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 *mh; 90 91 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) || 92 !pskb_may_pull(skb, (skb_transport_offset(skb) + 93 ((skb_transport_header(skb)[1] + 1) << 3)))) 94 return -1; 95 96 mh = (struct ip6_mh *)skb_transport_header(skb); 97 98 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 99 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 100 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); 101 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) - 102 skb_network_header(skb))); 103 return -1; 104 } 105 106 if (mh->ip6mh_proto != IPPROTO_NONE) { 107 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", 108 mh->ip6mh_proto); 109 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) - 110 skb_network_header(skb))); 111 return -1; 112 } 113 114 return 0; 115 } 116 117 struct mip6_report_rate_limiter { 118 spinlock_t lock; 119 struct timeval stamp; 120 int iif; 121 struct in6_addr src; 122 struct in6_addr dst; 123 }; 124 125 static struct mip6_report_rate_limiter mip6_report_rl = { 126 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 127 }; 128 129 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 130 { 131 const struct ipv6hdr *iph = ipv6_hdr(skb); 132 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 133 int err = destopt->nexthdr; 134 135 spin_lock(&x->lock); 136 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 137 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 138 err = -ENOENT; 139 spin_unlock(&x->lock); 140 141 return err; 142 } 143 144 /* Destination Option Header is inserted. 145 * IP Header's src address is replaced with Home Address Option in 146 * Destination Option Header. 147 */ 148 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 149 { 150 struct ipv6hdr *iph; 151 struct ipv6_destopt_hdr *dstopt; 152 struct ipv6_destopt_hao *hao; 153 u8 nexthdr; 154 int len; 155 156 skb_push(skb, -skb_network_offset(skb)); 157 iph = ipv6_hdr(skb); 158 159 nexthdr = *skb_mac_header(skb); 160 *skb_mac_header(skb) = IPPROTO_DSTOPTS; 161 162 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 163 dstopt->nexthdr = nexthdr; 164 165 hao = mip6_padn((char *)(dstopt + 1), 166 calc_padlen(sizeof(*dstopt), 6)); 167 168 hao->type = IPV6_TLV_HAO; 169 BUILD_BUG_ON(sizeof(*hao) != 18); 170 hao->length = sizeof(*hao) - 2; 171 172 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 173 174 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 175 spin_lock_bh(&x->lock); 176 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 177 spin_unlock_bh(&x->lock); 178 179 WARN_ON(len != x->props.header_len); 180 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 181 182 return 0; 183 } 184 185 static inline int mip6_report_rl_allow(struct timeval *stamp, 186 const struct in6_addr *dst, 187 const struct in6_addr *src, int iif) 188 { 189 int allow = 0; 190 191 spin_lock_bh(&mip6_report_rl.lock); 192 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || 193 mip6_report_rl.stamp.tv_usec != stamp->tv_usec || 194 mip6_report_rl.iif != iif || 195 !ipv6_addr_equal(&mip6_report_rl.src, src) || 196 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 197 mip6_report_rl.stamp.tv_sec = stamp->tv_sec; 198 mip6_report_rl.stamp.tv_usec = stamp->tv_usec; 199 mip6_report_rl.iif = iif; 200 mip6_report_rl.src = *src; 201 mip6_report_rl.dst = *dst; 202 allow = 1; 203 } 204 spin_unlock_bh(&mip6_report_rl.lock); 205 return allow; 206 } 207 208 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, 209 const struct flowi *fl) 210 { 211 struct net *net = xs_net(x); 212 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 213 const struct flowi6 *fl6 = &fl->u.ip6; 214 struct ipv6_destopt_hao *hao = NULL; 215 struct xfrm_selector sel; 216 int offset; 217 struct timeval stamp; 218 int err = 0; 219 220 if (unlikely(fl6->flowi6_proto == IPPROTO_MH && 221 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX)) 222 goto out; 223 224 if (likely(opt->dsthao)) { 225 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 226 if (likely(offset >= 0)) 227 hao = (struct ipv6_destopt_hao *) 228 (skb_network_header(skb) + offset); 229 } 230 231 skb_get_timestamp(skb, &stamp); 232 233 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 234 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 235 opt->iif)) 236 goto out; 237 238 memset(&sel, 0, sizeof(sel)); 239 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 240 sizeof(sel.daddr)); 241 sel.prefixlen_d = 128; 242 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 243 sizeof(sel.saddr)); 244 sel.prefixlen_s = 128; 245 sel.family = AF_INET6; 246 sel.proto = fl6->flowi6_proto; 247 sel.dport = xfrm_flowi_dport(fl, &fl6->uli); 248 if (sel.dport) 249 sel.dport_mask = htons(~0); 250 sel.sport = xfrm_flowi_sport(fl, &fl6->uli); 251 if (sel.sport) 252 sel.sport_mask = htons(~0); 253 sel.ifindex = fl6->flowi6_oif; 254 255 err = km_report(net, IPPROTO_DSTOPTS, &sel, 256 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 257 258 out: 259 return err; 260 } 261 262 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 263 u8 **nexthdr) 264 { 265 u16 offset = sizeof(struct ipv6hdr); 266 struct ipv6_opt_hdr *exthdr = 267 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 268 const unsigned char *nh = skb_network_header(skb); 269 unsigned int packet_len = skb->tail - skb->network_header; 270 int found_rhdr = 0; 271 272 *nexthdr = &ipv6_hdr(skb)->nexthdr; 273 274 while (offset + 1 <= packet_len) { 275 276 switch (**nexthdr) { 277 case NEXTHDR_HOP: 278 break; 279 case NEXTHDR_ROUTING: 280 found_rhdr = 1; 281 break; 282 case NEXTHDR_DEST: 283 /* 284 * HAO MUST NOT appear more than once. 285 * XXX: It is better to try to find by the end of 286 * XXX: packet if HAO exists. 287 */ 288 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 289 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 290 return offset; 291 } 292 293 if (found_rhdr) 294 return offset; 295 296 break; 297 default: 298 return offset; 299 } 300 301 offset += ipv6_optlen(exthdr); 302 *nexthdr = &exthdr->nexthdr; 303 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 304 } 305 306 return offset; 307 } 308 309 static int mip6_destopt_init_state(struct xfrm_state *x) 310 { 311 if (x->id.spi) { 312 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 313 return -EINVAL; 314 } 315 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 316 pr_info("%s: state's mode is not %u: %u\n", 317 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 318 return -EINVAL; 319 } 320 321 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 322 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 323 sizeof(struct ipv6_destopt_hao); 324 WARN_ON(x->props.header_len != 24); 325 326 return 0; 327 } 328 329 /* 330 * Do nothing about destroying since it has no specific operation for 331 * destination options header unlike IPsec protocols. 332 */ 333 static void mip6_destopt_destroy(struct xfrm_state *x) 334 { 335 } 336 337 static const struct xfrm_type mip6_destopt_type = 338 { 339 .description = "MIP6DESTOPT", 340 .owner = THIS_MODULE, 341 .proto = IPPROTO_DSTOPTS, 342 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 343 .init_state = mip6_destopt_init_state, 344 .destructor = mip6_destopt_destroy, 345 .input = mip6_destopt_input, 346 .output = mip6_destopt_output, 347 .reject = mip6_destopt_reject, 348 .hdr_offset = mip6_destopt_offset, 349 }; 350 351 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 352 { 353 const struct ipv6hdr *iph = ipv6_hdr(skb); 354 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 355 int err = rt2->rt_hdr.nexthdr; 356 357 spin_lock(&x->lock); 358 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) && 359 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 360 err = -ENOENT; 361 spin_unlock(&x->lock); 362 363 return err; 364 } 365 366 /* Routing Header type 2 is inserted. 367 * IP Header's dst address is replaced with Routing Header's Home Address. 368 */ 369 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 370 { 371 struct ipv6hdr *iph; 372 struct rt2_hdr *rt2; 373 u8 nexthdr; 374 375 skb_push(skb, -skb_network_offset(skb)); 376 iph = ipv6_hdr(skb); 377 378 nexthdr = *skb_mac_header(skb); 379 *skb_mac_header(skb) = IPPROTO_ROUTING; 380 381 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 382 rt2->rt_hdr.nexthdr = nexthdr; 383 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 384 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 385 rt2->rt_hdr.segments_left = 1; 386 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 387 388 WARN_ON(rt2->rt_hdr.hdrlen != 2); 389 390 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 391 spin_lock_bh(&x->lock); 392 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 393 spin_unlock_bh(&x->lock); 394 395 return 0; 396 } 397 398 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 399 u8 **nexthdr) 400 { 401 u16 offset = sizeof(struct ipv6hdr); 402 struct ipv6_opt_hdr *exthdr = 403 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 404 const unsigned char *nh = skb_network_header(skb); 405 unsigned int packet_len = skb->tail - skb->network_header; 406 int found_rhdr = 0; 407 408 *nexthdr = &ipv6_hdr(skb)->nexthdr; 409 410 while (offset + 1 <= packet_len) { 411 412 switch (**nexthdr) { 413 case NEXTHDR_HOP: 414 break; 415 case NEXTHDR_ROUTING: 416 if (offset + 3 <= packet_len) { 417 struct ipv6_rt_hdr *rt; 418 rt = (struct ipv6_rt_hdr *)(nh + offset); 419 if (rt->type != 0) 420 return offset; 421 } 422 found_rhdr = 1; 423 break; 424 case NEXTHDR_DEST: 425 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 426 return offset; 427 428 if (found_rhdr) 429 return offset; 430 431 break; 432 default: 433 return offset; 434 } 435 436 offset += ipv6_optlen(exthdr); 437 *nexthdr = &exthdr->nexthdr; 438 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 439 } 440 441 return offset; 442 } 443 444 static int mip6_rthdr_init_state(struct xfrm_state *x) 445 { 446 if (x->id.spi) { 447 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 448 return -EINVAL; 449 } 450 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 451 pr_info("%s: state's mode is not %u: %u\n", 452 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 453 return -EINVAL; 454 } 455 456 x->props.header_len = sizeof(struct rt2_hdr); 457 458 return 0; 459 } 460 461 /* 462 * Do nothing about destroying since it has no specific operation for routing 463 * header type 2 unlike IPsec protocols. 464 */ 465 static void mip6_rthdr_destroy(struct xfrm_state *x) 466 { 467 } 468 469 static const struct xfrm_type mip6_rthdr_type = 470 { 471 .description = "MIP6RT", 472 .owner = THIS_MODULE, 473 .proto = IPPROTO_ROUTING, 474 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 475 .init_state = mip6_rthdr_init_state, 476 .destructor = mip6_rthdr_destroy, 477 .input = mip6_rthdr_input, 478 .output = mip6_rthdr_output, 479 .hdr_offset = mip6_rthdr_offset, 480 }; 481 482 static int __init mip6_init(void) 483 { 484 pr_info("Mobile IPv6\n"); 485 486 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 487 pr_info("%s: can't add xfrm type(destopt)\n", __func__); 488 goto mip6_destopt_xfrm_fail; 489 } 490 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 491 pr_info("%s: can't add xfrm type(rthdr)\n", __func__); 492 goto mip6_rthdr_xfrm_fail; 493 } 494 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 495 pr_info("%s: can't add rawv6 mh filter\n", __func__); 496 goto mip6_rawv6_mh_fail; 497 } 498 499 500 return 0; 501 502 mip6_rawv6_mh_fail: 503 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 504 mip6_rthdr_xfrm_fail: 505 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 506 mip6_destopt_xfrm_fail: 507 return -EAGAIN; 508 } 509 510 static void __exit mip6_fini(void) 511 { 512 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 513 pr_info("%s: can't remove rawv6 mh filter\n", __func__); 514 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 515 pr_info("%s: can't remove xfrm type(rthdr)\n", __func__); 516 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 517 pr_info("%s: can't remove xfrm type(destopt)\n", __func__); 518 } 519 520 module_init(mip6_init); 521 module_exit(mip6_fini); 522 523 MODULE_LICENSE("GPL"); 524 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 525 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 526