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
  33 #include <net/dst.h>
  34 #include <net/sock.h>
  35 #include <net/snmp.h>
  36
  37 #include <net/ipv6.h>
  38 #include <net/protocol.h>
  39 #include <net/transp_v6.h>
  40 #include <net/rawv6.h>
  41 #include <net/ndisc.h>
  42 #include <net/ip6_route.h>
  43 #include <net/addrconf.h>
  44 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
  45 #include <net/xfrm.h>
  46 #endif
  47
  48 #include <asm/uaccess.h>
  49
  50 int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
  51 {
  52         const unsigned char *nh = skb_network_header(skb);
  53         int packet_len = skb->tail - skb->network_header;
  54         struct ipv6_opt_hdr *hdr;
  55         int len;
  56
  57         if (offset + 2 > packet_len)
  58                 goto bad;
  59         hdr = (struct ipv6_opt_hdr *)(nh + offset);
  60         len = ((hdr->hdrlen + 1) << 3);
  61
  62         if (offset + len > packet_len)
  63                 goto bad;
  64
  65         offset += 2;
  66         len -= 2;
  67
  68         while (len > 0) {
  69                 int opttype = nh[offset];
  70                 int optlen;
  71
  72                 if (opttype == type)
  73                         return offset;
  74
  75                 switch (opttype) {
  76                 case IPV6_TLV_PAD0:
  77                         optlen = 1;
  78                         break;
  79                 default:
  80                         optlen = nh[offset + 1] + 2;
  81                         if (optlen > len)
  82                                 goto bad;
  83                         break;
  84                 }
  85                 offset += optlen;
  86                 len -= optlen;
  87         }
  88         /* not_found */
  89  bad:
  90         return -1;
  91 }
  92 EXPORT_SYMBOL_GPL(ipv6_find_tlv);
  93
  94 /*
  95  *      Parsing tlv encoded headers.
  96  *
  97  *      Parsing function "func" returns 1, if parsing succeed
  98  *      and 0, if it failed.
  99  *      It MUST NOT touch skb->h.
 100  */
 101
 102 struct tlvtype_proc {
 103         int     type;
 104         int     (*func)(struct sk_buff *skb, int offset);
 105 };
 106
 107 /*********************
 108   Generic functions
 109  *********************/
 110
 111 /* An unknown option is detected, decide what to do */
 112
 113 static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
 114 {
 115         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
 116         case 0: /* ignore */
 117                 return 1;
 118
 119         case 1: /* drop packet */
 120                 break;
 121
 122         case 3: /* Send ICMP if not a multicast address and drop packet */
 123                 /* Actually, it is redundant check. icmp_send
 124                    will recheck in any case.
 125                  */
 126                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
 127                         break;
 128         case 2: /* send ICMP PARM PROB regardless and drop packet */
 129                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
 130                 return 0;
 131         }
 132
 133         kfree_skb(skb);
 134         return 0;
 135 }
 136
 137 /* Parse tlv encoded option header (hop-by-hop or destination) */
 138
 139 static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
 140 {
 141         struct tlvtype_proc *curr;
 142         const unsigned char *nh = skb_network_header(skb);
 143         int off = skb_network_header_len(skb);
 144         int len = (skb_transport_header(skb)[1] + 1) << 3;
 145
 146         if (skb_transport_offset(skb) + len > skb_headlen(skb))
 147                 goto bad;
 148
 149         off += 2;
 150         len -= 2;
 151
 152         while (len > 0) {
 153                 int optlen = nh[off + 1] + 2;
 154
 155                 switch (nh[off]) {
 156                 case IPV6_TLV_PAD0:
 157                         optlen = 1;
 158                         break;
 159
 160                 case IPV6_TLV_PADN:
 161                         break;
 162
 163                 default: /* Other TLV code so scan list */
 164                         if (optlen > len)
 165                                 goto bad;
 166                         for (curr=procs; curr->type >= 0; curr++) {
 167                                 if (curr->type == nh[off]) {
 168                                         /* type specific length/alignment
 169                                            checks will be performed in the
 170                                            func(). */
 171                                         if (curr->func(skb, off) == 0)
 172                                                 return 0;
 173                                         break;
 174                                 }
 175                         }
 176                         if (curr->type < 0) {
 177                                 if (ip6_tlvopt_unknown(skb, off) == 0)
 178                                         return 0;
 179                         }
 180                         break;
 181                 }
 182                 off += optlen;
 183                 len -= optlen;
 184         }
 185         if (len == 0)
 186                 return 1;
 187 bad:
 188         kfree_skb(skb);
 189         return 0;
 190 }
 191
 192 /*****************************
 193   Destination options header.
 194  *****************************/
 195
 196 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 197 static int ipv6_dest_hao(struct sk_buff *skb, int optoff)
 198 {
 199         struct ipv6_destopt_hao *hao;
 200         struct inet6_skb_parm *opt = IP6CB(skb);
 201         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 202         struct in6_addr tmp_addr;
 203         int ret;
 204
 205         if (opt->dsthao) {
 206                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
 207                 goto discard;
 208         }
 209         opt->dsthao = opt->dst1;
 210         opt->dst1 = 0;
 211
 212         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 213
 214         if (hao->length != 16) {
 215                 LIMIT_NETDEBUG(
 216                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
 217                 goto discard;
 218         }
 219
 220         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 221                 LIMIT_NETDEBUG(
 222                         KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr);
 223                 goto discard;
 224         }
 225
 226         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 227                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 228         if (unlikely(ret < 0))
 229                 goto discard;
 230
 231         if (skb_cloned(skb)) {
 232                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 233                         goto discard;
 234
 235                 /* update all variable using below by copied skbuff */
 236                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
 237                                                   optoff);
 238                 ipv6h = ipv6_hdr(skb);
 239         }
 240
 241         if (skb->ip_summed == CHECKSUM_COMPLETE)
 242                 skb->ip_summed = CHECKSUM_NONE;
 243
 244         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
 245         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
 246         ipv6_addr_copy(&hao->addr, &tmp_addr);
 247
 248         if (skb->tstamp.tv64 == 0)
 249                 __net_timestamp(skb);
 250
 251         return 1;
 252
 253  discard:
 254         kfree_skb(skb);
 255         return 0;
 256 }
 257 #endif
 258
 259 static struct tlvtype_proc tlvprocdestopt_lst[] = {
 260 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 261         {
 262                 .type   = IPV6_TLV_HAO,
 263                 .func   = ipv6_dest_hao,
 264         },
 265 #endif
 266         {-1,                    NULL}
 267 };
 268
 269 static int ipv6_destopt_rcv(struct sk_buff *skb)
 270 {
 271         struct inet6_skb_parm *opt = IP6CB(skb);
 272 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 273         __u16 dstbuf;
 274 #endif
 275         struct dst_entry *dst;
 276
 277         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 278             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 279                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 280                 IP6_INC_STATS_BH(dev_net(skb_dst(skb)->dev), ip6_dst_idev(skb_dst(skb)),
 281                                  IPSTATS_MIB_INHDRERRORS);
 282                 kfree_skb(skb);
 283                 return -1;
 284         }
 285
 286         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 287 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 288         dstbuf = opt->dst1;
 289 #endif
 290
 291         dst = dst_clone(skb_dst(skb));
 292         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
 293                 dst_release(dst);
 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         dst_release(dst);
 307         return -1;
 308 }
 309
 310 /********************************
 311   Routing header.
 312  ********************************/
 313
 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) {
 328                 if (accept_source_route > idev->cnf.accept_source_route)
 329                         accept_source_route = idev->cnf.accept_source_route;
 330                 in6_dev_put(idev);
 331         }
 332
 333         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 334             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 335                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 336                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 337                                  IPSTATS_MIB_INHDRERRORS);
 338                 kfree_skb(skb);
 339                 return -1;
 340         }
 341
 342         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 343
 344         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 345             skb->pkt_type != PACKET_HOST) {
 346                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 347                                  IPSTATS_MIB_INADDRERRORS);
 348                 kfree_skb(skb);
 349                 return -1;
 350         }
 351
 352 looped_back:
 353         if (hdr->segments_left == 0) {
 354                 switch (hdr->type) {
 355 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 356                 case IPV6_SRCRT_TYPE_2:
 357                         /* Silently discard type 2 header unless it was
 358                          * processed by own
 359                          */
 360                         if (!addr) {
 361                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 362                                                  IPSTATS_MIB_INADDRERRORS);
 363                                 kfree_skb(skb);
 364                                 return -1;
 365                         }
 366                         break;
 367 #endif
 368                 default:
 369                         break;
 370                 }
 371
 372                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 373                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 374                 opt->dst0 = opt->dst1;
 375                 opt->dst1 = 0;
 376                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 377                 return 1;
 378         }
 379
 380         switch (hdr->type) {
 381 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 382         case IPV6_SRCRT_TYPE_2:
 383                 if (accept_source_route < 0)
 384                         goto unknown_rh;
 385                 /* Silently discard invalid RTH type 2 */
 386                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 387                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 388                                          IPSTATS_MIB_INHDRERRORS);
 389                         kfree_skb(skb);
 390                         return -1;
 391                 }
 392                 break;
 393 #endif
 394         default:
 395                 goto unknown_rh;
 396         }
 397
 398         /*
 399          *      This is the routing header forwarding algorithm from
 400          *      RFC 2460, page 16.
 401          */
 402
 403         n = hdr->hdrlen >> 1;
 404
 405         if (hdr->segments_left > n) {
 406                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 407                                  IPSTATS_MIB_INHDRERRORS);
 408                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 409                                   ((&hdr->segments_left) -
 410                                    skb_network_header(skb)));
 411                 return -1;
 412         }
 413
 414         /* We are about to mangle packet header. Be careful!
 415            Do not damage packets queued somewhere.
 416          */
 417         if (skb_cloned(skb)) {
 418                 /* the copy is a forwarded packet */
 419                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 420                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 421                                          IPSTATS_MIB_OUTDISCARDS);
 422                         kfree_skb(skb);
 423                         return -1;
 424                 }
 425                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 426         }
 427
 428         if (skb->ip_summed == CHECKSUM_COMPLETE)
 429                 skb->ip_summed = CHECKSUM_NONE;
 430
 431         i = n - --hdr->segments_left;
 432
 433         rthdr = (struct rt0_hdr *) hdr;
 434         addr = rthdr->addr;
 435         addr += i - 1;
 436
 437         switch (hdr->type) {
 438 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 439         case IPV6_SRCRT_TYPE_2:
 440                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 441                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 442                                      IPPROTO_ROUTING) < 0) {
 443                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 444                                          IPSTATS_MIB_INADDRERRORS);
 445                         kfree_skb(skb);
 446                         return -1;
 447                 }
 448                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 449                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 450                                          IPSTATS_MIB_INADDRERRORS);
 451                         kfree_skb(skb);
 452                         return -1;
 453                 }
 454                 break;
 455 #endif
 456         default:
 457                 break;
 458         }
 459
 460         if (ipv6_addr_is_multicast(addr)) {
 461                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 462                                  IPSTATS_MIB_INADDRERRORS);
 463                 kfree_skb(skb);
 464                 return -1;
 465         }
 466
 467         ipv6_addr_copy(&daddr, addr);
 468         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 469         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 470
 471         skb_dst_drop(skb);
 472         ip6_route_input(skb);
 473         if (skb_dst(skb)->error) {
 474                 skb_push(skb, skb->data - skb_network_header(skb));
 475                 dst_input(skb);
 476                 return -1;
 477         }
 478
 479         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 480                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 481                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 482                                          IPSTATS_MIB_INHDRERRORS);
 483                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 484                                     0, skb->dev);
 485                         kfree_skb(skb);
 486                         return -1;
 487                 }
 488                 ipv6_hdr(skb)->hop_limit--;
 489                 goto looped_back;
 490         }
 491
 492         skb_push(skb, skb->data - skb_network_header(skb));
 493         dst_input(skb);
 494         return -1;
 495
 496 unknown_rh:
 497         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 498         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 499                           (&hdr->type) - skb_network_header(skb));
 500         return -1;
 501 }
 502
 503 static const struct inet6_protocol rthdr_protocol = {
 504         .handler        =       ipv6_rthdr_rcv,
 505         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 506 };
 507
 508 static const struct inet6_protocol destopt_protocol = {
 509         .handler        =       ipv6_destopt_rcv,
 510         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 511 };
 512
 513 static const struct inet6_protocol nodata_protocol = {
 514         .handler        =       dst_discard,
 515         .flags          =       INET6_PROTO_NOPOLICY,
 516 };
 517
 518 int __init ipv6_exthdrs_init(void)
 519 {
 520         int ret;
 521
 522         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 523         if (ret)
 524                 goto out;
 525
 526         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 527         if (ret)
 528                 goto out_rthdr;
 529
 530         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 531         if (ret)
 532                 goto out_destopt;
 533
 534 out:
 535         return ret;
 536 out_rthdr:
 537         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 538 out_destopt:
 539         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 540         goto out;
 541 };
 542
 543 void ipv6_exthdrs_exit(void)
 544 {
 545         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 546         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 547         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 548 }
 549
 550 /**********************************
 551   Hop-by-hop options.
 552  **********************************/
 553
 554 /*
 555  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 556  */
 557 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 558 {
 559         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 560 }
 561
 562 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 563 {
 564         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 565 }
 566
 567 /* Router Alert as of RFC 2711 */
 568
 569 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 570 {
 571         const unsigned char *nh = skb_network_header(skb);
 572
 573         if (nh[optoff + 1] == 2) {
 574                 IP6CB(skb)->ra = optoff;
 575                 return 1;
 576         }
 577         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 578                        nh[optoff + 1]);
 579         kfree_skb(skb);
 580         return 0;
 581 }
 582
 583 /* Jumbo payload */
 584
 585 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 586 {
 587         const unsigned char *nh = skb_network_header(skb);
 588         struct net *net = ipv6_skb_net(skb);
 589         u32 pkt_len;
 590
 591         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 592                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 593                                nh[optoff+1]);
 594                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 595                                  IPSTATS_MIB_INHDRERRORS);
 596                 goto drop;
 597         }
 598
 599         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 600         if (pkt_len <= IPV6_MAXPLEN) {
 601                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 602                                  IPSTATS_MIB_INHDRERRORS);
 603                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 604                 return 0;
 605         }
 606         if (ipv6_hdr(skb)->payload_len) {
 607                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 608                                  IPSTATS_MIB_INHDRERRORS);
 609                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 610                 return 0;
 611         }
 612
 613         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 614                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 615                                  IPSTATS_MIB_INTRUNCATEDPKTS);
 616                 goto drop;
 617         }
 618
 619         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 620                 goto drop;
 621
 622         return 1;
 623
 624 drop:
 625         kfree_skb(skb);
 626         return 0;
 627 }
 628
 629 static struct tlvtype_proc tlvprochopopt_lst[] = {
 630         {
 631                 .type   = IPV6_TLV_ROUTERALERT,
 632                 .func   = ipv6_hop_ra,
 633         },
 634         {
 635                 .type   = IPV6_TLV_JUMBO,
 636                 .func   = ipv6_hop_jumbo,
 637         },
 638         { -1, }
 639 };
 640
 641 int ipv6_parse_hopopts(struct sk_buff *skb)
 642 {
 643         struct inet6_skb_parm *opt = IP6CB(skb);
 644
 645         /*
 646          * skb_network_header(skb) is equal to skb->data, and
 647          * skb_network_header_len(skb) is always equal to
 648          * sizeof(struct ipv6hdr) by definition of
 649          * hop-by-hop options.
 650          */
 651         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 652             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 653                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 654                 kfree_skb(skb);
 655                 return -1;
 656         }
 657
 658         opt->hop = sizeof(struct ipv6hdr);
 659         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
 660                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 661                 opt = IP6CB(skb);
 662                 opt->nhoff = sizeof(struct ipv6hdr);
 663                 return 1;
 664         }
 665         return -1;
 666 }
 667
 668 /*
 669  *      Creating outbound headers.
 670  *
 671  *      "build" functions work when skb is filled from head to tail (datagram)
 672  *      "push"  functions work when headers are added from tail to head (tcp)
 673  *
 674  *      In both cases we assume, that caller reserved enough room
 675  *      for headers.
 676  */
 677
 678 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 679                             struct ipv6_rt_hdr *opt,
 680                             struct in6_addr **addr_p)
 681 {
 682         struct rt0_hdr *phdr, *ihdr;
 683         int hops;
 684
 685         ihdr = (struct rt0_hdr *) opt;
 686
 687         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 688         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 689
 690         hops = ihdr->rt_hdr.hdrlen >> 1;
 691
 692         if (hops > 1)
 693                 memcpy(phdr->addr, ihdr->addr + 1,
 694                        (hops - 1) * sizeof(struct in6_addr));
 695
 696         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 697         *addr_p = ihdr->addr;
 698
 699         phdr->rt_hdr.nexthdr = *proto;
 700         *proto = NEXTHDR_ROUTING;
 701 }
 702
 703 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 704 {
 705         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 706
 707         memcpy(h, opt, ipv6_optlen(opt));
 708         h->nexthdr = *proto;
 709         *proto = type;
 710 }
 711
 712 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 713                           u8 *proto,
 714                           struct in6_addr **daddr)
 715 {
 716         if (opt->srcrt) {
 717                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 718                 /*
 719                  * IPV6_RTHDRDSTOPTS is ignored
 720                  * unless IPV6_RTHDR is set (RFC3542).
 721                  */
 722                 if (opt->dst0opt)
 723                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 724         }
 725         if (opt->hopopt)
 726                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 727 }
 728
 729 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 730
 731 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 732 {
 733         if (opt->dst1opt)
 734                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 735 }
 736
 737 struct ipv6_txoptions *
 738 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 739 {
 740         struct ipv6_txoptions *opt2;
 741
 742         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 743         if (opt2) {
 744                 long dif = (char*)opt2 - (char*)opt;
 745                 memcpy(opt2, opt, opt->tot_len);
 746                 if (opt2->hopopt)
 747                         *((char**)&opt2->hopopt) += dif;
 748                 if (opt2->dst0opt)
 749                         *((char**)&opt2->dst0opt) += dif;
 750                 if (opt2->dst1opt)
 751                         *((char**)&opt2->dst1opt) += dif;
 752                 if (opt2->srcrt)
 753                         *((char**)&opt2->srcrt) += dif;
 754         }
 755         return opt2;
 756 }
 757
 758 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 759
 760 static int ipv6_renew_option(void *ohdr,
 761                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 762                              int inherit,
 763                              struct ipv6_opt_hdr **hdr,
 764                              char **p)
 765 {
 766         if (inherit) {
 767                 if (ohdr) {
 768                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 769                         *hdr = (struct ipv6_opt_hdr *)*p;
 770                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 771                 }
 772         } else {
 773                 if (newopt) {
 774                         if (copy_from_user(*p, newopt, newoptlen))
 775                                 return -EFAULT;
 776                         *hdr = (struct ipv6_opt_hdr *)*p;
 777                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 778                                 return -EINVAL;
 779                         *p += CMSG_ALIGN(newoptlen);
 780                 }
 781         }
 782         return 0;
 783 }
 784
 785 struct ipv6_txoptions *
 786 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 787                    int newtype,
 788                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 789 {
 790         int tot_len = 0;
 791         char *p;
 792         struct ipv6_txoptions *opt2;
 793         int err;
 794
 795         if (opt) {
 796                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 797                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 798                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 799                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 800                 if (newtype != IPV6_RTHDR && opt->srcrt)
 801                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 802                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 803                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 804         }
 805
 806         if (newopt && newoptlen)
 807                 tot_len += CMSG_ALIGN(newoptlen);
 808
 809         if (!tot_len)
 810                 return NULL;
 811
 812         tot_len += sizeof(*opt2);
 813         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 814         if (!opt2)
 815                 return ERR_PTR(-ENOBUFS);
 816
 817         memset(opt2, 0, tot_len);
 818
 819         opt2->tot_len = tot_len;
 820         p = (char *)(opt2 + 1);
 821
 822         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 823                                 newtype != IPV6_HOPOPTS,
 824                                 &opt2->hopopt, &p);
 825         if (err)
 826                 goto out;
 827
 828         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 829                                 newtype != IPV6_RTHDRDSTOPTS,
 830                                 &opt2->dst0opt, &p);
 831         if (err)
 832                 goto out;
 833
 834         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 835                                 newtype != IPV6_RTHDR,
 836                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 837         if (err)
 838                 goto out;
 839
 840         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 841                                 newtype != IPV6_DSTOPTS,
 842                                 &opt2->dst1opt, &p);
 843         if (err)
 844                 goto out;
 845
 846         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 847                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 848                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 849         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 850
 851         return opt2;
 852 out:
 853         sock_kfree_s(sk, opt2, opt2->tot_len);
 854         return ERR_PTR(err);
 855 }
 856
 857 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 858                                           struct ipv6_txoptions *opt)
 859 {
 860         /*
 861          * ignore the dest before srcrt unless srcrt is being included.
 862          * --yoshfuji
 863          */
 864         if (opt && opt->dst0opt && !opt->srcrt) {
 865                 if (opt_space != opt) {
 866                         memcpy(opt_space, opt, sizeof(*opt_space));
 867                         opt = opt_space;
 868                 }
 869                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 870                 opt->dst0opt = NULL;
 871         }
 872
 873         return opt;
 874 }
 875