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             <[email protected]>
   7  *      Alexey Kuznetsov        <[email protected]>
   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 <[email protected]>:       6to4 support
  16  * Nate Thompson <[email protected]>:             6to4 support
  17  * Fred Templin <[email protected]>:    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,
  95                                              __be32 remote, __be32 local,
  96                                              int sifindex)
  97 {
  98         unsigned int h0 = HASH(remote);
  99         unsigned int h1 = HASH(local);
 100         struct ip_tunnel *t;
 101         struct sit_net *sitn = net_generic(net, sit_net_id);
 102         int ifindex = dev ? dev->ifindex : 0;
 103
 104         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 105                 if (local == t->parms.iph.saddr &&
 106                     remote == t->parms.iph.daddr &&
 107                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 108                      sifindex == t->parms.link) &&
 109                     (t->dev->flags & IFF_UP))
 110                         return t;
 111         }
 112         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 113                 if (remote == t->parms.iph.daddr &&
 114                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 115                      sifindex == t->parms.link) &&
 116                     (t->dev->flags & IFF_UP))
 117                         return t;
 118         }
 119         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 120                 if (local == t->parms.iph.saddr &&
 121                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 122                      sifindex == t->parms.link) &&
 123                     (t->dev->flags & IFF_UP))
 124                         return t;
 125         }
 126         t = rcu_dereference(sitn->tunnels_wc[0]);
 127         if (t && (t->dev->flags & IFF_UP))
 128                 return t;
 129         return NULL;
 130 }
 131
 132 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 133                 struct ip_tunnel_parm *parms)
 134 {
 135         __be32 remote = parms->iph.daddr;
 136         __be32 local = parms->iph.saddr;
 137         unsigned int h = 0;
 138         int prio = 0;
 139
 140         if (remote) {
 141                 prio |= 2;
 142                 h ^= HASH(remote);
 143         }
 144         if (local) {
 145                 prio |= 1;
 146                 h ^= HASH(local);
 147         }
 148         return &sitn->tunnels[prio][h];
 149 }
 150
 151 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 152                 struct ip_tunnel *t)
 153 {
 154         return __ipip6_bucket(sitn, &t->parms);
 155 }
 156
 157 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 158 {
 159         struct ip_tunnel __rcu **tp;
 160         struct ip_tunnel *iter;
 161
 162         for (tp = ipip6_bucket(sitn, t);
 163              (iter = rtnl_dereference(*tp)) != NULL;
 164              tp = &iter->next) {
 165                 if (t == iter) {
 166                         rcu_assign_pointer(*tp, t->next);
 167                         break;
 168                 }
 169         }
 170 }
 171
 172 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 173 {
 174         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 175
 176         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 177         rcu_assign_pointer(*tp, t);
 178 }
 179
 180 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 181 {
 182 #ifdef CONFIG_IPV6_SIT_6RD
 183         struct ip_tunnel *t = netdev_priv(dev);
 184
 185         if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
 186                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 187                 t->ip6rd.relay_prefix = 0;
 188                 t->ip6rd.prefixlen = 16;
 189                 t->ip6rd.relay_prefixlen = 0;
 190         } else {
 191                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 192                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 193         }
 194 #endif
 195 }
 196
 197 static int ipip6_tunnel_create(struct net_device *dev)
 198 {
 199         struct ip_tunnel *t = netdev_priv(dev);
 200         struct net *net = dev_net(dev);
 201         struct sit_net *sitn = net_generic(net, sit_net_id);
 202         int err;
 203
 204         memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 205         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 206
 207         if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 208                 dev->priv_flags |= IFF_ISATAP;
 209
 210         dev->rtnl_link_ops = &sit_link_ops;
 211
 212         err = register_netdevice(dev);
 213         if (err < 0)
 214                 goto out;
 215
 216         ipip6_tunnel_clone_6rd(dev, sitn);
 217
 218         dev_hold(dev);
 219
 220         ipip6_tunnel_link(sitn, t);
 221         return 0;
 222
 223 out:
 224         return err;
 225 }
 226
 227 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 228                 struct ip_tunnel_parm *parms, int create)
 229 {
 230         __be32 remote = parms->iph.daddr;
 231         __be32 local = parms->iph.saddr;
 232         struct ip_tunnel *t, *nt;
 233         struct ip_tunnel __rcu **tp;
 234         struct net_device *dev;
 235         char name[IFNAMSIZ];
 236         struct sit_net *sitn = net_generic(net, sit_net_id);
 237
 238         for (tp = __ipip6_bucket(sitn, parms);
 239             (t = rtnl_dereference(*tp)) != NULL;
 240              tp = &t->next) {
 241                 if (local == t->parms.iph.saddr &&
 242                     remote == t->parms.iph.daddr &&
 243                     parms->link == t->parms.link) {
 244                         if (create)
 245                                 return NULL;
 246                         else
 247                                 return t;
 248                 }
 249         }
 250         if (!create)
 251                 goto failed;
 252
 253         if (parms->name[0]) {
 254                 if (!dev_valid_name(parms->name))
 255                         goto failed;
 256                 strlcpy(name, parms->name, IFNAMSIZ);
 257         } else {
 258                 strcpy(name, "sit%d");
 259         }
 260         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 261                            ipip6_tunnel_setup);
 262         if (!dev)
 263                 return NULL;
 264
 265         dev_net_set(dev, net);
 266
 267         nt = netdev_priv(dev);
 268
 269         nt->parms = *parms;
 270         if (ipip6_tunnel_create(dev) < 0)
 271                 goto failed_free;
 272
 273         return nt;
 274
 275 failed_free:
 276         free_netdev(dev);
 277 failed:
 278         return NULL;
 279 }
 280
 281 #define for_each_prl_rcu(start)                 \
 282         for (prl = rcu_dereference(start);      \
 283              prl;                               \
 284              prl = rcu_dereference(prl->next))
 285
 286 static struct ip_tunnel_prl_entry *
 287 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 288 {
 289         struct ip_tunnel_prl_entry *prl;
 290
 291         for_each_prl_rcu(t->prl)
 292                 if (prl->addr == addr)
 293                         break;
 294         return prl;
 295
 296 }
 297
 298 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 299                                 struct ip_tunnel_prl __user *a)
 300 {
 301         struct ip_tunnel_prl kprl, *kp;
 302         struct ip_tunnel_prl_entry *prl;
 303         unsigned int cmax, c = 0, ca, len;
 304         int ret = 0;
 305
 306         if (copy_from_user(&kprl, a, sizeof(kprl)))
 307                 return -EFAULT;
 308         cmax = kprl.datalen / sizeof(kprl);
 309         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 310                 cmax = 1;
 311
 312         /* For simple GET or for root users,
 313          * we try harder to allocate.
 314          */
 315         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 316                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
 317                 NULL;
 318
 319         rcu_read_lock();
 320
 321         ca = t->prl_count < cmax ? t->prl_count : cmax;
 322
 323         if (!kp) {
 324                 /* We don't try hard to allocate much memory for
 325                  * non-root users.
 326                  * For root users, retry allocating enough memory for
 327                  * the answer.
 328                  */
 329                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 330                 if (!kp) {
 331                         ret = -ENOMEM;
 332                         goto out;
 333                 }
 334         }
 335
 336         c = 0;
 337         for_each_prl_rcu(t->prl) {
 338                 if (c >= cmax)
 339                         break;
 340                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 341                         continue;
 342                 kp[c].addr = prl->addr;
 343                 kp[c].flags = prl->flags;
 344                 c++;
 345                 if (kprl.addr != htonl(INADDR_ANY))
 346                         break;
 347         }
 348 out:
 349         rcu_read_unlock();
 350
 351         len = sizeof(*kp) * c;
 352         ret = 0;
 353         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 354                 ret = -EFAULT;
 355
 356         kfree(kp);
 357
 358         return ret;
 359 }
 360
 361 static int
 362 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 363 {
 364         struct ip_tunnel_prl_entry *p;
 365         int err = 0;
 366
 367         if (a->addr == htonl(INADDR_ANY))
 368                 return -EINVAL;
 369
 370         ASSERT_RTNL();
 371
 372         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 373                 if (p->addr == a->addr) {
 374                         if (chg) {
 375                                 p->flags = a->flags;
 376                                 goto out;
 377                         }
 378                         err = -EEXIST;
 379                         goto out;
 380                 }
 381         }
 382
 383         if (chg) {
 384                 err = -ENXIO;
 385                 goto out;
 386         }
 387
 388         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 389         if (!p) {
 390                 err = -ENOBUFS;
 391                 goto out;
 392         }
 393
 394         p->next = t->prl;
 395         p->addr = a->addr;
 396         p->flags = a->flags;
 397         t->prl_count++;
 398         rcu_assign_pointer(t->prl, p);
 399 out:
 400         return err;
 401 }
 402
 403 static void prl_list_destroy_rcu(struct rcu_head *head)
 404 {
 405         struct ip_tunnel_prl_entry *p, *n;
 406
 407         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 408         do {
 409                 n = rcu_dereference_protected(p->next, 1);
 410                 kfree(p);
 411                 p = n;
 412         } while (p);
 413 }
 414
 415 static int
 416 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 417 {
 418         struct ip_tunnel_prl_entry *x;
 419         struct ip_tunnel_prl_entry __rcu **p;
 420         int err = 0;
 421
 422         ASSERT_RTNL();
 423
 424         if (a && a->addr != htonl(INADDR_ANY)) {
 425                 for (p = &t->prl;
 426                      (x = rtnl_dereference(*p)) != NULL;
 427                      p = &x->next) {
 428                         if (x->addr == a->addr) {
 429                                 *p = x->next;
 430                                 kfree_rcu(x, rcu_head);
 431                                 t->prl_count--;
 432                                 goto out;
 433                         }
 434                 }
 435                 err = -ENXIO;
 436         } else {
 437                 x = rtnl_dereference(t->prl);
 438                 if (x) {
 439                         t->prl_count = 0;
 440                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 441                         t->prl = NULL;
 442                 }
 443         }
 444 out:
 445         return err;
 446 }
 447
 448 static int
 449 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 450 {
 451         struct ip_tunnel_prl_entry *p;
 452         int ok = 1;
 453
 454         rcu_read_lock();
 455         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 456         if (p) {
 457                 if (p->flags & PRL_DEFAULT)
 458                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 459                 else
 460                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 461         } else {
 462                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 463
 464                 if (ipv6_addr_is_isatap(addr6) &&
 465                     (addr6->s6_addr32[3] == iph->saddr) &&
 466                     ipv6_chk_prefix(addr6, t->dev))
 467                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 468                 else
 469                         ok = 0;
 470         }
 471         rcu_read_unlock();
 472         return ok;
 473 }
 474
 475 static void ipip6_tunnel_uninit(struct net_device *dev)
 476 {
 477         struct ip_tunnel *tunnel = netdev_priv(dev);
 478         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 479
 480         if (dev == sitn->fb_tunnel_dev) {
 481                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 482         } else {
 483                 ipip6_tunnel_unlink(sitn, tunnel);
 484                 ipip6_tunnel_del_prl(tunnel, NULL);
 485         }
 486         dst_cache_reset(&tunnel->dst_cache);
 487         dev_put(dev);
 488 }
 489
 490 static int ipip6_err(struct sk_buff *skb, u32 info)
 491 {
 492         const struct iphdr *iph = (const struct iphdr *)skb->data;
 493         const int type = icmp_hdr(skb)->type;
 494         const int code = icmp_hdr(skb)->code;
 495         unsigned int data_len = 0;
 496         struct ip_tunnel *t;
 497         int sifindex;
 498         int err;
 499
 500         switch (type) {
 501         default:
 502         case ICMP_PARAMETERPROB:
 503                 return 0;
 504
 505         case ICMP_DEST_UNREACH:
 506                 switch (code) {
 507                 case ICMP_SR_FAILED:
 508                         /* Impossible event. */
 509                         return 0;
 510                 default:
 511                         /* All others are translated to HOST_UNREACH.
 512                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 513                            I believe they are just ether pollution. --ANK
 514                          */
 515                         break;
 516                 }
 517                 break;
 518         case ICMP_TIME_EXCEEDED:
 519                 if (code != ICMP_EXC_TTL)
 520                         return 0;
 521                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 522                 break;
 523         case ICMP_REDIRECT:
 524                 break;
 525         }
 526
 527         err = -ENOENT;
 528
 529         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 530         t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 531                                 iph->daddr, iph->saddr, sifindex);
 532         if (!t)
 533                 goto out;
 534
 535         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 536                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 537                                  t->parms.link, 0, iph->protocol, 0);
 538                 err = 0;
 539                 goto out;
 540         }
 541         if (type == ICMP_REDIRECT) {
 542                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
 543                               iph->protocol, 0);
 544                 err = 0;
 545                 goto out;
 546         }
 547
 548         err = 0;
 549         if (!ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 550                 goto out;
 551
 552         if (t->parms.iph.daddr == 0)
 553                 goto out;
 554
 555         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 556                 goto out;
 557
 558         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 559                 t->err_count++;
 560         else
 561                 t->err_count = 1;
 562         t->err_time = jiffies;
 563 out:
 564         return err;
 565 }
 566
 567 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 568                                   const struct in6_addr *v6addr)
 569 {
 570         __be32 v4embed = 0;
 571         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 572                 return true;
 573         return false;
 574 }
 575
 576 /* Checks if an address matches an address on the tunnel interface.
 577  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 578  * Long story:
 579  * This function is called after we considered the packet as spoofed
 580  * in is_spoofed_6rd.
 581  * We may have a router that is doing NAT for proto 41 packets
 582  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 583  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 584  * function will return true, dropping the packet.
 585  * But, we can still check if is spoofed against the IP
 586  * addresses associated with the interface.
 587  */
 588 static bool only_dnatted(const struct ip_tunnel *tunnel,
 589         const struct in6_addr *v6dst)
 590 {
 591         int prefix_len;
 592
 593 #ifdef CONFIG_IPV6_SIT_6RD
 594         prefix_len = tunnel->ip6rd.prefixlen + 32
 595                 - tunnel->ip6rd.relay_prefixlen;
 596 #else
 597         prefix_len = 48;
 598 #endif
 599         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 600 }
 601
 602 /* Returns true if a packet is spoofed */
 603 static bool packet_is_spoofed(struct sk_buff *skb,
 604                               const struct iphdr *iph,
 605                               struct ip_tunnel *tunnel)
 606 {
 607         const struct ipv6hdr *ipv6h;
 608
 609         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 610                 if (!isatap_chksrc(skb, iph, tunnel))
 611                         return true;
 612
 613                 return false;
 614         }
 615
 616         if (tunnel->dev->flags & IFF_POINTOPOINT)
 617                 return false;
 618
 619         ipv6h = ipv6_hdr(skb);
 620
 621         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 622                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 623                                      &iph->saddr, &ipv6h->saddr,
 624                                      &iph->daddr, &ipv6h->daddr);
 625                 return true;
 626         }
 627
 628         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 629                 return false;
 630
 631         if (only_dnatted(tunnel, &ipv6h->daddr))
 632                 return false;
 633
 634         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 635                              &iph->saddr, &ipv6h->saddr,
 636                              &iph->daddr, &ipv6h->daddr);
 637         return true;
 638 }
 639
 640 static int ipip6_rcv(struct sk_buff *skb)
 641 {
 642         const struct iphdr *iph = ip_hdr(skb);
 643         struct ip_tunnel *tunnel;
 644         int sifindex;
 645         int err;
 646
 647         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 648         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 649                                      iph->saddr, iph->daddr, sifindex);
 650         if (tunnel) {
 651                 struct pcpu_sw_netstats *tstats;
 652
 653                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 654                     tunnel->parms.iph.protocol != 0)
 655                         goto out;
 656
 657                 skb->mac_header = skb->network_header;
 658                 skb_reset_network_header(skb);
 659                 IPCB(skb)->flags = 0;
 660                 skb->dev = tunnel->dev;
 661
 662                 if (packet_is_spoofed(skb, iph, tunnel)) {
 663                         tunnel->dev->stats.rx_errors++;
 664                         goto out;
 665                 }
 666
 667                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 668                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
 669                         goto out;
 670
 671                 err = IP_ECN_decapsulate(iph, skb);
 672                 if (unlikely(err)) {
 673                         if (log_ecn_error)
 674                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 675                                                      &iph->saddr, iph->tos);
 676                         if (err > 1) {
 677                                 ++tunnel->dev->stats.rx_frame_errors;
 678                                 ++tunnel->dev->stats.rx_errors;
 679                                 goto out;
 680                         }
 681                 }
 682
 683                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 684                 u64_stats_update_begin(&tstats->syncp);
 685                 tstats->rx_packets++;
 686                 tstats->rx_bytes += skb->len;
 687                 u64_stats_update_end(&tstats->syncp);
 688
 689                 netif_rx(skb);
 690
 691                 return 0;
 692         }
 693
 694         /* no tunnel matched,  let upstream know, ipsec may handle it */
 695         return 1;
 696 out:
 697         kfree_skb(skb);
 698         return 0;
 699 }
 700
 701 static const struct tnl_ptk_info ipip_tpi = {
 702         /* no tunnel info required for ipip. */
 703         .proto = htons(ETH_P_IP),
 704 };
 705
 706 #if IS_ENABLED(CONFIG_MPLS)
 707 static const struct tnl_ptk_info mplsip_tpi = {
 708         /* no tunnel info required for mplsip. */
 709         .proto = htons(ETH_P_MPLS_UC),
 710 };
 711 #endif
 712
 713 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 714 {
 715         const struct iphdr *iph;
 716         struct ip_tunnel *tunnel;
 717         int sifindex;
 718
 719         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 720
 721         iph = ip_hdr(skb);
 722         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 723                                      iph->saddr, iph->daddr, sifindex);
 724         if (tunnel) {
 725                 const struct tnl_ptk_info *tpi;
 726
 727                 if (tunnel->parms.iph.protocol != ipproto &&
 728                     tunnel->parms.iph.protocol != 0)
 729                         goto drop;
 730
 731                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 732                         goto drop;
 733 #if IS_ENABLED(CONFIG_MPLS)
 734                 if (ipproto == IPPROTO_MPLS)
 735                         tpi = &mplsip_tpi;
 736                 else
 737 #endif
 738                         tpi = &ipip_tpi;
 739                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
 740                         goto drop;
 741                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 742         }
 743
 744         return 1;
 745
 746 drop:
 747         kfree_skb(skb);
 748         return 0;
 749 }
 750
 751 static int ipip_rcv(struct sk_buff *skb)
 752 {
 753         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
 754 }
 755
 756 #if IS_ENABLED(CONFIG_MPLS)
 757 static int mplsip_rcv(struct sk_buff *skb)
 758 {
 759         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
 760 }
 761 #endif
 762
 763 /*
 764  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 765  * stores the embedded IPv4 address in v4dst and returns true.
 766  */
 767 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 768                       __be32 *v4dst)
 769 {
 770 #ifdef CONFIG_IPV6_SIT_6RD
 771         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 772                               tunnel->ip6rd.prefixlen)) {
 773                 unsigned int pbw0, pbi0;
 774                 int pbi1;
 775                 u32 d;
 776
 777                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 778                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 779
 780                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 781                     tunnel->ip6rd.relay_prefixlen;
 782
 783                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 784                 if (pbi1 > 0)
 785                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 786                              (32 - pbi1);
 787
 788                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 789                 return true;
 790         }
 791 #else
 792         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 793                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 794                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 795                 return true;
 796         }
 797 #endif
 798         return false;
 799 }
 800
 801 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 802                              const struct in6_addr *v6dst)
 803 {
 804         __be32 dst = 0;
 805         check_6rd(tunnel, v6dst, &dst);
 806         return dst;
 807 }
 808
 809 /*
 810  *      This function assumes it is being called from dev_queue_xmit()
 811  *      and that skb is filled properly by that function.
 812  */
 813
 814 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 815                                      struct net_device *dev)
 816 {
 817         struct ip_tunnel *tunnel = netdev_priv(dev);
 818         const struct iphdr  *tiph = &tunnel->parms.iph;
 819         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 820         u8     tos = tunnel->parms.iph.tos;
 821         __be16 df = tiph->frag_off;
 822         struct rtable *rt;              /* Route to the other host */
 823         struct net_device *tdev;        /* Device to other host */
 824         unsigned int max_headroom;      /* The extra header space needed */
 825         __be32 dst = tiph->daddr;
 826         struct flowi4 fl4;
 827         int    mtu;
 828         const struct in6_addr *addr6;
 829         int addr_type;
 830         u8 ttl;
 831         u8 protocol = IPPROTO_IPV6;
 832         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 833
 834         if (tos == 1)
 835                 tos = ipv6_get_dsfield(iph6);
 836
 837         /* ISATAP (RFC4214) - must come before 6to4 */
 838         if (dev->priv_flags & IFF_ISATAP) {
 839                 struct neighbour *neigh = NULL;
 840                 bool do_tx_error = false;
 841
 842                 if (skb_dst(skb))
 843                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 844
 845                 if (!neigh) {
 846                         net_dbg_ratelimited("nexthop == NULL\n");
 847                         goto tx_error;
 848                 }
 849
 850                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 851                 addr_type = ipv6_addr_type(addr6);
 852
 853                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 854                      ipv6_addr_is_isatap(addr6))
 855                         dst = addr6->s6_addr32[3];
 856                 else
 857                         do_tx_error = true;
 858
 859                 neigh_release(neigh);
 860                 if (do_tx_error)
 861                         goto tx_error;
 862         }
 863
 864         if (!dst)
 865                 dst = try_6rd(tunnel, &iph6->daddr);
 866
 867         if (!dst) {
 868                 struct neighbour *neigh = NULL;
 869                 bool do_tx_error = false;
 870
 871                 if (skb_dst(skb))
 872                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 873
 874                 if (!neigh) {
 875                         net_dbg_ratelimited("nexthop == NULL\n");
 876                         goto tx_error;
 877                 }
 878
 879                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 880                 addr_type = ipv6_addr_type(addr6);
 881
 882                 if (addr_type == IPV6_ADDR_ANY) {
 883                         addr6 = &ipv6_hdr(skb)->daddr;
 884                         addr_type = ipv6_addr_type(addr6);
 885                 }
 886
 887                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 888                         dst = addr6->s6_addr32[3];
 889                 else
 890                         do_tx_error = true;
 891
 892                 neigh_release(neigh);
 893                 if (do_tx_error)
 894                         goto tx_error;
 895         }
 896
 897         flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
 898                            RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
 899                            0, dst, tiph->saddr, 0, 0,
 900                            sock_net_uid(tunnel->net, NULL));
 901         rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
 902
 903         if (IS_ERR(rt)) {
 904                 dev->stats.tx_carrier_errors++;
 905                 goto tx_error_icmp;
 906         }
 907         if (rt->rt_type != RTN_UNICAST) {
 908                 ip_rt_put(rt);
 909                 dev->stats.tx_carrier_errors++;
 910                 goto tx_error_icmp;
 911         }
 912         tdev = rt->dst.dev;
 913
 914         if (tdev == dev) {
 915                 ip_rt_put(rt);
 916                 dev->stats.collisions++;
 917                 goto tx_error;
 918         }
 919
 920         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 921                 ip_rt_put(rt);
 922                 goto tx_error;
 923         }
 924
 925         if (df) {
 926                 mtu = dst_mtu(&rt->dst) - t_hlen;
 927
 928                 if (mtu < 68) {
 929                         dev->stats.collisions++;
 930                         ip_rt_put(rt);
 931                         goto tx_error;
 932                 }
 933
 934                 if (mtu < IPV6_MIN_MTU) {
 935                         mtu = IPV6_MIN_MTU;
 936                         df = 0;
 937                 }
 938
 939                 if (tunnel->parms.iph.daddr)
 940                         skb_dst_update_pmtu(skb, mtu);
 941
 942                 if (skb->len > mtu && !skb_is_gso(skb)) {
 943                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 944                         ip_rt_put(rt);
 945                         goto tx_error;
 946                 }
 947         }
 948
 949         if (tunnel->err_count > 0) {
 950                 if (time_before(jiffies,
 951                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 952                         tunnel->err_count--;
 953                         dst_link_failure(skb);
 954                 } else
 955                         tunnel->err_count = 0;
 956         }
 957
 958         /*
 959          * Okay, now see if we can stuff it in the buffer as-is.
 960          */
 961         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 962
 963         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 964             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 965                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 966                 if (!new_skb) {
 967                         ip_rt_put(rt);
 968                         dev->stats.tx_dropped++;
 969                         kfree_skb(skb);
 970                         return NETDEV_TX_OK;
 971                 }
 972                 if (skb->sk)
 973                         skb_set_owner_w(new_skb, skb->sk);
 974                 dev_kfree_skb(skb);
 975                 skb = new_skb;
 976                 iph6 = ipv6_hdr(skb);
 977         }
 978         ttl = tiph->ttl;
 979         if (ttl == 0)
 980                 ttl = iph6->hop_limit;
 981         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 982
 983         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 984                 ip_rt_put(rt);
 985                 goto tx_error;
 986         }
 987
 988         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 989
 990         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 991                       df, !net_eq(tunnel->net, dev_net(dev)));
 992         return NETDEV_TX_OK;
 993
 994 tx_error_icmp:
 995         dst_link_failure(skb);
 996 tx_error:
 997         kfree_skb(skb);
 998         dev->stats.tx_errors++;
 999         return NETDEV_TX_OK;
1000 }
1001
1002 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1003                                      struct net_device *dev, u8 ipproto)
1004 {
1005         struct ip_tunnel *tunnel = netdev_priv(dev);
1006         const struct iphdr  *tiph = &tunnel->parms.iph;
1007
1008         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1009                 goto tx_error;
1010
1011         skb_set_inner_ipproto(skb, ipproto);
1012
1013         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1014         return NETDEV_TX_OK;
1015 tx_error:
1016         kfree_skb(skb);
1017         dev->stats.tx_errors++;
1018         return NETDEV_TX_OK;
1019 }
1020
1021 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1022                                    struct net_device *dev)
1023 {
1024         switch (skb->protocol) {
1025         case htons(ETH_P_IP):
1026                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1027                 break;
1028         case htons(ETH_P_IPV6):
1029                 ipip6_tunnel_xmit(skb, dev);
1030                 break;
1031 #if IS_ENABLED(CONFIG_MPLS)
1032         case htons(ETH_P_MPLS_UC):
1033                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1034                 break;
1035 #endif
1036         default:
1037                 goto tx_err;
1038         }
1039
1040         return NETDEV_TX_OK;
1041
1042 tx_err:
1043         dev->stats.tx_errors++;
1044         kfree_skb(skb);
1045         return NETDEV_TX_OK;
1046
1047 }
1048
1049 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1050 {
1051         struct net_device *tdev = NULL;
1052         struct ip_tunnel *tunnel;
1053         const struct iphdr *iph;
1054         struct flowi4 fl4;
1055
1056         tunnel = netdev_priv(dev);
1057         iph = &tunnel->parms.iph;
1058
1059         if (iph->daddr) {
1060                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1061                                                           NULL,
1062                                                           iph->daddr, iph->saddr,
1063                                                           0, 0,
1064                                                           IPPROTO_IPV6,
1065                                                           RT_TOS(iph->tos),
1066                                                           tunnel->parms.link);
1067
1068                 if (!IS_ERR(rt)) {
1069                         tdev = rt->dst.dev;
1070                         ip_rt_put(rt);
1071                 }
1072                 dev->flags |= IFF_POINTOPOINT;
1073         }
1074
1075         if (!tdev && tunnel->parms.link)
1076                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1077
1078         if (tdev) {
1079                 int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1080
1081                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1082                 dev->mtu = tdev->mtu - t_hlen;
1083                 if (dev->mtu < IPV6_MIN_MTU)
1084                         dev->mtu = IPV6_MIN_MTU;
1085         }
1086 }
1087
1088 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1089                                 __u32 fwmark)
1090 {
1091         struct net *net = t->net;
1092         struct sit_net *sitn = net_generic(net, sit_net_id);
1093
1094         ipip6_tunnel_unlink(sitn, t);
1095         synchronize_net();
1096         t->parms.iph.saddr = p->iph.saddr;
1097         t->parms.iph.daddr = p->iph.daddr;
1098         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1099         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1100         ipip6_tunnel_link(sitn, t);
1101         t->parms.iph.ttl = p->iph.ttl;
1102         t->parms.iph.tos = p->iph.tos;
1103         t->parms.iph.frag_off = p->iph.frag_off;
1104         if (t->parms.link != p->link || t->fwmark != fwmark) {
1105                 t->parms.link = p->link;
1106                 t->fwmark = fwmark;
1107                 ipip6_tunnel_bind_dev(t->dev);
1108         }
1109         dst_cache_reset(&t->dst_cache);
1110         netdev_state_change(t->dev);
1111 }
1112
1113 #ifdef CONFIG_IPV6_SIT_6RD
1114 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1115                                    struct ip_tunnel_6rd *ip6rd)
1116 {
1117         struct in6_addr prefix;
1118         __be32 relay_prefix;
1119
1120         if (ip6rd->relay_prefixlen > 32 ||
1121             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1122                 return -EINVAL;
1123
1124         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1125         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1126                 return -EINVAL;
1127         if (ip6rd->relay_prefixlen)
1128                 relay_prefix = ip6rd->relay_prefix &
1129                                htonl(0xffffffffUL <<
1130                                      (32 - ip6rd->relay_prefixlen));
1131         else
1132                 relay_prefix = 0;
1133         if (relay_prefix != ip6rd->relay_prefix)
1134                 return -EINVAL;
1135
1136         t->ip6rd.prefix = prefix;
1137         t->ip6rd.relay_prefix = relay_prefix;
1138         t->ip6rd.prefixlen = ip6rd->prefixlen;
1139         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1140         dst_cache_reset(&t->dst_cache);
1141         netdev_state_change(t->dev);
1142         return 0;
1143 }
1144 #endif
1145
1146 static bool ipip6_valid_ip_proto(u8 ipproto)
1147 {
1148         return ipproto == IPPROTO_IPV6 ||
1149                 ipproto == IPPROTO_IPIP ||
1150 #if IS_ENABLED(CONFIG_MPLS)
1151                 ipproto == IPPROTO_MPLS ||
1152 #endif
1153                 ipproto == 0;
1154 }
1155
1156 static int
1157 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1158 {
1159         int err = 0;
1160         struct ip_tunnel_parm p;
1161         struct ip_tunnel_prl prl;
1162         struct ip_tunnel *t = netdev_priv(dev);
1163         struct net *net = t->net;
1164         struct sit_net *sitn = net_generic(net, sit_net_id);
1165 #ifdef CONFIG_IPV6_SIT_6RD
1166         struct ip_tunnel_6rd ip6rd;
1167 #endif
1168
1169         switch (cmd) {
1170         case SIOCGETTUNNEL:
1171 #ifdef CONFIG_IPV6_SIT_6RD
1172         case SIOCGET6RD:
1173 #endif
1174                 if (dev == sitn->fb_tunnel_dev) {
1175                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1176                                 err = -EFAULT;
1177                                 break;
1178                         }
1179                         t = ipip6_tunnel_locate(net, &p, 0);
1180                         if (!t)
1181                                 t = netdev_priv(dev);
1182                 }
1183
1184                 err = -EFAULT;
1185                 if (cmd == SIOCGETTUNNEL) {
1186                         memcpy(&p, &t->parms, sizeof(p));
1187                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1188                                          sizeof(p)))
1189                                 goto done;
1190 #ifdef CONFIG_IPV6_SIT_6RD
1191                 } else {
1192                         ip6rd.prefix = t->ip6rd.prefix;
1193                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1194                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1195                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1196                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1197                                          sizeof(ip6rd)))
1198                                 goto done;
1199 #endif
1200                 }
1201                 err = 0;
1202                 break;
1203
1204         case SIOCADDTUNNEL:
1205         case SIOCCHGTUNNEL:
1206                 err = -EPERM;
1207                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1208                         goto done;
1209
1210                 err = -EFAULT;
1211                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1212                         goto done;
1213
1214                 err = -EINVAL;
1215                 if (!ipip6_valid_ip_proto(p.iph.protocol))
1216                         goto done;
1217                 if (p.iph.version != 4 ||
1218                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1219                         goto done;
1220                 if (p.iph.ttl)
1221                         p.iph.frag_off |= htons(IP_DF);
1222
1223                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1224
1225                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1226                         if (t) {
1227                                 if (t->dev != dev) {
1228                                         err = -EEXIST;
1229                                         break;
1230                                 }
1231                         } else {
1232                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1233                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1234                                         err = -EINVAL;
1235                                         break;
1236                                 }
1237                                 t = netdev_priv(dev);
1238                         }
1239
1240                         ipip6_tunnel_update(t, &p, t->fwmark);
1241                 }
1242
1243                 if (t) {
1244                         err = 0;
1245                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1246                                 err = -EFAULT;
1247                 } else
1248                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1249                 break;
1250
1251         case SIOCDELTUNNEL:
1252                 err = -EPERM;
1253                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1254                         goto done;
1255
1256                 if (dev == sitn->fb_tunnel_dev) {
1257                         err = -EFAULT;
1258                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1259                                 goto done;
1260                         err = -ENOENT;
1261                         t = ipip6_tunnel_locate(net, &p, 0);
1262                         if (!t)
1263                                 goto done;
1264                         err = -EPERM;
1265                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1266                                 goto done;
1267                         dev = t->dev;
1268                 }
1269                 unregister_netdevice(dev);
1270                 err = 0;
1271                 break;
1272
1273         case SIOCGETPRL:
1274                 err = -EINVAL;
1275                 if (dev == sitn->fb_tunnel_dev)
1276                         goto done;
1277                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1278                 break;
1279
1280         case SIOCADDPRL:
1281         case SIOCDELPRL:
1282         case SIOCCHGPRL:
1283                 err = -EPERM;
1284                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1285                         goto done;
1286                 err = -EINVAL;
1287                 if (dev == sitn->fb_tunnel_dev)
1288                         goto done;
1289                 err = -EFAULT;
1290                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1291                         goto done;
1292
1293                 switch (cmd) {
1294                 case SIOCDELPRL:
1295                         err = ipip6_tunnel_del_prl(t, &prl);
1296                         break;
1297                 case SIOCADDPRL:
1298                 case SIOCCHGPRL:
1299                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1300                         break;
1301                 }
1302                 dst_cache_reset(&t->dst_cache);
1303                 netdev_state_change(dev);
1304                 break;
1305
1306 #ifdef CONFIG_IPV6_SIT_6RD
1307         case SIOCADD6RD:
1308         case SIOCCHG6RD:
1309         case SIOCDEL6RD:
1310                 err = -EPERM;
1311                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1312                         goto done;
1313
1314                 err = -EFAULT;
1315                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1316                                    sizeof(ip6rd)))
1317                         goto done;
1318
1319                 if (cmd != SIOCDEL6RD) {
1320                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1321                         if (err < 0)
1322                                 goto done;
1323                 } else
1324                         ipip6_tunnel_clone_6rd(dev, sitn);
1325
1326                 err = 0;
1327                 break;
1328 #endif
1329
1330         default:
1331                 err = -EINVAL;
1332         }
1333
1334 done:
1335         return err;
1336 }
1337
1338 static const struct net_device_ops ipip6_netdev_ops = {
1339         .ndo_init       = ipip6_tunnel_init,
1340         .ndo_uninit     = ipip6_tunnel_uninit,
1341         .ndo_start_xmit = sit_tunnel_xmit,
1342         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1343         .ndo_get_stats64 = ip_tunnel_get_stats64,
1344         .ndo_get_iflink = ip_tunnel_get_iflink,
1345 };
1346
1347 static void ipip6_dev_free(struct net_device *dev)
1348 {
1349         struct ip_tunnel *tunnel = netdev_priv(dev);
1350
1351         dst_cache_destroy(&tunnel->dst_cache);
1352         free_percpu(dev->tstats);
1353 }
1354
1355 #define SIT_FEATURES (NETIF_F_SG           | \
1356                       NETIF_F_FRAGLIST     | \
1357                       NETIF_F_HIGHDMA      | \
1358                       NETIF_F_GSO_SOFTWARE | \
1359                       NETIF_F_HW_CSUM)
1360
1361 static void ipip6_tunnel_setup(struct net_device *dev)
1362 {
1363         struct ip_tunnel *tunnel = netdev_priv(dev);
1364         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1365
1366         dev->netdev_ops         = &ipip6_netdev_ops;
1367         dev->needs_free_netdev  = true;
1368         dev->priv_destructor    = ipip6_dev_free;
1369
1370         dev->type               = ARPHRD_SIT;
1371         dev->hard_header_len    = LL_MAX_HEADER + t_hlen;
1372         dev->mtu                = ETH_DATA_LEN - t_hlen;
1373         dev->min_mtu            = IPV6_MIN_MTU;
1374         dev->max_mtu            = IP6_MAX_MTU - t_hlen;
1375         dev->flags              = IFF_NOARP;
1376         netif_keep_dst(dev);
1377         dev->addr_len           = 4;
1378         dev->features           |= NETIF_F_LLTX;
1379         dev->features           |= SIT_FEATURES;
1380         dev->hw_features        |= SIT_FEATURES;
1381 }
1382
1383 static int ipip6_tunnel_init(struct net_device *dev)
1384 {
1385         struct ip_tunnel *tunnel = netdev_priv(dev);
1386         int err;
1387
1388         tunnel->dev = dev;
1389         tunnel->net = dev_net(dev);
1390         strcpy(tunnel->parms.name, dev->name);
1391
1392         ipip6_tunnel_bind_dev(dev);
1393         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1394         if (!dev->tstats)
1395                 return -ENOMEM;
1396
1397         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1398         if (err) {
1399                 free_percpu(dev->tstats);
1400                 dev->tstats = NULL;
1401                 return err;
1402         }
1403
1404         return 0;
1405 }
1406
1407 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1408 {
1409         struct ip_tunnel *tunnel = netdev_priv(dev);
1410         struct iphdr *iph = &tunnel->parms.iph;
1411         struct net *net = dev_net(dev);
1412         struct sit_net *sitn = net_generic(net, sit_net_id);
1413
1414         iph->version            = 4;
1415         iph->protocol           = IPPROTO_IPV6;
1416         iph->ihl                = 5;
1417         iph->ttl                = 64;
1418
1419         dev_hold(dev);
1420         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1421 }
1422
1423 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1424                           struct netlink_ext_ack *extack)
1425 {
1426         u8 proto;
1427
1428         if (!data || !data[IFLA_IPTUN_PROTO])
1429                 return 0;
1430
1431         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1432         if (!ipip6_valid_ip_proto(proto))
1433                 return -EINVAL;
1434
1435         return 0;
1436 }
1437
1438 static void ipip6_netlink_parms(struct nlattr *data[],
1439                                 struct ip_tunnel_parm *parms,
1440                                 __u32 *fwmark)
1441 {
1442         memset(parms, 0, sizeof(*parms));
1443
1444         parms->iph.version = 4;
1445         parms->iph.protocol = IPPROTO_IPV6;
1446         parms->iph.ihl = 5;
1447         parms->iph.ttl = 64;
1448
1449         if (!data)
1450                 return;
1451
1452         if (data[IFLA_IPTUN_LINK])
1453                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1454
1455         if (data[IFLA_IPTUN_LOCAL])
1456                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1457
1458         if (data[IFLA_IPTUN_REMOTE])
1459                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1460
1461         if (data[IFLA_IPTUN_TTL]) {
1462                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1463                 if (parms->iph.ttl)
1464                         parms->iph.frag_off = htons(IP_DF);
1465         }
1466
1467         if (data[IFLA_IPTUN_TOS])
1468                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1469
1470         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1471                 parms->iph.frag_off = htons(IP_DF);
1472
1473         if (data[IFLA_IPTUN_FLAGS])
1474                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1475
1476         if (data[IFLA_IPTUN_PROTO])
1477                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1478
1479         if (data[IFLA_IPTUN_FWMARK])
1480                 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1481 }
1482
1483 /* This function returns true when ENCAP attributes are present in the nl msg */
1484 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1485                                       struct ip_tunnel_encap *ipencap)
1486 {
1487         bool ret = false;
1488
1489         memset(ipencap, 0, sizeof(*ipencap));
1490
1491         if (!data)
1492                 return ret;
1493
1494         if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1495                 ret = true;
1496                 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1497         }
1498
1499         if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1500                 ret = true;
1501                 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1502         }
1503
1504         if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1505                 ret = true;
1506                 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1507         }
1508
1509         if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1510                 ret = true;
1511                 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1512         }
1513
1514         return ret;
1515 }
1516
1517 #ifdef CONFIG_IPV6_SIT_6RD
1518 /* This function returns true when 6RD attributes are present in the nl msg */
1519 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1520                                     struct ip_tunnel_6rd *ip6rd)
1521 {
1522         bool ret = false;
1523         memset(ip6rd, 0, sizeof(*ip6rd));
1524
1525         if (!data)
1526                 return ret;
1527
1528         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1529                 ret = true;
1530                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1531         }
1532
1533         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1534                 ret = true;
1535                 ip6rd->relay_prefix =
1536                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1537         }
1538
1539         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1540                 ret = true;
1541                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1542         }
1543
1544         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1545                 ret = true;
1546                 ip6rd->relay_prefixlen =
1547                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1548         }
1549
1550         return ret;
1551 }
1552 #endif
1553
1554 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1555                          struct nlattr *tb[], struct nlattr *data[],
1556                          struct netlink_ext_ack *extack)
1557 {
1558         struct net *net = dev_net(dev);
1559         struct ip_tunnel *nt;
1560         struct ip_tunnel_encap ipencap;
1561 #ifdef CONFIG_IPV6_SIT_6RD
1562         struct ip_tunnel_6rd ip6rd;
1563 #endif
1564         int err;
1565
1566         nt = netdev_priv(dev);
1567
1568         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1569                 err = ip_tunnel_encap_setup(nt, &ipencap);
1570                 if (err < 0)
1571                         return err;
1572         }
1573
1574         ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1575
1576         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1577                 return -EEXIST;
1578
1579         err = ipip6_tunnel_create(dev);
1580         if (err < 0)
1581                 return err;
1582
1583         if (tb[IFLA_MTU]) {
1584                 u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1585
1586                 if (mtu >= IPV6_MIN_MTU &&
1587                     mtu <= IP6_MAX_MTU - dev->hard_header_len)
1588                         dev->mtu = mtu;
1589         }
1590
1591 #ifdef CONFIG_IPV6_SIT_6RD
1592         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1593                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1594 #endif
1595
1596         return err;
1597 }
1598
1599 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1600                             struct nlattr *data[],
1601                             struct netlink_ext_ack *extack)
1602 {
1603         struct ip_tunnel *t = netdev_priv(dev);
1604         struct ip_tunnel_parm p;
1605         struct ip_tunnel_encap ipencap;
1606         struct net *net = t->net;
1607         struct sit_net *sitn = net_generic(net, sit_net_id);
1608 #ifdef CONFIG_IPV6_SIT_6RD
1609         struct ip_tunnel_6rd ip6rd;
1610 #endif
1611         __u32 fwmark = t->fwmark;
1612         int err;
1613
1614         if (dev == sitn->fb_tunnel_dev)
1615                 return -EINVAL;
1616
1617         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1618                 err = ip_tunnel_encap_setup(t, &ipencap);
1619                 if (err < 0)
1620                         return err;
1621         }
1622
1623         ipip6_netlink_parms(data, &p, &fwmark);
1624
1625         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1626             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1627                 return -EINVAL;
1628
1629         t = ipip6_tunnel_locate(net, &p, 0);
1630
1631         if (t) {
1632                 if (t->dev != dev)
1633                         return -EEXIST;
1634         } else
1635                 t = netdev_priv(dev);
1636
1637         ipip6_tunnel_update(t, &p, fwmark);
1638
1639 #ifdef CONFIG_IPV6_SIT_6RD
1640         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1641                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1642 #endif
1643
1644         return 0;
1645 }
1646
1647 static size_t ipip6_get_size(const struct net_device *dev)
1648 {
1649         return
1650                 /* IFLA_IPTUN_LINK */
1651                 nla_total_size(4) +
1652                 /* IFLA_IPTUN_LOCAL */
1653                 nla_total_size(4) +
1654                 /* IFLA_IPTUN_REMOTE */
1655                 nla_total_size(4) +
1656                 /* IFLA_IPTUN_TTL */
1657                 nla_total_size(1) +
1658                 /* IFLA_IPTUN_TOS */
1659                 nla_total_size(1) +
1660                 /* IFLA_IPTUN_PMTUDISC */
1661                 nla_total_size(1) +
1662                 /* IFLA_IPTUN_FLAGS */
1663                 nla_total_size(2) +
1664                 /* IFLA_IPTUN_PROTO */
1665                 nla_total_size(1) +
1666 #ifdef CONFIG_IPV6_SIT_6RD
1667                 /* IFLA_IPTUN_6RD_PREFIX */
1668                 nla_total_size(sizeof(struct in6_addr)) +
1669                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1670                 nla_total_size(4) +
1671                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1672                 nla_total_size(2) +
1673                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1674                 nla_total_size(2) +
1675 #endif
1676                 /* IFLA_IPTUN_ENCAP_TYPE */
1677                 nla_total_size(2) +
1678                 /* IFLA_IPTUN_ENCAP_FLAGS */
1679                 nla_total_size(2) +
1680                 /* IFLA_IPTUN_ENCAP_SPORT */
1681                 nla_total_size(2) +
1682                 /* IFLA_IPTUN_ENCAP_DPORT */
1683                 nla_total_size(2) +
1684                 /* IFLA_IPTUN_FWMARK */
1685                 nla_total_size(4) +
1686                 0;
1687 }
1688
1689 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1690 {
1691         struct ip_tunnel *tunnel = netdev_priv(dev);
1692         struct ip_tunnel_parm *parm = &tunnel->parms;
1693
1694         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1695             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1696             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1697             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1698             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1699             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1700                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1701             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1702             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1703             nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1704                 goto nla_put_failure;
1705
1706 #ifdef CONFIG_IPV6_SIT_6RD
1707         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1708                              &tunnel->ip6rd.prefix) ||
1709             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1710                             tunnel->ip6rd.relay_prefix) ||
1711             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1712                         tunnel->ip6rd.prefixlen) ||
1713             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1714                         tunnel->ip6rd.relay_prefixlen))
1715                 goto nla_put_failure;
1716 #endif
1717
1718         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1719                         tunnel->encap.type) ||
1720             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1721                         tunnel->encap.sport) ||
1722             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1723                         tunnel->encap.dport) ||
1724             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1725                         tunnel->encap.flags))
1726                 goto nla_put_failure;
1727
1728         return 0;
1729
1730 nla_put_failure:
1731         return -EMSGSIZE;
1732 }
1733
1734 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1735         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1736         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1737         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1738         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1739         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1740         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1741         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1742         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1743 #ifdef CONFIG_IPV6_SIT_6RD
1744         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1745         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1746         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1747         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1748 #endif
1749         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1750         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1751         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1752         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1753         [IFLA_IPTUN_FWMARK]             = { .type = NLA_U32 },
1754 };
1755
1756 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1757 {
1758         struct net *net = dev_net(dev);
1759         struct sit_net *sitn = net_generic(net, sit_net_id);
1760
1761         if (dev != sitn->fb_tunnel_dev)
1762                 unregister_netdevice_queue(dev, head);
1763 }
1764
1765 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1766         .kind           = "sit",
1767         .maxtype        = IFLA_IPTUN_MAX,
1768         .policy         = ipip6_policy,
1769         .priv_size      = sizeof(struct ip_tunnel),
1770         .setup          = ipip6_tunnel_setup,
1771         .validate       = ipip6_validate,
1772         .newlink        = ipip6_newlink,
1773         .changelink     = ipip6_changelink,
1774         .get_size       = ipip6_get_size,
1775         .fill_info      = ipip6_fill_info,
1776         .dellink        = ipip6_dellink,
1777         .get_link_net   = ip_tunnel_get_link_net,
1778 };
1779
1780 static struct xfrm_tunnel sit_handler __read_mostly = {
1781         .handler        =       ipip6_rcv,
1782         .err_handler    =       ipip6_err,
1783         .priority       =       1,
1784 };
1785
1786 static struct xfrm_tunnel ipip_handler __read_mostly = {
1787         .handler        =       ipip_rcv,
1788         .err_handler    =       ipip6_err,
1789         .priority       =       2,
1790 };
1791
1792 #if IS_ENABLED(CONFIG_MPLS)
1793 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1794         .handler        =       mplsip_rcv,
1795         .err_handler    =       ipip6_err,
1796         .priority       =       2,
1797 };
1798 #endif
1799
1800 static void __net_exit sit_destroy_tunnels(struct net *net,
1801                                            struct list_head *head)
1802 {
1803         struct sit_net *sitn = net_generic(net, sit_net_id);
1804         struct net_device *dev, *aux;
1805         int prio;
1806
1807         for_each_netdev_safe(net, dev, aux)
1808                 if (dev->rtnl_link_ops == &sit_link_ops)
1809                         unregister_netdevice_queue(dev, head);
1810
1811         for (prio = 1; prio < 4; prio++) {
1812                 int h;
1813                 for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1814                         struct ip_tunnel *t;
1815
1816                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1817                         while (t) {
1818                                 /* If dev is in the same netns, it has already
1819                                  * been added to the list by the previous loop.
1820                                  */
1821                                 if (!net_eq(dev_net(t->dev), net))
1822                                         unregister_netdevice_queue(t->dev,
1823                                                                    head);
1824                                 t = rtnl_dereference(t->next);
1825                         }
1826                 }
1827         }
1828 }
1829
1830 static int __net_init sit_init_net(struct net *net)
1831 {
1832         struct sit_net *sitn = net_generic(net, sit_net_id);
1833         struct ip_tunnel *t;
1834         int err;
1835
1836         sitn->tunnels[0] = sitn->tunnels_wc;
1837         sitn->tunnels[1] = sitn->tunnels_l;
1838         sitn->tunnels[2] = sitn->tunnels_r;
1839         sitn->tunnels[3] = sitn->tunnels_r_l;
1840
1841         if (!net_has_fallback_tunnels(net))
1842                 return 0;
1843
1844         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1845                                            NET_NAME_UNKNOWN,
1846                                            ipip6_tunnel_setup);
1847         if (!sitn->fb_tunnel_dev) {
1848                 err = -ENOMEM;
1849                 goto err_alloc_dev;
1850         }
1851         dev_net_set(sitn->fb_tunnel_dev, net);
1852         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1853         /* FB netdevice is special: we have one, and only one per netns.
1854          * Allowing to move it to another netns is clearly unsafe.
1855          */
1856         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1857
1858         err = register_netdev(sitn->fb_tunnel_dev);
1859         if (err)
1860                 goto err_reg_dev;
1861
1862         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1863         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1864
1865         t = netdev_priv(sitn->fb_tunnel_dev);
1866
1867         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1868         return 0;
1869
1870 err_reg_dev:
1871         ipip6_dev_free(sitn->fb_tunnel_dev);
1872 err_alloc_dev:
1873         return err;
1874 }
1875
1876 static void __net_exit sit_exit_batch_net(struct list_head *net_list)
1877 {
1878         LIST_HEAD(list);
1879         struct net *net;
1880
1881         rtnl_lock();
1882         list_for_each_entry(net, net_list, exit_list)
1883                 sit_destroy_tunnels(net, &list);
1884
1885         unregister_netdevice_many(&list);
1886         rtnl_unlock();
1887 }
1888
1889 static struct pernet_operations sit_net_ops = {
1890         .init = sit_init_net,
1891         .exit_batch = sit_exit_batch_net,
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_LICENSE("GPL");
1958 MODULE_ALIAS_RTNL_LINK("sit");
1959 MODULE_ALIAS_NETDEV("sit0");