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 #include <linux/module.h>
  21 #include <linux/capability.h>
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/socket.h>
  25 #include <linux/sockios.h>
  26 #include <linux/net.h>
  27 #include <linux/in6.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/icmp.h>
  31 #include <linux/slab.h>
  32 #include <asm/uaccess.h>
  33 #include <linux/init.h>
  34 #include <linux/netfilter_ipv4.h>
  35 #include <linux/if_ether.h>
  36
  37 #include <net/sock.h>
  38 #include <net/snmp.h>
  39
  40 #include <net/ipv6.h>
  41 #include <net/protocol.h>
  42 #include <net/transp_v6.h>
  43 #include <net/ip6_fib.h>
  44 #include <net/ip6_route.h>
  45 #include <net/ndisc.h>
  46 #include <net/addrconf.h>
  47 #include <net/ip.h>
  48 #include <net/udp.h>
  49 #include <net/icmp.h>
  50 #include <net/ipip.h>
  51 #include <net/inet_ecn.h>
  52 #include <net/xfrm.h>
  53 #include <net/dsfield.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 /*
  58    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  59
  60    For comments look at net/ipv4/ip_gre.c --ANK
  61  */
  62
  63 #define HASH_SIZE  16
  64 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  65
  66 static int ipip6_tunnel_init(struct net_device *dev);
  67 static void ipip6_tunnel_setup(struct net_device *dev);
  68 static void ipip6_dev_free(struct net_device *dev);
  69
  70 static int sit_net_id __read_mostly;
  71 struct sit_net {
  72         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  73         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  74         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  75         struct ip_tunnel __rcu *tunnels_wc[1];
  76         struct ip_tunnel __rcu **tunnels[4];
  77
  78         struct net_device *fb_tunnel_dev;
  79 };
  80
  81 /*
  82  * Locking : hash tables are protected by RCU and RTNL
  83  */
  84
  85 #define for_each_ip_tunnel_rcu(start) \
  86         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
  87
  88 /* often modified stats are per cpu, other are shared (netdev->stats) */
  89 struct pcpu_tstats {
  90         unsigned long   rx_packets;
  91         unsigned long   rx_bytes;
  92         unsigned long   tx_packets;
  93         unsigned long   tx_bytes;
  94 };
  95
  96 static struct net_device_stats *ipip6_get_stats(struct net_device *dev)
  97 {
  98         struct pcpu_tstats sum = { 0 };
  99         int i;
 100
 101         for_each_possible_cpu(i) {
 102                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 103
 104                 sum.rx_packets += tstats->rx_packets;
 105                 sum.rx_bytes   += tstats->rx_bytes;
 106                 sum.tx_packets += tstats->tx_packets;
 107                 sum.tx_bytes   += tstats->tx_bytes;
 108         }
 109         dev->stats.rx_packets = sum.rx_packets;
 110         dev->stats.rx_bytes   = sum.rx_bytes;
 111         dev->stats.tx_packets = sum.tx_packets;
 112         dev->stats.tx_bytes   = sum.tx_bytes;
 113         return &dev->stats;
 114 }
 115 /*
 116  * Must be invoked with rcu_read_lock
 117  */
 118 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
 119                 struct net_device *dev, __be32 remote, __be32 local)
 120 {
 121         unsigned int h0 = HASH(remote);
 122         unsigned int h1 = HASH(local);
 123         struct ip_tunnel *t;
 124         struct sit_net *sitn = net_generic(net, sit_net_id);
 125
 126         for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
 127                 if (local == t->parms.iph.saddr &&
 128                     remote == t->parms.iph.daddr &&
 129                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 130                     (t->dev->flags & IFF_UP))
 131                         return t;
 132         }
 133         for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
 134                 if (remote == t->parms.iph.daddr &&
 135                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 136                     (t->dev->flags & IFF_UP))
 137                         return t;
 138         }
 139         for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
 140                 if (local == t->parms.iph.saddr &&
 141                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 142                     (t->dev->flags & IFF_UP))
 143                         return t;
 144         }
 145         t = rcu_dereference(sitn->tunnels_wc[0]);
 146         if ((t != NULL) && (t->dev->flags & IFF_UP))
 147                 return t;
 148         return NULL;
 149 }
 150
 151 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 152                 struct ip_tunnel_parm *parms)
 153 {
 154         __be32 remote = parms->iph.daddr;
 155         __be32 local = parms->iph.saddr;
 156         unsigned int h = 0;
 157         int prio = 0;
 158
 159         if (remote) {
 160                 prio |= 2;
 161                 h ^= HASH(remote);
 162         }
 163         if (local) {
 164                 prio |= 1;
 165                 h ^= HASH(local);
 166         }
 167         return &sitn->tunnels[prio][h];
 168 }
 169
 170 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 171                 struct ip_tunnel *t)
 172 {
 173         return __ipip6_bucket(sitn, &t->parms);
 174 }
 175
 176 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 177 {
 178         struct ip_tunnel __rcu **tp;
 179         struct ip_tunnel *iter;
 180
 181         for (tp = ipip6_bucket(sitn, t);
 182              (iter = rtnl_dereference(*tp)) != NULL;
 183              tp = &iter->next) {
 184                 if (t == iter) {
 185                         rcu_assign_pointer(*tp, t->next);
 186                         break;
 187                 }
 188         }
 189 }
 190
 191 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 192 {
 193         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 194
 195         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 196         rcu_assign_pointer(*tp, t);
 197 }
 198
 199 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 200 {
 201 #ifdef CONFIG_IPV6_SIT_6RD
 202         struct ip_tunnel *t = netdev_priv(dev);
 203
 204         if (t->dev == sitn->fb_tunnel_dev) {
 205                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 206                 t->ip6rd.relay_prefix = 0;
 207                 t->ip6rd.prefixlen = 16;
 208                 t->ip6rd.relay_prefixlen = 0;
 209         } else {
 210                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 211                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 212         }
 213 #endif
 214 }
 215
 216 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 217                 struct ip_tunnel_parm *parms, int create)
 218 {
 219         __be32 remote = parms->iph.daddr;
 220         __be32 local = parms->iph.saddr;
 221         struct ip_tunnel *t, *nt;
 222         struct ip_tunnel __rcu **tp;
 223         struct net_device *dev;
 224         char name[IFNAMSIZ];
 225         struct sit_net *sitn = net_generic(net, sit_net_id);
 226
 227         for (tp = __ipip6_bucket(sitn, parms);
 228             (t = rtnl_dereference(*tp)) != NULL;
 229              tp = &t->next) {
 230                 if (local == t->parms.iph.saddr &&
 231                     remote == t->parms.iph.daddr &&
 232                     parms->link == t->parms.link) {
 233                         if (create)
 234                                 return NULL;
 235                         else
 236                                 return t;
 237                 }
 238         }
 239         if (!create)
 240                 goto failed;
 241
 242         if (parms->name[0])
 243                 strlcpy(name, parms->name, IFNAMSIZ);
 244         else
 245                 strcpy(name, "sit%d");
 246
 247         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 248         if (dev == NULL)
 249                 return NULL;
 250
 251         dev_net_set(dev, net);
 252
 253         nt = netdev_priv(dev);
 254
 255         nt->parms = *parms;
 256         if (ipip6_tunnel_init(dev) < 0)
 257                 goto failed_free;
 258         ipip6_tunnel_clone_6rd(dev, sitn);
 259
 260         if (parms->i_flags & SIT_ISATAP)
 261                 dev->priv_flags |= IFF_ISATAP;
 262
 263         if (register_netdevice(dev) < 0)
 264                 goto failed_free;
 265
 266         dev_hold(dev);
 267
 268         ipip6_tunnel_link(sitn, nt);
 269         return nt;
 270
 271 failed_free:
 272         ipip6_dev_free(dev);
 273 failed:
 274         return NULL;
 275 }
 276
 277 #define for_each_prl_rcu(start)                 \
 278         for (prl = rcu_dereference(start);      \
 279              prl;                               \
 280              prl = rcu_dereference(prl->next))
 281
 282 static struct ip_tunnel_prl_entry *
 283 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 284 {
 285         struct ip_tunnel_prl_entry *prl;
 286
 287         for_each_prl_rcu(t->prl)
 288                 if (prl->addr == addr)
 289                         break;
 290         return prl;
 291
 292 }
 293
 294 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 295                                 struct ip_tunnel_prl __user *a)
 296 {
 297         struct ip_tunnel_prl kprl, *kp;
 298         struct ip_tunnel_prl_entry *prl;
 299         unsigned int cmax, c = 0, ca, len;
 300         int ret = 0;
 301
 302         if (copy_from_user(&kprl, a, sizeof(kprl)))
 303                 return -EFAULT;
 304         cmax = kprl.datalen / sizeof(kprl);
 305         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 306                 cmax = 1;
 307
 308         /* For simple GET or for root users,
 309          * we try harder to allocate.
 310          */
 311         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 312                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 313                 NULL;
 314
 315         rcu_read_lock();
 316
 317         ca = t->prl_count < cmax ? t->prl_count : cmax;
 318
 319         if (!kp) {
 320                 /* We don't try hard to allocate much memory for
 321                  * non-root users.
 322                  * For root users, retry allocating enough memory for
 323                  * the answer.
 324                  */
 325                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 326                 if (!kp) {
 327                         ret = -ENOMEM;
 328                         goto out;
 329                 }
 330         }
 331
 332         c = 0;
 333         for_each_prl_rcu(t->prl) {
 334                 if (c >= cmax)
 335                         break;
 336                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 337                         continue;
 338                 kp[c].addr = prl->addr;
 339                 kp[c].flags = prl->flags;
 340                 c++;
 341                 if (kprl.addr != htonl(INADDR_ANY))
 342                         break;
 343         }
 344 out:
 345         rcu_read_unlock();
 346
 347         len = sizeof(*kp) * c;
 348         ret = 0;
 349         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 350                 ret = -EFAULT;
 351
 352         kfree(kp);
 353
 354         return ret;
 355 }
 356
 357 static int
 358 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 359 {
 360         struct ip_tunnel_prl_entry *p;
 361         int err = 0;
 362
 363         if (a->addr == htonl(INADDR_ANY))
 364                 return -EINVAL;
 365
 366         ASSERT_RTNL();
 367
 368         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 369                 if (p->addr == a->addr) {
 370                         if (chg) {
 371                                 p->flags = a->flags;
 372                                 goto out;
 373                         }
 374                         err = -EEXIST;
 375                         goto out;
 376                 }
 377         }
 378
 379         if (chg) {
 380                 err = -ENXIO;
 381                 goto out;
 382         }
 383
 384         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 385         if (!p) {
 386                 err = -ENOBUFS;
 387                 goto out;
 388         }
 389
 390         p->next = t->prl;
 391         p->addr = a->addr;
 392         p->flags = a->flags;
 393         t->prl_count++;
 394         rcu_assign_pointer(t->prl, p);
 395 out:
 396         return err;
 397 }
 398
 399 static void prl_list_destroy_rcu(struct rcu_head *head)
 400 {
 401         struct ip_tunnel_prl_entry *p, *n;
 402
 403         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 404         do {
 405                 n = rcu_dereference_protected(p->next, 1);
 406                 kfree(p);
 407                 p = n;
 408         } while (p);
 409 }
 410
 411 static int
 412 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 413 {
 414         struct ip_tunnel_prl_entry *x;
 415         struct ip_tunnel_prl_entry __rcu **p;
 416         int err = 0;
 417
 418         ASSERT_RTNL();
 419
 420         if (a && a->addr != htonl(INADDR_ANY)) {
 421                 for (p = &t->prl;
 422                      (x = rtnl_dereference(*p)) != NULL;
 423                      p = &x->next) {
 424                         if (x->addr == a->addr) {
 425                                 *p = x->next;
 426                                 kfree_rcu(x, rcu_head);
 427                                 t->prl_count--;
 428                                 goto out;
 429                         }
 430                 }
 431                 err = -ENXIO;
 432         } else {
 433                 x = rtnl_dereference(t->prl);
 434                 if (x) {
 435                         t->prl_count = 0;
 436                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 437                         t->prl = NULL;
 438                 }
 439         }
 440 out:
 441         return err;
 442 }
 443
 444 static int
 445 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 446 {
 447         struct ip_tunnel_prl_entry *p;
 448         int ok = 1;
 449
 450         rcu_read_lock();
 451         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 452         if (p) {
 453                 if (p->flags & PRL_DEFAULT)
 454                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 455                 else
 456                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 457         } else {
 458                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 459
 460                 if (ipv6_addr_is_isatap(addr6) &&
 461                     (addr6->s6_addr32[3] == iph->saddr) &&
 462                     ipv6_chk_prefix(addr6, t->dev))
 463                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 464                 else
 465                         ok = 0;
 466         }
 467         rcu_read_unlock();
 468         return ok;
 469 }
 470
 471 static void ipip6_tunnel_uninit(struct net_device *dev)
 472 {
 473         struct net *net = dev_net(dev);
 474         struct sit_net *sitn = net_generic(net, sit_net_id);
 475
 476         if (dev == sitn->fb_tunnel_dev) {
 477                 rcu_assign_pointer(sitn->tunnels_wc[0], NULL);
 478         } else {
 479                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 480                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 481         }
 482         dev_put(dev);
 483 }
 484
 485
 486 static int ipip6_err(struct sk_buff *skb, u32 info)
 487 {
 488
 489 /* All the routers (except for Linux) return only
 490    8 bytes of packet payload. It means, that precise relaying of
 491    ICMP in the real Internet is absolutely infeasible.
 492  */
 493         const struct iphdr *iph = (const struct iphdr *)skb->data;
 494         const int type = icmp_hdr(skb)->type;
 495         const int code = icmp_hdr(skb)->code;
 496         struct ip_tunnel *t;
 497         int err;
 498
 499         switch (type) {
 500         default:
 501         case ICMP_PARAMETERPROB:
 502                 return 0;
 503
 504         case ICMP_DEST_UNREACH:
 505                 switch (code) {
 506                 case ICMP_SR_FAILED:
 507                 case ICMP_PORT_UNREACH:
 508                         /* Impossible event. */
 509                         return 0;
 510                 case ICMP_FRAG_NEEDED:
 511                         /* Soft state for pmtu is maintained by IP core. */
 512                         return 0;
 513                 default:
 514                         /* All others are translated to HOST_UNREACH.
 515                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 516                            I believe they are just ether pollution. --ANK
 517                          */
 518                         break;
 519                 }
 520                 break;
 521         case ICMP_TIME_EXCEEDED:
 522                 if (code != ICMP_EXC_TTL)
 523                         return 0;
 524                 break;
 525         }
 526
 527         err = -ENOENT;
 528
 529         rcu_read_lock();
 530         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 531                                 skb->dev,
 532                                 iph->daddr,
 533                                 iph->saddr);
 534         if (t == NULL || t->parms.iph.daddr == 0)
 535                 goto out;
 536
 537         err = 0;
 538         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 539                 goto out;
 540
 541         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 542                 t->err_count++;
 543         else
 544                 t->err_count = 1;
 545         t->err_time = jiffies;
 546 out:
 547         rcu_read_unlock();
 548         return err;
 549 }
 550
 551 static inline void ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 552 {
 553         if (INET_ECN_is_ce(iph->tos))
 554                 IP6_ECN_set_ce(ipv6_hdr(skb));
 555 }
 556
 557 static int ipip6_rcv(struct sk_buff *skb)
 558 {
 559         const struct iphdr *iph;
 560         struct ip_tunnel *tunnel;
 561
 562         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 563                 goto out;
 564
 565         iph = ip_hdr(skb);
 566
 567         rcu_read_lock();
 568         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 569                                      iph->saddr, iph->daddr);
 570         if (tunnel != NULL) {
 571                 struct pcpu_tstats *tstats;
 572
 573                 secpath_reset(skb);
 574                 skb->mac_header = skb->network_header;
 575                 skb_reset_network_header(skb);
 576                 IPCB(skb)->flags = 0;
 577                 skb->protocol = htons(ETH_P_IPV6);
 578                 skb->pkt_type = PACKET_HOST;
 579
 580                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 581                     !isatap_chksrc(skb, iph, tunnel)) {
 582                         tunnel->dev->stats.rx_errors++;
 583                         rcu_read_unlock();
 584                         kfree_skb(skb);
 585                         return 0;
 586                 }
 587
 588                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 589                 tstats->rx_packets++;
 590                 tstats->rx_bytes += skb->len;
 591
 592                 __skb_tunnel_rx(skb, tunnel->dev);
 593
 594                 ipip6_ecn_decapsulate(iph, skb);
 595
 596                 netif_rx(skb);
 597
 598                 rcu_read_unlock();
 599                 return 0;
 600         }
 601
 602         /* no tunnel matched,  let upstream know, ipsec may handle it */
 603         rcu_read_unlock();
 604         return 1;
 605 out:
 606         kfree_skb(skb);
 607         return 0;
 608 }
 609
 610 /*
 611  * Returns the embedded IPv4 address if the IPv6 address
 612  * comes from 6rd / 6to4 (RFC 3056) addr space.
 613  */
 614 static inline
 615 __be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 616 {
 617         __be32 dst = 0;
 618
 619 #ifdef CONFIG_IPV6_SIT_6RD
 620         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 621                               tunnel->ip6rd.prefixlen)) {
 622                 unsigned int pbw0, pbi0;
 623                 int pbi1;
 624                 u32 d;
 625
 626                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
 627                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 628
 629                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 630                     tunnel->ip6rd.relay_prefixlen;
 631
 632                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 633                 if (pbi1 > 0)
 634                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 635                              (32 - pbi1);
 636
 637                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
 638         }
 639 #else
 640         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 641                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 642                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 643         }
 644 #endif
 645         return dst;
 646 }
 647
 648 /*
 649  *      This function assumes it is being called from dev_queue_xmit()
 650  *      and that skb is filled properly by that function.
 651  */
 652
 653 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 654                                      struct net_device *dev)
 655 {
 656         struct ip_tunnel *tunnel = netdev_priv(dev);
 657         struct pcpu_tstats *tstats;
 658         const struct iphdr  *tiph = &tunnel->parms.iph;
 659         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 660         u8     tos = tunnel->parms.iph.tos;
 661         __be16 df = tiph->frag_off;
 662         struct rtable *rt;                      /* Route to the other host */
 663         struct net_device *tdev;                /* Device to other host */
 664         struct iphdr  *iph;                     /* Our new IP header */
 665         unsigned int max_headroom;              /* The extra header space needed */
 666         __be32 dst = tiph->daddr;
 667         struct flowi4 fl4;
 668         int    mtu;
 669         const struct in6_addr *addr6;
 670         int addr_type;
 671
 672         if (skb->protocol != htons(ETH_P_IPV6))
 673                 goto tx_error;
 674
 675         /* ISATAP (RFC4214) - must come before 6to4 */
 676         if (dev->priv_flags & IFF_ISATAP) {
 677                 struct neighbour *neigh = NULL;
 678
 679                 if (skb_dst(skb))
 680                         neigh = dst_get_neighbour(skb_dst(skb));
 681
 682                 if (neigh == NULL) {
 683                         if (net_ratelimit())
 684                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 685                         goto tx_error;
 686                 }
 687
 688                 addr6 = (const struct in6_addr*)&neigh->primary_key;
 689                 addr_type = ipv6_addr_type(addr6);
 690
 691                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 692                      ipv6_addr_is_isatap(addr6))
 693                         dst = addr6->s6_addr32[3];
 694                 else
 695                         goto tx_error;
 696         }
 697
 698         if (!dst)
 699                 dst = try_6rd(&iph6->daddr, tunnel);
 700
 701         if (!dst) {
 702                 struct neighbour *neigh = NULL;
 703
 704                 if (skb_dst(skb))
 705                         neigh = dst_get_neighbour(skb_dst(skb));
 706
 707                 if (neigh == NULL) {
 708                         if (net_ratelimit())
 709                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 710                         goto tx_error;
 711                 }
 712
 713                 addr6 = (const struct in6_addr*)&neigh->primary_key;
 714                 addr_type = ipv6_addr_type(addr6);
 715
 716                 if (addr_type == IPV6_ADDR_ANY) {
 717                         addr6 = &ipv6_hdr(skb)->daddr;
 718                         addr_type = ipv6_addr_type(addr6);
 719                 }
 720
 721                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 722                         goto tx_error_icmp;
 723
 724                 dst = addr6->s6_addr32[3];
 725         }
 726
 727         rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 728                                    dst, tiph->saddr,
 729                                    0, 0,
 730                                    IPPROTO_IPV6, RT_TOS(tos),
 731                                    tunnel->parms.link);
 732         if (IS_ERR(rt)) {
 733                 dev->stats.tx_carrier_errors++;
 734                 goto tx_error_icmp;
 735         }
 736         if (rt->rt_type != RTN_UNICAST) {
 737                 ip_rt_put(rt);
 738                 dev->stats.tx_carrier_errors++;
 739                 goto tx_error_icmp;
 740         }
 741         tdev = rt->dst.dev;
 742
 743         if (tdev == dev) {
 744                 ip_rt_put(rt);
 745                 dev->stats.collisions++;
 746                 goto tx_error;
 747         }
 748
 749         if (df) {
 750                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 751
 752                 if (mtu < 68) {
 753                         dev->stats.collisions++;
 754                         ip_rt_put(rt);
 755                         goto tx_error;
 756                 }
 757
 758                 if (mtu < IPV6_MIN_MTU) {
 759                         mtu = IPV6_MIN_MTU;
 760                         df = 0;
 761                 }
 762
 763                 if (tunnel->parms.iph.daddr && skb_dst(skb))
 764                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 765
 766                 if (skb->len > mtu) {
 767                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 768                         ip_rt_put(rt);
 769                         goto tx_error;
 770                 }
 771         }
 772
 773         if (tunnel->err_count > 0) {
 774                 if (time_before(jiffies,
 775                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 776                         tunnel->err_count--;
 777                         dst_link_failure(skb);
 778                 } else
 779                         tunnel->err_count = 0;
 780         }
 781
 782         /*
 783          * Okay, now see if we can stuff it in the buffer as-is.
 784          */
 785         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 786
 787         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 788             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 789                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 790                 if (!new_skb) {
 791                         ip_rt_put(rt);
 792                         dev->stats.tx_dropped++;
 793                         dev_kfree_skb(skb);
 794                         return NETDEV_TX_OK;
 795                 }
 796                 if (skb->sk)
 797                         skb_set_owner_w(new_skb, skb->sk);
 798                 dev_kfree_skb(skb);
 799                 skb = new_skb;
 800                 iph6 = ipv6_hdr(skb);
 801         }
 802
 803         skb->transport_header = skb->network_header;
 804         skb_push(skb, sizeof(struct iphdr));
 805         skb_reset_network_header(skb);
 806         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 807         IPCB(skb)->flags = 0;
 808         skb_dst_drop(skb);
 809         skb_dst_set(skb, &rt->dst);
 810
 811         /*
 812          *      Push down and install the IPIP header.
 813          */
 814
 815         iph                     =       ip_hdr(skb);
 816         iph->version            =       4;
 817         iph->ihl                =       sizeof(struct iphdr)>>2;
 818         iph->frag_off           =       df;
 819         iph->protocol           =       IPPROTO_IPV6;
 820         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 821         iph->daddr              =       fl4.daddr;
 822         iph->saddr              =       fl4.saddr;
 823
 824         if ((iph->ttl = tiph->ttl) == 0)
 825                 iph->ttl        =       iph6->hop_limit;
 826
 827         nf_reset(skb);
 828         tstats = this_cpu_ptr(dev->tstats);
 829         __IPTUNNEL_XMIT(tstats, &dev->stats);
 830         return NETDEV_TX_OK;
 831
 832 tx_error_icmp:
 833         dst_link_failure(skb);
 834 tx_error:
 835         dev->stats.tx_errors++;
 836         dev_kfree_skb(skb);
 837         return NETDEV_TX_OK;
 838 }
 839
 840 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 841 {
 842         struct net_device *tdev = NULL;
 843         struct ip_tunnel *tunnel;
 844         const struct iphdr *iph;
 845         struct flowi4 fl4;
 846
 847         tunnel = netdev_priv(dev);
 848         iph = &tunnel->parms.iph;
 849
 850         if (iph->daddr) {
 851                 struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 852                                                           iph->daddr, iph->saddr,
 853                                                           0, 0,
 854                                                           IPPROTO_IPV6,
 855                                                           RT_TOS(iph->tos),
 856                                                           tunnel->parms.link);
 857
 858                 if (!IS_ERR(rt)) {
 859                         tdev = rt->dst.dev;
 860                         ip_rt_put(rt);
 861                 }
 862                 dev->flags |= IFF_POINTOPOINT;
 863         }
 864
 865         if (!tdev && tunnel->parms.link)
 866                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 867
 868         if (tdev) {
 869                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 870                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 871                 if (dev->mtu < IPV6_MIN_MTU)
 872                         dev->mtu = IPV6_MIN_MTU;
 873         }
 874         dev->iflink = tunnel->parms.link;
 875 }
 876
 877 static int
 878 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 879 {
 880         int err = 0;
 881         struct ip_tunnel_parm p;
 882         struct ip_tunnel_prl prl;
 883         struct ip_tunnel *t;
 884         struct net *net = dev_net(dev);
 885         struct sit_net *sitn = net_generic(net, sit_net_id);
 886 #ifdef CONFIG_IPV6_SIT_6RD
 887         struct ip_tunnel_6rd ip6rd;
 888 #endif
 889
 890         switch (cmd) {
 891         case SIOCGETTUNNEL:
 892 #ifdef CONFIG_IPV6_SIT_6RD
 893         case SIOCGET6RD:
 894 #endif
 895                 t = NULL;
 896                 if (dev == sitn->fb_tunnel_dev) {
 897                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 898                                 err = -EFAULT;
 899                                 break;
 900                         }
 901                         t = ipip6_tunnel_locate(net, &p, 0);
 902                 }
 903                 if (t == NULL)
 904                         t = netdev_priv(dev);
 905
 906                 err = -EFAULT;
 907                 if (cmd == SIOCGETTUNNEL) {
 908                         memcpy(&p, &t->parms, sizeof(p));
 909                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
 910                                          sizeof(p)))
 911                                 goto done;
 912 #ifdef CONFIG_IPV6_SIT_6RD
 913                 } else {
 914                         ipv6_addr_copy(&ip6rd.prefix, &t->ip6rd.prefix);
 915                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
 916                         ip6rd.prefixlen = t->ip6rd.prefixlen;
 917                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
 918                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
 919                                          sizeof(ip6rd)))
 920                                 goto done;
 921 #endif
 922                 }
 923                 err = 0;
 924                 break;
 925
 926         case SIOCADDTUNNEL:
 927         case SIOCCHGTUNNEL:
 928                 err = -EPERM;
 929                 if (!capable(CAP_NET_ADMIN))
 930                         goto done;
 931
 932                 err = -EFAULT;
 933                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 934                         goto done;
 935
 936                 err = -EINVAL;
 937                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 938                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 939                         goto done;
 940                 if (p.iph.ttl)
 941                         p.iph.frag_off |= htons(IP_DF);
 942
 943                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 944
 945                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 946                         if (t != NULL) {
 947                                 if (t->dev != dev) {
 948                                         err = -EEXIST;
 949                                         break;
 950                                 }
 951                         } else {
 952                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 953                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 954                                         err = -EINVAL;
 955                                         break;
 956                                 }
 957                                 t = netdev_priv(dev);
 958                                 ipip6_tunnel_unlink(sitn, t);
 959                                 synchronize_net();
 960                                 t->parms.iph.saddr = p.iph.saddr;
 961                                 t->parms.iph.daddr = p.iph.daddr;
 962                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 963                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 964                                 ipip6_tunnel_link(sitn, t);
 965                                 netdev_state_change(dev);
 966                         }
 967                 }
 968
 969                 if (t) {
 970                         err = 0;
 971                         if (cmd == SIOCCHGTUNNEL) {
 972                                 t->parms.iph.ttl = p.iph.ttl;
 973                                 t->parms.iph.tos = p.iph.tos;
 974                                 if (t->parms.link != p.link) {
 975                                         t->parms.link = p.link;
 976                                         ipip6_tunnel_bind_dev(dev);
 977                                         netdev_state_change(dev);
 978                                 }
 979                         }
 980                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 981                                 err = -EFAULT;
 982                 } else
 983                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 984                 break;
 985
 986         case SIOCDELTUNNEL:
 987                 err = -EPERM;
 988                 if (!capable(CAP_NET_ADMIN))
 989                         goto done;
 990
 991                 if (dev == sitn->fb_tunnel_dev) {
 992                         err = -EFAULT;
 993                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 994                                 goto done;
 995                         err = -ENOENT;
 996                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 997                                 goto done;
 998                         err = -EPERM;
 999                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1000                                 goto done;
1001                         dev = t->dev;
1002                 }
1003                 unregister_netdevice(dev);
1004                 err = 0;
1005                 break;
1006
1007         case SIOCGETPRL:
1008                 err = -EINVAL;
1009                 if (dev == sitn->fb_tunnel_dev)
1010                         goto done;
1011                 err = -ENOENT;
1012                 if (!(t = netdev_priv(dev)))
1013                         goto done;
1014                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1015                 break;
1016
1017         case SIOCADDPRL:
1018         case SIOCDELPRL:
1019         case SIOCCHGPRL:
1020                 err = -EPERM;
1021                 if (!capable(CAP_NET_ADMIN))
1022                         goto done;
1023                 err = -EINVAL;
1024                 if (dev == sitn->fb_tunnel_dev)
1025                         goto done;
1026                 err = -EFAULT;
1027                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1028                         goto done;
1029                 err = -ENOENT;
1030                 if (!(t = netdev_priv(dev)))
1031                         goto done;
1032
1033                 switch (cmd) {
1034                 case SIOCDELPRL:
1035                         err = ipip6_tunnel_del_prl(t, &prl);
1036                         break;
1037                 case SIOCADDPRL:
1038                 case SIOCCHGPRL:
1039                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1040                         break;
1041                 }
1042                 netdev_state_change(dev);
1043                 break;
1044
1045 #ifdef CONFIG_IPV6_SIT_6RD
1046         case SIOCADD6RD:
1047         case SIOCCHG6RD:
1048         case SIOCDEL6RD:
1049                 err = -EPERM;
1050                 if (!capable(CAP_NET_ADMIN))
1051                         goto done;
1052
1053                 err = -EFAULT;
1054                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1055                                    sizeof(ip6rd)))
1056                         goto done;
1057
1058                 t = netdev_priv(dev);
1059
1060                 if (cmd != SIOCDEL6RD) {
1061                         struct in6_addr prefix;
1062                         __be32 relay_prefix;
1063
1064                         err = -EINVAL;
1065                         if (ip6rd.relay_prefixlen > 32 ||
1066                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1067                                 goto done;
1068
1069                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1070                                          ip6rd.prefixlen);
1071                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1072                                 goto done;
1073                         if (ip6rd.relay_prefixlen)
1074                                 relay_prefix = ip6rd.relay_prefix &
1075                                                htonl(0xffffffffUL <<
1076                                                      (32 - ip6rd.relay_prefixlen));
1077                         else
1078                                 relay_prefix = 0;
1079                         if (relay_prefix != ip6rd.relay_prefix)
1080                                 goto done;
1081
1082                         ipv6_addr_copy(&t->ip6rd.prefix, &prefix);
1083                         t->ip6rd.relay_prefix = relay_prefix;
1084                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1085                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1086                 } else
1087                         ipip6_tunnel_clone_6rd(dev, sitn);
1088
1089                 err = 0;
1090                 break;
1091 #endif
1092
1093         default:
1094                 err = -EINVAL;
1095         }
1096
1097 done:
1098         return err;
1099 }
1100
1101 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1102 {
1103         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1104                 return -EINVAL;
1105         dev->mtu = new_mtu;
1106         return 0;
1107 }
1108
1109 static const struct net_device_ops ipip6_netdev_ops = {
1110         .ndo_uninit     = ipip6_tunnel_uninit,
1111         .ndo_start_xmit = ipip6_tunnel_xmit,
1112         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1113         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1114         .ndo_get_stats  = ipip6_get_stats,
1115 };
1116
1117 static void ipip6_dev_free(struct net_device *dev)
1118 {
1119         free_percpu(dev->tstats);
1120         free_netdev(dev);
1121 }
1122
1123 static void ipip6_tunnel_setup(struct net_device *dev)
1124 {
1125         dev->netdev_ops         = &ipip6_netdev_ops;
1126         dev->destructor         = ipip6_dev_free;
1127
1128         dev->type               = ARPHRD_SIT;
1129         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1130         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1131         dev->flags              = IFF_NOARP;
1132         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1133         dev->iflink             = 0;
1134         dev->addr_len           = 4;
1135         dev->features           |= NETIF_F_NETNS_LOCAL;
1136         dev->features           |= NETIF_F_LLTX;
1137 }
1138
1139 static int ipip6_tunnel_init(struct net_device *dev)
1140 {
1141         struct ip_tunnel *tunnel = netdev_priv(dev);
1142
1143         tunnel->dev = dev;
1144         strcpy(tunnel->parms.name, dev->name);
1145
1146         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1147         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1148
1149         ipip6_tunnel_bind_dev(dev);
1150         dev->tstats = alloc_percpu(struct pcpu_tstats);
1151         if (!dev->tstats)
1152                 return -ENOMEM;
1153
1154         return 0;
1155 }
1156
1157 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1158 {
1159         struct ip_tunnel *tunnel = netdev_priv(dev);
1160         struct iphdr *iph = &tunnel->parms.iph;
1161         struct net *net = dev_net(dev);
1162         struct sit_net *sitn = net_generic(net, sit_net_id);
1163
1164         tunnel->dev = dev;
1165         strcpy(tunnel->parms.name, dev->name);
1166
1167         iph->version            = 4;
1168         iph->protocol           = IPPROTO_IPV6;
1169         iph->ihl                = 5;
1170         iph->ttl                = 64;
1171
1172         dev->tstats = alloc_percpu(struct pcpu_tstats);
1173         if (!dev->tstats)
1174                 return -ENOMEM;
1175         dev_hold(dev);
1176         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1177         return 0;
1178 }
1179
1180 static struct xfrm_tunnel sit_handler __read_mostly = {
1181         .handler        =       ipip6_rcv,
1182         .err_handler    =       ipip6_err,
1183         .priority       =       1,
1184 };
1185
1186 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1187 {
1188         int prio;
1189
1190         for (prio = 1; prio < 4; prio++) {
1191                 int h;
1192                 for (h = 0; h < HASH_SIZE; h++) {
1193                         struct ip_tunnel *t;
1194
1195                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1196                         while (t != NULL) {
1197                                 unregister_netdevice_queue(t->dev, head);
1198                                 t = rtnl_dereference(t->next);
1199                         }
1200                 }
1201         }
1202 }
1203
1204 static int __net_init sit_init_net(struct net *net)
1205 {
1206         struct sit_net *sitn = net_generic(net, sit_net_id);
1207         int err;
1208
1209         sitn->tunnels[0] = sitn->tunnels_wc;
1210         sitn->tunnels[1] = sitn->tunnels_l;
1211         sitn->tunnels[2] = sitn->tunnels_r;
1212         sitn->tunnels[3] = sitn->tunnels_r_l;
1213
1214         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1215                                            ipip6_tunnel_setup);
1216         if (!sitn->fb_tunnel_dev) {
1217                 err = -ENOMEM;
1218                 goto err_alloc_dev;
1219         }
1220         dev_net_set(sitn->fb_tunnel_dev, net);
1221
1222         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1223         if (err)
1224                 goto err_dev_free;
1225
1226         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1227
1228         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1229                 goto err_reg_dev;
1230
1231         return 0;
1232
1233 err_reg_dev:
1234         dev_put(sitn->fb_tunnel_dev);
1235 err_dev_free:
1236         ipip6_dev_free(sitn->fb_tunnel_dev);
1237 err_alloc_dev:
1238         return err;
1239 }
1240
1241 static void __net_exit sit_exit_net(struct net *net)
1242 {
1243         struct sit_net *sitn = net_generic(net, sit_net_id);
1244         LIST_HEAD(list);
1245
1246         rtnl_lock();
1247         sit_destroy_tunnels(sitn, &list);
1248         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1249         unregister_netdevice_many(&list);
1250         rtnl_unlock();
1251 }
1252
1253 static struct pernet_operations sit_net_ops = {
1254         .init = sit_init_net,
1255         .exit = sit_exit_net,
1256         .id   = &sit_net_id,
1257         .size = sizeof(struct sit_net),
1258 };
1259
1260 static void __exit sit_cleanup(void)
1261 {
1262         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1263
1264         unregister_pernet_device(&sit_net_ops);
1265         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1266 }
1267
1268 static int __init sit_init(void)
1269 {
1270         int err;
1271
1272         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1273
1274         err = register_pernet_device(&sit_net_ops);
1275         if (err < 0)
1276                 return err;
1277         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1278         if (err < 0) {
1279                 unregister_pernet_device(&sit_net_ops);
1280                 printk(KERN_INFO "sit init: Can't add protocol\n");
1281         }
1282         return err;
1283 }
1284
1285 module_init(sit_init);
1286 module_exit(sit_cleanup);
1287 MODULE_LICENSE("GPL");
1288 MODULE_ALIAS_NETDEV("sit0");