1 /* 2 * Copyright (C)2003-2006 Helsinki University of Technology 3 * Copyright (C)2003-2006 USAGI/WIDE Project 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program; if not, see <http://www.gnu.org/licenses/>. 17 */ 18 /* 19 * Authors: 20 * Noriaki TAKAMIYA @USAGI 21 * Masahide NAKAMURA @USAGI 22 */ 23 24 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 25 26 #include <linux/module.h> 27 #include <linux/skbuff.h> 28 #include <linux/time.h> 29 #include <linux/ipv6.h> 30 #include <linux/icmpv6.h> 31 #include <net/sock.h> 32 #include <net/ipv6.h> 33 #include <net/ip6_checksum.h> 34 #include <net/rawv6.h> 35 #include <net/xfrm.h> 36 #include <net/mip6.h> 37 38 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 39 { 40 return (n - len + 16) & 0x7; 41 } 42 43 static inline void *mip6_padn(__u8 *data, __u8 padlen) 44 { 45 if (!data) 46 return NULL; 47 if (padlen == 1) { 48 data[0] = IPV6_TLV_PAD1; 49 } else if (padlen > 1) { 50 data[0] = IPV6_TLV_PADN; 51 data[1] = padlen - 2; 52 if (padlen > 2) 53 memset(data+2, 0, data[1]); 54 } 55 return data + padlen; 56 } 57 58 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos) 59 { 60 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); 61 } 62 63 static int mip6_mh_len(int type) 64 { 65 int len = 0; 66 67 switch (type) { 68 case IP6_MH_TYPE_BRR: 69 len = 0; 70 break; 71 case IP6_MH_TYPE_HOTI: 72 case IP6_MH_TYPE_COTI: 73 case IP6_MH_TYPE_BU: 74 case IP6_MH_TYPE_BACK: 75 len = 1; 76 break; 77 case IP6_MH_TYPE_HOT: 78 case IP6_MH_TYPE_COT: 79 case IP6_MH_TYPE_BERROR: 80 len = 2; 81 break; 82 } 83 return len; 84 } 85 86 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 87 { 88 struct ip6_mh _hdr; 89 const struct ip6_mh *mh; 90 91 mh = skb_header_pointer(skb, skb_transport_offset(skb), 92 sizeof(_hdr), &_hdr); 93 if (!mh) 94 return -1; 95 96 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len) 97 return -1; 98 99 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 100 net_dbg_ratelimited("mip6: MH message too short: %d vs >=%d\n", 101 mh->ip6mh_hdrlen, 102 mip6_mh_len(mh->ip6mh_type)); 103 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) + 104 skb_network_header_len(skb)); 105 return -1; 106 } 107 108 if (mh->ip6mh_proto != IPPROTO_NONE) { 109 net_dbg_ratelimited("mip6: MH invalid payload proto = %d\n", 110 mh->ip6mh_proto); 111 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) + 112 skb_network_header_len(skb)); 113 return -1; 114 } 115 116 return 0; 117 } 118 119 struct mip6_report_rate_limiter { 120 spinlock_t lock; 121 struct timeval stamp; 122 int iif; 123 struct in6_addr src; 124 struct in6_addr dst; 125 }; 126 127 static struct mip6_report_rate_limiter mip6_report_rl = { 128 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 129 }; 130 131 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 132 { 133 const struct ipv6hdr *iph = ipv6_hdr(skb); 134 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 135 int err = destopt->nexthdr; 136 137 spin_lock(&x->lock); 138 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 139 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 140 err = -ENOENT; 141 spin_unlock(&x->lock); 142 143 return err; 144 } 145 146 /* Destination Option Header is inserted. 147 * IP Header's src address is replaced with Home Address Option in 148 * Destination Option Header. 149 */ 150 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 151 { 152 struct ipv6hdr *iph; 153 struct ipv6_destopt_hdr *dstopt; 154 struct ipv6_destopt_hao *hao; 155 u8 nexthdr; 156 int len; 157 158 skb_push(skb, -skb_network_offset(skb)); 159 iph = ipv6_hdr(skb); 160 161 nexthdr = *skb_mac_header(skb); 162 *skb_mac_header(skb) = IPPROTO_DSTOPTS; 163 164 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 165 dstopt->nexthdr = nexthdr; 166 167 hao = mip6_padn((char *)(dstopt + 1), 168 calc_padlen(sizeof(*dstopt), 6)); 169 170 hao->type = IPV6_TLV_HAO; 171 BUILD_BUG_ON(sizeof(*hao) != 18); 172 hao->length = sizeof(*hao) - 2; 173 174 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 175 176 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 177 spin_lock_bh(&x->lock); 178 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 179 spin_unlock_bh(&x->lock); 180 181 WARN_ON(len != x->props.header_len); 182 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 183 184 return 0; 185 } 186 187 static inline int mip6_report_rl_allow(struct timeval *stamp, 188 const struct in6_addr *dst, 189 const struct in6_addr *src, int iif) 190 { 191 int allow = 0; 192 193 spin_lock_bh(&mip6_report_rl.lock); 194 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || 195 mip6_report_rl.stamp.tv_usec != stamp->tv_usec || 196 mip6_report_rl.iif != iif || 197 !ipv6_addr_equal(&mip6_report_rl.src, src) || 198 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 199 mip6_report_rl.stamp.tv_sec = stamp->tv_sec; 200 mip6_report_rl.stamp.tv_usec = stamp->tv_usec; 201 mip6_report_rl.iif = iif; 202 mip6_report_rl.src = *src; 203 mip6_report_rl.dst = *dst; 204 allow = 1; 205 } 206 spin_unlock_bh(&mip6_report_rl.lock); 207 return allow; 208 } 209 210 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, 211 const struct flowi *fl) 212 { 213 struct net *net = xs_net(x); 214 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 215 const struct flowi6 *fl6 = &fl->u.ip6; 216 struct ipv6_destopt_hao *hao = NULL; 217 struct xfrm_selector sel; 218 int offset; 219 struct timeval stamp; 220 int err = 0; 221 222 if (unlikely(fl6->flowi6_proto == IPPROTO_MH && 223 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX)) 224 goto out; 225 226 if (likely(opt->dsthao)) { 227 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 228 if (likely(offset >= 0)) 229 hao = (struct ipv6_destopt_hao *) 230 (skb_network_header(skb) + offset); 231 } 232 233 skb_get_timestamp(skb, &stamp); 234 235 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 236 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 237 opt->iif)) 238 goto out; 239 240 memset(&sel, 0, sizeof(sel)); 241 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 242 sizeof(sel.daddr)); 243 sel.prefixlen_d = 128; 244 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 245 sizeof(sel.saddr)); 246 sel.prefixlen_s = 128; 247 sel.family = AF_INET6; 248 sel.proto = fl6->flowi6_proto; 249 sel.dport = xfrm_flowi_dport(fl, &fl6->uli); 250 if (sel.dport) 251 sel.dport_mask = htons(~0); 252 sel.sport = xfrm_flowi_sport(fl, &fl6->uli); 253 if (sel.sport) 254 sel.sport_mask = htons(~0); 255 sel.ifindex = fl6->flowi6_oif; 256 257 err = km_report(net, IPPROTO_DSTOPTS, &sel, 258 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 259 260 out: 261 return err; 262 } 263 264 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 265 u8 **nexthdr) 266 { 267 u16 offset = sizeof(struct ipv6hdr); 268 struct ipv6_opt_hdr *exthdr = 269 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 270 const unsigned char *nh = skb_network_header(skb); 271 unsigned int packet_len = skb_tail_pointer(skb) - 272 skb_network_header(skb); 273 int found_rhdr = 0; 274 275 *nexthdr = &ipv6_hdr(skb)->nexthdr; 276 277 while (offset + 1 <= packet_len) { 278 279 switch (**nexthdr) { 280 case NEXTHDR_HOP: 281 break; 282 case NEXTHDR_ROUTING: 283 found_rhdr = 1; 284 break; 285 case NEXTHDR_DEST: 286 /* 287 * HAO MUST NOT appear more than once. 288 * XXX: It is better to try to find by the end of 289 * XXX: packet if HAO exists. 290 */ 291 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 292 net_dbg_ratelimited("mip6: hao exists already, override\n"); 293 return offset; 294 } 295 296 if (found_rhdr) 297 return offset; 298 299 break; 300 default: 301 return offset; 302 } 303 304 offset += ipv6_optlen(exthdr); 305 *nexthdr = &exthdr->nexthdr; 306 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 307 } 308 309 return offset; 310 } 311 312 static int mip6_destopt_init_state(struct xfrm_state *x) 313 { 314 if (x->id.spi) { 315 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 316 return -EINVAL; 317 } 318 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 319 pr_info("%s: state's mode is not %u: %u\n", 320 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 321 return -EINVAL; 322 } 323 324 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 325 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 326 sizeof(struct ipv6_destopt_hao); 327 WARN_ON(x->props.header_len != 24); 328 329 return 0; 330 } 331 332 /* 333 * Do nothing about destroying since it has no specific operation for 334 * destination options header unlike IPsec protocols. 335 */ 336 static void mip6_destopt_destroy(struct xfrm_state *x) 337 { 338 } 339 340 static const struct xfrm_type mip6_destopt_type = { 341 .description = "MIP6DESTOPT", 342 .owner = THIS_MODULE, 343 .proto = IPPROTO_DSTOPTS, 344 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 345 .init_state = mip6_destopt_init_state, 346 .destructor = mip6_destopt_destroy, 347 .input = mip6_destopt_input, 348 .output = mip6_destopt_output, 349 .reject = mip6_destopt_reject, 350 .hdr_offset = mip6_destopt_offset, 351 }; 352 353 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 354 { 355 const struct ipv6hdr *iph = ipv6_hdr(skb); 356 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 357 int err = rt2->rt_hdr.nexthdr; 358 359 spin_lock(&x->lock); 360 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) && 361 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 362 err = -ENOENT; 363 spin_unlock(&x->lock); 364 365 return err; 366 } 367 368 /* Routing Header type 2 is inserted. 369 * IP Header's dst address is replaced with Routing Header's Home Address. 370 */ 371 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 372 { 373 struct ipv6hdr *iph; 374 struct rt2_hdr *rt2; 375 u8 nexthdr; 376 377 skb_push(skb, -skb_network_offset(skb)); 378 iph = ipv6_hdr(skb); 379 380 nexthdr = *skb_mac_header(skb); 381 *skb_mac_header(skb) = IPPROTO_ROUTING; 382 383 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 384 rt2->rt_hdr.nexthdr = nexthdr; 385 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 386 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 387 rt2->rt_hdr.segments_left = 1; 388 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 389 390 WARN_ON(rt2->rt_hdr.hdrlen != 2); 391 392 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 393 spin_lock_bh(&x->lock); 394 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 395 spin_unlock_bh(&x->lock); 396 397 return 0; 398 } 399 400 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 401 u8 **nexthdr) 402 { 403 u16 offset = sizeof(struct ipv6hdr); 404 struct ipv6_opt_hdr *exthdr = 405 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 406 const unsigned char *nh = skb_network_header(skb); 407 unsigned int packet_len = skb_tail_pointer(skb) - 408 skb_network_header(skb); 409 int found_rhdr = 0; 410 411 *nexthdr = &ipv6_hdr(skb)->nexthdr; 412 413 while (offset + 1 <= packet_len) { 414 415 switch (**nexthdr) { 416 case NEXTHDR_HOP: 417 break; 418 case NEXTHDR_ROUTING: 419 if (offset + 3 <= packet_len) { 420 struct ipv6_rt_hdr *rt; 421 rt = (struct ipv6_rt_hdr *)(nh + offset); 422 if (rt->type != 0) 423 return offset; 424 } 425 found_rhdr = 1; 426 break; 427 case NEXTHDR_DEST: 428 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 429 return offset; 430 431 if (found_rhdr) 432 return offset; 433 434 break; 435 default: 436 return offset; 437 } 438 439 offset += ipv6_optlen(exthdr); 440 *nexthdr = &exthdr->nexthdr; 441 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 442 } 443 444 return offset; 445 } 446 447 static int mip6_rthdr_init_state(struct xfrm_state *x) 448 { 449 if (x->id.spi) { 450 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 451 return -EINVAL; 452 } 453 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 454 pr_info("%s: state's mode is not %u: %u\n", 455 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 456 return -EINVAL; 457 } 458 459 x->props.header_len = sizeof(struct rt2_hdr); 460 461 return 0; 462 } 463 464 /* 465 * Do nothing about destroying since it has no specific operation for routing 466 * header type 2 unlike IPsec protocols. 467 */ 468 static void mip6_rthdr_destroy(struct xfrm_state *x) 469 { 470 } 471 472 static const struct xfrm_type mip6_rthdr_type = { 473 .description = "MIP6RT", 474 .owner = THIS_MODULE, 475 .proto = IPPROTO_ROUTING, 476 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 477 .init_state = mip6_rthdr_init_state, 478 .destructor = mip6_rthdr_destroy, 479 .input = mip6_rthdr_input, 480 .output = mip6_rthdr_output, 481 .hdr_offset = mip6_rthdr_offset, 482 }; 483 484 static int __init mip6_init(void) 485 { 486 pr_info("Mobile IPv6\n"); 487 488 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 489 pr_info("%s: can't add xfrm type(destopt)\n", __func__); 490 goto mip6_destopt_xfrm_fail; 491 } 492 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 493 pr_info("%s: can't add xfrm type(rthdr)\n", __func__); 494 goto mip6_rthdr_xfrm_fail; 495 } 496 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 497 pr_info("%s: can't add rawv6 mh filter\n", __func__); 498 goto mip6_rawv6_mh_fail; 499 } 500 501 502 return 0; 503 504 mip6_rawv6_mh_fail: 505 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 506 mip6_rthdr_xfrm_fail: 507 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 508 mip6_destopt_xfrm_fail: 509 return -EAGAIN; 510 } 511 512 static void __exit mip6_fini(void) 513 { 514 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 515 pr_info("%s: can't remove rawv6 mh filter\n", __func__); 516 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 517 pr_info("%s: can't remove xfrm type(rthdr)\n", __func__); 518 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 519 pr_info("%s: can't remove xfrm type(destopt)\n", __func__); 520 } 521 522 module_init(mip6_init); 523 module_exit(mip6_fini); 524 525 MODULE_LICENSE("GPL"); 526 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 527 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 528