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(dst)), 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 > 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 } 340 341 static 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 } 369 370 static 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); 382 383 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled), 384 READ_ONCE(idev->cnf.seg6_enabled)); 385 386 if (!accept_seg6) { 387 kfree_skb(skb); 388 return -1; 389 } 390 391 #ifdef CONFIG_IPV6_SEG6_HMAC 392 if (!seg6_hmac_validate_skb(skb)) { 393 kfree_skb(skb); 394 return -1; 395 } 396 #endif 397 398 looped_back: 399 if (hdr->segments_left == 0) { 400 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { 401 int offset = (hdr->hdrlen + 1) << 3; 402 403 skb_postpull_rcsum(skb, skb_network_header(skb), 404 skb_network_header_len(skb)); 405 skb_pull(skb, offset); 406 skb_postpull_rcsum(skb, skb_transport_header(skb), 407 offset); 408 409 skb_reset_network_header(skb); 410 skb_reset_transport_header(skb); 411 skb->encapsulation = 0; 412 if (hdr->nexthdr == NEXTHDR_IPV4) 413 skb->protocol = htons(ETH_P_IP); 414 __skb_tunnel_rx(skb, skb->dev, net); 415 416 netif_rx(skb); 417 return -1; 418 } 419 420 opt->srcrt = skb_network_header_len(skb); 421 opt->lastopt = opt->srcrt; 422 skb->transport_header += (hdr->hdrlen + 1) << 3; 423 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 424 425 return 1; 426 } 427 428 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 429 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 430 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 431 ((&hdr->segments_left) - 432 skb_network_header(skb))); 433 return -1; 434 } 435 436 if (skb_cloned(skb)) { 437 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 438 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 439 IPSTATS_MIB_OUTDISCARDS); 440 kfree_skb(skb); 441 return -1; 442 } 443 444 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 445 } 446 447 hdr->segments_left--; 448 addr = hdr->segments + hdr->segments_left; 449 450 skb_push(skb, sizeof(struct ipv6hdr)); 451 452 if (skb->ip_summed == CHECKSUM_COMPLETE) 453 seg6_update_csum(skb); 454 455 ipv6_hdr(skb)->daddr = *addr; 456 457 ip6_route_input(skb); 458 459 if (skb_dst(skb)->error) { 460 dst_input(skb); 461 return -1; 462 } 463 464 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 465 if (ipv6_hdr(skb)->hop_limit <= 1) { 466 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 467 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 468 ICMPV6_EXC_HOPLIMIT, 0); 469 kfree_skb(skb); 470 return -1; 471 } 472 ipv6_hdr(skb)->hop_limit--; 473 474 skb_pull(skb, sizeof(struct ipv6hdr)); 475 goto looped_back; 476 } 477 478 dst_input(skb); 479 480 return -1; 481 } 482 483 static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 484 { 485 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 486 struct inet6_skb_parm *opt = IP6CB(skb); 487 struct net *net = dev_net(skb->dev); 488 struct inet6_dev *idev; 489 struct ipv6hdr *oldhdr; 490 unsigned char *buf; 491 int accept_rpl_seg; 492 int i, err; 493 u64 n = 0; 494 u32 r; 495 496 idev = __in6_dev_get(skb->dev); 497 498 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled), 499 READ_ONCE(idev->cnf.rpl_seg_enabled)); 500 if (!accept_rpl_seg) { 501 kfree_skb(skb); 502 return -1; 503 } 504 505 looped_back: 506 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 507 508 if (hdr->segments_left == 0) { 509 if (hdr->nexthdr == NEXTHDR_IPV6) { 510 int offset = (hdr->hdrlen + 1) << 3; 511 512 skb_postpull_rcsum(skb, skb_network_header(skb), 513 skb_network_header_len(skb)); 514 skb_pull(skb, offset); 515 skb_postpull_rcsum(skb, skb_transport_header(skb), 516 offset); 517 518 skb_reset_network_header(skb); 519 skb_reset_transport_header(skb); 520 skb->encapsulation = 0; 521 522 __skb_tunnel_rx(skb, skb->dev, net); 523 524 netif_rx(skb); 525 return -1; 526 } 527 528 opt->srcrt = skb_network_header_len(skb); 529 opt->lastopt = opt->srcrt; 530 skb->transport_header += (hdr->hdrlen + 1) << 3; 531 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 532 533 return 1; 534 } 535 536 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 537 r = do_div(n, (16 - hdr->cmpri)); 538 /* checks if calculation was without remainder and n fits into 539 * unsigned char which is segments_left field. Should not be 540 * higher than that. 541 */ 542 if (r || (n + 1) > 255) { 543 kfree_skb(skb); 544 return -1; 545 } 546 547 if (hdr->segments_left > n + 1) { 548 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 549 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 550 ((&hdr->segments_left) - 551 skb_network_header(skb))); 552 return -1; 553 } 554 555 hdr->segments_left--; 556 i = n - hdr->segments_left; 557 558 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 559 if (unlikely(!buf)) { 560 kfree_skb(skb); 561 return -1; 562 } 563 564 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 565 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 566 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 567 568 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) { 569 kfree_skb(skb); 570 kfree(buf); 571 return -1; 572 } 573 574 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 575 if (err) { 576 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 577 kfree_skb(skb); 578 kfree(buf); 579 return -1; 580 } 581 582 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); 583 584 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 585 586 oldhdr = ipv6_hdr(skb); 587 588 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 589 skb_postpull_rcsum(skb, oldhdr, 590 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 591 if (unlikely(!hdr->segments_left)) { 592 if (pskb_expand_head(skb, sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3), 0, 593 GFP_ATOMIC)) { 594 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 595 kfree_skb(skb); 596 kfree(buf); 597 return -1; 598 } 599 600 oldhdr = ipv6_hdr(skb); 601 } 602 skb_push(skb, ((chdr->hdrlen + 1) << 3) + sizeof(struct ipv6hdr)); 603 skb_reset_network_header(skb); 604 skb_mac_header_rebuild(skb); 605 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 606 607 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 608 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 609 610 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 611 skb_postpush_rcsum(skb, ipv6_hdr(skb), 612 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 613 614 kfree(buf); 615 616 ip6_route_input(skb); 617 618 if (skb_dst(skb)->error) { 619 dst_input(skb); 620 return -1; 621 } 622 623 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 624 if (ipv6_hdr(skb)->hop_limit <= 1) { 625 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 626 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 627 ICMPV6_EXC_HOPLIMIT, 0); 628 kfree_skb(skb); 629 return -1; 630 } 631 ipv6_hdr(skb)->hop_limit--; 632 633 skb_pull(skb, sizeof(struct ipv6hdr)); 634 goto looped_back; 635 } 636 637 dst_input(skb); 638 639 return -1; 640 } 641 642 /******************************** 643 Routing header. 644 ********************************/ 645 646 /* called with rcu_read_lock() */ 647 static int ipv6_rthdr_rcv(struct sk_buff *skb) 648 { 649 struct inet6_dev *idev = __in6_dev_get(skb->dev); 650 struct inet6_skb_parm *opt = IP6CB(skb); 651 struct in6_addr *addr = NULL; 652 int n, i; 653 struct ipv6_rt_hdr *hdr; 654 struct rt0_hdr *rthdr; 655 struct net *net = dev_net(skb->dev); 656 int accept_source_route; 657 658 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route); 659 660 if (idev) 661 accept_source_route = min(accept_source_route, 662 READ_ONCE(idev->cnf.accept_source_route)); 663 664 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 665 !pskb_may_pull(skb, (skb_transport_offset(skb) + 666 ((skb_transport_header(skb)[1] + 1) << 3)))) { 667 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 668 kfree_skb(skb); 669 return -1; 670 } 671 672 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 673 674 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 675 skb->pkt_type != PACKET_HOST) { 676 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 677 kfree_skb(skb); 678 return -1; 679 } 680 681 switch (hdr->type) { 682 case IPV6_SRCRT_TYPE_4: 683 /* segment routing */ 684 return ipv6_srh_rcv(skb); 685 case IPV6_SRCRT_TYPE_3: 686 /* rpl segment routing */ 687 return ipv6_rpl_srh_rcv(skb); 688 default: 689 break; 690 } 691 692 looped_back: 693 if (hdr->segments_left == 0) { 694 switch (hdr->type) { 695 #if IS_ENABLED(CONFIG_IPV6_MIP6) 696 case IPV6_SRCRT_TYPE_2: 697 /* Silently discard type 2 header unless it was 698 * processed by own 699 */ 700 if (!addr) { 701 __IP6_INC_STATS(net, idev, 702 IPSTATS_MIB_INADDRERRORS); 703 kfree_skb(skb); 704 return -1; 705 } 706 break; 707 #endif 708 default: 709 break; 710 } 711 712 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 713 skb->transport_header += (hdr->hdrlen + 1) << 3; 714 opt->dst0 = opt->dst1; 715 opt->dst1 = 0; 716 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 717 return 1; 718 } 719 720 switch (hdr->type) { 721 #if IS_ENABLED(CONFIG_IPV6_MIP6) 722 case IPV6_SRCRT_TYPE_2: 723 if (accept_source_route < 0) 724 goto unknown_rh; 725 /* Silently discard invalid RTH type 2 */ 726 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 727 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 728 kfree_skb(skb); 729 return -1; 730 } 731 break; 732 #endif 733 default: 734 goto unknown_rh; 735 } 736 737 /* 738 * This is the routing header forwarding algorithm from 739 * RFC 2460, page 16. 740 */ 741 742 n = hdr->hdrlen >> 1; 743 744 if (hdr->segments_left > n) { 745 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 746 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 747 ((&hdr->segments_left) - 748 skb_network_header(skb))); 749 return -1; 750 } 751 752 /* We are about to mangle packet header. Be careful! 753 Do not damage packets queued somewhere. 754 */ 755 if (skb_cloned(skb)) { 756 /* the copy is a forwarded packet */ 757 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 758 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 759 IPSTATS_MIB_OUTDISCARDS); 760 kfree_skb(skb); 761 return -1; 762 } 763 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 764 } 765 766 if (skb->ip_summed == CHECKSUM_COMPLETE) 767 skb->ip_summed = CHECKSUM_NONE; 768 769 i = n - --hdr->segments_left; 770 771 rthdr = (struct rt0_hdr *) hdr; 772 addr = rthdr->addr; 773 addr += i - 1; 774 775 switch (hdr->type) { 776 #if IS_ENABLED(CONFIG_IPV6_MIP6) 777 case IPV6_SRCRT_TYPE_2: 778 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 779 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 780 IPPROTO_ROUTING) < 0) { 781 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 782 kfree_skb(skb); 783 return -1; 784 } 785 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) { 786 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 787 kfree_skb(skb); 788 return -1; 789 } 790 break; 791 #endif 792 default: 793 break; 794 } 795 796 if (ipv6_addr_is_multicast(addr)) { 797 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 798 kfree_skb(skb); 799 return -1; 800 } 801 802 swap(*addr, ipv6_hdr(skb)->daddr); 803 804 ip6_route_input(skb); 805 if (skb_dst(skb)->error) { 806 skb_push(skb, -skb_network_offset(skb)); 807 dst_input(skb); 808 return -1; 809 } 810 811 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 812 if (ipv6_hdr(skb)->hop_limit <= 1) { 813 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 814 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 815 0); 816 kfree_skb(skb); 817 return -1; 818 } 819 ipv6_hdr(skb)->hop_limit--; 820 goto looped_back; 821 } 822 823 skb_push(skb, -skb_network_offset(skb)); 824 dst_input(skb); 825 return -1; 826 827 unknown_rh: 828 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 829 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 830 (&hdr->type) - skb_network_header(skb)); 831 return -1; 832 } 833 834 static const struct inet6_protocol rthdr_protocol = { 835 .handler = ipv6_rthdr_rcv, 836 .flags = INET6_PROTO_NOPOLICY, 837 }; 838 839 static const struct inet6_protocol destopt_protocol = { 840 .handler = ipv6_destopt_rcv, 841 .flags = INET6_PROTO_NOPOLICY, 842 }; 843 844 static const struct inet6_protocol nodata_protocol = { 845 .handler = dst_discard, 846 .flags = INET6_PROTO_NOPOLICY, 847 }; 848 849 int __init ipv6_exthdrs_init(void) 850 { 851 int ret; 852 853 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 854 if (ret) 855 goto out; 856 857 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 858 if (ret) 859 goto out_rthdr; 860 861 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 862 if (ret) 863 goto out_destopt; 864 865 out: 866 return ret; 867 out_destopt: 868 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 869 out_rthdr: 870 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 871 goto out; 872 }; 873 874 void ipv6_exthdrs_exit(void) 875 { 876 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 877 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 878 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 879 } 880 881 /********************************** 882 Hop-by-hop options. 883 **********************************/ 884 885 /* Router Alert as of RFC 2711 */ 886 887 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 888 { 889 const unsigned char *nh = skb_network_header(skb); 890 891 if (nh[optoff + 1] == 2) { 892 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 893 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 894 return true; 895 } 896 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 897 nh[optoff + 1]); 898 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 899 return false; 900 } 901 902 /* IOAM */ 903 904 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 905 { 906 struct ioam6_trace_hdr *trace; 907 struct ioam6_namespace *ns; 908 struct ioam6_hdr *hdr; 909 910 /* Bad alignment (must be 4n-aligned) */ 911 if (optoff & 3) 912 goto drop; 913 914 /* Ignore if IOAM is not enabled on ingress */ 915 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled)) 916 goto ignore; 917 918 /* Truncated Option header */ 919 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 920 if (hdr->opt_len < 2) 921 goto drop; 922 923 switch (hdr->type) { 924 case IOAM6_TYPE_PREALLOC: 925 /* Truncated Pre-allocated Trace header */ 926 if (hdr->opt_len < 2 + sizeof(*trace)) 927 goto drop; 928 929 /* Malformed Pre-allocated Trace header */ 930 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 931 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 932 goto drop; 933 934 /* Ignore if the IOAM namespace is unknown */ 935 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id); 936 if (!ns) 937 goto ignore; 938 939 if (!skb_valid_dst(skb)) 940 ip6_route_input(skb); 941 942 /* About to mangle packet header */ 943 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) 944 goto drop; 945 946 /* Trace pointer may have changed */ 947 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) 948 + optoff + sizeof(*hdr)); 949 950 ioam6_fill_trace_data(skb, ns, trace, true); 951 952 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), 953 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); 954 break; 955 default: 956 break; 957 } 958 959 ignore: 960 return true; 961 962 drop: 963 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 964 return false; 965 } 966 967 /* Jumbo payload */ 968 969 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 970 { 971 const unsigned char *nh = skb_network_header(skb); 972 SKB_DR(reason); 973 u32 pkt_len; 974 975 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 976 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 977 nh[optoff+1]); 978 SKB_DR_SET(reason, IP_INHDR); 979 goto drop; 980 } 981 982 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 983 if (pkt_len <= IPV6_MAXPLEN) { 984 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 985 SKB_DROP_REASON_IP_INHDR); 986 return false; 987 } 988 if (ipv6_hdr(skb)->payload_len) { 989 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 990 SKB_DROP_REASON_IP_INHDR); 991 return false; 992 } 993 994 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 995 SKB_DR_SET(reason, PKT_TOO_SMALL); 996 goto drop; 997 } 998 999 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 1000 goto drop; 1001 1002 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 1003 return true; 1004 1005 drop: 1006 kfree_skb_reason(skb, reason); 1007 return false; 1008 } 1009 1010 /* CALIPSO RFC 5570 */ 1011 1012 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1013 { 1014 const unsigned char *nh = skb_network_header(skb); 1015 1016 if (nh[optoff + 1] < 8) 1017 goto drop; 1018 1019 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1020 goto drop; 1021 1022 if (!calipso_validate(skb, nh + optoff)) 1023 goto drop; 1024 1025 return true; 1026 1027 drop: 1028 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1029 return false; 1030 } 1031 1032 int ipv6_parse_hopopts(struct sk_buff *skb) 1033 { 1034 struct inet6_skb_parm *opt = IP6CB(skb); 1035 struct net *net = dev_net(skb->dev); 1036 int extlen; 1037 1038 /* 1039 * skb_network_header(skb) is equal to skb->data, and 1040 * skb_network_header_len(skb) is always equal to 1041 * sizeof(struct ipv6hdr) by definition of 1042 * hop-by-hop options. 1043 */ 1044 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1045 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1046 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1047 fail_and_free: 1048 kfree_skb(skb); 1049 return -1; 1050 } 1051 1052 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1053 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len)) 1054 goto fail_and_free; 1055 1056 opt->flags |= IP6SKB_HOPBYHOP; 1057 if (ip6_parse_tlv(true, skb, 1058 READ_ONCE(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 u8 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 return NEXTHDR_ROUTING; 1100 } 1101 1102 static u8 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 return NEXTHDR_ROUTING; 1149 } 1150 1151 static u8 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 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1160 break; 1161 case IPV6_SRCRT_TYPE_4: 1162 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1163 break; 1164 default: 1165 break; 1166 } 1167 return proto; 1168 } 1169 1170 static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt) 1171 { 1172 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1173 1174 memcpy(h, opt, ipv6_optlen(opt)); 1175 h->nexthdr = proto; 1176 return type; 1177 } 1178 1179 u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1180 u8 proto, 1181 struct in6_addr **daddr, struct in6_addr *saddr) 1182 { 1183 if (opt->srcrt) { 1184 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1185 /* 1186 * IPV6_RTHDRDSTOPTS is ignored 1187 * unless IPV6_RTHDR is set (RFC3542). 1188 */ 1189 if (opt->dst0opt) 1190 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1191 } 1192 if (opt->hopopt) 1193 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1194 return proto; 1195 } 1196 1197 u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto) 1198 { 1199 if (opt->dst1opt) 1200 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1201 return proto; 1202 } 1203 EXPORT_SYMBOL(ipv6_push_frag_opts); 1204 1205 struct ipv6_txoptions * 1206 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1207 { 1208 struct ipv6_txoptions *opt2; 1209 1210 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC); 1211 if (opt2) { 1212 long dif = (char *)opt2 - (char *)opt; 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 * Return: NULL if no srcrt or invalid srcrt type, 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->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