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/ipip.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 int ipip6_tunnel_init(struct net_device *dev);
  69 static void ipip6_tunnel_setup(struct net_device *dev);
  70 static void ipip6_dev_free(struct net_device *dev);
  71
  72 static int sit_net_id __read_mostly;
  73 struct sit_net {
  74         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  75         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  76         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  77         struct ip_tunnel __rcu *tunnels_wc[1];
  78         struct ip_tunnel __rcu **tunnels[4];
  79
  80         struct net_device *fb_tunnel_dev;
  81 };
  82
  83 /*
  84  * Locking : hash tables are protected by RCU and RTNL
  85  */
  86
  87 #define for_each_ip_tunnel_rcu(start) \
  88         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
  89
  90 /* often modified stats are per cpu, other are shared (netdev->stats) */
  91 struct pcpu_tstats {
  92         u64     rx_packets;
  93         u64     rx_bytes;
  94         u64     tx_packets;
  95         u64     tx_bytes;
  96         struct u64_stats_sync   syncp;
  97 };
  98
  99 static struct rtnl_link_stats64 *ipip6_get_stats64(struct net_device *dev,
 100                                                    struct rtnl_link_stats64 *tot)
 101 {
 102         int i;
 103
 104         for_each_possible_cpu(i) {
 105                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 106                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 107                 unsigned int start;
 108
 109                 do {
 110                         start = u64_stats_fetch_begin_bh(&tstats->syncp);
 111                         rx_packets = tstats->rx_packets;
 112                         tx_packets = tstats->tx_packets;
 113                         rx_bytes = tstats->rx_bytes;
 114                         tx_bytes = tstats->tx_bytes;
 115                 } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
 116
 117                 tot->rx_packets += rx_packets;
 118                 tot->tx_packets += tx_packets;
 119                 tot->rx_bytes   += rx_bytes;
 120                 tot->tx_bytes   += tx_bytes;
 121         }
 122
 123         tot->rx_errors = dev->stats.rx_errors;
 124         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 125         tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
 126         tot->tx_dropped = dev->stats.tx_dropped;
 127         tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
 128         tot->tx_errors = dev->stats.tx_errors;
 129
 130         return tot;
 131 }
 132
 133 /*
 134  * Must be invoked with rcu_read_lock
 135  */
 136 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
 137                 struct net_device *dev, __be32 remote, __be32 local)
 138 {
 139         unsigned int h0 = HASH(remote);
 140         unsigned int h1 = HASH(local);
 141         struct ip_tunnel *t;
 142         struct sit_net *sitn = net_generic(net, sit_net_id);
 143
 144         for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
 145                 if (local == t->parms.iph.saddr &&
 146                     remote == t->parms.iph.daddr &&
 147                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 148                     (t->dev->flags & IFF_UP))
 149                         return t;
 150         }
 151         for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
 152                 if (remote == t->parms.iph.daddr &&
 153                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 154                     (t->dev->flags & IFF_UP))
 155                         return t;
 156         }
 157         for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
 158                 if (local == t->parms.iph.saddr &&
 159                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 160                     (t->dev->flags & IFF_UP))
 161                         return t;
 162         }
 163         t = rcu_dereference(sitn->tunnels_wc[0]);
 164         if ((t != NULL) && (t->dev->flags & IFF_UP))
 165                 return t;
 166         return NULL;
 167 }
 168
 169 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 170                 struct ip_tunnel_parm *parms)
 171 {
 172         __be32 remote = parms->iph.daddr;
 173         __be32 local = parms->iph.saddr;
 174         unsigned int h = 0;
 175         int prio = 0;
 176
 177         if (remote) {
 178                 prio |= 2;
 179                 h ^= HASH(remote);
 180         }
 181         if (local) {
 182                 prio |= 1;
 183                 h ^= HASH(local);
 184         }
 185         return &sitn->tunnels[prio][h];
 186 }
 187
 188 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 189                 struct ip_tunnel *t)
 190 {
 191         return __ipip6_bucket(sitn, &t->parms);
 192 }
 193
 194 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 195 {
 196         struct ip_tunnel __rcu **tp;
 197         struct ip_tunnel *iter;
 198
 199         for (tp = ipip6_bucket(sitn, t);
 200              (iter = rtnl_dereference(*tp)) != NULL;
 201              tp = &iter->next) {
 202                 if (t == iter) {
 203                         rcu_assign_pointer(*tp, t->next);
 204                         break;
 205                 }
 206         }
 207 }
 208
 209 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 210 {
 211         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 212
 213         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 214         rcu_assign_pointer(*tp, t);
 215 }
 216
 217 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 218 {
 219 #ifdef CONFIG_IPV6_SIT_6RD
 220         struct ip_tunnel *t = netdev_priv(dev);
 221
 222         if (t->dev == sitn->fb_tunnel_dev) {
 223                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 224                 t->ip6rd.relay_prefix = 0;
 225                 t->ip6rd.prefixlen = 16;
 226                 t->ip6rd.relay_prefixlen = 0;
 227         } else {
 228                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 229                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 230         }
 231 #endif
 232 }
 233
 234 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 235                 struct ip_tunnel_parm *parms, int create)
 236 {
 237         __be32 remote = parms->iph.daddr;
 238         __be32 local = parms->iph.saddr;
 239         struct ip_tunnel *t, *nt;
 240         struct ip_tunnel __rcu **tp;
 241         struct net_device *dev;
 242         char name[IFNAMSIZ];
 243         struct sit_net *sitn = net_generic(net, sit_net_id);
 244
 245         for (tp = __ipip6_bucket(sitn, parms);
 246             (t = rtnl_dereference(*tp)) != NULL;
 247              tp = &t->next) {
 248                 if (local == t->parms.iph.saddr &&
 249                     remote == t->parms.iph.daddr &&
 250                     parms->link == t->parms.link) {
 251                         if (create)
 252                                 return NULL;
 253                         else
 254                                 return t;
 255                 }
 256         }
 257         if (!create)
 258                 goto failed;
 259
 260         if (parms->name[0])
 261                 strlcpy(name, parms->name, IFNAMSIZ);
 262         else
 263                 strcpy(name, "sit%d");
 264
 265         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 266         if (dev == NULL)
 267                 return NULL;
 268
 269         dev_net_set(dev, net);
 270
 271         nt = netdev_priv(dev);
 272
 273         nt->parms = *parms;
 274         if (ipip6_tunnel_init(dev) < 0)
 275                 goto failed_free;
 276         ipip6_tunnel_clone_6rd(dev, sitn);
 277
 278         if (parms->i_flags & SIT_ISATAP)
 279                 dev->priv_flags |= IFF_ISATAP;
 280
 281         if (register_netdevice(dev) < 0)
 282                 goto failed_free;
 283
 284         strcpy(nt->parms.name, dev->name);
 285
 286         dev_hold(dev);
 287
 288         ipip6_tunnel_link(sitn, nt);
 289         return nt;
 290
 291 failed_free:
 292         ipip6_dev_free(dev);
 293 failed:
 294         return NULL;
 295 }
 296
 297 #define for_each_prl_rcu(start)                 \
 298         for (prl = rcu_dereference(start);      \
 299              prl;                               \
 300              prl = rcu_dereference(prl->next))
 301
 302 static struct ip_tunnel_prl_entry *
 303 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 304 {
 305         struct ip_tunnel_prl_entry *prl;
 306
 307         for_each_prl_rcu(t->prl)
 308                 if (prl->addr == addr)
 309                         break;
 310         return prl;
 311
 312 }
 313
 314 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 315                                 struct ip_tunnel_prl __user *a)
 316 {
 317         struct ip_tunnel_prl kprl, *kp;
 318         struct ip_tunnel_prl_entry *prl;
 319         unsigned int cmax, c = 0, ca, len;
 320         int ret = 0;
 321
 322         if (copy_from_user(&kprl, a, sizeof(kprl)))
 323                 return -EFAULT;
 324         cmax = kprl.datalen / sizeof(kprl);
 325         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 326                 cmax = 1;
 327
 328         /* For simple GET or for root users,
 329          * we try harder to allocate.
 330          */
 331         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 332                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 333                 NULL;
 334
 335         rcu_read_lock();
 336
 337         ca = t->prl_count < cmax ? t->prl_count : cmax;
 338
 339         if (!kp) {
 340                 /* We don't try hard to allocate much memory for
 341                  * non-root users.
 342                  * For root users, retry allocating enough memory for
 343                  * the answer.
 344                  */
 345                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 346                 if (!kp) {
 347                         ret = -ENOMEM;
 348                         goto out;
 349                 }
 350         }
 351
 352         c = 0;
 353         for_each_prl_rcu(t->prl) {
 354                 if (c >= cmax)
 355                         break;
 356                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 357                         continue;
 358                 kp[c].addr = prl->addr;
 359                 kp[c].flags = prl->flags;
 360                 c++;
 361                 if (kprl.addr != htonl(INADDR_ANY))
 362                         break;
 363         }
 364 out:
 365         rcu_read_unlock();
 366
 367         len = sizeof(*kp) * c;
 368         ret = 0;
 369         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 370                 ret = -EFAULT;
 371
 372         kfree(kp);
 373
 374         return ret;
 375 }
 376
 377 static int
 378 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 379 {
 380         struct ip_tunnel_prl_entry *p;
 381         int err = 0;
 382
 383         if (a->addr == htonl(INADDR_ANY))
 384                 return -EINVAL;
 385
 386         ASSERT_RTNL();
 387
 388         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 389                 if (p->addr == a->addr) {
 390                         if (chg) {
 391                                 p->flags = a->flags;
 392                                 goto out;
 393                         }
 394                         err = -EEXIST;
 395                         goto out;
 396                 }
 397         }
 398
 399         if (chg) {
 400                 err = -ENXIO;
 401                 goto out;
 402         }
 403
 404         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 405         if (!p) {
 406                 err = -ENOBUFS;
 407                 goto out;
 408         }
 409
 410         p->next = t->prl;
 411         p->addr = a->addr;
 412         p->flags = a->flags;
 413         t->prl_count++;
 414         rcu_assign_pointer(t->prl, p);
 415 out:
 416         return err;
 417 }
 418
 419 static void prl_list_destroy_rcu(struct rcu_head *head)
 420 {
 421         struct ip_tunnel_prl_entry *p, *n;
 422
 423         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 424         do {
 425                 n = rcu_dereference_protected(p->next, 1);
 426                 kfree(p);
 427                 p = n;
 428         } while (p);
 429 }
 430
 431 static int
 432 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 433 {
 434         struct ip_tunnel_prl_entry *x;
 435         struct ip_tunnel_prl_entry __rcu **p;
 436         int err = 0;
 437
 438         ASSERT_RTNL();
 439
 440         if (a && a->addr != htonl(INADDR_ANY)) {
 441                 for (p = &t->prl;
 442                      (x = rtnl_dereference(*p)) != NULL;
 443                      p = &x->next) {
 444                         if (x->addr == a->addr) {
 445                                 *p = x->next;
 446                                 kfree_rcu(x, rcu_head);
 447                                 t->prl_count--;
 448                                 goto out;
 449                         }
 450                 }
 451                 err = -ENXIO;
 452         } else {
 453                 x = rtnl_dereference(t->prl);
 454                 if (x) {
 455                         t->prl_count = 0;
 456                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 457                         t->prl = NULL;
 458                 }
 459         }
 460 out:
 461         return err;
 462 }
 463
 464 static int
 465 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 466 {
 467         struct ip_tunnel_prl_entry *p;
 468         int ok = 1;
 469
 470         rcu_read_lock();
 471         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 472         if (p) {
 473                 if (p->flags & PRL_DEFAULT)
 474                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 475                 else
 476                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 477         } else {
 478                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 479
 480                 if (ipv6_addr_is_isatap(addr6) &&
 481                     (addr6->s6_addr32[3] == iph->saddr) &&
 482                     ipv6_chk_prefix(addr6, t->dev))
 483                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 484                 else
 485                         ok = 0;
 486         }
 487         rcu_read_unlock();
 488         return ok;
 489 }
 490
 491 static void ipip6_tunnel_uninit(struct net_device *dev)
 492 {
 493         struct net *net = dev_net(dev);
 494         struct sit_net *sitn = net_generic(net, sit_net_id);
 495
 496         if (dev == sitn->fb_tunnel_dev) {
 497                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 498         } else {
 499                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 500                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 501         }
 502         dev_put(dev);
 503 }
 504
 505
 506 static int ipip6_err(struct sk_buff *skb, u32 info)
 507 {
 508
 509 /* All the routers (except for Linux) return only
 510    8 bytes of packet payload. It means, that precise relaying of
 511    ICMP in the real Internet is absolutely infeasible.
 512  */
 513         const struct iphdr *iph = (const struct iphdr *)skb->data;
 514         const int type = icmp_hdr(skb)->type;
 515         const int code = icmp_hdr(skb)->code;
 516         struct ip_tunnel *t;
 517         int err;
 518
 519         switch (type) {
 520         default:
 521         case ICMP_PARAMETERPROB:
 522                 return 0;
 523
 524         case ICMP_DEST_UNREACH:
 525                 switch (code) {
 526                 case ICMP_SR_FAILED:
 527                 case ICMP_PORT_UNREACH:
 528                         /* Impossible event. */
 529                         return 0;
 530                 default:
 531                         /* All others are translated to HOST_UNREACH.
 532                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 533                            I believe they are just ether pollution. --ANK
 534                          */
 535                         break;
 536                 }
 537                 break;
 538         case ICMP_TIME_EXCEEDED:
 539                 if (code != ICMP_EXC_TTL)
 540                         return 0;
 541                 break;
 542         case ICMP_REDIRECT:
 543                 break;
 544         }
 545
 546         err = -ENOENT;
 547
 548         rcu_read_lock();
 549         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 550                                 skb->dev,
 551                                 iph->daddr,
 552                                 iph->saddr);
 553         if (t == NULL)
 554                 goto out;
 555
 556         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 557                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 558                                  t->dev->ifindex, 0, IPPROTO_IPV6, 0);
 559                 err = 0;
 560                 goto out;
 561         }
 562         if (type == ICMP_REDIRECT) {
 563                 ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
 564                               IPPROTO_IPV6, 0);
 565                 err = 0;
 566                 goto out;
 567         }
 568
 569         if (t->parms.iph.daddr == 0)
 570                 goto out;
 571
 572         err = 0;
 573         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 574                 goto out;
 575
 576         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 577                 t->err_count++;
 578         else
 579                 t->err_count = 1;
 580         t->err_time = jiffies;
 581 out:
 582         rcu_read_unlock();
 583         return err;
 584 }
 585
 586 static inline void ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 587 {
 588         if (INET_ECN_is_ce(iph->tos))
 589                 IP6_ECN_set_ce(ipv6_hdr(skb));
 590 }
 591
 592 static int ipip6_rcv(struct sk_buff *skb)
 593 {
 594         const struct iphdr *iph;
 595         struct ip_tunnel *tunnel;
 596
 597         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 598                 goto out;
 599
 600         iph = ip_hdr(skb);
 601
 602         rcu_read_lock();
 603         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 604                                      iph->saddr, iph->daddr);
 605         if (tunnel != NULL) {
 606                 struct pcpu_tstats *tstats;
 607
 608                 secpath_reset(skb);
 609                 skb->mac_header = skb->network_header;
 610                 skb_reset_network_header(skb);
 611                 IPCB(skb)->flags = 0;
 612                 skb->protocol = htons(ETH_P_IPV6);
 613                 skb->pkt_type = PACKET_HOST;
 614
 615                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 616                     !isatap_chksrc(skb, iph, tunnel)) {
 617                         tunnel->dev->stats.rx_errors++;
 618                         rcu_read_unlock();
 619                         kfree_skb(skb);
 620                         return 0;
 621                 }
 622
 623                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 624                 tstats->rx_packets++;
 625                 tstats->rx_bytes += skb->len;
 626
 627                 __skb_tunnel_rx(skb, tunnel->dev);
 628
 629                 ipip6_ecn_decapsulate(iph, skb);
 630
 631                 netif_rx(skb);
 632
 633                 rcu_read_unlock();
 634                 return 0;
 635         }
 636
 637         /* no tunnel matched,  let upstream know, ipsec may handle it */
 638         rcu_read_unlock();
 639         return 1;
 640 out:
 641         kfree_skb(skb);
 642         return 0;
 643 }
 644
 645 /*
 646  * Returns the embedded IPv4 address if the IPv6 address
 647  * comes from 6rd / 6to4 (RFC 3056) addr space.
 648  */
 649 static inline
 650 __be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 651 {
 652         __be32 dst = 0;
 653
 654 #ifdef CONFIG_IPV6_SIT_6RD
 655         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 656                               tunnel->ip6rd.prefixlen)) {
 657                 unsigned int pbw0, pbi0;
 658                 int pbi1;
 659                 u32 d;
 660
 661                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 662                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 663
 664                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 665                     tunnel->ip6rd.relay_prefixlen;
 666
 667                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 668                 if (pbi1 > 0)
 669                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 670                              (32 - pbi1);
 671
 672                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
 673         }
 674 #else
 675         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 676                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 677                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 678         }
 679 #endif
 680         return dst;
 681 }
 682
 683 /*
 684  *      This function assumes it is being called from dev_queue_xmit()
 685  *      and that skb is filled properly by that function.
 686  */
 687
 688 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 689                                      struct net_device *dev)
 690 {
 691         struct ip_tunnel *tunnel = netdev_priv(dev);
 692         struct pcpu_tstats *tstats;
 693         const struct iphdr  *tiph = &tunnel->parms.iph;
 694         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 695         u8     tos = tunnel->parms.iph.tos;
 696         __be16 df = tiph->frag_off;
 697         struct rtable *rt;                      /* Route to the other host */
 698         struct net_device *tdev;                /* Device to other host */
 699         struct iphdr  *iph;                     /* Our new IP header */
 700         unsigned int max_headroom;              /* The extra header space needed */
 701         __be32 dst = tiph->daddr;
 702         struct flowi4 fl4;
 703         int    mtu;
 704         const struct in6_addr *addr6;
 705         int addr_type;
 706
 707         if (skb->protocol != htons(ETH_P_IPV6))
 708                 goto tx_error;
 709
 710         if (tos == 1)
 711                 tos = ipv6_get_dsfield(iph6);
 712
 713         /* ISATAP (RFC4214) - must come before 6to4 */
 714         if (dev->priv_flags & IFF_ISATAP) {
 715                 struct neighbour *neigh = NULL;
 716                 bool do_tx_error = false;
 717
 718                 if (skb_dst(skb))
 719                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 720
 721                 if (neigh == NULL) {
 722                         net_dbg_ratelimited("sit: nexthop == NULL\n");
 723                         goto tx_error;
 724                 }
 725
 726                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 727                 addr_type = ipv6_addr_type(addr6);
 728
 729                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 730                      ipv6_addr_is_isatap(addr6))
 731                         dst = addr6->s6_addr32[3];
 732                 else
 733                         do_tx_error = true;
 734
 735                 neigh_release(neigh);
 736                 if (do_tx_error)
 737                         goto tx_error;
 738         }
 739
 740         if (!dst)
 741                 dst = try_6rd(&iph6->daddr, tunnel);
 742
 743         if (!dst) {
 744                 struct neighbour *neigh = NULL;
 745                 bool do_tx_error = false;
 746
 747                 if (skb_dst(skb))
 748                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 749
 750                 if (neigh == NULL) {
 751                         net_dbg_ratelimited("sit: nexthop == NULL\n");
 752                         goto tx_error;
 753                 }
 754
 755                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 756                 addr_type = ipv6_addr_type(addr6);
 757
 758                 if (addr_type == IPV6_ADDR_ANY) {
 759                         addr6 = &ipv6_hdr(skb)->daddr;
 760                         addr_type = ipv6_addr_type(addr6);
 761                 }
 762
 763                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 764                         dst = addr6->s6_addr32[3];
 765                 else
 766                         do_tx_error = true;
 767
 768                 neigh_release(neigh);
 769                 if (do_tx_error)
 770                         goto tx_error;
 771         }
 772
 773         rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 774                                    dst, tiph->saddr,
 775                                    0, 0,
 776                                    IPPROTO_IPV6, RT_TOS(tos),
 777                                    tunnel->parms.link);
 778         if (IS_ERR(rt)) {
 779                 dev->stats.tx_carrier_errors++;
 780                 goto tx_error_icmp;
 781         }
 782         if (rt->rt_type != RTN_UNICAST) {
 783                 ip_rt_put(rt);
 784                 dev->stats.tx_carrier_errors++;
 785                 goto tx_error_icmp;
 786         }
 787         tdev = rt->dst.dev;
 788
 789         if (tdev == dev) {
 790                 ip_rt_put(rt);
 791                 dev->stats.collisions++;
 792                 goto tx_error;
 793         }
 794
 795         if (df) {
 796                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 797
 798                 if (mtu < 68) {
 799                         dev->stats.collisions++;
 800                         ip_rt_put(rt);
 801                         goto tx_error;
 802                 }
 803
 804                 if (mtu < IPV6_MIN_MTU) {
 805                         mtu = IPV6_MIN_MTU;
 806                         df = 0;
 807                 }
 808
 809                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 810                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 811
 812                 if (skb->len > mtu) {
 813                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 814                         ip_rt_put(rt);
 815                         goto tx_error;
 816                 }
 817         }
 818
 819         if (tunnel->err_count > 0) {
 820                 if (time_before(jiffies,
 821                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 822                         tunnel->err_count--;
 823                         dst_link_failure(skb);
 824                 } else
 825                         tunnel->err_count = 0;
 826         }
 827
 828         /*
 829          * Okay, now see if we can stuff it in the buffer as-is.
 830          */
 831         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 832
 833         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 834             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 835                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 836                 if (!new_skb) {
 837                         ip_rt_put(rt);
 838                         dev->stats.tx_dropped++;
 839                         dev_kfree_skb(skb);
 840                         return NETDEV_TX_OK;
 841                 }
 842                 if (skb->sk)
 843                         skb_set_owner_w(new_skb, skb->sk);
 844                 dev_kfree_skb(skb);
 845                 skb = new_skb;
 846                 iph6 = ipv6_hdr(skb);
 847         }
 848
 849         skb->transport_header = skb->network_header;
 850         skb_push(skb, sizeof(struct iphdr));
 851         skb_reset_network_header(skb);
 852         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 853         IPCB(skb)->flags = 0;
 854         skb_dst_drop(skb);
 855         skb_dst_set(skb, &rt->dst);
 856
 857         /*
 858          *      Push down and install the IPIP header.
 859          */
 860
 861         iph                     =       ip_hdr(skb);
 862         iph->version            =       4;
 863         iph->ihl                =       sizeof(struct iphdr)>>2;
 864         iph->frag_off           =       df;
 865         iph->protocol           =       IPPROTO_IPV6;
 866         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 867         iph->daddr              =       fl4.daddr;
 868         iph->saddr              =       fl4.saddr;
 869
 870         if ((iph->ttl = tiph->ttl) == 0)
 871                 iph->ttl        =       iph6->hop_limit;
 872
 873         nf_reset(skb);
 874         tstats = this_cpu_ptr(dev->tstats);
 875         __IPTUNNEL_XMIT(tstats, &dev->stats);
 876         return NETDEV_TX_OK;
 877
 878 tx_error_icmp:
 879         dst_link_failure(skb);
 880 tx_error:
 881         dev->stats.tx_errors++;
 882         dev_kfree_skb(skb);
 883         return NETDEV_TX_OK;
 884 }
 885
 886 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 887 {
 888         struct net_device *tdev = NULL;
 889         struct ip_tunnel *tunnel;
 890         const struct iphdr *iph;
 891         struct flowi4 fl4;
 892
 893         tunnel = netdev_priv(dev);
 894         iph = &tunnel->parms.iph;
 895
 896         if (iph->daddr) {
 897                 struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 898                                                           iph->daddr, iph->saddr,
 899                                                           0, 0,
 900                                                           IPPROTO_IPV6,
 901                                                           RT_TOS(iph->tos),
 902                                                           tunnel->parms.link);
 903
 904                 if (!IS_ERR(rt)) {
 905                         tdev = rt->dst.dev;
 906                         ip_rt_put(rt);
 907                 }
 908                 dev->flags |= IFF_POINTOPOINT;
 909         }
 910
 911         if (!tdev && tunnel->parms.link)
 912                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 913
 914         if (tdev) {
 915                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 916                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 917                 if (dev->mtu < IPV6_MIN_MTU)
 918                         dev->mtu = IPV6_MIN_MTU;
 919         }
 920         dev->iflink = tunnel->parms.link;
 921 }
 922
 923 static int
 924 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 925 {
 926         int err = 0;
 927         struct ip_tunnel_parm p;
 928         struct ip_tunnel_prl prl;
 929         struct ip_tunnel *t;
 930         struct net *net = dev_net(dev);
 931         struct sit_net *sitn = net_generic(net, sit_net_id);
 932 #ifdef CONFIG_IPV6_SIT_6RD
 933         struct ip_tunnel_6rd ip6rd;
 934 #endif
 935
 936         switch (cmd) {
 937         case SIOCGETTUNNEL:
 938 #ifdef CONFIG_IPV6_SIT_6RD
 939         case SIOCGET6RD:
 940 #endif
 941                 t = NULL;
 942                 if (dev == sitn->fb_tunnel_dev) {
 943                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 944                                 err = -EFAULT;
 945                                 break;
 946                         }
 947                         t = ipip6_tunnel_locate(net, &p, 0);
 948                 }
 949                 if (t == NULL)
 950                         t = netdev_priv(dev);
 951
 952                 err = -EFAULT;
 953                 if (cmd == SIOCGETTUNNEL) {
 954                         memcpy(&p, &t->parms, sizeof(p));
 955                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
 956                                          sizeof(p)))
 957                                 goto done;
 958 #ifdef CONFIG_IPV6_SIT_6RD
 959                 } else {
 960                         ip6rd.prefix = t->ip6rd.prefix;
 961                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
 962                         ip6rd.prefixlen = t->ip6rd.prefixlen;
 963                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
 964                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
 965                                          sizeof(ip6rd)))
 966                                 goto done;
 967 #endif
 968                 }
 969                 err = 0;
 970                 break;
 971
 972         case SIOCADDTUNNEL:
 973         case SIOCCHGTUNNEL:
 974                 err = -EPERM;
 975                 if (!capable(CAP_NET_ADMIN))
 976                         goto done;
 977
 978                 err = -EFAULT;
 979                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 980                         goto done;
 981
 982                 err = -EINVAL;
 983                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 984                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 985                         goto done;
 986                 if (p.iph.ttl)
 987                         p.iph.frag_off |= htons(IP_DF);
 988
 989                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 990
 991                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 992                         if (t != NULL) {
 993                                 if (t->dev != dev) {
 994                                         err = -EEXIST;
 995                                         break;
 996                                 }
 997                         } else {
 998                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 999                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1000                                         err = -EINVAL;
1001                                         break;
1002                                 }
1003                                 t = netdev_priv(dev);
1004                                 ipip6_tunnel_unlink(sitn, t);
1005                                 synchronize_net();
1006                                 t->parms.iph.saddr = p.iph.saddr;
1007                                 t->parms.iph.daddr = p.iph.daddr;
1008                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1009                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
1010                                 ipip6_tunnel_link(sitn, t);
1011                                 netdev_state_change(dev);
1012                         }
1013                 }
1014
1015                 if (t) {
1016                         err = 0;
1017                         if (cmd == SIOCCHGTUNNEL) {
1018                                 t->parms.iph.ttl = p.iph.ttl;
1019                                 t->parms.iph.tos = p.iph.tos;
1020                                 if (t->parms.link != p.link) {
1021                                         t->parms.link = p.link;
1022                                         ipip6_tunnel_bind_dev(dev);
1023                                         netdev_state_change(dev);
1024                                 }
1025                         }
1026                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1027                                 err = -EFAULT;
1028                 } else
1029                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1030                 break;
1031
1032         case SIOCDELTUNNEL:
1033                 err = -EPERM;
1034                 if (!capable(CAP_NET_ADMIN))
1035                         goto done;
1036
1037                 if (dev == sitn->fb_tunnel_dev) {
1038                         err = -EFAULT;
1039                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1040                                 goto done;
1041                         err = -ENOENT;
1042                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1043                                 goto done;
1044                         err = -EPERM;
1045                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1046                                 goto done;
1047                         dev = t->dev;
1048                 }
1049                 unregister_netdevice(dev);
1050                 err = 0;
1051                 break;
1052
1053         case SIOCGETPRL:
1054                 err = -EINVAL;
1055                 if (dev == sitn->fb_tunnel_dev)
1056                         goto done;
1057                 err = -ENOENT;
1058                 if (!(t = netdev_priv(dev)))
1059                         goto done;
1060                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1061                 break;
1062
1063         case SIOCADDPRL:
1064         case SIOCDELPRL:
1065         case SIOCCHGPRL:
1066                 err = -EPERM;
1067                 if (!capable(CAP_NET_ADMIN))
1068                         goto done;
1069                 err = -EINVAL;
1070                 if (dev == sitn->fb_tunnel_dev)
1071                         goto done;
1072                 err = -EFAULT;
1073                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1074                         goto done;
1075                 err = -ENOENT;
1076                 if (!(t = netdev_priv(dev)))
1077                         goto done;
1078
1079                 switch (cmd) {
1080                 case SIOCDELPRL:
1081                         err = ipip6_tunnel_del_prl(t, &prl);
1082                         break;
1083                 case SIOCADDPRL:
1084                 case SIOCCHGPRL:
1085                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1086                         break;
1087                 }
1088                 netdev_state_change(dev);
1089                 break;
1090
1091 #ifdef CONFIG_IPV6_SIT_6RD
1092         case SIOCADD6RD:
1093         case SIOCCHG6RD:
1094         case SIOCDEL6RD:
1095                 err = -EPERM;
1096                 if (!capable(CAP_NET_ADMIN))
1097                         goto done;
1098
1099                 err = -EFAULT;
1100                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1101                                    sizeof(ip6rd)))
1102                         goto done;
1103
1104                 t = netdev_priv(dev);
1105
1106                 if (cmd != SIOCDEL6RD) {
1107                         struct in6_addr prefix;
1108                         __be32 relay_prefix;
1109
1110                         err = -EINVAL;
1111                         if (ip6rd.relay_prefixlen > 32 ||
1112                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1113                                 goto done;
1114
1115                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1116                                          ip6rd.prefixlen);
1117                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1118                                 goto done;
1119                         if (ip6rd.relay_prefixlen)
1120                                 relay_prefix = ip6rd.relay_prefix &
1121                                                htonl(0xffffffffUL <<
1122                                                      (32 - ip6rd.relay_prefixlen));
1123                         else
1124                                 relay_prefix = 0;
1125                         if (relay_prefix != ip6rd.relay_prefix)
1126                                 goto done;
1127
1128                         t->ip6rd.prefix = prefix;
1129                         t->ip6rd.relay_prefix = relay_prefix;
1130                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1131                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1132                 } else
1133                         ipip6_tunnel_clone_6rd(dev, sitn);
1134
1135                 err = 0;
1136                 break;
1137 #endif
1138
1139         default:
1140                 err = -EINVAL;
1141         }
1142
1143 done:
1144         return err;
1145 }
1146
1147 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1148 {
1149         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1150                 return -EINVAL;
1151         dev->mtu = new_mtu;
1152         return 0;
1153 }
1154
1155 static const struct net_device_ops ipip6_netdev_ops = {
1156         .ndo_uninit     = ipip6_tunnel_uninit,
1157         .ndo_start_xmit = ipip6_tunnel_xmit,
1158         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1159         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1160         .ndo_get_stats64= ipip6_get_stats64,
1161 };
1162
1163 static void ipip6_dev_free(struct net_device *dev)
1164 {
1165         free_percpu(dev->tstats);
1166         free_netdev(dev);
1167 }
1168
1169 static void ipip6_tunnel_setup(struct net_device *dev)
1170 {
1171         dev->netdev_ops         = &ipip6_netdev_ops;
1172         dev->destructor         = ipip6_dev_free;
1173
1174         dev->type               = ARPHRD_SIT;
1175         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1176         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1177         dev->flags              = IFF_NOARP;
1178         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1179         dev->iflink             = 0;
1180         dev->addr_len           = 4;
1181         dev->features           |= NETIF_F_NETNS_LOCAL;
1182         dev->features           |= NETIF_F_LLTX;
1183 }
1184
1185 static int ipip6_tunnel_init(struct net_device *dev)
1186 {
1187         struct ip_tunnel *tunnel = netdev_priv(dev);
1188
1189         tunnel->dev = dev;
1190
1191         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1192         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1193
1194         ipip6_tunnel_bind_dev(dev);
1195         dev->tstats = alloc_percpu(struct pcpu_tstats);
1196         if (!dev->tstats)
1197                 return -ENOMEM;
1198
1199         return 0;
1200 }
1201
1202 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1203 {
1204         struct ip_tunnel *tunnel = netdev_priv(dev);
1205         struct iphdr *iph = &tunnel->parms.iph;
1206         struct net *net = dev_net(dev);
1207         struct sit_net *sitn = net_generic(net, sit_net_id);
1208
1209         tunnel->dev = dev;
1210         strcpy(tunnel->parms.name, dev->name);
1211
1212         iph->version            = 4;
1213         iph->protocol           = IPPROTO_IPV6;
1214         iph->ihl                = 5;
1215         iph->ttl                = 64;
1216
1217         dev->tstats = alloc_percpu(struct pcpu_tstats);
1218         if (!dev->tstats)
1219                 return -ENOMEM;
1220         dev_hold(dev);
1221         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1222         return 0;
1223 }
1224
1225 static struct xfrm_tunnel sit_handler __read_mostly = {
1226         .handler        =       ipip6_rcv,
1227         .err_handler    =       ipip6_err,
1228         .priority       =       1,
1229 };
1230
1231 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1232 {
1233         int prio;
1234
1235         for (prio = 1; prio < 4; prio++) {
1236                 int h;
1237                 for (h = 0; h < HASH_SIZE; h++) {
1238                         struct ip_tunnel *t;
1239
1240                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1241                         while (t != NULL) {
1242                                 unregister_netdevice_queue(t->dev, head);
1243                                 t = rtnl_dereference(t->next);
1244                         }
1245                 }
1246         }
1247 }
1248
1249 static int __net_init sit_init_net(struct net *net)
1250 {
1251         struct sit_net *sitn = net_generic(net, sit_net_id);
1252         struct ip_tunnel *t;
1253         int err;
1254
1255         sitn->tunnels[0] = sitn->tunnels_wc;
1256         sitn->tunnels[1] = sitn->tunnels_l;
1257         sitn->tunnels[2] = sitn->tunnels_r;
1258         sitn->tunnels[3] = sitn->tunnels_r_l;
1259
1260         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1261                                            ipip6_tunnel_setup);
1262         if (!sitn->fb_tunnel_dev) {
1263                 err = -ENOMEM;
1264                 goto err_alloc_dev;
1265         }
1266         dev_net_set(sitn->fb_tunnel_dev, net);
1267
1268         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1269         if (err)
1270                 goto err_dev_free;
1271
1272         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1273
1274         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1275                 goto err_reg_dev;
1276
1277         t = netdev_priv(sitn->fb_tunnel_dev);
1278
1279         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1280         return 0;
1281
1282 err_reg_dev:
1283         dev_put(sitn->fb_tunnel_dev);
1284 err_dev_free:
1285         ipip6_dev_free(sitn->fb_tunnel_dev);
1286 err_alloc_dev:
1287         return err;
1288 }
1289
1290 static void __net_exit sit_exit_net(struct net *net)
1291 {
1292         struct sit_net *sitn = net_generic(net, sit_net_id);
1293         LIST_HEAD(list);
1294
1295         rtnl_lock();
1296         sit_destroy_tunnels(sitn, &list);
1297         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1298         unregister_netdevice_many(&list);
1299         rtnl_unlock();
1300 }
1301
1302 static struct pernet_operations sit_net_ops = {
1303         .init = sit_init_net,
1304         .exit = sit_exit_net,
1305         .id   = &sit_net_id,
1306         .size = sizeof(struct sit_net),
1307 };
1308
1309 static void __exit sit_cleanup(void)
1310 {
1311         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1312
1313         unregister_pernet_device(&sit_net_ops);
1314         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1315 }
1316
1317 static int __init sit_init(void)
1318 {
1319         int err;
1320
1321         pr_info("IPv6 over IPv4 tunneling driver\n");
1322
1323         err = register_pernet_device(&sit_net_ops);
1324         if (err < 0)
1325                 return err;
1326         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1327         if (err < 0) {
1328                 unregister_pernet_device(&sit_net_ops);
1329                 pr_info("%s: can't add protocol\n", __func__);
1330         }
1331         return err;
1332 }
1333
1334 module_init(sit_init);
1335 module_exit(sit_cleanup);
1336 MODULE_LICENSE("GPL");
1337 MODULE_ALIAS_NETDEV("sit0");