net/ipv6/sit.c

   1 /*
   2  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Changes:
  15  * Roger Venning <r.venning@telstra.com>:       6to4 support
  16  * Nate Thompson <nate@thebog.net>:             6to4 support
  17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  18  */
  19
  20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22 #include <linux/module.h>
  23 #include <linux/capability.h>
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/net.h>
  29 #include <linux/in6.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/if_arp.h>
  32 #include <linux/icmp.h>
  33 #include <linux/slab.h>
  34 #include <asm/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 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 int sit_net_id __read_mostly;
  80 struct sit_net {
  81         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  82         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  83         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  84         struct ip_tunnel __rcu *tunnels_wc[1];
  85         struct ip_tunnel __rcu **tunnels[4];
  86
  87         struct net_device *fb_tunnel_dev;
  88 };
  89
  90 /*
  91  * Must be invoked with rcu_read_lock
  92  */
  93 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  94                 struct net_device *dev, __be32 remote, __be32 local)
  95 {
  96         unsigned int h0 = HASH(remote);
  97         unsigned int h1 = HASH(local);
  98         struct ip_tunnel *t;
  99         struct sit_net *sitn = net_generic(net, sit_net_id);
 100
 101         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 102                 if (local == t->parms.iph.saddr &&
 103                     remote == t->parms.iph.daddr &&
 104                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 105                     (t->dev->flags & IFF_UP))
 106                         return t;
 107         }
 108         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 109                 if (remote == t->parms.iph.daddr &&
 110                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 111                     (t->dev->flags & IFF_UP))
 112                         return t;
 113         }
 114         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 115                 if (local == t->parms.iph.saddr &&
 116                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 117                     (t->dev->flags & IFF_UP))
 118                         return t;
 119         }
 120         t = rcu_dereference(sitn->tunnels_wc[0]);
 121         if ((t != NULL) && (t->dev->flags & IFF_UP))
 122                 return t;
 123         return NULL;
 124 }
 125
 126 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 127                 struct ip_tunnel_parm *parms)
 128 {
 129         __be32 remote = parms->iph.daddr;
 130         __be32 local = parms->iph.saddr;
 131         unsigned int h = 0;
 132         int prio = 0;
 133
 134         if (remote) {
 135                 prio |= 2;
 136                 h ^= HASH(remote);
 137         }
 138         if (local) {
 139                 prio |= 1;
 140                 h ^= HASH(local);
 141         }
 142         return &sitn->tunnels[prio][h];
 143 }
 144
 145 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 146                 struct ip_tunnel *t)
 147 {
 148         return __ipip6_bucket(sitn, &t->parms);
 149 }
 150
 151 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 152 {
 153         struct ip_tunnel __rcu **tp;
 154         struct ip_tunnel *iter;
 155
 156         for (tp = ipip6_bucket(sitn, t);
 157              (iter = rtnl_dereference(*tp)) != NULL;
 158              tp = &iter->next) {
 159                 if (t == iter) {
 160                         rcu_assign_pointer(*tp, t->next);
 161                         break;
 162                 }
 163         }
 164 }
 165
 166 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 167 {
 168         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 169
 170         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 171         rcu_assign_pointer(*tp, t);
 172 }
 173
 174 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 175 {
 176 #ifdef CONFIG_IPV6_SIT_6RD
 177         struct ip_tunnel *t = netdev_priv(dev);
 178
 179         if (t->dev == sitn->fb_tunnel_dev) {
 180                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 181                 t->ip6rd.relay_prefix = 0;
 182                 t->ip6rd.prefixlen = 16;
 183                 t->ip6rd.relay_prefixlen = 0;
 184         } else {
 185                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 186                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 187         }
 188 #endif
 189 }
 190
 191 static int ipip6_tunnel_create(struct net_device *dev)
 192 {
 193         struct ip_tunnel *t = netdev_priv(dev);
 194         struct net *net = dev_net(dev);
 195         struct sit_net *sitn = net_generic(net, sit_net_id);
 196         int err;
 197
 198         err = ipip6_tunnel_init(dev);
 199         if (err < 0)
 200                 goto out;
 201         ipip6_tunnel_clone_6rd(dev, sitn);
 202
 203         if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 204                 dev->priv_flags |= IFF_ISATAP;
 205
 206         err = register_netdevice(dev);
 207         if (err < 0)
 208                 goto out;
 209
 210         strcpy(t->parms.name, dev->name);
 211         dev->rtnl_link_ops = &sit_link_ops;
 212
 213         dev_hold(dev);
 214
 215         ipip6_tunnel_link(sitn, t);
 216         return 0;
 217
 218 out:
 219         return err;
 220 }
 221
 222 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 223                 struct ip_tunnel_parm *parms, int create)
 224 {
 225         __be32 remote = parms->iph.daddr;
 226         __be32 local = parms->iph.saddr;
 227         struct ip_tunnel *t, *nt;
 228         struct ip_tunnel __rcu **tp;
 229         struct net_device *dev;
 230         char name[IFNAMSIZ];
 231         struct sit_net *sitn = net_generic(net, sit_net_id);
 232
 233         for (tp = __ipip6_bucket(sitn, parms);
 234             (t = rtnl_dereference(*tp)) != NULL;
 235              tp = &t->next) {
 236                 if (local == t->parms.iph.saddr &&
 237                     remote == t->parms.iph.daddr &&
 238                     parms->link == t->parms.link) {
 239                         if (create)
 240                                 return NULL;
 241                         else
 242                                 return t;
 243                 }
 244         }
 245         if (!create)
 246                 goto failed;
 247
 248         if (parms->name[0])
 249                 strlcpy(name, parms->name, IFNAMSIZ);
 250         else
 251                 strcpy(name, "sit%d");
 252
 253         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 254                            ipip6_tunnel_setup);
 255         if (dev == NULL)
 256                 return NULL;
 257
 258         dev_net_set(dev, net);
 259
 260         nt = netdev_priv(dev);
 261
 262         nt->parms = *parms;
 263         if (ipip6_tunnel_create(dev) < 0)
 264                 goto failed_free;
 265
 266         return nt;
 267
 268 failed_free:
 269         ipip6_dev_free(dev);
 270 failed:
 271         return NULL;
 272 }
 273
 274 #define for_each_prl_rcu(start)                 \
 275         for (prl = rcu_dereference(start);      \
 276              prl;                               \
 277              prl = rcu_dereference(prl->next))
 278
 279 static struct ip_tunnel_prl_entry *
 280 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 281 {
 282         struct ip_tunnel_prl_entry *prl;
 283
 284         for_each_prl_rcu(t->prl)
 285                 if (prl->addr == addr)
 286                         break;
 287         return prl;
 288
 289 }
 290
 291 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 292                                 struct ip_tunnel_prl __user *a)
 293 {
 294         struct ip_tunnel_prl kprl, *kp;
 295         struct ip_tunnel_prl_entry *prl;
 296         unsigned int cmax, c = 0, ca, len;
 297         int ret = 0;
 298
 299         if (copy_from_user(&kprl, a, sizeof(kprl)))
 300                 return -EFAULT;
 301         cmax = kprl.datalen / sizeof(kprl);
 302         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 303                 cmax = 1;
 304
 305         /* For simple GET or for root users,
 306          * we try harder to allocate.
 307          */
 308         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 309                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 310                 NULL;
 311
 312         rcu_read_lock();
 313
 314         ca = t->prl_count < cmax ? t->prl_count : cmax;
 315
 316         if (!kp) {
 317                 /* We don't try hard to allocate much memory for
 318                  * non-root users.
 319                  * For root users, retry allocating enough memory for
 320                  * the answer.
 321                  */
 322                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 323                 if (!kp) {
 324                         ret = -ENOMEM;
 325                         goto out;
 326                 }
 327         }
 328
 329         c = 0;
 330         for_each_prl_rcu(t->prl) {
 331                 if (c >= cmax)
 332                         break;
 333                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 334                         continue;
 335                 kp[c].addr = prl->addr;
 336                 kp[c].flags = prl->flags;
 337                 c++;
 338                 if (kprl.addr != htonl(INADDR_ANY))
 339                         break;
 340         }
 341 out:
 342         rcu_read_unlock();
 343
 344         len = sizeof(*kp) * c;
 345         ret = 0;
 346         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 347                 ret = -EFAULT;
 348
 349         kfree(kp);
 350
 351         return ret;
 352 }
 353
 354 static int
 355 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 356 {
 357         struct ip_tunnel_prl_entry *p;
 358         int err = 0;
 359
 360         if (a->addr == htonl(INADDR_ANY))
 361                 return -EINVAL;
 362
 363         ASSERT_RTNL();
 364
 365         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 366                 if (p->addr == a->addr) {
 367                         if (chg) {
 368                                 p->flags = a->flags;
 369                                 goto out;
 370                         }
 371                         err = -EEXIST;
 372                         goto out;
 373                 }
 374         }
 375
 376         if (chg) {
 377                 err = -ENXIO;
 378                 goto out;
 379         }
 380
 381         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 382         if (!p) {
 383                 err = -ENOBUFS;
 384                 goto out;
 385         }
 386
 387         p->next = t->prl;
 388         p->addr = a->addr;
 389         p->flags = a->flags;
 390         t->prl_count++;
 391         rcu_assign_pointer(t->prl, p);
 392 out:
 393         return err;
 394 }
 395
 396 static void prl_list_destroy_rcu(struct rcu_head *head)
 397 {
 398         struct ip_tunnel_prl_entry *p, *n;
 399
 400         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 401         do {
 402                 n = rcu_dereference_protected(p->next, 1);
 403                 kfree(p);
 404                 p = n;
 405         } while (p);
 406 }
 407
 408 static int
 409 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 410 {
 411         struct ip_tunnel_prl_entry *x;
 412         struct ip_tunnel_prl_entry __rcu **p;
 413         int err = 0;
 414
 415         ASSERT_RTNL();
 416
 417         if (a && a->addr != htonl(INADDR_ANY)) {
 418                 for (p = &t->prl;
 419                      (x = rtnl_dereference(*p)) != NULL;
 420                      p = &x->next) {
 421                         if (x->addr == a->addr) {
 422                                 *p = x->next;
 423                                 kfree_rcu(x, rcu_head);
 424                                 t->prl_count--;
 425                                 goto out;
 426                         }
 427                 }
 428                 err = -ENXIO;
 429         } else {
 430                 x = rtnl_dereference(t->prl);
 431                 if (x) {
 432                         t->prl_count = 0;
 433                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 434                         t->prl = NULL;
 435                 }
 436         }
 437 out:
 438         return err;
 439 }
 440
 441 static int
 442 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 443 {
 444         struct ip_tunnel_prl_entry *p;
 445         int ok = 1;
 446
 447         rcu_read_lock();
 448         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 449         if (p) {
 450                 if (p->flags & PRL_DEFAULT)
 451                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 452                 else
 453                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 454         } else {
 455                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 456
 457                 if (ipv6_addr_is_isatap(addr6) &&
 458                     (addr6->s6_addr32[3] == iph->saddr) &&
 459                     ipv6_chk_prefix(addr6, t->dev))
 460                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 461                 else
 462                         ok = 0;
 463         }
 464         rcu_read_unlock();
 465         return ok;
 466 }
 467
 468 static void ipip6_tunnel_uninit(struct net_device *dev)
 469 {
 470         struct ip_tunnel *tunnel = netdev_priv(dev);
 471         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 472
 473         if (dev == sitn->fb_tunnel_dev) {
 474                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 475         } else {
 476                 ipip6_tunnel_unlink(sitn, tunnel);
 477                 ipip6_tunnel_del_prl(tunnel, NULL);
 478         }
 479         ip_tunnel_dst_reset_all(tunnel);
 480         dev_put(dev);
 481 }
 482
 483 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
 484  * if sufficient data bytes are available
 485  */
 486 static int ipip6_err_gen_icmpv6_unreach(struct sk_buff *skb)
 487 {
 488         const struct iphdr *iph = (const struct iphdr *) skb->data;
 489         struct rt6_info *rt;
 490         struct sk_buff *skb2;
 491
 492         if (!pskb_may_pull(skb, iph->ihl * 4 + sizeof(struct ipv6hdr) + 8))
 493                 return 1;
 494
 495         skb2 = skb_clone(skb, GFP_ATOMIC);
 496
 497         if (!skb2)
 498                 return 1;
 499
 500         skb_dst_drop(skb2);
 501         skb_pull(skb2, iph->ihl * 4);
 502         skb_reset_network_header(skb2);
 503
 504         rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);
 505
 506         if (rt && rt->dst.dev)
 507                 skb2->dev = rt->dst.dev;
 508
 509         icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 510
 511         if (rt)
 512                 ip6_rt_put(rt);
 513
 514         kfree_skb(skb2);
 515
 516         return 0;
 517 }
 518
 519 static int ipip6_err(struct sk_buff *skb, u32 info)
 520 {
 521         const struct iphdr *iph = (const struct iphdr *)skb->data;
 522         const int type = icmp_hdr(skb)->type;
 523         const int code = icmp_hdr(skb)->code;
 524         struct ip_tunnel *t;
 525         int err;
 526
 527         switch (type) {
 528         default:
 529         case ICMP_PARAMETERPROB:
 530                 return 0;
 531
 532         case ICMP_DEST_UNREACH:
 533                 switch (code) {
 534                 case ICMP_SR_FAILED:
 535                         /* Impossible event. */
 536                         return 0;
 537                 default:
 538                         /* All others are translated to HOST_UNREACH.
 539                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 540                            I believe they are just ether pollution. --ANK
 541                          */
 542                         break;
 543                 }
 544                 break;
 545         case ICMP_TIME_EXCEEDED:
 546                 if (code != ICMP_EXC_TTL)
 547                         return 0;
 548                 break;
 549         case ICMP_REDIRECT:
 550                 break;
 551         }
 552
 553         err = -ENOENT;
 554
 555         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 556                                 skb->dev,
 557                                 iph->daddr,
 558                                 iph->saddr);
 559         if (t == NULL)
 560                 goto out;
 561
 562         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 563                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 564                                  t->parms.link, 0, IPPROTO_IPV6, 0);
 565                 err = 0;
 566                 goto out;
 567         }
 568         if (type == ICMP_REDIRECT) {
 569                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
 570                               IPPROTO_IPV6, 0);
 571                 err = 0;
 572                 goto out;
 573         }
 574
 575         if (t->parms.iph.daddr == 0)
 576                 goto out;
 577
 578         err = 0;
 579         if (!ipip6_err_gen_icmpv6_unreach(skb))
 580                 goto out;
 581
 582         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 583                 goto out;
 584
 585         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 586                 t->err_count++;
 587         else
 588                 t->err_count = 1;
 589         t->err_time = jiffies;
 590 out:
 591         return err;
 592 }
 593
 594 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 595                                   const struct in6_addr *v6addr)
 596 {
 597         __be32 v4embed = 0;
 598         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 599                 return true;
 600         return false;
 601 }
 602
 603 /* Checks if an address matches an address on the tunnel interface.
 604  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 605  * Long story:
 606  * This function is called after we considered the packet as spoofed
 607  * in is_spoofed_6rd.
 608  * We may have a router that is doing NAT for proto 41 packets
 609  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 610  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 611  * function will return true, dropping the packet.
 612  * But, we can still check if is spoofed against the IP
 613  * addresses associated with the interface.
 614  */
 615 static bool only_dnatted(const struct ip_tunnel *tunnel,
 616         const struct in6_addr *v6dst)
 617 {
 618         int prefix_len;
 619
 620 #ifdef CONFIG_IPV6_SIT_6RD
 621         prefix_len = tunnel->ip6rd.prefixlen + 32
 622                 - tunnel->ip6rd.relay_prefixlen;
 623 #else
 624         prefix_len = 48;
 625 #endif
 626         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 627 }
 628
 629 /* Returns true if a packet is spoofed */
 630 static bool packet_is_spoofed(struct sk_buff *skb,
 631                               const struct iphdr *iph,
 632                               struct ip_tunnel *tunnel)
 633 {
 634         const struct ipv6hdr *ipv6h;
 635
 636         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 637                 if (!isatap_chksrc(skb, iph, tunnel))
 638                         return true;
 639
 640                 return false;
 641         }
 642
 643         if (tunnel->dev->flags & IFF_POINTOPOINT)
 644                 return false;
 645
 646         ipv6h = ipv6_hdr(skb);
 647
 648         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 649                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 650                                      &iph->saddr, &ipv6h->saddr,
 651                                      &iph->daddr, &ipv6h->daddr);
 652                 return true;
 653         }
 654
 655         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 656                 return false;
 657
 658         if (only_dnatted(tunnel, &ipv6h->daddr))
 659                 return false;
 660
 661         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 662                              &iph->saddr, &ipv6h->saddr,
 663                              &iph->daddr, &ipv6h->daddr);
 664         return true;
 665 }
 666
 667 static int ipip6_rcv(struct sk_buff *skb)
 668 {
 669         const struct iphdr *iph = ip_hdr(skb);
 670         struct ip_tunnel *tunnel;
 671         int err;
 672
 673         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 674                                      iph->saddr, iph->daddr);
 675         if (tunnel != NULL) {
 676                 struct pcpu_sw_netstats *tstats;
 677
 678                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 679                     tunnel->parms.iph.protocol != 0)
 680                         goto out;
 681
 682                 skb->mac_header = skb->network_header;
 683                 skb_reset_network_header(skb);
 684                 IPCB(skb)->flags = 0;
 685                 skb->protocol = htons(ETH_P_IPV6);
 686
 687                 if (packet_is_spoofed(skb, iph, tunnel)) {
 688                         tunnel->dev->stats.rx_errors++;
 689                         goto out;
 690                 }
 691
 692                 __skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
 693
 694                 err = IP_ECN_decapsulate(iph, skb);
 695                 if (unlikely(err)) {
 696                         if (log_ecn_error)
 697                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 698                                                      &iph->saddr, iph->tos);
 699                         if (err > 1) {
 700                                 ++tunnel->dev->stats.rx_frame_errors;
 701                                 ++tunnel->dev->stats.rx_errors;
 702                                 goto out;
 703                         }
 704                 }
 705
 706                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 707                 u64_stats_update_begin(&tstats->syncp);
 708                 tstats->rx_packets++;
 709                 tstats->rx_bytes += skb->len;
 710                 u64_stats_update_end(&tstats->syncp);
 711
 712                 netif_rx(skb);
 713
 714                 return 0;
 715         }
 716
 717         /* no tunnel matched,  let upstream know, ipsec may handle it */
 718         return 1;
 719 out:
 720         kfree_skb(skb);
 721         return 0;
 722 }
 723
 724 static const struct tnl_ptk_info tpi = {
 725         /* no tunnel info required for ipip. */
 726         .proto = htons(ETH_P_IP),
 727 };
 728
 729 static int ipip_rcv(struct sk_buff *skb)
 730 {
 731         const struct iphdr *iph;
 732         struct ip_tunnel *tunnel;
 733
 734         iph = ip_hdr(skb);
 735         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 736                                      iph->saddr, iph->daddr);
 737         if (tunnel != NULL) {
 738                 if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 739                     tunnel->parms.iph.protocol != 0)
 740                         goto drop;
 741
 742                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 743                         goto drop;
 744                 if (iptunnel_pull_header(skb, 0, tpi.proto))
 745                         goto drop;
 746                 return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
 747         }
 748
 749         return 1;
 750
 751 drop:
 752         kfree_skb(skb);
 753         return 0;
 754 }
 755
 756 /*
 757  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 758  * stores the embedded IPv4 address in v4dst and returns true.
 759  */
 760 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 761                       __be32 *v4dst)
 762 {
 763 #ifdef CONFIG_IPV6_SIT_6RD
 764         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 765                               tunnel->ip6rd.prefixlen)) {
 766                 unsigned int pbw0, pbi0;
 767                 int pbi1;
 768                 u32 d;
 769
 770                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 771                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 772
 773                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 774                     tunnel->ip6rd.relay_prefixlen;
 775
 776                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 777                 if (pbi1 > 0)
 778                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 779                              (32 - pbi1);
 780
 781                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 782                 return true;
 783         }
 784 #else
 785         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 786                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 787                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 788                 return true;
 789         }
 790 #endif
 791         return false;
 792 }
 793
 794 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 795                              const struct in6_addr *v6dst)
 796 {
 797         __be32 dst = 0;
 798         check_6rd(tunnel, v6dst, &dst);
 799         return dst;
 800 }
 801
 802 /*
 803  *      This function assumes it is being called from dev_queue_xmit()
 804  *      and that skb is filled properly by that function.
 805  */
 806
 807 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 808                                      struct net_device *dev)
 809 {
 810         struct ip_tunnel *tunnel = netdev_priv(dev);
 811         const struct iphdr  *tiph = &tunnel->parms.iph;
 812         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 813         u8     tos = tunnel->parms.iph.tos;
 814         __be16 df = tiph->frag_off;
 815         struct rtable *rt;                      /* Route to the other host */
 816         struct net_device *tdev;                /* Device to other host */
 817         unsigned int max_headroom;              /* The extra header space needed */
 818         __be32 dst = tiph->daddr;
 819         struct flowi4 fl4;
 820         int    mtu;
 821         const struct in6_addr *addr6;
 822         int addr_type;
 823         u8 ttl;
 824         int err;
 825
 826         if (skb->protocol != htons(ETH_P_IPV6))
 827                 goto tx_error;
 828
 829         if (tos == 1)
 830                 tos = ipv6_get_dsfield(iph6);
 831
 832         /* ISATAP (RFC4214) - must come before 6to4 */
 833         if (dev->priv_flags & IFF_ISATAP) {
 834                 struct neighbour *neigh = NULL;
 835                 bool do_tx_error = false;
 836
 837                 if (skb_dst(skb))
 838                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 839
 840                 if (neigh == NULL) {
 841                         net_dbg_ratelimited("nexthop == NULL\n");
 842                         goto tx_error;
 843                 }
 844
 845                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 846                 addr_type = ipv6_addr_type(addr6);
 847
 848                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 849                      ipv6_addr_is_isatap(addr6))
 850                         dst = addr6->s6_addr32[3];
 851                 else
 852                         do_tx_error = true;
 853
 854                 neigh_release(neigh);
 855                 if (do_tx_error)
 856                         goto tx_error;
 857         }
 858
 859         if (!dst)
 860                 dst = try_6rd(tunnel, &iph6->daddr);
 861
 862         if (!dst) {
 863                 struct neighbour *neigh = NULL;
 864                 bool do_tx_error = false;
 865
 866                 if (skb_dst(skb))
 867                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 868
 869                 if (neigh == NULL) {
 870                         net_dbg_ratelimited("nexthop == NULL\n");
 871                         goto tx_error;
 872                 }
 873
 874                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 875                 addr_type = ipv6_addr_type(addr6);
 876
 877                 if (addr_type == IPV6_ADDR_ANY) {
 878                         addr6 = &ipv6_hdr(skb)->daddr;
 879                         addr_type = ipv6_addr_type(addr6);
 880                 }
 881
 882                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 883                         dst = addr6->s6_addr32[3];
 884                 else
 885                         do_tx_error = true;
 886
 887                 neigh_release(neigh);
 888                 if (do_tx_error)
 889                         goto tx_error;
 890         }
 891
 892         rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 893                                    dst, tiph->saddr,
 894                                    0, 0,
 895                                    IPPROTO_IPV6, RT_TOS(tos),
 896                                    tunnel->parms.link);
 897         if (IS_ERR(rt)) {
 898                 dev->stats.tx_carrier_errors++;
 899                 goto tx_error_icmp;
 900         }
 901         if (rt->rt_type != RTN_UNICAST) {
 902                 ip_rt_put(rt);
 903                 dev->stats.tx_carrier_errors++;
 904                 goto tx_error_icmp;
 905         }
 906         tdev = rt->dst.dev;
 907
 908         if (tdev == dev) {
 909                 ip_rt_put(rt);
 910                 dev->stats.collisions++;
 911                 goto tx_error;
 912         }
 913
 914         if (df) {
 915                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 916
 917                 if (mtu < 68) {
 918                         dev->stats.collisions++;
 919                         ip_rt_put(rt);
 920                         goto tx_error;
 921                 }
 922
 923                 if (mtu < IPV6_MIN_MTU) {
 924                         mtu = IPV6_MIN_MTU;
 925                         df = 0;
 926                 }
 927
 928                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 929                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 930
 931                 if (skb->len > mtu && !skb_is_gso(skb)) {
 932                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 933                         ip_rt_put(rt);
 934                         goto tx_error;
 935                 }
 936         }
 937
 938         if (tunnel->err_count > 0) {
 939                 if (time_before(jiffies,
 940                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 941                         tunnel->err_count--;
 942                         dst_link_failure(skb);
 943                 } else
 944                         tunnel->err_count = 0;
 945         }
 946
 947         /*
 948          * Okay, now see if we can stuff it in the buffer as-is.
 949          */
 950         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 951
 952         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 953             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 954                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 955                 if (!new_skb) {
 956                         ip_rt_put(rt);
 957                         dev->stats.tx_dropped++;
 958                         kfree_skb(skb);
 959                         return NETDEV_TX_OK;
 960                 }
 961                 if (skb->sk)
 962                         skb_set_owner_w(new_skb, skb->sk);
 963                 dev_kfree_skb(skb);
 964                 skb = new_skb;
 965                 iph6 = ipv6_hdr(skb);
 966         }
 967         ttl = tiph->ttl;
 968         if (ttl == 0)
 969                 ttl = iph6->hop_limit;
 970         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 971
 972         skb = iptunnel_handle_offloads(skb, false, SKB_GSO_SIT);
 973         if (IS_ERR(skb)) {
 974                 ip_rt_put(rt);
 975                 goto out;
 976         }
 977
 978         err = iptunnel_xmit(skb->sk, rt, skb, fl4.saddr, fl4.daddr,
 979                             IPPROTO_IPV6, tos, ttl, df,
 980                             !net_eq(tunnel->net, dev_net(dev)));
 981         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 982         return NETDEV_TX_OK;
 983
 984 tx_error_icmp:
 985         dst_link_failure(skb);
 986 tx_error:
 987         kfree_skb(skb);
 988 out:
 989         dev->stats.tx_errors++;
 990         return NETDEV_TX_OK;
 991 }
 992
 993 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 994 {
 995         struct ip_tunnel *tunnel = netdev_priv(dev);
 996         const struct iphdr  *tiph = &tunnel->parms.iph;
 997
 998         skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP);
 999         if (IS_ERR(skb))
1000                 goto out;
1001
1002         ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
1003         return NETDEV_TX_OK;
1004 out:
1005         dev->stats.tx_errors++;
1006         return NETDEV_TX_OK;
1007 }
1008
1009 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1010                                    struct net_device *dev)
1011 {
1012         switch (skb->protocol) {
1013         case htons(ETH_P_IP):
1014                 ipip_tunnel_xmit(skb, dev);
1015                 break;
1016         case htons(ETH_P_IPV6):
1017                 ipip6_tunnel_xmit(skb, dev);
1018                 break;
1019         default:
1020                 goto tx_err;
1021         }
1022
1023         return NETDEV_TX_OK;
1024
1025 tx_err:
1026         dev->stats.tx_errors++;
1027         kfree_skb(skb);
1028         return NETDEV_TX_OK;
1029
1030 }
1031
1032 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1033 {
1034         struct net_device *tdev = NULL;
1035         struct ip_tunnel *tunnel;
1036         const struct iphdr *iph;
1037         struct flowi4 fl4;
1038
1039         tunnel = netdev_priv(dev);
1040         iph = &tunnel->parms.iph;
1041
1042         if (iph->daddr) {
1043                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1044                                                           NULL,
1045                                                           iph->daddr, iph->saddr,
1046                                                           0, 0,
1047                                                           IPPROTO_IPV6,
1048                                                           RT_TOS(iph->tos),
1049                                                           tunnel->parms.link);
1050
1051                 if (!IS_ERR(rt)) {
1052                         tdev = rt->dst.dev;
1053                         ip_rt_put(rt);
1054                 }
1055                 dev->flags |= IFF_POINTOPOINT;
1056         }
1057
1058         if (!tdev && tunnel->parms.link)
1059                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1060
1061         if (tdev) {
1062                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1063                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
1064                 if (dev->mtu < IPV6_MIN_MTU)
1065                         dev->mtu = IPV6_MIN_MTU;
1066         }
1067         dev->iflink = tunnel->parms.link;
1068 }
1069
1070 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1071 {
1072         struct net *net = t->net;
1073         struct sit_net *sitn = net_generic(net, sit_net_id);
1074
1075         ipip6_tunnel_unlink(sitn, t);
1076         synchronize_net();
1077         t->parms.iph.saddr = p->iph.saddr;
1078         t->parms.iph.daddr = p->iph.daddr;
1079         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1080         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1081         ipip6_tunnel_link(sitn, t);
1082         t->parms.iph.ttl = p->iph.ttl;
1083         t->parms.iph.tos = p->iph.tos;
1084         if (t->parms.link != p->link) {
1085                 t->parms.link = p->link;
1086                 ipip6_tunnel_bind_dev(t->dev);
1087         }
1088         ip_tunnel_dst_reset_all(t);
1089         netdev_state_change(t->dev);
1090 }
1091
1092 #ifdef CONFIG_IPV6_SIT_6RD
1093 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1094                                    struct ip_tunnel_6rd *ip6rd)
1095 {
1096         struct in6_addr prefix;
1097         __be32 relay_prefix;
1098
1099         if (ip6rd->relay_prefixlen > 32 ||
1100             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1101                 return -EINVAL;
1102
1103         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1104         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1105                 return -EINVAL;
1106         if (ip6rd->relay_prefixlen)
1107                 relay_prefix = ip6rd->relay_prefix &
1108                                htonl(0xffffffffUL <<
1109                                      (32 - ip6rd->relay_prefixlen));
1110         else
1111                 relay_prefix = 0;
1112         if (relay_prefix != ip6rd->relay_prefix)
1113                 return -EINVAL;
1114
1115         t->ip6rd.prefix = prefix;
1116         t->ip6rd.relay_prefix = relay_prefix;
1117         t->ip6rd.prefixlen = ip6rd->prefixlen;
1118         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1119         ip_tunnel_dst_reset_all(t);
1120         netdev_state_change(t->dev);
1121         return 0;
1122 }
1123 #endif
1124
1125 static int
1126 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1127 {
1128         int err = 0;
1129         struct ip_tunnel_parm p;
1130         struct ip_tunnel_prl prl;
1131         struct ip_tunnel *t = netdev_priv(dev);
1132         struct net *net = t->net;
1133         struct sit_net *sitn = net_generic(net, sit_net_id);
1134 #ifdef CONFIG_IPV6_SIT_6RD
1135         struct ip_tunnel_6rd ip6rd;
1136 #endif
1137
1138         switch (cmd) {
1139         case SIOCGETTUNNEL:
1140 #ifdef CONFIG_IPV6_SIT_6RD
1141         case SIOCGET6RD:
1142 #endif
1143                 if (dev == sitn->fb_tunnel_dev) {
1144                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1145                                 err = -EFAULT;
1146                                 break;
1147                         }
1148                         t = ipip6_tunnel_locate(net, &p, 0);
1149                         if (t == NULL)
1150                                 t = netdev_priv(dev);
1151                 }
1152
1153                 err = -EFAULT;
1154                 if (cmd == SIOCGETTUNNEL) {
1155                         memcpy(&p, &t->parms, sizeof(p));
1156                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1157                                          sizeof(p)))
1158                                 goto done;
1159 #ifdef CONFIG_IPV6_SIT_6RD
1160                 } else {
1161                         ip6rd.prefix = t->ip6rd.prefix;
1162                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1163                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1164                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1165                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1166                                          sizeof(ip6rd)))
1167                                 goto done;
1168 #endif
1169                 }
1170                 err = 0;
1171                 break;
1172
1173         case SIOCADDTUNNEL:
1174         case SIOCCHGTUNNEL:
1175                 err = -EPERM;
1176                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1177                         goto done;
1178
1179                 err = -EFAULT;
1180                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1181                         goto done;
1182
1183                 err = -EINVAL;
1184                 if (p.iph.protocol != IPPROTO_IPV6 &&
1185                     p.iph.protocol != IPPROTO_IPIP &&
1186                     p.iph.protocol != 0)
1187                         goto done;
1188                 if (p.iph.version != 4 ||
1189                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1190                         goto done;
1191                 if (p.iph.ttl)
1192                         p.iph.frag_off |= htons(IP_DF);
1193
1194                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1195
1196                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1197                         if (t != NULL) {
1198                                 if (t->dev != dev) {
1199                                         err = -EEXIST;
1200                                         break;
1201                                 }
1202                         } else {
1203                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1204                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1205                                         err = -EINVAL;
1206                                         break;
1207                                 }
1208                                 t = netdev_priv(dev);
1209                         }
1210
1211                         ipip6_tunnel_update(t, &p);
1212                 }
1213
1214                 if (t) {
1215                         err = 0;
1216                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1217                                 err = -EFAULT;
1218                 } else
1219                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1220                 break;
1221
1222         case SIOCDELTUNNEL:
1223                 err = -EPERM;
1224                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1225                         goto done;
1226
1227                 if (dev == sitn->fb_tunnel_dev) {
1228                         err = -EFAULT;
1229                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1230                                 goto done;
1231                         err = -ENOENT;
1232                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1233                                 goto done;
1234                         err = -EPERM;
1235                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1236                                 goto done;
1237                         dev = t->dev;
1238                 }
1239                 unregister_netdevice(dev);
1240                 err = 0;
1241                 break;
1242
1243         case SIOCGETPRL:
1244                 err = -EINVAL;
1245                 if (dev == sitn->fb_tunnel_dev)
1246                         goto done;
1247                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1248                 break;
1249
1250         case SIOCADDPRL:
1251         case SIOCDELPRL:
1252         case SIOCCHGPRL:
1253                 err = -EPERM;
1254                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1255                         goto done;
1256                 err = -EINVAL;
1257                 if (dev == sitn->fb_tunnel_dev)
1258                         goto done;
1259                 err = -EFAULT;
1260                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1261                         goto done;
1262
1263                 switch (cmd) {
1264                 case SIOCDELPRL:
1265                         err = ipip6_tunnel_del_prl(t, &prl);
1266                         break;
1267                 case SIOCADDPRL:
1268                 case SIOCCHGPRL:
1269                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1270                         break;
1271                 }
1272                 ip_tunnel_dst_reset_all(t);
1273                 netdev_state_change(dev);
1274                 break;
1275
1276 #ifdef CONFIG_IPV6_SIT_6RD
1277         case SIOCADD6RD:
1278         case SIOCCHG6RD:
1279         case SIOCDEL6RD:
1280                 err = -EPERM;
1281                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1282                         goto done;
1283
1284                 err = -EFAULT;
1285                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1286                                    sizeof(ip6rd)))
1287                         goto done;
1288
1289                 if (cmd != SIOCDEL6RD) {
1290                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1291                         if (err < 0)
1292                                 goto done;
1293                 } else
1294                         ipip6_tunnel_clone_6rd(dev, sitn);
1295
1296                 err = 0;
1297                 break;
1298 #endif
1299
1300         default:
1301                 err = -EINVAL;
1302         }
1303
1304 done:
1305         return err;
1306 }
1307
1308 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1309 {
1310         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1311                 return -EINVAL;
1312         dev->mtu = new_mtu;
1313         return 0;
1314 }
1315
1316 static const struct net_device_ops ipip6_netdev_ops = {
1317         .ndo_uninit     = ipip6_tunnel_uninit,
1318         .ndo_start_xmit = sit_tunnel_xmit,
1319         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1320         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1321         .ndo_get_stats64 = ip_tunnel_get_stats64,
1322 };
1323
1324 static void ipip6_dev_free(struct net_device *dev)
1325 {
1326         struct ip_tunnel *tunnel = netdev_priv(dev);
1327
1328         free_percpu(tunnel->dst_cache);
1329         free_percpu(dev->tstats);
1330         free_netdev(dev);
1331 }
1332
1333 #define SIT_FEATURES (NETIF_F_SG           | \
1334                       NETIF_F_FRAGLIST     | \
1335                       NETIF_F_HIGHDMA      | \
1336                       NETIF_F_GSO_SOFTWARE | \
1337                       NETIF_F_HW_CSUM)
1338
1339 static void ipip6_tunnel_setup(struct net_device *dev)
1340 {
1341         dev->netdev_ops         = &ipip6_netdev_ops;
1342         dev->destructor         = ipip6_dev_free;
1343
1344         dev->type               = ARPHRD_SIT;
1345         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1346         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1347         dev->flags              = IFF_NOARP;
1348         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1349         dev->iflink             = 0;
1350         dev->addr_len           = 4;
1351         dev->features           |= NETIF_F_LLTX;
1352         dev->features           |= SIT_FEATURES;
1353         dev->hw_features        |= SIT_FEATURES;
1354 }
1355
1356 static int ipip6_tunnel_init(struct net_device *dev)
1357 {
1358         struct ip_tunnel *tunnel = netdev_priv(dev);
1359
1360         tunnel->dev = dev;
1361         tunnel->net = dev_net(dev);
1362
1363         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1364         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1365
1366         ipip6_tunnel_bind_dev(dev);
1367         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1368         if (!dev->tstats)
1369                 return -ENOMEM;
1370
1371         tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
1372         if (!tunnel->dst_cache) {
1373                 free_percpu(dev->tstats);
1374                 return -ENOMEM;
1375         }
1376
1377         return 0;
1378 }
1379
1380 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1381 {
1382         struct ip_tunnel *tunnel = netdev_priv(dev);
1383         struct iphdr *iph = &tunnel->parms.iph;
1384         struct net *net = dev_net(dev);
1385         struct sit_net *sitn = net_generic(net, sit_net_id);
1386
1387         tunnel->dev = dev;
1388         tunnel->net = dev_net(dev);
1389         strcpy(tunnel->parms.name, dev->name);
1390
1391         iph->version            = 4;
1392         iph->protocol           = IPPROTO_IPV6;
1393         iph->ihl                = 5;
1394         iph->ttl                = 64;
1395
1396         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1397         if (!dev->tstats)
1398                 return -ENOMEM;
1399
1400         tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
1401         if (!tunnel->dst_cache) {
1402                 free_percpu(dev->tstats);
1403                 return -ENOMEM;
1404         }
1405
1406         dev_hold(dev);
1407         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1408         return 0;
1409 }
1410
1411 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1412 {
1413         u8 proto;
1414
1415         if (!data || !data[IFLA_IPTUN_PROTO])
1416                 return 0;
1417
1418         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1419         if (proto != IPPROTO_IPV6 &&
1420             proto != IPPROTO_IPIP &&
1421             proto != 0)
1422                 return -EINVAL;
1423
1424         return 0;
1425 }
1426
1427 static void ipip6_netlink_parms(struct nlattr *data[],
1428                                 struct ip_tunnel_parm *parms)
1429 {
1430         memset(parms, 0, sizeof(*parms));
1431
1432         parms->iph.version = 4;
1433         parms->iph.protocol = IPPROTO_IPV6;
1434         parms->iph.ihl = 5;
1435         parms->iph.ttl = 64;
1436
1437         if (!data)
1438                 return;
1439
1440         if (data[IFLA_IPTUN_LINK])
1441                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1442
1443         if (data[IFLA_IPTUN_LOCAL])
1444                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1445
1446         if (data[IFLA_IPTUN_REMOTE])
1447                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1448
1449         if (data[IFLA_IPTUN_TTL]) {
1450                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1451                 if (parms->iph.ttl)
1452                         parms->iph.frag_off = htons(IP_DF);
1453         }
1454
1455         if (data[IFLA_IPTUN_TOS])
1456                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1457
1458         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1459                 parms->iph.frag_off = htons(IP_DF);
1460
1461         if (data[IFLA_IPTUN_FLAGS])
1462                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1463
1464         if (data[IFLA_IPTUN_PROTO])
1465                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1466
1467 }
1468
1469 #ifdef CONFIG_IPV6_SIT_6RD
1470 /* This function returns true when 6RD attributes are present in the nl msg */
1471 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1472                                     struct ip_tunnel_6rd *ip6rd)
1473 {
1474         bool ret = false;
1475         memset(ip6rd, 0, sizeof(*ip6rd));
1476
1477         if (!data)
1478                 return ret;
1479
1480         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1481                 ret = true;
1482                 nla_memcpy(&ip6rd->prefix, data[IFLA_IPTUN_6RD_PREFIX],
1483                            sizeof(struct in6_addr));
1484         }
1485
1486         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1487                 ret = true;
1488                 ip6rd->relay_prefix =
1489                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1490         }
1491
1492         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1493                 ret = true;
1494                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1495         }
1496
1497         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1498                 ret = true;
1499                 ip6rd->relay_prefixlen =
1500                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1501         }
1502
1503         return ret;
1504 }
1505 #endif
1506
1507 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1508                          struct nlattr *tb[], struct nlattr *data[])
1509 {
1510         struct net *net = dev_net(dev);
1511         struct ip_tunnel *nt;
1512 #ifdef CONFIG_IPV6_SIT_6RD
1513         struct ip_tunnel_6rd ip6rd;
1514 #endif
1515         int err;
1516
1517         nt = netdev_priv(dev);
1518         ipip6_netlink_parms(data, &nt->parms);
1519
1520         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1521                 return -EEXIST;
1522
1523         err = ipip6_tunnel_create(dev);
1524         if (err < 0)
1525                 return err;
1526
1527 #ifdef CONFIG_IPV6_SIT_6RD
1528         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1529                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1530 #endif
1531
1532         return err;
1533 }
1534
1535 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1536                           struct nlattr *data[])
1537 {
1538         struct ip_tunnel *t = netdev_priv(dev);
1539         struct ip_tunnel_parm p;
1540         struct net *net = t->net;
1541         struct sit_net *sitn = net_generic(net, sit_net_id);
1542 #ifdef CONFIG_IPV6_SIT_6RD
1543         struct ip_tunnel_6rd ip6rd;
1544 #endif
1545
1546         if (dev == sitn->fb_tunnel_dev)
1547                 return -EINVAL;
1548
1549         ipip6_netlink_parms(data, &p);
1550
1551         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1552             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1553                 return -EINVAL;
1554
1555         t = ipip6_tunnel_locate(net, &p, 0);
1556
1557         if (t) {
1558                 if (t->dev != dev)
1559                         return -EEXIST;
1560         } else
1561                 t = netdev_priv(dev);
1562
1563         ipip6_tunnel_update(t, &p);
1564
1565 #ifdef CONFIG_IPV6_SIT_6RD
1566         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1567                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1568 #endif
1569
1570         return 0;
1571 }
1572
1573 static size_t ipip6_get_size(const struct net_device *dev)
1574 {
1575         return
1576                 /* IFLA_IPTUN_LINK */
1577                 nla_total_size(4) +
1578                 /* IFLA_IPTUN_LOCAL */
1579                 nla_total_size(4) +
1580                 /* IFLA_IPTUN_REMOTE */
1581                 nla_total_size(4) +
1582                 /* IFLA_IPTUN_TTL */
1583                 nla_total_size(1) +
1584                 /* IFLA_IPTUN_TOS */
1585                 nla_total_size(1) +
1586                 /* IFLA_IPTUN_PMTUDISC */
1587                 nla_total_size(1) +
1588                 /* IFLA_IPTUN_FLAGS */
1589                 nla_total_size(2) +
1590                 /* IFLA_IPTUN_PROTO */
1591                 nla_total_size(1) +
1592 #ifdef CONFIG_IPV6_SIT_6RD
1593                 /* IFLA_IPTUN_6RD_PREFIX */
1594                 nla_total_size(sizeof(struct in6_addr)) +
1595                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1596                 nla_total_size(4) +
1597                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1598                 nla_total_size(2) +
1599                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1600                 nla_total_size(2) +
1601 #endif
1602                 0;
1603 }
1604
1605 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1606 {
1607         struct ip_tunnel *tunnel = netdev_priv(dev);
1608         struct ip_tunnel_parm *parm = &tunnel->parms;
1609
1610         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1611             nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1612             nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1613             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1614             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1615             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1616                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1617             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1618             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1619                 goto nla_put_failure;
1620
1621 #ifdef CONFIG_IPV6_SIT_6RD
1622         if (nla_put(skb, IFLA_IPTUN_6RD_PREFIX, sizeof(struct in6_addr),
1623                     &tunnel->ip6rd.prefix) ||
1624             nla_put_be32(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1625                          tunnel->ip6rd.relay_prefix) ||
1626             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1627                         tunnel->ip6rd.prefixlen) ||
1628             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1629                         tunnel->ip6rd.relay_prefixlen))
1630                 goto nla_put_failure;
1631 #endif
1632
1633         return 0;
1634
1635 nla_put_failure:
1636         return -EMSGSIZE;
1637 }
1638
1639 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1640         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1641         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1642         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1643         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1644         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1645         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1646         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1647         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1648 #ifdef CONFIG_IPV6_SIT_6RD
1649         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1650         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1651         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1652         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1653 #endif
1654 };
1655
1656 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1657 {
1658         struct net *net = dev_net(dev);
1659         struct sit_net *sitn = net_generic(net, sit_net_id);
1660
1661         if (dev != sitn->fb_tunnel_dev)
1662                 unregister_netdevice_queue(dev, head);
1663 }
1664
1665 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1666         .kind           = "sit",
1667         .maxtype        = IFLA_IPTUN_MAX,
1668         .policy         = ipip6_policy,
1669         .priv_size      = sizeof(struct ip_tunnel),
1670         .setup          = ipip6_tunnel_setup,
1671         .validate       = ipip6_validate,
1672         .newlink        = ipip6_newlink,
1673         .changelink     = ipip6_changelink,
1674         .get_size       = ipip6_get_size,
1675         .fill_info      = ipip6_fill_info,
1676         .dellink        = ipip6_dellink,
1677 };
1678
1679 static struct xfrm_tunnel sit_handler __read_mostly = {
1680         .handler        =       ipip6_rcv,
1681         .err_handler    =       ipip6_err,
1682         .priority       =       1,
1683 };
1684
1685 static struct xfrm_tunnel ipip_handler __read_mostly = {
1686         .handler        =       ipip_rcv,
1687         .err_handler    =       ipip6_err,
1688         .priority       =       2,
1689 };
1690
1691 static void __net_exit sit_destroy_tunnels(struct net *net,
1692                                            struct list_head *head)
1693 {
1694         struct sit_net *sitn = net_generic(net, sit_net_id);
1695         struct net_device *dev, *aux;
1696         int prio;
1697
1698         for_each_netdev_safe(net, dev, aux)
1699                 if (dev->rtnl_link_ops == &sit_link_ops)
1700                         unregister_netdevice_queue(dev, head);
1701
1702         for (prio = 1; prio < 4; prio++) {
1703                 int h;
1704                 for (h = 0; h < HASH_SIZE; h++) {
1705                         struct ip_tunnel *t;
1706
1707                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1708                         while (t != NULL) {
1709                                 /* If dev is in the same netns, it has already
1710                                  * been added to the list by the previous loop.
1711                                  */
1712                                 if (!net_eq(dev_net(t->dev), net))
1713                                         unregister_netdevice_queue(t->dev,
1714                                                                    head);
1715                                 t = rtnl_dereference(t->next);
1716                         }
1717                 }
1718         }
1719 }
1720
1721 static int __net_init sit_init_net(struct net *net)
1722 {
1723         struct sit_net *sitn = net_generic(net, sit_net_id);
1724         struct ip_tunnel *t;
1725         int err;
1726
1727         sitn->tunnels[0] = sitn->tunnels_wc;
1728         sitn->tunnels[1] = sitn->tunnels_l;
1729         sitn->tunnels[2] = sitn->tunnels_r;
1730         sitn->tunnels[3] = sitn->tunnels_r_l;
1731
1732         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1733                                            NET_NAME_UNKNOWN,
1734                                            ipip6_tunnel_setup);
1735         if (!sitn->fb_tunnel_dev) {
1736                 err = -ENOMEM;
1737                 goto err_alloc_dev;
1738         }
1739         dev_net_set(sitn->fb_tunnel_dev, net);
1740         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1741         /* FB netdevice is special: we have one, and only one per netns.
1742          * Allowing to move it to another netns is clearly unsafe.
1743          */
1744         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1745
1746         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1747         if (err)
1748                 goto err_dev_free;
1749
1750         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1751
1752         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1753                 goto err_reg_dev;
1754
1755         t = netdev_priv(sitn->fb_tunnel_dev);
1756
1757         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1758         return 0;
1759
1760 err_reg_dev:
1761         dev_put(sitn->fb_tunnel_dev);
1762 err_dev_free:
1763         ipip6_dev_free(sitn->fb_tunnel_dev);
1764 err_alloc_dev:
1765         return err;
1766 }
1767
1768 static void __net_exit sit_exit_net(struct net *net)
1769 {
1770         LIST_HEAD(list);
1771
1772         rtnl_lock();
1773         sit_destroy_tunnels(net, &list);
1774         unregister_netdevice_many(&list);
1775         rtnl_unlock();
1776 }
1777
1778 static struct pernet_operations sit_net_ops = {
1779         .init = sit_init_net,
1780         .exit = sit_exit_net,
1781         .id   = &sit_net_id,
1782         .size = sizeof(struct sit_net),
1783 };
1784
1785 static void __exit sit_cleanup(void)
1786 {
1787         rtnl_link_unregister(&sit_link_ops);
1788         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1789         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1790
1791         unregister_pernet_device(&sit_net_ops);
1792         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1793 }
1794
1795 static int __init sit_init(void)
1796 {
1797         int err;
1798
1799         pr_info("IPv6 over IPv4 tunneling driver\n");
1800
1801         err = register_pernet_device(&sit_net_ops);
1802         if (err < 0)
1803                 return err;
1804         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1805         if (err < 0) {
1806                 pr_info("%s: can't register ip6ip4\n", __func__);
1807                 goto xfrm_tunnel_failed;
1808         }
1809         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1810         if (err < 0) {
1811                 pr_info("%s: can't register ip4ip4\n", __func__);
1812                 goto xfrm_tunnel4_failed;
1813         }
1814         err = rtnl_link_register(&sit_link_ops);
1815         if (err < 0)
1816                 goto rtnl_link_failed;
1817
1818 out:
1819         return err;
1820
1821 rtnl_link_failed:
1822         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1823 xfrm_tunnel4_failed:
1824         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1825 xfrm_tunnel_failed:
1826         unregister_pernet_device(&sit_net_ops);
1827         goto out;
1828 }
1829
1830 module_init(sit_init);
1831 module_exit(sit_cleanup);
1832 MODULE_LICENSE("GPL");
1833 MODULE_ALIAS_RTNL_LINK("sit");
1834 MODULE_ALIAS_NETDEV("sit0");