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_reason(skb, ICMPV6_UNK_OPTION, optoff, 94 SKB_DROP_REASON_UNHANDLED_PROTO); 95 return false; 96 } 97 98 drop: 99 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO); 100 return false; 101 } 102 103 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff); 104 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff); 105 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff); 106 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff); 107 #if IS_ENABLED(CONFIG_IPV6_MIP6) 108 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff); 109 #endif 110 111 /* Parse tlv encoded option header (hop-by-hop or destination) */ 112 113 static bool ip6_parse_tlv(bool hopbyhop, 114 struct sk_buff *skb, 115 int max_count) 116 { 117 int len = (skb_transport_header(skb)[1] + 1) << 3; 118 const unsigned char *nh = skb_network_header(skb); 119 int off = skb_network_header_len(skb); 120 bool disallow_unknowns = false; 121 int tlv_count = 0; 122 int padlen = 0; 123 124 if (unlikely(max_count < 0)) { 125 disallow_unknowns = true; 126 max_count = -max_count; 127 } 128 129 off += 2; 130 len -= 2; 131 132 while (len > 0) { 133 int optlen, i; 134 135 if (nh[off] == IPV6_TLV_PAD1) { 136 padlen++; 137 if (padlen > 7) 138 goto bad; 139 off++; 140 len--; 141 continue; 142 } 143 if (len < 2) 144 goto bad; 145 optlen = nh[off + 1] + 2; 146 if (optlen > len) 147 goto bad; 148 149 if (nh[off] == 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 } else { 167 tlv_count++; 168 if (tlv_count > max_count) 169 goto bad; 170 171 if (hopbyhop) { 172 switch (nh[off]) { 173 case IPV6_TLV_ROUTERALERT: 174 if (!ipv6_hop_ra(skb, off)) 175 return false; 176 break; 177 case IPV6_TLV_IOAM: 178 if (!ipv6_hop_ioam(skb, off)) 179 return false; 180 break; 181 case IPV6_TLV_JUMBO: 182 if (!ipv6_hop_jumbo(skb, off)) 183 return false; 184 break; 185 case IPV6_TLV_CALIPSO: 186 if (!ipv6_hop_calipso(skb, off)) 187 return false; 188 break; 189 default: 190 if (!ip6_tlvopt_unknown(skb, off, 191 disallow_unknowns)) 192 return false; 193 break; 194 } 195 } else { 196 switch (nh[off]) { 197 #if IS_ENABLED(CONFIG_IPV6_MIP6) 198 case IPV6_TLV_HAO: 199 if (!ipv6_dest_hao(skb, off)) 200 return false; 201 break; 202 #endif 203 default: 204 if (!ip6_tlvopt_unknown(skb, off, 205 disallow_unknowns)) 206 return false; 207 break; 208 } 209 } 210 padlen = 0; 211 } 212 off += optlen; 213 len -= optlen; 214 } 215 216 if (len == 0) 217 return true; 218 bad: 219 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 220 return false; 221 } 222 223 /***************************** 224 Destination options header. 225 *****************************/ 226 227 #if IS_ENABLED(CONFIG_IPV6_MIP6) 228 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 229 { 230 struct ipv6_destopt_hao *hao; 231 struct inet6_skb_parm *opt = IP6CB(skb); 232 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 233 SKB_DR(reason); 234 int ret; 235 236 if (opt->dsthao) { 237 net_dbg_ratelimited("hao duplicated\n"); 238 goto discard; 239 } 240 opt->dsthao = opt->dst1; 241 opt->dst1 = 0; 242 243 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 244 245 if (hao->length != 16) { 246 net_dbg_ratelimited("hao invalid option length = %d\n", 247 hao->length); 248 SKB_DR_SET(reason, IP_INHDR); 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 SKB_DR_SET(reason, INVALID_PROTO); 256 goto discard; 257 } 258 259 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 260 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 261 if (unlikely(ret < 0)) { 262 SKB_DR_SET(reason, XFRM_POLICY); 263 goto discard; 264 } 265 266 if (skb_cloned(skb)) { 267 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 268 goto discard; 269 270 /* update all variable using below by copied skbuff */ 271 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 272 optoff); 273 ipv6h = ipv6_hdr(skb); 274 } 275 276 if (skb->ip_summed == CHECKSUM_COMPLETE) 277 skb->ip_summed = CHECKSUM_NONE; 278 279 swap(ipv6h->saddr, hao->addr); 280 281 if (skb->tstamp == 0) 282 __net_timestamp(skb); 283 284 return true; 285 286 discard: 287 kfree_skb_reason(skb, reason); 288 return false; 289 } 290 #endif 291 292 static int ipv6_destopt_rcv(struct sk_buff *skb) 293 { 294 struct inet6_dev *idev = __in6_dev_get(skb->dev); 295 struct inet6_skb_parm *opt = IP6CB(skb); 296 #if IS_ENABLED(CONFIG_IPV6_MIP6) 297 __u16 dstbuf; 298 #endif 299 struct dst_entry *dst = skb_dst(skb); 300 struct net *net = dev_net(skb->dev); 301 int extlen; 302 303 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 304 !pskb_may_pull(skb, (skb_transport_offset(skb) + 305 ((skb_transport_header(skb)[1] + 1) << 3)))) { 306 __IP6_INC_STATS(dev_net(dst->dev), idev, 307 IPSTATS_MIB_INHDRERRORS); 308 fail_and_free: 309 kfree_skb(skb); 310 return -1; 311 } 312 313 extlen = (skb_transport_header(skb)[1] + 1) << 3; 314 if (extlen > net->ipv6.sysctl.max_dst_opts_len) 315 goto fail_and_free; 316 317 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 318 #if IS_ENABLED(CONFIG_IPV6_MIP6) 319 dstbuf = opt->dst1; 320 #endif 321 322 if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) { 323 skb->transport_header += extlen; 324 opt = IP6CB(skb); 325 #if IS_ENABLED(CONFIG_IPV6_MIP6) 326 opt->nhoff = dstbuf; 327 #else 328 opt->nhoff = opt->dst1; 329 #endif 330 return 1; 331 } 332 333 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 334 return -1; 335 } 336 337 static void seg6_update_csum(struct sk_buff *skb) 338 { 339 struct ipv6_sr_hdr *hdr; 340 struct in6_addr *addr; 341 __be32 from, to; 342 343 /* srh is at transport offset and seg_left is already decremented 344 * but daddr is not yet updated with next segment 345 */ 346 347 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 348 addr = hdr->segments + hdr->segments_left; 349 350 hdr->segments_left++; 351 from = *(__be32 *)hdr; 352 353 hdr->segments_left--; 354 to = *(__be32 *)hdr; 355 356 /* update skb csum with diff resulting from seg_left decrement */ 357 358 update_csum_diff4(skb, from, to); 359 360 /* compute csum diff between current and next segment and update */ 361 362 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 363 (__be32 *)addr); 364 } 365 366 static int ipv6_srh_rcv(struct sk_buff *skb) 367 { 368 struct inet6_skb_parm *opt = IP6CB(skb); 369 struct net *net = dev_net(skb->dev); 370 struct ipv6_sr_hdr *hdr; 371 struct inet6_dev *idev; 372 struct in6_addr *addr; 373 int accept_seg6; 374 375 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 376 377 idev = __in6_dev_get(skb->dev); 378 379 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 380 if (accept_seg6 > idev->cnf.seg6_enabled) 381 accept_seg6 = idev->cnf.seg6_enabled; 382 383 if (!accept_seg6) { 384 kfree_skb(skb); 385 return -1; 386 } 387 388 #ifdef CONFIG_IPV6_SEG6_HMAC 389 if (!seg6_hmac_validate_skb(skb)) { 390 kfree_skb(skb); 391 return -1; 392 } 393 #endif 394 395 looped_back: 396 if (hdr->segments_left == 0) { 397 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { 398 int offset = (hdr->hdrlen + 1) << 3; 399 400 skb_postpull_rcsum(skb, skb_network_header(skb), 401 skb_network_header_len(skb)); 402 skb_pull(skb, offset); 403 skb_postpull_rcsum(skb, skb_transport_header(skb), 404 offset); 405 406 skb_reset_network_header(skb); 407 skb_reset_transport_header(skb); 408 skb->encapsulation = 0; 409 if (hdr->nexthdr == NEXTHDR_IPV4) 410 skb->protocol = htons(ETH_P_IP); 411 __skb_tunnel_rx(skb, skb->dev, net); 412 413 netif_rx(skb); 414 return -1; 415 } 416 417 opt->srcrt = skb_network_header_len(skb); 418 opt->lastopt = opt->srcrt; 419 skb->transport_header += (hdr->hdrlen + 1) << 3; 420 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 421 422 return 1; 423 } 424 425 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 426 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 427 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 428 ((&hdr->segments_left) - 429 skb_network_header(skb))); 430 return -1; 431 } 432 433 if (skb_cloned(skb)) { 434 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 435 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 436 IPSTATS_MIB_OUTDISCARDS); 437 kfree_skb(skb); 438 return -1; 439 } 440 441 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 442 } 443 444 hdr->segments_left--; 445 addr = hdr->segments + hdr->segments_left; 446 447 skb_push(skb, sizeof(struct ipv6hdr)); 448 449 if (skb->ip_summed == CHECKSUM_COMPLETE) 450 seg6_update_csum(skb); 451 452 ipv6_hdr(skb)->daddr = *addr; 453 454 ip6_route_input(skb); 455 456 if (skb_dst(skb)->error) { 457 dst_input(skb); 458 return -1; 459 } 460 461 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 462 if (ipv6_hdr(skb)->hop_limit <= 1) { 463 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 464 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 465 ICMPV6_EXC_HOPLIMIT, 0); 466 kfree_skb(skb); 467 return -1; 468 } 469 ipv6_hdr(skb)->hop_limit--; 470 471 skb_pull(skb, sizeof(struct ipv6hdr)); 472 goto looped_back; 473 } 474 475 dst_input(skb); 476 477 return -1; 478 } 479 480 static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 481 { 482 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 483 struct inet6_skb_parm *opt = IP6CB(skb); 484 struct net *net = dev_net(skb->dev); 485 struct inet6_dev *idev; 486 struct ipv6hdr *oldhdr; 487 unsigned char *buf; 488 int accept_rpl_seg; 489 int i, err; 490 u64 n = 0; 491 u32 r; 492 493 idev = __in6_dev_get(skb->dev); 494 495 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled; 496 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled) 497 accept_rpl_seg = idev->cnf.rpl_seg_enabled; 498 499 if (!accept_rpl_seg) { 500 kfree_skb(skb); 501 return -1; 502 } 503 504 looped_back: 505 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 506 507 if (hdr->segments_left == 0) { 508 if (hdr->nexthdr == NEXTHDR_IPV6) { 509 int offset = (hdr->hdrlen + 1) << 3; 510 511 skb_postpull_rcsum(skb, skb_network_header(skb), 512 skb_network_header_len(skb)); 513 skb_pull(skb, offset); 514 skb_postpull_rcsum(skb, skb_transport_header(skb), 515 offset); 516 517 skb_reset_network_header(skb); 518 skb_reset_transport_header(skb); 519 skb->encapsulation = 0; 520 521 __skb_tunnel_rx(skb, skb->dev, net); 522 523 netif_rx(skb); 524 return -1; 525 } 526 527 opt->srcrt = skb_network_header_len(skb); 528 opt->lastopt = opt->srcrt; 529 skb->transport_header += (hdr->hdrlen + 1) << 3; 530 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 531 532 return 1; 533 } 534 535 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 536 r = do_div(n, (16 - hdr->cmpri)); 537 /* checks if calculation was without remainder and n fits into 538 * unsigned char which is segments_left field. Should not be 539 * higher than that. 540 */ 541 if (r || (n + 1) > 255) { 542 kfree_skb(skb); 543 return -1; 544 } 545 546 if (hdr->segments_left > n + 1) { 547 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 548 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 549 ((&hdr->segments_left) - 550 skb_network_header(skb))); 551 return -1; 552 } 553 554 hdr->segments_left--; 555 i = n - hdr->segments_left; 556 557 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 558 if (unlikely(!buf)) { 559 kfree_skb(skb); 560 return -1; 561 } 562 563 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 564 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 565 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 566 567 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) { 568 kfree_skb(skb); 569 kfree(buf); 570 return -1; 571 } 572 573 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 574 if (err) { 575 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 576 kfree_skb(skb); 577 kfree(buf); 578 return -1; 579 } 580 581 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); 582 583 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 584 585 oldhdr = ipv6_hdr(skb); 586 587 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 588 skb_postpull_rcsum(skb, oldhdr, 589 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 590 if (unlikely(!hdr->segments_left)) { 591 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, 592 GFP_ATOMIC)) { 593 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 594 kfree_skb(skb); 595 kfree(buf); 596 return -1; 597 } 598 599 oldhdr = ipv6_hdr(skb); 600 } 601 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 602 skb_reset_network_header(skb); 603 skb_mac_header_rebuild(skb); 604 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 605 606 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 607 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 608 609 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 610 skb_postpush_rcsum(skb, ipv6_hdr(skb), 611 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 612 613 kfree(buf); 614 615 ip6_route_input(skb); 616 617 if (skb_dst(skb)->error) { 618 dst_input(skb); 619 return -1; 620 } 621 622 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 623 if (ipv6_hdr(skb)->hop_limit <= 1) { 624 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 625 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 626 ICMPV6_EXC_HOPLIMIT, 0); 627 kfree_skb(skb); 628 return -1; 629 } 630 ipv6_hdr(skb)->hop_limit--; 631 632 skb_pull(skb, sizeof(struct ipv6hdr)); 633 goto looped_back; 634 } 635 636 dst_input(skb); 637 638 return -1; 639 } 640 641 /******************************** 642 Routing header. 643 ********************************/ 644 645 /* called with rcu_read_lock() */ 646 static int ipv6_rthdr_rcv(struct sk_buff *skb) 647 { 648 struct inet6_dev *idev = __in6_dev_get(skb->dev); 649 struct inet6_skb_parm *opt = IP6CB(skb); 650 struct in6_addr *addr = NULL; 651 struct in6_addr daddr; 652 int n, i; 653 struct ipv6_rt_hdr *hdr; 654 struct rt0_hdr *rthdr; 655 struct net *net = dev_net(skb->dev); 656 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 657 658 if (idev && accept_source_route > idev->cnf.accept_source_route) 659 accept_source_route = idev->cnf.accept_source_route; 660 661 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 662 !pskb_may_pull(skb, (skb_transport_offset(skb) + 663 ((skb_transport_header(skb)[1] + 1) << 3)))) { 664 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 665 kfree_skb(skb); 666 return -1; 667 } 668 669 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 670 671 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 672 skb->pkt_type != PACKET_HOST) { 673 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 674 kfree_skb(skb); 675 return -1; 676 } 677 678 switch (hdr->type) { 679 case IPV6_SRCRT_TYPE_4: 680 /* segment routing */ 681 return ipv6_srh_rcv(skb); 682 case IPV6_SRCRT_TYPE_3: 683 /* rpl segment routing */ 684 return ipv6_rpl_srh_rcv(skb); 685 default: 686 break; 687 } 688 689 looped_back: 690 if (hdr->segments_left == 0) { 691 switch (hdr->type) { 692 #if IS_ENABLED(CONFIG_IPV6_MIP6) 693 case IPV6_SRCRT_TYPE_2: 694 /* Silently discard type 2 header unless it was 695 * processed by own 696 */ 697 if (!addr) { 698 __IP6_INC_STATS(net, idev, 699 IPSTATS_MIB_INADDRERRORS); 700 kfree_skb(skb); 701 return -1; 702 } 703 break; 704 #endif 705 default: 706 break; 707 } 708 709 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 710 skb->transport_header += (hdr->hdrlen + 1) << 3; 711 opt->dst0 = opt->dst1; 712 opt->dst1 = 0; 713 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 714 return 1; 715 } 716 717 switch (hdr->type) { 718 #if IS_ENABLED(CONFIG_IPV6_MIP6) 719 case IPV6_SRCRT_TYPE_2: 720 if (accept_source_route < 0) 721 goto unknown_rh; 722 /* Silently discard invalid RTH type 2 */ 723 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 724 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 725 kfree_skb(skb); 726 return -1; 727 } 728 break; 729 #endif 730 default: 731 goto unknown_rh; 732 } 733 734 /* 735 * This is the routing header forwarding algorithm from 736 * RFC 2460, page 16. 737 */ 738 739 n = hdr->hdrlen >> 1; 740 741 if (hdr->segments_left > n) { 742 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 743 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 744 ((&hdr->segments_left) - 745 skb_network_header(skb))); 746 return -1; 747 } 748 749 /* We are about to mangle packet header. Be careful! 750 Do not damage packets queued somewhere. 751 */ 752 if (skb_cloned(skb)) { 753 /* the copy is a forwarded packet */ 754 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 755 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 756 IPSTATS_MIB_OUTDISCARDS); 757 kfree_skb(skb); 758 return -1; 759 } 760 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 761 } 762 763 if (skb->ip_summed == CHECKSUM_COMPLETE) 764 skb->ip_summed = CHECKSUM_NONE; 765 766 i = n - --hdr->segments_left; 767 768 rthdr = (struct rt0_hdr *) hdr; 769 addr = rthdr->addr; 770 addr += i - 1; 771 772 switch (hdr->type) { 773 #if IS_ENABLED(CONFIG_IPV6_MIP6) 774 case IPV6_SRCRT_TYPE_2: 775 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 776 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 777 IPPROTO_ROUTING) < 0) { 778 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 779 kfree_skb(skb); 780 return -1; 781 } 782 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 783 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 784 kfree_skb(skb); 785 return -1; 786 } 787 break; 788 #endif 789 default: 790 break; 791 } 792 793 if (ipv6_addr_is_multicast(addr)) { 794 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 795 kfree_skb(skb); 796 return -1; 797 } 798 799 daddr = *addr; 800 *addr = ipv6_hdr(skb)->daddr; 801 ipv6_hdr(skb)->daddr = daddr; 802 803 ip6_route_input(skb); 804 if (skb_dst(skb)->error) { 805 skb_push(skb, skb->data - skb_network_header(skb)); 806 dst_input(skb); 807 return -1; 808 } 809 810 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 811 if (ipv6_hdr(skb)->hop_limit <= 1) { 812 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 813 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 814 0); 815 kfree_skb(skb); 816 return -1; 817 } 818 ipv6_hdr(skb)->hop_limit--; 819 goto looped_back; 820 } 821 822 skb_push(skb, skb->data - skb_network_header(skb)); 823 dst_input(skb); 824 return -1; 825 826 unknown_rh: 827 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 828 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 829 (&hdr->type) - skb_network_header(skb)); 830 return -1; 831 } 832 833 static const struct inet6_protocol rthdr_protocol = { 834 .handler = ipv6_rthdr_rcv, 835 .flags = INET6_PROTO_NOPOLICY, 836 }; 837 838 static const struct inet6_protocol destopt_protocol = { 839 .handler = ipv6_destopt_rcv, 840 .flags = INET6_PROTO_NOPOLICY, 841 }; 842 843 static const struct inet6_protocol nodata_protocol = { 844 .handler = dst_discard, 845 .flags = INET6_PROTO_NOPOLICY, 846 }; 847 848 int __init ipv6_exthdrs_init(void) 849 { 850 int ret; 851 852 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 853 if (ret) 854 goto out; 855 856 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 857 if (ret) 858 goto out_rthdr; 859 860 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 861 if (ret) 862 goto out_destopt; 863 864 out: 865 return ret; 866 out_destopt: 867 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 868 out_rthdr: 869 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 870 goto out; 871 }; 872 873 void ipv6_exthdrs_exit(void) 874 { 875 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 876 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 877 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 878 } 879 880 /********************************** 881 Hop-by-hop options. 882 **********************************/ 883 884 /* 885 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 886 */ 887 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 888 { 889 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 890 } 891 892 /* Router Alert as of RFC 2711 */ 893 894 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 895 { 896 const unsigned char *nh = skb_network_header(skb); 897 898 if (nh[optoff + 1] == 2) { 899 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 900 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 901 return true; 902 } 903 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 904 nh[optoff + 1]); 905 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 906 return false; 907 } 908 909 /* IOAM */ 910 911 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 912 { 913 struct ioam6_trace_hdr *trace; 914 struct ioam6_namespace *ns; 915 struct ioam6_hdr *hdr; 916 917 /* Bad alignment (must be 4n-aligned) */ 918 if (optoff & 3) 919 goto drop; 920 921 /* Ignore if IOAM is not enabled on ingress */ 922 if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled) 923 goto ignore; 924 925 /* Truncated Option header */ 926 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 927 if (hdr->opt_len < 2) 928 goto drop; 929 930 switch (hdr->type) { 931 case IOAM6_TYPE_PREALLOC: 932 /* Truncated Pre-allocated Trace header */ 933 if (hdr->opt_len < 2 + sizeof(*trace)) 934 goto drop; 935 936 /* Malformed Pre-allocated Trace header */ 937 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 938 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 939 goto drop; 940 941 /* Ignore if the IOAM namespace is unknown */ 942 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id); 943 if (!ns) 944 goto ignore; 945 946 if (!skb_valid_dst(skb)) 947 ip6_route_input(skb); 948 949 ioam6_fill_trace_data(skb, ns, trace, true); 950 break; 951 default: 952 break; 953 } 954 955 ignore: 956 return true; 957 958 drop: 959 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 960 return false; 961 } 962 963 /* Jumbo payload */ 964 965 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 966 { 967 const unsigned char *nh = skb_network_header(skb); 968 SKB_DR(reason); 969 u32 pkt_len; 970 971 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 972 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 973 nh[optoff+1]); 974 SKB_DR_SET(reason, IP_INHDR); 975 goto drop; 976 } 977 978 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 979 if (pkt_len <= IPV6_MAXPLEN) { 980 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 981 SKB_DROP_REASON_IP_INHDR); 982 return false; 983 } 984 if (ipv6_hdr(skb)->payload_len) { 985 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 986 SKB_DROP_REASON_IP_INHDR); 987 return false; 988 } 989 990 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 991 SKB_DR_SET(reason, PKT_TOO_SMALL); 992 goto drop; 993 } 994 995 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 996 goto drop; 997 998 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 999 return true; 1000 1001 drop: 1002 kfree_skb_reason(skb, reason); 1003 return false; 1004 } 1005 1006 /* CALIPSO RFC 5570 */ 1007 1008 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1009 { 1010 const unsigned char *nh = skb_network_header(skb); 1011 1012 if (nh[optoff + 1] < 8) 1013 goto drop; 1014 1015 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1016 goto drop; 1017 1018 if (!calipso_validate(skb, nh + optoff)) 1019 goto drop; 1020 1021 return true; 1022 1023 drop: 1024 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1025 return false; 1026 } 1027 1028 int ipv6_parse_hopopts(struct sk_buff *skb) 1029 { 1030 struct inet6_skb_parm *opt = IP6CB(skb); 1031 struct net *net = dev_net(skb->dev); 1032 int extlen; 1033 1034 /* 1035 * skb_network_header(skb) is equal to skb->data, and 1036 * skb_network_header_len(skb) is always equal to 1037 * sizeof(struct ipv6hdr) by definition of 1038 * hop-by-hop options. 1039 */ 1040 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1041 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1042 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1043 fail_and_free: 1044 kfree_skb(skb); 1045 return -1; 1046 } 1047 1048 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1049 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 1050 goto fail_and_free; 1051 1052 opt->flags |= IP6SKB_HOPBYHOP; 1053 if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) { 1054 skb->transport_header += extlen; 1055 opt = IP6CB(skb); 1056 opt->nhoff = sizeof(struct ipv6hdr); 1057 return 1; 1058 } 1059 return -1; 1060 } 1061 1062 /* 1063 * Creating outbound headers. 1064 * 1065 * "build" functions work when skb is filled from head to tail (datagram) 1066 * "push" functions work when headers are added from tail to head (tcp) 1067 * 1068 * In both cases we assume, that caller reserved enough room 1069 * for headers. 1070 */ 1071 1072 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1073 struct ipv6_rt_hdr *opt, 1074 struct in6_addr **addr_p, struct in6_addr *saddr) 1075 { 1076 struct rt0_hdr *phdr, *ihdr; 1077 int hops; 1078 1079 ihdr = (struct rt0_hdr *) opt; 1080 1081 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1082 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1083 1084 hops = ihdr->rt_hdr.hdrlen >> 1; 1085 1086 if (hops > 1) 1087 memcpy(phdr->addr, ihdr->addr + 1, 1088 (hops - 1) * sizeof(struct in6_addr)); 1089 1090 phdr->addr[hops - 1] = **addr_p; 1091 *addr_p = ihdr->addr; 1092 1093 phdr->rt_hdr.nexthdr = *proto; 1094 *proto = NEXTHDR_ROUTING; 1095 } 1096 1097 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1098 struct ipv6_rt_hdr *opt, 1099 struct in6_addr **addr_p, struct in6_addr *saddr) 1100 { 1101 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1102 int plen, hops; 1103 1104 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1105 plen = (sr_ihdr->hdrlen + 1) << 3; 1106 1107 sr_phdr = skb_push(skb, plen); 1108 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1109 1110 hops = sr_ihdr->first_segment + 1; 1111 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1112 (hops - 1) * sizeof(struct in6_addr)); 1113 1114 sr_phdr->segments[0] = **addr_p; 1115 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1116 1117 if (sr_ihdr->hdrlen > hops * 2) { 1118 int tlvs_offset, tlvs_length; 1119 1120 tlvs_offset = (1 + hops * 2) << 3; 1121 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1122 memcpy((char *)sr_phdr + tlvs_offset, 1123 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1124 } 1125 1126 #ifdef CONFIG_IPV6_SEG6_HMAC 1127 if (sr_has_hmac(sr_phdr)) { 1128 struct net *net = NULL; 1129 1130 if (skb->dev) 1131 net = dev_net(skb->dev); 1132 else if (skb->sk) 1133 net = sock_net(skb->sk); 1134 1135 WARN_ON(!net); 1136 1137 if (net) 1138 seg6_push_hmac(net, saddr, sr_phdr); 1139 } 1140 #endif 1141 1142 sr_phdr->nexthdr = *proto; 1143 *proto = NEXTHDR_ROUTING; 1144 } 1145 1146 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1147 struct ipv6_rt_hdr *opt, 1148 struct in6_addr **addr_p, struct in6_addr *saddr) 1149 { 1150 switch (opt->type) { 1151 case IPV6_SRCRT_TYPE_0: 1152 case IPV6_SRCRT_STRICT: 1153 case IPV6_SRCRT_TYPE_2: 1154 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1155 break; 1156 case IPV6_SRCRT_TYPE_4: 1157 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1158 break; 1159 default: 1160 break; 1161 } 1162 } 1163 1164 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1165 { 1166 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1167 1168 memcpy(h, opt, ipv6_optlen(opt)); 1169 h->nexthdr = *proto; 1170 *proto = type; 1171 } 1172 1173 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1174 u8 *proto, 1175 struct in6_addr **daddr, struct in6_addr *saddr) 1176 { 1177 if (opt->srcrt) { 1178 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1179 /* 1180 * IPV6_RTHDRDSTOPTS is ignored 1181 * unless IPV6_RTHDR is set (RFC3542). 1182 */ 1183 if (opt->dst0opt) 1184 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1185 } 1186 if (opt->hopopt) 1187 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1188 } 1189 1190 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1191 { 1192 if (opt->dst1opt) 1193 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1194 } 1195 EXPORT_SYMBOL(ipv6_push_frag_opts); 1196 1197 struct ipv6_txoptions * 1198 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1199 { 1200 struct ipv6_txoptions *opt2; 1201 1202 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 1203 if (opt2) { 1204 long dif = (char *)opt2 - (char *)opt; 1205 memcpy(opt2, opt, opt->tot_len); 1206 if (opt2->hopopt) 1207 *((char **)&opt2->hopopt) += dif; 1208 if (opt2->dst0opt) 1209 *((char **)&opt2->dst0opt) += dif; 1210 if (opt2->dst1opt) 1211 *((char **)&opt2->dst1opt) += dif; 1212 if (opt2->srcrt) 1213 *((char **)&opt2->srcrt) += dif; 1214 refcount_set(&opt2->refcnt, 1); 1215 } 1216 return opt2; 1217 } 1218 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1219 1220 static void ipv6_renew_option(int renewtype, 1221 struct ipv6_opt_hdr **dest, 1222 struct ipv6_opt_hdr *old, 1223 struct ipv6_opt_hdr *new, 1224 int newtype, char **p) 1225 { 1226 struct ipv6_opt_hdr *src; 1227 1228 src = (renewtype == newtype ? new : old); 1229 if (!src) 1230 return; 1231 1232 memcpy(*p, src, ipv6_optlen(src)); 1233 *dest = (struct ipv6_opt_hdr *)*p; 1234 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1235 } 1236 1237 /** 1238 * ipv6_renew_options - replace a specific ext hdr with a new one. 1239 * 1240 * @sk: sock from which to allocate memory 1241 * @opt: original options 1242 * @newtype: option type to replace in @opt 1243 * @newopt: new option of type @newtype to replace (user-mem) 1244 * 1245 * Returns a new set of options which is a copy of @opt with the 1246 * option type @newtype replaced with @newopt. 1247 * 1248 * @opt may be NULL, in which case a new set of options is returned 1249 * containing just @newopt. 1250 * 1251 * @newopt may be NULL, in which case the specified option type is 1252 * not copied into the new set of options. 1253 * 1254 * The new set of options is allocated from the socket option memory 1255 * buffer of @sk. 1256 */ 1257 struct ipv6_txoptions * 1258 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1259 int newtype, struct ipv6_opt_hdr *newopt) 1260 { 1261 int tot_len = 0; 1262 char *p; 1263 struct ipv6_txoptions *opt2; 1264 1265 if (opt) { 1266 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1267 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1268 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1269 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1270 if (newtype != IPV6_RTHDR && opt->srcrt) 1271 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1272 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1273 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1274 } 1275 1276 if (newopt) 1277 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1278 1279 if (!tot_len) 1280 return NULL; 1281 1282 tot_len += sizeof(*opt2); 1283 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1284 if (!opt2) 1285 return ERR_PTR(-ENOBUFS); 1286 1287 memset(opt2, 0, tot_len); 1288 refcount_set(&opt2->refcnt, 1); 1289 opt2->tot_len = tot_len; 1290 p = (char *)(opt2 + 1); 1291 1292 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1293 (opt ? opt->hopopt : NULL), 1294 newopt, newtype, &p); 1295 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1296 (opt ? opt->dst0opt : NULL), 1297 newopt, newtype, &p); 1298 ipv6_renew_option(IPV6_RTHDR, 1299 (struct ipv6_opt_hdr **)&opt2->srcrt, 1300 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1301 newopt, newtype, &p); 1302 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1303 (opt ? opt->dst1opt : NULL), 1304 newopt, newtype, &p); 1305 1306 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1307 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1308 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1309 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1310 1311 return opt2; 1312 } 1313 1314 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1315 struct ipv6_txoptions *opt) 1316 { 1317 /* 1318 * ignore the dest before srcrt unless srcrt is being included. 1319 * --yoshfuji 1320 */ 1321 if (opt->dst0opt && !opt->srcrt) { 1322 if (opt_space != opt) { 1323 memcpy(opt_space, opt, sizeof(*opt_space)); 1324 opt = opt_space; 1325 } 1326 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1327 opt->dst0opt = NULL; 1328 } 1329 1330 return opt; 1331 } 1332 EXPORT_SYMBOL_GPL(__ipv6_fixup_options); 1333 1334 /** 1335 * fl6_update_dst - update flowi destination address with info given 1336 * by srcrt option, if any. 1337 * 1338 * @fl6: flowi6 for which daddr is to be updated 1339 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1340 * @orig: copy of original daddr address if modified 1341 * 1342 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1343 * and initial value of fl6->daddr set in orig 1344 */ 1345 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1346 const struct ipv6_txoptions *opt, 1347 struct in6_addr *orig) 1348 { 1349 if (!opt || !opt->srcrt) 1350 return NULL; 1351 1352 *orig = fl6->daddr; 1353 1354 switch (opt->srcrt->type) { 1355 case IPV6_SRCRT_TYPE_0: 1356 case IPV6_SRCRT_STRICT: 1357 case IPV6_SRCRT_TYPE_2: 1358 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1359 break; 1360 case IPV6_SRCRT_TYPE_4: 1361 { 1362 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1363 1364 fl6->daddr = srh->segments[srh->segments_left]; 1365 break; 1366 } 1367 default: 1368 return NULL; 1369 } 1370 1371 return orig; 1372 } 1373 EXPORT_SYMBOL_GPL(fl6_update_dst); 1374