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;
 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(skb_dst(skb)->dev), ip6_dst_idev(skb_dst(skb)),
 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         dst = dst_clone(skb_dst(skb));
 293         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
 294                 dst_release(dst);
 295                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 296                 opt = IP6CB(skb);
 297 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 298                 opt->nhoff = dstbuf;
 299 #else
 300                 opt->nhoff = opt->dst1;
 301 #endif
 302                 return 1;
 303         }
 304
 305         IP6_INC_STATS_BH(dev_net(dst->dev),
 306                          ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 307         dst_release(dst);
 308         return -1;
 309 }
 310
 311 /********************************
 312   Routing header.
 313  ********************************/
 314
 315 /* called with rcu_read_lock() */
 316 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 317 {
 318         struct inet6_skb_parm *opt = IP6CB(skb);
 319         struct in6_addr *addr = NULL;
 320         struct in6_addr daddr;
 321         struct inet6_dev *idev;
 322         int n, i;
 323         struct ipv6_rt_hdr *hdr;
 324         struct rt0_hdr *rthdr;
 325         struct net *net = dev_net(skb->dev);
 326         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 327
 328         idev = __in6_dev_get(skb->dev);
 329         if (idev && accept_source_route > idev->cnf.accept_source_route)
 330                 accept_source_route = idev->cnf.accept_source_route;
 331
 332         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 333             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 334                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 335                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 336                                  IPSTATS_MIB_INHDRERRORS);
 337                 kfree_skb(skb);
 338                 return -1;
 339         }
 340
 341         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 342
 343         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 344             skb->pkt_type != PACKET_HOST) {
 345                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 346                                  IPSTATS_MIB_INADDRERRORS);
 347                 kfree_skb(skb);
 348                 return -1;
 349         }
 350
 351 looped_back:
 352         if (hdr->segments_left == 0) {
 353                 switch (hdr->type) {
 354 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 355                 case IPV6_SRCRT_TYPE_2:
 356                         /* Silently discard type 2 header unless it was
 357                          * processed by own
 358                          */
 359                         if (!addr) {
 360                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 361                                                  IPSTATS_MIB_INADDRERRORS);
 362                                 kfree_skb(skb);
 363                                 return -1;
 364                         }
 365                         break;
 366 #endif
 367                 default:
 368                         break;
 369                 }
 370
 371                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 372                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 373                 opt->dst0 = opt->dst1;
 374                 opt->dst1 = 0;
 375                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 376                 return 1;
 377         }
 378
 379         switch (hdr->type) {
 380 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 381         case IPV6_SRCRT_TYPE_2:
 382                 if (accept_source_route < 0)
 383                         goto unknown_rh;
 384                 /* Silently discard invalid RTH type 2 */
 385                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 386                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 387                                          IPSTATS_MIB_INHDRERRORS);
 388                         kfree_skb(skb);
 389                         return -1;
 390                 }
 391                 break;
 392 #endif
 393         default:
 394                 goto unknown_rh;
 395         }
 396
 397         /*
 398          *      This is the routing header forwarding algorithm from
 399          *      RFC 2460, page 16.
 400          */
 401
 402         n = hdr->hdrlen >> 1;
 403
 404         if (hdr->segments_left > n) {
 405                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 406                                  IPSTATS_MIB_INHDRERRORS);
 407                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 408                                   ((&hdr->segments_left) -
 409                                    skb_network_header(skb)));
 410                 return -1;
 411         }
 412
 413         /* We are about to mangle packet header. Be careful!
 414            Do not damage packets queued somewhere.
 415          */
 416         if (skb_cloned(skb)) {
 417                 /* the copy is a forwarded packet */
 418                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 419                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 420                                          IPSTATS_MIB_OUTDISCARDS);
 421                         kfree_skb(skb);
 422                         return -1;
 423                 }
 424                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 425         }
 426
 427         if (skb->ip_summed == CHECKSUM_COMPLETE)
 428                 skb->ip_summed = CHECKSUM_NONE;
 429
 430         i = n - --hdr->segments_left;
 431
 432         rthdr = (struct rt0_hdr *) hdr;
 433         addr = rthdr->addr;
 434         addr += i - 1;
 435
 436         switch (hdr->type) {
 437 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 438         case IPV6_SRCRT_TYPE_2:
 439                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 440                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 441                                      IPPROTO_ROUTING) < 0) {
 442                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 443                                          IPSTATS_MIB_INADDRERRORS);
 444                         kfree_skb(skb);
 445                         return -1;
 446                 }
 447                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 448                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 449                                          IPSTATS_MIB_INADDRERRORS);
 450                         kfree_skb(skb);
 451                         return -1;
 452                 }
 453                 break;
 454 #endif
 455         default:
 456                 break;
 457         }
 458
 459         if (ipv6_addr_is_multicast(addr)) {
 460                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 461                                  IPSTATS_MIB_INADDRERRORS);
 462                 kfree_skb(skb);
 463                 return -1;
 464         }
 465
 466         ipv6_addr_copy(&daddr, addr);
 467         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 468         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 469
 470         skb_dst_drop(skb);
 471         ip6_route_input(skb);
 472         if (skb_dst(skb)->error) {
 473                 skb_push(skb, skb->data - skb_network_header(skb));
 474                 dst_input(skb);
 475                 return -1;
 476         }
 477
 478         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 479                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 480                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 481                                          IPSTATS_MIB_INHDRERRORS);
 482                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 483                                     0);
 484                         kfree_skb(skb);
 485                         return -1;
 486                 }
 487                 ipv6_hdr(skb)->hop_limit--;
 488                 goto looped_back;
 489         }
 490
 491         skb_push(skb, skb->data - skb_network_header(skb));
 492         dst_input(skb);
 493         return -1;
 494
 495 unknown_rh:
 496         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 497         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 498                           (&hdr->type) - skb_network_header(skb));
 499         return -1;
 500 }
 501
 502 static const struct inet6_protocol rthdr_protocol = {
 503         .handler        =       ipv6_rthdr_rcv,
 504         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 505 };
 506
 507 static const struct inet6_protocol destopt_protocol = {
 508         .handler        =       ipv6_destopt_rcv,
 509         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 510 };
 511
 512 static const struct inet6_protocol nodata_protocol = {
 513         .handler        =       dst_discard,
 514         .flags          =       INET6_PROTO_NOPOLICY,
 515 };
 516
 517 int __init ipv6_exthdrs_init(void)
 518 {
 519         int ret;
 520
 521         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 522         if (ret)
 523                 goto out;
 524
 525         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 526         if (ret)
 527                 goto out_rthdr;
 528
 529         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 530         if (ret)
 531                 goto out_destopt;
 532
 533 out:
 534         return ret;
 535 out_rthdr:
 536         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 537 out_destopt:
 538         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 539         goto out;
 540 };
 541
 542 void ipv6_exthdrs_exit(void)
 543 {
 544         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 545         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 546         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 547 }
 548
 549 /**********************************
 550   Hop-by-hop options.
 551  **********************************/
 552
 553 /*
 554  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 555  */
 556 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 557 {
 558         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 559 }
 560
 561 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 562 {
 563         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 564 }
 565
 566 /* Router Alert as of RFC 2711 */
 567
 568 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 569 {
 570         const unsigned char *nh = skb_network_header(skb);
 571
 572         if (nh[optoff + 1] == 2) {
 573                 IP6CB(skb)->ra = optoff;
 574                 return 1;
 575         }
 576         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 577                        nh[optoff + 1]);
 578         kfree_skb(skb);
 579         return 0;
 580 }
 581
 582 /* Jumbo payload */
 583
 584 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 585 {
 586         const unsigned char *nh = skb_network_header(skb);
 587         struct net *net = ipv6_skb_net(skb);
 588         u32 pkt_len;
 589
 590         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 591                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 592                                nh[optoff+1]);
 593                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 594                                  IPSTATS_MIB_INHDRERRORS);
 595                 goto drop;
 596         }
 597
 598         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 599         if (pkt_len <= IPV6_MAXPLEN) {
 600                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 601                                  IPSTATS_MIB_INHDRERRORS);
 602                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 603                 return 0;
 604         }
 605         if (ipv6_hdr(skb)->payload_len) {
 606                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 607                                  IPSTATS_MIB_INHDRERRORS);
 608                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 609                 return 0;
 610         }
 611
 612         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 613                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 614                                  IPSTATS_MIB_INTRUNCATEDPKTS);
 615                 goto drop;
 616         }
 617
 618         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 619                 goto drop;
 620
 621         return 1;
 622
 623 drop:
 624         kfree_skb(skb);
 625         return 0;
 626 }
 627
 628 static struct tlvtype_proc tlvprochopopt_lst[] = {
 629         {
 630                 .type   = IPV6_TLV_ROUTERALERT,
 631                 .func   = ipv6_hop_ra,
 632         },
 633         {
 634                 .type   = IPV6_TLV_JUMBO,
 635                 .func   = ipv6_hop_jumbo,
 636         },
 637         { -1, }
 638 };
 639
 640 int ipv6_parse_hopopts(struct sk_buff *skb)
 641 {
 642         struct inet6_skb_parm *opt = IP6CB(skb);
 643
 644         /*
 645          * skb_network_header(skb) is equal to skb->data, and
 646          * skb_network_header_len(skb) is always equal to
 647          * sizeof(struct ipv6hdr) by definition of
 648          * hop-by-hop options.
 649          */
 650         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 651             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 652                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 653                 kfree_skb(skb);
 654                 return -1;
 655         }
 656
 657         opt->hop = sizeof(struct ipv6hdr);
 658         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
 659                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 660                 opt = IP6CB(skb);
 661                 opt->nhoff = sizeof(struct ipv6hdr);
 662                 return 1;
 663         }
 664         return -1;
 665 }
 666
 667 /*
 668  *      Creating outbound headers.
 669  *
 670  *      "build" functions work when skb is filled from head to tail (datagram)
 671  *      "push"  functions work when headers are added from tail to head (tcp)
 672  *
 673  *      In both cases we assume, that caller reserved enough room
 674  *      for headers.
 675  */
 676
 677 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 678                             struct ipv6_rt_hdr *opt,
 679                             struct in6_addr **addr_p)
 680 {
 681         struct rt0_hdr *phdr, *ihdr;
 682         int hops;
 683
 684         ihdr = (struct rt0_hdr *) opt;
 685
 686         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 687         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 688
 689         hops = ihdr->rt_hdr.hdrlen >> 1;
 690
 691         if (hops > 1)
 692                 memcpy(phdr->addr, ihdr->addr + 1,
 693                        (hops - 1) * sizeof(struct in6_addr));
 694
 695         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 696         *addr_p = ihdr->addr;
 697
 698         phdr->rt_hdr.nexthdr = *proto;
 699         *proto = NEXTHDR_ROUTING;
 700 }
 701
 702 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 703 {
 704         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 705
 706         memcpy(h, opt, ipv6_optlen(opt));
 707         h->nexthdr = *proto;
 708         *proto = type;
 709 }
 710
 711 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 712                           u8 *proto,
 713                           struct in6_addr **daddr)
 714 {
 715         if (opt->srcrt) {
 716                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 717                 /*
 718                  * IPV6_RTHDRDSTOPTS is ignored
 719                  * unless IPV6_RTHDR is set (RFC3542).
 720                  */
 721                 if (opt->dst0opt)
 722                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 723         }
 724         if (opt->hopopt)
 725                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 726 }
 727
 728 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 729
 730 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 731 {
 732         if (opt->dst1opt)
 733                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 734 }
 735
 736 struct ipv6_txoptions *
 737 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 738 {
 739         struct ipv6_txoptions *opt2;
 740
 741         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 742         if (opt2) {
 743                 long dif = (char*)opt2 - (char*)opt;
 744                 memcpy(opt2, opt, opt->tot_len);
 745                 if (opt2->hopopt)
 746                         *((char**)&opt2->hopopt) += dif;
 747                 if (opt2->dst0opt)
 748                         *((char**)&opt2->dst0opt) += dif;
 749                 if (opt2->dst1opt)
 750                         *((char**)&opt2->dst1opt) += dif;
 751                 if (opt2->srcrt)
 752                         *((char**)&opt2->srcrt) += dif;
 753         }
 754         return opt2;
 755 }
 756
 757 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 758
 759 static int ipv6_renew_option(void *ohdr,
 760                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 761                              int inherit,
 762                              struct ipv6_opt_hdr **hdr,
 763                              char **p)
 764 {
 765         if (inherit) {
 766                 if (ohdr) {
 767                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 768                         *hdr = (struct ipv6_opt_hdr *)*p;
 769                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 770                 }
 771         } else {
 772                 if (newopt) {
 773                         if (copy_from_user(*p, newopt, newoptlen))
 774                                 return -EFAULT;
 775                         *hdr = (struct ipv6_opt_hdr *)*p;
 776                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 777                                 return -EINVAL;
 778                         *p += CMSG_ALIGN(newoptlen);
 779                 }
 780         }
 781         return 0;
 782 }
 783
 784 struct ipv6_txoptions *
 785 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 786                    int newtype,
 787                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 788 {
 789         int tot_len = 0;
 790         char *p;
 791         struct ipv6_txoptions *opt2;
 792         int err;
 793
 794         if (opt) {
 795                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 796                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 797                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 798                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 799                 if (newtype != IPV6_RTHDR && opt->srcrt)
 800                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 801                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 802                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 803         }
 804
 805         if (newopt && newoptlen)
 806                 tot_len += CMSG_ALIGN(newoptlen);
 807
 808         if (!tot_len)
 809                 return NULL;
 810
 811         tot_len += sizeof(*opt2);
 812         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 813         if (!opt2)
 814                 return ERR_PTR(-ENOBUFS);
 815
 816         memset(opt2, 0, tot_len);
 817
 818         opt2->tot_len = tot_len;
 819         p = (char *)(opt2 + 1);
 820
 821         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 822                                 newtype != IPV6_HOPOPTS,
 823                                 &opt2->hopopt, &p);
 824         if (err)
 825                 goto out;
 826
 827         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 828                                 newtype != IPV6_RTHDRDSTOPTS,
 829                                 &opt2->dst0opt, &p);
 830         if (err)
 831                 goto out;
 832
 833         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 834                                 newtype != IPV6_RTHDR,
 835                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 836         if (err)
 837                 goto out;
 838
 839         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 840                                 newtype != IPV6_DSTOPTS,
 841                                 &opt2->dst1opt, &p);
 842         if (err)
 843                 goto out;
 844
 845         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 846                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 847                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 848         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 849
 850         return opt2;
 851 out:
 852         sock_kfree_s(sk, opt2, opt2->tot_len);
 853         return ERR_PTR(err);
 854 }
 855
 856 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 857                                           struct ipv6_txoptions *opt)
 858 {
 859         /*
 860          * ignore the dest before srcrt unless srcrt is being included.
 861          * --yoshfuji
 862          */
 863         if (opt && opt->dst0opt && !opt->srcrt) {
 864                 if (opt_space != opt) {
 865                         memcpy(opt_space, opt, sizeof(*opt_space));
 866                         opt = opt_space;
 867                 }
 868                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 869                 opt->dst0opt = NULL;
 870         }
 871
 872         return opt;
 873 }
 874
 875 /**
 876  * fl6_update_dst - update flowi destination address with info given
 877  *                  by srcrt option, if any.
 878  *
 879  * @fl: flowi for which fl6_dst is to be updated
 880  * @opt: struct ipv6_txoptions in which to look for srcrt opt
 881  * @orig: copy of original fl6_dst address if modified
 882  *
 883  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
 884  * and initial value of fl->fl6_dst set in orig
 885  */
 886 struct in6_addr *fl6_update_dst(struct flowi *fl,
 887                                 const struct ipv6_txoptions *opt,
 888                                 struct in6_addr *orig)
 889 {
 890         if (!opt || !opt->srcrt)
 891                 return NULL;
 892
 893         ipv6_addr_copy(orig, &fl->fl6_dst);
 894         ipv6_addr_copy(&fl->fl6_dst, ((struct rt0_hdr *)opt->srcrt)->addr);
 895         return orig;
 896 }
 897
 898 EXPORT_SYMBOL_GPL(fl6_update_dst);