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 1.42 2000/08/02 06:03:59 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
  17 #define __NO_VERSION__
  18 #include <linux/config.h>
  19 #include <linux/module.h>
  20 #include <linux/errno.h>
  21 #include <linux/types.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/sched.h>
  25 #include <linux/net.h>
  26 #include <linux/in6.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/if_arp.h>
  29 #include <linux/icmp.h>
  30 #include <asm/uaccess.h>
  31 #include <linux/init.h>
  32 #include <linux/netfilter_ipv4.h>
  33
  34 #include <net/sock.h>
  35 #include <net/snmp.h>
  36
  37 #include <net/ipv6.h>
  38 #include <net/protocol.h>
  39 #include <net/transp_v6.h>
  40 #include <net/ip6_fib.h>
  41 #include <net/ip6_route.h>
  42 #include <net/ndisc.h>
  43 #include <net/addrconf.h>
  44 #include <net/ip.h>
  45 #include <net/udp.h>
  46 #include <net/icmp.h>
  47 #include <net/ipip.h>
  48 #include <net/inet_ecn.h>
  49
  50 /*
  51    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  52
  53    For comments look at net/ipv4/ip_gre.c --ANK
  54  */
  55
  56 #define HASH_SIZE  16
  57 #define HASH(addr) ((addr^(addr>>4))&0xF)
  58
  59 static int ipip6_fb_tunnel_init(struct net_device *dev);
  60 static int ipip6_tunnel_init(struct net_device *dev);
  61
  62 static struct net_device ipip6_fb_tunnel_dev = {
  63         "sit0", 0x0, 0x0, 0x0, 0x0, 0, 0, 0, 0, 0, NULL, ipip6_fb_tunnel_init,
  64 };
  65
  66 static struct ip_tunnel ipip6_fb_tunnel = {
  67         NULL, &ipip6_fb_tunnel_dev, {0, }, 0, 0, 0, 0, 0, 0, 0, {"sit0", }
  68 };
  69
  70 static struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  71 static struct ip_tunnel *tunnels_r[HASH_SIZE];
  72 static struct ip_tunnel *tunnels_l[HASH_SIZE];
  73 static struct ip_tunnel *tunnels_wc[1];
  74 static struct ip_tunnel **tunnels[4] = { tunnels_wc, tunnels_l, tunnels_r, tunnels_r_l };
  75
  76 static rwlock_t ipip6_lock = RW_LOCK_UNLOCKED;
  77
  78 static struct ip_tunnel * ipip6_tunnel_lookup(u32 remote, u32 local)
  79 {
  80         unsigned h0 = HASH(remote);
  81         unsigned h1 = HASH(local);
  82         struct ip_tunnel *t;
  83
  84         for (t = tunnels_r_l[h0^h1]; t; t = t->next) {
  85                 if (local == t->parms.iph.saddr &&
  86                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  87                         return t;
  88         }
  89         for (t = tunnels_r[h0]; t; t = t->next) {
  90                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  91                         return t;
  92         }
  93         for (t = tunnels_l[h1]; t; t = t->next) {
  94                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
  95                         return t;
  96         }
  97         if ((t = tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
  98                 return t;
  99         return NULL;
 100 }
 101
 102 static struct ip_tunnel ** ipip6_bucket(struct ip_tunnel *t)
 103 {
 104         u32 remote = t->parms.iph.daddr;
 105         u32 local = t->parms.iph.saddr;
 106         unsigned h = 0;
 107         int prio = 0;
 108
 109         if (remote) {
 110                 prio |= 2;
 111                 h ^= HASH(remote);
 112         }
 113         if (local) {
 114                 prio |= 1;
 115                 h ^= HASH(local);
 116         }
 117         return &tunnels[prio][h];
 118 }
 119
 120 static void ipip6_tunnel_unlink(struct ip_tunnel *t)
 121 {
 122         struct ip_tunnel **tp;
 123
 124         for (tp = ipip6_bucket(t); *tp; tp = &(*tp)->next) {
 125                 if (t == *tp) {
 126                         write_lock_bh(&ipip6_lock);
 127                         *tp = t->next;
 128                         write_unlock_bh(&ipip6_lock);
 129                         break;
 130                 }
 131         }
 132 }
 133
 134 static void ipip6_tunnel_link(struct ip_tunnel *t)
 135 {
 136         struct ip_tunnel **tp = ipip6_bucket(t);
 137
 138         write_lock_bh(&ipip6_lock);
 139         t->next = *tp;
 140         write_unlock_bh(&ipip6_lock);
 141         *tp = t;
 142 }
 143
 144 struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int create)
 145 {
 146         u32 remote = parms->iph.daddr;
 147         u32 local = parms->iph.saddr;
 148         struct ip_tunnel *t, **tp, *nt;
 149         struct net_device *dev;
 150         unsigned h = 0;
 151         int prio = 0;
 152
 153         if (remote) {
 154                 prio |= 2;
 155                 h ^= HASH(remote);
 156         }
 157         if (local) {
 158                 prio |= 1;
 159                 h ^= HASH(local);
 160         }
 161         for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) {
 162                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
 163                         return t;
 164         }
 165         if (!create)
 166                 return NULL;
 167
 168         MOD_INC_USE_COUNT;
 169         dev = kmalloc(sizeof(*dev) + sizeof(*t), GFP_KERNEL);
 170         if (dev == NULL) {
 171                 MOD_DEC_USE_COUNT;
 172                 return NULL;
 173         }
 174         memset(dev, 0, sizeof(*dev) + sizeof(*t));
 175         dev->priv = (void*)(dev+1);
 176         nt = (struct ip_tunnel*)dev->priv;
 177         nt->dev = dev;
 178         dev->init = ipip6_tunnel_init;
 179         dev->new_style = 1;
 180         memcpy(&nt->parms, parms, sizeof(*parms));
 181         strcpy(dev->name, nt->parms.name);
 182         if (dev->name[0] == 0) {
 183                 int i;
 184                 for (i=1; i<100; i++) {
 185                         sprintf(dev->name, "sit%d", i);
 186                         if (__dev_get_by_name(dev->name) == NULL)
 187                                 break;
 188                 }
 189                 if (i==100)
 190                         goto failed;
 191                 memcpy(parms->name, dev->name, IFNAMSIZ);
 192         }
 193         if (register_netdevice(dev) < 0)
 194                 goto failed;
 195
 196         dev_hold(dev);
 197         ipip6_tunnel_link(nt);
 198         /* Do not decrement MOD_USE_COUNT here. */
 199         return nt;
 200
 201 failed:
 202         kfree(dev);
 203         MOD_DEC_USE_COUNT;
 204         return NULL;
 205 }
 206
 207 static void ipip6_tunnel_destructor(struct net_device *dev)
 208 {
 209         if (dev != &ipip6_fb_tunnel_dev) {
 210                 MOD_DEC_USE_COUNT;
 211         }
 212 }
 213
 214 static void ipip6_tunnel_uninit(struct net_device *dev)
 215 {
 216         if (dev == &ipip6_fb_tunnel_dev) {
 217                 write_lock_bh(&ipip6_lock);
 218                 tunnels_wc[0] = NULL;
 219                 write_unlock_bh(&ipip6_lock);
 220                 dev_put(dev);
 221         } else {
 222                 ipip6_tunnel_unlink((struct ip_tunnel*)dev->priv);
 223                 dev_put(dev);
 224         }
 225 }
 226
 227
 228 void ipip6_err(struct sk_buff *skb, unsigned char *dp, int len)
 229 {
 230 #ifndef I_WISH_WORLD_WERE_PERFECT
 231
 232 /* It is not :-( All the routers (except for Linux) return only
 233    8 bytes of packet payload. It means, that precise relaying of
 234    ICMP in the real Internet is absolutely infeasible.
 235  */
 236         struct iphdr *iph = (struct iphdr*)dp;
 237         int type = skb->h.icmph->type;
 238         int code = skb->h.icmph->code;
 239         struct ip_tunnel *t;
 240
 241         if (len < sizeof(struct iphdr))
 242                 return;
 243
 244         switch (type) {
 245         default:
 246         case ICMP_PARAMETERPROB:
 247                 return;
 248
 249         case ICMP_DEST_UNREACH:
 250                 switch (code) {
 251                 case ICMP_SR_FAILED:
 252                 case ICMP_PORT_UNREACH:
 253                         /* Impossible event. */
 254                         return;
 255                 case ICMP_FRAG_NEEDED:
 256                         /* Soft state for pmtu is maintained by IP core. */
 257                         return;
 258                 default:
 259                         /* All others are translated to HOST_UNREACH.
 260                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 261                            I believe they are just ether pollution. --ANK
 262                          */
 263                         break;
 264                 }
 265                 break;
 266         case ICMP_TIME_EXCEEDED:
 267                 if (code != ICMP_EXC_TTL)
 268                         return;
 269                 break;
 270         }
 271
 272         read_lock(&ipip6_lock);
 273         t = ipip6_tunnel_lookup(iph->daddr, iph->saddr);
 274         if (t == NULL || t->parms.iph.daddr == 0)
 275                 goto out;
 276         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 277                 goto out;
 278
 279         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
 280                 t->err_count++;
 281         else
 282                 t->err_count = 1;
 283         t->err_time = jiffies;
 284 out:
 285         read_unlock(&ipip6_lock);
 286         return;
 287 #else
 288         struct iphdr *iph = (struct iphdr*)dp;
 289         int hlen = iph->ihl<<2;
 290         struct ipv6hdr *iph6;
 291         int type = skb->h.icmph->type;
 292         int code = skb->h.icmph->code;
 293         int rel_type = 0;
 294         int rel_code = 0;
 295         int rel_info = 0;
 296         struct sk_buff *skb2;
 297         struct rt6_info *rt6i;
 298
 299         if (len < hlen + sizeof(struct ipv6hdr))
 300                 return;
 301         iph6 = (struct ipv6hdr*)(dp + hlen);
 302
 303         switch (type) {
 304         default:
 305                 return;
 306         case ICMP_PARAMETERPROB:
 307                 if (skb->h.icmph->un.gateway < hlen)
 308                         return;
 309
 310                 /* So... This guy found something strange INSIDE encapsulated
 311                    packet. Well, he is fool, but what can we do ?
 312                  */
 313                 rel_type = ICMPV6_PARAMPROB;
 314                 rel_info = skb->h.icmph->un.gateway - hlen;
 315                 break;
 316
 317         case ICMP_DEST_UNREACH:
 318                 switch (code) {
 319                 case ICMP_SR_FAILED:
 320                 case ICMP_PORT_UNREACH:
 321                         /* Impossible event. */
 322                         return;
 323                 case ICMP_FRAG_NEEDED:
 324                         /* Too complicated case ... */
 325                         return;
 326                 default:
 327                         /* All others are translated to HOST_UNREACH.
 328                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 329                            I believe, it is just ether pollution. --ANK
 330                          */
 331                         rel_type = ICMPV6_DEST_UNREACH;
 332                         rel_code = ICMPV6_ADDR_UNREACH;
 333                         break;
 334                 }
 335                 break;
 336         case ICMP_TIME_EXCEEDED:
 337                 if (code != ICMP_EXC_TTL)
 338                         return;
 339                 rel_type = ICMPV6_TIME_EXCEED;
 340                 rel_code = ICMPV6_EXC_HOPLIMIT;
 341                 break;
 342         }
 343
 344         /* Prepare fake skb to feed it to icmpv6_send */
 345         skb2 = skb_clone(skb, GFP_ATOMIC);
 346         if (skb2 == NULL)
 347                 return;
 348         dst_release(skb2->dst);
 349         skb2->dst = NULL;
 350         skb_pull(skb2, skb->data - (u8*)iph6);
 351         skb2->nh.raw = skb2->data;
 352
 353         /* Try to guess incoming interface */
 354         rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0);
 355         if (rt6i && rt6i->rt6i_dev) {
 356                 skb2->dev = rt6i->rt6i_dev;
 357
 358                 rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0);
 359
 360                 if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
 361                         struct ip_tunnel * t = (struct ip_tunnel*)rt6i->rt6i_dev->priv;
 362                         if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
 363                                 rel_type = ICMPV6_DEST_UNREACH;
 364                                 rel_code = ICMPV6_ADDR_UNREACH;
 365                         }
 366                         icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
 367                 }
 368         }
 369         kfree_skb(skb2);
 370         return;
 371 #endif
 372 }
 373
 374 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 375 {
 376         if (INET_ECN_is_ce(iph->tos) &&
 377             INET_ECN_is_not_ce(ip6_get_dsfield(skb->nh.ipv6h)))
 378                 IP6_ECN_set_ce(skb->nh.ipv6h);
 379 }
 380
 381 int ipip6_rcv(struct sk_buff *skb, unsigned short len)
 382 {
 383         struct iphdr *iph;
 384         struct ip_tunnel *tunnel;
 385
 386         iph = skb->nh.iph;
 387
 388         read_lock(&ipip6_lock);
 389         if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
 390                 skb->mac.raw = skb->nh.raw;
 391                 skb->nh.raw = skb_pull(skb, skb->h.raw - skb->data);
 392                 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
 393                 skb->protocol = __constant_htons(ETH_P_IPV6);
 394                 skb->ip_summed = 0;
 395                 skb->pkt_type = PACKET_HOST;
 396                 tunnel->stat.rx_packets++;
 397                 tunnel->stat.rx_bytes += skb->len;
 398                 skb->dev = tunnel->dev;
 399                 dst_release(skb->dst);
 400                 skb->dst = NULL;
 401 #ifdef CONFIG_NETFILTER
 402                 nf_conntrack_put(skb->nfct);
 403                 skb->nfct = NULL;
 404 #endif
 405                 ipip6_ecn_decapsulate(iph, skb);
 406                 netif_rx(skb);
 407                 read_unlock(&ipip6_lock);
 408                 return 0;
 409         }
 410
 411         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0);
 412         kfree_skb(skb);
 413         read_unlock(&ipip6_lock);
 414         return 0;
 415 }
 416
 417 /* Need this wrapper because NF_HOOK takes the function address */
 418 static inline int do_ip_send(struct sk_buff *skb)
 419 {
 420         return ip_send(skb);
 421 }
 422
 423 /*
 424  *      This function assumes it is being called from dev_queue_xmit()
 425  *      and that skb is filled properly by that function.
 426  */
 427
 428 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 429 {
 430         struct ip_tunnel *tunnel = (struct ip_tunnel*)dev->priv;
 431         struct net_device_stats *stats = &tunnel->stat;
 432         struct iphdr  *tiph = &tunnel->parms.iph;
 433         struct ipv6hdr *iph6 = skb->nh.ipv6h;
 434         u8     tos = tunnel->parms.iph.tos;
 435         struct rtable *rt;                      /* Route to the other host */
 436         struct net_device *tdev;                        /* Device to other host */
 437         struct iphdr  *iph;                     /* Our new IP header */
 438         int    max_headroom;                    /* The extra header space needed */
 439         u32    dst = tiph->daddr;
 440         int    mtu;
 441         struct in6_addr *addr6;
 442         int addr_type;
 443
 444         if (tunnel->recursion++) {
 445                 tunnel->stat.collisions++;
 446                 goto tx_error;
 447         }
 448
 449         if (skb->protocol != __constant_htons(ETH_P_IPV6))
 450                 goto tx_error;
 451
 452         if (!dst) {
 453                 struct neighbour *neigh = NULL;
 454
 455                 if (skb->dst)
 456                         neigh = skb->dst->neighbour;
 457
 458                 if (neigh == NULL) {
 459                         printk(KERN_DEBUG "sit: nexthop == NULL\n");
 460                         goto tx_error;
 461                 }
 462
 463                 addr6 = (struct in6_addr*)&neigh->primary_key;
 464                 addr_type = ipv6_addr_type(addr6);
 465
 466                 if (addr_type == IPV6_ADDR_ANY) {
 467                         addr6 = &skb->nh.ipv6h->daddr;
 468                         addr_type = ipv6_addr_type(addr6);
 469                 }
 470
 471                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 472                         goto tx_error_icmp;
 473
 474                 dst = addr6->s6_addr32[3];
 475         }
 476
 477         if (ip_route_output(&rt, dst, tiph->saddr, RT_TOS(tos), tunnel->parms.link)) {
 478                 tunnel->stat.tx_carrier_errors++;
 479                 goto tx_error_icmp;
 480         }
 481         tdev = rt->u.dst.dev;
 482
 483         if (tdev == dev) {
 484                 ip_rt_put(rt);
 485                 tunnel->stat.collisions++;
 486                 goto tx_error;
 487         }
 488
 489         mtu = rt->u.dst.pmtu - sizeof(struct iphdr);
 490         if (mtu < 68) {
 491                 tunnel->stat.collisions++;
 492                 ip_rt_put(rt);
 493                 goto tx_error;
 494         }
 495         if (mtu < IPV6_MIN_MTU)
 496                 mtu = IPV6_MIN_MTU;
 497         if (skb->dst && mtu < skb->dst->pmtu) {
 498                 struct rt6_info *rt6 = (struct rt6_info*)skb->dst;
 499                 if (mtu < rt6->u.dst.pmtu) {
 500                         if (tunnel->parms.iph.daddr || rt6->rt6i_dst.plen == 128) {
 501                                 rt6->rt6i_flags |= RTF_MODIFIED;
 502                                 rt6->u.dst.pmtu = mtu;
 503                         }
 504                 }
 505         }
 506         if (skb->len > mtu) {
 507                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 508                 ip_rt_put(rt);
 509                 goto tx_error;
 510         }
 511
 512         if (tunnel->err_count > 0) {
 513                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
 514                         tunnel->err_count--;
 515                         dst_link_failure(skb);
 516                 } else
 517                         tunnel->err_count = 0;
 518         }
 519
 520         skb->h.raw = skb->nh.raw;
 521
 522         /*
 523          * Okay, now see if we can stuff it in the buffer as-is.
 524          */
 525         max_headroom = (((tdev->hard_header_len+15)&~15)+sizeof(struct iphdr));
 526
 527         if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) {
 528                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 529                 if (!new_skb) {
 530                         ip_rt_put(rt);
 531                         stats->tx_dropped++;
 532                         dev_kfree_skb(skb);
 533                         tunnel->recursion--;
 534                         return 0;
 535                 }
 536                 if (skb->sk)
 537                         skb_set_owner_w(new_skb, skb->sk);
 538                 dev_kfree_skb(skb);
 539                 skb = new_skb;
 540         }
 541
 542         skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
 543         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 544         dst_release(skb->dst);
 545         skb->dst = &rt->u.dst;
 546
 547         /*
 548          *      Push down and install the IPIP header.
 549          */
 550
 551         iph                     =       skb->nh.iph;
 552         iph->version            =       4;
 553         iph->ihl                =       sizeof(struct iphdr)>>2;
 554         if (mtu > IPV6_MIN_MTU)
 555                 iph->frag_off   =       __constant_htons(IP_DF);
 556         else
 557                 iph->frag_off   =       0;
 558
 559         iph->protocol           =       IPPROTO_IPV6;
 560         iph->tos                =       INET_ECN_encapsulate(tos, ip6_get_dsfield(iph6));
 561         iph->daddr              =       rt->rt_dst;
 562         iph->saddr              =       rt->rt_src;
 563
 564         if ((iph->ttl = tiph->ttl) == 0)
 565                 iph->ttl        =       iph6->hop_limit;
 566
 567 #ifdef CONFIG_NETFILTER
 568         nf_conntrack_put(skb->nfct);
 569         skb->nfct = NULL;
 570 #endif
 571
 572         IPTUNNEL_XMIT();
 573         tunnel->recursion--;
 574         return 0;
 575
 576 tx_error_icmp:
 577         dst_link_failure(skb);
 578 tx_error:
 579         stats->tx_errors++;
 580         dev_kfree_skb(skb);
 581         tunnel->recursion--;
 582         return 0;
 583 }
 584
 585 static int
 586 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 587 {
 588         int err = 0;
 589         struct ip_tunnel_parm p;
 590         struct ip_tunnel *t;
 591
 592         MOD_INC_USE_COUNT;
 593
 594         switch (cmd) {
 595         case SIOCGETTUNNEL:
 596                 t = NULL;
 597                 if (dev == &ipip6_fb_tunnel_dev) {
 598                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 599                                 err = -EFAULT;
 600                                 break;
 601                         }
 602                         t = ipip6_tunnel_locate(&p, 0);
 603                 }
 604                 if (t == NULL)
 605                         t = (struct ip_tunnel*)dev->priv;
 606                 memcpy(&p, &t->parms, sizeof(p));
 607                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 608                         err = -EFAULT;
 609                 break;
 610
 611         case SIOCADDTUNNEL:
 612         case SIOCCHGTUNNEL:
 613                 err = -EPERM;
 614                 if (!capable(CAP_NET_ADMIN))
 615                         goto done;
 616
 617                 err = -EFAULT;
 618                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 619                         goto done;
 620
 621                 err = -EINVAL;
 622                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 623                     p.iph.ihl != 5 || (p.iph.frag_off&__constant_htons(~IP_DF)))
 624                         goto done;
 625                 if (p.iph.ttl)
 626                         p.iph.frag_off |= __constant_htons(IP_DF);
 627
 628                 t = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL);
 629
 630                 if (dev != &ipip6_fb_tunnel_dev && cmd == SIOCCHGTUNNEL &&
 631                     t != &ipip6_fb_tunnel) {
 632                         if (t != NULL) {
 633                                 if (t->dev != dev) {
 634                                         err = -EEXIST;
 635                                         break;
 636                                 }
 637                         } else {
 638                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 639                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 640                                         err = -EINVAL;
 641                                         break;
 642                                 }
 643                                 t = (struct ip_tunnel*)dev->priv;
 644                                 ipip6_tunnel_unlink(t);
 645                                 t->parms.iph.saddr = p.iph.saddr;
 646                                 t->parms.iph.daddr = p.iph.daddr;
 647                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 648                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 649                                 ipip6_tunnel_link(t);
 650                                 netdev_state_change(dev);
 651                         }
 652                 }
 653
 654                 if (t) {
 655                         err = 0;
 656                         if (cmd == SIOCCHGTUNNEL) {
 657                                 t->parms.iph.ttl = p.iph.ttl;
 658                                 t->parms.iph.tos = p.iph.tos;
 659                         }
 660                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 661                                 err = -EFAULT;
 662                 } else
 663                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 664                 break;
 665
 666         case SIOCDELTUNNEL:
 667                 err = -EPERM;
 668                 if (!capable(CAP_NET_ADMIN))
 669                         goto done;
 670
 671                 if (dev == &ipip6_fb_tunnel_dev) {
 672                         err = -EFAULT;
 673                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 674                                 goto done;
 675                         err = -ENOENT;
 676                         if ((t = ipip6_tunnel_locate(&p, 0)) == NULL)
 677                                 goto done;
 678                         err = -EPERM;
 679                         if (t == &ipip6_fb_tunnel)
 680                                 goto done;
 681                 }
 682                 err = unregister_netdevice(dev);
 683                 break;
 684
 685         default:
 686                 err = -EINVAL;
 687         }
 688
 689 done:
 690         MOD_DEC_USE_COUNT;
 691         return err;
 692 }
 693
 694 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev)
 695 {
 696         return &(((struct ip_tunnel*)dev->priv)->stat);
 697 }
 698
 699 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 700 {
 701         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 702                 return -EINVAL;
 703         dev->mtu = new_mtu;
 704         return 0;
 705 }
 706
 707 static void ipip6_tunnel_init_gen(struct net_device *dev)
 708 {
 709         struct ip_tunnel *t = (struct ip_tunnel*)dev->priv;
 710
 711         dev->destructor         = ipip6_tunnel_destructor;
 712         dev->uninit             = ipip6_tunnel_uninit;
 713         dev->hard_start_xmit    = ipip6_tunnel_xmit;
 714         dev->get_stats          = ipip6_tunnel_get_stats;
 715         dev->do_ioctl           = ipip6_tunnel_ioctl;
 716         dev->change_mtu         = ipip6_tunnel_change_mtu;
 717
 718         dev_init_buffers(dev);
 719
 720         dev->type               = ARPHRD_SIT;
 721         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 722         dev->mtu                = 1500 - sizeof(struct iphdr);
 723         dev->flags              = IFF_NOARP;
 724         dev->iflink             = 0;
 725         dev->addr_len           = 4;
 726         memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 727         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 728 }
 729
 730 static int ipip6_tunnel_init(struct net_device *dev)
 731 {
 732         struct net_device *tdev = NULL;
 733         struct ip_tunnel *tunnel;
 734         struct iphdr *iph;
 735
 736         tunnel = (struct ip_tunnel*)dev->priv;
 737         iph = &tunnel->parms.iph;
 738
 739         ipip6_tunnel_init_gen(dev);
 740
 741         if (iph->daddr) {
 742                 struct rtable *rt;
 743                 if (!ip_route_output(&rt, iph->daddr, iph->saddr, RT_TOS(iph->tos), tunnel->parms.link)) {
 744                         tdev = rt->u.dst.dev;
 745                         ip_rt_put(rt);
 746                 }
 747                 dev->flags |= IFF_POINTOPOINT;
 748         }
 749
 750         if (!tdev && tunnel->parms.link)
 751                 tdev = __dev_get_by_index(tunnel->parms.link);
 752
 753         if (tdev) {
 754                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 755                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 756                 if (dev->mtu < IPV6_MIN_MTU)
 757                         dev->mtu = IPV6_MIN_MTU;
 758         }
 759         dev->iflink = tunnel->parms.link;
 760
 761         return 0;
 762 }
 763
 764 #ifdef MODULE
 765 static int ipip6_fb_tunnel_open(struct net_device *dev)
 766 {
 767         MOD_INC_USE_COUNT;
 768         return 0;
 769 }
 770
 771 static int ipip6_fb_tunnel_close(struct net_device *dev)
 772 {
 773         MOD_DEC_USE_COUNT;
 774         return 0;
 775 }
 776 #endif
 777
 778 int __init ipip6_fb_tunnel_init(struct net_device *dev)
 779 {
 780         struct iphdr *iph;
 781
 782         ipip6_tunnel_init_gen(dev);
 783 #ifdef MODULE
 784         dev->open               = ipip6_fb_tunnel_open;
 785         dev->stop               = ipip6_fb_tunnel_close;
 786 #endif
 787
 788         iph = &ipip6_fb_tunnel.parms.iph;
 789         iph->version            = 4;
 790         iph->protocol           = IPPROTO_IPV6;
 791         iph->ihl                = 5;
 792         iph->ttl                = 64;
 793
 794         dev_hold(dev);
 795         tunnels_wc[0]           = &ipip6_fb_tunnel;
 796         return 0;
 797 }
 798
 799 static struct inet_protocol sit_protocol = {
 800         ipip6_rcv,
 801         ipip6_err,
 802         0,
 803         IPPROTO_IPV6,
 804         0,
 805         NULL,
 806         "IPv6"
 807 };
 808
 809 #ifdef MODULE
 810 void sit_cleanup(void)
 811 {
 812         inet_del_protocol(&sit_protocol);
 813         unregister_netdevice(&ipip6_fb_tunnel_dev);
 814 }
 815 #endif
 816
 817 int __init sit_init(void)
 818 {
 819         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
 820
 821         ipip6_fb_tunnel_dev.priv = (void*)&ipip6_fb_tunnel;
 822         strcpy(ipip6_fb_tunnel_dev.name, ipip6_fb_tunnel.parms.name);
 823 #ifdef MODULE
 824         register_netdev(&ipip6_fb_tunnel_dev);
 825 #else
 826         register_netdevice(&ipip6_fb_tunnel_dev);
 827 #endif
 828         inet_add_protocol(&sit_protocol);
 829         return 0;
 830 }