net/ipv6/exthdrs.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *      Extension Header handling for IPv6
   4  *      Linux INET6 implementation
   5  *
   6  *      Authors:
   7  *      Pedro Roque             <roque@di.fc.ul.pt>
   8  *      Andi Kleen              <ak@muc.de>
   9  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  10  */
  11
  12 /* Changes:
  13  *      yoshfuji                : ensure not to overrun while parsing
  14  *                                tlv options.
  15  *      Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs().
  16  *      YOSHIFUJI Hideaki @USAGI  Register inbound extension header
  17  *                                handlers as inet6_protocol{}.
  18  */
  19
  20 #include <linux/errno.h>
  21 #include <linux/types.h>
  22 #include <linux/socket.h>
  23 #include <linux/sockios.h>
  24 #include <linux/net.h>
  25 #include <linux/netdevice.h>
  26 #include <linux/in6.h>
  27 #include <linux/icmpv6.h>
  28 #include <linux/slab.h>
  29 #include <linux/export.h>
  30
  31 #include <net/dst.h>
  32 #include <net/sock.h>
  33 #include <net/snmp.h>
  34
  35 #include <net/ipv6.h>
  36 #include <net/protocol.h>
  37 #include <net/transp_v6.h>
  38 #include <net/rawv6.h>
  39 #include <net/ndisc.h>
  40 #include <net/ip6_route.h>
  41 #include <net/addrconf.h>
  42 #include <net/calipso.h>
  43 #if IS_ENABLED(CONFIG_IPV6_MIP6)
  44 #include <net/xfrm.h>
  45 #endif
  46 #include <linux/seg6.h>
  47 #include <net/seg6.h>
  48 #ifdef CONFIG_IPV6_SEG6_HMAC
  49 #include <net/seg6_hmac.h>
  50 #endif
  51 #include <net/rpl.h>
  52
  53 #include <linux/uaccess.h>
  54
  55 /*
  56  *      Parsing tlv encoded headers.
  57  *
  58  *      Parsing function "func" returns true, if parsing succeed
  59  *      and false, if it failed.
  60  *      It MUST NOT touch skb->h.
  61  */
  62
  63 struct tlvtype_proc {
  64         int     type;
  65         bool    (*func)(struct sk_buff *skb, int offset);
  66 };
  67
  68 /*********************
  69   Generic functions
  70  *********************/
  71
  72 /* An unknown option is detected, decide what to do */
  73
  74 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
  75                                bool disallow_unknowns)
  76 {
  77         if (disallow_unknowns) {
  78                 /* If unknown TLVs are disallowed by configuration
  79                  * then always silently drop packet. Note this also
  80                  * means no ICMP parameter problem is sent which
  81                  * could be a good property to mitigate a reflection DOS
  82                  * attack.
  83                  */
  84
  85                 goto drop;
  86         }
  87
  88         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
  89         case 0: /* ignore */
  90                 return true;
  91
  92         case 1: /* drop packet */
  93                 break;
  94
  95         case 3: /* Send ICMP if not a multicast address and drop packet */
  96                 /* Actually, it is redundant check. icmp_send
  97                    will recheck in any case.
  98                  */
  99                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
 100                         break;
 101                 fallthrough;
 102         case 2: /* send ICMP PARM PROB regardless and drop packet */
 103                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
 104                 return false;
 105         }
 106
 107 drop:
 108         kfree_skb(skb);
 109         return false;
 110 }
 111
 112 /* Parse tlv encoded option header (hop-by-hop or destination) */
 113
 114 static bool ip6_parse_tlv(const struct tlvtype_proc *procs,
 115                           struct sk_buff *skb,
 116                           int max_count)
 117 {
 118         int len = (skb_transport_header(skb)[1] + 1) << 3;
 119         const unsigned char *nh = skb_network_header(skb);
 120         int off = skb_network_header_len(skb);
 121         const struct tlvtype_proc *curr;
 122         bool disallow_unknowns = false;
 123         int tlv_count = 0;
 124         int padlen = 0;
 125
 126         if (unlikely(max_count < 0)) {
 127                 disallow_unknowns = true;
 128                 max_count = -max_count;
 129         }
 130
 131         if (skb_transport_offset(skb) + len > skb_headlen(skb))
 132                 goto bad;
 133
 134         off += 2;
 135         len -= 2;
 136
 137         while (len > 0) {
 138                 int optlen, i;
 139
 140                 if (nh[off] == IPV6_TLV_PAD1) {
 141                         padlen++;
 142                         if (padlen > 7)
 143                                 goto bad;
 144                         off++;
 145                         len--;
 146                         continue;
 147                 }
 148                 if (len < 2)
 149                         goto bad;
 150                 optlen = nh[off + 1] + 2;
 151                 if (optlen > len)
 152                         goto bad;
 153
 154                 if (nh[off] == IPV6_TLV_PADN) {
 155                         /* RFC 2460 states that the purpose of PadN is
 156                          * to align the containing header to multiples
 157                          * of 8. 7 is therefore the highest valid value.
 158                          * See also RFC 4942, Section 2.1.9.5.
 159                          */
 160                         padlen += optlen;
 161                         if (padlen > 7)
 162                                 goto bad;
 163                         /* RFC 4942 recommends receiving hosts to
 164                          * actively check PadN payload to contain
 165                          * only zeroes.
 166                          */
 167                         for (i = 2; i < optlen; i++) {
 168                                 if (nh[off + i] != 0)
 169                                         goto bad;
 170                         }
 171                 } else {
 172                         tlv_count++;
 173                         if (tlv_count > max_count)
 174                                 goto bad;
 175
 176                         for (curr = procs; curr->type >= 0; curr++) {
 177                                 if (curr->type == nh[off]) {
 178                                         /* type specific length/alignment
 179                                            checks will be performed in the
 180                                            func(). */
 181                                         if (curr->func(skb, off) == false)
 182                                                 return false;
 183                                         break;
 184                                 }
 185                         }
 186                         if (curr->type < 0 &&
 187                             !ip6_tlvopt_unknown(skb, off, disallow_unknowns))
 188                                 return false;
 189
 190                         padlen = 0;
 191                 }
 192                 off += optlen;
 193                 len -= optlen;
 194         }
 195
 196         if (len == 0)
 197                 return true;
 198 bad:
 199         kfree_skb(skb);
 200         return false;
 201 }
 202
 203 /*****************************
 204   Destination options header.
 205  *****************************/
 206
 207 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 208 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
 209 {
 210         struct ipv6_destopt_hao *hao;
 211         struct inet6_skb_parm *opt = IP6CB(skb);
 212         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 213         int ret;
 214
 215         if (opt->dsthao) {
 216                 net_dbg_ratelimited("hao duplicated\n");
 217                 goto discard;
 218         }
 219         opt->dsthao = opt->dst1;
 220         opt->dst1 = 0;
 221
 222         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 223
 224         if (hao->length != 16) {
 225                 net_dbg_ratelimited("hao invalid option length = %d\n",
 226                                     hao->length);
 227                 goto discard;
 228         }
 229
 230         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 231                 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
 232                                     &hao->addr);
 233                 goto discard;
 234         }
 235
 236         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 237                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 238         if (unlikely(ret < 0))
 239                 goto discard;
 240
 241         if (skb_cloned(skb)) {
 242                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 243                         goto discard;
 244
 245                 /* update all variable using below by copied skbuff */
 246                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
 247                                                   optoff);
 248                 ipv6h = ipv6_hdr(skb);
 249         }
 250
 251         if (skb->ip_summed == CHECKSUM_COMPLETE)
 252                 skb->ip_summed = CHECKSUM_NONE;
 253
 254         swap(ipv6h->saddr, hao->addr);
 255
 256         if (skb->tstamp == 0)
 257                 __net_timestamp(skb);
 258
 259         return true;
 260
 261  discard:
 262         kfree_skb(skb);
 263         return false;
 264 }
 265 #endif
 266
 267 static const struct tlvtype_proc tlvprocdestopt_lst[] = {
 268 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 269         {
 270                 .type   = IPV6_TLV_HAO,
 271                 .func   = ipv6_dest_hao,
 272         },
 273 #endif
 274         {-1,                    NULL}
 275 };
 276
 277 static int ipv6_destopt_rcv(struct sk_buff *skb)
 278 {
 279         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 280         struct inet6_skb_parm *opt = IP6CB(skb);
 281 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 282         __u16 dstbuf;
 283 #endif
 284         struct dst_entry *dst = skb_dst(skb);
 285         struct net *net = dev_net(skb->dev);
 286         int extlen;
 287
 288         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 289             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 290                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 291                 __IP6_INC_STATS(dev_net(dst->dev), idev,
 292                                 IPSTATS_MIB_INHDRERRORS);
 293 fail_and_free:
 294                 kfree_skb(skb);
 295                 return -1;
 296         }
 297
 298         extlen = (skb_transport_header(skb)[1] + 1) << 3;
 299         if (extlen > net->ipv6.sysctl.max_dst_opts_len)
 300                 goto fail_and_free;
 301
 302         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 303 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 304         dstbuf = opt->dst1;
 305 #endif
 306
 307         if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
 308                           net->ipv6.sysctl.max_dst_opts_cnt)) {
 309                 skb->transport_header += extlen;
 310                 opt = IP6CB(skb);
 311 #if IS_ENABLED(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(net, idev, IPSTATS_MIB_INHDRERRORS);
 320         return -1;
 321 }
 322
 323 static void seg6_update_csum(struct sk_buff *skb)
 324 {
 325         struct ipv6_sr_hdr *hdr;
 326         struct in6_addr *addr;
 327         __be32 from, to;
 328
 329         /* srh is at transport offset and seg_left is already decremented
 330          * but daddr is not yet updated with next segment
 331          */
 332
 333         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 334         addr = hdr->segments + hdr->segments_left;
 335
 336         hdr->segments_left++;
 337         from = *(__be32 *)hdr;
 338
 339         hdr->segments_left--;
 340         to = *(__be32 *)hdr;
 341
 342         /* update skb csum with diff resulting from seg_left decrement */
 343
 344         update_csum_diff4(skb, from, to);
 345
 346         /* compute csum diff between current and next segment and update */
 347
 348         update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
 349                            (__be32 *)addr);
 350 }
 351
 352 static int ipv6_srh_rcv(struct sk_buff *skb)
 353 {
 354         struct inet6_skb_parm *opt = IP6CB(skb);
 355         struct net *net = dev_net(skb->dev);
 356         struct ipv6_sr_hdr *hdr;
 357         struct inet6_dev *idev;
 358         struct in6_addr *addr;
 359         int accept_seg6;
 360
 361         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 362
 363         idev = __in6_dev_get(skb->dev);
 364
 365         accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
 366         if (accept_seg6 > idev->cnf.seg6_enabled)
 367                 accept_seg6 = idev->cnf.seg6_enabled;
 368
 369         if (!accept_seg6) {
 370                 kfree_skb(skb);
 371                 return -1;
 372         }
 373
 374 #ifdef CONFIG_IPV6_SEG6_HMAC
 375         if (!seg6_hmac_validate_skb(skb)) {
 376                 kfree_skb(skb);
 377                 return -1;
 378         }
 379 #endif
 380
 381 looped_back:
 382         if (hdr->segments_left == 0) {
 383                 if (hdr->nexthdr == NEXTHDR_IPV6) {
 384                         int offset = (hdr->hdrlen + 1) << 3;
 385
 386                         skb_postpull_rcsum(skb, skb_network_header(skb),
 387                                            skb_network_header_len(skb));
 388
 389                         if (!pskb_pull(skb, offset)) {
 390                                 kfree_skb(skb);
 391                                 return -1;
 392                         }
 393                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 394                                            offset);
 395
 396                         skb_reset_network_header(skb);
 397                         skb_reset_transport_header(skb);
 398                         skb->encapsulation = 0;
 399
 400                         __skb_tunnel_rx(skb, skb->dev, net);
 401
 402                         netif_rx(skb);
 403                         return -1;
 404                 }
 405
 406                 opt->srcrt = skb_network_header_len(skb);
 407                 opt->lastopt = opt->srcrt;
 408                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 409                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 410
 411                 return 1;
 412         }
 413
 414         if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
 415                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 416                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 417                                   ((&hdr->segments_left) -
 418                                    skb_network_header(skb)));
 419                 return -1;
 420         }
 421
 422         if (skb_cloned(skb)) {
 423                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 424                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 425                                         IPSTATS_MIB_OUTDISCARDS);
 426                         kfree_skb(skb);
 427                         return -1;
 428                 }
 429         }
 430
 431         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 432
 433         hdr->segments_left--;
 434         addr = hdr->segments + hdr->segments_left;
 435
 436         skb_push(skb, sizeof(struct ipv6hdr));
 437
 438         if (skb->ip_summed == CHECKSUM_COMPLETE)
 439                 seg6_update_csum(skb);
 440
 441         ipv6_hdr(skb)->daddr = *addr;
 442
 443         skb_dst_drop(skb);
 444
 445         ip6_route_input(skb);
 446
 447         if (skb_dst(skb)->error) {
 448                 dst_input(skb);
 449                 return -1;
 450         }
 451
 452         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 453                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 454                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 455                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 456                                     ICMPV6_EXC_HOPLIMIT, 0);
 457                         kfree_skb(skb);
 458                         return -1;
 459                 }
 460                 ipv6_hdr(skb)->hop_limit--;
 461
 462                 skb_pull(skb, sizeof(struct ipv6hdr));
 463                 goto looped_back;
 464         }
 465
 466         dst_input(skb);
 467
 468         return -1;
 469 }
 470
 471 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 472 {
 473         struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
 474         struct inet6_skb_parm *opt = IP6CB(skb);
 475         struct net *net = dev_net(skb->dev);
 476         struct inet6_dev *idev;
 477         struct ipv6hdr *oldhdr;
 478         struct in6_addr addr;
 479         unsigned char *buf;
 480         int accept_rpl_seg;
 481         int i, err;
 482         u64 n = 0;
 483         u32 r;
 484
 485         idev = __in6_dev_get(skb->dev);
 486
 487         accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
 488         if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
 489                 accept_rpl_seg = idev->cnf.rpl_seg_enabled;
 490
 491         if (!accept_rpl_seg) {
 492                 kfree_skb(skb);
 493                 return -1;
 494         }
 495
 496 looped_back:
 497         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 498
 499         if (hdr->segments_left == 0) {
 500                 if (hdr->nexthdr == NEXTHDR_IPV6) {
 501                         int offset = (hdr->hdrlen + 1) << 3;
 502
 503                         skb_postpull_rcsum(skb, skb_network_header(skb),
 504                                            skb_network_header_len(skb));
 505
 506                         if (!pskb_pull(skb, offset)) {
 507                                 kfree_skb(skb);
 508                                 return -1;
 509                         }
 510                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 511                                            offset);
 512
 513                         skb_reset_network_header(skb);
 514                         skb_reset_transport_header(skb);
 515                         skb->encapsulation = 0;
 516
 517                         __skb_tunnel_rx(skb, skb->dev, net);
 518
 519                         netif_rx(skb);
 520                         return -1;
 521                 }
 522
 523                 opt->srcrt = skb_network_header_len(skb);
 524                 opt->lastopt = opt->srcrt;
 525                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 526                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 527
 528                 return 1;
 529         }
 530
 531         if (!pskb_may_pull(skb, sizeof(*hdr))) {
 532                 kfree_skb(skb);
 533                 return -1;
 534         }
 535
 536         n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
 537         r = do_div(n, (16 - hdr->cmpri));
 538         /* checks if calculation was without remainder and n fits into
 539          * unsigned char which is segments_left field. Should not be
 540          * higher than that.
 541          */
 542         if (r || (n + 1) > 255) {
 543                 kfree_skb(skb);
 544                 return -1;
 545         }
 546
 547         if (hdr->segments_left > n + 1) {
 548                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 549                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 550                                   ((&hdr->segments_left) -
 551                                    skb_network_header(skb)));
 552                 return -1;
 553         }
 554
 555         if (skb_cloned(skb)) {
 556                 if (pskb_expand_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE, 0,
 557                                      GFP_ATOMIC)) {
 558                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 559                                         IPSTATS_MIB_OUTDISCARDS);
 560                         kfree_skb(skb);
 561                         return -1;
 562                 }
 563         } else {
 564                 err = skb_cow_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE);
 565                 if (unlikely(err)) {
 566                         kfree_skb(skb);
 567                         return -1;
 568                 }
 569         }
 570
 571         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 572
 573         if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
 574                                                   hdr->cmpre))) {
 575                 kfree_skb(skb);
 576                 return -1;
 577         }
 578
 579         hdr->segments_left--;
 580         i = n - hdr->segments_left;
 581
 582         buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
 583         if (unlikely(!buf)) {
 584                 kfree_skb(skb);
 585                 return -1;
 586         }
 587
 588         ohdr = (struct ipv6_rpl_sr_hdr *)buf;
 589         ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 590         chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 591
 592         if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
 593             (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
 594                 kfree_skb(skb);
 595                 kfree(buf);
 596                 return -1;
 597         }
 598
 599         err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
 600         if (err) {
 601                 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
 602                 kfree_skb(skb);
 603                 kfree(buf);
 604                 return -1;
 605         }
 606
 607         addr = ipv6_hdr(skb)->daddr;
 608         ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
 609         ohdr->rpl_segaddr[i] = addr;
 610
 611         ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
 612
 613         oldhdr = ipv6_hdr(skb);
 614
 615         skb_pull(skb, ((hdr->hdrlen + 1) << 3));
 616         skb_postpull_rcsum(skb, oldhdr,
 617                            sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
 618         skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
 619         skb_reset_network_header(skb);
 620         skb_mac_header_rebuild(skb);
 621         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 622
 623         memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
 624         memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
 625
 626         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 627         skb_postpush_rcsum(skb, ipv6_hdr(skb),
 628                            sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
 629
 630         kfree(buf);
 631
 632         skb_dst_drop(skb);
 633
 634         ip6_route_input(skb);
 635
 636         if (skb_dst(skb)->error) {
 637                 dst_input(skb);
 638                 return -1;
 639         }
 640
 641         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 642                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 643                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 644                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 645                                     ICMPV6_EXC_HOPLIMIT, 0);
 646                         kfree_skb(skb);
 647                         return -1;
 648                 }
 649                 ipv6_hdr(skb)->hop_limit--;
 650
 651                 skb_pull(skb, sizeof(struct ipv6hdr));
 652                 goto looped_back;
 653         }
 654
 655         dst_input(skb);
 656
 657         return -1;
 658 }
 659
 660 /********************************
 661   Routing header.
 662  ********************************/
 663
 664 /* called with rcu_read_lock() */
 665 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 666 {
 667         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 668         struct inet6_skb_parm *opt = IP6CB(skb);
 669         struct in6_addr *addr = NULL;
 670         struct in6_addr daddr;
 671         int n, i;
 672         struct ipv6_rt_hdr *hdr;
 673         struct rt0_hdr *rthdr;
 674         struct net *net = dev_net(skb->dev);
 675         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 676
 677         idev = __in6_dev_get(skb->dev);
 678         if (idev && accept_source_route > idev->cnf.accept_source_route)
 679                 accept_source_route = idev->cnf.accept_source_route;
 680
 681         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 682             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 683                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 684                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 685                 kfree_skb(skb);
 686                 return -1;
 687         }
 688
 689         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 690
 691         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 692             skb->pkt_type != PACKET_HOST) {
 693                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 694                 kfree_skb(skb);
 695                 return -1;
 696         }
 697
 698         switch (hdr->type) {
 699         case IPV6_SRCRT_TYPE_4:
 700                 /* segment routing */
 701                 return ipv6_srh_rcv(skb);
 702         case IPV6_SRCRT_TYPE_3:
 703                 /* rpl segment routing */
 704                 return ipv6_rpl_srh_rcv(skb);
 705         default:
 706                 break;
 707         }
 708
 709 looped_back:
 710         if (hdr->segments_left == 0) {
 711                 switch (hdr->type) {
 712 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 713                 case IPV6_SRCRT_TYPE_2:
 714                         /* Silently discard type 2 header unless it was
 715                          * processed by own
 716                          */
 717                         if (!addr) {
 718                                 __IP6_INC_STATS(net, idev,
 719                                                 IPSTATS_MIB_INADDRERRORS);
 720                                 kfree_skb(skb);
 721                                 return -1;
 722                         }
 723                         break;
 724 #endif
 725                 default:
 726                         break;
 727                 }
 728
 729                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 730                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 731                 opt->dst0 = opt->dst1;
 732                 opt->dst1 = 0;
 733                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 734                 return 1;
 735         }
 736
 737         switch (hdr->type) {
 738 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 739         case IPV6_SRCRT_TYPE_2:
 740                 if (accept_source_route < 0)
 741                         goto unknown_rh;
 742                 /* Silently discard invalid RTH type 2 */
 743                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 744                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 745                         kfree_skb(skb);
 746                         return -1;
 747                 }
 748                 break;
 749 #endif
 750         default:
 751                 goto unknown_rh;
 752         }
 753
 754         /*
 755          *      This is the routing header forwarding algorithm from
 756          *      RFC 2460, page 16.
 757          */
 758
 759         n = hdr->hdrlen >> 1;
 760
 761         if (hdr->segments_left > n) {
 762                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 763                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 764                                   ((&hdr->segments_left) -
 765                                    skb_network_header(skb)));
 766                 return -1;
 767         }
 768
 769         /* We are about to mangle packet header. Be careful!
 770            Do not damage packets queued somewhere.
 771          */
 772         if (skb_cloned(skb)) {
 773                 /* the copy is a forwarded packet */
 774                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 775                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 776                                         IPSTATS_MIB_OUTDISCARDS);
 777                         kfree_skb(skb);
 778                         return -1;
 779                 }
 780                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 781         }
 782
 783         if (skb->ip_summed == CHECKSUM_COMPLETE)
 784                 skb->ip_summed = CHECKSUM_NONE;
 785
 786         i = n - --hdr->segments_left;
 787
 788         rthdr = (struct rt0_hdr *) hdr;
 789         addr = rthdr->addr;
 790         addr += i - 1;
 791
 792         switch (hdr->type) {
 793 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 794         case IPV6_SRCRT_TYPE_2:
 795                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 796                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 797                                      IPPROTO_ROUTING) < 0) {
 798                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 799                         kfree_skb(skb);
 800                         return -1;
 801                 }
 802                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 803                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 804                         kfree_skb(skb);
 805                         return -1;
 806                 }
 807                 break;
 808 #endif
 809         default:
 810                 break;
 811         }
 812
 813         if (ipv6_addr_is_multicast(addr)) {
 814                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 815                 kfree_skb(skb);
 816                 return -1;
 817         }
 818
 819         daddr = *addr;
 820         *addr = ipv6_hdr(skb)->daddr;
 821         ipv6_hdr(skb)->daddr = daddr;
 822
 823         skb_dst_drop(skb);
 824         ip6_route_input(skb);
 825         if (skb_dst(skb)->error) {
 826                 skb_push(skb, skb->data - skb_network_header(skb));
 827                 dst_input(skb);
 828                 return -1;
 829         }
 830
 831         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 832                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 833                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 834                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 835                                     0);
 836                         kfree_skb(skb);
 837                         return -1;
 838                 }
 839                 ipv6_hdr(skb)->hop_limit--;
 840                 goto looped_back;
 841         }
 842
 843         skb_push(skb, skb->data - skb_network_header(skb));
 844         dst_input(skb);
 845         return -1;
 846
 847 unknown_rh:
 848         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 849         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 850                           (&hdr->type) - skb_network_header(skb));
 851         return -1;
 852 }
 853
 854 static const struct inet6_protocol rthdr_protocol = {
 855         .handler        =       ipv6_rthdr_rcv,
 856         .flags          =       INET6_PROTO_NOPOLICY,
 857 };
 858
 859 static const struct inet6_protocol destopt_protocol = {
 860         .handler        =       ipv6_destopt_rcv,
 861         .flags          =       INET6_PROTO_NOPOLICY,
 862 };
 863
 864 static const struct inet6_protocol nodata_protocol = {
 865         .handler        =       dst_discard,
 866         .flags          =       INET6_PROTO_NOPOLICY,
 867 };
 868
 869 int __init ipv6_exthdrs_init(void)
 870 {
 871         int ret;
 872
 873         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 874         if (ret)
 875                 goto out;
 876
 877         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 878         if (ret)
 879                 goto out_rthdr;
 880
 881         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 882         if (ret)
 883                 goto out_destopt;
 884
 885 out:
 886         return ret;
 887 out_destopt:
 888         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 889 out_rthdr:
 890         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 891         goto out;
 892 };
 893
 894 void ipv6_exthdrs_exit(void)
 895 {
 896         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 897         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 898         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 899 }
 900
 901 /**********************************
 902   Hop-by-hop options.
 903  **********************************/
 904
 905 /*
 906  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 907  */
 908 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 909 {
 910         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 911 }
 912
 913 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 914 {
 915         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 916 }
 917
 918 /* Router Alert as of RFC 2711 */
 919
 920 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 921 {
 922         const unsigned char *nh = skb_network_header(skb);
 923
 924         if (nh[optoff + 1] == 2) {
 925                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 926                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 927                 return true;
 928         }
 929         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 930                             nh[optoff + 1]);
 931         kfree_skb(skb);
 932         return false;
 933 }
 934
 935 /* Jumbo payload */
 936
 937 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 938 {
 939         const unsigned char *nh = skb_network_header(skb);
 940         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 941         struct net *net = ipv6_skb_net(skb);
 942         u32 pkt_len;
 943
 944         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 945                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 946                                     nh[optoff+1]);
 947                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 948                 goto drop;
 949         }
 950
 951         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 952         if (pkt_len <= IPV6_MAXPLEN) {
 953                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 954                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 955                 return false;
 956         }
 957         if (ipv6_hdr(skb)->payload_len) {
 958                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 959                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 960                 return false;
 961         }
 962
 963         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 964                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 965                 goto drop;
 966         }
 967
 968         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 969                 goto drop;
 970
 971         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
 972         return true;
 973
 974 drop:
 975         kfree_skb(skb);
 976         return false;
 977 }
 978
 979 /* CALIPSO RFC 5570 */
 980
 981 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
 982 {
 983         const unsigned char *nh = skb_network_header(skb);
 984
 985         if (nh[optoff + 1] < 8)
 986                 goto drop;
 987
 988         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
 989                 goto drop;
 990
 991         if (!calipso_validate(skb, nh + optoff))
 992                 goto drop;
 993
 994         return true;
 995
 996 drop:
 997         kfree_skb(skb);
 998         return false;
 999 }
1000
1001 static const struct tlvtype_proc tlvprochopopt_lst[] = {
1002         {
1003                 .type   = IPV6_TLV_ROUTERALERT,
1004                 .func   = ipv6_hop_ra,
1005         },
1006         {
1007                 .type   = IPV6_TLV_JUMBO,
1008                 .func   = ipv6_hop_jumbo,
1009         },
1010         {
1011                 .type   = IPV6_TLV_CALIPSO,
1012                 .func   = ipv6_hop_calipso,
1013         },
1014         { -1, }
1015 };
1016
1017 int ipv6_parse_hopopts(struct sk_buff *skb)
1018 {
1019         struct inet6_skb_parm *opt = IP6CB(skb);
1020         struct net *net = dev_net(skb->dev);
1021         int extlen;
1022
1023         /*
1024          * skb_network_header(skb) is equal to skb->data, and
1025          * skb_network_header_len(skb) is always equal to
1026          * sizeof(struct ipv6hdr) by definition of
1027          * hop-by-hop options.
1028          */
1029         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1030             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1031                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1032 fail_and_free:
1033                 kfree_skb(skb);
1034                 return -1;
1035         }
1036
1037         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1038         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1039                 goto fail_and_free;
1040
1041         opt->flags |= IP6SKB_HOPBYHOP;
1042         if (ip6_parse_tlv(tlvprochopopt_lst, skb,
1043                           net->ipv6.sysctl.max_hbh_opts_cnt)) {
1044                 skb->transport_header += extlen;
1045                 opt = IP6CB(skb);
1046                 opt->nhoff = sizeof(struct ipv6hdr);
1047                 return 1;
1048         }
1049         return -1;
1050 }
1051
1052 /*
1053  *      Creating outbound headers.
1054  *
1055  *      "build" functions work when skb is filled from head to tail (datagram)
1056  *      "push"  functions work when headers are added from tail to head (tcp)
1057  *
1058  *      In both cases we assume, that caller reserved enough room
1059  *      for headers.
1060  */
1061
1062 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1063                              struct ipv6_rt_hdr *opt,
1064                              struct in6_addr **addr_p, struct in6_addr *saddr)
1065 {
1066         struct rt0_hdr *phdr, *ihdr;
1067         int hops;
1068
1069         ihdr = (struct rt0_hdr *) opt;
1070
1071         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1072         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1073
1074         hops = ihdr->rt_hdr.hdrlen >> 1;
1075
1076         if (hops > 1)
1077                 memcpy(phdr->addr, ihdr->addr + 1,
1078                        (hops - 1) * sizeof(struct in6_addr));
1079
1080         phdr->addr[hops - 1] = **addr_p;
1081         *addr_p = ihdr->addr;
1082
1083         phdr->rt_hdr.nexthdr = *proto;
1084         *proto = NEXTHDR_ROUTING;
1085 }
1086
1087 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1088                              struct ipv6_rt_hdr *opt,
1089                              struct in6_addr **addr_p, struct in6_addr *saddr)
1090 {
1091         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1092         int plen, hops;
1093
1094         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1095         plen = (sr_ihdr->hdrlen + 1) << 3;
1096
1097         sr_phdr = skb_push(skb, plen);
1098         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1099
1100         hops = sr_ihdr->first_segment + 1;
1101         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1102                (hops - 1) * sizeof(struct in6_addr));
1103
1104         sr_phdr->segments[0] = **addr_p;
1105         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1106
1107         if (sr_ihdr->hdrlen > hops * 2) {
1108                 int tlvs_offset, tlvs_length;
1109
1110                 tlvs_offset = (1 + hops * 2) << 3;
1111                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1112                 memcpy((char *)sr_phdr + tlvs_offset,
1113                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1114         }
1115
1116 #ifdef CONFIG_IPV6_SEG6_HMAC
1117         if (sr_has_hmac(sr_phdr)) {
1118                 struct net *net = NULL;
1119
1120                 if (skb->dev)
1121                         net = dev_net(skb->dev);
1122                 else if (skb->sk)
1123                         net = sock_net(skb->sk);
1124
1125                 WARN_ON(!net);
1126
1127                 if (net)
1128                         seg6_push_hmac(net, saddr, sr_phdr);
1129         }
1130 #endif
1131
1132         sr_phdr->nexthdr = *proto;
1133         *proto = NEXTHDR_ROUTING;
1134 }
1135
1136 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1137                             struct ipv6_rt_hdr *opt,
1138                             struct in6_addr **addr_p, struct in6_addr *saddr)
1139 {
1140         switch (opt->type) {
1141         case IPV6_SRCRT_TYPE_0:
1142         case IPV6_SRCRT_STRICT:
1143         case IPV6_SRCRT_TYPE_2:
1144                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1145                 break;
1146         case IPV6_SRCRT_TYPE_4:
1147                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1148                 break;
1149         default:
1150                 break;
1151         }
1152 }
1153
1154 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1155 {
1156         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1157
1158         memcpy(h, opt, ipv6_optlen(opt));
1159         h->nexthdr = *proto;
1160         *proto = type;
1161 }
1162
1163 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1164                           u8 *proto,
1165                           struct in6_addr **daddr, struct in6_addr *saddr)
1166 {
1167         if (opt->srcrt) {
1168                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1169                 /*
1170                  * IPV6_RTHDRDSTOPTS is ignored
1171                  * unless IPV6_RTHDR is set (RFC3542).
1172                  */
1173                 if (opt->dst0opt)
1174                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1175         }
1176         if (opt->hopopt)
1177                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1178 }
1179
1180 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1181 {
1182         if (opt->dst1opt)
1183                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1184 }
1185 EXPORT_SYMBOL(ipv6_push_frag_opts);
1186
1187 struct ipv6_txoptions *
1188 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1189 {
1190         struct ipv6_txoptions *opt2;
1191
1192         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1193         if (opt2) {
1194                 long dif = (char *)opt2 - (char *)opt;
1195                 memcpy(opt2, opt, opt->tot_len);
1196                 if (opt2->hopopt)
1197                         *((char **)&opt2->hopopt) += dif;
1198                 if (opt2->dst0opt)
1199                         *((char **)&opt2->dst0opt) += dif;
1200                 if (opt2->dst1opt)
1201                         *((char **)&opt2->dst1opt) += dif;
1202                 if (opt2->srcrt)
1203                         *((char **)&opt2->srcrt) += dif;
1204                 refcount_set(&opt2->refcnt, 1);
1205         }
1206         return opt2;
1207 }
1208 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1209
1210 static void ipv6_renew_option(int renewtype,
1211                               struct ipv6_opt_hdr **dest,
1212                               struct ipv6_opt_hdr *old,
1213                               struct ipv6_opt_hdr *new,
1214                               int newtype, char **p)
1215 {
1216         struct ipv6_opt_hdr *src;
1217
1218         src = (renewtype == newtype ? new : old);
1219         if (!src)
1220                 return;
1221
1222         memcpy(*p, src, ipv6_optlen(src));
1223         *dest = (struct ipv6_opt_hdr *)*p;
1224         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1225 }
1226
1227 /**
1228  * ipv6_renew_options - replace a specific ext hdr with a new one.
1229  *
1230  * @sk: sock from which to allocate memory
1231  * @opt: original options
1232  * @newtype: option type to replace in @opt
1233  * @newopt: new option of type @newtype to replace (user-mem)
1234  *
1235  * Returns a new set of options which is a copy of @opt with the
1236  * option type @newtype replaced with @newopt.
1237  *
1238  * @opt may be NULL, in which case a new set of options is returned
1239  * containing just @newopt.
1240  *
1241  * @newopt may be NULL, in which case the specified option type is
1242  * not copied into the new set of options.
1243  *
1244  * The new set of options is allocated from the socket option memory
1245  * buffer of @sk.
1246  */
1247 struct ipv6_txoptions *
1248 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1249                    int newtype, struct ipv6_opt_hdr *newopt)
1250 {
1251         int tot_len = 0;
1252         char *p;
1253         struct ipv6_txoptions *opt2;
1254
1255         if (opt) {
1256                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1257                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1258                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1259                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1260                 if (newtype != IPV6_RTHDR && opt->srcrt)
1261                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1262                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1263                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1264         }
1265
1266         if (newopt)
1267                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1268
1269         if (!tot_len)
1270                 return NULL;
1271
1272         tot_len += sizeof(*opt2);
1273         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1274         if (!opt2)
1275                 return ERR_PTR(-ENOBUFS);
1276
1277         memset(opt2, 0, tot_len);
1278         refcount_set(&opt2->refcnt, 1);
1279         opt2->tot_len = tot_len;
1280         p = (char *)(opt2 + 1);
1281
1282         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1283                           (opt ? opt->hopopt : NULL),
1284                           newopt, newtype, &p);
1285         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1286                           (opt ? opt->dst0opt : NULL),
1287                           newopt, newtype, &p);
1288         ipv6_renew_option(IPV6_RTHDR,
1289                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1290                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1291                           newopt, newtype, &p);
1292         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1293                           (opt ? opt->dst1opt : NULL),
1294                           newopt, newtype, &p);
1295
1296         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1297                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1298                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1299         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1300
1301         return opt2;
1302 }
1303
1304 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1305                                           struct ipv6_txoptions *opt)
1306 {
1307         /*
1308          * ignore the dest before srcrt unless srcrt is being included.
1309          * --yoshfuji
1310          */
1311         if (opt && opt->dst0opt && !opt->srcrt) {
1312                 if (opt_space != opt) {
1313                         memcpy(opt_space, opt, sizeof(*opt_space));
1314                         opt = opt_space;
1315                 }
1316                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1317                 opt->dst0opt = NULL;
1318         }
1319
1320         return opt;
1321 }
1322 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1323
1324 /**
1325  * fl6_update_dst - update flowi destination address with info given
1326  *                  by srcrt option, if any.
1327  *
1328  * @fl6: flowi6 for which daddr is to be updated
1329  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1330  * @orig: copy of original daddr address if modified
1331  *
1332  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1333  * and initial value of fl6->daddr set in orig
1334  */
1335 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1336                                 const struct ipv6_txoptions *opt,
1337                                 struct in6_addr *orig)
1338 {
1339         if (!opt || !opt->srcrt)
1340                 return NULL;
1341
1342         *orig = fl6->daddr;
1343
1344         switch (opt->srcrt->type) {
1345         case IPV6_SRCRT_TYPE_0:
1346         case IPV6_SRCRT_STRICT:
1347         case IPV6_SRCRT_TYPE_2:
1348                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1349                 break;
1350         case IPV6_SRCRT_TYPE_4:
1351         {
1352                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1353
1354                 fl6->daddr = srh->segments[srh->segments_left];
1355                 break;
1356         }
1357         default:
1358                 return NULL;
1359         }
1360
1361         return orig;
1362 }
1363 EXPORT_SYMBOL_GPL(fl6_update_dst);