SAFE public projects git trees. - safe/jmp/linux-2.6/blob - net/ipv6/sit.c

   1 /*
   2  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   8  *
   9  *      This program is free software; you can redistribute it and/or
  10  *      modify it under the terms of the GNU General Public License
  11  *      as published by the Free Software Foundation; either version
  12  *      2 of the License, or (at your option) any later version.
  13  *
  14  *      Changes:
  15  * Roger Venning <r.venning@telstra.com>:       6to4 support
  16  * Nate Thompson <nate@thebog.net>:             6to4 support
  17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  18  */
  19
  20 #include <linux/module.h>
  21 #include <linux/capability.h>
  22 #include <linux/errno.h>
  23 #include <linux/types.h>
  24 #include <linux/socket.h>
  25 #include <linux/sockios.h>
  26 #include <linux/net.h>
  27 #include <linux/in6.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/if_arp.h>
  30 #include <linux/icmp.h>
  31 #include <asm/uaccess.h>
  32 #include <linux/init.h>
  33 #include <linux/netfilter_ipv4.h>
  34 #include <linux/if_ether.h>
  35
  36 #include <net/sock.h>
  37 #include <net/snmp.h>
  38
  39 #include <net/ipv6.h>
  40 #include <net/protocol.h>
  41 #include <net/transp_v6.h>
  42 #include <net/ip6_fib.h>
  43 #include <net/ip6_route.h>
  44 #include <net/ndisc.h>
  45 #include <net/addrconf.h>
  46 #include <net/ip.h>
  47 #include <net/udp.h>
  48 #include <net/icmp.h>
  49 #include <net/ipip.h>
  50 #include <net/inet_ecn.h>
  51 #include <net/xfrm.h>
  52 #include <net/dsfield.h>
  53 #include <net/net_namespace.h>
  54 #include <net/netns/generic.h>
  55
  56 /*
  57    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  58
  59    For comments look at net/ipv4/ip_gre.c --ANK
  60  */
  61
  62 #define HASH_SIZE  16
  63 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  64
  65 static void ipip6_fb_tunnel_init(struct net_device *dev);
  66 static void ipip6_tunnel_init(struct net_device *dev);
  67 static void ipip6_tunnel_setup(struct net_device *dev);
  68
  69 static int sit_net_id;
  70 struct sit_net {
  71         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  72         struct ip_tunnel *tunnels_r[HASH_SIZE];
  73         struct ip_tunnel *tunnels_l[HASH_SIZE];
  74         struct ip_tunnel *tunnels_wc[1];
  75         struct ip_tunnel **tunnels[4];
  76
  77         struct net_device *fb_tunnel_dev;
  78 };
  79
  80 static DEFINE_RWLOCK(ipip6_lock);
  81
  82 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
  83                 struct net_device *dev, __be32 remote, __be32 local)
  84 {
  85         unsigned h0 = HASH(remote);
  86         unsigned h1 = HASH(local);
  87         struct ip_tunnel *t;
  88         struct sit_net *sitn = net_generic(net, sit_net_id);
  89
  90         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
  91                 if (local == t->parms.iph.saddr &&
  92                     remote == t->parms.iph.daddr &&
  93                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
  94                     (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 &&
  99                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 100                     (t->dev->flags & IFF_UP))
 101                         return t;
 102         }
 103         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
 104                 if (local == t->parms.iph.saddr &&
 105                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 106                     (t->dev->flags & IFF_UP))
 107                         return t;
 108         }
 109         t = sitn->tunnels_wc[0];
 110         if ((t != NULL) && (t->dev->flags & IFF_UP))
 111                 return t;
 112         return NULL;
 113 }
 114
 115 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
 116                 struct ip_tunnel_parm *parms)
 117 {
 118         __be32 remote = parms->iph.daddr;
 119         __be32 local = parms->iph.saddr;
 120         unsigned h = 0;
 121         int prio = 0;
 122
 123         if (remote) {
 124                 prio |= 2;
 125                 h ^= HASH(remote);
 126         }
 127         if (local) {
 128                 prio |= 1;
 129                 h ^= HASH(local);
 130         }
 131         return &sitn->tunnels[prio][h];
 132 }
 133
 134 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
 135                 struct ip_tunnel *t)
 136 {
 137         return __ipip6_bucket(sitn, &t->parms);
 138 }
 139
 140 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 141 {
 142         struct ip_tunnel **tp;
 143
 144         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
 145                 if (t == *tp) {
 146                         write_lock_bh(&ipip6_lock);
 147                         *tp = t->next;
 148                         write_unlock_bh(&ipip6_lock);
 149                         break;
 150                 }
 151         }
 152 }
 153
 154 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 155 {
 156         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 157
 158         t->next = *tp;
 159         write_lock_bh(&ipip6_lock);
 160         *tp = t;
 161         write_unlock_bh(&ipip6_lock);
 162 }
 163
 164 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 165                 struct ip_tunnel_parm *parms, int create)
 166 {
 167         __be32 remote = parms->iph.daddr;
 168         __be32 local = parms->iph.saddr;
 169         struct ip_tunnel *t, **tp, *nt;
 170         struct net_device *dev;
 171         char name[IFNAMSIZ];
 172         struct sit_net *sitn = net_generic(net, sit_net_id);
 173
 174         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
 175                 if (local == t->parms.iph.saddr &&
 176                     remote == t->parms.iph.daddr &&
 177                     parms->link == t->parms.link) {
 178                         if (create)
 179                                 return NULL;
 180                         else
 181                                 return t;
 182                 }
 183         }
 184         if (!create)
 185                 goto failed;
 186
 187         if (parms->name[0])
 188                 strlcpy(name, parms->name, IFNAMSIZ);
 189         else
 190                 sprintf(name, "sit%%d");
 191
 192         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 193         if (dev == NULL)
 194                 return NULL;
 195
 196         dev_net_set(dev, net);
 197
 198         if (strchr(name, '%')) {
 199                 if (dev_alloc_name(dev, name) < 0)
 200                         goto failed_free;
 201         }
 202
 203         nt = netdev_priv(dev);
 204
 205         nt->parms = *parms;
 206         ipip6_tunnel_init(dev);
 207
 208         if (parms->i_flags & SIT_ISATAP)
 209                 dev->priv_flags |= IFF_ISATAP;
 210
 211         if (register_netdevice(dev) < 0)
 212                 goto failed_free;
 213
 214         dev_hold(dev);
 215
 216         ipip6_tunnel_link(sitn, nt);
 217         return nt;
 218
 219 failed_free:
 220         free_netdev(dev);
 221 failed:
 222         return NULL;
 223 }
 224
 225 static struct ip_tunnel_prl_entry *
 226 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 227 {
 228         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
 229
 230         for (p = t->prl; p; p = p->next)
 231                 if (p->addr == addr)
 232                         break;
 233         return p;
 234
 235 }
 236
 237 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 238                                 struct ip_tunnel_prl __user *a)
 239 {
 240         struct ip_tunnel_prl kprl, *kp;
 241         struct ip_tunnel_prl_entry *prl;
 242         unsigned int cmax, c = 0, ca, len;
 243         int ret = 0;
 244
 245         if (copy_from_user(&kprl, a, sizeof(kprl)))
 246                 return -EFAULT;
 247         cmax = kprl.datalen / sizeof(kprl);
 248         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 249                 cmax = 1;
 250
 251         /* For simple GET or for root users,
 252          * we try harder to allocate.
 253          */
 254         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 255                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 256                 NULL;
 257
 258         read_lock(&ipip6_lock);
 259
 260         ca = t->prl_count < cmax ? t->prl_count : cmax;
 261
 262         if (!kp) {
 263                 /* We don't try hard to allocate much memory for
 264                  * non-root users.
 265                  * For root users, retry allocating enough memory for
 266                  * the answer.
 267                  */
 268                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 269                 if (!kp) {
 270                         ret = -ENOMEM;
 271                         goto out;
 272                 }
 273         }
 274
 275         c = 0;
 276         for (prl = t->prl; prl; prl = prl->next) {
 277                 if (c > cmax)
 278                         break;
 279                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 280                         continue;
 281                 kp[c].addr = prl->addr;
 282                 kp[c].flags = prl->flags;
 283                 c++;
 284                 if (kprl.addr != htonl(INADDR_ANY))
 285                         break;
 286         }
 287 out:
 288         read_unlock(&ipip6_lock);
 289
 290         len = sizeof(*kp) * c;
 291         ret = 0;
 292         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 293                 ret = -EFAULT;
 294
 295         kfree(kp);
 296
 297         return ret;
 298 }
 299
 300 static int
 301 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 302 {
 303         struct ip_tunnel_prl_entry *p;
 304         int err = 0;
 305
 306         if (a->addr == htonl(INADDR_ANY))
 307                 return -EINVAL;
 308
 309         write_lock(&ipip6_lock);
 310
 311         for (p = t->prl; p; p = p->next) {
 312                 if (p->addr == a->addr) {
 313                         if (chg)
 314                                 goto update;
 315                         err = -EEXIST;
 316                         goto out;
 317                 }
 318         }
 319
 320         if (chg) {
 321                 err = -ENXIO;
 322                 goto out;
 323         }
 324
 325         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 326         if (!p) {
 327                 err = -ENOBUFS;
 328                 goto out;
 329         }
 330
 331         p->next = t->prl;
 332         t->prl = p;
 333         t->prl_count++;
 334 update:
 335         p->addr = a->addr;
 336         p->flags = a->flags;
 337 out:
 338         write_unlock(&ipip6_lock);
 339         return err;
 340 }
 341
 342 static int
 343 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 344 {
 345         struct ip_tunnel_prl_entry *x, **p;
 346         int err = 0;
 347
 348         write_lock(&ipip6_lock);
 349
 350         if (a && a->addr != htonl(INADDR_ANY)) {
 351                 for (p = &t->prl; *p; p = &(*p)->next) {
 352                         if ((*p)->addr == a->addr) {
 353                                 x = *p;
 354                                 *p = x->next;
 355                                 kfree(x);
 356                                 t->prl_count--;
 357                                 goto out;
 358                         }
 359                 }
 360                 err = -ENXIO;
 361         } else {
 362                 while (t->prl) {
 363                         x = t->prl;
 364                         t->prl = t->prl->next;
 365                         kfree(x);
 366                         t->prl_count--;
 367                 }
 368         }
 369 out:
 370         write_unlock(&ipip6_lock);
 371         return 0;
 372 }
 373
 374 static int
 375 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 376 {
 377         struct ip_tunnel_prl_entry *p;
 378         int ok = 1;
 379
 380         read_lock(&ipip6_lock);
 381         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 382         if (p) {
 383                 if (p->flags & PRL_DEFAULT)
 384                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 385                 else
 386                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 387         } else {
 388                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 389                 if (ipv6_addr_is_isatap(addr6) &&
 390                     (addr6->s6_addr32[3] == iph->saddr) &&
 391                     ipv6_chk_prefix(addr6, t->dev))
 392                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 393                 else
 394                         ok = 0;
 395         }
 396         read_unlock(&ipip6_lock);
 397         return ok;
 398 }
 399
 400 static void ipip6_tunnel_uninit(struct net_device *dev)
 401 {
 402         struct net *net = dev_net(dev);
 403         struct sit_net *sitn = net_generic(net, sit_net_id);
 404
 405         if (dev == sitn->fb_tunnel_dev) {
 406                 write_lock_bh(&ipip6_lock);
 407                 sitn->tunnels_wc[0] = NULL;
 408                 write_unlock_bh(&ipip6_lock);
 409                 dev_put(dev);
 410         } else {
 411                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 412                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 413                 dev_put(dev);
 414         }
 415 }
 416
 417
 418 static int ipip6_err(struct sk_buff *skb, u32 info)
 419 {
 420
 421 /* All the routers (except for Linux) return only
 422    8 bytes of packet payload. It means, that precise relaying of
 423    ICMP in the real Internet is absolutely infeasible.
 424  */
 425         struct iphdr *iph = (struct iphdr*)skb->data;
 426         const int type = icmp_hdr(skb)->type;
 427         const int code = icmp_hdr(skb)->code;
 428         struct ip_tunnel *t;
 429         int err;
 430
 431         switch (type) {
 432         default:
 433         case ICMP_PARAMETERPROB:
 434                 return 0;
 435
 436         case ICMP_DEST_UNREACH:
 437                 switch (code) {
 438                 case ICMP_SR_FAILED:
 439                 case ICMP_PORT_UNREACH:
 440                         /* Impossible event. */
 441                         return 0;
 442                 case ICMP_FRAG_NEEDED:
 443                         /* Soft state for pmtu is maintained by IP core. */
 444                         return 0;
 445                 default:
 446                         /* All others are translated to HOST_UNREACH.
 447                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 448                            I believe they are just ether pollution. --ANK
 449                          */
 450                         break;
 451                 }
 452                 break;
 453         case ICMP_TIME_EXCEEDED:
 454                 if (code != ICMP_EXC_TTL)
 455                         return 0;
 456                 break;
 457         }
 458
 459         err = -ENOENT;
 460
 461         read_lock(&ipip6_lock);
 462         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 463                                 skb->dev,
 464                                 iph->daddr,
 465                                 iph->saddr);
 466         if (t == NULL || t->parms.iph.daddr == 0)
 467                 goto out;
 468
 469         err = 0;
 470         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 471                 goto out;
 472
 473         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 474                 t->err_count++;
 475         else
 476                 t->err_count = 1;
 477         t->err_time = jiffies;
 478 out:
 479         read_unlock(&ipip6_lock);
 480         return err;
 481 }
 482
 483 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 484 {
 485         if (INET_ECN_is_ce(iph->tos))
 486                 IP6_ECN_set_ce(ipv6_hdr(skb));
 487 }
 488
 489 static int ipip6_rcv(struct sk_buff *skb)
 490 {
 491         struct iphdr *iph;
 492         struct ip_tunnel *tunnel;
 493
 494         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 495                 goto out;
 496
 497         iph = ip_hdr(skb);
 498
 499         read_lock(&ipip6_lock);
 500         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 501                                      iph->saddr, iph->daddr);
 502         if (tunnel != NULL) {
 503                 secpath_reset(skb);
 504                 skb->mac_header = skb->network_header;
 505                 skb_reset_network_header(skb);
 506                 IPCB(skb)->flags = 0;
 507                 skb->protocol = htons(ETH_P_IPV6);
 508                 skb->pkt_type = PACKET_HOST;
 509
 510                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 511                     !isatap_chksrc(skb, iph, tunnel)) {
 512                         tunnel->dev->stats.rx_errors++;
 513                         read_unlock(&ipip6_lock);
 514                         kfree_skb(skb);
 515                         return 0;
 516                 }
 517                 tunnel->dev->stats.rx_packets++;
 518                 tunnel->dev->stats.rx_bytes += skb->len;
 519                 skb->dev = tunnel->dev;
 520                 dst_release(skb->dst);
 521                 skb->dst = NULL;
 522                 nf_reset(skb);
 523                 ipip6_ecn_decapsulate(iph, skb);
 524                 netif_rx(skb);
 525                 read_unlock(&ipip6_lock);
 526                 return 0;
 527         }
 528
 529         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 530         read_unlock(&ipip6_lock);
 531 out:
 532         kfree_skb(skb);
 533         return 0;
 534 }
 535
 536 /* Returns the embedded IPv4 address if the IPv6 address
 537    comes from 6to4 (RFC 3056) addr space */
 538
 539 static inline __be32 try_6to4(struct in6_addr *v6dst)
 540 {
 541         __be32 dst = 0;
 542
 543         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 544                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 545                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 546         }
 547         return dst;
 548 }
 549
 550 /*
 551  *      This function assumes it is being called from dev_queue_xmit()
 552  *      and that skb is filled properly by that function.
 553  */
 554
 555 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 556 {
 557         struct ip_tunnel *tunnel = netdev_priv(dev);
 558         struct net_device_stats *stats = &tunnel->dev->stats;
 559         struct iphdr  *tiph = &tunnel->parms.iph;
 560         struct ipv6hdr *iph6 = ipv6_hdr(skb);
 561         u8     tos = tunnel->parms.iph.tos;
 562         struct rtable *rt;                      /* Route to the other host */
 563         struct net_device *tdev;                        /* Device to other host */
 564         struct iphdr  *iph;                     /* Our new IP header */
 565         unsigned int max_headroom;              /* The extra header space needed */
 566         __be32 dst = tiph->daddr;
 567         int    mtu;
 568         struct in6_addr *addr6;
 569         int addr_type;
 570
 571         if (tunnel->recursion++) {
 572                 stats->collisions++;
 573                 goto tx_error;
 574         }
 575
 576         if (skb->protocol != htons(ETH_P_IPV6))
 577                 goto tx_error;
 578
 579         /* ISATAP (RFC4214) - must come before 6to4 */
 580         if (dev->priv_flags & IFF_ISATAP) {
 581                 struct neighbour *neigh = NULL;
 582
 583                 if (skb->dst)
 584                         neigh = skb->dst->neighbour;
 585
 586                 if (neigh == NULL) {
 587                         if (net_ratelimit())
 588                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 589                         goto tx_error;
 590                 }
 591
 592                 addr6 = (struct in6_addr*)&neigh->primary_key;
 593                 addr_type = ipv6_addr_type(addr6);
 594
 595                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 596                      ipv6_addr_is_isatap(addr6))
 597                         dst = addr6->s6_addr32[3];
 598                 else
 599                         goto tx_error;
 600         }
 601
 602         if (!dst)
 603                 dst = try_6to4(&iph6->daddr);
 604
 605         if (!dst) {
 606                 struct neighbour *neigh = NULL;
 607
 608                 if (skb->dst)
 609                         neigh = skb->dst->neighbour;
 610
 611                 if (neigh == NULL) {
 612                         if (net_ratelimit())
 613                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 614                         goto tx_error;
 615                 }
 616
 617                 addr6 = (struct in6_addr*)&neigh->primary_key;
 618                 addr_type = ipv6_addr_type(addr6);
 619
 620                 if (addr_type == IPV6_ADDR_ANY) {
 621                         addr6 = &ipv6_hdr(skb)->daddr;
 622                         addr_type = ipv6_addr_type(addr6);
 623                 }
 624
 625                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 626                         goto tx_error_icmp;
 627
 628                 dst = addr6->s6_addr32[3];
 629         }
 630
 631         {
 632                 struct flowi fl = { .nl_u = { .ip4_u =
 633                                               { .daddr = dst,
 634                                                 .saddr = tiph->saddr,
 635                                                 .tos = RT_TOS(tos) } },
 636                                     .oif = tunnel->parms.link,
 637                                     .proto = IPPROTO_IPV6 };
 638                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 639                         stats->tx_carrier_errors++;
 640                         goto tx_error_icmp;
 641                 }
 642         }
 643         if (rt->rt_type != RTN_UNICAST) {
 644                 ip_rt_put(rt);
 645                 stats->tx_carrier_errors++;
 646                 goto tx_error_icmp;
 647         }
 648         tdev = rt->u.dst.dev;
 649
 650         if (tdev == dev) {
 651                 ip_rt_put(rt);
 652                 stats->collisions++;
 653                 goto tx_error;
 654         }
 655
 656         if (tiph->frag_off)
 657                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 658         else
 659                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
 660
 661         if (mtu < 68) {
 662                 stats->collisions++;
 663                 ip_rt_put(rt);
 664                 goto tx_error;
 665         }
 666         if (mtu < IPV6_MIN_MTU)
 667                 mtu = IPV6_MIN_MTU;
 668         if (tunnel->parms.iph.daddr && skb->dst)
 669                 skb->dst->ops->update_pmtu(skb->dst, mtu);
 670
 671         if (skb->len > mtu) {
 672                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 673                 ip_rt_put(rt);
 674                 goto tx_error;
 675         }
 676
 677         if (tunnel->err_count > 0) {
 678                 if (time_before(jiffies,
 679                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 680                         tunnel->err_count--;
 681                         dst_link_failure(skb);
 682                 } else
 683                         tunnel->err_count = 0;
 684         }
 685
 686         /*
 687          * Okay, now see if we can stuff it in the buffer as-is.
 688          */
 689         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 690
 691         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 692             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 693                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 694                 if (!new_skb) {
 695                         ip_rt_put(rt);
 696                         stats->tx_dropped++;
 697                         dev_kfree_skb(skb);
 698                         tunnel->recursion--;
 699                         return 0;
 700                 }
 701                 if (skb->sk)
 702                         skb_set_owner_w(new_skb, skb->sk);
 703                 dev_kfree_skb(skb);
 704                 skb = new_skb;
 705                 iph6 = ipv6_hdr(skb);
 706         }
 707
 708         skb->transport_header = skb->network_header;
 709         skb_push(skb, sizeof(struct iphdr));
 710         skb_reset_network_header(skb);
 711         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 712         IPCB(skb)->flags = 0;
 713         dst_release(skb->dst);
 714         skb->dst = &rt->u.dst;
 715
 716         /*
 717          *      Push down and install the IPIP header.
 718          */
 719
 720         iph                     =       ip_hdr(skb);
 721         iph->version            =       4;
 722         iph->ihl                =       sizeof(struct iphdr)>>2;
 723         if (mtu > IPV6_MIN_MTU)
 724                 iph->frag_off   =       htons(IP_DF);
 725         else
 726                 iph->frag_off   =       0;
 727
 728         iph->protocol           =       IPPROTO_IPV6;
 729         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 730         iph->daddr              =       rt->rt_dst;
 731         iph->saddr              =       rt->rt_src;
 732
 733         if ((iph->ttl = tiph->ttl) == 0)
 734                 iph->ttl        =       iph6->hop_limit;
 735
 736         nf_reset(skb);
 737
 738         IPTUNNEL_XMIT();
 739         tunnel->recursion--;
 740         return 0;
 741
 742 tx_error_icmp:
 743         dst_link_failure(skb);
 744 tx_error:
 745         stats->tx_errors++;
 746         dev_kfree_skb(skb);
 747         tunnel->recursion--;
 748         return 0;
 749 }
 750
 751 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 752 {
 753         struct net_device *tdev = NULL;
 754         struct ip_tunnel *tunnel;
 755         struct iphdr *iph;
 756
 757         tunnel = netdev_priv(dev);
 758         iph = &tunnel->parms.iph;
 759
 760         if (iph->daddr) {
 761                 struct flowi fl = { .nl_u = { .ip4_u =
 762                                               { .daddr = iph->daddr,
 763                                                 .saddr = iph->saddr,
 764                                                 .tos = RT_TOS(iph->tos) } },
 765                                     .oif = tunnel->parms.link,
 766                                     .proto = IPPROTO_IPV6 };
 767                 struct rtable *rt;
 768                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 769                         tdev = rt->u.dst.dev;
 770                         ip_rt_put(rt);
 771                 }
 772                 dev->flags |= IFF_POINTOPOINT;
 773         }
 774
 775         if (!tdev && tunnel->parms.link)
 776                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 777
 778         if (tdev) {
 779                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 780                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 781                 if (dev->mtu < IPV6_MIN_MTU)
 782                         dev->mtu = IPV6_MIN_MTU;
 783         }
 784         dev->iflink = tunnel->parms.link;
 785 }
 786
 787 static int
 788 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 789 {
 790         int err = 0;
 791         struct ip_tunnel_parm p;
 792         struct ip_tunnel_prl prl;
 793         struct ip_tunnel *t;
 794         struct net *net = dev_net(dev);
 795         struct sit_net *sitn = net_generic(net, sit_net_id);
 796
 797         switch (cmd) {
 798         case SIOCGETTUNNEL:
 799                 t = NULL;
 800                 if (dev == sitn->fb_tunnel_dev) {
 801                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 802                                 err = -EFAULT;
 803                                 break;
 804                         }
 805                         t = ipip6_tunnel_locate(net, &p, 0);
 806                 }
 807                 if (t == NULL)
 808                         t = netdev_priv(dev);
 809                 memcpy(&p, &t->parms, sizeof(p));
 810                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 811                         err = -EFAULT;
 812                 break;
 813
 814         case SIOCADDTUNNEL:
 815         case SIOCCHGTUNNEL:
 816                 err = -EPERM;
 817                 if (!capable(CAP_NET_ADMIN))
 818                         goto done;
 819
 820                 err = -EFAULT;
 821                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 822                         goto done;
 823
 824                 err = -EINVAL;
 825                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 826                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 827                         goto done;
 828                 if (p.iph.ttl)
 829                         p.iph.frag_off |= htons(IP_DF);
 830
 831                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 832
 833                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 834                         if (t != NULL) {
 835                                 if (t->dev != dev) {
 836                                         err = -EEXIST;
 837                                         break;
 838                                 }
 839                         } else {
 840                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 841                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 842                                         err = -EINVAL;
 843                                         break;
 844                                 }
 845                                 t = netdev_priv(dev);
 846                                 ipip6_tunnel_unlink(sitn, t);
 847                                 t->parms.iph.saddr = p.iph.saddr;
 848                                 t->parms.iph.daddr = p.iph.daddr;
 849                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 850                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 851                                 ipip6_tunnel_link(sitn, t);
 852                                 netdev_state_change(dev);
 853                         }
 854                 }
 855
 856                 if (t) {
 857                         err = 0;
 858                         if (cmd == SIOCCHGTUNNEL) {
 859                                 t->parms.iph.ttl = p.iph.ttl;
 860                                 t->parms.iph.tos = p.iph.tos;
 861                                 if (t->parms.link != p.link) {
 862                                         t->parms.link = p.link;
 863                                         ipip6_tunnel_bind_dev(dev);
 864                                         netdev_state_change(dev);
 865                                 }
 866                         }
 867                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 868                                 err = -EFAULT;
 869                 } else
 870                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 871                 break;
 872
 873         case SIOCDELTUNNEL:
 874                 err = -EPERM;
 875                 if (!capable(CAP_NET_ADMIN))
 876                         goto done;
 877
 878                 if (dev == sitn->fb_tunnel_dev) {
 879                         err = -EFAULT;
 880                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 881                                 goto done;
 882                         err = -ENOENT;
 883                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 884                                 goto done;
 885                         err = -EPERM;
 886                         if (t == netdev_priv(sitn->fb_tunnel_dev))
 887                                 goto done;
 888                         dev = t->dev;
 889                 }
 890                 unregister_netdevice(dev);
 891                 err = 0;
 892                 break;
 893
 894         case SIOCGETPRL:
 895                 err = -EINVAL;
 896                 if (dev == sitn->fb_tunnel_dev)
 897                         goto done;
 898                 err = -ENOENT;
 899                 if (!(t = netdev_priv(dev)))
 900                         goto done;
 901                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
 902                 break;
 903
 904         case SIOCADDPRL:
 905         case SIOCDELPRL:
 906         case SIOCCHGPRL:
 907                 err = -EPERM;
 908                 if (!capable(CAP_NET_ADMIN))
 909                         goto done;
 910                 err = -EINVAL;
 911                 if (dev == sitn->fb_tunnel_dev)
 912                         goto done;
 913                 err = -EFAULT;
 914                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
 915                         goto done;
 916                 err = -ENOENT;
 917                 if (!(t = netdev_priv(dev)))
 918                         goto done;
 919
 920                 switch (cmd) {
 921                 case SIOCDELPRL:
 922                         err = ipip6_tunnel_del_prl(t, &prl);
 923                         break;
 924                 case SIOCADDPRL:
 925                 case SIOCCHGPRL:
 926                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 927                         break;
 928                 }
 929                 netdev_state_change(dev);
 930                 break;
 931
 932         default:
 933                 err = -EINVAL;
 934         }
 935
 936 done:
 937         return err;
 938 }
 939
 940 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 941 {
 942         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 943                 return -EINVAL;
 944         dev->mtu = new_mtu;
 945         return 0;
 946 }
 947
 948 static const struct net_device_ops ipip6_netdev_ops = {
 949         .ndo_uninit     = ipip6_tunnel_uninit,
 950         .ndo_start_xmit = ipip6_tunnel_xmit,
 951         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
 952         .ndo_change_mtu = ipip6_tunnel_change_mtu,
 953 };
 954
 955 static void ipip6_tunnel_setup(struct net_device *dev)
 956 {
 957         dev->netdev_ops         = &ipip6_netdev_ops;
 958         dev->destructor         = free_netdev;
 959
 960         dev->type               = ARPHRD_SIT;
 961         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 962         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 963         dev->flags              = IFF_NOARP;
 964         dev->iflink             = 0;
 965         dev->addr_len           = 4;
 966         dev->features           |= NETIF_F_NETNS_LOCAL;
 967 }
 968
 969 static void ipip6_tunnel_init(struct net_device *dev)
 970 {
 971         struct ip_tunnel *tunnel = netdev_priv(dev);
 972
 973         tunnel->dev = dev;
 974         strcpy(tunnel->parms.name, dev->name);
 975
 976         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 977         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 978
 979         ipip6_tunnel_bind_dev(dev);
 980 }
 981
 982 static void ipip6_fb_tunnel_init(struct net_device *dev)
 983 {
 984         struct ip_tunnel *tunnel = netdev_priv(dev);
 985         struct iphdr *iph = &tunnel->parms.iph;
 986         struct net *net = dev_net(dev);
 987         struct sit_net *sitn = net_generic(net, sit_net_id);
 988
 989         tunnel->dev = dev;
 990         strcpy(tunnel->parms.name, dev->name);
 991
 992         iph->version            = 4;
 993         iph->protocol           = IPPROTO_IPV6;
 994         iph->ihl                = 5;
 995         iph->ttl                = 64;
 996
 997         dev_hold(dev);
 998         sitn->tunnels_wc[0]     = tunnel;
 999 }
1000
1001 static struct xfrm_tunnel sit_handler = {
1002         .handler        =       ipip6_rcv,
1003         .err_handler    =       ipip6_err,
1004         .priority       =       1,
1005 };
1006
1007 static void sit_destroy_tunnels(struct sit_net *sitn)
1008 {
1009         int prio;
1010
1011         for (prio = 1; prio < 4; prio++) {
1012                 int h;
1013                 for (h = 0; h < HASH_SIZE; h++) {
1014                         struct ip_tunnel *t;
1015                         while ((t = sitn->tunnels[prio][h]) != NULL)
1016                                 unregister_netdevice(t->dev);
1017                 }
1018         }
1019 }
1020
1021 static int sit_init_net(struct net *net)
1022 {
1023         int err;
1024         struct sit_net *sitn;
1025
1026         err = -ENOMEM;
1027         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1028         if (sitn == NULL)
1029                 goto err_alloc;
1030
1031         err = net_assign_generic(net, sit_net_id, sitn);
1032         if (err < 0)
1033                 goto err_assign;
1034
1035         sitn->tunnels[0] = sitn->tunnels_wc;
1036         sitn->tunnels[1] = sitn->tunnels_l;
1037         sitn->tunnels[2] = sitn->tunnels_r;
1038         sitn->tunnels[3] = sitn->tunnels_r_l;
1039
1040         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1041                                            ipip6_tunnel_setup);
1042         if (!sitn->fb_tunnel_dev) {
1043                 err = -ENOMEM;
1044                 goto err_alloc_dev;
1045         }
1046         dev_net_set(sitn->fb_tunnel_dev, net);
1047
1048         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1049
1050         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1051                 goto err_reg_dev;
1052
1053         return 0;
1054
1055 err_reg_dev:
1056         dev_put(sitn->fb_tunnel_dev);
1057         free_netdev(sitn->fb_tunnel_dev);
1058 err_alloc_dev:
1059         /* nothing */
1060 err_assign:
1061         kfree(sitn);
1062 err_alloc:
1063         return err;
1064 }
1065
1066 static void sit_exit_net(struct net *net)
1067 {
1068         struct sit_net *sitn;
1069
1070         sitn = net_generic(net, sit_net_id);
1071         rtnl_lock();
1072         sit_destroy_tunnels(sitn);
1073         unregister_netdevice(sitn->fb_tunnel_dev);
1074         rtnl_unlock();
1075         kfree(sitn);
1076 }
1077
1078 static struct pernet_operations sit_net_ops = {
1079         .init = sit_init_net,
1080         .exit = sit_exit_net,
1081 };
1082
1083 static void __exit sit_cleanup(void)
1084 {
1085         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1086
1087         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1088 }
1089
1090 static int __init sit_init(void)
1091 {
1092         int err;
1093
1094         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1095
1096         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1097                 printk(KERN_INFO "sit init: Can't add protocol\n");
1098                 return -EAGAIN;
1099         }
1100
1101         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1102         if (err < 0)
1103                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1104
1105         return err;
1106 }
1107
1108 module_init(sit_init);
1109 module_exit(sit_cleanup);
1110 MODULE_LICENSE("GPL");
1111 MODULE_ALIAS("sit0");