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 (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri,
 568                                                   hdr->cmpre))) {
 569                 kfree_skb(skb);
 570                 return -1;
 571         }
 572
 573         hdr->segments_left--;
 574         i = n - hdr->segments_left;
 575
 576         buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC);
 577         if (unlikely(!buf)) {
 578                 kfree_skb(skb);
 579                 return -1;
 580         }
 581
 582         ohdr = (struct ipv6_rpl_sr_hdr *)buf;
 583         ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n);
 584         chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3));
 585
 586         if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) ||
 587             (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) {
 588                 kfree_skb(skb);
 589                 kfree(buf);
 590                 return -1;
 591         }
 592
 593         err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1);
 594         if (err) {
 595                 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0);
 596                 kfree_skb(skb);
 597                 kfree(buf);
 598                 return -1;
 599         }
 600
 601         addr = ipv6_hdr(skb)->daddr;
 602         ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i];
 603         ohdr->rpl_segaddr[i] = addr;
 604
 605         ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n);
 606
 607         oldhdr = ipv6_hdr(skb);
 608
 609         skb_pull(skb, ((hdr->hdrlen + 1) << 3));
 610         skb_postpull_rcsum(skb, oldhdr,
 611                            sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3));
 612         if (unlikely(!hdr->segments_left)) {
 613                 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0,
 614                                      GFP_ATOMIC)) {
 615                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS);
 616                         kfree_skb(skb);
 617                         kfree(buf);
 618                         return -1;
 619                 }
 620
 621                 oldhdr = ipv6_hdr(skb);
 622         }
 623         skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr));
 624         skb_reset_network_header(skb);
 625         skb_mac_header_rebuild(skb);
 626         skb_set_transport_header(skb, sizeof(struct ipv6hdr));
 627
 628         memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr));
 629         memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3);
 630
 631         ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr));
 632         skb_postpush_rcsum(skb, ipv6_hdr(skb),
 633                            sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3));
 634
 635         kfree(buf);
 636
 637         skb_dst_drop(skb);
 638
 639         ip6_route_input(skb);
 640
 641         if (skb_dst(skb)->error) {
 642                 dst_input(skb);
 643                 return -1;
 644         }
 645
 646         if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) {
 647                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 648                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 649                         icmpv6_send(skb, ICMPV6_TIME_EXCEED,
 650                                     ICMPV6_EXC_HOPLIMIT, 0);
 651                         kfree_skb(skb);
 652                         return -1;
 653                 }
 654                 ipv6_hdr(skb)->hop_limit--;
 655
 656                 skb_pull(skb, sizeof(struct ipv6hdr));
 657                 goto looped_back;
 658         }
 659
 660         dst_input(skb);
 661
 662         return -1;
 663 }
 664
 665 /********************************
 666   Routing header.
 667  ********************************/
 668
 669 /* called with rcu_read_lock() */
 670 static int ipv6_rthdr_rcv(struct sk_buff *skb)
 671 {
 672         struct inet6_dev *idev = __in6_dev_get(skb->dev);
 673         struct inet6_skb_parm *opt = IP6CB(skb);
 674         struct in6_addr *addr = NULL;
 675         struct in6_addr daddr;
 676         int n, i;
 677         struct ipv6_rt_hdr *hdr;
 678         struct rt0_hdr *rthdr;
 679         struct net *net = dev_net(skb->dev);
 680         int accept_source_route = net->ipv6.devconf_all->accept_source_route;
 681
 682         idev = __in6_dev_get(skb->dev);
 683         if (idev && accept_source_route > idev->cnf.accept_source_route)
 684                 accept_source_route = idev->cnf.accept_source_route;
 685
 686         if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) ||
 687             !pskb_may_pull(skb, (skb_transport_offset(skb) +
 688                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
 689                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 690                 kfree_skb(skb);
 691                 return -1;
 692         }
 693
 694         hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 695
 696         if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) ||
 697             skb->pkt_type != PACKET_HOST) {
 698                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 699                 kfree_skb(skb);
 700                 return -1;
 701         }
 702
 703         switch (hdr->type) {
 704         case IPV6_SRCRT_TYPE_4:
 705                 /* segment routing */
 706                 return ipv6_srh_rcv(skb);
 707         case IPV6_SRCRT_TYPE_3:
 708                 /* rpl segment routing */
 709                 return ipv6_rpl_srh_rcv(skb);
 710         default:
 711                 break;
 712         }
 713
 714 looped_back:
 715         if (hdr->segments_left == 0) {
 716                 switch (hdr->type) {
 717 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 718                 case IPV6_SRCRT_TYPE_2:
 719                         /* Silently discard type 2 header unless it was
 720                          * processed by own
 721                          */
 722                         if (!addr) {
 723                                 __IP6_INC_STATS(net, idev,
 724                                                 IPSTATS_MIB_INADDRERRORS);
 725                                 kfree_skb(skb);
 726                                 return -1;
 727                         }
 728                         break;
 729 #endif
 730                 default:
 731                         break;
 732                 }
 733
 734                 opt->lastopt = opt->srcrt = skb_network_header_len(skb);
 735                 skb->transport_header += (hdr->hdrlen + 1) << 3;
 736                 opt->dst0 = opt->dst1;
 737                 opt->dst1 = 0;
 738                 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb);
 739                 return 1;
 740         }
 741
 742         switch (hdr->type) {
 743 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 744         case IPV6_SRCRT_TYPE_2:
 745                 if (accept_source_route < 0)
 746                         goto unknown_rh;
 747                 /* Silently discard invalid RTH type 2 */
 748                 if (hdr->hdrlen != 2 || hdr->segments_left != 1) {
 749                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 750                         kfree_skb(skb);
 751                         return -1;
 752                 }
 753                 break;
 754 #endif
 755         default:
 756                 goto unknown_rh;
 757         }
 758
 759         /*
 760          *      This is the routing header forwarding algorithm from
 761          *      RFC 2460, page 16.
 762          */
 763
 764         n = hdr->hdrlen >> 1;
 765
 766         if (hdr->segments_left > n) {
 767                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 768                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 769                                   ((&hdr->segments_left) -
 770                                    skb_network_header(skb)));
 771                 return -1;
 772         }
 773
 774         /* We are about to mangle packet header. Be careful!
 775            Do not damage packets queued somewhere.
 776          */
 777         if (skb_cloned(skb)) {
 778                 /* the copy is a forwarded packet */
 779                 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
 780                         __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)),
 781                                         IPSTATS_MIB_OUTDISCARDS);
 782                         kfree_skb(skb);
 783                         return -1;
 784                 }
 785                 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb);
 786         }
 787
 788         if (skb->ip_summed == CHECKSUM_COMPLETE)
 789                 skb->ip_summed = CHECKSUM_NONE;
 790
 791         i = n - --hdr->segments_left;
 792
 793         rthdr = (struct rt0_hdr *) hdr;
 794         addr = rthdr->addr;
 795         addr += i - 1;
 796
 797         switch (hdr->type) {
 798 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 799         case IPV6_SRCRT_TYPE_2:
 800                 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr,
 801                                      (xfrm_address_t *)&ipv6_hdr(skb)->saddr,
 802                                      IPPROTO_ROUTING) < 0) {
 803                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 804                         kfree_skb(skb);
 805                         return -1;
 806                 }
 807                 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) {
 808                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 809                         kfree_skb(skb);
 810                         return -1;
 811                 }
 812                 break;
 813 #endif
 814         default:
 815                 break;
 816         }
 817
 818         if (ipv6_addr_is_multicast(addr)) {
 819                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS);
 820                 kfree_skb(skb);
 821                 return -1;
 822         }
 823
 824         daddr = *addr;
 825         *addr = ipv6_hdr(skb)->daddr;
 826         ipv6_hdr(skb)->daddr = daddr;
 827
 828         skb_dst_drop(skb);
 829         ip6_route_input(skb);
 830         if (skb_dst(skb)->error) {
 831                 skb_push(skb, skb->data - skb_network_header(skb));
 832                 dst_input(skb);
 833                 return -1;
 834         }
 835
 836         if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) {
 837                 if (ipv6_hdr(skb)->hop_limit <= 1) {
 838                         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 839                         icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT,
 840                                     0);
 841                         kfree_skb(skb);
 842                         return -1;
 843                 }
 844                 ipv6_hdr(skb)->hop_limit--;
 845                 goto looped_back;
 846         }
 847
 848         skb_push(skb, skb->data - skb_network_header(skb));
 849         dst_input(skb);
 850         return -1;
 851
 852 unknown_rh:
 853         __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
 854         icmpv6_param_prob(skb, ICMPV6_HDR_FIELD,
 855                           (&hdr->type) - skb_network_header(skb));
 856         return -1;
 857 }
 858
 859 static const struct inet6_protocol rthdr_protocol = {
 860         .handler        =       ipv6_rthdr_rcv,
 861         .flags          =       INET6_PROTO_NOPOLICY,
 862 };
 863
 864 static const struct inet6_protocol destopt_protocol = {
 865         .handler        =       ipv6_destopt_rcv,
 866         .flags          =       INET6_PROTO_NOPOLICY,
 867 };
 868
 869 static const struct inet6_protocol nodata_protocol = {
 870         .handler        =       dst_discard,
 871         .flags          =       INET6_PROTO_NOPOLICY,
 872 };
 873
 874 int __init ipv6_exthdrs_init(void)
 875 {
 876         int ret;
 877
 878         ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 879         if (ret)
 880                 goto out;
 881
 882         ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 883         if (ret)
 884                 goto out_rthdr;
 885
 886         ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE);
 887         if (ret)
 888                 goto out_destopt;
 889
 890 out:
 891         return ret;
 892 out_destopt:
 893         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 894 out_rthdr:
 895         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 896         goto out;
 897 };
 898
 899 void ipv6_exthdrs_exit(void)
 900 {
 901         inet6_del_protocol(&nodata_protocol, IPPROTO_NONE);
 902         inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS);
 903         inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING);
 904 }
 905
 906 /**********************************
 907   Hop-by-hop options.
 908  **********************************/
 909
 910 /*
 911  * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input().
 912  */
 913 static inline struct net *ipv6_skb_net(struct sk_buff *skb)
 914 {
 915         return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev);
 916 }
 917
 918 /* Router Alert as of RFC 2711 */
 919
 920 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff)
 921 {
 922         const unsigned char *nh = skb_network_header(skb);
 923
 924         if (nh[optoff + 1] == 2) {
 925                 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT;
 926                 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra));
 927                 return true;
 928         }
 929         net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n",
 930                             nh[optoff + 1]);
 931         kfree_skb(skb);
 932         return false;
 933 }
 934
 935 /* IOAM */
 936
 937 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff)
 938 {
 939         struct ioam6_trace_hdr *trace;
 940         struct ioam6_namespace *ns;
 941         struct ioam6_hdr *hdr;
 942
 943         /* Bad alignment (must be 4n-aligned) */
 944         if (optoff & 3)
 945                 goto drop;
 946
 947         /* Ignore if IOAM is not enabled on ingress */
 948         if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled)
 949                 goto ignore;
 950
 951         /* Truncated Option header */
 952         hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff);
 953         if (hdr->opt_len < 2)
 954                 goto drop;
 955
 956         switch (hdr->type) {
 957         case IOAM6_TYPE_PREALLOC:
 958                 /* Truncated Pre-allocated Trace header */
 959                 if (hdr->opt_len < 2 + sizeof(*trace))
 960                         goto drop;
 961
 962                 /* Malformed Pre-allocated Trace header */
 963                 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr));
 964                 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4)
 965                         goto drop;
 966
 967                 /* Ignore if the IOAM namespace is unknown */
 968                 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id);
 969                 if (!ns)
 970                         goto ignore;
 971
 972                 if (!skb_valid_dst(skb))
 973                         ip6_route_input(skb);
 974
 975                 ioam6_fill_trace_data(skb, ns, trace);
 976                 break;
 977         default:
 978                 break;
 979         }
 980
 981 ignore:
 982         return true;
 983
 984 drop:
 985         kfree_skb(skb);
 986         return false;
 987 }
 988
 989 /* Jumbo payload */
 990
 991 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
 992 {
 993         const unsigned char *nh = skb_network_header(skb);
 994         struct inet6_dev *idev = __in6_dev_get_safely(skb->dev);
 995         struct net *net = ipv6_skb_net(skb);
 996         u32 pkt_len;
 997
 998         if (nh[optoff + 1] != 4 || (optoff & 3) != 2) {
 999                 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n",
1000                                     nh[optoff+1]);
1001                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1002                 goto drop;
1003         }
1004
1005         pkt_len = ntohl(*(__be32 *)(nh + optoff + 2));
1006         if (pkt_len <= IPV6_MAXPLEN) {
1007                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1008                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2);
1009                 return false;
1010         }
1011         if (ipv6_hdr(skb)->payload_len) {
1012                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);
1013                 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff);
1014                 return false;
1015         }
1016
1017         if (pkt_len > skb->len - sizeof(struct ipv6hdr)) {
1018                 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS);
1019                 goto drop;
1020         }
1021
1022         if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr)))
1023                 goto drop;
1024
1025         IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM;
1026         return true;
1027
1028 drop:
1029         kfree_skb(skb);
1030         return false;
1031 }
1032
1033 /* CALIPSO RFC 5570 */
1034
1035 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff)
1036 {
1037         const unsigned char *nh = skb_network_header(skb);
1038
1039         if (nh[optoff + 1] < 8)
1040                 goto drop;
1041
1042         if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1])
1043                 goto drop;
1044
1045         if (!calipso_validate(skb, nh + optoff))
1046                 goto drop;
1047
1048         return true;
1049
1050 drop:
1051         kfree_skb(skb);
1052         return false;
1053 }
1054
1055 int ipv6_parse_hopopts(struct sk_buff *skb)
1056 {
1057         struct inet6_skb_parm *opt = IP6CB(skb);
1058         struct net *net = dev_net(skb->dev);
1059         int extlen;
1060
1061         /*
1062          * skb_network_header(skb) is equal to skb->data, and
1063          * skb_network_header_len(skb) is always equal to
1064          * sizeof(struct ipv6hdr) by definition of
1065          * hop-by-hop options.
1066          */
1067         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) ||
1068             !pskb_may_pull(skb, (sizeof(struct ipv6hdr) +
1069                                  ((skb_transport_header(skb)[1] + 1) << 3)))) {
1070 fail_and_free:
1071                 kfree_skb(skb);
1072                 return -1;
1073         }
1074
1075         extlen = (skb_transport_header(skb)[1] + 1) << 3;
1076         if (extlen > net->ipv6.sysctl.max_hbh_opts_len)
1077                 goto fail_and_free;
1078
1079         opt->flags |= IP6SKB_HOPBYHOP;
1080         if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) {
1081                 skb->transport_header += extlen;
1082                 opt = IP6CB(skb);
1083                 opt->nhoff = sizeof(struct ipv6hdr);
1084                 return 1;
1085         }
1086         return -1;
1087 }
1088
1089 /*
1090  *      Creating outbound headers.
1091  *
1092  *      "build" functions work when skb is filled from head to tail (datagram)
1093  *      "push"  functions work when headers are added from tail to head (tcp)
1094  *
1095  *      In both cases we assume, that caller reserved enough room
1096  *      for headers.
1097  */
1098
1099 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto,
1100                              struct ipv6_rt_hdr *opt,
1101                              struct in6_addr **addr_p, struct in6_addr *saddr)
1102 {
1103         struct rt0_hdr *phdr, *ihdr;
1104         int hops;
1105
1106         ihdr = (struct rt0_hdr *) opt;
1107
1108         phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3);
1109         memcpy(phdr, ihdr, sizeof(struct rt0_hdr));
1110
1111         hops = ihdr->rt_hdr.hdrlen >> 1;
1112
1113         if (hops > 1)
1114                 memcpy(phdr->addr, ihdr->addr + 1,
1115                        (hops - 1) * sizeof(struct in6_addr));
1116
1117         phdr->addr[hops - 1] = **addr_p;
1118         *addr_p = ihdr->addr;
1119
1120         phdr->rt_hdr.nexthdr = *proto;
1121         *proto = NEXTHDR_ROUTING;
1122 }
1123
1124 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto,
1125                              struct ipv6_rt_hdr *opt,
1126                              struct in6_addr **addr_p, struct in6_addr *saddr)
1127 {
1128         struct ipv6_sr_hdr *sr_phdr, *sr_ihdr;
1129         int plen, hops;
1130
1131         sr_ihdr = (struct ipv6_sr_hdr *)opt;
1132         plen = (sr_ihdr->hdrlen + 1) << 3;
1133
1134         sr_phdr = skb_push(skb, plen);
1135         memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr));
1136
1137         hops = sr_ihdr->first_segment + 1;
1138         memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1,
1139                (hops - 1) * sizeof(struct in6_addr));
1140
1141         sr_phdr->segments[0] = **addr_p;
1142         *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left];
1143
1144         if (sr_ihdr->hdrlen > hops * 2) {
1145                 int tlvs_offset, tlvs_length;
1146
1147                 tlvs_offset = (1 + hops * 2) << 3;
1148                 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3;
1149                 memcpy((char *)sr_phdr + tlvs_offset,
1150                        (char *)sr_ihdr + tlvs_offset, tlvs_length);
1151         }
1152
1153 #ifdef CONFIG_IPV6_SEG6_HMAC
1154         if (sr_has_hmac(sr_phdr)) {
1155                 struct net *net = NULL;
1156
1157                 if (skb->dev)
1158                         net = dev_net(skb->dev);
1159                 else if (skb->sk)
1160                         net = sock_net(skb->sk);
1161
1162                 WARN_ON(!net);
1163
1164                 if (net)
1165                         seg6_push_hmac(net, saddr, sr_phdr);
1166         }
1167 #endif
1168
1169         sr_phdr->nexthdr = *proto;
1170         *proto = NEXTHDR_ROUTING;
1171 }
1172
1173 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto,
1174                             struct ipv6_rt_hdr *opt,
1175                             struct in6_addr **addr_p, struct in6_addr *saddr)
1176 {
1177         switch (opt->type) {
1178         case IPV6_SRCRT_TYPE_0:
1179         case IPV6_SRCRT_STRICT:
1180         case IPV6_SRCRT_TYPE_2:
1181                 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr);
1182                 break;
1183         case IPV6_SRCRT_TYPE_4:
1184                 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr);
1185                 break;
1186         default:
1187                 break;
1188         }
1189 }
1190
1191 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt)
1192 {
1193         struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt));
1194
1195         memcpy(h, opt, ipv6_optlen(opt));
1196         h->nexthdr = *proto;
1197         *proto = type;
1198 }
1199
1200 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
1201                           u8 *proto,
1202                           struct in6_addr **daddr, struct in6_addr *saddr)
1203 {
1204         if (opt->srcrt) {
1205                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr);
1206                 /*
1207                  * IPV6_RTHDRDSTOPTS is ignored
1208                  * unless IPV6_RTHDR is set (RFC3542).
1209                  */
1210                 if (opt->dst0opt)
1211                         ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
1212         }
1213         if (opt->hopopt)
1214                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
1215 }
1216
1217 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto)
1218 {
1219         if (opt->dst1opt)
1220                 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt);
1221 }
1222 EXPORT_SYMBOL(ipv6_push_frag_opts);
1223
1224 struct ipv6_txoptions *
1225 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
1226 {
1227         struct ipv6_txoptions *opt2;
1228
1229         opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC);
1230         if (opt2) {
1231                 long dif = (char *)opt2 - (char *)opt;
1232                 memcpy(opt2, opt, opt->tot_len);
1233                 if (opt2->hopopt)
1234                         *((char **)&opt2->hopopt) += dif;
1235                 if (opt2->dst0opt)
1236                         *((char **)&opt2->dst0opt) += dif;
1237                 if (opt2->dst1opt)
1238                         *((char **)&opt2->dst1opt) += dif;
1239                 if (opt2->srcrt)
1240                         *((char **)&opt2->srcrt) += dif;
1241                 refcount_set(&opt2->refcnt, 1);
1242         }
1243         return opt2;
1244 }
1245 EXPORT_SYMBOL_GPL(ipv6_dup_options);
1246
1247 static void ipv6_renew_option(int renewtype,
1248                               struct ipv6_opt_hdr **dest,
1249                               struct ipv6_opt_hdr *old,
1250                               struct ipv6_opt_hdr *new,
1251                               int newtype, char **p)
1252 {
1253         struct ipv6_opt_hdr *src;
1254
1255         src = (renewtype == newtype ? new : old);
1256         if (!src)
1257                 return;
1258
1259         memcpy(*p, src, ipv6_optlen(src));
1260         *dest = (struct ipv6_opt_hdr *)*p;
1261         *p += CMSG_ALIGN(ipv6_optlen(*dest));
1262 }
1263
1264 /**
1265  * ipv6_renew_options - replace a specific ext hdr with a new one.
1266  *
1267  * @sk: sock from which to allocate memory
1268  * @opt: original options
1269  * @newtype: option type to replace in @opt
1270  * @newopt: new option of type @newtype to replace (user-mem)
1271  *
1272  * Returns a new set of options which is a copy of @opt with the
1273  * option type @newtype replaced with @newopt.
1274  *
1275  * @opt may be NULL, in which case a new set of options is returned
1276  * containing just @newopt.
1277  *
1278  * @newopt may be NULL, in which case the specified option type is
1279  * not copied into the new set of options.
1280  *
1281  * The new set of options is allocated from the socket option memory
1282  * buffer of @sk.
1283  */
1284 struct ipv6_txoptions *
1285 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
1286                    int newtype, struct ipv6_opt_hdr *newopt)
1287 {
1288         int tot_len = 0;
1289         char *p;
1290         struct ipv6_txoptions *opt2;
1291
1292         if (opt) {
1293                 if (newtype != IPV6_HOPOPTS && opt->hopopt)
1294                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
1295                 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
1296                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
1297                 if (newtype != IPV6_RTHDR && opt->srcrt)
1298                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
1299                 if (newtype != IPV6_DSTOPTS && opt->dst1opt)
1300                         tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
1301         }
1302
1303         if (newopt)
1304                 tot_len += CMSG_ALIGN(ipv6_optlen(newopt));
1305
1306         if (!tot_len)
1307                 return NULL;
1308
1309         tot_len += sizeof(*opt2);
1310         opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
1311         if (!opt2)
1312                 return ERR_PTR(-ENOBUFS);
1313
1314         memset(opt2, 0, tot_len);
1315         refcount_set(&opt2->refcnt, 1);
1316         opt2->tot_len = tot_len;
1317         p = (char *)(opt2 + 1);
1318
1319         ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt,
1320                           (opt ? opt->hopopt : NULL),
1321                           newopt, newtype, &p);
1322         ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt,
1323                           (opt ? opt->dst0opt : NULL),
1324                           newopt, newtype, &p);
1325         ipv6_renew_option(IPV6_RTHDR,
1326                           (struct ipv6_opt_hdr **)&opt2->srcrt,
1327                           (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL),
1328                           newopt, newtype, &p);
1329         ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt,
1330                           (opt ? opt->dst1opt : NULL),
1331                           newopt, newtype, &p);
1332
1333         opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
1334                           (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
1335                           (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
1336         opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
1337
1338         return opt2;
1339 }
1340
1341 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space,
1342                                           struct ipv6_txoptions *opt)
1343 {
1344         /*
1345          * ignore the dest before srcrt unless srcrt is being included.
1346          * --yoshfuji
1347          */
1348         if (opt && opt->dst0opt && !opt->srcrt) {
1349                 if (opt_space != opt) {
1350                         memcpy(opt_space, opt, sizeof(*opt_space));
1351                         opt = opt_space;
1352                 }
1353                 opt->opt_nflen -= ipv6_optlen(opt->dst0opt);
1354                 opt->dst0opt = NULL;
1355         }
1356
1357         return opt;
1358 }
1359 EXPORT_SYMBOL_GPL(ipv6_fixup_options);
1360
1361 /**
1362  * fl6_update_dst - update flowi destination address with info given
1363  *                  by srcrt option, if any.
1364  *
1365  * @fl6: flowi6 for which daddr is to be updated
1366  * @opt: struct ipv6_txoptions in which to look for srcrt opt
1367  * @orig: copy of original daddr address if modified
1368  *
1369  * Returns NULL if no txoptions or no srcrt, otherwise returns orig
1370  * and initial value of fl6->daddr set in orig
1371  */
1372 struct in6_addr *fl6_update_dst(struct flowi6 *fl6,
1373                                 const struct ipv6_txoptions *opt,
1374                                 struct in6_addr *orig)
1375 {
1376         if (!opt || !opt->srcrt)
1377                 return NULL;
1378
1379         *orig = fl6->daddr;
1380
1381         switch (opt->srcrt->type) {
1382         case IPV6_SRCRT_TYPE_0:
1383         case IPV6_SRCRT_STRICT:
1384         case IPV6_SRCRT_TYPE_2:
1385                 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr;
1386                 break;
1387         case IPV6_SRCRT_TYPE_4:
1388         {
1389                 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt;
1390
1391                 fl6->daddr = srh->segments[srh->segments_left];
1392                 break;
1393         }
1394         default:
1395                 return NULL;
1396         }
1397
1398         return orig;
1399 }
1400 EXPORT_SYMBOL_GPL(fl6_update_dst);