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 65 static 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 99 drop: 100 kfree_skb_reason(skb, SKB_DROP_REASON_UNHANDLED_PROTO); 101 return false; 102 } 103 104 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff); 105 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff); 106 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff); 107 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff); 108 #if IS_ENABLED(CONFIG_IPV6_MIP6) 109 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff); 110 #endif 111 112 /* Parse tlv encoded option header (hop-by-hop or destination) */ 113 114 static 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; 221 bad: 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) 231 static 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 294 295 static 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), idev, 310 IPSTATS_MIB_INHDRERRORS); 311 fail_and_free: 312 kfree_skb(skb); 313 return -1; 314 } 315 316 extlen = (skb_transport_header(skb)[1] + 1) << 3; 317 if (extlen > 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, net->ipv6.sysctl.max_dst_opts_cnt)) { 326 skb->transport_header += extlen; 327 opt = IP6CB(skb); 328 #if IS_ENABLED(CONFIG_IPV6_MIP6) 329 opt->nhoff = dstbuf; 330 #else 331 opt->nhoff = opt->dst1; 332 #endif 333 return 1; 334 } 335 336 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 337 return -1; 338 } 339 340 static void seg6_update_csum(struct sk_buff *skb) 341 { 342 struct ipv6_sr_hdr *hdr; 343 struct in6_addr *addr; 344 __be32 from, to; 345 346 /* srh is at transport offset and seg_left is already decremented 347 * but daddr is not yet updated with next segment 348 */ 349 350 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 351 addr = hdr->segments + hdr->segments_left; 352 353 hdr->segments_left++; 354 from = *(__be32 *)hdr; 355 356 hdr->segments_left--; 357 to = *(__be32 *)hdr; 358 359 /* update skb csum with diff resulting from seg_left decrement */ 360 361 update_csum_diff4(skb, from, to); 362 363 /* compute csum diff between current and next segment and update */ 364 365 update_csum_diff16(skb, (__be32 *)(&ipv6_hdr(skb)->daddr), 366 (__be32 *)addr); 367 } 368 369 static int ipv6_srh_rcv(struct sk_buff *skb) 370 { 371 struct inet6_skb_parm *opt = IP6CB(skb); 372 struct net *net = dev_net(skb->dev); 373 struct ipv6_sr_hdr *hdr; 374 struct inet6_dev *idev; 375 struct in6_addr *addr; 376 int accept_seg6; 377 378 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 379 380 idev = __in6_dev_get(skb->dev); 381 382 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled), 383 READ_ONCE(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; 658 659 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route); 660 661 if (idev) 662 accept_source_route = min(accept_source_route, 663 READ_ONCE(idev->cnf.accept_source_route)); 664 665 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 666 !pskb_may_pull(skb, (skb_transport_offset(skb) + 667 ((skb_transport_header(skb)[1] + 1) << 3)))) { 668 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 669 kfree_skb(skb); 670 return -1; 671 } 672 673 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 674 675 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 676 skb->pkt_type != PACKET_HOST) { 677 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 678 kfree_skb(skb); 679 return -1; 680 } 681 682 switch (hdr->type) { 683 case IPV6_SRCRT_TYPE_4: 684 /* segment routing */ 685 return ipv6_srh_rcv(skb); 686 case IPV6_SRCRT_TYPE_3: 687 /* rpl segment routing */ 688 return ipv6_rpl_srh_rcv(skb); 689 default: 690 break; 691 } 692 693 looped_back: 694 if (hdr->segments_left == 0) { 695 switch (hdr->type) { 696 #if IS_ENABLED(CONFIG_IPV6_MIP6) 697 case IPV6_SRCRT_TYPE_2: 698 /* Silently discard type 2 header unless it was 699 * processed by own 700 */ 701 if (!addr) { 702 __IP6_INC_STATS(net, idev, 703 IPSTATS_MIB_INADDRERRORS); 704 kfree_skb(skb); 705 return -1; 706 } 707 break; 708 #endif 709 default: 710 break; 711 } 712 713 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 714 skb->transport_header += (hdr->hdrlen + 1) << 3; 715 opt->dst0 = opt->dst1; 716 opt->dst1 = 0; 717 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 718 return 1; 719 } 720 721 switch (hdr->type) { 722 #if IS_ENABLED(CONFIG_IPV6_MIP6) 723 case IPV6_SRCRT_TYPE_2: 724 if (accept_source_route < 0) 725 goto unknown_rh; 726 /* Silently discard invalid RTH type 2 */ 727 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 728 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 729 kfree_skb(skb); 730 return -1; 731 } 732 break; 733 #endif 734 default: 735 goto unknown_rh; 736 } 737 738 /* 739 * This is the routing header forwarding algorithm from 740 * RFC 2460, page 16. 741 */ 742 743 n = hdr->hdrlen >> 1; 744 745 if (hdr->segments_left > n) { 746 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 747 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 748 ((&hdr->segments_left) - 749 skb_network_header(skb))); 750 return -1; 751 } 752 753 /* We are about to mangle packet header. Be careful! 754 Do not damage packets queued somewhere. 755 */ 756 if (skb_cloned(skb)) { 757 /* the copy is a forwarded packet */ 758 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 759 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 760 IPSTATS_MIB_OUTDISCARDS); 761 kfree_skb(skb); 762 return -1; 763 } 764 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 765 } 766 767 if (skb->ip_summed == CHECKSUM_COMPLETE) 768 skb->ip_summed = CHECKSUM_NONE; 769 770 i = n - --hdr->segments_left; 771 772 rthdr = (struct rt0_hdr *) hdr; 773 addr = rthdr->addr; 774 addr += i - 1; 775 776 switch (hdr->type) { 777 #if IS_ENABLED(CONFIG_IPV6_MIP6) 778 case IPV6_SRCRT_TYPE_2: 779 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 780 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 781 IPPROTO_ROUTING) < 0) { 782 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 783 kfree_skb(skb); 784 return -1; 785 } 786 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 787 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 788 kfree_skb(skb); 789 return -1; 790 } 791 break; 792 #endif 793 default: 794 break; 795 } 796 797 if (ipv6_addr_is_multicast(addr)) { 798 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 799 kfree_skb(skb); 800 return -1; 801 } 802 803 swap(*addr, ipv6_hdr(skb)->daddr); 804 805 ip6_route_input(skb); 806 if (skb_dst(skb)->error) { 807 skb_push(skb, -skb_network_offset(skb)); 808 dst_input(skb); 809 return -1; 810 } 811 812 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 813 if (ipv6_hdr(skb)->hop_limit <= 1) { 814 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 815 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 816 0); 817 kfree_skb(skb); 818 return -1; 819 } 820 ipv6_hdr(skb)->hop_limit--; 821 goto looped_back; 822 } 823 824 skb_push(skb, -skb_network_offset(skb)); 825 dst_input(skb); 826 return -1; 827 828 unknown_rh: 829 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 830 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 831 (&hdr->type) - skb_network_header(skb)); 832 return -1; 833 } 834 835 static const struct inet6_protocol rthdr_protocol = { 836 .handler = ipv6_rthdr_rcv, 837 .flags = INET6_PROTO_NOPOLICY, 838 }; 839 840 static const struct inet6_protocol destopt_protocol = { 841 .handler = ipv6_destopt_rcv, 842 .flags = INET6_PROTO_NOPOLICY, 843 }; 844 845 static const struct inet6_protocol nodata_protocol = { 846 .handler = dst_discard, 847 .flags = INET6_PROTO_NOPOLICY, 848 }; 849 850 int __init ipv6_exthdrs_init(void) 851 { 852 int ret; 853 854 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 855 if (ret) 856 goto out; 857 858 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 859 if (ret) 860 goto out_rthdr; 861 862 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 863 if (ret) 864 goto out_destopt; 865 866 out: 867 return ret; 868 out_destopt: 869 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 870 out_rthdr: 871 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 872 goto out; 873 }; 874 875 void ipv6_exthdrs_exit(void) 876 { 877 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 878 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 879 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 880 } 881 882 /********************************** 883 Hop-by-hop options. 884 **********************************/ 885 886 /* Router Alert as of RFC 2711 */ 887 888 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 889 { 890 const unsigned char *nh = skb_network_header(skb); 891 892 if (nh[optoff + 1] == 2) { 893 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 894 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 895 return true; 896 } 897 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 898 nh[optoff + 1]); 899 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 900 return false; 901 } 902 903 /* IOAM */ 904 905 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 906 { 907 struct ioam6_trace_hdr *trace; 908 struct ioam6_namespace *ns; 909 struct ioam6_hdr *hdr; 910 911 /* Bad alignment (must be 4n-aligned) */ 912 if (optoff & 3) 913 goto drop; 914 915 /* Ignore if IOAM is not enabled on ingress */ 916 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled)) 917 goto ignore; 918 919 /* Truncated Option header */ 920 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 921 if (hdr->opt_len < 2) 922 goto drop; 923 924 switch (hdr->type) { 925 case IOAM6_TYPE_PREALLOC: 926 /* Truncated Pre-allocated Trace header */ 927 if (hdr->opt_len < 2 + sizeof(*trace)) 928 goto drop; 929 930 /* Malformed Pre-allocated Trace header */ 931 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 932 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 933 goto drop; 934 935 /* Ignore if the IOAM namespace is unknown */ 936 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id); 937 if (!ns) 938 goto ignore; 939 940 if (!skb_valid_dst(skb)) 941 ip6_route_input(skb); 942 943 /* About to mangle packet header */ 944 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) 945 goto drop; 946 947 /* Trace pointer may have changed */ 948 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) 949 + optoff + sizeof(*hdr)); 950 951 ioam6_fill_trace_data(skb, ns, trace, true); 952 953 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), 954 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); 955 break; 956 default: 957 break; 958 } 959 960 ignore: 961 return true; 962 963 drop: 964 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 965 return false; 966 } 967 968 /* Jumbo payload */ 969 970 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 971 { 972 const unsigned char *nh = skb_network_header(skb); 973 SKB_DR(reason); 974 u32 pkt_len; 975 976 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 977 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 978 nh[optoff+1]); 979 SKB_DR_SET(reason, IP_INHDR); 980 goto drop; 981 } 982 983 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 984 if (pkt_len <= IPV6_MAXPLEN) { 985 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 986 SKB_DROP_REASON_IP_INHDR); 987 return false; 988 } 989 if (ipv6_hdr(skb)->payload_len) { 990 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 991 SKB_DROP_REASON_IP_INHDR); 992 return false; 993 } 994 995 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 996 SKB_DR_SET(reason, PKT_TOO_SMALL); 997 goto drop; 998 } 999 1000 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 1001 goto drop; 1002 1003 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 1004 return true; 1005 1006 drop: 1007 kfree_skb_reason(skb, reason); 1008 return false; 1009 } 1010 1011 /* CALIPSO RFC 5570 */ 1012 1013 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1014 { 1015 const unsigned char *nh = skb_network_header(skb); 1016 1017 if (nh[optoff + 1] < 8) 1018 goto drop; 1019 1020 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1021 goto drop; 1022 1023 if (!calipso_validate(skb, nh + optoff)) 1024 goto drop; 1025 1026 return true; 1027 1028 drop: 1029 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1030 return false; 1031 } 1032 1033 int ipv6_parse_hopopts(struct sk_buff *skb) 1034 { 1035 struct inet6_skb_parm *opt = IP6CB(skb); 1036 struct net *net = dev_net(skb->dev); 1037 int extlen; 1038 1039 /* 1040 * skb_network_header(skb) is equal to skb->data, and 1041 * skb_network_header_len(skb) is always equal to 1042 * sizeof(struct ipv6hdr) by definition of 1043 * hop-by-hop options. 1044 */ 1045 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1046 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1047 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1048 fail_and_free: 1049 kfree_skb(skb); 1050 return -1; 1051 } 1052 1053 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1054 if (extlen > net->ipv6.sysctl.max_hbh_opts_len) 1055 goto fail_and_free; 1056 1057 opt->flags |= IP6SKB_HOPBYHOP; 1058 if (ip6_parse_tlv(true, skb, net->ipv6.sysctl.max_hbh_opts_cnt)) { 1059 skb->transport_header += extlen; 1060 opt = IP6CB(skb); 1061 opt->nhoff = sizeof(struct ipv6hdr); 1062 return 1; 1063 } 1064 return -1; 1065 } 1066 1067 /* 1068 * Creating outbound headers. 1069 * 1070 * "build" functions work when skb is filled from head to tail (datagram) 1071 * "push" functions work when headers are added from tail to head (tcp) 1072 * 1073 * In both cases we assume, that caller reserved enough room 1074 * for headers. 1075 */ 1076 1077 static void ipv6_push_rthdr0(struct sk_buff *skb, u8 *proto, 1078 struct ipv6_rt_hdr *opt, 1079 struct in6_addr **addr_p, struct in6_addr *saddr) 1080 { 1081 struct rt0_hdr *phdr, *ihdr; 1082 int hops; 1083 1084 ihdr = (struct rt0_hdr *) opt; 1085 1086 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1087 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1088 1089 hops = ihdr->rt_hdr.hdrlen >> 1; 1090 1091 if (hops > 1) 1092 memcpy(phdr->addr, ihdr->addr + 1, 1093 (hops - 1) * sizeof(struct in6_addr)); 1094 1095 phdr->addr[hops - 1] = **addr_p; 1096 *addr_p = ihdr->addr; 1097 1098 phdr->rt_hdr.nexthdr = *proto; 1099 *proto = NEXTHDR_ROUTING; 1100 } 1101 1102 static void ipv6_push_rthdr4(struct sk_buff *skb, u8 *proto, 1103 struct ipv6_rt_hdr *opt, 1104 struct in6_addr **addr_p, struct in6_addr *saddr) 1105 { 1106 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1107 int plen, hops; 1108 1109 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1110 plen = (sr_ihdr->hdrlen + 1) << 3; 1111 1112 sr_phdr = skb_push(skb, plen); 1113 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1114 1115 hops = sr_ihdr->first_segment + 1; 1116 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1117 (hops - 1) * sizeof(struct in6_addr)); 1118 1119 sr_phdr->segments[0] = **addr_p; 1120 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1121 1122 if (sr_ihdr->hdrlen > hops * 2) { 1123 int tlvs_offset, tlvs_length; 1124 1125 tlvs_offset = (1 + hops * 2) << 3; 1126 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1127 memcpy((char *)sr_phdr + tlvs_offset, 1128 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1129 } 1130 1131 #ifdef CONFIG_IPV6_SEG6_HMAC 1132 if (sr_has_hmac(sr_phdr)) { 1133 struct net *net = NULL; 1134 1135 if (skb->dev) 1136 net = dev_net(skb->dev); 1137 else if (skb->sk) 1138 net = sock_net(skb->sk); 1139 1140 WARN_ON(!net); 1141 1142 if (net) 1143 seg6_push_hmac(net, saddr, sr_phdr); 1144 } 1145 #endif 1146 1147 sr_phdr->nexthdr = *proto; 1148 *proto = NEXTHDR_ROUTING; 1149 } 1150 1151 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 1152 struct ipv6_rt_hdr *opt, 1153 struct in6_addr **addr_p, struct in6_addr *saddr) 1154 { 1155 switch (opt->type) { 1156 case IPV6_SRCRT_TYPE_0: 1157 case IPV6_SRCRT_STRICT: 1158 case IPV6_SRCRT_TYPE_2: 1159 ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1160 break; 1161 case IPV6_SRCRT_TYPE_4: 1162 ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1163 break; 1164 default: 1165 break; 1166 } 1167 } 1168 1169 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 1170 { 1171 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1172 1173 memcpy(h, opt, ipv6_optlen(opt)); 1174 h->nexthdr = *proto; 1175 *proto = type; 1176 } 1177 1178 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1179 u8 *proto, 1180 struct in6_addr **daddr, struct in6_addr *saddr) 1181 { 1182 if (opt->srcrt) { 1183 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1184 /* 1185 * IPV6_RTHDRDSTOPTS is ignored 1186 * unless IPV6_RTHDR is set (RFC3542). 1187 */ 1188 if (opt->dst0opt) 1189 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1190 } 1191 if (opt->hopopt) 1192 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1193 } 1194 1195 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 1196 { 1197 if (opt->dst1opt) 1198 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1199 } 1200 EXPORT_SYMBOL(ipv6_push_frag_opts); 1201 1202 struct ipv6_txoptions * 1203 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1204 { 1205 struct ipv6_txoptions *opt2; 1206 1207 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 1208 if (opt2) { 1209 long dif = (char *)opt2 - (char *)opt; 1210 memcpy(opt2, opt, opt->tot_len); 1211 if (opt2->hopopt) 1212 *((char **)&opt2->hopopt) += dif; 1213 if (opt2->dst0opt) 1214 *((char **)&opt2->dst0opt) += dif; 1215 if (opt2->dst1opt) 1216 *((char **)&opt2->dst1opt) += dif; 1217 if (opt2->srcrt) 1218 *((char **)&opt2->srcrt) += dif; 1219 refcount_set(&opt2->refcnt, 1); 1220 } 1221 return opt2; 1222 } 1223 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1224 1225 static void ipv6_renew_option(int renewtype, 1226 struct ipv6_opt_hdr **dest, 1227 struct ipv6_opt_hdr *old, 1228 struct ipv6_opt_hdr *new, 1229 int newtype, char **p) 1230 { 1231 struct ipv6_opt_hdr *src; 1232 1233 src = (renewtype == newtype ? new : old); 1234 if (!src) 1235 return; 1236 1237 memcpy(*p, src, ipv6_optlen(src)); 1238 *dest = (struct ipv6_opt_hdr *)*p; 1239 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1240 } 1241 1242 /** 1243 * ipv6_renew_options - replace a specific ext hdr with a new one. 1244 * 1245 * @sk: sock from which to allocate memory 1246 * @opt: original options 1247 * @newtype: option type to replace in @opt 1248 * @newopt: new option of type @newtype to replace (user-mem) 1249 * 1250 * Returns a new set of options which is a copy of @opt with the 1251 * option type @newtype replaced with @newopt. 1252 * 1253 * @opt may be NULL, in which case a new set of options is returned 1254 * containing just @newopt. 1255 * 1256 * @newopt may be NULL, in which case the specified option type is 1257 * not copied into the new set of options. 1258 * 1259 * The new set of options is allocated from the socket option memory 1260 * buffer of @sk. 1261 */ 1262 struct ipv6_txoptions * 1263 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1264 int newtype, struct ipv6_opt_hdr *newopt) 1265 { 1266 int tot_len = 0; 1267 char *p; 1268 struct ipv6_txoptions *opt2; 1269 1270 if (opt) { 1271 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1272 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1273 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1274 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1275 if (newtype != IPV6_RTHDR && opt->srcrt) 1276 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1277 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1278 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1279 } 1280 1281 if (newopt) 1282 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1283 1284 if (!tot_len) 1285 return NULL; 1286 1287 tot_len += sizeof(*opt2); 1288 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1289 if (!opt2) 1290 return ERR_PTR(-ENOBUFS); 1291 1292 memset(opt2, 0, tot_len); 1293 refcount_set(&opt2->refcnt, 1); 1294 opt2->tot_len = tot_len; 1295 p = (char *)(opt2 + 1); 1296 1297 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1298 (opt ? opt->hopopt : NULL), 1299 newopt, newtype, &p); 1300 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1301 (opt ? opt->dst0opt : NULL), 1302 newopt, newtype, &p); 1303 ipv6_renew_option(IPV6_RTHDR, 1304 (struct ipv6_opt_hdr **)&opt2->srcrt, 1305 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1306 newopt, newtype, &p); 1307 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1308 (opt ? opt->dst1opt : NULL), 1309 newopt, newtype, &p); 1310 1311 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1312 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1313 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1314 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1315 1316 return opt2; 1317 } 1318 1319 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1320 struct ipv6_txoptions *opt) 1321 { 1322 /* 1323 * ignore the dest before srcrt unless srcrt is being included. 1324 * --yoshfuji 1325 */ 1326 if (opt->dst0opt && !opt->srcrt) { 1327 if (opt_space != opt) { 1328 memcpy(opt_space, opt, sizeof(*opt_space)); 1329 opt = opt_space; 1330 } 1331 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1332 opt->dst0opt = NULL; 1333 } 1334 1335 return opt; 1336 } 1337 EXPORT_SYMBOL_GPL(__ipv6_fixup_options); 1338 1339 /** 1340 * fl6_update_dst - update flowi destination address with info given 1341 * by srcrt option, if any. 1342 * 1343 * @fl6: flowi6 for which daddr is to be updated 1344 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1345 * @orig: copy of original daddr address if modified 1346 * 1347 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 1348 * and initial value of fl6->daddr set in orig 1349 */ 1350 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 1351 const struct ipv6_txoptions *opt, 1352 struct in6_addr *orig) 1353 { 1354 if (!opt || !opt->srcrt) 1355 return NULL; 1356 1357 *orig = fl6->daddr; 1358 1359 switch (opt->srcrt->type) { 1360 case IPV6_SRCRT_TYPE_0: 1361 case IPV6_SRCRT_STRICT: 1362 case IPV6_SRCRT_TYPE_2: 1363 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1364 break; 1365 case IPV6_SRCRT_TYPE_4: 1366 { 1367 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1368 1369 fl6->daddr = srh->segments[srh->segments_left]; 1370 break; 1371 } 1372 default: 1373 return NULL; 1374 } 1375 1376 return orig; 1377 } 1378 EXPORT_SYMBOL_GPL(fl6_update_dst); 1379