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) ((__force u32)((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  *   created tunnel or NULL
 219  **/
 220
 221 static struct ip6_tnl *ip6_tnl_create(struct ip6_tnl_parm *p)
 222 {
 223         struct net_device *dev;
 224         struct ip6_tnl *t;
 225         char name[IFNAMSIZ];
 226         int err;
 227
 228         if (p->name[0]) {
 229                 strlcpy(name, p->name, IFNAMSIZ);
 230         } else {
 231                 int i;
 232                 for (i = 1; i < IP6_TNL_MAX; i++) {
 233                         sprintf(name, "ip6tnl%d", i);
 234                         if (__dev_get_by_name(name) == NULL)
 235                                 break;
 236                 }
 237                 if (i == IP6_TNL_MAX)
 238                         goto failed;
 239         }
 240         dev = alloc_netdev(sizeof (*t), name, ip6ip6_tnl_dev_setup);
 241         if (dev == NULL)
 242                 goto failed;
 243
 244         t = netdev_priv(dev);
 245         dev->init = ip6ip6_tnl_dev_init;
 246         t->parms = *p;
 247
 248         if ((err = register_netdevice(dev)) < 0) {
 249                 free_netdev(dev);
 250                 goto failed;
 251         }
 252         dev_hold(dev);
 253         ip6ip6_tnl_link(t);
 254         return t;
 255 failed:
 256         return NULL;
 257 }
 258
 259 /**
 260  * ip6ip6_tnl_locate - find or create tunnel matching given parameters
 261  *   @p: tunnel parameters
 262  *   @create: != 0 if allowed to create new tunnel if no match found
 263  *
 264  * Description:
 265  *   ip6ip6_tnl_locate() first tries to locate an existing tunnel
 266  *   based on @parms. If this is unsuccessful, but @create is set a new
 267  *   tunnel device is created and registered for use.
 268  *
 269  * Return:
 270  *   matching tunnel or NULL
 271  **/
 272
 273 static struct ip6_tnl *ip6ip6_tnl_locate(struct ip6_tnl_parm *p, int create)
 274 {
 275         struct in6_addr *remote = &p->raddr;
 276         struct in6_addr *local = &p->laddr;
 277         struct ip6_tnl *t;
 278
 279         for (t = *ip6ip6_bucket(p); t; t = t->next) {
 280                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
 281                     ipv6_addr_equal(remote, &t->parms.raddr))
 282                         return t;
 283         }
 284         if (!create)
 285                 return NULL;
 286         return ip6_tnl_create(p);
 287 }
 288
 289 /**
 290  * ip6ip6_tnl_dev_uninit - tunnel device uninitializer
 291  *   @dev: the device to be destroyed
 292  *
 293  * Description:
 294  *   ip6ip6_tnl_dev_uninit() removes tunnel from its list
 295  **/
 296
 297 static void
 298 ip6ip6_tnl_dev_uninit(struct net_device *dev)
 299 {
 300         struct ip6_tnl *t = netdev_priv(dev);
 301
 302         if (dev == ip6ip6_fb_tnl_dev) {
 303                 write_lock_bh(&ip6ip6_lock);
 304                 tnls_wc[0] = NULL;
 305                 write_unlock_bh(&ip6ip6_lock);
 306         } else {
 307                 ip6ip6_tnl_unlink(t);
 308         }
 309         ip6_tnl_dst_reset(t);
 310         dev_put(dev);
 311 }
 312
 313 /**
 314  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
 315  *   @skb: received socket buffer
 316  *
 317  * Return:
 318  *   0 if none was found,
 319  *   else index to encapsulation limit
 320  **/
 321
 322 static __u16
 323 parse_tlv_tnl_enc_lim(struct sk_buff *skb, __u8 * raw)
 324 {
 325         struct ipv6hdr *ipv6h = (struct ipv6hdr *) raw;
 326         __u8 nexthdr = ipv6h->nexthdr;
 327         __u16 off = sizeof (*ipv6h);
 328
 329         while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
 330                 __u16 optlen = 0;
 331                 struct ipv6_opt_hdr *hdr;
 332                 if (raw + off + sizeof (*hdr) > skb->data &&
 333                     !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
 334                         break;
 335
 336                 hdr = (struct ipv6_opt_hdr *) (raw + off);
 337                 if (nexthdr == NEXTHDR_FRAGMENT) {
 338                         struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
 339                         if (frag_hdr->frag_off)
 340                                 break;
 341                         optlen = 8;
 342                 } else if (nexthdr == NEXTHDR_AUTH) {
 343                         optlen = (hdr->hdrlen + 2) << 2;
 344                 } else {
 345                         optlen = ipv6_optlen(hdr);
 346                 }
 347                 if (nexthdr == NEXTHDR_DEST) {
 348                         __u16 i = off + 2;
 349                         while (1) {
 350                                 struct ipv6_tlv_tnl_enc_lim *tel;
 351
 352                                 /* No more room for encapsulation limit */
 353                                 if (i + sizeof (*tel) > off + optlen)
 354                                         break;
 355
 356                                 tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
 357                                 /* return index of option if found and valid */
 358                                 if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
 359                                     tel->length == 1)
 360                                         return i;
 361                                 /* else jump to next option */
 362                                 if (tel->type)
 363                                         i += tel->length + 2;
 364                                 else
 365                                         i++;
 366                         }
 367                 }
 368                 nexthdr = hdr->nexthdr;
 369                 off += optlen;
 370         }
 371         return 0;
 372 }
 373
 374 /**
 375  * ip6ip6_err - tunnel error handler
 376  *
 377  * Description:
 378  *   ip6ip6_err() should handle errors in the tunnel according
 379  *   to the specifications in RFC 2473.
 380  **/
 381
 382 static int
 383 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 384            int type, int code, int offset, __be32 info)
 385 {
 386         struct ipv6hdr *ipv6h = (struct ipv6hdr *) skb->data;
 387         struct ip6_tnl *t;
 388         int rel_msg = 0;
 389         int rel_type = ICMPV6_DEST_UNREACH;
 390         int rel_code = ICMPV6_ADDR_UNREACH;
 391         __u32 rel_info = 0;
 392         __u16 len;
 393         int err = -ENOENT;
 394
 395         /* If the packet doesn't contain the original IPv6 header we are
 396            in trouble since we might need the source address for further
 397            processing of the error. */
 398
 399         read_lock(&ip6ip6_lock);
 400         if ((t = ip6ip6_tnl_lookup(&ipv6h->daddr, &ipv6h->saddr)) == NULL)
 401                 goto out;
 402
 403         err = 0;
 404
 405         switch (type) {
 406                 __u32 teli;
 407                 struct ipv6_tlv_tnl_enc_lim *tel;
 408                 __u32 mtu;
 409         case ICMPV6_DEST_UNREACH:
 410                 if (net_ratelimit())
 411                         printk(KERN_WARNING
 412                                "%s: Path to destination invalid "
 413                                "or inactive!\n", t->parms.name);
 414                 rel_msg = 1;
 415                 break;
 416         case ICMPV6_TIME_EXCEED:
 417                 if (code == ICMPV6_EXC_HOPLIMIT) {
 418                         if (net_ratelimit())
 419                                 printk(KERN_WARNING
 420                                        "%s: Too small hop limit or "
 421                                        "routing loop in tunnel!\n",
 422                                        t->parms.name);
 423                         rel_msg = 1;
 424                 }
 425                 break;
 426         case ICMPV6_PARAMPROB:
 427                 teli = 0;
 428                 if (code == ICMPV6_HDR_FIELD)
 429                         teli = parse_tlv_tnl_enc_lim(skb, skb->data);
 430
 431                 if (teli && teli == ntohl(info) - 2) {
 432                         tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
 433                         if (tel->encap_limit == 0) {
 434                                 if (net_ratelimit())
 435                                         printk(KERN_WARNING
 436                                                "%s: Too small encapsulation "
 437                                                "limit or routing loop in "
 438                                                "tunnel!\n", t->parms.name);
 439                                 rel_msg = 1;
 440                         }
 441                 } else if (net_ratelimit()) {
 442                         printk(KERN_WARNING
 443                                "%s: Recipient unable to parse tunneled "
 444                                "packet!\n ", t->parms.name);
 445                 }
 446                 break;
 447         case ICMPV6_PKT_TOOBIG:
 448                 mtu = ntohl(info) - offset;
 449                 if (mtu < IPV6_MIN_MTU)
 450                         mtu = IPV6_MIN_MTU;
 451                 t->dev->mtu = mtu;
 452
 453                 if ((len = sizeof (*ipv6h) + ntohs(ipv6h->payload_len)) > mtu) {
 454                         rel_type = ICMPV6_PKT_TOOBIG;
 455                         rel_code = 0;
 456                         rel_info = mtu;
 457                         rel_msg = 1;
 458                 }
 459                 break;
 460         }
 461         if (rel_msg &&  pskb_may_pull(skb, offset + sizeof (*ipv6h))) {
 462                 struct rt6_info *rt;
 463                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
 464
 465                 if (!skb2)
 466                         goto out;
 467
 468                 dst_release(skb2->dst);
 469                 skb2->dst = NULL;
 470                 skb_pull(skb2, offset);
 471                 skb2->nh.raw = skb2->data;
 472
 473                 /* Try to guess incoming interface */
 474                 rt = rt6_lookup(&skb2->nh.ipv6h->saddr, NULL, 0, 0);
 475
 476                 if (rt && rt->rt6i_dev)
 477                         skb2->dev = rt->rt6i_dev;
 478
 479                 icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
 480
 481                 if (rt)
 482                         dst_release(&rt->u.dst);
 483
 484                 kfree_skb(skb2);
 485         }
 486 out:
 487         read_unlock(&ip6ip6_lock);
 488         return err;
 489 }
 490
 491 static inline void ip6ip6_ecn_decapsulate(struct ipv6hdr *outer_iph,
 492                                           struct sk_buff *skb)
 493 {
 494         struct ipv6hdr *inner_iph = skb->nh.ipv6h;
 495
 496         if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
 497                 IP6_ECN_set_ce(inner_iph);
 498 }
 499 static inline int ip6_tnl_rcv_ctl(struct ip6_tnl *t)
 500 {
 501         struct ip6_tnl_parm *p = &t->parms;
 502         int ret = 0;
 503
 504         if (p->flags & IP6_TNL_F_CAP_RCV) {
 505                 struct net_device *ldev = NULL;
 506
 507                 if (p->link)
 508                         ldev = dev_get_by_index(p->link);
 509
 510                 if ((ipv6_addr_is_multicast(&p->laddr) ||
 511                      likely(ipv6_chk_addr(&p->laddr, ldev, 0))) &&
 512                     likely(!ipv6_chk_addr(&p->raddr, NULL, 0)))
 513                         ret = 1;
 514
 515                 if (ldev)
 516                         dev_put(ldev);
 517         }
 518         return ret;
 519 }
 520
 521 /**
 522  * ip6ip6_rcv - decapsulate IPv6 packet and retransmit it locally
 523  *   @skb: received socket buffer
 524  *
 525  * Return: 0
 526  **/
 527
 528 static int
 529 ip6ip6_rcv(struct sk_buff *skb)
 530 {
 531         struct ipv6hdr *ipv6h;
 532         struct ip6_tnl *t;
 533
 534         ipv6h = skb->nh.ipv6h;
 535
 536         read_lock(&ip6ip6_lock);
 537
 538         if ((t = ip6ip6_tnl_lookup(&ipv6h->saddr, &ipv6h->daddr)) != NULL) {
 539                 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 540                         read_unlock(&ip6ip6_lock);
 541                         goto discard;
 542                 }
 543
 544                 if (!ip6_tnl_rcv_ctl(t)) {
 545                         t->stat.rx_dropped++;
 546                         read_unlock(&ip6ip6_lock);
 547                         goto discard;
 548                 }
 549                 secpath_reset(skb);
 550                 skb->mac.raw = skb->nh.raw;
 551                 skb->nh.raw = skb->data;
 552                 skb->protocol = htons(ETH_P_IPV6);
 553                 skb->pkt_type = PACKET_HOST;
 554                 memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
 555                 skb->dev = t->dev;
 556                 dst_release(skb->dst);
 557                 skb->dst = NULL;
 558                 nf_reset(skb);
 559                 if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
 560                         ipv6_copy_dscp(ipv6h, skb->nh.ipv6h);
 561                 ip6ip6_ecn_decapsulate(ipv6h, skb);
 562                 t->stat.rx_packets++;
 563                 t->stat.rx_bytes += skb->len;
 564                 netif_rx(skb);
 565                 read_unlock(&ip6ip6_lock);
 566                 return 0;
 567         }
 568         read_unlock(&ip6ip6_lock);
 569         return 1;
 570
 571 discard:
 572         kfree_skb(skb);
 573         return 0;
 574 }
 575
 576 struct ipv6_tel_txoption {
 577         struct ipv6_txoptions ops;
 578         __u8 dst_opt[8];
 579 };
 580
 581 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
 582 {
 583         memset(opt, 0, sizeof(struct ipv6_tel_txoption));
 584
 585         opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
 586         opt->dst_opt[3] = 1;
 587         opt->dst_opt[4] = encap_limit;
 588         opt->dst_opt[5] = IPV6_TLV_PADN;
 589         opt->dst_opt[6] = 1;
 590
 591         opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
 592         opt->ops.opt_nflen = 8;
 593 }
 594
 595 /**
 596  * ip6ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
 597  *   @t: the outgoing tunnel device
 598  *   @hdr: IPv6 header from the incoming packet
 599  *
 600  * Description:
 601  *   Avoid trivial tunneling loop by checking that tunnel exit-point
 602  *   doesn't match source of incoming packet.
 603  *
 604  * Return:
 605  *   1 if conflict,
 606  *   0 else
 607  **/
 608
 609 static inline int
 610 ip6ip6_tnl_addr_conflict(struct ip6_tnl *t, struct ipv6hdr *hdr)
 611 {
 612         return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
 613 }
 614
 615 static inline int ip6_tnl_xmit_ctl(struct ip6_tnl *t)
 616 {
 617         struct ip6_tnl_parm *p = &t->parms;
 618         int ret = 0;
 619
 620         if (p->flags & IP6_TNL_F_CAP_XMIT) {
 621                 struct net_device *ldev = NULL;
 622
 623                 if (p->link)
 624                         ldev = dev_get_by_index(p->link);
 625
 626                 if (unlikely(!ipv6_chk_addr(&p->laddr, ldev, 0)))
 627                         printk(KERN_WARNING
 628                                "%s xmit: Local address not yet configured!\n",
 629                                p->name);
 630                 else if (!ipv6_addr_is_multicast(&p->raddr) &&
 631                          unlikely(ipv6_chk_addr(&p->raddr, NULL, 0)))
 632                         printk(KERN_WARNING
 633                                "%s xmit: Routing loop! "
 634                                "Remote address found on this node!\n",
 635                                p->name);
 636                 else
 637                         ret = 1;
 638                 if (ldev)
 639                         dev_put(ldev);
 640         }
 641         return ret;
 642 }
 643 /**
 644  * ip6ip6_tnl_xmit - encapsulate packet and send
 645  *   @skb: the outgoing socket buffer
 646  *   @dev: the outgoing tunnel device
 647  *
 648  * Description:
 649  *   Build new header and do some sanity checks on the packet before sending
 650  *   it.
 651  *
 652  * Return:
 653  *   0
 654  **/
 655
 656 static int
 657 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
 658 {
 659         struct ip6_tnl *t = netdev_priv(dev);
 660         struct net_device_stats *stats = &t->stat;
 661         struct ipv6hdr *ipv6h = skb->nh.ipv6h;
 662         int encap_limit = -1;
 663         struct ipv6_tel_txoption opt;
 664         __u16 offset;
 665         struct flowi fl;
 666         struct dst_entry *dst;
 667         struct net_device *tdev;
 668         int mtu;
 669         int max_headroom = sizeof(struct ipv6hdr);
 670         u8 proto;
 671         int err;
 672         int pkt_len;
 673         int dsfield;
 674
 675         if (t->recursion++) {
 676                 stats->collisions++;
 677                 goto tx_err;
 678         }
 679         if (skb->protocol != htons(ETH_P_IPV6) ||
 680             !ip6_tnl_xmit_ctl(t) || ip6ip6_tnl_addr_conflict(t, ipv6h))
 681                 goto tx_err;
 682
 683         if ((offset = parse_tlv_tnl_enc_lim(skb, skb->nh.raw)) > 0) {
 684                 struct ipv6_tlv_tnl_enc_lim *tel;
 685                 tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->nh.raw[offset];
 686                 if (tel->encap_limit == 0) {
 687                         icmpv6_send(skb, ICMPV6_PARAMPROB,
 688                                     ICMPV6_HDR_FIELD, offset + 2, skb->dev);
 689                         goto tx_err;
 690                 }
 691                 encap_limit = tel->encap_limit - 1;
 692         } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
 693                 encap_limit = t->parms.encap_limit;
 694
 695         memcpy(&fl, &t->fl, sizeof (fl));
 696         proto = fl.proto;
 697
 698         dsfield = ipv6_get_dsfield(ipv6h);
 699         if ((t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS))
 700                 fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
 701         if ((t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL))
 702                 fl.fl6_flowlabel |= (*(__be32 *) ipv6h & IPV6_FLOWLABEL_MASK);
 703
 704         if ((dst = ip6_tnl_dst_check(t)) != NULL)
 705                 dst_hold(dst);
 706         else {
 707                 dst = ip6_route_output(NULL, &fl);
 708
 709                 if (dst->error || xfrm_lookup(&dst, &fl, NULL, 0) < 0)
 710                         goto tx_err_link_failure;
 711         }
 712
 713         tdev = dst->dev;
 714
 715         if (tdev == dev) {
 716                 stats->collisions++;
 717                 if (net_ratelimit())
 718                         printk(KERN_WARNING
 719                                "%s: Local routing loop detected!\n",
 720                                t->parms.name);
 721                 goto tx_err_dst_release;
 722         }
 723         mtu = dst_mtu(dst) - sizeof (*ipv6h);
 724         if (encap_limit >= 0) {
 725                 max_headroom += 8;
 726                 mtu -= 8;
 727         }
 728         if (mtu < IPV6_MIN_MTU)
 729                 mtu = IPV6_MIN_MTU;
 730         if (skb->dst && mtu < dst_mtu(skb->dst)) {
 731                 struct rt6_info *rt = (struct rt6_info *) skb->dst;
 732                 rt->rt6i_flags |= RTF_MODIFIED;
 733                 rt->u.dst.metrics[RTAX_MTU-1] = mtu;
 734         }
 735         if (skb->len > mtu) {
 736                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 737                 goto tx_err_dst_release;
 738         }
 739
 740         /*
 741          * Okay, now see if we can stuff it in the buffer as-is.
 742          */
 743         max_headroom += LL_RESERVED_SPACE(tdev);
 744
 745         if (skb_headroom(skb) < max_headroom ||
 746             skb_cloned(skb) || skb_shared(skb)) {
 747                 struct sk_buff *new_skb;
 748
 749                 if (!(new_skb = skb_realloc_headroom(skb, max_headroom)))
 750                         goto tx_err_dst_release;
 751
 752                 if (skb->sk)
 753                         skb_set_owner_w(new_skb, skb->sk);
 754                 kfree_skb(skb);
 755                 skb = new_skb;
 756         }
 757         dst_release(skb->dst);
 758         skb->dst = dst_clone(dst);
 759
 760         skb->h.raw = skb->nh.raw;
 761
 762         if (encap_limit >= 0) {
 763                 init_tel_txopt(&opt, encap_limit);
 764                 ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
 765         }
 766         skb->nh.raw = skb_push(skb, sizeof(struct ipv6hdr));
 767         ipv6h = skb->nh.ipv6h;
 768         *(__be32*)ipv6h = fl.fl6_flowlabel | htonl(0x60000000);
 769         dsfield = INET_ECN_encapsulate(0, dsfield);
 770         ipv6_change_dsfield(ipv6h, ~INET_ECN_MASK, dsfield);
 771         ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 772         ipv6h->hop_limit = t->parms.hop_limit;
 773         ipv6h->nexthdr = proto;
 774         ipv6_addr_copy(&ipv6h->saddr, &fl.fl6_src);
 775         ipv6_addr_copy(&ipv6h->daddr, &fl.fl6_dst);
 776         nf_reset(skb);
 777         pkt_len = skb->len;
 778         err = NF_HOOK(PF_INET6, NF_IP6_LOCAL_OUT, skb, NULL,
 779                       skb->dst->dev, dst_output);
 780
 781         if (net_xmit_eval(err) == 0) {
 782                 stats->tx_bytes += pkt_len;
 783                 stats->tx_packets++;
 784         } else {
 785                 stats->tx_errors++;
 786                 stats->tx_aborted_errors++;
 787         }
 788         ip6_tnl_dst_store(t, dst);
 789         t->recursion--;
 790         return 0;
 791 tx_err_link_failure:
 792         stats->tx_carrier_errors++;
 793         dst_link_failure(skb);
 794 tx_err_dst_release:
 795         dst_release(dst);
 796 tx_err:
 797         stats->tx_errors++;
 798         stats->tx_dropped++;
 799         kfree_skb(skb);
 800         t->recursion--;
 801         return 0;
 802 }
 803
 804 static void ip6_tnl_set_cap(struct ip6_tnl *t)
 805 {
 806         struct ip6_tnl_parm *p = &t->parms;
 807         int ltype = ipv6_addr_type(&p->laddr);
 808         int rtype = ipv6_addr_type(&p->raddr);
 809
 810         p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV);
 811
 812         if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
 813             rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
 814             !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
 815             (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
 816                 if (ltype&IPV6_ADDR_UNICAST)
 817                         p->flags |= IP6_TNL_F_CAP_XMIT;
 818                 if (rtype&IPV6_ADDR_UNICAST)
 819                         p->flags |= IP6_TNL_F_CAP_RCV;
 820         }
 821 }
 822
 823 static void ip6ip6_tnl_link_config(struct ip6_tnl *t)
 824 {
 825         struct net_device *dev = t->dev;
 826         struct ip6_tnl_parm *p = &t->parms;
 827         struct flowi *fl = &t->fl;
 828
 829         memcpy(&dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
 830         memcpy(&dev->broadcast, &p->raddr, sizeof(struct in6_addr));
 831
 832         /* Set up flowi template */
 833         ipv6_addr_copy(&fl->fl6_src, &p->laddr);
 834         ipv6_addr_copy(&fl->fl6_dst, &p->raddr);
 835         fl->oif = p->link;
 836         fl->fl6_flowlabel = 0;
 837
 838         if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
 839                 fl->fl6_flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
 840         if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
 841                 fl->fl6_flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
 842
 843         ip6_tnl_set_cap(t);
 844
 845         if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
 846                 dev->flags |= IFF_POINTOPOINT;
 847         else
 848                 dev->flags &= ~IFF_POINTOPOINT;
 849
 850         dev->iflink = p->link;
 851
 852         if (p->flags & IP6_TNL_F_CAP_XMIT) {
 853                 int strict = (ipv6_addr_type(&p->raddr) &
 854                               (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
 855
 856                 struct rt6_info *rt = rt6_lookup(&p->raddr, &p->laddr,
 857                                                  p->link, strict);
 858
 859                 if (rt == NULL)
 860                         return;
 861
 862                 if (rt->rt6i_dev) {
 863                         dev->hard_header_len = rt->rt6i_dev->hard_header_len +
 864                                 sizeof (struct ipv6hdr);
 865
 866                         dev->mtu = rt->rt6i_dev->mtu - sizeof (struct ipv6hdr);
 867
 868                         if (dev->mtu < IPV6_MIN_MTU)
 869                                 dev->mtu = IPV6_MIN_MTU;
 870                 }
 871                 dst_release(&rt->u.dst);
 872         }
 873 }
 874
 875 /**
 876  * ip6ip6_tnl_change - update the tunnel parameters
 877  *   @t: tunnel to be changed
 878  *   @p: tunnel configuration parameters
 879  *   @active: != 0 if tunnel is ready for use
 880  *
 881  * Description:
 882  *   ip6ip6_tnl_change() updates the tunnel parameters
 883  **/
 884
 885 static int
 886 ip6ip6_tnl_change(struct ip6_tnl *t, struct ip6_tnl_parm *p)
 887 {
 888         ipv6_addr_copy(&t->parms.laddr, &p->laddr);
 889         ipv6_addr_copy(&t->parms.raddr, &p->raddr);
 890         t->parms.flags = p->flags;
 891         t->parms.hop_limit = p->hop_limit;
 892         t->parms.encap_limit = p->encap_limit;
 893         t->parms.flowinfo = p->flowinfo;
 894         t->parms.link = p->link;
 895         ip6_tnl_dst_reset(t);
 896         ip6ip6_tnl_link_config(t);
 897         return 0;
 898 }
 899
 900 /**
 901  * ip6ip6_tnl_ioctl - configure ipv6 tunnels from userspace
 902  *   @dev: virtual device associated with tunnel
 903  *   @ifr: parameters passed from userspace
 904  *   @cmd: command to be performed
 905  *
 906  * Description:
 907  *   ip6ip6_tnl_ioctl() is used for managing IPv6 tunnels
 908  *   from userspace.
 909  *
 910  *   The possible commands are the following:
 911  *     %SIOCGETTUNNEL: get tunnel parameters for device
 912  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
 913  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
 914  *     %SIOCDELTUNNEL: delete tunnel
 915  *
 916  *   The fallback device "ip6tnl0", created during module
 917  *   initialization, can be used for creating other tunnel devices.
 918  *
 919  * Return:
 920  *   0 on success,
 921  *   %-EFAULT if unable to copy data to or from userspace,
 922  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
 923  *   %-EINVAL if passed tunnel parameters are invalid,
 924  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
 925  *   %-ENODEV if attempting to change or delete a nonexisting device
 926  **/
 927
 928 static int
 929 ip6ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 930 {
 931         int err = 0;
 932         struct ip6_tnl_parm p;
 933         struct ip6_tnl *t = NULL;
 934
 935         switch (cmd) {
 936         case SIOCGETTUNNEL:
 937                 if (dev == ip6ip6_fb_tnl_dev) {
 938                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p))) {
 939                                 err = -EFAULT;
 940                                 break;
 941                         }
 942                         t = ip6ip6_tnl_locate(&p, 0);
 943                 }
 944                 if (t == NULL)
 945                         t = netdev_priv(dev);
 946                 memcpy(&p, &t->parms, sizeof (p));
 947                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof (p))) {
 948                         err = -EFAULT;
 949                 }
 950                 break;
 951         case SIOCADDTUNNEL:
 952         case SIOCCHGTUNNEL:
 953                 err = -EPERM;
 954                 if (!capable(CAP_NET_ADMIN))
 955                         break;
 956                 err = -EFAULT;
 957                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
 958                         break;
 959                 err = -EINVAL;
 960                 if (p.proto != IPPROTO_IPV6)
 961                         break;
 962                 t = ip6ip6_tnl_locate(&p, cmd == SIOCADDTUNNEL);
 963                 if (dev != ip6ip6_fb_tnl_dev && cmd == SIOCCHGTUNNEL) {
 964                         if (t != NULL) {
 965                                 if (t->dev != dev) {
 966                                         err = -EEXIST;
 967                                         break;
 968                                 }
 969                         } else
 970                                 t = netdev_priv(dev);
 971
 972                         ip6ip6_tnl_unlink(t);
 973                         err = ip6ip6_tnl_change(t, &p);
 974                         ip6ip6_tnl_link(t);
 975                         netdev_state_change(dev);
 976                 }
 977                 if (t) {
 978                         err = 0;
 979                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof (p)))
 980                                 err = -EFAULT;
 981
 982                 } else
 983                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 984                 break;
 985         case SIOCDELTUNNEL:
 986                 err = -EPERM;
 987                 if (!capable(CAP_NET_ADMIN))
 988                         break;
 989
 990                 if (dev == ip6ip6_fb_tnl_dev) {
 991                         err = -EFAULT;
 992                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof (p)))
 993                                 break;
 994                         err = -ENOENT;
 995                         if ((t = ip6ip6_tnl_locate(&p, 0)) == NULL)
 996                                 break;
 997                         err = -EPERM;
 998                         if (t->dev == ip6ip6_fb_tnl_dev)
 999                                 break;
1000                         dev = t->dev;
1001                 }
1002                 err = 0;
1003                 unregister_netdevice(dev);
1004                 break;
1005         default:
1006                 err = -EINVAL;
1007         }
1008         return err;
1009 }
1010
1011 /**
1012  * ip6ip6_tnl_get_stats - return the stats for tunnel device
1013  *   @dev: virtual device associated with tunnel
1014  *
1015  * Return: stats for device
1016  **/
1017
1018 static struct net_device_stats *
1019 ip6ip6_tnl_get_stats(struct net_device *dev)
1020 {
1021         return &(((struct ip6_tnl *)netdev_priv(dev))->stat);
1022 }
1023
1024 /**
1025  * ip6ip6_tnl_change_mtu - change mtu manually for tunnel device
1026  *   @dev: virtual device associated with tunnel
1027  *   @new_mtu: the new mtu
1028  *
1029  * Return:
1030  *   0 on success,
1031  *   %-EINVAL if mtu too small
1032  **/
1033
1034 static int
1035 ip6ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1036 {
1037         if (new_mtu < IPV6_MIN_MTU) {
1038                 return -EINVAL;
1039         }
1040         dev->mtu = new_mtu;
1041         return 0;
1042 }
1043
1044 /**
1045  * ip6ip6_tnl_dev_setup - setup virtual tunnel device
1046  *   @dev: virtual device associated with tunnel
1047  *
1048  * Description:
1049  *   Initialize function pointers and device parameters
1050  **/
1051
1052 static void ip6ip6_tnl_dev_setup(struct net_device *dev)
1053 {
1054         SET_MODULE_OWNER(dev);
1055         dev->uninit = ip6ip6_tnl_dev_uninit;
1056         dev->destructor = free_netdev;
1057         dev->hard_start_xmit = ip6ip6_tnl_xmit;
1058         dev->get_stats = ip6ip6_tnl_get_stats;
1059         dev->do_ioctl = ip6ip6_tnl_ioctl;
1060         dev->change_mtu = ip6ip6_tnl_change_mtu;
1061
1062         dev->type = ARPHRD_TUNNEL6;
1063         dev->hard_header_len = LL_MAX_HEADER + sizeof (struct ipv6hdr);
1064         dev->mtu = ETH_DATA_LEN - sizeof (struct ipv6hdr);
1065         dev->flags |= IFF_NOARP;
1066         dev->addr_len = sizeof(struct in6_addr);
1067 }
1068
1069
1070 /**
1071  * ip6ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1072  *   @dev: virtual device associated with tunnel
1073  **/
1074
1075 static inline void
1076 ip6ip6_tnl_dev_init_gen(struct net_device *dev)
1077 {
1078         struct ip6_tnl *t = netdev_priv(dev);
1079         t->fl.proto = IPPROTO_IPV6;
1080         t->dev = dev;
1081         strcpy(t->parms.name, dev->name);
1082 }
1083
1084 /**
1085  * ip6ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1086  *   @dev: virtual device associated with tunnel
1087  **/
1088
1089 static int
1090 ip6ip6_tnl_dev_init(struct net_device *dev)
1091 {
1092         struct ip6_tnl *t = netdev_priv(dev);
1093         ip6ip6_tnl_dev_init_gen(dev);
1094         ip6ip6_tnl_link_config(t);
1095         return 0;
1096 }
1097
1098 /**
1099  * ip6ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1100  *   @dev: fallback device
1101  *
1102  * Return: 0
1103  **/
1104
1105 static int
1106 ip6ip6_fb_tnl_dev_init(struct net_device *dev)
1107 {
1108         struct ip6_tnl *t = netdev_priv(dev);
1109         ip6ip6_tnl_dev_init_gen(dev);
1110         dev_hold(dev);
1111         tnls_wc[0] = t;
1112         return 0;
1113 }
1114
1115 static struct xfrm6_tunnel ip6ip6_handler = {
1116         .handler        = ip6ip6_rcv,
1117         .err_handler    = ip6ip6_err,
1118         .priority       =       1,
1119 };
1120
1121 /**
1122  * ip6_tunnel_init - register protocol and reserve needed resources
1123  *
1124  * Return: 0 on success
1125  **/
1126
1127 static int __init ip6_tunnel_init(void)
1128 {
1129         int  err;
1130
1131         if (xfrm6_tunnel_register(&ip6ip6_handler)) {
1132                 printk(KERN_ERR "ip6ip6 init: can't register tunnel\n");
1133                 return -EAGAIN;
1134         }
1135         ip6ip6_fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1136                                          ip6ip6_tnl_dev_setup);
1137
1138         if (!ip6ip6_fb_tnl_dev) {
1139                 err = -ENOMEM;
1140                 goto fail;
1141         }
1142         ip6ip6_fb_tnl_dev->init = ip6ip6_fb_tnl_dev_init;
1143
1144         if ((err = register_netdev(ip6ip6_fb_tnl_dev))) {
1145                 free_netdev(ip6ip6_fb_tnl_dev);
1146                 goto fail;
1147         }
1148         return 0;
1149 fail:
1150         xfrm6_tunnel_deregister(&ip6ip6_handler);
1151         return err;
1152 }
1153
1154 static void __exit ip6ip6_destroy_tunnels(void)
1155 {
1156         int h;
1157         struct ip6_tnl *t;
1158
1159         for (h = 0; h < HASH_SIZE; h++) {
1160                 while ((t = tnls_r_l[h]) != NULL)
1161                         unregister_netdevice(t->dev);
1162         }
1163
1164         t = tnls_wc[0];
1165         unregister_netdevice(t->dev);
1166 }
1167
1168 /**
1169  * ip6_tunnel_cleanup - free resources and unregister protocol
1170  **/
1171
1172 static void __exit ip6_tunnel_cleanup(void)
1173 {
1174         if (xfrm6_tunnel_deregister(&ip6ip6_handler))
1175                 printk(KERN_INFO "ip6ip6 close: can't deregister tunnel\n");
1176
1177         rtnl_lock();
1178         ip6ip6_destroy_tunnels();
1179         rtnl_unlock();
1180 }
1181
1182 module_init(ip6_tunnel_init);
1183 module_exit(ip6_tunnel_cleanup);