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 #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: " NIP6_FMT "\n", NIP6(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(ip6_dst_idev(skb->dst),
 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);
 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(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS);
 306         dst_release(dst);
 307         return -1;
 308 }
 309
 310 static struct inet6_protocol destopt_protocol = {
 311         .handler        =       ipv6_destopt_rcv,
 312         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 313 };
 314
 315 void __init ipv6_destopt_init(void)
 316 {
 317         if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0)
 318                 printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n");
 319 }
 320
 321 /********************************
 322   NONE header. No data in packet.
 323  ********************************/
 324
 325 static int ipv6_nodata_rcv(struct sk_buff *skb)
 326 {
 327         kfree_skb(skb);
 328         return 0;
 329 }
 330
 331 static struct inet6_protocol nodata_protocol = {
 332         .handler        =       ipv6_nodata_rcv,
 333         .flags          =       INET6_PROTO_NOPOLICY,
 334 };
 335
 336 void __init ipv6_nodata_init(void)
 337 {
 338         if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0)
 339                 printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n");
 340 }
 341
 342 /********************************
 343   Routing header.
 344  ********************************/
 345
 346 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 347 {
 348         struct inet6_skb_parm *opt = IP6CB(skb);
 349         struct in6_addr *addr = NULL;
 350         struct in6_addr daddr;
 351         struct inet6_dev *idev;
 352         int n, i;
 353         struct ipv6_rt_hdr *hdr;
 354         struct rt0_hdr *rthdr;
 355         int accept_source_route = ipv6_devconf.accept_source_route;
 356
 357         idev = in6_dev_get(skb->dev);
 358         if (idev) {
 359                 if (accept_source_route > idev->cnf.accept_source_route)
 360                         accept_source_route = idev->cnf.accept_source_route;
 361                 in6_dev_put(idev);
 362         }
 363
 364         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 365             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 366                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 367                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 368                                  IPSTATS_MIB_INHDRERRORS);
 369                 kfree_skb(skb);
 370                 return -1;
 371         }
 372
 373         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 374
 375         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 376             skb->pkt_type != PACKET_HOST) {
 377                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 378                                  IPSTATS_MIB_INADDRERRORS);
 379                 kfree_skb(skb);
 380                 return -1;
 381         }
 382
 383 looped_back:
 384         if (hdr->segments_left == 0) {
 385                 switch (hdr->type) {
 386 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 387                 case IPV6_SRCRT_TYPE_2:
 388                         /* Silently discard type 2 header unless it was
 389                          * processed by own
 390                          */
 391                         if (!addr) {
 392                                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 393                                                  IPSTATS_MIB_INADDRERRORS);
 394                                 kfree_skb(skb);
 395                                 return -1;
 396                         }
 397                         break;
 398 #endif
 399                 default:
 400                         break;
 401                 }
 402
 403                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 404                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 405                 opt->dst0 = opt->dst1;
 406                 opt->dst1 = 0;
 407                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 408                 return 1;
 409         }
 410
 411         switch (hdr->type) {
 412 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 413         case IPV6_SRCRT_TYPE_2:
 414                 if (accept_source_route < 0)
 415                         goto unknown_rh;
 416                 /* Silently discard invalid RTH type 2 */
 417                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 418                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 419                                          IPSTATS_MIB_INHDRERRORS);
 420                         kfree_skb(skb);
 421                         return -1;
 422                 }
 423                 break;
 424 #endif
 425         default:
 426                 goto unknown_rh;
 427         }
 428
 429         /*
 430          *      This is the routing header forwarding algorithm from
 431          *      RFC 2460, page 16.
 432          */
 433
 434         n = hdr->hdrlen >> 1;
 435
 436         if (hdr->segments_left > n) {
 437                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 438                                  IPSTATS_MIB_INHDRERRORS);
 439                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 440                                   ((&hdr->segments_left) -
 441                                    skb_network_header(skb)));
 442                 return -1;
 443         }
 444
 445         /* We are about to mangle packet header. Be careful!
 446            Do not damage packets queued somewhere.
 447          */
 448         if (skb_cloned(skb)) {
 449                 /* the copy is a forwarded packet */
 450                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 451                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 452                                          IPSTATS_MIB_OUTDISCARDS);
 453                         kfree_skb(skb);
 454                         return -1;
 455                 }
 456                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 457         }
 458
 459         if (skb->ip_summed == CHECKSUM_COMPLETE)
 460                 skb->ip_summed = CHECKSUM_NONE;
 461
 462         i = n - --hdr->segments_left;
 463
 464         rthdr = (struct rt0_hdr *) hdr;
 465         addr = rthdr->addr;
 466         addr += i - 1;
 467
 468         switch (hdr->type) {
 469 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
 470         case IPV6_SRCRT_TYPE_2:
 471                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 472                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 473                                      IPPROTO_ROUTING) < 0) {
 474                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 475                                          IPSTATS_MIB_INADDRERRORS);
 476                         kfree_skb(skb);
 477                         return -1;
 478                 }
 479                 if (!ipv6_chk_home_addr(addr)) {
 480                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 481                                          IPSTATS_MIB_INADDRERRORS);
 482                         kfree_skb(skb);
 483                         return -1;
 484                 }
 485                 break;
 486 #endif
 487         default:
 488                 break;
 489         }
 490
 491         if (ipv6_addr_is_multicast(addr)) {
 492                 IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 493                                  IPSTATS_MIB_INADDRERRORS);
 494                 kfree_skb(skb);
 495                 return -1;
 496         }
 497
 498         ipv6_addr_copy(&daddr, addr);
 499         ipv6_addr_copy(addr, &ipv6_hdr(skb)->daddr);
 500         ipv6_addr_copy(&ipv6_hdr(skb)->daddr, &daddr);
 501
 502         dst_release(xchg(&skb->dst, NULL));
 503         ip6_route_input(skb);
 504         if (skb->dst->error) {
 505                 skb_push(skb, skb->data - skb_network_header(skb));
 506                 dst_input(skb);
 507                 return -1;
 508         }
 509
 510         if (skb->dst->dev->flags&IFF_LOOPBACK) {
 511                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 512                         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst),
 513                                          IPSTATS_MIB_INHDRERRORS);
 514                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 515                                     0, skb->dev);
 516                         kfree_skb(skb);
 517                         return -1;
 518                 }
 519                 ipv6_hdr(skb)->hop_limit--;
 520                 goto looped_back;
 521         }
 522
 523         skb_push(skb, skb->data - skb_network_header(skb));
 524         dst_input(skb);
 525         return -1;
 526
 527 unknown_rh:
 528         IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS);
 529         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 530                           (&hdr->type) - skb_network_header(skb));
 531         return -1;
 532 }
 533
 534 static struct inet6_protocol rthdr_protocol = {
 535         .handler        =       ipv6_rthdr_rcv,
 536         .flags          =       INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR,
 537 };
 538
 539 void __init ipv6_rthdr_init(void)
 540 {
 541         if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0)
 542                 printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n");
 543 };
 544
 545 /**********************************
 546   Hop-by-hop options.
 547  **********************************/
 548
 549 /*
 550  * Note: we cannot rely on skb->dst before we assign it in ip6_route_input().
 551  */
 552 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 553 {
 554         return skb->dst ? ip6_dst_idev(skb->dst) : __in6_dev_get(skb->dev);
 555 }
 556
 557 /* Router Alert as of RFC 2711 */
 558
 559 static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 560 {
 561         const unsigned char *nh = skb_network_header(skb);
 562
 563         if (nh[optoff + 1] == 2) {
 564                 IP6CB(skb)->ra = optoff;
 565                 return 1;
 566         }
 567         LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n",
 568                        nh[optoff + 1]);
 569         kfree_skb(skb);
 570         return 0;
 571 }
 572
 573 /* Jumbo payload */
 574
 575 static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 576 {
 577         const unsigned char *nh = skb_network_header(skb);
 578         u32 pkt_len;
 579
 580         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 581                 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 582                                nh[optoff+1]);
 583                 IP6_INC_STATS_BH(ipv6_skb_idev(skb),
 584                                  IPSTATS_MIB_INHDRERRORS);
 585                 goto drop;
 586         }
 587
 588         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 589         if (pkt_len <= IPV6_MAXPLEN) {
 590                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
 591                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 592                 return 0;
 593         }
 594         if (ipv6_hdr(skb)->payload_len) {
 595                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INHDRERRORS);
 596                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 597                 return 0;
 598         }
 599
 600         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 601                 IP6_INC_STATS_BH(ipv6_skb_idev(skb), IPSTATS_MIB_INTRUNCATEDPKTS);
 602                 goto drop;
 603         }
 604
 605         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 606                 goto drop;
 607
 608         return 1;
 609
 610 drop:
 611         kfree_skb(skb);
 612         return 0;
 613 }
 614
 615 static struct tlvtype_proc tlvprochopopt_lst[] = {
 616         {
 617                 .type   = IPV6_TLV_ROUTERALERT,
 618                 .func   = ipv6_hop_ra,
 619         },
 620         {
 621                 .type   = IPV6_TLV_JUMBO,
 622                 .func   = ipv6_hop_jumbo,
 623         },
 624         { -1, }
 625 };
 626
 627 int ipv6_parse_hopopts(struct sk_buff *skb)
 628 {
 629         struct inet6_skb_parm *opt = IP6CB(skb);
 630
 631         /*
 632          * skb_network_header(skb) is equal to skb->data, and
 633          * skb_network_header_len(skb) is always equal to
 634          * sizeof(struct ipv6hdr) by definition of
 635          * hop-by-hop options.
 636          */
 637         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
 638             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
 639                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 640                 kfree_skb(skb);
 641                 return -1;
 642         }
 643
 644         opt->hop = sizeof(struct ipv6hdr);
 645         if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
 646                 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3;
 647                 opt = IP6CB(skb);
 648                 opt->nhoff = sizeof(struct ipv6hdr);
 649                 return 1;
 650         }
 651         return -1;
 652 }
 653
 654 /*
 655  *      Creating outbound headers.
 656  *
 657  *      "build" functions work when skb is filled from head to tail (datagram)
 658  *      "push"  functions work when headers are added from tail to head (tcp)
 659  *
 660  *      In both cases we assume, that caller reserved enough room
 661  *      for headers.
 662  */
 663
 664 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
 665                             struct ipv6_rt_hdr *opt,
 666                             struct in6_addr **addr_p)
 667 {
 668         struct rt0_hdr *phdr, *ihdr;
 669         int hops;
 670
 671         ihdr = (struct rt0_hdr *) opt;
 672
 673         phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
 674         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
 675
 676         hops = ihdr->rt_hdr.hdrlen >> 1;
 677
 678         if (hops > 1)
 679                 memcpy(phdr->addr, ihdr->addr + 1,
 680                        (hops - 1) * sizeof(struct in6_addr));
 681
 682         ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p);
 683         *addr_p = ihdr->addr;
 684
 685         phdr->rt_hdr.nexthdr = *proto;
 686         *proto = NEXTHDR_ROUTING;
 687 }
 688
 689 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
 690 {
 691         struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt));
 692
 693         memcpy(h, opt, ipv6_optlen(opt));
 694         h->nexthdr = *proto;
 695         *proto = type;
 696 }
 697
 698 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
 699                           u8 *proto,
 700                           struct in6_addr **daddr)
 701 {
 702         if (opt->srcrt) {
 703                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
 704                 /*
 705                  * IPV6_RTHDRDSTOPTS is ignored
 706                  * unless IPV6_RTHDR is set (RFC3542).
 707                  */
 708                 if (opt->dst0opt)
 709                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
 710         }
 711         if (opt->hopopt)
 712                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 713 }
 714
 715 EXPORT_SYMBOL(ipv6_push_nfrag_opts);
 716
 717 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
 718 {
 719         if (opt->dst1opt)
 720                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
 721 }
 722
 723 struct ipv6_txoptions *
 724 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
 725 {
 726         struct ipv6_txoptions *opt2;
 727
 728         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
 729         if (opt2) {
 730                 long dif = (char*)opt2 - (char*)opt;
 731                 memcpy(opt2, opt, opt->tot_len);
 732                 if (opt2->hopopt)
 733                         *((char**)&opt2->hopopt) += dif;
 734                 if (opt2->dst0opt)
 735                         *((char**)&opt2->dst0opt) += dif;
 736                 if (opt2->dst1opt)
 737                         *((char**)&opt2->dst1opt) += dif;
 738                 if (opt2->srcrt)
 739                         *((char**)&opt2->srcrt) += dif;
 740         }
 741         return opt2;
 742 }
 743
 744 EXPORT_SYMBOL_GPL(ipv6_dup_options);
 745
 746 static int ipv6_renew_option(void *ohdr,
 747                              struct ipv6_opt_hdr __user *newopt, int newoptlen,
 748                              int inherit,
 749                              struct ipv6_opt_hdr **hdr,
 750                              char **p)
 751 {
 752         if (inherit) {
 753                 if (ohdr) {
 754                         memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
 755                         *hdr = (struct ipv6_opt_hdr *)*p;
 756                         *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
 757                 }
 758         } else {
 759                 if (newopt) {
 760                         if (copy_from_user(*p, newopt, newoptlen))
 761                                 return -EFAULT;
 762                         *hdr = (struct ipv6_opt_hdr *)*p;
 763                         if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
 764                                 return -EINVAL;
 765                         *p += CMSG_ALIGN(newoptlen);
 766                 }
 767         }
 768         return 0;
 769 }
 770
 771 struct ipv6_txoptions *
 772 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
 773                    int newtype,
 774                    struct ipv6_opt_hdr __user *newopt, int newoptlen)
 775 {
 776         int tot_len = 0;
 777         char *p;
 778         struct ipv6_txoptions *opt2;
 779         int err;
 780
 781         if (opt) {
 782                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
 783                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
 784                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
 785                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
 786                 if (newtype != IPV6_RTHDR && opt->srcrt)
 787                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
 788                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
 789                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
 790         }
 791
 792         if (newopt && newoptlen)
 793                 tot_len += CMSG_ALIGN(newoptlen);
 794
 795         if (!tot_len)
 796                 return NULL;
 797
 798         tot_len += sizeof(*opt2);
 799         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
 800         if (!opt2)
 801                 return ERR_PTR(-ENOBUFS);
 802
 803         memset(opt2, 0, tot_len);
 804
 805         opt2->tot_len = tot_len;
 806         p = (char *)(opt2 + 1);
 807
 808         err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen,
 809                                 newtype != IPV6_HOPOPTS,
 810                                 &opt2->hopopt, &p);
 811         if (err)
 812                 goto out;
 813
 814         err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen,
 815                                 newtype != IPV6_RTHDRDSTOPTS,
 816                                 &opt2->dst0opt, &p);
 817         if (err)
 818                 goto out;
 819
 820         err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen,
 821                                 newtype != IPV6_RTHDR,
 822                                 (struct ipv6_opt_hdr **)&opt2->srcrt, &p);
 823         if (err)
 824                 goto out;
 825
 826         err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen,
 827                                 newtype != IPV6_DSTOPTS,
 828                                 &opt2->dst1opt, &p);
 829         if (err)
 830                 goto out;
 831
 832         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
 833                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
 834                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
 835         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
 836
 837         return opt2;
 838 out:
 839         sock_kfree_s(sk, opt2, opt2->tot_len);
 840         return ERR_PTR(err);
 841 }
 842
 843 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
 844                                           struct ipv6_txoptions *opt)
 845 {
 846         /*
 847          * ignore the dest before srcrt unless srcrt is being included.
 848          * --yoshfuji
 849          */
 850         if (opt && opt->dst0opt && !opt->srcrt) {
 851                 if (opt_space != opt) {
 852                         memcpy(opt_space, opt, sizeof(*opt_space));
 853                         opt = opt_space;
 854                 }
 855                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
 856                 opt->dst0opt = NULL;
 857         }
 858
 859         return opt;
 860 }
 861