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  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  20  */
  21
  22 #include <linux/module.h>
  23 #include <linux/capability.h>
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/net.h>
  29 #include <linux/in6.h>
  30 #include <linux/netdevice.h>
  31 #include <linux/if_arp.h>
  32 #include <linux/icmp.h>
  33 #include <asm/uaccess.h>
  34 #include <linux/init.h>
  35 #include <linux/netfilter_ipv4.h>
  36 #include <linux/if_ether.h>
  37
  38 #include <net/sock.h>
  39 #include <net/snmp.h>
  40
  41 #include <net/ipv6.h>
  42 #include <net/protocol.h>
  43 #include <net/transp_v6.h>
  44 #include <net/ip6_fib.h>
  45 #include <net/ip6_route.h>
  46 #include <net/ndisc.h>
  47 #include <net/addrconf.h>
  48 #include <net/ip.h>
  49 #include <net/udp.h>
  50 #include <net/icmp.h>
  51 #include <net/ipip.h>
  52 #include <net/inet_ecn.h>
  53 #include <net/xfrm.h>
  54 #include <net/dsfield.h>
  55 #include <net/net_namespace.h>
  56 #include <net/netns/generic.h>
  57
  58 /*
  59    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  60
  61    For comments look at net/ipv4/ip_gre.c --ANK
  62  */
  63
  64 #define HASH_SIZE  16
  65 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  66
  67 static int ipip6_fb_tunnel_init(struct net_device *dev);
  68 static int ipip6_tunnel_init(struct net_device *dev);
  69 static void ipip6_tunnel_setup(struct net_device *dev);
  70
  71 static int sit_net_id;
  72 struct sit_net {
  73         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  74         struct ip_tunnel *tunnels_r[HASH_SIZE];
  75         struct ip_tunnel *tunnels_l[HASH_SIZE];
  76         struct ip_tunnel *tunnels_wc[1];
  77         struct ip_tunnel **tunnels[4];
  78
  79         struct net_device *fb_tunnel_dev;
  80 };
  81
  82 static DEFINE_RWLOCK(ipip6_lock);
  83
  84 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
  85                 __be32 remote, __be32 local)
  86 {
  87         unsigned h0 = HASH(remote);
  88         unsigned h1 = HASH(local);
  89         struct ip_tunnel *t;
  90         struct sit_net *sitn = net_generic(net, sit_net_id);
  91
  92         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
  93                 if (local == t->parms.iph.saddr &&
  94                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  95                         return t;
  96         }
  97         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
  98                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
  99                         return t;
 100         }
 101         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
 102                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
 103                         return t;
 104         }
 105         if ((t = sitn->tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
 106                 return t;
 107         return NULL;
 108 }
 109
 110 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
 111                 struct ip_tunnel_parm *parms)
 112 {
 113         __be32 remote = parms->iph.daddr;
 114         __be32 local = parms->iph.saddr;
 115         unsigned h = 0;
 116         int prio = 0;
 117
 118         if (remote) {
 119                 prio |= 2;
 120                 h ^= HASH(remote);
 121         }
 122         if (local) {
 123                 prio |= 1;
 124                 h ^= HASH(local);
 125         }
 126         return &sitn->tunnels[prio][h];
 127 }
 128
 129 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
 130                 struct ip_tunnel *t)
 131 {
 132         return __ipip6_bucket(sitn, &t->parms);
 133 }
 134
 135 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 136 {
 137         struct ip_tunnel **tp;
 138
 139         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
 140                 if (t == *tp) {
 141                         write_lock_bh(&ipip6_lock);
 142                         *tp = t->next;
 143                         write_unlock_bh(&ipip6_lock);
 144                         break;
 145                 }
 146         }
 147 }
 148
 149 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 150 {
 151         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 152
 153         t->next = *tp;
 154         write_lock_bh(&ipip6_lock);
 155         *tp = t;
 156         write_unlock_bh(&ipip6_lock);
 157 }
 158
 159 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 160                 struct ip_tunnel_parm *parms, int create)
 161 {
 162         __be32 remote = parms->iph.daddr;
 163         __be32 local = parms->iph.saddr;
 164         struct ip_tunnel *t, **tp, *nt;
 165         struct net_device *dev;
 166         char name[IFNAMSIZ];
 167         struct sit_net *sitn = net_generic(net, sit_net_id);
 168
 169         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
 170                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
 171                         return t;
 172         }
 173         if (!create)
 174                 goto failed;
 175
 176         if (parms->name[0])
 177                 strlcpy(name, parms->name, IFNAMSIZ);
 178         else
 179                 sprintf(name, "sit%%d");
 180
 181         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 182         if (dev == NULL)
 183                 return NULL;
 184
 185         dev_net_set(dev, net);
 186
 187         if (strchr(name, '%')) {
 188                 if (dev_alloc_name(dev, name) < 0)
 189                         goto failed_free;
 190         }
 191
 192         nt = netdev_priv(dev);
 193         dev->init = ipip6_tunnel_init;
 194         nt->parms = *parms;
 195
 196         if (parms->i_flags & SIT_ISATAP)
 197                 dev->priv_flags |= IFF_ISATAP;
 198
 199         if (register_netdevice(dev) < 0)
 200                 goto failed_free;
 201
 202         dev_hold(dev);
 203
 204         ipip6_tunnel_link(sitn, nt);
 205         return nt;
 206
 207 failed_free:
 208         free_netdev(dev);
 209 failed:
 210         return NULL;
 211 }
 212
 213 static struct ip_tunnel_prl_entry *
 214 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 215 {
 216         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
 217
 218         for (p = t->prl; p; p = p->next)
 219                 if (p->addr == addr)
 220                         break;
 221         return p;
 222
 223 }
 224
 225 static int ipip6_tunnel_get_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 226 {
 227         struct ip_tunnel_prl *kp;
 228         struct ip_tunnel_prl_entry *prl;
 229         unsigned int cmax, c = 0, ca, len;
 230         int ret = 0;
 231
 232         cmax = a->datalen / sizeof(*a);
 233         if (cmax > 1 && a->addr != htonl(INADDR_ANY))
 234                 cmax = 1;
 235
 236         /* For simple GET or for root users,
 237          * we try harder to allocate.
 238          */
 239         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 240                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 241                 NULL;
 242
 243         read_lock(&ipip6_lock);
 244
 245         ca = t->prl_count < cmax ? t->prl_count : cmax;
 246
 247         if (!kp) {
 248                 /* We don't try hard to allocate much memory for
 249                  * non-root users.
 250                  * For root users, retry allocating enough memory for
 251                  * the answer.
 252                  */
 253                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 254                 if (!kp) {
 255                         ret = -ENOMEM;
 256                         goto out;
 257                 }
 258         }
 259
 260         c = 0;
 261         for (prl = t->prl; prl; prl = prl->next) {
 262                 if (c > cmax)
 263                         break;
 264                 if (a->addr != htonl(INADDR_ANY) && prl->addr != a->addr)
 265                         continue;
 266                 kp[c].addr = prl->addr;
 267                 kp[c].flags = prl->flags;
 268                 c++;
 269                 if (a->addr != htonl(INADDR_ANY))
 270                         break;
 271         }
 272 out:
 273         read_unlock(&ipip6_lock);
 274
 275         len = sizeof(*kp) * c;
 276         ret = len ? copy_to_user(a->data, kp, len) : 0;
 277
 278         kfree(kp);
 279         if (ret)
 280                 return -EFAULT;
 281
 282         a->datalen = len;
 283         return 0;
 284 }
 285
 286 static int
 287 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 288 {
 289         struct ip_tunnel_prl_entry *p;
 290         int err = 0;
 291
 292         if (a->addr == htonl(INADDR_ANY))
 293                 return -EINVAL;
 294
 295         write_lock(&ipip6_lock);
 296
 297         for (p = t->prl; p; p = p->next) {
 298                 if (p->addr == a->addr) {
 299                         if (chg)
 300                                 goto update;
 301                         err = -EEXIST;
 302                         goto out;
 303                 }
 304         }
 305
 306         if (chg) {
 307                 err = -ENXIO;
 308                 goto out;
 309         }
 310
 311         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 312         if (!p) {
 313                 err = -ENOBUFS;
 314                 goto out;
 315         }
 316
 317         p->next = t->prl;
 318         t->prl = p;
 319         t->prl_count++;
 320 update:
 321         p->addr = a->addr;
 322         p->flags = a->flags;
 323 out:
 324         write_unlock(&ipip6_lock);
 325         return err;
 326 }
 327
 328 static int
 329 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 330 {
 331         struct ip_tunnel_prl_entry *x, **p;
 332         int err = 0;
 333
 334         write_lock(&ipip6_lock);
 335
 336         if (a && a->addr != htonl(INADDR_ANY)) {
 337                 for (p = &t->prl; *p; p = &(*p)->next) {
 338                         if ((*p)->addr == a->addr) {
 339                                 x = *p;
 340                                 *p = x->next;
 341                                 kfree(x);
 342                                 t->prl_count--;
 343                                 goto out;
 344                         }
 345                 }
 346                 err = -ENXIO;
 347         } else {
 348                 while (t->prl) {
 349                         x = t->prl;
 350                         t->prl = t->prl->next;
 351                         kfree(x);
 352                         t->prl_count--;
 353                 }
 354         }
 355 out:
 356         write_unlock(&ipip6_lock);
 357         return 0;
 358 }
 359
 360 static int
 361 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 362 {
 363         struct ip_tunnel_prl_entry *p;
 364         int ok = 1;
 365
 366         read_lock(&ipip6_lock);
 367         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 368         if (p) {
 369                 if (p->flags & PRL_DEFAULT)
 370                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 371                 else
 372                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 373         } else {
 374                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 375                 if (ipv6_addr_is_isatap(addr6) &&
 376                     (addr6->s6_addr32[3] == iph->saddr) &&
 377                     ipv6_chk_prefix(addr6, t->dev))
 378                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 379                 else
 380                         ok = 0;
 381         }
 382         read_unlock(&ipip6_lock);
 383         return ok;
 384 }
 385
 386 static void ipip6_tunnel_uninit(struct net_device *dev)
 387 {
 388         struct net *net = dev_net(dev);
 389         struct sit_net *sitn = net_generic(net, sit_net_id);
 390
 391         if (dev == sitn->fb_tunnel_dev) {
 392                 write_lock_bh(&ipip6_lock);
 393                 sitn->tunnels_wc[0] = NULL;
 394                 write_unlock_bh(&ipip6_lock);
 395                 dev_put(dev);
 396         } else {
 397                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 398                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 399                 dev_put(dev);
 400         }
 401 }
 402
 403
 404 static int ipip6_err(struct sk_buff *skb, u32 info)
 405 {
 406 #ifndef I_WISH_WORLD_WERE_PERFECT
 407
 408 /* It is not :-( All the routers (except for Linux) return only
 409    8 bytes of packet payload. It means, that precise relaying of
 410    ICMP in the real Internet is absolutely infeasible.
 411  */
 412         struct iphdr *iph = (struct iphdr*)skb->data;
 413         const int type = icmp_hdr(skb)->type;
 414         const int code = icmp_hdr(skb)->code;
 415         struct ip_tunnel *t;
 416         int err;
 417
 418         switch (type) {
 419         default:
 420         case ICMP_PARAMETERPROB:
 421                 return 0;
 422
 423         case ICMP_DEST_UNREACH:
 424                 switch (code) {
 425                 case ICMP_SR_FAILED:
 426                 case ICMP_PORT_UNREACH:
 427                         /* Impossible event. */
 428                         return 0;
 429                 case ICMP_FRAG_NEEDED:
 430                         /* Soft state for pmtu is maintained by IP core. */
 431                         return 0;
 432                 default:
 433                         /* All others are translated to HOST_UNREACH.
 434                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 435                            I believe they are just ether pollution. --ANK
 436                          */
 437                         break;
 438                 }
 439                 break;
 440         case ICMP_TIME_EXCEEDED:
 441                 if (code != ICMP_EXC_TTL)
 442                         return 0;
 443                 break;
 444         }
 445
 446         err = -ENOENT;
 447
 448         read_lock(&ipip6_lock);
 449         t = ipip6_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
 450         if (t == NULL || t->parms.iph.daddr == 0)
 451                 goto out;
 452
 453         err = 0;
 454         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 455                 goto out;
 456
 457         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
 458                 t->err_count++;
 459         else
 460                 t->err_count = 1;
 461         t->err_time = jiffies;
 462 out:
 463         read_unlock(&ipip6_lock);
 464         return err;
 465 #else
 466         struct iphdr *iph = (struct iphdr*)dp;
 467         int hlen = iph->ihl<<2;
 468         struct ipv6hdr *iph6;
 469         const int type = icmp_hdr(skb)->type;
 470         const int code = icmp_hdr(skb)->code;
 471         int rel_type = 0;
 472         int rel_code = 0;
 473         int rel_info = 0;
 474         struct sk_buff *skb2;
 475         struct rt6_info *rt6i;
 476
 477         if (len < hlen + sizeof(struct ipv6hdr))
 478                 return;
 479         iph6 = (struct ipv6hdr*)(dp + hlen);
 480
 481         switch (type) {
 482         default:
 483                 return;
 484         case ICMP_PARAMETERPROB:
 485                 if (icmp_hdr(skb)->un.gateway < hlen)
 486                         return;
 487
 488                 /* So... This guy found something strange INSIDE encapsulated
 489                    packet. Well, he is fool, but what can we do ?
 490                  */
 491                 rel_type = ICMPV6_PARAMPROB;
 492                 rel_info = icmp_hdr(skb)->un.gateway - hlen;
 493                 break;
 494
 495         case ICMP_DEST_UNREACH:
 496                 switch (code) {
 497                 case ICMP_SR_FAILED:
 498                 case ICMP_PORT_UNREACH:
 499                         /* Impossible event. */
 500                         return;
 501                 case ICMP_FRAG_NEEDED:
 502                         /* Too complicated case ... */
 503                         return;
 504                 default:
 505                         /* All others are translated to HOST_UNREACH.
 506                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 507                            I believe, it is just ether pollution. --ANK
 508                          */
 509                         rel_type = ICMPV6_DEST_UNREACH;
 510                         rel_code = ICMPV6_ADDR_UNREACH;
 511                         break;
 512                 }
 513                 break;
 514         case ICMP_TIME_EXCEEDED:
 515                 if (code != ICMP_EXC_TTL)
 516                         return;
 517                 rel_type = ICMPV6_TIME_EXCEED;
 518                 rel_code = ICMPV6_EXC_HOPLIMIT;
 519                 break;
 520         }
 521
 522         /* Prepare fake skb to feed it to icmpv6_send */
 523         skb2 = skb_clone(skb, GFP_ATOMIC);
 524         if (skb2 == NULL)
 525                 return 0;
 526         dst_release(skb2->dst);
 527         skb2->dst = NULL;
 528         skb_pull(skb2, skb->data - (u8*)iph6);
 529         skb_reset_network_header(skb2);
 530
 531         /* Try to guess incoming interface */
 532         rt6i = rt6_lookup(dev_net(skb->dev), &iph6->saddr, NULL, NULL, 0);
 533         if (rt6i && rt6i->rt6i_dev) {
 534                 skb2->dev = rt6i->rt6i_dev;
 535
 536                 rt6i = rt6_lookup(dev_net(skb->dev),
 537                                 &iph6->daddr, &iph6->saddr, NULL, 0);
 538
 539                 if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
 540                         struct ip_tunnel *t = netdev_priv(rt6i->rt6i_dev);
 541                         if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
 542                                 rel_type = ICMPV6_DEST_UNREACH;
 543                                 rel_code = ICMPV6_ADDR_UNREACH;
 544                         }
 545                         icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
 546                 }
 547         }
 548         kfree_skb(skb2);
 549         return 0;
 550 #endif
 551 }
 552
 553 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 554 {
 555         if (INET_ECN_is_ce(iph->tos))
 556                 IP6_ECN_set_ce(ipv6_hdr(skb));
 557 }
 558
 559 static int ipip6_rcv(struct sk_buff *skb)
 560 {
 561         struct iphdr *iph;
 562         struct ip_tunnel *tunnel;
 563
 564         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 565                 goto out;
 566
 567         iph = ip_hdr(skb);
 568
 569         read_lock(&ipip6_lock);
 570         if ((tunnel = ipip6_tunnel_lookup(dev_net(skb->dev),
 571                                         iph->saddr, iph->daddr)) != NULL) {
 572                 secpath_reset(skb);
 573                 skb->mac_header = skb->network_header;
 574                 skb_reset_network_header(skb);
 575                 IPCB(skb)->flags = 0;
 576                 skb->protocol = htons(ETH_P_IPV6);
 577                 skb->pkt_type = PACKET_HOST;
 578
 579                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 580                     !isatap_chksrc(skb, iph, tunnel)) {
 581                         tunnel->stat.rx_errors++;
 582                         read_unlock(&ipip6_lock);
 583                         kfree_skb(skb);
 584                         return 0;
 585                 }
 586                 tunnel->stat.rx_packets++;
 587                 tunnel->stat.rx_bytes += skb->len;
 588                 skb->dev = tunnel->dev;
 589                 dst_release(skb->dst);
 590                 skb->dst = NULL;
 591                 nf_reset(skb);
 592                 ipip6_ecn_decapsulate(iph, skb);
 593                 netif_rx(skb);
 594                 read_unlock(&ipip6_lock);
 595                 return 0;
 596         }
 597
 598         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 599         kfree_skb(skb);
 600         read_unlock(&ipip6_lock);
 601 out:
 602         return 0;
 603 }
 604
 605 /* Returns the embedded IPv4 address if the IPv6 address
 606    comes from 6to4 (RFC 3056) addr space */
 607
 608 static inline __be32 try_6to4(struct in6_addr *v6dst)
 609 {
 610         __be32 dst = 0;
 611
 612         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 613                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 614                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 615         }
 616         return dst;
 617 }
 618
 619 /*
 620  *      This function assumes it is being called from dev_queue_xmit()
 621  *      and that skb is filled properly by that function.
 622  */
 623
 624 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 625 {
 626         struct ip_tunnel *tunnel = netdev_priv(dev);
 627         struct net_device_stats *stats = &tunnel->stat;
 628         struct iphdr  *tiph = &tunnel->parms.iph;
 629         struct ipv6hdr *iph6 = ipv6_hdr(skb);
 630         u8     tos = tunnel->parms.iph.tos;
 631         struct rtable *rt;                      /* Route to the other host */
 632         struct net_device *tdev;                        /* Device to other host */
 633         struct iphdr  *iph;                     /* Our new IP header */
 634         unsigned int max_headroom;              /* The extra header space needed */
 635         __be32 dst = tiph->daddr;
 636         int    mtu;
 637         struct in6_addr *addr6;
 638         int addr_type;
 639
 640         if (tunnel->recursion++) {
 641                 tunnel->stat.collisions++;
 642                 goto tx_error;
 643         }
 644
 645         if (skb->protocol != htons(ETH_P_IPV6))
 646                 goto tx_error;
 647
 648         /* ISATAP (RFC4214) - must come before 6to4 */
 649         if (dev->priv_flags & IFF_ISATAP) {
 650                 struct neighbour *neigh = NULL;
 651
 652                 if (skb->dst)
 653                         neigh = skb->dst->neighbour;
 654
 655                 if (neigh == NULL) {
 656                         if (net_ratelimit())
 657                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 658                         goto tx_error;
 659                 }
 660
 661                 addr6 = (struct in6_addr*)&neigh->primary_key;
 662                 addr_type = ipv6_addr_type(addr6);
 663
 664                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 665                      ipv6_addr_is_isatap(addr6))
 666                         dst = addr6->s6_addr32[3];
 667                 else
 668                         goto tx_error;
 669         }
 670
 671         if (!dst)
 672                 dst = try_6to4(&iph6->daddr);
 673
 674         if (!dst) {
 675                 struct neighbour *neigh = NULL;
 676
 677                 if (skb->dst)
 678                         neigh = skb->dst->neighbour;
 679
 680                 if (neigh == NULL) {
 681                         if (net_ratelimit())
 682                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 683                         goto tx_error;
 684                 }
 685
 686                 addr6 = (struct in6_addr*)&neigh->primary_key;
 687                 addr_type = ipv6_addr_type(addr6);
 688
 689                 if (addr_type == IPV6_ADDR_ANY) {
 690                         addr6 = &ipv6_hdr(skb)->daddr;
 691                         addr_type = ipv6_addr_type(addr6);
 692                 }
 693
 694                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 695                         goto tx_error_icmp;
 696
 697                 dst = addr6->s6_addr32[3];
 698         }
 699
 700         {
 701                 struct flowi fl = { .nl_u = { .ip4_u =
 702                                               { .daddr = dst,
 703                                                 .saddr = tiph->saddr,
 704                                                 .tos = RT_TOS(tos) } },
 705                                     .oif = tunnel->parms.link,
 706                                     .proto = IPPROTO_IPV6 };
 707                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 708                         tunnel->stat.tx_carrier_errors++;
 709                         goto tx_error_icmp;
 710                 }
 711         }
 712         if (rt->rt_type != RTN_UNICAST) {
 713                 ip_rt_put(rt);
 714                 tunnel->stat.tx_carrier_errors++;
 715                 goto tx_error_icmp;
 716         }
 717         tdev = rt->u.dst.dev;
 718
 719         if (tdev == dev) {
 720                 ip_rt_put(rt);
 721                 tunnel->stat.collisions++;
 722                 goto tx_error;
 723         }
 724
 725         if (tiph->frag_off)
 726                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 727         else
 728                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
 729
 730         if (mtu < 68) {
 731                 tunnel->stat.collisions++;
 732                 ip_rt_put(rt);
 733                 goto tx_error;
 734         }
 735         if (mtu < IPV6_MIN_MTU)
 736                 mtu = IPV6_MIN_MTU;
 737         if (tunnel->parms.iph.daddr && skb->dst)
 738                 skb->dst->ops->update_pmtu(skb->dst, mtu);
 739
 740         if (skb->len > mtu) {
 741                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 742                 ip_rt_put(rt);
 743                 goto tx_error;
 744         }
 745
 746         if (tunnel->err_count > 0) {
 747                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
 748                         tunnel->err_count--;
 749                         dst_link_failure(skb);
 750                 } else
 751                         tunnel->err_count = 0;
 752         }
 753
 754         /*
 755          * Okay, now see if we can stuff it in the buffer as-is.
 756          */
 757         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 758
 759         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 760             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 761                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 762                 if (!new_skb) {
 763                         ip_rt_put(rt);
 764                         stats->tx_dropped++;
 765                         dev_kfree_skb(skb);
 766                         tunnel->recursion--;
 767                         return 0;
 768                 }
 769                 if (skb->sk)
 770                         skb_set_owner_w(new_skb, skb->sk);
 771                 dev_kfree_skb(skb);
 772                 skb = new_skb;
 773                 iph6 = ipv6_hdr(skb);
 774         }
 775
 776         skb->transport_header = skb->network_header;
 777         skb_push(skb, sizeof(struct iphdr));
 778         skb_reset_network_header(skb);
 779         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 780         IPCB(skb)->flags = 0;
 781         dst_release(skb->dst);
 782         skb->dst = &rt->u.dst;
 783
 784         /*
 785          *      Push down and install the IPIP header.
 786          */
 787
 788         iph                     =       ip_hdr(skb);
 789         iph->version            =       4;
 790         iph->ihl                =       sizeof(struct iphdr)>>2;
 791         if (mtu > IPV6_MIN_MTU)
 792                 iph->frag_off   =       htons(IP_DF);
 793         else
 794                 iph->frag_off   =       0;
 795
 796         iph->protocol           =       IPPROTO_IPV6;
 797         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 798         iph->daddr              =       rt->rt_dst;
 799         iph->saddr              =       rt->rt_src;
 800
 801         if ((iph->ttl = tiph->ttl) == 0)
 802                 iph->ttl        =       iph6->hop_limit;
 803
 804         nf_reset(skb);
 805
 806         IPTUNNEL_XMIT();
 807         tunnel->recursion--;
 808         return 0;
 809
 810 tx_error_icmp:
 811         dst_link_failure(skb);
 812 tx_error:
 813         stats->tx_errors++;
 814         dev_kfree_skb(skb);
 815         tunnel->recursion--;
 816         return 0;
 817 }
 818
 819 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 820 {
 821         struct net_device *tdev = NULL;
 822         struct ip_tunnel *tunnel;
 823         struct iphdr *iph;
 824
 825         tunnel = netdev_priv(dev);
 826         iph = &tunnel->parms.iph;
 827
 828         if (iph->daddr) {
 829                 struct flowi fl = { .nl_u = { .ip4_u =
 830                                               { .daddr = iph->daddr,
 831                                                 .saddr = iph->saddr,
 832                                                 .tos = RT_TOS(iph->tos) } },
 833                                     .oif = tunnel->parms.link,
 834                                     .proto = IPPROTO_IPV6 };
 835                 struct rtable *rt;
 836                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 837                         tdev = rt->u.dst.dev;
 838                         ip_rt_put(rt);
 839                 }
 840                 dev->flags |= IFF_POINTOPOINT;
 841         }
 842
 843         if (!tdev && tunnel->parms.link)
 844                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 845
 846         if (tdev) {
 847                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 848                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 849                 if (dev->mtu < IPV6_MIN_MTU)
 850                         dev->mtu = IPV6_MIN_MTU;
 851         }
 852         dev->iflink = tunnel->parms.link;
 853 }
 854
 855 static int
 856 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 857 {
 858         int err = 0;
 859         struct ip_tunnel_parm p;
 860         struct ip_tunnel_prl prl;
 861         struct ip_tunnel *t;
 862         struct net *net = dev_net(dev);
 863         struct sit_net *sitn = net_generic(net, sit_net_id);
 864
 865         switch (cmd) {
 866         case SIOCGETTUNNEL:
 867                 t = NULL;
 868                 if (dev == sitn->fb_tunnel_dev) {
 869                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 870                                 err = -EFAULT;
 871                                 break;
 872                         }
 873                         t = ipip6_tunnel_locate(net, &p, 0);
 874                 }
 875                 if (t == NULL)
 876                         t = netdev_priv(dev);
 877                 memcpy(&p, &t->parms, sizeof(p));
 878                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 879                         err = -EFAULT;
 880                 break;
 881
 882         case SIOCADDTUNNEL:
 883         case SIOCCHGTUNNEL:
 884                 err = -EPERM;
 885                 if (!capable(CAP_NET_ADMIN))
 886                         goto done;
 887
 888                 err = -EFAULT;
 889                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 890                         goto done;
 891
 892                 err = -EINVAL;
 893                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 894                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 895                         goto done;
 896                 if (p.iph.ttl)
 897                         p.iph.frag_off |= htons(IP_DF);
 898
 899                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 900
 901                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 902                         if (t != NULL) {
 903                                 if (t->dev != dev) {
 904                                         err = -EEXIST;
 905                                         break;
 906                                 }
 907                         } else {
 908                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 909                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 910                                         err = -EINVAL;
 911                                         break;
 912                                 }
 913                                 t = netdev_priv(dev);
 914                                 ipip6_tunnel_unlink(sitn, t);
 915                                 t->parms.iph.saddr = p.iph.saddr;
 916                                 t->parms.iph.daddr = p.iph.daddr;
 917                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 918                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 919                                 ipip6_tunnel_link(sitn, t);
 920                                 netdev_state_change(dev);
 921                         }
 922                 }
 923
 924                 if (t) {
 925                         err = 0;
 926                         if (cmd == SIOCCHGTUNNEL) {
 927                                 t->parms.iph.ttl = p.iph.ttl;
 928                                 t->parms.iph.tos = p.iph.tos;
 929                                 if (t->parms.link != p.link) {
 930                                         t->parms.link = p.link;
 931                                         ipip6_tunnel_bind_dev(dev);
 932                                         netdev_state_change(dev);
 933                                 }
 934                         }
 935                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 936                                 err = -EFAULT;
 937                 } else
 938                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 939                 break;
 940
 941         case SIOCDELTUNNEL:
 942                 err = -EPERM;
 943                 if (!capable(CAP_NET_ADMIN))
 944                         goto done;
 945
 946                 if (dev == sitn->fb_tunnel_dev) {
 947                         err = -EFAULT;
 948                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 949                                 goto done;
 950                         err = -ENOENT;
 951                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 952                                 goto done;
 953                         err = -EPERM;
 954                         if (t == netdev_priv(sitn->fb_tunnel_dev))
 955                                 goto done;
 956                         dev = t->dev;
 957                 }
 958                 unregister_netdevice(dev);
 959                 err = 0;
 960                 break;
 961
 962         case SIOCGETPRL:
 963         case SIOCADDPRL:
 964         case SIOCDELPRL:
 965         case SIOCCHGPRL:
 966                 err = -EPERM;
 967                 if (cmd != SIOCGETPRL && !capable(CAP_NET_ADMIN))
 968                         goto done;
 969                 err = -EINVAL;
 970                 if (dev == sitn->fb_tunnel_dev)
 971                         goto done;
 972                 err = -EFAULT;
 973                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
 974                         goto done;
 975                 err = -ENOENT;
 976                 if (!(t = netdev_priv(dev)))
 977                         goto done;
 978
 979                 switch (cmd) {
 980                 case SIOCGETPRL:
 981                         err = ipip6_tunnel_get_prl(t, &prl);
 982                         if (!err && copy_to_user(ifr->ifr_ifru.ifru_data,
 983                                                  &prl, sizeof(prl)))
 984                                 err = -EFAULT;
 985                         break;
 986                 case SIOCDELPRL:
 987                         err = ipip6_tunnel_del_prl(t, &prl);
 988                         break;
 989                 case SIOCADDPRL:
 990                 case SIOCCHGPRL:
 991                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 992                         break;
 993                 }
 994                 if (cmd != SIOCGETPRL)
 995                         netdev_state_change(dev);
 996                 break;
 997
 998         default:
 999                 err = -EINVAL;
1000         }
1001
1002 done:
1003         return err;
1004 }
1005
1006 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev)
1007 {
1008         return &(((struct ip_tunnel*)netdev_priv(dev))->stat);
1009 }
1010
1011 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1012 {
1013         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1014                 return -EINVAL;
1015         dev->mtu = new_mtu;
1016         return 0;
1017 }
1018
1019 static void ipip6_tunnel_setup(struct net_device *dev)
1020 {
1021         dev->uninit             = ipip6_tunnel_uninit;
1022         dev->destructor         = free_netdev;
1023         dev->hard_start_xmit    = ipip6_tunnel_xmit;
1024         dev->get_stats          = ipip6_tunnel_get_stats;
1025         dev->do_ioctl           = ipip6_tunnel_ioctl;
1026         dev->change_mtu         = ipip6_tunnel_change_mtu;
1027
1028         dev->type               = ARPHRD_SIT;
1029         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1030         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1031         dev->flags              = IFF_NOARP;
1032         dev->iflink             = 0;
1033         dev->addr_len           = 4;
1034         dev->features           |= NETIF_F_NETNS_LOCAL;
1035 }
1036
1037 static int ipip6_tunnel_init(struct net_device *dev)
1038 {
1039         struct ip_tunnel *tunnel;
1040
1041         tunnel = netdev_priv(dev);
1042
1043         tunnel->dev = dev;
1044         strcpy(tunnel->parms.name, dev->name);
1045
1046         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1047         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1048
1049         ipip6_tunnel_bind_dev(dev);
1050
1051         return 0;
1052 }
1053
1054 static int ipip6_fb_tunnel_init(struct net_device *dev)
1055 {
1056         struct ip_tunnel *tunnel = netdev_priv(dev);
1057         struct iphdr *iph = &tunnel->parms.iph;
1058         struct net *net = dev_net(dev);
1059         struct sit_net *sitn = net_generic(net, sit_net_id);
1060
1061         tunnel->dev = dev;
1062         strcpy(tunnel->parms.name, dev->name);
1063
1064         iph->version            = 4;
1065         iph->protocol           = IPPROTO_IPV6;
1066         iph->ihl                = 5;
1067         iph->ttl                = 64;
1068
1069         dev_hold(dev);
1070         sitn->tunnels_wc[0]     = tunnel;
1071         return 0;
1072 }
1073
1074 static struct xfrm_tunnel sit_handler = {
1075         .handler        =       ipip6_rcv,
1076         .err_handler    =       ipip6_err,
1077         .priority       =       1,
1078 };
1079
1080 static void sit_destroy_tunnels(struct sit_net *sitn)
1081 {
1082         int prio;
1083
1084         for (prio = 1; prio < 4; prio++) {
1085                 int h;
1086                 for (h = 0; h < HASH_SIZE; h++) {
1087                         struct ip_tunnel *t;
1088                         while ((t = sitn->tunnels[prio][h]) != NULL)
1089                                 unregister_netdevice(t->dev);
1090                 }
1091         }
1092 }
1093
1094 static int sit_init_net(struct net *net)
1095 {
1096         int err;
1097         struct sit_net *sitn;
1098
1099         err = -ENOMEM;
1100         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1101         if (sitn == NULL)
1102                 goto err_alloc;
1103
1104         err = net_assign_generic(net, sit_net_id, sitn);
1105         if (err < 0)
1106                 goto err_assign;
1107
1108         sitn->tunnels[0] = sitn->tunnels_wc;
1109         sitn->tunnels[1] = sitn->tunnels_l;
1110         sitn->tunnels[2] = sitn->tunnels_r;
1111         sitn->tunnels[3] = sitn->tunnels_r_l;
1112
1113         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1114                                            ipip6_tunnel_setup);
1115         if (!sitn->fb_tunnel_dev) {
1116                 err = -ENOMEM;
1117                 goto err_alloc_dev;
1118         }
1119
1120         sitn->fb_tunnel_dev->init = ipip6_fb_tunnel_init;
1121         dev_net_set(sitn->fb_tunnel_dev, net);
1122
1123         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1124                 goto err_reg_dev;
1125
1126         return 0;
1127
1128 err_reg_dev:
1129         free_netdev(sitn->fb_tunnel_dev);
1130 err_alloc_dev:
1131         /* nothing */
1132 err_assign:
1133         kfree(sitn);
1134 err_alloc:
1135         return err;
1136 }
1137
1138 static void sit_exit_net(struct net *net)
1139 {
1140         struct sit_net *sitn;
1141
1142         sitn = net_generic(net, sit_net_id);
1143         rtnl_lock();
1144         sit_destroy_tunnels(sitn);
1145         unregister_netdevice(sitn->fb_tunnel_dev);
1146         rtnl_unlock();
1147         kfree(sitn);
1148 }
1149
1150 static struct pernet_operations sit_net_ops = {
1151         .init = sit_init_net,
1152         .exit = sit_exit_net,
1153 };
1154
1155 static void __exit sit_cleanup(void)
1156 {
1157         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1158
1159         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1160 }
1161
1162 static int __init sit_init(void)
1163 {
1164         int err;
1165
1166         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1167
1168         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1169                 printk(KERN_INFO "sit init: Can't add protocol\n");
1170                 return -EAGAIN;
1171         }
1172
1173         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1174         if (err < 0)
1175                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1176
1177         return err;
1178 }
1179
1180 module_init(sit_init);
1181 module_exit(sit_cleanup);
1182 MODULE_LICENSE("GPL");
1183 MODULE_ALIAS("sit0");