 718
 719                 if (tunnel->parms.iph.protocol != ipproto &&
 720                     tunnel->parms.iph.protocol != 0)
 721                         goto drop;
 722
 723                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 724                         goto drop;
 725 #if IS_ENABLED(CONFIG_MPLS)
 726                 if (ipproto == IPPROTO_MPLS)
 727                         tpi = &mplsip_tpi;
 728                 else
 729 #endif
 730                         tpi = &ipip_tpi;
 731                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
 732                         goto drop;
 733                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 734         }
 735
 736         return 1;
 737
 738 drop:
 739         kfree_skb(skb);
 740         return 0;
 741 }
 742
 743 static int ipip_rcv(struct sk_buff *skb)
 744 {
 745         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
 746 }
 747
 748 #if IS_ENABLED(CONFIG_MPLS)
 749 static int mplsip_rcv(struct sk_buff *skb)
 750 {
 751         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
 752 }
 753 #endif
 754
 755 /*
 756  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 757  * stores the embedded IPv4 address in v4dst and returns true.
 758  */
 759 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 760                       __be32 *v4dst)
 761 {
 762 #ifdef CONFIG_IPV6_SIT_6RD
 763         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 764                               tunnel->ip6rd.prefixlen)) {
 765                 unsigned int pbw0, pbi0;
 766                 int pbi1;
 767                 u32 d;
 768
 769                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 770                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 771
 772                 d = tunnel->ip6rd.relay_prefixlen < 32 ?
 773                         (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 774                     tunnel->ip6rd.relay_prefixlen : 0;
 775
 776                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 777                 if (pbi1 > 0)
 778                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 779                              (32 - pbi1);
 780
 781                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 782                 return true;
 783         }
 784 #else
 785         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 786                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 787                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 788                 return true;
 789         }
 790 #endif
 791         return false;
 792 }
 793
 794 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 795                              const struct in6_addr *v6dst)
 796 {
 797         __be32 dst = 0;
 798         check_6rd(tunnel, v6dst, &dst);
 799         return dst;
 800 }
 801
 802 /*
 803  *      This function assumes it is being called from dev_queue_xmit()
 804  *      and that skb is filled properly by that function.
 805  */
 806
 807 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 808                                      struct net_device *dev)
 809 {
 810         struct ip_tunnel *tunnel = netdev_priv(dev);
 811         const struct iphdr  *tiph = &tunnel->parms.iph;
 812         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 813         u8     tos = tunnel->parms.iph.tos;
 814         __be16 df = tiph->frag_off;
 815         struct rtable *rt;              /* Route to the other host */
 816         struct net_device *tdev;        /* Device to other host */
 817         unsigned int max_headroom;      /* The extra header space needed */
 818         __be32 dst = tiph->daddr;
 819         struct flowi4 fl4;
 820         int    mtu;
 821         const struct in6_addr *addr6;
 822         int addr_type;
 823         u8 ttl;
 824         u8 protocol = IPPROTO_IPV6;
 825         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 826
 827         if (tos == 1)
 828                 tos = ipv6_get_dsfield(iph6);
 829
 830         /* ISATAP (RFC4214) - must come before 6to4 */
 831         if (dev->priv_flags & IFF_ISATAP) {
 832                 struct neighbour *neigh = NULL;
 833                 bool do_tx_error = false;
 834
 835                 if (skb_dst(skb))
 836                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 837
 838                 if (!neigh) {
 839                         net_dbg_ratelimited("nexthop == NULL\n");
 840                         goto tx_error;
 841                 }
 842
 843                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 844                 addr_type = ipv6_addr_type(addr6);
 845
 846                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 847                      ipv6_addr_is_isatap(addr6))
 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         if (!dst)
 858                 dst = try_6rd(tunnel, &iph6->daddr);
 859
 860         if (!dst) {
 861                 struct neighbour *neigh = NULL;
 862                 bool do_tx_error = false;
 863
 864                 if (skb_dst(skb))
 865                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 866
 867                 if (!neigh) {
 868                         net_dbg_ratelimited("nexthop == NULL\n");
 869                         goto tx_error;
 870                 }
 871
 872                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 873                 addr_type = ipv6_addr_type(addr6);
 874
 875                 if (addr_type == IPV6_ADDR_ANY) {
 876                         addr6 = &ipv6_hdr(skb)->daddr;
 877                         addr_type = ipv6_addr_type(addr6);
 878                 }
 879
 880                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 881                         dst = addr6->s6_addr32[3];
 882                 else
 883                         do_tx_error = true;
 884
 885                 neigh_release(neigh);
 886                 if (do_tx_error)
 887                         goto tx_error;
 888         }
 889
 890         flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
 891                            RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
 892                            0, dst, tiph->saddr, 0, 0,
 893                            sock_net_uid(tunnel->net, NULL));
 894         rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
 895
 896         if (IS_ERR(rt)) {
 897                 dev->stats.tx_carrier_errors++;
 898                 goto tx_error_icmp;
 899         }
 900         if (rt->rt_type != RTN_UNICAST) {
 901                 ip_rt_put(rt);
 902                 dev->stats.tx_carrier_errors++;
 903                 goto tx_error_icmp;
 904         }
 905         tdev = rt->dst.dev;
 906
 907         if (tdev == dev) {
 908                 ip_rt_put(rt);
 909                 dev->stats.collisions++;
 910                 goto tx_error;
 911         }
 912
 913         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 914                 ip_rt_put(rt);
 915                 goto tx_error;
 916         }
 917
 918         if (df) {
 919                 mtu = dst_mtu(&rt->dst) - t_hlen;
 920
 921                 if (mtu < 68) {
 922                         dev->stats.collisions++;
 923                         ip_rt_put(rt);
 924                         goto tx_error;
 925                 }
 926
 927                 if (mtu < IPV6_MIN_MTU) {
 928                         mtu = IPV6_MIN_MTU;
 929                         df = 0;
 930                 }
 931
 932                 if (tunnel->parms.iph.daddr)
 933                         skb_dst_update_pmtu_no_confirm(skb, mtu);
 934
 935                 if (skb->len > mtu && !skb_is_gso(skb)) {
 936                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 937                         ip_rt_put(rt);
 938                         goto tx_error;
 939                 }
 940         }
 941
 942         if (tunnel->err_count > 0) {
 943                 if (time_before(jiffies,
 944                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 945                         tunnel->err_count--;
 946                         dst_link_failure(skb);
 947                 } else
 948                         tunnel->err_count = 0;
 949         }
 950
 951         /*
 952          * Okay, now see if we can stuff it in the buffer as-is.
 953          */
 954         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 955
 956         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 957             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 958                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 959                 if (!new_skb) {
 960                         ip_rt_put(rt);
 961                         dev->stats.tx_dropped++;
 962                         kfree_skb(skb);
 963                         return NETDEV_TX_OK;
 964                 }
 965                 if (skb->sk)
 966                         skb_set_owner_w(new_skb, skb->sk);
 967                 dev_kfree_skb(skb);
 968                 skb = new_skb;
 969                 iph6 = ipv6_hdr(skb);
 970         }
 971         ttl = tiph->ttl;
 972         if (ttl == 0)
 973                 ttl = iph6->hop_limit;
 974         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 975
 976         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 977                 ip_rt_put(rt);
 978                 goto tx_error;
 979         }
 980
 981         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 982
 983         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 984                       df, !net_eq(tunnel->net, dev_net(dev)));
 985         return NETDEV_TX_OK;
 986
 987 tx_error_icmp:
 988         dst_link_failure(skb);
 989 tx_error:
 990         kfree_skb(skb);
 991         dev->stats.tx_errors++;
 992         return NETDEV_TX_OK;
 993 }
 994
 995 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
 996                                      struct net_device *dev, u8 ipproto)
 997 {
 998         struct ip_tunnel *tunnel = netdev_priv(dev);
 999         const struct iphdr  *tiph = &tunnel->parms.iph;
1000
1001         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1002                 goto tx_error;
1003
1004         skb_set_inner_ipproto(skb, ipproto);
1005
1006         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1007         return NETDEV_TX_OK;
1008 tx_error:
1009         kfree_skb(skb);
1010         dev->stats.tx_errors++;
1011         return NETDEV_TX_OK;
1012 }
1013
1014 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1015                                    struct net_device *dev)
1016 {
1017         switch (skb->protocol) {
1018         case htons(ETH_P_IP):
1019                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1020                 break;
1021         case htons(ETH_P_IPV6):
1022                 ipip6_tunnel_xmit(skb, dev);
1023                 break;
1024 #if IS_ENABLED(CONFIG_MPLS)
1025         case htons(ETH_P_MPLS_UC):
1026                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1027                 break;
1028 #endif
1029         default:
1030                 goto tx_err;
1031         }
1032
1033         return NETDEV_TX_OK;
1034
1035 tx_err:
1036         dev->stats.tx_errors++;
1037         kfree_skb(skb);
1038         return NETDEV_TX_OK;
1039
1040 }
1041
1042 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1043 {
1044         struct net_device *tdev = NULL;
1045         struct ip_tunnel *tunnel;
1046         const struct iphdr *iph;
1047         struct flowi4 fl4;
1048
1049         tunnel = netdev_priv(dev);
1050         iph = &tunnel->parms.iph;
1051
1052         if (iph->daddr) {
1053                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1054                                                           NULL,
1055                                                           iph->daddr, iph->saddr,
1056                                                           0, 0,
1057                                                           IPPROTO_IPV6,
1058                                                           RT_TOS(iph->tos),
1059                                                           tunnel->parms.link);
1060
1061                 if (!IS_ERR(rt)) {
1062                         tdev = rt->dst.dev;
1063                         ip_rt_put(rt);
1064                 }
1065                 dev->flags |= IFF_POINTOPOINT;
1066         }
1067
1068         if (!tdev && tunnel->parms.link)
1069                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1070
1071         if (tdev && !netif_is_l3_master(tdev)) {
1072                 int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1073
1074                 dev->mtu = tdev->mtu - t_hlen;
1075                 if (dev->mtu < IPV6_MIN_MTU)
1076                         dev->mtu = IPV6_MIN_MTU;
1077         }
1078 }
1079
1080 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1081                                 __u32 fwmark)
1082 {
1083         struct net *net = t->net;
1084         struct sit_net *sitn = net_generic(net, sit_net_id);
1085
1086         ipip6_tunnel_unlink(sitn, t);
1087         synchronize_net();
1088         t->parms.iph.saddr = p->iph.saddr;
1089         t->parms.iph.daddr = p->iph.daddr;
1090         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1091         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1092         ipip6_tunnel_link(sitn, t);
1093         t->parms.iph.ttl = p->iph.ttl;
1094         t->parms.iph.tos = p->iph.tos;
1095         t->parms.iph.frag_off = p->iph.frag_off;
1096         if (t->parms.link != p->link || t->fwmark != fwmark) {
1097                 t->parms.link = p->link;
1098                 t->fwmark = fwmark;
1099                 ipip6_tunnel_bind_dev(t->dev);
1100         }
1101         dst_cache_reset(&t->dst_cache);
1102         netdev_state_change(t->dev);
1103 }
1104
1105 #ifdef CONFIG_IPV6_SIT_6RD
1106 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1107                                    struct ip_tunnel_6rd *ip6rd)
1108 {
1109         struct in6_addr prefix;
1110         __be32 relay_prefix;
1111
1112         if (ip6rd->relay_prefixlen > 32 ||
1113             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1114                 return -EINVAL;
1115
1116         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1117         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1118                 return -EINVAL;
1119         if (ip6rd->relay_prefixlen)
1120                 relay_prefix = ip6rd->relay_prefix &
1121                                htonl(0xffffffffUL <<
1122                                      (32 - ip6rd->relay_prefixlen));
1123         else
1124                 relay_prefix = 0;
1125         if (relay_prefix != ip6rd->relay_prefix)
1126                 return -EINVAL;
1127
1128         t->ip6rd.prefix = prefix;
1129         t->ip6rd.relay_prefix = relay_prefix;
1130         t->ip6rd.prefixlen = ip6rd->prefixlen;
1131         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1132         dst_cache_reset(&t->dst_cache);
1133         netdev_state_change(t->dev);
1134         return 0;
1135 }
1136 #endif
1137
1138 static bool ipip6_valid_ip_proto(u8 ipproto)
1139 {
1140         return ipproto == IPPROTO_IPV6 ||
1141                 ipproto == IPPROTO_IPIP ||
1142 #if IS_ENABLED(CONFIG_MPLS)
1143                 ipproto == IPPROTO_MPLS ||
1144 #endif
1145                 ipproto == 0;
1146 }
1147
1148 static int
1149 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1150 {
1151         int err = 0;
1152         struct ip_tunnel_parm p;
1153         struct ip_tunnel_prl prl;
1154         struct ip_tunnel *t = netdev_priv(dev);
1155         struct net *net = t->net;
1156         struct sit_net *sitn = net_generic(net, sit_net_id);
1157 #ifdef CONFIG_IPV6_SIT_6RD
1158         struct ip_tunnel_6rd ip6rd;
1159 #endif
1160
1161         switch (cmd) {
1162         case SIOCGETTUNNEL:
1163 #ifdef CONFIG_IPV6_SIT_6RD
1164         case SIOCGET6RD:
1165 #endif
1166                 if (dev == sitn->fb_tunnel_dev) {
1167                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1168                                 err = -EFAULT;
1169                                 break;
1170                         }
1171                         t = ipip6_tunnel_locate(net, &p, 0);
1172                         if (!t)
1173                                 t = netdev_priv(dev);
1174                 }
1175
1176                 err = -EFAULT;
1177                 if (cmd == SIOCGETTUNNEL) {
1178                         memcpy(&p, &t->parms, sizeof(p));
1179                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1180                                          sizeof(p)))
1181                                 goto done;
1182 #ifdef CONFIG_IPV6_SIT_6RD
1183                 } else {
1184                         ip6rd.prefix = t->ip6rd.prefix;
1185                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1186                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1187                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1188                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1189                                          sizeof(ip6rd)))
1190                                 goto done;
1191 #endif
1192                 }
1193                 err = 0;
1194                 break;
1195
1196         case SIOCADDTUNNEL:
1197         case SIOCCHGTUNNEL:
1198                 err = -EPERM;
1199                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1200                         goto done;
1201
1202                 err = -EFAULT;
1203                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1204                         goto done;
1205
1206                 err = -EINVAL;
1207                 if (!ipip6_valid_ip_proto(p.iph.protocol))
1208                         goto done;
1209                 if (p.iph.version != 4 ||
1210                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1211                         goto done;
1212                 if (p.iph.ttl)
1213                         p.iph.frag_off |= htons(IP_DF);
1214
1215                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1216
1217                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1218                         if (t) {
1219                                 if (t->dev != dev) {
1220                                         err = -EEXIST;
1221                                         break;
1222                                 }
1223                         } else {
1224                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1225                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1226                                         err = -EINVAL;
1227                                         break;
1228                                 }
1229                                 t = netdev_priv(dev);
1230                         }
1231
1232                         ipip6_tunnel_update(t, &p, t->fwmark);
1233                 }
1234
1235                 if (t) {
1236                         err = 0;
1237                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1238                                 err = -EFAULT;
1239                 } else
1240                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1241                 break;
1242
1243         case SIOCDELTUNNEL:
1244                 err = -EPERM;
1245                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1246                         goto done;
1247
1248                 if (dev == sitn->fb_tunnel_dev) {
1249                         err = -EFAULT;
1250                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1251                                 goto done;
1252                         err = -ENOENT;
1253                         t = ipip6_tunnel_locate(net, &p, 0);
1254                         if (!t)
1255                                 goto done;
1256                         err = -EPERM;
1257                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1258                                 goto done;
1259                         dev = t->dev;
1260                 }
1261                 unregister_netdevice(dev);
1262                 err = 0;
1263                 break;
1264
1265         case SIOCGETPRL:
1266                 err = -EINVAL;
1267                 if (dev == sitn->fb_tunnel_dev)
1268                         goto done;
1269                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1270                 break;
1271
1272         case SIOCADDPRL:
1273         case SIOCDELPRL:
1274         case SIOCCHGPRL:
1275                 err = -EPERM;
1276                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1277                         goto done;
1278                 err = -EINVAL;
1279                 if (dev == sitn->fb_tunnel_dev)
1280                         goto done;
1281                 err = -EFAULT;
1282                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1283                         goto done;
1284
1285                 switch (cmd) {
1286                 case SIOCDELPRL:
1287                         err = ipip6_tunnel_del_prl(t, &prl);
1288                         break;
1289                 case SIOCADDPRL:
1290                 case SIOCCHGPRL:
1291                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1292                         break;
1293                 }
1294                 dst_cache_reset(&t->dst_cache);
1295                 netdev_state_change(dev);
1296                 break;
1297
1298 #ifdef CONFIG_IPV6_SIT_6RD
1299         case SIOCADD6RD:
1300         case SIOCCHG6RD:
1301         case SIOCDEL6RD:
1302                 err = -EPERM;
1303                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1304                         goto done;
1305
1306                 err = -EFAULT;
1307                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1308                                    sizeof(ip6rd)))
1309                         goto done;
1310
1311                 if (cmd != SIOCDEL6RD) {
1312                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1313                         if (err < 0)
1314                                 goto done;
1315                 } else
1316                         ipip6_tunnel_clone_6rd(dev, sitn);
1317
1318                 err = 0;
1319                 break;
1320 #endif
1321
1322         default:
1323                 err = -EINVAL;
1324         }
1325
1326 done:
1327         return err;
1328 }
1329
1330 static const struct net_device_ops ipip6_netdev_ops = {
1331         .ndo_init       = ipip6_tunnel_init,
1332         .ndo_uninit     = ipip6_tunnel_uninit,
1333         .ndo_start_xmit = sit_tunnel_xmit,
1334         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1335         .ndo_get_stats64 = ip_tunnel_get_stats64,
1336         .ndo_get_iflink = ip_tunnel_get_iflink,
1337 };
1338
1339 static void ipip6_dev_free(struct net_device *dev)
1340 {
1341         struct ip_tunnel *tunnel = netdev_priv(dev);
1342
1343         dst_cache_destroy(&tunnel->dst_cache);
1344         free_percpu(dev->tstats);
1345 }
1346
1347 #define SIT_FEATURES (NETIF_F_SG           | \
1348                       NETIF_F_FRAGLIST     | \
1349                       NETIF_F_HIGHDMA      | \
1350                       NETIF_F_GSO_SOFTWARE | \
1351                       NETIF_F_HW_CSUM)
1352
1353 static void ipip6_tunnel_setup(struct net_device *dev)
1354 {
1355         struct ip_tunnel *tunnel = netdev_priv(dev);
1356         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1357
1358         dev->netdev_ops         = &ipip6_netdev_ops;
1359         dev->needs_free_netdev  = true;
1360         dev->priv_destructor    = ipip6_dev_free;
1361
1362         dev->type               = ARPHRD_SIT;
1363         dev->mtu                = ETH_DATA_LEN - t_hlen;
1364         dev->min_mtu            = IPV6_MIN_MTU;
1365         dev->max_mtu            = IP6_MAX_MTU - t_hlen;
1366         dev->flags              = IFF_NOARP;
1367         netif_keep_dst(dev);
1368         dev->addr_len           = 4;
1369         dev->features           |= NETIF_F_LLTX;
1370         dev->features           |= SIT_FEATURES;
1371         dev->hw_features        |= SIT_FEATURES;
1372 }
1373
1374 static int ipip6_tunnel_init(struct net_device *dev)
1375 {
1376         struct ip_tunnel *tunnel = netdev_priv(dev);
1377         int err;
1378
1379         tunnel->dev = dev;
1380         tunnel->net = dev_net(dev);
1381         strcpy(tunnel->parms.name, dev->name);
1382
1383         ipip6_tunnel_bind_dev(dev);
1384         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1385         if (!dev->tstats)
1386                 return -ENOMEM;
1387
1388         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1389         if (err) {
1390                 free_percpu(dev->tstats);
1391                 dev->tstats = NULL;
1392                 return err;
1393         }
1394         dev_hold(dev);
1395         return 0;
1396 }
1397
1398 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1399 {
1400         struct ip_tunnel *tunnel = netdev_priv(dev);
1401         struct iphdr *iph = &tunnel->parms.iph;
1402         struct net *net = dev_net(dev);
1403         struct sit_net *sitn = net_generic(net, sit_net_id);
1404
1405         iph->version            = 4;
1406         iph->protocol           = IPPROTO_IPV6;
1407         iph->ihl                = 5;
1408         iph->ttl                = 64;
1409
1410         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1411 }
1412
1413 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1414                           struct netlink_ext_ack *extack)
1415 {
1416         u8 proto;
1417
1418         if (!data || !data[IFLA_IPTUN_PROTO])
1419                 return 0;
1420
1421         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1422         if (!ipip6_valid_ip_proto(proto))
1423                 return -EINVAL;
1424
1425         return 0;
1426 }
1427
1428 static void ipip6_netlink_parms(struct nlattr *data[],
1429                                 struct ip_tunnel_parm *parms,
1430                                 __u32 *fwmark)
1431 {
1432         memset(parms, 0, sizeof(*parms));
1433
1434         parms->iph.version = 4;
1435         parms->iph.protocol = IPPROTO_IPV6;
1436         parms->iph.ihl = 5;
1437         parms->iph.ttl = 64;
1438
1439         if (!data)
1440                 return;
1441
1442         if (data[IFLA_IPTUN_LINK])
1443                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1444
1445         if (data[IFLA_IPTUN_LOCAL])
1446                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1447
1448         if (data[IFLA_IPTUN_REMOTE])
1449                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1450
1451         if (data[IFLA_IPTUN_TTL]) {
1452                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1453                 if (parms->iph.ttl)
1454                         parms->iph.frag_off = htons(IP_DF);
1455         }
1456
1457         if (data[IFLA_IPTUN_TOS])
1458                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1459
1460         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1461                 parms->iph.frag_off = htons(IP_DF);
1462
1463         if (data[IFLA_IPTUN_FLAGS])
1464                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1465
1466         if (data[IFLA_IPTUN_PROTO])
1467                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1468
1469         if (data[IFLA_IPTUN_FWMARK])
1470                 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1471 }
1472
1473 /* This function returns true when ENCAP attributes are present in the nl msg */
1474 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1475                                       struct ip_tunnel_encap *ipencap)
1476 {
1477         bool ret = false;
1478
1479         memset(ipencap, 0, sizeof(*ipencap));
1480
1481         if (!data)
1482                 return ret;
1483
1484         if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1485                 ret = true;
1486                 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1487         }
1488
1489         if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1490                 ret = true;
1491                 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1492         }
1493
1494         if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1495                 ret = true;
1496                 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1497         }
1498
1499         if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1500                 ret = true;
1501                 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1502         }
1503
1504         return ret;
1505 }
1506
1507 #ifdef CONFIG_IPV6_SIT_6RD
1508 /* This function returns true when 6RD attributes are present in the nl msg */
1509 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1510                                     struct ip_tunnel_6rd *ip6rd)
1511 {
1512         bool ret = false;
1513         memset(ip6rd, 0, sizeof(*ip6rd));
1514
1515         if (!data)
1516                 return ret;
1517
1518         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1519                 ret = true;
1520                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1521         }
1522
1523         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1524                 ret = true;
1525                 ip6rd->relay_prefix =
1526                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1527         }
1528
1529         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1530                 ret = true;
1531                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1532         }
1533
1534         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1535                 ret = true;
1536                 ip6rd->relay_prefixlen =
1537                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1538         }
1539
1540         return ret;
1541 }
1542 #endif
1543
1544 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1545                          struct nlattr *tb[], struct nlattr *data[],
1546                          struct netlink_ext_ack *extack)
1547 {
1548         struct net *net = dev_net(dev);
1549         struct ip_tunnel *nt;
1550         struct ip_tunnel_encap ipencap;
1551 #ifdef CONFIG_IPV6_SIT_6RD
1552         struct ip_tunnel_6rd ip6rd;
1553 #endif
1554         int err;
1555
1556         nt = netdev_priv(dev);
1557
1558         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1559                 err = ip_tunnel_encap_setup(nt, &ipencap);
1560                 if (err < 0)
1561                         return err;
1562         }
1563
1564         ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1565
1566         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1567                 return -EEXIST;
1568
1569         err = ipip6_tunnel_create(dev);
1570         if (err < 0)
1571                 return err;
1572
1573         if (tb[IFLA_MTU]) {
1574                 u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1575
1576                 if (mtu >= IPV6_MIN_MTU &&
1577                     mtu <= IP6_MAX_MTU - dev->hard_header_len)
1578                         dev->mtu = mtu;
1579         }
1580
1581 #ifdef CONFIG_IPV6_SIT_6RD
1582         if (ipip6_netlink_6rd_parms(data, &ip6rd)) {
1583                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1584                 if (err < 0)
1585                         unregister_netdevice_queue(dev, NULL);
1586         }
1587 #endif
1588
1589         return err;
1590 }
1591
1592 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1593                             struct nlattr *data[],
1594                             struct netlink_ext_ack *extack)
1595 {
1596         struct ip_tunnel *t = netdev_priv(dev);
1597         struct ip_tunnel_parm p;
1598         struct ip_tunnel_encap ipencap;
1599         struct net *net = t->net;
1600         struct sit_net *sitn = net_generic(net, sit_net_id);
1601 #ifdef CONFIG_IPV6_SIT_6RD
1602         struct ip_tunnel_6rd ip6rd;
1603 #endif
1604         __u32 fwmark = t->fwmark;
1605         int err;
1606
1607         if (dev == sitn->fb_tunnel_dev)
1608                 return -EINVAL;
1609
1610         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1611                 err = ip_tunnel_encap_setup(t, &ipencap);
1612                 if (err < 0)
1613                         return err;
1614         }
1615
1616         ipip6_netlink_parms(data, &p, &fwmark);
1617
1618         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1619             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1620                 return -EINVAL;
1621
1622         t = ipip6_tunnel_locate(net, &p, 0);
1623
1624         if (t) {
1625                 if (t->dev != dev)
1626                         return -EEXIST;
1627         } else
1628                 t = netdev_priv(dev);
1629
1630         ipip6_tunnel_update(t, &p, fwmark);
1631
1632 #ifdef CONFIG_IPV6_SIT_6RD
1633         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1634                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1635 #endif
1636
1637         return 0;
1638 }
1639
1640 static size_t ipip6_get_size(const struct net_device *dev)
1641 {
1642         return
1643                 /* IFLA_IPTUN_LINK */
1644                 nla_total_size(4) +
1645                 /* IFLA_IPTUN_LOCAL */
1646                 nla_total_size(4) +
1647                 /* IFLA_IPTUN_REMOTE */
1648                 nla_total_size(4) +
1649                 /* IFLA_IPTUN_TTL */
1650                 nla_total_size(1) +
1651                 /* IFLA_IPTUN_TOS */
1652                 nla_total_size(1) +
1653                 /* IFLA_IPTUN_PMTUDISC */
1654                 nla_total_size(1) +
1655                 /* IFLA_IPTUN_FLAGS */
1656                 nla_total_size(2) +
1657                 /* IFLA_IPTUN_PROTO */
1658                 nla_total_size(1) +
1659 #ifdef CONFIG_IPV6_SIT_6RD
1660                 /* IFLA_IPTUN_6RD_PREFIX */
1661                 nla_total_size(sizeof(struct in6_addr)) +
1662                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1663                 nla_total_size(4) +
1664                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1665                 nla_total_size(2) +
1666                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1667                 nla_total_size(2) +
1668 #endif
1669                 /* IFLA_IPTUN_ENCAP_TYPE */
1670                 nla_total_size(2) +
1671                 /* IFLA_IPTUN_ENCAP_FLAGS */
1672                 nla_total_size(2) +
1673                 /* IFLA_IPTUN_ENCAP_SPORT */
1674                 nla_total_size(2) +
1675                 /* IFLA_IPTUN_ENCAP_DPORT */
1676                 nla_total_size(2) +
1677                 /* IFLA_IPTUN_FWMARK */
1678                 nla_total_size(4) +
1679                 0;
1680 }
1681
1682 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1683 {
1684         struct ip_tunnel *tunnel = netdev_priv(dev);
1685         struct ip_tunnel_parm *parm = &tunnel->parms;
1686
1687         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1688             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1689             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1690             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1691             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1692             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1693                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1694             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1695             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1696             nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1697                 goto nla_put_failure;
1698
1699 #ifdef CONFIG_IPV6_SIT_6RD
1700         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1701                              &tunnel->ip6rd.prefix) ||
1702             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1703                             tunnel->ip6rd.relay_prefix) ||
1704             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1705                         tunnel->ip6rd.prefixlen) ||
1706             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1707                         tunnel->ip6rd.relay_prefixlen))
1708                 goto nla_put_failure;
1709 #endif
1710
1711         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1712                         tunnel->encap.type) ||
1713             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1714                         tunnel->encap.sport) ||
1715             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1716                         tunnel->encap.dport) ||
1717             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1718                         tunnel->encap.flags))
1719                 goto nla_put_failure;
1720
1721         return 0;
1722
1723 nla_put_failure:
1724         return -EMSGSIZE;
1725 }
1726
1727 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1728         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1729         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1730         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1731         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1732         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1733         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1734         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1735         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1736 #ifdef CONFIG_IPV6_SIT_6RD
1737         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1738         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1739         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1740         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1741 #endif
1742         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1743         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1744         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1745         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1746         [IFLA_IPTUN_FWMARK]             = { .type = NLA_U32 },
1747 };
1748
1749 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1750 {
1751         struct net *net = dev_net(dev);
1752         struct sit_net *sitn = net_generic(net, sit_net_id);
1753
1754         if (dev != sitn->fb_tunnel_dev)
1755                 unregister_netdevice_queue(dev, head);
1756 }
1757
1758 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1759         .kind           = "sit",
1760         .maxtype        = IFLA_IPTUN_MAX,
1761         .policy         = ipip6_policy,
1762         .priv_size      = sizeof(struct ip_tunnel),
1763         .setup          = ipip6_tunnel_setup,
1764         .validate       = ipip6_validate,
1765         .newlink        = ipip6_newlink,
1766         .changelink     = ipip6_changelink,
1767         .get_size       = ipip6_get_size,
1768         .fill_info      = ipip6_fill_info,
1769         .dellink        = ipip6_dellink,
1770         .get_link_net   = ip_tunnel_get_link_net,
1771 };
1772
1773 static struct xfrm_tunnel sit_handler __read_mostly = {
1774         .handler        =       ipip6_rcv,
1775         .err_handler    =       ipip6_err,
1776         .priority       =       1,
1777 };
1778
1779 static struct xfrm_tunnel ipip_handler __read_mostly = {
1780         .handler        =       ipip_rcv,
1781         .err_handler    =       ipip6_err,
1782         .priority       =       2,
1783 };
1784
1785 #if IS_ENABLED(CONFIG_MPLS)
1786 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1787         .handler        =       mplsip_rcv,
1788         .err_handler    =       ipip6_err,
1789         .priority       =       2,
1790 };
1791 #endif
1792
1793 static void __net_exit sit_destroy_tunnels(struct net *net,
1794                                            struct list_head *head)
1795 {
1796         struct sit_net *sitn = net_generic(net, sit_net_id);
1797         struct net_device *dev, *aux;
1798         int prio;
1799
1800         for_each_netdev_safe(net, dev, aux)
1801                 if (dev->rtnl_link_ops == &sit_link_ops)
1802                         unregister_netdevice_queue(dev, head);
1803
1804         for (prio = 0; prio < 4; prio++) {
1805                 int h;
1806                 for (h = 0; h < (prio ? IP6_SIT_HASH_SIZE : 1); h++) {
1807                         struct ip_tunnel *t;
1808
1809                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1810                         while (t) {
1811                                 /* If dev is in the same netns, it has already
1812                                  * been added to the list by the previous loop.
1813                                  */
1814                                 if (!net_eq(dev_net(t->dev), net))
1815                                         unregister_netdevice_queue(t->dev,
1816                                                                    head);
1817                                 t = rtnl_dereference(t->next);
1818                         }
1819                 }
1820         }
1821 }
1822
1823 static int __net_init sit_init_net(struct net *net)
1824 {
1825         struct sit_net *sitn = net_generic(net, sit_net_id);
1826         struct ip_tunnel *t;
1827         int err;
1828
1829         sitn->tunnels[0] = sitn->tunnels_wc;
1830         sitn->tunnels[1] = sitn->tunnels_l;
1831         sitn->tunnels[2] = sitn->tunnels_r;
1832         sitn->tunnels[3] = sitn->tunnels_r_l;
1833
1834         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1835                                            NET_NAME_UNKNOWN,
1836                                            ipip6_tunnel_setup);
1837         if (!sitn->fb_tunnel_dev) {
1838                 err = -ENOMEM;
1839                 goto err_alloc_dev;
1840         }
1841         dev_net_set(sitn->fb_tunnel_dev, net);
1842         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1843         /* FB netdevice is special: we have one, and only one per netns.
1844          * Allowing to move it to another netns is clearly unsafe.
1845          */
1846         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1847
1848         err = register_netdev(sitn->fb_tunnel_dev);
1849         if (err)
1850                 goto err_reg_dev;
1851
1852         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1853         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1854
1855         t = netdev_priv(sitn->fb_tunnel_dev);
1856
1857         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1858         return 0;
1859
1860 err_reg_dev:
1861         free_netdev(sitn->fb_tunnel_dev);
1862 err_alloc_dev:
1863         return err;
1864 }
1865
1866 static void __net_exit sit_exit_net(struct net *net)
1867 {
1868         LIST_HEAD(list);
1869
1870         rtnl_lock();
1871         sit_destroy_tunnels(net, &list);
1872         unregister_netdevice_many(&list);
1873         rtnl_unlock();
1874 }
1875
1876 static struct pernet_operations sit_net_ops = {
1877         .init = sit_init_net,
1878         .exit = sit_exit_net,
1879         .id   = &sit_net_id,
1880         .size = sizeof(struct sit_net),
1881 };
1882
1883 static void __exit sit_cleanup(void)
1884 {
1885         rtnl_link_unregister(&sit_link_ops);
1886         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1887         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1888 #if IS_ENABLED(CONFIG_MPLS)
1889         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1890 #endif
1891
1892         unregister_pernet_device(&sit_net_ops);
1893         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1894 }
1895
1896 static int __init sit_init(void)
1897 {
1898         int err;
1899
1900         pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1901
1902         err = register_pernet_device(&sit_net_ops);
1903         if (err < 0)
1904                 return err;
1905         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1906         if (err < 0) {
1907                 pr_info("%s: can't register ip6ip4\n", __func__);
1908                 goto xfrm_tunnel_failed;
1909         }
1910         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1911         if (err < 0) {
1912                 pr_info("%s: can't register ip4ip4\n", __func__);
1913                 goto xfrm_tunnel4_failed;
1914         }
1915 #if IS_ENABLED(CONFIG_MPLS)
1916         err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1917         if (err < 0) {
1918                 pr_info("%s: can't register mplsip\n", __func__);
1919                 goto xfrm_tunnel_mpls_failed;
1920         }
1921 #endif
1922         err = rtnl_link_register(&sit_link_ops);
1923         if (err < 0)
1924                 goto rtnl_link_failed;
1925
1926 out:
1927         return err;
1928
1929 rtnl_link_failed:
1930 #if IS_ENABLED(CONFIG_MPLS)
1931         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1932 xfrm_tunnel_mpls_failed:
1933 #endif
1934         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1935 xfrm_tunnel4_failed:
1936         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1937 xfrm_tunnel_failed:
1938         unregister_pernet_device(&sit_net_ops);
1939         goto out;
1940 }
1941
1942 module_init(sit_init);
1943 module_exit(sit_cleanup);
1944 MODULE_LICENSE("GPL");
1945 MODULE_ALIAS_RTNL_LINK("sit");
1946 MODULE_ALIAS_NETDEV("sit0");