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; 180 181 nh = skb_network_header(skb); 182 break; 183 case IPV6_TLV_JUMBO: 184 if (!ipv6_hop_jumbo(skb, off)) 185 return false; 186 break; 187 case IPV6_TLV_CALIPSO: 188 if (!ipv6_hop_calipso(skb, off)) 189 return false; 190 break; 191 default: 192 if (!ip6_tlvopt_unknown(skb, off, 193 disallow_unknowns)) 194 return false; 195 break; 196 } 197 } else { 198 switch (nh[off]) { 199 #if IS_ENABLED(CONFIG_IPV6_MIP6) 200 case IPV6_TLV_HAO: 201 if (!ipv6_dest_hao(skb, off)) 202 return false; 203 break; 204 #endif 205 default: 206 if (!ip6_tlvopt_unknown(skb, off, 207 disallow_unknowns)) 208 return false; 209 break; 210 } 211 } 212 padlen = 0; 213 } 214 off += optlen; 215 len -= optlen; 216 } 217 218 if (len == 0) 219 return true; 220 bad: 221 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 222 return false; 223 } 224 225 /***************************** 226 Destination options header. 227 *****************************/ 228 229 #if IS_ENABLED(CONFIG_IPV6_MIP6) 230 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 231 { 232 struct ipv6_destopt_hao *hao; 233 struct inet6_skb_parm *opt = IP6CB(skb); 234 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 235 SKB_DR(reason); 236 int ret; 237 238 if (opt->dsthao) { 239 net_dbg_ratelimited("hao duplicated\n"); 240 goto discard; 241 } 242 opt->dsthao = opt->dst1; 243 opt->dst1 = 0; 244 245 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 246 247 if (hao->length != 16) { 248 net_dbg_ratelimited("hao invalid option length = %d\n", 249 hao->length); 250 SKB_DR_SET(reason, IP_INHDR); 251 goto discard; 252 } 253 254 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 255 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 256 &hao->addr); 257 SKB_DR_SET(reason, INVALID_PROTO); 258 goto discard; 259 } 260 261 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 262 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 263 if (unlikely(ret < 0)) { 264 SKB_DR_SET(reason, XFRM_POLICY); 265 goto discard; 266 } 267 268 if (skb_cloned(skb)) { 269 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 270 goto discard; 271 272 /* update all variable using below by copied skbuff */ 273 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 274 optoff); 275 ipv6h = ipv6_hdr(skb); 276 } 277 278 if (skb->ip_summed == CHECKSUM_COMPLETE) 279 skb->ip_summed = CHECKSUM_NONE; 280 281 swap(ipv6h->saddr, hao->addr); 282 283 if (skb->tstamp == 0) 284 __net_timestamp(skb); 285 286 return true; 287 288 discard: 289 kfree_skb_reason(skb, reason); 290 return false; 291 } 292 #endif 293 294 static int ipv6_destopt_rcv(struct sk_buff *skb) 295 { 296 struct inet6_dev *idev = __in6_dev_get(skb->dev); 297 struct inet6_skb_parm *opt = IP6CB(skb); 298 #if IS_ENABLED(CONFIG_IPV6_MIP6) 299 __u16 dstbuf; 300 #endif 301 struct dst_entry *dst = skb_dst(skb); 302 struct net *net = dev_net(skb->dev); 303 int extlen; 304 305 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 306 !pskb_may_pull(skb, (skb_transport_offset(skb) + 307 ((skb_transport_header(skb)[1] + 1) << 3)))) { 308 __IP6_INC_STATS(dev_net(dst->dev), idev, 309 IPSTATS_MIB_INHDRERRORS); 310 fail_and_free: 311 kfree_skb(skb); 312 return -1; 313 } 314 315 extlen = (skb_transport_header(skb)[1] + 1) << 3; 316 if (extlen > net->ipv6.sysctl.max_dst_opts_len) 317 goto fail_and_free; 318 319 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 320 #if IS_ENABLED(CONFIG_IPV6_MIP6) 321 dstbuf = opt->dst1; 322 #endif 323 324 if (ip6_parse_tlv(false, skb, net->ipv6.sysctl.max_dst_opts_cnt)) { 325 skb->transport_header += extlen; 326 opt = IP6CB(skb); 327 #if IS_ENABLED(CONFIG_IPV6_MIP6) 328 opt->nhoff = dstbuf; 329 #else 330 opt->nhoff = opt->dst1; 331 #endif 332 return 1; 333 } 334 335 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 336 return -1; 337 } 338 339 static void seg6_update_csum(struct sk_buff *skb) 340 { 341 struct ipv6_sr_hdr *hdr; 342 struct in6_addr *addr; 343 __be32 from, to; 344 345 /* srh is at transport offset and seg_left is already decremented 346 * but daddr is not yet updated with next segment 347 */ 348 349 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 350 addr = hdr->segments + hdr->segments_left; 351 352 hdr->segments_left++; 353 from = *(__be32 *)hdr; 354 355 hdr->segments_left--; 356 to = *(__be32 *)hdr; 357 358 /* update skb csum with diff resulting from seg_left decrement */ 359 360 update_csum_diff4(skb, from, to); 361 362 /* compute csum diff between current and next segment and update */ 363 364 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 365 (__be32 *)addr); 366 } 367 368 static int ipv6_srh_rcv(struct sk_buff *skb) 369 { 370 struct inet6_skb_parm *opt = IP6CB(skb); 371 struct net *net = dev_net(skb->dev); 372 struct ipv6_sr_hdr *hdr; 373 struct inet6_dev *idev; 374 struct in6_addr *addr; 375 int accept_seg6; 376 377 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 378 379 idev = __in6_dev_get(skb->dev); 380 381 accept_seg6 = net->ipv6.devconf_all->seg6_enabled; 382 if (accept_seg6 > idev->cnf.seg6_enabled) 383 accept_seg6 = idev->cnf.seg6_enabled; 384 385 if (!accept_seg6) { 386 kfree_skb(skb); 387 return -1; 388 } 389 390 #ifdef CONFIG_IPV6_SEG6_HMAC 391 if (!seg6_hmac_validate_skb(skb)) { 392 kfree_skb(skb); 393 return -1; 394 } 395 #endif 396 397 looped_back: 398 if (hdr->segments_left == 0) { 399 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { 400 int offset = (hdr->hdrlen + 1) << 3; 401 402 skb_postpull_rcsum(skb, skb_network_header(skb), 403 skb_network_header_len(skb)); 404 skb_pull(skb, offset); 405 skb_postpull_rcsum(skb, skb_transport_header(skb), 406 offset); 407 408 skb_reset_network_header(skb); 409 skb_reset_transport_header(skb); 410 skb->encapsulation = 0; 411 if (hdr->nexthdr == NEXTHDR_IPV4) 412 skb->protocol = htons(ETH_P_IP); 413 __skb_tunnel_rx(skb, skb->dev, net); 414 415 netif_rx(skb); 416 return -1; 417 } 418 419 opt->srcrt = skb_network_header_len(skb); 420 opt->lastopt = opt->srcrt; 421 skb->transport_header += (hdr->hdrlen + 1) << 3; 422 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 423 424 return 1; 425 } 426 427 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 428 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 429 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 430 ((&hdr->segments_left) - 431 skb_network_header(skb))); 432 return -1; 433 } 434 435 if (skb_cloned(skb)) { 436 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 437 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 438 IPSTATS_MIB_OUTDISCARDS); 439 kfree_skb(skb); 440 return -1; 441 } 442 443 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 444 } 445 446 hdr->segments_left--; 447 addr = hdr->segments + hdr->segments_left; 448 449 skb_push(skb, sizeof(struct ipv6hdr)); 450 451 if (skb->ip_summed == CHECKSUM_COMPLETE) 452 seg6_update_csum(skb); 453 454 ipv6_hdr(skb)->daddr = *addr; 455 456 ip6_route_input(skb); 457 458 if (skb_dst(skb)->error) { 459 dst_input(skb); 460 return -1; 461 } 462 463 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 464 if (ipv6_hdr(skb)->hop_limit <= 1) { 465 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 466 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 467 ICMPV6_EXC_HOPLIMIT, 0); 468 kfree_skb(skb); 469 return -1; 470 } 471 ipv6_hdr(skb)->hop_limit--; 472 473 skb_pull(skb, sizeof(struct ipv6hdr)); 474 goto looped_back; 475 } 476 477 dst_input(skb); 478 479 return -1; 480 } 481 482 static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 483 { 484 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 485 struct inet6_skb_parm *opt = IP6CB(skb); 486 struct net *net = dev_net(skb->dev); 487 struct inet6_dev *idev; 488 struct ipv6hdr *oldhdr; 489 unsigned char *buf; 490 int accept_rpl_seg; 491 int i, err; 492 u64 n = 0; 493 u32 r; 494 495 idev = __in6_dev_get(skb->dev); 496 497 accept_rpl_seg = net->ipv6.devconf_all->rpl_seg_enabled; 498 if (accept_rpl_seg > idev->cnf.rpl_seg_enabled) 499 accept_rpl_seg = idev->cnf.rpl_seg_enabled; 500 501 if (!accept_rpl_seg) { 502 kfree_skb(skb); 503 return -1; 504 } 505 506 looped_back: 507 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 508 509 if (hdr->segments_left == 0) { 510 if (hdr->nexthdr == NEXTHDR_IPV6) { 511 int offset = (hdr->hdrlen + 1) << 3; 512 513 skb_postpull_rcsum(skb, skb_network_header(skb), 514 skb_network_header_len(skb)); 515 skb_pull(skb, offset); 516 skb_postpull_rcsum(skb, skb_transport_header(skb), 517 offset); 518 519 skb_reset_network_header(skb); 520 skb_reset_transport_header(skb); 521 skb->encapsulation = 0; 522 523 __skb_tunnel_rx(skb, skb->dev, net); 524 525 netif_rx(skb); 526 return -1; 527 } 528 529 opt->srcrt = skb_network_header_len(skb); 530 opt->lastopt = opt->srcrt; 531 skb->transport_header += (hdr->hdrlen + 1) << 3; 532 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 533 534 return 1; 535 } 536 537 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 538 r = do_div(n, (16 - hdr->cmpri)); 539 /* checks if calculation was without remainder and n fits into 540 * unsigned char which is segments_left field. Should not be 541 * higher than that. 542 */ 543 if (r || (n + 1) > 255) { 544 kfree_skb(skb); 545 return -1; 546 } 547 548 if (hdr->segments_left > n + 1) { 549 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 550 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 551 ((&hdr->segments_left) - 552 skb_network_header(skb))); 553 return -1; 554 } 555 556 hdr->segments_left--; 557 i = n - hdr->segments_left; 558 559 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 560 if (unlikely(!buf)) { 561 kfree_skb(skb); 562 return -1; 563 } 564 565 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 566 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 567 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 568 569 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) { 570 kfree_skb(skb); 571 kfree(buf); 572 return -1; 573 } 574 575 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 576 if (err) { 577 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 578 kfree_skb(skb); 579 kfree(buf); 580 return -1; 581 } 582 583 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); 584 585 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 586 587 oldhdr = ipv6_hdr(skb); 588 589 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 590 skb_postpull_rcsum(skb, oldhdr, 591 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 592 if (unlikely(!hdr->segments_left)) { 593 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, 594 GFP_ATOMIC)) { 595 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 596 kfree_skb(skb); 597 kfree(buf); 598 return -1; 599 } 600 601 oldhdr = ipv6_hdr(skb); 602 } 603 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 604 skb_reset_network_header(skb); 605 skb_mac_header_rebuild(skb); 606 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 607 608 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 609 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 610 611 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 612 skb_postpush_rcsum(skb, ipv6_hdr(skb), 613 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 614 615 kfree(buf); 616 617 ip6_route_input(skb); 618 619 if (skb_dst(skb)->error) { 620 dst_input(skb); 621 return -1; 622 } 623 624 if (skb_dst(skb)->dev->flags & IFF_LOOPBACK) { 625 if (ipv6_hdr(skb)->hop_limit <= 1) { 626 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 627 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 628 ICMPV6_EXC_HOPLIMIT, 0); 629 kfree_skb(skb); 630 return -1; 631 } 632 ipv6_hdr(skb)->hop_limit--; 633 634 skb_pull(skb, sizeof(struct ipv6hdr)); 635 goto looped_back; 636 } 637 638 dst_input(skb); 639 640 return -1; 641 } 642 643 /******************************** 644 Routing header. 645 ********************************/ 646 647 /* called with rcu_read_lock() */ 648 static int ipv6_rthdr_rcv(struct sk_buff *skb) 649 { 650 struct inet6_dev *idev = __in6_dev_get(skb->dev); 651 struct inet6_skb_parm *opt = IP6CB(skb); 652 struct in6_addr *addr = NULL; 653 int n, i; 654 struct ipv6_rt_hdr *hdr; 655 struct rt0_hdr *rthdr; 656 struct net *net = dev_net(skb->dev); 657 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 658 659 if (idev && accept_source_route > idev->cnf.accept_source_route) 660 accept_source_route = idev->cnf.accept_source_route; 661 662 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 663 !pskb_may_pull(skb, (skb_transport_offset(skb) + 664 ((skb_transport_header(skb)[1] + 1) << 3)))) { 665 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 666 kfree_skb(skb); 667 return -1; 668 } 669 670 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 671 672 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 673 skb->pkt_type != PACKET_HOST) { 674 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 675 kfree_skb(skb); 676 return -1; 677 } 678 679 switch (hdr->type) { 680 case IPV6_SRCRT_TYPE_4: 681 /* segment routing */ 682 return ipv6_srh_rcv(skb); 683 case IPV6_SRCRT_TYPE_3: 684 /* rpl segment routing */ 685 return ipv6_rpl_srh_rcv(skb); 686 default: 687 break; 688 } 689 690 looped_back: 691 if (hdr->segments_left == 0) { 692 switch (hdr->type) { 693 #if IS_ENABLED(CONFIG_IPV6_MIP6) 694 case IPV6_SRCRT_TYPE_2: 695 /* Silently discard type 2 header unless it was 696 * processed by own 697 */ 698 if (!addr) { 699 __IP6_INC_STATS(net, idev, 700 IPSTATS_MIB_INADDRERRORS); 701 kfree_skb(skb); 702 return -1; 703 } 704 break; 705 #endif 706 default: 707 break; 708 } 709 710 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 711 skb->transport_header += (hdr->hdrlen + 1) << 3; 712 opt->dst0 = opt->dst1; 713 opt->dst1 = 0; 714 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 715 return 1; 716 } 717 718 switch (hdr->type) { 719 #if IS_ENABLED(CONFIG_IPV6_MIP6) 720 case IPV6_SRCRT_TYPE_2: 721 if (accept_source_route < 0) 722 goto unknown_rh; 723 /* Silently discard invalid RTH type 2 */ 724 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 725 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 726 kfree_skb(skb); 727 return -1; 728 } 729 break; 730 #endif 731 default: 732 goto unknown_rh; 733 } 734 735 /* 736 * This is the routing header forwarding algorithm from 737 * RFC 2460, page 16. 738 */ 739 740 n = hdr->hdrlen >> 1; 741 742 if (hdr->segments_left > n) { 743 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 744 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 745 ((&hdr->segments_left) - 746 skb_network_header(skb))); 747 return -1; 748 } 749 750 /* We are about to mangle packet header. Be careful! 751 Do not damage packets queued somewhere. 752 */ 753 if (skb_cloned(skb)) { 754 /* the copy is a forwarded packet */ 755 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 756 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 757 IPSTATS_MIB_OUTDISCARDS); 758 kfree_skb(skb); 759 return -1; 760 } 761 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 762 } 763 764 if (skb->ip_summed == CHECKSUM_COMPLETE) 765 skb->ip_summed = CHECKSUM_NONE; 766 767 i = n - --hdr->segments_left; 768 769 rthdr = (struct rt0_hdr *) hdr; 770 addr = rthdr->addr; 771 addr += i - 1; 772 773 switch (hdr->type) { 774 #if IS_ENABLED(CONFIG_IPV6_MIP6) 775 case IPV6_SRCRT_TYPE_2: 776 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 777 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 778 IPPROTO_ROUTING) < 0) { 779 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 780 kfree_skb(skb); 781 return -1; 782 } 783 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 784 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 785 kfree_skb(skb); 786 return -1; 787 } 788 break; 789 #endif 790 default: 791 break; 792 } 793 794 if (ipv6_addr_is_multicast(addr)) { 795 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 796 kfree_skb(skb); 797 return -1; 798 } 799 800 swap(*addr, ipv6_hdr(skb)->daddr); 801 802 ip6_route_input(skb); 803 if (skb_dst(skb)->error) { 804 skb_push(skb, skb->data - skb_network_header(skb)); 805 dst_input(skb); 806 return -1; 807 } 808 809 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 810 if (ipv6_hdr(skb)->hop_limit <= 1) { 811 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 812 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 813 0); 814 kfree_skb(skb); 815 return -1; 816 } 817 ipv6_hdr(skb)->hop_limit--; 818 goto looped_back; 819 } 820 821 skb_push(skb, skb->data - skb_network_header(skb)); 822 dst_input(skb); 823 return -1; 824 825 unknown_rh: 826 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 827 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 828 (&hdr->type) - skb_network_header(skb)); 829 return -1; 830 } 831 832 static const struct inet6_protocol rthdr_protocol = { 833 .handler = ipv6_rthdr_rcv, 834 .flags = INET6_PROTO_NOPOLICY, 835 }; 836 837 static const struct inet6_protocol destopt_protocol = { 838 .handler = ipv6_destopt_rcv, 839 .flags = INET6_PROTO_NOPOLICY, 840 }; 841 842 static const struct inet6_protocol nodata_protocol = { 843 .handler = dst_discard, 844 .flags = INET6_PROTO_NOPOLICY, 845 }; 846 847 int __init ipv6_exthdrs_init(void) 848 { 849 int ret; 850 851 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 852 if (ret) 853 goto out; 854 855 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 856 if (ret) 857 goto out_rthdr; 858 859 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 860 if (ret) 861 goto out_destopt; 862 863 out: 864 return ret; 865 out_destopt: 866 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 867 out_rthdr: 868 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 869 goto out; 870 }; 871 872 void ipv6_exthdrs_exit(void) 873 { 874 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 875 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 876 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 877 } 878 879 /********************************** 880 Hop-by-hop options. 881 **********************************/ 882 883 /* 884 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 885 */ 886 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 887 { 888 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 889 } 890 891 /* Router Alert as of RFC 2711 */ 892 893 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 894 { 895 const unsigned char *nh = skb_network_header(skb); 896 897 if (nh[optoff + 1] == 2) { 898 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 899 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 900 return true; 901 } 902 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 903 nh[optoff + 1]); 904 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 905 return false; 906 } 907 908 /* IOAM */ 909 910 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 911 { 912 struct ioam6_trace_hdr *trace; 913 struct ioam6_namespace *ns; 914 struct ioam6_hdr *hdr; 915 916 /* Bad alignment (must be 4n-aligned) */ 917 if (optoff & 3) 918 goto drop; 919 920 /* Ignore if IOAM is not enabled on ingress */ 921 if (!__in6_dev_get(skb->dev)->cnf.ioam6_enabled) 922 goto ignore; 923 924 /* Truncated Option header */ 925 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 926 if (hdr->opt_len < 2) 927 goto drop; 928 929 switch (hdr->type) { 930 case IOAM6_TYPE_PREALLOC: 931 /* Truncated Pre-allocated Trace header */ 932 if (hdr->opt_len < 2 + sizeof(*trace)) 933 goto drop; 934 935 /* Malformed Pre-allocated Trace header */ 936 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 937 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 938 goto drop; 939 940 /* Ignore if the IOAM namespace is unknown */ 941 ns = ioam6_namespace(ipv6_skb_net(skb), trace->namespace_id); 942 if (!ns) 943 goto ignore; 944 945 if (!skb_valid_dst(skb)) 946 ip6_route_input(skb); 947 948 /* About to mangle packet header */ 949 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) 950 goto drop; 951 952 /* Trace pointer may have changed */ 953 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) 954 + optoff + sizeof(*hdr)); 955 956 ioam6_fill_trace_data(skb, ns, trace, true); 957 break; 958 default: 959 break; 960 } 961 962 ignore: 963 return true; 964 965 drop: 966 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 967 return false; 968 } 969 970 /* Jumbo payload */ 971 972 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 973 { 974 const unsigned char *nh = skb_network_header(skb); 975 SKB_DR(reason); 976 u32 pkt_len; 977 978 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 979 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 980 nh[optoff+1]); 981 SKB_DR_SET(reason, IP_INHDR); 982 goto drop; 983 } 984 985 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 986 if (pkt_len <= IPV6_MAXPLEN) { 987 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 988 SKB_DROP_REASON_IP_INHDR); 989 return false; 990 } 991 if (ipv6_hdr(skb)->payload_len) { 992 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 993 SKB_DROP_REASON_IP_INHDR); 994 return false; 995 } 996 997 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 998 SKB_DR_SET(reason, PKT_TOO_SMALL); 999 goto drop; 1000 } 1001 1002 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 1003 goto drop; 1004 1005 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 1006 return true; 1007 1008 drop: 1009 kfree_skb_reason(skb, reason); 1010 return false; 1011 } 1012 1013 /* CALIPSO RFC 5570 */ 1014 1015 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1016 { 1017 const unsigned char *nh = skb_network_header(skb); 1018 1019 if (nh[optoff + 1] < 8) 1020 goto drop; 1021 1022 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1023 goto drop; 1024 1025 if (!calipso_validate(skb, nh + optoff)) 1026 goto drop; 1027 1028 return true; 1029 1030 drop: 1031 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1032 return false; 1033 } 1034 1035 int ipv6_parse_hopopts(struct sk_buff *skb) 1036 { 1037 struct inet6_skb_parm *opt = IP6CB(skb); 1038 struct net *net = dev_net(skb->dev); 1039 int extlen; 1040 1041 /* 1042 * skb_network_header(skb) is equal to skb->data, and 1043 * skb_network_header_len(skb) is always equal to 1044 * sizeof(struct ipv6hdr) by definition of 1045 * hop-by-hop options. 1046 */ 1047 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1048 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1049 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1050 fail_and_free: 1051 kfree_skb(skb); 1052 return -1; 1053 } 1054 1055 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1056 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 1057 goto fail_and_free; 1058 1059 opt->flags |= IP6SKB_HOPBYHOP; 1060 if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) { 1061 skb->transport_header += extlen; 1062 opt = IP6CB(skb); 1063 opt->nhoff = sizeof(struct ipv6hdr); 1064 return 1; 1065 } 1066 return -1; 1067 } 1068 1069 /* 1070 * Creating outbound headers. 1071 * 1072 * "build" functions work when skb is filled from head to tail (datagram) 1073 * "push" functions work when headers are added from tail to head (tcp) 1074 * 1075 * In both cases we assume, that caller reserved enough room 1076 * for headers. 1077 */ 1078 1079 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1080 struct ipv6_rt_hdr *opt, 1081 struct in6_addr **addr_p, struct in6_addr *saddr) 1082 { 1083 struct rt0_hdr *phdr, *ihdr; 1084 int hops; 1085 1086 ihdr = (struct rt0_hdr *) opt; 1087 1088 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1089 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1090 1091 hops = ihdr->rt_hdr.hdrlen >> 1; 1092 1093 if (hops > 1) 1094 memcpy(phdr->addr, ihdr->addr + 1, 1095 (hops - 1) * sizeof(struct in6_addr)); 1096 1097 phdr->addr[hops - 1] = **addr_p; 1098 *addr_p = ihdr->addr; 1099 1100 phdr->rt_hdr.nexthdr = *proto; 1101 *proto = NEXTHDR_ROUTING; 1102 } 1103 1104 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1105 struct ipv6_rt_hdr *opt, 1106 struct in6_addr **addr_p, struct in6_addr *saddr) 1107 { 1108 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1109 int plen, hops; 1110 1111 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1112 plen = (sr_ihdr->hdrlen + 1) << 3; 1113 1114 sr_phdr = skb_push(skb, plen); 1115 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1116 1117 hops = sr_ihdr->first_segment + 1; 1118 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1119 (hops - 1) * sizeof(struct in6_addr)); 1120 1121 sr_phdr->segments[0] = **addr_p; 1122 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1123 1124 if (sr_ihdr->hdrlen > hops * 2) { 1125 int tlvs_offset, tlvs_length; 1126 1127 tlvs_offset = (1 + hops * 2) << 3; 1128 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1129 memcpy((char *)sr_phdr + tlvs_offset, 1130 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1131 } 1132 1133 #ifdef CONFIG_IPV6_SEG6_HMAC 1134 if (sr_has_hmac(sr_phdr)) { 1135 struct net *net = NULL; 1136 1137 if (skb->dev) 1138 net = dev_net(skb->dev); 1139 else if (skb->sk) 1140 net = sock_net(skb->sk); 1141 1142 WARN_ON(!net); 1143 1144 if (net) 1145 seg6_push_hmac(net, saddr, sr_phdr); 1146 } 1147 #endif 1148 1149 sr_phdr->nexthdr = *proto; 1150 *proto = NEXTHDR_ROUTING; 1151 } 1152 1153 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1154 struct ipv6_rt_hdr *opt, 1155 struct in6_addr **addr_p, struct in6_addr *saddr) 1156 { 1157 switch (opt->type) { 1158 case IPV6_SRCRT_TYPE_0: 1159 case IPV6_SRCRT_STRICT: 1160 case IPV6_SRCRT_TYPE_2: 1161 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1162 break; 1163 case IPV6_SRCRT_TYPE_4: 1164 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1165 break; 1166 default: 1167 break; 1168 } 1169 } 1170 1171 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1172 { 1173 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1174 1175 memcpy(h, opt, ipv6_optlen(opt)); 1176 h->nexthdr = *proto; 1177 *proto = type; 1178 } 1179 1180 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1181 u8 *proto, 1182 struct in6_addr **daddr, struct in6_addr *saddr) 1183 { 1184 if (opt->srcrt) { 1185 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1186 /* 1187 * IPV6_RTHDRDSTOPTS is ignored 1188 * unless IPV6_RTHDR is set (RFC3542). 1189 */ 1190 if (opt->dst0opt) 1191 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1192 } 1193 if (opt->hopopt) 1194 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1195 } 1196 1197 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1198 { 1199 if (opt->dst1opt) 1200 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1201 } 1202 EXPORT_SYMBOL(ipv6_push_frag_opts); 1203 1204 struct ipv6_txoptions * 1205 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1206 { 1207 struct ipv6_txoptions *opt2; 1208 1209 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 1210 if (opt2) { 1211 long dif = (char *)opt2 - (char *)opt; 1212 memcpy(opt2, opt, opt->tot_len); 1213 if (opt2->hopopt) 1214 *((char **)&opt2->hopopt) += dif; 1215 if (opt2->dst0opt) 1216 *((char **)&opt2->dst0opt) += dif; 1217 if (opt2->dst1opt) 1218 *((char **)&opt2->dst1opt) += dif; 1219 if (opt2->srcrt) 1220 *((char **)&opt2->srcrt) += dif; 1221 refcount_set(&opt2->refcnt, 1); 1222 } 1223 return opt2; 1224 } 1225 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1226 1227 static void ipv6_renew_option(int renewtype, 1228 struct ipv6_opt_hdr **dest, 1229 struct ipv6_opt_hdr *old, 1230 struct ipv6_opt_hdr *new, 1231 int newtype, char **p) 1232 { 1233 struct ipv6_opt_hdr *src; 1234 1235 src = (renewtype == newtype ? new : old); 1236 if (!src) 1237 return; 1238 1239 memcpy(*p, src, ipv6_optlen(src)); 1240 *dest = (struct ipv6_opt_hdr *)*p; 1241 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1242 } 1243 1244 /** 1245 * ipv6_renew_options - replace a specific ext hdr with a new one. 1246 * 1247 * @sk: sock from which to allocate memory 1248 * @opt: original options 1249 * @newtype: option type to replace in @opt 1250 * @newopt: new option of type @newtype to replace (user-mem) 1251 * 1252 * Returns a new set of options which is a copy of @opt with the 1253 * option type @newtype replaced with @newopt. 1254 * 1255 * @opt may be NULL, in which case a new set of options is returned 1256 * containing just @newopt. 1257 * 1258 * @newopt may be NULL, in which case the specified option type is 1259 * not copied into the new set of options. 1260 * 1261 * The new set of options is allocated from the socket option memory 1262 * buffer of @sk. 1263 */ 1264 struct ipv6_txoptions * 1265 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1266 int newtype, struct ipv6_opt_hdr *newopt) 1267 { 1268 int tot_len = 0; 1269 char *p; 1270 struct ipv6_txoptions *opt2; 1271 1272 if (opt) { 1273 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1274 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1275 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1276 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1277 if (newtype != IPV6_RTHDR && opt->srcrt) 1278 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1279 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1280 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1281 } 1282 1283 if (newopt) 1284 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1285 1286 if (!tot_len) 1287 return NULL; 1288 1289 tot_len += sizeof(*opt2); 1290 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1291 if (!opt2) 1292 return ERR_PTR(-ENOBUFS); 1293 1294 memset(opt2, 0, tot_len); 1295 refcount_set(&opt2->refcnt, 1); 1296 opt2->tot_len = tot_len; 1297 p = (char *)(opt2 + 1); 1298 1299 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1300 (opt ? opt->hopopt : NULL), 1301 newopt, newtype, &p); 1302 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1303 (opt ? opt->dst0opt : NULL), 1304 newopt, newtype, &p); 1305 ipv6_renew_option(IPV6_RTHDR, 1306 (struct ipv6_opt_hdr **)&opt2->srcrt, 1307 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1308 newopt, newtype, &p); 1309 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1310 (opt ? opt->dst1opt : NULL), 1311 newopt, newtype, &p); 1312 1313 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1314 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1315 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1316 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1317 1318 return opt2; 1319 } 1320 1321 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1322 struct ipv6_txoptions *opt) 1323 { 1324 /* 1325 * ignore the dest before srcrt unless srcrt is being included. 1326 * --yoshfuji 1327 */ 1328 if (opt->dst0opt && !opt->srcrt) { 1329 if (opt_space != opt) { 1330 memcpy(opt_space, opt, sizeof(*opt_space)); 1331 opt = opt_space; 1332 } 1333 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1334 opt->dst0opt = NULL; 1335 } 1336 1337 return opt; 1338 } 1339 EXPORT_SYMBOL_GPL(__ipv6_fixup_options); 1340 1341 /** 1342 * fl6_update_dst - update flowi destination address with info given 1343 * by srcrt option, if any. 1344 * 1345 * @fl6: flowi6 for which daddr is to be updated 1346 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1347 * @orig: copy of original daddr address if modified 1348 * 1349 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1350 * and initial value of fl6->daddr set in orig 1351 */ 1352 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1353 const struct ipv6_txoptions *opt, 1354 struct in6_addr *orig) 1355 { 1356 if (!opt || !opt->srcrt) 1357 return NULL; 1358 1359 *orig = fl6->daddr; 1360 1361 switch (opt->srcrt->type) { 1362 case IPV6_SRCRT_TYPE_0: 1363 case IPV6_SRCRT_STRICT: 1364 case IPV6_SRCRT_TYPE_2: 1365 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1366 break; 1367 case IPV6_SRCRT_TYPE_4: 1368 { 1369 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1370 1371 fl6->daddr = srh->segments[srh->segments_left]; 1372 break; 1373 } 1374 default: 1375 return NULL; 1376 } 1377 1378 return orig; 1379 } 1380 EXPORT_SYMBOL_GPL(fl6_update_dst); 1381