FILE
exthdrs.c
File preview with syntax highlighting.
linux-6.19.14/net/ipv6/exthdrs.c
1// SPDX-License-Identifier: GPL-2.0-or-later 2/* 3 * Extension Header handling for IPv6 4 * Linux INET6 implementation 5 * 6 * Authors: 7 * Pedro Roque <roque@di.fc.ul.pt> 8 * Andi Kleen <ak@muc.de> 9 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 10 */ 11 12/* Changes: 13 * yoshfuji : ensure not to overrun while parsing 14 * tlv options. 15 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). 16 * YOSHIFUJI Hideaki @USAGI Register inbound extension header 17 * handlers as inet6_protocol{}. 18 */ 19 20#include <linux/errno.h> 21#include <linux/types.h> 22#include <linux/socket.h> 23#include <linux/sockios.h> 24#include <linux/net.h> 25#include <linux/netdevice.h> 26#include <linux/in6.h> 27#include <linux/icmpv6.h> 28#include <linux/slab.h> 29#include <linux/export.h> 30 31#include <net/dst.h> 32#include <net/sock.h> 33#include <net/snmp.h> 34 35#include <net/ipv6.h> 36#include <net/protocol.h> 37#include <net/transp_v6.h> 38#include <net/rawv6.h> 39#include <net/ndisc.h> 40#include <net/ip6_route.h> 41#include <net/addrconf.h> 42#include <net/calipso.h> 43#if IS_ENABLED(CONFIG_IPV6_MIP6) 44#include <net/xfrm.h> 45#endif 46#include <linux/seg6.h> 47#include <net/seg6.h> 48#ifdef CONFIG_IPV6_SEG6_HMAC 49#include <net/seg6_hmac.h> 50#endif 51#include <net/rpl.h> 52#include <linux/ioam6.h> 53#include <linux/ioam6_genl.h> 54#include <net/ioam6.h> 55#include <net/dst_metadata.h> 56 57#include <linux/uaccess.h> 58 59/********************* 60 Generic functions 61 *********************/ 62 63/* An unknown option is detected, decide what to do */ 64 65static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff, 66 bool disallow_unknowns) 67{ 68 if (disallow_unknowns) { 69 /* If unknown TLVs are disallowed by configuration 70 * then always silently drop packet. Note this also 71 * means no ICMP parameter problem is sent which 72 * could be a good property to mitigate a reflection DOS 73 * attack. 74 */ 75 76 goto drop; 77 } 78 79 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 80 case 0: /* ignore */ 81 return true; 82 83 case 1: /* drop packet */ 84 break; 85 86 case 3: /* Send ICMP if not a multicast address and drop packet */ 87 /* Actually, it is redundant check. icmp_send 88 will recheck in any case. 89 */ 90 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 91 break; 92 fallthrough; 93 case 2: /* send ICMP PARM PROB regardless and drop packet */ 94 icmpv6_param_prob_reason(skb, ICMPV6_UNK_OPTION, optoff, 95 SKB_DROP_REASON_UNHANDLED_PROTO); 96 return false; 97 } 98 99drop: 100 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO); 101 return false; 102} 103 104static bool ipv6_hop_ra(struct sk_buff *skb, int optoff); 105static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff); 106static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff); 107static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff); 108#if IS_ENABLED(CONFIG_IPV6_MIP6) 109static bool ipv6_dest_hao(struct sk_buff *skb, int optoff); 110#endif 111 112/* Parse tlv encoded option header (hop-by-hop or destination) */ 113 114static bool ip6_parse_tlv(bool hopbyhop, 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 bool disallow_unknowns = false; 122 int tlv_count = 0; 123 int padlen = 0; 124 125 if (unlikely(max_count < 0)) { 126 disallow_unknowns = true; 127 max_count = -max_count; 128 } 129 130 off += 2; 131 len -= 2; 132 133 while (len > 0) { 134 int optlen, i; 135 136 if (nh[off] == IPV6_TLV_PAD1) { 137 padlen++; 138 if (padlen > 7) 139 goto bad; 140 off++; 141 len--; 142 continue; 143 } 144 if (len < 2) 145 goto bad; 146 optlen = nh[off + 1] + 2; 147 if (optlen > len) 148 goto bad; 149 150 if (nh[off] == IPV6_TLV_PADN) { 151 /* RFC 2460 states that the purpose of PadN is 152 * to align the containing header to multiples 153 * of 8. 7 is therefore the highest valid value. 154 * See also RFC 4942, Section 2.1.9.5. 155 */ 156 padlen += optlen; 157 if (padlen > 7) 158 goto bad; 159 /* RFC 4942 recommends receiving hosts to 160 * actively check PadN payload to contain 161 * only zeroes. 162 */ 163 for (i = 2; i < optlen; i++) { 164 if (nh[off + i] != 0) 165 goto bad; 166 } 167 } else { 168 tlv_count++; 169 if (tlv_count > max_count) 170 goto bad; 171 172 if (hopbyhop) { 173 switch (nh[off]) { 174 case IPV6_TLV_ROUTERALERT: 175 if (!ipv6_hop_ra(skb, off)) 176 return false; 177 break; 178 case IPV6_TLV_IOAM: 179 if (!ipv6_hop_ioam(skb, off)) 180 return false; 181 182 nh = skb_network_header(skb); 183 break; 184 case IPV6_TLV_JUMBO: 185 if (!ipv6_hop_jumbo(skb, off)) 186 return false; 187 break; 188 case IPV6_TLV_CALIPSO: 189 if (!ipv6_hop_calipso(skb, off)) 190 return false; 191 break; 192 default: 193 if (!ip6_tlvopt_unknown(skb, off, 194 disallow_unknowns)) 195 return false; 196 break; 197 } 198 } else { 199 switch (nh[off]) { 200#if IS_ENABLED(CONFIG_IPV6_MIP6) 201 case IPV6_TLV_HAO: 202 if (!ipv6_dest_hao(skb, off)) 203 return false; 204 break; 205#endif 206 default: 207 if (!ip6_tlvopt_unknown(skb, off, 208 disallow_unknowns)) 209 return false; 210 break; 211 } 212 } 213 padlen = 0; 214 } 215 off += optlen; 216 len -= optlen; 217 } 218 219 if (len == 0) 220 return true; 221bad: 222 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 223 return false; 224} 225 226/***************************** 227 Destination options header. 228 *****************************/ 229 230#if IS_ENABLED(CONFIG_IPV6_MIP6) 231static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 232{ 233 struct ipv6_destopt_hao *hao; 234 struct inet6_skb_parm *opt = IP6CB(skb); 235 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 236 SKB_DR(reason); 237 int ret; 238 239 if (opt->dsthao) { 240 net_dbg_ratelimited("hao duplicated\n"); 241 goto discard; 242 } 243 opt->dsthao = opt->dst1; 244 opt->dst1 = 0; 245 246 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 247 248 if (hao->length != 16) { 249 net_dbg_ratelimited("hao invalid option length = %d\n", 250 hao->length); 251 SKB_DR_SET(reason, IP_INHDR); 252 goto discard; 253 } 254 255 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 256 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 257 &hao->addr); 258 SKB_DR_SET(reason, INVALID_PROTO); 259 goto discard; 260 } 261 262 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 263 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 264 if (unlikely(ret < 0)) { 265 SKB_DR_SET(reason, XFRM_POLICY); 266 goto discard; 267 } 268 269 if (skb_cloned(skb)) { 270 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 271 goto discard; 272 273 /* update all variable using below by copied skbuff */ 274 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 275 optoff); 276 ipv6h = ipv6_hdr(skb); 277 } 278 279 if (skb->ip_summed == CHECKSUM_COMPLETE) 280 skb->ip_summed = CHECKSUM_NONE; 281 282 swap(ipv6h->saddr, hao->addr); 283 284 if (skb->tstamp == 0) 285 __net_timestamp(skb); 286 287 return true; 288 289 discard: 290 kfree_skb_reason(skb, reason); 291 return false; 292} 293#endif 294 295static int ipv6_destopt_rcv(struct sk_buff *skb) 296{ 297 struct inet6_dev *idev = __in6_dev_get(skb->dev); 298 struct inet6_skb_parm *opt = IP6CB(skb); 299#if IS_ENABLED(CONFIG_IPV6_MIP6) 300 __u16 dstbuf; 301#endif 302 struct dst_entry *dst = skb_dst(skb); 303 struct net *net = dev_net(skb->dev); 304 int extlen; 305 306 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 307 !pskb_may_pull(skb, (skb_transport_offset(skb) + 308 ((skb_transport_header(skb)[1] + 1) << 3)))) { 309 __IP6_INC_STATS(dev_net(dst_dev(dst)), idev, 310 IPSTATS_MIB_INHDRERRORS); 311fail_and_free: 312 kfree_skb(skb); 313 return -1; 314 } 315 316 extlen = (skb_transport_header(skb)[1] + 1) << 3; 317 if (extlen > READ_ONCE(net->ipv6.sysctl.max_dst_opts_len)) 318 goto fail_and_free; 319 320 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 321#if IS_ENABLED(CONFIG_IPV6_MIP6) 322 dstbuf = opt->dst1; 323#endif 324 325 if (ip6_parse_tlv(false, skb, 326 READ_ONCE(net->ipv6.sysctl.max_dst_opts_cnt))) { 327 skb->transport_header += extlen; 328 opt = IP6CB(skb); 329#if IS_ENABLED(CONFIG_IPV6_MIP6) 330 opt->nhoff = dstbuf; 331#else 332 opt->nhoff = opt->dst1; 333#endif 334 return 1; 335 } 336 337 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 338 return -1; 339} 340 341static void seg6_update_csum(struct sk_buff *skb) 342{ 343 struct ipv6_sr_hdr *hdr; 344 struct in6_addr *addr; 345 __be32 from, to; 346 347 /* srh is at transport offset and seg_left is already decremented 348 * but daddr is not yet updated with next segment 349 */ 350 351 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 352 addr = hdr->segments + hdr->segments_left; 353 354 hdr->segments_left++; 355 from = *(__be32 *)hdr; 356 357 hdr->segments_left--; 358 to = *(__be32 *)hdr; 359 360 /* update skb csum with diff resulting from seg_left decrement */ 361 362 update_csum_diff4(skb, from, to); 363 364 /* compute csum diff between current and next segment and update */ 365 366 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 367 (__be32 *)addr); 368} 369 370static int ipv6_srh_rcv(struct sk_buff *skb) 371{ 372 struct inet6_skb_parm *opt = IP6CB(skb); 373 struct net *net = dev_net(skb->dev); 374 struct ipv6_sr_hdr *hdr; 375 struct inet6_dev *idev; 376 struct in6_addr *addr; 377 int accept_seg6; 378 379 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 380 381 idev = __in6_dev_get(skb->dev); 382 if (!idev) { 383 kfree_skb(skb); 384 return -1; 385 } 386 387 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled), 388 READ_ONCE(idev->cnf.seg6_enabled)); 389 390 if (!accept_seg6) { 391 kfree_skb(skb); 392 return -1; 393 } 394 395#ifdef CONFIG_IPV6_SEG6_HMAC 396 if (!seg6_hmac_validate_skb(skb)) { 397 kfree_skb(skb); 398 return -1; 399 } 400#endif 401 402looped_back: 403 if (hdr->segments_left == 0) { 404 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { 405 int offset = (hdr->hdrlen + 1) << 3; 406 407 skb_postpull_rcsum(skb, skb_network_header(skb), 408 skb_network_header_len(skb)); 409 skb_pull(skb, offset); 410 skb_postpull_rcsum(skb, skb_transport_header(skb), 411 offset); 412 413 skb_reset_network_header(skb); 414 skb_reset_transport_header(skb); 415 skb->encapsulation = 0; 416 if (hdr->nexthdr == NEXTHDR_IPV4) 417 skb->protocol = htons(ETH_P_IP); 418 __skb_tunnel_rx(skb, skb->dev, net); 419 420 netif_rx(skb); 421 return -1; 422 } 423 424 opt->srcrt = skb_network_header_len(skb); 425 opt->lastopt = opt->srcrt; 426 skb->transport_header += (hdr->hdrlen + 1) << 3; 427 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 428 429 return 1; 430 } 431 432 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 433 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 434 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 435 ((&hdr->segments_left) - 436 skb_network_header(skb))); 437 return -1; 438 } 439 440 if (skb_cloned(skb)) { 441 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 442 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 443 IPSTATS_MIB_OUTDISCARDS); 444 kfree_skb(skb); 445 return -1; 446 } 447 448 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 449 } 450 451 hdr->segments_left--; 452 addr = hdr->segments + hdr->segments_left; 453 454 skb_push(skb, sizeof(struct ipv6hdr)); 455 456 if (skb->ip_summed == CHECKSUM_COMPLETE) 457 seg6_update_csum(skb); 458 459 ipv6_hdr(skb)->daddr = *addr; 460 461 ip6_route_input(skb); 462 463 if (skb_dst(skb)->error) { 464 dst_input(skb); 465 return -1; 466 } 467 468 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 469 if (ipv6_hdr(skb)->hop_limit <= 1) { 470 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 471 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 472 ICMPV6_EXC_HOPLIMIT, 0); 473 kfree_skb(skb); 474 return -1; 475 } 476 ipv6_hdr(skb)->hop_limit--; 477 478 skb_pull(skb, sizeof(struct ipv6hdr)); 479 goto looped_back; 480 } 481 482 dst_input(skb); 483 484 return -1; 485} 486 487static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 488{ 489 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 490 struct inet6_skb_parm *opt = IP6CB(skb); 491 struct net *net = dev_net(skb->dev); 492 struct inet6_dev *idev; 493 struct ipv6hdr *oldhdr; 494 unsigned char *buf; 495 int accept_rpl_seg; 496 int i, err; 497 u64 n = 0; 498 u32 r; 499 500 idev = __in6_dev_get(skb->dev); 501 502 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled), 503 READ_ONCE(idev->cnf.rpl_seg_enabled)); 504 if (!accept_rpl_seg) { 505 kfree_skb(skb); 506 return -1; 507 } 508 509looped_back: 510 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 511 512 if (hdr->segments_left == 0) { 513 if (hdr->nexthdr == NEXTHDR_IPV6) { 514 int offset = (hdr->hdrlen + 1) << 3; 515 516 skb_postpull_rcsum(skb, skb_network_header(skb), 517 skb_network_header_len(skb)); 518 skb_pull(skb, offset); 519 skb_postpull_rcsum(skb, skb_transport_header(skb), 520 offset); 521 522 skb_reset_network_header(skb); 523 skb_reset_transport_header(skb); 524 skb->encapsulation = 0; 525 526 __skb_tunnel_rx(skb, skb->dev, net); 527 528 netif_rx(skb); 529 return -1; 530 } 531 532 opt->srcrt = skb_network_header_len(skb); 533 opt->lastopt = opt->srcrt; 534 skb->transport_header += (hdr->hdrlen + 1) << 3; 535 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 536 537 return 1; 538 } 539 540 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 541 r = do_div(n, (16 - hdr->cmpri)); 542 /* checks if calculation was without remainder and n fits into 543 * unsigned char which is segments_left field. Should not be 544 * higher than that. 545 */ 546 if (r || (n + 1) > 255) { 547 kfree_skb(skb); 548 return -1; 549 } 550 551 if (hdr->segments_left > n + 1) { 552 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 553 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 554 ((&hdr->segments_left) - 555 skb_network_header(skb))); 556 return -1; 557 } 558 559 hdr->segments_left--; 560 i = n - hdr->segments_left; 561 562 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 563 if (unlikely(!buf)) { 564 kfree_skb(skb); 565 return -1; 566 } 567 568 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 569 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 570 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 571 572 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) { 573 kfree_skb(skb); 574 kfree(buf); 575 return -1; 576 } 577 578 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 579 if (err) { 580 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 581 kfree_skb(skb); 582 kfree(buf); 583 return -1; 584 } 585 586 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); 587 588 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 589 590 oldhdr = ipv6_hdr(skb); 591 592 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 593 skb_postpull_rcsum(skb, oldhdr, 594 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 595 if (unlikely(!hdr->segments_left)) { 596 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, 597 GFP_ATOMIC)) { 598 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 599 kfree_skb(skb); 600 kfree(buf); 601 return -1; 602 } 603 604 oldhdr = ipv6_hdr(skb); 605 } 606 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 607 skb_reset_network_header(skb); 608 skb_mac_header_rebuild(skb); 609 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 610 611 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 612 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 613 614 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 615 skb_postpush_rcsum(skb, ipv6_hdr(skb), 616 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 617 618 kfree(buf); 619 620 ip6_route_input(skb); 621 622 if (skb_dst(skb)->error) { 623 dst_input(skb); 624 return -1; 625 } 626 627 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 628 if (ipv6_hdr(skb)->hop_limit <= 1) { 629 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 630 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 631 ICMPV6_EXC_HOPLIMIT, 0); 632 kfree_skb(skb); 633 return -1; 634 } 635 ipv6_hdr(skb)->hop_limit--; 636 637 skb_pull(skb, sizeof(struct ipv6hdr)); 638 goto looped_back; 639 } 640 641 dst_input(skb); 642 643 return -1; 644} 645 646/******************************** 647 Routing header. 648 ********************************/ 649 650/* called with rcu_read_lock() */ 651static int ipv6_rthdr_rcv(struct sk_buff *skb) 652{ 653 struct inet6_dev *idev = __in6_dev_get(skb->dev); 654 struct inet6_skb_parm *opt = IP6CB(skb); 655 struct in6_addr *addr = NULL; 656 int n, i; 657 struct ipv6_rt_hdr *hdr; 658 struct rt0_hdr *rthdr; 659 struct net *net = dev_net(skb->dev); 660 int accept_source_route; 661 662 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route); 663 664 if (idev) 665 accept_source_route = min(accept_source_route, 666 READ_ONCE(idev->cnf.accept_source_route)); 667 668 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 669 !pskb_may_pull(skb, (skb_transport_offset(skb) + 670 ((skb_transport_header(skb)[1] + 1) << 3)))) { 671 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 672 kfree_skb(skb); 673 return -1; 674 } 675 676 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 677 678 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 679 skb->pkt_type != PACKET_HOST) { 680 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 681 kfree_skb(skb); 682 return -1; 683 } 684 685 switch (hdr->type) { 686 case IPV6_SRCRT_TYPE_4: 687 /* segment routing */ 688 return ipv6_srh_rcv(skb); 689 case IPV6_SRCRT_TYPE_3: 690 /* rpl segment routing */ 691 return ipv6_rpl_srh_rcv(skb); 692 default: 693 break; 694 } 695 696looped_back: 697 if (hdr->segments_left == 0) { 698 switch (hdr->type) { 699#if IS_ENABLED(CONFIG_IPV6_MIP6) 700 case IPV6_SRCRT_TYPE_2: 701 /* Silently discard type 2 header unless it was 702 * processed by own 703 */ 704 if (!addr) { 705 __IP6_INC_STATS(net, idev, 706 IPSTATS_MIB_INADDRERRORS); 707 kfree_skb(skb); 708 return -1; 709 } 710 break; 711#endif 712 default: 713 break; 714 } 715 716 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 717 skb->transport_header += (hdr->hdrlen + 1) << 3; 718 opt->dst0 = opt->dst1; 719 opt->dst1 = 0; 720 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 721 return 1; 722 } 723 724 switch (hdr->type) { 725#if IS_ENABLED(CONFIG_IPV6_MIP6) 726 case IPV6_SRCRT_TYPE_2: 727 if (accept_source_route < 0) 728 goto unknown_rh; 729 /* Silently discard invalid RTH type 2 */ 730 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 731 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 732 kfree_skb(skb); 733 return -1; 734 } 735 break; 736#endif 737 default: 738 goto unknown_rh; 739 } 740 741 /* 742 * This is the routing header forwarding algorithm from 743 * RFC 2460, page 16. 744 */ 745 746 n = hdr->hdrlen >> 1; 747 748 if (hdr->segments_left > n) { 749 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 750 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 751 ((&hdr->segments_left) - 752 skb_network_header(skb))); 753 return -1; 754 } 755 756 /* We are about to mangle packet header. Be careful! 757 Do not damage packets queued somewhere. 758 */ 759 if (skb_cloned(skb)) { 760 /* the copy is a forwarded packet */ 761 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 762 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 763 IPSTATS_MIB_OUTDISCARDS); 764 kfree_skb(skb); 765 return -1; 766 } 767 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 768 } 769 770 if (skb->ip_summed == CHECKSUM_COMPLETE) 771 skb->ip_summed = CHECKSUM_NONE; 772 773 i = n - --hdr->segments_left; 774 775 rthdr = (struct rt0_hdr *) hdr; 776 addr = rthdr->addr; 777 addr += i - 1; 778 779 switch (hdr->type) { 780#if IS_ENABLED(CONFIG_IPV6_MIP6) 781 case IPV6_SRCRT_TYPE_2: 782 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 783 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 784 IPPROTO_ROUTING) < 0) { 785 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 786 kfree_skb(skb); 787 return -1; 788 } 789 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) { 790 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 791 kfree_skb(skb); 792 return -1; 793 } 794 break; 795#endif 796 default: 797 break; 798 } 799 800 if (ipv6_addr_is_multicast(addr)) { 801 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 802 kfree_skb(skb); 803 return -1; 804 } 805 806 swap(*addr, ipv6_hdr(skb)->daddr); 807 808 ip6_route_input(skb); 809 if (skb_dst(skb)->error) { 810 skb_push(skb, -skb_network_offset(skb)); 811 dst_input(skb); 812 return -1; 813 } 814 815 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 816 if (ipv6_hdr(skb)->hop_limit <= 1) { 817 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 818 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 819 0); 820 kfree_skb(skb); 821 return -1; 822 } 823 ipv6_hdr(skb)->hop_limit--; 824 goto looped_back; 825 } 826 827 skb_push(skb, -skb_network_offset(skb)); 828 dst_input(skb); 829 return -1; 830 831unknown_rh: 832 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 833 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 834 (&hdr->type) - skb_network_header(skb)); 835 return -1; 836} 837 838static const struct inet6_protocol rthdr_protocol = { 839 .handler = ipv6_rthdr_rcv, 840 .flags = INET6_PROTO_NOPOLICY, 841}; 842 843static const struct inet6_protocol destopt_protocol = { 844 .handler = ipv6_destopt_rcv, 845 .flags = INET6_PROTO_NOPOLICY, 846}; 847 848static const struct inet6_protocol nodata_protocol = { 849 .handler = dst_discard, 850 .flags = INET6_PROTO_NOPOLICY, 851}; 852 853int __init ipv6_exthdrs_init(void) 854{ 855 int ret; 856 857 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 858 if (ret) 859 goto out; 860 861 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 862 if (ret) 863 goto out_rthdr; 864 865 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 866 if (ret) 867 goto out_destopt; 868 869out: 870 return ret; 871out_destopt: 872 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 873out_rthdr: 874 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 875 goto out; 876}; 877 878void ipv6_exthdrs_exit(void) 879{ 880 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 881 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 882 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 883} 884 885/********************************** 886 Hop-by-hop options. 887 **********************************/ 888 889/* Router Alert as of RFC 2711 */ 890 891static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 892{ 893 const unsigned char *nh = skb_network_header(skb); 894 895 if (nh[optoff + 1] == 2) { 896 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 897 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 898 return true; 899 } 900 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 901 nh[optoff + 1]); 902 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 903 return false; 904} 905 906/* IOAM */ 907 908static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 909{ 910 struct ioam6_trace_hdr *trace; 911 struct ioam6_namespace *ns; 912 struct ioam6_hdr *hdr; 913 914 /* Bad alignment (must be 4n-aligned) */ 915 if (optoff & 3) 916 goto drop; 917 918 /* Ignore if IOAM is not enabled on ingress */ 919 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled)) 920 goto ignore; 921 922 /* Truncated Option header */ 923 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 924 if (hdr->opt_len < 2) 925 goto drop; 926 927 switch (hdr->type) { 928 case IOAM6_TYPE_PREALLOC: 929 /* Truncated Pre-allocated Trace header */ 930 if (hdr->opt_len < 2 + sizeof(*trace)) 931 goto drop; 932 933 /* Malformed Pre-allocated Trace header */ 934 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 935 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 936 goto drop; 937 938 /* Inconsistent Pre-allocated Trace header */ 939 if (trace->nodelen != 940 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32))) 941 goto drop; 942 943 /* Ignore if the IOAM namespace is unknown */ 944 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id); 945 if (!ns) 946 goto ignore; 947 948 if (!skb_valid_dst(skb)) 949 ip6_route_input(skb); 950 951 /* About to mangle packet header */ 952 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) 953 goto drop; 954 955 /* Trace pointer may have changed */ 956 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) 957 + optoff + sizeof(*hdr)); 958 959 ioam6_fill_trace_data(skb, ns, trace, true); 960 961 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), 962 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); 963 break; 964 default: 965 break; 966 } 967 968ignore: 969 return true; 970 971drop: 972 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 973 return false; 974} 975 976/* Jumbo payload */ 977 978static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 979{ 980 const unsigned char *nh = skb_network_header(skb); 981 SKB_DR(reason); 982 u32 pkt_len; 983 984 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 985 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 986 nh[optoff+1]); 987 SKB_DR_SET(reason, IP_INHDR); 988 goto drop; 989 } 990 991 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 992 if (pkt_len <= IPV6_MAXPLEN) { 993 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 994 SKB_DROP_REASON_IP_INHDR); 995 return false; 996 } 997 if (ipv6_hdr(skb)->payload_len) { 998 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 999 SKB_DROP_REASON_IP_INHDR); 1000 return false; 1001 } 1002 1003 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 1004 SKB_DR_SET(reason, PKT_TOO_SMALL); 1005 goto drop; 1006 } 1007 1008 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 1009 goto drop; 1010 1011 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 1012 return true; 1013 1014drop: 1015 kfree_skb_reason(skb, reason); 1016 return false; 1017} 1018 1019/* CALIPSO RFC 5570 */ 1020 1021static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1022{ 1023 const unsigned char *nh = skb_network_header(skb); 1024 1025 if (nh[optoff + 1] < 8) 1026 goto drop; 1027 1028 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1029 goto drop; 1030 1031 if (!calipso_validate(skb, nh + optoff)) 1032 goto drop; 1033 1034 return true; 1035 1036drop: 1037 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1038 return false; 1039} 1040 1041int ipv6_parse_hopopts(struct sk_buff *skb) 1042{ 1043 struct inet6_skb_parm *opt = IP6CB(skb); 1044 struct net *net = dev_net(skb->dev); 1045 int extlen; 1046 1047 /* 1048 * skb_network_header(skb) is equal to skb->data, and 1049 * skb_network_header_len(skb) is always equal to 1050 * sizeof(struct ipv6hdr) by definition of 1051 * hop-by-hop options. 1052 */ 1053 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1054 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1055 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1056fail_and_free: 1057 kfree_skb(skb); 1058 return -1; 1059 } 1060 1061 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1062 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len)) 1063 goto fail_and_free; 1064 1065 opt->flags |= IP6SKB_HOPBYHOP; 1066 if (ip6_parse_tlv(true, skb, 1067 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) { 1068 skb->transport_header += extlen; 1069 opt = IP6CB(skb); 1070 opt->nhoff = sizeof(struct ipv6hdr); 1071 return 1; 1072 } 1073 return -1; 1074} 1075 1076/* 1077 * Creating outbound headers. 1078 * 1079 * "build" functions work when skb is filled from head to tail (datagram) 1080 * "push" functions work when headers are added from tail to head (tcp) 1081 * 1082 * In both cases we assume, that caller reserved enough room 1083 * for headers. 1084 */ 1085 1086static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1087 struct ipv6_rt_hdr *opt, 1088 struct in6_addr **addr_p, struct in6_addr *saddr) 1089{ 1090 struct rt0_hdr *phdr, *ihdr; 1091 int hops; 1092 1093 ihdr = (struct rt0_hdr *) opt; 1094 1095 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1096 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1097 1098 hops = ihdr->rt_hdr.hdrlen >> 1; 1099 1100 if (hops > 1) 1101 memcpy(phdr->addr, ihdr->addr + 1, 1102 (hops - 1) * sizeof(struct in6_addr)); 1103 1104 phdr->addr[hops - 1] = **addr_p; 1105 *addr_p = ihdr->addr; 1106 1107 phdr->rt_hdr.nexthdr = *proto; 1108 *proto = NEXTHDR_ROUTING; 1109} 1110 1111static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1112 struct ipv6_rt_hdr *opt, 1113 struct in6_addr **addr_p, struct in6_addr *saddr) 1114{ 1115 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1116 int plen, hops; 1117 1118 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1119 plen = (sr_ihdr->hdrlen + 1) << 3; 1120 1121 sr_phdr = skb_push(skb, plen); 1122 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1123 1124 hops = sr_ihdr->first_segment + 1; 1125 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1126 (hops - 1) * sizeof(struct in6_addr)); 1127 1128 sr_phdr->segments[0] = **addr_p; 1129 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1130 1131 if (sr_ihdr->hdrlen > hops * 2) { 1132 int tlvs_offset, tlvs_length; 1133 1134 tlvs_offset = (1 + hops * 2) << 3; 1135 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1136 memcpy((char *)sr_phdr + tlvs_offset, 1137 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1138 } 1139 1140#ifdef CONFIG_IPV6_SEG6_HMAC 1141 if (sr_has_hmac(sr_phdr)) { 1142 struct net *net = NULL; 1143 1144 if (skb->dev) 1145 net = dev_net(skb->dev); 1146 else if (skb->sk) 1147 net = sock_net(skb->sk); 1148 1149 WARN_ON(!net); 1150 1151 if (net) 1152 seg6_push_hmac(net, saddr, sr_phdr); 1153 } 1154#endif 1155 1156 sr_phdr->nexthdr = *proto; 1157 *proto = NEXTHDR_ROUTING; 1158} 1159 1160static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1161 struct ipv6_rt_hdr *opt, 1162 struct in6_addr **addr_p, struct in6_addr *saddr) 1163{ 1164 switch (opt->type) { 1165 case IPV6_SRCRT_TYPE_0: 1166 case IPV6_SRCRT_STRICT: 1167 case IPV6_SRCRT_TYPE_2: 1168 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1169 break; 1170 case IPV6_SRCRT_TYPE_4: 1171 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1172 break; 1173 default: 1174 break; 1175 } 1176} 1177 1178static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1179{ 1180 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1181 1182 memcpy(h, opt, ipv6_optlen(opt)); 1183 h->nexthdr = *proto; 1184 *proto = type; 1185} 1186 1187void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1188 u8 *proto, 1189 struct in6_addr **daddr, struct in6_addr *saddr) 1190{ 1191 if (opt->srcrt) { 1192 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1193 /* 1194 * IPV6_RTHDRDSTOPTS is ignored 1195 * unless IPV6_RTHDR is set (RFC3542). 1196 */ 1197 if (opt->dst0opt) 1198 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1199 } 1200 if (opt->hopopt) 1201 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1202} 1203 1204void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1205{ 1206 if (opt->dst1opt) 1207 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1208} 1209EXPORT_SYMBOL(ipv6_push_frag_opts); 1210 1211struct ipv6_txoptions * 1212ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1213{ 1214 struct ipv6_txoptions *opt2; 1215 1216 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC); 1217 if (opt2) { 1218 long dif = (char *)opt2 - (char *)opt; 1219 if (opt2->hopopt) 1220 *((char **)&opt2->hopopt) += dif; 1221 if (opt2->dst0opt) 1222 *((char **)&opt2->dst0opt) += dif; 1223 if (opt2->dst1opt) 1224 *((char **)&opt2->dst1opt) += dif; 1225 if (opt2->srcrt) 1226 *((char **)&opt2->srcrt) += dif; 1227 refcount_set(&opt2->refcnt, 1); 1228 } 1229 return opt2; 1230} 1231EXPORT_SYMBOL_GPL(ipv6_dup_options); 1232 1233static void ipv6_renew_option(int renewtype, 1234 struct ipv6_opt_hdr **dest, 1235 struct ipv6_opt_hdr *old, 1236 struct ipv6_opt_hdr *new, 1237 int newtype, char **p) 1238{ 1239 struct ipv6_opt_hdr *src; 1240 1241 src = (renewtype == newtype ? new : old); 1242 if (!src) 1243 return; 1244 1245 memcpy(*p, src, ipv6_optlen(src)); 1246 *dest = (struct ipv6_opt_hdr *)*p; 1247 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1248} 1249 1250/** 1251 * ipv6_renew_options - replace a specific ext hdr with a new one. 1252 * 1253 * @sk: sock from which to allocate memory 1254 * @opt: original options 1255 * @newtype: option type to replace in @opt 1256 * @newopt: new option of type @newtype to replace (user-mem) 1257 * 1258 * Returns a new set of options which is a copy of @opt with the 1259 * option type @newtype replaced with @newopt. 1260 * 1261 * @opt may be NULL, in which case a new set of options is returned 1262 * containing just @newopt. 1263 * 1264 * @newopt may be NULL, in which case the specified option type is 1265 * not copied into the new set of options. 1266 * 1267 * The new set of options is allocated from the socket option memory 1268 * buffer of @sk. 1269 */ 1270struct ipv6_txoptions * 1271ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1272 int newtype, struct ipv6_opt_hdr *newopt) 1273{ 1274 int tot_len = 0; 1275 char *p; 1276 struct ipv6_txoptions *opt2; 1277 1278 if (opt) { 1279 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1280 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1281 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1282 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1283 if (newtype != IPV6_RTHDR && opt->srcrt) 1284 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1285 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1286 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1287 } 1288 1289 if (newopt) 1290 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1291 1292 if (!tot_len) 1293 return NULL; 1294 1295 tot_len += sizeof(*opt2); 1296 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1297 if (!opt2) 1298 return ERR_PTR(-ENOBUFS); 1299 1300 memset(opt2, 0, tot_len); 1301 refcount_set(&opt2->refcnt, 1); 1302 opt2->tot_len = tot_len; 1303 p = (char *)(opt2 + 1); 1304 1305 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1306 (opt ? opt->hopopt : NULL), 1307 newopt, newtype, &p); 1308 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1309 (opt ? opt->dst0opt : NULL), 1310 newopt, newtype, &p); 1311 ipv6_renew_option(IPV6_RTHDR, 1312 (struct ipv6_opt_hdr **)&opt2->srcrt, 1313 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1314 newopt, newtype, &p); 1315 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1316 (opt ? opt->dst1opt : NULL), 1317 newopt, newtype, &p); 1318 1319 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1320 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1321 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1322 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1323 1324 return opt2; 1325} 1326 1327struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1328 struct ipv6_txoptions *opt) 1329{ 1330 /* 1331 * ignore the dest before srcrt unless srcrt is being included. 1332 * --yoshfuji 1333 */ 1334 if (opt->dst0opt && !opt->srcrt) { 1335 if (opt_space != opt) { 1336 memcpy(opt_space, opt, sizeof(*opt_space)); 1337 opt = opt_space; 1338 } 1339 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1340 opt->dst0opt = NULL; 1341 } 1342 1343 return opt; 1344} 1345EXPORT_SYMBOL_GPL(__ipv6_fixup_options); 1346 1347/** 1348 * fl6_update_dst - update flowi destination address with info given 1349 * by srcrt option, if any. 1350 * 1351 * @fl6: flowi6 for which daddr is to be updated 1352 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1353 * @orig: copy of original daddr address if modified 1354 * 1355 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1356 * and initial value of fl6->daddr set in orig 1357 */ 1358struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1359 const struct ipv6_txoptions *opt, 1360 struct in6_addr *orig) 1361{ 1362 if (!opt || !opt->srcrt) 1363 return NULL; 1364 1365 *orig = fl6->daddr; 1366 1367 switch (opt->srcrt->type) { 1368 case IPV6_SRCRT_TYPE_0: 1369 case IPV6_SRCRT_STRICT: 1370 case IPV6_SRCRT_TYPE_2: 1371 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1372 break; 1373 case IPV6_SRCRT_TYPE_4: 1374 { 1375 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1376 1377 fl6->daddr = srh->segments[srh->segments_left]; 1378 break; 1379 } 1380 default: 1381 return NULL; 1382 } 1383 1384 return orig; 1385} 1386EXPORT_SYMBOL_GPL(fl6_update_dst);
~/
Read-only file preview.