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 63struct 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 74static 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 107drop: 108 kfree_skb(skb); 109 return false; 110} 111 112/* Parse tlv encoded option header (hop-by-hop or destination) */ 113 114static 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, i; 139 140 if (nh[off] == IPV6_TLV_PAD1) { 141 padlen++; 142 if (padlen > 7) 143 goto bad; 144 off++; 145 len--; 146 continue; 147 } 148 if (len < 2) 149 goto bad; 150 optlen = nh[off + 1] + 2; 151 if (optlen > len) 152 goto bad; 153 154 if (nh[off] == IPV6_TLV_PADN) { 155 /* RFC 2460 states that the purpose of PadN is 156 * to align the containing header to multiples 157 * of 8. 7 is therefore the highest valid value. 158 * See also RFC 4942, Section 2.1.9.5. 159 */ 160 padlen += optlen; 161 if (padlen > 7) 162 goto bad; 163 /* RFC 4942 recommends receiving hosts to 164 * actively check PadN payload to contain 165 * only zeroes. 166 */ 167 for (i = 2; i < optlen; i++) { 168 if (nh[off + i] != 0) 169 goto bad; 170 } 171 } else { 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 } 192 off += optlen; 193 len -= optlen; 194 } 195 196 if (len == 0) 197 return true; 198bad: 199 kfree_skb(skb); 200 return false; 201} 202 203/***************************** 204 Destination options header. 205 *****************************/ 206 207#if IS_ENABLED(CONFIG_IPV6_MIP6) 208static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 209{ 210 struct ipv6_destopt_hao *hao; 211 struct inet6_skb_parm *opt = IP6CB(skb); 212 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 213 int ret; 214 215 if (opt->dsthao) { 216 net_dbg_ratelimited("hao duplicated\n"); 217 goto discard; 218 } 219 opt->dsthao = opt->dst1; 220 opt->dst1 = 0; 221 222 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 223 224 if (hao->length != 16) { 225 net_dbg_ratelimited("hao invalid option length = %d\n", 226 hao->length); 227 goto discard; 228 } 229 230 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 231 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 232 &hao->addr); 233 goto discard; 234 } 235 236 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 237 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 238 if (unlikely(ret < 0)) 239 goto discard; 240 241 if (skb_cloned(skb)) { 242 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 243 goto discard; 244 245 /* update all variable using below by copied skbuff */ 246 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 247 optoff); 248 ipv6h = ipv6_hdr(skb); 249 } 250 251 if (skb->ip_summed == CHECKSUM_COMPLETE) 252 skb->ip_summed = CHECKSUM_NONE; 253 254 swap(ipv6h->saddr, hao->addr); 255 256 if (skb->tstamp == 0) 257 __net_timestamp(skb); 258 259 return true; 260 261 discard: 262 kfree_skb(skb); 263 return false; 264} 265#endif 266 267static const struct tlvtype_proc tlvprocdestopt_lst[] = { 268#if IS_ENABLED(CONFIG_IPV6_MIP6) 269 { 270 .type = IPV6_TLV_HAO, 271 .func = ipv6_dest_hao, 272 }, 273#endif 274 {-1, NULL} 275}; 276 277static int ipv6_destopt_rcv(struct sk_buff *skb) 278{ 279 struct inet6_dev *idev = __in6_dev_get(skb->dev); 280 struct inet6_skb_parm *opt = IP6CB(skb); 281#if IS_ENABLED(CONFIG_IPV6_MIP6) 282 __u16 dstbuf; 283#endif 284 struct dst_entry *dst = skb_dst(skb); 285 struct net *net = dev_net(skb->dev); 286 int extlen; 287 288 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 289 !pskb_may_pull(skb, (skb_transport_offset(skb) + 290 ((skb_transport_header(skb)[1] + 1) << 3)))) { 291 __IP6_INC_STATS(dev_net(dst->dev), idev, 292 IPSTATS_MIB_INHDRERRORS); 293fail_and_free: 294 kfree_skb(skb); 295 return -1; 296 } 297 298 extlen = (skb_transport_header(skb)[1] + 1) << 3; 299 if (extlen > net->ipv6.sysctl.max_dst_opts_len) 300 goto fail_and_free; 301 302 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 303#if IS_ENABLED(CONFIG_IPV6_MIP6) 304 dstbuf = opt->dst1; 305#endif 306 307 if (ip6_parse_tlv(tlvprocdestopt_lst, skb, 308 net->ipv6.sysctl.max_dst_opts_cnt)) { 309 skb->transport_header += extlen; 310 opt = IP6CB(skb); 311#if IS_ENABLED(CONFIG_IPV6_MIP6) 312 opt->nhoff = dstbuf; 313#else 314 opt->nhoff = opt->dst1; 315#endif 316 return 1; 317 } 318 319 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 320 return -1; 321} 322 323static void seg6_update_csum(struct sk_buff *skb) 324{ 325 struct ipv6_sr_hdr *hdr; 326 struct in6_addr *addr; 327 __be32 from, to; 328 329 /* srh is at transport offset and seg_left is already decremented 330 * but daddr is not yet updated with next segment 331 */ 332 333 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 334 addr = hdr->segments + hdr->segments_left; 335 336 hdr->segments_left++; 337 from = *(__be32 *)hdr; 338 339 hdr->segments_left--; 340 to = *(__be32 *)hdr; 341 342 /* update skb csum with diff resulting from seg_left decrement */ 343 344 update_csum_diff4(skb, from, to); 345 346 /* compute csum diff between current and next segment and update */ 347 348 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 349 (__be32 *)addr); 350} 351 352static int ipv6_srh_rcv(struct sk_buff *skb) 353{ 354 struct inet6_skb_parm *opt = IP6CB(skb); 355 struct net *net = dev_net(skb->dev); 356 struct ipv6_sr_hdr *hdr; 357 struct inet6_dev *idev; 358 struct in6_addr *addr; 359 int accept_seg6; 360 361 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 362 363 idev = __in6_dev_get(skb->dev); 364 365 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 366 if (accept_seg6 > idev->cnf.seg6_enabled) 367 accept_seg6 = idev->cnf.seg6_enabled; 368 369 if (!accept_seg6) { 370 kfree_skb(skb); 371 return -1; 372 } 373 374#ifdef CONFIG_IPV6_SEG6_HMAC 375 if (!seg6_hmac_validate_skb(skb)) { 376 kfree_skb(skb); 377 return -1; 378 } 379#endif 380 381looped_back: 382 if (hdr->segments_left == 0) { 383 if (hdr->nexthdr == NEXTHDR_IPV6) { 384 int offset = (hdr->hdrlen + 1) << 3; 385 386 skb_postpull_rcsum(skb, skb_network_header(skb), 387 skb_network_header_len(skb)); 388 389 if (!pskb_pull(skb, offset)) { 390 kfree_skb(skb); 391 return -1; 392 } 393 skb_postpull_rcsum(skb, skb_transport_header(skb), 394 offset); 395 396 skb_reset_network_header(skb); 397 skb_reset_transport_header(skb); 398 skb->encapsulation = 0; 399 400 __skb_tunnel_rx(skb, skb->dev, net); 401 402 netif_rx(skb); 403 return -1; 404 } 405 406 opt->srcrt = skb_network_header_len(skb); 407 opt->lastopt = opt->srcrt; 408 skb->transport_header += (hdr->hdrlen + 1) << 3; 409 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 410 411 return 1; 412 } 413 414 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 415 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 416 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 417 ((&hdr->segments_left) - 418 skb_network_header(skb))); 419 return -1; 420 } 421 422 if (skb_cloned(skb)) { 423 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 424 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 425 IPSTATS_MIB_OUTDISCARDS); 426 kfree_skb(skb); 427 return -1; 428 } 429 } 430 431 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 432 433 hdr->segments_left--; 434 addr = hdr->segments + hdr->segments_left; 435 436 skb_push(skb, sizeof(struct ipv6hdr)); 437 438 if (skb->ip_summed == CHECKSUM_COMPLETE) 439 seg6_update_csum(skb); 440 441 ipv6_hdr(skb)->daddr = *addr; 442 443 skb_dst_drop(skb); 444 445 ip6_route_input(skb); 446 447 if (skb_dst(skb)->error) { 448 dst_input(skb); 449 return -1; 450 } 451 452 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 453 if (ipv6_hdr(skb)->hop_limit <= 1) { 454 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 455 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 456 ICMPV6_EXC_HOPLIMIT, 0); 457 kfree_skb(skb); 458 return -1; 459 } 460 ipv6_hdr(skb)->hop_limit--; 461 462 skb_pull(skb, sizeof(struct ipv6hdr)); 463 goto looped_back; 464 } 465 466 dst_input(skb); 467 468 return -1; 469} 470 471static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 472{ 473 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 474 struct inet6_skb_parm *opt = IP6CB(skb); 475 struct net *net = dev_net(skb->dev); 476 struct inet6_dev *idev; 477 struct ipv6hdr *oldhdr; 478 struct in6_addr addr; 479 unsigned char *buf; 480 int accept_rpl_seg; 481 int i, err; 482 u64 n = 0; 483 u32 r; 484 485 idev = __in6_dev_get(skb->dev); 486 487 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled; 488 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled) 489 accept_rpl_seg = idev->cnf.rpl_seg_enabled; 490 491 if (!accept_rpl_seg) { 492 kfree_skb(skb); 493 return -1; 494 } 495 496looped_back: 497 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 498 499 if (hdr->segments_left == 0) { 500 if (hdr->nexthdr == NEXTHDR_IPV6) { 501 int offset = (hdr->hdrlen + 1) << 3; 502 503 skb_postpull_rcsum(skb, skb_network_header(skb), 504 skb_network_header_len(skb)); 505 506 if (!pskb_pull(skb, offset)) { 507 kfree_skb(skb); 508 return -1; 509 } 510 skb_postpull_rcsum(skb, skb_transport_header(skb), 511 offset); 512 513 skb_reset_network_header(skb); 514 skb_reset_transport_header(skb); 515 skb->encapsulation = 0; 516 517 __skb_tunnel_rx(skb, skb->dev, net); 518 519 netif_rx(skb); 520 return -1; 521 } 522 523 opt->srcrt = skb_network_header_len(skb); 524 opt->lastopt = opt->srcrt; 525 skb->transport_header += (hdr->hdrlen + 1) << 3; 526 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 527 528 return 1; 529 } 530 531 if (!pskb_may_pull(skb, sizeof(*hdr))) { 532 kfree_skb(skb); 533 return -1; 534 } 535 536 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 537 r = do_div(n, (16 - hdr->cmpri)); 538 /* checks if calculation was without remainder and n fits into 539 * unsigned char which is segments_left field. Should not be 540 * higher than that. 541 */ 542 if (r || (n + 1) > 255) { 543 kfree_skb(skb); 544 return -1; 545 } 546 547 if (hdr->segments_left > n + 1) { 548 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 549 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 550 ((&hdr->segments_left) - 551 skb_network_header(skb))); 552 return -1; 553 } 554 555 if (!pskb_may_pull(skb, ipv6_rpl_srh_size(n, hdr->cmpri, 556 hdr->cmpre))) { 557 kfree_skb(skb); 558 return -1; 559 } 560 561 hdr->segments_left--; 562 i = n - hdr->segments_left; 563 564 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 565 if (unlikely(!buf)) { 566 kfree_skb(skb); 567 return -1; 568 } 569 570 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 571 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 572 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 573 574 if ((ipv6_addr_type(&ipv6_hdr(skb)->daddr) & IPV6_ADDR_MULTICAST) || 575 (ipv6_addr_type(&ohdr->rpl_segaddr[i]) & IPV6_ADDR_MULTICAST)) { 576 kfree_skb(skb); 577 kfree(buf); 578 return -1; 579 } 580 581 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 582 if (err) { 583 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 584 kfree_skb(skb); 585 kfree(buf); 586 return -1; 587 } 588 589 addr = ipv6_hdr(skb)->daddr; 590 ipv6_hdr(skb)->daddr = ohdr->rpl_segaddr[i]; 591 ohdr->rpl_segaddr[i] = addr; 592 593 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 594 595 oldhdr = ipv6_hdr(skb); 596 597 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 598 skb_postpull_rcsum(skb, oldhdr, 599 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 600 if (unlikely(!hdr->segments_left)) { 601 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, 602 GFP_ATOMIC)) { 603 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 604 kfree_skb(skb); 605 kfree(buf); 606 return -1; 607 } 608 609 oldhdr = ipv6_hdr(skb); 610 } 611 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 612 skb_reset_network_header(skb); 613 skb_mac_header_rebuild(skb); 614 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 615 616 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 617 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 618 619 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 620 skb_postpush_rcsum(skb, ipv6_hdr(skb), 621 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 622 623 kfree(buf); 624 625 skb_dst_drop(skb); 626 627 ip6_route_input(skb); 628 629 if (skb_dst(skb)->error) { 630 dst_input(skb); 631 return -1; 632 } 633 634 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 635 if (ipv6_hdr(skb)->hop_limit <= 1) { 636 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 637 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 638 ICMPV6_EXC_HOPLIMIT, 0); 639 kfree_skb(skb); 640 return -1; 641 } 642 ipv6_hdr(skb)->hop_limit--; 643 644 skb_pull(skb, sizeof(struct ipv6hdr)); 645 goto looped_back; 646 } 647 648 dst_input(skb); 649 650 return -1; 651} 652 653/******************************** 654 Routing header. 655 ********************************/ 656 657/* called with rcu_read_lock() */ 658static int ipv6_rthdr_rcv(struct sk_buff *skb) 659{ 660 struct inet6_dev *idev = __in6_dev_get(skb->dev); 661 struct inet6_skb_parm *opt = IP6CB(skb); 662 struct in6_addr *addr = NULL; 663 struct in6_addr daddr; 664 int n, i; 665 struct ipv6_rt_hdr *hdr; 666 struct rt0_hdr *rthdr; 667 struct net *net = dev_net(skb->dev); 668 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 669 670 idev = __in6_dev_get(skb->dev); 671 if (idev && accept_source_route > idev->cnf.accept_source_route) 672 accept_source_route = idev->cnf.accept_source_route; 673 674 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 675 !pskb_may_pull(skb, (skb_transport_offset(skb) + 676 ((skb_transport_header(skb)[1] + 1) << 3)))) { 677 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 678 kfree_skb(skb); 679 return -1; 680 } 681 682 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 683 684 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 685 skb->pkt_type != PACKET_HOST) { 686 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 687 kfree_skb(skb); 688 return -1; 689 } 690 691 switch (hdr->type) { 692 case IPV6_SRCRT_TYPE_4: 693 /* segment routing */ 694 return ipv6_srh_rcv(skb); 695 case IPV6_SRCRT_TYPE_3: 696 /* rpl segment routing */ 697 return ipv6_rpl_srh_rcv(skb); 698 default: 699 break; 700 } 701 702looped_back: 703 if (hdr->segments_left == 0) { 704 switch (hdr->type) { 705#if IS_ENABLED(CONFIG_IPV6_MIP6) 706 case IPV6_SRCRT_TYPE_2: 707 /* Silently discard type 2 header unless it was 708 * processed by own 709 */ 710 if (!addr) { 711 __IP6_INC_STATS(net, idev, 712 IPSTATS_MIB_INADDRERRORS); 713 kfree_skb(skb); 714 return -1; 715 } 716 break; 717#endif 718 default: 719 break; 720 } 721 722 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 723 skb->transport_header += (hdr->hdrlen + 1) << 3; 724 opt->dst0 = opt->dst1; 725 opt->dst1 = 0; 726 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 727 return 1; 728 } 729 730 switch (hdr->type) { 731#if IS_ENABLED(CONFIG_IPV6_MIP6) 732 case IPV6_SRCRT_TYPE_2: 733 if (accept_source_route < 0) 734 goto unknown_rh; 735 /* Silently discard invalid RTH type 2 */ 736 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 737 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 738 kfree_skb(skb); 739 return -1; 740 } 741 break; 742#endif 743 default: 744 goto unknown_rh; 745 } 746 747 /* 748 * This is the routing header forwarding algorithm from 749 * RFC 2460, page 16. 750 */ 751 752 n = hdr->hdrlen >> 1; 753 754 if (hdr->segments_left > n) { 755 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 756 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 757 ((&hdr->segments_left) - 758 skb_network_header(skb))); 759 return -1; 760 } 761 762 /* We are about to mangle packet header. Be careful! 763 Do not damage packets queued somewhere. 764 */ 765 if (skb_cloned(skb)) { 766 /* the copy is a forwarded packet */ 767 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 768 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 769 IPSTATS_MIB_OUTDISCARDS); 770 kfree_skb(skb); 771 return -1; 772 } 773 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 774 } 775 776 if (skb->ip_summed == CHECKSUM_COMPLETE) 777 skb->ip_summed = CHECKSUM_NONE; 778 779 i = n - --hdr->segments_left; 780 781 rthdr = (struct rt0_hdr *) hdr; 782 addr = rthdr->addr; 783 addr += i - 1; 784 785 switch (hdr->type) { 786#if IS_ENABLED(CONFIG_IPV6_MIP6) 787 case IPV6_SRCRT_TYPE_2: 788 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 789 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 790 IPPROTO_ROUTING) < 0) { 791 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 792 kfree_skb(skb); 793 return -1; 794 } 795 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 796 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 797 kfree_skb(skb); 798 return -1; 799 } 800 break; 801#endif 802 default: 803 break; 804 } 805 806 if (ipv6_addr_is_multicast(addr)) { 807 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 808 kfree_skb(skb); 809 return -1; 810 } 811 812 daddr = *addr; 813 *addr = ipv6_hdr(skb)->daddr; 814 ipv6_hdr(skb)->daddr = daddr; 815 816 skb_dst_drop(skb); 817 ip6_route_input(skb); 818 if (skb_dst(skb)->error) { 819 skb_push(skb, skb->data - skb_network_header(skb)); 820 dst_input(skb); 821 return -1; 822 } 823 824 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 825 if (ipv6_hdr(skb)->hop_limit <= 1) { 826 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 827 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 828 0); 829 kfree_skb(skb); 830 return -1; 831 } 832 ipv6_hdr(skb)->hop_limit--; 833 goto looped_back; 834 } 835 836 skb_push(skb, skb->data - skb_network_header(skb)); 837 dst_input(skb); 838 return -1; 839 840unknown_rh: 841 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 842 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 843 (&hdr->type) - skb_network_header(skb)); 844 return -1; 845} 846 847static const struct inet6_protocol rthdr_protocol = { 848 .handler = ipv6_rthdr_rcv, 849 .flags = INET6_PROTO_NOPOLICY, 850}; 851 852static const struct inet6_protocol destopt_protocol = { 853 .handler = ipv6_destopt_rcv, 854 .flags = INET6_PROTO_NOPOLICY, 855}; 856 857static const struct inet6_protocol nodata_protocol = { 858 .handler = dst_discard, 859 .flags = INET6_PROTO_NOPOLICY, 860}; 861 862int __init ipv6_exthdrs_init(void) 863{ 864 int ret; 865 866 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 867 if (ret) 868 goto out; 869 870 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 871 if (ret) 872 goto out_rthdr; 873 874 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 875 if (ret) 876 goto out_destopt; 877 878out: 879 return ret; 880out_destopt: 881 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 882out_rthdr: 883 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 884 goto out; 885}; 886 887void ipv6_exthdrs_exit(void) 888{ 889 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 890 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 891 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 892} 893 894/********************************** 895 Hop-by-hop options. 896 **********************************/ 897 898/* 899 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 900 */ 901static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 902{ 903 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 904} 905 906static inline struct net *ipv6_skb_net(struct sk_buff *skb) 907{ 908 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 909} 910 911/* Router Alert as of RFC 2711 */ 912 913static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 914{ 915 const unsigned char *nh = skb_network_header(skb); 916 917 if (nh[optoff + 1] == 2) { 918 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 919 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 920 return true; 921 } 922 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 923 nh[optoff + 1]); 924 kfree_skb(skb); 925 return false; 926} 927 928/* Jumbo payload */ 929 930static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 931{ 932 const unsigned char *nh = skb_network_header(skb); 933 struct inet6_dev *idev = __in6_dev_get_safely(skb->dev); 934 struct net *net = ipv6_skb_net(skb); 935 u32 pkt_len; 936 937 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 938 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 939 nh[optoff+1]); 940 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 941 goto drop; 942 } 943 944 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 945 if (pkt_len <= IPV6_MAXPLEN) { 946 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 947 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 948 return false; 949 } 950 if (ipv6_hdr(skb)->payload_len) { 951 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 952 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 953 return false; 954 } 955 956 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 957 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INTRUNCATEDPKTS); 958 goto drop; 959 } 960 961 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 962 goto drop; 963 964 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 965 return true; 966 967drop: 968 kfree_skb(skb); 969 return false; 970} 971 972/* CALIPSO RFC 5570 */ 973 974static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 975{ 976 const unsigned char *nh = skb_network_header(skb); 977 978 if (nh[optoff + 1] < 8) 979 goto drop; 980 981 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 982 goto drop; 983 984 if (!calipso_validate(skb, nh + optoff)) 985 goto drop; 986 987 return true; 988 989drop: 990 kfree_skb(skb); 991 return false; 992} 993 994static const struct tlvtype_proc tlvprochopopt_lst[] = { 995 { 996 .type = IPV6_TLV_ROUTERALERT, 997 .func = ipv6_hop_ra, 998 }, 999 { 1000 .type = IPV6_TLV_JUMBO, 1001 .func = ipv6_hop_jumbo, 1002 }, 1003 { 1004 .type = IPV6_TLV_CALIPSO, 1005 .func = ipv6_hop_calipso, 1006 }, 1007 { -1, } 1008}; 1009 1010int ipv6_parse_hopopts(struct sk_buff *skb) 1011{ 1012 struct inet6_skb_parm *opt = IP6CB(skb); 1013 struct net *net = dev_net(skb->dev); 1014 int extlen; 1015 1016 /* 1017 * skb_network_header(skb) is equal to skb->data, and 1018 * skb_network_header_len(skb) is always equal to 1019 * sizeof(struct ipv6hdr) by definition of 1020 * hop-by-hop options. 1021 */ 1022 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1023 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1024 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1025fail_and_free: 1026 kfree_skb(skb); 1027 return -1; 1028 } 1029 1030 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1031 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 1032 goto fail_and_free; 1033 1034 opt->flags |= IP6SKB_HOPBYHOP; 1035 if (ip6_parse_tlv(tlvprochopopt_lst, skb, 1036 net->ipv6.sysctl.max_hbh_opts_cnt)) { 1037 skb->transport_header += extlen; 1038 opt = IP6CB(skb); 1039 opt->nhoff = sizeof(struct ipv6hdr); 1040 return 1; 1041 } 1042 return -1; 1043} 1044 1045/* 1046 * Creating outbound headers. 1047 * 1048 * "build" functions work when skb is filled from head to tail (datagram) 1049 * "push" functions work when headers are added from tail to head (tcp) 1050 * 1051 * In both cases we assume, that caller reserved enough room 1052 * for headers. 1053 */ 1054 1055static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1056 struct ipv6_rt_hdr *opt, 1057 struct in6_addr **addr_p, struct in6_addr *saddr) 1058{ 1059 struct rt0_hdr *phdr, *ihdr; 1060 int hops; 1061 1062 ihdr = (struct rt0_hdr *) opt; 1063 1064 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1065 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1066 1067 hops = ihdr->rt_hdr.hdrlen >> 1; 1068 1069 if (hops > 1) 1070 memcpy(phdr->addr, ihdr->addr + 1, 1071 (hops - 1) * sizeof(struct in6_addr)); 1072 1073 phdr->addr[hops - 1] = **addr_p; 1074 *addr_p = ihdr->addr; 1075 1076 phdr->rt_hdr.nexthdr = *proto; 1077 *proto = NEXTHDR_ROUTING; 1078} 1079 1080static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1081 struct ipv6_rt_hdr *opt, 1082 struct in6_addr **addr_p, struct in6_addr *saddr) 1083{ 1084 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1085 int plen, hops; 1086 1087 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1088 plen = (sr_ihdr->hdrlen + 1) << 3; 1089 1090 sr_phdr = skb_push(skb, plen); 1091 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1092 1093 hops = sr_ihdr->first_segment + 1; 1094 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1095 (hops - 1) * sizeof(struct in6_addr)); 1096 1097 sr_phdr->segments[0] = **addr_p; 1098 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1099 1100 if (sr_ihdr->hdrlen > hops * 2) { 1101 int tlvs_offset, tlvs_length; 1102 1103 tlvs_offset = (1 + hops * 2) << 3; 1104 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1105 memcpy((char *)sr_phdr + tlvs_offset, 1106 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1107 } 1108 1109#ifdef CONFIG_IPV6_SEG6_HMAC 1110 if (sr_has_hmac(sr_phdr)) { 1111 struct net *net = NULL; 1112 1113 if (skb->dev) 1114 net = dev_net(skb->dev); 1115 else if (skb->sk) 1116 net = sock_net(skb->sk); 1117 1118 WARN_ON(!net); 1119 1120 if (net) 1121 seg6_push_hmac(net, saddr, sr_phdr); 1122 } 1123#endif 1124 1125 sr_phdr->nexthdr = *proto; 1126 *proto = NEXTHDR_ROUTING; 1127} 1128 1129static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1130 struct ipv6_rt_hdr *opt, 1131 struct in6_addr **addr_p, struct in6_addr *saddr) 1132{ 1133 switch (opt->type) { 1134 case IPV6_SRCRT_TYPE_0: 1135 case IPV6_SRCRT_STRICT: 1136 case IPV6_SRCRT_TYPE_2: 1137 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1138 break; 1139 case IPV6_SRCRT_TYPE_4: 1140 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1141 break; 1142 default: 1143 break; 1144 } 1145} 1146 1147static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1148{ 1149 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1150 1151 memcpy(h, opt, ipv6_optlen(opt)); 1152 h->nexthdr = *proto; 1153 *proto = type; 1154} 1155 1156void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1157 u8 *proto, 1158 struct in6_addr **daddr, struct in6_addr *saddr) 1159{ 1160 if (opt->srcrt) { 1161 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1162 /* 1163 * IPV6_RTHDRDSTOPTS is ignored 1164 * unless IPV6_RTHDR is set (RFC3542). 1165 */ 1166 if (opt->dst0opt) 1167 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1168 } 1169 if (opt->hopopt) 1170 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1171} 1172 1173void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1174{ 1175 if (opt->dst1opt) 1176 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1177} 1178EXPORT_SYMBOL(ipv6_push_frag_opts); 1179 1180struct ipv6_txoptions * 1181ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1182{ 1183 struct ipv6_txoptions *opt2; 1184 1185 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 1186 if (opt2) { 1187 long dif = (char *)opt2 - (char *)opt; 1188 memcpy(opt2, opt, opt->tot_len); 1189 if (opt2->hopopt) 1190 *((char **)&opt2->hopopt) += dif; 1191 if (opt2->dst0opt) 1192 *((char **)&opt2->dst0opt) += dif; 1193 if (opt2->dst1opt) 1194 *((char **)&opt2->dst1opt) += dif; 1195 if (opt2->srcrt) 1196 *((char **)&opt2->srcrt) += dif; 1197 refcount_set(&opt2->refcnt, 1); 1198 } 1199 return opt2; 1200} 1201EXPORT_SYMBOL_GPL(ipv6_dup_options); 1202 1203static void ipv6_renew_option(int renewtype, 1204 struct ipv6_opt_hdr **dest, 1205 struct ipv6_opt_hdr *old, 1206 struct ipv6_opt_hdr *new, 1207 int newtype, char **p) 1208{ 1209 struct ipv6_opt_hdr *src; 1210 1211 src = (renewtype == newtype ? new : old); 1212 if (!src) 1213 return; 1214 1215 memcpy(*p, src, ipv6_optlen(src)); 1216 *dest = (struct ipv6_opt_hdr *)*p; 1217 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1218} 1219 1220/** 1221 * ipv6_renew_options - replace a specific ext hdr with a new one. 1222 * 1223 * @sk: sock from which to allocate memory 1224 * @opt: original options 1225 * @newtype: option type to replace in @opt 1226 * @newopt: new option of type @newtype to replace (user-mem) 1227 * 1228 * Returns a new set of options which is a copy of @opt with the 1229 * option type @newtype replaced with @newopt. 1230 * 1231 * @opt may be NULL, in which case a new set of options is returned 1232 * containing just @newopt. 1233 * 1234 * @newopt may be NULL, in which case the specified option type is 1235 * not copied into the new set of options. 1236 * 1237 * The new set of options is allocated from the socket option memory 1238 * buffer of @sk. 1239 */ 1240struct ipv6_txoptions * 1241ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1242 int newtype, struct ipv6_opt_hdr *newopt) 1243{ 1244 int tot_len = 0; 1245 char *p; 1246 struct ipv6_txoptions *opt2; 1247 1248 if (opt) { 1249 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1250 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1251 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1252 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1253 if (newtype != IPV6_RTHDR && opt->srcrt) 1254 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1255 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1256 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1257 } 1258 1259 if (newopt) 1260 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1261 1262 if (!tot_len) 1263 return NULL; 1264 1265 tot_len += sizeof(*opt2); 1266 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1267 if (!opt2) 1268 return ERR_PTR(-ENOBUFS); 1269 1270 memset(opt2, 0, tot_len); 1271 refcount_set(&opt2->refcnt, 1); 1272 opt2->tot_len = tot_len; 1273 p = (char *)(opt2 + 1); 1274 1275 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1276 (opt ? opt->hopopt : NULL), 1277 newopt, newtype, &p); 1278 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1279 (opt ? opt->dst0opt : NULL), 1280 newopt, newtype, &p); 1281 ipv6_renew_option(IPV6_RTHDR, 1282 (struct ipv6_opt_hdr **)&opt2->srcrt, 1283 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1284 newopt, newtype, &p); 1285 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1286 (opt ? opt->dst1opt : NULL), 1287 newopt, newtype, &p); 1288 1289 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1290 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1291 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1292 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1293 1294 return opt2; 1295} 1296 1297struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1298 struct ipv6_txoptions *opt) 1299{ 1300 /* 1301 * ignore the dest before srcrt unless srcrt is being included. 1302 * --yoshfuji 1303 */ 1304 if (opt && opt->dst0opt && !opt->srcrt) { 1305 if (opt_space != opt) { 1306 memcpy(opt_space, opt, sizeof(*opt_space)); 1307 opt = opt_space; 1308 } 1309 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1310 opt->dst0opt = NULL; 1311 } 1312 1313 return opt; 1314} 1315EXPORT_SYMBOL_GPL(ipv6_fixup_options); 1316 1317/** 1318 * fl6_update_dst - update flowi destination address with info given 1319 * by srcrt option, if any. 1320 * 1321 * @fl6: flowi6 for which daddr is to be updated 1322 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1323 * @orig: copy of original daddr address if modified 1324 * 1325 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1326 * and initial value of fl6->daddr set in orig 1327 */ 1328struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1329 const struct ipv6_txoptions *opt, 1330 struct in6_addr *orig) 1331{ 1332 if (!opt || !opt->srcrt) 1333 return NULL; 1334 1335 *orig = fl6->daddr; 1336 1337 switch (opt->srcrt->type) { 1338 case IPV6_SRCRT_TYPE_0: 1339 case IPV6_SRCRT_STRICT: 1340 case IPV6_SRCRT_TYPE_2: 1341 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1342 break; 1343 case IPV6_SRCRT_TYPE_4: 1344 { 1345 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1346 1347 fl6->daddr = srh->segments[srh->segments_left]; 1348 break; 1349 } 1350 default: 1351 return NULL; 1352 } 1353 1354 return orig; 1355} 1356EXPORT_SYMBOL_GPL(fl6_update_dst); 1357