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 if (!idev) { 383 kfree_skb(skb); 384 return -1; 385 } 386 387 accept_seg6 = min(READ_ONCE(net->ipv6.devconf_all->seg6_enabled), 388 READ_ONCE(idev->cnf.seg6_enabled)); 389 390 if (!accept_seg6) { 391 kfree_skb(skb); 392 return -1; 393 } 394 395 #ifdef CONFIG_IPV6_SEG6_HMAC 396 if (!seg6_hmac_validate_skb(skb)) { 397 kfree_skb(skb); 398 return -1; 399 } 400 #endif 401 402 looped_back: 403 if (hdr->segments_left == 0) { 404 if (hdr->nexthdr == NEXTHDR_IPV6 || hdr->nexthdr == NEXTHDR_IPV4) { 405 int offset = (hdr->hdrlen + 1) << 3; 406 407 skb_postpull_rcsum(skb, skb_network_header(skb), 408 skb_network_header_len(skb)); 409 skb_pull(skb, offset); 410 skb_postpull_rcsum(skb, skb_transport_header(skb), 411 offset); 412 413 skb_reset_network_header(skb); 414 skb_reset_transport_header(skb); 415 skb->encapsulation = 0; 416 if (hdr->nexthdr == NEXTHDR_IPV4) 417 skb->protocol = htons(ETH_P_IP); 418 __skb_tunnel_rx(skb, skb->dev, net); 419 420 netif_rx(skb); 421 return -1; 422 } 423 424 opt->srcrt = skb_network_header_len(skb); 425 opt->lastopt = opt->srcrt; 426 skb->transport_header += (hdr->hdrlen + 1) << 3; 427 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 428 429 return 1; 430 } 431 432 if (hdr->segments_left >= (hdr->hdrlen >> 1)) { 433 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 434 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 435 ((&hdr->segments_left) - 436 skb_network_header(skb))); 437 return -1; 438 } 439 440 if (skb_cloned(skb)) { 441 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 442 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 443 IPSTATS_MIB_OUTDISCARDS); 444 kfree_skb(skb); 445 return -1; 446 } 447 448 hdr = (struct ipv6_sr_hdr *)skb_transport_header(skb); 449 } 450 451 hdr->segments_left--; 452 addr = hdr->segments + hdr->segments_left; 453 454 skb_push(skb, sizeof(struct ipv6hdr)); 455 456 if (skb->ip_summed == CHECKSUM_COMPLETE) 457 seg6_update_csum(skb); 458 459 ipv6_hdr(skb)->daddr = *addr; 460 461 ip6_route_input(skb); 462 463 if (skb_dst(skb)->error) { 464 dst_input(skb); 465 return -1; 466 } 467 468 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 469 if (ipv6_hdr(skb)->hop_limit <= 1) { 470 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 471 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 472 ICMPV6_EXC_HOPLIMIT, 0); 473 kfree_skb(skb); 474 return -1; 475 } 476 ipv6_hdr(skb)->hop_limit--; 477 478 skb_pull(skb, sizeof(struct ipv6hdr)); 479 goto looped_back; 480 } 481 482 dst_input(skb); 483 484 return -1; 485 } 486 487 static int ipv6_rpl_srh_rcv(struct sk_buff *skb) 488 { 489 struct ipv6_rpl_sr_hdr *hdr, *ohdr, *chdr; 490 struct inet6_skb_parm *opt = IP6CB(skb); 491 struct net *net = dev_net(skb->dev); 492 struct inet6_dev *idev; 493 struct ipv6hdr *oldhdr; 494 unsigned int chdr_len; 495 unsigned char *buf; 496 int accept_rpl_seg; 497 int i, err; 498 u64 n = 0; 499 u32 r; 500 501 idev = __in6_dev_get(skb->dev); 502 503 accept_rpl_seg = min(READ_ONCE(net->ipv6.devconf_all->rpl_seg_enabled), 504 READ_ONCE(idev->cnf.rpl_seg_enabled)); 505 if (!accept_rpl_seg) { 506 kfree_skb(skb); 507 return -1; 508 } 509 510 looped_back: 511 hdr = (struct ipv6_rpl_sr_hdr *)skb_transport_header(skb); 512 513 if (hdr->segments_left == 0) { 514 if (hdr->nexthdr == NEXTHDR_IPV6) { 515 int offset = (hdr->hdrlen + 1) << 3; 516 517 skb_postpull_rcsum(skb, skb_network_header(skb), 518 skb_network_header_len(skb)); 519 skb_pull(skb, offset); 520 skb_postpull_rcsum(skb, skb_transport_header(skb), 521 offset); 522 523 skb_reset_network_header(skb); 524 skb_reset_transport_header(skb); 525 skb->encapsulation = 0; 526 527 __skb_tunnel_rx(skb, skb->dev, net); 528 529 netif_rx(skb); 530 return -1; 531 } 532 533 opt->srcrt = skb_network_header_len(skb); 534 opt->lastopt = opt->srcrt; 535 skb->transport_header += (hdr->hdrlen + 1) << 3; 536 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 537 538 return 1; 539 } 540 541 n = (hdr->hdrlen << 3) - hdr->pad - (16 - hdr->cmpre); 542 r = do_div(n, (16 - hdr->cmpri)); 543 /* checks if calculation was without remainder and n fits into 544 * unsigned char which is segments_left field. Should not be 545 * higher than that. 546 */ 547 if (r || (n + 1) > 255) { 548 kfree_skb(skb); 549 return -1; 550 } 551 552 if (hdr->segments_left > n + 1) { 553 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 554 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 555 ((&hdr->segments_left) - 556 skb_network_header(skb))); 557 return -1; 558 } 559 560 hdr->segments_left--; 561 i = n - hdr->segments_left; 562 563 buf = kcalloc(struct_size(hdr, segments.addr, n + 2), 2, GFP_ATOMIC); 564 if (unlikely(!buf)) { 565 kfree_skb(skb); 566 return -1; 567 } 568 569 ohdr = (struct ipv6_rpl_sr_hdr *)buf; 570 ipv6_rpl_srh_decompress(ohdr, hdr, &ipv6_hdr(skb)->daddr, n); 571 chdr = (struct ipv6_rpl_sr_hdr *)(buf + ((ohdr->hdrlen + 1) << 3)); 572 573 if (ipv6_addr_is_multicast(&ohdr->rpl_segaddr[i])) { 574 kfree_skb(skb); 575 kfree(buf); 576 return -1; 577 } 578 579 err = ipv6_chk_rpl_srh_loop(net, ohdr->rpl_segaddr, n + 1); 580 if (err) { 581 icmpv6_send(skb, ICMPV6_PARAMPROB, 0, 0); 582 kfree_skb(skb); 583 kfree(buf); 584 return -1; 585 } 586 587 swap(ipv6_hdr(skb)->daddr, ohdr->rpl_segaddr[i]); 588 589 ipv6_rpl_srh_compress(chdr, ohdr, &ipv6_hdr(skb)->daddr, n); 590 591 oldhdr = ipv6_hdr(skb); 592 593 skb_pull(skb, ((hdr->hdrlen + 1) << 3)); 594 skb_postpull_rcsum(skb, oldhdr, 595 sizeof(struct ipv6hdr) + ((hdr->hdrlen + 1) << 3)); 596 chdr_len = sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3); 597 if (unlikely(!hdr->segments_left || 598 skb_headroom(skb) < chdr_len + skb->mac_len)) { 599 if (pskb_expand_head(skb, chdr_len + skb->mac_len, 0, 600 GFP_ATOMIC)) { 601 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_OUTDISCARDS); 602 kfree_skb(skb); 603 kfree(buf); 604 return -1; 605 } 606 607 oldhdr = ipv6_hdr(skb); 608 } 609 skb_push(skb, chdr_len); 610 skb_reset_network_header(skb); 611 skb_mac_header_rebuild(skb); 612 skb_set_transport_header(skb, sizeof(struct ipv6hdr)); 613 614 memmove(ipv6_hdr(skb), oldhdr, sizeof(struct ipv6hdr)); 615 memcpy(skb_transport_header(skb), chdr, (chdr->hdrlen + 1) << 3); 616 617 ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); 618 skb_postpush_rcsum(skb, ipv6_hdr(skb), 619 sizeof(struct ipv6hdr) + ((chdr->hdrlen + 1) << 3)); 620 621 kfree(buf); 622 623 ip6_route_input(skb); 624 625 if (skb_dst(skb)->error) { 626 dst_input(skb); 627 return -1; 628 } 629 630 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 631 if (ipv6_hdr(skb)->hop_limit <= 1) { 632 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 633 icmpv6_send(skb, ICMPV6_TIME_EXCEED, 634 ICMPV6_EXC_HOPLIMIT, 0); 635 kfree_skb(skb); 636 return -1; 637 } 638 ipv6_hdr(skb)->hop_limit--; 639 640 skb_pull(skb, sizeof(struct ipv6hdr)); 641 goto looped_back; 642 } 643 644 dst_input(skb); 645 646 return -1; 647 } 648 649 /******************************** 650 Routing header. 651 ********************************/ 652 653 /* called with rcu_read_lock() */ 654 static int ipv6_rthdr_rcv(struct sk_buff *skb) 655 { 656 struct inet6_dev *idev = __in6_dev_get(skb->dev); 657 struct inet6_skb_parm *opt = IP6CB(skb); 658 struct in6_addr *addr = NULL; 659 int n, i; 660 struct ipv6_rt_hdr *hdr; 661 struct rt0_hdr *rthdr; 662 struct net *net = dev_net(skb->dev); 663 int accept_source_route; 664 665 accept_source_route = READ_ONCE(net->ipv6.devconf_all->accept_source_route); 666 667 if (idev) 668 accept_source_route = min(accept_source_route, 669 READ_ONCE(idev->cnf.accept_source_route)); 670 671 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 672 !pskb_may_pull(skb, (skb_transport_offset(skb) + 673 ((skb_transport_header(skb)[1] + 1) << 3)))) { 674 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 675 kfree_skb(skb); 676 return -1; 677 } 678 679 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 680 681 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 682 skb->pkt_type != PACKET_HOST) { 683 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 684 kfree_skb(skb); 685 return -1; 686 } 687 688 switch (hdr->type) { 689 case IPV6_SRCRT_TYPE_4: 690 /* segment routing */ 691 return ipv6_srh_rcv(skb); 692 case IPV6_SRCRT_TYPE_3: 693 /* rpl segment routing */ 694 return ipv6_rpl_srh_rcv(skb); 695 default: 696 break; 697 } 698 699 looped_back: 700 if (hdr->segments_left == 0) { 701 switch (hdr->type) { 702 #if IS_ENABLED(CONFIG_IPV6_MIP6) 703 case IPV6_SRCRT_TYPE_2: 704 /* Silently discard type 2 header unless it was 705 * processed by own 706 */ 707 if (!addr) { 708 __IP6_INC_STATS(net, idev, 709 IPSTATS_MIB_INADDRERRORS); 710 kfree_skb(skb); 711 return -1; 712 } 713 break; 714 #endif 715 default: 716 break; 717 } 718 719 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 720 skb->transport_header += (hdr->hdrlen + 1) << 3; 721 opt->dst0 = opt->dst1; 722 opt->dst1 = 0; 723 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 724 return 1; 725 } 726 727 switch (hdr->type) { 728 #if IS_ENABLED(CONFIG_IPV6_MIP6) 729 case IPV6_SRCRT_TYPE_2: 730 if (accept_source_route < 0) 731 goto unknown_rh; 732 /* Silently discard invalid RTH type 2 */ 733 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 734 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 735 kfree_skb(skb); 736 return -1; 737 } 738 break; 739 #endif 740 default: 741 goto unknown_rh; 742 } 743 744 /* 745 * This is the routing header forwarding algorithm from 746 * RFC 2460, page 16. 747 */ 748 749 n = hdr->hdrlen >> 1; 750 751 if (hdr->segments_left > n) { 752 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 753 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 754 ((&hdr->segments_left) - 755 skb_network_header(skb))); 756 return -1; 757 } 758 759 /* We are about to mangle packet header. Be careful! 760 Do not damage packets queued somewhere. 761 */ 762 if (skb_cloned(skb)) { 763 /* the copy is a forwarded packet */ 764 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 765 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 766 IPSTATS_MIB_OUTDISCARDS); 767 kfree_skb(skb); 768 return -1; 769 } 770 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 771 } 772 773 if (skb->ip_summed == CHECKSUM_COMPLETE) 774 skb->ip_summed = CHECKSUM_NONE; 775 776 i = n - --hdr->segments_left; 777 778 rthdr = (struct rt0_hdr *) hdr; 779 addr = rthdr->addr; 780 addr += i - 1; 781 782 switch (hdr->type) { 783 #if IS_ENABLED(CONFIG_IPV6_MIP6) 784 case IPV6_SRCRT_TYPE_2: 785 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 786 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 787 IPPROTO_ROUTING) < 0) { 788 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 789 kfree_skb(skb); 790 return -1; 791 } 792 if (!ipv6_chk_home_addr(skb_dst_dev_net(skb), addr)) { 793 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 794 kfree_skb(skb); 795 return -1; 796 } 797 break; 798 #endif 799 default: 800 break; 801 } 802 803 if (ipv6_addr_is_multicast(addr)) { 804 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INADDRERRORS); 805 kfree_skb(skb); 806 return -1; 807 } 808 809 swap(*addr, ipv6_hdr(skb)->daddr); 810 811 ip6_route_input(skb); 812 if (skb_dst(skb)->error) { 813 skb_push(skb, -skb_network_offset(skb)); 814 dst_input(skb); 815 return -1; 816 } 817 818 if (skb_dst_dev(skb)->flags & IFF_LOOPBACK) { 819 if (ipv6_hdr(skb)->hop_limit <= 1) { 820 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 821 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 822 0); 823 kfree_skb(skb); 824 return -1; 825 } 826 ipv6_hdr(skb)->hop_limit--; 827 goto looped_back; 828 } 829 830 skb_push(skb, -skb_network_offset(skb)); 831 dst_input(skb); 832 return -1; 833 834 unknown_rh: 835 __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS); 836 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 837 (&hdr->type) - skb_network_header(skb)); 838 return -1; 839 } 840 841 static const struct inet6_protocol rthdr_protocol = { 842 .handler = ipv6_rthdr_rcv, 843 .flags = INET6_PROTO_NOPOLICY, 844 }; 845 846 static const struct inet6_protocol destopt_protocol = { 847 .handler = ipv6_destopt_rcv, 848 .flags = INET6_PROTO_NOPOLICY, 849 }; 850 851 static const struct inet6_protocol nodata_protocol = { 852 .handler = dst_discard, 853 .flags = INET6_PROTO_NOPOLICY, 854 }; 855 856 int __init ipv6_exthdrs_init(void) 857 { 858 int ret; 859 860 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 861 if (ret) 862 goto out; 863 864 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 865 if (ret) 866 goto out_rthdr; 867 868 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 869 if (ret) 870 goto out_destopt; 871 872 out: 873 return ret; 874 out_destopt: 875 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 876 out_rthdr: 877 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 878 goto out; 879 }; 880 881 void ipv6_exthdrs_exit(void) 882 { 883 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 884 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 885 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 886 } 887 888 /********************************** 889 Hop-by-hop options. 890 **********************************/ 891 892 /* Router Alert as of RFC 2711 */ 893 894 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 895 { 896 const unsigned char *nh = skb_network_header(skb); 897 898 if (nh[optoff + 1] == 2) { 899 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 900 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 901 return true; 902 } 903 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 904 nh[optoff + 1]); 905 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 906 return false; 907 } 908 909 /* IOAM */ 910 911 static bool ipv6_hop_ioam(struct sk_buff *skb, int optoff) 912 { 913 struct ioam6_trace_hdr *trace; 914 struct ioam6_namespace *ns; 915 struct ioam6_hdr *hdr; 916 917 /* Bad alignment (must be 4n-aligned) */ 918 if (optoff & 3) 919 goto drop; 920 921 /* Ignore if IOAM is not enabled on ingress */ 922 if (!READ_ONCE(__in6_dev_get(skb->dev)->cnf.ioam6_enabled)) 923 goto ignore; 924 925 /* Truncated Option header */ 926 hdr = (struct ioam6_hdr *)(skb_network_header(skb) + optoff); 927 if (hdr->opt_len < 2) 928 goto drop; 929 930 switch (hdr->type) { 931 case IOAM6_TYPE_PREALLOC: 932 /* Truncated Pre-allocated Trace header */ 933 if (hdr->opt_len < 2 + sizeof(*trace)) 934 goto drop; 935 936 /* Malformed Pre-allocated Trace header */ 937 trace = (struct ioam6_trace_hdr *)((u8 *)hdr + sizeof(*hdr)); 938 if (hdr->opt_len < 2 + sizeof(*trace) + trace->remlen * 4) 939 goto drop; 940 941 /* Inconsistent Pre-allocated Trace header */ 942 if (trace->nodelen != 943 ioam6_trace_compute_nodelen(be32_to_cpu(trace->type_be32))) 944 goto drop; 945 946 /* Ignore if the IOAM namespace is unknown */ 947 ns = ioam6_namespace(dev_net(skb->dev), trace->namespace_id); 948 if (!ns) 949 goto ignore; 950 951 if (!skb_valid_dst(skb)) 952 ip6_route_input(skb); 953 954 /* About to mangle packet header */ 955 if (skb_ensure_writable(skb, optoff + 2 + hdr->opt_len)) 956 goto drop; 957 958 /* Trace pointer may have changed */ 959 trace = (struct ioam6_trace_hdr *)(skb_network_header(skb) 960 + optoff + sizeof(*hdr)); 961 962 ioam6_fill_trace_data(skb, ns, trace, true); 963 964 ioam6_event(IOAM6_EVENT_TRACE, dev_net(skb->dev), 965 GFP_ATOMIC, (void *)trace, hdr->opt_len - 2); 966 break; 967 default: 968 break; 969 } 970 971 ignore: 972 return true; 973 974 drop: 975 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 976 return false; 977 } 978 979 /* Jumbo payload */ 980 981 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 982 { 983 const unsigned char *nh = skb_network_header(skb); 984 SKB_DR(reason); 985 u32 pkt_len; 986 987 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 988 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 989 nh[optoff+1]); 990 SKB_DR_SET(reason, IP_INHDR); 991 goto drop; 992 } 993 994 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 995 if (pkt_len <= IPV6_MAXPLEN) { 996 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff + 2, 997 SKB_DROP_REASON_IP_INHDR); 998 return false; 999 } 1000 if (ipv6_hdr(skb)->payload_len) { 1001 icmpv6_param_prob_reason(skb, ICMPV6_HDR_FIELD, optoff, 1002 SKB_DROP_REASON_IP_INHDR); 1003 return false; 1004 } 1005 1006 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 1007 SKB_DR_SET(reason, PKT_TOO_SMALL); 1008 goto drop; 1009 } 1010 1011 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 1012 goto drop; 1013 1014 IP6CB(skb)->flags |= IP6SKB_JUMBOGRAM; 1015 return true; 1016 1017 drop: 1018 kfree_skb_reason(skb, reason); 1019 return false; 1020 } 1021 1022 /* CALIPSO RFC 5570 */ 1023 1024 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 1025 { 1026 const unsigned char *nh = skb_network_header(skb); 1027 1028 if (nh[optoff + 1] < 8) 1029 goto drop; 1030 1031 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 1032 goto drop; 1033 1034 if (!calipso_validate(skb, nh + optoff)) 1035 goto drop; 1036 1037 return true; 1038 1039 drop: 1040 kfree_skb_reason(skb, SKB_DROP_REASON_IP_INHDR); 1041 return false; 1042 } 1043 1044 int ipv6_parse_hopopts(struct sk_buff *skb) 1045 { 1046 struct inet6_skb_parm *opt = IP6CB(skb); 1047 struct net *net = dev_net(skb->dev); 1048 int extlen; 1049 1050 /* 1051 * skb_network_header(skb) is equal to skb->data, and 1052 * skb_network_header_len(skb) is always equal to 1053 * sizeof(struct ipv6hdr) by definition of 1054 * hop-by-hop options. 1055 */ 1056 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 1057 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 1058 ((skb_transport_header(skb)[1] + 1) << 3)))) { 1059 fail_and_free: 1060 kfree_skb(skb); 1061 return -1; 1062 } 1063 1064 extlen = (skb_transport_header(skb)[1] + 1) << 3; 1065 if (extlen > READ_ONCE(net->ipv6.sysctl.max_hbh_opts_len)) 1066 goto fail_and_free; 1067 1068 opt->flags |= IP6SKB_HOPBYHOP; 1069 if (ip6_parse_tlv(true, skb, 1070 READ_ONCE(net->ipv6.sysctl.max_hbh_opts_cnt))) { 1071 skb->transport_header += extlen; 1072 opt = IP6CB(skb); 1073 opt->nhoff = sizeof(struct ipv6hdr); 1074 return 1; 1075 } 1076 return -1; 1077 } 1078 1079 /* 1080 * Creating outbound headers. 1081 * 1082 * "build" functions work when skb is filled from head to tail (datagram) 1083 * "push" functions work when headers are added from tail to head (tcp) 1084 * 1085 * In both cases we assume, that caller reserved enough room 1086 * for headers. 1087 */ 1088 1089 static u8 ipv6_push_rthdr0(struct sk_buff *skb, u8 proto, 1090 struct ipv6_rt_hdr *opt, 1091 struct in6_addr **addr_p, struct in6_addr *saddr) 1092 { 1093 struct rt0_hdr *phdr, *ihdr; 1094 int hops; 1095 1096 ihdr = (struct rt0_hdr *) opt; 1097 1098 phdr = skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 1099 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 1100 1101 hops = ihdr->rt_hdr.hdrlen >> 1; 1102 1103 if (hops > 1) 1104 memcpy(phdr->addr, ihdr->addr + 1, 1105 (hops - 1) * sizeof(struct in6_addr)); 1106 1107 phdr->addr[hops - 1] = **addr_p; 1108 *addr_p = ihdr->addr; 1109 1110 phdr->rt_hdr.nexthdr = proto; 1111 return NEXTHDR_ROUTING; 1112 } 1113 1114 static u8 ipv6_push_rthdr4(struct sk_buff *skb, u8 proto, 1115 struct ipv6_rt_hdr *opt, 1116 struct in6_addr **addr_p, struct in6_addr *saddr) 1117 { 1118 struct ipv6_sr_hdr *sr_phdr, *sr_ihdr; 1119 int plen, hops; 1120 1121 sr_ihdr = (struct ipv6_sr_hdr *)opt; 1122 plen = (sr_ihdr->hdrlen + 1) << 3; 1123 1124 sr_phdr = skb_push(skb, plen); 1125 memcpy(sr_phdr, sr_ihdr, sizeof(struct ipv6_sr_hdr)); 1126 1127 hops = sr_ihdr->first_segment + 1; 1128 memcpy(sr_phdr->segments + 1, sr_ihdr->segments + 1, 1129 (hops - 1) * sizeof(struct in6_addr)); 1130 1131 sr_phdr->segments[0] = **addr_p; 1132 *addr_p = &sr_ihdr->segments[sr_ihdr->segments_left]; 1133 1134 if (sr_ihdr->hdrlen > hops * 2) { 1135 int tlvs_offset, tlvs_length; 1136 1137 tlvs_offset = (1 + hops * 2) << 3; 1138 tlvs_length = (sr_ihdr->hdrlen - hops * 2) << 3; 1139 memcpy((char *)sr_phdr + tlvs_offset, 1140 (char *)sr_ihdr + tlvs_offset, tlvs_length); 1141 } 1142 1143 #ifdef CONFIG_IPV6_SEG6_HMAC 1144 if (sr_has_hmac(sr_phdr)) { 1145 struct net *net = NULL; 1146 1147 if (skb->dev) 1148 net = dev_net(skb->dev); 1149 else if (skb->sk) 1150 net = sock_net(skb->sk); 1151 1152 WARN_ON(!net); 1153 1154 if (net) 1155 seg6_push_hmac(net, saddr, sr_phdr); 1156 } 1157 #endif 1158 1159 sr_phdr->nexthdr = proto; 1160 return NEXTHDR_ROUTING; 1161 } 1162 1163 static u8 ipv6_push_rthdr(struct sk_buff *skb, u8 proto, 1164 struct ipv6_rt_hdr *opt, 1165 struct in6_addr **addr_p, struct in6_addr *saddr) 1166 { 1167 switch (opt->type) { 1168 case IPV6_SRCRT_TYPE_0: 1169 case IPV6_SRCRT_STRICT: 1170 case IPV6_SRCRT_TYPE_2: 1171 proto = ipv6_push_rthdr0(skb, proto, opt, addr_p, saddr); 1172 break; 1173 case IPV6_SRCRT_TYPE_4: 1174 proto = ipv6_push_rthdr4(skb, proto, opt, addr_p, saddr); 1175 break; 1176 default: 1177 break; 1178 } 1179 return proto; 1180 } 1181 1182 static u8 ipv6_push_exthdr(struct sk_buff *skb, u8 proto, u8 type, struct ipv6_opt_hdr *opt) 1183 { 1184 struct ipv6_opt_hdr *h = skb_push(skb, ipv6_optlen(opt)); 1185 1186 memcpy(h, opt, ipv6_optlen(opt)); 1187 h->nexthdr = proto; 1188 return type; 1189 } 1190 1191 u8 ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 1192 u8 proto, 1193 struct in6_addr **daddr, struct in6_addr *saddr) 1194 { 1195 if (opt->srcrt) { 1196 proto = ipv6_push_rthdr(skb, proto, opt->srcrt, daddr, saddr); 1197 /* 1198 * IPV6_RTHDRDSTOPTS is ignored 1199 * unless IPV6_RTHDR is set (RFC3542). 1200 */ 1201 if (opt->dst0opt) 1202 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 1203 } 1204 if (opt->hopopt) 1205 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 1206 return proto; 1207 } 1208 1209 u8 ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 proto) 1210 { 1211 if (opt->dst1opt) 1212 proto = ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 1213 return proto; 1214 } 1215 EXPORT_SYMBOL(ipv6_push_frag_opts); 1216 1217 struct ipv6_txoptions * 1218 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 1219 { 1220 struct ipv6_txoptions *opt2; 1221 1222 opt2 = sock_kmemdup(sk, opt, opt->tot_len, GFP_ATOMIC); 1223 if (opt2) { 1224 long dif = (char *)opt2 - (char *)opt; 1225 if (opt2->hopopt) 1226 *((char **)&opt2->hopopt) += dif; 1227 if (opt2->dst0opt) 1228 *((char **)&opt2->dst0opt) += dif; 1229 if (opt2->dst1opt) 1230 *((char **)&opt2->dst1opt) += dif; 1231 if (opt2->srcrt) 1232 *((char **)&opt2->srcrt) += dif; 1233 refcount_set(&opt2->refcnt, 1); 1234 } 1235 return opt2; 1236 } 1237 EXPORT_SYMBOL_GPL(ipv6_dup_options); 1238 1239 static void ipv6_renew_option(int renewtype, 1240 struct ipv6_opt_hdr **dest, 1241 struct ipv6_opt_hdr *old, 1242 struct ipv6_opt_hdr *new, 1243 int newtype, char **p) 1244 { 1245 struct ipv6_opt_hdr *src; 1246 1247 src = (renewtype == newtype ? new : old); 1248 if (!src) 1249 return; 1250 1251 memcpy(*p, src, ipv6_optlen(src)); 1252 *dest = (struct ipv6_opt_hdr *)*p; 1253 *p += CMSG_ALIGN(ipv6_optlen(*dest)); 1254 } 1255 1256 /** 1257 * ipv6_renew_options - replace a specific ext hdr with a new one. 1258 * 1259 * @sk: sock from which to allocate memory 1260 * @opt: original options 1261 * @newtype: option type to replace in @opt 1262 * @newopt: new option of type @newtype to replace (user-mem) 1263 * 1264 * Returns a new set of options which is a copy of @opt with the 1265 * option type @newtype replaced with @newopt. 1266 * 1267 * @opt may be NULL, in which case a new set of options is returned 1268 * containing just @newopt. 1269 * 1270 * @newopt may be NULL, in which case the specified option type is 1271 * not copied into the new set of options. 1272 * 1273 * The new set of options is allocated from the socket option memory 1274 * buffer of @sk. 1275 */ 1276 struct ipv6_txoptions * 1277 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 1278 int newtype, struct ipv6_opt_hdr *newopt) 1279 { 1280 int tot_len = 0; 1281 char *p; 1282 struct ipv6_txoptions *opt2; 1283 1284 if (opt) { 1285 if (newtype != IPV6_HOPOPTS && opt->hopopt) 1286 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 1287 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 1288 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 1289 if (newtype != IPV6_RTHDR && opt->srcrt) 1290 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 1291 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 1292 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 1293 } 1294 1295 if (newopt) 1296 tot_len += CMSG_ALIGN(ipv6_optlen(newopt)); 1297 1298 if (!tot_len) 1299 return NULL; 1300 1301 tot_len += sizeof(*opt2); 1302 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 1303 if (!opt2) 1304 return ERR_PTR(-ENOBUFS); 1305 1306 memset(opt2, 0, tot_len); 1307 refcount_set(&opt2->refcnt, 1); 1308 opt2->tot_len = tot_len; 1309 p = (char *)(opt2 + 1); 1310 1311 ipv6_renew_option(IPV6_HOPOPTS, &opt2->hopopt, 1312 (opt ? opt->hopopt : NULL), 1313 newopt, newtype, &p); 1314 ipv6_renew_option(IPV6_RTHDRDSTOPTS, &opt2->dst0opt, 1315 (opt ? opt->dst0opt : NULL), 1316 newopt, newtype, &p); 1317 ipv6_renew_option(IPV6_RTHDR, 1318 (struct ipv6_opt_hdr **)&opt2->srcrt, 1319 (opt ? (struct ipv6_opt_hdr *)opt->srcrt : NULL), 1320 newopt, newtype, &p); 1321 ipv6_renew_option(IPV6_DSTOPTS, &opt2->dst1opt, 1322 (opt ? opt->dst1opt : NULL), 1323 newopt, newtype, &p); 1324 1325 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 1326 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 1327 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 1328 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 1329 1330 return opt2; 1331 } 1332 1333 struct ipv6_txoptions *__ipv6_fixup_options(struct ipv6_txoptions *opt_space, 1334 struct ipv6_txoptions *opt) 1335 { 1336 /* 1337 * ignore the dest before srcrt unless srcrt is being included. 1338 * --yoshfuji 1339 */ 1340 if (opt->dst0opt && !opt->srcrt) { 1341 if (opt_space != opt) { 1342 memcpy(opt_space, opt, sizeof(*opt_space)); 1343 opt = opt_space; 1344 } 1345 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 1346 opt->dst0opt = NULL; 1347 } 1348 1349 return opt; 1350 } 1351 EXPORT_SYMBOL_GPL(__ipv6_fixup_options); 1352 1353 /** 1354 * __fl6_update_dst - update flowi destination address with info given 1355 * by srcrt option, if any. 1356 * 1357 * @fl6: flowi6 for which daddr is to be updated 1358 * @opt: struct ipv6_txoptions in which to look for srcrt opt 1359 * @orig: copy of original daddr address if modified 1360 * 1361 * Return: NULL if no srcrt or invalid srcrt type, otherwise returns orig 1362 * and initial value of fl6->daddr set in orig 1363 */ 1364 struct in6_addr *__fl6_update_dst(struct flowi6 *fl6, 1365 const struct ipv6_txoptions *opt, 1366 struct in6_addr *orig) 1367 { 1368 if (!opt->srcrt) 1369 return NULL; 1370 1371 *orig = fl6->daddr; 1372 1373 switch (opt->srcrt->type) { 1374 case IPV6_SRCRT_TYPE_0: 1375 case IPV6_SRCRT_STRICT: 1376 case IPV6_SRCRT_TYPE_2: 1377 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 1378 break; 1379 case IPV6_SRCRT_TYPE_4: 1380 { 1381 struct ipv6_sr_hdr *srh = (struct ipv6_sr_hdr *)opt->srcrt; 1382 1383 fl6->daddr = srh->segments[srh->segments_left]; 1384 break; 1385 } 1386 default: 1387 return NULL; 1388 } 1389 1390 return orig; 1391 } 1392 EXPORT_SYMBOL_GPL(__fl6_update_dst); 1393