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 #if IS_ENABLED(CONFIG_IPV6_MIP6) 47 #include <net/xfrm.h> 48 #endif 49 50 #include <asm/uaccess.h> 51 52 /* 53 * Parsing tlv encoded headers. 54 * 55 * Parsing function "func" returns true, if parsing succeed 56 * and false, if it failed. 57 * It MUST NOT touch skb->h. 58 */ 59 60 struct tlvtype_proc { 61 int type; 62 bool (*func)(struct sk_buff *skb, int offset); 63 }; 64 65 /********************* 66 Generic functions 67 *********************/ 68 69 /* An unknown option is detected, decide what to do */ 70 71 static bool ip6_tlvopt_unknown(struct sk_buff *skb, int optoff) 72 { 73 switch ((skb_network_header(skb)[optoff] & 0xC0) >> 6) { 74 case 0: /* ignore */ 75 return true; 76 77 case 1: /* drop packet */ 78 break; 79 80 case 3: /* Send ICMP if not a multicast address and drop packet */ 81 /* Actually, it is redundant check. icmp_send 82 will recheck in any case. 83 */ 84 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr)) 85 break; 86 case 2: /* send ICMP PARM PROB regardless and drop packet */ 87 icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); 88 return false; 89 } 90 91 kfree_skb(skb); 92 return false; 93 } 94 95 /* Parse tlv encoded option header (hop-by-hop or destination) */ 96 97 static bool ip6_parse_tlv(const struct tlvtype_proc *procs, struct sk_buff *skb) 98 { 99 const struct tlvtype_proc *curr; 100 const unsigned char *nh = skb_network_header(skb); 101 int off = skb_network_header_len(skb); 102 int len = (skb_transport_header(skb)[1] + 1) << 3; 103 int padlen = 0; 104 105 if (skb_transport_offset(skb) + len > skb_headlen(skb)) 106 goto bad; 107 108 off += 2; 109 len -= 2; 110 111 while (len > 0) { 112 int optlen = nh[off + 1] + 2; 113 int i; 114 115 switch (nh[off]) { 116 case IPV6_TLV_PAD1: 117 optlen = 1; 118 padlen++; 119 if (padlen > 7) 120 goto bad; 121 break; 122 123 case IPV6_TLV_PADN: 124 /* RFC 2460 states that the purpose of PadN is 125 * to align the containing header to multiples 126 * of 8. 7 is therefore the highest valid value. 127 * See also RFC 4942, Section 2.1.9.5. 128 */ 129 padlen += optlen; 130 if (padlen > 7) 131 goto bad; 132 /* RFC 4942 recommends receiving hosts to 133 * actively check PadN payload to contain 134 * only zeroes. 135 */ 136 for (i = 2; i < optlen; i++) { 137 if (nh[off + i] != 0) 138 goto bad; 139 } 140 break; 141 142 default: /* Other TLV code so scan list */ 143 if (optlen > len) 144 goto bad; 145 for (curr=procs; curr->type >= 0; curr++) { 146 if (curr->type == nh[off]) { 147 /* type specific length/alignment 148 checks will be performed in the 149 func(). */ 150 if (curr->func(skb, off) == false) 151 return false; 152 break; 153 } 154 } 155 if (curr->type < 0) { 156 if (ip6_tlvopt_unknown(skb, off) == 0) 157 return false; 158 } 159 padlen = 0; 160 break; 161 } 162 off += optlen; 163 len -= optlen; 164 } 165 /* This case will not be caught by above check since its padding 166 * length is smaller than 7: 167 * 1 byte NH + 1 byte Length + 6 bytes Padding 168 */ 169 if ((padlen == 6) && ((off - skb_network_header_len(skb)) == 8)) 170 goto bad; 171 172 if (len == 0) 173 return true; 174 bad: 175 kfree_skb(skb); 176 return false; 177 } 178 179 /***************************** 180 Destination options header. 181 *****************************/ 182 183 #if IS_ENABLED(CONFIG_IPV6_MIP6) 184 static bool ipv6_dest_hao(struct sk_buff *skb, int optoff) 185 { 186 struct ipv6_destopt_hao *hao; 187 struct inet6_skb_parm *opt = IP6CB(skb); 188 struct ipv6hdr *ipv6h = ipv6_hdr(skb); 189 struct in6_addr tmp_addr; 190 int ret; 191 192 if (opt->dsthao) { 193 LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n"); 194 goto discard; 195 } 196 opt->dsthao = opt->dst1; 197 opt->dst1 = 0; 198 199 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + optoff); 200 201 if (hao->length != 16) { 202 LIMIT_NETDEBUG( 203 KERN_DEBUG "hao invalid option length = %d\n", hao->length); 204 goto discard; 205 } 206 207 if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { 208 LIMIT_NETDEBUG( 209 KERN_DEBUG "hao is not an unicast addr: %pI6\n", &hao->addr); 210 goto discard; 211 } 212 213 ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, 214 (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); 215 if (unlikely(ret < 0)) 216 goto discard; 217 218 if (skb_cloned(skb)) { 219 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) 220 goto discard; 221 222 /* update all variable using below by copied skbuff */ 223 hao = (struct ipv6_destopt_hao *)(skb_network_header(skb) + 224 optoff); 225 ipv6h = ipv6_hdr(skb); 226 } 227 228 if (skb->ip_summed == CHECKSUM_COMPLETE) 229 skb->ip_summed = CHECKSUM_NONE; 230 231 tmp_addr = ipv6h->saddr; 232 ipv6h->saddr = hao->addr; 233 hao->addr = tmp_addr; 234 235 if (skb->tstamp.tv64 == 0) 236 __net_timestamp(skb); 237 238 return true; 239 240 discard: 241 kfree_skb(skb); 242 return false; 243 } 244 #endif 245 246 static const struct tlvtype_proc tlvprocdestopt_lst[] = { 247 #if IS_ENABLED(CONFIG_IPV6_MIP6) 248 { 249 .type = IPV6_TLV_HAO, 250 .func = ipv6_dest_hao, 251 }, 252 #endif 253 {-1, NULL} 254 }; 255 256 static int ipv6_destopt_rcv(struct sk_buff *skb) 257 { 258 struct inet6_skb_parm *opt = IP6CB(skb); 259 #if IS_ENABLED(CONFIG_IPV6_MIP6) 260 __u16 dstbuf; 261 #endif 262 struct dst_entry *dst = skb_dst(skb); 263 264 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 265 !pskb_may_pull(skb, (skb_transport_offset(skb) + 266 ((skb_transport_header(skb)[1] + 1) << 3)))) { 267 IP6_INC_STATS_BH(dev_net(dst->dev), ip6_dst_idev(dst), 268 IPSTATS_MIB_INHDRERRORS); 269 kfree_skb(skb); 270 return -1; 271 } 272 273 opt->lastopt = opt->dst1 = skb_network_header_len(skb); 274 #if IS_ENABLED(CONFIG_IPV6_MIP6) 275 dstbuf = opt->dst1; 276 #endif 277 278 if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) { 279 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 280 opt = IP6CB(skb); 281 #if IS_ENABLED(CONFIG_IPV6_MIP6) 282 opt->nhoff = dstbuf; 283 #else 284 opt->nhoff = opt->dst1; 285 #endif 286 return 1; 287 } 288 289 IP6_INC_STATS_BH(dev_net(dst->dev), 290 ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); 291 return -1; 292 } 293 294 /******************************** 295 Routing header. 296 ********************************/ 297 298 /* called with rcu_read_lock() */ 299 static int ipv6_rthdr_rcv(struct sk_buff *skb) 300 { 301 struct inet6_skb_parm *opt = IP6CB(skb); 302 struct in6_addr *addr = NULL; 303 struct in6_addr daddr; 304 struct inet6_dev *idev; 305 int n, i; 306 struct ipv6_rt_hdr *hdr; 307 struct rt0_hdr *rthdr; 308 struct net *net = dev_net(skb->dev); 309 int accept_source_route = net->ipv6.devconf_all->accept_source_route; 310 311 idev = __in6_dev_get(skb->dev); 312 if (idev && accept_source_route > idev->cnf.accept_source_route) 313 accept_source_route = idev->cnf.accept_source_route; 314 315 if (!pskb_may_pull(skb, skb_transport_offset(skb) + 8) || 316 !pskb_may_pull(skb, (skb_transport_offset(skb) + 317 ((skb_transport_header(skb)[1] + 1) << 3)))) { 318 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 319 IPSTATS_MIB_INHDRERRORS); 320 kfree_skb(skb); 321 return -1; 322 } 323 324 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 325 326 if (ipv6_addr_is_multicast(&ipv6_hdr(skb)->daddr) || 327 skb->pkt_type != PACKET_HOST) { 328 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 329 IPSTATS_MIB_INADDRERRORS); 330 kfree_skb(skb); 331 return -1; 332 } 333 334 looped_back: 335 if (hdr->segments_left == 0) { 336 switch (hdr->type) { 337 #if IS_ENABLED(CONFIG_IPV6_MIP6) 338 case IPV6_SRCRT_TYPE_2: 339 /* Silently discard type 2 header unless it was 340 * processed by own 341 */ 342 if (!addr) { 343 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 344 IPSTATS_MIB_INADDRERRORS); 345 kfree_skb(skb); 346 return -1; 347 } 348 break; 349 #endif 350 default: 351 break; 352 } 353 354 opt->lastopt = opt->srcrt = skb_network_header_len(skb); 355 skb->transport_header += (hdr->hdrlen + 1) << 3; 356 opt->dst0 = opt->dst1; 357 opt->dst1 = 0; 358 opt->nhoff = (&hdr->nexthdr) - skb_network_header(skb); 359 return 1; 360 } 361 362 switch (hdr->type) { 363 #if IS_ENABLED(CONFIG_IPV6_MIP6) 364 case IPV6_SRCRT_TYPE_2: 365 if (accept_source_route < 0) 366 goto unknown_rh; 367 /* Silently discard invalid RTH type 2 */ 368 if (hdr->hdrlen != 2 || hdr->segments_left != 1) { 369 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 370 IPSTATS_MIB_INHDRERRORS); 371 kfree_skb(skb); 372 return -1; 373 } 374 break; 375 #endif 376 default: 377 goto unknown_rh; 378 } 379 380 /* 381 * This is the routing header forwarding algorithm from 382 * RFC 2460, page 16. 383 */ 384 385 n = hdr->hdrlen >> 1; 386 387 if (hdr->segments_left > n) { 388 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 389 IPSTATS_MIB_INHDRERRORS); 390 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 391 ((&hdr->segments_left) - 392 skb_network_header(skb))); 393 return -1; 394 } 395 396 /* We are about to mangle packet header. Be careful! 397 Do not damage packets queued somewhere. 398 */ 399 if (skb_cloned(skb)) { 400 /* the copy is a forwarded packet */ 401 if (pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) { 402 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 403 IPSTATS_MIB_OUTDISCARDS); 404 kfree_skb(skb); 405 return -1; 406 } 407 hdr = (struct ipv6_rt_hdr *)skb_transport_header(skb); 408 } 409 410 if (skb->ip_summed == CHECKSUM_COMPLETE) 411 skb->ip_summed = CHECKSUM_NONE; 412 413 i = n - --hdr->segments_left; 414 415 rthdr = (struct rt0_hdr *) hdr; 416 addr = rthdr->addr; 417 addr += i - 1; 418 419 switch (hdr->type) { 420 #if IS_ENABLED(CONFIG_IPV6_MIP6) 421 case IPV6_SRCRT_TYPE_2: 422 if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, 423 (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 424 IPPROTO_ROUTING) < 0) { 425 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 426 IPSTATS_MIB_INADDRERRORS); 427 kfree_skb(skb); 428 return -1; 429 } 430 if (!ipv6_chk_home_addr(dev_net(skb_dst(skb)->dev), addr)) { 431 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 432 IPSTATS_MIB_INADDRERRORS); 433 kfree_skb(skb); 434 return -1; 435 } 436 break; 437 #endif 438 default: 439 break; 440 } 441 442 if (ipv6_addr_is_multicast(addr)) { 443 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 444 IPSTATS_MIB_INADDRERRORS); 445 kfree_skb(skb); 446 return -1; 447 } 448 449 daddr = *addr; 450 *addr = ipv6_hdr(skb)->daddr; 451 ipv6_hdr(skb)->daddr = daddr; 452 453 skb_dst_drop(skb); 454 ip6_route_input(skb); 455 if (skb_dst(skb)->error) { 456 skb_push(skb, skb->data - skb_network_header(skb)); 457 dst_input(skb); 458 return -1; 459 } 460 461 if (skb_dst(skb)->dev->flags&IFF_LOOPBACK) { 462 if (ipv6_hdr(skb)->hop_limit <= 1) { 463 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), 464 IPSTATS_MIB_INHDRERRORS); 465 icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 466 0); 467 kfree_skb(skb); 468 return -1; 469 } 470 ipv6_hdr(skb)->hop_limit--; 471 goto looped_back; 472 } 473 474 skb_push(skb, skb->data - skb_network_header(skb)); 475 dst_input(skb); 476 return -1; 477 478 unknown_rh: 479 IP6_INC_STATS_BH(net, ip6_dst_idev(skb_dst(skb)), IPSTATS_MIB_INHDRERRORS); 480 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, 481 (&hdr->type) - skb_network_header(skb)); 482 return -1; 483 } 484 485 static const struct inet6_protocol rthdr_protocol = { 486 .handler = ipv6_rthdr_rcv, 487 .flags = INET6_PROTO_NOPOLICY, 488 }; 489 490 static const struct inet6_protocol destopt_protocol = { 491 .handler = ipv6_destopt_rcv, 492 .flags = INET6_PROTO_NOPOLICY, 493 }; 494 495 static const struct inet6_protocol nodata_protocol = { 496 .handler = dst_discard, 497 .flags = INET6_PROTO_NOPOLICY, 498 }; 499 500 int __init ipv6_exthdrs_init(void) 501 { 502 int ret; 503 504 ret = inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING); 505 if (ret) 506 goto out; 507 508 ret = inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 509 if (ret) 510 goto out_rthdr; 511 512 ret = inet6_add_protocol(&nodata_protocol, IPPROTO_NONE); 513 if (ret) 514 goto out_destopt; 515 516 out: 517 return ret; 518 out_destopt: 519 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 520 out_rthdr: 521 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 522 goto out; 523 }; 524 525 void ipv6_exthdrs_exit(void) 526 { 527 inet6_del_protocol(&nodata_protocol, IPPROTO_NONE); 528 inet6_del_protocol(&destopt_protocol, IPPROTO_DSTOPTS); 529 inet6_del_protocol(&rthdr_protocol, IPPROTO_ROUTING); 530 } 531 532 /********************************** 533 Hop-by-hop options. 534 **********************************/ 535 536 /* 537 * Note: we cannot rely on skb_dst(skb) before we assign it in ip6_route_input(). 538 */ 539 static inline struct inet6_dev *ipv6_skb_idev(struct sk_buff *skb) 540 { 541 return skb_dst(skb) ? ip6_dst_idev(skb_dst(skb)) : __in6_dev_get(skb->dev); 542 } 543 544 static inline struct net *ipv6_skb_net(struct sk_buff *skb) 545 { 546 return skb_dst(skb) ? dev_net(skb_dst(skb)->dev) : dev_net(skb->dev); 547 } 548 549 /* Router Alert as of RFC 2711 */ 550 551 static bool ipv6_hop_ra(struct sk_buff *skb, int optoff) 552 { 553 const unsigned char *nh = skb_network_header(skb); 554 555 if (nh[optoff + 1] == 2) { 556 IP6CB(skb)->flags |= IP6SKB_ROUTERALERT; 557 memcpy(&IP6CB(skb)->ra, nh + optoff + 2, sizeof(IP6CB(skb)->ra)); 558 return true; 559 } 560 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n", 561 nh[optoff + 1]); 562 kfree_skb(skb); 563 return false; 564 } 565 566 /* Jumbo payload */ 567 568 static bool ipv6_hop_jumbo(struct sk_buff *skb, int optoff) 569 { 570 const unsigned char *nh = skb_network_header(skb); 571 struct net *net = ipv6_skb_net(skb); 572 u32 pkt_len; 573 574 if (nh[optoff + 1] != 4 || (optoff & 3) != 2) { 575 LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", 576 nh[optoff+1]); 577 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb), 578 IPSTATS_MIB_INHDRERRORS); 579 goto drop; 580 } 581 582 pkt_len = ntohl(*(__be32 *)(nh + optoff + 2)); 583 if (pkt_len <= IPV6_MAXPLEN) { 584 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb), 585 IPSTATS_MIB_INHDRERRORS); 586 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); 587 return false; 588 } 589 if (ipv6_hdr(skb)->payload_len) { 590 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb), 591 IPSTATS_MIB_INHDRERRORS); 592 icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); 593 return false; 594 } 595 596 if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { 597 IP6_INC_STATS_BH(net, ipv6_skb_idev(skb), 598 IPSTATS_MIB_INTRUNCATEDPKTS); 599 goto drop; 600 } 601 602 if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) 603 goto drop; 604 605 return true; 606 607 drop: 608 kfree_skb(skb); 609 return false; 610 } 611 612 static const struct tlvtype_proc tlvprochopopt_lst[] = { 613 { 614 .type = IPV6_TLV_ROUTERALERT, 615 .func = ipv6_hop_ra, 616 }, 617 { 618 .type = IPV6_TLV_JUMBO, 619 .func = ipv6_hop_jumbo, 620 }, 621 { -1, } 622 }; 623 624 int ipv6_parse_hopopts(struct sk_buff *skb) 625 { 626 struct inet6_skb_parm *opt = IP6CB(skb); 627 628 /* 629 * skb_network_header(skb) is equal to skb->data, and 630 * skb_network_header_len(skb) is always equal to 631 * sizeof(struct ipv6hdr) by definition of 632 * hop-by-hop options. 633 */ 634 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || 635 !pskb_may_pull(skb, (sizeof(struct ipv6hdr) + 636 ((skb_transport_header(skb)[1] + 1) << 3)))) { 637 kfree_skb(skb); 638 return -1; 639 } 640 641 opt->hop = sizeof(struct ipv6hdr); 642 if (ip6_parse_tlv(tlvprochopopt_lst, skb)) { 643 skb->transport_header += (skb_transport_header(skb)[1] + 1) << 3; 644 opt = IP6CB(skb); 645 opt->nhoff = sizeof(struct ipv6hdr); 646 return 1; 647 } 648 return -1; 649 } 650 651 /* 652 * Creating outbound headers. 653 * 654 * "build" functions work when skb is filled from head to tail (datagram) 655 * "push" functions work when headers are added from tail to head (tcp) 656 * 657 * In both cases we assume, that caller reserved enough room 658 * for headers. 659 */ 660 661 static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, 662 struct ipv6_rt_hdr *opt, 663 struct in6_addr **addr_p) 664 { 665 struct rt0_hdr *phdr, *ihdr; 666 int hops; 667 668 ihdr = (struct rt0_hdr *) opt; 669 670 phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); 671 memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); 672 673 hops = ihdr->rt_hdr.hdrlen >> 1; 674 675 if (hops > 1) 676 memcpy(phdr->addr, ihdr->addr + 1, 677 (hops - 1) * sizeof(struct in6_addr)); 678 679 phdr->addr[hops - 1] = **addr_p; 680 *addr_p = ihdr->addr; 681 682 phdr->rt_hdr.nexthdr = *proto; 683 *proto = NEXTHDR_ROUTING; 684 } 685 686 static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) 687 { 688 struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt)); 689 690 memcpy(h, opt, ipv6_optlen(opt)); 691 h->nexthdr = *proto; 692 *proto = type; 693 } 694 695 void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, 696 u8 *proto, 697 struct in6_addr **daddr) 698 { 699 if (opt->srcrt) { 700 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr); 701 /* 702 * IPV6_RTHDRDSTOPTS is ignored 703 * unless IPV6_RTHDR is set (RFC3542). 704 */ 705 if (opt->dst0opt) 706 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); 707 } 708 if (opt->hopopt) 709 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); 710 } 711 EXPORT_SYMBOL(ipv6_push_nfrag_opts); 712 713 void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) 714 { 715 if (opt->dst1opt) 716 ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); 717 } 718 719 struct ipv6_txoptions * 720 ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) 721 { 722 struct ipv6_txoptions *opt2; 723 724 opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); 725 if (opt2) { 726 long dif = (char *)opt2 - (char *)opt; 727 memcpy(opt2, opt, opt->tot_len); 728 if (opt2->hopopt) 729 *((char **)&opt2->hopopt) += dif; 730 if (opt2->dst0opt) 731 *((char **)&opt2->dst0opt) += dif; 732 if (opt2->dst1opt) 733 *((char **)&opt2->dst1opt) += dif; 734 if (opt2->srcrt) 735 *((char **)&opt2->srcrt) += dif; 736 } 737 return opt2; 738 } 739 EXPORT_SYMBOL_GPL(ipv6_dup_options); 740 741 static int ipv6_renew_option(void *ohdr, 742 struct ipv6_opt_hdr __user *newopt, int newoptlen, 743 int inherit, 744 struct ipv6_opt_hdr **hdr, 745 char **p) 746 { 747 if (inherit) { 748 if (ohdr) { 749 memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); 750 *hdr = (struct ipv6_opt_hdr *)*p; 751 *p += CMSG_ALIGN(ipv6_optlen(*hdr)); 752 } 753 } else { 754 if (newopt) { 755 if (copy_from_user(*p, newopt, newoptlen)) 756 return -EFAULT; 757 *hdr = (struct ipv6_opt_hdr *)*p; 758 if (ipv6_optlen(*hdr) > newoptlen) 759 return -EINVAL; 760 *p += CMSG_ALIGN(newoptlen); 761 } 762 } 763 return 0; 764 } 765 766 struct ipv6_txoptions * 767 ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, 768 int newtype, 769 struct ipv6_opt_hdr __user *newopt, int newoptlen) 770 { 771 int tot_len = 0; 772 char *p; 773 struct ipv6_txoptions *opt2; 774 int err; 775 776 if (opt) { 777 if (newtype != IPV6_HOPOPTS && opt->hopopt) 778 tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); 779 if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) 780 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); 781 if (newtype != IPV6_RTHDR && opt->srcrt) 782 tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); 783 if (newtype != IPV6_DSTOPTS && opt->dst1opt) 784 tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); 785 } 786 787 if (newopt && newoptlen) 788 tot_len += CMSG_ALIGN(newoptlen); 789 790 if (!tot_len) 791 return NULL; 792 793 tot_len += sizeof(*opt2); 794 opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); 795 if (!opt2) 796 return ERR_PTR(-ENOBUFS); 797 798 memset(opt2, 0, tot_len); 799 800 opt2->tot_len = tot_len; 801 p = (char *)(opt2 + 1); 802 803 err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, 804 newtype != IPV6_HOPOPTS, 805 &opt2->hopopt, &p); 806 if (err) 807 goto out; 808 809 err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, 810 newtype != IPV6_RTHDRDSTOPTS, 811 &opt2->dst0opt, &p); 812 if (err) 813 goto out; 814 815 err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, 816 newtype != IPV6_RTHDR, 817 (struct ipv6_opt_hdr **)&opt2->srcrt, &p); 818 if (err) 819 goto out; 820 821 err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, 822 newtype != IPV6_DSTOPTS, 823 &opt2->dst1opt, &p); 824 if (err) 825 goto out; 826 827 opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + 828 (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + 829 (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); 830 opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); 831 832 return opt2; 833 out: 834 sock_kfree_s(sk, opt2, opt2->tot_len); 835 return ERR_PTR(err); 836 } 837 838 struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, 839 struct ipv6_txoptions *opt) 840 { 841 /* 842 * ignore the dest before srcrt unless srcrt is being included. 843 * --yoshfuji 844 */ 845 if (opt && opt->dst0opt && !opt->srcrt) { 846 if (opt_space != opt) { 847 memcpy(opt_space, opt, sizeof(*opt_space)); 848 opt = opt_space; 849 } 850 opt->opt_nflen -= ipv6_optlen(opt->dst0opt); 851 opt->dst0opt = NULL; 852 } 853 854 return opt; 855 } 856 EXPORT_SYMBOL_GPL(ipv6_fixup_options); 857 858 /** 859 * fl6_update_dst - update flowi destination address with info given 860 * by srcrt option, if any. 861 * 862 * @fl6: flowi6 for which daddr is to be updated 863 * @opt: struct ipv6_txoptions in which to look for srcrt opt 864 * @orig: copy of original daddr address if modified 865 * 866 * Returns NULL if no txoptions or no srcrt, otherwise returns orig 867 * and initial value of fl6->daddr set in orig 868 */ 869 struct in6_addr *fl6_update_dst(struct flowi6 *fl6, 870 const struct ipv6_txoptions *opt, 871 struct in6_addr *orig) 872 { 873 if (!opt || !opt->srcrt) 874 return NULL; 875 876 *orig = fl6->daddr; 877 fl6->daddr = *((struct rt0_hdr *)opt->srcrt)->addr; 878 return orig; 879 } 880 EXPORT_SYMBOL_GPL(fl6_update_dst); 881