net/ipv6/sit.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   4  *      Linux INET6 implementation
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <[email protected]>
   8  *      Alexey Kuznetsov        <[email protected]>
   9  *
  10  *      Changes:
  11  * Roger Venning <[email protected]>:       6to4 support
  12  * Nate Thompson <[email protected]>:             6to4 support
  13  * Fred Templin <[email protected]>:    isatap support
  14  */
  15
  16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  17
  18 #include <linux/module.h>
  19 #include <linux/capability.h>
  20 #include <linux/errno.h>
  21 #include <linux/types.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/net.h>
  25 #include <linux/in6.h>
  26 #include <linux/netdevice.h>
  27 #include <linux/if_arp.h>
  28 #include <linux/icmp.h>
  29 #include <linux/slab.h>
  30 #include <linux/uaccess.h>
  31 #include <linux/init.h>
  32 #include <linux/netfilter_ipv4.h>
  33 #include <linux/if_ether.h>
  34
  35 #include <net/sock.h>
  36 #include <net/snmp.h>
  37
  38 #include <net/ipv6.h>
  39 #include <net/protocol.h>
  40 #include <net/transp_v6.h>
  41 #include <net/ip6_fib.h>
  42 #include <net/ip6_route.h>
  43 #include <net/ndisc.h>
  44 #include <net/addrconf.h>
  45 #include <net/ip.h>
  46 #include <net/udp.h>
  47 #include <net/icmp.h>
  48 #include <net/ip_tunnels.h>
  49 #include <net/inet_ecn.h>
  50 #include <net/xfrm.h>
  51 #include <net/dsfield.h>
  52 #include <net/net_namespace.h>
  53 #include <net/netns/generic.h>
  54 #include <net/inet_dscp.h>
  55
  56 /*
  57    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  58
  59    For comments look at net/ipv4/ip_gre.c --ANK
  60  */
  61
  62 #define IP6_SIT_HASH_SIZE  16
  63 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  64
  65 static bool log_ecn_error = true;
  66 module_param(log_ecn_error, bool, 0644);
  67 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  68
  69 static int ipip6_tunnel_init(struct net_device *dev);
  70 static void ipip6_tunnel_setup(struct net_device *dev);
  71 static void ipip6_dev_free(struct net_device *dev);
  72 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  73                       __be32 *v4dst);
  74 static struct rtnl_link_ops sit_link_ops __read_mostly;
  75
  76 static unsigned int sit_net_id __read_mostly;
  77 struct sit_net {
  78         struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
  79         struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
  80         struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
  81         struct ip_tunnel __rcu *tunnels_wc[1];
  82         struct ip_tunnel __rcu **tunnels[4];
  83
  84         struct net_device *fb_tunnel_dev;
  85 };
  86
  87 static inline struct sit_net *dev_to_sit_net(struct net_device *dev)
  88 {
  89         struct ip_tunnel *t = netdev_priv(dev);
  90
  91         return net_generic(t->net, sit_net_id);
  92 }
  93
  94 /*
  95  * Must be invoked with rcu_read_lock
  96  */
  97 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  98                                              struct net_device *dev,
  99                                              __be32 remote, __be32 local,
 100                                              int sifindex)
 101 {
 102         unsigned int h0 = HASH(remote);
 103         unsigned int h1 = HASH(local);
 104         struct ip_tunnel *t;
 105         struct sit_net *sitn = net_generic(net, sit_net_id);
 106         int ifindex = dev ? dev->ifindex : 0;
 107
 108         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 109                 if (local == t->parms.iph.saddr &&
 110                     remote == t->parms.iph.daddr &&
 111                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 112                      sifindex == t->parms.link) &&
 113                     (t->dev->flags & IFF_UP))
 114                         return t;
 115         }
 116         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 117                 if (remote == t->parms.iph.daddr &&
 118                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 119                      sifindex == t->parms.link) &&
 120                     (t->dev->flags & IFF_UP))
 121                         return t;
 122         }
 123         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 124                 if (local == t->parms.iph.saddr &&
 125                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 126                      sifindex == t->parms.link) &&
 127                     (t->dev->flags & IFF_UP))
 128                         return t;
 129         }
 130         t = rcu_dereference(sitn->tunnels_wc[0]);
 131         if (t && (t->dev->flags & IFF_UP))
 132                 return t;
 133         return NULL;
 134 }
 135
 136 static struct ip_tunnel __rcu **
 137 __ipip6_bucket(struct sit_net *sitn, struct ip_tunnel_parm_kern *parms)
 138 {
 139         __be32 remote = parms->iph.daddr;
 140         __be32 local = parms->iph.saddr;
 141         unsigned int h = 0;
 142         int prio = 0;
 143
 144         if (remote) {
 145                 prio |= 2;
 146                 h ^= HASH(remote);
 147         }
 148         if (local) {
 149                 prio |= 1;
 150                 h ^= HASH(local);
 151         }
 152         return &sitn->tunnels[prio][h];
 153 }
 154
 155 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 156                 struct ip_tunnel *t)
 157 {
 158         return __ipip6_bucket(sitn, &t->parms);
 159 }
 160
 161 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 162 {
 163         struct ip_tunnel __rcu **tp;
 164         struct ip_tunnel *iter;
 165
 166         for (tp = ipip6_bucket(sitn, t);
 167              (iter = rtnl_dereference(*tp)) != NULL;
 168              tp = &iter->next) {
 169                 if (t == iter) {
 170                         rcu_assign_pointer(*tp, t->next);
 171                         break;
 172                 }
 173         }
 174 }
 175
 176 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 177 {
 178         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 179
 180         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 181         rcu_assign_pointer(*tp, t);
 182 }
 183
 184 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 185 {
 186 #ifdef CONFIG_IPV6_SIT_6RD
 187         struct ip_tunnel *t = netdev_priv(dev);
 188
 189         if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
 190                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 191                 t->ip6rd.relay_prefix = 0;
 192                 t->ip6rd.prefixlen = 16;
 193                 t->ip6rd.relay_prefixlen = 0;
 194         } else {
 195                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 196                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 197         }
 198 #endif
 199 }
 200
 201 static int ipip6_tunnel_create(struct net_device *dev)
 202 {
 203         struct ip_tunnel *t = netdev_priv(dev);
 204         struct net *net = dev_net(dev);
 205         struct sit_net *sitn = net_generic(net, sit_net_id);
 206         int err;
 207
 208         __dev_addr_set(dev, &t->parms.iph.saddr, 4);
 209         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 210
 211         if (test_bit(IP_TUNNEL_SIT_ISATAP_BIT, t->parms.i_flags))
 212                 dev->priv_flags |= IFF_ISATAP;
 213
 214         dev->rtnl_link_ops = &sit_link_ops;
 215
 216         err = register_netdevice(dev);
 217         if (err < 0)
 218                 goto out;
 219
 220         ipip6_tunnel_clone_6rd(dev, sitn);
 221
 222         ipip6_tunnel_link(sitn, t);
 223         return 0;
 224
 225 out:
 226         return err;
 227 }
 228
 229 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 230                                              struct ip_tunnel_parm_kern *parms,
 231                                              int create)
 232 {
 233         __be32 remote = parms->iph.daddr;
 234         __be32 local = parms->iph.saddr;
 235         struct ip_tunnel *t, *nt;
 236         struct ip_tunnel __rcu **tp;
 237         struct net_device *dev;
 238         char name[IFNAMSIZ];
 239         struct sit_net *sitn = net_generic(net, sit_net_id);
 240
 241         for (tp = __ipip6_bucket(sitn, parms);
 242             (t = rtnl_dereference(*tp)) != NULL;
 243              tp = &t->next) {
 244                 if (local == t->parms.iph.saddr &&
 245                     remote == t->parms.iph.daddr &&
 246                     parms->link == t->parms.link) {
 247                         if (create)
 248                                 return NULL;
 249                         else
 250                                 return t;
 251                 }
 252         }
 253         if (!create)
 254                 goto failed;
 255
 256         if (parms->name[0]) {
 257                 if (!dev_valid_name(parms->name))
 258                         goto failed;
 259                 strscpy(name, parms->name, IFNAMSIZ);
 260         } else {
 261                 strcpy(name, "sit%d");
 262         }
 263         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 264                            ipip6_tunnel_setup);
 265         if (!dev)
 266                 return NULL;
 267
 268         dev_net_set(dev, net);
 269
 270         nt = netdev_priv(dev);
 271
 272         nt->parms = *parms;
 273         if (ipip6_tunnel_create(dev) < 0)
 274                 goto failed_free;
 275
 276         if (!parms->name[0])
 277                 strcpy(parms->name, dev->name);
 278
 279         return nt;
 280
 281 failed_free:
 282         free_netdev(dev);
 283 failed:
 284         return NULL;
 285 }
 286
 287 #define for_each_prl_rcu(start)                 \
 288         for (prl = rcu_dereference(start);      \
 289              prl;                               \
 290              prl = rcu_dereference(prl->next))
 291
 292 static struct ip_tunnel_prl_entry *
 293 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 294 {
 295         struct ip_tunnel_prl_entry *prl;
 296
 297         for_each_prl_rcu(t->prl)
 298                 if (prl->addr == addr)
 299                         break;
 300         return prl;
 301
 302 }
 303
 304 static int ipip6_tunnel_get_prl(struct net_device *dev, struct ip_tunnel_prl __user *a)
 305 {
 306         struct ip_tunnel *t = netdev_priv(dev);
 307         struct ip_tunnel_prl kprl, *kp;
 308         struct ip_tunnel_prl_entry *prl;
 309         unsigned int cmax, c = 0, ca, len;
 310         int ret = 0;
 311
 312         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
 313                 return -EINVAL;
 314
 315         if (copy_from_user(&kprl, a, sizeof(kprl)))
 316                 return -EFAULT;
 317         cmax = kprl.datalen / sizeof(kprl);
 318         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 319                 cmax = 1;
 320
 321         /* For simple GET or for root users,
 322          * we try harder to allocate.
 323          */
 324         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 325                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL_ACCOUNT | __GFP_NOWARN) :
 326                 NULL;
 327
 328         ca = min(t->prl_count, cmax);
 329
 330         if (!kp) {
 331                 /* We don't try hard to allocate much memory for
 332                  * non-root users.
 333                  * For root users, retry allocating enough memory for
 334                  * the answer.
 335                  */
 336                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC | __GFP_ACCOUNT |
 337                                               __GFP_NOWARN);
 338                 if (!kp) {
 339                         ret = -ENOMEM;
 340                         goto out;
 341                 }
 342         }
 343
 344         rcu_read_lock();
 345         for_each_prl_rcu(t->prl) {
 346                 if (c >= cmax)
 347                         break;
 348                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 349                         continue;
 350                 kp[c].addr = prl->addr;
 351                 kp[c].flags = prl->flags;
 352                 c++;
 353                 if (kprl.addr != htonl(INADDR_ANY))
 354                         break;
 355         }
 356
 357         rcu_read_unlock();
 358
 359         len = sizeof(*kp) * c;
 360         ret = 0;
 361         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 362                 ret = -EFAULT;
 363
 364         kfree(kp);
 365 out:
 366         return ret;
 367 }
 368
 369 static int
 370 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 371 {
 372         struct ip_tunnel_prl_entry *p;
 373         int err = 0;
 374
 375         if (a->addr == htonl(INADDR_ANY))
 376                 return -EINVAL;
 377
 378         ASSERT_RTNL();
 379
 380         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 381                 if (p->addr == a->addr) {
 382                         if (chg) {
 383                                 p->flags = a->flags;
 384                                 goto out;
 385                         }
 386                         err = -EEXIST;
 387                         goto out;
 388                 }
 389         }
 390
 391         if (chg) {
 392                 err = -ENXIO;
 393                 goto out;
 394         }
 395
 396         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 397         if (!p) {
 398                 err = -ENOBUFS;
 399                 goto out;
 400         }
 401
 402         p->next = t->prl;
 403         p->addr = a->addr;
 404         p->flags = a->flags;
 405         t->prl_count++;
 406         rcu_assign_pointer(t->prl, p);
 407 out:
 408         return err;
 409 }
 410
 411 static void prl_list_destroy_rcu(struct rcu_head *head)
 412 {
 413         struct ip_tunnel_prl_entry *p, *n;
 414
 415         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 416         do {
 417                 n = rcu_dereference_protected(p->next, 1);
 418                 kfree(p);
 419                 p = n;
 420         } while (p);
 421 }
 422
 423 static int
 424 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 425 {
 426         struct ip_tunnel_prl_entry *x;
 427         struct ip_tunnel_prl_entry __rcu **p;
 428         int err = 0;
 429
 430         ASSERT_RTNL();
 431
 432         if (a && a->addr != htonl(INADDR_ANY)) {
 433                 for (p = &t->prl;
 434                      (x = rtnl_dereference(*p)) != NULL;
 435                      p = &x->next) {
 436                         if (x->addr == a->addr) {
 437                                 *p = x->next;
 438                                 kfree_rcu(x, rcu_head);
 439                                 t->prl_count--;
 440                                 goto out;
 441                         }
 442                 }
 443                 err = -ENXIO;
 444         } else {
 445                 x = rtnl_dereference(t->prl);
 446                 if (x) {
 447                         t->prl_count = 0;
 448                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 449                         t->prl = NULL;
 450                 }
 451         }
 452 out:
 453         return err;
 454 }
 455
 456 static int ipip6_tunnel_prl_ctl(struct net_device *dev,
 457                                 struct ip_tunnel_prl __user *data, int cmd)
 458 {
 459         struct ip_tunnel *t = netdev_priv(dev);
 460         struct ip_tunnel_prl prl;
 461         int err;
 462
 463         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
 464                 return -EPERM;
 465         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
 466                 return -EINVAL;
 467
 468         if (copy_from_user(&prl, data, sizeof(prl)))
 469                 return -EFAULT;
 470
 471         switch (cmd) {
 472         case SIOCDELPRL:
 473                 err = ipip6_tunnel_del_prl(t, &prl);
 474                 break;
 475         case SIOCADDPRL:
 476         case SIOCCHGPRL:
 477                 err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 478                 break;
 479         }
 480         dst_cache_reset(&t->dst_cache);
 481         netdev_state_change(dev);
 482         return err;
 483 }
 484
 485 static int
 486 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 487 {
 488         struct ip_tunnel_prl_entry *p;
 489         int ok = 1;
 490
 491         rcu_read_lock();
 492         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 493         if (p) {
 494                 if (p->flags & PRL_DEFAULT)
 495                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 496                 else
 497                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 498         } else {
 499                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 500
 501                 if (ipv6_addr_is_isatap(addr6) &&
 502                     (addr6->s6_addr32[3] == iph->saddr) &&
 503                     ipv6_chk_prefix(addr6, t->dev))
 504                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 505                 else
 506                         ok = 0;
 507         }
 508         rcu_read_unlock();
 509         return ok;
 510 }
 511
 512 static void ipip6_tunnel_uninit(struct net_device *dev)
 513 {
 514         struct ip_tunnel *tunnel = netdev_priv(dev);
 515         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 516
 517         if (dev == sitn->fb_tunnel_dev) {
 518                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 519         } else {
 520                 ipip6_tunnel_unlink(sitn, tunnel);
 521                 ipip6_tunnel_del_prl(tunnel, NULL);
 522         }
 523         dst_cache_reset(&tunnel->dst_cache);
 524         netdev_put(dev, &tunnel->dev_tracker);
 525 }
 526
 527 static int ipip6_err(struct sk_buff *skb, u32 info)
 528 {
 529         const struct iphdr *iph = (const struct iphdr *)skb->data;
 530         const int type = icmp_hdr(skb)->type;
 531         const int code = icmp_hdr(skb)->code;
 532         unsigned int data_len = 0;
 533         struct ip_tunnel *t;
 534         int sifindex;
 535         int err;
 536
 537         switch (type) {
 538         default:
 539         case ICMP_PARAMETERPROB:
 540                 return 0;
 541
 542         case ICMP_DEST_UNREACH:
 543                 switch (code) {
 544                 case ICMP_SR_FAILED:
 545                         /* Impossible event. */
 546                         return 0;
 547                 default:
 548                         /* All others are translated to HOST_UNREACH.
 549                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 550                            I believe they are just ether pollution. --ANK
 551                          */
 552                         break;
 553                 }
 554                 break;
 555         case ICMP_TIME_EXCEEDED:
 556                 if (code != ICMP_EXC_TTL)
 557                         return 0;
 558                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 559                 break;
 560         case ICMP_REDIRECT:
 561                 break;
 562         }
 563
 564         err = -ENOENT;
 565
 566         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 567         t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 568                                 iph->daddr, iph->saddr, sifindex);
 569         if (!t)
 570                 goto out;
 571
 572         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 573                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 574                                  t->parms.link, iph->protocol);
 575                 err = 0;
 576                 goto out;
 577         }
 578         if (type == ICMP_REDIRECT) {
 579                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
 580                               iph->protocol);
 581                 err = 0;
 582                 goto out;
 583         }
 584
 585         err = 0;
 586         if (__in6_dev_get(skb->dev) &&
 587             !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 588                 goto out;
 589
 590         if (t->parms.iph.daddr == 0)
 591                 goto out;
 592
 593         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 594                 goto out;
 595
 596         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 597                 t->err_count++;
 598         else
 599                 t->err_count = 1;
 600         t->err_time = jiffies;
 601 out:
 602         return err;
 603 }
 604
 605 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 606                                   const struct in6_addr *v6addr)
 607 {
 608         __be32 v4embed = 0;
 609         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 610                 return true;
 611         return false;
 612 }
 613
 614 /* Checks if an address matches an address on the tunnel interface.
 615  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 616  * Long story:
 617  * This function is called after we considered the packet as spoofed
 618  * in is_spoofed_6rd.
 619  * We may have a router that is doing NAT for proto 41 packets
 620  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 621  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 622  * function will return true, dropping the packet.
 623  * But, we can still check if is spoofed against the IP
 624  * addresses associated with the interface.
 625  */
 626 static bool only_dnatted(const struct ip_tunnel *tunnel,
 627         const struct in6_addr *v6dst)
 628 {
 629         int prefix_len;
 630
 631 #ifdef CONFIG_IPV6_SIT_6RD
 632         prefix_len = tunnel->ip6rd.prefixlen + 32
 633                 - tunnel->ip6rd.relay_prefixlen;
 634 #else
 635         prefix_len = 48;
 636 #endif
 637         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 638 }
 639
 640 /* Returns true if a packet is spoofed */
 641 static bool packet_is_spoofed(struct sk_buff *skb,
 642                               const struct iphdr *iph,
 643                               struct ip_tunnel *tunnel)
 644 {
 645         const struct ipv6hdr *ipv6h;
 646
 647         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 648                 if (!isatap_chksrc(skb, iph, tunnel))
 649                         return true;
 650
 651                 return false;
 652         }
 653
 654         if (tunnel->dev->flags & IFF_POINTOPOINT)
 655                 return false;
 656
 657         ipv6h = ipv6_hdr(skb);
 658
 659         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 660                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 661                                      &iph->saddr, &ipv6h->saddr,
 662                                      &iph->daddr, &ipv6h->daddr);
 663                 return true;
 664         }
 665
 666         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 667                 return false;
 668
 669         if (only_dnatted(tunnel, &ipv6h->daddr))
 670                 return false;
 671
 672         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 673                              &iph->saddr, &ipv6h->saddr,
 674                              &iph->daddr, &ipv6h->daddr);
 675         return true;
 676 }
 677
 678 static int ipip6_rcv(struct sk_buff *skb)
 679 {
 680         const struct iphdr *iph = ip_hdr(skb);
 681         struct ip_tunnel *tunnel;
 682         int sifindex;
 683         int err;
 684
 685         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 686         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 687                                      iph->saddr, iph->daddr, sifindex);
 688         if (tunnel) {
 689                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 690                     tunnel->parms.iph.protocol != 0)
 691                         goto out;
 692
 693                 skb->mac_header = skb->network_header;
 694                 skb_reset_network_header(skb);
 695                 IPCB(skb)->flags = 0;
 696                 skb->dev = tunnel->dev;
 697
 698                 if (packet_is_spoofed(skb, iph, tunnel)) {
 699                         DEV_STATS_INC(tunnel->dev, rx_errors);
 700                         goto out;
 701                 }
 702
 703                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 704                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
 705                         goto out;
 706
 707                 /* skb can be uncloned in iptunnel_pull_header, so
 708                  * old iph is no longer valid
 709                  */
 710                 iph = (const struct iphdr *)skb_mac_header(skb);
 711                 skb_reset_mac_header(skb);
 712
 713                 err = IP_ECN_decapsulate(iph, skb);
 714                 if (unlikely(err)) {
 715                         if (log_ecn_error)
 716                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 717                                                      &iph->saddr, iph->tos);
 718                         if (err > 1) {
 719                                 DEV_STATS_INC(tunnel->dev, rx_frame_errors);
 720                                 DEV_STATS_INC(tunnel->dev, rx_errors);
 721                                 goto out;
 722                         }
 723                 }
 724
 725                 dev_sw_netstats_rx_add(tunnel->dev, skb->len);
 726
 727                 netif_rx(skb);
 728
 729                 return 0;
 730         }
 731
 732         /* no tunnel matched,  let upstream know, ipsec may handle it */
 733         return 1;
 734 out:
 735         kfree_skb(skb);
 736         return 0;
 737 }
 738
 739 static const struct tnl_ptk_info ipip_tpi = {
 740         /* no tunnel info required for ipip. */
 741         .proto = htons(ETH_P_IP),
 742 };
 743
 744 #if IS_ENABLED(CONFIG_MPLS)
 745 static const struct tnl_ptk_info mplsip_tpi = {
 746         /* no tunnel info required for mplsip. */
 747         .proto = htons(ETH_P_MPLS_UC),
 748 };
 749 #endif
 750
 751 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 752 {
 753         const struct iphdr *iph;
 754         struct ip_tunnel *tunnel;
 755         int sifindex;
 756
 757         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 758
 759         iph = ip_hdr(skb);
 760         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 761                                      iph->saddr, iph->daddr, sifindex);
 762         if (tunnel) {
 763                 const struct tnl_ptk_info *tpi;
 764
 765                 if (tunnel->parms.iph.protocol != ipproto &&
 766                     tunnel->parms.iph.protocol != 0)
 767                         goto drop;
 768
 769                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 770                         goto drop;
 771 #if IS_ENABLED(CONFIG_MPLS)
 772                 if (ipproto == IPPROTO_MPLS)
 773                         tpi = &mplsip_tpi;
 774                 else
 775 #endif
 776                         tpi = &ipip_tpi;
 777                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
 778                         goto drop;
 779                 skb_reset_mac_header(skb);
 780
 781                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 782         }
 783
 784         return 1;
 785
 786 drop:
 787         kfree_skb(skb);
 788         return 0;
 789 }
 790
 791 static int ipip_rcv(struct sk_buff *skb)
 792 {
 793         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
 794 }
 795
 796 #if IS_ENABLED(CONFIG_MPLS)
 797 static int mplsip_rcv(struct sk_buff *skb)
 798 {
 799         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
 800 }
 801 #endif
 802
 803 /*
 804  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 805  * stores the embedded IPv4 address in v4dst and returns true.
 806  */
 807 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 808                       __be32 *v4dst)
 809 {
 810 #ifdef CONFIG_IPV6_SIT_6RD
 811         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 812                               tunnel->ip6rd.prefixlen)) {
 813                 unsigned int pbw0, pbi0;
 814                 int pbi1;
 815                 u32 d;
 816
 817                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 818                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 819
 820                 d = tunnel->ip6rd.relay_prefixlen < 32 ?
 821                         (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 822                     tunnel->ip6rd.relay_prefixlen : 0;
 823
 824                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 825                 if (pbi1 > 0)
 826                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 827                              (32 - pbi1);
 828
 829                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 830                 return true;
 831         }
 832 #else
 833         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 834                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 835                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 836                 return true;
 837         }
 838 #endif
 839         return false;
 840 }
 841
 842 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 843                              const struct in6_addr *v6dst)
 844 {
 845         __be32 dst = 0;
 846         check_6rd(tunnel, v6dst, &dst);
 847         return dst;
 848 }
 849
 850 /*
 851  *      This function assumes it is being called from dev_queue_xmit()
 852  *      and that skb is filled properly by that function.
 853  */
 854
 855 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 856                                      struct net_device *dev)
 857 {
 858         struct ip_tunnel *tunnel = netdev_priv(dev);
 859         const struct iphdr  *tiph = &tunnel->parms.iph;
 860         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 861         u8     tos = tunnel->parms.iph.tos;
 862         __be16 df = tiph->frag_off;
 863         struct rtable *rt;              /* Route to the other host */
 864         struct net_device *tdev;        /* Device to other host */
 865         unsigned int max_headroom;      /* The extra header space needed */
 866         __be32 dst = tiph->daddr;
 867         struct flowi4 fl4;
 868         int    mtu;
 869         const struct in6_addr *addr6;
 870         int addr_type;
 871         u8 ttl;
 872         u8 protocol = IPPROTO_IPV6;
 873         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 874
 875         if (tos == 1)
 876                 tos = ipv6_get_dsfield(iph6);
 877
 878         /* ISATAP (RFC4214) - must come before 6to4 */
 879         if (dev->priv_flags & IFF_ISATAP) {
 880                 struct neighbour *neigh = NULL;
 881                 bool do_tx_error = false;
 882
 883                 if (skb_dst(skb))
 884                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 885
 886                 if (!neigh) {
 887                         net_dbg_ratelimited("nexthop == NULL\n");
 888                         goto tx_error;
 889                 }
 890
 891                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 892                 addr_type = ipv6_addr_type(addr6);
 893
 894                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 895                      ipv6_addr_is_isatap(addr6))
 896                         dst = addr6->s6_addr32[3];
 897                 else
 898                         do_tx_error = true;
 899
 900                 neigh_release(neigh);
 901                 if (do_tx_error)
 902                         goto tx_error;
 903         }
 904
 905         if (!dst)
 906                 dst = try_6rd(tunnel, &iph6->daddr);
 907
 908         if (!dst) {
 909                 struct neighbour *neigh = NULL;
 910                 bool do_tx_error = false;
 911
 912                 if (skb_dst(skb))
 913                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 914
 915                 if (!neigh) {
 916                         net_dbg_ratelimited("nexthop == NULL\n");
 917                         goto tx_error;
 918                 }
 919
 920                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 921                 addr_type = ipv6_addr_type(addr6);
 922
 923                 if (addr_type == IPV6_ADDR_ANY) {
 924                         addr6 = &ipv6_hdr(skb)->daddr;
 925                         addr_type = ipv6_addr_type(addr6);
 926                 }
 927
 928                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 929                         dst = addr6->s6_addr32[3];
 930                 else
 931                         do_tx_error = true;
 932
 933                 neigh_release(neigh);
 934                 if (do_tx_error)
 935                         goto tx_error;
 936         }
 937
 938         flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
 939                            tos & INET_DSCP_MASK, RT_SCOPE_UNIVERSE,
 940                            IPPROTO_IPV6, 0, dst, tiph->saddr, 0, 0,
 941                            sock_net_uid(tunnel->net, NULL));
 942
 943         rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
 944         if (!rt) {
 945                 rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
 946                 if (IS_ERR(rt)) {
 947                         DEV_STATS_INC(dev, tx_carrier_errors);
 948                         goto tx_error_icmp;
 949                 }
 950                 dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
 951         }
 952
 953         if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
 954                 ip_rt_put(rt);
 955                 DEV_STATS_INC(dev, tx_carrier_errors);
 956                 goto tx_error_icmp;
 957         }
 958         tdev = rt->dst.dev;
 959
 960         if (tdev == dev) {
 961                 ip_rt_put(rt);
 962                 DEV_STATS_INC(dev, collisions);
 963                 goto tx_error;
 964         }
 965
 966         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 967                 ip_rt_put(rt);
 968                 goto tx_error;
 969         }
 970
 971         if (df) {
 972                 mtu = dst_mtu(&rt->dst) - t_hlen;
 973
 974                 if (mtu < IPV4_MIN_MTU) {
 975                         DEV_STATS_INC(dev, collisions);
 976                         ip_rt_put(rt);
 977                         goto tx_error;
 978                 }
 979
 980                 if (mtu < IPV6_MIN_MTU) {
 981                         mtu = IPV6_MIN_MTU;
 982                         df = 0;
 983                 }
 984
 985                 if (tunnel->parms.iph.daddr)
 986                         skb_dst_update_pmtu_no_confirm(skb, mtu);
 987
 988                 if (skb->len > mtu && !skb_is_gso(skb)) {
 989                         icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 990                         ip_rt_put(rt);
 991                         goto tx_error;
 992                 }
 993         }
 994
 995         if (tunnel->err_count > 0) {
 996                 if (time_before(jiffies,
 997                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 998                         tunnel->err_count--;
 999                         dst_link_failure(skb);
1000                 } else
1001                         tunnel->err_count = 0;
1002         }
1003
1004         /*
1005          * Okay, now see if we can stuff it in the buffer as-is.
1006          */
1007         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
1008
1009         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1010             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1011                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
1012                 if (!new_skb) {
1013                         ip_rt_put(rt);
1014                         DEV_STATS_INC(dev, tx_dropped);
1015                         kfree_skb(skb);
1016                         return NETDEV_TX_OK;
1017                 }
1018                 if (skb->sk)
1019                         skb_set_owner_w(new_skb, skb->sk);
1020                 dev_kfree_skb(skb);
1021                 skb = new_skb;
1022                 iph6 = ipv6_hdr(skb);
1023         }
1024         ttl = tiph->ttl;
1025         if (ttl == 0)
1026                 ttl = iph6->hop_limit;
1027         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
1028
1029         if (ip_tunnel_encap(skb, &tunnel->encap, &protocol, &fl4) < 0) {
1030                 ip_rt_put(rt);
1031                 goto tx_error;
1032         }
1033
1034         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
1035
1036         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
1037                       df, !net_eq(tunnel->net, dev_net(dev)));
1038         return NETDEV_TX_OK;
1039
1040 tx_error_icmp:
1041         dst_link_failure(skb);
1042 tx_error:
1043         kfree_skb(skb);
1044         DEV_STATS_INC(dev, tx_errors);
1045         return NETDEV_TX_OK;
1046 }
1047
1048 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1049                                      struct net_device *dev, u8 ipproto)
1050 {
1051         struct ip_tunnel *tunnel = netdev_priv(dev);
1052         const struct iphdr  *tiph = &tunnel->parms.iph;
1053
1054         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1055                 goto tx_error;
1056
1057         skb_set_inner_ipproto(skb, ipproto);
1058
1059         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1060         return NETDEV_TX_OK;
1061 tx_error:
1062         kfree_skb(skb);
1063         DEV_STATS_INC(dev, tx_errors);
1064         return NETDEV_TX_OK;
1065 }
1066
1067 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1068                                    struct net_device *dev)
1069 {
1070         if (!pskb_inet_may_pull(skb))
1071                 goto tx_err;
1072
1073         switch (skb->protocol) {
1074         case htons(ETH_P_IP):
1075                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1076                 break;
1077         case htons(ETH_P_IPV6):
1078                 ipip6_tunnel_xmit(skb, dev);
1079                 break;
1080 #if IS_ENABLED(CONFIG_MPLS)
1081         case htons(ETH_P_MPLS_UC):
1082                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1083                 break;
1084 #endif
1085         default:
1086                 goto tx_err;
1087         }
1088
1089         return NETDEV_TX_OK;
1090
1091 tx_err:
1092         DEV_STATS_INC(dev, tx_errors);
1093         kfree_skb(skb);
1094         return NETDEV_TX_OK;
1095
1096 }
1097
1098 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1099 {
1100         struct ip_tunnel *tunnel = netdev_priv(dev);
1101         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1102         struct net_device *tdev = NULL;
1103         int hlen = LL_MAX_HEADER;
1104         const struct iphdr *iph;
1105         struct flowi4 fl4;
1106
1107         iph = &tunnel->parms.iph;
1108
1109         if (iph->daddr) {
1110                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1111                                                           NULL,
1112                                                           iph->daddr, iph->saddr,
1113                                                           0, 0,
1114                                                           IPPROTO_IPV6,
1115                                                           iph->tos & INET_DSCP_MASK,
1116                                                           tunnel->parms.link);
1117
1118                 if (!IS_ERR(rt)) {
1119                         tdev = rt->dst.dev;
1120                         ip_rt_put(rt);
1121                 }
1122                 dev->flags |= IFF_POINTOPOINT;
1123         }
1124
1125         if (!tdev && tunnel->parms.link)
1126                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1127
1128         if (tdev && !netif_is_l3_master(tdev)) {
1129                 int mtu;
1130
1131                 mtu = tdev->mtu - t_hlen;
1132                 if (mtu < IPV6_MIN_MTU)
1133                         mtu = IPV6_MIN_MTU;
1134                 WRITE_ONCE(dev->mtu, mtu);
1135                 hlen = tdev->hard_header_len + tdev->needed_headroom;
1136         }
1137         dev->needed_headroom = t_hlen + hlen;
1138 }
1139
1140 static void ipip6_tunnel_update(struct ip_tunnel *t,
1141                                 struct ip_tunnel_parm_kern *p,
1142                                 __u32 fwmark)
1143 {
1144         struct net *net = t->net;
1145         struct sit_net *sitn = net_generic(net, sit_net_id);
1146
1147         ipip6_tunnel_unlink(sitn, t);
1148         synchronize_net();
1149         t->parms.iph.saddr = p->iph.saddr;
1150         t->parms.iph.daddr = p->iph.daddr;
1151         __dev_addr_set(t->dev, &p->iph.saddr, 4);
1152         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1153         ipip6_tunnel_link(sitn, t);
1154         t->parms.iph.ttl = p->iph.ttl;
1155         t->parms.iph.tos = p->iph.tos;
1156         t->parms.iph.frag_off = p->iph.frag_off;
1157         if (t->parms.link != p->link || t->fwmark != fwmark) {
1158                 t->parms.link = p->link;
1159                 t->fwmark = fwmark;
1160                 ipip6_tunnel_bind_dev(t->dev);
1161         }
1162         dst_cache_reset(&t->dst_cache);
1163         netdev_state_change(t->dev);
1164 }
1165
1166 #ifdef CONFIG_IPV6_SIT_6RD
1167 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1168                                    struct ip_tunnel_6rd *ip6rd)
1169 {
1170         struct in6_addr prefix;
1171         __be32 relay_prefix;
1172
1173         if (ip6rd->relay_prefixlen > 32 ||
1174             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1175                 return -EINVAL;
1176
1177         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1178         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1179                 return -EINVAL;
1180         if (ip6rd->relay_prefixlen)
1181                 relay_prefix = ip6rd->relay_prefix &
1182                                htonl(0xffffffffUL <<
1183                                      (32 - ip6rd->relay_prefixlen));
1184         else
1185                 relay_prefix = 0;
1186         if (relay_prefix != ip6rd->relay_prefix)
1187                 return -EINVAL;
1188
1189         t->ip6rd.prefix = prefix;
1190         t->ip6rd.relay_prefix = relay_prefix;
1191         t->ip6rd.prefixlen = ip6rd->prefixlen;
1192         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1193         dst_cache_reset(&t->dst_cache);
1194         netdev_state_change(t->dev);
1195         return 0;
1196 }
1197
1198 static int
1199 ipip6_tunnel_get6rd(struct net_device *dev, struct ip_tunnel_parm __user *data)
1200 {
1201         struct ip_tunnel *t = netdev_priv(dev);
1202         struct ip_tunnel_parm_kern p;
1203         struct ip_tunnel_6rd ip6rd;
1204
1205         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1206                 if (!ip_tunnel_parm_from_user(&p, data))
1207                         return -EFAULT;
1208                 t = ipip6_tunnel_locate(t->net, &p, 0);
1209         }
1210         if (!t)
1211                 t = netdev_priv(dev);
1212
1213         ip6rd.prefix = t->ip6rd.prefix;
1214         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1215         ip6rd.prefixlen = t->ip6rd.prefixlen;
1216         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1217         if (copy_to_user(data, &ip6rd, sizeof(ip6rd)))
1218                 return -EFAULT;
1219         return 0;
1220 }
1221
1222 static int
1223 ipip6_tunnel_6rdctl(struct net_device *dev, struct ip_tunnel_6rd __user *data,
1224                     int cmd)
1225 {
1226         struct ip_tunnel *t = netdev_priv(dev);
1227         struct ip_tunnel_6rd ip6rd;
1228         int err;
1229
1230         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1231                 return -EPERM;
1232         if (copy_from_user(&ip6rd, data, sizeof(ip6rd)))
1233                 return -EFAULT;
1234
1235         if (cmd != SIOCDEL6RD) {
1236                 err = ipip6_tunnel_update_6rd(t, &ip6rd);
1237                 if (err < 0)
1238                         return err;
1239         } else
1240                 ipip6_tunnel_clone_6rd(dev, dev_to_sit_net(dev));
1241         return 0;
1242 }
1243
1244 #endif /* CONFIG_IPV6_SIT_6RD */
1245
1246 static bool ipip6_valid_ip_proto(u8 ipproto)
1247 {
1248         return ipproto == IPPROTO_IPV6 ||
1249                 ipproto == IPPROTO_IPIP ||
1250 #if IS_ENABLED(CONFIG_MPLS)
1251                 ipproto == IPPROTO_MPLS ||
1252 #endif
1253                 ipproto == 0;
1254 }
1255
1256 static int
1257 __ipip6_tunnel_ioctl_validate(struct net *net, struct ip_tunnel_parm_kern *p)
1258 {
1259         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1260                 return -EPERM;
1261
1262         if (!ipip6_valid_ip_proto(p->iph.protocol))
1263                 return -EINVAL;
1264         if (p->iph.version != 4 ||
1265             p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
1266                 return -EINVAL;
1267
1268         if (p->iph.ttl)
1269                 p->iph.frag_off |= htons(IP_DF);
1270         return 0;
1271 }
1272
1273 static int
1274 ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1275 {
1276         struct ip_tunnel *t = netdev_priv(dev);
1277
1278         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
1279                 t = ipip6_tunnel_locate(t->net, p, 0);
1280         if (!t)
1281                 t = netdev_priv(dev);
1282         memcpy(p, &t->parms, sizeof(*p));
1283         return 0;
1284 }
1285
1286 static int
1287 ipip6_tunnel_add(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1288 {
1289         struct ip_tunnel *t = netdev_priv(dev);
1290         int err;
1291
1292         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1293         if (err)
1294                 return err;
1295
1296         t = ipip6_tunnel_locate(t->net, p, 1);
1297         if (!t)
1298                 return -ENOBUFS;
1299         return 0;
1300 }
1301
1302 static int
1303 ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1304 {
1305         struct ip_tunnel *t = netdev_priv(dev);
1306         int err;
1307
1308         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1309         if (err)
1310                 return err;
1311
1312         t = ipip6_tunnel_locate(t->net, p, 0);
1313         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1314                 if (!t)
1315                         return -ENOENT;
1316         } else {
1317                 if (t) {
1318                         if (t->dev != dev)
1319                                 return -EEXIST;
1320                 } else {
1321                         if (((dev->flags & IFF_POINTOPOINT) && !p->iph.daddr) ||
1322                             (!(dev->flags & IFF_POINTOPOINT) && p->iph.daddr))
1323                                 return -EINVAL;
1324                         t = netdev_priv(dev);
1325                 }
1326
1327                 ipip6_tunnel_update(t, p, t->fwmark);
1328         }
1329
1330         return 0;
1331 }
1332
1333 static int
1334 ipip6_tunnel_del(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1335 {
1336         struct ip_tunnel *t = netdev_priv(dev);
1337
1338         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1339                 return -EPERM;
1340
1341         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1342                 t = ipip6_tunnel_locate(t->net, p, 0);
1343                 if (!t)
1344                         return -ENOENT;
1345                 if (t == netdev_priv(dev_to_sit_net(dev)->fb_tunnel_dev))
1346                         return -EPERM;
1347                 dev = t->dev;
1348         }
1349         unregister_netdevice(dev);
1350         return 0;
1351 }
1352
1353 static int
1354 ipip6_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm_kern *p,
1355                  int cmd)
1356 {
1357         switch (cmd) {
1358         case SIOCGETTUNNEL:
1359                 return ipip6_tunnel_get(dev, p);
1360         case SIOCADDTUNNEL:
1361                 return ipip6_tunnel_add(dev, p);
1362         case SIOCCHGTUNNEL:
1363                 return ipip6_tunnel_change(dev, p);
1364         case SIOCDELTUNNEL:
1365                 return ipip6_tunnel_del(dev, p);
1366         default:
1367                 return -EINVAL;
1368         }
1369 }
1370
1371 static int
1372 ipip6_tunnel_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1373                             void __user *data, int cmd)
1374 {
1375         switch (cmd) {
1376         case SIOCGETTUNNEL:
1377         case SIOCADDTUNNEL:
1378         case SIOCCHGTUNNEL:
1379         case SIOCDELTUNNEL:
1380                 return ip_tunnel_siocdevprivate(dev, ifr, data, cmd);
1381         case SIOCGETPRL:
1382                 return ipip6_tunnel_get_prl(dev, data);
1383         case SIOCADDPRL:
1384         case SIOCDELPRL:
1385         case SIOCCHGPRL:
1386                 return ipip6_tunnel_prl_ctl(dev, data, cmd);
1387 #ifdef CONFIG_IPV6_SIT_6RD
1388         case SIOCGET6RD:
1389                 return ipip6_tunnel_get6rd(dev, data);
1390         case SIOCADD6RD:
1391         case SIOCCHG6RD:
1392         case SIOCDEL6RD:
1393                 return ipip6_tunnel_6rdctl(dev, data, cmd);
1394 #endif
1395         default:
1396                 return -EINVAL;
1397         }
1398 }
1399
1400 static const struct net_device_ops ipip6_netdev_ops = {
1401         .ndo_init       = ipip6_tunnel_init,
1402         .ndo_uninit     = ipip6_tunnel_uninit,
1403         .ndo_start_xmit = sit_tunnel_xmit,
1404         .ndo_siocdevprivate = ipip6_tunnel_siocdevprivate,
1405         .ndo_get_iflink = ip_tunnel_get_iflink,
1406         .ndo_tunnel_ctl = ipip6_tunnel_ctl,
1407 };
1408
1409 static void ipip6_dev_free(struct net_device *dev)
1410 {
1411         struct ip_tunnel *tunnel = netdev_priv(dev);
1412
1413         dst_cache_destroy(&tunnel->dst_cache);
1414 }
1415
1416 #define SIT_FEATURES (NETIF_F_SG           | \
1417                       NETIF_F_FRAGLIST     | \
1418                       NETIF_F_HIGHDMA      | \
1419                       NETIF_F_GSO_SOFTWARE | \
1420                       NETIF_F_HW_CSUM)
1421
1422 static void ipip6_tunnel_setup(struct net_device *dev)
1423 {
1424         struct ip_tunnel *tunnel = netdev_priv(dev);
1425         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1426
1427         dev->netdev_ops         = &ipip6_netdev_ops;
1428         dev->header_ops         = &ip_tunnel_header_ops;
1429         dev->needs_free_netdev  = true;
1430         dev->priv_destructor    = ipip6_dev_free;
1431
1432         dev->type               = ARPHRD_SIT;
1433         dev->mtu                = ETH_DATA_LEN - t_hlen;
1434         dev->min_mtu            = IPV6_MIN_MTU;
1435         dev->max_mtu            = IP6_MAX_MTU - t_hlen;
1436         dev->flags              = IFF_NOARP;
1437         netif_keep_dst(dev);
1438         dev->addr_len           = 4;
1439         dev->lltx               = true;
1440         dev->features           |= SIT_FEATURES;
1441         dev->hw_features        |= SIT_FEATURES;
1442         dev->pcpu_stat_type     = NETDEV_PCPU_STAT_TSTATS;
1443
1444 }
1445
1446 static int ipip6_tunnel_init(struct net_device *dev)
1447 {
1448         struct ip_tunnel *tunnel = netdev_priv(dev);
1449         int err;
1450
1451         tunnel->dev = dev;
1452         tunnel->net = dev_net(dev);
1453         strcpy(tunnel->parms.name, dev->name);
1454
1455         ipip6_tunnel_bind_dev(dev);
1456
1457         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1458         if (err)
1459                 return err;
1460
1461         netdev_hold(dev, &tunnel->dev_tracker, GFP_KERNEL);
1462         netdev_lockdep_set_classes(dev);
1463         return 0;
1464 }
1465
1466 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1467 {
1468         struct ip_tunnel *tunnel = netdev_priv(dev);
1469         struct iphdr *iph = &tunnel->parms.iph;
1470         struct net *net = dev_net(dev);
1471         struct sit_net *sitn = net_generic(net, sit_net_id);
1472
1473         iph->version            = 4;
1474         iph->protocol           = IPPROTO_IPV6;
1475         iph->ihl                = 5;
1476         iph->ttl                = 64;
1477
1478         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1479 }
1480
1481 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1482                           struct netlink_ext_ack *extack)
1483 {
1484         u8 proto;
1485
1486         if (!data || !data[IFLA_IPTUN_PROTO])
1487                 return 0;
1488
1489         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1490         if (!ipip6_valid_ip_proto(proto))
1491                 return -EINVAL;
1492
1493         return 0;
1494 }
1495
1496 static void ipip6_netlink_parms(struct nlattr *data[],
1497                                 struct ip_tunnel_parm_kern *parms,
1498                                 __u32 *fwmark)
1499 {
1500         memset(parms, 0, sizeof(*parms));
1501
1502         parms->iph.version = 4;
1503         parms->iph.protocol = IPPROTO_IPV6;
1504         parms->iph.ihl = 5;
1505         parms->iph.ttl = 64;
1506
1507         if (!data)
1508                 return;
1509
1510         ip_tunnel_netlink_parms(data, parms);
1511
1512         if (data[IFLA_IPTUN_FWMARK])
1513                 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1514 }
1515
1516 #ifdef CONFIG_IPV6_SIT_6RD
1517 /* This function returns true when 6RD attributes are present in the nl msg */
1518 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1519                                     struct ip_tunnel_6rd *ip6rd)
1520 {
1521         bool ret = false;
1522         memset(ip6rd, 0, sizeof(*ip6rd));
1523
1524         if (!data)
1525                 return ret;
1526
1527         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1528                 ret = true;
1529                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1530         }
1531
1532         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1533                 ret = true;
1534                 ip6rd->relay_prefix =
1535                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1536         }
1537
1538         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1539                 ret = true;
1540                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1541         }
1542
1543         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1544                 ret = true;
1545                 ip6rd->relay_prefixlen =
1546                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1547         }
1548
1549         return ret;
1550 }
1551 #endif
1552
1553 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1554                          struct nlattr *tb[], struct nlattr *data[],
1555                          struct netlink_ext_ack *extack)
1556 {
1557         struct net *net = dev_net(dev);
1558         struct ip_tunnel *nt;
1559         struct ip_tunnel_encap ipencap;
1560 #ifdef CONFIG_IPV6_SIT_6RD
1561         struct ip_tunnel_6rd ip6rd;
1562 #endif
1563         int err;
1564
1565         nt = netdev_priv(dev);
1566
1567         if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
1568                 err = ip_tunnel_encap_setup(nt, &ipencap);
1569                 if (err < 0)
1570                         return err;
1571         }
1572
1573         ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1574
1575         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1576                 return -EEXIST;
1577
1578         err = ipip6_tunnel_create(dev);
1579         if (err < 0)
1580                 return err;
1581
1582         if (tb[IFLA_MTU]) {
1583                 u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1584
1585                 if (mtu >= IPV6_MIN_MTU &&
1586                     mtu <= IP6_MAX_MTU - dev->hard_header_len)
1587                         dev->mtu = mtu;
1588         }
1589
1590 #ifdef CONFIG_IPV6_SIT_6RD
1591         if (ipip6_netlink_6rd_parms(data, &ip6rd)) {
1592                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1593                 if (err < 0)
1594                         unregister_netdevice_queue(dev, NULL);
1595         }
1596 #endif
1597
1598         return err;
1599 }
1600
1601 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1602                             struct nlattr *data[],
1603                             struct netlink_ext_ack *extack)
1604 {
1605         struct ip_tunnel *t = netdev_priv(dev);
1606         struct ip_tunnel_encap ipencap;
1607         struct ip_tunnel_parm_kern p;
1608         struct net *net = t->net;
1609         struct sit_net *sitn = net_generic(net, sit_net_id);
1610 #ifdef CONFIG_IPV6_SIT_6RD
1611         struct ip_tunnel_6rd ip6rd;
1612 #endif
1613         __u32 fwmark = t->fwmark;
1614         int err;
1615
1616         if (dev == sitn->fb_tunnel_dev)
1617                 return -EINVAL;
1618
1619         if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
1620                 err = ip_tunnel_encap_setup(t, &ipencap);
1621                 if (err < 0)
1622                         return err;
1623         }
1624
1625         ipip6_netlink_parms(data, &p, &fwmark);
1626
1627         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1628             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1629                 return -EINVAL;
1630
1631         t = ipip6_tunnel_locate(net, &p, 0);
1632
1633         if (t) {
1634                 if (t->dev != dev)
1635                         return -EEXIST;
1636         } else
1637                 t = netdev_priv(dev);
1638
1639         ipip6_tunnel_update(t, &p, fwmark);
1640
1641 #ifdef CONFIG_IPV6_SIT_6RD
1642         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1643                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1644 #endif
1645
1646         return 0;
1647 }
1648
1649 static size_t ipip6_get_size(const struct net_device *dev)
1650 {
1651         return
1652                 /* IFLA_IPTUN_LINK */
1653                 nla_total_size(4) +
1654                 /* IFLA_IPTUN_LOCAL */
1655                 nla_total_size(4) +
1656                 /* IFLA_IPTUN_REMOTE */
1657                 nla_total_size(4) +
1658                 /* IFLA_IPTUN_TTL */
1659                 nla_total_size(1) +
1660                 /* IFLA_IPTUN_TOS */
1661                 nla_total_size(1) +
1662                 /* IFLA_IPTUN_PMTUDISC */
1663                 nla_total_size(1) +
1664                 /* IFLA_IPTUN_FLAGS */
1665                 nla_total_size(2) +
1666                 /* IFLA_IPTUN_PROTO */
1667                 nla_total_size(1) +
1668 #ifdef CONFIG_IPV6_SIT_6RD
1669                 /* IFLA_IPTUN_6RD_PREFIX */
1670                 nla_total_size(sizeof(struct in6_addr)) +
1671                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1672                 nla_total_size(4) +
1673                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1674                 nla_total_size(2) +
1675                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1676                 nla_total_size(2) +
1677 #endif
1678                 /* IFLA_IPTUN_ENCAP_TYPE */
1679                 nla_total_size(2) +
1680                 /* IFLA_IPTUN_ENCAP_FLAGS */
1681                 nla_total_size(2) +
1682                 /* IFLA_IPTUN_ENCAP_SPORT */
1683                 nla_total_size(2) +
1684                 /* IFLA_IPTUN_ENCAP_DPORT */
1685                 nla_total_size(2) +
1686                 /* IFLA_IPTUN_FWMARK */
1687                 nla_total_size(4) +
1688                 0;
1689 }
1690
1691 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1692 {
1693         struct ip_tunnel *tunnel = netdev_priv(dev);
1694         struct ip_tunnel_parm_kern *parm = &tunnel->parms;
1695
1696         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1697             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1698             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1699             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1700             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1701             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1702                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1703             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1704             nla_put_be16(skb, IFLA_IPTUN_FLAGS,
1705                          ip_tunnel_flags_to_be16(parm->i_flags)) ||
1706             nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1707                 goto nla_put_failure;
1708
1709 #ifdef CONFIG_IPV6_SIT_6RD
1710         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1711                              &tunnel->ip6rd.prefix) ||
1712             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1713                             tunnel->ip6rd.relay_prefix) ||
1714             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1715                         tunnel->ip6rd.prefixlen) ||
1716             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1717                         tunnel->ip6rd.relay_prefixlen))
1718                 goto nla_put_failure;
1719 #endif
1720
1721         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1722                         tunnel->encap.type) ||
1723             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1724                         tunnel->encap.sport) ||
1725             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1726                         tunnel->encap.dport) ||
1727             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1728                         tunnel->encap.flags))
1729                 goto nla_put_failure;
1730
1731         return 0;
1732
1733 nla_put_failure:
1734         return -EMSGSIZE;
1735 }
1736
1737 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1738         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1739         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1740         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1741         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1742         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1743         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1744         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1745         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1746 #ifdef CONFIG_IPV6_SIT_6RD
1747         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1748         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1749         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1750         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1751 #endif
1752         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1753         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1754         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1755         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1756         [IFLA_IPTUN_FWMARK]             = { .type = NLA_U32 },
1757 };
1758
1759 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1760 {
1761         struct net *net = dev_net(dev);
1762         struct sit_net *sitn = net_generic(net, sit_net_id);
1763
1764         if (dev != sitn->fb_tunnel_dev)
1765                 unregister_netdevice_queue(dev, head);
1766 }
1767
1768 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1769         .kind           = "sit",
1770         .maxtype        = IFLA_IPTUN_MAX,
1771         .policy         = ipip6_policy,
1772         .priv_size      = sizeof(struct ip_tunnel),
1773         .setup          = ipip6_tunnel_setup,
1774         .validate       = ipip6_validate,
1775         .newlink        = ipip6_newlink,
1776         .changelink     = ipip6_changelink,
1777         .get_size       = ipip6_get_size,
1778         .fill_info      = ipip6_fill_info,
1779         .dellink        = ipip6_dellink,
1780         .get_link_net   = ip_tunnel_get_link_net,
1781 };
1782
1783 static struct xfrm_tunnel sit_handler __read_mostly = {
1784         .handler        =       ipip6_rcv,
1785         .err_handler    =       ipip6_err,
1786         .priority       =       1,
1787 };
1788
1789 static struct xfrm_tunnel ipip_handler __read_mostly = {
1790         .handler        =       ipip_rcv,
1791         .err_handler    =       ipip6_err,
1792         .priority       =       2,
1793 };
1794
1795 #if IS_ENABLED(CONFIG_MPLS)
1796 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1797         .handler        =       mplsip_rcv,
1798         .err_handler    =       ipip6_err,
1799         .priority       =       2,
1800 };
1801 #endif
1802
1803 static void __net_exit sit_destroy_tunnels(struct net *net,
1804                                            struct list_head *head)
1805 {
1806         struct sit_net *sitn = net_generic(net, sit_net_id);
1807         struct net_device *dev, *aux;
1808         int prio;
1809
1810         for_each_netdev_safe(net, dev, aux)
1811                 if (dev->rtnl_link_ops == &sit_link_ops)
1812                         unregister_netdevice_queue(dev, head);
1813
1814         for (prio = 0; prio < 4; prio++) {
1815                 int h;
1816                 for (h = 0; h < (prio ? IP6_SIT_HASH_SIZE : 1); h++) {
1817                         struct ip_tunnel *t;
1818
1819                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1820                         while (t) {
1821                                 /* If dev is in the same netns, it has already
1822                                  * been added to the list by the previous loop.
1823                                  */
1824                                 if (!net_eq(dev_net(t->dev), net))
1825                                         unregister_netdevice_queue(t->dev,
1826                                                                    head);
1827                                 t = rtnl_dereference(t->next);
1828                         }
1829                 }
1830         }
1831 }
1832
1833 static int __net_init sit_init_net(struct net *net)
1834 {
1835         struct sit_net *sitn = net_generic(net, sit_net_id);
1836         struct ip_tunnel *t;
1837         int err;
1838
1839         sitn->tunnels[0] = sitn->tunnels_wc;
1840         sitn->tunnels[1] = sitn->tunnels_l;
1841         sitn->tunnels[2] = sitn->tunnels_r;
1842         sitn->tunnels[3] = sitn->tunnels_r_l;
1843
1844         if (!net_has_fallback_tunnels(net))
1845                 return 0;
1846
1847         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1848                                            NET_NAME_UNKNOWN,
1849                                            ipip6_tunnel_setup);
1850         if (!sitn->fb_tunnel_dev) {
1851                 err = -ENOMEM;
1852                 goto err_alloc_dev;
1853         }
1854         dev_net_set(sitn->fb_tunnel_dev, net);
1855         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1856         /* FB netdevice is special: we have one, and only one per netns.
1857          * Allowing to move it to another netns is clearly unsafe.
1858          */
1859         sitn->fb_tunnel_dev->netns_local = true;
1860
1861         err = register_netdev(sitn->fb_tunnel_dev);
1862         if (err)
1863                 goto err_reg_dev;
1864
1865         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1866         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1867
1868         t = netdev_priv(sitn->fb_tunnel_dev);
1869
1870         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1871         return 0;
1872
1873 err_reg_dev:
1874         free_netdev(sitn->fb_tunnel_dev);
1875 err_alloc_dev:
1876         return err;
1877 }
1878
1879 static void __net_exit sit_exit_batch_rtnl(struct list_head *net_list,
1880                                            struct list_head *dev_to_kill)
1881 {
1882         struct net *net;
1883
1884         ASSERT_RTNL();
1885         list_for_each_entry(net, net_list, exit_list)
1886                 sit_destroy_tunnels(net, dev_to_kill);
1887 }
1888
1889 static struct pernet_operations sit_net_ops = {
1890         .init = sit_init_net,
1891         .exit_batch_rtnl = sit_exit_batch_rtnl,
1892         .id   = &sit_net_id,
1893         .size = sizeof(struct sit_net),
1894 };
1895
1896 static void __exit sit_cleanup(void)
1897 {
1898         rtnl_link_unregister(&sit_link_ops);
1899         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1900         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1901 #if IS_ENABLED(CONFIG_MPLS)
1902         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1903 #endif
1904
1905         unregister_pernet_device(&sit_net_ops);
1906         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1907 }
1908
1909 static int __init sit_init(void)
1910 {
1911         int err;
1912
1913         pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1914
1915         err = register_pernet_device(&sit_net_ops);
1916         if (err < 0)
1917                 return err;
1918         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1919         if (err < 0) {
1920                 pr_info("%s: can't register ip6ip4\n", __func__);
1921                 goto xfrm_tunnel_failed;
1922         }
1923         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1924         if (err < 0) {
1925                 pr_info("%s: can't register ip4ip4\n", __func__);
1926                 goto xfrm_tunnel4_failed;
1927         }
1928 #if IS_ENABLED(CONFIG_MPLS)
1929         err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1930         if (err < 0) {
1931                 pr_info("%s: can't register mplsip\n", __func__);
1932                 goto xfrm_tunnel_mpls_failed;
1933         }
1934 #endif
1935         err = rtnl_link_register(&sit_link_ops);
1936         if (err < 0)
1937                 goto rtnl_link_failed;
1938
1939 out:
1940         return err;
1941
1942 rtnl_link_failed:
1943 #if IS_ENABLED(CONFIG_MPLS)
1944         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1945 xfrm_tunnel_mpls_failed:
1946 #endif
1947         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1948 xfrm_tunnel4_failed:
1949         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1950 xfrm_tunnel_failed:
1951         unregister_pernet_device(&sit_net_ops);
1952         goto out;
1953 }
1954
1955 module_init(sit_init);
1956 module_exit(sit_cleanup);
1957 MODULE_DESCRIPTION("IPv6-in-IPv4 tunnel SIT driver");
1958 MODULE_LICENSE("GPL");
1959 MODULE_ALIAS_RTNL_LINK("sit");
1960 MODULE_ALIAS_NETDEV("sit0");