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         if (idev && accept_source_route > idev->cnf.accept_source_route)
 690                 accept_source_route = idev->cnf.accept_source_route;
 691
 692         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 693             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 694                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 695                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 696                 kfree_skb(skb);
 697                 return -1;
 698         }
 699
 700         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 701
 702         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 703             skb->pkt_type != PACKET_HOST) {
 704                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 705                 kfree_skb(skb);
 706                 return -1;
 707         }
 708
 709         switch (hdr->type) {
 710         case IPV6_SRCRT_TYPE_4:
 711                 /* segment routing */
 712                 return ipv6_srh_rcv(skb);
 713         case IPV6_SRCRT_TYPE_3:
 714                 /* rpl segment routing */
 715                 return ipv6_rpl_srh_rcv(skb);
 716         default:
 717                 break;
 718         }
 719
 720 looped_back:
 721         if (hdr->segments_left == 0) {
 722                 switch (hdr->type) {
 723 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 724                 case IPV6_SRCRT_TYPE_2:
 725                         /* Silently discard type 2 header unless it was
 726                          * processed by own
 727                          */
 728                         if (!addr) {
 729                                 __IP6_INC_STATS(net, idev,
 730                                                 IPSTATS_MIB_INADDRERRORS);
 731                                 kfree_skb(skb);
 732                                 return -1;
 733                         }
 734                         break;
 735 #endif
 736                 default:
 737                         break;
 738                 }
 739
 740                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 741                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 742                 opt->dst0 = opt->dst1;
 743                 opt->dst1 = 0;
 744                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 745                 return 1;
 746         }
 747
 748         switch (hdr->type) {
 749 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 750         case IPV6_SRCRT_TYPE_2:
 751                 if (accept_source_route < 0)
 752                         goto unknown_rh;
 753                 /* Silently discard invalid RTH type 2 */
 754                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 755                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 756                         kfree_skb(skb);
 757                         return -1;
 758                 }
 759                 break;
 760 #endif
 761         default:
 762                 goto unknown_rh;
 763         }
 764
 765         /*
 766          *      This is the routing header forwarding algorithm from
 767          *      RFC 2460, page 16.
 768          */
 769
 770         n = hdr->hdrlen >> 1;
 771
 772         if (hdr->segments_left > n) {
 773                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 774                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 775                                   ((&hdr->segments_left) -
 776                                    skb_network_header(skb)));
 777                 return -1;
 778         }
 779
 780         /* We are about to mangle packet header. Be careful!
 781            Do not damage packets queued somewhere.
 782          */
 783         if (skb_cloned(skb)) {
 784                 /* the copy is a forwarded packet */
 785                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 786                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 787                                         IPSTATS_MIB_OUTDISCARDS);
 788                         kfree_skb(skb);
 789                         return -1;
 790                 }
 791                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 792         }
 793
 794         if (skb->ip_summed == CHECKSUM_COMPLETE)
 795                 skb->ip_summed = CHECKSUM_NONE;
 796
 797         i = n - --hdr->segments_left;
 798
 799         rthdr = (struct rt0_hdr *) hdr;
 800         addr = rthdr->addr;
 801         addr += i - 1;
 802
 803         switch (hdr->type) {
 804 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 805         case IPV6_SRCRT_TYPE_2:
 806                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 807                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 808                                      IPPROTO_ROUTING) < 0) {
 809                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 810                         kfree_skb(skb);
 811                         return -1;
 812                 }
 813                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 814                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 815                         kfree_skb(skb);
 816                         return -1;
 817                 }
 818                 break;
 819 #endif
 820         default:
 821                 break;
 822         }
 823
 824         if (ipv6_addr_is_multicast(addr)) {
 825                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 826                 kfree_skb(skb);
 827                 return -1;
 828         }
 829
 830         daddr = *addr;
 831         *addr = ipv6_hdr(skb)->daddr;
 832         ipv6_hdr(skb)->daddr = daddr;
 833
 834         skb_dst_drop(skb);
 835         ip6_route_input(skb);
 836         if (skb_dst(skb)->error) {
 837                 skb_push(skb, skb->data - skb_network_header(skb));
 838                 dst_input(skb);
 839                 return -1;
 840         }
 841
 842         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 843                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 844                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 845                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 846                                     0);
 847                         kfree_skb(skb);
 848                         return -1;
 849                 }
 850                 ipv6_hdr(skb)->hop_limit--;
 851                 goto looped_back;
 852         }
 853
 854         skb_push(skb, skb->data - skb_network_header(skb));
 855         dst_input(skb);
 856         return -1;
 857
 858 unknown_rh:
 859         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 860         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 861                           (&hdr->type) - skb_network_header(skb));
 862         return -1;
 863 }
 864
 865 static const struct inet6_protocol rthdr_protocol = {
 866         .handler        =       ipv6_rthdr_rcv,
 867         .flags          =       INET6_PROTO_NOPOLICY,
 868 };
 869
 870 static const struct inet6_protocol destopt_protocol = {
 871         .handler        =       ipv6_destopt_rcv,
 872         .flags          =       INET6_PROTO_NOPOLICY,
 873 };
 874
 875 static const struct inet6_protocol nodata_protocol = {
 876         .handler        =       dst_discard,
 877         .flags          =       INET6_PROTO_NOPOLICY,
 878 };
 879
 880 int __init ipv6_exthdrs_init(void)
 881 {
 882         int ret;
 883
 884         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 885         if (ret)
 886                 goto out;
 887
 888         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 889         if (ret)
 890                 goto out_rthdr;
 891
 892         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 893         if (ret)
 894                 goto out_destopt;
 895
 896 out:
 897         return ret;
 898 out_destopt:
 899         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 900 out_rthdr:
 901         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 902         goto out;
 903 };
 904
 905 void ipv6_exthdrs_exit(void)
 906 {
 907         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 908         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 909         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 910 }
 911
 912 /**********************************
 913   Hop-by-hop options.
 914  **********************************/
 915
 916 /*
 917  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 918  */
 919 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 920 {
 921         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 922 }
 923
 924 /* Router Alert as of RFC 2711 */
 925
 926 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 927 {
 928         const unsigned char *nh = skb_network_header(skb);
 929
 930         if (nh[optoff + 1] == 2) {
 931                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 932                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 933                 return true;
 934         }
 935         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 936                             nh[optoff + 1]);
 937         kfree_skb(skb);
 938         return false;
 939 }
 940
 941 /* IOAM */
 942
 943 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
 944 {
 945         struct ioam6_trace_hdr *trace;
 946         struct ioam6_namespace *ns;
 947         struct ioam6_hdr *hdr;
 948
 949         /* Bad alignment (must be 4n-aligned) */
 950         if (optoff & 3)
 951                 goto drop;
 952
 953         /* Ignore if IOAM is not enabled on ingress */
 954         if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
 955                 goto ignore;
 956
 957         /* Truncated Option header */
 958         hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
 959         if (hdr->opt_len < 2)
 960                 goto drop;
 961
 962         switch (hdr->type) {
 963         case IOAM6_TYPE_PREALLOC:
 964                 /* Truncated Pre-allocated Trace header */
 965                 if (hdr->opt_len < 2 + sizeof(*trace))
 966                         goto drop;
 967
 968                 /* Malformed Pre-allocated Trace header */
 969                 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
 970                 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
 971                         goto drop;
 972
 973                 /* Ignore if the IOAM namespace is unknown */
 974                 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
 975                 if (!ns)
 976                         goto ignore;
 977
 978                 if (!skb_valid_dst(skb))
 979                         ip6_route_input(skb);
 980
 981                 ioam6_fill_trace_data(skb, ns, trace, true);
 982                 break;
 983         default:
 984                 break;
 985         }
 986
 987 ignore:
 988         return true;
 989
 990 drop:
 991         kfree_skb(skb);
 992         return false;
 993 }
 994
 995 /* Jumbo payload */
 996
 997 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 998 {
 999         const unsigned char *nh = skb_network_header(skb);
1000         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
1001         struct net *net = ipv6_skb_net(skb);
1002         u32 pkt_len;
1003
1004         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
1005                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
1006                                     nh[optoff+1]);
1007                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1008                 goto drop;
1009         }
1010
1011         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1012         if (pkt_len <= IPV6_MAXPLEN) {
1013                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1014                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
1015                 return false;
1016         }
1017         if (ipv6_hdr(skb)->payload_len) {
1018                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1019                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
1020                 return false;
1021         }
1022
1023         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1024                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
1025                 goto drop;
1026         }
1027
1028         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1029                 goto drop;
1030
1031         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1032         return true;
1033
1034 drop:
1035         kfree_skb(skb);
1036         return false;
1037 }
1038
1039 /* CALIPSO RFC 5570 */
1040
1041 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1042 {
1043         const unsigned char *nh = skb_network_header(skb);
1044
1045         if (nh[optoff + 1] < 8)
1046                 goto drop;
1047
1048         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1049                 goto drop;
1050
1051         if (!calipso_validate(skb, nh + optoff))
1052                 goto drop;
1053
1054         return true;
1055
1056 drop:
1057         kfree_skb(skb);
1058         return false;
1059 }
1060
1061 int ipv6_parse_hopopts(struct sk_buff *skb)
1062 {
1063         struct inet6_skb_parm *opt = IP6CB(skb);
1064         struct net *net = dev_net(skb->dev);
1065         int extlen;
1066
1067         /*
1068          * skb_network_header(skb) is equal to skb->data, and
1069          * skb_network_header_len(skb) is always equal to
1070          * sizeof(struct ipv6hdr) by definition of
1071          * hop-by-hop options.
1072          */
1073         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1074             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1075                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1076 fail_and_free:
1077                 kfree_skb(skb);
1078                 return -1;
1079         }
1080
1081         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1082         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1083                 goto fail_and_free;
1084
1085         opt->flags |= IP6SKB_HOPBYHOP;
1086         if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1087                 skb->transport_header += extlen;
1088                 opt = IP6CB(skb);
1089                 opt->nhoff = sizeof(struct ipv6hdr);
1090                 return 1;
1091         }
1092         return -1;
1093 }
1094
1095 /*
1096  *      Creating outbound headers.
1097  *
1098  *      "build" functions work when skb is filled from head to tail (datagram)
1099  *      "push"  functions work when headers are added from tail to head (tcp)
1100  *
1101  *      In both cases we assume, that caller reserved enough room
1102  *      for headers.
1103  */
1104
1105 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1106                              struct ipv6_rt_hdr *opt,
1107                              struct in6_addr **addr_p, struct in6_addr *saddr)
1108 {
1109         struct rt0_hdr *phdr, *ihdr;
1110         int hops;
1111
1112         ihdr = (struct rt0_hdr *) opt;
1113
1114         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1115         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1116
1117         hops = ihdr->rt_hdr.hdrlen >> 1;
1118
1119         if (hops > 1)
1120                 memcpy(phdr->addr, ihdr->addr + 1,
1121                        (hops - 1) * sizeof(struct in6_addr));
1122
1123         phdr->addr[hops - 1] = **addr_p;
1124         *addr_p = ihdr->addr;
1125
1126         phdr->rt_hdr.nexthdr = *proto;
1127         *proto = NEXTHDR_ROUTING;
1128 }
1129
1130 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1131                              struct ipv6_rt_hdr *opt,
1132                              struct in6_addr **addr_p, struct in6_addr *saddr)
1133 {
1134         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1135         int plen, hops;
1136
1137         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1138         plen = (sr_ihdr->hdrlen + 1) << 3;
1139
1140         sr_phdr = skb_push(skb, plen);
1141         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1142
1143         hops = sr_ihdr->first_segment + 1;
1144         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1145                (hops - 1) * sizeof(struct in6_addr));
1146
1147         sr_phdr->segments[0] = **addr_p;
1148         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1149
1150         if (sr_ihdr->hdrlen > hops * 2) {
1151                 int tlvs_offset, tlvs_length;
1152
1153                 tlvs_offset = (1 + hops * 2) << 3;
1154                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1155                 memcpy((char *)sr_phdr + tlvs_offset,
1156                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1157         }
1158
1159 #ifdef CONFIG_IPV6_SEG6_HMAC
1160         if (sr_has_hmac(sr_phdr)) {
1161                 struct net *net = NULL;
1162
1163                 if (skb->dev)
1164                         net = dev_net(skb->dev);
1165                 else if (skb->sk)
1166                         net = sock_net(skb->sk);
1167
1168                 WARN_ON(!net);
1169
1170                 if (net)
1171                         seg6_push_hmac(net, saddr, sr_phdr);
1172         }
1173 #endif
1174
1175         sr_phdr->nexthdr = *proto;
1176         *proto = NEXTHDR_ROUTING;
1177 }
1178
1179 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1180                             struct ipv6_rt_hdr *opt,
1181                             struct in6_addr **addr_p, struct in6_addr *saddr)
1182 {
1183         switch (opt->type) {
1184         case IPV6_SRCRT_TYPE_0:
1185         case IPV6_SRCRT_STRICT:
1186         case IPV6_SRCRT_TYPE_2:
1187                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1188                 break;
1189         case IPV6_SRCRT_TYPE_4:
1190                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1191                 break;
1192         default:
1193                 break;
1194         }
1195 }
1196
1197 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1198 {
1199         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1200
1201         memcpy(h, opt, ipv6_optlen(opt));
1202         h->nexthdr = *proto;
1203         *proto = type;
1204 }
1205
1206 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1207                           u8 *proto,
1208                           struct in6_addr **daddr, struct in6_addr *saddr)
1209 {
1210         if (opt->srcrt) {
1211                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1212                 /*
1213                  * IPV6_RTHDRDSTOPTS is ignored
1214                  * unless IPV6_RTHDR is set (RFC3542).
1215                  */
1216                 if (opt->dst0opt)
1217                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1218         }
1219         if (opt->hopopt)
1220                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1221 }
1222
1223 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1224 {
1225         if (opt->dst1opt)
1226                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1227 }
1228 EXPORT_SYMBOL(ipv6_push_frag_opts);
1229
1230 struct ipv6_txoptions *
1231 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1232 {
1233         struct ipv6_txoptions *opt2;
1234
1235         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1236         if (opt2) {
1237                 long dif = (char *)opt2 - (char *)opt;
1238                 memcpy(opt2, opt, opt->tot_len);
1239                 if (opt2->hopopt)
1240                         *((char **)&opt2->hopopt) += dif;
1241                 if (opt2->dst0opt)
1242                         *((char **)&opt2->dst0opt) += dif;
1243                 if (opt2->dst1opt)
1244                         *((char **)&opt2->dst1opt) += dif;
1245                 if (opt2->srcrt)
1246                         *((char **)&opt2->srcrt) += dif;
1247                 refcount_set(&opt2->refcnt, 1);
1248         }
1249         return opt2;
1250 }
1251 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1252
1253 static void ipv6_renew_option(int renewtype,
1254                               struct ipv6_opt_hdr **dest,
1255                               struct ipv6_opt_hdr *old,
1256                               struct ipv6_opt_hdr *new,
1257                               int newtype, char **p)
1258 {
1259         struct ipv6_opt_hdr *src;
1260
1261         src = (renewtype == newtype ? new : old);
1262         if (!src)
1263                 return;
1264
1265         memcpy(*p, src, ipv6_optlen(src));
1266         *dest = (struct ipv6_opt_hdr *)*p;
1267         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1268 }
1269
1270 /**
1271  * ipv6_renew_options - replace a specific ext hdr with a new one.
1272  *
1273  * @sk: sock from which to allocate memory
1274  * @opt: original options
1275  * @newtype: option type to replace in @opt
1276  * @newopt: new option of type @newtype to replace (user-mem)
1277  *
1278  * Returns a new set of options which is a copy of @opt with the
1279  * option type @newtype replaced with @newopt.
1280  *
1281  * @opt may be NULL, in which case a new set of options is returned
1282  * containing just @newopt.
1283  *
1284  * @newopt may be NULL, in which case the specified option type is
1285  * not copied into the new set of options.
1286  *
1287  * The new set of options is allocated from the socket option memory
1288  * buffer of @sk.
1289  */
1290 struct ipv6_txoptions *
1291 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1292                    int newtype, struct ipv6_opt_hdr *newopt)
1293 {
1294         int tot_len = 0;
1295         char *p;
1296         struct ipv6_txoptions *opt2;
1297
1298         if (opt) {
1299                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1300                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1301                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1302                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1303                 if (newtype != IPV6_RTHDR && opt->srcrt)
1304                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1305                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1306                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1307         }
1308
1309         if (newopt)
1310                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1311
1312         if (!tot_len)
1313                 return NULL;
1314
1315         tot_len += sizeof(*opt2);
1316         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1317         if (!opt2)
1318                 return ERR_PTR(-ENOBUFS);
1319
1320         memset(opt2, 0, tot_len);
1321         refcount_set(&opt2->refcnt, 1);
1322         opt2->tot_len = tot_len;
1323         p = (char *)(opt2 + 1);
1324
1325         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1326                           (opt ? opt->hopopt : NULL),
1327                           newopt, newtype, &p);
1328         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1329                           (opt ? opt->dst0opt : NULL),
1330                           newopt, newtype, &p);
1331         ipv6_renew_option(IPV6_RTHDR,
1332                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1333                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1334                           newopt, newtype, &p);
1335         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1336                           (opt ? opt->dst1opt : NULL),
1337                           newopt, newtype, &p);
1338
1339         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1340                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1341                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1342         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1343
1344         return opt2;
1345 }
1346
1347 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1348                                           struct ipv6_txoptions *opt)
1349 {
1350         /*
1351          * ignore the dest before srcrt unless srcrt is being included.
1352          * --yoshfuji
1353          */
1354         if (opt && opt->dst0opt && !opt->srcrt) {
1355                 if (opt_space != opt) {
1356                         memcpy(opt_space, opt, sizeof(*opt_space));
1357                         opt = opt_space;
1358                 }
1359                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1360                 opt->dst0opt = NULL;
1361         }
1362
1363         return opt;
1364 }
1365 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1366
1367 /**
1368  * fl6_update_dst - update flowi destination address with info given
1369  *                  by srcrt option, if any.
1370  *
1371  * @fl6: flowi6 for which daddr is to be updated
1372  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1373  * @orig: copy of original daddr address if modified
1374  *
1375  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1376  * and initial value of fl6->daddr set in orig
1377  */
1378 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1379                                 const struct ipv6_txoptions *opt,
1380                                 struct in6_addr *orig)
1381 {
1382         if (!opt || !opt->srcrt)
1383                 return NULL;
1384
1385         *orig = fl6->daddr;
1386
1387         switch (opt->srcrt->type) {
1388         case IPV6_SRCRT_TYPE_0:
1389         case IPV6_SRCRT_STRICT:
1390         case IPV6_SRCRT_TYPE_2:
1391                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1392                 break;
1393         case IPV6_SRCRT_TYPE_4:
1394         {
1395                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1396
1397                 fl6->daddr = srh->segments[srh->segments_left];
1398                 break;
1399         }
1400         default:
1401                 return NULL;
1402         }
1403
1404         return orig;
1405 }
1406 EXPORT_SYMBOL_GPL(fl6_update_dst);