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 = nh[off + 1] + 2;
 139                 int i;
 140
 141                 switch (nh[off]) {
 142                 case IPV6_TLV_PAD1:
 143                         optlen = 1;
 144                         padlen++;
 145                         if (padlen > 7)
 146                                 goto bad;
 147                         break;
 148
 149                 case IPV6_TLV_PADN:
 150                         /* RFC 2460 states that the purpose of PadN is
 151                          * to align the containing header to multiples
 152                          * of 8. 7 is therefore the highest valid value.
 153                          * See also RFC 4942, Section 2.1.9.5.
 154                          */
 155                         padlen += optlen;
 156                         if (padlen > 7)
 157                                 goto bad;
 158                         /* RFC 4942 recommends receiving hosts to
 159                          * actively check PadN payload to contain
 160                          * only zeroes.
 161                          */
 162                         for (i = 2; i < optlen; i++) {
 163                                 if (nh[off + i] != 0)
 164                                         goto bad;
 165                         }
 166                         break;
 167
 168                 default: /* Other TLV code so scan list */
 169                         if (optlen > len)
 170                                 goto bad;
 171
 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                         break;
 192                 }
 193                 off += optlen;
 194                 len -= optlen;
 195         }
 196
 197         if (len == 0)
 198                 return true;
 199 bad:
 200         kfree_skb(skb);
 201         return false;
 202 }
 203
 204 /*****************************
 205   Destination options header.
 206  *****************************/
 207
 208 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 209 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
 210 {
 211         struct ipv6_destopt_hao *hao;
 212         struct inet6_skb_parm *opt = IP6CB(skb);
 213         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 214         int ret;
 215
 216         if (opt->dsthao) {
 217                 net_dbg_ratelimited("hao duplicated\n");
 218                 goto discard;
 219         }
 220         opt->dsthao = opt->dst1;
 221         opt->dst1 = 0;
 222
 223         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 224
 225         if (hao->length != 16) {
 226                 net_dbg_ratelimited("hao invalid option length = %d\n",
 227                                     hao->length);
 228                 goto discard;
 229         }
 230
 231         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 232                 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
 233                                     &hao->addr);
 234                 goto discard;
 235         }
 236
 237         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 238                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 239         if (unlikely(ret < 0))
 240                 goto discard;
 241
 242         if (skb_cloned(skb)) {
 243                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 244                         goto discard;
 245
 246                 /* update all variable using below by copied skbuff */
 247                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
 248                                                   optoff);
 249                 ipv6h = ipv6_hdr(skb);
 250         }
 251
 252         if (skb->ip_summed == CHECKSUM_COMPLETE)
 253                 skb->ip_summed = CHECKSUM_NONE;
 254
 255         swap(ipv6h->saddr, hao->addr);
 256
 257         if (skb->tstamp == 0)
 258                 __net_timestamp(skb);
 259
 260         return true;
 261
 262  discard:
 263         kfree_skb(skb);
 264         return false;
 265 }
 266 #endif
 267
 268 static const struct tlvtype_proc tlvprocdestopt_lst[] = {
 269 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 270         {
 271                 .type   = IPV6_TLV_HAO,
 272                 .func   = ipv6_dest_hao,
 273         },
 274 #endif
 275         {-1,                    NULL}
 276 };
 277
 278 static int ipv6_destopt_rcv(struct sk_buff *skb)
 279 {
 280         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 281         struct inet6_skb_parm *opt = IP6CB(skb);
 282 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 283         __u16 dstbuf;
 284 #endif
 285         struct dst_entry *dst = skb_dst(skb);
 286         struct net *net = dev_net(skb->dev);
 287         int extlen;
 288
 289         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 290             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 291                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 292                 __IP6_INC_STATS(dev_net(dst->dev), idev,
 293                                 IPSTATS_MIB_INHDRERRORS);
 294 fail_and_free:
 295                 kfree_skb(skb);
 296                 return -1;
 297         }
 298
 299         extlen = (skb_transport_header(skb)[1] + 1) << 3;
 300         if (extlen > net->ipv6.sysctl.max_dst_opts_len)
 301                 goto fail_and_free;
 302
 303         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 304 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 305         dstbuf = opt->dst1;
 306 #endif
 307
 308         if (ip6_parse_tlv(tlvprocdestopt_lst, skb,
 309                           init_net.ipv6.sysctl.max_dst_opts_cnt)) {
 310                 skb->transport_header += extlen;
 311                 opt = IP6CB(skb);
 312 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 313                 opt->nhoff = dstbuf;
 314 #else
 315                 opt->nhoff = opt->dst1;
 316 #endif
 317                 return 1;
 318         }
 319
 320         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 321         return -1;
 322 }
 323
 324 static void seg6_update_csum(struct sk_buff *skb)
 325 {
 326         struct ipv6_sr_hdr *hdr;
 327         struct in6_addr *addr;
 328         __be32 from, to;
 329
 330         /* srh is at transport offset and seg_left is already decremented
 331          * but daddr is not yet updated with next segment
 332          */
 333
 334         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 335         addr = hdr->segments + hdr->segments_left;
 336
 337         hdr->segments_left++;
 338         from = *(__be32 *)hdr;
 339
 340         hdr->segments_left--;
 341         to = *(__be32 *)hdr;
 342
 343         /* update skb csum with diff resulting from seg_left decrement */
 344
 345         update_csum_diff4(skb, from, to);
 346
 347         /* compute csum diff between current and next segment and update */
 348
 349         update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
 350                            (__be32 *)addr);
 351 }
 352
 353 static int ipv6_srh_rcv(struct sk_buff *skb)
 354 {
 355         struct inet6_skb_parm *opt = IP6CB(skb);
 356         struct net *net = dev_net(skb->dev);
 357         struct ipv6_sr_hdr *hdr;
 358         struct inet6_dev *idev;
 359         struct in6_addr *addr;
 360         int accept_seg6;
 361
 362         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 363
 364         idev = __in6_dev_get(skb->dev);
 365
 366         accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
 367         if (accept_seg6 > idev->cnf.seg6_enabled)
 368                 accept_seg6 = idev->cnf.seg6_enabled;
 369
 370         if (!accept_seg6) {
 371                 kfree_skb(skb);
 372                 return -1;
 373         }
 374
 375 #ifdef CONFIG_IPV6_SEG6_HMAC
 376         if (!seg6_hmac_validate_skb(skb)) {
 377                 kfree_skb(skb);
 378                 return -1;
 379         }
 380 #endif
 381
 382 looped_back:
 383         if (hdr->segments_left == 0) {
 384                 if (hdr->nexthdr == NEXTHDR_IPV6) {
 385                         int offset = (hdr->hdrlen + 1) << 3;
 386
 387                         skb_postpull_rcsum(skb, skb_network_header(skb),
 388                                            skb_network_header_len(skb));
 389
 390                         if (!pskb_pull(skb, offset)) {
 391                                 kfree_skb(skb);
 392                                 return -1;
 393                         }
 394                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 395                                            offset);
 396
 397                         skb_reset_network_header(skb);
 398                         skb_reset_transport_header(skb);
 399                         skb->encapsulation = 0;
 400
 401                         __skb_tunnel_rx(skb, skb->dev, net);
 402
 403                         netif_rx(skb);
 404                         return -1;
 405                 }
 406
 407                 opt->srcrt = skb_network_header_len(skb);
 408                 opt->lastopt = opt->srcrt;
 409                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 410                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 411
 412                 return 1;
 413         }
 414
 415         if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
 416                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 417                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 418                                   ((&hdr->segments_left) -
 419                                    skb_network_header(skb)));
 420                 return -1;
 421         }
 422
 423         if (skb_cloned(skb)) {
 424                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 425                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 426                                         IPSTATS_MIB_OUTDISCARDS);
 427                         kfree_skb(skb);
 428                         return -1;
 429                 }
 430         }
 431
 432         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 433
 434         hdr->segments_left--;
 435         addr = hdr->segments + hdr->segments_left;
 436
 437         skb_push(skb, sizeof(struct ipv6hdr));
 438
 439         if (skb->ip_summed == CHECKSUM_COMPLETE)
 440                 seg6_update_csum(skb);
 441
 442         ipv6_hdr(skb)->daddr = *addr;
 443
 444         skb_dst_drop(skb);
 445
 446         ip6_route_input(skb);
 447
 448         if (skb_dst(skb)->error) {
 449                 dst_input(skb);
 450                 return -1;
 451         }
 452
 453         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 454                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 455                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 456                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 457                                     ICMPV6_EXC_HOPLIMIT, 0);
 458                         kfree_skb(skb);
 459                         return -1;
 460                 }
 461                 ipv6_hdr(skb)->hop_limit--;
 462
 463                 skb_pull(skb, sizeof(struct ipv6hdr));
 464                 goto looped_back;
 465         }
 466
 467         dst_input(skb);
 468
 469         return -1;
 470 }
 471
 472 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 473 {
 474         struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
 475         struct inet6_skb_parm *opt = IP6CB(skb);
 476         struct net *net = dev_net(skb->dev);
 477         struct inet6_dev *idev;
 478         struct ipv6hdr *oldhdr;
 479         struct in6_addr addr;
 480         unsigned char *buf;
 481         int accept_rpl_seg;
 482         int i, err;
 483         u64 n = 0;
 484         u32 r;
 485
 486         idev = __in6_dev_get(skb->dev);
 487
 488         accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
 489         if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
 490                 accept_rpl_seg = idev->cnf.rpl_seg_enabled;
 491
 492         if (!accept_rpl_seg) {
 493                 kfree_skb(skb);
 494                 return -1;
 495         }
 496
 497 looped_back:
 498         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 499
 500         if (hdr->segments_left == 0) {
 501                 if (hdr->nexthdr == NEXTHDR_IPV6) {
 502                         int offset = (hdr->hdrlen + 1) << 3;
 503
 504                         skb_postpull_rcsum(skb, skb_network_header(skb),
 505                                            skb_network_header_len(skb));
 506
 507                         if (!pskb_pull(skb, offset)) {
 508                                 kfree_skb(skb);
 509                                 return -1;
 510                         }
 511                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 512                                            offset);
 513
 514                         skb_reset_network_header(skb);
 515                         skb_reset_transport_header(skb);
 516                         skb->encapsulation = 0;
 517
 518                         __skb_tunnel_rx(skb, skb->dev, net);
 519
 520                         netif_rx(skb);
 521                         return -1;
 522                 }
 523
 524                 opt->srcrt = skb_network_header_len(skb);
 525                 opt->lastopt = opt->srcrt;
 526                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 527                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 528
 529                 return 1;
 530         }
 531
 532         if (!pskb_may_pull(skb, sizeof(*hdr))) {
 533                 kfree_skb(skb);
 534                 return -1;
 535         }
 536
 537         n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
 538         r = do_div(n, (16 - hdr->cmpri));
 539         /* checks if calculation was without remainder and n fits into
 540          * unsigned char which is segments_left field. Should not be
 541          * higher than that.
 542          */
 543         if (r || (n + 1) > 255) {
 544                 kfree_skb(skb);
 545                 return -1;
 546         }
 547
 548         if (hdr->segments_left > n + 1) {
 549                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 550                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 551                                   ((&hdr->segments_left) -
 552                                    skb_network_header(skb)));
 553                 return -1;
 554         }
 555
 556         if (skb_cloned(skb)) {
 557                 if (pskb_expand_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE, 0,
 558                                      GFP_ATOMIC)) {
 559                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 560                                         IPSTATS_MIB_OUTDISCARDS);
 561                         kfree_skb(skb);
 562                         return -1;
 563                 }
 564         } else {
 565                 err = skb_cow_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE);
 566                 if (unlikely(err)) {
 567                         kfree_skb(skb);
 568                         return -1;
 569                 }
 570         }
 571
 572         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 573
 574         if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
 575                                                   hdr->cmpre))) {
 576                 kfree_skb(skb);
 577                 return -1;
 578         }
 579
 580         hdr->segments_left--;
 581         i = n - hdr->segments_left;
 582
 583         buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
 584         if (unlikely(!buf)) {
 585                 kfree_skb(skb);
 586                 return -1;
 587         }
 588
 589         ohdr = (struct ipv6_rpl_sr_hdr *)buf;
 590         ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 591         chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 592
 593         if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
 594             (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
 595                 kfree_skb(skb);
 596                 kfree(buf);
 597                 return -1;
 598         }
 599
 600         err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
 601         if (err) {
 602                 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
 603                 kfree_skb(skb);
 604                 kfree(buf);
 605                 return -1;
 606         }
 607
 608         addr = ipv6_hdr(skb)->daddr;
 609         ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
 610         ohdr->rpl_segaddr[i] = addr;
 611
 612         ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
 613
 614         oldhdr = ipv6_hdr(skb);
 615
 616         skb_pull(skb, ((hdr->hdrlen + 1) << 3));
 617         skb_postpull_rcsum(skb, oldhdr,
 618                            sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
 619         skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
 620         skb_reset_network_header(skb);
 621         skb_mac_header_rebuild(skb);
 622         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 623
 624         memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
 625         memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
 626
 627         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 628         skb_postpush_rcsum(skb, ipv6_hdr(skb),
 629                            sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
 630
 631         kfree(buf);
 632
 633         skb_dst_drop(skb);
 634
 635         ip6_route_input(skb);
 636
 637         if (skb_dst(skb)->error) {
 638                 dst_input(skb);
 639                 return -1;
 640         }
 641
 642         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 643                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 644                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 645                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 646                                     ICMPV6_EXC_HOPLIMIT, 0);
 647                         kfree_skb(skb);
 648                         return -1;
 649                 }
 650                 ipv6_hdr(skb)->hop_limit--;
 651
 652                 skb_pull(skb, sizeof(struct ipv6hdr));
 653                 goto looped_back;
 654         }
 655
 656         dst_input(skb);
 657
 658         return -1;
 659 }
 660
 661 /********************************
 662   Routing header.
 663  ********************************/
 664
 665 /* called with rcu_read_lock() */
 666 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 667 {
 668         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 669         struct inet6_skb_parm *opt = IP6CB(skb);
 670         struct in6_addr *addr = NULL;
 671         struct in6_addr daddr;
 672         int n, i;
 673         struct ipv6_rt_hdr *hdr;
 674         struct rt0_hdr *rthdr;
 675         struct net *net = dev_net(skb->dev);
 676         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 677
 678         idev = __in6_dev_get(skb->dev);
 679         if (idev && accept_source_route > idev->cnf.accept_source_route)
 680                 accept_source_route = idev->cnf.accept_source_route;
 681
 682         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 683             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 684                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 685                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 686                 kfree_skb(skb);
 687                 return -1;
 688         }
 689
 690         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 691
 692         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 693             skb->pkt_type != PACKET_HOST) {
 694                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 695                 kfree_skb(skb);
 696                 return -1;
 697         }
 698
 699         switch (hdr->type) {
 700         case IPV6_SRCRT_TYPE_4:
 701                 /* segment routing */
 702                 return ipv6_srh_rcv(skb);
 703         case IPV6_SRCRT_TYPE_3:
 704                 /* rpl segment routing */
 705                 return ipv6_rpl_srh_rcv(skb);
 706         default:
 707                 break;
 708         }
 709
 710 looped_back:
 711         if (hdr->segments_left == 0) {
 712                 switch (hdr->type) {
 713 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 714                 case IPV6_SRCRT_TYPE_2:
 715                         /* Silently discard type 2 header unless it was
 716                          * processed by own
 717                          */
 718                         if (!addr) {
 719                                 __IP6_INC_STATS(net, idev,
 720                                                 IPSTATS_MIB_INADDRERRORS);
 721                                 kfree_skb(skb);
 722                                 return -1;
 723                         }
 724                         break;
 725 #endif
 726                 default:
 727                         break;
 728                 }
 729
 730                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 731                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 732                 opt->dst0 = opt->dst1;
 733                 opt->dst1 = 0;
 734                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 735                 return 1;
 736         }
 737
 738         switch (hdr->type) {
 739 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 740         case IPV6_SRCRT_TYPE_2:
 741                 if (accept_source_route < 0)
 742                         goto unknown_rh;
 743                 /* Silently discard invalid RTH type 2 */
 744                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 745                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 746                         kfree_skb(skb);
 747                         return -1;
 748                 }
 749                 break;
 750 #endif
 751         default:
 752                 goto unknown_rh;
 753         }
 754
 755         /*
 756          *      This is the routing header forwarding algorithm from
 757          *      RFC 2460, page 16.
 758          */
 759
 760         n = hdr->hdrlen >> 1;
 761
 762         if (hdr->segments_left > n) {
 763                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 764                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 765                                   ((&hdr->segments_left) -
 766                                    skb_network_header(skb)));
 767                 return -1;
 768         }
 769
 770         /* We are about to mangle packet header. Be careful!
 771            Do not damage packets queued somewhere.
 772          */
 773         if (skb_cloned(skb)) {
 774                 /* the copy is a forwarded packet */
 775                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 776                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 777                                         IPSTATS_MIB_OUTDISCARDS);
 778                         kfree_skb(skb);
 779                         return -1;
 780                 }
 781                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 782         }
 783
 784         if (skb->ip_summed == CHECKSUM_COMPLETE)
 785                 skb->ip_summed = CHECKSUM_NONE;
 786
 787         i = n - --hdr->segments_left;
 788
 789         rthdr = (struct rt0_hdr *) hdr;
 790         addr = rthdr->addr;
 791         addr += i - 1;
 792
 793         switch (hdr->type) {
 794 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 795         case IPV6_SRCRT_TYPE_2:
 796                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 797                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 798                                      IPPROTO_ROUTING) < 0) {
 799                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 800                         kfree_skb(skb);
 801                         return -1;
 802                 }
 803                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 804                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 805                         kfree_skb(skb);
 806                         return -1;
 807                 }
 808                 break;
 809 #endif
 810         default:
 811                 break;
 812         }
 813
 814         if (ipv6_addr_is_multicast(addr)) {
 815                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 816                 kfree_skb(skb);
 817                 return -1;
 818         }
 819
 820         daddr = *addr;
 821         *addr = ipv6_hdr(skb)->daddr;
 822         ipv6_hdr(skb)->daddr = daddr;
 823
 824         skb_dst_drop(skb);
 825         ip6_route_input(skb);
 826         if (skb_dst(skb)->error) {
 827                 skb_push(skb, skb->data - skb_network_header(skb));
 828                 dst_input(skb);
 829                 return -1;
 830         }
 831
 832         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 833                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 834                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 835                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 836                                     0);
 837                         kfree_skb(skb);
 838                         return -1;
 839                 }
 840                 ipv6_hdr(skb)->hop_limit--;
 841                 goto looped_back;
 842         }
 843
 844         skb_push(skb, skb->data - skb_network_header(skb));
 845         dst_input(skb);
 846         return -1;
 847
 848 unknown_rh:
 849         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 850         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 851                           (&hdr->type) - skb_network_header(skb));
 852         return -1;
 853 }
 854
 855 static const struct inet6_protocol rthdr_protocol = {
 856         .handler        =       ipv6_rthdr_rcv,
 857         .flags          =       INET6_PROTO_NOPOLICY,
 858 };
 859
 860 static const struct inet6_protocol destopt_protocol = {
 861         .handler        =       ipv6_destopt_rcv,
 862         .flags          =       INET6_PROTO_NOPOLICY,
 863 };
 864
 865 static const struct inet6_protocol nodata_protocol = {
 866         .handler        =       dst_discard,
 867         .flags          =       INET6_PROTO_NOPOLICY,
 868 };
 869
 870 int __init ipv6_exthdrs_init(void)
 871 {
 872         int ret;
 873
 874         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 875         if (ret)
 876                 goto out;
 877
 878         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 879         if (ret)
 880                 goto out_rthdr;
 881
 882         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 883         if (ret)
 884                 goto out_destopt;
 885
 886 out:
 887         return ret;
 888 out_destopt:
 889         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 890 out_rthdr:
 891         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 892         goto out;
 893 };
 894
 895 void ipv6_exthdrs_exit(void)
 896 {
 897         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 898         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 899         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 900 }
 901
 902 /**********************************
 903   Hop-by-hop options.
 904  **********************************/
 905
 906 /*
 907  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 908  */
 909 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb)
 910 {
 911         return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev);
 912 }
 913
 914 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 915 {
 916         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 917 }
 918
 919 /* Router Alert as of RFC 2711 */
 920
 921 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 922 {
 923         const unsigned char *nh = skb_network_header(skb);
 924
 925         if (nh[optoff + 1] == 2) {
 926                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 927                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 928                 return true;
 929         }
 930         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 931                             nh[optoff + 1]);
 932         kfree_skb(skb);
 933         return false;
 934 }
 935
 936 /* Jumbo payload */
 937
 938 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 939 {
 940         const unsigned char *nh = skb_network_header(skb);
 941         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 942         struct net *net = ipv6_skb_net(skb);
 943         u32 pkt_len;
 944
 945         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 946                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
 947                                     nh[optoff+1]);
 948                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 949                 goto drop;
 950         }
 951
 952         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
 953         if (pkt_len <= IPV6_MAXPLEN) {
 954                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 955                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
 956                 return false;
 957         }
 958         if (ipv6_hdr(skb)->payload_len) {
 959                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 960                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
 961                 return false;
 962         }
 963
 964         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
 965                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
 966                 goto drop;
 967         }
 968
 969         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
 970                 goto drop;
 971
 972         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
 973         return true;
 974
 975 drop:
 976         kfree_skb(skb);
 977         return false;
 978 }
 979
 980 /* CALIPSO RFC 5570 */
 981
 982 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
 983 {
 984         const unsigned char *nh = skb_network_header(skb);
 985
 986         if (nh[optoff + 1] < 8)
 987                 goto drop;
 988
 989         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
 990                 goto drop;
 991
 992         if (!calipso_validate(skb, nh + optoff))
 993                 goto drop;
 994
 995         return true;
 996
 997 drop:
 998         kfree_skb(skb);
 999         return false;
1000 }
1001
1002 static const struct tlvtype_proc tlvprochopopt_lst[] = {
1003         {
1004                 .type   = IPV6_TLV_ROUTERALERT,
1005                 .func   = ipv6_hop_ra,
1006         },
1007         {
1008                 .type   = IPV6_TLV_JUMBO,
1009                 .func   = ipv6_hop_jumbo,
1010         },
1011         {
1012                 .type   = IPV6_TLV_CALIPSO,
1013                 .func   = ipv6_hop_calipso,
1014         },
1015         { -1, }
1016 };
1017
1018 int ipv6_parse_hopopts(struct sk_buff *skb)
1019 {
1020         struct inet6_skb_parm *opt = IP6CB(skb);
1021         struct net *net = dev_net(skb->dev);
1022         int extlen;
1023
1024         /*
1025          * skb_network_header(skb) is equal to skb->data, and
1026          * skb_network_header_len(skb) is always equal to
1027          * sizeof(struct ipv6hdr) by definition of
1028          * hop-by-hop options.
1029          */
1030         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1031             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1032                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1033 fail_and_free:
1034                 kfree_skb(skb);
1035                 return -1;
1036         }
1037
1038         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1039         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1040                 goto fail_and_free;
1041
1042         opt->flags |= IP6SKB_HOPBYHOP;
1043         if (ip6_parse_tlv(tlvprochopopt_lst, skb,
1044                           init_net.ipv6.sysctl.max_hbh_opts_cnt)) {
1045                 skb->transport_header += extlen;
1046                 opt = IP6CB(skb);
1047                 opt->nhoff = sizeof(struct ipv6hdr);
1048                 return 1;
1049         }
1050         return -1;
1051 }
1052
1053 /*
1054  *      Creating outbound headers.
1055  *
1056  *      "build" functions work when skb is filled from head to tail (datagram)
1057  *      "push"  functions work when headers are added from tail to head (tcp)
1058  *
1059  *      In both cases we assume, that caller reserved enough room
1060  *      for headers.
1061  */
1062
1063 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1064                              struct ipv6_rt_hdr *opt,
1065                              struct in6_addr **addr_p, struct in6_addr *saddr)
1066 {
1067         struct rt0_hdr *phdr, *ihdr;
1068         int hops;
1069
1070         ihdr = (struct rt0_hdr *) opt;
1071
1072         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1073         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1074
1075         hops = ihdr->rt_hdr.hdrlen >> 1;
1076
1077         if (hops > 1)
1078                 memcpy(phdr->addr, ihdr->addr + 1,
1079                        (hops - 1) * sizeof(struct in6_addr));
1080
1081         phdr->addr[hops - 1] = **addr_p;
1082         *addr_p = ihdr->addr;
1083
1084         phdr->rt_hdr.nexthdr = *proto;
1085         *proto = NEXTHDR_ROUTING;
1086 }
1087
1088 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1089                              struct ipv6_rt_hdr *opt,
1090                              struct in6_addr **addr_p, struct in6_addr *saddr)
1091 {
1092         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1093         int plen, hops;
1094
1095         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1096         plen = (sr_ihdr->hdrlen + 1) << 3;
1097
1098         sr_phdr = skb_push(skb, plen);
1099         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1100
1101         hops = sr_ihdr->first_segment + 1;
1102         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1103                (hops - 1) * sizeof(struct in6_addr));
1104
1105         sr_phdr->segments[0] = **addr_p;
1106         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1107
1108         if (sr_ihdr->hdrlen > hops * 2) {
1109                 int tlvs_offset, tlvs_length;
1110
1111                 tlvs_offset = (1 + hops * 2) << 3;
1112                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1113                 memcpy((char *)sr_phdr + tlvs_offset,
1114                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1115         }
1116
1117 #ifdef CONFIG_IPV6_SEG6_HMAC
1118         if (sr_has_hmac(sr_phdr)) {
1119                 struct net *net = NULL;
1120
1121                 if (skb->dev)
1122                         net = dev_net(skb->dev);
1123                 else if (skb->sk)
1124                         net = sock_net(skb->sk);
1125
1126                 WARN_ON(!net);
1127
1128                 if (net)
1129                         seg6_push_hmac(net, saddr, sr_phdr);
1130         }
1131 #endif
1132
1133         sr_phdr->nexthdr = *proto;
1134         *proto = NEXTHDR_ROUTING;
1135 }
1136
1137 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1138                             struct ipv6_rt_hdr *opt,
1139                             struct in6_addr **addr_p, struct in6_addr *saddr)
1140 {
1141         switch (opt->type) {
1142         case IPV6_SRCRT_TYPE_0:
1143         case IPV6_SRCRT_STRICT:
1144         case IPV6_SRCRT_TYPE_2:
1145                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1146                 break;
1147         case IPV6_SRCRT_TYPE_4:
1148                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1149                 break;
1150         default:
1151                 break;
1152         }
1153 }
1154
1155 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1156 {
1157         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1158
1159         memcpy(h, opt, ipv6_optlen(opt));
1160         h->nexthdr = *proto;
1161         *proto = type;
1162 }
1163
1164 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1165                           u8 *proto,
1166                           struct in6_addr **daddr, struct in6_addr *saddr)
1167 {
1168         if (opt->srcrt) {
1169                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1170                 /*
1171                  * IPV6_RTHDRDSTOPTS is ignored
1172                  * unless IPV6_RTHDR is set (RFC3542).
1173                  */
1174                 if (opt->dst0opt)
1175                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1176         }
1177         if (opt->hopopt)
1178                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1179 }
1180
1181 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1182 {
1183         if (opt->dst1opt)
1184                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1185 }
1186 EXPORT_SYMBOL(ipv6_push_frag_opts);
1187
1188 struct ipv6_txoptions *
1189 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1190 {
1191         struct ipv6_txoptions *opt2;
1192
1193         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1194         if (opt2) {
1195                 long dif = (char *)opt2 - (char *)opt;
1196                 memcpy(opt2, opt, opt->tot_len);
1197                 if (opt2->hopopt)
1198                         *((char **)&opt2->hopopt) += dif;
1199                 if (opt2->dst0opt)
1200                         *((char **)&opt2->dst0opt) += dif;
1201                 if (opt2->dst1opt)
1202                         *((char **)&opt2->dst1opt) += dif;
1203                 if (opt2->srcrt)
1204                         *((char **)&opt2->srcrt) += dif;
1205                 refcount_set(&opt2->refcnt, 1);
1206         }
1207         return opt2;
1208 }
1209 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1210
1211 static void ipv6_renew_option(int renewtype,
1212                               struct ipv6_opt_hdr **dest,
1213                               struct ipv6_opt_hdr *old,
1214                               struct ipv6_opt_hdr *new,
1215                               int newtype, char **p)
1216 {
1217         struct ipv6_opt_hdr *src;
1218
1219         src = (renewtype == newtype ? new : old);
1220         if (!src)
1221                 return;
1222
1223         memcpy(*p, src, ipv6_optlen(src));
1224         *dest = (struct ipv6_opt_hdr *)*p;
1225         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1226 }
1227
1228 /**
1229  * ipv6_renew_options - replace a specific ext hdr with a new one.
1230  *
1231  * @sk: sock from which to allocate memory
1232  * @opt: original options
1233  * @newtype: option type to replace in @opt
1234  * @newopt: new option of type @newtype to replace (user-mem)
1235  *
1236  * Returns a new set of options which is a copy of @opt with the
1237  * option type @newtype replaced with @newopt.
1238  *
1239  * @opt may be NULL, in which case a new set of options is returned
1240  * containing just @newopt.
1241  *
1242  * @newopt may be NULL, in which case the specified option type is
1243  * not copied into the new set of options.
1244  *
1245  * The new set of options is allocated from the socket option memory
1246  * buffer of @sk.
1247  */
1248 struct ipv6_txoptions *
1249 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1250                    int newtype, struct ipv6_opt_hdr *newopt)
1251 {
1252         int tot_len = 0;
1253         char *p;
1254         struct ipv6_txoptions *opt2;
1255
1256         if (opt) {
1257                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1258                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1259                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1260                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1261                 if (newtype != IPV6_RTHDR && opt->srcrt)
1262                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1263                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1264                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1265         }
1266
1267         if (newopt)
1268                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1269
1270         if (!tot_len)
1271                 return NULL;
1272
1273         tot_len += sizeof(*opt2);
1274         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1275         if (!opt2)
1276                 return ERR_PTR(-ENOBUFS);
1277
1278         memset(opt2, 0, tot_len);
1279         refcount_set(&opt2->refcnt, 1);
1280         opt2->tot_len = tot_len;
1281         p = (char *)(opt2 + 1);
1282
1283         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1284                           (opt ? opt->hopopt : NULL),
1285                           newopt, newtype, &p);
1286         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1287                           (opt ? opt->dst0opt : NULL),
1288                           newopt, newtype, &p);
1289         ipv6_renew_option(IPV6_RTHDR,
1290                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1291                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1292                           newopt, newtype, &p);
1293         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1294                           (opt ? opt->dst1opt : NULL),
1295                           newopt, newtype, &p);
1296
1297         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1298                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1299                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1300         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1301
1302         return opt2;
1303 }
1304
1305 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1306                                           struct ipv6_txoptions *opt)
1307 {
1308         /*
1309          * ignore the dest before srcrt unless srcrt is being included.
1310          * --yoshfuji
1311          */
1312         if (opt && opt->dst0opt && !opt->srcrt) {
1313                 if (opt_space != opt) {
1314                         memcpy(opt_space, opt, sizeof(*opt_space));
1315                         opt = opt_space;
1316                 }
1317                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1318                 opt->dst0opt = NULL;
1319         }
1320
1321         return opt;
1322 }
1323 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1324
1325 /**
1326  * fl6_update_dst - update flowi destination address with info given
1327  *                  by srcrt option, if any.
1328  *
1329  * @fl6: flowi6 for which daddr is to be updated
1330  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1331  * @orig: copy of original daddr address if modified
1332  *
1333  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1334  * and initial value of fl6->daddr set in orig
1335  */
1336 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1337                                 const struct ipv6_txoptions *opt,
1338                                 struct in6_addr *orig)
1339 {
1340         if (!opt || !opt->srcrt)
1341                 return NULL;
1342
1343         *orig = fl6->daddr;
1344
1345         switch (opt->srcrt->type) {
1346         case IPV6_SRCRT_TYPE_0:
1347         case IPV6_SRCRT_STRICT:
1348         case IPV6_SRCRT_TYPE_2:
1349                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1350                 break;
1351         case IPV6_SRCRT_TYPE_4:
1352         {
1353                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1354
1355                 fl6->daddr = srh->segments[srh->segments_left];
1356                 break;
1357         }
1358         default:
1359                 return NULL;
1360         }
1361
1362         return orig;
1363 }
1364 EXPORT_SYMBOL_GPL(fl6_update_dst);