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 && !skb_is_gso(skb)) {
 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                 ip_rt_put(rt);
 971                 goto out;
 972         }
 973
 974         err = iptunnel_xmit(rt, skb, fl4.saddr, fl4.daddr, IPPROTO_IPV6, tos,
 975                             ttl, df, !net_eq(tunnel->net, dev_net(dev)));
 976         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 977         return NETDEV_TX_OK;
 978
 979 tx_error_icmp:
 980         dst_link_failure(skb);
 981 tx_error:
 982         kfree_skb(skb);
 983 out:
 984         dev->stats.tx_errors++;
 985         return NETDEV_TX_OK;
 986 }
 987
 988 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 989 {
 990         struct ip_tunnel *tunnel = netdev_priv(dev);
 991         const struct iphdr  *tiph = &tunnel->parms.iph;
 992
 993         skb = iptunnel_handle_offloads(skb, false, SKB_GSO_IPIP);
 994         if (IS_ERR(skb))
 995                 goto out;
 996
 997         ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
 998         return NETDEV_TX_OK;
 999 out:
1000         dev->stats.tx_errors++;
1001         return NETDEV_TX_OK;
1002 }
1003
1004 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1005                                    struct net_device *dev)
1006 {
1007         switch (skb->protocol) {
1008         case htons(ETH_P_IP):
1009                 ipip_tunnel_xmit(skb, dev);
1010                 break;
1011         case htons(ETH_P_IPV6):
1012                 ipip6_tunnel_xmit(skb, dev);
1013                 break;
1014         default:
1015                 goto tx_err;
1016         }
1017
1018         return NETDEV_TX_OK;
1019
1020 tx_err:
1021         dev->stats.tx_errors++;
1022         kfree_skb(skb);
1023         return NETDEV_TX_OK;
1024
1025 }
1026
1027 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1028 {
1029         struct net_device *tdev = NULL;
1030         struct ip_tunnel *tunnel;
1031         const struct iphdr *iph;
1032         struct flowi4 fl4;
1033
1034         tunnel = netdev_priv(dev);
1035         iph = &tunnel->parms.iph;
1036
1037         if (iph->daddr) {
1038                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1039                                                           NULL,
1040                                                           iph->daddr, iph->saddr,
1041                                                           0, 0,
1042                                                           IPPROTO_IPV6,
1043                                                           RT_TOS(iph->tos),
1044                                                           tunnel->parms.link);
1045
1046                 if (!IS_ERR(rt)) {
1047                         tdev = rt->dst.dev;
1048                         ip_rt_put(rt);
1049                 }
1050                 dev->flags |= IFF_POINTOPOINT;
1051         }
1052
1053         if (!tdev && tunnel->parms.link)
1054                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1055
1056         if (tdev) {
1057                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1058                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
1059                 if (dev->mtu < IPV6_MIN_MTU)
1060                         dev->mtu = IPV6_MIN_MTU;
1061         }
1062         dev->iflink = tunnel->parms.link;
1063 }
1064
1065 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1066 {
1067         struct net *net = t->net;
1068         struct sit_net *sitn = net_generic(net, sit_net_id);
1069
1070         ipip6_tunnel_unlink(sitn, t);
1071         synchronize_net();
1072         t->parms.iph.saddr = p->iph.saddr;
1073         t->parms.iph.daddr = p->iph.daddr;
1074         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1075         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1076         ipip6_tunnel_link(sitn, t);
1077         t->parms.iph.ttl = p->iph.ttl;
1078         t->parms.iph.tos = p->iph.tos;
1079         if (t->parms.link != p->link) {
1080                 t->parms.link = p->link;
1081                 ipip6_tunnel_bind_dev(t->dev);
1082         }
1083         netdev_state_change(t->dev);
1084 }
1085
1086 #ifdef CONFIG_IPV6_SIT_6RD
1087 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1088                                    struct ip_tunnel_6rd *ip6rd)
1089 {
1090         struct in6_addr prefix;
1091         __be32 relay_prefix;
1092
1093         if (ip6rd->relay_prefixlen > 32 ||
1094             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1095                 return -EINVAL;
1096
1097         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1098         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1099                 return -EINVAL;
1100         if (ip6rd->relay_prefixlen)
1101                 relay_prefix = ip6rd->relay_prefix &
1102                                htonl(0xffffffffUL <<
1103                                      (32 - ip6rd->relay_prefixlen));
1104         else
1105                 relay_prefix = 0;
1106         if (relay_prefix != ip6rd->relay_prefix)
1107                 return -EINVAL;
1108
1109         t->ip6rd.prefix = prefix;
1110         t->ip6rd.relay_prefix = relay_prefix;
1111         t->ip6rd.prefixlen = ip6rd->prefixlen;
1112         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1113         netdev_state_change(t->dev);
1114         return 0;
1115 }
1116 #endif
1117
1118 static int
1119 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1120 {
1121         int err = 0;
1122         struct ip_tunnel_parm p;
1123         struct ip_tunnel_prl prl;
1124         struct ip_tunnel *t;
1125         struct net *net = dev_net(dev);
1126         struct sit_net *sitn = net_generic(net, sit_net_id);
1127 #ifdef CONFIG_IPV6_SIT_6RD
1128         struct ip_tunnel_6rd ip6rd;
1129 #endif
1130
1131         switch (cmd) {
1132         case SIOCGETTUNNEL:
1133 #ifdef CONFIG_IPV6_SIT_6RD
1134         case SIOCGET6RD:
1135 #endif
1136                 t = NULL;
1137                 if (dev == sitn->fb_tunnel_dev) {
1138                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1139                                 err = -EFAULT;
1140                                 break;
1141                         }
1142                         t = ipip6_tunnel_locate(net, &p, 0);
1143                 }
1144                 if (t == NULL)
1145                         t = netdev_priv(dev);
1146
1147                 err = -EFAULT;
1148                 if (cmd == SIOCGETTUNNEL) {
1149                         memcpy(&p, &t->parms, sizeof(p));
1150                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1151                                          sizeof(p)))
1152                                 goto done;
1153 #ifdef CONFIG_IPV6_SIT_6RD
1154                 } else {
1155                         ip6rd.prefix = t->ip6rd.prefix;
1156                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1157                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1158                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1159                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1160                                          sizeof(ip6rd)))
1161                                 goto done;
1162 #endif
1163                 }
1164                 err = 0;
1165                 break;
1166
1167         case SIOCADDTUNNEL:
1168         case SIOCCHGTUNNEL:
1169                 err = -EPERM;
1170                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1171                         goto done;
1172
1173                 err = -EFAULT;
1174                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1175                         goto done;
1176
1177                 err = -EINVAL;
1178                 if (p.iph.protocol != IPPROTO_IPV6 &&
1179                     p.iph.protocol != IPPROTO_IPIP &&
1180                     p.iph.protocol != 0)
1181                         goto done;
1182                 if (p.iph.version != 4 ||
1183                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1184                         goto done;
1185                 if (p.iph.ttl)
1186                         p.iph.frag_off |= htons(IP_DF);
1187
1188                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1189
1190                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1191                         if (t != NULL) {
1192                                 if (t->dev != dev) {
1193                                         err = -EEXIST;
1194                                         break;
1195                                 }
1196                         } else {
1197                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1198                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1199                                         err = -EINVAL;
1200                                         break;
1201                                 }
1202                                 t = netdev_priv(dev);
1203                         }
1204
1205                         ipip6_tunnel_update(t, &p);
1206                 }
1207
1208                 if (t) {
1209                         err = 0;
1210                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1211                                 err = -EFAULT;
1212                 } else
1213                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1214                 break;
1215
1216         case SIOCDELTUNNEL:
1217                 err = -EPERM;
1218                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1219                         goto done;
1220
1221                 if (dev == sitn->fb_tunnel_dev) {
1222                         err = -EFAULT;
1223                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1224                                 goto done;
1225                         err = -ENOENT;
1226                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1227                                 goto done;
1228                         err = -EPERM;
1229                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1230                                 goto done;
1231                         dev = t->dev;
1232                 }
1233                 unregister_netdevice(dev);
1234                 err = 0;
1235                 break;
1236
1237         case SIOCGETPRL:
1238                 err = -EINVAL;
1239                 if (dev == sitn->fb_tunnel_dev)
1240                         goto done;
1241                 err = -ENOENT;
1242                 if (!(t = netdev_priv(dev)))
1243                         goto done;
1244                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1245                 break;
1246
1247         case SIOCADDPRL:
1248         case SIOCDELPRL:
1249         case SIOCCHGPRL:
1250                 err = -EPERM;
1251                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1252                         goto done;
1253                 err = -EINVAL;
1254                 if (dev == sitn->fb_tunnel_dev)
1255                         goto done;
1256                 err = -EFAULT;
1257                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1258                         goto done;
1259                 err = -ENOENT;
1260                 if (!(t = netdev_priv(dev)))
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                 netdev_state_change(dev);
1273                 break;
1274
1275 #ifdef CONFIG_IPV6_SIT_6RD
1276         case SIOCADD6RD:
1277         case SIOCCHG6RD:
1278         case SIOCDEL6RD:
1279                 err = -EPERM;
1280                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1281                         goto done;
1282
1283                 err = -EFAULT;
1284                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1285                                    sizeof(ip6rd)))
1286                         goto done;
1287
1288                 t = netdev_priv(dev);
1289
1290                 if (cmd != SIOCDEL6RD) {
1291                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1292                         if (err < 0)
1293                                 goto done;
1294                 } else
1295                         ipip6_tunnel_clone_6rd(dev, sitn);
1296
1297                 err = 0;
1298                 break;
1299 #endif
1300
1301         default:
1302                 err = -EINVAL;
1303         }
1304
1305 done:
1306         return err;
1307 }
1308
1309 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1310 {
1311         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1312                 return -EINVAL;
1313         dev->mtu = new_mtu;
1314         return 0;
1315 }
1316
1317 static const struct net_device_ops ipip6_netdev_ops = {
1318         .ndo_uninit     = ipip6_tunnel_uninit,
1319         .ndo_start_xmit = sit_tunnel_xmit,
1320         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1321         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1322         .ndo_get_stats64 = ip_tunnel_get_stats64,
1323 };
1324
1325 static void ipip6_dev_free(struct net_device *dev)
1326 {
1327         free_percpu(dev->tstats);
1328         free_netdev(dev);
1329 }
1330
1331 #define SIT_FEATURES (NETIF_F_SG           | \
1332                       NETIF_F_FRAGLIST     | \
1333                       NETIF_F_HIGHDMA      | \
1334                       NETIF_F_GSO_SOFTWARE | \
1335                       NETIF_F_HW_CSUM)
1336
1337 static void ipip6_tunnel_setup(struct net_device *dev)
1338 {
1339         dev->netdev_ops         = &ipip6_netdev_ops;
1340         dev->destructor         = ipip6_dev_free;
1341
1342         dev->type               = ARPHRD_SIT;
1343         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1344         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1345         dev->flags              = IFF_NOARP;
1346         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1347         dev->iflink             = 0;
1348         dev->addr_len           = 4;
1349         dev->features           |= NETIF_F_LLTX;
1350         dev->features           |= SIT_FEATURES;
1351         dev->hw_features        |= SIT_FEATURES;
1352 }
1353
1354 static int ipip6_tunnel_init(struct net_device *dev)
1355 {
1356         struct ip_tunnel *tunnel = netdev_priv(dev);
1357         int i;
1358
1359         tunnel->dev = dev;
1360         tunnel->net = dev_net(dev);
1361
1362         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1363         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1364
1365         ipip6_tunnel_bind_dev(dev);
1366         dev->tstats = alloc_percpu(struct pcpu_tstats);
1367         if (!dev->tstats)
1368                 return -ENOMEM;
1369
1370         for_each_possible_cpu(i) {
1371                 struct pcpu_tstats *ipip6_tunnel_stats;
1372                 ipip6_tunnel_stats = per_cpu_ptr(dev->tstats, i);
1373                 u64_stats_init(&ipip6_tunnel_stats->syncp);
1374         }
1375
1376         return 0;
1377 }
1378
1379 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1380 {
1381         struct ip_tunnel *tunnel = netdev_priv(dev);
1382         struct iphdr *iph = &tunnel->parms.iph;
1383         struct net *net = dev_net(dev);
1384         struct sit_net *sitn = net_generic(net, sit_net_id);
1385         int i;
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 = alloc_percpu(struct pcpu_tstats);
1397         if (!dev->tstats)
1398                 return -ENOMEM;
1399
1400         for_each_possible_cpu(i) {
1401                 struct pcpu_tstats *ipip6_fb_stats;
1402                 ipip6_fb_stats = per_cpu_ptr(dev->tstats, i);
1403                 u64_stats_init(&ipip6_fb_stats->syncp);
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                                            ipip6_tunnel_setup);
1734         if (!sitn->fb_tunnel_dev) {
1735                 err = -ENOMEM;
1736                 goto err_alloc_dev;
1737         }
1738         dev_net_set(sitn->fb_tunnel_dev, net);
1739         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1740         /* FB netdevice is special: we have one, and only one per netns.
1741          * Allowing to move it to another netns is clearly unsafe.
1742          */
1743         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1744
1745         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1746         if (err)
1747                 goto err_dev_free;
1748
1749         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1750
1751         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1752                 goto err_reg_dev;
1753
1754         t = netdev_priv(sitn->fb_tunnel_dev);
1755
1756         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1757         return 0;
1758
1759 err_reg_dev:
1760         dev_put(sitn->fb_tunnel_dev);
1761 err_dev_free:
1762         ipip6_dev_free(sitn->fb_tunnel_dev);
1763 err_alloc_dev:
1764         return err;
1765 }
1766
1767 static void __net_exit sit_exit_net(struct net *net)
1768 {
1769         LIST_HEAD(list);
1770
1771         rtnl_lock();
1772         sit_destroy_tunnels(net, &list);
1773         unregister_netdevice_many(&list);
1774         rtnl_unlock();
1775 }
1776
1777 static struct pernet_operations sit_net_ops = {
1778         .init = sit_init_net,
1779         .exit = sit_exit_net,
1780         .id   = &sit_net_id,
1781         .size = sizeof(struct sit_net),
1782 };
1783
1784 static void __exit sit_cleanup(void)
1785 {
1786         rtnl_link_unregister(&sit_link_ops);
1787         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1788         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1789
1790         unregister_pernet_device(&sit_net_ops);
1791         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1792 }
1793
1794 static int __init sit_init(void)
1795 {
1796         int err;
1797
1798         pr_info("IPv6 over IPv4 tunneling driver\n");
1799
1800         err = register_pernet_device(&sit_net_ops);
1801         if (err < 0)
1802                 return err;
1803         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1804         if (err < 0) {
1805                 pr_info("%s: can't register ip6ip4\n", __func__);
1806                 goto xfrm_tunnel_failed;
1807         }
1808         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1809         if (err < 0) {
1810                 pr_info("%s: can't register ip4ip4\n", __func__);
1811                 goto xfrm_tunnel4_failed;
1812         }
1813         err = rtnl_link_register(&sit_link_ops);
1814         if (err < 0)
1815                 goto rtnl_link_failed;
1816
1817 out:
1818         return err;
1819
1820 rtnl_link_failed:
1821         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1822 xfrm_tunnel4_failed:
1823         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1824 xfrm_tunnel_failed:
1825         unregister_pernet_device(&sit_net_ops);
1826         goto out;
1827 }
1828
1829 module_init(sit_init);
1830 module_exit(sit_cleanup);
1831 MODULE_LICENSE("GPL");
1832 MODULE_ALIAS_NETDEV("sit0");