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 #include <linux/ioam6.h>
  53 #include <net/ioam6.h>
  54 #include <net/dst_metadata.h>
  55
  56 #include <linux/uaccess.h>
  57
  58 /*********************
  59   Generic functions
  60  *********************/
  61
  62 /* An unknown option is detected, decide what to do */
  63
  64 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff,
  65                                bool disallow_unknowns)
  66 {
  67         if (disallow_unknowns) {
  68                 /* If unknown TLVs are disallowed by configuration
  69                  * then always silently drop packet. Note this also
  70                  * means no ICMP parameter problem is sent which
  71                  * could be a good property to mitigate a reflection DOS
  72                  * attack.
  73                  */
  74
  75                 goto drop;
  76         }
  77
  78         switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) {
  79         case 0: /* ignore */
  80                 return true;
  81
  82         case 1: /* drop packet */
  83                 break;
  84
  85         case 3: /* Send ICMP if not a multicast address and drop packet */
  86                 /* Actually, it is redundant check. icmp_send
  87                    will recheck in any case.
  88                  */
  89                 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr))
  90                         break;
  91                 fallthrough;
  92         case 2: /* send ICMP PARM PROB regardless and drop packet */
  93                 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff);
  94                 return false;
  95         }
  96
  97 drop:
  98         kfree_skb(skb);
  99         return false;
 100 }
 101
 102 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff);
 103 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff);
 104 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff);
 105 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff);
 106 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 107 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff);
 108 #endif
 109
 110 /* Parse tlv encoded option header (hop-by-hop or destination) */
 111
 112 static bool ip6_parse_tlv(bool hopbyhop,
 113                           struct sk_buff *skb,
 114                           int max_count)
 115 {
 116         int len = (skb_transport_header(skb)[1] + 1) << 3;
 117         const unsigned char *nh = skb_network_header(skb);
 118         int off = skb_network_header_len(skb);
 119         bool disallow_unknowns = false;
 120         int tlv_count = 0;
 121         int padlen = 0;
 122
 123         if (unlikely(max_count < 0)) {
 124                 disallow_unknowns = true;
 125                 max_count = -max_count;
 126         }
 127
 128         if (skb_transport_offset(skb) + len > skb_headlen(skb))
 129                 goto bad;
 130
 131         off += 2;
 132         len -= 2;
 133
 134         while (len > 0) {
 135                 int optlen, i;
 136
 137                 if (nh[off] == IPV6_TLV_PAD1) {
 138                         padlen++;
 139                         if (padlen > 7)
 140                                 goto bad;
 141                         off++;
 142                         len--;
 143                         continue;
 144                 }
 145                 if (len < 2)
 146                         goto bad;
 147                 optlen = nh[off + 1] + 2;
 148                 if (optlen > len)
 149                         goto bad;
 150
 151                 if (nh[off] == IPV6_TLV_PADN) {
 152                         /* RFC 2460 states that the purpose of PadN is
 153                          * to align the containing header to multiples
 154                          * of 8. 7 is therefore the highest valid value.
 155                          * See also RFC 4942, Section 2.1.9.5.
 156                          */
 157                         padlen += optlen;
 158                         if (padlen > 7)
 159                                 goto bad;
 160                         /* RFC 4942 recommends receiving hosts to
 161                          * actively check PadN payload to contain
 162                          * only zeroes.
 163                          */
 164                         for (i = 2; i < optlen; i++) {
 165                                 if (nh[off + i] != 0)
 166                                         goto bad;
 167                         }
 168                 } else {
 169                         tlv_count++;
 170                         if (tlv_count > max_count)
 171                                 goto bad;
 172
 173                         if (hopbyhop) {
 174                                 switch (nh[off]) {
 175                                 case IPV6_TLV_ROUTERALERT:
 176                                         if (!ipv6_hop_ra(skb, off))
 177                                                 return false;
 178                                         break;
 179                                 case IPV6_TLV_IOAM:
 180                                         if (!ipv6_hop_ioam(skb, off))
 181                                                 return false;
 182                                         break;
 183                                 case IPV6_TLV_JUMBO:
 184                                         if (!ipv6_hop_jumbo(skb, off))
 185                                                 return false;
 186                                         break;
 187                                 case IPV6_TLV_CALIPSO:
 188                                         if (!ipv6_hop_calipso(skb, off))
 189                                                 return false;
 190                                         break;
 191                                 default:
 192                                         if (!ip6_tlvopt_unknown(skb, off,
 193                                                                 disallow_unknowns))
 194                                                 return false;
 195                                         break;
 196                                 }
 197                         } else {
 198                                 switch (nh[off]) {
 199 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 200                                 case IPV6_TLV_HAO:
 201                                         if (!ipv6_dest_hao(skb, off))
 202                                                 return false;
 203                                         break;
 204 #endif
 205                                 default:
 206                                         if (!ip6_tlvopt_unknown(skb, off,
 207                                                                 disallow_unknowns))
 208                                                 return false;
 209                                         break;
 210                                 }
 211                         }
 212                         padlen = 0;
 213                 }
 214                 off += optlen;
 215                 len -= optlen;
 216         }
 217
 218         if (len == 0)
 219                 return true;
 220 bad:
 221         kfree_skb(skb);
 222         return false;
 223 }
 224
 225 /*****************************
 226   Destination options header.
 227  *****************************/
 228
 229 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 230 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff)
 231 {
 232         struct ipv6_destopt_hao *hao;
 233         struct inet6_skb_parm *opt = IP6CB(skb);
 234         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
 235         int ret;
 236
 237         if (opt->dsthao) {
 238                 net_dbg_ratelimited("hao duplicated\n");
 239                 goto discard;
 240         }
 241         opt->dsthao = opt->dst1;
 242         opt->dst1 = 0;
 243
 244         hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff);
 245
 246         if (hao->length != 16) {
 247                 net_dbg_ratelimited("hao invalid option length = %d\n",
 248                                     hao->length);
 249                 goto discard;
 250         }
 251
 252         if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) {
 253                 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n",
 254                                     &hao->addr);
 255                 goto discard;
 256         }
 257
 258         ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr,
 259                                (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS);
 260         if (unlikely(ret < 0))
 261                 goto discard;
 262
 263         if (skb_cloned(skb)) {
 264                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 265                         goto discard;
 266
 267                 /* update all variable using below by copied skbuff */
 268                 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) +
 269                                                   optoff);
 270                 ipv6h = ipv6_hdr(skb);
 271         }
 272
 273         if (skb->ip_summed == CHECKSUM_COMPLETE)
 274                 skb->ip_summed = CHECKSUM_NONE;
 275
 276         swap(ipv6h->saddr, hao->addr);
 277
 278         if (skb->tstamp == 0)
 279                 __net_timestamp(skb);
 280
 281         return true;
 282
 283  discard:
 284         kfree_skb(skb);
 285         return false;
 286 }
 287 #endif
 288
 289 static int ipv6_destopt_rcv(struct sk_buff *skb)
 290 {
 291         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 292         struct inet6_skb_parm *opt = IP6CB(skb);
 293 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 294         __u16 dstbuf;
 295 #endif
 296         struct dst_entry *dst = skb_dst(skb);
 297         struct net *net = dev_net(skb->dev);
 298         int extlen;
 299
 300         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 301             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 302                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 303                 __IP6_INC_STATS(dev_net(dst->dev), idev,
 304                                 IPSTATS_MIB_INHDRERRORS);
 305 fail_and_free:
 306                 kfree_skb(skb);
 307                 return -1;
 308         }
 309
 310         extlen = (skb_transport_header(skb)[1] + 1) << 3;
 311         if (extlen > net->ipv6.sysctl.max_dst_opts_len)
 312                 goto fail_and_free;
 313
 314         opt->lastopt = opt->dst1 = skb_network_header_len(skb);
 315 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 316         dstbuf = opt->dst1;
 317 #endif
 318
 319         if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) {
 320                 skb->transport_header += extlen;
 321                 opt = IP6CB(skb);
 322 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 323                 opt->nhoff = dstbuf;
 324 #else
 325                 opt->nhoff = opt->dst1;
 326 #endif
 327                 return 1;
 328         }
 329
 330         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 331         return -1;
 332 }
 333
 334 static void seg6_update_csum(struct sk_buff *skb)
 335 {
 336         struct ipv6_sr_hdr *hdr;
 337         struct in6_addr *addr;
 338         __be32 from, to;
 339
 340         /* srh is at transport offset and seg_left is already decremented
 341          * but daddr is not yet updated with next segment
 342          */
 343
 344         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 345         addr = hdr->segments + hdr->segments_left;
 346
 347         hdr->segments_left++;
 348         from = *(__be32 *)hdr;
 349
 350         hdr->segments_left--;
 351         to = *(__be32 *)hdr;
 352
 353         /* update skb csum with diff resulting from seg_left decrement */
 354
 355         update_csum_diff4(skb, from, to);
 356
 357         /* compute csum diff between current and next segment and update */
 358
 359         update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr),
 360                            (__be32 *)addr);
 361 }
 362
 363 static int ipv6_srh_rcv(struct sk_buff *skb)
 364 {
 365         struct inet6_skb_parm *opt = IP6CB(skb);
 366         struct net *net = dev_net(skb->dev);
 367         struct ipv6_sr_hdr *hdr;
 368         struct inet6_dev *idev;
 369         struct in6_addr *addr;
 370         int accept_seg6;
 371
 372         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 373
 374         idev = __in6_dev_get(skb->dev);
 375
 376         accept_seg6 = net->ipv6.devconf_all->seg6_enabled;
 377         if (accept_seg6 > idev->cnf.seg6_enabled)
 378                 accept_seg6 = idev->cnf.seg6_enabled;
 379
 380         if (!accept_seg6) {
 381                 kfree_skb(skb);
 382                 return -1;
 383         }
 384
 385 #ifdef CONFIG_IPV6_SEG6_HMAC
 386         if (!seg6_hmac_validate_skb(skb)) {
 387                 kfree_skb(skb);
 388                 return -1;
 389         }
 390 #endif
 391
 392 looped_back:
 393         if (hdr->segments_left == 0) {
 394                 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) {
 395                         int offset = (hdr->hdrlen + 1) << 3;
 396
 397                         skb_postpull_rcsum(skb, skb_network_header(skb),
 398                                            skb_network_header_len(skb));
 399
 400                         if (!pskb_pull(skb, offset)) {
 401                                 kfree_skb(skb);
 402                                 return -1;
 403                         }
 404                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 405                                            offset);
 406
 407                         skb_reset_network_header(skb);
 408                         skb_reset_transport_header(skb);
 409                         skb->encapsulation = 0;
 410                         if (hdr->nexthdr == NEXTHDR_IPV4)
 411                                 skb->protocol = htons(ETH_P_IP);
 412                         __skb_tunnel_rx(skb, skb->dev, net);
 413
 414                         netif_rx(skb);
 415                         return -1;
 416                 }
 417
 418                 opt->srcrt = skb_network_header_len(skb);
 419                 opt->lastopt = opt->srcrt;
 420                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 421                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 422
 423                 return 1;
 424         }
 425
 426         if (hdr->segments_left >= (hdr->hdrlen >> 1)) {
 427                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 428                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 429                                   ((&hdr->segments_left) -
 430                                    skb_network_header(skb)));
 431                 return -1;
 432         }
 433
 434         if (skb_cloned(skb)) {
 435                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 436                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 437                                         IPSTATS_MIB_OUTDISCARDS);
 438                         kfree_skb(skb);
 439                         return -1;
 440                 }
 441         }
 442
 443         hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb);
 444
 445         hdr->segments_left--;
 446         addr = hdr->segments + hdr->segments_left;
 447
 448         skb_push(skb, sizeof(struct ipv6hdr));
 449
 450         if (skb->ip_summed == CHECKSUM_COMPLETE)
 451                 seg6_update_csum(skb);
 452
 453         ipv6_hdr(skb)->daddr = *addr;
 454
 455         skb_dst_drop(skb);
 456
 457         ip6_route_input(skb);
 458
 459         if (skb_dst(skb)->error) {
 460                 dst_input(skb);
 461                 return -1;
 462         }
 463
 464         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 465                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 466                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 467                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 468                                     ICMPV6_EXC_HOPLIMIT, 0);
 469                         kfree_skb(skb);
 470                         return -1;
 471                 }
 472                 ipv6_hdr(skb)->hop_limit--;
 473
 474                 skb_pull(skb, sizeof(struct ipv6hdr));
 475                 goto looped_back;
 476         }
 477
 478         dst_input(skb);
 479
 480         return -1;
 481 }
 482
 483 static int ipv6_rpl_srh_rcv(struct sk_buff *skb)
 484 {
 485         struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr;
 486         struct inet6_skb_parm *opt = IP6CB(skb);
 487         struct net *net = dev_net(skb->dev);
 488         struct inet6_dev *idev;
 489         struct ipv6hdr *oldhdr;
 490         struct in6_addr addr;
 491         unsigned char *buf;
 492         int accept_rpl_seg;
 493         int i, err;
 494         u64 n = 0;
 495         u32 r;
 496
 497         idev = __in6_dev_get(skb->dev);
 498
 499         accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled;
 500         if (accept_rpl_seg > idev->cnf.rpl_seg_enabled)
 501                 accept_rpl_seg = idev->cnf.rpl_seg_enabled;
 502
 503         if (!accept_rpl_seg) {
 504                 kfree_skb(skb);
 505                 return -1;
 506         }
 507
 508 looped_back:
 509         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 510
 511         if (hdr->segments_left == 0) {
 512                 if (hdr->nexthdr == NEXTHDR_IPV6) {
 513                         int offset = (hdr->hdrlen + 1) << 3;
 514
 515                         skb_postpull_rcsum(skb, skb_network_header(skb),
 516                                            skb_network_header_len(skb));
 517
 518                         if (!pskb_pull(skb, offset)) {
 519                                 kfree_skb(skb);
 520                                 return -1;
 521                         }
 522                         skb_postpull_rcsum(skb, skb_transport_header(skb),
 523                                            offset);
 524
 525                         skb_reset_network_header(skb);
 526                         skb_reset_transport_header(skb);
 527                         skb->encapsulation = 0;
 528
 529                         __skb_tunnel_rx(skb, skb->dev, net);
 530
 531                         netif_rx(skb);
 532                         return -1;
 533                 }
 534
 535                 opt->srcrt = skb_network_header_len(skb);
 536                 opt->lastopt = opt->srcrt;
 537                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 538                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 539
 540                 return 1;
 541         }
 542
 543         if (!pskb_may_pull(skb, sizeof(*hdr))) {
 544                 kfree_skb(skb);
 545                 return -1;
 546         }
 547
 548         n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre);
 549         r = do_div(n, (16 - hdr->cmpri));
 550         /* checks if calculation was without remainder and n fits into
 551          * unsigned char which is segments_left field. Should not be
 552          * higher than that.
 553          */
 554         if (r || (n + 1) > 255) {
 555                 kfree_skb(skb);
 556                 return -1;
 557         }
 558
 559         if (hdr->segments_left > n + 1) {
 560                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 561                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 562                                   ((&hdr->segments_left) -
 563                                    skb_network_header(skb)));
 564                 return -1;
 565         }
 566
 567         if (skb_cloned(skb)) {
 568                 if (pskb_expand_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE, 0,
 569                                      GFP_ATOMIC)) {
 570                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 571                                         IPSTATS_MIB_OUTDISCARDS);
 572                         kfree_skb(skb);
 573                         return -1;
 574                 }
 575         } else {
 576                 err = skb_cow_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE);
 577                 if (unlikely(err)) {
 578                         kfree_skb(skb);
 579                         return -1;
 580                 }
 581         }
 582
 583         hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb);
 584
 585         if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
 586                                                   hdr->cmpre))) {
 587                 kfree_skb(skb);
 588                 return -1;
 589         }
 590
 591         hdr->segments_left--;
 592         i = n - hdr->segments_left;
 593
 594         buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
 595         if (unlikely(!buf)) {
 596                 kfree_skb(skb);
 597                 return -1;
 598         }
 599
 600         ohdr = (struct ipv6_rpl_sr_hdr *)buf;
 601         ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 602         chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 603
 604         if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
 605             (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
 606                 kfree_skb(skb);
 607                 kfree(buf);
 608                 return -1;
 609         }
 610
 611         err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
 612         if (err) {
 613                 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
 614                 kfree_skb(skb);
 615                 kfree(buf);
 616                 return -1;
 617         }
 618
 619         addr = ipv6_hdr(skb)->daddr;
 620         ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
 621         ohdr->rpl_segaddr[i] = addr;
 622
 623         ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
 624
 625         oldhdr = ipv6_hdr(skb);
 626
 627         skb_pull(skb, ((hdr->hdrlen + 1) << 3));
 628         skb_postpull_rcsum(skb, oldhdr,
 629                            sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
 630         skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
 631         skb_reset_network_header(skb);
 632         skb_mac_header_rebuild(skb);
 633         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 634
 635         memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
 636         memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
 637
 638         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 639         skb_postpush_rcsum(skb, ipv6_hdr(skb),
 640                            sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
 641
 642         kfree(buf);
 643
 644         skb_dst_drop(skb);
 645
 646         ip6_route_input(skb);
 647
 648         if (skb_dst(skb)->error) {
 649                 dst_input(skb);
 650                 return -1;
 651         }
 652
 653         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 654                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 655                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 656                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 657                                     ICMPV6_EXC_HOPLIMIT, 0);
 658                         kfree_skb(skb);
 659                         return -1;
 660                 }
 661                 ipv6_hdr(skb)->hop_limit--;
 662
 663                 skb_pull(skb, sizeof(struct ipv6hdr));
 664                 goto looped_back;
 665         }
 666
 667         dst_input(skb);
 668
 669         return -1;
 670 }
 671
 672 /********************************
 673   Routing header.
 674  ********************************/
 675
 676 /* called with rcu_read_lock() */
 677 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 678 {
 679         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 680         struct inet6_skb_parm *opt = IP6CB(skb);
 681         struct in6_addr *addr = NULL;
 682         struct in6_addr daddr;
 683         int n, i;
 684         struct ipv6_rt_hdr *hdr;
 685         struct rt0_hdr *rthdr;
 686         struct net *net = dev_net(skb->dev);
 687         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 688
 689         idev = __in6_dev_get(skb->dev);
 690         if (idev && accept_source_route > idev->cnf.accept_source_route)
 691                 accept_source_route = idev->cnf.accept_source_route;
 692
 693         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 694             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 695                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 696                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 697                 kfree_skb(skb);
 698                 return -1;
 699         }
 700
 701         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 702
 703         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 704             skb->pkt_type != PACKET_HOST) {
 705                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 706                 kfree_skb(skb);
 707                 return -1;
 708         }
 709
 710         switch (hdr->type) {
 711         case IPV6_SRCRT_TYPE_4:
 712                 /* segment routing */
 713                 return ipv6_srh_rcv(skb);
 714         case IPV6_SRCRT_TYPE_3:
 715                 /* rpl segment routing */
 716                 return ipv6_rpl_srh_rcv(skb);
 717         default:
 718                 break;
 719         }
 720
 721 looped_back:
 722         if (hdr->segments_left == 0) {
 723                 switch (hdr->type) {
 724 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 725                 case IPV6_SRCRT_TYPE_2:
 726                         /* Silently discard type 2 header unless it was
 727                          * processed by own
 728                          */
 729                         if (!addr) {
 730                                 __IP6_INC_STATS(net, idev,
 731                                                 IPSTATS_MIB_INADDRERRORS);
 732                                 kfree_skb(skb);
 733                                 return -1;
 734                         }
 735                         break;
 736 #endif
 737                 default:
 738                         break;
 739                 }
 740
 741                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 742                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 743                 opt->dst0 = opt->dst1;
 744                 opt->dst1 = 0;
 745                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 746                 return 1;
 747         }
 748
 749         switch (hdr->type) {
 750 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 751         case IPV6_SRCRT_TYPE_2:
 752                 if (accept_source_route < 0)
 753                         goto unknown_rh;
 754                 /* Silently discard invalid RTH type 2 */
 755                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 756                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 757                         kfree_skb(skb);
 758                         return -1;
 759                 }
 760                 break;
 761 #endif
 762         default:
 763                 goto unknown_rh;
 764         }
 765
 766         /*
 767          *      This is the routing header forwarding algorithm from
 768          *      RFC 2460, page 16.
 769          */
 770
 771         n = hdr->hdrlen >> 1;
 772
 773         if (hdr->segments_left > n) {
 774                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 775                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 776                                   ((&hdr->segments_left) -
 777                                    skb_network_header(skb)));
 778                 return -1;
 779         }
 780
 781         /* We are about to mangle packet header. Be careful!
 782            Do not damage packets queued somewhere.
 783          */
 784         if (skb_cloned(skb)) {
 785                 /* the copy is a forwarded packet */
 786                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 787                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 788                                         IPSTATS_MIB_OUTDISCARDS);
 789                         kfree_skb(skb);
 790                         return -1;
 791                 }
 792                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 793         }
 794
 795         if (skb->ip_summed == CHECKSUM_COMPLETE)
 796                 skb->ip_summed = CHECKSUM_NONE;
 797
 798         i = n - --hdr->segments_left;
 799
 800         rthdr = (struct rt0_hdr *) hdr;
 801         addr = rthdr->addr;
 802         addr += i - 1;
 803
 804         switch (hdr->type) {
 805 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 806         case IPV6_SRCRT_TYPE_2:
 807                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 808                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 809                                      IPPROTO_ROUTING) < 0) {
 810                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 811                         kfree_skb(skb);
 812                         return -1;
 813                 }
 814                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 815                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 816                         kfree_skb(skb);
 817                         return -1;
 818                 }
 819                 break;
 820 #endif
 821         default:
 822                 break;
 823         }
 824
 825         if (ipv6_addr_is_multicast(addr)) {
 826                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 827                 kfree_skb(skb);
 828                 return -1;
 829         }
 830
 831         daddr = *addr;
 832         *addr = ipv6_hdr(skb)->daddr;
 833         ipv6_hdr(skb)->daddr = daddr;
 834
 835         skb_dst_drop(skb);
 836         ip6_route_input(skb);
 837         if (skb_dst(skb)->error) {
 838                 skb_push(skb, skb->data - skb_network_header(skb));
 839                 dst_input(skb);
 840                 return -1;
 841         }
 842
 843         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 844                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 845                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 846                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 847                                     0);
 848                         kfree_skb(skb);
 849                         return -1;
 850                 }
 851                 ipv6_hdr(skb)->hop_limit--;
 852                 goto looped_back;
 853         }
 854
 855         skb_push(skb, skb->data - skb_network_header(skb));
 856         dst_input(skb);
 857         return -1;
 858
 859 unknown_rh:
 860         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 861         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 862                           (&hdr->type) - skb_network_header(skb));
 863         return -1;
 864 }
 865
 866 static const struct inet6_protocol rthdr_protocol = {
 867         .handler        =       ipv6_rthdr_rcv,
 868         .flags          =       INET6_PROTO_NOPOLICY,
 869 };
 870
 871 static const struct inet6_protocol destopt_protocol = {
 872         .handler        =       ipv6_destopt_rcv,
 873         .flags          =       INET6_PROTO_NOPOLICY,
 874 };
 875
 876 static const struct inet6_protocol nodata_protocol = {
 877         .handler        =       dst_discard,
 878         .flags          =       INET6_PROTO_NOPOLICY,
 879 };
 880
 881 int __init ipv6_exthdrs_init(void)
 882 {
 883         int ret;
 884
 885         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 886         if (ret)
 887                 goto out;
 888
 889         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 890         if (ret)
 891                 goto out_rthdr;
 892
 893         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 894         if (ret)
 895                 goto out_destopt;
 896
 897 out:
 898         return ret;
 899 out_destopt:
 900         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 901 out_rthdr:
 902         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 903         goto out;
 904 };
 905
 906 void ipv6_exthdrs_exit(void)
 907 {
 908         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 909         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 910         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 911 }
 912
 913 /**********************************
 914   Hop-by-hop options.
 915  **********************************/
 916
 917 /*
 918  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 919  */
 920 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 921 {
 922         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 923 }
 924
 925 /* Router Alert as of RFC 2711 */
 926
 927 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 928 {
 929         const unsigned char *nh = skb_network_header(skb);
 930
 931         if (nh[optoff + 1] == 2) {
 932                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 933                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 934                 return true;
 935         }
 936         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 937                             nh[optoff + 1]);
 938         kfree_skb(skb);
 939         return false;
 940 }
 941
 942 /* IOAM */
 943
 944 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
 945 {
 946         struct ioam6_trace_hdr *trace;
 947         struct ioam6_namespace *ns;
 948         struct ioam6_hdr *hdr;
 949
 950         /* Bad alignment (must be 4n-aligned) */
 951         if (optoff & 3)
 952                 goto drop;
 953
 954         /* Ignore if IOAM is not enabled on ingress */
 955         if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
 956                 goto ignore;
 957
 958         /* Truncated Option header */
 959         hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
 960         if (hdr->opt_len < 2)
 961                 goto drop;
 962
 963         switch (hdr->type) {
 964         case IOAM6_TYPE_PREALLOC:
 965                 /* Truncated Pre-allocated Trace header */
 966                 if (hdr->opt_len < 2 + sizeof(*trace))
 967                         goto drop;
 968
 969                 /* Malformed Pre-allocated Trace header */
 970                 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
 971                 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
 972                         goto drop;
 973
 974                 /* Ignore if the IOAM namespace is unknown */
 975                 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
 976                 if (!ns)
 977                         goto ignore;
 978
 979                 if (!skb_valid_dst(skb))
 980                         ip6_route_input(skb);
 981
 982                 ioam6_fill_trace_data(skb, ns, trace);
 983                 break;
 984         default:
 985                 break;
 986         }
 987
 988 ignore:
 989         return true;
 990
 991 drop:
 992         kfree_skb(skb);
 993         return false;
 994 }
 995
 996 /* Jumbo payload */
 997
 998 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 999 {
1000         const unsigned char *nh = skb_network_header(skb);
1001         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
1002         struct net *net = ipv6_skb_net(skb);
1003         u32 pkt_len;
1004
1005         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
1006                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
1007                                     nh[optoff+1]);
1008                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1009                 goto drop;
1010         }
1011
1012         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1013         if (pkt_len <= IPV6_MAXPLEN) {
1014                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1015                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
1016                 return false;
1017         }
1018         if (ipv6_hdr(skb)->payload_len) {
1019                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1020                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
1021                 return false;
1022         }
1023
1024         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1025                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
1026                 goto drop;
1027         }
1028
1029         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1030                 goto drop;
1031
1032         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1033         return true;
1034
1035 drop:
1036         kfree_skb(skb);
1037         return false;
1038 }
1039
1040 /* CALIPSO RFC 5570 */
1041
1042 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1043 {
1044         const unsigned char *nh = skb_network_header(skb);
1045
1046         if (nh[optoff + 1] < 8)
1047                 goto drop;
1048
1049         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1050                 goto drop;
1051
1052         if (!calipso_validate(skb, nh + optoff))
1053                 goto drop;
1054
1055         return true;
1056
1057 drop:
1058         kfree_skb(skb);
1059         return false;
1060 }
1061
1062 int ipv6_parse_hopopts(struct sk_buff *skb)
1063 {
1064         struct inet6_skb_parm *opt = IP6CB(skb);
1065         struct net *net = dev_net(skb->dev);
1066         int extlen;
1067
1068         /*
1069          * skb_network_header(skb) is equal to skb->data, and
1070          * skb_network_header_len(skb) is always equal to
1071          * sizeof(struct ipv6hdr) by definition of
1072          * hop-by-hop options.
1073          */
1074         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1075             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1076                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1077 fail_and_free:
1078                 kfree_skb(skb);
1079                 return -1;
1080         }
1081
1082         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1083         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1084                 goto fail_and_free;
1085
1086         opt->flags |= IP6SKB_HOPBYHOP;
1087         if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1088                 skb->transport_header += extlen;
1089                 opt = IP6CB(skb);
1090                 opt->nhoff = sizeof(struct ipv6hdr);
1091                 return 1;
1092         }
1093         return -1;
1094 }
1095
1096 /*
1097  *      Creating outbound headers.
1098  *
1099  *      "build" functions work when skb is filled from head to tail (datagram)
1100  *      "push"  functions work when headers are added from tail to head (tcp)
1101  *
1102  *      In both cases we assume, that caller reserved enough room
1103  *      for headers.
1104  */
1105
1106 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1107                              struct ipv6_rt_hdr *opt,
1108                              struct in6_addr **addr_p, struct in6_addr *saddr)
1109 {
1110         struct rt0_hdr *phdr, *ihdr;
1111         int hops;
1112
1113         ihdr = (struct rt0_hdr *) opt;
1114
1115         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1116         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1117
1118         hops = ihdr->rt_hdr.hdrlen >> 1;
1119
1120         if (hops > 1)
1121                 memcpy(phdr->addr, ihdr->addr + 1,
1122                        (hops - 1) * sizeof(struct in6_addr));
1123
1124         phdr->addr[hops - 1] = **addr_p;
1125         *addr_p = ihdr->addr;
1126
1127         phdr->rt_hdr.nexthdr = *proto;
1128         *proto = NEXTHDR_ROUTING;
1129 }
1130
1131 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1132                              struct ipv6_rt_hdr *opt,
1133                              struct in6_addr **addr_p, struct in6_addr *saddr)
1134 {
1135         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1136         int plen, hops;
1137
1138         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1139         plen = (sr_ihdr->hdrlen + 1) << 3;
1140
1141         sr_phdr = skb_push(skb, plen);
1142         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1143
1144         hops = sr_ihdr->first_segment + 1;
1145         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1146                (hops - 1) * sizeof(struct in6_addr));
1147
1148         sr_phdr->segments[0] = **addr_p;
1149         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1150
1151         if (sr_ihdr->hdrlen > hops * 2) {
1152                 int tlvs_offset, tlvs_length;
1153
1154                 tlvs_offset = (1 + hops * 2) << 3;
1155                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1156                 memcpy((char *)sr_phdr + tlvs_offset,
1157                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1158         }
1159
1160 #ifdef CONFIG_IPV6_SEG6_HMAC
1161         if (sr_has_hmac(sr_phdr)) {
1162                 struct net *net = NULL;
1163
1164                 if (skb->dev)
1165                         net = dev_net(skb->dev);
1166                 else if (skb->sk)
1167                         net = sock_net(skb->sk);
1168
1169                 WARN_ON(!net);
1170
1171                 if (net)
1172                         seg6_push_hmac(net, saddr, sr_phdr);
1173         }
1174 #endif
1175
1176         sr_phdr->nexthdr = *proto;
1177         *proto = NEXTHDR_ROUTING;
1178 }
1179
1180 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1181                             struct ipv6_rt_hdr *opt,
1182                             struct in6_addr **addr_p, struct in6_addr *saddr)
1183 {
1184         switch (opt->type) {
1185         case IPV6_SRCRT_TYPE_0:
1186         case IPV6_SRCRT_STRICT:
1187         case IPV6_SRCRT_TYPE_2:
1188                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1189                 break;
1190         case IPV6_SRCRT_TYPE_4:
1191                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1192                 break;
1193         default:
1194                 break;
1195         }
1196 }
1197
1198 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1199 {
1200         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1201
1202         memcpy(h, opt, ipv6_optlen(opt));
1203         h->nexthdr = *proto;
1204         *proto = type;
1205 }
1206
1207 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1208                           u8 *proto,
1209                           struct in6_addr **daddr, struct in6_addr *saddr)
1210 {
1211         if (opt->srcrt) {
1212                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1213                 /*
1214                  * IPV6_RTHDRDSTOPTS is ignored
1215                  * unless IPV6_RTHDR is set (RFC3542).
1216                  */
1217                 if (opt->dst0opt)
1218                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1219         }
1220         if (opt->hopopt)
1221                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1222 }
1223
1224 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1225 {
1226         if (opt->dst1opt)
1227                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1228 }
1229 EXPORT_SYMBOL(ipv6_push_frag_opts);
1230
1231 struct ipv6_txoptions *
1232 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1233 {
1234         struct ipv6_txoptions *opt2;
1235
1236         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1237         if (opt2) {
1238                 long dif = (char *)opt2 - (char *)opt;
1239                 memcpy(opt2, opt, opt->tot_len);
1240                 if (opt2->hopopt)
1241                         *((char **)&opt2->hopopt) += dif;
1242                 if (opt2->dst0opt)
1243                         *((char **)&opt2->dst0opt) += dif;
1244                 if (opt2->dst1opt)
1245                         *((char **)&opt2->dst1opt) += dif;
1246                 if (opt2->srcrt)
1247                         *((char **)&opt2->srcrt) += dif;
1248                 refcount_set(&opt2->refcnt, 1);
1249         }
1250         return opt2;
1251 }
1252 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1253
1254 static void ipv6_renew_option(int renewtype,
1255                               struct ipv6_opt_hdr **dest,
1256                               struct ipv6_opt_hdr *old,
1257                               struct ipv6_opt_hdr *new,
1258                               int newtype, char **p)
1259 {
1260         struct ipv6_opt_hdr *src;
1261
1262         src = (renewtype == newtype ? new : old);
1263         if (!src)
1264                 return;
1265
1266         memcpy(*p, src, ipv6_optlen(src));
1267         *dest = (struct ipv6_opt_hdr *)*p;
1268         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1269 }
1270
1271 /**
1272  * ipv6_renew_options - replace a specific ext hdr with a new one.
1273  *
1274  * @sk: sock from which to allocate memory
1275  * @opt: original options
1276  * @newtype: option type to replace in @opt
1277  * @newopt: new option of type @newtype to replace (user-mem)
1278  *
1279  * Returns a new set of options which is a copy of @opt with the
1280  * option type @newtype replaced with @newopt.
1281  *
1282  * @opt may be NULL, in which case a new set of options is returned
1283  * containing just @newopt.
1284  *
1285  * @newopt may be NULL, in which case the specified option type is
1286  * not copied into the new set of options.
1287  *
1288  * The new set of options is allocated from the socket option memory
1289  * buffer of @sk.
1290  */
1291 struct ipv6_txoptions *
1292 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1293                    int newtype, struct ipv6_opt_hdr *newopt)
1294 {
1295         int tot_len = 0;
1296         char *p;
1297         struct ipv6_txoptions *opt2;
1298
1299         if (opt) {
1300                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1301                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1302                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1303                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1304                 if (newtype != IPV6_RTHDR && opt->srcrt)
1305                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1306                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1307                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1308         }
1309
1310         if (newopt)
1311                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1312
1313         if (!tot_len)
1314                 return NULL;
1315
1316         tot_len += sizeof(*opt2);
1317         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1318         if (!opt2)
1319                 return ERR_PTR(-ENOBUFS);
1320
1321         memset(opt2, 0, tot_len);
1322         refcount_set(&opt2->refcnt, 1);
1323         opt2->tot_len = tot_len;
1324         p = (char *)(opt2 + 1);
1325
1326         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1327                           (opt ? opt->hopopt : NULL),
1328                           newopt, newtype, &p);
1329         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1330                           (opt ? opt->dst0opt : NULL),
1331                           newopt, newtype, &p);
1332         ipv6_renew_option(IPV6_RTHDR,
1333                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1334                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1335                           newopt, newtype, &p);
1336         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1337                           (opt ? opt->dst1opt : NULL),
1338                           newopt, newtype, &p);
1339
1340         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1341                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1342                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1343         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1344
1345         return opt2;
1346 }
1347
1348 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1349                                           struct ipv6_txoptions *opt)
1350 {
1351         /*
1352          * ignore the dest before srcrt unless srcrt is being included.
1353          * --yoshfuji
1354          */
1355         if (opt && opt->dst0opt && !opt->srcrt) {
1356                 if (opt_space != opt) {
1357                         memcpy(opt_space, opt, sizeof(*opt_space));
1358                         opt = opt_space;
1359                 }
1360                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1361                 opt->dst0opt = NULL;
1362         }
1363
1364         return opt;
1365 }
1366 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1367
1368 /**
1369  * fl6_update_dst - update flowi destination address with info given
1370  *                  by srcrt option, if any.
1371  *
1372  * @fl6: flowi6 for which daddr is to be updated
1373  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1374  * @orig: copy of original daddr address if modified
1375  *
1376  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1377  * and initial value of fl6->daddr set in orig
1378  */
1379 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1380                                 const struct ipv6_txoptions *opt,
1381                                 struct in6_addr *orig)
1382 {
1383         if (!opt || !opt->srcrt)
1384                 return NULL;
1385
1386         *orig = fl6->daddr;
1387
1388         switch (opt->srcrt->type) {
1389         case IPV6_SRCRT_TYPE_0:
1390         case IPV6_SRCRT_STRICT:
1391         case IPV6_SRCRT_TYPE_2:
1392                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1393                 break;
1394         case IPV6_SRCRT_TYPE_4:
1395         {
1396                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1397
1398                 fl6->daddr = srh->segments[srh->segments_left];
1399                 break;
1400         }
1401         default:
1402                 return NULL;
1403         }
1404
1405         return orig;
1406 }
1407 EXPORT_SYMBOL_GPL(fl6_update_dst);