net/ipv6/ip6_tunnel.c

   1 /*
   2  *      IPv6 over IPv6 tunnel device
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Ville Nuorvala          <vnuorval@tcs.hut.fi>
   7  *
   8  *      $Id$
   9  *
  10  *      Based on:
  11  *      linux/net/ipv6/sit.c
  12  *
  13  *      RFC 2473
  14  *
  15  *      This program is free software; you can redistribute it and/or
  16  *      modify it under the terms of the GNU General Public License
  17  *      as published by the Free Software Foundation; either version
  18  *      2 of the License, or (at your option) any later version.
  19  *
  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/sockios.h>
  27 #include <linux/if.h>
  28 #include <linux/in.h>
  29 #include <linux/ip.h>
  30 #include <linux/if_tunnel.h>
  31 #include <linux/net.h>
  32 #include <linux/in6.h>
  33 #include <linux/netdevice.h>
  34 #include <linux/if_arp.h>
  35 #include <linux/icmpv6.h>
  36 #include <linux/init.h>
  37 #include <linux/route.h>
  38 #include <linux/rtnetlink.h>
  39 #include <linux/netfilter_ipv6.h>
  40
  41 #include <asm/uaccess.h>
  42 #include <asm/atomic.h>
  43
  44 #include <net/ip.h>
  45 #include <net/ipv6.h>
  46 #include <net/ip6_route.h>
  47 #include <net/addrconf.h>
  48 #include <net/ip6_tunnel.h>
  49 #include <net/xfrm.h>
  50 #include <net/dsfield.h>
  51 #include <net/inet_ecn.h>
  52
  53 MODULE_AUTHOR("Ville Nuorvala");
  54 MODULE_DESCRIPTION("IPv6-in-IPv6 tunnel");
  55 MODULE_LICENSE("GPL");
  56
  57 #define IPV6_TLV_TEL_DST_SIZE 8
  58
  59 #ifdef IP6_TNL_DEBUG
  60 #define IP6_TNL_TRACE(x...) printk(KERN_DEBUG "%s:" x "\n", __FUNCTION__)
  61 #else
  62 #define IP6_TNL_TRACE(x...) do {;} while(0)
  63 #endif
  64
  65 #define IPV6_TCLASS_MASK (IPV6_FLOWINFO_MASK & ~IPV6_FLOWLABEL_MASK)
  66
  67 #define HASH_SIZE  32
  68
  69 #define HASH(addr) (((addr)->s6_addr32[0] ^ (addr)->s6_addr32[1] ^ \
  70                      (addr)->s6_addr32[2] ^ (addr)->s6_addr32[3]) & \
  71                     (HASH_SIZE - 1))
  72
  73 static int ip6ip6_fb_tnl_dev_init(struct net_device *dev);
  74 static int ip6ip6_tnl_dev_init(struct net_device *dev);
  75 static void ip6ip6_tnl_dev_setup(struct net_device *dev);
  76
  77 /* the IPv6 tunnel fallback device */
  78 static struct net_device *ip6ip6_fb_tnl_dev;
  79
  80
  81 /* lists for storing tunnels in use */
  82 static struct ip6_tnl *tnls_r_l[HASH_SIZE];
  83 static struct ip6_tnl *tnls_wc[1];
  84 static struct ip6_tnl **tnls[2] = { tnls_wc, tnls_r_l };
  85
  86 /* lock for the tunnel lists */
  87 static DEFINE_RWLOCK(ip6ip6_lock);
  88
  89 static inline struct dst_entry *ip6_tnl_dst_check(struct ip6_tnl *t)
  90 {
  91         struct dst_entry *dst = t->dst_cache;
  92
  93         if (dst && dst->obsolete &&
  94             dst->ops->check(dst, t->dst_cookie) == NULL) {
  95                 t->dst_cache = NULL;
  96                 dst_release(dst);
  97                 return NULL;
  98         }
  99
 100         return dst;
 101 }
 102
 103 static inline void ip6_tnl_dst_reset(struct ip6_tnl *t)
 104 {
 105         dst_release(t->dst_cache);
 106         t->dst_cache = NULL;
 107 }
 108
 109 static inline void ip6_tnl_dst_store(struct ip6_tnl *t, struct dst_entry *dst)
 110 {
 111         struct rt6_info *rt = (struct rt6_info *) dst;
 112         t->dst_cookie = rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;
 113         dst_release(t->dst_cache);
 114         t->dst_cache = dst;
 115 }
 116
 117 /**
 118  * ip6ip6_tnl_lookup - fetch tunnel matching the end-point addresses
 119  *   @remote: the address of the tunnel exit-point
 120  *   @local: the address of the tunnel entry-point
 121  *
 122  * Return:
 123  *   tunnel matching given end-points if found,
 124  *   else fallback tunnel if its device is up,
 125  *   else %NULL
 126  **/
 127
 128 static struct ip6_tnl *
 129 ip6ip6_tnl_lookup(struct in6_addr *remote, struct in6_addr *local)
 130 {
 131         unsigned h0 = HASH(remote);
 132         unsigned h1 = HASH(local);
 133         struct ip6_tnl *t;
 134
 135         for (t = tnls_r_l[h0 ^ h1]; t; t = t->next) {
 136                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
 137                     ipv6_addr_equal(remote, &t->parms.raddr) &&
 138                     (t->dev->flags & IFF_UP))
 139                         return t;
 140         }
 141         if ((t = tnls_wc[0]) != NULL && (t->dev->flags & IFF_UP))
 142                 return t;
 143
 144         return NULL;
 145 }
 146
 147 /**
 148  * ip6ip6_bucket - get head of list matching given tunnel parameters
 149  *   @p: parameters containing tunnel end-points
 150  *
 151  * Description:
 152  *   ip6ip6_bucket() returns the head of the list matching the
 153  *   &struct in6_addr entries laddr and raddr in @p.
 154  *
 155  * Return: head of IPv6 tunnel list
 156  **/
 157
 158 static struct ip6_tnl **
 159 ip6ip6_bucket(struct ip6_tnl_parm *p)
 160 {
 161         struct in6_addr *remote = &p->raddr;
 162         struct in6_addr *local = &p->laddr;
 163         unsigned h = 0;
 164         int prio = 0;
 165
 166         if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
 167                 prio = 1;
 168                 h = HASH(remote) ^ HASH(local);
 169         }
 170         return &tnls[prio][h];
 171 }
 172
 173 /**
 174  * ip6ip6_tnl_link - add tunnel to hash table
 175  *   @t: tunnel to be added
 176  **/
 177
 178 static void
 179 ip6ip6_tnl_link(struct ip6_tnl *t)
 180 {
 181         struct ip6_tnl **tp = ip6ip6_bucket(&t->parms);
 182
 183         t->next = *tp;
 184         write_lock_bh(&ip6ip6_lock);
 185         *tp = t;
 186         write_unlock_bh(&ip6ip6_lock);
 187 }
 188
 189 /**
 190  * ip6ip6_tnl_unlink - remove tunnel from hash table
 191  *   @t: tunnel to be removed
 192  **/
 193
 194 static void
 195 ip6ip6_tnl_unlink(struct ip6_tnl *t)
 196 {
 197         struct ip6_tnl **tp;
 198
 199         for (tp = ip6ip6_bucket(&t->parms); *tp; tp = &(*tp)->next) {
 200                 if (t == *tp) {
 201                         write_lock_bh(&ip6ip6_lock);
 202                         *tp = t->next;
 203                         write_unlock_bh(&ip6ip6_lock);
 204                         break;
 205                 }
 206         }
 207 }
 208
 209 /**
 210  * ip6_tnl_create() - create a new tunnel
 211  *   @p: tunnel parameters
 212  *   @pt: pointer to new tunnel
 213  *
 214  * Description:
 215  *   Create tunnel matching given parameters.
 216  *
 217  * Return:
 218  *   0 on success
 219  **/
 220
 221 static int
 222 ip6_tnl_create(struct ip6_tnl_parm *p, struct ip6_tnl **pt)
 223 {
 224         struct net_device *dev;
 225         struct ip6_tnl *t;
 226         char name[IFNAMSIZ];
 227         int err;
 228
 229         if (p->name[0]) {
 230                 strlcpy(name, p->name, IFNAMSIZ);
 231         } else {
 232                 int i;
 233                 for (i = 1; i < IP6_TNL_MAX; i++) {
 234                         sprintf(name, "ip6tnl%d", i);
 235                         if (__dev_get_by_name(name) == NULL)
 236                                 break;
 237                 }
 238                 if (i == IP6_TNL_MAX)
 239                         return -ENOBUFS;
 240         }
 241         dev = alloc_netdev(sizeof (*t), name, ip6ip6_tnl_dev_setup);
 242         if (dev == NULL)
 243                 return -ENOMEM;
 244
 245         t = netdev_priv(dev);
 246         dev->init = ip6ip6_tnl_dev_init;
 247         t->parms = *p;
 248
 249         if ((err = register_netdevice(dev)) < 0) {
 250                 free_netdev(dev);
 251                 return err;
 252         }
 253         dev_hold(dev);
 254
 255         ip6ip6_tnl_link(t);
 256         *pt = t;
 257         return 0;
 258 }
 259
 260 /**
 261  * ip6ip6_tnl_locate - find or create tunnel matching given parameters
 262  *   @p: tunnel parameters
 263  *   @create: != 0 if allowed to create new tunnel if no match found
 264  *
 265  * Description:
 266  *   ip6ip6_tnl_locate() first tries to locate an existing tunnel
 267  *   based on @parms. If this is unsuccessful, but @create is set a new
 268  *   tunnel device is created and registered for use.
 269  *
 270  * Return:
 271  *   0 if tunnel located or created,
 272  *   -EINVAL if parameters incorrect,
 273  *   -ENODEV if no matching tunnel available
 274  **/
 275
 276 static int
 277 ip6ip6_tnl_locate(struct ip6_tnl_parm *p, struct ip6_tnl **pt, int create)
 278 {
 279         struct in6_addr *remote = &p->raddr;
 280         struct in6_addr *local = &p->laddr;
 281         struct ip6_tnl *t;
 282
 283         if (p->proto != IPPROTO_IPV6)
 284                 return -EINVAL;
 285
 286         for (t = *ip6ip6_bucket(p); t; t = t->next) {
 287                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
 288                     ipv6_addr_equal(remote, &t->parms.raddr)) {
 289                         *pt = t;
 290                         return (create ? -EEXIST : 0);
 291                 }
 292         }
 293         if (!create)
 294                 return -ENODEV;
 295
 296         return ip6_tnl_create(p, pt);
 297 }
 298
 299 /**
 300  * ip6ip6_tnl_dev_uninit - tunnel device uninitializer
 301  *   @dev: the device to be destroyed
 302  *
 303  * Description:
 304  *   ip6ip6_tnl_dev_uninit() removes tunnel from its list
 305  **/
 306
 307 static void
 308 ip6ip6_tnl_dev_uninit(struct net_device *dev)
 309 {
 310         struct ip6_tnl *t = netdev_priv(dev);
 311
 312         if (dev == ip6ip6_fb_tnl_dev) {
 313                 write_lock_bh(&ip6ip6_lock);
 314                 tnls_wc[0] = NULL;
 315                 write_unlock_bh(&ip6ip6_lock);
 316         } else {
 317                 ip6ip6_tnl_unlink(t);
 318         }
 319         ip6_tnl_dst_reset(t);
 320         dev_put(dev);
 321 }
 322
 323 /**
 324  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
 325  *   @skb: received socket buffer
 326  *
 327  * Return:
 328  *   0 if none was found,
 329  *   else index to encapsulation limit
 330  **/
 331
 332 static __u16
 333 parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw)
 334 {
 335         struct ipv6hdr *ipv6h = (struct ipv6hdr *) raw;
 336         __u8 nexthdr = ipv6h->nexthdr;
 337         __u16 off = sizeof (*ipv6h);
 338
 339         while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
 340                 __u16 optlen = 0;
 341                 struct ipv6_opt_hdr *hdr;
 342                 if (raw + off + sizeof (*hdr) > skb->data &&
 343                     !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
 344                         break;
 345
 346                 hdr = (struct ipv6_opt_hdr *) (raw + off);
 347                 if (nexthdr == NEXTHDR_FRAGMENT) {
 348                         struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
 349                         if (frag_hdr->frag_off)
 350                                 break;
 351                         optlen = 8;
 352                 } else if (nexthdr == NEXTHDR_AUTH) {
 353                         optlen = (hdr->hdrlen + 2) << 2;
 354                 } else {
 355                         optlen = ipv6_optlen(hdr);
 356                 }
 357                 if (nexthdr == NEXTHDR_DEST) {
 358                         __u16 i = off + 2;
 359                         while (1) {
 360                                 struct ipv6_tlv_tnl_enc_lim *tel;
 361
 362                                 /* No more room for encapsulation limit */
 363                                 if (i + sizeof (*tel) > off + optlen)
 364                                         break;
 365
 366                                 tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
 367                                 /* return index of option if found and valid */
 368                                 if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
 369                                     tel->length == 1)
 370                                         return i;
 371                                 /* else jump to next option */
 372                                 if (tel->type)
 373                                         i += tel->length + 2;
 374                                 else
 375                                         i++;
 376                         }
 377                 }
 378                 nexthdr = hdr->nexthdr;
 379                 off += optlen;
 380         }
 381         return 0;
 382 }
 383
 384 /**
 385  * ip6ip6_err - tunnel error handler
 386  *
 387  * Description:
 388  *   ip6ip6_err() should handle errors in the tunnel according
 389  *   to the specifications in RFC 2473.
 390  **/
 391
 392 static int
 393 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 394            int type, int code, int offset, __u32 info)
 395 {
 396         struct ipv6hdr *ipv6h = (struct ipv6hdr *) skb->data;
 397         struct ip6_tnl *t;
 398         int rel_msg = 0;
 399         int rel_type = ICMPV6_DEST_UNREACH;
 400         int rel_code = ICMPV6_ADDR_UNREACH;
 401         __u32 rel_info = 0;
 402         __u16 len;
 403         int err = -ENOENT;
 404
 405         /* If the packet doesn't contain the original IPv6 header we are
 406            in trouble since we might need the source address for further
 407            processing of the error. */
 408
 409         read_lock(&ip6ip6_lock);
 410         if ((t = ip6ip6_tnl_lookup(&ipv6h->daddr, &ipv6h->saddr)) == NULL)
 411                 goto out;
 412
 413         err = 0;
 414
 415         switch (type) {
 416                 __u32 teli;
 417                 struct ipv6_tlv_tnl_enc_lim *tel;
 418                 __u32 mtu;
 419         case ICMPV6_DEST_UNREACH:
 420                 if (net_ratelimit())
 421                         printk(KERN_WARNING
 422                                "%s: Path to destination invalid "
 423                                "or inactive!\n", t->parms.name);
 424                 rel_msg = 1;
 425                 break;
 426         case ICMPV6_TIME_EXCEED:
 427                 if (code == ICMPV6_EXC_HOPLIMIT) {
 428                         if (net_ratelimit())
 429                                 printk(KERN_WARNING
 430                                        "%s: Too small hop limit or "
 431                                        "routing loop in tunnel!\n",
 432                                        t->parms.name);
 433                         rel_msg = 1;
 434                 }
 435                 break;
 436         case ICMPV6_PARAMPROB:
 437                 /* ignore if parameter problem not caused by a tunnel
 438                    encapsulation limit sub-option */
 439                 if (code != ICMPV6_HDR_FIELD) {
 440                         break;
 441                 }
 442                 teli = parse_tlv_tnl_enc_lim(skb, skb->data);
 443
 444                 if (teli && teli == ntohl(info) - 2) {
 445                         tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
 446                         if (tel->encap_limit == 0) {
 447                                 if (net_ratelimit())
 448                                         printk(KERN_WARNING
 449                                                "%s: Too small encapsulation "
 450                                                "limit or routing loop in "
 451                                                "tunnel!\n", t->parms.name);
 452                                 rel_msg = 1;
 453                         }
 454                 }
 455                 break;
 456         case ICMPV6_PKT_TOOBIG:
 457                 mtu = ntohl(info) - offset;
 458                 if (mtu < IPV6_MIN_MTU)
 459                         mtu = IPV6_MIN_MTU;
 460                 t->dev->mtu = mtu;
 461
 462                 if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
 463                         rel_type = ICMPV6_PKT_TOOBIG;
 464                         rel_code = 0;
 465                         rel_info = mtu;
 466                         rel_msg = 1;
 467                 }
 468                 break;
 469         }
 470         if (rel_msg &&  pskb_may_pull(skb, offset + sizeof (*ipv6h))) {
 471                 struct rt6_info *rt;
 472                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 473                 if (!skb2)
 474                         goto out;
 475
 476                 dst_release(skb2->dst);
 477                 skb2->dst = NULL;
 478                 skb_pull(skb2, offset);
 479                 skb2->nh.raw = skb2->data;
 480
 481                 /* Try to guess incoming interface */
 482                 rt = rt6_lookup(&skb2->nh.ipv6h->saddr, NULL, 0, 0);
 483
 484                 if (rt && rt->rt6i_dev)
 485                         skb2->dev = rt->rt6i_dev;
 486
 487                 icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
 488
 489                 if (rt)
 490                         dst_release(&rt->u.dst);
 491
 492                 kfree_skb(skb2);
 493         }
 494 out:
 495         read_unlock(&ip6ip6_lock);
 496         return err;
 497 }
 498
 499 static inline void ip6ip6_ecn_decapsulate(struct ipv6hdr *outer_iph,
 500                                           struct sk_buff *skb)
 501 {
 502         struct ipv6hdr *inner_iph = skb->nh.ipv6h;
 503
 504         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
 505                 IP6_ECN_set_ce(inner_iph);
 506 }
 507
 508 /**
 509  * ip6ip6_rcv - decapsulate IPv6 packet and retransmit it locally
 510  *   @skb: received socket buffer
 511  *
 512  * Return: 0
 513  **/
 514
 515 static int
 516 ip6ip6_rcv(struct sk_buff *skb)
 517 {
 518         struct ipv6hdr *ipv6h;
 519         struct ip6_tnl *t;
 520
 521         ipv6h = skb->nh.ipv6h;
 522
 523         read_lock(&ip6ip6_lock);
 524
 525         if ((t = ip6ip6_tnl_lookup(&ipv6h->saddr, &ipv6h->daddr)) != NULL) {
 526                 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 527                         read_unlock(&ip6ip6_lock);
 528                         goto discard;
 529                 }
 530
 531                 if (!(t->parms.flags & IP6_TNL_F_CAP_RCV)) {
 532                         t->stat.rx_dropped++;
 533                         read_unlock(&ip6ip6_lock);
 534                         goto discard;
 535                 }
 536                 secpath_reset(skb);
 537                 skb->mac.raw = skb->nh.raw;
 538                 skb->nh.raw = skb->data;
 539                 skb->protocol = htons(ETH_P_IPV6);
 540                 skb->pkt_type = PACKET_HOST;
 541                 memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
 542                 skb->dev = t->dev;
 543                 dst_release(skb->dst);
 544                 skb->dst = NULL;
 545                 if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
 546                         ipv6_copy_dscp(ipv6h, skb->nh.ipv6h);
 547                 ip6ip6_ecn_decapsulate(ipv6h, skb);
 548                 t->stat.rx_packets++;
 549                 t->stat.rx_bytes += skb->len;
 550                 netif_rx(skb);
 551                 read_unlock(&ip6ip6_lock);
 552                 return 0;
 553         }
 554         read_unlock(&ip6ip6_lock);
 555         return 1;
 556
 557 discard:
 558         kfree_skb(skb);
 559         return 0;
 560 }
 561
 562 static inline struct ipv6_txoptions *create_tel(__u8 encap_limit)
 563 {
 564         struct ipv6_tlv_tnl_enc_lim *tel;
 565         struct ipv6_txoptions *opt;
 566         __u8 *raw;
 567
 568         int opt_len = sizeof(*opt) + 8;
 569
 570         if (!(opt = kzalloc(opt_len, GFP_ATOMIC))) {
 571                 return NULL;
 572         }
 573         opt->tot_len = opt_len;
 574         opt->dst0opt = (struct ipv6_opt_hdr *) (opt + 1);
 575         opt->opt_nflen = 8;
 576
 577         tel = (struct ipv6_tlv_tnl_enc_lim *) (opt->dst0opt + 1);
 578         tel->type = IPV6_TLV_TNL_ENCAP_LIMIT;
 579         tel->length = 1;
 580         tel->encap_limit = encap_limit;
 581
 582         raw = (__u8 *) opt->dst0opt;
 583         raw[5] = IPV6_TLV_PADN;
 584         raw[6] = 1;
 585
 586         return opt;
 587 }
 588
 589 /**
 590  * ip6ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
 591  *   @t: the outgoing tunnel device
 592  *   @hdr: IPv6 header from the incoming packet
 593  *
 594  * Description:
 595  *   Avoid trivial tunneling loop by checking that tunnel exit-point
 596  *   doesn't match source of incoming packet.
 597  *
 598  * Return:
 599  *   1 if conflict,
 600  *   0 else
 601  **/
 602
 603 static inline int
 604 ip6ip6_tnl_addr_conflict(struct ip6_tnl *t, struct ipv6hdr *hdr)
 605 {
 606         return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
 607 }
 608
 609 /**
 610  * ip6ip6_tnl_xmit - encapsulate packet and send
 611  *   @skb: the outgoing socket buffer
 612  *   @dev: the outgoing tunnel device
 613  *
 614  * Description:
 615  *   Build new header and do some sanity checks on the packet before sending
 616  *   it.
 617  *
 618  * Return:
 619  *   0
 620  **/
 621
 622 static int
 623 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 624 {
 625         struct ip6_tnl *t = netdev_priv(dev);
 626         struct net_device_stats *stats = &t->stat;
 627         struct ipv6hdr *ipv6h = skb->nh.ipv6h;
 628         struct ipv6_txoptions *opt = NULL;
 629         int encap_limit = -1;
 630         __u16 offset;
 631         struct flowi fl;
 632         struct dst_entry *dst;
 633         struct net_device *tdev;
 634         int mtu;
 635         int max_headroom = sizeof(struct ipv6hdr);
 636         u8 proto;
 637         int err;
 638         int pkt_len;
 639         int dsfield;
 640
 641         if (t->recursion++) {
 642                 stats->collisions++;
 643                 goto tx_err;
 644         }
 645         if (skb->protocol != htons(ETH_P_IPV6) ||
 646             !(t->parms.flags & IP6_TNL_F_CAP_XMIT) ||
 647             ip6ip6_tnl_addr_conflict(t, ipv6h)) {
 648                 goto tx_err;
 649         }
 650         if ((offset = parse_tlv_tnl_enc_lim(skb, skb->nh.raw)) > 0) {
 651                 struct ipv6_tlv_tnl_enc_lim *tel;
 652                 tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->nh.raw[offset];
 653                 if (tel->encap_limit == 0) {
 654                         icmpv6_send(skb, ICMPV6_PARAMPROB,
 655                                     ICMPV6_HDR_FIELD, offset + 2, skb->dev);
 656                         goto tx_err;
 657                 }
 658                 encap_limit = tel->encap_limit - 1;
 659         } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT)) {
 660                 encap_limit = t->parms.encap_limit;
 661         }
 662         memcpy(&fl, &t->fl, sizeof (fl));
 663         proto = fl.proto;
 664
 665         dsfield = ipv6_get_dsfield(ipv6h);
 666         if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
 667                 fl.fl6_flowlabel |= (*(__u32 *) ipv6h & IPV6_TCLASS_MASK);
 668         if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
 669                 fl.fl6_flowlabel |= (*(__u32 *) ipv6h & IPV6_FLOWLABEL_MASK);
 670
 671         if (encap_limit >= 0 && (opt = create_tel(encap_limit)) == NULL)
 672                 goto tx_err;
 673
 674         if ((dst = ip6_tnl_dst_check(t)) != NULL)
 675                 dst_hold(dst);
 676         else {
 677                 dst = ip6_route_output(NULL, &fl);
 678
 679                 if (dst->error || xfrm_lookup(&dst, &fl, NULL, 0) < 0)
 680                         goto tx_err_link_failure;
 681         }
 682
 683         tdev = dst->dev;
 684
 685         if (tdev == dev) {
 686                 stats->collisions++;
 687                 if (net_ratelimit())
 688                         printk(KERN_WARNING
 689                                "%s: Local routing loop detected!\n",
 690                                t->parms.name);
 691                 goto tx_err_dst_release;
 692         }
 693         mtu = dst_mtu(dst) - sizeof (*ipv6h);
 694         if (opt) {
 695                 max_headroom += 8;
 696                 mtu -= 8;
 697         }
 698         if (mtu < IPV6_MIN_MTU)
 699                 mtu = IPV6_MIN_MTU;
 700         if (skb->dst && mtu < dst_mtu(skb->dst)) {
 701                 struct rt6_info *rt = (struct rt6_info *) skb->dst;
 702                 rt->rt6i_flags |= RTF_MODIFIED;
 703                 rt->u.dst.metrics[RTAX_MTU-1] = mtu;
 704         }
 705         if (skb->len > mtu) {
 706                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 707                 goto tx_err_dst_release;
 708         }
 709
 710         /*
 711          * Okay, now see if we can stuff it in the buffer as-is.
 712          */
 713         max_headroom += LL_RESERVED_SPACE(tdev);
 714
 715         if (skb_headroom(skb) < max_headroom ||
 716             skb_cloned(skb) || skb_shared(skb)) {
 717                 struct sk_buff *new_skb;
 718
 719                 if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
 720                         goto tx_err_dst_release;
 721
 722                 if (skb->sk)
 723                         skb_set_owner_w(new_skb, skb->sk);
 724                 kfree_skb(skb);
 725                 skb = new_skb;
 726         }
 727         dst_release(skb->dst);
 728         skb->dst = dst_clone(dst);
 729
 730         skb->h.raw = skb->nh.raw;
 731
 732         if (opt)
 733                 ipv6_push_nfrag_opts(skb, opt, &proto, NULL);
 734
 735         skb->nh.raw = skb_push(skb, sizeof(struct ipv6hdr));
 736         ipv6h = skb->nh.ipv6h;
 737         *(u32*)ipv6h = fl.fl6_flowlabel | htonl(0x60000000);
 738         dsfield = INET_ECN_encapsulate(0, dsfield);
 739         ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
 740         ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 741         ipv6h->hop_limit = t->parms.hop_limit;
 742         ipv6h->nexthdr = proto;
 743         ipv6_addr_copy(&ipv6h->saddr, &fl.fl6_src);
 744         ipv6_addr_copy(&ipv6h->daddr, &fl.fl6_dst);
 745         nf_reset(skb);
 746         pkt_len = skb->len;
 747         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL,
 748                       skb->dst->dev, dst_output);
 749
 750         if (err == NET_XMIT_SUCCESS || err == NET_XMIT_CN) {
 751                 stats->tx_bytes += pkt_len;
 752                 stats->tx_packets++;
 753         } else {
 754                 stats->tx_errors++;
 755                 stats->tx_aborted_errors++;
 756         }
 757         ip6_tnl_dst_store(t, dst);
 758
 759         kfree(opt);
 760
 761         t->recursion--;
 762         return 0;
 763 tx_err_link_failure:
 764         stats->tx_carrier_errors++;
 765         dst_link_failure(skb);
 766 tx_err_dst_release:
 767         dst_release(dst);
 768         kfree(opt);
 769 tx_err:
 770         stats->tx_errors++;
 771         stats->tx_dropped++;
 772         kfree_skb(skb);
 773         t->recursion--;
 774         return 0;
 775 }
 776
 777 static void ip6_tnl_set_cap(struct ip6_tnl *t)
 778 {
 779         struct ip6_tnl_parm *p = &t->parms;
 780         struct in6_addr *laddr = &p->laddr;
 781         struct in6_addr *raddr = &p->raddr;
 782         int ltype = ipv6_addr_type(laddr);
 783         int rtype = ipv6_addr_type(raddr);
 784
 785         p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV);
 786
 787         if (ltype != IPV6_ADDR_ANY && rtype != IPV6_ADDR_ANY &&
 788             ((ltype|rtype) &
 789              (IPV6_ADDR_UNICAST|
 790               IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL|
 791               IPV6_ADDR_MAPPED|IPV6_ADDR_RESERVED)) == IPV6_ADDR_UNICAST) {
 792                 struct net_device *ldev = NULL;
 793                 int l_ok = 1;
 794                 int r_ok = 1;
 795
 796                 if (p->link)
 797                         ldev = dev_get_by_index(p->link);
 798
 799                 if (ltype&IPV6_ADDR_UNICAST && !ipv6_chk_addr(laddr, ldev, 0))
 800                         l_ok = 0;
 801
 802                 if (rtype&IPV6_ADDR_UNICAST && ipv6_chk_addr(raddr, NULL, 0))
 803                         r_ok = 0;
 804
 805                 if (l_ok && r_ok) {
 806                         if (ltype&IPV6_ADDR_UNICAST)
 807                                 p->flags |= IP6_TNL_F_CAP_XMIT;
 808                         if (rtype&IPV6_ADDR_UNICAST)
 809                                 p->flags |= IP6_TNL_F_CAP_RCV;
 810                 }
 811                 if (ldev)
 812                         dev_put(ldev);
 813         }
 814 }
 815
 816 static void ip6ip6_tnl_link_config(struct ip6_tnl *t)
 817 {
 818         struct net_device *dev = t->dev;
 819         struct ip6_tnl_parm *p = &t->parms;
 820         struct flowi *fl = &t->fl;
 821
 822         memcpy(&dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
 823         memcpy(&dev->broadcast, &p->raddr, sizeof(struct in6_addr));
 824
 825         /* Set up flowi template */
 826         ipv6_addr_copy(&fl->fl6_src, &p->laddr);
 827         ipv6_addr_copy(&fl->fl6_dst, &p->raddr);
 828         fl->oif = p->link;
 829         fl->fl6_flowlabel = 0;
 830
 831         if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
 832                 fl->fl6_flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
 833         if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
 834                 fl->fl6_flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
 835
 836         ip6_tnl_set_cap(t);
 837
 838         if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
 839                 dev->flags |= IFF_POINTOPOINT;
 840         else
 841                 dev->flags &= ~IFF_POINTOPOINT;
 842
 843         dev->iflink = p->link;
 844
 845         if (p->flags & IP6_TNL_F_CAP_XMIT) {
 846                 struct rt6_info *rt = rt6_lookup(&p->raddr, &p->laddr,
 847                                                  p->link, 0);
 848
 849                 if (rt == NULL)
 850                         return;
 851
 852                 if (rt->rt6i_dev) {
 853                         dev->hard_header_len = rt->rt6i_dev->hard_header_len +
 854                                 sizeof (struct ipv6hdr);
 855
 856                         dev->mtu = rt->rt6i_dev->mtu - sizeof (struct ipv6hdr);
 857
 858                         if (dev->mtu < IPV6_MIN_MTU)
 859                                 dev->mtu = IPV6_MIN_MTU;
 860                 }
 861                 dst_release(&rt->u.dst);
 862         }
 863 }
 864
 865 /**
 866  * ip6ip6_tnl_change - update the tunnel parameters
 867  *   @t: tunnel to be changed
 868  *   @p: tunnel configuration parameters
 869  *   @active: != 0 if tunnel is ready for use
 870  *
 871  * Description:
 872  *   ip6ip6_tnl_change() updates the tunnel parameters
 873  **/
 874
 875 static int
 876 ip6ip6_tnl_change(struct ip6_tnl *t, struct ip6_tnl_parm *p)
 877 {
 878         ipv6_addr_copy(&t->parms.laddr, &p->laddr);
 879         ipv6_addr_copy(&t->parms.raddr, &p->raddr);
 880         t->parms.flags = p->flags;
 881         t->parms.hop_limit = p->hop_limit;
 882         t->parms.encap_limit = p->encap_limit;
 883         t->parms.flowinfo = p->flowinfo;
 884         t->parms.link = p->link;
 885         ip6_tnl_dst_reset(t);
 886         ip6ip6_tnl_link_config(t);
 887         return 0;
 888 }
 889
 890 /**
 891  * ip6ip6_tnl_ioctl - configure ipv6 tunnels from userspace
 892  *   @dev: virtual device associated with tunnel
 893  *   @ifr: parameters passed from userspace
 894  *   @cmd: command to be performed
 895  *
 896  * Description:
 897  *   ip6ip6_tnl_ioctl() is used for managing IPv6 tunnels
 898  *   from userspace.
 899  *
 900  *   The possible commands are the following:
 901  *     %SIOCGETTUNNEL: get tunnel parameters for device
 902  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
 903  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
 904  *     %SIOCDELTUNNEL: delete tunnel
 905  *
 906  *   The fallback device "ip6tnl0", created during module
 907  *   initialization, can be used for creating other tunnel devices.
 908  *
 909  * Return:
 910  *   0 on success,
 911  *   %-EFAULT if unable to copy data to or from userspace,
 912  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
 913  *   %-EINVAL if passed tunnel parameters are invalid,
 914  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
 915  *   %-ENODEV if attempting to change or delete a nonexisting device
 916  **/
 917
 918 static int
 919 ip6ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 920 {
 921         int err = 0;
 922         int create;
 923         struct ip6_tnl_parm p;
 924         struct ip6_tnl *t = NULL;
 925
 926         switch (cmd) {
 927         case SIOCGETTUNNEL:
 928                 if (dev == ip6ip6_fb_tnl_dev) {
 929                         if (copy_from_user(&p,
 930                                            ifr->ifr_ifru.ifru_data,
 931                                            sizeof (p))) {
 932                                 err = -EFAULT;
 933                                 break;
 934                         }
 935                         if ((err = ip6ip6_tnl_locate(&p, &t, 0)) == -ENODEV)
 936                                 t = netdev_priv(dev);
 937                         else if (err)
 938                                 break;
 939                 } else
 940                         t = netdev_priv(dev);
 941
 942                 memcpy(&p, &t->parms, sizeof (p));
 943                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
 944                         err = -EFAULT;
 945                 }
 946                 break;
 947         case SIOCADDTUNNEL:
 948         case SIOCCHGTUNNEL:
 949                 err = -EPERM;
 950                 create = (cmd == SIOCADDTUNNEL);
 951                 if (!capable(CAP_NET_ADMIN))
 952                         break;
 953                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
 954                         err = -EFAULT;
 955                         break;
 956                 }
 957                 if (!create && dev != ip6ip6_fb_tnl_dev) {
 958                         t = netdev_priv(dev);
 959                 }
 960                 if (!t && (err = ip6ip6_tnl_locate(&p, &t, create))) {
 961                         break;
 962                 }
 963                 if (cmd == SIOCCHGTUNNEL) {
 964                         if (t->dev != dev) {
 965                                 err = -EEXIST;
 966                                 break;
 967                         }
 968                         ip6ip6_tnl_unlink(t);
 969                         err = ip6ip6_tnl_change(t, &p);
 970                         ip6ip6_tnl_link(t);
 971                         netdev_state_change(dev);
 972                 }
 973                 if (copy_to_user(ifr->ifr_ifru.ifru_data,
 974                                  &t->parms, sizeof (p))) {
 975                         err = -EFAULT;
 976                 } else {
 977                         err = 0;
 978                 }
 979                 break;
 980         case SIOCDELTUNNEL:
 981                 err = -EPERM;
 982                 if (!capable(CAP_NET_ADMIN))
 983                         break;
 984
 985                 if (dev == ip6ip6_fb_tnl_dev) {
 986                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data,
 987                                            sizeof (p))) {
 988                                 err = -EFAULT;
 989                                 break;
 990                         }
 991                         err = ip6ip6_tnl_locate(&p, &t, 0);
 992                         if (err)
 993                                 break;
 994                         if (t == netdev_priv(ip6ip6_fb_tnl_dev)) {
 995                                 err = -EPERM;
 996                                 break;
 997                         }
 998                 } else {
 999                         t = netdev_priv(dev);
1000                 }
1001                 err = unregister_netdevice(t->dev);
1002                 break;
1003         default:
1004                 err = -EINVAL;
1005         }
1006         return err;
1007 }
1008
1009 /**
1010  * ip6ip6_tnl_get_stats - return the stats for tunnel device
1011  *   @dev: virtual device associated with tunnel
1012  *
1013  * Return: stats for device
1014  **/
1015
1016 static struct net_device_stats *
1017 ip6ip6_tnl_get_stats(struct net_device *dev)
1018 {
1019         return &(((struct ip6_tnl *)netdev_priv(dev))->stat);
1020 }
1021
1022 /**
1023  * ip6ip6_tnl_change_mtu - change mtu manually for tunnel device
1024  *   @dev: virtual device associated with tunnel
1025  *   @new_mtu: the new mtu
1026  *
1027  * Return:
1028  *   0 on success,
1029  *   %-EINVAL if mtu too small
1030  **/
1031
1032 static int
1033 ip6ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1034 {
1035         if (new_mtu < IPV6_MIN_MTU) {
1036                 return -EINVAL;
1037         }
1038         dev->mtu = new_mtu;
1039         return 0;
1040 }
1041
1042 /**
1043  * ip6ip6_tnl_dev_setup - setup virtual tunnel device
1044  *   @dev: virtual device associated with tunnel
1045  *
1046  * Description:
1047  *   Initialize function pointers and device parameters
1048  **/
1049
1050 static void ip6ip6_tnl_dev_setup(struct net_device *dev)
1051 {
1052         SET_MODULE_OWNER(dev);
1053         dev->uninit = ip6ip6_tnl_dev_uninit;
1054         dev->destructor = free_netdev;
1055         dev->hard_start_xmit = ip6ip6_tnl_xmit;
1056         dev->get_stats = ip6ip6_tnl_get_stats;
1057         dev->do_ioctl = ip6ip6_tnl_ioctl;
1058         dev->change_mtu = ip6ip6_tnl_change_mtu;
1059
1060         dev->type = ARPHRD_TUNNEL6;
1061         dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr);
1062         dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr);
1063         dev->flags |= IFF_NOARP;
1064         dev->addr_len = sizeof(struct in6_addr);
1065 }
1066
1067
1068 /**
1069  * ip6ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1070  *   @dev: virtual device associated with tunnel
1071  **/
1072
1073 static inline void
1074 ip6ip6_tnl_dev_init_gen(struct net_device *dev)
1075 {
1076         struct ip6_tnl *t = netdev_priv(dev);
1077         t->fl.proto = IPPROTO_IPV6;
1078         t->dev = dev;
1079         strcpy(t->parms.name, dev->name);
1080 }
1081
1082 /**
1083  * ip6ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1084  *   @dev: virtual device associated with tunnel
1085  **/
1086
1087 static int
1088 ip6ip6_tnl_dev_init(struct net_device *dev)
1089 {
1090         struct ip6_tnl *t = netdev_priv(dev);
1091         ip6ip6_tnl_dev_init_gen(dev);
1092         ip6ip6_tnl_link_config(t);
1093         return 0;
1094 }
1095
1096 /**
1097  * ip6ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1098  *   @dev: fallback device
1099  *
1100  * Return: 0
1101  **/
1102
1103 static int
1104 ip6ip6_fb_tnl_dev_init(struct net_device *dev)
1105 {
1106         struct ip6_tnl *t = netdev_priv(dev);
1107         ip6ip6_tnl_dev_init_gen(dev);
1108         dev_hold(dev);
1109         tnls_wc[0] = t;
1110         return 0;
1111 }
1112
1113 static struct xfrm6_tunnel ip6ip6_handler = {
1114         .handler        = ip6ip6_rcv,
1115         .err_handler    = ip6ip6_err,
1116         .priority       =       1,
1117 };
1118
1119 /**
1120  * ip6_tunnel_init - register protocol and reserve needed resources
1121  *
1122  * Return: 0 on success
1123  **/
1124
1125 static int __init ip6_tunnel_init(void)
1126 {
1127         int  err;
1128
1129         if (xfrm6_tunnel_register(&ip6ip6_handler)) {
1130                 printk(KERN_ERR "ip6ip6 init: can't register tunnel\n");
1131                 return -EAGAIN;
1132         }
1133         ip6ip6_fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1134                                          ip6ip6_tnl_dev_setup);
1135
1136         if (!ip6ip6_fb_tnl_dev) {
1137                 err = -ENOMEM;
1138                 goto fail;
1139         }
1140         ip6ip6_fb_tnl_dev->init = ip6ip6_fb_tnl_dev_init;
1141
1142         if ((err = register_netdev(ip6ip6_fb_tnl_dev))) {
1143                 free_netdev(ip6ip6_fb_tnl_dev);
1144                 goto fail;
1145         }
1146         return 0;
1147 fail:
1148         xfrm6_tunnel_deregister(&ip6ip6_handler);
1149         return err;
1150 }
1151
1152 /**
1153  * ip6_tunnel_cleanup - free resources and unregister protocol
1154  **/
1155
1156 static void __exit ip6_tunnel_cleanup(void)
1157 {
1158         if (xfrm6_tunnel_deregister(&ip6ip6_handler))
1159                 printk(KERN_INFO "ip6ip6 close: can't deregister tunnel\n");
1160
1161         unregister_netdev(ip6ip6_fb_tnl_dev);
1162 }
1163
1164 module_init(ip6_tunnel_init);
1165 module_exit(ip6_tunnel_cleanup);