1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Extension Header handling for IPv6 4 * Linux INET6 implementation 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * Andi Kleen <ak@muc.de> 9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 10 */ 11 12 /* Changes: 13 * yoshfuji : ensure not to overrun while parsing 14 * tlv options. 15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). 16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header 17 * handlers as inet6_protocol{}. 18 */ 19 20 #include <linux/errno.h> 21 #include <linux/types.h> 22 #include <linux/socket.h> 23 #include <linux/sockios.h> 24 #include <linux/net.h> 25 #include <linux/netdevice.h> 26 #include <linux/in6.h> 27 #include <linux/icmpv6.h> 28 #include <linux/slab.h> 29 #include <linux/export.h> 30 31 #include <net/dst.h> 32 #include <net/sock.h> 33 #include <net/snmp.h> 34 35 #include <net/ipv6.h> 36 #include <net/protocol.h> 37 #include <net/transp_v6.h> 38 #include <net/rawv6.h> 39 #include <net/ndisc.h> 40 #include <net/ip6_route.h> 41 #include <net/addrconf.h> 42 #include <net/calipso.h> 43 #if IS_ENABLED(CONFIG_IPV6_MIP6) 44 #include <net/xfrm.h> 45 #endif 46 #include <linux/seg6.h> 47 #include <net/seg6.h> 48 #ifdef CONFIG_IPV6_SEG6_HMAC 49 #include <net/seg6_hmac.h> 50 #endif 51 #include <net/rpl.h> 52 53 #include <linux/uaccess.h> 54 55 /* 56 * Parsing tlv encoded headers. 57 * 58 * Parsing function "func" returns true, if parsing succeed 59 * and false, if it failed. 60 * It MUST NOT touch skb->h. 61 */ 62 63 struct tlvtype_proc { 64 int type; 65 bool (*func)(struct sk_buff *skb, int offset); 66 }; 67 68 /********************* 69 Generic functions 70 *********************/ 71 72 /* An unknown option is detected, decide what to do */ 73 74 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff, 75 bool disallow_unknowns) 76 { 77 if (disallow_unknowns) { 78 /* If unknown TLVs are disallowed by configuration 79 * then always silently drop packet. Note this also 80 * means no ICMP parameter problem is sent which 81 * could be a good property to mitigate a reflection DOS 82 * attack. 83 */ 84 85 goto drop; 86 } 87 88 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 89 case 0: /* ignore */ 90 return true; 91 92 case 1: /* drop packet */ 93 break; 94 95 case 3: /* Send ICMP if not a multicast address and drop packet */ 96 /* Actually, it is redundant check. icmp_send 97 will recheck in any case. 98 */ 99 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 100 break; 101 fallthrough; 102 case 2: /* send ICMP PARM PROB regardless and drop packet */ 103 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 104 return false; 105 } 106 107 drop: 108 kfree_skb(skb); 109 return false; 110 } 111 112 /* Parse tlv encoded option header (hop-by-hop or destination) */ 113 114 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, 115 struct sk_buff *skb, 116 int max_count) 117 { 118 int len = (skb_transport_header(skb)[1] + 1) << 3; 119 const unsigned char *nh = skb_network_header(skb); 120 int off = skb_network_header_len(skb); 121 const struct tlvtype_proc *curr; 122 bool disallow_unknowns = false; 123 int tlv_count = 0; 124 int padlen = 0; 125 126 if (unlikely(max_count < 0)) { 127 disallow_unknowns = true; 128 max_count = -max_count; 129 } 130 131 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 132 goto bad; 133 134 off += 2; 135 len -= 2; 136 137 while (len > 0) { 138 int optlen = nh[off + 1] + 2; 139 int i; 140 141 switch (nh[off]) { 142 case IPV6_TLV_PAD1: 143 optlen = 1; 144 padlen++; 145 if (padlen > 7) 146 goto bad; 147 break; 148 149 case IPV6_TLV_PADN: 150 /* RFC 2460 states that the purpose of PadN is 151 * to align the containing header to multiples 152 * of 8. 7 is therefore the highest valid value. 153 * See also RFC 4942, Section 2.1.9.5. 154 */ 155 padlen += optlen; 156 if (padlen > 7) 157 goto bad; 158 /* RFC 4942 recommends receiving hosts to 159 * actively check PadN payload to contain 160 * only zeroes. 161 */ 162 for (i = 2; i < optlen; i++) { 163 if (nh[off + i] != 0) 164 goto bad; 165 } 166 break; 167 168 default: /* Other TLV code so scan list */ 169 if (optlen > len) 170 goto bad; 171 172 tlv_count++; 173 if (tlv_count > max_count) 174 goto bad; 175 176 for (curr = procs; curr->type >= 0; curr++) { 177 if (curr->type == nh[off]) { 178 /* type specific length/alignment 179 checks will be performed in the 180 func(). */ 181 if (curr->func(skb, off) == false) 182 return false; 183 break; 184 } 185 } 186 if (curr->type < 0 && 187 !ip6_tlvopt_unknown(skb, off, disallow_unknowns)) 188 return false; 189 190 padlen = 0; 191 break; 192 } 193 off += optlen; 194 len -= optlen; 195 } 196 197 if (len == 0) 198 return true; 199 bad: 200 kfree_skb(skb); 201 return false; 202 } 203 204 /***************************** 205 Destination options header. 206 *****************************/ 207 208 #if IS_ENABLED(CONFIG_IPV6_MIP6) 209 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 210 { 211 struct ipv6_destopt_hao *hao; 212 struct inet6_skb_parm *opt = IP6CB(skb); 213 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 214 int ret; 215 216 if (opt->dsthao) { 217 net_dbg_ratelimited("hao duplicated\n"); 218 goto discard; 219 } 220 opt->dsthao = opt->dst1; 221 opt->dst1 = 0; 222 223 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 224 225 if (hao->length != 16) { 226 net_dbg_ratelimited("hao invalid option length = %d\n", 227 hao->length); 228 goto discard; 229 } 230 231 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 232 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 233 &hao->addr); 234 goto discard; 235 } 236 237 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 238 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 239 if (unlikely(ret < 0)) 240 goto discard; 241 242 if (skb_cloned(skb)) { 243 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 244 goto discard; 245 246 /* update all variable using below by copied skbuff */ 247 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 248 optoff); 249 ipv6h = ipv6_hdr(skb); 250 } 251 252 if (skb->ip_summed == CHECKSUM_COMPLETE) 253 skb->ip_summed = CHECKSUM_NONE; 254 255 swap(ipv6h->saddr, hao->addr); 256 257 if (skb->tstamp == 0) 258 __net_timestamp(skb); 259 260 return true; 261 262 discard: 263 kfree_skb(skb); 264 return false; 265 } 266 #endif 267 268 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 269 #if IS_ENABLED(CONFIG_IPV6_MIP6) 270 { 271 .type = IPV6_TLV_HAO, 272 .func = ipv6_dest_hao, 273 }, 274 #endif 275 {-1, NULL} 276 }; 277 278 static int ipv6_destopt_rcv(struct sk_buff *skb) 279 { 280 struct inet6_dev *idev = __in6_dev_get(skb->dev); 281 struct inet6_skb_parm *opt = IP6CB(skb); 282 #if IS_ENABLED(CONFIG_IPV6_MIP6) 283 __u16 dstbuf; 284 #endif 285 struct dst_entry *dst = skb_dst(skb); 286 struct net *net = dev_net(skb->dev); 287 int extlen; 288 289 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 290 !pskb_may_pull(skb, (skb_transport_offset(skb) + 291 ((skb_transport_header(skb)[1] + 1) << 3)))) { 292 __IP6_INC_STATS(dev_net(dst->dev), idev, 293 IPSTATS_MIB_INHDRERRORS); 294 fail_and_free: 295 kfree_skb(skb); 296 return -1; 297 } 298 299 extlen = (skb_transport_header(skb)[1] + 1) << 3; 300 if (extlen > net->ipv6.sysctl.max_dst_opts_len) 301 goto fail_and_free; 302 303 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 304 #if IS_ENABLED(CONFIG_IPV6_MIP6) 305 dstbuf = opt->dst1; 306 #endif 307 308 if (ip6_parse_tlv(tlvprocdestopt_lst, skb, 309 init_net.ipv6.sysctl.max_dst_opts_cnt)) { 310 skb->transport_header += extlen; 311 opt = IP6CB(skb); 312 #if IS_ENABLED(CONFIG_IPV6_MIP6) 313 opt->nhoff = dstbuf; 314 #else 315 opt->nhoff = opt->dst1; 316 #endif 317 return 1; 318 } 319 320 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 321 return -1; 322 } 323 324 static void seg6_update_csum(struct sk_buff *skb) 325 { 326 struct ipv6_sr_hdr *hdr; 327 struct in6_addr *addr; 328 __be32 from, to; 329 330 /* srh is at transport offset and seg_left is already decremented 331 * but daddr is not yet updated with next segment 332 */ 333 334 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 335 addr = hdr->segments + hdr->segments_left; 336 337 hdr->segments_left++; 338 from = *(__be32 *)hdr; 339 340 hdr->segments_left--; 341 to = *(__be32 *)hdr; 342 343 /* update skb csum with diff resulting from seg_left decrement */ 344 345 update_csum_diff4(skb, from, to); 346 347 /* compute csum diff between current and next segment and update */ 348 349 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 350 (__be32 *)addr); 351 } 352 353 static int ipv6_srh_rcv(struct sk_buff *skb) 354 { 355 struct inet6_skb_parm *opt = IP6CB(skb); 356 struct net *net = dev_net(skb->dev); 357 struct ipv6_sr_hdr *hdr; 358 struct inet6_dev *idev; 359 struct in6_addr *addr; 360 int accept_seg6; 361 362 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 363 364 idev = __in6_dev_get(skb->dev); 365 366 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 367 if (accept_seg6 > idev->cnf.seg6_enabled) 368 accept_seg6 = idev->cnf.seg6_enabled; 369 370 if (!accept_seg6) { 371 kfree_skb(skb); 372 return -1; 373 } 374 375 #ifdef CONFIG_IPV6_SEG6_HMAC 376 if (!seg6_hmac_validate_skb(skb)) { 377 kfree_skb(skb); 378 return -1; 379 } 380 #endif 381 382 looped_back: 383 if (hdr->segments_left == 0) { 384 if (hdr->nexthdr == NEXTHDR_IPV6) { 385 int offset = (hdr->hdrlen + 1) << 3; 386 387 skb_postpull_rcsum(skb, skb_network_header(skb), 388 skb_network_header_len(skb)); 389 390 if (!pskb_pull(skb, offset)) { 391 kfree_skb(skb); 392 return -1; 393 } 394 skb_postpull_rcsum(skb, skb_transport_header(skb), 395 offset); 396 397 skb_reset_network_header(skb); 398 skb_reset_transport_header(skb); 399 skb->encapsulation = 0; 400 401 __skb_tunnel_rx(skb, skb->dev, net); 402 403 netif_rx(skb); 404 return -1; 405 } 406 407 opt->srcrt = skb_network_header_len(skb); 408 opt->lastopt = opt->srcrt; 409 skb->transport_header += (hdr->hdrlen + 1) << 3; 410 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 411 412 return 1; 413 } 414 415 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 416 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 417 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 418 ((&hdr->segments_left) - 419 skb_network_header(skb))); 420 return -1; 421 } 422 423 if (skb_cloned(skb)) { 424 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 425 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 426 IPSTATS_MIB_OUTDISCARDS); 427 kfree_skb(skb); 428 return -1; 429 } 430 } 431 432 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 433 434 hdr->segments_left--; 435 addr = hdr->segments + hdr->segments_left; 436 437 skb_push(skb, sizeof(struct ipv6hdr)); 438 439 if (skb->ip_summed == CHECKSUM_COMPLETE) 440 seg6_update_csum(skb); 441 442 ipv6_hdr(skb)->daddr = *addr; 443 444 skb_dst_drop(skb); 445 446 ip6_route_input(skb); 447 448 if (skb_dst(skb)->error) { 449 dst_input(skb); 450 return -1; 451 } 452 453 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 454 if (ipv6_hdr(skb)->hop_limit <= 1) { 455 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 456 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 457 ICMPV6_EXC_HOPLIMIT, 0); 458 kfree_skb(skb); 459 return -1; 460 } 461 ipv6_hdr(skb)->hop_limit--; 462 463 skb_pull(skb, sizeof(struct ipv6hdr)); 464 goto looped_back; 465 } 466 467 dst_input(skb); 468 469 return -1; 470 } 471 472 static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 473 { 474 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 475 struct inet6_skb_parm *opt = IP6CB(skb); 476 struct net *net = dev_net(skb->dev); 477 struct inet6_dev *idev; 478 struct ipv6hdr *oldhdr; 479 struct in6_addr addr; 480 unsigned char *buf; 481 int accept_rpl_seg; 482 int i, err; 483 u64 n = 0; 484 u32 r; 485 486 idev = __in6_dev_get(skb->dev); 487 488 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled; 489 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled) 490 accept_rpl_seg = idev->cnf.rpl_seg_enabled; 491 492 if (!accept_rpl_seg) { 493 kfree_skb(skb); 494 return -1; 495 } 496 497 looped_back: 498 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 499 500 if (hdr->segments_left == 0) { 501 if (hdr->nexthdr == NEXTHDR_IPV6) { 502 int offset = (hdr->hdrlen + 1) << 3; 503 504 skb_postpull_rcsum(skb, skb_network_header(skb), 505 skb_network_header_len(skb)); 506 507 if (!pskb_pull(skb, offset)) { 508 kfree_skb(skb); 509 return -1; 510 } 511 skb_postpull_rcsum(skb, skb_transport_header(skb), 512 offset); 513 514 skb_reset_network_header(skb); 515 skb_reset_transport_header(skb); 516 skb->encapsulation = 0; 517 518 __skb_tunnel_rx(skb, skb->dev, net); 519 520 netif_rx(skb); 521 return -1; 522 } 523 524 opt->srcrt = skb_network_header_len(skb); 525 opt->lastopt = opt->srcrt; 526 skb->transport_header += (hdr->hdrlen + 1) << 3; 527 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 528 529 return 1; 530 } 531 532 if (!pskb_may_pull(skb, sizeof(*hdr))) { 533 kfree_skb(skb); 534 return -1; 535 } 536 537 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 538 r = do_div(n, (16 - hdr->cmpri)); 539 /* checks if calculation was without remainder and n fits into 540 * unsigned char which is segments_left field. Should not be 541 * higher than that. 542 */ 543 if (r || (n + 1) > 255) { 544 kfree_skb(skb); 545 return -1; 546 } 547 548 if (hdr->segments_left > n + 1) { 549 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 550 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 551 ((&hdr->segments_left) - 552 skb_network_header(skb))); 553 return -1; 554 } 555 556 if (skb_cloned(skb)) { 557 if (pskb_expand_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE, 0, 558 GFP_ATOMIC)) { 559 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 560 IPSTATS_MIB_OUTDISCARDS); 561 kfree_skb(skb); 562 return -1; 563 } 564 } else { 565 err = skb_cow_head(skb, IPV6_RPL_SRH_WORST_SWAP_SIZE); 566 if (unlikely(err)) { 567 kfree_skb(skb); 568 return -1; 569 } 570 } 571 572 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 573 574 if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri, 575 hdr->cmpre))) { 576 kfree_skb(skb); 577 return -1; 578 } 579 580 hdr->segments_left--; 581 i = n - hdr->segments_left; 582 583 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 584 if (unlikely(!buf)) { 585 kfree_skb(skb); 586 return -1; 587 } 588 589 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 590 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 591 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 592 593 if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) || 594 (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) { 595 kfree_skb(skb); 596 kfree(buf); 597 return -1; 598 } 599 600 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 601 if (err) { 602 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 603 kfree_skb(skb); 604 kfree(buf); 605 return -1; 606 } 607 608 addr = ipv6_hdr(skb)->daddr; 609 ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i]; 610 ohdr->rpl_segaddr[i] = addr; 611 612 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 613 614 oldhdr = ipv6_hdr(skb); 615 616 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 617 skb_postpull_rcsum(skb, oldhdr, 618 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 619 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 620 skb_reset_network_header(skb); 621 skb_mac_header_rebuild(skb); 622 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 623 624 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 625 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 626 627 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 628 skb_postpush_rcsum(skb, ipv6_hdr(skb), 629 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 630 631 kfree(buf); 632 633 skb_dst_drop(skb); 634 635 ip6_route_input(skb); 636 637 if (skb_dst(skb)->error) { 638 dst_input(skb); 639 return -1; 640 } 641 642 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 643 if (ipv6_hdr(skb)->hop_limit <= 1) { 644 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 645 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 646 ICMPV6_EXC_HOPLIMIT, 0); 647 kfree_skb(skb); 648 return -1; 649 } 650 ipv6_hdr(skb)->hop_limit--; 651 652 skb_pull(skb, sizeof(struct ipv6hdr)); 653 goto looped_back; 654 } 655 656 dst_input(skb); 657 658 return -1; 659 } 660 661 /******************************** 662 Routing header. 663 ********************************/ 664 665 /* called with rcu_read_lock() */ 666 static int ipv6_rthdr_rcv(struct sk_buff *skb) 667 { 668 struct inet6_dev *idev = __in6_dev_get(skb->dev); 669 struct inet6_skb_parm *opt = IP6CB(skb); 670 struct in6_addr *addr = NULL; 671 struct in6_addr daddr; 672 int n, i; 673 struct ipv6_rt_hdr *hdr; 674 struct rt0_hdr *rthdr; 675 struct net *net = dev_net(skb->dev); 676 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 677 678 idev = __in6_dev_get(skb->dev); 679 if (idev && accept_source_route > idev->cnf.accept_source_route) 680 accept_source_route = idev->cnf.accept_source_route; 681 682 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 683 !pskb_may_pull(skb, (skb_transport_offset(skb) + 684 ((skb_transport_header(skb)[1] + 1) << 3)))) { 685 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 686 kfree_skb(skb); 687 return -1; 688 } 689 690 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 691 692 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 693 skb->pkt_type != PACKET_HOST) { 694 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 695 kfree_skb(skb); 696 return -1; 697 } 698 699 switch (hdr->type) { 700 case IPV6_SRCRT_TYPE_4: 701 /* segment routing */ 702 return ipv6_srh_rcv(skb); 703 case IPV6_SRCRT_TYPE_3: 704 /* rpl segment routing */ 705 return ipv6_rpl_srh_rcv(skb); 706 default: 707 break; 708 } 709 710 looped_back: 711 if (hdr->segments_left == 0) { 712 switch (hdr->type) { 713 #if IS_ENABLED(CONFIG_IPV6_MIP6) 714 case IPV6_SRCRT_TYPE_2: 715 /* Silently discard type 2 header unless it was 716 * processed by own 717 */ 718 if (!addr) { 719 __IP6_INC_STATS(net, idev, 720 IPSTATS_MIB_INADDRERRORS); 721 kfree_skb(skb); 722 return -1; 723 } 724 break; 725 #endif 726 default: 727 break; 728 } 729 730 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 731 skb->transport_header += (hdr->hdrlen + 1) << 3; 732 opt->dst0 = opt->dst1; 733 opt->dst1 = 0; 734 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 735 return 1; 736 } 737 738 switch (hdr->type) { 739 #if IS_ENABLED(CONFIG_IPV6_MIP6) 740 case IPV6_SRCRT_TYPE_2: 741 if (accept_source_route < 0) 742 goto unknown_rh; 743 /* Silently discard invalid RTH type 2 */ 744 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 745 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 746 kfree_skb(skb); 747 return -1; 748 } 749 break; 750 #endif 751 default: 752 goto unknown_rh; 753 } 754 755 /* 756 * This is the routing header forwarding algorithm from 757 * RFC 2460, page 16. 758 */ 759 760 n = hdr->hdrlen >> 1; 761 762 if (hdr->segments_left > n) { 763 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 764 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 765 ((&hdr->segments_left) - 766 skb_network_header(skb))); 767 return -1; 768 } 769 770 /* We are about to mangle packet header. Be careful! 771 Do not damage packets queued somewhere. 772 */ 773 if (skb_cloned(skb)) { 774 /* the copy is a forwarded packet */ 775 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 776 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 777 IPSTATS_MIB_OUTDISCARDS); 778 kfree_skb(skb); 779 return -1; 780 } 781 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 782 } 783 784 if (skb->ip_summed == CHECKSUM_COMPLETE) 785 skb->ip_summed = CHECKSUM_NONE; 786 787 i = n - --hdr->segments_left; 788 789 rthdr = (struct rt0_hdr *) hdr; 790 addr = rthdr->addr; 791 addr += i - 1; 792 793 switch (hdr->type) { 794 #if IS_ENABLED(CONFIG_IPV6_MIP6) 795 case IPV6_SRCRT_TYPE_2: 796 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 797 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 798 IPPROTO_ROUTING) < 0) { 799 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 800 kfree_skb(skb); 801 return -1; 802 } 803 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 804 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 805 kfree_skb(skb); 806 return -1; 807 } 808 break; 809 #endif 810 default: 811 break; 812 } 813 814 if (ipv6_addr_is_multicast(addr)) { 815 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 816 kfree_skb(skb); 817 return -1; 818 } 819 820 daddr = *addr; 821 *addr = ipv6_hdr(skb)->daddr; 822 ipv6_hdr(skb)->daddr = daddr; 823 824 skb_dst_drop(skb); 825 ip6_route_input(skb); 826 if (skb_dst(skb)->error) { 827 skb_push(skb, skb->data - skb_network_header(skb)); 828 dst_input(skb); 829 return -1; 830 } 831 832 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 833 if (ipv6_hdr(skb)->hop_limit <= 1) { 834 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 835 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 836 0); 837 kfree_skb(skb); 838 return -1; 839 } 840 ipv6_hdr(skb)->hop_limit--; 841 goto looped_back; 842 } 843 844 skb_push(skb, skb->data - skb_network_header(skb)); 845 dst_input(skb); 846 return -1; 847 848 unknown_rh: 849 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 850 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 851 (&hdr->type) - skb_network_header(skb)); 852 return -1; 853 } 854 855 static const struct inet6_protocol rthdr_protocol = { 856 .handler = ipv6_rthdr_rcv, 857 .flags = INET6_PROTO_NOPOLICY, 858 }; 859 860 static const struct inet6_protocol destopt_protocol = { 861 .handler = ipv6_destopt_rcv, 862 .flags = INET6_PROTO_NOPOLICY, 863 }; 864 865 static const struct inet6_protocol nodata_protocol = { 866 .handler = dst_discard, 867 .flags = INET6_PROTO_NOPOLICY, 868 }; 869 870 int __init ipv6_exthdrs_init(void) 871 { 872 int ret; 873 874 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 875 if (ret) 876 goto out; 877 878 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 879 if (ret) 880 goto out_rthdr; 881 882 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 883 if (ret) 884 goto out_destopt; 885 886 out: 887 return ret; 888 out_destopt: 889 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 890 out_rthdr: 891 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 892 goto out; 893 }; 894 895 void ipv6_exthdrs_exit(void) 896 { 897 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 898 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 899 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 900 } 901 902 /********************************** 903 Hop-by-hop options. 904 **********************************/ 905 906 /* 907 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 908 */ 909 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 910 { 911 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 912 } 913 914 /* Router Alert as of RFC 2711 */ 915 916 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 917 { 918 const unsigned char *nh = skb_network_header(skb); 919 920 if (nh[optoff + 1] == 2) { 921 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 922 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 923 return true; 924 } 925 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 926 nh[optoff + 1]); 927 kfree_skb(skb); 928 return false; 929 } 930 931 /* Jumbo payload */ 932 933 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 934 { 935 const unsigned char *nh = skb_network_header(skb); 936 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev); 937 struct net *net = ipv6_skb_net(skb); 938 u32 pkt_len; 939 940 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 941 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 942 nh[optoff+1]); 943 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 944 goto drop; 945 } 946 947 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 948 if (pkt_len <= IPV6_MAXPLEN) { 949 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 950 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 951 return false; 952 } 953 if (ipv6_hdr(skb)->payload_len) { 954 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 955 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 956 return false; 957 } 958 959 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 960 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS); 961 goto drop; 962 } 963 964 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 965 goto drop; 966 967 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 968 return true; 969 970 drop: 971 kfree_skb(skb); 972 return false; 973 } 974 975 /* CALIPSO RFC 5570 */ 976 977 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 978 { 979 const unsigned char *nh = skb_network_header(skb); 980 981 if (nh[optoff + 1] < 8) 982 goto drop; 983 984 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 985 goto drop; 986 987 if (!calipso_validate(skb, nh + optoff)) 988 goto drop; 989 990 return true; 991 992 drop: 993 kfree_skb(skb); 994 return false; 995 } 996 997 static const struct tlvtype_proc tlvprochopopt_lst[] = { 998 { 999 .type = IPV6_TLV_ROUTERALERT, 1000 .func = ipv6_hop_ra, 1001 }, 1002 { 1003 .type = IPV6_TLV_JUMBO, 1004 .func = ipv6_hop_jumbo, 1005 }, 1006 { 1007 .type = IPV6_TLV_CALIPSO, 1008 .func = ipv6_hop_calipso, 1009 }, 1010 { -1, } 1011 }; 1012 1013 int ipv6_parse_hopopts(struct sk_buff *skb) 1014 { 1015 struct inet6_skb_parm *opt = IP6CB(skb); 1016 struct net *net = dev_net(skb->dev); 1017 int extlen; 1018 1019 /* 1020 * skb_network_header(skb) is equal to skb->data, and 1021 * skb_network_header_len(skb) is always equal to 1022 * sizeof(struct ipv6hdr) by definition of 1023 * hop-by-hop options. 1024 */ 1025 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1026 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1027 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1028 fail_and_free: 1029 kfree_skb(skb); 1030 return -1; 1031 } 1032 1033 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1034 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 1035 goto fail_and_free; 1036 1037 opt->flags |= IP6SKB_HOPBYHOP; 1038 if (ip6_parse_tlv(tlvprochopopt_lst, skb, 1039 init_net.ipv6.sysctl.max_hbh_opts_cnt)) { 1040 skb->transport_header += extlen; 1041 opt = IP6CB(skb); 1042 opt->nhoff = sizeof(struct ipv6hdr); 1043 return 1; 1044 } 1045 return -1; 1046 } 1047 1048 /* 1049 * Creating outbound headers. 1050 * 1051 * "build" functions work when skb is filled from head to tail (datagram) 1052 * "push" functions work when headers are added from tail to head (tcp) 1053 * 1054 * In both cases we assume, that caller reserved enough room 1055 * for headers. 1056 */ 1057 1058 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1059 struct ipv6_rt_hdr *opt, 1060 struct in6_addr **addr_p, struct in6_addr *saddr) 1061 { 1062 struct rt0_hdr *phdr, *ihdr; 1063 int hops; 1064 1065 ihdr = (struct rt0_hdr *) opt; 1066 1067 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1068 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1069 1070 hops = ihdr->rt_hdr.hdrlen >> 1; 1071 1072 if (hops > 1) 1073 memcpy(phdr->addr, ihdr->addr + 1, 1074 (hops - 1) * sizeof(struct in6_addr)); 1075 1076 phdr->addr[hops - 1] = **addr_p; 1077 *addr_p = ihdr->addr; 1078 1079 phdr->rt_hdr.nexthdr = *proto; 1080 *proto = NEXTHDR_ROUTING; 1081 } 1082 1083 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1084 struct ipv6_rt_hdr *opt, 1085 struct in6_addr **addr_p, struct in6_addr *saddr) 1086 { 1087 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1088 int plen, hops; 1089 1090 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1091 plen = (sr_ihdr->hdrlen + 1) << 3; 1092 1093 sr_phdr = skb_push(skb, plen); 1094 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1095 1096 hops = sr_ihdr->first_segment + 1; 1097 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1098 (hops - 1) * sizeof(struct in6_addr)); 1099 1100 sr_phdr->segments[0] = **addr_p; 1101 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1102 1103 if (sr_ihdr->hdrlen > hops * 2) { 1104 int tlvs_offset, tlvs_length; 1105 1106 tlvs_offset = (1 + hops * 2) << 3; 1107 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1108 memcpy((char *)sr_phdr + tlvs_offset, 1109 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1110 } 1111 1112 #ifdef CONFIG_IPV6_SEG6_HMAC 1113 if (sr_has_hmac(sr_phdr)) { 1114 struct net *net = NULL; 1115 1116 if (skb->dev) 1117 net = dev_net(skb->dev); 1118 else if (skb->sk) 1119 net = sock_net(skb->sk); 1120 1121 WARN_ON(!net); 1122 1123 if (net) 1124 seg6_push_hmac(net, saddr, sr_phdr); 1125 } 1126 #endif 1127 1128 sr_phdr->nexthdr = *proto; 1129 *proto = NEXTHDR_ROUTING; 1130 } 1131 1132 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1133 struct ipv6_rt_hdr *opt, 1134 struct in6_addr **addr_p, struct in6_addr *saddr) 1135 { 1136 switch (opt->type) { 1137 case IPV6_SRCRT_TYPE_0: 1138 case IPV6_SRCRT_STRICT: 1139 case IPV6_SRCRT_TYPE_2: 1140 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1141 break; 1142 case IPV6_SRCRT_TYPE_4: 1143 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1144 break; 1145 default: 1146 break; 1147 } 1148 } 1149 1150 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1151 { 1152 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1153 1154 memcpy(h, opt, ipv6_optlen(opt)); 1155 h->nexthdr = *proto; 1156 *proto = type; 1157 } 1158 1159 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1160 u8 *proto, 1161 struct in6_addr **daddr, struct in6_addr *saddr) 1162 { 1163 if (opt->srcrt) { 1164 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1165 /* 1166 * IPV6_RTHDRDSTOPTS is ignored 1167 * unless IPV6_RTHDR is set (RFC3542). 1168 */ 1169 if (opt->dst0opt) 1170 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1171 } 1172 if (opt->hopopt) 1173 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1174 } 1175 1176 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1177 { 1178 if (opt->dst1opt) 1179 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1180 } 1181 EXPORT_SYMBOL(ipv6_push_frag_opts); 1182 1183 struct ipv6_txoptions * 1184 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1185 { 1186 struct ipv6_txoptions *opt2; 1187 1188 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 1189 if (opt2) { 1190 long dif = (char *)opt2 - (char *)opt; 1191 memcpy(opt2, opt, opt->tot_len); 1192 if (opt2->hopopt) 1193 *((char **)&opt2->hopopt) += dif; 1194 if (opt2->dst0opt) 1195 *((char **)&opt2->dst0opt) += dif; 1196 if (opt2->dst1opt) 1197 *((char **)&opt2->dst1opt) += dif; 1198 if (opt2->srcrt) 1199 *((char **)&opt2->srcrt) += dif; 1200 refcount_set(&opt2->refcnt, 1); 1201 } 1202 return opt2; 1203 } 1204 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1205 1206 static void ipv6_renew_option(int renewtype, 1207 struct ipv6_opt_hdr **dest, 1208 struct ipv6_opt_hdr *old, 1209 struct ipv6_opt_hdr *new, 1210 int newtype, char **p) 1211 { 1212 struct ipv6_opt_hdr *src; 1213 1214 src = (renewtype == newtype ? new : old); 1215 if (!src) 1216 return; 1217 1218 memcpy(*p, src, ipv6_optlen(src)); 1219 *dest = (struct ipv6_opt_hdr *)*p; 1220 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1221 } 1222 1223 /** 1224 * ipv6_renew_options - replace a specific ext hdr with a new one. 1225 * 1226 * @sk: sock from which to allocate memory 1227 * @opt: original options 1228 * @newtype: option type to replace in @opt 1229 * @newopt: new option of type @newtype to replace (user-mem) 1230 * 1231 * Returns a new set of options which is a copy of @opt with the 1232 * option type @newtype replaced with @newopt. 1233 * 1234 * @opt may be NULL, in which case a new set of options is returned 1235 * containing just @newopt. 1236 * 1237 * @newopt may be NULL, in which case the specified option type is 1238 * not copied into the new set of options. 1239 * 1240 * The new set of options is allocated from the socket option memory 1241 * buffer of @sk. 1242 */ 1243 struct ipv6_txoptions * 1244 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1245 int newtype, struct ipv6_opt_hdr *newopt) 1246 { 1247 int tot_len = 0; 1248 char *p; 1249 struct ipv6_txoptions *opt2; 1250 1251 if (opt) { 1252 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1253 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1254 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1255 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1256 if (newtype != IPV6_RTHDR && opt->srcrt) 1257 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1258 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1259 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1260 } 1261 1262 if (newopt) 1263 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1264 1265 if (!tot_len) 1266 return NULL; 1267 1268 tot_len += sizeof(*opt2); 1269 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1270 if (!opt2) 1271 return ERR_PTR(-ENOBUFS); 1272 1273 memset(opt2, 0, tot_len); 1274 refcount_set(&opt2->refcnt, 1); 1275 opt2->tot_len = tot_len; 1276 p = (char *)(opt2 + 1); 1277 1278 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1279 (opt ? opt->hopopt : NULL), 1280 newopt, newtype, &p); 1281 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1282 (opt ? opt->dst0opt : NULL), 1283 newopt, newtype, &p); 1284 ipv6_renew_option(IPV6_RTHDR, 1285 (struct ipv6_opt_hdr **)&opt2->srcrt, 1286 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1287 newopt, newtype, &p); 1288 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1289 (opt ? opt->dst1opt : NULL), 1290 newopt, newtype, &p); 1291 1292 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1293 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1294 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1295 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1296 1297 return opt2; 1298 } 1299 1300 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1301 struct ipv6_txoptions *opt) 1302 { 1303 /* 1304 * ignore the dest before srcrt unless srcrt is being included. 1305 * --yoshfuji 1306 */ 1307 if (opt && opt->dst0opt && !opt->srcrt) { 1308 if (opt_space != opt) { 1309 memcpy(opt_space, opt, sizeof(*opt_space)); 1310 opt = opt_space; 1311 } 1312 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1313 opt->dst0opt = NULL; 1314 } 1315 1316 return opt; 1317 } 1318 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1319 1320 /** 1321 * fl6_update_dst - update flowi destination address with info given 1322 * by srcrt option, if any. 1323 * 1324 * @fl6: flowi6 for which daddr is to be updated 1325 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1326 * @orig: copy of original daddr address if modified 1327 * 1328 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1329 * and initial value of fl6->daddr set in orig 1330 */ 1331 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1332 const struct ipv6_txoptions *opt, 1333 struct in6_addr *orig) 1334 { 1335 if (!opt || !opt->srcrt) 1336 return NULL; 1337 1338 *orig = fl6->daddr; 1339 1340 switch (opt->srcrt->type) { 1341 case IPV6_SRCRT_TYPE_0: 1342 case IPV6_SRCRT_STRICT: 1343 case IPV6_SRCRT_TYPE_2: 1344 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1345 break; 1346 case IPV6_SRCRT_TYPE_4: 1347 { 1348 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1349 1350 fl6->daddr = srh->segments[srh->segments_left]; 1351 break; 1352 } 1353 default: 1354 return NULL; 1355 } 1356 1357 return orig; 1358 } 1359 EXPORT_SYMBOL_GPL(fl6_update_dst); 1360