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  *      $Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  */
  17
  18 /* Changes:
  19  *      yoshfuji                : ensure not to overrun while parsing
  20  *                                tlv options.
  21  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
  22  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
  23  *                                handlers as inet6_protocol{}.
  24  */
  25
  26 #include <linux/errno.h>
  27 #include <linux/types.h>
  28 #include <linux/socket.h>
  29 #include <linux/sockios.h>
  30 #include <linux/net.h>
  31 #include <linux/netdevice.h>
  32 #include <linux/in6.h>
  33 #include <linux/icmpv6.h>
  34
  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 #ifdef CONFIG_IPV6_MIP6
  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 - nh;
  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
  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 **skbp, 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 **skbp, int optoff)
 114 {
 115         struct sk_buff *skb = *skbp;
 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 **skbp)
 142 {
 143         struct sk_buff *skb = *skbp;
 144         struct tlvtype_proc *curr;
 145         const unsigned char *nh = skb_network_header(skb);
 146         int off = skb->h.raw - skb->nh.raw;
 147         int len = ((skb->h.raw[1]+1)<<3);
 148
 149         if (skb_transport_offset(skb) + len > skb_headlen(skb))
 150                 goto bad;
 151
 152         off += 2;
 153         len -= 2;
 154
 155         while (len > 0) {
 156                 int optlen = nh[off + 1] + 2;
 157
 158                 switch (nh[off]) {
 159                 case IPV6_TLV_PAD0:
 160                         optlen = 1;
 161                         break;
 162
 163                 case IPV6_TLV_PADN:
 164                         break;
 165
 166                 default: /* Other TLV code so scan list */
 167                         if (optlen > len)
 168                                 goto bad;
 169                         for (curr=procs; curr->type >= 0; curr++) {
 170                                 if (curr->type == nh[off]) {
 171                                         /* type specific length/alignment
 172                                            checks will be performed in the
 173                                            func(). */
 174                                         if (curr->func(skbp, off) == 0)
 175                                                 return 0;
 176                                         break;
 177                                 }
 178                         }
 179                         if (curr->type < 0) {
 180                                 if (ip6_tlvopt_unknown(skbp, off) == 0)
 181                                         return 0;
 182                         }
 183                         break;
 184                 }
 185                 off += optlen;
 186                 len -= optlen;
 187         }
 188         if (len == 0)
 189                 return 1;
 190 bad:
 191         kfree_skb(skb);
 192         return 0;
 193 }
 194
 195 /*****************************
 196   Destination options header.
 197  *****************************/
 198
 199 #ifdef CONFIG_IPV6_MIP6
 200 static int ipv6_dest_hao(struct sk_buff **skbp, int optoff)
 201 {
 202         struct sk_buff *skb = *skbp;
 203         struct ipv6_destopt_hao *hao;
 204         struct inet6_skb_parm *opt = IP6CB(skb);
 205         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 206         struct in6_addr tmp_addr;
 207         int ret;
 208
 209         if (opt->dsthao) {
 210                 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n");
 211                 goto discard;
 212         }
 213         opt->dsthao = opt->dst1;
 214         opt->dst1 = 0;
 215
 216         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 217
 218         if (hao->length != 16) {
 219                 LIMIT_NETDEBUG(
 220                         KERN_DEBUG "hao invalid option length = %d\n", hao->length);
 221                 goto discard;
 222         }
 223
 224         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 225                 LIMIT_NETDEBUG(
 226                         KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr));
 227                 goto discard;
 228         }
 229
 230         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 231                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 232         if (unlikely(ret < 0))
 233                 goto discard;
 234
 235         if (skb_cloned(skb)) {
 236                 struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
 237                 struct inet6_skb_parm *opt2;
 238
 239                 if (skb2 == NULL)
 240                         goto discard;
 241
 242                 opt2 = IP6CB(skb2);
 243                 memcpy(opt2, opt, sizeof(*opt2));
 244
 245                 kfree_skb(skb);
 246
 247                 /* update all variable using below by copied skbuff */
 248                 *skbp = skb = skb2;
 249                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb2) +
 250                                                   optoff);
 251                 ipv6h = ipv6_hdr(skb2);
 252         }
 253
 254         if (skb->ip_summed == CHECKSUM_COMPLETE)
 255                 skb->ip_summed = CHECKSUM_NONE;
 256
 257         ipv6_addr_copy(&tmp_addr, &ipv6h->saddr);
 258         ipv6_addr_copy(&ipv6h->saddr, &hao->addr);
 259         ipv6_addr_copy(&hao->addr, &tmp_addr);
 260
 261         if (skb->tstamp.tv64 == 0)
 262                 __net_timestamp(skb);
 263
 264         return 1;
 265
 266  discard:
 267         kfree_skb(skb);
 268         return 0;
 269 }
 270 #endif
 271
 272 static struct tlvtype_proc tlvprocdestopt_lst[] = {
 273 #ifdef CONFIG_IPV6_MIP6
 274         {
 275                 .type   = IPV6_TLV_HAO,
 276                 .func   = ipv6_dest_hao,
 277         },
 278 #endif
 279         {-1,                    NULL}
 280 };
 281
 282 static int ipv6_destopt_rcv(struct sk_buff **skbp)
 283 {
 284         struct sk_buff *skb = *skbp;
 285         struct inet6_skb_parm *opt = IP6CB(skb);
 286 #ifdef CONFIG_IPV6_MIP6
 287         __u16 dstbuf;
 288 #endif
 289         struct dst_entry *dst;
 290
 291         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 292             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 293                                  ((skb->h.raw[1] + 1) << 3)))) {
 294                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 295                                  IPSTATS_MIB_INHDRERRORS);
 296                 kfree_skb(skb);
 297                 return -1;
 298         }
 299
 300         opt->lastopt = skb->h.raw - skb->nh.raw;
 301         opt->dst1 = skb->h.raw - skb->nh.raw;
 302 #ifdef CONFIG_IPV6_MIP6
 303         dstbuf = opt->dst1;
 304 #endif
 305
 306         dst = dst_clone(skb->dst);
 307         if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) {
 308                 dst_release(dst);
 309                 skb = *skbp;
 310                 skb->h.raw += ((skb->h.raw[1]+1)<<3);
 311                 opt = IP6CB(skb);
 312 #ifdef CONFIG_IPV6_MIP6
 313                 opt->nhoff = dstbuf;
 314 #else
 315                 opt->nhoff = opt->dst1;
 316 #endif
 317                 return 1;
 318         }
 319
 320         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 321         dst_release(dst);
 322         return -1;
 323 }
 324
 325 static struct inet6_protocol destopt_protocol = {
 326         .handler        =       ipv6_destopt_rcv,
 327         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 328 };
 329
 330 void __init ipv6_destopt_init(void)
 331 {
 332         if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
 333                 printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
 334 }
 335
 336 /********************************
 337   NONE header. No data in packet.
 338  ********************************/
 339
 340 static int ipv6_nodata_rcv(struct sk_buff **skbp)
 341 {
 342         struct sk_buff *skb = *skbp;
 343
 344         kfree_skb(skb);
 345         return 0;
 346 }
 347
 348 static struct inet6_protocol nodata_protocol = {
 349         .handler        =       ipv6_nodata_rcv,
 350         .flags          =       INET6_PROTO_NOPOLICY,
 351 };
 352
 353 void __init ipv6_nodata_init(void)
 354 {
 355         if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
 356                 printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
 357 }
 358
 359 /********************************
 360   Routing header.
 361  ********************************/
 362
 363 static int ipv6_rthdr_rcv(struct sk_buff **skbp)
 364 {
 365         struct sk_buff *skb = *skbp;
 366         struct inet6_skb_parm *opt = IP6CB(skb);
 367         struct in6_addr *addr = NULL;
 368         struct in6_addr daddr;
 369         struct inet6_dev *idev;
 370         int n, i;
 371         struct ipv6_rt_hdr *hdr;
 372         struct rt0_hdr *rthdr;
 373         int accept_source_route = ipv6_devconf.accept_source_route;
 374
 375         if (accept_source_route < 0 ||
 376             ((idev = in6_dev_get(skb->dev)) == NULL)) {
 377                 kfree_skb(skb);
 378                 return -1;
 379         }
 380         if (idev->cnf.accept_source_route < 0) {
 381                 in6_dev_put(idev);
 382                 kfree_skb(skb);
 383                 return -1;
 384         }
 385
 386         if (accept_source_route > idev->cnf.accept_source_route)
 387                 accept_source_route = idev->cnf.accept_source_route;
 388
 389         in6_dev_put(idev);
 390
 391         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 392             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 393                                  ((skb->h.raw[1] + 1) << 3)))) {
 394                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 395                                  IPSTATS_MIB_INHDRERRORS);
 396                 kfree_skb(skb);
 397                 return -1;
 398         }
 399
 400         hdr = (struct ipv6_rt_hdr *) skb->h.raw;
 401
 402         switch (hdr->type) {
 403 #ifdef CONFIG_IPV6_MIP6
 404                 break;
 405 #endif
 406         case IPV6_SRCRT_TYPE_0:
 407                 if (accept_source_route > 0)
 408                         break;
 409                 kfree_skb(skb);
 410                 return -1;
 411         default:
 412                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 413                                  IPSTATS_MIB_INHDRERRORS);
 414                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 415                                   (&hdr->type) - skb_network_header(skb));
 416                 return -1;
 417         }
 418
 419         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 420             skb->pkt_type != PACKET_HOST) {
 421                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 422                                  IPSTATS_MIB_INADDRERRORS);
 423                 kfree_skb(skb);
 424                 return -1;
 425         }
 426
 427 looped_back:
 428         if (hdr->segments_left == 0) {
 429                 switch (hdr->type) {
 430 #ifdef CONFIG_IPV6_MIP6
 431                 case IPV6_SRCRT_TYPE_2:
 432                         /* Silently discard type 2 header unless it was
 433                          * processed by own
 434                          */
 435                         if (!addr) {
 436                                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 437                                                  IPSTATS_MIB_INADDRERRORS);
 438                                 kfree_skb(skb);
 439                                 return -1;
 440                         }
 441                         break;
 442 #endif
 443                 default:
 444                         break;
 445                 }
 446
 447                 opt->lastopt = skb->h.raw - skb->nh.raw;
 448                 opt->srcrt = skb->h.raw - skb->nh.raw;
 449                 skb->h.raw += (hdr->hdrlen + 1) << 3;
 450                 opt->dst0 = opt->dst1;
 451                 opt->dst1 = 0;
 452                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 453                 return 1;
 454         }
 455
 456         switch (hdr->type) {
 457         case IPV6_SRCRT_TYPE_0:
 458                 if (hdr->hdrlen & 0x01) {
 459                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 460                                          IPSTATS_MIB_INHDRERRORS);
 461                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 462                                           ((&hdr->hdrlen) -
 463                                            skb_network_header(skb)));
 464                         return -1;
 465                 }
 466                 break;
 467 #ifdef CONFIG_IPV6_MIP6
 468         case IPV6_SRCRT_TYPE_2:
 469                 /* Silently discard invalid RTH type 2 */
 470                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 471                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 472                                          IPSTATS_MIB_INHDRERRORS);
 473                         kfree_skb(skb);
 474                         return -1;
 475                 }
 476                 break;
 477 #endif
 478         }
 479
 480         /*
 481          *      This is the routing header forwarding algorithm from
 482          *      RFC 2460, page 16.
 483          */
 484
 485         n = hdr->hdrlen >> 1;
 486
 487         if (hdr->segments_left > n) {
 488                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 489                                  IPSTATS_MIB_INHDRERRORS);
 490                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 491                                   ((&hdr->segments_left) -
 492                                    skb_network_header(skb)));
 493                 return -1;
 494         }
 495
 496         /* We are about to mangle packet header. Be careful!
 497            Do not damage packets queued somewhere.
 498          */
 499         if (skb_cloned(skb)) {
 500                 struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
 501                 /* the copy is a forwarded packet */
 502                 if (skb2 == NULL) {
 503                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 504                                          IPSTATS_MIB_OUTDISCARDS);
 505                         kfree_skb(skb);
 506                         return -1;
 507                 }
 508                 kfree_skb(skb);
 509                 *skbp = skb = skb2;
 510                 opt = IP6CB(skb2);
 511                 hdr = (struct ipv6_rt_hdr *) skb2->h.raw;
 512         }
 513
 514         if (skb->ip_summed == CHECKSUM_COMPLETE)
 515                 skb->ip_summed = CHECKSUM_NONE;
 516
 517         i = n - --hdr->segments_left;
 518
 519         rthdr = (struct rt0_hdr *) hdr;
 520         addr = rthdr->addr;
 521         addr += i - 1;
 522
 523         switch (hdr->type) {
 524 #ifdef CONFIG_IPV6_MIP6
 525         case IPV6_SRCRT_TYPE_2:
 526                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 527                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 528                                      IPPROTO_ROUTING) < 0) {
 529                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 530                                          IPSTATS_MIB_INADDRERRORS);
 531                         kfree_skb(skb);
 532                         return -1;
 533                 }
 534                 if (!ipv6_chk_home_addr(addr)) {
 535                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 536                                          IPSTATS_MIB_INADDRERRORS);
 537                         kfree_skb(skb);
 538                         return -1;
 539                 }
 540                 break;
 541 #endif
 542         default:
 543                 break;
 544         }
 545
 546         if (ipv6_addr_is_multicast(addr)) {
 547                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 548                                  IPSTATS_MIB_INADDRERRORS);
 549                 kfree_skb(skb);
 550                 return -1;
 551         }
 552
 553         ipv6_addr_copy(&daddr, addr);
 554         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 555         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 556
 557         dst_release(xchg(&skb->dst, NULL));
 558         ip6_route_input(skb);
 559         if (skb->dst->error) {
 560                 skb_push(skb, skb->data - skb_network_header(skb));
 561                 dst_input(skb);
 562                 return -1;
 563         }
 564
 565         if (skb->dst->dev->flags&IFF_LOOPBACK) {
 566                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 567                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 568                                          IPSTATS_MIB_INHDRERRORS);
 569                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 570                                     0, skb->dev);
 571                         kfree_skb(skb);
 572                         return -1;
 573                 }
 574                 ipv6_hdr(skb)->hop_limit--;
 575                 goto looped_back;
 576         }
 577
 578         skb_push(skb, skb->data - skb_network_header(skb));
 579         dst_input(skb);
 580         return -1;
 581 }
 582
 583 static struct inet6_protocol rthdr_protocol = {
 584         .handler        =       ipv6_rthdr_rcv,
 585         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 586 };
 587
 588 void __init ipv6_rthdr_init(void)
 589 {
 590         if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
 591                 printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
 592 };
 593
 594 /*
 595    This function inverts received rthdr.
 596    NOTE: specs allow to make it automatically only if
 597    packet authenticated.
 598
 599    I will not discuss it here (though, I am really pissed off at
 600    this stupid requirement making rthdr idea useless)
 601
 602    Actually, it creates severe problems  for us.
 603    Embryonic requests has no associated sockets,
 604    so that user have no control over it and
 605    cannot not only to set reply options, but
 606    even to know, that someone wants to connect
 607    without success. :-(
 608
 609    For now we need to test the engine, so that I created
 610    temporary (or permanent) backdoor.
 611    If listening socket set IPV6_RTHDR to 2, then we invert header.
 612                                                    --ANK (980729)
 613  */
 614
 615 struct ipv6_txoptions *
 616 ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
 617 {
 618         /* Received rthdr:
 619
 620            [ H1 -> H2 -> ... H_prev ]  daddr=ME
 621
 622            Inverted result:
 623            [ H_prev -> ... -> H1 ] daddr =sender
 624
 625            Note, that IP output engine will rewrite this rthdr
 626            by rotating it left by one addr.
 627          */
 628
 629         int n, i;
 630         struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr;
 631         struct rt0_hdr *irthdr;
 632         struct ipv6_txoptions *opt;
 633         int hdrlen = ipv6_optlen(hdr);
 634
 635         if (hdr->segments_left ||
 636             hdr->type != IPV6_SRCRT_TYPE_0 ||
 637             hdr->hdrlen & 0x01)
 638                 return NULL;
 639
 640         n = hdr->hdrlen >> 1;
 641         opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC);
 642         if (opt == NULL)
 643                 return NULL;
 644         memset(opt, 0, sizeof(*opt));
 645         opt->tot_len = sizeof(*opt) + hdrlen;
 646         opt->srcrt = (void*)(opt+1);
 647         opt->opt_nflen = hdrlen;
 648
 649         memcpy(opt->srcrt, hdr, sizeof(*hdr));
 650         irthdr = (struct rt0_hdr*)opt->srcrt;
 651         irthdr->reserved = 0;
 652         opt->srcrt->segments_left = n;
 653         for (i=0; i<n; i++)
 654                 memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16);
 655         return opt;
 656 }
 657
 658 EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);
 659
 660 /**********************************
 661   Hop-by-hop options.
 662  **********************************/
 663
 664 /* Router Alert as of RFC 2711 */
 665
 666 static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 667 {
 668         struct sk_buff *skb = *skbp;
 669         const unsigned char *nh = skb_network_header(skb);
 670
 671         if (nh[optoff + 1] == 2) {
 672                 IP6CB(skb)->ra = optoff;
 673                 return 1;
 674         }
 675         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 676                        nh[optoff + 1]);
 677         kfree_skb(skb);
 678         return 0;
 679 }
 680
 681 /* Jumbo payload */
 682
 683 static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
 684 {
 685         struct sk_buff *skb = *skbp;
 686         const unsigned char *nh = skb_network_header(skb);
 687         u32 pkt_len;
 688
 689         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 690                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 691                                nh[optoff+1]);
 692                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 693                                  IPSTATS_MIB_INHDRERRORS);
 694                 goto drop;
 695         }
 696
 697         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 698         if (pkt_len <= IPV6_MAXPLEN) {
 699                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 700                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 701                 return 0;
 702         }
 703         if (ipv6_hdr(skb)->payload_len) {
 704                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 705                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 706                 return 0;
 707         }
 708
 709         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 710                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS);
 711                 goto drop;
 712         }
 713
 714         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 715                 goto drop;
 716
 717         return 1;
 718
 719 drop:
 720         kfree_skb(skb);
 721         return 0;
 722 }
 723
 724 static struct tlvtype_proc tlvprochopopt_lst[] = {
 725         {
 726                 .type   = IPV6_TLV_ROUTERALERT,
 727                 .func   = ipv6_hop_ra,
 728         },
 729         {
 730                 .type   = IPV6_TLV_JUMBO,
 731                 .func   = ipv6_hop_jumbo,
 732         },
 733         { -1, }
 734 };
 735
 736 int ipv6_parse_hopopts(struct sk_buff **skbp)
 737 {
 738         struct sk_buff *skb = *skbp;
 739         struct inet6_skb_parm *opt = IP6CB(skb);
 740
 741         /*
 742          * skb_network_header(skb) is equal to skb->data, and
 743          * skb->h.raw - skb->nh.raw is always equal to
 744          * sizeof(struct ipv6hdr) by definition of
 745          * hop-by-hop options.
 746          */
 747         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 748             !pskb_may_pull(skb, sizeof(struct ipv6hdr) + ((skb->h.raw[1] + 1) << 3))) {
 749                 kfree_skb(skb);
 750                 return -1;
 751         }
 752
 753         opt->hop = sizeof(struct ipv6hdr);
 754         if (ip6_parse_tlv(tlvprochopopt_lst, skbp)) {
 755                 skb = *skbp;
 756                 skb->h.raw += (skb->h.raw[1]+1)<<3;
 757                 opt = IP6CB(skb);
 758                 opt->nhoff = sizeof(struct ipv6hdr);
 759                 return 1;
 760         }
 761         return -1;
 762 }
 763
 764 /*
 765  *      Creating outbound headers.
 766  *
 767  *      "build" functions work when skb is filled from head to tail (datagram)
 768  *      "push"  functions work when headers are added from tail to head (tcp)
 769  *
 770  *      In both cases we assume, that caller reserved enough room
 771  *      for headers.
 772  */
 773
 774 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 775                             struct ipv6_rt_hdr *opt,
 776                             struct in6_addr **addr_p)
 777 {
 778         struct rt0_hdr *phdr, *ihdr;
 779         int hops;
 780
 781         ihdr = (struct rt0_hdr *) opt;
 782
 783         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 784         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 785
 786         hops = ihdr->rt_hdr.hdrlen >> 1;
 787
 788         if (hops > 1)
 789                 memcpy(phdr->addr, ihdr->addr + 1,
 790                        (hops - 1) * sizeof(struct in6_addr));
 791
 792         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 793         *addr_p = ihdr->addr;
 794
 795         phdr->rt_hdr.nexthdr = *proto;
 796         *proto = NEXTHDR_ROUTING;
 797 }
 798
 799 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 800 {
 801         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 802
 803         memcpy(h, opt, ipv6_optlen(opt));
 804         h->nexthdr = *proto;
 805         *proto = type;
 806 }
 807
 808 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 809                           u8 *proto,
 810                           struct in6_addr **daddr)
 811 {
 812         if (opt->srcrt) {
 813                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 814                 /*
 815                  * IPV6_RTHDRDSTOPTS is ignored
 816                  * unless IPV6_RTHDR is set (RFC3542).
 817                  */
 818                 if (opt->dst0opt)
 819                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 820         }
 821         if (opt->hopopt)
 822                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 823 }
 824
 825 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 826
 827 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 828 {
 829         if (opt->dst1opt)
 830                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 831 }
 832
 833 struct ipv6_txoptions *
 834 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 835 {
 836         struct ipv6_txoptions *opt2;
 837
 838         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 839         if (opt2) {
 840                 long dif = (char*)opt2 - (char*)opt;
 841                 memcpy(opt2, opt, opt->tot_len);
 842                 if (opt2->hopopt)
 843                         *((char**)&opt2->hopopt) += dif;
 844                 if (opt2->dst0opt)
 845                         *((char**)&opt2->dst0opt) += dif;
 846                 if (opt2->dst1opt)
 847                         *((char**)&opt2->dst1opt) += dif;
 848                 if (opt2->srcrt)
 849                         *((char**)&opt2->srcrt) += dif;
 850         }
 851         return opt2;
 852 }
 853
 854 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 855
 856 static int ipv6_renew_option(void *ohdr,
 857                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 858                              int inherit,
 859                              struct ipv6_opt_hdr **hdr,
 860                              char **p)
 861 {
 862         if (inherit) {
 863                 if (ohdr) {
 864                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 865                         *hdr = (struct ipv6_opt_hdr *)*p;
 866                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 867                 }
 868         } else {
 869                 if (newopt) {
 870                         if (copy_from_user(*p, newopt, newoptlen))
 871                                 return -EFAULT;
 872                         *hdr = (struct ipv6_opt_hdr *)*p;
 873                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 874                                 return -EINVAL;
 875                         *p += CMSG_ALIGN(newoptlen);
 876                 }
 877         }
 878         return 0;
 879 }
 880
 881 struct ipv6_txoptions *
 882 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 883                    int newtype,
 884                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 885 {
 886         int tot_len = 0;
 887         char *p;
 888         struct ipv6_txoptions *opt2;
 889         int err;
 890
 891         if (opt) {
 892                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 893                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 894                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 895                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 896                 if (newtype != IPV6_RTHDR && opt->srcrt)
 897                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 898                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 899                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 900         }
 901
 902         if (newopt && newoptlen)
 903                 tot_len += CMSG_ALIGN(newoptlen);
 904
 905         if (!tot_len)
 906                 return NULL;
 907
 908         tot_len += sizeof(*opt2);
 909         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 910         if (!opt2)
 911                 return ERR_PTR(-ENOBUFS);
 912
 913         memset(opt2, 0, tot_len);
 914
 915         opt2->tot_len = tot_len;
 916         p = (char *)(opt2 + 1);
 917
 918         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 919                                 newtype != IPV6_HOPOPTS,
 920                                 &opt2->hopopt, &p);
 921         if (err)
 922                 goto out;
 923
 924         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 925                                 newtype != IPV6_RTHDRDSTOPTS,
 926                                 &opt2->dst0opt, &p);
 927         if (err)
 928                 goto out;
 929
 930         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 931                                 newtype != IPV6_RTHDR,
 932                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 933         if (err)
 934                 goto out;
 935
 936         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 937                                 newtype != IPV6_DSTOPTS,
 938                                 &opt2->dst1opt, &p);
 939         if (err)
 940                 goto out;
 941
 942         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 943                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 944                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 945         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 946
 947         return opt2;
 948 out:
 949         sock_kfree_s(sk, opt2, opt2->tot_len);
 950         return ERR_PTR(err);
 951 }
 952
 953 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 954                                           struct ipv6_txoptions *opt)
 955 {
 956         /*
 957          * ignore the dest before srcrt unless srcrt is being included.
 958          * --yoshfuji
 959          */
 960         if (opt && opt->dst0opt && !opt->srcrt) {
 961                 if (opt_space != opt) {
 962                         memcpy(opt_space, opt, sizeof(*opt_space));
 963                         opt = opt_space;
 964                 }
 965                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 966                 opt->dst0opt = NULL;
 967         }
 968
 969         return opt;
 970 }
 971