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  * Sascha Hlusiak <mail@saschahlusiak.de>:      stateless autoconf for isatap
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/capability.h>
  23 #include <linux/errno.h>
  24 #include <linux/types.h>
  25 #include <linux/socket.h>
  26 #include <linux/sockios.h>
  27 #include <linux/net.h>
  28 #include <linux/in6.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/if_arp.h>
  31 #include <linux/icmp.h>
  32 #include <asm/uaccess.h>
  33 #include <linux/init.h>
  34 #include <linux/netfilter_ipv4.h>
  35 #include <linux/if_ether.h>
  36
  37 #include <net/sock.h>
  38 #include <net/snmp.h>
  39
  40 #include <net/ipv6.h>
  41 #include <net/protocol.h>
  42 #include <net/transp_v6.h>
  43 #include <net/ip6_fib.h>
  44 #include <net/ip6_route.h>
  45 #include <net/ndisc.h>
  46 #include <net/addrconf.h>
  47 #include <net/ip.h>
  48 #include <net/udp.h>
  49 #include <net/icmp.h>
  50 #include <net/ipip.h>
  51 #include <net/inet_ecn.h>
  52 #include <net/xfrm.h>
  53 #include <net/dsfield.h>
  54 #include <net/net_namespace.h>
  55 #include <net/netns/generic.h>
  56
  57 /*
  58    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  59
  60    For comments look at net/ipv4/ip_gre.c --ANK
  61  */
  62
  63 #define HASH_SIZE  16
  64 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  65
  66 static void ipip6_fb_tunnel_init(struct net_device *dev);
  67 static void ipip6_tunnel_init(struct net_device *dev);
  68 static void ipip6_tunnel_setup(struct net_device *dev);
  69
  70 static int sit_net_id;
  71 struct sit_net {
  72         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  73         struct ip_tunnel *tunnels_r[HASH_SIZE];
  74         struct ip_tunnel *tunnels_l[HASH_SIZE];
  75         struct ip_tunnel *tunnels_wc[1];
  76         struct ip_tunnel **tunnels[4];
  77
  78         struct net_device *fb_tunnel_dev;
  79 };
  80
  81 static DEFINE_RWLOCK(ipip6_lock);
  82
  83 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
  84                 struct net_device *dev, __be32 remote, __be32 local)
  85 {
  86         unsigned h0 = HASH(remote);
  87         unsigned h1 = HASH(local);
  88         struct ip_tunnel *t;
  89         struct sit_net *sitn = net_generic(net, sit_net_id);
  90
  91         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
  92                 if (local == t->parms.iph.saddr &&
  93                     remote == t->parms.iph.daddr &&
  94                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
  95                     (t->dev->flags & IFF_UP))
  96                         return t;
  97         }
  98         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
  99                 if (remote == t->parms.iph.daddr &&
 100                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 101                     (t->dev->flags & IFF_UP))
 102                         return t;
 103         }
 104         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
 105                 if (local == t->parms.iph.saddr &&
 106                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 107                     (t->dev->flags & IFF_UP))
 108                         return t;
 109         }
 110         t = sitn->tunnels_wc[0];
 111         if ((t != NULL) && (t->dev->flags & IFF_UP))
 112                 return t;
 113         return NULL;
 114 }
 115
 116 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
 117                 struct ip_tunnel_parm *parms)
 118 {
 119         __be32 remote = parms->iph.daddr;
 120         __be32 local = parms->iph.saddr;
 121         unsigned h = 0;
 122         int prio = 0;
 123
 124         if (remote) {
 125                 prio |= 2;
 126                 h ^= HASH(remote);
 127         }
 128         if (local) {
 129                 prio |= 1;
 130                 h ^= HASH(local);
 131         }
 132         return &sitn->tunnels[prio][h];
 133 }
 134
 135 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
 136                 struct ip_tunnel *t)
 137 {
 138         return __ipip6_bucket(sitn, &t->parms);
 139 }
 140
 141 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 142 {
 143         struct ip_tunnel **tp;
 144
 145         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
 146                 if (t == *tp) {
 147                         write_lock_bh(&ipip6_lock);
 148                         *tp = t->next;
 149                         write_unlock_bh(&ipip6_lock);
 150                         break;
 151                 }
 152         }
 153 }
 154
 155 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 156 {
 157         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 158
 159         t->next = *tp;
 160         write_lock_bh(&ipip6_lock);
 161         *tp = t;
 162         write_unlock_bh(&ipip6_lock);
 163 }
 164
 165 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 166                 struct ip_tunnel_parm *parms, int create)
 167 {
 168         __be32 remote = parms->iph.daddr;
 169         __be32 local = parms->iph.saddr;
 170         struct ip_tunnel *t, **tp, *nt;
 171         struct net_device *dev;
 172         char name[IFNAMSIZ];
 173         struct sit_net *sitn = net_generic(net, sit_net_id);
 174
 175         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
 176                 if (local == t->parms.iph.saddr &&
 177                     remote == t->parms.iph.daddr &&
 178                     parms->link == t->parms.link) {
 179                         if (create)
 180                                 return NULL;
 181                         else
 182                                 return t;
 183                 }
 184         }
 185         if (!create)
 186                 goto failed;
 187
 188         if (parms->name[0])
 189                 strlcpy(name, parms->name, IFNAMSIZ);
 190         else
 191                 sprintf(name, "sit%%d");
 192
 193         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 194         if (dev == NULL)
 195                 return NULL;
 196
 197         dev_net_set(dev, net);
 198
 199         if (strchr(name, '%')) {
 200                 if (dev_alloc_name(dev, name) < 0)
 201                         goto failed_free;
 202         }
 203
 204         nt = netdev_priv(dev);
 205
 206         nt->parms = *parms;
 207         ipip6_tunnel_init(dev);
 208
 209         if (parms->i_flags & SIT_ISATAP)
 210                 dev->priv_flags |= IFF_ISATAP;
 211
 212         if (register_netdevice(dev) < 0)
 213                 goto failed_free;
 214
 215         dev_hold(dev);
 216
 217         ipip6_tunnel_link(sitn, nt);
 218         return nt;
 219
 220 failed_free:
 221         free_netdev(dev);
 222 failed:
 223         return NULL;
 224 }
 225
 226 static void ipip6_tunnel_rs_timer(unsigned long data)
 227 {
 228         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *) data;
 229         struct inet6_dev *ifp;
 230         struct inet6_ifaddr *addr;
 231
 232         spin_lock(&p->lock);
 233         ifp = __in6_dev_get(p->tunnel->dev);
 234
 235         read_lock_bh(&ifp->lock);
 236         for (addr = ifp->addr_list; addr; addr = addr->if_next) {
 237                 struct in6_addr rtr;
 238
 239                 if (!(ipv6_addr_type(&addr->addr) & IPV6_ADDR_LINKLOCAL))
 240                         continue;
 241
 242                 /* Send RS to guessed linklocal address of router
 243                  *
 244                  * Better: send to ff02::2 encapsuled in unicast directly
 245                  * to router-v4 instead of guessing the v6 address.
 246                  *
 247                  * Cisco/Windows seem to not set the u/l bit correctly,
 248                  * so we won't guess right.
 249                  */
 250                 ipv6_addr_set(&rtr,  htonl(0xFE800000), 0, 0, 0);
 251                 if (!__ipv6_isatap_ifid(rtr.s6_addr + 8,
 252                                         p->addr)) {
 253                         ndisc_send_rs(p->tunnel->dev, &addr->addr, &rtr);
 254                 }
 255         }
 256         read_unlock_bh(&ifp->lock);
 257
 258         mod_timer(&p->rs_timer, jiffies + HZ * p->rs_delay);
 259         spin_unlock(&p->lock);
 260
 261         return;
 262 }
 263
 264 static struct ip_tunnel_prl_entry *
 265 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 266 {
 267         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
 268
 269         for (p = t->prl; p; p = p->next)
 270                 if (p->addr == addr)
 271                         break;
 272         return p;
 273
 274 }
 275
 276 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 277                                 struct ip_tunnel_prl __user *a)
 278 {
 279         struct ip_tunnel_prl kprl, *kp;
 280         struct ip_tunnel_prl_entry *prl;
 281         unsigned int cmax, c = 0, ca, len;
 282         int ret = 0;
 283
 284         if (copy_from_user(&kprl, a, sizeof(kprl)))
 285                 return -EFAULT;
 286         cmax = kprl.datalen / sizeof(kprl);
 287         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 288                 cmax = 1;
 289
 290         /* For simple GET or for root users,
 291          * we try harder to allocate.
 292          */
 293         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 294                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 295                 NULL;
 296
 297         read_lock(&ipip6_lock);
 298
 299         ca = t->prl_count < cmax ? t->prl_count : cmax;
 300
 301         if (!kp) {
 302                 /* We don't try hard to allocate much memory for
 303                  * non-root users.
 304                  * For root users, retry allocating enough memory for
 305                  * the answer.
 306                  */
 307                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 308                 if (!kp) {
 309                         ret = -ENOMEM;
 310                         goto out;
 311                 }
 312         }
 313
 314         c = 0;
 315         for (prl = t->prl; prl; prl = prl->next) {
 316                 if (c > cmax)
 317                         break;
 318                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 319                         continue;
 320                 kp[c].addr = prl->addr;
 321                 kp[c].flags = prl->flags;
 322                 kp[c].rs_delay = prl->rs_delay;
 323                 c++;
 324                 if (kprl.addr != htonl(INADDR_ANY))
 325                         break;
 326         }
 327 out:
 328         read_unlock(&ipip6_lock);
 329
 330         len = sizeof(*kp) * c;
 331         ret = 0;
 332         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 333                 ret = -EFAULT;
 334
 335         kfree(kp);
 336
 337         return ret;
 338 }
 339
 340 static int
 341 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 342 {
 343         struct ip_tunnel_prl_entry *p;
 344         int err = 0;
 345
 346         if (a->addr == htonl(INADDR_ANY))
 347                 return -EINVAL;
 348
 349         write_lock(&ipip6_lock);
 350
 351         for (p = t->prl; p; p = p->next) {
 352                 if (p->addr == a->addr) {
 353                         if (chg)
 354                                 goto update;
 355                         err = -EEXIST;
 356                         goto out;
 357                 }
 358         }
 359
 360         if (chg) {
 361                 err = -ENXIO;
 362                 goto out;
 363         }
 364
 365         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 366         if (!p) {
 367                 err = -ENOBUFS;
 368                 goto out;
 369         }
 370
 371         p->next = t->prl;
 372         p->tunnel = t;
 373         t->prl = p;
 374         t->prl_count++;
 375
 376         spin_lock_init(&p->lock);
 377         setup_timer(&p->rs_timer, ipip6_tunnel_rs_timer, (unsigned long) p);
 378 update:
 379         p->addr = a->addr;
 380         p->flags = a->flags;
 381         p->rs_delay = a->rs_delay;
 382         if (p->rs_delay == 0)
 383                 p->rs_delay = IPTUNNEL_RS_DEFAULT_DELAY;
 384         spin_lock(&p->lock);
 385         del_timer(&p->rs_timer);
 386         if (p->flags & PRL_DEFAULT)
 387                 mod_timer(&p->rs_timer, jiffies + 1);
 388         spin_unlock(&p->lock);
 389 out:
 390         write_unlock(&ipip6_lock);
 391         return err;
 392 }
 393
 394 static int
 395 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 396 {
 397         struct ip_tunnel_prl_entry *x, **p;
 398         int err = 0;
 399
 400         write_lock(&ipip6_lock);
 401
 402         if (a && a->addr != htonl(INADDR_ANY)) {
 403                 for (p = &t->prl; *p; p = &(*p)->next) {
 404                         if ((*p)->addr == a->addr) {
 405                                 x = *p;
 406                                 *p = x->next;
 407                                 spin_lock(&x->lock);
 408                                 del_timer(&x->rs_timer);
 409                                 spin_unlock(&x->lock);
 410                                 kfree(x);
 411                                 t->prl_count--;
 412                                 goto out;
 413                         }
 414                 }
 415                 err = -ENXIO;
 416         } else {
 417                 while (t->prl) {
 418                         x = t->prl;
 419                         t->prl = t->prl->next;
 420                         spin_lock(&x->lock);
 421                         del_timer(&x->rs_timer);
 422                         spin_unlock(&x->lock);
 423                         kfree(x);
 424                         t->prl_count--;
 425                 }
 426         }
 427 out:
 428         write_unlock(&ipip6_lock);
 429         return err;
 430 }
 431
 432 static int
 433 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 434 {
 435         struct ip_tunnel_prl_entry *p;
 436         int ok = 1;
 437
 438         read_lock(&ipip6_lock);
 439         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 440         if (p) {
 441                 if (p->flags & PRL_DEFAULT)
 442                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 443                 else
 444                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 445         } else {
 446                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 447                 if (ipv6_addr_is_isatap(addr6) &&
 448                     (addr6->s6_addr32[3] == iph->saddr) &&
 449                     ipv6_chk_prefix(addr6, t->dev))
 450                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 451                 else
 452                         ok = 0;
 453         }
 454         read_unlock(&ipip6_lock);
 455         return ok;
 456 }
 457
 458 static void ipip6_tunnel_uninit(struct net_device *dev)
 459 {
 460         struct net *net = dev_net(dev);
 461         struct sit_net *sitn = net_generic(net, sit_net_id);
 462
 463         if (dev == sitn->fb_tunnel_dev) {
 464                 write_lock_bh(&ipip6_lock);
 465                 sitn->tunnels_wc[0] = NULL;
 466                 write_unlock_bh(&ipip6_lock);
 467                 dev_put(dev);
 468         } else {
 469                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 470                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 471                 dev_put(dev);
 472         }
 473 }
 474
 475
 476 static int ipip6_err(struct sk_buff *skb, u32 info)
 477 {
 478
 479 /* All the routers (except for Linux) return only
 480    8 bytes of packet payload. It means, that precise relaying of
 481    ICMP in the real Internet is absolutely infeasible.
 482  */
 483         struct iphdr *iph = (struct iphdr*)skb->data;
 484         const int type = icmp_hdr(skb)->type;
 485         const int code = icmp_hdr(skb)->code;
 486         struct ip_tunnel *t;
 487         int err;
 488
 489         switch (type) {
 490         default:
 491         case ICMP_PARAMETERPROB:
 492                 return 0;
 493
 494         case ICMP_DEST_UNREACH:
 495                 switch (code) {
 496                 case ICMP_SR_FAILED:
 497                 case ICMP_PORT_UNREACH:
 498                         /* Impossible event. */
 499                         return 0;
 500                 case ICMP_FRAG_NEEDED:
 501                         /* Soft state for pmtu is maintained by IP core. */
 502                         return 0;
 503                 default:
 504                         /* All others are translated to HOST_UNREACH.
 505                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 506                            I believe they are just ether pollution. --ANK
 507                          */
 508                         break;
 509                 }
 510                 break;
 511         case ICMP_TIME_EXCEEDED:
 512                 if (code != ICMP_EXC_TTL)
 513                         return 0;
 514                 break;
 515         }
 516
 517         err = -ENOENT;
 518
 519         read_lock(&ipip6_lock);
 520         t = ipip6_tunnel_lookup(dev_net(skb->dev),
 521                                 skb->dev,
 522                                 iph->daddr,
 523                                 iph->saddr);
 524         if (t == NULL || t->parms.iph.daddr == 0)
 525                 goto out;
 526
 527         err = 0;
 528         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 529                 goto out;
 530
 531         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 532                 t->err_count++;
 533         else
 534                 t->err_count = 1;
 535         t->err_time = jiffies;
 536 out:
 537         read_unlock(&ipip6_lock);
 538         return err;
 539 }
 540
 541 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 542 {
 543         if (INET_ECN_is_ce(iph->tos))
 544                 IP6_ECN_set_ce(ipv6_hdr(skb));
 545 }
 546
 547 static int ipip6_rcv(struct sk_buff *skb)
 548 {
 549         struct iphdr *iph;
 550         struct ip_tunnel *tunnel;
 551
 552         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 553                 goto out;
 554
 555         iph = ip_hdr(skb);
 556
 557         read_lock(&ipip6_lock);
 558         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 559                                      iph->saddr, iph->daddr);
 560         if (tunnel != NULL) {
 561                 secpath_reset(skb);
 562                 skb->mac_header = skb->network_header;
 563                 skb_reset_network_header(skb);
 564                 IPCB(skb)->flags = 0;
 565                 skb->protocol = htons(ETH_P_IPV6);
 566                 skb->pkt_type = PACKET_HOST;
 567
 568                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 569                     !isatap_chksrc(skb, iph, tunnel)) {
 570                         tunnel->dev->stats.rx_errors++;
 571                         read_unlock(&ipip6_lock);
 572                         kfree_skb(skb);
 573                         return 0;
 574                 }
 575                 tunnel->dev->stats.rx_packets++;
 576                 tunnel->dev->stats.rx_bytes += skb->len;
 577                 skb->dev = tunnel->dev;
 578                 skb_dst_drop(skb);
 579                 nf_reset(skb);
 580                 ipip6_ecn_decapsulate(iph, skb);
 581                 netif_rx(skb);
 582                 read_unlock(&ipip6_lock);
 583                 return 0;
 584         }
 585
 586         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 587         read_unlock(&ipip6_lock);
 588 out:
 589         kfree_skb(skb);
 590         return 0;
 591 }
 592
 593 /* Returns the embedded IPv4 address if the IPv6 address
 594    comes from 6to4 (RFC 3056) addr space */
 595
 596 static inline __be32 try_6to4(struct in6_addr *v6dst)
 597 {
 598         __be32 dst = 0;
 599
 600         if (v6dst->s6_addr16[0] == htons(0x2002)) {
 601                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 602                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
 603         }
 604         return dst;
 605 }
 606
 607 /*
 608  *      This function assumes it is being called from dev_queue_xmit()
 609  *      and that skb is filled properly by that function.
 610  */
 611
 612 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 613                                      struct net_device *dev)
 614 {
 615         struct ip_tunnel *tunnel = netdev_priv(dev);
 616         struct net_device_stats *stats = &tunnel->dev->stats;
 617         struct iphdr  *tiph = &tunnel->parms.iph;
 618         struct ipv6hdr *iph6 = ipv6_hdr(skb);
 619         u8     tos = tunnel->parms.iph.tos;
 620         struct rtable *rt;                      /* Route to the other host */
 621         struct net_device *tdev;                        /* Device to other host */
 622         struct iphdr  *iph;                     /* Our new IP header */
 623         unsigned int max_headroom;              /* The extra header space needed */
 624         __be32 dst = tiph->daddr;
 625         int    mtu;
 626         struct in6_addr *addr6;
 627         int addr_type;
 628
 629         if (skb->protocol != htons(ETH_P_IPV6))
 630                 goto tx_error;
 631
 632         /* ISATAP (RFC4214) - must come before 6to4 */
 633         if (dev->priv_flags & IFF_ISATAP) {
 634                 struct neighbour *neigh = NULL;
 635
 636                 if (skb_dst(skb))
 637                         neigh = skb_dst(skb)->neighbour;
 638
 639                 if (neigh == NULL) {
 640                         if (net_ratelimit())
 641                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 642                         goto tx_error;
 643                 }
 644
 645                 addr6 = (struct in6_addr*)&neigh->primary_key;
 646                 addr_type = ipv6_addr_type(addr6);
 647
 648                 if ((addr_type & IPV6_ADDR_UNICAST) &&
 649                      ipv6_addr_is_isatap(addr6))
 650                         dst = addr6->s6_addr32[3];
 651                 else
 652                         goto tx_error;
 653         }
 654
 655         if (!dst)
 656                 dst = try_6to4(&iph6->daddr);
 657
 658         if (!dst) {
 659                 struct neighbour *neigh = NULL;
 660
 661                 if (skb_dst(skb))
 662                         neigh = skb_dst(skb)->neighbour;
 663
 664                 if (neigh == NULL) {
 665                         if (net_ratelimit())
 666                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
 667                         goto tx_error;
 668                 }
 669
 670                 addr6 = (struct in6_addr*)&neigh->primary_key;
 671                 addr_type = ipv6_addr_type(addr6);
 672
 673                 if (addr_type == IPV6_ADDR_ANY) {
 674                         addr6 = &ipv6_hdr(skb)->daddr;
 675                         addr_type = ipv6_addr_type(addr6);
 676                 }
 677
 678                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 679                         goto tx_error_icmp;
 680
 681                 dst = addr6->s6_addr32[3];
 682         }
 683
 684         {
 685                 struct flowi fl = { .nl_u = { .ip4_u =
 686                                               { .daddr = dst,
 687                                                 .saddr = tiph->saddr,
 688                                                 .tos = RT_TOS(tos) } },
 689                                     .oif = tunnel->parms.link,
 690                                     .proto = IPPROTO_IPV6 };
 691                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 692                         stats->tx_carrier_errors++;
 693                         goto tx_error_icmp;
 694                 }
 695         }
 696         if (rt->rt_type != RTN_UNICAST) {
 697                 ip_rt_put(rt);
 698                 stats->tx_carrier_errors++;
 699                 goto tx_error_icmp;
 700         }
 701         tdev = rt->u.dst.dev;
 702
 703         if (tdev == dev) {
 704                 ip_rt_put(rt);
 705                 stats->collisions++;
 706                 goto tx_error;
 707         }
 708
 709         if (tiph->frag_off)
 710                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 711         else
 712                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 713
 714         if (mtu < 68) {
 715                 stats->collisions++;
 716                 ip_rt_put(rt);
 717                 goto tx_error;
 718         }
 719         if (mtu < IPV6_MIN_MTU)
 720                 mtu = IPV6_MIN_MTU;
 721         if (tunnel->parms.iph.daddr && skb_dst(skb))
 722                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 723
 724         if (skb->len > mtu) {
 725                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 726                 ip_rt_put(rt);
 727                 goto tx_error;
 728         }
 729
 730         if (tunnel->err_count > 0) {
 731                 if (time_before(jiffies,
 732                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 733                         tunnel->err_count--;
 734                         dst_link_failure(skb);
 735                 } else
 736                         tunnel->err_count = 0;
 737         }
 738
 739         /*
 740          * Okay, now see if we can stuff it in the buffer as-is.
 741          */
 742         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 743
 744         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 745             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 746                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 747                 if (!new_skb) {
 748                         ip_rt_put(rt);
 749                         stats->tx_dropped++;
 750                         dev_kfree_skb(skb);
 751                         return NETDEV_TX_OK;
 752                 }
 753                 if (skb->sk)
 754                         skb_set_owner_w(new_skb, skb->sk);
 755                 dev_kfree_skb(skb);
 756                 skb = new_skb;
 757                 iph6 = ipv6_hdr(skb);
 758         }
 759
 760         skb->transport_header = skb->network_header;
 761         skb_push(skb, sizeof(struct iphdr));
 762         skb_reset_network_header(skb);
 763         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 764         IPCB(skb)->flags = 0;
 765         skb_dst_drop(skb);
 766         skb_dst_set(skb, &rt->u.dst);
 767
 768         /*
 769          *      Push down and install the IPIP header.
 770          */
 771
 772         iph                     =       ip_hdr(skb);
 773         iph->version            =       4;
 774         iph->ihl                =       sizeof(struct iphdr)>>2;
 775         if (mtu > IPV6_MIN_MTU)
 776                 iph->frag_off   =       tiph->frag_off;
 777         else
 778                 iph->frag_off   =       0;
 779
 780         iph->protocol           =       IPPROTO_IPV6;
 781         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 782         iph->daddr              =       rt->rt_dst;
 783         iph->saddr              =       rt->rt_src;
 784
 785         if ((iph->ttl = tiph->ttl) == 0)
 786                 iph->ttl        =       iph6->hop_limit;
 787
 788         nf_reset(skb);
 789
 790         IPTUNNEL_XMIT();
 791         return NETDEV_TX_OK;
 792
 793 tx_error_icmp:
 794         dst_link_failure(skb);
 795 tx_error:
 796         stats->tx_errors++;
 797         dev_kfree_skb(skb);
 798         return NETDEV_TX_OK;
 799 }
 800
 801 static void ipip6_tunnel_bind_dev(struct net_device *dev)
 802 {
 803         struct net_device *tdev = NULL;
 804         struct ip_tunnel *tunnel;
 805         struct iphdr *iph;
 806
 807         tunnel = netdev_priv(dev);
 808         iph = &tunnel->parms.iph;
 809
 810         if (iph->daddr) {
 811                 struct flowi fl = { .nl_u = { .ip4_u =
 812                                               { .daddr = iph->daddr,
 813                                                 .saddr = iph->saddr,
 814                                                 .tos = RT_TOS(iph->tos) } },
 815                                     .oif = tunnel->parms.link,
 816                                     .proto = IPPROTO_IPV6 };
 817                 struct rtable *rt;
 818                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 819                         tdev = rt->u.dst.dev;
 820                         ip_rt_put(rt);
 821                 }
 822                 dev->flags |= IFF_POINTOPOINT;
 823         }
 824
 825         if (!tdev && tunnel->parms.link)
 826                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 827
 828         if (tdev) {
 829                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 830                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 831                 if (dev->mtu < IPV6_MIN_MTU)
 832                         dev->mtu = IPV6_MIN_MTU;
 833         }
 834         dev->iflink = tunnel->parms.link;
 835 }
 836
 837 static int
 838 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 839 {
 840         int err = 0;
 841         struct ip_tunnel_parm p;
 842         struct ip_tunnel_prl prl;
 843         struct ip_tunnel *t;
 844         struct net *net = dev_net(dev);
 845         struct sit_net *sitn = net_generic(net, sit_net_id);
 846
 847         switch (cmd) {
 848         case SIOCGETTUNNEL:
 849                 t = NULL;
 850                 if (dev == sitn->fb_tunnel_dev) {
 851                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 852                                 err = -EFAULT;
 853                                 break;
 854                         }
 855                         t = ipip6_tunnel_locate(net, &p, 0);
 856                 }
 857                 if (t == NULL)
 858                         t = netdev_priv(dev);
 859                 memcpy(&p, &t->parms, sizeof(p));
 860                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 861                         err = -EFAULT;
 862                 break;
 863
 864         case SIOCADDTUNNEL:
 865         case SIOCCHGTUNNEL:
 866                 err = -EPERM;
 867                 if (!capable(CAP_NET_ADMIN))
 868                         goto done;
 869
 870                 err = -EFAULT;
 871                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 872                         goto done;
 873
 874                 err = -EINVAL;
 875                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 876                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 877                         goto done;
 878                 if (p.iph.ttl)
 879                         p.iph.frag_off |= htons(IP_DF);
 880
 881                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 882
 883                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 884                         if (t != NULL) {
 885                                 if (t->dev != dev) {
 886                                         err = -EEXIST;
 887                                         break;
 888                                 }
 889                         } else {
 890                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 891                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 892                                         err = -EINVAL;
 893                                         break;
 894                                 }
 895                                 t = netdev_priv(dev);
 896                                 ipip6_tunnel_unlink(sitn, t);
 897                                 t->parms.iph.saddr = p.iph.saddr;
 898                                 t->parms.iph.daddr = p.iph.daddr;
 899                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 900                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 901                                 ipip6_tunnel_link(sitn, t);
 902                                 netdev_state_change(dev);
 903                         }
 904                 }
 905
 906                 if (t) {
 907                         err = 0;
 908                         if (cmd == SIOCCHGTUNNEL) {
 909                                 t->parms.iph.ttl = p.iph.ttl;
 910                                 t->parms.iph.tos = p.iph.tos;
 911                                 if (t->parms.link != p.link) {
 912                                         t->parms.link = p.link;
 913                                         ipip6_tunnel_bind_dev(dev);
 914                                         netdev_state_change(dev);
 915                                 }
 916                         }
 917                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 918                                 err = -EFAULT;
 919                 } else
 920                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 921                 break;
 922
 923         case SIOCDELTUNNEL:
 924                 err = -EPERM;
 925                 if (!capable(CAP_NET_ADMIN))
 926                         goto done;
 927
 928                 if (dev == sitn->fb_tunnel_dev) {
 929                         err = -EFAULT;
 930                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 931                                 goto done;
 932                         err = -ENOENT;
 933                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 934                                 goto done;
 935                         err = -EPERM;
 936                         if (t == netdev_priv(sitn->fb_tunnel_dev))
 937                                 goto done;
 938                         dev = t->dev;
 939                 }
 940                 unregister_netdevice(dev);
 941                 err = 0;
 942                 break;
 943
 944         case SIOCGETPRL:
 945                 err = -EINVAL;
 946                 if (dev == sitn->fb_tunnel_dev)
 947                         goto done;
 948                 err = -ENOENT;
 949                 if (!(t = netdev_priv(dev)))
 950                         goto done;
 951                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
 952                 break;
 953
 954         case SIOCADDPRL:
 955         case SIOCDELPRL:
 956         case SIOCCHGPRL:
 957                 err = -EPERM;
 958                 if (!capable(CAP_NET_ADMIN))
 959                         goto done;
 960                 err = -EINVAL;
 961                 if (dev == sitn->fb_tunnel_dev)
 962                         goto done;
 963                 err = -EFAULT;
 964                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
 965                         goto done;
 966                 err = -ENOENT;
 967                 if (!(t = netdev_priv(dev)))
 968                         goto done;
 969
 970                 switch (cmd) {
 971                 case SIOCDELPRL:
 972                         err = ipip6_tunnel_del_prl(t, &prl);
 973                         break;
 974                 case SIOCADDPRL:
 975                 case SIOCCHGPRL:
 976                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
 977                         break;
 978                 }
 979                 netdev_state_change(dev);
 980                 break;
 981
 982         default:
 983                 err = -EINVAL;
 984         }
 985
 986 done:
 987         return err;
 988 }
 989
 990 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 991 {
 992         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 993                 return -EINVAL;
 994         dev->mtu = new_mtu;
 995         return 0;
 996 }
 997
 998 static const struct net_device_ops ipip6_netdev_ops = {
 999         .ndo_uninit     = ipip6_tunnel_uninit,
1000         .ndo_start_xmit = ipip6_tunnel_xmit,
1001         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1002         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1003 };
1004
1005 static void ipip6_tunnel_setup(struct net_device *dev)
1006 {
1007         dev->netdev_ops         = &ipip6_netdev_ops;
1008         dev->destructor         = free_netdev;
1009
1010         dev->type               = ARPHRD_SIT;
1011         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1012         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1013         dev->flags              = IFF_NOARP;
1014         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1015         dev->iflink             = 0;
1016         dev->addr_len           = 4;
1017         dev->features           |= NETIF_F_NETNS_LOCAL;
1018 }
1019
1020 static void ipip6_tunnel_init(struct net_device *dev)
1021 {
1022         struct ip_tunnel *tunnel = netdev_priv(dev);
1023
1024         tunnel->dev = dev;
1025         strcpy(tunnel->parms.name, dev->name);
1026
1027         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1028         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1029
1030         ipip6_tunnel_bind_dev(dev);
1031 }
1032
1033 static void ipip6_fb_tunnel_init(struct net_device *dev)
1034 {
1035         struct ip_tunnel *tunnel = netdev_priv(dev);
1036         struct iphdr *iph = &tunnel->parms.iph;
1037         struct net *net = dev_net(dev);
1038         struct sit_net *sitn = net_generic(net, sit_net_id);
1039
1040         tunnel->dev = dev;
1041         strcpy(tunnel->parms.name, dev->name);
1042
1043         iph->version            = 4;
1044         iph->protocol           = IPPROTO_IPV6;
1045         iph->ihl                = 5;
1046         iph->ttl                = 64;
1047
1048         dev_hold(dev);
1049         sitn->tunnels_wc[0]     = tunnel;
1050 }
1051
1052 static struct xfrm_tunnel sit_handler = {
1053         .handler        =       ipip6_rcv,
1054         .err_handler    =       ipip6_err,
1055         .priority       =       1,
1056 };
1057
1058 static void sit_destroy_tunnels(struct sit_net *sitn)
1059 {
1060         int prio;
1061
1062         for (prio = 1; prio < 4; prio++) {
1063                 int h;
1064                 for (h = 0; h < HASH_SIZE; h++) {
1065                         struct ip_tunnel *t;
1066                         while ((t = sitn->tunnels[prio][h]) != NULL)
1067                                 unregister_netdevice(t->dev);
1068                 }
1069         }
1070 }
1071
1072 static int sit_init_net(struct net *net)
1073 {
1074         int err;
1075         struct sit_net *sitn;
1076
1077         err = -ENOMEM;
1078         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1079         if (sitn == NULL)
1080                 goto err_alloc;
1081
1082         err = net_assign_generic(net, sit_net_id, sitn);
1083         if (err < 0)
1084                 goto err_assign;
1085
1086         sitn->tunnels[0] = sitn->tunnels_wc;
1087         sitn->tunnels[1] = sitn->tunnels_l;
1088         sitn->tunnels[2] = sitn->tunnels_r;
1089         sitn->tunnels[3] = sitn->tunnels_r_l;
1090
1091         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1092                                            ipip6_tunnel_setup);
1093         if (!sitn->fb_tunnel_dev) {
1094                 err = -ENOMEM;
1095                 goto err_alloc_dev;
1096         }
1097         dev_net_set(sitn->fb_tunnel_dev, net);
1098
1099         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1100
1101         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1102                 goto err_reg_dev;
1103
1104         return 0;
1105
1106 err_reg_dev:
1107         dev_put(sitn->fb_tunnel_dev);
1108         free_netdev(sitn->fb_tunnel_dev);
1109 err_alloc_dev:
1110         /* nothing */
1111 err_assign:
1112         kfree(sitn);
1113 err_alloc:
1114         return err;
1115 }
1116
1117 static void sit_exit_net(struct net *net)
1118 {
1119         struct sit_net *sitn;
1120
1121         sitn = net_generic(net, sit_net_id);
1122         rtnl_lock();
1123         sit_destroy_tunnels(sitn);
1124         unregister_netdevice(sitn->fb_tunnel_dev);
1125         rtnl_unlock();
1126         kfree(sitn);
1127 }
1128
1129 static struct pernet_operations sit_net_ops = {
1130         .init = sit_init_net,
1131         .exit = sit_exit_net,
1132 };
1133
1134 static void __exit sit_cleanup(void)
1135 {
1136         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1137
1138         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1139 }
1140
1141 static int __init sit_init(void)
1142 {
1143         int err;
1144
1145         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1146
1147         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1148                 printk(KERN_INFO "sit init: Can't add protocol\n");
1149                 return -EAGAIN;
1150         }
1151
1152         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1153         if (err < 0)
1154                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1155
1156         return err;
1157 }
1158
1159 module_init(sit_init);
1160 module_exit(sit_cleanup);
1161 MODULE_LICENSE("GPL");
1162 MODULE_ALIAS("sit0");