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 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 316 {
 317         struct inet6_skb_parm *opt = IP6CB(skb);
 318         struct in6_addr *addr = NULL;
 319         struct in6_addr daddr;
 320         struct inet6_dev *idev;
 321         int n, i;
 322         struct ipv6_rt_hdr *hdr;
 323         struct rt0_hdr *rthdr;
 324         struct net *net = dev_net(skb->dev);
 325         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 326
 327         idev = in6_dev_get(skb->dev);
 328         if (idev) {
 329                 if (accept_source_route > idev->cnf.accept_source_route)
 330                         accept_source_route = idev->cnf.accept_source_route;
 331                 in6_dev_put(idev);
 332         }
 333
 334         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 335             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 336                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 337                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 338                                  IPSTATS_MIB_INHDRERRORS);
 339                 kfree_skb(skb);
 340                 return -1;
 341         }
 342
 343         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 344
 345         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 346             skb->pkt_type != PACKET_HOST) {
 347                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 348                                  IPSTATS_MIB_INADDRERRORS);
 349                 kfree_skb(skb);
 350                 return -1;
 351         }
 352
 353 looped_back:
 354         if (hdr->segments_left == 0) {
 355                 switch (hdr->type) {
 356 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 357                 case IPV6_SRCRT_TYPE_2:
 358                         /* Silently discard type 2 header unless it was
 359                          * processed by own
 360                          */
 361                         if (!addr) {
 362                                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 363                                                  IPSTATS_MIB_INADDRERRORS);
 364                                 kfree_skb(skb);
 365                                 return -1;
 366                         }
 367                         break;
 368 #endif
 369                 default:
 370                         break;
 371                 }
 372
 373                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 374                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 375                 opt->dst0 = opt->dst1;
 376                 opt->dst1 = 0;
 377                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 378                 return 1;
 379         }
 380
 381         switch (hdr->type) {
 382 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 383         case IPV6_SRCRT_TYPE_2:
 384                 if (accept_source_route < 0)
 385                         goto unknown_rh;
 386                 /* Silently discard invalid RTH type 2 */
 387                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 388                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 389                                          IPSTATS_MIB_INHDRERRORS);
 390                         kfree_skb(skb);
 391                         return -1;
 392                 }
 393                 break;
 394 #endif
 395         default:
 396                 goto unknown_rh;
 397         }
 398
 399         /*
 400          *      This is the routing header forwarding algorithm from
 401          *      RFC 2460, page 16.
 402          */
 403
 404         n = hdr->hdrlen >> 1;
 405
 406         if (hdr->segments_left > n) {
 407                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 408                                  IPSTATS_MIB_INHDRERRORS);
 409                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 410                                   ((&hdr->segments_left) -
 411                                    skb_network_header(skb)));
 412                 return -1;
 413         }
 414
 415         /* We are about to mangle packet header. Be careful!
 416            Do not damage packets queued somewhere.
 417          */
 418         if (skb_cloned(skb)) {
 419                 /* the copy is a forwarded packet */
 420                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 421                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 422                                          IPSTATS_MIB_OUTDISCARDS);
 423                         kfree_skb(skb);
 424                         return -1;
 425                 }
 426                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 427         }
 428
 429         if (skb->ip_summed == CHECKSUM_COMPLETE)
 430                 skb->ip_summed = CHECKSUM_NONE;
 431
 432         i = n - --hdr->segments_left;
 433
 434         rthdr = (struct rt0_hdr *) hdr;
 435         addr = rthdr->addr;
 436         addr += i - 1;
 437
 438         switch (hdr->type) {
 439 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 440         case IPV6_SRCRT_TYPE_2:
 441                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 442                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 443                                      IPPROTO_ROUTING) < 0) {
 444                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 445                                          IPSTATS_MIB_INADDRERRORS);
 446                         kfree_skb(skb);
 447                         return -1;
 448                 }
 449                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 450                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 451                                          IPSTATS_MIB_INADDRERRORS);
 452                         kfree_skb(skb);
 453                         return -1;
 454                 }
 455                 break;
 456 #endif
 457         default:
 458                 break;
 459         }
 460
 461         if (ipv6_addr_is_multicast(addr)) {
 462                 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 463                                  IPSTATS_MIB_INADDRERRORS);
 464                 kfree_skb(skb);
 465                 return -1;
 466         }
 467
 468         ipv6_addr_copy(&daddr, addr);
 469         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 470         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 471
 472         skb_dst_drop(skb);
 473         ip6_route_input(skb);
 474         if (skb_dst(skb)->error) {
 475                 skb_push(skb, skb->data - skb_network_header(skb));
 476                 dst_input(skb);
 477                 return -1;
 478         }
 479
 480         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 481                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 482                         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)),
 483                                          IPSTATS_MIB_INHDRERRORS);
 484                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 485                                     0);
 486                         kfree_skb(skb);
 487                         return -1;
 488                 }
 489                 ipv6_hdr(skb)->hop_limit--;
 490                 goto looped_back;
 491         }
 492
 493         skb_push(skb, skb->data - skb_network_header(skb));
 494         dst_input(skb);
 495         return -1;
 496
 497 unknown_rh:
 498         IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS);
 499         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 500                           (&hdr->type) - skb_network_header(skb));
 501         return -1;
 502 }
 503
 504 static const struct inet6_protocol rthdr_protocol = {
 505         .handler        =       ipv6_rthdr_rcv,
 506         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 507 };
 508
 509 static const struct inet6_protocol destopt_protocol = {
 510         .handler        =       ipv6_destopt_rcv,
 511         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 512 };
 513
 514 static const struct inet6_protocol nodata_protocol = {
 515         .handler        =       dst_discard,
 516         .flags          =       INET6_PROTO_NOPOLICY,
 517 };
 518
 519 int __init ipv6_exthdrs_init(void)
 520 {
 521         int ret;
 522
 523         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 524         if (ret)
 525                 goto out;
 526
 527         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 528         if (ret)
 529                 goto out_rthdr;
 530
 531         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 532         if (ret)
 533                 goto out_destopt;
 534
 535 out:
 536         return ret;
 537 out_rthdr:
 538         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 539 out_destopt:
 540         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 541         goto out;
 542 };
 543
 544 void ipv6_exthdrs_exit(void)
 545 {
 546         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 547         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 548         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 549 }
 550
 551 /**********************************
 552   Hop-by-hop options.
 553  **********************************/
 554
 555 /*
 556  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 557  */
 558 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 559 {
 560         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 561 }
 562
 563 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 564 {
 565         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 566 }
 567
 568 /* Router Alert as of RFC 2711 */
 569
 570 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 571 {
 572         const unsigned char *nh = skb_network_header(skb);
 573
 574         if (nh[optoff + 1] == 2) {
 575                 IP6CB(skb)->ra = optoff;
 576                 return 1;
 577         }
 578         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 579                        nh[optoff + 1]);
 580         kfree_skb(skb);
 581         return 0;
 582 }
 583
 584 /* Jumbo payload */
 585
 586 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 587 {
 588         const unsigned char *nh = skb_network_header(skb);
 589         struct net *net = ipv6_skb_net(skb);
 590         u32 pkt_len;
 591
 592         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 593                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 594                                nh[optoff+1]);
 595                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 596                                  IPSTATS_MIB_INHDRERRORS);
 597                 goto drop;
 598         }
 599
 600         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 601         if (pkt_len <= IPV6_MAXPLEN) {
 602                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 603                                  IPSTATS_MIB_INHDRERRORS);
 604                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 605                 return 0;
 606         }
 607         if (ipv6_hdr(skb)->payload_len) {
 608                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 609                                  IPSTATS_MIB_INHDRERRORS);
 610                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 611                 return 0;
 612         }
 613
 614         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 615                 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb),
 616                                  IPSTATS_MIB_INTRUNCATEDPKTS);
 617                 goto drop;
 618         }
 619
 620         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 621                 goto drop;
 622
 623         return 1;
 624
 625 drop:
 626         kfree_skb(skb);
 627         return 0;
 628 }
 629
 630 static struct tlvtype_proc tlvprochopopt_lst[] = {
 631         {
 632                 .type   = IPV6_TLV_ROUTERALERT,
 633                 .func   = ipv6_hop_ra,
 634         },
 635         {
 636                 .type   = IPV6_TLV_JUMBO,
 637                 .func   = ipv6_hop_jumbo,
 638         },
 639         { -1, }
 640 };
 641
 642 int ipv6_parse_hopopts(struct sk_buff *skb)
 643 {
 644         struct inet6_skb_parm *opt = IP6CB(skb);
 645
 646         /*
 647          * skb_network_header(skb) is equal to skb->data, and
 648          * skb_network_header_len(skb) is always equal to
 649          * sizeof(struct ipv6hdr) by definition of
 650          * hop-by-hop options.
 651          */
 652         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 653             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 654                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 655                 kfree_skb(skb);
 656                 return -1;
 657         }
 658
 659         opt->hop = sizeof(struct ipv6hdr);
 660         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
 661                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 662                 opt = IP6CB(skb);
 663                 opt->nhoff = sizeof(struct ipv6hdr);
 664                 return 1;
 665         }
 666         return -1;
 667 }
 668
 669 /*
 670  *      Creating outbound headers.
 671  *
 672  *      "build" functions work when skb is filled from head to tail (datagram)
 673  *      "push"  functions work when headers are added from tail to head (tcp)
 674  *
 675  *      In both cases we assume, that caller reserved enough room
 676  *      for headers.
 677  */
 678
 679 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 680                             struct ipv6_rt_hdr *opt,
 681                             struct in6_addr **addr_p)
 682 {
 683         struct rt0_hdr *phdr, *ihdr;
 684         int hops;
 685
 686         ihdr = (struct rt0_hdr *) opt;
 687
 688         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 689         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 690
 691         hops = ihdr->rt_hdr.hdrlen >> 1;
 692
 693         if (hops > 1)
 694                 memcpy(phdr->addr, ihdr->addr + 1,
 695                        (hops - 1) * sizeof(struct in6_addr));
 696
 697         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 698         *addr_p = ihdr->addr;
 699
 700         phdr->rt_hdr.nexthdr = *proto;
 701         *proto = NEXTHDR_ROUTING;
 702 }
 703
 704 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 705 {
 706         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 707
 708         memcpy(h, opt, ipv6_optlen(opt));
 709         h->nexthdr = *proto;
 710         *proto = type;
 711 }
 712
 713 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 714                           u8 *proto,
 715                           struct in6_addr **daddr)
 716 {
 717         if (opt->srcrt) {
 718                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 719                 /*
 720                  * IPV6_RTHDRDSTOPTS is ignored
 721                  * unless IPV6_RTHDR is set (RFC3542).
 722                  */
 723                 if (opt->dst0opt)
 724                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 725         }
 726         if (opt->hopopt)
 727                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 728 }
 729
 730 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 731
 732 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 733 {
 734         if (opt->dst1opt)
 735                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 736 }
 737
 738 struct ipv6_txoptions *
 739 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 740 {
 741         struct ipv6_txoptions *opt2;
 742
 743         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 744         if (opt2) {
 745                 long dif = (char*)opt2 - (char*)opt;
 746                 memcpy(opt2, opt, opt->tot_len);
 747                 if (opt2->hopopt)
 748                         *((char**)&opt2->hopopt) += dif;
 749                 if (opt2->dst0opt)
 750                         *((char**)&opt2->dst0opt) += dif;
 751                 if (opt2->dst1opt)
 752                         *((char**)&opt2->dst1opt) += dif;
 753                 if (opt2->srcrt)
 754                         *((char**)&opt2->srcrt) += dif;
 755         }
 756         return opt2;
 757 }
 758
 759 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 760
 761 static int ipv6_renew_option(void *ohdr,
 762                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 763                              int inherit,
 764                              struct ipv6_opt_hdr **hdr,
 765                              char **p)
 766 {
 767         if (inherit) {
 768                 if (ohdr) {
 769                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 770                         *hdr = (struct ipv6_opt_hdr *)*p;
 771                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 772                 }
 773         } else {
 774                 if (newopt) {
 775                         if (copy_from_user(*p, newopt, newoptlen))
 776                                 return -EFAULT;
 777                         *hdr = (struct ipv6_opt_hdr *)*p;
 778                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 779                                 return -EINVAL;
 780                         *p += CMSG_ALIGN(newoptlen);
 781                 }
 782         }
 783         return 0;
 784 }
 785
 786 struct ipv6_txoptions *
 787 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 788                    int newtype,
 789                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 790 {
 791         int tot_len = 0;
 792         char *p;
 793         struct ipv6_txoptions *opt2;
 794         int err;
 795
 796         if (opt) {
 797                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 798                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 799                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 800                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 801                 if (newtype != IPV6_RTHDR && opt->srcrt)
 802                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 803                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 804                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 805         }
 806
 807         if (newopt && newoptlen)
 808                 tot_len += CMSG_ALIGN(newoptlen);
 809
 810         if (!tot_len)
 811                 return NULL;
 812
 813         tot_len += sizeof(*opt2);
 814         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 815         if (!opt2)
 816                 return ERR_PTR(-ENOBUFS);
 817
 818         memset(opt2, 0, tot_len);
 819
 820         opt2->tot_len = tot_len;
 821         p = (char *)(opt2 + 1);
 822
 823         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 824                                 newtype != IPV6_HOPOPTS,
 825                                 &opt2->hopopt, &p);
 826         if (err)
 827                 goto out;
 828
 829         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 830                                 newtype != IPV6_RTHDRDSTOPTS,
 831                                 &opt2->dst0opt, &p);
 832         if (err)
 833                 goto out;
 834
 835         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 836                                 newtype != IPV6_RTHDR,
 837                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 838         if (err)
 839                 goto out;
 840
 841         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 842                                 newtype != IPV6_DSTOPTS,
 843                                 &opt2->dst1opt, &p);
 844         if (err)
 845                 goto out;
 846
 847         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 848                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 849                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 850         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 851
 852         return opt2;
 853 out:
 854         sock_kfree_s(sk, opt2, opt2->tot_len);
 855         return ERR_PTR(err);
 856 }
 857
 858 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 859                                           struct ipv6_txoptions *opt)
 860 {
 861         /*
 862          * ignore the dest before srcrt unless srcrt is being included.
 863          * --yoshfuji
 864          */
 865         if (opt && opt->dst0opt && !opt->srcrt) {
 866                 if (opt_space != opt) {
 867                         memcpy(opt_space, opt, sizeof(*opt_space));
 868                         opt = opt_space;
 869                 }
 870                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 871                 opt->dst0opt = NULL;
 872         }
 873
 874         return opt;
 875 }
 876