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         }
 543
 544         err = -ENOENT;
 545
 546         rcu_read_lock();
 547         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 548                                 skb->dev,
 549                                 iph->daddr,
 550                                 iph->saddr);
 551         if (t == NULL)
 552                 goto out;
 553
 554         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 555                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 556                                  t->dev->ifindex, 0, IPPROTO_IPV6, 0);
 557                 err = 0;
 558                 goto out;
 559         }
 560
 561         if (t->parms.iph.daddr == 0)
 562                 goto out;
 563
 564         err = 0;
 565         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 566                 goto out;
 567
 568         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 569                 t->err_count++;
 570         else
 571                 t->err_count = 1;
 572         t->err_time = jiffies;
 573 out:
 574         rcu_read_unlock();
 575         return err;
 576 }
 577
 578 static inline void ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 579 {
 580         if (INET_ECN_is_ce(iph->tos))
 581                 IP6_ECN_set_ce(ipv6_hdr(skb));
 582 }
 583
 584 static int ipip6_rcv(struct sk_buff *skb)
 585 {
 586         const struct iphdr *iph;
 587         struct ip_tunnel *tunnel;
 588
 589         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 590                 goto out;
 591
 592         iph = ip_hdr(skb);
 593
 594         rcu_read_lock();
 595         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 596                                      iph->saddr, iph->daddr);
 597         if (tunnel != NULL) {
 598                 struct pcpu_tstats *tstats;
 599
 600                 secpath_reset(skb);
 601                 skb->mac_header = skb->network_header;
 602                 skb_reset_network_header(skb);
 603                 IPCB(skb)->flags = 0;
 604                 skb->protocol = htons(ETH_P_IPV6);
 605                 skb->pkt_type = PACKET_HOST;
 606
 607                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 608                     !isatap_chksrc(skb, iph, tunnel)) {
 609                         tunnel->dev->stats.rx_errors++;
 610                         rcu_read_unlock();
 611                         kfree_skb(skb);
 612                         return 0;
 613                 }
 614
 615                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 616                 tstats->rx_packets++;
 617                 tstats->rx_bytes += skb->len;
 618
 619                 __skb_tunnel_rx(skb, tunnel->dev);
 620
 621                 ipip6_ecn_decapsulate(iph, skb);
 622
 623                 netif_rx(skb);
 624
 625                 rcu_read_unlock();
 626                 return 0;
 627         }
 628
 629         /* no tunnel matched,  let upstream know, ipsec may handle it */
 630         rcu_read_unlock();
 631         return 1;
 632 out:
 633         kfree_skb(skb);
 634         return 0;
 635 }
 636
 637 /*
 638  * Returns the embedded IPv4 address if the IPv6 address
 639  * comes from 6rd / 6to4 (RFC 3056) addr space.
 640  */
 641 static inline
 642 __be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 643 {
 644         __be32 dst = 0;
 645
 646 #ifdef CONFIG_IPV6_SIT_6RD
 647         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 648                               tunnel->ip6rd.prefixlen)) {
 649                 unsigned int pbw0, pbi0;
 650                 int pbi1;
 651                 u32 d;
 652
 653                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 654                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 655
 656                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 657                     tunnel->ip6rd.relay_prefixlen;
 658
 659                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 660                 if (pbi1 > 0)
 661                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 662                              (32 - pbi1);
 663
 664                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
 665         }
 666 #else
 667         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 668                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 669                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 670         }
 671 #endif
 672         return dst;
 673 }
 674
 675 /*
 676  *      This function assumes it is being called from dev_queue_xmit()
 677  *      and that skb is filled properly by that function.
 678  */
 679
 680 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 681                                      struct net_device *dev)
 682 {
 683         struct ip_tunnel *tunnel = netdev_priv(dev);
 684         struct pcpu_tstats *tstats;
 685         const struct iphdr  *tiph = &tunnel->parms.iph;
 686         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 687         u8     tos = tunnel->parms.iph.tos;
 688         __be16 df = tiph->frag_off;
 689         struct rtable *rt;                      /* Route to the other host */
 690         struct net_device *tdev;                /* Device to other host */
 691         struct iphdr  *iph;                     /* Our new IP header */
 692         unsigned int max_headroom;              /* The extra header space needed */
 693         __be32 dst = tiph->daddr;
 694         struct flowi4 fl4;
 695         int    mtu;
 696         const struct in6_addr *addr6;
 697         int addr_type;
 698
 699         if (skb->protocol != htons(ETH_P_IPV6))
 700                 goto tx_error;
 701
 702         if (tos == 1)
 703                 tos = ipv6_get_dsfield(iph6);
 704
 705         /* ISATAP (RFC4214) - must come before 6to4 */
 706         if (dev->priv_flags & IFF_ISATAP) {
 707                 struct neighbour *neigh = NULL;
 708                 bool do_tx_error = false;
 709
 710                 if (skb_dst(skb))
 711                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 712
 713                 if (neigh == NULL) {
 714                         net_dbg_ratelimited("sit: nexthop == NULL\n");
 715                         goto tx_error;
 716                 }
 717
 718                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 719                 addr_type = ipv6_addr_type(addr6);
 720
 721                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 722                      ipv6_addr_is_isatap(addr6))
 723                         dst = addr6->s6_addr32[3];
 724                 else
 725                         do_tx_error = true;
 726
 727                 neigh_release(neigh);
 728                 if (do_tx_error)
 729                         goto tx_error;
 730         }
 731
 732         if (!dst)
 733                 dst = try_6rd(&iph6->daddr, tunnel);
 734
 735         if (!dst) {
 736                 struct neighbour *neigh = NULL;
 737                 bool do_tx_error = false;
 738
 739                 if (skb_dst(skb))
 740                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 741
 742                 if (neigh == NULL) {
 743                         net_dbg_ratelimited("sit: nexthop == NULL\n");
 744                         goto tx_error;
 745                 }
 746
 747                 addr6 = (const struct in6_addr *)&neigh->primary_key;
 748                 addr_type = ipv6_addr_type(addr6);
 749
 750                 if (addr_type == IPV6_ADDR_ANY) {
 751                         addr6 = &ipv6_hdr(skb)->daddr;
 752                         addr_type = ipv6_addr_type(addr6);
 753                 }
 754
 755                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 756                         dst = addr6->s6_addr32[3];
 757                 else
 758                         do_tx_error = true;
 759
 760                 neigh_release(neigh);
 761                 if (do_tx_error)
 762                         goto tx_error;
 763         }
 764
 765         rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 766                                    dst, tiph->saddr,
 767                                    0, 0,
 768                                    IPPROTO_IPV6, RT_TOS(tos),
 769                                    tunnel->parms.link);
 770         if (IS_ERR(rt)) {
 771                 dev->stats.tx_carrier_errors++;
 772                 goto tx_error_icmp;
 773         }
 774         if (rt->rt_type != RTN_UNICAST) {
 775                 ip_rt_put(rt);
 776                 dev->stats.tx_carrier_errors++;
 777                 goto tx_error_icmp;
 778         }
 779         tdev = rt->dst.dev;
 780
 781         if (tdev == dev) {
 782                 ip_rt_put(rt);
 783                 dev->stats.collisions++;
 784                 goto tx_error;
 785         }
 786
 787         if (df) {
 788                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 789
 790                 if (mtu < 68) {
 791                         dev->stats.collisions++;
 792                         ip_rt_put(rt);
 793                         goto tx_error;
 794                 }
 795
 796                 if (mtu < IPV6_MIN_MTU) {
 797                         mtu = IPV6_MIN_MTU;
 798                         df = 0;
 799                 }
 800
 801                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 802                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 803
 804                 if (skb->len > mtu) {
 805                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 806                         ip_rt_put(rt);
 807                         goto tx_error;
 808                 }
 809         }
 810
 811         if (tunnel->err_count > 0) {
 812                 if (time_before(jiffies,
 813                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 814                         tunnel->err_count--;
 815                         dst_link_failure(skb);
 816                 } else
 817                         tunnel->err_count = 0;
 818         }
 819
 820         /*
 821          * Okay, now see if we can stuff it in the buffer as-is.
 822          */
 823         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 824
 825         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 826             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 827                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 828                 if (!new_skb) {
 829                         ip_rt_put(rt);
 830                         dev->stats.tx_dropped++;
 831                         dev_kfree_skb(skb);
 832                         return NETDEV_TX_OK;
 833                 }
 834                 if (skb->sk)
 835                         skb_set_owner_w(new_skb, skb->sk);
 836                 dev_kfree_skb(skb);
 837                 skb = new_skb;
 838                 iph6 = ipv6_hdr(skb);
 839         }
 840
 841         skb->transport_header = skb->network_header;
 842         skb_push(skb, sizeof(struct iphdr));
 843         skb_reset_network_header(skb);
 844         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 845         IPCB(skb)->flags = 0;
 846         skb_dst_drop(skb);
 847         skb_dst_set(skb, &rt->dst);
 848
 849         /*
 850          *      Push down and install the IPIP header.
 851          */
 852
 853         iph                     =       ip_hdr(skb);
 854         iph->version            =       4;
 855         iph->ihl                =       sizeof(struct iphdr)>>2;
 856         iph->frag_off           =       df;
 857         iph->protocol           =       IPPROTO_IPV6;
 858         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 859         iph->daddr              =       fl4.daddr;
 860         iph->saddr              =       fl4.saddr;
 861
 862         if ((iph->ttl = tiph->ttl) == 0)
 863                 iph->ttl        =       iph6->hop_limit;
 864
 865         nf_reset(skb);
 866         tstats = this_cpu_ptr(dev->tstats);
 867         __IPTUNNEL_XMIT(tstats, &dev->stats);
 868         return NETDEV_TX_OK;
 869
 870 tx_error_icmp:
 871         dst_link_failure(skb);
 872 tx_error:
 873         dev->stats.tx_errors++;
 874         dev_kfree_skb(skb);
 875         return NETDEV_TX_OK;
 876 }
 877
 878 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 879 {
 880         struct net_device *tdev = NULL;
 881         struct ip_tunnel *tunnel;
 882         const struct iphdr *iph;
 883         struct flowi4 fl4;
 884
 885         tunnel = netdev_priv(dev);
 886         iph = &tunnel->parms.iph;
 887
 888         if (iph->daddr) {
 889                 struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 890                                                           iph->daddr, iph->saddr,
 891                                                           0, 0,
 892                                                           IPPROTO_IPV6,
 893                                                           RT_TOS(iph->tos),
 894                                                           tunnel->parms.link);
 895
 896                 if (!IS_ERR(rt)) {
 897                         tdev = rt->dst.dev;
 898                         ip_rt_put(rt);
 899                 }
 900                 dev->flags |= IFF_POINTOPOINT;
 901         }
 902
 903         if (!tdev && tunnel->parms.link)
 904                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 905
 906         if (tdev) {
 907                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 908                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 909                 if (dev->mtu < IPV6_MIN_MTU)
 910                         dev->mtu = IPV6_MIN_MTU;
 911         }
 912         dev->iflink = tunnel->parms.link;
 913 }
 914
 915 static int
 916 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 917 {
 918         int err = 0;
 919         struct ip_tunnel_parm p;
 920         struct ip_tunnel_prl prl;
 921         struct ip_tunnel *t;
 922         struct net *net = dev_net(dev);
 923         struct sit_net *sitn = net_generic(net, sit_net_id);
 924 #ifdef CONFIG_IPV6_SIT_6RD
 925         struct ip_tunnel_6rd ip6rd;
 926 #endif
 927
 928         switch (cmd) {
 929         case SIOCGETTUNNEL:
 930 #ifdef CONFIG_IPV6_SIT_6RD
 931         case SIOCGET6RD:
 932 #endif
 933                 t = NULL;
 934                 if (dev == sitn->fb_tunnel_dev) {
 935                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 936                                 err = -EFAULT;
 937                                 break;
 938                         }
 939                         t = ipip6_tunnel_locate(net, &p, 0);
 940                 }
 941                 if (t == NULL)
 942                         t = netdev_priv(dev);
 943
 944                 err = -EFAULT;
 945                 if (cmd == SIOCGETTUNNEL) {
 946                         memcpy(&p, &t->parms, sizeof(p));
 947                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
 948                                          sizeof(p)))
 949                                 goto done;
 950 #ifdef CONFIG_IPV6_SIT_6RD
 951                 } else {
 952                         ip6rd.prefix = t->ip6rd.prefix;
 953                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
 954                         ip6rd.prefixlen = t->ip6rd.prefixlen;
 955                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
 956                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
 957                                          sizeof(ip6rd)))
 958                                 goto done;
 959 #endif
 960                 }
 961                 err = 0;
 962                 break;
 963
 964         case SIOCADDTUNNEL:
 965         case SIOCCHGTUNNEL:
 966                 err = -EPERM;
 967                 if (!capable(CAP_NET_ADMIN))
 968                         goto done;
 969
 970                 err = -EFAULT;
 971                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 972                         goto done;
 973
 974                 err = -EINVAL;
 975                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 976                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 977                         goto done;
 978                 if (p.iph.ttl)
 979                         p.iph.frag_off |= htons(IP_DF);
 980
 981                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 982
 983                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 984                         if (t != NULL) {
 985                                 if (t->dev != dev) {
 986                                         err = -EEXIST;
 987                                         break;
 988                                 }
 989                         } else {
 990                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 991                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 992                                         err = -EINVAL;
 993                                         break;
 994                                 }
 995                                 t = netdev_priv(dev);
 996                                 ipip6_tunnel_unlink(sitn, t);
 997                                 synchronize_net();
 998                                 t->parms.iph.saddr = p.iph.saddr;
 999                                 t->parms.iph.daddr = p.iph.daddr;
1000                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1001                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
1002                                 ipip6_tunnel_link(sitn, t);
1003                                 netdev_state_change(dev);
1004                         }
1005                 }
1006
1007                 if (t) {
1008                         err = 0;
1009                         if (cmd == SIOCCHGTUNNEL) {
1010                                 t->parms.iph.ttl = p.iph.ttl;
1011                                 t->parms.iph.tos = p.iph.tos;
1012                                 if (t->parms.link != p.link) {
1013                                         t->parms.link = p.link;
1014                                         ipip6_tunnel_bind_dev(dev);
1015                                         netdev_state_change(dev);
1016                                 }
1017                         }
1018                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1019                                 err = -EFAULT;
1020                 } else
1021                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1022                 break;
1023
1024         case SIOCDELTUNNEL:
1025                 err = -EPERM;
1026                 if (!capable(CAP_NET_ADMIN))
1027                         goto done;
1028
1029                 if (dev == sitn->fb_tunnel_dev) {
1030                         err = -EFAULT;
1031                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1032                                 goto done;
1033                         err = -ENOENT;
1034                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1035                                 goto done;
1036                         err = -EPERM;
1037                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1038                                 goto done;
1039                         dev = t->dev;
1040                 }
1041                 unregister_netdevice(dev);
1042                 err = 0;
1043                 break;
1044
1045         case SIOCGETPRL:
1046                 err = -EINVAL;
1047                 if (dev == sitn->fb_tunnel_dev)
1048                         goto done;
1049                 err = -ENOENT;
1050                 if (!(t = netdev_priv(dev)))
1051                         goto done;
1052                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1053                 break;
1054
1055         case SIOCADDPRL:
1056         case SIOCDELPRL:
1057         case SIOCCHGPRL:
1058                 err = -EPERM;
1059                 if (!capable(CAP_NET_ADMIN))
1060                         goto done;
1061                 err = -EINVAL;
1062                 if (dev == sitn->fb_tunnel_dev)
1063                         goto done;
1064                 err = -EFAULT;
1065                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1066                         goto done;
1067                 err = -ENOENT;
1068                 if (!(t = netdev_priv(dev)))
1069                         goto done;
1070
1071                 switch (cmd) {
1072                 case SIOCDELPRL:
1073                         err = ipip6_tunnel_del_prl(t, &prl);
1074                         break;
1075                 case SIOCADDPRL:
1076                 case SIOCCHGPRL:
1077                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1078                         break;
1079                 }
1080                 netdev_state_change(dev);
1081                 break;
1082
1083 #ifdef CONFIG_IPV6_SIT_6RD
1084         case SIOCADD6RD:
1085         case SIOCCHG6RD:
1086         case SIOCDEL6RD:
1087                 err = -EPERM;
1088                 if (!capable(CAP_NET_ADMIN))
1089                         goto done;
1090
1091                 err = -EFAULT;
1092                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1093                                    sizeof(ip6rd)))
1094                         goto done;
1095
1096                 t = netdev_priv(dev);
1097
1098                 if (cmd != SIOCDEL6RD) {
1099                         struct in6_addr prefix;
1100                         __be32 relay_prefix;
1101
1102                         err = -EINVAL;
1103                         if (ip6rd.relay_prefixlen > 32 ||
1104                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1105                                 goto done;
1106
1107                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1108                                          ip6rd.prefixlen);
1109                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1110                                 goto done;
1111                         if (ip6rd.relay_prefixlen)
1112                                 relay_prefix = ip6rd.relay_prefix &
1113                                                htonl(0xffffffffUL <<
1114                                                      (32 - ip6rd.relay_prefixlen));
1115                         else
1116                                 relay_prefix = 0;
1117                         if (relay_prefix != ip6rd.relay_prefix)
1118                                 goto done;
1119
1120                         t->ip6rd.prefix = prefix;
1121                         t->ip6rd.relay_prefix = relay_prefix;
1122                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1123                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1124                 } else
1125                         ipip6_tunnel_clone_6rd(dev, sitn);
1126
1127                 err = 0;
1128                 break;
1129 #endif
1130
1131         default:
1132                 err = -EINVAL;
1133         }
1134
1135 done:
1136         return err;
1137 }
1138
1139 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1140 {
1141         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1142                 return -EINVAL;
1143         dev->mtu = new_mtu;
1144         return 0;
1145 }
1146
1147 static const struct net_device_ops ipip6_netdev_ops = {
1148         .ndo_uninit     = ipip6_tunnel_uninit,
1149         .ndo_start_xmit = ipip6_tunnel_xmit,
1150         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1151         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1152         .ndo_get_stats64= ipip6_get_stats64,
1153 };
1154
1155 static void ipip6_dev_free(struct net_device *dev)
1156 {
1157         free_percpu(dev->tstats);
1158         free_netdev(dev);
1159 }
1160
1161 static void ipip6_tunnel_setup(struct net_device *dev)
1162 {
1163         dev->netdev_ops         = &ipip6_netdev_ops;
1164         dev->destructor         = ipip6_dev_free;
1165
1166         dev->type               = ARPHRD_SIT;
1167         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1168         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1169         dev->flags              = IFF_NOARP;
1170         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1171         dev->iflink             = 0;
1172         dev->addr_len           = 4;
1173         dev->features           |= NETIF_F_NETNS_LOCAL;
1174         dev->features           |= NETIF_F_LLTX;
1175 }
1176
1177 static int ipip6_tunnel_init(struct net_device *dev)
1178 {
1179         struct ip_tunnel *tunnel = netdev_priv(dev);
1180
1181         tunnel->dev = dev;
1182
1183         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1184         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1185
1186         ipip6_tunnel_bind_dev(dev);
1187         dev->tstats = alloc_percpu(struct pcpu_tstats);
1188         if (!dev->tstats)
1189                 return -ENOMEM;
1190
1191         return 0;
1192 }
1193
1194 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1195 {
1196         struct ip_tunnel *tunnel = netdev_priv(dev);
1197         struct iphdr *iph = &tunnel->parms.iph;
1198         struct net *net = dev_net(dev);
1199         struct sit_net *sitn = net_generic(net, sit_net_id);
1200
1201         tunnel->dev = dev;
1202         strcpy(tunnel->parms.name, dev->name);
1203
1204         iph->version            = 4;
1205         iph->protocol           = IPPROTO_IPV6;
1206         iph->ihl                = 5;
1207         iph->ttl                = 64;
1208
1209         dev->tstats = alloc_percpu(struct pcpu_tstats);
1210         if (!dev->tstats)
1211                 return -ENOMEM;
1212         dev_hold(dev);
1213         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1214         return 0;
1215 }
1216
1217 static struct xfrm_tunnel sit_handler __read_mostly = {
1218         .handler        =       ipip6_rcv,
1219         .err_handler    =       ipip6_err,
1220         .priority       =       1,
1221 };
1222
1223 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1224 {
1225         int prio;
1226
1227         for (prio = 1; prio < 4; prio++) {
1228                 int h;
1229                 for (h = 0; h < HASH_SIZE; h++) {
1230                         struct ip_tunnel *t;
1231
1232                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1233                         while (t != NULL) {
1234                                 unregister_netdevice_queue(t->dev, head);
1235                                 t = rtnl_dereference(t->next);
1236                         }
1237                 }
1238         }
1239 }
1240
1241 static int __net_init sit_init_net(struct net *net)
1242 {
1243         struct sit_net *sitn = net_generic(net, sit_net_id);
1244         struct ip_tunnel *t;
1245         int err;
1246
1247         sitn->tunnels[0] = sitn->tunnels_wc;
1248         sitn->tunnels[1] = sitn->tunnels_l;
1249         sitn->tunnels[2] = sitn->tunnels_r;
1250         sitn->tunnels[3] = sitn->tunnels_r_l;
1251
1252         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1253                                            ipip6_tunnel_setup);
1254         if (!sitn->fb_tunnel_dev) {
1255                 err = -ENOMEM;
1256                 goto err_alloc_dev;
1257         }
1258         dev_net_set(sitn->fb_tunnel_dev, net);
1259
1260         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1261         if (err)
1262                 goto err_dev_free;
1263
1264         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1265
1266         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1267                 goto err_reg_dev;
1268
1269         t = netdev_priv(sitn->fb_tunnel_dev);
1270
1271         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1272         return 0;
1273
1274 err_reg_dev:
1275         dev_put(sitn->fb_tunnel_dev);
1276 err_dev_free:
1277         ipip6_dev_free(sitn->fb_tunnel_dev);
1278 err_alloc_dev:
1279         return err;
1280 }
1281
1282 static void __net_exit sit_exit_net(struct net *net)
1283 {
1284         struct sit_net *sitn = net_generic(net, sit_net_id);
1285         LIST_HEAD(list);
1286
1287         rtnl_lock();
1288         sit_destroy_tunnels(sitn, &list);
1289         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1290         unregister_netdevice_many(&list);
1291         rtnl_unlock();
1292 }
1293
1294 static struct pernet_operations sit_net_ops = {
1295         .init = sit_init_net,
1296         .exit = sit_exit_net,
1297         .id   = &sit_net_id,
1298         .size = sizeof(struct sit_net),
1299 };
1300
1301 static void __exit sit_cleanup(void)
1302 {
1303         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1304
1305         unregister_pernet_device(&sit_net_ops);
1306         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1307 }
1308
1309 static int __init sit_init(void)
1310 {
1311         int err;
1312
1313         pr_info("IPv6 over IPv4 tunneling driver\n");
1314
1315         err = register_pernet_device(&sit_net_ops);
1316         if (err < 0)
1317                 return err;
1318         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1319         if (err < 0) {
1320                 unregister_pernet_device(&sit_net_ops);
1321                 pr_info("%s: can't add protocol\n", __func__);
1322         }
1323         return err;
1324 }
1325
1326 module_init(sit_init);
1327 module_exit(sit_cleanup);
1328 MODULE_LICENSE("GPL");
1329 MODULE_ALIAS_NETDEV("sit0");