1 /* 2 * Extension Header handling for IPv6 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * Andi Kleen <ak@muc.de> 8 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 9 * 10 * This program is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU General Public License 12 * as published by the Free Software Foundation; either version 13 * 2 of the License, or (at your option) any later version. 14 */ 15 16 /* Changes: 17 * yoshfuji : ensure not to overrun while parsing 18 * tlv options. 19 * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). 20 * YOSHIFUJI Hideaki @USAGI Register inbound extension header 21 * handlers as inet6_protocol{}. 22 */ 23 24 #include <linux/errno.h> 25 #include <linux/types.h> 26 #include <linux/socket.h> 27 #include <linux/sockios.h> 28 #include <linux/net.h> 29 #include <linux/netdevice.h> 30 #include <linux/in6.h> 31 #include <linux/icmpv6.h> 32 #include <linux/slab.h> 33 #include <linux/export.h> 34 35 #include <net/dst.h> 36 #include <net/sock.h> 37 #include <net/snmp.h> 38 39 #include <net/ipv6.h> 40 #include <net/protocol.h> 41 #include <net/transp_v6.h> 42 #include <net/rawv6.h> 43 #include <net/ndisc.h> 44 #include <net/ip6_route.h> 45 #include <net/addrconf.h> 46 #include <net/calipso.h> 47 #if IS_ENABLED(CONFIG_IPV6_MIP6) 48 #include <net/xfrm.h> 49 #endif 50 51 #include <linux/uaccess.h> 52 53 /* 54 * Parsing tlv encoded headers. 55 * 56 * Parsing function "func" returns true, if parsing succeed 57 * and false, if it failed. 58 * It MUST NOT touch skb->h. 59 */ 60 61 struct tlvtype_proc { 62 int type; 63 bool (*func)(struct sk_buff *skb, int offset); 64 }; 65 66 /********************* 67 Generic functions 68 *********************/ 69 70 /* An unknown option is detected, decide what to do */ 71 72 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff) 73 { 74 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 75 case 0: /* ignore */ 76 return true; 77 78 case 1: /* drop packet */ 79 break; 80 81 case 3: /* Send ICMP if not a multicast address and drop packet */ 82 /* Actually, it is redundant check. icmp_send 83 will recheck in any case. 84 */ 85 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 86 break; 87 case 2: /* send ICMP PARM PROB regardless and drop packet */ 88 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 89 return false; 90 } 91 92 kfree_skb(skb); 93 return false; 94 } 95 96 /* Parse tlv encoded option header (hop-by-hop or destination) */ 97 98 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb) 99 { 100 const struct tlvtype_proc *curr; 101 const unsigned char *nh = skb_network_header(skb); 102 int off = skb_network_header_len(skb); 103 int len = (skb_transport_header(skb)[1] + 1) << 3; 104 int padlen = 0; 105 106 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 107 goto bad; 108 109 off += 2; 110 len -= 2; 111 112 while (len > 0) { 113 int optlen = nh[off + 1] + 2; 114 int i; 115 116 switch (nh[off]) { 117 case IPV6_TLV_PAD1: 118 optlen = 1; 119 padlen++; 120 if (padlen > 7) 121 goto bad; 122 break; 123 124 case IPV6_TLV_PADN: 125 /* RFC 2460 states that the purpose of PadN is 126 * to align the containing header to multiples 127 * of 8. 7 is therefore the highest valid value. 128 * See also RFC 4942, Section 2.1.9.5. 129 */ 130 padlen += optlen; 131 if (padlen > 7) 132 goto bad; 133 /* RFC 4942 recommends receiving hosts to 134 * actively check PadN payload to contain 135 * only zeroes. 136 */ 137 for (i = 2; i < optlen; i++) { 138 if (nh[off + i] != 0) 139 goto bad; 140 } 141 break; 142 143 default: /* Other TLV code so scan list */ 144 if (optlen > len) 145 goto bad; 146 for (curr = procs; curr->type >= 0; curr++) { 147 if (curr->type == nh[off]) { 148 /* type specific length/alignment 149 checks will be performed in the 150 func(). */ 151 if (curr->func(skb, off) == false) 152 return false; 153 break; 154 } 155 } 156 if (curr->type < 0) { 157 if (ip6_tlvopt_unknown(skb, off) == 0) 158 return false; 159 } 160 padlen = 0; 161 break; 162 } 163 off += optlen; 164 len -= optlen; 165 } 166 167 if (len == 0) 168 return true; 169 bad: 170 kfree_skb(skb); 171 return false; 172 } 173 174 /***************************** 175 Destination options header. 176 *****************************/ 177 178 #if IS_ENABLED(CONFIG_IPV6_MIP6) 179 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 180 { 181 struct ipv6_destopt_hao *hao; 182 struct inet6_skb_parm *opt = IP6CB(skb); 183 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 184 struct in6_addr tmp_addr; 185 int ret; 186 187 if (opt->dsthao) { 188 net_dbg_ratelimited("hao duplicated\n"); 189 goto discard; 190 } 191 opt->dsthao = opt->dst1; 192 opt->dst1 = 0; 193 194 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 195 196 if (hao->length != 16) { 197 net_dbg_ratelimited("hao invalid option length = %d\n", 198 hao->length); 199 goto discard; 200 } 201 202 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 203 net_dbg_ratelimited("hao is not an unicast addr: %pI6\n", 204 &hao->addr); 205 goto discard; 206 } 207 208 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 209 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 210 if (unlikely(ret < 0)) 211 goto discard; 212 213 if (skb_cloned(skb)) { 214 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 215 goto discard; 216 217 /* update all variable using below by copied skbuff */ 218 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 219 optoff); 220 ipv6h = ipv6_hdr(skb); 221 } 222 223 if (skb->ip_summed == CHECKSUM_COMPLETE) 224 skb->ip_summed = CHECKSUM_NONE; 225 226 tmp_addr = ipv6h->saddr; 227 ipv6h->saddr = hao->addr; 228 hao->addr = tmp_addr; 229 230 if (skb->tstamp.tv64 == 0) 231 __net_timestamp(skb); 232 233 return true; 234 235 discard: 236 kfree_skb(skb); 237 return false; 238 } 239 #endif 240 241 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 242 #if IS_ENABLED(CONFIG_IPV6_MIP6) 243 { 244 .type = IPV6_TLV_HAO, 245 .func = ipv6_dest_hao, 246 }, 247 #endif 248 {-1, NULL} 249 }; 250 251 static int ipv6_destopt_rcv(struct sk_buff *skb) 252 { 253 struct inet6_skb_parm *opt = IP6CB(skb); 254 #if IS_ENABLED(CONFIG_IPV6_MIP6) 255 __u16 dstbuf; 256 #endif 257 struct dst_entry *dst = skb_dst(skb); 258 259 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 260 !pskb_may_pull(skb, (skb_transport_offset(skb) + 261 ((skb_transport_header(skb)[1] + 1) << 3)))) { 262 __IP6_INC_STATS(dev_net(dst->dev), ip6_dst_idev(dst), 263 IPSTATS_MIB_INHDRERRORS); 264 kfree_skb(skb); 265 return -1; 266 } 267 268 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 269 #if IS_ENABLED(CONFIG_IPV6_MIP6) 270 dstbuf = opt->dst1; 271 #endif 272 273 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) { 274 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 275 opt = IP6CB(skb); 276 #if IS_ENABLED(CONFIG_IPV6_MIP6) 277 opt->nhoff = dstbuf; 278 #else 279 opt->nhoff = opt->dst1; 280 #endif 281 return 1; 282 } 283 284 __IP6_INC_STATS(dev_net(dst->dev), 285 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); 286 return -1; 287 } 288 289 /******************************** 290 Routing header. 291 ********************************/ 292 293 /* called with rcu_read_lock() */ 294 static int ipv6_rthdr_rcv(struct sk_buff *skb) 295 { 296 struct inet6_skb_parm *opt = IP6CB(skb); 297 struct in6_addr *addr = NULL; 298 struct in6_addr daddr; 299 struct inet6_dev *idev; 300 int n, i; 301 struct ipv6_rt_hdr *hdr; 302 struct rt0_hdr *rthdr; 303 struct net *net = dev_net(skb->dev); 304 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 305 306 idev = __in6_dev_get(skb->dev); 307 if (idev && accept_source_route > idev->cnf.accept_source_route) 308 accept_source_route = idev->cnf.accept_source_route; 309 310 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 311 !pskb_may_pull(skb, (skb_transport_offset(skb) + 312 ((skb_transport_header(skb)[1] + 1) << 3)))) { 313 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 314 IPSTATS_MIB_INHDRERRORS); 315 kfree_skb(skb); 316 return -1; 317 } 318 319 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 320 321 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 322 skb->pkt_type != PACKET_HOST) { 323 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 324 IPSTATS_MIB_INADDRERRORS); 325 kfree_skb(skb); 326 return -1; 327 } 328 329 looped_back: 330 if (hdr->segments_left == 0) { 331 switch (hdr->type) { 332 #if IS_ENABLED(CONFIG_IPV6_MIP6) 333 case IPV6_SRCRT_TYPE_2: 334 /* Silently discard type 2 header unless it was 335 * processed by own 336 */ 337 if (!addr) { 338 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 339 IPSTATS_MIB_INADDRERRORS); 340 kfree_skb(skb); 341 return -1; 342 } 343 break; 344 #endif 345 default: 346 break; 347 } 348 349 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 350 skb->transport_header += (hdr->hdrlen + 1) << 3; 351 opt->dst0 = opt->dst1; 352 opt->dst1 = 0; 353 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 354 return 1; 355 } 356 357 switch (hdr->type) { 358 #if IS_ENABLED(CONFIG_IPV6_MIP6) 359 case IPV6_SRCRT_TYPE_2: 360 if (accept_source_route < 0) 361 goto unknown_rh; 362 /* Silently discard invalid RTH type 2 */ 363 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 364 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 365 IPSTATS_MIB_INHDRERRORS); 366 kfree_skb(skb); 367 return -1; 368 } 369 break; 370 #endif 371 default: 372 goto unknown_rh; 373 } 374 375 /* 376 * This is the routing header forwarding algorithm from 377 * RFC 2460, page 16. 378 */ 379 380 n = hdr->hdrlen >> 1; 381 382 if (hdr->segments_left > n) { 383 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 384 IPSTATS_MIB_INHDRERRORS); 385 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 386 ((&hdr->segments_left) - 387 skb_network_header(skb))); 388 return -1; 389 } 390 391 /* We are about to mangle packet header. Be careful! 392 Do not damage packets queued somewhere. 393 */ 394 if (skb_cloned(skb)) { 395 /* the copy is a forwarded packet */ 396 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 397 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 398 IPSTATS_MIB_OUTDISCARDS); 399 kfree_skb(skb); 400 return -1; 401 } 402 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 403 } 404 405 if (skb->ip_summed == CHECKSUM_COMPLETE) 406 skb->ip_summed = CHECKSUM_NONE; 407 408 i = n - --hdr->segments_left; 409 410 rthdr = (struct rt0_hdr *) hdr; 411 addr = rthdr->addr; 412 addr += i - 1; 413 414 switch (hdr->type) { 415 #if IS_ENABLED(CONFIG_IPV6_MIP6) 416 case IPV6_SRCRT_TYPE_2: 417 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 418 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 419 IPPROTO_ROUTING) < 0) { 420 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 421 IPSTATS_MIB_INADDRERRORS); 422 kfree_skb(skb); 423 return -1; 424 } 425 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 426 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 427 IPSTATS_MIB_INADDRERRORS); 428 kfree_skb(skb); 429 return -1; 430 } 431 break; 432 #endif 433 default: 434 break; 435 } 436 437 if (ipv6_addr_is_multicast(addr)) { 438 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 439 IPSTATS_MIB_INADDRERRORS); 440 kfree_skb(skb); 441 return -1; 442 } 443 444 daddr = *addr; 445 *addr = ipv6_hdr(skb)->daddr; 446 ipv6_hdr(skb)->daddr = daddr; 447 448 skb_dst_drop(skb); 449 ip6_route_input(skb); 450 if (skb_dst(skb)->error) { 451 skb_push(skb, skb->data - skb_network_header(skb)); 452 dst_input(skb); 453 return -1; 454 } 455 456 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 457 if (ipv6_hdr(skb)->hop_limit <= 1) { 458 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), 459 IPSTATS_MIB_INHDRERRORS); 460 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 461 0); 462 kfree_skb(skb); 463 return -1; 464 } 465 ipv6_hdr(skb)->hop_limit--; 466 goto looped_back; 467 } 468 469 skb_push(skb, skb->data - skb_network_header(skb)); 470 dst_input(skb); 471 return -1; 472 473 unknown_rh: 474 __IP6_INC_STATS(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); 475 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 476 (&hdr->type) - skb_network_header(skb)); 477 return -1; 478 } 479 480 static const struct inet6_protocol rthdr_protocol = { 481 .handler = ipv6_rthdr_rcv, 482 .flags = INET6_PROTO_NOPOLICY, 483 }; 484 485 static const struct inet6_protocol destopt_protocol = { 486 .handler = ipv6_destopt_rcv, 487 .flags = INET6_PROTO_NOPOLICY, 488 }; 489 490 static const struct inet6_protocol nodata_protocol = { 491 .handler = dst_discard, 492 .flags = INET6_PROTO_NOPOLICY, 493 }; 494 495 int __init ipv6_exthdrs_init(void) 496 { 497 int ret; 498 499 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 500 if (ret) 501 goto out; 502 503 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 504 if (ret) 505 goto out_rthdr; 506 507 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 508 if (ret) 509 goto out_destopt; 510 511 out: 512 return ret; 513 out_destopt: 514 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 515 out_rthdr: 516 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 517 goto out; 518 }; 519 520 void ipv6_exthdrs_exit(void) 521 { 522 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 523 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 524 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 525 } 526 527 /********************************** 528 Hop-by-hop options. 529 **********************************/ 530 531 /* 532 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 533 */ 534 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 535 { 536 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 537 } 538 539 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 540 { 541 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 542 } 543 544 /* Router Alert as of RFC 2711 */ 545 546 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 547 { 548 const unsigned char *nh = skb_network_header(skb); 549 550 if (nh[optoff + 1] == 2) { 551 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 552 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 553 return true; 554 } 555 net_dbg_ratelimited("ipv6_hop_ra: wrong RA length %d\n", 556 nh[optoff + 1]); 557 kfree_skb(skb); 558 return false; 559 } 560 561 /* Jumbo payload */ 562 563 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 564 { 565 const unsigned char *nh = skb_network_header(skb); 566 struct net *net = ipv6_skb_net(skb); 567 u32 pkt_len; 568 569 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 570 net_dbg_ratelimited("ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 571 nh[optoff+1]); 572 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 573 IPSTATS_MIB_INHDRERRORS); 574 goto drop; 575 } 576 577 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 578 if (pkt_len <= IPV6_MAXPLEN) { 579 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 580 IPSTATS_MIB_INHDRERRORS); 581 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 582 return false; 583 } 584 if (ipv6_hdr(skb)->payload_len) { 585 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 586 IPSTATS_MIB_INHDRERRORS); 587 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 588 return false; 589 } 590 591 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 592 __IP6_INC_STATS(net, ipv6_skb_idev(skb), 593 IPSTATS_MIB_INTRUNCATEDPKTS); 594 goto drop; 595 } 596 597 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 598 goto drop; 599 600 return true; 601 602 drop: 603 kfree_skb(skb); 604 return false; 605 } 606 607 /* CALIPSO RFC 5570 */ 608 609 static bool ipv6_hop_calipso(struct sk_buff *skb, int optoff) 610 { 611 const unsigned char *nh = skb_network_header(skb); 612 613 if (nh[optoff + 1] < 8) 614 goto drop; 615 616 if (nh[optoff + 6] * 4 + 8 > nh[optoff + 1]) 617 goto drop; 618 619 if (!calipso_validate(skb, nh + optoff)) 620 goto drop; 621 622 return true; 623 624 drop: 625 kfree_skb(skb); 626 return false; 627 } 628 629 static const struct tlvtype_proc tlvprochopopt_lst[] = { 630 { 631 .type = IPV6_TLV_ROUTERALERT, 632 .func = ipv6_hop_ra, 633 }, 634 { 635 .type = IPV6_TLV_JUMBO, 636 .func = ipv6_hop_jumbo, 637 }, 638 { 639 .type = IPV6_TLV_CALIPSO, 640 .func = ipv6_hop_calipso, 641 }, 642 { -1, } 643 }; 644 645 int ipv6_parse_hopopts(struct sk_buff *skb) 646 { 647 struct inet6_skb_parm *opt = IP6CB(skb); 648 649 /* 650 * skb_network_header(skb) is equal to skb->data, and 651 * skb_network_header_len(skb) is always equal to 652 * sizeof(struct ipv6hdr) by definition of 653 * hop-by-hop options. 654 */ 655 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 656 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 657 ((skb_transport_header(skb)[1] + 1) << 3)))) { 658 kfree_skb(skb); 659 return -1; 660 } 661 662 opt->flags |= IP6SKB_HOPBYHOP; 663 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) { 664 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 665 opt = IP6CB(skb); 666 opt->nhoff = sizeof(struct ipv6hdr); 667 return 1; 668 } 669 return -1; 670 } 671 672 /* 673 * Creating outbound headers. 674 * 675 * "build" functions work when skb is filled from head to tail (datagram) 676 * "push" functions work when headers are added from tail to head (tcp) 677 * 678 * In both cases we assume, that caller reserved enough room 679 * for headers. 680 */ 681 682 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 683 struct ipv6_rt_hdr *opt, 684 struct in6_addr **addr_p) 685 { 686 struct rt0_hdr *phdr, *ihdr; 687 int hops; 688 689 ihdr = (struct rt0_hdr *) opt; 690 691 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 692 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 693 694 hops = ihdr->rt_hdr.hdrlen >> 1; 695 696 if (hops > 1) 697 memcpy(phdr->addr, ihdr->addr + 1, 698 (hops - 1) * sizeof(struct in6_addr)); 699 700 phdr->addr[hops - 1] = **addr_p; 701 *addr_p = ihdr->addr; 702 703 phdr->rt_hdr.nexthdr = *proto; 704 *proto = NEXTHDR_ROUTING; 705 } 706 707 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 708 { 709 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt)); 710 711 memcpy(h, opt, ipv6_optlen(opt)); 712 h->nexthdr = *proto; 713 *proto = type; 714 } 715 716 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 717 u8 *proto, 718 struct in6_addr **daddr) 719 { 720 if (opt->srcrt) { 721 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr); 722 /* 723 * IPV6_RTHDRDSTOPTS is ignored 724 * unless IPV6_RTHDR is set (RFC3542). 725 */ 726 if (opt->dst0opt) 727 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 728 } 729 if (opt->hopopt) 730 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 731 } 732 EXPORT_SYMBOL(ipv6_push_nfrag_opts); 733 734 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 735 { 736 if (opt->dst1opt) 737 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 738 } 739 740 struct ipv6_txoptions * 741 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 742 { 743 struct ipv6_txoptions *opt2; 744 745 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 746 if (opt2) { 747 long dif = (char *)opt2 - (char *)opt; 748 memcpy(opt2, opt, opt->tot_len); 749 if (opt2->hopopt) 750 *((char **)&opt2->hopopt) += dif; 751 if (opt2->dst0opt) 752 *((char **)&opt2->dst0opt) += dif; 753 if (opt2->dst1opt) 754 *((char **)&opt2->dst1opt) += dif; 755 if (opt2->srcrt) 756 *((char **)&opt2->srcrt) += dif; 757 atomic_set(&opt2->refcnt, 1); 758 } 759 return opt2; 760 } 761 EXPORT_SYMBOL_GPL(ipv6_dup_options); 762 763 static int ipv6_renew_option(void *ohdr, 764 struct ipv6_opt_hdr __user *newopt, int newoptlen, 765 int inherit, 766 struct ipv6_opt_hdr **hdr, 767 char **p) 768 { 769 if (inherit) { 770 if (ohdr) { 771 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); 772 *hdr = (struct ipv6_opt_hdr *)*p; 773 *p += CMSG_ALIGN(ipv6_optlen(*hdr)); 774 } 775 } else { 776 if (newopt) { 777 if (copy_from_user(*p, newopt, newoptlen)) 778 return -EFAULT; 779 *hdr = (struct ipv6_opt_hdr *)*p; 780 if (ipv6_optlen(*hdr) > newoptlen) 781 return -EINVAL; 782 *p += CMSG_ALIGN(newoptlen); 783 } 784 } 785 return 0; 786 } 787 788 /** 789 * ipv6_renew_options - replace a specific ext hdr with a new one. 790 * 791 * @sk: sock from which to allocate memory 792 * @opt: original options 793 * @newtype: option type to replace in @opt 794 * @newopt: new option of type @newtype to replace (user-mem) 795 * @newoptlen: length of @newopt 796 * 797 * Returns a new set of options which is a copy of @opt with the 798 * option type @newtype replaced with @newopt. 799 * 800 * @opt may be NULL, in which case a new set of options is returned 801 * containing just @newopt. 802 * 803 * @newopt may be NULL, in which case the specified option type is 804 * not copied into the new set of options. 805 * 806 * The new set of options is allocated from the socket option memory 807 * buffer of @sk. 808 */ 809 struct ipv6_txoptions * 810 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 811 int newtype, 812 struct ipv6_opt_hdr __user *newopt, int newoptlen) 813 { 814 int tot_len = 0; 815 char *p; 816 struct ipv6_txoptions *opt2; 817 int err; 818 819 if (opt) { 820 if (newtype != IPV6_HOPOPTS && opt->hopopt) 821 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 822 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 823 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 824 if (newtype != IPV6_RTHDR && opt->srcrt) 825 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 826 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 827 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 828 } 829 830 if (newopt && newoptlen) 831 tot_len += CMSG_ALIGN(newoptlen); 832 833 if (!tot_len) 834 return NULL; 835 836 tot_len += sizeof(*opt2); 837 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 838 if (!opt2) 839 return ERR_PTR(-ENOBUFS); 840 841 memset(opt2, 0, tot_len); 842 atomic_set(&opt2->refcnt, 1); 843 opt2->tot_len = tot_len; 844 p = (char *)(opt2 + 1); 845 846 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, 847 newtype != IPV6_HOPOPTS, 848 &opt2->hopopt, &p); 849 if (err) 850 goto out; 851 852 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, 853 newtype != IPV6_RTHDRDSTOPTS, 854 &opt2->dst0opt, &p); 855 if (err) 856 goto out; 857 858 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, 859 newtype != IPV6_RTHDR, 860 (struct ipv6_opt_hdr **)&opt2->srcrt, &p); 861 if (err) 862 goto out; 863 864 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, 865 newtype != IPV6_DSTOPTS, 866 &opt2->dst1opt, &p); 867 if (err) 868 goto out; 869 870 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 871 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 872 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 873 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 874 875 return opt2; 876 out: 877 sock_kfree_s(sk, opt2, opt2->tot_len); 878 return ERR_PTR(err); 879 } 880 881 /** 882 * ipv6_renew_options_kern - replace a specific ext hdr with a new one. 883 * 884 * @sk: sock from which to allocate memory 885 * @opt: original options 886 * @newtype: option type to replace in @opt 887 * @newopt: new option of type @newtype to replace (kernel-mem) 888 * @newoptlen: length of @newopt 889 * 890 * See ipv6_renew_options(). The difference is that @newopt is 891 * kernel memory, rather than user memory. 892 */ 893 struct ipv6_txoptions * 894 ipv6_renew_options_kern(struct sock *sk, struct ipv6_txoptions *opt, 895 int newtype, struct ipv6_opt_hdr *newopt, 896 int newoptlen) 897 { 898 struct ipv6_txoptions *ret_val; 899 const mm_segment_t old_fs = get_fs(); 900 901 set_fs(KERNEL_DS); 902 ret_val = ipv6_renew_options(sk, opt, newtype, 903 (struct ipv6_opt_hdr __user *)newopt, 904 newoptlen); 905 set_fs(old_fs); 906 return ret_val; 907 } 908 909 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 910 struct ipv6_txoptions *opt) 911 { 912 /* 913 * ignore the dest before srcrt unless srcrt is being included. 914 * --yoshfuji 915 */ 916 if (opt && opt->dst0opt && !opt->srcrt) { 917 if (opt_space != opt) { 918 memcpy(opt_space, opt, sizeof(*opt_space)); 919 opt = opt_space; 920 } 921 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 922 opt->dst0opt = NULL; 923 } 924 925 return opt; 926 } 927 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 928 929 /** 930 * fl6_update_dst - update flowi destination address with info given 931 * by srcrt option, if any. 932 * 933 * @fl6: flowi6 for which daddr is to be updated 934 * @opt: struct ipv6_txoptions in which to look for srcrt opt 935 * @orig: copy of original daddr address if modified 936 * 937 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 938 * and initial value of fl6->daddr set in orig 939 */ 940 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 941 const struct ipv6_txoptions *opt, 942 struct in6_addr *orig) 943 { 944 if (!opt || !opt->srcrt) 945 return NULL; 946 947 *orig = fl6->daddr; 948 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 949 return orig; 950 } 951 EXPORT_SYMBOL_GPL(fl6_update_dst); 952