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 (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
 556                                                   hdr->cmpre))) {
 557                 kfree_skb(skb);
 558                 return -1;
 559         }
 560
 561         hdr->segments_left--;
 562         i = n - hdr->segments_left;
 563
 564         buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
 565         if (unlikely(!buf)) {
 566                 kfree_skb(skb);
 567                 return -1;
 568         }
 569
 570         ohdr = (struct ipv6_rpl_sr_hdr *)buf;
 571         ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 572         chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 573
 574         if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
 575             (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
 576                 kfree_skb(skb);
 577                 kfree(buf);
 578                 return -1;
 579         }
 580
 581         err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
 582         if (err) {
 583                 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
 584                 kfree_skb(skb);
 585                 kfree(buf);
 586                 return -1;
 587         }
 588
 589         addr = ipv6_hdr(skb)->daddr;
 590         ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
 591         ohdr->rpl_segaddr[i] = addr;
 592
 593         ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
 594
 595         oldhdr = ipv6_hdr(skb);
 596
 597         skb_pull(skb, ((hdr->hdrlen + 1) << 3));
 598         skb_postpull_rcsum(skb, oldhdr,
 599                            sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
 600         if (unlikely(!hdr->segments_left)) {
 601                 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
 602                                      GFP_ATOMIC)) {
 603                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
 604                         kfree_skb(skb);
 605                         kfree(buf);
 606                         return -1;
 607                 }
 608
 609                 oldhdr = ipv6_hdr(skb);
 610         }
 611         skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
 612         skb_reset_network_header(skb);
 613         skb_mac_header_rebuild(skb);
 614         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 615
 616         memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
 617         memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
 618
 619         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 620         skb_postpush_rcsum(skb, ipv6_hdr(skb),
 621                            sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
 622
 623         kfree(buf);
 624
 625         skb_dst_drop(skb);
 626
 627         ip6_route_input(skb);
 628
 629         if (skb_dst(skb)->error) {
 630                 dst_input(skb);
 631                 return -1;
 632         }
 633
 634         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 635                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 636                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 637                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 638                                     ICMPV6_EXC_HOPLIMIT, 0);
 639                         kfree_skb(skb);
 640                         return -1;
 641                 }
 642                 ipv6_hdr(skb)->hop_limit--;
 643
 644                 skb_pull(skb, sizeof(struct ipv6hdr));
 645                 goto looped_back;
 646         }
 647
 648         dst_input(skb);
 649
 650         return -1;
 651 }
 652
 653 /********************************
 654   Routing header.
 655  ********************************/
 656
 657 /* called with rcu_read_lock() */
 658 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 659 {
 660         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 661         struct inet6_skb_parm *opt = IP6CB(skb);
 662         struct in6_addr *addr = NULL;
 663         struct in6_addr daddr;
 664         int n, i;
 665         struct ipv6_rt_hdr *hdr;
 666         struct rt0_hdr *rthdr;
 667         struct net *net = dev_net(skb->dev);
 668         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 669
 670         idev = __in6_dev_get(skb->dev);
 671         if (idev && accept_source_route > idev->cnf.accept_source_route)
 672                 accept_source_route = idev->cnf.accept_source_route;
 673
 674         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 675             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 676                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 677                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 678                 kfree_skb(skb);
 679                 return -1;
 680         }
 681
 682         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 683
 684         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 685             skb->pkt_type != PACKET_HOST) {
 686                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 687                 kfree_skb(skb);
 688                 return -1;
 689         }
 690
 691         switch (hdr->type) {
 692         case IPV6_SRCRT_TYPE_4:
 693                 /* segment routing */
 694                 return ipv6_srh_rcv(skb);
 695         case IPV6_SRCRT_TYPE_3:
 696                 /* rpl segment routing */
 697                 return ipv6_rpl_srh_rcv(skb);
 698         default:
 699                 break;
 700         }
 701
 702 looped_back:
 703         if (hdr->segments_left == 0) {
 704                 switch (hdr->type) {
 705 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 706                 case IPV6_SRCRT_TYPE_2:
 707                         /* Silently discard type 2 header unless it was
 708                          * processed by own
 709                          */
 710                         if (!addr) {
 711                                 __IP6_INC_STATS(net, idev,
 712                                                 IPSTATS_MIB_INADDRERRORS);
 713                                 kfree_skb(skb);
 714                                 return -1;
 715                         }
 716                         break;
 717 #endif
 718                 default:
 719                         break;
 720                 }
 721
 722                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 723                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 724                 opt->dst0 = opt->dst1;
 725                 opt->dst1 = 0;
 726                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 727                 return 1;
 728         }
 729
 730         switch (hdr->type) {
 731 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 732         case IPV6_SRCRT_TYPE_2:
 733                 if (accept_source_route < 0)
 734                         goto unknown_rh;
 735                 /* Silently discard invalid RTH type 2 */
 736                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 737                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 738                         kfree_skb(skb);
 739                         return -1;
 740                 }
 741                 break;
 742 #endif
 743         default:
 744                 goto unknown_rh;
 745         }
 746
 747         /*
 748          *      This is the routing header forwarding algorithm from
 749          *      RFC 2460, page 16.
 750          */
 751
 752         n = hdr->hdrlen >> 1;
 753
 754         if (hdr->segments_left > n) {
 755                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 756                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 757                                   ((&hdr->segments_left) -
 758                                    skb_network_header(skb)));
 759                 return -1;
 760         }
 761
 762         /* We are about to mangle packet header. Be careful!
 763            Do not damage packets queued somewhere.
 764          */
 765         if (skb_cloned(skb)) {
 766                 /* the copy is a forwarded packet */
 767                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 768                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 769                                         IPSTATS_MIB_OUTDISCARDS);
 770                         kfree_skb(skb);
 771                         return -1;
 772                 }
 773                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 774         }
 775
 776         if (skb->ip_summed == CHECKSUM_COMPLETE)
 777                 skb->ip_summed = CHECKSUM_NONE;
 778
 779         i = n - --hdr->segments_left;
 780
 781         rthdr = (struct rt0_hdr *) hdr;
 782         addr = rthdr->addr;
 783         addr += i - 1;
 784
 785         switch (hdr->type) {
 786 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 787         case IPV6_SRCRT_TYPE_2:
 788                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 789                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 790                                      IPPROTO_ROUTING) < 0) {
 791                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 792                         kfree_skb(skb);
 793                         return -1;
 794                 }
 795                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 796                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 797                         kfree_skb(skb);
 798                         return -1;
 799                 }
 800                 break;
 801 #endif
 802         default:
 803                 break;
 804         }
 805
 806         if (ipv6_addr_is_multicast(addr)) {
 807                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 808                 kfree_skb(skb);
 809                 return -1;
 810         }
 811
 812         daddr = *addr;
 813         *addr = ipv6_hdr(skb)->daddr;
 814         ipv6_hdr(skb)->daddr = daddr;
 815
 816         skb_dst_drop(skb);
 817         ip6_route_input(skb);
 818         if (skb_dst(skb)->error) {
 819                 skb_push(skb, skb->data - skb_network_header(skb));
 820                 dst_input(skb);
 821                 return -1;
 822         }
 823
 824         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 825                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 826                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 827                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 828                                     0);
 829                         kfree_skb(skb);
 830                         return -1;
 831                 }
 832                 ipv6_hdr(skb)->hop_limit--;
 833                 goto looped_back;
 834         }
 835
 836         skb_push(skb, skb->data - skb_network_header(skb));
 837         dst_input(skb);
 838         return -1;
 839
 840 unknown_rh:
 841         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 842         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 843                           (&hdr->type) - skb_network_header(skb));
 844         return -1;
 845 }
 846
 847 static const struct inet6_protocol rthdr_protocol = {
 848         .handler        =       ipv6_rthdr_rcv,
 849         .flags          =       INET6_PROTO_NOPOLICY,
 850 };
 851
 852 static const struct inet6_protocol destopt_protocol = {
 853         .handler        =       ipv6_destopt_rcv,
 854         .flags          =       INET6_PROTO_NOPOLICY,
 855 };
 856
 857 static const struct inet6_protocol nodata_protocol = {
 858         .handler        =       dst_discard,
 859         .flags          =       INET6_PROTO_NOPOLICY,
 860 };
 861
 862 int __init ipv6_exthdrs_init(void)
 863 {
 864         int ret;
 865
 866         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 867         if (ret)
 868                 goto out;
 869
 870         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 871         if (ret)
 872                 goto out_rthdr;
 873
 874         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 875         if (ret)
 876                 goto out_destopt;
 877
 878 out:
 879         return ret;
 880 out_destopt:
 881         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 882 out_rthdr:
 883         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 884         goto out;
 885 };
 886
 887 void ipv6_exthdrs_exit(void)
 888 {
 889         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 890         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 891         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 892 }
 893
 894 /**********************************
 895   Hop-by-hop options.
 896  **********************************/
 897
 898 /*
 899  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 900  */
 901 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 902 {
 903         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 904 }
 905
 906 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 907 {
 908         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 909 }
 910
 911 /* Router Alert as of RFC 2711 */
 912
 913 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 914 {
 915         const unsigned char *nh = skb_network_header(skb);
 916
 917         if (nh[optoff + 1] == 2) {
 918                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 919                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 920                 return true;
 921         }
 922         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 923                             nh[optoff + 1]);
 924         kfree_skb(skb);
 925         return false;
 926 }
 927
 928 /* Jumbo payload */
 929
 930 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 931 {
 932         const unsigned char *nh = skb_network_header(skb);
 933         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 934         struct net *net = ipv6_skb_net(skb);
 935         u32 pkt_len;
 936
 937         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 938                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 939                                     nh[optoff+1]);
 940                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 941                 goto drop;
 942         }
 943
 944         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 945         if (pkt_len <= IPV6_MAXPLEN) {
 946                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 947                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 948                 return false;
 949         }
 950         if (ipv6_hdr(skb)->payload_len) {
 951                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 952                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 953                 return false;
 954         }
 955
 956         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 957                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 958                 goto drop;
 959         }
 960
 961         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 962                 goto drop;
 963
 964         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
 965         return true;
 966
 967 drop:
 968         kfree_skb(skb);
 969         return false;
 970 }
 971
 972 /* CALIPSO RFC 5570 */
 973
 974 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
 975 {
 976         const unsigned char *nh = skb_network_header(skb);
 977
 978         if (nh[optoff + 1] < 8)
 979                 goto drop;
 980
 981         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
 982                 goto drop;
 983
 984         if (!calipso_validate(skb, nh + optoff))
 985                 goto drop;
 986
 987         return true;
 988
 989 drop:
 990         kfree_skb(skb);
 991         return false;
 992 }
 993
 994 static const struct tlvtype_proc tlvprochopopt_lst[] = {
 995         {
 996                 .type   = IPV6_TLV_ROUTERALERT,
 997                 .func   = ipv6_hop_ra,
 998         },
 999         {
1000                 .type   = IPV6_TLV_JUMBO,
1001                 .func   = ipv6_hop_jumbo,
1002         },
1003         {
1004                 .type   = IPV6_TLV_CALIPSO,
1005                 .func   = ipv6_hop_calipso,
1006         },
1007         { -1, }
1008 };
1009
1010 int ipv6_parse_hopopts(struct sk_buff *skb)
1011 {
1012         struct inet6_skb_parm *opt = IP6CB(skb);
1013         struct net *net = dev_net(skb->dev);
1014         int extlen;
1015
1016         /*
1017          * skb_network_header(skb) is equal to skb->data, and
1018          * skb_network_header_len(skb) is always equal to
1019          * sizeof(struct ipv6hdr) by definition of
1020          * hop-by-hop options.
1021          */
1022         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1023             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1024                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1025 fail_and_free:
1026                 kfree_skb(skb);
1027                 return -1;
1028         }
1029
1030         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1031         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1032                 goto fail_and_free;
1033
1034         opt->flags |= IP6SKB_HOPBYHOP;
1035         if (ip6_parse_tlv(tlvprochopopt_lst, skb,
1036                           net->ipv6.sysctl.max_hbh_opts_cnt)) {
1037                 skb->transport_header += extlen;
1038                 opt = IP6CB(skb);
1039                 opt->nhoff = sizeof(struct ipv6hdr);
1040                 return 1;
1041         }
1042         return -1;
1043 }
1044
1045 /*
1046  *      Creating outbound headers.
1047  *
1048  *      "build" functions work when skb is filled from head to tail (datagram)
1049  *      "push"  functions work when headers are added from tail to head (tcp)
1050  *
1051  *      In both cases we assume, that caller reserved enough room
1052  *      for headers.
1053  */
1054
1055 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1056                              struct ipv6_rt_hdr *opt,
1057                              struct in6_addr **addr_p, struct in6_addr *saddr)
1058 {
1059         struct rt0_hdr *phdr, *ihdr;
1060         int hops;
1061
1062         ihdr = (struct rt0_hdr *) opt;
1063
1064         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1065         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1066
1067         hops = ihdr->rt_hdr.hdrlen >> 1;
1068
1069         if (hops > 1)
1070                 memcpy(phdr->addr, ihdr->addr + 1,
1071                        (hops - 1) * sizeof(struct in6_addr));
1072
1073         phdr->addr[hops - 1] = **addr_p;
1074         *addr_p = ihdr->addr;
1075
1076         phdr->rt_hdr.nexthdr = *proto;
1077         *proto = NEXTHDR_ROUTING;
1078 }
1079
1080 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1081                              struct ipv6_rt_hdr *opt,
1082                              struct in6_addr **addr_p, struct in6_addr *saddr)
1083 {
1084         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1085         int plen, hops;
1086
1087         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1088         plen = (sr_ihdr->hdrlen + 1) << 3;
1089
1090         sr_phdr = skb_push(skb, plen);
1091         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1092
1093         hops = sr_ihdr->first_segment + 1;
1094         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1095                (hops - 1) * sizeof(struct in6_addr));
1096
1097         sr_phdr->segments[0] = **addr_p;
1098         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1099
1100         if (sr_ihdr->hdrlen > hops * 2) {
1101                 int tlvs_offset, tlvs_length;
1102
1103                 tlvs_offset = (1 + hops * 2) << 3;
1104                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1105                 memcpy((char *)sr_phdr + tlvs_offset,
1106                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1107         }
1108
1109 #ifdef CONFIG_IPV6_SEG6_HMAC
1110         if (sr_has_hmac(sr_phdr)) {
1111                 struct net *net = NULL;
1112
1113                 if (skb->dev)
1114                         net = dev_net(skb->dev);
1115                 else if (skb->sk)
1116                         net = sock_net(skb->sk);
1117
1118                 WARN_ON(!net);
1119
1120                 if (net)
1121                         seg6_push_hmac(net, saddr, sr_phdr);
1122         }
1123 #endif
1124
1125         sr_phdr->nexthdr = *proto;
1126         *proto = NEXTHDR_ROUTING;
1127 }
1128
1129 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1130                             struct ipv6_rt_hdr *opt,
1131                             struct in6_addr **addr_p, struct in6_addr *saddr)
1132 {
1133         switch (opt->type) {
1134         case IPV6_SRCRT_TYPE_0:
1135         case IPV6_SRCRT_STRICT:
1136         case IPV6_SRCRT_TYPE_2:
1137                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1138                 break;
1139         case IPV6_SRCRT_TYPE_4:
1140                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1141                 break;
1142         default:
1143                 break;
1144         }
1145 }
1146
1147 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1148 {
1149         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1150
1151         memcpy(h, opt, ipv6_optlen(opt));
1152         h->nexthdr = *proto;
1153         *proto = type;
1154 }
1155
1156 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1157                           u8 *proto,
1158                           struct in6_addr **daddr, struct in6_addr *saddr)
1159 {
1160         if (opt->srcrt) {
1161                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1162                 /*
1163                  * IPV6_RTHDRDSTOPTS is ignored
1164                  * unless IPV6_RTHDR is set (RFC3542).
1165                  */
1166                 if (opt->dst0opt)
1167                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1168         }
1169         if (opt->hopopt)
1170                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1171 }
1172
1173 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1174 {
1175         if (opt->dst1opt)
1176                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1177 }
1178 EXPORT_SYMBOL(ipv6_push_frag_opts);
1179
1180 struct ipv6_txoptions *
1181 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1182 {
1183         struct ipv6_txoptions *opt2;
1184
1185         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1186         if (opt2) {
1187                 long dif = (char *)opt2 - (char *)opt;
1188                 memcpy(opt2, opt, opt->tot_len);
1189                 if (opt2->hopopt)
1190                         *((char **)&opt2->hopopt) += dif;
1191                 if (opt2->dst0opt)
1192                         *((char **)&opt2->dst0opt) += dif;
1193                 if (opt2->dst1opt)
1194                         *((char **)&opt2->dst1opt) += dif;
1195                 if (opt2->srcrt)
1196                         *((char **)&opt2->srcrt) += dif;
1197                 refcount_set(&opt2->refcnt, 1);
1198         }
1199         return opt2;
1200 }
1201 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1202
1203 static void ipv6_renew_option(int renewtype,
1204                               struct ipv6_opt_hdr **dest,
1205                               struct ipv6_opt_hdr *old,
1206                               struct ipv6_opt_hdr *new,
1207                               int newtype, char **p)
1208 {
1209         struct ipv6_opt_hdr *src;
1210
1211         src = (renewtype == newtype ? new : old);
1212         if (!src)
1213                 return;
1214
1215         memcpy(*p, src, ipv6_optlen(src));
1216         *dest = (struct ipv6_opt_hdr *)*p;
1217         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1218 }
1219
1220 /**
1221  * ipv6_renew_options - replace a specific ext hdr with a new one.
1222  *
1223  * @sk: sock from which to allocate memory
1224  * @opt: original options
1225  * @newtype: option type to replace in @opt
1226  * @newopt: new option of type @newtype to replace (user-mem)
1227  *
1228  * Returns a new set of options which is a copy of @opt with the
1229  * option type @newtype replaced with @newopt.
1230  *
1231  * @opt may be NULL, in which case a new set of options is returned
1232  * containing just @newopt.
1233  *
1234  * @newopt may be NULL, in which case the specified option type is
1235  * not copied into the new set of options.
1236  *
1237  * The new set of options is allocated from the socket option memory
1238  * buffer of @sk.
1239  */
1240 struct ipv6_txoptions *
1241 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1242                    int newtype, struct ipv6_opt_hdr *newopt)
1243 {
1244         int tot_len = 0;
1245         char *p;
1246         struct ipv6_txoptions *opt2;
1247
1248         if (opt) {
1249                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1250                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1251                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1252                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1253                 if (newtype != IPV6_RTHDR && opt->srcrt)
1254                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1255                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1256                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1257         }
1258
1259         if (newopt)
1260                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1261
1262         if (!tot_len)
1263                 return NULL;
1264
1265         tot_len += sizeof(*opt2);
1266         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1267         if (!opt2)
1268                 return ERR_PTR(-ENOBUFS);
1269
1270         memset(opt2, 0, tot_len);
1271         refcount_set(&opt2->refcnt, 1);
1272         opt2->tot_len = tot_len;
1273         p = (char *)(opt2 + 1);
1274
1275         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1276                           (opt ? opt->hopopt : NULL),
1277                           newopt, newtype, &p);
1278         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1279                           (opt ? opt->dst0opt : NULL),
1280                           newopt, newtype, &p);
1281         ipv6_renew_option(IPV6_RTHDR,
1282                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1283                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1284                           newopt, newtype, &p);
1285         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1286                           (opt ? opt->dst1opt : NULL),
1287                           newopt, newtype, &p);
1288
1289         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1290                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1291                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1292         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1293
1294         return opt2;
1295 }
1296
1297 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1298                                           struct ipv6_txoptions *opt)
1299 {
1300         /*
1301          * ignore the dest before srcrt unless srcrt is being included.
1302          * --yoshfuji
1303          */
1304         if (opt && opt->dst0opt && !opt->srcrt) {
1305                 if (opt_space != opt) {
1306                         memcpy(opt_space, opt, sizeof(*opt_space));
1307                         opt = opt_space;
1308                 }
1309                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1310                 opt->dst0opt = NULL;
1311         }
1312
1313         return opt;
1314 }
1315 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1316
1317 /**
1318  * fl6_update_dst - update flowi destination address with info given
1319  *                  by srcrt option, if any.
1320  *
1321  * @fl6: flowi6 for which daddr is to be updated
1322  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1323  * @orig: copy of original daddr address if modified
1324  *
1325  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1326  * and initial value of fl6->daddr set in orig
1327  */
1328 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1329                                 const struct ipv6_txoptions *opt,
1330                                 struct in6_addr *orig)
1331 {
1332         if (!opt || !opt->srcrt)
1333                 return NULL;
1334
1335         *orig = fl6->daddr;
1336
1337         switch (opt->srcrt->type) {
1338         case IPV6_SRCRT_TYPE_0:
1339         case IPV6_SRCRT_STRICT:
1340         case IPV6_SRCRT_TYPE_2:
1341                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1342                 break;
1343         case IPV6_SRCRT_TYPE_4:
1344         {
1345                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1346
1347                 fl6->daddr = srh->segments[srh->segments_left];
1348                 break;
1349         }
1350         default:
1351                 return NULL;
1352         }
1353
1354         return orig;
1355 }
1356 EXPORT_SYMBOL_GPL(fl6_update_dst);