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, write to the Free Software 17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 18 */ 19 /* 20 * Authors: 21 * Noriaki TAKAMIYA @USAGI 22 * Masahide NAKAMURA @USAGI 23 */ 24 25 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 26 27 #include <linux/module.h> 28 #include <linux/skbuff.h> 29 #include <linux/time.h> 30 #include <linux/ipv6.h> 31 #include <linux/icmpv6.h> 32 #include <net/sock.h> 33 #include <net/ipv6.h> 34 #include <net/ip6_checksum.h> 35 #include <net/rawv6.h> 36 #include <net/xfrm.h> 37 #include <net/mip6.h> 38 39 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 40 { 41 return (n - len + 16) & 0x7; 42 } 43 44 static inline void *mip6_padn(__u8 *data, __u8 padlen) 45 { 46 if (!data) 47 return NULL; 48 if (padlen == 1) { 49 data[0] = IPV6_TLV_PAD1; 50 } else if (padlen > 1) { 51 data[0] = IPV6_TLV_PADN; 52 data[1] = padlen - 2; 53 if (padlen > 2) 54 memset(data+2, 0, data[1]); 55 } 56 return data + padlen; 57 } 58 59 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos) 60 { 61 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); 62 } 63 64 static int mip6_mh_len(int type) 65 { 66 int len = 0; 67 68 switch (type) { 69 case IP6_MH_TYPE_BRR: 70 len = 0; 71 break; 72 case IP6_MH_TYPE_HOTI: 73 case IP6_MH_TYPE_COTI: 74 case IP6_MH_TYPE_BU: 75 case IP6_MH_TYPE_BACK: 76 len = 1; 77 break; 78 case IP6_MH_TYPE_HOT: 79 case IP6_MH_TYPE_COT: 80 case IP6_MH_TYPE_BERROR: 81 len = 2; 82 break; 83 } 84 return len; 85 } 86 87 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 88 { 89 struct ip6_mh _hdr; 90 const struct ip6_mh *mh; 91 92 mh = skb_header_pointer(skb, skb_transport_offset(skb), 93 sizeof(_hdr), &_hdr); 94 if (!mh) 95 return -1; 96 97 if (((mh->ip6mh_hdrlen + 1) << 3) > skb->len) 98 return -1; 99 100 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 101 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 102 mh->ip6mh_hdrlen, 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 LIMIT_NETDEBUG(KERN_DEBUG "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 - skb->network_header; 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 - skb->network_header; 408 int found_rhdr = 0; 409 410 *nexthdr = &ipv6_hdr(skb)->nexthdr; 411 412 while (offset + 1 <= packet_len) { 413 414 switch (**nexthdr) { 415 case NEXTHDR_HOP: 416 break; 417 case NEXTHDR_ROUTING: 418 if (offset + 3 <= packet_len) { 419 struct ipv6_rt_hdr *rt; 420 rt = (struct ipv6_rt_hdr *)(nh + offset); 421 if (rt->type != 0) 422 return offset; 423 } 424 found_rhdr = 1; 425 break; 426 case NEXTHDR_DEST: 427 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 428 return offset; 429 430 if (found_rhdr) 431 return offset; 432 433 break; 434 default: 435 return offset; 436 } 437 438 offset += ipv6_optlen(exthdr); 439 *nexthdr = &exthdr->nexthdr; 440 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 441 } 442 443 return offset; 444 } 445 446 static int mip6_rthdr_init_state(struct xfrm_state *x) 447 { 448 if (x->id.spi) { 449 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 450 return -EINVAL; 451 } 452 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 453 pr_info("%s: state's mode is not %u: %u\n", 454 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 455 return -EINVAL; 456 } 457 458 x->props.header_len = sizeof(struct rt2_hdr); 459 460 return 0; 461 } 462 463 /* 464 * Do nothing about destroying since it has no specific operation for routing 465 * header type 2 unlike IPsec protocols. 466 */ 467 static void mip6_rthdr_destroy(struct xfrm_state *x) 468 { 469 } 470 471 static const struct xfrm_type mip6_rthdr_type = 472 { 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