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  *      $Id: sit.c,v 1.53 2001/09/25 05:09:53 davem Exp $
  10  *
  11  *      This program is free software; you can redistribute it and/or
  12  *      modify it under the terms of the GNU General Public License
  13  *      as published by the Free Software Foundation; either version
  14  *      2 of the License, or (at your option) any later version.
  15  *
  16  *      Changes:
  17  * Roger Venning <r.venning@telstra.com>:       6to4 support
  18  * Nate Thompson <nate@thebog.net>:             6to4 support
  19  */
  20
  21 #include <linux/config.h>
  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/sched.h>
  29 #include <linux/net.h>
  30 #include <linux/in6.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/icmp.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
  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) ((addr^(addr>>4))&0xF)
  65
  66 static int ipip6_fb_tunnel_init(struct net_device *dev);
  67 static int ipip6_tunnel_init(struct net_device *dev);
  68 static void ipip6_tunnel_setup(struct net_device *dev);
  69
  70 static struct net_device *ipip6_fb_tunnel_dev;
  71
  72 static struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  73 static struct ip_tunnel *tunnels_r[HASH_SIZE];
  74 static struct ip_tunnel *tunnels_l[HASH_SIZE];
  75 static struct ip_tunnel *tunnels_wc[1];
  76 static struct ip_tunnel **tunnels[4] = { tunnels_wc, tunnels_l, tunnels_r, tunnels_r_l };
  77
  78 static DEFINE_RWLOCK(ipip6_lock);
  79
  80 static struct ip_tunnel * ipip6_tunnel_lookup(u32 remote, u32 local)
  81 {
  82         unsigned h0 = HASH(remote);
  83         unsigned h1 = HASH(local);
  84         struct ip_tunnel *t;
  85
  86         for (t = tunnels_r_l[h0^h1]; t; t = t->next) {
  87                 if (local == t->parms.iph.saddr &&
  88                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  89                         return t;
  90         }
  91         for (t = tunnels_r[h0]; t; t = t->next) {
  92                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  93                         return t;
  94         }
  95         for (t = tunnels_l[h1]; t; t = t->next) {
  96                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
  97                         return t;
  98         }
  99         if ((t = tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
 100                 return t;
 101         return NULL;
 102 }
 103
 104 static struct ip_tunnel ** ipip6_bucket(struct ip_tunnel *t)
 105 {
 106         u32 remote = t->parms.iph.daddr;
 107         u32 local = t->parms.iph.saddr;
 108         unsigned h = 0;
 109         int prio = 0;
 110
 111         if (remote) {
 112                 prio |= 2;
 113                 h ^= HASH(remote);
 114         }
 115         if (local) {
 116                 prio |= 1;
 117                 h ^= HASH(local);
 118         }
 119         return &tunnels[prio][h];
 120 }
 121
 122 static void ipip6_tunnel_unlink(struct ip_tunnel *t)
 123 {
 124         struct ip_tunnel **tp;
 125
 126         for (tp = ipip6_bucket(t); *tp; tp = &(*tp)->next) {
 127                 if (t == *tp) {
 128                         write_lock_bh(&ipip6_lock);
 129                         *tp = t->next;
 130                         write_unlock_bh(&ipip6_lock);
 131                         break;
 132                 }
 133         }
 134 }
 135
 136 static void ipip6_tunnel_link(struct ip_tunnel *t)
 137 {
 138         struct ip_tunnel **tp = ipip6_bucket(t);
 139
 140         t->next = *tp;
 141         write_lock_bh(&ipip6_lock);
 142         *tp = t;
 143         write_unlock_bh(&ipip6_lock);
 144 }
 145
 146 static struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int create)
 147 {
 148         u32 remote = parms->iph.daddr;
 149         u32 local = parms->iph.saddr;
 150         struct ip_tunnel *t, **tp, *nt;
 151         struct net_device *dev;
 152         unsigned h = 0;
 153         int prio = 0;
 154         char name[IFNAMSIZ];
 155
 156         if (remote) {
 157                 prio |= 2;
 158                 h ^= HASH(remote);
 159         }
 160         if (local) {
 161                 prio |= 1;
 162                 h ^= HASH(local);
 163         }
 164         for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
 165                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
 166                         return t;
 167         }
 168         if (!create)
 169                 goto failed;
 170
 171         if (parms->name[0])
 172                 strlcpy(name, parms->name, IFNAMSIZ);
 173         else {
 174                 int i;
 175                 for (i=1; i<100; i++) {
 176                         sprintf(name, "sit%d", i);
 177                         if (__dev_get_by_name(name) == NULL)
 178                                 break;
 179                 }
 180                 if (i==100)
 181                         goto failed;
 182         }
 183
 184         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 185         if (dev == NULL)
 186                 return NULL;
 187
 188         nt = netdev_priv(dev);
 189         dev->init = ipip6_tunnel_init;
 190         nt->parms = *parms;
 191
 192         if (register_netdevice(dev) < 0) {
 193                 free_netdev(dev);
 194                 goto failed;
 195         }
 196
 197         dev_hold(dev);
 198
 199         ipip6_tunnel_link(nt);
 200         return nt;
 201
 202 failed:
 203         return NULL;
 204 }
 205
 206 static void ipip6_tunnel_uninit(struct net_device *dev)
 207 {
 208         if (dev == ipip6_fb_tunnel_dev) {
 209                 write_lock_bh(&ipip6_lock);
 210                 tunnels_wc[0] = NULL;
 211                 write_unlock_bh(&ipip6_lock);
 212                 dev_put(dev);
 213         } else {
 214                 ipip6_tunnel_unlink(netdev_priv(dev));
 215                 dev_put(dev);
 216         }
 217 }
 218
 219
 220 static void ipip6_err(struct sk_buff *skb, u32 info)
 221 {
 222 #ifndef I_WISH_WORLD_WERE_PERFECT
 223
 224 /* It is not :-( All the routers (except for Linux) return only
 225    8 bytes of packet payload. It means, that precise relaying of
 226    ICMP in the real Internet is absolutely infeasible.
 227  */
 228         struct iphdr *iph = (struct iphdr*)skb->data;
 229         int type = skb->h.icmph->type;
 230         int code = skb->h.icmph->code;
 231         struct ip_tunnel *t;
 232
 233         switch (type) {
 234         default:
 235         case ICMP_PARAMETERPROB:
 236                 return;
 237
 238         case ICMP_DEST_UNREACH:
 239                 switch (code) {
 240                 case ICMP_SR_FAILED:
 241                 case ICMP_PORT_UNREACH:
 242                         /* Impossible event. */
 243                         return;
 244                 case ICMP_FRAG_NEEDED:
 245                         /* Soft state for pmtu is maintained by IP core. */
 246                         return;
 247                 default:
 248                         /* All others are translated to HOST_UNREACH.
 249                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 250                            I believe they are just ether pollution. --ANK
 251                          */
 252                         break;
 253                 }
 254                 break;
 255         case ICMP_TIME_EXCEEDED:
 256                 if (code != ICMP_EXC_TTL)
 257                         return;
 258                 break;
 259         }
 260
 261         read_lock(&ipip6_lock);
 262         t = ipip6_tunnel_lookup(iph->daddr, iph->saddr);
 263         if (t == NULL || t->parms.iph.daddr == 0)
 264                 goto out;
 265         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 266                 goto out;
 267
 268         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
 269                 t->err_count++;
 270         else
 271                 t->err_count = 1;
 272         t->err_time = jiffies;
 273 out:
 274         read_unlock(&ipip6_lock);
 275         return;
 276 #else
 277         struct iphdr *iph = (struct iphdr*)dp;
 278         int hlen = iph->ihl<<2;
 279         struct ipv6hdr *iph6;
 280         int type = skb->h.icmph->type;
 281         int code = skb->h.icmph->code;
 282         int rel_type = 0;
 283         int rel_code = 0;
 284         int rel_info = 0;
 285         struct sk_buff *skb2;
 286         struct rt6_info *rt6i;
 287
 288         if (len < hlen + sizeof(struct ipv6hdr))
 289                 return;
 290         iph6 = (struct ipv6hdr*)(dp + hlen);
 291
 292         switch (type) {
 293         default:
 294                 return;
 295         case ICMP_PARAMETERPROB:
 296                 if (skb->h.icmph->un.gateway < hlen)
 297                         return;
 298
 299                 /* So... This guy found something strange INSIDE encapsulated
 300                    packet. Well, he is fool, but what can we do ?
 301                  */
 302                 rel_type = ICMPV6_PARAMPROB;
 303                 rel_info = skb->h.icmph->un.gateway - hlen;
 304                 break;
 305
 306         case ICMP_DEST_UNREACH:
 307                 switch (code) {
 308                 case ICMP_SR_FAILED:
 309                 case ICMP_PORT_UNREACH:
 310                         /* Impossible event. */
 311                         return;
 312                 case ICMP_FRAG_NEEDED:
 313                         /* Too complicated case ... */
 314                         return;
 315                 default:
 316                         /* All others are translated to HOST_UNREACH.
 317                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 318                            I believe, it is just ether pollution. --ANK
 319                          */
 320                         rel_type = ICMPV6_DEST_UNREACH;
 321                         rel_code = ICMPV6_ADDR_UNREACH;
 322                         break;
 323                 }
 324                 break;
 325         case ICMP_TIME_EXCEEDED:
 326                 if (code != ICMP_EXC_TTL)
 327                         return;
 328                 rel_type = ICMPV6_TIME_EXCEED;
 329                 rel_code = ICMPV6_EXC_HOPLIMIT;
 330                 break;
 331         }
 332
 333         /* Prepare fake skb to feed it to icmpv6_send */
 334         skb2 = skb_clone(skb, GFP_ATOMIC);
 335         if (skb2 == NULL)
 336                 return;
 337         dst_release(skb2->dst);
 338         skb2->dst = NULL;
 339         skb_pull(skb2, skb->data - (u8*)iph6);
 340         skb2->nh.raw = skb2->data;
 341
 342         /* Try to guess incoming interface */
 343         rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0);
 344         if (rt6i && rt6i->rt6i_dev) {
 345                 skb2->dev = rt6i->rt6i_dev;
 346
 347                 rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0);
 348
 349                 if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
 350                         struct ip_tunnel *t = netdev_priv(rt6i->rt6i_dev);
 351                         if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
 352                                 rel_type = ICMPV6_DEST_UNREACH;
 353                                 rel_code = ICMPV6_ADDR_UNREACH;
 354                         }
 355                         icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
 356                 }
 357         }
 358         kfree_skb(skb2);
 359         return;
 360 #endif
 361 }
 362
 363 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 364 {
 365         if (INET_ECN_is_ce(iph->tos))
 366                 IP6_ECN_set_ce(skb->nh.ipv6h);
 367 }
 368
 369 static int ipip6_rcv(struct sk_buff *skb)
 370 {
 371         struct iphdr *iph;
 372         struct ip_tunnel *tunnel;
 373
 374         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 375                 goto out;
 376
 377         iph = skb->nh.iph;
 378
 379         read_lock(&ipip6_lock);
 380         if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
 381                 secpath_reset(skb);
 382                 skb->mac.raw = skb->nh.raw;
 383                 skb->nh.raw = skb->data;
 384                 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
 385                 IPCB(skb)->flags = 0;
 386                 skb->protocol = htons(ETH_P_IPV6);
 387                 skb->pkt_type = PACKET_HOST;
 388                 tunnel->stat.rx_packets++;
 389                 tunnel->stat.rx_bytes += skb->len;
 390                 skb->dev = tunnel->dev;
 391                 dst_release(skb->dst);
 392                 skb->dst = NULL;
 393                 nf_reset(skb);
 394                 ipip6_ecn_decapsulate(iph, skb);
 395                 netif_rx(skb);
 396                 read_unlock(&ipip6_lock);
 397                 return 0;
 398         }
 399
 400         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
 401         kfree_skb(skb);
 402         read_unlock(&ipip6_lock);
 403 out:
 404         return 0;
 405 }
 406
 407 /* Returns the embedded IPv4 address if the IPv6 address
 408    comes from 6to4 (RFC 3056) addr space */
 409
 410 static inline u32 try_6to4(struct in6_addr *v6dst)
 411 {
 412         u32 dst = 0;
 413
 414         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 415                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 416                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 417         }
 418         return dst;
 419 }
 420
 421 /*
 422  *      This function assumes it is being called from dev_queue_xmit()
 423  *      and that skb is filled properly by that function.
 424  */
 425
 426 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 427 {
 428         struct ip_tunnel *tunnel = netdev_priv(dev);
 429         struct net_device_stats *stats = &tunnel->stat;
 430         struct iphdr  *tiph = &tunnel->parms.iph;
 431         struct ipv6hdr *iph6 = skb->nh.ipv6h;
 432         u8     tos = tunnel->parms.iph.tos;
 433         struct rtable *rt;                      /* Route to the other host */
 434         struct net_device *tdev;                        /* Device to other host */
 435         struct iphdr  *iph;                     /* Our new IP header */
 436         int    max_headroom;                    /* The extra header space needed */
 437         u32    dst = tiph->daddr;
 438         int    mtu;
 439         struct in6_addr *addr6;
 440         int addr_type;
 441
 442         if (tunnel->recursion++) {
 443                 tunnel->stat.collisions++;
 444                 goto tx_error;
 445         }
 446
 447         if (skb->protocol != htons(ETH_P_IPV6))
 448                 goto tx_error;
 449
 450         if (!dst)
 451                 dst = try_6to4(&iph6->daddr);
 452
 453         if (!dst) {
 454                 struct neighbour *neigh = NULL;
 455
 456                 if (skb->dst)
 457                         neigh = skb->dst->neighbour;
 458
 459                 if (neigh == NULL) {
 460                         if (net_ratelimit())
 461                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 462                         goto tx_error;
 463                 }
 464
 465                 addr6 = (struct in6_addr*)&neigh->primary_key;
 466                 addr_type = ipv6_addr_type(addr6);
 467
 468                 if (addr_type == IPV6_ADDR_ANY) {
 469                         addr6 = &skb->nh.ipv6h->daddr;
 470                         addr_type = ipv6_addr_type(addr6);
 471                 }
 472
 473                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 474                         goto tx_error_icmp;
 475
 476                 dst = addr6->s6_addr32[3];
 477         }
 478
 479         {
 480                 struct flowi fl = { .nl_u = { .ip4_u =
 481                                               { .daddr = dst,
 482                                                 .saddr = tiph->saddr,
 483                                                 .tos = RT_TOS(tos) } },
 484                                     .oif = tunnel->parms.link,
 485                                     .proto = IPPROTO_IPV6 };
 486                 if (ip_route_output_key(&rt, &fl)) {
 487                         tunnel->stat.tx_carrier_errors++;
 488                         goto tx_error_icmp;
 489                 }
 490         }
 491         if (rt->rt_type != RTN_UNICAST) {
 492                 ip_rt_put(rt);
 493                 tunnel->stat.tx_carrier_errors++;
 494                 goto tx_error_icmp;
 495         }
 496         tdev = rt->u.dst.dev;
 497
 498         if (tdev == dev) {
 499                 ip_rt_put(rt);
 500                 tunnel->stat.collisions++;
 501                 goto tx_error;
 502         }
 503
 504         if (tiph->frag_off)
 505                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 506         else
 507                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
 508
 509         if (mtu < 68) {
 510                 tunnel->stat.collisions++;
 511                 ip_rt_put(rt);
 512                 goto tx_error;
 513         }
 514         if (mtu < IPV6_MIN_MTU)
 515                 mtu = IPV6_MIN_MTU;
 516         if (tunnel->parms.iph.daddr && skb->dst)
 517                 skb->dst->ops->update_pmtu(skb->dst, mtu);
 518
 519         if (skb->len > mtu) {
 520                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 521                 ip_rt_put(rt);
 522                 goto tx_error;
 523         }
 524
 525         if (tunnel->err_count > 0) {
 526                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
 527                         tunnel->err_count--;
 528                         dst_link_failure(skb);
 529                 } else
 530                         tunnel->err_count = 0;
 531         }
 532
 533         /*
 534          * Okay, now see if we can stuff it in the buffer as-is.
 535          */
 536         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 537
 538         if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
 539                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 540                 if (!new_skb) {
 541                         ip_rt_put(rt);
 542                         stats->tx_dropped++;
 543                         dev_kfree_skb(skb);
 544                         tunnel->recursion--;
 545                         return 0;
 546                 }
 547                 if (skb->sk)
 548                         skb_set_owner_w(new_skb, skb->sk);
 549                 dev_kfree_skb(skb);
 550                 skb = new_skb;
 551                 iph6 = skb->nh.ipv6h;
 552         }
 553
 554         skb->h.raw = skb->nh.raw;
 555         skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
 556         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 557         IPCB(skb)->flags = 0;
 558         dst_release(skb->dst);
 559         skb->dst = &rt->u.dst;
 560
 561         /*
 562          *      Push down and install the IPIP header.
 563          */
 564
 565         iph                     =       skb->nh.iph;
 566         iph->version            =       4;
 567         iph->ihl                =       sizeof(struct iphdr)>>2;
 568         if (mtu > IPV6_MIN_MTU)
 569                 iph->frag_off   =       htons(IP_DF);
 570         else
 571                 iph->frag_off   =       0;
 572
 573         iph->protocol           =       IPPROTO_IPV6;
 574         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 575         iph->daddr              =       rt->rt_dst;
 576         iph->saddr              =       rt->rt_src;
 577
 578         if ((iph->ttl = tiph->ttl) == 0)
 579                 iph->ttl        =       iph6->hop_limit;
 580
 581         nf_reset(skb);
 582
 583         IPTUNNEL_XMIT();
 584         tunnel->recursion--;
 585         return 0;
 586
 587 tx_error_icmp:
 588         dst_link_failure(skb);
 589 tx_error:
 590         stats->tx_errors++;
 591         dev_kfree_skb(skb);
 592         tunnel->recursion--;
 593         return 0;
 594 }
 595
 596 static int
 597 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 598 {
 599         int err = 0;
 600         struct ip_tunnel_parm p;
 601         struct ip_tunnel *t;
 602
 603         switch (cmd) {
 604         case SIOCGETTUNNEL:
 605                 t = NULL;
 606                 if (dev == ipip6_fb_tunnel_dev) {
 607                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 608                                 err = -EFAULT;
 609                                 break;
 610                         }
 611                         t = ipip6_tunnel_locate(&p, 0);
 612                 }
 613                 if (t == NULL)
 614                         t = netdev_priv(dev);
 615                 memcpy(&p, &t->parms, sizeof(p));
 616                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 617                         err = -EFAULT;
 618                 break;
 619
 620         case SIOCADDTUNNEL:
 621         case SIOCCHGTUNNEL:
 622                 err = -EPERM;
 623                 if (!capable(CAP_NET_ADMIN))
 624                         goto done;
 625
 626                 err = -EFAULT;
 627                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 628                         goto done;
 629
 630                 err = -EINVAL;
 631                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 632                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 633                         goto done;
 634                 if (p.iph.ttl)
 635                         p.iph.frag_off |= htons(IP_DF);
 636
 637                 t = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL);
 638
 639                 if (dev != ipip6_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 640                         if (t != NULL) {
 641                                 if (t->dev != dev) {
 642                                         err = -EEXIST;
 643                                         break;
 644                                 }
 645                         } else {
 646                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 647                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 648                                         err = -EINVAL;
 649                                         break;
 650                                 }
 651                                 t = netdev_priv(dev);
 652                                 ipip6_tunnel_unlink(t);
 653                                 t->parms.iph.saddr = p.iph.saddr;
 654                                 t->parms.iph.daddr = p.iph.daddr;
 655                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 656                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 657                                 ipip6_tunnel_link(t);
 658                                 netdev_state_change(dev);
 659                         }
 660                 }
 661
 662                 if (t) {
 663                         err = 0;
 664                         if (cmd == SIOCCHGTUNNEL) {
 665                                 t->parms.iph.ttl = p.iph.ttl;
 666                                 t->parms.iph.tos = p.iph.tos;
 667                         }
 668                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 669                                 err = -EFAULT;
 670                 } else
 671                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 672                 break;
 673
 674         case SIOCDELTUNNEL:
 675                 err = -EPERM;
 676                 if (!capable(CAP_NET_ADMIN))
 677                         goto done;
 678
 679                 if (dev == ipip6_fb_tunnel_dev) {
 680                         err = -EFAULT;
 681                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 682                                 goto done;
 683                         err = -ENOENT;
 684                         if ((t = ipip6_tunnel_locate(&p, 0)) == NULL)
 685                                 goto done;
 686                         err = -EPERM;
 687                         if (t == netdev_priv(ipip6_fb_tunnel_dev))
 688                                 goto done;
 689                         dev = t->dev;
 690                 }
 691                 err = unregister_netdevice(dev);
 692                 break;
 693
 694         default:
 695                 err = -EINVAL;
 696         }
 697
 698 done:
 699         return err;
 700 }
 701
 702 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev)
 703 {
 704         return &(((struct ip_tunnel*)netdev_priv(dev))->stat);
 705 }
 706
 707 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 708 {
 709         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 710                 return -EINVAL;
 711         dev->mtu = new_mtu;
 712         return 0;
 713 }
 714
 715 static void ipip6_tunnel_setup(struct net_device *dev)
 716 {
 717         SET_MODULE_OWNER(dev);
 718         dev->uninit             = ipip6_tunnel_uninit;
 719         dev->destructor         = free_netdev;
 720         dev->hard_start_xmit    = ipip6_tunnel_xmit;
 721         dev->get_stats          = ipip6_tunnel_get_stats;
 722         dev->do_ioctl           = ipip6_tunnel_ioctl;
 723         dev->change_mtu         = ipip6_tunnel_change_mtu;
 724
 725         dev->type               = ARPHRD_SIT;
 726         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 727         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 728         dev->flags              = IFF_NOARP;
 729         dev->iflink             = 0;
 730         dev->addr_len           = 4;
 731 }
 732
 733 static int ipip6_tunnel_init(struct net_device *dev)
 734 {
 735         struct net_device *tdev = NULL;
 736         struct ip_tunnel *tunnel;
 737         struct iphdr *iph;
 738
 739         tunnel = netdev_priv(dev);
 740         iph = &tunnel->parms.iph;
 741
 742         tunnel->dev = dev;
 743         strcpy(tunnel->parms.name, dev->name);
 744
 745         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 746         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 747
 748         if (iph->daddr) {
 749                 struct flowi fl = { .nl_u = { .ip4_u =
 750                                               { .daddr = iph->daddr,
 751                                                 .saddr = iph->saddr,
 752                                                 .tos = RT_TOS(iph->tos) } },
 753                                     .oif = tunnel->parms.link,
 754                                     .proto = IPPROTO_IPV6 };
 755                 struct rtable *rt;
 756                 if (!ip_route_output_key(&rt, &fl)) {
 757                         tdev = rt->u.dst.dev;
 758                         ip_rt_put(rt);
 759                 }
 760                 dev->flags |= IFF_POINTOPOINT;
 761         }
 762
 763         if (!tdev && tunnel->parms.link)
 764                 tdev = __dev_get_by_index(tunnel->parms.link);
 765
 766         if (tdev) {
 767                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 768                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 769                 if (dev->mtu < IPV6_MIN_MTU)
 770                         dev->mtu = IPV6_MIN_MTU;
 771         }
 772         dev->iflink = tunnel->parms.link;
 773
 774         return 0;
 775 }
 776
 777 static int __init ipip6_fb_tunnel_init(struct net_device *dev)
 778 {
 779         struct ip_tunnel *tunnel = netdev_priv(dev);
 780         struct iphdr *iph = &tunnel->parms.iph;
 781
 782         tunnel->dev = dev;
 783         strcpy(tunnel->parms.name, dev->name);
 784
 785         iph->version            = 4;
 786         iph->protocol           = IPPROTO_IPV6;
 787         iph->ihl                = 5;
 788         iph->ttl                = 64;
 789
 790         dev_hold(dev);
 791         tunnels_wc[0]           = tunnel;
 792         return 0;
 793 }
 794
 795 static struct net_protocol sit_protocol = {
 796         .handler        =       ipip6_rcv,
 797         .err_handler    =       ipip6_err,
 798 };
 799
 800 static void __exit sit_destroy_tunnels(void)
 801 {
 802         int prio;
 803
 804         for (prio = 1; prio < 4; prio++) {
 805                 int h;
 806                 for (h = 0; h < HASH_SIZE; h++) {
 807                         struct ip_tunnel *t;
 808                         while ((t = tunnels[prio][h]) != NULL)
 809                                 unregister_netdevice(t->dev);
 810                 }
 811         }
 812 }
 813
 814 void __exit sit_cleanup(void)
 815 {
 816         inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
 817
 818         rtnl_lock();
 819         sit_destroy_tunnels();
 820         unregister_netdevice(ipip6_fb_tunnel_dev);
 821         rtnl_unlock();
 822 }
 823
 824 int __init sit_init(void)
 825 {
 826         int err;
 827
 828         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
 829
 830         if (inet_add_protocol(&sit_protocol, IPPROTO_IPV6) < 0) {
 831                 printk(KERN_INFO "sit init: Can't add protocol\n");
 832                 return -EAGAIN;
 833         }
 834
 835         ipip6_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
 836                                            ipip6_tunnel_setup);
 837         if (!ipip6_fb_tunnel_dev) {
 838                 err = -ENOMEM;
 839                 goto err1;
 840         }
 841
 842         ipip6_fb_tunnel_dev->init = ipip6_fb_tunnel_init;
 843
 844         if ((err =  register_netdev(ipip6_fb_tunnel_dev)))
 845                 goto err2;
 846
 847  out:
 848         return err;
 849  err2:
 850         free_netdev(ipip6_fb_tunnel_dev);
 851  err1:
 852         inet_del_protocol(&sit_protocol, IPPROTO_IPV6);
 853         goto out;
 854 }