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