git.oblomov.eu Git - linux-2.6/blob - 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  * Sascha Hlusiak <mail@saschahlusiak.de>:      stateless autoconf for isatap
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/capability.h>
  23 #include <linux/errno.h>
  24 #include <linux/types.h>
  25 #include <linux/socket.h>
  26 #include <linux/sockios.h>
  27 #include <linux/net.h>
  28 #include <linux/in6.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/icmp.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 void ipip6_fb_tunnel_init(struct net_device *dev);
  67 static void ipip6_tunnel_init(struct net_device *dev);
  68 static void ipip6_tunnel_setup(struct net_device *dev);
  69
  70 static int sit_net_id;
  71 struct sit_net {
  72         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  73         struct ip_tunnel *tunnels_r[HASH_SIZE];
  74         struct ip_tunnel *tunnels_l[HASH_SIZE];
  75         struct ip_tunnel *tunnels_wc[1];
  76         struct ip_tunnel **tunnels[4];
  77
  78         struct net_device *fb_tunnel_dev;
  79 };
  80
  81 static DEFINE_RWLOCK(ipip6_lock);
  82
  83 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
  84                 struct net_device *dev, __be32 remote, __be32 local)
  85 {
  86         unsigned h0 = HASH(remote);
  87         unsigned h1 = HASH(local);
  88         struct ip_tunnel *t;
  89         struct sit_net *sitn = net_generic(net, sit_net_id);
  90
  91         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
  92                 if (local == t->parms.iph.saddr &&
  93                     remote == t->parms.iph.daddr &&
  94                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
  95                     (t->dev->flags & IFF_UP))
  96                         return t;
  97         }
  98         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
  99                 if (remote == t->parms.iph.daddr &&
 100                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 101                     (t->dev->flags & IFF_UP))
 102                         return t;
 103         }
 104         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
 105                 if (local == t->parms.iph.saddr &&
 106                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 107                     (t->dev->flags & IFF_UP))
 108                         return t;
 109         }
 110         t = sitn->tunnels_wc[0];
 111         if ((t != NULL) && (t->dev->flags & IFF_UP))
 112                 return t;
 113         return NULL;
 114 }
 115
 116 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
 117                 struct ip_tunnel_parm *parms)
 118 {
 119         __be32 remote = parms->iph.daddr;
 120         __be32 local = parms->iph.saddr;
 121         unsigned h = 0;
 122         int prio = 0;
 123
 124         if (remote) {
 125                 prio |= 2;
 126                 h ^= HASH(remote);
 127         }
 128         if (local) {
 129                 prio |= 1;
 130                 h ^= HASH(local);
 131         }
 132         return &sitn->tunnels[prio][h];
 133 }
 134
 135 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
 136                 struct ip_tunnel *t)
 137 {
 138         return __ipip6_bucket(sitn, &t->parms);
 139 }
 140
 141 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 142 {
 143         struct ip_tunnel **tp;
 144
 145         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
 146                 if (t == *tp) {
 147                         write_lock_bh(&ipip6_lock);
 148                         *tp = t->next;
 149                         write_unlock_bh(&ipip6_lock);
 150                         break;
 151                 }
 152         }
 153 }
 154
 155 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 156 {
 157         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 158
 159         t->next = *tp;
 160         write_lock_bh(&ipip6_lock);
 161         *tp = t;
 162         write_unlock_bh(&ipip6_lock);
 163 }
 164
 165 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 166                 struct ip_tunnel_parm *parms, int create)
 167 {
 168         __be32 remote = parms->iph.daddr;
 169         __be32 local = parms->iph.saddr;
 170         struct ip_tunnel *t, **tp, *nt;
 171         struct net_device *dev;
 172         char name[IFNAMSIZ];
 173         struct sit_net *sitn = net_generic(net, sit_net_id);
 174
 175         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
 176                 if (local == t->parms.iph.saddr &&
 177                     remote == t->parms.iph.daddr &&
 178                     parms->link == t->parms.link) {
 179                         if (create)
 180                                 return NULL;
 181                         else
 182                                 return t;
 183                 }
 184         }
 185         if (!create)
 186                 goto failed;
 187
 188         if (parms->name[0])
 189                 strlcpy(name, parms->name, IFNAMSIZ);
 190         else
 191                 sprintf(name, "sit%%d");
 192
 193         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 194         if (dev == NULL)
 195                 return NULL;
 196
 197         dev_net_set(dev, net);
 198
 199         if (strchr(name, '%')) {
 200                 if (dev_alloc_name(dev, name) < 0)
 201                         goto failed_free;
 202         }
 203
 204         nt = netdev_priv(dev);
 205
 206         nt->parms = *parms;
 207         ipip6_tunnel_init(dev);
 208
 209         if (parms->i_flags & SIT_ISATAP)
 210                 dev->priv_flags |= IFF_ISATAP;
 211
 212         if (register_netdevice(dev) < 0)
 213                 goto failed_free;
 214
 215         dev_hold(dev);
 216
 217         ipip6_tunnel_link(sitn, nt);
 218         return nt;
 219
 220 failed_free:
 221         free_netdev(dev);
 222 failed:
 223         return NULL;
 224 }
 225
 226 static void ipip6_tunnel_rs_timer(unsigned long data)
 227 {
 228         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *) data;
 229         struct inet6_dev *ifp;
 230         struct inet6_ifaddr *addr;
 231
 232         spin_lock(&p->lock);
 233         ifp = __in6_dev_get(p->tunnel->dev);
 234
 235         read_lock_bh(&ifp->lock);
 236         for (addr = ifp->addr_list; addr; addr = addr->if_next) {
 237                 struct in6_addr rtr;
 238
 239                 if (!(ipv6_addr_type(&addr->addr) & IPV6_ADDR_LINKLOCAL))
 240                         continue;
 241
 242                 /* Send RS to guessed linklocal address of router
 243                  *
 244                  * Better: send to ff02::2 encapsuled in unicast directly
 245                  * to router-v4 instead of guessing the v6 address.
 246                  *
 247                  * Cisco/Windows seem to not set the u/l bit correctly,
 248                  * so we won't guess right.
 249                  */
 250                 ipv6_addr_set(&rtr,  htonl(0xFE800000), 0, 0, 0);
 251                 if (!__ipv6_isatap_ifid(rtr.s6_addr + 8,
 252                                         p->addr)) {
 253                         ndisc_send_rs(p->tunnel->dev, &addr->addr, &rtr);
 254                 }
 255         }
 256         read_unlock_bh(&ifp->lock);
 257
 258         mod_timer(&p->rs_timer, jiffies + HZ * p->rs_delay);
 259         spin_unlock(&p->lock);
 260
 261         return;
 262 }
 263
 264 static struct ip_tunnel_prl_entry *
 265 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 266 {
 267         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
 268
 269         for (p = t->prl; p; p = p->next)
 270                 if (p->addr == addr)
 271                         break;
 272         return p;
 273
 274 }
 275
 276 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 277                                 struct ip_tunnel_prl __user *a)
 278 {
 279         struct ip_tunnel_prl kprl, *kp;
 280         struct ip_tunnel_prl_entry *prl;
 281         unsigned int cmax, c = 0, ca, len;
 282         int ret = 0;
 283
 284         if (copy_from_user(&kprl, a, sizeof(kprl)))
 285                 return -EFAULT;
 286         cmax = kprl.datalen / sizeof(kprl);
 287         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 288                 cmax = 1;
 289
 290         /* For simple GET or for root users,
 291          * we try harder to allocate.
 292          */
 293         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 294                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 295                 NULL;
 296
 297         read_lock(&ipip6_lock);
 298
 299         ca = t->prl_count < cmax ? t->prl_count : cmax;
 300
 301         if (!kp) {
 302                 /* We don't try hard to allocate much memory for
 303                  * non-root users.
 304                  * For root users, retry allocating enough memory for
 305                  * the answer.
 306                  */
 307                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 308                 if (!kp) {
 309                         ret = -ENOMEM;
 310                         goto out;
 311                 }
 312         }
 313
 314         c = 0;
 315         for (prl = t->prl; prl; prl = prl->next) {
 316                 if (c > cmax)
 317                         break;
 318                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 319                         continue;
 320                 kp[c].addr = prl->addr;
 321                 kp[c].flags = prl->flags;
 322                 kp[c].rs_delay = prl->rs_delay;
 323                 c++;
 324                 if (kprl.addr != htonl(INADDR_ANY))
 325                         break;
 326         }
 327 out:
 328         read_unlock(&ipip6_lock);
 329
 330         len = sizeof(*kp) * c;
 331         ret = 0;
 332         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 333                 ret = -EFAULT;
 334
 335         kfree(kp);
 336
 337         return ret;
 338 }
 339
 340 static int
 341 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 342 {
 343         struct ip_tunnel_prl_entry *p;
 344         int err = 0;
 345
 346         if (a->addr == htonl(INADDR_ANY))
 347                 return -EINVAL;
 348
 349         write_lock(&ipip6_lock);
 350
 351         for (p = t->prl; p; p = p->next) {
 352                 if (p->addr == a->addr) {
 353                         if (chg)
 354                                 goto update;
 355                         err = -EEXIST;
 356                         goto out;
 357                 }
 358         }
 359
 360         if (chg) {
 361                 err = -ENXIO;
 362                 goto out;
 363         }
 364
 365         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 366         if (!p) {
 367                 err = -ENOBUFS;
 368                 goto out;
 369         }
 370
 371         p->next = t->prl;
 372         p->tunnel = t;
 373         t->prl = p;
 374         t->prl_count++;
 375
 376         spin_lock_init(&p->lock);
 377         setup_timer(&p->rs_timer, ipip6_tunnel_rs_timer, (unsigned long) p);
 378 update:
 379         p->addr = a->addr;
 380         p->flags = a->flags;
 381         p->rs_delay = a->rs_delay;
 382         if (p->rs_delay == 0)
 383                 p->rs_delay = IPTUNNEL_RS_DEFAULT_DELAY;
 384         spin_lock(&p->lock);
 385         del_timer(&p->rs_timer);
 386         if (p->flags & PRL_DEFAULT)
 387                 mod_timer(&p->rs_timer, jiffies + 1);
 388         spin_unlock(&p->lock);
 389 out:
 390         write_unlock(&ipip6_lock);
 391         return err;
 392 }
 393
 394 static int
 395 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 396 {
 397         struct ip_tunnel_prl_entry *x, **p;
 398         int err = 0;
 399
 400         write_lock(&ipip6_lock);
 401
 402         if (a && a->addr != htonl(INADDR_ANY)) {
 403                 for (p = &t->prl; *p; p = &(*p)->next) {
 404                         if ((*p)->addr == a->addr) {
 405                                 x = *p;
 406                                 *p = x->next;
 407                                 spin_lock(&x->lock);
 408                                 del_timer(&x->rs_timer);
 409                                 spin_unlock(&x->lock);
 410                                 kfree(x);
 411                                 t->prl_count--;
 412                                 goto out;
 413                         }
 414                 }
 415                 err = -ENXIO;
 416         } else {
 417                 while (t->prl) {
 418                         x = t->prl;
 419                         t->prl = t->prl->next;
 420                         spin_lock(&x->lock);
 421                         del_timer(&x->rs_timer);
 422                         spin_unlock(&x->lock);
 423                         kfree(x);
 424                         t->prl_count--;
 425                 }
 426         }
 427 out:
 428         write_unlock(&ipip6_lock);
 429         return err;
 430 }
 431
 432 static int
 433 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 434 {
 435         struct ip_tunnel_prl_entry *p;
 436         int ok = 1;
 437
 438         read_lock(&ipip6_lock);
 439         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 440         if (p) {
 441                 if (p->flags & PRL_DEFAULT)
 442                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 443                 else
 444                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 445         } else {
 446                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 447                 if (ipv6_addr_is_isatap(addr6) &&
 448                     (addr6->s6_addr32[3] == iph->saddr) &&
 449                     ipv6_chk_prefix(addr6, t->dev))
 450                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 451                 else
 452                         ok = 0;
 453         }
 454         read_unlock(&ipip6_lock);
 455         return ok;
 456 }
 457
 458 static void ipip6_tunnel_uninit(struct net_device *dev)
 459 {
 460         struct net *net = dev_net(dev);
 461         struct sit_net *sitn = net_generic(net, sit_net_id);
 462
 463         if (dev == sitn->fb_tunnel_dev) {
 464                 write_lock_bh(&ipip6_lock);
 465                 sitn->tunnels_wc[0] = NULL;
 466                 write_unlock_bh(&ipip6_lock);
 467                 dev_put(dev);
 468         } else {
 469                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 470                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 471                 dev_put(dev);
 472         }
 473 }
 474
 475
 476 static int ipip6_err(struct sk_buff *skb, u32 info)
 477 {
 478
 479 /* All the routers (except for Linux) return only
 480    8 bytes of packet payload. It means, that precise relaying of
 481    ICMP in the real Internet is absolutely infeasible.
 482  */
 483         struct iphdr *iph = (struct iphdr*)skb->data;
 484         const int type = icmp_hdr(skb)->type;
 485         const int code = icmp_hdr(skb)->code;
 486         struct ip_tunnel *t;
 487         int err;
 488
 489         switch (type) {
 490         default:
 491         case ICMP_PARAMETERPROB:
 492                 return 0;
 493
 494         case ICMP_DEST_UNREACH:
 495                 switch (code) {
 496                 case ICMP_SR_FAILED:
 497                 case ICMP_PORT_UNREACH:
 498                         /* Impossible event. */
 499                         return 0;
 500                 case ICMP_FRAG_NEEDED:
 501                         /* Soft state for pmtu is maintained by IP core. */
 502                         return 0;
 503                 default:
 504                         /* All others are translated to HOST_UNREACH.
 505                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 506                            I believe they are just ether pollution. --ANK
 507                          */
 508                         break;
 509                 }
 510                 break;
 511         case ICMP_TIME_EXCEEDED:
 512                 if (code != ICMP_EXC_TTL)
 513                         return 0;
 514                 break;
 515         }
 516
 517         err = -ENOENT;
 518
 519         read_lock(&ipip6_lock);
 520         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 521                                 skb->dev,
 522                                 iph->daddr,
 523                                 iph->saddr);
 524         if (t == NULL || t->parms.iph.daddr == 0)
 525                 goto out;
 526
 527         err = 0;
 528         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 529                 goto out;
 530
 531         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 532                 t->err_count++;
 533         else
 534                 t->err_count = 1;
 535         t->err_time = jiffies;
 536 out:
 537         read_unlock(&ipip6_lock);
 538         return err;
 539 }
 540
 541 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 542 {
 543         if (INET_ECN_is_ce(iph->tos))
 544                 IP6_ECN_set_ce(ipv6_hdr(skb));
 545 }
 546
 547 static int ipip6_rcv(struct sk_buff *skb)
 548 {
 549         struct iphdr *iph;
 550         struct ip_tunnel *tunnel;
 551
 552         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 553                 goto out;
 554
 555         iph = ip_hdr(skb);
 556
 557         read_lock(&ipip6_lock);
 558         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 559                                      iph->saddr, iph->daddr);
 560         if (tunnel != NULL) {
 561                 secpath_reset(skb);
 562                 skb->mac_header = skb->network_header;
 563                 skb_reset_network_header(skb);
 564                 IPCB(skb)->flags = 0;
 565                 skb->protocol = htons(ETH_P_IPV6);
 566                 skb->pkt_type = PACKET_HOST;
 567
 568                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 569                     !isatap_chksrc(skb, iph, tunnel)) {
 570                         tunnel->dev->stats.rx_errors++;
 571                         read_unlock(&ipip6_lock);
 572                         kfree_skb(skb);
 573                         return 0;
 574                 }
 575                 tunnel->dev->stats.rx_packets++;
 576                 tunnel->dev->stats.rx_bytes += skb->len;
 577                 skb->dev = tunnel->dev;
 578                 skb_dst_drop(skb);
 579                 nf_reset(skb);
 580                 ipip6_ecn_decapsulate(iph, skb);
 581                 netif_rx(skb);
 582                 read_unlock(&ipip6_lock);
 583                 return 0;
 584         }
 585
 586         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 587         read_unlock(&ipip6_lock);
 588 out:
 589         kfree_skb(skb);
 590         return 0;
 591 }
 592
 593 /* Returns the embedded IPv4 address if the IPv6 address
 594    comes from 6to4 (RFC 3056) addr space */
 595
 596 static inline __be32 try_6to4(struct in6_addr *v6dst)
 597 {
 598         __be32 dst = 0;
 599
 600         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 601                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 602                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 603         }
 604         return dst;
 605 }
 606
 607 /*
 608  *      This function assumes it is being called from dev_queue_xmit()
 609  *      and that skb is filled properly by that function.
 610  */
 611
 612 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 613 {
 614         struct ip_tunnel *tunnel = netdev_priv(dev);
 615         struct net_device_stats *stats = &tunnel->dev->stats;
 616         struct iphdr  *tiph = &tunnel->parms.iph;
 617         struct ipv6hdr *iph6 = ipv6_hdr(skb);
 618         u8     tos = tunnel->parms.iph.tos;
 619         struct rtable *rt;                      /* Route to the other host */
 620         struct net_device *tdev;                        /* Device to other host */
 621         struct iphdr  *iph;                     /* Our new IP header */
 622         unsigned int max_headroom;              /* The extra header space needed */
 623         __be32 dst = tiph->daddr;
 624         int    mtu;
 625         struct in6_addr *addr6;
 626         int addr_type;
 627
 628         if (tunnel->recursion++) {
 629                 stats->collisions++;
 630                 goto tx_error;
 631         }
 632
 633         if (skb->protocol != htons(ETH_P_IPV6))
 634                 goto tx_error;
 635
 636         /* ISATAP (RFC4214) - must come before 6to4 */
 637         if (dev->priv_flags & IFF_ISATAP) {
 638                 struct neighbour *neigh = NULL;
 639
 640                 if (skb_dst(skb))
 641                         neigh = skb_dst(skb)->neighbour;
 642
 643                 if (neigh == NULL) {
 644                         if (net_ratelimit())
 645                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 646                         goto tx_error;
 647                 }
 648
 649                 addr6 = (struct in6_addr*)&neigh->primary_key;
 650                 addr_type = ipv6_addr_type(addr6);
 651
 652                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 653                      ipv6_addr_is_isatap(addr6))
 654                         dst = addr6->s6_addr32[3];
 655                 else
 656                         goto tx_error;
 657         }
 658
 659         if (!dst)
 660                 dst = try_6to4(&iph6->daddr);
 661
 662         if (!dst) {
 663                 struct neighbour *neigh = NULL;
 664
 665                 if (skb_dst(skb))
 666                         neigh = skb_dst(skb)->neighbour;
 667
 668                 if (neigh == NULL) {
 669                         if (net_ratelimit())
 670                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 671                         goto tx_error;
 672                 }
 673
 674                 addr6 = (struct in6_addr*)&neigh->primary_key;
 675                 addr_type = ipv6_addr_type(addr6);
 676
 677                 if (addr_type == IPV6_ADDR_ANY) {
 678                         addr6 = &ipv6_hdr(skb)->daddr;
 679                         addr_type = ipv6_addr_type(addr6);
 680                 }
 681
 682                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 683                         goto tx_error_icmp;
 684
 685                 dst = addr6->s6_addr32[3];
 686         }
 687
 688         {
 689                 struct flowi fl = { .nl_u = { .ip4_u =
 690                                               { .daddr = dst,
 691                                                 .saddr = tiph->saddr,
 692                                                 .tos = RT_TOS(tos) } },
 693                                     .oif = tunnel->parms.link,
 694                                     .proto = IPPROTO_IPV6 };
 695                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 696                         stats->tx_carrier_errors++;
 697                         goto tx_error_icmp;
 698                 }
 699         }
 700         if (rt->rt_type != RTN_UNICAST) {
 701                 ip_rt_put(rt);
 702                 stats->tx_carrier_errors++;
 703                 goto tx_error_icmp;
 704         }
 705         tdev = rt->u.dst.dev;
 706
 707         if (tdev == dev) {
 708                 ip_rt_put(rt);
 709                 stats->collisions++;
 710                 goto tx_error;
 711         }
 712
 713         if (tiph->frag_off)
 714                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 715         else
 716                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 717
 718         if (mtu < 68) {
 719                 stats->collisions++;
 720                 ip_rt_put(rt);
 721                 goto tx_error;
 722         }
 723         if (mtu < IPV6_MIN_MTU)
 724                 mtu = IPV6_MIN_MTU;
 725         if (tunnel->parms.iph.daddr && skb_dst(skb))
 726                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 727
 728         if (skb->len > mtu) {
 729                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 730                 ip_rt_put(rt);
 731                 goto tx_error;
 732         }
 733
 734         if (tunnel->err_count > 0) {
 735                 if (time_before(jiffies,
 736                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 737                         tunnel->err_count--;
 738                         dst_link_failure(skb);
 739                 } else
 740                         tunnel->err_count = 0;
 741         }
 742
 743         /*
 744          * Okay, now see if we can stuff it in the buffer as-is.
 745          */
 746         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 747
 748         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 749             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 750                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 751                 if (!new_skb) {
 752                         ip_rt_put(rt);
 753                         stats->tx_dropped++;
 754                         dev_kfree_skb(skb);
 755                         tunnel->recursion--;
 756                         return 0;
 757                 }
 758                 if (skb->sk)
 759                         skb_set_owner_w(new_skb, skb->sk);
 760                 dev_kfree_skb(skb);
 761                 skb = new_skb;
 762                 iph6 = ipv6_hdr(skb);
 763         }
 764
 765         skb->transport_header = skb->network_header;
 766         skb_push(skb, sizeof(struct iphdr));
 767         skb_reset_network_header(skb);
 768         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 769         IPCB(skb)->flags = 0;
 770         skb_dst_drop(skb);
 771         skb_dst_set(skb, &rt->u.dst);
 772
 773         /*
 774          *      Push down and install the IPIP header.
 775          */
 776
 777         iph                     =       ip_hdr(skb);
 778         iph->version            =       4;
 779         iph->ihl                =       sizeof(struct iphdr)>>2;
 780         if (mtu > IPV6_MIN_MTU)
 781                 iph->frag_off   =       htons(IP_DF);
 782         else
 783                 iph->frag_off   =       0;
 784
 785         iph->protocol           =       IPPROTO_IPV6;
 786         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 787         iph->daddr              =       rt->rt_dst;
 788         iph->saddr              =       rt->rt_src;
 789
 790         if ((iph->ttl = tiph->ttl) == 0)
 791                 iph->ttl        =       iph6->hop_limit;
 792
 793         nf_reset(skb);
 794
 795         IPTUNNEL_XMIT();
 796         tunnel->recursion--;
 797         return 0;
 798
 799 tx_error_icmp:
 800         dst_link_failure(skb);
 801 tx_error:
 802         stats->tx_errors++;
 803         dev_kfree_skb(skb);
 804         tunnel->recursion--;
 805         return 0;
 806 }
 807
 808 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 809 {
 810         struct net_device *tdev = NULL;
 811         struct ip_tunnel *tunnel;
 812         struct iphdr *iph;
 813
 814         tunnel = netdev_priv(dev);
 815         iph = &tunnel->parms.iph;
 816
 817         if (iph->daddr) {
 818                 struct flowi fl = { .nl_u = { .ip4_u =
 819                                               { .daddr = iph->daddr,
 820                                                 .saddr = iph->saddr,
 821                                                 .tos = RT_TOS(iph->tos) } },
 822                                     .oif = tunnel->parms.link,
 823                                     .proto = IPPROTO_IPV6 };
 824                 struct rtable *rt;
 825                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 826                         tdev = rt->u.dst.dev;
 827                         ip_rt_put(rt);
 828                 }
 829                 dev->flags |= IFF_POINTOPOINT;
 830         }
 831
 832         if (!tdev && tunnel->parms.link)
 833                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 834
 835         if (tdev) {
 836                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 837                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 838                 if (dev->mtu < IPV6_MIN_MTU)
 839                         dev->mtu = IPV6_MIN_MTU;
 840         }
 841         dev->iflink = tunnel->parms.link;
 842 }
 843
 844 static int
 845 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 846 {
 847         int err = 0;
 848         struct ip_tunnel_parm p;
 849         struct ip_tunnel_prl prl;
 850         struct ip_tunnel *t;
 851         struct net *net = dev_net(dev);
 852         struct sit_net *sitn = net_generic(net, sit_net_id);
 853
 854         switch (cmd) {
 855         case SIOCGETTUNNEL:
 856                 t = NULL;
 857                 if (dev == sitn->fb_tunnel_dev) {
 858                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 859                                 err = -EFAULT;
 860                                 break;
 861                         }
 862                         t = ipip6_tunnel_locate(net, &p, 0);
 863                 }
 864                 if (t == NULL)
 865                         t = netdev_priv(dev);
 866                 memcpy(&p, &t->parms, sizeof(p));
 867                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 868                         err = -EFAULT;
 869                 break;
 870
 871         case SIOCADDTUNNEL:
 872         case SIOCCHGTUNNEL:
 873                 err = -EPERM;
 874                 if (!capable(CAP_NET_ADMIN))
 875                         goto done;
 876
 877                 err = -EFAULT;
 878                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 879                         goto done;
 880
 881                 err = -EINVAL;
 882                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 883                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 884                         goto done;
 885                 if (p.iph.ttl)
 886                         p.iph.frag_off |= htons(IP_DF);
 887
 888                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 889
 890                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 891                         if (t != NULL) {
 892                                 if (t->dev != dev) {
 893                                         err = -EEXIST;
 894                                         break;
 895                                 }
 896                         } else {
 897                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 898                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 899                                         err = -EINVAL;
 900                                         break;
 901                                 }
 902                                 t = netdev_priv(dev);
 903                                 ipip6_tunnel_unlink(sitn, t);
 904                                 t->parms.iph.saddr = p.iph.saddr;
 905                                 t->parms.iph.daddr = p.iph.daddr;
 906                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 907                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 908                                 ipip6_tunnel_link(sitn, t);
 909                                 netdev_state_change(dev);
 910                         }
 911                 }
 912
 913                 if (t) {
 914                         err = 0;
 915                         if (cmd == SIOCCHGTUNNEL) {
 916                                 t->parms.iph.ttl = p.iph.ttl;
 917                                 t->parms.iph.tos = p.iph.tos;
 918                                 if (t->parms.link != p.link) {
 919                                         t->parms.link = p.link;
 920                                         ipip6_tunnel_bind_dev(dev);
 921                                         netdev_state_change(dev);
 922                                 }
 923                         }
 924                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 925                                 err = -EFAULT;
 926                 } else
 927                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 928                 break;
 929
 930         case SIOCDELTUNNEL:
 931                 err = -EPERM;
 932                 if (!capable(CAP_NET_ADMIN))
 933                         goto done;
 934
 935                 if (dev == sitn->fb_tunnel_dev) {
 936                         err = -EFAULT;
 937                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 938                                 goto done;
 939                         err = -ENOENT;
 940                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 941                                 goto done;
 942                         err = -EPERM;
 943                         if (t == netdev_priv(sitn->fb_tunnel_dev))
 944                                 goto done;
 945                         dev = t->dev;
 946                 }
 947                 unregister_netdevice(dev);
 948                 err = 0;
 949                 break;
 950
 951         case SIOCGETPRL:
 952                 err = -EINVAL;
 953                 if (dev == sitn->fb_tunnel_dev)
 954                         goto done;
 955                 err = -ENOENT;
 956                 if (!(t = netdev_priv(dev)))
 957                         goto done;
 958                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
 959                 break;
 960
 961         case SIOCADDPRL:
 962         case SIOCDELPRL:
 963         case SIOCCHGPRL:
 964                 err = -EPERM;
 965                 if (!capable(CAP_NET_ADMIN))
 966                         goto done;
 967                 err = -EINVAL;
 968                 if (dev == sitn->fb_tunnel_dev)
 969                         goto done;
 970                 err = -EFAULT;
 971                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
 972                         goto done;
 973                 err = -ENOENT;
 974                 if (!(t = netdev_priv(dev)))
 975                         goto done;
 976
 977                 switch (cmd) {
 978                 case SIOCDELPRL:
 979                         err = ipip6_tunnel_del_prl(t, &prl);
 980                         break;
 981                 case SIOCADDPRL:
 982                 case SIOCCHGPRL:
 983                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 984                         break;
 985                 }
 986                 netdev_state_change(dev);
 987                 break;
 988
 989         default:
 990                 err = -EINVAL;
 991         }
 992
 993 done:
 994         return err;
 995 }
 996
 997 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 998 {
 999         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1000                 return -EINVAL;
1001         dev->mtu = new_mtu;
1002         return 0;
1003 }
1004
1005 static const struct net_device_ops ipip6_netdev_ops = {
1006         .ndo_uninit     = ipip6_tunnel_uninit,
1007         .ndo_start_xmit = ipip6_tunnel_xmit,
1008         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1009         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1010 };
1011
1012 static void ipip6_tunnel_setup(struct net_device *dev)
1013 {
1014         dev->netdev_ops         = &ipip6_netdev_ops;
1015         dev->destructor         = free_netdev;
1016
1017         dev->type               = ARPHRD_SIT;
1018         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1019         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1020         dev->flags              = IFF_NOARP;
1021         dev->iflink             = 0;
1022         dev->addr_len           = 4;
1023         dev->features           |= NETIF_F_NETNS_LOCAL;
1024 }
1025
1026 static void ipip6_tunnel_init(struct net_device *dev)
1027 {
1028         struct ip_tunnel *tunnel = netdev_priv(dev);
1029
1030         tunnel->dev = dev;
1031         strcpy(tunnel->parms.name, dev->name);
1032
1033         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1034         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1035
1036         ipip6_tunnel_bind_dev(dev);
1037 }
1038
1039 static void ipip6_fb_tunnel_init(struct net_device *dev)
1040 {
1041         struct ip_tunnel *tunnel = netdev_priv(dev);
1042         struct iphdr *iph = &tunnel->parms.iph;
1043         struct net *net = dev_net(dev);
1044         struct sit_net *sitn = net_generic(net, sit_net_id);
1045
1046         tunnel->dev = dev;
1047         strcpy(tunnel->parms.name, dev->name);
1048
1049         iph->version            = 4;
1050         iph->protocol           = IPPROTO_IPV6;
1051         iph->ihl                = 5;
1052         iph->ttl                = 64;
1053
1054         dev_hold(dev);
1055         sitn->tunnels_wc[0]     = tunnel;
1056 }
1057
1058 static struct xfrm_tunnel sit_handler = {
1059         .handler        =       ipip6_rcv,
1060         .err_handler    =       ipip6_err,
1061         .priority       =       1,
1062 };
1063
1064 static void sit_destroy_tunnels(struct sit_net *sitn)
1065 {
1066         int prio;
1067
1068         for (prio = 1; prio < 4; prio++) {
1069                 int h;
1070                 for (h = 0; h < HASH_SIZE; h++) {
1071                         struct ip_tunnel *t;
1072                         while ((t = sitn->tunnels[prio][h]) != NULL)
1073                                 unregister_netdevice(t->dev);
1074                 }
1075         }
1076 }
1077
1078 static int sit_init_net(struct net *net)
1079 {
1080         int err;
1081         struct sit_net *sitn;
1082
1083         err = -ENOMEM;
1084         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1085         if (sitn == NULL)
1086                 goto err_alloc;
1087
1088         err = net_assign_generic(net, sit_net_id, sitn);
1089         if (err < 0)
1090                 goto err_assign;
1091
1092         sitn->tunnels[0] = sitn->tunnels_wc;
1093         sitn->tunnels[1] = sitn->tunnels_l;
1094         sitn->tunnels[2] = sitn->tunnels_r;
1095         sitn->tunnels[3] = sitn->tunnels_r_l;
1096
1097         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1098                                            ipip6_tunnel_setup);
1099         if (!sitn->fb_tunnel_dev) {
1100                 err = -ENOMEM;
1101                 goto err_alloc_dev;
1102         }
1103         dev_net_set(sitn->fb_tunnel_dev, net);
1104
1105         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1106
1107         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1108                 goto err_reg_dev;
1109
1110         return 0;
1111
1112 err_reg_dev:
1113         dev_put(sitn->fb_tunnel_dev);
1114         free_netdev(sitn->fb_tunnel_dev);
1115 err_alloc_dev:
1116         /* nothing */
1117 err_assign:
1118         kfree(sitn);
1119 err_alloc:
1120         return err;
1121 }
1122
1123 static void sit_exit_net(struct net *net)
1124 {
1125         struct sit_net *sitn;
1126
1127         sitn = net_generic(net, sit_net_id);
1128         rtnl_lock();
1129         sit_destroy_tunnels(sitn);
1130         unregister_netdevice(sitn->fb_tunnel_dev);
1131         rtnl_unlock();
1132         kfree(sitn);
1133 }
1134
1135 static struct pernet_operations sit_net_ops = {
1136         .init = sit_init_net,
1137         .exit = sit_exit_net,
1138 };
1139
1140 static void __exit sit_cleanup(void)
1141 {
1142         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1143
1144         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1145 }
1146
1147 static int __init sit_init(void)
1148 {
1149         int err;
1150
1151         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1152
1153         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1154                 printk(KERN_INFO "sit init: Can't add protocol\n");
1155                 return -EAGAIN;
1156         }
1157
1158         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1159         if (err < 0)
1160                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1161
1162         return err;
1163 }
1164
1165 module_init(sit_init);
1166 module_exit(sit_cleanup);
1167 MODULE_LICENSE("GPL");
1168 MODULE_ALIAS("sit0");