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 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 101 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); 102 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_hdrlen) + 103 skb_network_header_len(skb)); 104 return -1; 105 } 106 107 if (mh->ip6mh_proto != IPPROTO_NONE) { 108 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", 109 mh->ip6mh_proto); 110 mip6_param_prob(skb, 0, offsetof(struct ip6_mh, ip6mh_proto) + 111 skb_network_header_len(skb)); 112 return -1; 113 } 114 115 return 0; 116 } 117 118 struct mip6_report_rate_limiter { 119 spinlock_t lock; 120 struct timeval stamp; 121 int iif; 122 struct in6_addr src; 123 struct in6_addr dst; 124 }; 125 126 static struct mip6_report_rate_limiter mip6_report_rl = { 127 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 128 }; 129 130 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 131 { 132 const struct ipv6hdr *iph = ipv6_hdr(skb); 133 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 134 int err = destopt->nexthdr; 135 136 spin_lock(&x->lock); 137 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 138 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 139 err = -ENOENT; 140 spin_unlock(&x->lock); 141 142 return err; 143 } 144 145 /* Destination Option Header is inserted. 146 * IP Header's src address is replaced with Home Address Option in 147 * Destination Option Header. 148 */ 149 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 150 { 151 struct ipv6hdr *iph; 152 struct ipv6_destopt_hdr *dstopt; 153 struct ipv6_destopt_hao *hao; 154 u8 nexthdr; 155 int len; 156 157 skb_push(skb, -skb_network_offset(skb)); 158 iph = ipv6_hdr(skb); 159 160 nexthdr = *skb_mac_header(skb); 161 *skb_mac_header(skb) = IPPROTO_DSTOPTS; 162 163 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 164 dstopt->nexthdr = nexthdr; 165 166 hao = mip6_padn((char *)(dstopt + 1), 167 calc_padlen(sizeof(*dstopt), 6)); 168 169 hao->type = IPV6_TLV_HAO; 170 BUILD_BUG_ON(sizeof(*hao) != 18); 171 hao->length = sizeof(*hao) - 2; 172 173 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 174 175 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 176 spin_lock_bh(&x->lock); 177 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 178 spin_unlock_bh(&x->lock); 179 180 WARN_ON(len != x->props.header_len); 181 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 182 183 return 0; 184 } 185 186 static inline int mip6_report_rl_allow(struct timeval *stamp, 187 const struct in6_addr *dst, 188 const struct in6_addr *src, int iif) 189 { 190 int allow = 0; 191 192 spin_lock_bh(&mip6_report_rl.lock); 193 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || 194 mip6_report_rl.stamp.tv_usec != stamp->tv_usec || 195 mip6_report_rl.iif != iif || 196 !ipv6_addr_equal(&mip6_report_rl.src, src) || 197 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 198 mip6_report_rl.stamp.tv_sec = stamp->tv_sec; 199 mip6_report_rl.stamp.tv_usec = stamp->tv_usec; 200 mip6_report_rl.iif = iif; 201 mip6_report_rl.src = *src; 202 mip6_report_rl.dst = *dst; 203 allow = 1; 204 } 205 spin_unlock_bh(&mip6_report_rl.lock); 206 return allow; 207 } 208 209 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, 210 const struct flowi *fl) 211 { 212 struct net *net = xs_net(x); 213 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 214 const struct flowi6 *fl6 = &fl->u.ip6; 215 struct ipv6_destopt_hao *hao = NULL; 216 struct xfrm_selector sel; 217 int offset; 218 struct timeval stamp; 219 int err = 0; 220 221 if (unlikely(fl6->flowi6_proto == IPPROTO_MH && 222 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX)) 223 goto out; 224 225 if (likely(opt->dsthao)) { 226 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 227 if (likely(offset >= 0)) 228 hao = (struct ipv6_destopt_hao *) 229 (skb_network_header(skb) + offset); 230 } 231 232 skb_get_timestamp(skb, &stamp); 233 234 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 235 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 236 opt->iif)) 237 goto out; 238 239 memset(&sel, 0, sizeof(sel)); 240 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 241 sizeof(sel.daddr)); 242 sel.prefixlen_d = 128; 243 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 244 sizeof(sel.saddr)); 245 sel.prefixlen_s = 128; 246 sel.family = AF_INET6; 247 sel.proto = fl6->flowi6_proto; 248 sel.dport = xfrm_flowi_dport(fl, &fl6->uli); 249 if (sel.dport) 250 sel.dport_mask = htons(~0); 251 sel.sport = xfrm_flowi_sport(fl, &fl6->uli); 252 if (sel.sport) 253 sel.sport_mask = htons(~0); 254 sel.ifindex = fl6->flowi6_oif; 255 256 err = km_report(net, IPPROTO_DSTOPTS, &sel, 257 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 258 259 out: 260 return err; 261 } 262 263 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 264 u8 **nexthdr) 265 { 266 u16 offset = sizeof(struct ipv6hdr); 267 struct ipv6_opt_hdr *exthdr = 268 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 269 const unsigned char *nh = skb_network_header(skb); 270 unsigned int packet_len = skb_tail_pointer(skb) - 271 skb_network_header(skb); 272 int found_rhdr = 0; 273 274 *nexthdr = &ipv6_hdr(skb)->nexthdr; 275 276 while (offset + 1 <= packet_len) { 277 278 switch (**nexthdr) { 279 case NEXTHDR_HOP: 280 break; 281 case NEXTHDR_ROUTING: 282 found_rhdr = 1; 283 break; 284 case NEXTHDR_DEST: 285 /* 286 * HAO MUST NOT appear more than once. 287 * XXX: It is better to try to find by the end of 288 * XXX: packet if HAO exists. 289 */ 290 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 291 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 292 return offset; 293 } 294 295 if (found_rhdr) 296 return offset; 297 298 break; 299 default: 300 return offset; 301 } 302 303 offset += ipv6_optlen(exthdr); 304 *nexthdr = &exthdr->nexthdr; 305 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 306 } 307 308 return offset; 309 } 310 311 static int mip6_destopt_init_state(struct xfrm_state *x) 312 { 313 if (x->id.spi) { 314 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 315 return -EINVAL; 316 } 317 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 318 pr_info("%s: state's mode is not %u: %u\n", 319 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 320 return -EINVAL; 321 } 322 323 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 324 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 325 sizeof(struct ipv6_destopt_hao); 326 WARN_ON(x->props.header_len != 24); 327 328 return 0; 329 } 330 331 /* 332 * Do nothing about destroying since it has no specific operation for 333 * destination options header unlike IPsec protocols. 334 */ 335 static void mip6_destopt_destroy(struct xfrm_state *x) 336 { 337 } 338 339 static const struct xfrm_type mip6_destopt_type = 340 { 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 { 474 .description = "MIP6RT", 475 .owner = THIS_MODULE, 476 .proto = IPPROTO_ROUTING, 477 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 478 .init_state = mip6_rthdr_init_state, 479 .destructor = mip6_rthdr_destroy, 480 .input = mip6_rthdr_input, 481 .output = mip6_rthdr_output, 482 .hdr_offset = mip6_rthdr_offset, 483 }; 484 485 static int __init mip6_init(void) 486 { 487 pr_info("Mobile IPv6\n"); 488 489 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 490 pr_info("%s: can't add xfrm type(destopt)\n", __func__); 491 goto mip6_destopt_xfrm_fail; 492 } 493 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 494 pr_info("%s: can't add xfrm type(rthdr)\n", __func__); 495 goto mip6_rthdr_xfrm_fail; 496 } 497 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 498 pr_info("%s: can't add rawv6 mh filter\n", __func__); 499 goto mip6_rawv6_mh_fail; 500 } 501 502 503 return 0; 504 505 mip6_rawv6_mh_fail: 506 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 507 mip6_rthdr_xfrm_fail: 508 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 509 mip6_destopt_xfrm_fail: 510 return -EAGAIN; 511 } 512 513 static void __exit mip6_fini(void) 514 { 515 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 516 pr_info("%s: can't remove rawv6 mh filter\n", __func__); 517 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 518 pr_info("%s: can't remove xfrm type(rthdr)\n", __func__); 519 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 520 pr_info("%s: can't remove xfrm type(destopt)\n", __func__); 521 } 522 523 module_init(mip6_init); 524 module_exit(mip6_fini); 525 526 MODULE_LICENSE("GPL"); 527 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 528 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 529