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             <roque@di.fc.ul.pt>
   8  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   9  *
  10  *      Changes:
  11  * Roger Venning <r.venning@telstra.com>:       6to4 support
  12  * Nate Thompson <nate@thebog.net>:             6to4 support
  13  * Fred Templin <fred.l.templin@boeing.com>:    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
  55 /*
  56    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  57
  58    For comments look at net/ipv4/ip_gre.c --ANK
  59  */
  60
  61 #define IP6_SIT_HASH_SIZE  16
  62 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  63
  64 static bool log_ecn_error = true;
  65 module_param(log_ecn_error, bool, 0644);
  66 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  67
  68 static int ipip6_tunnel_init(struct net_device *dev);
  69 static void ipip6_tunnel_setup(struct net_device *dev);
  70 static void ipip6_dev_free(struct net_device *dev);
  71 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  72                       __be32 *v4dst);
  73 static struct rtnl_link_ops sit_link_ops __read_mostly;
  74
  75 static unsigned int sit_net_id __read_mostly;
  76 struct sit_net {
  77         struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
  78         struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
  79         struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
  80         struct ip_tunnel __rcu *tunnels_wc[1];
  81         struct ip_tunnel __rcu **tunnels[4];
  82
  83         struct net_device *fb_tunnel_dev;
  84 };
  85
  86 static inline struct sit_net *dev_to_sit_net(struct net_device *dev)
  87 {
  88         struct ip_tunnel *t = netdev_priv(dev);
  89
  90         return net_generic(t->net, sit_net_id);
  91 }
  92
  93 /*
  94  * Must be invoked with rcu_read_lock
  95  */
  96 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  97                                              struct net_device *dev,
  98                                              __be32 remote, __be32 local,
  99                                              int sifindex)
 100 {
 101         unsigned int h0 = HASH(remote);
 102         unsigned int h1 = HASH(local);
 103         struct ip_tunnel *t;
 104         struct sit_net *sitn = net_generic(net, sit_net_id);
 105         int ifindex = dev ? dev->ifindex : 0;
 106
 107         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 108                 if (local == t->parms.iph.saddr &&
 109                     remote == t->parms.iph.daddr &&
 110                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 111                      sifindex == t->parms.link) &&
 112                     (t->dev->flags & IFF_UP))
 113                         return t;
 114         }
 115         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 116                 if (remote == t->parms.iph.daddr &&
 117                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 118                      sifindex == t->parms.link) &&
 119                     (t->dev->flags & IFF_UP))
 120                         return t;
 121         }
 122         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 123                 if (local == t->parms.iph.saddr &&
 124                     (!dev || !t->parms.link || ifindex == t->parms.link ||
 125                      sifindex == t->parms.link) &&
 126                     (t->dev->flags & IFF_UP))
 127                         return t;
 128         }
 129         t = rcu_dereference(sitn->tunnels_wc[0]);
 130         if (t && (t->dev->flags & IFF_UP))
 131                 return t;
 132         return NULL;
 133 }
 134
 135 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 136                 struct ip_tunnel_parm *parms)
 137 {
 138         __be32 remote = parms->iph.daddr;
 139         __be32 local = parms->iph.saddr;
 140         unsigned int h = 0;
 141         int prio = 0;
 142
 143         if (remote) {
 144                 prio |= 2;
 145                 h ^= HASH(remote);
 146         }
 147         if (local) {
 148                 prio |= 1;
 149                 h ^= HASH(local);
 150         }
 151         return &sitn->tunnels[prio][h];
 152 }
 153
 154 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 155                 struct ip_tunnel *t)
 156 {
 157         return __ipip6_bucket(sitn, &t->parms);
 158 }
 159
 160 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 161 {
 162         struct ip_tunnel __rcu **tp;
 163         struct ip_tunnel *iter;
 164
 165         for (tp = ipip6_bucket(sitn, t);
 166              (iter = rtnl_dereference(*tp)) != NULL;
 167              tp = &iter->next) {
 168                 if (t == iter) {
 169                         rcu_assign_pointer(*tp, t->next);
 170                         break;
 171                 }
 172         }
 173 }
 174
 175 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 176 {
 177         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 178
 179         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 180         rcu_assign_pointer(*tp, t);
 181 }
 182
 183 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 184 {
 185 #ifdef CONFIG_IPV6_SIT_6RD
 186         struct ip_tunnel *t = netdev_priv(dev);
 187
 188         if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
 189                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 190                 t->ip6rd.relay_prefix = 0;
 191                 t->ip6rd.prefixlen = 16;
 192                 t->ip6rd.relay_prefixlen = 0;
 193         } else {
 194                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 195                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 196         }
 197 #endif
 198 }
 199
 200 static int ipip6_tunnel_create(struct net_device *dev)
 201 {
 202         struct ip_tunnel *t = netdev_priv(dev);
 203         struct net *net = dev_net(dev);
 204         struct sit_net *sitn = net_generic(net, sit_net_id);
 205         int err;
 206
 207         memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 208         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 209
 210         if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 211                 dev->priv_flags |= IFF_ISATAP;
 212
 213         dev->rtnl_link_ops = &sit_link_ops;
 214
 215         err = register_netdevice(dev);
 216         if (err < 0)
 217                 goto out;
 218
 219         ipip6_tunnel_clone_6rd(dev, sitn);
 220
 221         dev_hold(dev);
 222
 223         ipip6_tunnel_link(sitn, t);
 224         return 0;
 225
 226 out:
 227         return err;
 228 }
 229
 230 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 231                 struct ip_tunnel_parm *parms, 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                 strlcpy(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         return nt;
 277
 278 failed_free:
 279         free_netdev(dev);
 280 failed:
 281         return NULL;
 282 }
 283
 284 #define for_each_prl_rcu(start)                 \
 285         for (prl = rcu_dereference(start);      \
 286              prl;                               \
 287              prl = rcu_dereference(prl->next))
 288
 289 static struct ip_tunnel_prl_entry *
 290 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 291 {
 292         struct ip_tunnel_prl_entry *prl;
 293
 294         for_each_prl_rcu(t->prl)
 295                 if (prl->addr == addr)
 296                         break;
 297         return prl;
 298
 299 }
 300
 301 static int ipip6_tunnel_get_prl(struct net_device *dev, struct ifreq *ifr)
 302 {
 303         struct ip_tunnel_prl __user *a = ifr->ifr_ifru.ifru_data;
 304         struct ip_tunnel *t = netdev_priv(dev);
 305         struct ip_tunnel_prl kprl, *kp;
 306         struct ip_tunnel_prl_entry *prl;
 307         unsigned int cmax, c = 0, ca, len;
 308         int ret = 0;
 309
 310         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
 311                 return -EINVAL;
 312
 313         if (copy_from_user(&kprl, a, sizeof(kprl)))
 314                 return -EFAULT;
 315         cmax = kprl.datalen / sizeof(kprl);
 316         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 317                 cmax = 1;
 318
 319         /* For simple GET or for root users,
 320          * we try harder to allocate.
 321          */
 322         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 323                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL | __GFP_NOWARN) :
 324                 NULL;
 325
 326         rcu_read_lock();
 327
 328         ca = t->prl_count < cmax ? 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);
 337                 if (!kp) {
 338                         ret = -ENOMEM;
 339                         goto out;
 340                 }
 341         }
 342
 343         c = 0;
 344         for_each_prl_rcu(t->prl) {
 345                 if (c >= cmax)
 346                         break;
 347                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 348                         continue;
 349                 kp[c].addr = prl->addr;
 350                 kp[c].flags = prl->flags;
 351                 c++;
 352                 if (kprl.addr != htonl(INADDR_ANY))
 353                         break;
 354         }
 355 out:
 356         rcu_read_unlock();
 357
 358         len = sizeof(*kp) * c;
 359         ret = 0;
 360         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 361                 ret = -EFAULT;
 362
 363         kfree(kp);
 364
 365         return ret;
 366 }
 367
 368 static int
 369 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 370 {
 371         struct ip_tunnel_prl_entry *p;
 372         int err = 0;
 373
 374         if (a->addr == htonl(INADDR_ANY))
 375                 return -EINVAL;
 376
 377         ASSERT_RTNL();
 378
 379         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 380                 if (p->addr == a->addr) {
 381                         if (chg) {
 382                                 p->flags = a->flags;
 383                                 goto out;
 384                         }
 385                         err = -EEXIST;
 386                         goto out;
 387                 }
 388         }
 389
 390         if (chg) {
 391                 err = -ENXIO;
 392                 goto out;
 393         }
 394
 395         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 396         if (!p) {
 397                 err = -ENOBUFS;
 398                 goto out;
 399         }
 400
 401         p->next = t->prl;
 402         p->addr = a->addr;
 403         p->flags = a->flags;
 404         t->prl_count++;
 405         rcu_assign_pointer(t->prl, p);
 406 out:
 407         return err;
 408 }
 409
 410 static void prl_list_destroy_rcu(struct rcu_head *head)
 411 {
 412         struct ip_tunnel_prl_entry *p, *n;
 413
 414         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 415         do {
 416                 n = rcu_dereference_protected(p->next, 1);
 417                 kfree(p);
 418                 p = n;
 419         } while (p);
 420 }
 421
 422 static int
 423 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 424 {
 425         struct ip_tunnel_prl_entry *x;
 426         struct ip_tunnel_prl_entry __rcu **p;
 427         int err = 0;
 428
 429         ASSERT_RTNL();
 430
 431         if (a && a->addr != htonl(INADDR_ANY)) {
 432                 for (p = &t->prl;
 433                      (x = rtnl_dereference(*p)) != NULL;
 434                      p = &x->next) {
 435                         if (x->addr == a->addr) {
 436                                 *p = x->next;
 437                                 kfree_rcu(x, rcu_head);
 438                                 t->prl_count--;
 439                                 goto out;
 440                         }
 441                 }
 442                 err = -ENXIO;
 443         } else {
 444                 x = rtnl_dereference(t->prl);
 445                 if (x) {
 446                         t->prl_count = 0;
 447                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 448                         t->prl = NULL;
 449                 }
 450         }
 451 out:
 452         return err;
 453 }
 454
 455 static int ipip6_tunnel_prl_ctl(struct net_device *dev, struct ifreq *ifr,
 456                 int cmd)
 457 {
 458         struct ip_tunnel *t = netdev_priv(dev);
 459         struct ip_tunnel_prl prl;
 460         int err;
 461
 462         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
 463                 return -EPERM;
 464         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
 465                 return -EINVAL;
 466
 467         if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
 468                 return -EFAULT;
 469
 470         switch (cmd) {
 471         case SIOCDELPRL:
 472                 err = ipip6_tunnel_del_prl(t, &prl);
 473                 break;
 474         case SIOCADDPRL:
 475         case SIOCCHGPRL:
 476                 err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 477                 break;
 478         }
 479         dst_cache_reset(&t->dst_cache);
 480         netdev_state_change(dev);
 481         return err;
 482 }
 483
 484 static int
 485 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 486 {
 487         struct ip_tunnel_prl_entry *p;
 488         int ok = 1;
 489
 490         rcu_read_lock();
 491         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 492         if (p) {
 493                 if (p->flags & PRL_DEFAULT)
 494                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 495                 else
 496                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 497         } else {
 498                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 499
 500                 if (ipv6_addr_is_isatap(addr6) &&
 501                     (addr6->s6_addr32[3] == iph->saddr) &&
 502                     ipv6_chk_prefix(addr6, t->dev))
 503                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 504                 else
 505                         ok = 0;
 506         }
 507         rcu_read_unlock();
 508         return ok;
 509 }
 510
 511 static void ipip6_tunnel_uninit(struct net_device *dev)
 512 {
 513         struct ip_tunnel *tunnel = netdev_priv(dev);
 514         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 515
 516         if (dev == sitn->fb_tunnel_dev) {
 517                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 518         } else {
 519                 ipip6_tunnel_unlink(sitn, tunnel);
 520                 ipip6_tunnel_del_prl(tunnel, NULL);
 521         }
 522         dst_cache_reset(&tunnel->dst_cache);
 523         dev_put(dev);
 524 }
 525
 526 static int ipip6_err(struct sk_buff *skb, u32 info)
 527 {
 528         const struct iphdr *iph = (const struct iphdr *)skb->data;
 529         const int type = icmp_hdr(skb)->type;
 530         const int code = icmp_hdr(skb)->code;
 531         unsigned int data_len = 0;
 532         struct ip_tunnel *t;
 533         int sifindex;
 534         int err;
 535
 536         switch (type) {
 537         default:
 538         case ICMP_PARAMETERPROB:
 539                 return 0;
 540
 541         case ICMP_DEST_UNREACH:
 542                 switch (code) {
 543                 case ICMP_SR_FAILED:
 544                         /* Impossible event. */
 545                         return 0;
 546                 default:
 547                         /* All others are translated to HOST_UNREACH.
 548                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 549                            I believe they are just ether pollution. --ANK
 550                          */
 551                         break;
 552                 }
 553                 break;
 554         case ICMP_TIME_EXCEEDED:
 555                 if (code != ICMP_EXC_TTL)
 556                         return 0;
 557                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 558                 break;
 559         case ICMP_REDIRECT:
 560                 break;
 561         }
 562
 563         err = -ENOENT;
 564
 565         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 566         t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 567                                 iph->daddr, iph->saddr, sifindex);
 568         if (!t)
 569                 goto out;
 570
 571         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 572                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 573                                  t->parms.link, iph->protocol);
 574                 err = 0;
 575                 goto out;
 576         }
 577         if (type == ICMP_REDIRECT) {
 578                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
 579                               iph->protocol);
 580                 err = 0;
 581                 goto out;
 582         }
 583
 584         err = 0;
 585         if (__in6_dev_get(skb->dev) &&
 586             !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
 587                 goto out;
 588
 589         if (t->parms.iph.daddr == 0)
 590                 goto out;
 591
 592         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 593                 goto out;
 594
 595         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 596                 t->err_count++;
 597         else
 598                 t->err_count = 1;
 599         t->err_time = jiffies;
 600 out:
 601         return err;
 602 }
 603
 604 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 605                                   const struct in6_addr *v6addr)
 606 {
 607         __be32 v4embed = 0;
 608         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 609                 return true;
 610         return false;
 611 }
 612
 613 /* Checks if an address matches an address on the tunnel interface.
 614  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 615  * Long story:
 616  * This function is called after we considered the packet as spoofed
 617  * in is_spoofed_6rd.
 618  * We may have a router that is doing NAT for proto 41 packets
 619  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 620  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 621  * function will return true, dropping the packet.
 622  * But, we can still check if is spoofed against the IP
 623  * addresses associated with the interface.
 624  */
 625 static bool only_dnatted(const struct ip_tunnel *tunnel,
 626         const struct in6_addr *v6dst)
 627 {
 628         int prefix_len;
 629
 630 #ifdef CONFIG_IPV6_SIT_6RD
 631         prefix_len = tunnel->ip6rd.prefixlen + 32
 632                 - tunnel->ip6rd.relay_prefixlen;
 633 #else
 634         prefix_len = 48;
 635 #endif
 636         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 637 }
 638
 639 /* Returns true if a packet is spoofed */
 640 static bool packet_is_spoofed(struct sk_buff *skb,
 641                               const struct iphdr *iph,
 642                               struct ip_tunnel *tunnel)
 643 {
 644         const struct ipv6hdr *ipv6h;
 645
 646         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 647                 if (!isatap_chksrc(skb, iph, tunnel))
 648                         return true;
 649
 650                 return false;
 651         }
 652
 653         if (tunnel->dev->flags & IFF_POINTOPOINT)
 654                 return false;
 655
 656         ipv6h = ipv6_hdr(skb);
 657
 658         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 659                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 660                                      &iph->saddr, &ipv6h->saddr,
 661                                      &iph->daddr, &ipv6h->daddr);
 662                 return true;
 663         }
 664
 665         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 666                 return false;
 667
 668         if (only_dnatted(tunnel, &ipv6h->daddr))
 669                 return false;
 670
 671         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 672                              &iph->saddr, &ipv6h->saddr,
 673                              &iph->daddr, &ipv6h->daddr);
 674         return true;
 675 }
 676
 677 static int ipip6_rcv(struct sk_buff *skb)
 678 {
 679         const struct iphdr *iph = ip_hdr(skb);
 680         struct ip_tunnel *tunnel;
 681         int sifindex;
 682         int err;
 683
 684         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 685         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 686                                      iph->saddr, iph->daddr, sifindex);
 687         if (tunnel) {
 688                 struct pcpu_sw_netstats *tstats;
 689
 690                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 691                     tunnel->parms.iph.protocol != 0)
 692                         goto out;
 693
 694                 skb->mac_header = skb->network_header;
 695                 skb_reset_network_header(skb);
 696                 IPCB(skb)->flags = 0;
 697                 skb->dev = tunnel->dev;
 698
 699                 if (packet_is_spoofed(skb, iph, tunnel)) {
 700                         tunnel->dev->stats.rx_errors++;
 701                         goto out;
 702                 }
 703
 704                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 705                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
 706                         goto out;
 707
 708                 /* skb can be uncloned in iptunnel_pull_header, so
 709                  * old iph is no longer valid
 710                  */
 711                 iph = (const struct iphdr *)skb_mac_header(skb);
 712                 err = IP_ECN_decapsulate(iph, skb);
 713                 if (unlikely(err)) {
 714                         if (log_ecn_error)
 715                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 716                                                      &iph->saddr, iph->tos);
 717                         if (err > 1) {
 718                                 ++tunnel->dev->stats.rx_frame_errors;
 719                                 ++tunnel->dev->stats.rx_errors;
 720                                 goto out;
 721                         }
 722                 }
 723
 724                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 725                 u64_stats_update_begin(&tstats->syncp);
 726                 tstats->rx_packets++;
 727                 tstats->rx_bytes += skb->len;
 728                 u64_stats_update_end(&tstats->syncp);
 729
 730                 netif_rx(skb);
 731
 732                 return 0;
 733         }
 734
 735         /* no tunnel matched,  let upstream know, ipsec may handle it */
 736         return 1;
 737 out:
 738         kfree_skb(skb);
 739         return 0;
 740 }
 741
 742 static const struct tnl_ptk_info ipip_tpi = {
 743         /* no tunnel info required for ipip. */
 744         .proto = htons(ETH_P_IP),
 745 };
 746
 747 #if IS_ENABLED(CONFIG_MPLS)
 748 static const struct tnl_ptk_info mplsip_tpi = {
 749         /* no tunnel info required for mplsip. */
 750         .proto = htons(ETH_P_MPLS_UC),
 751 };
 752 #endif
 753
 754 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
 755 {
 756         const struct iphdr *iph;
 757         struct ip_tunnel *tunnel;
 758         int sifindex;
 759
 760         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
 761
 762         iph = ip_hdr(skb);
 763         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 764                                      iph->saddr, iph->daddr, sifindex);
 765         if (tunnel) {
 766                 const struct tnl_ptk_info *tpi;
 767
 768                 if (tunnel->parms.iph.protocol != ipproto &&
 769                     tunnel->parms.iph.protocol != 0)
 770                         goto drop;
 771
 772                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 773                         goto drop;
 774 #if IS_ENABLED(CONFIG_MPLS)
 775                 if (ipproto == IPPROTO_MPLS)
 776                         tpi = &mplsip_tpi;
 777                 else
 778 #endif
 779                         tpi = &ipip_tpi;
 780                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
 781                         goto drop;
 782                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
 783         }
 784
 785         return 1;
 786
 787 drop:
 788         kfree_skb(skb);
 789         return 0;
 790 }
 791
 792 static int ipip_rcv(struct sk_buff *skb)
 793 {
 794         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
 795 }
 796
 797 #if IS_ENABLED(CONFIG_MPLS)
 798 static int mplsip_rcv(struct sk_buff *skb)
 799 {
 800         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
 801 }
 802 #endif
 803
 804 /*
 805  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 806  * stores the embedded IPv4 address in v4dst and returns true.
 807  */
 808 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 809                       __be32 *v4dst)
 810 {
 811 #ifdef CONFIG_IPV6_SIT_6RD
 812         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 813                               tunnel->ip6rd.prefixlen)) {
 814                 unsigned int pbw0, pbi0;
 815                 int pbi1;
 816                 u32 d;
 817
 818                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 819                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 820
 821                 d = tunnel->ip6rd.relay_prefixlen < 32 ?
 822                         (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 823                     tunnel->ip6rd.relay_prefixlen : 0;
 824
 825                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 826                 if (pbi1 > 0)
 827                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 828                              (32 - pbi1);
 829
 830                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 831                 return true;
 832         }
 833 #else
 834         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 835                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 836                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 837                 return true;
 838         }
 839 #endif
 840         return false;
 841 }
 842
 843 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 844                              const struct in6_addr *v6dst)
 845 {
 846         __be32 dst = 0;
 847         check_6rd(tunnel, v6dst, &dst);
 848         return dst;
 849 }
 850
 851 /*
 852  *      This function assumes it is being called from dev_queue_xmit()
 853  *      and that skb is filled properly by that function.
 854  */
 855
 856 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 857                                      struct net_device *dev)
 858 {
 859         struct ip_tunnel *tunnel = netdev_priv(dev);
 860         const struct iphdr  *tiph = &tunnel->parms.iph;
 861         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 862         u8     tos = tunnel->parms.iph.tos;
 863         __be16 df = tiph->frag_off;
 864         struct rtable *rt;              /* Route to the other host */
 865         struct net_device *tdev;        /* Device to other host */
 866         unsigned int max_headroom;      /* The extra header space needed */
 867         __be32 dst = tiph->daddr;
 868         struct flowi4 fl4;
 869         int    mtu;
 870         const struct in6_addr *addr6;
 871         int addr_type;
 872         u8 ttl;
 873         u8 protocol = IPPROTO_IPV6;
 874         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 875
 876         if (tos == 1)
 877                 tos = ipv6_get_dsfield(iph6);
 878
 879         /* ISATAP (RFC4214) - must come before 6to4 */
 880         if (dev->priv_flags & IFF_ISATAP) {
 881                 struct neighbour *neigh = NULL;
 882                 bool do_tx_error = false;
 883
 884                 if (skb_dst(skb))
 885                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 886
 887                 if (!neigh) {
 888                         net_dbg_ratelimited("nexthop == NULL\n");
 889                         goto tx_error;
 890                 }
 891
 892                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 893                 addr_type = ipv6_addr_type(addr6);
 894
 895                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 896                      ipv6_addr_is_isatap(addr6))
 897                         dst = addr6->s6_addr32[3];
 898                 else
 899                         do_tx_error = true;
 900
 901                 neigh_release(neigh);
 902                 if (do_tx_error)
 903                         goto tx_error;
 904         }
 905
 906         if (!dst)
 907                 dst = try_6rd(tunnel, &iph6->daddr);
 908
 909         if (!dst) {
 910                 struct neighbour *neigh = NULL;
 911                 bool do_tx_error = false;
 912
 913                 if (skb_dst(skb))
 914                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 915
 916                 if (!neigh) {
 917                         net_dbg_ratelimited("nexthop == NULL\n");
 918                         goto tx_error;
 919                 }
 920
 921                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 922                 addr_type = ipv6_addr_type(addr6);
 923
 924                 if (addr_type == IPV6_ADDR_ANY) {
 925                         addr6 = &ipv6_hdr(skb)->daddr;
 926                         addr_type = ipv6_addr_type(addr6);
 927                 }
 928
 929                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 930                         dst = addr6->s6_addr32[3];
 931                 else
 932                         do_tx_error = true;
 933
 934                 neigh_release(neigh);
 935                 if (do_tx_error)
 936                         goto tx_error;
 937         }
 938
 939         flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
 940                            RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
 941                            0, dst, tiph->saddr, 0, 0,
 942                            sock_net_uid(tunnel->net, NULL));
 943
 944         rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
 945         if (!rt) {
 946                 rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
 947                 if (IS_ERR(rt)) {
 948                         dev->stats.tx_carrier_errors++;
 949                         goto tx_error_icmp;
 950                 }
 951                 dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
 952         }
 953
 954         if (rt->rt_type != RTN_UNICAST) {
 955                 ip_rt_put(rt);
 956                 dev->stats.tx_carrier_errors++;
 957                 goto tx_error_icmp;
 958         }
 959         tdev = rt->dst.dev;
 960
 961         if (tdev == dev) {
 962                 ip_rt_put(rt);
 963                 dev->stats.collisions++;
 964                 goto tx_error;
 965         }
 966
 967         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
 968                 ip_rt_put(rt);
 969                 goto tx_error;
 970         }
 971
 972         if (df) {
 973                 mtu = dst_mtu(&rt->dst) - t_hlen;
 974
 975                 if (mtu < 68) {
 976                         dev->stats.collisions++;
 977                         ip_rt_put(rt);
 978                         goto tx_error;
 979                 }
 980
 981                 if (mtu < IPV6_MIN_MTU) {
 982                         mtu = IPV6_MIN_MTU;
 983                         df = 0;
 984                 }
 985
 986                 if (tunnel->parms.iph.daddr)
 987                         skb_dst_update_pmtu_no_confirm(skb, mtu);
 988
 989                 if (skb->len > mtu && !skb_is_gso(skb)) {
 990                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 991                         ip_rt_put(rt);
 992                         goto tx_error;
 993                 }
 994         }
 995
 996         if (tunnel->err_count > 0) {
 997                 if (time_before(jiffies,
 998                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 999                         tunnel->err_count--;
1000                         dst_link_failure(skb);
1001                 } else
1002                         tunnel->err_count = 0;
1003         }
1004
1005         /*
1006          * Okay, now see if we can stuff it in the buffer as-is.
1007          */
1008         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
1009
1010         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1011             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1012                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
1013                 if (!new_skb) {
1014                         ip_rt_put(rt);
1015                         dev->stats.tx_dropped++;
1016                         kfree_skb(skb);
1017                         return NETDEV_TX_OK;
1018                 }
1019                 if (skb->sk)
1020                         skb_set_owner_w(new_skb, skb->sk);
1021                 dev_kfree_skb(skb);
1022                 skb = new_skb;
1023                 iph6 = ipv6_hdr(skb);
1024         }
1025         ttl = tiph->ttl;
1026         if (ttl == 0)
1027                 ttl = iph6->hop_limit;
1028         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
1029
1030         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
1031                 ip_rt_put(rt);
1032                 goto tx_error;
1033         }
1034
1035         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
1036
1037         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
1038                       df, !net_eq(tunnel->net, dev_net(dev)));
1039         return NETDEV_TX_OK;
1040
1041 tx_error_icmp:
1042         dst_link_failure(skb);
1043 tx_error:
1044         kfree_skb(skb);
1045         dev->stats.tx_errors++;
1046         return NETDEV_TX_OK;
1047 }
1048
1049 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1050                                      struct net_device *dev, u8 ipproto)
1051 {
1052         struct ip_tunnel *tunnel = netdev_priv(dev);
1053         const struct iphdr  *tiph = &tunnel->parms.iph;
1054
1055         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1056                 goto tx_error;
1057
1058         skb_set_inner_ipproto(skb, ipproto);
1059
1060         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1061         return NETDEV_TX_OK;
1062 tx_error:
1063         kfree_skb(skb);
1064         dev->stats.tx_errors++;
1065         return NETDEV_TX_OK;
1066 }
1067
1068 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1069                                    struct net_device *dev)
1070 {
1071         if (!pskb_inet_may_pull(skb))
1072                 goto tx_err;
1073
1074         switch (skb->protocol) {
1075         case htons(ETH_P_IP):
1076                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1077                 break;
1078         case htons(ETH_P_IPV6):
1079                 ipip6_tunnel_xmit(skb, dev);
1080                 break;
1081 #if IS_ENABLED(CONFIG_MPLS)
1082         case htons(ETH_P_MPLS_UC):
1083                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1084                 break;
1085 #endif
1086         default:
1087                 goto tx_err;
1088         }
1089
1090         return NETDEV_TX_OK;
1091
1092 tx_err:
1093         dev->stats.tx_errors++;
1094         kfree_skb(skb);
1095         return NETDEV_TX_OK;
1096
1097 }
1098
1099 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1100 {
1101         struct net_device *tdev = NULL;
1102         struct ip_tunnel *tunnel;
1103         const struct iphdr *iph;
1104         struct flowi4 fl4;
1105
1106         tunnel = netdev_priv(dev);
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                                                           RT_TOS(iph->tos),
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 t_hlen = tunnel->hlen + sizeof(struct iphdr);
1130
1131                 dev->mtu = tdev->mtu - t_hlen;
1132                 if (dev->mtu < IPV6_MIN_MTU)
1133                         dev->mtu = IPV6_MIN_MTU;
1134         }
1135 }
1136
1137 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p,
1138                                 __u32 fwmark)
1139 {
1140         struct net *net = t->net;
1141         struct sit_net *sitn = net_generic(net, sit_net_id);
1142
1143         ipip6_tunnel_unlink(sitn, t);
1144         synchronize_net();
1145         t->parms.iph.saddr = p->iph.saddr;
1146         t->parms.iph.daddr = p->iph.daddr;
1147         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1148         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1149         ipip6_tunnel_link(sitn, t);
1150         t->parms.iph.ttl = p->iph.ttl;
1151         t->parms.iph.tos = p->iph.tos;
1152         t->parms.iph.frag_off = p->iph.frag_off;
1153         if (t->parms.link != p->link || t->fwmark != fwmark) {
1154                 t->parms.link = p->link;
1155                 t->fwmark = fwmark;
1156                 ipip6_tunnel_bind_dev(t->dev);
1157         }
1158         dst_cache_reset(&t->dst_cache);
1159         netdev_state_change(t->dev);
1160 }
1161
1162 #ifdef CONFIG_IPV6_SIT_6RD
1163 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1164                                    struct ip_tunnel_6rd *ip6rd)
1165 {
1166         struct in6_addr prefix;
1167         __be32 relay_prefix;
1168
1169         if (ip6rd->relay_prefixlen > 32 ||
1170             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1171                 return -EINVAL;
1172
1173         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1174         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1175                 return -EINVAL;
1176         if (ip6rd->relay_prefixlen)
1177                 relay_prefix = ip6rd->relay_prefix &
1178                                htonl(0xffffffffUL <<
1179                                      (32 - ip6rd->relay_prefixlen));
1180         else
1181                 relay_prefix = 0;
1182         if (relay_prefix != ip6rd->relay_prefix)
1183                 return -EINVAL;
1184
1185         t->ip6rd.prefix = prefix;
1186         t->ip6rd.relay_prefix = relay_prefix;
1187         t->ip6rd.prefixlen = ip6rd->prefixlen;
1188         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1189         dst_cache_reset(&t->dst_cache);
1190         netdev_state_change(t->dev);
1191         return 0;
1192 }
1193
1194 static int
1195 ipip6_tunnel_get6rd(struct net_device *dev, struct ifreq *ifr)
1196 {
1197         struct ip_tunnel *t = netdev_priv(dev);
1198         struct ip_tunnel_6rd ip6rd;
1199         struct ip_tunnel_parm p;
1200
1201         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1202                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1203                         return -EFAULT;
1204                 t = ipip6_tunnel_locate(t->net, &p, 0);
1205         }
1206         if (!t)
1207                 t = netdev_priv(dev);
1208
1209         ip6rd.prefix = t->ip6rd.prefix;
1210         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1211         ip6rd.prefixlen = t->ip6rd.prefixlen;
1212         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1213         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd, sizeof(ip6rd)))
1214                 return -EFAULT;
1215         return 0;
1216 }
1217
1218 static int
1219 ipip6_tunnel_6rdctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1220 {
1221         struct ip_tunnel *t = netdev_priv(dev);
1222         struct ip_tunnel_6rd ip6rd;
1223         int err;
1224
1225         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1226                 return -EPERM;
1227         if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data, sizeof(ip6rd)))
1228                 return -EFAULT;
1229
1230         if (cmd != SIOCDEL6RD) {
1231                 err = ipip6_tunnel_update_6rd(t, &ip6rd);
1232                 if (err < 0)
1233                         return err;
1234         } else
1235                 ipip6_tunnel_clone_6rd(dev, dev_to_sit_net(dev));
1236         return 0;
1237 }
1238
1239 #endif /* CONFIG_IPV6_SIT_6RD */
1240
1241 static bool ipip6_valid_ip_proto(u8 ipproto)
1242 {
1243         return ipproto == IPPROTO_IPV6 ||
1244                 ipproto == IPPROTO_IPIP ||
1245 #if IS_ENABLED(CONFIG_MPLS)
1246                 ipproto == IPPROTO_MPLS ||
1247 #endif
1248                 ipproto == 0;
1249 }
1250
1251 static int
1252 __ipip6_tunnel_ioctl_validate(struct net *net, struct ip_tunnel_parm *p)
1253 {
1254         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1255                 return -EPERM;
1256
1257         if (!ipip6_valid_ip_proto(p->iph.protocol))
1258                 return -EINVAL;
1259         if (p->iph.version != 4 ||
1260             p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
1261                 return -EINVAL;
1262
1263         if (p->iph.ttl)
1264                 p->iph.frag_off |= htons(IP_DF);
1265         return 0;
1266 }
1267
1268 static int
1269 ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm *p)
1270 {
1271         struct ip_tunnel *t = netdev_priv(dev);
1272
1273         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
1274                 t = ipip6_tunnel_locate(t->net, p, 0);
1275         if (!t)
1276                 t = netdev_priv(dev);
1277         memcpy(p, &t->parms, sizeof(*p));
1278         return 0;
1279 }
1280
1281 static int
1282 ipip6_tunnel_add(struct net_device *dev, struct ip_tunnel_parm *p)
1283 {
1284         struct ip_tunnel *t = netdev_priv(dev);
1285         int err;
1286
1287         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1288         if (err)
1289                 return err;
1290
1291         t = ipip6_tunnel_locate(t->net, p, 1);
1292         if (!t)
1293                 return -ENOBUFS;
1294         return 0;
1295 }
1296
1297 static int
1298 ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm *p)
1299 {
1300         struct ip_tunnel *t = netdev_priv(dev);
1301         int err;
1302
1303         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1304         if (err)
1305                 return err;
1306
1307         t = ipip6_tunnel_locate(t->net, p, 0);
1308         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1309                 if (!t)
1310                         return -ENOENT;
1311         } else {
1312                 if (t) {
1313                         if (t->dev != dev)
1314                                 return -EEXIST;
1315                 } else {
1316                         if (((dev->flags & IFF_POINTOPOINT) && !p->iph.daddr) ||
1317                             (!(dev->flags & IFF_POINTOPOINT) && p->iph.daddr))
1318                                 return -EINVAL;
1319                         t = netdev_priv(dev);
1320                 }
1321
1322                 ipip6_tunnel_update(t, p, t->fwmark);
1323         }
1324
1325         return 0;
1326 }
1327
1328 static int
1329 ipip6_tunnel_del(struct net_device *dev, struct ip_tunnel_parm *p)
1330 {
1331         struct ip_tunnel *t = netdev_priv(dev);
1332
1333         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1334                 return -EPERM;
1335
1336         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1337                 t = ipip6_tunnel_locate(t->net, p, 0);
1338                 if (!t)
1339                         return -ENOENT;
1340                 if (t == netdev_priv(dev_to_sit_net(dev)->fb_tunnel_dev))
1341                         return -EPERM;
1342                 dev = t->dev;
1343         }
1344         unregister_netdevice(dev);
1345         return 0;
1346 }
1347
1348 static int
1349 ipip6_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
1350 {
1351         switch (cmd) {
1352         case SIOCGETTUNNEL:
1353                 return ipip6_tunnel_get(dev, p);
1354         case SIOCADDTUNNEL:
1355                 return ipip6_tunnel_add(dev, p);
1356         case SIOCCHGTUNNEL:
1357                 return ipip6_tunnel_change(dev, p);
1358         case SIOCDELTUNNEL:
1359                 return ipip6_tunnel_del(dev, p);
1360         default:
1361                 return -EINVAL;
1362         }
1363 }
1364
1365 static int
1366 ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1367 {
1368         switch (cmd) {
1369         case SIOCGETTUNNEL:
1370         case SIOCADDTUNNEL:
1371         case SIOCCHGTUNNEL:
1372         case SIOCDELTUNNEL:
1373                 return ip_tunnel_ioctl(dev, ifr, cmd);
1374         case SIOCGETPRL:
1375                 return ipip6_tunnel_get_prl(dev, ifr);
1376         case SIOCADDPRL:
1377         case SIOCDELPRL:
1378         case SIOCCHGPRL:
1379                 return ipip6_tunnel_prl_ctl(dev, ifr, cmd);
1380 #ifdef CONFIG_IPV6_SIT_6RD
1381         case SIOCGET6RD:
1382                 return ipip6_tunnel_get6rd(dev, ifr);
1383         case SIOCADD6RD:
1384         case SIOCCHG6RD:
1385         case SIOCDEL6RD:
1386                 return ipip6_tunnel_6rdctl(dev, ifr, cmd);
1387 #endif
1388         default:
1389                 return -EINVAL;
1390         }
1391 }
1392
1393 static const struct net_device_ops ipip6_netdev_ops = {
1394         .ndo_init       = ipip6_tunnel_init,
1395         .ndo_uninit     = ipip6_tunnel_uninit,
1396         .ndo_start_xmit = sit_tunnel_xmit,
1397         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1398         .ndo_get_stats64 = dev_get_tstats64,
1399         .ndo_get_iflink = ip_tunnel_get_iflink,
1400         .ndo_tunnel_ctl = ipip6_tunnel_ctl,
1401 };
1402
1403 static void ipip6_dev_free(struct net_device *dev)
1404 {
1405         struct ip_tunnel *tunnel = netdev_priv(dev);
1406
1407         dst_cache_destroy(&tunnel->dst_cache);
1408         free_percpu(dev->tstats);
1409 }
1410
1411 #define SIT_FEATURES (NETIF_F_SG           | \
1412                       NETIF_F_FRAGLIST     | \
1413                       NETIF_F_HIGHDMA      | \
1414                       NETIF_F_GSO_SOFTWARE | \
1415                       NETIF_F_HW_CSUM)
1416
1417 static void ipip6_tunnel_setup(struct net_device *dev)
1418 {
1419         struct ip_tunnel *tunnel = netdev_priv(dev);
1420         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1421
1422         dev->netdev_ops         = &ipip6_netdev_ops;
1423         dev->header_ops         = &ip_tunnel_header_ops;
1424         dev->needs_free_netdev  = true;
1425         dev->priv_destructor    = ipip6_dev_free;
1426
1427         dev->type               = ARPHRD_SIT;
1428         dev->mtu                = ETH_DATA_LEN - t_hlen;
1429         dev->min_mtu            = IPV6_MIN_MTU;
1430         dev->max_mtu            = IP6_MAX_MTU - t_hlen;
1431         dev->flags              = IFF_NOARP;
1432         netif_keep_dst(dev);
1433         dev->addr_len           = 4;
1434         dev->features           |= NETIF_F_LLTX;
1435         dev->features           |= SIT_FEATURES;
1436         dev->hw_features        |= SIT_FEATURES;
1437 }
1438
1439 static int ipip6_tunnel_init(struct net_device *dev)
1440 {
1441         struct ip_tunnel *tunnel = netdev_priv(dev);
1442         int err;
1443
1444         tunnel->dev = dev;
1445         tunnel->net = dev_net(dev);
1446         strcpy(tunnel->parms.name, dev->name);
1447
1448         ipip6_tunnel_bind_dev(dev);
1449         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1450         if (!dev->tstats)
1451                 return -ENOMEM;
1452
1453         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1454         if (err) {
1455                 free_percpu(dev->tstats);
1456                 dev->tstats = NULL;
1457                 return err;
1458         }
1459
1460         return 0;
1461 }
1462
1463 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1464 {
1465         struct ip_tunnel *tunnel = netdev_priv(dev);
1466         struct iphdr *iph = &tunnel->parms.iph;
1467         struct net *net = dev_net(dev);
1468         struct sit_net *sitn = net_generic(net, sit_net_id);
1469
1470         iph->version            = 4;
1471         iph->protocol           = IPPROTO_IPV6;
1472         iph->ihl                = 5;
1473         iph->ttl                = 64;
1474
1475         dev_hold(dev);
1476         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1477 }
1478
1479 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1480                           struct netlink_ext_ack *extack)
1481 {
1482         u8 proto;
1483
1484         if (!data || !data[IFLA_IPTUN_PROTO])
1485                 return 0;
1486
1487         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1488         if (!ipip6_valid_ip_proto(proto))
1489                 return -EINVAL;
1490
1491         return 0;
1492 }
1493
1494 static void ipip6_netlink_parms(struct nlattr *data[],
1495                                 struct ip_tunnel_parm *parms,
1496                                 __u32 *fwmark)
1497 {
1498         memset(parms, 0, sizeof(*parms));
1499
1500         parms->iph.version = 4;
1501         parms->iph.protocol = IPPROTO_IPV6;
1502         parms->iph.ihl = 5;
1503         parms->iph.ttl = 64;
1504
1505         if (!data)
1506                 return;
1507
1508         if (data[IFLA_IPTUN_LINK])
1509                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1510
1511         if (data[IFLA_IPTUN_LOCAL])
1512                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1513
1514         if (data[IFLA_IPTUN_REMOTE])
1515                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1516
1517         if (data[IFLA_IPTUN_TTL]) {
1518                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1519                 if (parms->iph.ttl)
1520                         parms->iph.frag_off = htons(IP_DF);
1521         }
1522
1523         if (data[IFLA_IPTUN_TOS])
1524                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1525
1526         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1527                 parms->iph.frag_off = htons(IP_DF);
1528
1529         if (data[IFLA_IPTUN_FLAGS])
1530                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1531
1532         if (data[IFLA_IPTUN_PROTO])
1533                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1534
1535         if (data[IFLA_IPTUN_FWMARK])
1536                 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1537 }
1538
1539 /* This function returns true when ENCAP attributes are present in the nl msg */
1540 static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1541                                       struct ip_tunnel_encap *ipencap)
1542 {
1543         bool ret = false;
1544
1545         memset(ipencap, 0, sizeof(*ipencap));
1546
1547         if (!data)
1548                 return ret;
1549
1550         if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1551                 ret = true;
1552                 ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1553         }
1554
1555         if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1556                 ret = true;
1557                 ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1558         }
1559
1560         if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1561                 ret = true;
1562                 ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1563         }
1564
1565         if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1566                 ret = true;
1567                 ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1568         }
1569
1570         return ret;
1571 }
1572
1573 #ifdef CONFIG_IPV6_SIT_6RD
1574 /* This function returns true when 6RD attributes are present in the nl msg */
1575 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1576                                     struct ip_tunnel_6rd *ip6rd)
1577 {
1578         bool ret = false;
1579         memset(ip6rd, 0, sizeof(*ip6rd));
1580
1581         if (!data)
1582                 return ret;
1583
1584         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1585                 ret = true;
1586                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1587         }
1588
1589         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1590                 ret = true;
1591                 ip6rd->relay_prefix =
1592                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1593         }
1594
1595         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1596                 ret = true;
1597                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1598         }
1599
1600         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1601                 ret = true;
1602                 ip6rd->relay_prefixlen =
1603                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1604         }
1605
1606         return ret;
1607 }
1608 #endif
1609
1610 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1611                          struct nlattr *tb[], struct nlattr *data[],
1612                          struct netlink_ext_ack *extack)
1613 {
1614         struct net *net = dev_net(dev);
1615         struct ip_tunnel *nt;
1616         struct ip_tunnel_encap ipencap;
1617 #ifdef CONFIG_IPV6_SIT_6RD
1618         struct ip_tunnel_6rd ip6rd;
1619 #endif
1620         int err;
1621
1622         nt = netdev_priv(dev);
1623
1624         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1625                 err = ip_tunnel_encap_setup(nt, &ipencap);
1626                 if (err < 0)
1627                         return err;
1628         }
1629
1630         ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1631
1632         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1633                 return -EEXIST;
1634
1635         err = ipip6_tunnel_create(dev);
1636         if (err < 0)
1637                 return err;
1638
1639         if (tb[IFLA_MTU]) {
1640                 u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1641
1642                 if (mtu >= IPV6_MIN_MTU &&
1643                     mtu <= IP6_MAX_MTU - dev->hard_header_len)
1644                         dev->mtu = mtu;
1645         }
1646
1647 #ifdef CONFIG_IPV6_SIT_6RD
1648         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1649                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1650 #endif
1651
1652         return err;
1653 }
1654
1655 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1656                             struct nlattr *data[],
1657                             struct netlink_ext_ack *extack)
1658 {
1659         struct ip_tunnel *t = netdev_priv(dev);
1660         struct ip_tunnel_parm p;
1661         struct ip_tunnel_encap ipencap;
1662         struct net *net = t->net;
1663         struct sit_net *sitn = net_generic(net, sit_net_id);
1664 #ifdef CONFIG_IPV6_SIT_6RD
1665         struct ip_tunnel_6rd ip6rd;
1666 #endif
1667         __u32 fwmark = t->fwmark;
1668         int err;
1669
1670         if (dev == sitn->fb_tunnel_dev)
1671                 return -EINVAL;
1672
1673         if (ipip6_netlink_encap_parms(data, &ipencap)) {
1674                 err = ip_tunnel_encap_setup(t, &ipencap);
1675                 if (err < 0)
1676                         return err;
1677         }
1678
1679         ipip6_netlink_parms(data, &p, &fwmark);
1680
1681         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1682             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1683                 return -EINVAL;
1684
1685         t = ipip6_tunnel_locate(net, &p, 0);
1686
1687         if (t) {
1688                 if (t->dev != dev)
1689                         return -EEXIST;
1690         } else
1691                 t = netdev_priv(dev);
1692
1693         ipip6_tunnel_update(t, &p, fwmark);
1694
1695 #ifdef CONFIG_IPV6_SIT_6RD
1696         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1697                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1698 #endif
1699
1700         return 0;
1701 }
1702
1703 static size_t ipip6_get_size(const struct net_device *dev)
1704 {
1705         return
1706                 /* IFLA_IPTUN_LINK */
1707                 nla_total_size(4) +
1708                 /* IFLA_IPTUN_LOCAL */
1709                 nla_total_size(4) +
1710                 /* IFLA_IPTUN_REMOTE */
1711                 nla_total_size(4) +
1712                 /* IFLA_IPTUN_TTL */
1713                 nla_total_size(1) +
1714                 /* IFLA_IPTUN_TOS */
1715                 nla_total_size(1) +
1716                 /* IFLA_IPTUN_PMTUDISC */
1717                 nla_total_size(1) +
1718                 /* IFLA_IPTUN_FLAGS */
1719                 nla_total_size(2) +
1720                 /* IFLA_IPTUN_PROTO */
1721                 nla_total_size(1) +
1722 #ifdef CONFIG_IPV6_SIT_6RD
1723                 /* IFLA_IPTUN_6RD_PREFIX */
1724                 nla_total_size(sizeof(struct in6_addr)) +
1725                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1726                 nla_total_size(4) +
1727                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1728                 nla_total_size(2) +
1729                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1730                 nla_total_size(2) +
1731 #endif
1732                 /* IFLA_IPTUN_ENCAP_TYPE */
1733                 nla_total_size(2) +
1734                 /* IFLA_IPTUN_ENCAP_FLAGS */
1735                 nla_total_size(2) +
1736                 /* IFLA_IPTUN_ENCAP_SPORT */
1737                 nla_total_size(2) +
1738                 /* IFLA_IPTUN_ENCAP_DPORT */
1739                 nla_total_size(2) +
1740                 /* IFLA_IPTUN_FWMARK */
1741                 nla_total_size(4) +
1742                 0;
1743 }
1744
1745 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1746 {
1747         struct ip_tunnel *tunnel = netdev_priv(dev);
1748         struct ip_tunnel_parm *parm = &tunnel->parms;
1749
1750         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1751             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1752             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1753             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1754             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1755             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1756                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1757             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1758             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags) ||
1759             nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1760                 goto nla_put_failure;
1761
1762 #ifdef CONFIG_IPV6_SIT_6RD
1763         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1764                              &tunnel->ip6rd.prefix) ||
1765             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1766                             tunnel->ip6rd.relay_prefix) ||
1767             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1768                         tunnel->ip6rd.prefixlen) ||
1769             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1770                         tunnel->ip6rd.relay_prefixlen))
1771                 goto nla_put_failure;
1772 #endif
1773
1774         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1775                         tunnel->encap.type) ||
1776             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1777                         tunnel->encap.sport) ||
1778             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1779                         tunnel->encap.dport) ||
1780             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1781                         tunnel->encap.flags))
1782                 goto nla_put_failure;
1783
1784         return 0;
1785
1786 nla_put_failure:
1787         return -EMSGSIZE;
1788 }
1789
1790 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1791         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1792         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1793         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1794         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1795         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1796         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1797         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1798         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1799 #ifdef CONFIG_IPV6_SIT_6RD
1800         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1801         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1802         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1803         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1804 #endif
1805         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1806         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1807         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1808         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1809         [IFLA_IPTUN_FWMARK]             = { .type = NLA_U32 },
1810 };
1811
1812 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1813 {
1814         struct net *net = dev_net(dev);
1815         struct sit_net *sitn = net_generic(net, sit_net_id);
1816
1817         if (dev != sitn->fb_tunnel_dev)
1818                 unregister_netdevice_queue(dev, head);
1819 }
1820
1821 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1822         .kind           = "sit",
1823         .maxtype        = IFLA_IPTUN_MAX,
1824         .policy         = ipip6_policy,
1825         .priv_size      = sizeof(struct ip_tunnel),
1826         .setup          = ipip6_tunnel_setup,
1827         .validate       = ipip6_validate,
1828         .newlink        = ipip6_newlink,
1829         .changelink     = ipip6_changelink,
1830         .get_size       = ipip6_get_size,
1831         .fill_info      = ipip6_fill_info,
1832         .dellink        = ipip6_dellink,
1833         .get_link_net   = ip_tunnel_get_link_net,
1834 };
1835
1836 static struct xfrm_tunnel sit_handler __read_mostly = {
1837         .handler        =       ipip6_rcv,
1838         .err_handler    =       ipip6_err,
1839         .priority       =       1,
1840 };
1841
1842 static struct xfrm_tunnel ipip_handler __read_mostly = {
1843         .handler        =       ipip_rcv,
1844         .err_handler    =       ipip6_err,
1845         .priority       =       2,
1846 };
1847
1848 #if IS_ENABLED(CONFIG_MPLS)
1849 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1850         .handler        =       mplsip_rcv,
1851         .err_handler    =       ipip6_err,
1852         .priority       =       2,
1853 };
1854 #endif
1855
1856 static void __net_exit sit_destroy_tunnels(struct net *net,
1857                                            struct list_head *head)
1858 {
1859         struct sit_net *sitn = net_generic(net, sit_net_id);
1860         struct net_device *dev, *aux;
1861         int prio;
1862
1863         for_each_netdev_safe(net, dev, aux)
1864                 if (dev->rtnl_link_ops == &sit_link_ops)
1865                         unregister_netdevice_queue(dev, head);
1866
1867         for (prio = 1; prio < 4; prio++) {
1868                 int h;
1869                 for (h = 0; h < IP6_SIT_HASH_SIZE; h++) {
1870                         struct ip_tunnel *t;
1871
1872                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1873                         while (t) {
1874                                 /* If dev is in the same netns, it has already
1875                                  * been added to the list by the previous loop.
1876                                  */
1877                                 if (!net_eq(dev_net(t->dev), net))
1878                                         unregister_netdevice_queue(t->dev,
1879                                                                    head);
1880                                 t = rtnl_dereference(t->next);
1881                         }
1882                 }
1883         }
1884 }
1885
1886 static int __net_init sit_init_net(struct net *net)
1887 {
1888         struct sit_net *sitn = net_generic(net, sit_net_id);
1889         struct ip_tunnel *t;
1890         int err;
1891
1892         sitn->tunnels[0] = sitn->tunnels_wc;
1893         sitn->tunnels[1] = sitn->tunnels_l;
1894         sitn->tunnels[2] = sitn->tunnels_r;
1895         sitn->tunnels[3] = sitn->tunnels_r_l;
1896
1897         if (!net_has_fallback_tunnels(net))
1898                 return 0;
1899
1900         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1901                                            NET_NAME_UNKNOWN,
1902                                            ipip6_tunnel_setup);
1903         if (!sitn->fb_tunnel_dev) {
1904                 err = -ENOMEM;
1905                 goto err_alloc_dev;
1906         }
1907         dev_net_set(sitn->fb_tunnel_dev, net);
1908         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1909         /* FB netdevice is special: we have one, and only one per netns.
1910          * Allowing to move it to another netns is clearly unsafe.
1911          */
1912         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1913
1914         err = register_netdev(sitn->fb_tunnel_dev);
1915         if (err)
1916                 goto err_reg_dev;
1917
1918         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1919         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1920
1921         t = netdev_priv(sitn->fb_tunnel_dev);
1922
1923         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1924         return 0;
1925
1926 err_reg_dev:
1927         ipip6_dev_free(sitn->fb_tunnel_dev);
1928         free_netdev(sitn->fb_tunnel_dev);
1929 err_alloc_dev:
1930         return err;
1931 }
1932
1933 static void __net_exit sit_exit_batch_net(struct list_head *net_list)
1934 {
1935         LIST_HEAD(list);
1936         struct net *net;
1937
1938         rtnl_lock();
1939         list_for_each_entry(net, net_list, exit_list)
1940                 sit_destroy_tunnels(net, &list);
1941
1942         unregister_netdevice_many(&list);
1943         rtnl_unlock();
1944 }
1945
1946 static struct pernet_operations sit_net_ops = {
1947         .init = sit_init_net,
1948         .exit_batch = sit_exit_batch_net,
1949         .id   = &sit_net_id,
1950         .size = sizeof(struct sit_net),
1951 };
1952
1953 static void __exit sit_cleanup(void)
1954 {
1955         rtnl_link_unregister(&sit_link_ops);
1956         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1957         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1958 #if IS_ENABLED(CONFIG_MPLS)
1959         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1960 #endif
1961
1962         unregister_pernet_device(&sit_net_ops);
1963         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1964 }
1965
1966 static int __init sit_init(void)
1967 {
1968         int err;
1969
1970         pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1971
1972         err = register_pernet_device(&sit_net_ops);
1973         if (err < 0)
1974                 return err;
1975         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1976         if (err < 0) {
1977                 pr_info("%s: can't register ip6ip4\n", __func__);
1978                 goto xfrm_tunnel_failed;
1979         }
1980         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1981         if (err < 0) {
1982                 pr_info("%s: can't register ip4ip4\n", __func__);
1983                 goto xfrm_tunnel4_failed;
1984         }
1985 #if IS_ENABLED(CONFIG_MPLS)
1986         err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1987         if (err < 0) {
1988                 pr_info("%s: can't register mplsip\n", __func__);
1989                 goto xfrm_tunnel_mpls_failed;
1990         }
1991 #endif
1992         err = rtnl_link_register(&sit_link_ops);
1993         if (err < 0)
1994                 goto rtnl_link_failed;
1995
1996 out:
1997         return err;
1998
1999 rtnl_link_failed:
2000 #if IS_ENABLED(CONFIG_MPLS)
2001         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
2002 xfrm_tunnel_mpls_failed:
2003 #endif
2004         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
2005 xfrm_tunnel4_failed:
2006         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
2007 xfrm_tunnel_failed:
2008         unregister_pernet_device(&sit_net_ops);
2009         goto out;
2010 }
2011
2012 module_init(sit_init);
2013 module_exit(sit_cleanup);
2014 MODULE_LICENSE("GPL");
2015 MODULE_ALIAS_RTNL_LINK("sit");
2016 MODULE_ALIAS_NETDEV("sit0");