| 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 | * $Id: exthdrs.c,v 1.13 2001/06/19 15:58:56 davem Exp $ |
| 11 | * |
| 12 | * This program is free software; you can redistribute it and/or |
| 13 | * modify it under the terms of the GNU General Public License |
| 14 | * as published by the Free Software Foundation; either version |
| 15 | * 2 of the License, or (at your option) any later version. |
| 16 | */ |
| 17 | |
| 18 | /* Changes: |
| 19 | * yoshfuji : ensure not to overrun while parsing |
| 20 | * tlv options. |
| 21 | * Mitsuru KANDA @USAGI and: Remove ipv6_parse_exthdrs(). |
| 22 | * YOSHIFUJI Hideaki @USAGI Register inbound extension header |
| 23 | * handlers as inet6_protocol{}. |
| 24 | */ |
| 25 | |
| 26 | #include <linux/errno.h> |
| 27 | #include <linux/types.h> |
| 28 | #include <linux/socket.h> |
| 29 | #include <linux/sockios.h> |
| 30 | #include <linux/net.h> |
| 31 | #include <linux/netdevice.h> |
| 32 | #include <linux/in6.h> |
| 33 | #include <linux/icmpv6.h> |
| 34 | |
| 35 | #include <net/sock.h> |
| 36 | #include <net/snmp.h> |
| 37 | |
| 38 | #include <net/ipv6.h> |
| 39 | #include <net/protocol.h> |
| 40 | #include <net/transp_v6.h> |
| 41 | #include <net/rawv6.h> |
| 42 | #include <net/ndisc.h> |
| 43 | #include <net/ip6_route.h> |
| 44 | #include <net/addrconf.h> |
| 45 | #ifdef CONFIG_IPV6_MIP6 |
| 46 | #include <net/xfrm.h> |
| 47 | #endif |
| 48 | |
| 49 | #include <asm/uaccess.h> |
| 50 | |
| 51 | int ipv6_find_tlv(struct sk_buff *skb, int offset, int type) |
| 52 | { |
| 53 | int packet_len = skb->tail - skb->nh.raw; |
| 54 | struct ipv6_opt_hdr *hdr; |
| 55 | int len; |
| 56 | |
| 57 | if (offset + 2 > packet_len) |
| 58 | goto bad; |
| 59 | hdr = (struct ipv6_opt_hdr*)(skb->nh.raw + offset); |
| 60 | len = ((hdr->hdrlen + 1) << 3); |
| 61 | |
| 62 | if (offset + len > packet_len) |
| 63 | goto bad; |
| 64 | |
| 65 | offset += 2; |
| 66 | len -= 2; |
| 67 | |
| 68 | while (len > 0) { |
| 69 | int opttype = skb->nh.raw[offset]; |
| 70 | int optlen; |
| 71 | |
| 72 | if (opttype == type) |
| 73 | return offset; |
| 74 | |
| 75 | switch (opttype) { |
| 76 | case IPV6_TLV_PAD0: |
| 77 | optlen = 1; |
| 78 | break; |
| 79 | default: |
| 80 | optlen = skb->nh.raw[offset + 1] + 2; |
| 81 | if (optlen > len) |
| 82 | goto bad; |
| 83 | break; |
| 84 | } |
| 85 | offset += optlen; |
| 86 | len -= optlen; |
| 87 | } |
| 88 | /* not_found */ |
| 89 | bad: |
| 90 | return -1; |
| 91 | } |
| 92 | |
| 93 | /* |
| 94 | * Parsing tlv encoded headers. |
| 95 | * |
| 96 | * Parsing function "func" returns 1, if parsing succeed |
| 97 | * and 0, if it failed. |
| 98 | * It MUST NOT touch skb->h. |
| 99 | */ |
| 100 | |
| 101 | struct tlvtype_proc { |
| 102 | int type; |
| 103 | int (*func)(struct sk_buff **skbp, int offset); |
| 104 | }; |
| 105 | |
| 106 | /********************* |
| 107 | Generic functions |
| 108 | *********************/ |
| 109 | |
| 110 | /* An unknown option is detected, decide what to do */ |
| 111 | |
| 112 | static int ip6_tlvopt_unknown(struct sk_buff **skbp, int optoff) |
| 113 | { |
| 114 | struct sk_buff *skb = *skbp; |
| 115 | |
| 116 | switch ((skb->nh.raw[optoff] & 0xC0) >> 6) { |
| 117 | case 0: /* ignore */ |
| 118 | return 1; |
| 119 | |
| 120 | case 1: /* drop packet */ |
| 121 | break; |
| 122 | |
| 123 | case 3: /* Send ICMP if not a multicast address and drop packet */ |
| 124 | /* Actually, it is redundant check. icmp_send |
| 125 | will recheck in any case. |
| 126 | */ |
| 127 | if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr)) |
| 128 | break; |
| 129 | case 2: /* send ICMP PARM PROB regardless and drop packet */ |
| 130 | icmpv6_param_prob(skb, ICMPV6_UNK_OPTION, optoff); |
| 131 | return 0; |
| 132 | }; |
| 133 | |
| 134 | kfree_skb(skb); |
| 135 | return 0; |
| 136 | } |
| 137 | |
| 138 | /* Parse tlv encoded option header (hop-by-hop or destination) */ |
| 139 | |
| 140 | static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp) |
| 141 | { |
| 142 | struct sk_buff *skb = *skbp; |
| 143 | struct tlvtype_proc *curr; |
| 144 | int off = skb->h.raw - skb->nh.raw; |
| 145 | int len = ((skb->h.raw[1]+1)<<3); |
| 146 | |
| 147 | if ((skb->h.raw + len) - skb->data > skb_headlen(skb)) |
| 148 | goto bad; |
| 149 | |
| 150 | off += 2; |
| 151 | len -= 2; |
| 152 | |
| 153 | while (len > 0) { |
| 154 | int optlen = skb->nh.raw[off+1]+2; |
| 155 | |
| 156 | switch (skb->nh.raw[off]) { |
| 157 | case IPV6_TLV_PAD0: |
| 158 | optlen = 1; |
| 159 | break; |
| 160 | |
| 161 | case IPV6_TLV_PADN: |
| 162 | break; |
| 163 | |
| 164 | default: /* Other TLV code so scan list */ |
| 165 | if (optlen > len) |
| 166 | goto bad; |
| 167 | for (curr=procs; curr->type >= 0; curr++) { |
| 168 | if (curr->type == skb->nh.raw[off]) { |
| 169 | /* type specific length/alignment |
| 170 | checks will be performed in the |
| 171 | func(). */ |
| 172 | if (curr->func(skbp, off) == 0) |
| 173 | return 0; |
| 174 | break; |
| 175 | } |
| 176 | } |
| 177 | if (curr->type < 0) { |
| 178 | if (ip6_tlvopt_unknown(skbp, off) == 0) |
| 179 | return 0; |
| 180 | } |
| 181 | break; |
| 182 | } |
| 183 | off += optlen; |
| 184 | len -= optlen; |
| 185 | } |
| 186 | if (len == 0) |
| 187 | return 1; |
| 188 | bad: |
| 189 | kfree_skb(skb); |
| 190 | return 0; |
| 191 | } |
| 192 | |
| 193 | /***************************** |
| 194 | Destination options header. |
| 195 | *****************************/ |
| 196 | |
| 197 | #ifdef CONFIG_IPV6_MIP6 |
| 198 | static int ipv6_dest_hao(struct sk_buff **skbp, int optoff) |
| 199 | { |
| 200 | struct sk_buff *skb = *skbp; |
| 201 | struct ipv6_destopt_hao *hao; |
| 202 | struct inet6_skb_parm *opt = IP6CB(skb); |
| 203 | struct ipv6hdr *ipv6h = (struct ipv6hdr *)skb->nh.raw; |
| 204 | struct in6_addr tmp_addr; |
| 205 | int ret; |
| 206 | |
| 207 | if (opt->dsthao) { |
| 208 | LIMIT_NETDEBUG(KERN_DEBUG "hao duplicated\n"); |
| 209 | goto discard; |
| 210 | } |
| 211 | opt->dsthao = opt->dst1; |
| 212 | opt->dst1 = 0; |
| 213 | |
| 214 | hao = (struct ipv6_destopt_hao *)(skb->nh.raw + optoff); |
| 215 | |
| 216 | if (hao->length != 16) { |
| 217 | LIMIT_NETDEBUG( |
| 218 | KERN_DEBUG "hao invalid option length = %d\n", hao->length); |
| 219 | goto discard; |
| 220 | } |
| 221 | |
| 222 | if (!(ipv6_addr_type(&hao->addr) & IPV6_ADDR_UNICAST)) { |
| 223 | LIMIT_NETDEBUG( |
| 224 | KERN_DEBUG "hao is not an unicast addr: " NIP6_FMT "\n", NIP6(hao->addr)); |
| 225 | goto discard; |
| 226 | } |
| 227 | |
| 228 | ret = xfrm6_input_addr(skb, (xfrm_address_t *)&ipv6h->daddr, |
| 229 | (xfrm_address_t *)&hao->addr, IPPROTO_DSTOPTS); |
| 230 | if (unlikely(ret < 0)) |
| 231 | goto discard; |
| 232 | |
| 233 | if (skb_cloned(skb)) { |
| 234 | struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC); |
| 235 | struct inet6_skb_parm *opt2; |
| 236 | |
| 237 | if (skb2 == NULL) |
| 238 | goto discard; |
| 239 | |
| 240 | opt2 = IP6CB(skb2); |
| 241 | memcpy(opt2, opt, sizeof(*opt2)); |
| 242 | |
| 243 | kfree_skb(skb); |
| 244 | |
| 245 | /* update all variable using below by copied skbuff */ |
| 246 | *skbp = skb = skb2; |
| 247 | hao = (struct ipv6_destopt_hao *)(skb2->nh.raw + optoff); |
| 248 | ipv6h = (struct ipv6hdr *)skb2->nh.raw; |
| 249 | } |
| 250 | |
| 251 | if (skb->ip_summed == CHECKSUM_COMPLETE) |
| 252 | skb->ip_summed = CHECKSUM_NONE; |
| 253 | |
| 254 | ipv6_addr_copy(&tmp_addr, &ipv6h->saddr); |
| 255 | ipv6_addr_copy(&ipv6h->saddr, &hao->addr); |
| 256 | ipv6_addr_copy(&hao->addr, &tmp_addr); |
| 257 | |
| 258 | if (skb->tstamp.tv64 == 0) |
| 259 | __net_timestamp(skb); |
| 260 | |
| 261 | return 1; |
| 262 | |
| 263 | discard: |
| 264 | kfree_skb(skb); |
| 265 | return 0; |
| 266 | } |
| 267 | #endif |
| 268 | |
| 269 | static struct tlvtype_proc tlvprocdestopt_lst[] = { |
| 270 | #ifdef CONFIG_IPV6_MIP6 |
| 271 | { |
| 272 | .type = IPV6_TLV_HAO, |
| 273 | .func = ipv6_dest_hao, |
| 274 | }, |
| 275 | #endif |
| 276 | {-1, NULL} |
| 277 | }; |
| 278 | |
| 279 | static int ipv6_destopt_rcv(struct sk_buff **skbp) |
| 280 | { |
| 281 | struct sk_buff *skb = *skbp; |
| 282 | struct inet6_skb_parm *opt = IP6CB(skb); |
| 283 | #ifdef CONFIG_IPV6_MIP6 |
| 284 | __u16 dstbuf; |
| 285 | #endif |
| 286 | struct dst_entry *dst; |
| 287 | |
| 288 | if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) || |
| 289 | !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) { |
| 290 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 291 | IPSTATS_MIB_INHDRERRORS); |
| 292 | kfree_skb(skb); |
| 293 | return -1; |
| 294 | } |
| 295 | |
| 296 | opt->lastopt = skb->h.raw - skb->nh.raw; |
| 297 | opt->dst1 = skb->h.raw - skb->nh.raw; |
| 298 | #ifdef CONFIG_IPV6_MIP6 |
| 299 | dstbuf = opt->dst1; |
| 300 | #endif |
| 301 | |
| 302 | dst = dst_clone(skb->dst); |
| 303 | if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) { |
| 304 | dst_release(dst); |
| 305 | skb = *skbp; |
| 306 | skb->h.raw += ((skb->h.raw[1]+1)<<3); |
| 307 | opt = IP6CB(skb); |
| 308 | #ifdef CONFIG_IPV6_MIP6 |
| 309 | opt->nhoff = dstbuf; |
| 310 | #else |
| 311 | opt->nhoff = opt->dst1; |
| 312 | #endif |
| 313 | return 1; |
| 314 | } |
| 315 | |
| 316 | IP6_INC_STATS_BH(ip6_dst_idev(dst), IPSTATS_MIB_INHDRERRORS); |
| 317 | dst_release(dst); |
| 318 | return -1; |
| 319 | } |
| 320 | |
| 321 | static struct inet6_protocol destopt_protocol = { |
| 322 | .handler = ipv6_destopt_rcv, |
| 323 | .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR, |
| 324 | }; |
| 325 | |
| 326 | void __init ipv6_destopt_init(void) |
| 327 | { |
| 328 | if (inet6_add_protocol(&destopt_protocol, IPPROTO_DSTOPTS) < 0) |
| 329 | printk(KERN_ERR "ipv6_destopt_init: Could not register protocol\n"); |
| 330 | } |
| 331 | |
| 332 | /******************************** |
| 333 | NONE header. No data in packet. |
| 334 | ********************************/ |
| 335 | |
| 336 | static int ipv6_nodata_rcv(struct sk_buff **skbp) |
| 337 | { |
| 338 | struct sk_buff *skb = *skbp; |
| 339 | |
| 340 | kfree_skb(skb); |
| 341 | return 0; |
| 342 | } |
| 343 | |
| 344 | static struct inet6_protocol nodata_protocol = { |
| 345 | .handler = ipv6_nodata_rcv, |
| 346 | .flags = INET6_PROTO_NOPOLICY, |
| 347 | }; |
| 348 | |
| 349 | void __init ipv6_nodata_init(void) |
| 350 | { |
| 351 | if (inet6_add_protocol(&nodata_protocol, IPPROTO_NONE) < 0) |
| 352 | printk(KERN_ERR "ipv6_nodata_init: Could not register protocol\n"); |
| 353 | } |
| 354 | |
| 355 | /******************************** |
| 356 | Routing header. |
| 357 | ********************************/ |
| 358 | |
| 359 | static int ipv6_rthdr_rcv(struct sk_buff **skbp) |
| 360 | { |
| 361 | struct sk_buff *skb = *skbp; |
| 362 | struct inet6_skb_parm *opt = IP6CB(skb); |
| 363 | struct in6_addr *addr = NULL; |
| 364 | struct in6_addr daddr; |
| 365 | struct inet6_dev *idev; |
| 366 | int n, i; |
| 367 | struct ipv6_rt_hdr *hdr; |
| 368 | struct rt0_hdr *rthdr; |
| 369 | int accept_source_route = ipv6_devconf.accept_source_route; |
| 370 | |
| 371 | if (accept_source_route < 0 || |
| 372 | ((idev = in6_dev_get(skb->dev)) == NULL)) { |
| 373 | kfree_skb(skb); |
| 374 | return -1; |
| 375 | } |
| 376 | if (idev->cnf.accept_source_route < 0) { |
| 377 | in6_dev_put(idev); |
| 378 | kfree_skb(skb); |
| 379 | return -1; |
| 380 | } |
| 381 | |
| 382 | if (accept_source_route > idev->cnf.accept_source_route) |
| 383 | accept_source_route = idev->cnf.accept_source_route; |
| 384 | |
| 385 | in6_dev_put(idev); |
| 386 | |
| 387 | if (!pskb_may_pull(skb, (skb->h.raw-skb->data)+8) || |
| 388 | !pskb_may_pull(skb, (skb->h.raw-skb->data)+((skb->h.raw[1]+1)<<3))) { |
| 389 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 390 | IPSTATS_MIB_INHDRERRORS); |
| 391 | kfree_skb(skb); |
| 392 | return -1; |
| 393 | } |
| 394 | |
| 395 | hdr = (struct ipv6_rt_hdr *) skb->h.raw; |
| 396 | |
| 397 | switch (hdr->type) { |
| 398 | #ifdef CONFIG_IPV6_MIP6 |
| 399 | break; |
| 400 | #endif |
| 401 | case IPV6_SRCRT_TYPE_0: |
| 402 | if (accept_source_route > 0) |
| 403 | break; |
| 404 | kfree_skb(skb); |
| 405 | return -1; |
| 406 | default: |
| 407 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 408 | IPSTATS_MIB_INHDRERRORS); |
| 409 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->type) - skb->nh.raw); |
| 410 | return -1; |
| 411 | } |
| 412 | |
| 413 | if (ipv6_addr_is_multicast(&skb->nh.ipv6h->daddr) || |
| 414 | skb->pkt_type != PACKET_HOST) { |
| 415 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 416 | IPSTATS_MIB_INADDRERRORS); |
| 417 | kfree_skb(skb); |
| 418 | return -1; |
| 419 | } |
| 420 | |
| 421 | looped_back: |
| 422 | if (hdr->segments_left == 0) { |
| 423 | switch (hdr->type) { |
| 424 | #ifdef CONFIG_IPV6_MIP6 |
| 425 | case IPV6_SRCRT_TYPE_2: |
| 426 | /* Silently discard type 2 header unless it was |
| 427 | * processed by own |
| 428 | */ |
| 429 | if (!addr) { |
| 430 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 431 | IPSTATS_MIB_INADDRERRORS); |
| 432 | kfree_skb(skb); |
| 433 | return -1; |
| 434 | } |
| 435 | break; |
| 436 | #endif |
| 437 | default: |
| 438 | break; |
| 439 | } |
| 440 | |
| 441 | opt->lastopt = skb->h.raw - skb->nh.raw; |
| 442 | opt->srcrt = skb->h.raw - skb->nh.raw; |
| 443 | skb->h.raw += (hdr->hdrlen + 1) << 3; |
| 444 | opt->dst0 = opt->dst1; |
| 445 | opt->dst1 = 0; |
| 446 | opt->nhoff = (&hdr->nexthdr) - skb->nh.raw; |
| 447 | return 1; |
| 448 | } |
| 449 | |
| 450 | switch (hdr->type) { |
| 451 | case IPV6_SRCRT_TYPE_0: |
| 452 | if (hdr->hdrlen & 0x01) { |
| 453 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 454 | IPSTATS_MIB_INHDRERRORS); |
| 455 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->hdrlen) - skb->nh.raw); |
| 456 | return -1; |
| 457 | } |
| 458 | break; |
| 459 | #ifdef CONFIG_IPV6_MIP6 |
| 460 | case IPV6_SRCRT_TYPE_2: |
| 461 | /* Silently discard invalid RTH type 2 */ |
| 462 | if (hdr->hdrlen != 2 || hdr->segments_left != 1) { |
| 463 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 464 | IPSTATS_MIB_INHDRERRORS); |
| 465 | kfree_skb(skb); |
| 466 | return -1; |
| 467 | } |
| 468 | break; |
| 469 | #endif |
| 470 | } |
| 471 | |
| 472 | /* |
| 473 | * This is the routing header forwarding algorithm from |
| 474 | * RFC 2460, page 16. |
| 475 | */ |
| 476 | |
| 477 | n = hdr->hdrlen >> 1; |
| 478 | |
| 479 | if (hdr->segments_left > n) { |
| 480 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 481 | IPSTATS_MIB_INHDRERRORS); |
| 482 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, (&hdr->segments_left) - skb->nh.raw); |
| 483 | return -1; |
| 484 | } |
| 485 | |
| 486 | /* We are about to mangle packet header. Be careful! |
| 487 | Do not damage packets queued somewhere. |
| 488 | */ |
| 489 | if (skb_cloned(skb)) { |
| 490 | struct sk_buff *skb2 = skb_copy(skb, GFP_ATOMIC); |
| 491 | /* the copy is a forwarded packet */ |
| 492 | if (skb2 == NULL) { |
| 493 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 494 | IPSTATS_MIB_OUTDISCARDS); |
| 495 | kfree_skb(skb); |
| 496 | return -1; |
| 497 | } |
| 498 | kfree_skb(skb); |
| 499 | *skbp = skb = skb2; |
| 500 | opt = IP6CB(skb2); |
| 501 | hdr = (struct ipv6_rt_hdr *) skb2->h.raw; |
| 502 | } |
| 503 | |
| 504 | if (skb->ip_summed == CHECKSUM_COMPLETE) |
| 505 | skb->ip_summed = CHECKSUM_NONE; |
| 506 | |
| 507 | i = n - --hdr->segments_left; |
| 508 | |
| 509 | rthdr = (struct rt0_hdr *) hdr; |
| 510 | addr = rthdr->addr; |
| 511 | addr += i - 1; |
| 512 | |
| 513 | switch (hdr->type) { |
| 514 | #ifdef CONFIG_IPV6_MIP6 |
| 515 | case IPV6_SRCRT_TYPE_2: |
| 516 | if (xfrm6_input_addr(skb, (xfrm_address_t *)addr, |
| 517 | (xfrm_address_t *)&skb->nh.ipv6h->saddr, |
| 518 | IPPROTO_ROUTING) < 0) { |
| 519 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 520 | IPSTATS_MIB_INADDRERRORS); |
| 521 | kfree_skb(skb); |
| 522 | return -1; |
| 523 | } |
| 524 | if (!ipv6_chk_home_addr(addr)) { |
| 525 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 526 | IPSTATS_MIB_INADDRERRORS); |
| 527 | kfree_skb(skb); |
| 528 | return -1; |
| 529 | } |
| 530 | break; |
| 531 | #endif |
| 532 | default: |
| 533 | break; |
| 534 | } |
| 535 | |
| 536 | if (ipv6_addr_is_multicast(addr)) { |
| 537 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 538 | IPSTATS_MIB_INADDRERRORS); |
| 539 | kfree_skb(skb); |
| 540 | return -1; |
| 541 | } |
| 542 | |
| 543 | ipv6_addr_copy(&daddr, addr); |
| 544 | ipv6_addr_copy(addr, &skb->nh.ipv6h->daddr); |
| 545 | ipv6_addr_copy(&skb->nh.ipv6h->daddr, &daddr); |
| 546 | |
| 547 | dst_release(xchg(&skb->dst, NULL)); |
| 548 | ip6_route_input(skb); |
| 549 | if (skb->dst->error) { |
| 550 | skb_push(skb, skb->data - skb->nh.raw); |
| 551 | dst_input(skb); |
| 552 | return -1; |
| 553 | } |
| 554 | |
| 555 | if (skb->dst->dev->flags&IFF_LOOPBACK) { |
| 556 | if (skb->nh.ipv6h->hop_limit <= 1) { |
| 557 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 558 | IPSTATS_MIB_INHDRERRORS); |
| 559 | icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, |
| 560 | 0, skb->dev); |
| 561 | kfree_skb(skb); |
| 562 | return -1; |
| 563 | } |
| 564 | skb->nh.ipv6h->hop_limit--; |
| 565 | goto looped_back; |
| 566 | } |
| 567 | |
| 568 | skb_push(skb, skb->data - skb->nh.raw); |
| 569 | dst_input(skb); |
| 570 | return -1; |
| 571 | } |
| 572 | |
| 573 | static struct inet6_protocol rthdr_protocol = { |
| 574 | .handler = ipv6_rthdr_rcv, |
| 575 | .flags = INET6_PROTO_NOPOLICY | INET6_PROTO_GSO_EXTHDR, |
| 576 | }; |
| 577 | |
| 578 | void __init ipv6_rthdr_init(void) |
| 579 | { |
| 580 | if (inet6_add_protocol(&rthdr_protocol, IPPROTO_ROUTING) < 0) |
| 581 | printk(KERN_ERR "ipv6_rthdr_init: Could not register protocol\n"); |
| 582 | }; |
| 583 | |
| 584 | /* |
| 585 | This function inverts received rthdr. |
| 586 | NOTE: specs allow to make it automatically only if |
| 587 | packet authenticated. |
| 588 | |
| 589 | I will not discuss it here (though, I am really pissed off at |
| 590 | this stupid requirement making rthdr idea useless) |
| 591 | |
| 592 | Actually, it creates severe problems for us. |
| 593 | Embryonic requests has no associated sockets, |
| 594 | so that user have no control over it and |
| 595 | cannot not only to set reply options, but |
| 596 | even to know, that someone wants to connect |
| 597 | without success. :-( |
| 598 | |
| 599 | For now we need to test the engine, so that I created |
| 600 | temporary (or permanent) backdoor. |
| 601 | If listening socket set IPV6_RTHDR to 2, then we invert header. |
| 602 | --ANK (980729) |
| 603 | */ |
| 604 | |
| 605 | struct ipv6_txoptions * |
| 606 | ipv6_invert_rthdr(struct sock *sk, struct ipv6_rt_hdr *hdr) |
| 607 | { |
| 608 | /* Received rthdr: |
| 609 | |
| 610 | [ H1 -> H2 -> ... H_prev ] daddr=ME |
| 611 | |
| 612 | Inverted result: |
| 613 | [ H_prev -> ... -> H1 ] daddr =sender |
| 614 | |
| 615 | Note, that IP output engine will rewrite this rthdr |
| 616 | by rotating it left by one addr. |
| 617 | */ |
| 618 | |
| 619 | int n, i; |
| 620 | struct rt0_hdr *rthdr = (struct rt0_hdr*)hdr; |
| 621 | struct rt0_hdr *irthdr; |
| 622 | struct ipv6_txoptions *opt; |
| 623 | int hdrlen = ipv6_optlen(hdr); |
| 624 | |
| 625 | if (hdr->segments_left || |
| 626 | hdr->type != IPV6_SRCRT_TYPE_0 || |
| 627 | hdr->hdrlen & 0x01) |
| 628 | return NULL; |
| 629 | |
| 630 | n = hdr->hdrlen >> 1; |
| 631 | opt = sock_kmalloc(sk, sizeof(*opt) + hdrlen, GFP_ATOMIC); |
| 632 | if (opt == NULL) |
| 633 | return NULL; |
| 634 | memset(opt, 0, sizeof(*opt)); |
| 635 | opt->tot_len = sizeof(*opt) + hdrlen; |
| 636 | opt->srcrt = (void*)(opt+1); |
| 637 | opt->opt_nflen = hdrlen; |
| 638 | |
| 639 | memcpy(opt->srcrt, hdr, sizeof(*hdr)); |
| 640 | irthdr = (struct rt0_hdr*)opt->srcrt; |
| 641 | irthdr->reserved = 0; |
| 642 | opt->srcrt->segments_left = n; |
| 643 | for (i=0; i<n; i++) |
| 644 | memcpy(irthdr->addr+i, rthdr->addr+(n-1-i), 16); |
| 645 | return opt; |
| 646 | } |
| 647 | |
| 648 | EXPORT_SYMBOL_GPL(ipv6_invert_rthdr); |
| 649 | |
| 650 | /********************************** |
| 651 | Hop-by-hop options. |
| 652 | **********************************/ |
| 653 | |
| 654 | /* Router Alert as of RFC 2711 */ |
| 655 | |
| 656 | static int ipv6_hop_ra(struct sk_buff **skbp, int optoff) |
| 657 | { |
| 658 | struct sk_buff *skb = *skbp; |
| 659 | |
| 660 | if (skb->nh.raw[optoff+1] == 2) { |
| 661 | IP6CB(skb)->ra = optoff; |
| 662 | return 1; |
| 663 | } |
| 664 | LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_ra: wrong RA length %d\n", |
| 665 | skb->nh.raw[optoff+1]); |
| 666 | kfree_skb(skb); |
| 667 | return 0; |
| 668 | } |
| 669 | |
| 670 | /* Jumbo payload */ |
| 671 | |
| 672 | static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff) |
| 673 | { |
| 674 | struct sk_buff *skb = *skbp; |
| 675 | u32 pkt_len; |
| 676 | |
| 677 | if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) { |
| 678 | LIMIT_NETDEBUG(KERN_DEBUG "ipv6_hop_jumbo: wrong jumbo opt length/alignment %d\n", |
| 679 | skb->nh.raw[optoff+1]); |
| 680 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), |
| 681 | IPSTATS_MIB_INHDRERRORS); |
| 682 | goto drop; |
| 683 | } |
| 684 | |
| 685 | pkt_len = ntohl(*(__be32*)(skb->nh.raw+optoff+2)); |
| 686 | if (pkt_len <= IPV6_MAXPLEN) { |
| 687 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); |
| 688 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff+2); |
| 689 | return 0; |
| 690 | } |
| 691 | if (skb->nh.ipv6h->payload_len) { |
| 692 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INHDRERRORS); |
| 693 | icmpv6_param_prob(skb, ICMPV6_HDR_FIELD, optoff); |
| 694 | return 0; |
| 695 | } |
| 696 | |
| 697 | if (pkt_len > skb->len - sizeof(struct ipv6hdr)) { |
| 698 | IP6_INC_STATS_BH(ip6_dst_idev(skb->dst), IPSTATS_MIB_INTRUNCATEDPKTS); |
| 699 | goto drop; |
| 700 | } |
| 701 | |
| 702 | if (pskb_trim_rcsum(skb, pkt_len + sizeof(struct ipv6hdr))) |
| 703 | goto drop; |
| 704 | |
| 705 | return 1; |
| 706 | |
| 707 | drop: |
| 708 | kfree_skb(skb); |
| 709 | return 0; |
| 710 | } |
| 711 | |
| 712 | static struct tlvtype_proc tlvprochopopt_lst[] = { |
| 713 | { |
| 714 | .type = IPV6_TLV_ROUTERALERT, |
| 715 | .func = ipv6_hop_ra, |
| 716 | }, |
| 717 | { |
| 718 | .type = IPV6_TLV_JUMBO, |
| 719 | .func = ipv6_hop_jumbo, |
| 720 | }, |
| 721 | { -1, } |
| 722 | }; |
| 723 | |
| 724 | int ipv6_parse_hopopts(struct sk_buff **skbp) |
| 725 | { |
| 726 | struct sk_buff *skb = *skbp; |
| 727 | struct inet6_skb_parm *opt = IP6CB(skb); |
| 728 | |
| 729 | /* |
| 730 | * skb->nh.raw is equal to skb->data, and |
| 731 | * skb->h.raw - skb->nh.raw is always equal to |
| 732 | * sizeof(struct ipv6hdr) by definition of |
| 733 | * hop-by-hop options. |
| 734 | */ |
| 735 | if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + 8) || |
| 736 | !pskb_may_pull(skb, sizeof(struct ipv6hdr) + ((skb->h.raw[1] + 1) << 3))) { |
| 737 | kfree_skb(skb); |
| 738 | return -1; |
| 739 | } |
| 740 | |
| 741 | opt->hop = sizeof(struct ipv6hdr); |
| 742 | if (ip6_parse_tlv(tlvprochopopt_lst, skbp)) { |
| 743 | skb = *skbp; |
| 744 | skb->h.raw += (skb->h.raw[1]+1)<<3; |
| 745 | opt = IP6CB(skb); |
| 746 | opt->nhoff = sizeof(struct ipv6hdr); |
| 747 | return 1; |
| 748 | } |
| 749 | return -1; |
| 750 | } |
| 751 | |
| 752 | /* |
| 753 | * Creating outbound headers. |
| 754 | * |
| 755 | * "build" functions work when skb is filled from head to tail (datagram) |
| 756 | * "push" functions work when headers are added from tail to head (tcp) |
| 757 | * |
| 758 | * In both cases we assume, that caller reserved enough room |
| 759 | * for headers. |
| 760 | */ |
| 761 | |
| 762 | static void ipv6_push_rthdr(struct sk_buff *skb, u8 *proto, |
| 763 | struct ipv6_rt_hdr *opt, |
| 764 | struct in6_addr **addr_p) |
| 765 | { |
| 766 | struct rt0_hdr *phdr, *ihdr; |
| 767 | int hops; |
| 768 | |
| 769 | ihdr = (struct rt0_hdr *) opt; |
| 770 | |
| 771 | phdr = (struct rt0_hdr *) skb_push(skb, (ihdr->rt_hdr.hdrlen + 1) << 3); |
| 772 | memcpy(phdr, ihdr, sizeof(struct rt0_hdr)); |
| 773 | |
| 774 | hops = ihdr->rt_hdr.hdrlen >> 1; |
| 775 | |
| 776 | if (hops > 1) |
| 777 | memcpy(phdr->addr, ihdr->addr + 1, |
| 778 | (hops - 1) * sizeof(struct in6_addr)); |
| 779 | |
| 780 | ipv6_addr_copy(phdr->addr + (hops - 1), *addr_p); |
| 781 | *addr_p = ihdr->addr; |
| 782 | |
| 783 | phdr->rt_hdr.nexthdr = *proto; |
| 784 | *proto = NEXTHDR_ROUTING; |
| 785 | } |
| 786 | |
| 787 | static void ipv6_push_exthdr(struct sk_buff *skb, u8 *proto, u8 type, struct ipv6_opt_hdr *opt) |
| 788 | { |
| 789 | struct ipv6_opt_hdr *h = (struct ipv6_opt_hdr *)skb_push(skb, ipv6_optlen(opt)); |
| 790 | |
| 791 | memcpy(h, opt, ipv6_optlen(opt)); |
| 792 | h->nexthdr = *proto; |
| 793 | *proto = type; |
| 794 | } |
| 795 | |
| 796 | void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, |
| 797 | u8 *proto, |
| 798 | struct in6_addr **daddr) |
| 799 | { |
| 800 | if (opt->srcrt) { |
| 801 | ipv6_push_rthdr(skb, proto, opt->srcrt, daddr); |
| 802 | /* |
| 803 | * IPV6_RTHDRDSTOPTS is ignored |
| 804 | * unless IPV6_RTHDR is set (RFC3542). |
| 805 | */ |
| 806 | if (opt->dst0opt) |
| 807 | ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt); |
| 808 | } |
| 809 | if (opt->hopopt) |
| 810 | ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt); |
| 811 | } |
| 812 | |
| 813 | void ipv6_push_frag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt, u8 *proto) |
| 814 | { |
| 815 | if (opt->dst1opt) |
| 816 | ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst1opt); |
| 817 | } |
| 818 | |
| 819 | struct ipv6_txoptions * |
| 820 | ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt) |
| 821 | { |
| 822 | struct ipv6_txoptions *opt2; |
| 823 | |
| 824 | opt2 = sock_kmalloc(sk, opt->tot_len, GFP_ATOMIC); |
| 825 | if (opt2) { |
| 826 | long dif = (char*)opt2 - (char*)opt; |
| 827 | memcpy(opt2, opt, opt->tot_len); |
| 828 | if (opt2->hopopt) |
| 829 | *((char**)&opt2->hopopt) += dif; |
| 830 | if (opt2->dst0opt) |
| 831 | *((char**)&opt2->dst0opt) += dif; |
| 832 | if (opt2->dst1opt) |
| 833 | *((char**)&opt2->dst1opt) += dif; |
| 834 | if (opt2->srcrt) |
| 835 | *((char**)&opt2->srcrt) += dif; |
| 836 | } |
| 837 | return opt2; |
| 838 | } |
| 839 | |
| 840 | EXPORT_SYMBOL_GPL(ipv6_dup_options); |
| 841 | |
| 842 | static int ipv6_renew_option(void *ohdr, |
| 843 | struct ipv6_opt_hdr __user *newopt, int newoptlen, |
| 844 | int inherit, |
| 845 | struct ipv6_opt_hdr **hdr, |
| 846 | char **p) |
| 847 | { |
| 848 | if (inherit) { |
| 849 | if (ohdr) { |
| 850 | memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr)); |
| 851 | *hdr = (struct ipv6_opt_hdr *)*p; |
| 852 | *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr)); |
| 853 | } |
| 854 | } else { |
| 855 | if (newopt) { |
| 856 | if (copy_from_user(*p, newopt, newoptlen)) |
| 857 | return -EFAULT; |
| 858 | *hdr = (struct ipv6_opt_hdr *)*p; |
| 859 | if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen) |
| 860 | return -EINVAL; |
| 861 | *p += CMSG_ALIGN(newoptlen); |
| 862 | } |
| 863 | } |
| 864 | return 0; |
| 865 | } |
| 866 | |
| 867 | struct ipv6_txoptions * |
| 868 | ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt, |
| 869 | int newtype, |
| 870 | struct ipv6_opt_hdr __user *newopt, int newoptlen) |
| 871 | { |
| 872 | int tot_len = 0; |
| 873 | char *p; |
| 874 | struct ipv6_txoptions *opt2; |
| 875 | int err; |
| 876 | |
| 877 | if (opt) { |
| 878 | if (newtype != IPV6_HOPOPTS && opt->hopopt) |
| 879 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt)); |
| 880 | if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt) |
| 881 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt)); |
| 882 | if (newtype != IPV6_RTHDR && opt->srcrt) |
| 883 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt)); |
| 884 | if (newtype != IPV6_DSTOPTS && opt->dst1opt) |
| 885 | tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt)); |
| 886 | } |
| 887 | |
| 888 | if (newopt && newoptlen) |
| 889 | tot_len += CMSG_ALIGN(newoptlen); |
| 890 | |
| 891 | if (!tot_len) |
| 892 | return NULL; |
| 893 | |
| 894 | tot_len += sizeof(*opt2); |
| 895 | opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC); |
| 896 | if (!opt2) |
| 897 | return ERR_PTR(-ENOBUFS); |
| 898 | |
| 899 | memset(opt2, 0, tot_len); |
| 900 | |
| 901 | opt2->tot_len = tot_len; |
| 902 | p = (char *)(opt2 + 1); |
| 903 | |
| 904 | err = ipv6_renew_option(opt ? opt->hopopt : NULL, newopt, newoptlen, |
| 905 | newtype != IPV6_HOPOPTS, |
| 906 | &opt2->hopopt, &p); |
| 907 | if (err) |
| 908 | goto out; |
| 909 | |
| 910 | err = ipv6_renew_option(opt ? opt->dst0opt : NULL, newopt, newoptlen, |
| 911 | newtype != IPV6_RTHDRDSTOPTS, |
| 912 | &opt2->dst0opt, &p); |
| 913 | if (err) |
| 914 | goto out; |
| 915 | |
| 916 | err = ipv6_renew_option(opt ? opt->srcrt : NULL, newopt, newoptlen, |
| 917 | newtype != IPV6_RTHDR, |
| 918 | (struct ipv6_opt_hdr **)&opt2->srcrt, &p); |
| 919 | if (err) |
| 920 | goto out; |
| 921 | |
| 922 | err = ipv6_renew_option(opt ? opt->dst1opt : NULL, newopt, newoptlen, |
| 923 | newtype != IPV6_DSTOPTS, |
| 924 | &opt2->dst1opt, &p); |
| 925 | if (err) |
| 926 | goto out; |
| 927 | |
| 928 | opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) + |
| 929 | (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) + |
| 930 | (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0); |
| 931 | opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0); |
| 932 | |
| 933 | return opt2; |
| 934 | out: |
| 935 | sock_kfree_s(sk, opt2, opt2->tot_len); |
| 936 | return ERR_PTR(err); |
| 937 | } |
| 938 | |
| 939 | struct ipv6_txoptions *ipv6_fixup_options(struct ipv6_txoptions *opt_space, |
| 940 | struct ipv6_txoptions *opt) |
| 941 | { |
| 942 | /* |
| 943 | * ignore the dest before srcrt unless srcrt is being included. |
| 944 | * --yoshfuji |
| 945 | */ |
| 946 | if (opt && opt->dst0opt && !opt->srcrt) { |
| 947 | if (opt_space != opt) { |
| 948 | memcpy(opt_space, opt, sizeof(*opt_space)); |
| 949 | opt = opt_space; |
| 950 | } |
| 951 | opt->opt_nflen -= ipv6_optlen(opt->dst0opt); |
| 952 | opt->dst0opt = NULL; |
| 953 | } |
| 954 | |
| 955 | return opt; |
| 956 | } |
| 957 | |