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 - 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
  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_network_header_len(skb);
 147         int len = (skb_transport_header(skb)[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_transport_header(skb)[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 = opt->dst1 = skb_network_header_len(skb);
 301 #ifdef CONFIG_IPV6_MIP6
 302         dstbuf = opt->dst1;
 303 #endif
 304
 305         dst = dst_clone(skb->dst);
 306         if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) {
 307                 dst_release(dst);
 308                 skb = *skbp;
 309                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 310                 opt = IP6CB(skb);
 311 #ifdef CONFIG_IPV6_MIP6
 312                 opt->nhoff = dstbuf;
 313 #else
 314                 opt->nhoff = opt->dst1;
 315 #endif
 316                 return 1;
 317         }
 318
 319         IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 320         dst_release(dst);
 321         return -1;
 322 }
 323
 324 static struct inet6_protocol destopt_protocol = {
 325         .handler        =       ipv6_destopt_rcv,
 326         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 327 };
 328
 329 void __init ipv6_destopt_init(void)
 330 {
 331         if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
 332                 printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
 333 }
 334
 335 /********************************
 336   NONE header. No data in packet.
 337  ********************************/
 338
 339 static int ipv6_nodata_rcv(struct sk_buff **skbp)
 340 {
 341         struct sk_buff *skb = *skbp;
 342
 343         kfree_skb(skb);
 344         return 0;
 345 }
 346
 347 static struct inet6_protocol nodata_protocol = {
 348         .handler        =       ipv6_nodata_rcv,
 349         .flags          =       INET6_PROTO_NOPOLICY,
 350 };
 351
 352 void __init ipv6_nodata_init(void)
 353 {
 354         if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
 355                 printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
 356 }
 357
 358 /********************************
 359   Routing header.
 360  ********************************/
 361
 362 static int ipv6_rthdr_rcv(struct sk_buff **skbp)
 363 {
 364         struct sk_buff *skb = *skbp;
 365         struct inet6_skb_parm *opt = IP6CB(skb);
 366         struct in6_addr *addr = NULL;
 367         struct in6_addr daddr;
 368         struct inet6_dev *idev;
 369         int n, i;
 370         struct ipv6_rt_hdr *hdr;
 371         struct rt0_hdr *rthdr;
 372         int accept_source_route = ipv6_devconf.accept_source_route;
 373
 374         if (accept_source_route < 0 ||
 375             ((idev = in6_dev_get(skb->dev)) == NULL)) {
 376                 kfree_skb(skb);
 377                 return -1;
 378         }
 379         if (idev->cnf.accept_source_route < 0) {
 380                 in6_dev_put(idev);
 381                 kfree_skb(skb);
 382                 return -1;
 383         }
 384
 385         if (accept_source_route > idev->cnf.accept_source_route)
 386                 accept_source_route = idev->cnf.accept_source_route;
 387
 388         in6_dev_put(idev);
 389
 390         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 391             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 392                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 393                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 394                                  IPSTATS_MIB_INHDRERRORS);
 395                 kfree_skb(skb);
 396                 return -1;
 397         }
 398
 399         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 400
 401         switch (hdr->type) {
 402 #ifdef CONFIG_IPV6_MIP6
 403         case IPV6_SRCRT_TYPE_2:
 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 = opt->srcrt = skb_network_header_len(skb);
 448                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 449                 opt->dst0 = opt->dst1;
 450                 opt->dst1 = 0;
 451                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 452                 return 1;
 453         }
 454
 455         switch (hdr->type) {
 456         case IPV6_SRCRT_TYPE_0:
 457                 if (hdr->hdrlen & 0x01) {
 458                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 459                                          IPSTATS_MIB_INHDRERRORS);
 460                         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 461                                           ((&hdr->hdrlen) -
 462                                            skb_network_header(skb)));
 463                         return -1;
 464                 }
 465                 break;
 466 #ifdef CONFIG_IPV6_MIP6
 467         case IPV6_SRCRT_TYPE_2:
 468                 /* Silently discard invalid RTH type 2 */
 469                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 470                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 471                                          IPSTATS_MIB_INHDRERRORS);
 472                         kfree_skb(skb);
 473                         return -1;
 474                 }
 475                 break;
 476 #endif
 477         }
 478
 479         /*
 480          *      This is the routing header forwarding algorithm from
 481          *      RFC 2460, page 16.
 482          */
 483
 484         n = hdr->hdrlen >> 1;
 485
 486         if (hdr->segments_left > n) {
 487                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 488                                  IPSTATS_MIB_INHDRERRORS);
 489                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 490                                   ((&hdr->segments_left) -
 491                                    skb_network_header(skb)));
 492                 return -1;
 493         }
 494
 495         /* We are about to mangle packet header. Be careful!
 496            Do not damage packets queued somewhere.
 497          */
 498         if (skb_cloned(skb)) {
 499                 struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC);
 500                 /* the copy is a forwarded packet */
 501                 if (skb2 == NULL) {
 502                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 503                                          IPSTATS_MIB_OUTDISCARDS);
 504                         kfree_skb(skb);
 505                         return -1;
 506                 }
 507                 kfree_skb(skb);
 508                 *skbp = skb = skb2;
 509                 opt = IP6CB(skb2);
 510                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb2);
 511         }
 512
 513         if (skb->ip_summed == CHECKSUM_COMPLETE)
 514                 skb->ip_summed = CHECKSUM_NONE;
 515
 516         i = n - --hdr->segments_left;
 517
 518         rthdr = (struct rt0_hdr *) hdr;
 519         addr = rthdr->addr;
 520         addr += i - 1;
 521
 522         switch (hdr->type) {
 523 #ifdef CONFIG_IPV6_MIP6
 524         case IPV6_SRCRT_TYPE_2:
 525                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 526                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 527                                      IPPROTO_ROUTING) < 0) {
 528                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 529                                          IPSTATS_MIB_INADDRERRORS);
 530                         kfree_skb(skb);
 531                         return -1;
 532                 }
 533                 if (!ipv6_chk_home_addr(addr)) {
 534                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 535                                          IPSTATS_MIB_INADDRERRORS);
 536                         kfree_skb(skb);
 537                         return -1;
 538                 }
 539                 break;
 540 #endif
 541         default:
 542                 break;
 543         }
 544
 545         if (ipv6_addr_is_multicast(addr)) {
 546                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 547                                  IPSTATS_MIB_INADDRERRORS);
 548                 kfree_skb(skb);
 549                 return -1;
 550         }
 551
 552         ipv6_addr_copy(&daddr, addr);
 553         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 554         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 555
 556         dst_release(xchg(&skb->dst, NULL));
 557         ip6_route_input(skb);
 558         if (skb->dst->error) {
 559                 skb_push(skb, skb->data - skb_network_header(skb));
 560                 dst_input(skb);
 561                 return -1;
 562         }
 563
 564         if (skb->dst->dev->flags&IFF_LOOPBACK) {
 565                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 566                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 567                                          IPSTATS_MIB_INHDRERRORS);
 568                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 569                                     0, skb->dev);
 570                         kfree_skb(skb);
 571                         return -1;
 572                 }
 573                 ipv6_hdr(skb)->hop_limit--;
 574                 goto looped_back;
 575         }
 576
 577         skb_push(skb, skb->data - skb_network_header(skb));
 578         dst_input(skb);
 579         return -1;
 580 }
 581
 582 static struct inet6_protocol rthdr_protocol = {
 583         .handler        =       ipv6_rthdr_rcv,
 584         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 585 };
 586
 587 void __init ipv6_rthdr_init(void)
 588 {
 589         if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
 590                 printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
 591 };
 592
 593 /*
 594    This function inverts received rthdr.
 595    NOTE: specs allow to make it automatically only if
 596    packet authenticated.
 597
 598    I will not discuss it here (though, I am really pissed off at
 599    this stupid requirement making rthdr idea useless)
 600
 601    Actually, it creates severe problems  for us.
 602    Embryonic requests has no associated sockets,
 603    so that user have no control over it and
 604    cannot not only to set reply options, but
 605    even to know, that someone wants to connect
 606    without success. :-(
 607
 608    For now we need to test the engine, so that I created
 609    temporary (or permanent) backdoor.
 610    If listening socket set IPV6_RTHDR to 2, then we invert header.
 611                                                    --ANK (980729)
 612  */
 613
 614 struct ipv6_txoptions *
 615 ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr)
 616 {
 617         /* Received rthdr:
 618
 619            [ H1 -> H2 -> ... H_prev ]  daddr=ME
 620
 621            Inverted result:
 622            [ H_prev -> ... -> H1 ] daddr =sender
 623
 624            Note, that IP output engine will rewrite this rthdr
 625            by rotating it left by one addr.
 626          */
 627
 628         int n, i;
 629         struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr;
 630         struct rt0_hdr *irthdr;
 631         struct ipv6_txoptions *opt;
 632         int hdrlen = ipv6_optlen(hdr);
 633
 634         if (hdr->segments_left ||
 635             hdr->type != IPV6_SRCRT_TYPE_0 ||
 636             hdr->hdrlen & 0x01)
 637                 return NULL;
 638
 639         n = hdr->hdrlen >> 1;
 640         opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC);
 641         if (opt == NULL)
 642                 return NULL;
 643         memset(opt, 0, sizeof(*opt));
 644         opt->tot_len = sizeof(*opt) + hdrlen;
 645         opt->srcrt = (void*)(opt+1);
 646         opt->opt_nflen = hdrlen;
 647
 648         memcpy(opt->srcrt, hdr, sizeof(*hdr));
 649         irthdr = (struct rt0_hdr*)opt->srcrt;
 650         irthdr->reserved = 0;
 651         opt->srcrt->segments_left = n;
 652         for (i=0; i<n; i++)
 653                 memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16);
 654         return opt;
 655 }
 656
 657 EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);
 658
 659 /**********************************
 660   Hop-by-hop options.
 661  **********************************/
 662
 663 /* Router Alert as of RFC 2711 */
 664
 665 static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 666 {
 667         struct sk_buff *skb = *skbp;
 668         const unsigned char *nh = skb_network_header(skb);
 669
 670         if (nh[optoff + 1] == 2) {
 671                 IP6CB(skb)->ra = optoff;
 672                 return 1;
 673         }
 674         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 675                        nh[optoff + 1]);
 676         kfree_skb(skb);
 677         return 0;
 678 }
 679
 680 /* Jumbo payload */
 681
 682 static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
 683 {
 684         struct sk_buff *skb = *skbp;
 685         const unsigned char *nh = skb_network_header(skb);
 686         u32 pkt_len;
 687
 688         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 689                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 690                                nh[optoff+1]);
 691                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 692                                  IPSTATS_MIB_INHDRERRORS);
 693                 goto drop;
 694         }
 695
 696         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 697         if (pkt_len <= IPV6_MAXPLEN) {
 698                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 699                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 700                 return 0;
 701         }
 702         if (ipv6_hdr(skb)->payload_len) {
 703                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 704                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 705                 return 0;
 706         }
 707
 708         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 709                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS);
 710                 goto drop;
 711         }
 712
 713         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 714                 goto drop;
 715
 716         return 1;
 717
 718 drop:
 719         kfree_skb(skb);
 720         return 0;
 721 }
 722
 723 static struct tlvtype_proc tlvprochopopt_lst[] = {
 724         {
 725                 .type   = IPV6_TLV_ROUTERALERT,
 726                 .func   = ipv6_hop_ra,
 727         },
 728         {
 729                 .type   = IPV6_TLV_JUMBO,
 730                 .func   = ipv6_hop_jumbo,
 731         },
 732         { -1, }
 733 };
 734
 735 int ipv6_parse_hopopts(struct sk_buff **skbp)
 736 {
 737         struct sk_buff *skb = *skbp;
 738         struct inet6_skb_parm *opt = IP6CB(skb);
 739
 740         /*
 741          * skb_network_header(skb) is equal to skb->data, and
 742          * skb_network_header_len(skb) is always equal to
 743          * sizeof(struct ipv6hdr) by definition of
 744          * hop-by-hop options.
 745          */
 746         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 747             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 748                                  ((skb_transport_header(skb)[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->transport_header += (skb_transport_header(skb)[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