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, ipip6_tunnel_setup);
 254         if (dev == NULL)
 255                 return NULL;
 256
 257         dev_net_set(dev, net);
 258
 259         nt = netdev_priv(dev);
 260
 261         nt->parms = *parms;
 262         if (ipip6_tunnel_create(dev) < 0)
 263                 goto failed_free;
 264
 265         return nt;
 266
 267 failed_free:
 268         ipip6_dev_free(dev);
 269 failed:
 270         return NULL;
 271 }
 272
 273 #define for_each_prl_rcu(start)                 \
 274         for (prl = rcu_dereference(start);      \
 275              prl;                               \
 276              prl = rcu_dereference(prl->next))
 277
 278 static struct ip_tunnel_prl_entry *
 279 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 280 {
 281         struct ip_tunnel_prl_entry *prl;
 282
 283         for_each_prl_rcu(t->prl)
 284                 if (prl->addr == addr)
 285                         break;
 286         return prl;
 287
 288 }
 289
 290 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 291                                 struct ip_tunnel_prl __user *a)
 292 {
 293         struct ip_tunnel_prl kprl, *kp;
 294         struct ip_tunnel_prl_entry *prl;
 295         unsigned int cmax, c = 0, ca, len;
 296         int ret = 0;
 297
 298         if (copy_from_user(&kprl, a, sizeof(kprl)))
 299                 return -EFAULT;
 300         cmax = kprl.datalen / sizeof(kprl);
 301         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 302                 cmax = 1;
 303
 304         /* For simple GET or for root users,
 305          * we try harder to allocate.
 306          */
 307         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 308                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 309                 NULL;
 310
 311         rcu_read_lock();
 312
 313         ca = t->prl_count < cmax ? t->prl_count : cmax;
 314
 315         if (!kp) {
 316                 /* We don't try hard to allocate much memory for
 317                  * non-root users.
 318                  * For root users, retry allocating enough memory for
 319                  * the answer.
 320                  */
 321                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 322                 if (!kp) {
 323                         ret = -ENOMEM;
 324                         goto out;
 325                 }
 326         }
 327
 328         c = 0;
 329         for_each_prl_rcu(t->prl) {
 330                 if (c >= cmax)
 331                         break;
 332                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 333                         continue;
 334                 kp[c].addr = prl->addr;
 335                 kp[c].flags = prl->flags;
 336                 c++;
 337                 if (kprl.addr != htonl(INADDR_ANY))
 338                         break;
 339         }
 340 out:
 341         rcu_read_unlock();
 342
 343         len = sizeof(*kp) * c;
 344         ret = 0;
 345         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 346                 ret = -EFAULT;
 347
 348         kfree(kp);
 349
 350         return ret;
 351 }
 352
 353 static int
 354 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 355 {
 356         struct ip_tunnel_prl_entry *p;
 357         int err = 0;
 358
 359         if (a->addr == htonl(INADDR_ANY))
 360                 return -EINVAL;
 361
 362         ASSERT_RTNL();
 363
 364         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 365                 if (p->addr == a->addr) {
 366                         if (chg) {
 367                                 p->flags = a->flags;
 368                                 goto out;
 369                         }
 370                         err = -EEXIST;
 371                         goto out;
 372                 }
 373         }
 374
 375         if (chg) {
 376                 err = -ENXIO;
 377                 goto out;
 378         }
 379
 380         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 381         if (!p) {
 382                 err = -ENOBUFS;
 383                 goto out;
 384         }
 385
 386         p->next = t->prl;
 387         p->addr = a->addr;
 388         p->flags = a->flags;
 389         t->prl_count++;
 390         rcu_assign_pointer(t->prl, p);
 391 out:
 392         return err;
 393 }
 394
 395 static void prl_list_destroy_rcu(struct rcu_head *head)
 396 {
 397         struct ip_tunnel_prl_entry *p, *n;
 398
 399         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 400         do {
 401                 n = rcu_dereference_protected(p->next, 1);
 402                 kfree(p);
 403                 p = n;
 404         } while (p);
 405 }
 406
 407 static int
 408 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 409 {
 410         struct ip_tunnel_prl_entry *x;
 411         struct ip_tunnel_prl_entry __rcu **p;
 412         int err = 0;
 413
 414         ASSERT_RTNL();
 415
 416         if (a && a->addr != htonl(INADDR_ANY)) {
 417                 for (p = &t->prl;
 418                      (x = rtnl_dereference(*p)) != NULL;
 419                      p = &x->next) {
 420                         if (x->addr == a->addr) {
 421                                 *p = x->next;
 422                                 kfree_rcu(x, rcu_head);
 423                                 t->prl_count--;
 424                                 goto out;
 425                         }
 426                 }
 427                 err = -ENXIO;
 428         } else {
 429                 x = rtnl_dereference(t->prl);
 430                 if (x) {
 431                         t->prl_count = 0;
 432                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 433                         t->prl = NULL;
 434                 }
 435         }
 436 out:
 437         return err;
 438 }
 439
 440 static int
 441 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 442 {
 443         struct ip_tunnel_prl_entry *p;
 444         int ok = 1;
 445
 446         rcu_read_lock();
 447         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 448         if (p) {
 449                 if (p->flags & PRL_DEFAULT)
 450                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 451                 else
 452                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 453         } else {
 454                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 455
 456                 if (ipv6_addr_is_isatap(addr6) &&
 457                     (addr6->s6_addr32[3] == iph->saddr) &&
 458                     ipv6_chk_prefix(addr6, t->dev))
 459                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 460                 else
 461                         ok = 0;
 462         }
 463         rcu_read_unlock();
 464         return ok;
 465 }
 466
 467 static void ipip6_tunnel_uninit(struct net_device *dev)
 468 {
 469         struct ip_tunnel *tunnel = netdev_priv(dev);
 470         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 471
 472         if (dev == sitn->fb_tunnel_dev) {
 473                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 474         } else {
 475                 ipip6_tunnel_unlink(sitn, tunnel);
 476                 ipip6_tunnel_del_prl(tunnel, NULL);
 477         }
 478         dev_put(dev);
 479 }
 480
 481 /* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
 482  * if sufficient data bytes are available
 483  */
 484 static int ipip6_err_gen_icmpv6_unreach(struct sk_buff *skb)
 485 {
 486         const struct iphdr *iph = (const struct iphdr *) skb->data;
 487         struct rt6_info *rt;
 488         struct sk_buff *skb2;
 489
 490         if (!pskb_may_pull(skb, iph->ihl * 4 + sizeof(struct ipv6hdr) + 8))
 491                 return 1;
 492
 493         skb2 = skb_clone(skb, GFP_ATOMIC);
 494
 495         if (!skb2)
 496                 return 1;
 497
 498         skb_dst_drop(skb2);
 499         skb_pull(skb2, iph->ihl * 4);
 500         skb_reset_network_header(skb2);
 501
 502         rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);
 503
 504         if (rt && rt->dst.dev)
 505                 skb2->dev = rt->dst.dev;
 506
 507         icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 508
 509         if (rt)
 510                 ip6_rt_put(rt);
 511
 512         kfree_skb(skb2);
 513
 514         return 0;
 515 }
 516
 517 static int ipip6_err(struct sk_buff *skb, u32 info)
 518 {
 519         const struct iphdr *iph = (const struct iphdr *)skb->data;
 520         const int type = icmp_hdr(skb)->type;
 521         const int code = icmp_hdr(skb)->code;
 522         struct ip_tunnel *t;
 523         int err;
 524
 525         switch (type) {
 526         default:
 527         case ICMP_PARAMETERPROB:
 528                 return 0;
 529
 530         case ICMP_DEST_UNREACH:
 531                 switch (code) {
 532                 case ICMP_SR_FAILED:
 533                         /* Impossible event. */
 534                         return 0;
 535                 default:
 536                         /* All others are translated to HOST_UNREACH.
 537                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 538                            I believe they are just ether pollution. --ANK
 539                          */
 540                         break;
 541                 }
 542                 break;
 543         case ICMP_TIME_EXCEEDED:
 544                 if (code != ICMP_EXC_TTL)
 545                         return 0;
 546                 break;
 547         case ICMP_REDIRECT:
 548                 break;
 549         }
 550
 551         err = -ENOENT;
 552
 553         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 554                                 skb->dev,
 555                                 iph->daddr,
 556                                 iph->saddr);
 557         if (t == NULL)
 558                 goto out;
 559
 560         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 561                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 562                                  t->dev->ifindex, 0, IPPROTO_IPV6, 0);
 563                 err = 0;
 564                 goto out;
 565         }
 566         if (type == ICMP_REDIRECT) {
 567                 ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
 568                               IPPROTO_IPV6, 0);
 569                 err = 0;
 570                 goto out;
 571         }
 572
 573         if (t->parms.iph.daddr == 0)
 574                 goto out;
 575
 576         err = 0;
 577         if (!ipip6_err_gen_icmpv6_unreach(skb))
 578                 goto out;
 579
 580         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 581                 goto out;
 582
 583         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 584                 t->err_count++;
 585         else
 586                 t->err_count = 1;
 587         t->err_time = jiffies;
 588 out:
 589         return err;
 590 }
 591
 592 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 593                                   const struct in6_addr *v6addr)
 594 {
 595         __be32 v4embed = 0;
 596         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 597                 return true;
 598         return false;
 599 }
 600
 601 /* Checks if an address matches an address on the tunnel interface.
 602  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 603  * Long story:
 604  * This function is called after we considered the packet as spoofed
 605  * in is_spoofed_6rd.
 606  * We may have a router that is doing NAT for proto 41 packets
 607  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 608  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 609  * function will return true, dropping the packet.
 610  * But, we can still check if is spoofed against the IP
 611  * addresses associated with the interface.
 612  */
 613 static bool only_dnatted(const struct ip_tunnel *tunnel,
 614         const struct in6_addr *v6dst)
 615 {
 616         int prefix_len;
 617
 618 #ifdef CONFIG_IPV6_SIT_6RD
 619         prefix_len = tunnel->ip6rd.prefixlen + 32
 620                 - tunnel->ip6rd.relay_prefixlen;
 621 #else
 622         prefix_len = 48;
 623 #endif
 624         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 625 }
 626
 627 /* Returns true if a packet is spoofed */
 628 static bool packet_is_spoofed(struct sk_buff *skb,
 629                               const struct iphdr *iph,
 630                               struct ip_tunnel *tunnel)
 631 {
 632         const struct ipv6hdr *ipv6h;
 633
 634         if (tunnel->dev->priv_flags & IFF_ISATAP) {
 635                 if (!isatap_chksrc(skb, iph, tunnel))
 636                         return true;
 637
 638                 return false;
 639         }
 640
 641         if (tunnel->dev->flags & IFF_POINTOPOINT)
 642                 return false;
 643
 644         ipv6h = ipv6_hdr(skb);
 645
 646         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 647                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 648                                      &iph->saddr, &ipv6h->saddr,
 649                                      &iph->daddr, &ipv6h->daddr);
 650                 return true;
 651         }
 652
 653         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 654                 return false;
 655
 656         if (only_dnatted(tunnel, &ipv6h->daddr))
 657                 return false;
 658
 659         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 660                              &iph->saddr, &ipv6h->saddr,
 661                              &iph->daddr, &ipv6h->daddr);
 662         return true;
 663 }
 664
 665 static int ipip6_rcv(struct sk_buff *skb)
 666 {
 667         const struct iphdr *iph = ip_hdr(skb);
 668         struct ip_tunnel *tunnel;
 669         int err;
 670
 671         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 672                                      iph->saddr, iph->daddr);
 673         if (tunnel != NULL) {
 674                 struct pcpu_tstats *tstats;
 675
 676                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 677                     tunnel->parms.iph.protocol != 0)
 678                         goto out;
 679
 680                 skb->mac_header = skb->network_header;
 681                 skb_reset_network_header(skb);
 682                 IPCB(skb)->flags = 0;
 683                 skb->protocol = htons(ETH_P_IPV6);
 684
 685                 if (packet_is_spoofed(skb, iph, tunnel)) {
 686                         tunnel->dev->stats.rx_errors++;
 687                         goto out;
 688                 }
 689
 690                 __skb_tunnel_rx(skb, tunnel->dev, tunnel->net);
 691
 692                 err = IP_ECN_decapsulate(iph, skb);
 693                 if (unlikely(err)) {
 694                         if (log_ecn_error)
 695                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 696                                                      &iph->saddr, iph->tos);
 697                         if (err > 1) {
 698                                 ++tunnel->dev->stats.rx_frame_errors;
 699                                 ++tunnel->dev->stats.rx_errors;
 700                                 goto out;
 701                         }
 702                 }
 703
 704                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 705                 tstats->rx_packets++;
 706                 tstats->rx_bytes += skb->len;
 707
 708                 netif_rx(skb);
 709
 710                 return 0;
 711         }
 712
 713         /* no tunnel matched,  let upstream know, ipsec may handle it */
 714         return 1;
 715 out:
 716         kfree_skb(skb);
 717         return 0;
 718 }
 719
 720 static const struct tnl_ptk_info tpi = {
 721         /* no tunnel info required for ipip. */
 722         .proto = htons(ETH_P_IP),
 723 };
 724
 725 static int ipip_rcv(struct sk_buff *skb)
 726 {
 727         const struct iphdr *iph;
 728         struct ip_tunnel *tunnel;
 729
 730         iph = ip_hdr(skb);
 731         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 732                                      iph->saddr, iph->daddr);
 733         if (tunnel != NULL) {
 734                 if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 735                     tunnel->parms.iph.protocol != 0)
 736                         goto drop;
 737
 738                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 739                         goto drop;
 740                 if (iptunnel_pull_header(skb, 0, tpi.proto))
 741                         goto drop;
 742                 return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
 743         }
 744
 745         return 1;
 746
 747 drop:
 748         kfree_skb(skb);
 749         return 0;
 750 }
 751
 752 /*
 753  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 754  * stores the embedded IPv4 address in v4dst and returns true.
 755  */
 756 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 757                       __be32 *v4dst)
 758 {
 759 #ifdef CONFIG_IPV6_SIT_6RD
 760         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 761                               tunnel->ip6rd.prefixlen)) {
 762                 unsigned int pbw0, pbi0;
 763                 int pbi1;
 764                 u32 d;
 765
 766                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 767                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 768
 769                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 770                     tunnel->ip6rd.relay_prefixlen;
 771
 772                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 773                 if (pbi1 > 0)
 774                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 775                              (32 - pbi1);
 776
 777                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 778                 return true;
 779         }
 780 #else
 781         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 782                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 783                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 784                 return true;
 785         }
 786 #endif
 787         return false;
 788 }
 789
 790 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 791                              const struct in6_addr *v6dst)
 792 {
 793         __be32 dst = 0;
 794         check_6rd(tunnel, v6dst, &dst);
 795         return dst;
 796 }
 797
 798 /*
 799  *      This function assumes it is being called from dev_queue_xmit()
 800  *      and that skb is filled properly by that function.
 801  */
 802
 803 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 804                                      struct net_device *dev)
 805 {
 806         struct ip_tunnel *tunnel = netdev_priv(dev);
 807         const struct iphdr  *tiph = &tunnel->parms.iph;
 808         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 809         u8     tos = tunnel->parms.iph.tos;
 810         __be16 df = tiph->frag_off;
 811         struct rtable *rt;                      /* Route to the other host */
 812         struct net_device *tdev;                /* Device to other host */
 813         unsigned int max_headroom;              /* The extra header space needed */
 814         __be32 dst = tiph->daddr;
 815         struct flowi4 fl4;
 816         int    mtu;
 817         const struct in6_addr *addr6;
 818         int addr_type;
 819         u8 ttl;
 820         int err;
 821
 822         if (skb->protocol != htons(ETH_P_IPV6))
 823                 goto tx_error;
 824
 825         if (tos == 1)
 826                 tos = ipv6_get_dsfield(iph6);
 827
 828         /* ISATAP (RFC4214) - must come before 6to4 */
 829         if (dev->priv_flags & IFF_ISATAP) {
 830                 struct neighbour *neigh = NULL;
 831                 bool do_tx_error = false;
 832
 833                 if (skb_dst(skb))
 834                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 835
 836                 if (neigh == NULL) {
 837                         net_dbg_ratelimited("nexthop == NULL\n");
 838                         goto tx_error;
 839                 }
 840
 841                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 842                 addr_type = ipv6_addr_type(addr6);
 843
 844                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 845                      ipv6_addr_is_isatap(addr6))
 846                         dst = addr6->s6_addr32[3];
 847                 else
 848                         do_tx_error = true;
 849
 850                 neigh_release(neigh);
 851                 if (do_tx_error)
 852                         goto tx_error;
 853         }
 854
 855         if (!dst)
 856                 dst = try_6rd(tunnel, &iph6->daddr);
 857
 858         if (!dst) {
 859                 struct neighbour *neigh = NULL;
 860                 bool do_tx_error = false;
 861
 862                 if (skb_dst(skb))
 863                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 864
 865                 if (neigh == NULL) {
 866                         net_dbg_ratelimited("nexthop == NULL\n");
 867                         goto tx_error;
 868                 }
 869
 870                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 871                 addr_type = ipv6_addr_type(addr6);
 872
 873                 if (addr_type == IPV6_ADDR_ANY) {
 874                         addr6 = &ipv6_hdr(skb)->daddr;
 875                         addr_type = ipv6_addr_type(addr6);
 876                 }
 877
 878                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 879                         dst = addr6->s6_addr32[3];
 880                 else
 881                         do_tx_error = true;
 882
 883                 neigh_release(neigh);
 884                 if (do_tx_error)
 885                         goto tx_error;
 886         }
 887
 888         rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 889                                    dst, tiph->saddr,
 890                                    0, 0,
 891                                    IPPROTO_IPV6, RT_TOS(tos),
 892                                    tunnel->parms.link);
 893         if (IS_ERR(rt)) {
 894                 dev->stats.tx_carrier_errors++;
 895                 goto tx_error_icmp;
 896         }
 897         if (rt->rt_type != RTN_UNICAST) {
 898                 ip_rt_put(rt);
 899                 dev->stats.tx_carrier_errors++;
 900                 goto tx_error_icmp;
 901         }
 902         tdev = rt->dst.dev;
 903
 904         if (tdev == dev) {
 905                 ip_rt_put(rt);
 906                 dev->stats.collisions++;
 907                 goto tx_error;
 908         }
 909
 910         if (df) {
 911                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 912
 913                 if (mtu < 68) {
 914                         dev->stats.collisions++;
 915                         ip_rt_put(rt);
 916                         goto tx_error;
 917                 }
 918
 919                 if (mtu < IPV6_MIN_MTU) {
 920                         mtu = IPV6_MIN_MTU;
 921                         df = 0;
 922                 }
 923
 924                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 925                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 926
 927                 if (skb->len > mtu) {
 928                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 929                         ip_rt_put(rt);
 930                         goto tx_error;
 931                 }
 932         }
 933
 934         if (tunnel->err_count > 0) {
 935                 if (time_before(jiffies,
 936                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 937                         tunnel->err_count--;
 938                         dst_link_failure(skb);
 939                 } else
 940                         tunnel->err_count = 0;
 941         }
 942
 943         /*
 944          * Okay, now see if we can stuff it in the buffer as-is.
 945          */
 946         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 947
 948         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 949             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 950                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 951                 if (!new_skb) {
 952                         ip_rt_put(rt);
 953                         dev->stats.tx_dropped++;
 954                         kfree_skb(skb);
 955                         return NETDEV_TX_OK;
 956                 }
 957                 if (skb->sk)
 958                         skb_set_owner_w(new_skb, skb->sk);
 959                 dev_kfree_skb(skb);
 960                 skb = new_skb;
 961                 iph6 = ipv6_hdr(skb);
 962         }
 963         ttl = tiph->ttl;
 964         if (ttl == 0)
 965                 ttl = iph6->hop_limit;
 966         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 967
 968         skb = iptunnel_handle_offloads(skb, false, SKB_GSO_SIT);
 969         if (IS_ERR(skb))
 970                 goto out;
 971
 972         err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, IPPROTO_IPV6, tos,
 973                             ttl, df, !net_eq(tunnel->net, dev_net(dev)));
 974         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 975         return NETDEV_TX_OK;
 976
 977 tx_error_icmp:
 978         dst_link_failure(skb);
 979 tx_error:
 980         kfree_skb(skb);
 981 out:
 982         dev->stats.tx_errors++;
 983         return NETDEV_TX_OK;
 984 }
 985
 986 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 987 {
 988         struct ip_tunnel *tunnel = netdev_priv(dev);
 989         const struct iphdr  *tiph = &tunnel->parms.iph;
 990
 991         skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP);
 992         if (IS_ERR(skb))
 993                 goto out;
 994
 995         ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
 996         return NETDEV_TX_OK;
 997 out:
 998         dev->stats.tx_errors++;
 999         return NETDEV_TX_OK;
1000 }
1001
1002 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1003                                    struct net_device *dev)
1004 {
1005         switch (skb->protocol) {
1006         case htons(ETH_P_IP):
1007                 ipip_tunnel_xmit(skb, dev);
1008                 break;
1009         case htons(ETH_P_IPV6):
1010                 ipip6_tunnel_xmit(skb, dev);
1011                 break;
1012         default:
1013                 goto tx_err;
1014         }
1015
1016         return NETDEV_TX_OK;
1017
1018 tx_err:
1019         dev->stats.tx_errors++;
1020         kfree_skb(skb);
1021         return NETDEV_TX_OK;
1022
1023 }
1024
1025 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1026 {
1027         struct net_device *tdev = NULL;
1028         struct ip_tunnel *tunnel;
1029         const struct iphdr *iph;
1030         struct flowi4 fl4;
1031
1032         tunnel = netdev_priv(dev);
1033         iph = &tunnel->parms.iph;
1034
1035         if (iph->daddr) {
1036                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1037                                                           NULL,
1038                                                           iph->daddr, iph->saddr,
1039                                                           0, 0,
1040                                                           IPPROTO_IPV6,
1041                                                           RT_TOS(iph->tos),
1042                                                           tunnel->parms.link);
1043
1044                 if (!IS_ERR(rt)) {
1045                         tdev = rt->dst.dev;
1046                         ip_rt_put(rt);
1047                 }
1048                 dev->flags |= IFF_POINTOPOINT;
1049         }
1050
1051         if (!tdev && tunnel->parms.link)
1052                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1053
1054         if (tdev) {
1055                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1056                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
1057                 if (dev->mtu < IPV6_MIN_MTU)
1058                         dev->mtu = IPV6_MIN_MTU;
1059         }
1060         dev->iflink = tunnel->parms.link;
1061 }
1062
1063 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1064 {
1065         struct net *net = t->net;
1066         struct sit_net *sitn = net_generic(net, sit_net_id);
1067
1068         ipip6_tunnel_unlink(sitn, t);
1069         synchronize_net();
1070         t->parms.iph.saddr = p->iph.saddr;
1071         t->parms.iph.daddr = p->iph.daddr;
1072         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1073         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1074         ipip6_tunnel_link(sitn, t);
1075         t->parms.iph.ttl = p->iph.ttl;
1076         t->parms.iph.tos = p->iph.tos;
1077         if (t->parms.link != p->link) {
1078                 t->parms.link = p->link;
1079                 ipip6_tunnel_bind_dev(t->dev);
1080         }
1081         netdev_state_change(t->dev);
1082 }
1083
1084 #ifdef CONFIG_IPV6_SIT_6RD
1085 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1086                                    struct ip_tunnel_6rd *ip6rd)
1087 {
1088         struct in6_addr prefix;
1089         __be32 relay_prefix;
1090
1091         if (ip6rd->relay_prefixlen > 32 ||
1092             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1093                 return -EINVAL;
1094
1095         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1096         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1097                 return -EINVAL;
1098         if (ip6rd->relay_prefixlen)
1099                 relay_prefix = ip6rd->relay_prefix &
1100                                htonl(0xffffffffUL <<
1101                                      (32 - ip6rd->relay_prefixlen));
1102         else
1103                 relay_prefix = 0;
1104         if (relay_prefix != ip6rd->relay_prefix)
1105                 return -EINVAL;
1106
1107         t->ip6rd.prefix = prefix;
1108         t->ip6rd.relay_prefix = relay_prefix;
1109         t->ip6rd.prefixlen = ip6rd->prefixlen;
1110         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1111         netdev_state_change(t->dev);
1112         return 0;
1113 }
1114 #endif
1115
1116 static int
1117 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1118 {
1119         int err = 0;
1120         struct ip_tunnel_parm p;
1121         struct ip_tunnel_prl prl;
1122         struct ip_tunnel *t;
1123         struct net *net = dev_net(dev);
1124         struct sit_net *sitn = net_generic(net, sit_net_id);
1125 #ifdef CONFIG_IPV6_SIT_6RD
1126         struct ip_tunnel_6rd ip6rd;
1127 #endif
1128
1129         switch (cmd) {
1130         case SIOCGETTUNNEL:
1131 #ifdef CONFIG_IPV6_SIT_6RD
1132         case SIOCGET6RD:
1133 #endif
1134                 t = NULL;
1135                 if (dev == sitn->fb_tunnel_dev) {
1136                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1137                                 err = -EFAULT;
1138                                 break;
1139                         }
1140                         t = ipip6_tunnel_locate(net, &p, 0);
1141                 }
1142                 if (t == NULL)
1143                         t = netdev_priv(dev);
1144
1145                 err = -EFAULT;
1146                 if (cmd == SIOCGETTUNNEL) {
1147                         memcpy(&p, &t->parms, sizeof(p));
1148                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1149                                          sizeof(p)))
1150                                 goto done;
1151 #ifdef CONFIG_IPV6_SIT_6RD
1152                 } else {
1153                         ip6rd.prefix = t->ip6rd.prefix;
1154                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1155                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1156                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1157                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1158                                          sizeof(ip6rd)))
1159                                 goto done;
1160 #endif
1161                 }
1162                 err = 0;
1163                 break;
1164
1165         case SIOCADDTUNNEL:
1166         case SIOCCHGTUNNEL:
1167                 err = -EPERM;
1168                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1169                         goto done;
1170
1171                 err = -EFAULT;
1172                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1173                         goto done;
1174
1175                 err = -EINVAL;
1176                 if (p.iph.protocol != IPPROTO_IPV6 &&
1177                     p.iph.protocol != IPPROTO_IPIP &&
1178                     p.iph.protocol != 0)
1179                         goto done;
1180                 if (p.iph.version != 4 ||
1181                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1182                         goto done;
1183                 if (p.iph.ttl)
1184                         p.iph.frag_off |= htons(IP_DF);
1185
1186                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1187
1188                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1189                         if (t != NULL) {
1190                                 if (t->dev != dev) {
1191                                         err = -EEXIST;
1192                                         break;
1193                                 }
1194                         } else {
1195                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1196                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1197                                         err = -EINVAL;
1198                                         break;
1199                                 }
1200                                 t = netdev_priv(dev);
1201                         }
1202
1203                         ipip6_tunnel_update(t, &p);
1204                 }
1205
1206                 if (t) {
1207                         err = 0;
1208                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1209                                 err = -EFAULT;
1210                 } else
1211                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1212                 break;
1213
1214         case SIOCDELTUNNEL:
1215                 err = -EPERM;
1216                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1217                         goto done;
1218
1219                 if (dev == sitn->fb_tunnel_dev) {
1220                         err = -EFAULT;
1221                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1222                                 goto done;
1223                         err = -ENOENT;
1224                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1225                                 goto done;
1226                         err = -EPERM;
1227                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1228                                 goto done;
1229                         dev = t->dev;
1230                 }
1231                 unregister_netdevice(dev);
1232                 err = 0;
1233                 break;
1234
1235         case SIOCGETPRL:
1236                 err = -EINVAL;
1237                 if (dev == sitn->fb_tunnel_dev)
1238                         goto done;
1239                 err = -ENOENT;
1240                 if (!(t = netdev_priv(dev)))
1241                         goto done;
1242                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1243                 break;
1244
1245         case SIOCADDPRL:
1246         case SIOCDELPRL:
1247         case SIOCCHGPRL:
1248                 err = -EPERM;
1249                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1250                         goto done;
1251                 err = -EINVAL;
1252                 if (dev == sitn->fb_tunnel_dev)
1253                         goto done;
1254                 err = -EFAULT;
1255                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1256                         goto done;
1257                 err = -ENOENT;
1258                 if (!(t = netdev_priv(dev)))
1259                         goto done;
1260
1261                 switch (cmd) {
1262                 case SIOCDELPRL:
1263                         err = ipip6_tunnel_del_prl(t, &prl);
1264                         break;
1265                 case SIOCADDPRL:
1266                 case SIOCCHGPRL:
1267                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1268                         break;
1269                 }
1270                 netdev_state_change(dev);
1271                 break;
1272
1273 #ifdef CONFIG_IPV6_SIT_6RD
1274         case SIOCADD6RD:
1275         case SIOCCHG6RD:
1276         case SIOCDEL6RD:
1277                 err = -EPERM;
1278                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1279                         goto done;
1280
1281                 err = -EFAULT;
1282                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1283                                    sizeof(ip6rd)))
1284                         goto done;
1285
1286                 t = netdev_priv(dev);
1287
1288                 if (cmd != SIOCDEL6RD) {
1289                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1290                         if (err < 0)
1291                                 goto done;
1292                 } else
1293                         ipip6_tunnel_clone_6rd(dev, sitn);
1294
1295                 err = 0;
1296                 break;
1297 #endif
1298
1299         default:
1300                 err = -EINVAL;
1301         }
1302
1303 done:
1304         return err;
1305 }
1306
1307 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1308 {
1309         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1310                 return -EINVAL;
1311         dev->mtu = new_mtu;
1312         return 0;
1313 }
1314
1315 static const struct net_device_ops ipip6_netdev_ops = {
1316         .ndo_uninit     = ipip6_tunnel_uninit,
1317         .ndo_start_xmit = sit_tunnel_xmit,
1318         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1319         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1320         .ndo_get_stats64 = ip_tunnel_get_stats64,
1321 };
1322
1323 static void ipip6_dev_free(struct net_device *dev)
1324 {
1325         free_percpu(dev->tstats);
1326         free_netdev(dev);
1327 }
1328
1329 #define SIT_FEATURES (NETIF_F_SG           | \
1330                       NETIF_F_FRAGLIST     | \
1331                       NETIF_F_HIGHDMA      | \
1332                       NETIF_F_GSO_SOFTWARE | \
1333                       NETIF_F_HW_CSUM)
1334
1335 static void ipip6_tunnel_setup(struct net_device *dev)
1336 {
1337         dev->netdev_ops         = &ipip6_netdev_ops;
1338         dev->destructor         = ipip6_dev_free;
1339
1340         dev->type               = ARPHRD_SIT;
1341         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1342         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1343         dev->flags              = IFF_NOARP;
1344         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1345         dev->iflink             = 0;
1346         dev->addr_len           = 4;
1347         dev->features           |= NETIF_F_LLTX;
1348         dev->features           |= SIT_FEATURES;
1349         dev->hw_features        |= SIT_FEATURES;
1350 }
1351
1352 static int ipip6_tunnel_init(struct net_device *dev)
1353 {
1354         struct ip_tunnel *tunnel = netdev_priv(dev);
1355         int i;
1356
1357         tunnel->dev = dev;
1358         tunnel->net = dev_net(dev);
1359
1360         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1361         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1362
1363         ipip6_tunnel_bind_dev(dev);
1364         dev->tstats = alloc_percpu(struct pcpu_tstats);
1365         if (!dev->tstats)
1366                 return -ENOMEM;
1367
1368         for_each_possible_cpu(i) {
1369                 struct pcpu_tstats *ipip6_tunnel_stats;
1370                 ipip6_tunnel_stats = per_cpu_ptr(dev->tstats, i);
1371                 u64_stats_init(&ipip6_tunnel_stats->syncp);
1372         }
1373
1374         return 0;
1375 }
1376
1377 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1378 {
1379         struct ip_tunnel *tunnel = netdev_priv(dev);
1380         struct iphdr *iph = &tunnel->parms.iph;
1381         struct net *net = dev_net(dev);
1382         struct sit_net *sitn = net_generic(net, sit_net_id);
1383         int i;
1384
1385         tunnel->dev = dev;
1386         tunnel->net = dev_net(dev);
1387         strcpy(tunnel->parms.name, dev->name);
1388
1389         iph->version            = 4;
1390         iph->protocol           = IPPROTO_IPV6;
1391         iph->ihl                = 5;
1392         iph->ttl                = 64;
1393
1394         dev->tstats = alloc_percpu(struct pcpu_tstats);
1395         if (!dev->tstats)
1396                 return -ENOMEM;
1397
1398         for_each_possible_cpu(i) {
1399                 struct pcpu_tstats *ipip6_fb_stats;
1400                 ipip6_fb_stats = per_cpu_ptr(dev->tstats, i);
1401                 u64_stats_init(&ipip6_fb_stats->syncp);
1402         }
1403
1404         dev_hold(dev);
1405         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1406         return 0;
1407 }
1408
1409 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1410 {
1411         u8 proto;
1412
1413         if (!data || !data[IFLA_IPTUN_PROTO])
1414                 return 0;
1415
1416         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1417         if (proto != IPPROTO_IPV6 &&
1418             proto != IPPROTO_IPIP &&
1419             proto != 0)
1420                 return -EINVAL;
1421
1422         return 0;
1423 }
1424
1425 static void ipip6_netlink_parms(struct nlattr *data[],
1426                                 struct ip_tunnel_parm *parms)
1427 {
1428         memset(parms, 0, sizeof(*parms));
1429
1430         parms->iph.version = 4;
1431         parms->iph.protocol = IPPROTO_IPV6;
1432         parms->iph.ihl = 5;
1433         parms->iph.ttl = 64;
1434
1435         if (!data)
1436                 return;
1437
1438         if (data[IFLA_IPTUN_LINK])
1439                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1440
1441         if (data[IFLA_IPTUN_LOCAL])
1442                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1443
1444         if (data[IFLA_IPTUN_REMOTE])
1445                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1446
1447         if (data[IFLA_IPTUN_TTL]) {
1448                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1449                 if (parms->iph.ttl)
1450                         parms->iph.frag_off = htons(IP_DF);
1451         }
1452
1453         if (data[IFLA_IPTUN_TOS])
1454                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1455
1456         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1457                 parms->iph.frag_off = htons(IP_DF);
1458
1459         if (data[IFLA_IPTUN_FLAGS])
1460                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1461
1462         if (data[IFLA_IPTUN_PROTO])
1463                 parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1464
1465 }
1466
1467 #ifdef CONFIG_IPV6_SIT_6RD
1468 /* This function returns true when 6RD attributes are present in the nl msg */
1469 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1470                                     struct ip_tunnel_6rd *ip6rd)
1471 {
1472         bool ret = false;
1473         memset(ip6rd, 0, sizeof(*ip6rd));
1474
1475         if (!data)
1476                 return ret;
1477
1478         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1479                 ret = true;
1480                 nla_memcpy(&ip6rd->prefix, data[IFLA_IPTUN_6RD_PREFIX],
1481                            sizeof(struct in6_addr));
1482         }
1483
1484         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1485                 ret = true;
1486                 ip6rd->relay_prefix =
1487                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1488         }
1489
1490         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1491                 ret = true;
1492                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1493         }
1494
1495         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1496                 ret = true;
1497                 ip6rd->relay_prefixlen =
1498                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1499         }
1500
1501         return ret;
1502 }
1503 #endif
1504
1505 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1506                          struct nlattr *tb[], struct nlattr *data[])
1507 {
1508         struct net *net = dev_net(dev);
1509         struct ip_tunnel *nt;
1510 #ifdef CONFIG_IPV6_SIT_6RD
1511         struct ip_tunnel_6rd ip6rd;
1512 #endif
1513         int err;
1514
1515         nt = netdev_priv(dev);
1516         ipip6_netlink_parms(data, &nt->parms);
1517
1518         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1519                 return -EEXIST;
1520
1521         err = ipip6_tunnel_create(dev);
1522         if (err < 0)
1523                 return err;
1524
1525 #ifdef CONFIG_IPV6_SIT_6RD
1526         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1527                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1528 #endif
1529
1530         return err;
1531 }
1532
1533 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1534                           struct nlattr *data[])
1535 {
1536         struct ip_tunnel *t = netdev_priv(dev);
1537         struct ip_tunnel_parm p;
1538         struct net *net = t->net;
1539         struct sit_net *sitn = net_generic(net, sit_net_id);
1540 #ifdef CONFIG_IPV6_SIT_6RD
1541         struct ip_tunnel_6rd ip6rd;
1542 #endif
1543
1544         if (dev == sitn->fb_tunnel_dev)
1545                 return -EINVAL;
1546
1547         ipip6_netlink_parms(data, &p);
1548
1549         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1550             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1551                 return -EINVAL;
1552
1553         t = ipip6_tunnel_locate(net, &p, 0);
1554
1555         if (t) {
1556                 if (t->dev != dev)
1557                         return -EEXIST;
1558         } else
1559                 t = netdev_priv(dev);
1560
1561         ipip6_tunnel_update(t, &p);
1562
1563 #ifdef CONFIG_IPV6_SIT_6RD
1564         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1565                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1566 #endif
1567
1568         return 0;
1569 }
1570
1571 static size_t ipip6_get_size(const struct net_device *dev)
1572 {
1573         return
1574                 /* IFLA_IPTUN_LINK */
1575                 nla_total_size(4) +
1576                 /* IFLA_IPTUN_LOCAL */
1577                 nla_total_size(4) +
1578                 /* IFLA_IPTUN_REMOTE */
1579                 nla_total_size(4) +
1580                 /* IFLA_IPTUN_TTL */
1581                 nla_total_size(1) +
1582                 /* IFLA_IPTUN_TOS */
1583                 nla_total_size(1) +
1584                 /* IFLA_IPTUN_PMTUDISC */
1585                 nla_total_size(1) +
1586                 /* IFLA_IPTUN_FLAGS */
1587                 nla_total_size(2) +
1588                 /* IFLA_IPTUN_PROTO */
1589                 nla_total_size(1) +
1590 #ifdef CONFIG_IPV6_SIT_6RD
1591                 /* IFLA_IPTUN_6RD_PREFIX */
1592                 nla_total_size(sizeof(struct in6_addr)) +
1593                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1594                 nla_total_size(4) +
1595                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1596                 nla_total_size(2) +
1597                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1598                 nla_total_size(2) +
1599 #endif
1600                 0;
1601 }
1602
1603 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1604 {
1605         struct ip_tunnel *tunnel = netdev_priv(dev);
1606         struct ip_tunnel_parm *parm = &tunnel->parms;
1607
1608         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1609             nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1610             nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1611             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1612             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1613             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1614                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1615             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1616             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1617                 goto nla_put_failure;
1618
1619 #ifdef CONFIG_IPV6_SIT_6RD
1620         if (nla_put(skb, IFLA_IPTUN_6RD_PREFIX, sizeof(struct in6_addr),
1621                     &tunnel->ip6rd.prefix) ||
1622             nla_put_be32(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1623                          tunnel->ip6rd.relay_prefix) ||
1624             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1625                         tunnel->ip6rd.prefixlen) ||
1626             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1627                         tunnel->ip6rd.relay_prefixlen))
1628                 goto nla_put_failure;
1629 #endif
1630
1631         return 0;
1632
1633 nla_put_failure:
1634         return -EMSGSIZE;
1635 }
1636
1637 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1638         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1639         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1640         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1641         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1642         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1643         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1644         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1645         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1646 #ifdef CONFIG_IPV6_SIT_6RD
1647         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1648         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1649         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1650         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1651 #endif
1652 };
1653
1654 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1655 {
1656         struct net *net = dev_net(dev);
1657         struct sit_net *sitn = net_generic(net, sit_net_id);
1658
1659         if (dev != sitn->fb_tunnel_dev)
1660                 unregister_netdevice_queue(dev, head);
1661 }
1662
1663 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1664         .kind           = "sit",
1665         .maxtype        = IFLA_IPTUN_MAX,
1666         .policy         = ipip6_policy,
1667         .priv_size      = sizeof(struct ip_tunnel),
1668         .setup          = ipip6_tunnel_setup,
1669         .validate       = ipip6_validate,
1670         .newlink        = ipip6_newlink,
1671         .changelink     = ipip6_changelink,
1672         .get_size       = ipip6_get_size,
1673         .fill_info      = ipip6_fill_info,
1674         .dellink        = ipip6_dellink,
1675 };
1676
1677 static struct xfrm_tunnel sit_handler __read_mostly = {
1678         .handler        =       ipip6_rcv,
1679         .err_handler    =       ipip6_err,
1680         .priority       =       1,
1681 };
1682
1683 static struct xfrm_tunnel ipip_handler __read_mostly = {
1684         .handler        =       ipip_rcv,
1685         .err_handler    =       ipip6_err,
1686         .priority       =       2,
1687 };
1688
1689 static void __net_exit sit_destroy_tunnels(struct net *net,
1690                                            struct list_head *head)
1691 {
1692         struct sit_net *sitn = net_generic(net, sit_net_id);
1693         struct net_device *dev, *aux;
1694         int prio;
1695
1696         for_each_netdev_safe(net, dev, aux)
1697                 if (dev->rtnl_link_ops == &sit_link_ops)
1698                         unregister_netdevice_queue(dev, head);
1699
1700         for (prio = 1; prio < 4; prio++) {
1701                 int h;
1702                 for (h = 0; h < HASH_SIZE; h++) {
1703                         struct ip_tunnel *t;
1704
1705                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1706                         while (t != NULL) {
1707                                 /* If dev is in the same netns, it has already
1708                                  * been added to the list by the previous loop.
1709                                  */
1710                                 if (!net_eq(dev_net(t->dev), net))
1711                                         unregister_netdevice_queue(t->dev,
1712                                                                    head);
1713                                 t = rtnl_dereference(t->next);
1714                         }
1715                 }
1716         }
1717 }
1718
1719 static int __net_init sit_init_net(struct net *net)
1720 {
1721         struct sit_net *sitn = net_generic(net, sit_net_id);
1722         struct ip_tunnel *t;
1723         int err;
1724
1725         sitn->tunnels[0] = sitn->tunnels_wc;
1726         sitn->tunnels[1] = sitn->tunnels_l;
1727         sitn->tunnels[2] = sitn->tunnels_r;
1728         sitn->tunnels[3] = sitn->tunnels_r_l;
1729
1730         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1731                                            ipip6_tunnel_setup);
1732         if (!sitn->fb_tunnel_dev) {
1733                 err = -ENOMEM;
1734                 goto err_alloc_dev;
1735         }
1736         dev_net_set(sitn->fb_tunnel_dev, net);
1737         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1738         /* FB netdevice is special: we have one, and only one per netns.
1739          * Allowing to move it to another netns is clearly unsafe.
1740          */
1741         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1742
1743         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1744         if (err)
1745                 goto err_dev_free;
1746
1747         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1748
1749         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1750                 goto err_reg_dev;
1751
1752         t = netdev_priv(sitn->fb_tunnel_dev);
1753
1754         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1755         return 0;
1756
1757 err_reg_dev:
1758         dev_put(sitn->fb_tunnel_dev);
1759 err_dev_free:
1760         ipip6_dev_free(sitn->fb_tunnel_dev);
1761 err_alloc_dev:
1762         return err;
1763 }
1764
1765 static void __net_exit sit_exit_net(struct net *net)
1766 {
1767         LIST_HEAD(list);
1768
1769         rtnl_lock();
1770         sit_destroy_tunnels(net, &list);
1771         unregister_netdevice_many(&list);
1772         rtnl_unlock();
1773 }
1774
1775 static struct pernet_operations sit_net_ops = {
1776         .init = sit_init_net,
1777         .exit = sit_exit_net,
1778         .id   = &sit_net_id,
1779         .size = sizeof(struct sit_net),
1780 };
1781
1782 static void __exit sit_cleanup(void)
1783 {
1784         rtnl_link_unregister(&sit_link_ops);
1785         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1786         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1787
1788         unregister_pernet_device(&sit_net_ops);
1789         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1790 }
1791
1792 static int __init sit_init(void)
1793 {
1794         int err;
1795
1796         pr_info("IPv6 over IPv4 tunneling driver\n");
1797
1798         err = register_pernet_device(&sit_net_ops);
1799         if (err < 0)
1800                 return err;
1801         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1802         if (err < 0) {
1803                 pr_info("%s: can't register ip6ip4\n", __func__);
1804                 goto xfrm_tunnel_failed;
1805         }
1806         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1807         if (err < 0) {
1808                 pr_info("%s: can't register ip4ip4\n", __func__);
1809                 goto xfrm_tunnel4_failed;
1810         }
1811         err = rtnl_link_register(&sit_link_ops);
1812         if (err < 0)
1813                 goto rtnl_link_failed;
1814
1815 out:
1816         return err;
1817
1818 rtnl_link_failed:
1819         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1820 xfrm_tunnel4_failed:
1821         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1822 xfrm_tunnel_failed:
1823         unregister_pernet_device(&sit_net_ops);
1824         goto out;
1825 }
1826
1827 module_init(sit_init);
1828 module_exit(sit_cleanup);
1829 MODULE_LICENSE("GPL");
1830 MODULE_ALIAS_NETDEV("sit0");