net/ipv6/exthdrs.c

   1 /*
   2  *      Extension Header handling for IPv6
   3  *      Linux INET6 implementation
   4  *
   5  *      Authors:
   6  *      Pedro Roque             <roque@di.fc.ul.pt>
   7  *      Andi Kleen              <ak@muc.de>
   8  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   9  *
  10  *      This program is free software; you can redistribute it and/or
  11  *      modify it under the terms of the GNU General Public License
  12  *      as published by the Free Software Foundation; either version
  13  *      2 of the License, or (at your option) any later version.
  14  */
  15
  16 /* Changes:
  17  *      yoshfuji                : ensure not to overrun while parsing
  18  *                                tlv options.
  19  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
  20  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
  21  *                                handlers as inet6_protocol{}.
  22  */
  23
  24 #include <linux/errno.h>
  25 #include <linux/types.h>
  26 #include <linux/socket.h>
  27 #include <linux/sockios.h>
  28 #include <linux/net.h>
  29 #include <linux/netdevice.h>
  30 #include <linux/in6.h>
  31 #include <linux/icmpv6.h>
  32 #include <linux/slab.h>
  33
  34 #include <net/dst.h>
  35 #include <net/sock.h>
  36 #include <net/snmp.h>
  37
  38 #include <net/ipv6.h>
  39 #include <net/protocol.h>
  40 #include <net/transp_v6.h>
  41 #include <net/rawv6.h>
  42 #include <net/ndisc.h>
  43 #include <net/ip6_route.h>
  44 #include <net/addrconf.h>
  45 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  46 #include <net/xfrm.h>
  47 #endif
  48
  49 #include <asm/uaccess.h>
  50
  51 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
  52 {
  53         const unsigned char *nh = skb_network_header(skb);
  54         int packet_len = skb->tail - skb->network_header;
  55         struct ipv6_opt_hdr *hdr;
  56         int len;
  57
  58         if (offset + 2 > packet_len)
  59                 goto bad;
  60         hdr = (struct ipv6_opt_hdr *)(nh + offset);
  61         len = ((hdr->hdrlen + 1) << 3);
  62
  63         if (offset + len > packet_len)
  64                 goto bad;
  65
  66         offset += 2;
  67         len -= 2;
  68
  69         while (len > 0) {
  70                 int opttype = nh[offset];
  71                 int optlen;
  72
  73                 if (opttype == type)
  74                         return offset;
  75
  76                 switch (opttype) {
  77                 case IPV6_TLV_PAD0:
  78                         optlen = 1;
  79                         break;
  80                 default:
  81                         optlen = nh[offset + 1] + 2;
  82                         if (optlen > len)
  83                                 goto bad;
  84                         break;
  85                 }
  86                 offset += optlen;
  87                 len -= optlen;
  88         }
  89         /* not_found */
  90  bad:
  91         return -1;
  92 }
  93 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
  94
  95 /*
  96  *      Parsing tlv encoded headers.
  97  *
  98  *      Parsing function "func" returns 1, if parsing succeed
  99  *      and 0, if it failed.
 100  *      It MUST NOT touch skb->h.
 101  */
 102
 103 struct tlvtype_proc {
 104         int     type;
 105         int     (*func)(struct sk_buff *skb, int offset);
 106 };
 107
 108 /*********************
 109   Generic functions
 110  *********************/
 111
 112 /* An unknown option is detected, decide what to do */
 113
 114 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
 115 {
 116         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
 117         case 0: /* ignore */
 118                 return 1;
 119
 120         case 1: /* drop packet */
 121                 break;
 122
 123         case 3: /* Send ICMP if not a multicast address and drop packet */
 124                 /* Actually, it is redundant check. icmp_send
 125                    will recheck in any case.
 126                  */
 127                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
 128                         break;
 129         case 2: /* send ICMP PARM PROB regardless and drop packet */
 130                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
 131                 return 0;
 132         }
 133
 134         kfree_skb(skb);
 135         return 0;
 136 }
 137
 138 /* Parse tlv encoded option header (hop-by-hop or destination) */
 139
 140 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
 141 {
 142         struct tlvtype_proc *curr;
 143         const unsigned char *nh = skb_network_header(skb);
 144         int off = skb_network_header_len(skb);
 145         int len = (skb_transport_header(skb)[1] + 1) << 3;
 146
 147         if (skb_transport_offset(skb) + len > skb_headlen(skb))
 148                 goto bad;
 149
 150         off += 2;
 151         len -= 2;
 152
 153         while (len > 0) {
 154                 int optlen = nh[off + 1] + 2;
 155
 156                 switch (nh[off]) {
 157                 case IPV6_TLV_PAD0:
 158                         optlen = 1;
 159                         break;
 160
 161                 case IPV6_TLV_PADN:
 162                         break;
 163
 164                 default: /* Other TLV code so scan list */
 165                         if (optlen > len)
 166                                 goto bad;
 167                         for (curr=procs; curr->type >= 0; curr++) {
 168                                 if (curr->type == nh[off]) {
 169                                         /* type specific length/alignment
 170                                            checks will be performed in the
 171                                            func(). */
 172                                         if (curr->func(skb, off) == 0)
 173                                                 return 0;
 174                                         break;
 175                                 }
 176                         }
 177                         if (curr->type < 0) {
 178                                 if (ip6_tlvopt_unknown(skb, off) == 0)
 179                                         return 0;
 180                         }
 181                         break;
 182                 }
 183                 off += optlen;
 184                 len -= optlen;
 185         }
 186         if (len == 0)
 187                 return 1;
 188 bad:
 189         kfree_skb(skb);
 190         return 0;
 191 }
 192
 193 /*****************************
 194   Destination options header.
 195  *****************************/
 196
 197 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 198 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
 199 {
 200         struct ipv6_destopt_hao *hao;
 201         struct inet6_skb_parm *opt = IP6CB(skb);
 202         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 203         struct in6_addr tmp_addr;
 204         int ret;
 205
 206         if (opt->dsthao) {
 207                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
 208                 goto discard;
 209         }
 210         opt->dsthao = opt->dst1;
 211         opt->dst1 = 0;
 212
 213         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 214
 215         if (hao->length != 16) {
 216                 LIMIT_NETDEBUG(
 217                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
 218                 goto discard;
 219         }
 220
 221         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 222                 LIMIT_NETDEBUG(
 223                         KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
 224                 goto discard;
 225         }
 226
 227         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 228                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 229         if (unlikely(ret < 0))
 230                 goto discard;
 231
 232         if (skb_cloned(skb)) {
 233                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 234                         goto discard;
 235
 236                 /* update all variable using below by copied skbuff */
 237                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
 238                                                   optoff);
 239                 ipv6h = ipv6_hdr(skb);
 240         }
 241
 242         if (skb->ip_summed == CHECKSUM_COMPLETE)
 243                 skb->ip_summed = CHECKSUM_NONE;
 244
 245         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
 246         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
 247         ipv6_addr_copy(&hao->addr, &tmp_addr);
 248
 249         if (skb->tstamp.tv64 == 0)
 250                 __net_timestamp(skb);
 251
 252         return 1;
 253
 254  discard:
 255         kfree_skb(skb);
 256         return 0;
 257 }
 258 #endif
 259
 260 static struct tlvtype_proc tlvprocdestopt_lst[] = {
 261 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 262         {
 263                 .type   = IPV6_TLV_HAO,
 264                 .func   = ipv6_dest_hao,
 265         },
 266 #endif
 267         {-1,                    NULL}
 268 };
 269
 270 static int ipv6_destopt_rcv(struct sk_buff *skb)
 271 {
 272         struct inet6_skb_parm *opt = IP6CB(skb);
 273 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 274         __u16 dstbuf;
 275 #endif
 276         struct dst_entry *dst = skb_dst(skb);
 277
 278         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 279             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 280                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 281                 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst),
 282                                  IPSTATS_MIB_INHDRERRORS);
 283                 kfree_skb(skb);
 284                 return -1;
 285         }
 286
 287         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 288 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 289         dstbuf = opt->dst1;
 290 #endif
 291
 292         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
 293                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 294                 opt = IP6CB(skb);
 295 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 296                 opt->nhoff = dstbuf;
 297 #else
 298                 opt->nhoff = opt->dst1;
 299 #endif
 300                 return 1;
 301         }
 302
 303         IP6_INC_STATS_BH(dev_net(dst->dev),
 304                          ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 305         return -1;
 306 }
 307
 308 /********************************
 309   Routing header.
 310  ********************************/
 311
 312 /* called with rcu_read_lock() */
 313 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 314 {
 315         struct inet6_skb_parm *opt = IP6CB(skb);
 316         struct in6_addr *addr = NULL;
 317         struct in6_addr daddr;
 318         struct inet6_dev *idev;
 319         int n, i;
 320         struct ipv6_rt_hdr *hdr;
 321         struct rt0_hdr *rthdr;
 322         struct net *net = dev_net(skb->dev);
 323         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 324
 325         idev = __in6_dev_get(skb->dev);
 326         if (idev && accept_source_route > idev->cnf.accept_source_route)
 327                 accept_source_route = idev->cnf.accept_source_route;
 328
 329         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 330             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 331                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 332                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 333                                  IPSTATS_MIB_INHDRERRORS);
 334                 kfree_skb(skb);
 335                 return -1;
 336         }
 337
 338         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 339
 340         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 341             skb->pkt_type != PACKET_HOST) {
 342                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 343                                  IPSTATS_MIB_INADDRERRORS);
 344                 kfree_skb(skb);
 345                 return -1;
 346         }
 347
 348 looped_back:
 349         if (hdr->segments_left == 0) {
 350                 switch (hdr->type) {
 351 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 352                 case IPV6_SRCRT_TYPE_2:
 353                         /* Silently discard type 2 header unless it was
 354                          * processed by own
 355                          */
 356                         if (!addr) {
 357                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 358                                                  IPSTATS_MIB_INADDRERRORS);
 359                                 kfree_skb(skb);
 360                                 return -1;
 361                         }
 362                         break;
 363 #endif
 364                 default:
 365                         break;
 366                 }
 367
 368                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 369                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 370                 opt->dst0 = opt->dst1;
 371                 opt->dst1 = 0;
 372                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 373                 return 1;
 374         }
 375
 376         switch (hdr->type) {
 377 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 378         case IPV6_SRCRT_TYPE_2:
 379                 if (accept_source_route < 0)
 380                         goto unknown_rh;
 381                 /* Silently discard invalid RTH type 2 */
 382                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 383                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 384                                          IPSTATS_MIB_INHDRERRORS);
 385                         kfree_skb(skb);
 386                         return -1;
 387                 }
 388                 break;
 389 #endif
 390         default:
 391                 goto unknown_rh;
 392         }
 393
 394         /*
 395          *      This is the routing header forwarding algorithm from
 396          *      RFC 2460, page 16.
 397          */
 398
 399         n = hdr->hdrlen >> 1;
 400
 401         if (hdr->segments_left > n) {
 402                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 403                                  IPSTATS_MIB_INHDRERRORS);
 404                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 405                                   ((&hdr->segments_left) -
 406                                    skb_network_header(skb)));
 407                 return -1;
 408         }
 409
 410         /* We are about to mangle packet header. Be careful!
 411            Do not damage packets queued somewhere.
 412          */
 413         if (skb_cloned(skb)) {
 414                 /* the copy is a forwarded packet */
 415                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 416                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 417                                          IPSTATS_MIB_OUTDISCARDS);
 418                         kfree_skb(skb);
 419                         return -1;
 420                 }
 421                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 422         }
 423
 424         if (skb->ip_summed == CHECKSUM_COMPLETE)
 425                 skb->ip_summed = CHECKSUM_NONE;
 426
 427         i = n - --hdr->segments_left;
 428
 429         rthdr = (struct rt0_hdr *) hdr;
 430         addr = rthdr->addr;
 431         addr += i - 1;
 432
 433         switch (hdr->type) {
 434 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 435         case IPV6_SRCRT_TYPE_2:
 436                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 437                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 438                                      IPPROTO_ROUTING) < 0) {
 439                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 440                                          IPSTATS_MIB_INADDRERRORS);
 441                         kfree_skb(skb);
 442                         return -1;
 443                 }
 444                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 445                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 446                                          IPSTATS_MIB_INADDRERRORS);
 447                         kfree_skb(skb);
 448                         return -1;
 449                 }
 450                 break;
 451 #endif
 452         default:
 453                 break;
 454         }
 455
 456         if (ipv6_addr_is_multicast(addr)) {
 457                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 458                                  IPSTATS_MIB_INADDRERRORS);
 459                 kfree_skb(skb);
 460                 return -1;
 461         }
 462
 463         ipv6_addr_copy(&daddr, addr);
 464         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 465         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 466
 467         skb_dst_drop(skb);
 468         ip6_route_input(skb);
 469         if (skb_dst(skb)->error) {
 470                 skb_push(skb, skb->data - skb_network_header(skb));
 471                 dst_input(skb);
 472                 return -1;
 473         }
 474
 475         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 476                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 477                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 478                                          IPSTATS_MIB_INHDRERRORS);
 479                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 480                                     0);
 481                         kfree_skb(skb);
 482                         return -1;
 483                 }
 484                 ipv6_hdr(skb)->hop_limit--;
 485                 goto looped_back;
 486         }
 487
 488         skb_push(skb, skb->data - skb_network_header(skb));
 489         dst_input(skb);
 490         return -1;
 491
 492 unknown_rh:
 493         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 494         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 495                           (&hdr->type) - skb_network_header(skb));
 496         return -1;
 497 }
 498
 499 static const struct inet6_protocol rthdr_protocol = {
 500         .handler        =       ipv6_rthdr_rcv,
 501         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 502 };
 503
 504 static const struct inet6_protocol destopt_protocol = {
 505         .handler        =       ipv6_destopt_rcv,
 506         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 507 };
 508
 509 static const struct inet6_protocol nodata_protocol = {
 510         .handler        =       dst_discard,
 511         .flags          =       INET6_PROTO_NOPOLICY,
 512 };
 513
 514 int __init ipv6_exthdrs_init(void)
 515 {
 516         int ret;
 517
 518         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 519         if (ret)
 520                 goto out;
 521
 522         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 523         if (ret)
 524                 goto out_rthdr;
 525
 526         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 527         if (ret)
 528                 goto out_destopt;
 529
 530 out:
 531         return ret;
 532 out_rthdr:
 533         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 534 out_destopt:
 535         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 536         goto out;
 537 };
 538
 539 void ipv6_exthdrs_exit(void)
 540 {
 541         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 542         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 543         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 544 }
 545
 546 /**********************************
 547   Hop-by-hop options.
 548  **********************************/
 549
 550 /*
 551  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 552  */
 553 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 554 {
 555         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 556 }
 557
 558 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 559 {
 560         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 561 }
 562
 563 /* Router Alert as of RFC 2711 */
 564
 565 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 566 {
 567         const unsigned char *nh = skb_network_header(skb);
 568
 569         if (nh[optoff + 1] == 2) {
 570                 IP6CB(skb)->ra = optoff;
 571                 return 1;
 572         }
 573         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 574                        nh[optoff + 1]);
 575         kfree_skb(skb);
 576         return 0;
 577 }
 578
 579 /* Jumbo payload */
 580
 581 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 582 {
 583         const unsigned char *nh = skb_network_header(skb);
 584         struct net *net = ipv6_skb_net(skb);
 585         u32 pkt_len;
 586
 587         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 588                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 589                                nh[optoff+1]);
 590                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 591                                  IPSTATS_MIB_INHDRERRORS);
 592                 goto drop;
 593         }
 594
 595         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 596         if (pkt_len <= IPV6_MAXPLEN) {
 597                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 598                                  IPSTATS_MIB_INHDRERRORS);
 599                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 600                 return 0;
 601         }
 602         if (ipv6_hdr(skb)->payload_len) {
 603                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 604                                  IPSTATS_MIB_INHDRERRORS);
 605                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 606                 return 0;
 607         }
 608
 609         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 610                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 611                                  IPSTATS_MIB_INTRUNCATEDPKTS);
 612                 goto drop;
 613         }
 614
 615         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 616                 goto drop;
 617
 618         return 1;
 619
 620 drop:
 621         kfree_skb(skb);
 622         return 0;
 623 }
 624
 625 static struct tlvtype_proc tlvprochopopt_lst[] = {
 626         {
 627                 .type   = IPV6_TLV_ROUTERALERT,
 628                 .func   = ipv6_hop_ra,
 629         },
 630         {
 631                 .type   = IPV6_TLV_JUMBO,
 632                 .func   = ipv6_hop_jumbo,
 633         },
 634         { -1, }
 635 };
 636
 637 int ipv6_parse_hopopts(struct sk_buff *skb)
 638 {
 639         struct inet6_skb_parm *opt = IP6CB(skb);
 640
 641         /*
 642          * skb_network_header(skb) is equal to skb->data, and
 643          * skb_network_header_len(skb) is always equal to
 644          * sizeof(struct ipv6hdr) by definition of
 645          * hop-by-hop options.
 646          */
 647         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 648             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 649                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 650                 kfree_skb(skb);
 651                 return -1;
 652         }
 653
 654         opt->hop = sizeof(struct ipv6hdr);
 655         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
 656                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 657                 opt = IP6CB(skb);
 658                 opt->nhoff = sizeof(struct ipv6hdr);
 659                 return 1;
 660         }
 661         return -1;
 662 }
 663
 664 /*
 665  *      Creating outbound headers.
 666  *
 667  *      "build" functions work when skb is filled from head to tail (datagram)
 668  *      "push"  functions work when headers are added from tail to head (tcp)
 669  *
 670  *      In both cases we assume, that caller reserved enough room
 671  *      for headers.
 672  */
 673
 674 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 675                             struct ipv6_rt_hdr *opt,
 676                             struct in6_addr **addr_p)
 677 {
 678         struct rt0_hdr *phdr, *ihdr;
 679         int hops;
 680
 681         ihdr = (struct rt0_hdr *) opt;
 682
 683         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 684         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 685
 686         hops = ihdr->rt_hdr.hdrlen >> 1;
 687
 688         if (hops > 1)
 689                 memcpy(phdr->addr, ihdr->addr + 1,
 690                        (hops - 1) * sizeof(struct in6_addr));
 691
 692         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 693         *addr_p = ihdr->addr;
 694
 695         phdr->rt_hdr.nexthdr = *proto;
 696         *proto = NEXTHDR_ROUTING;
 697 }
 698
 699 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 700 {
 701         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 702
 703         memcpy(h, opt, ipv6_optlen(opt));
 704         h->nexthdr = *proto;
 705         *proto = type;
 706 }
 707
 708 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 709                           u8 *proto,
 710                           struct in6_addr **daddr)
 711 {
 712         if (opt->srcrt) {
 713                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 714                 /*
 715                  * IPV6_RTHDRDSTOPTS is ignored
 716                  * unless IPV6_RTHDR is set (RFC3542).
 717                  */
 718                 if (opt->dst0opt)
 719                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 720         }
 721         if (opt->hopopt)
 722                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 723 }
 724
 725 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 726
 727 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 728 {
 729         if (opt->dst1opt)
 730                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 731 }
 732
 733 struct ipv6_txoptions *
 734 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 735 {
 736         struct ipv6_txoptions *opt2;
 737
 738         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 739         if (opt2) {
 740                 long dif = (char*)opt2 - (char*)opt;
 741                 memcpy(opt2, opt, opt->tot_len);
 742                 if (opt2->hopopt)
 743                         *((char**)&opt2->hopopt) += dif;
 744                 if (opt2->dst0opt)
 745                         *((char**)&opt2->dst0opt) += dif;
 746                 if (opt2->dst1opt)
 747                         *((char**)&opt2->dst1opt) += dif;
 748                 if (opt2->srcrt)
 749                         *((char**)&opt2->srcrt) += dif;
 750         }
 751         return opt2;
 752 }
 753
 754 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 755
 756 static int ipv6_renew_option(void *ohdr,
 757                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 758                              int inherit,
 759                              struct ipv6_opt_hdr **hdr,
 760                              char **p)
 761 {
 762         if (inherit) {
 763                 if (ohdr) {
 764                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 765                         *hdr = (struct ipv6_opt_hdr *)*p;
 766                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 767                 }
 768         } else {
 769                 if (newopt) {
 770                         if (copy_from_user(*p, newopt, newoptlen))
 771                                 return -EFAULT;
 772                         *hdr = (struct ipv6_opt_hdr *)*p;
 773                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 774                                 return -EINVAL;
 775                         *p += CMSG_ALIGN(newoptlen);
 776                 }
 777         }
 778         return 0;
 779 }
 780
 781 struct ipv6_txoptions *
 782 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 783                    int newtype,
 784                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 785 {
 786         int tot_len = 0;
 787         char *p;
 788         struct ipv6_txoptions *opt2;
 789         int err;
 790
 791         if (opt) {
 792                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 793                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 794                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 795                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 796                 if (newtype != IPV6_RTHDR && opt->srcrt)
 797                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 798                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 799                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 800         }
 801
 802         if (newopt && newoptlen)
 803                 tot_len += CMSG_ALIGN(newoptlen);
 804
 805         if (!tot_len)
 806                 return NULL;
 807
 808         tot_len += sizeof(*opt2);
 809         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 810         if (!opt2)
 811                 return ERR_PTR(-ENOBUFS);
 812
 813         memset(opt2, 0, tot_len);
 814
 815         opt2->tot_len = tot_len;
 816         p = (char *)(opt2 + 1);
 817
 818         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 819                                 newtype != IPV6_HOPOPTS,
 820                                 &opt2->hopopt, &p);
 821         if (err)
 822                 goto out;
 823
 824         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 825                                 newtype != IPV6_RTHDRDSTOPTS,
 826                                 &opt2->dst0opt, &p);
 827         if (err)
 828                 goto out;
 829
 830         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 831                                 newtype != IPV6_RTHDR,
 832                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 833         if (err)
 834                 goto out;
 835
 836         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 837                                 newtype != IPV6_DSTOPTS,
 838                                 &opt2->dst1opt, &p);
 839         if (err)
 840                 goto out;
 841
 842         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 843                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 844                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 845         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 846
 847         return opt2;
 848 out:
 849         sock_kfree_s(sk, opt2, opt2->tot_len);
 850         return ERR_PTR(err);
 851 }
 852
 853 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 854                                           struct ipv6_txoptions *opt)
 855 {
 856         /*
 857          * ignore the dest before srcrt unless srcrt is being included.
 858          * --yoshfuji
 859          */
 860         if (opt && opt->dst0opt && !opt->srcrt) {
 861                 if (opt_space != opt) {
 862                         memcpy(opt_space, opt, sizeof(*opt_space));
 863                         opt = opt_space;
 864                 }
 865                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 866                 opt->dst0opt = NULL;
 867         }
 868
 869         return opt;
 870 }
 871
 872 /**
 873  * fl6_update_dst - update flowi destination address with info given
 874  *                  by srcrt option, if any.
 875  *
 876  * @fl6: flowi6 for which daddr is to be updated
 877  * @opt: struct ipv6_txoptions in which to look for srcrt opt
 878  * @orig: copy of original daddr address if modified
 879  *
 880  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
 881  * and initial value of fl6->daddr set in orig
 882  */
 883 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
 884                                 const struct ipv6_txoptions *opt,
 885                                 struct in6_addr *orig)
 886 {
 887         if (!opt || !opt->srcrt)
 888                 return NULL;
 889
 890         ipv6_addr_copy(orig, &fl6->daddr);
 891         ipv6_addr_copy(&fl6->daddr, ((struct rt0_hdr *)opt->srcrt)->addr);
 892         return orig;
 893 }
 894
 895 EXPORT_SYMBOL_GPL(fl6_update_dst);