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 ktime_t 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(ktime_t 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 (!ktime_equal(mip6_report_rl.stamp, stamp) || 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 = stamp; 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 ktime_t 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 stamp = skb_get_ktime(skb); 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_pointer(skb) - 270 skb_network_header(skb); 271 int found_rhdr = 0; 272 273 *nexthdr = &ipv6_hdr(skb)->nexthdr; 274 275 while (offset + 1 <= packet_len) { 276 277 switch (**nexthdr) { 278 case NEXTHDR_HOP: 279 break; 280 case NEXTHDR_ROUTING: 281 found_rhdr = 1; 282 break; 283 case NEXTHDR_DEST: 284 /* 285 * HAO MUST NOT appear more than once. 286 * XXX: It is better to try to find by the end of 287 * XXX: packet if HAO exists. 288 */ 289 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 290 net_dbg_ratelimited("mip6: hao exists already, override\n"); 291 return offset; 292 } 293 294 if (found_rhdr) 295 return offset; 296 297 break; 298 default: 299 return offset; 300 } 301 302 offset += ipv6_optlen(exthdr); 303 *nexthdr = &exthdr->nexthdr; 304 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 305 } 306 307 return offset; 308 } 309 310 static int mip6_destopt_init_state(struct xfrm_state *x) 311 { 312 if (x->id.spi) { 313 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 314 return -EINVAL; 315 } 316 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 317 pr_info("%s: state's mode is not %u: %u\n", 318 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 319 return -EINVAL; 320 } 321 322 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 323 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 324 sizeof(struct ipv6_destopt_hao); 325 WARN_ON(x->props.header_len != 24); 326 327 return 0; 328 } 329 330 /* 331 * Do nothing about destroying since it has no specific operation for 332 * destination options header unlike IPsec protocols. 333 */ 334 static void mip6_destopt_destroy(struct xfrm_state *x) 335 { 336 } 337 338 static const struct xfrm_type mip6_destopt_type = { 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_pointer(skb) - 406 skb_network_header(skb); 407 int found_rhdr = 0; 408 409 *nexthdr = &ipv6_hdr(skb)->nexthdr; 410 411 while (offset + 1 <= packet_len) { 412 413 switch (**nexthdr) { 414 case NEXTHDR_HOP: 415 break; 416 case NEXTHDR_ROUTING: 417 if (offset + 3 <= packet_len) { 418 struct ipv6_rt_hdr *rt; 419 rt = (struct ipv6_rt_hdr *)(nh + offset); 420 if (rt->type != 0) 421 return offset; 422 } 423 found_rhdr = 1; 424 break; 425 case NEXTHDR_DEST: 426 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 427 return offset; 428 429 if (found_rhdr) 430 return offset; 431 432 break; 433 default: 434 return offset; 435 } 436 437 offset += ipv6_optlen(exthdr); 438 *nexthdr = &exthdr->nexthdr; 439 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 440 } 441 442 return offset; 443 } 444 445 static int mip6_rthdr_init_state(struct xfrm_state *x) 446 { 447 if (x->id.spi) { 448 pr_info("%s: spi is not 0: %u\n", __func__, x->id.spi); 449 return -EINVAL; 450 } 451 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 452 pr_info("%s: state's mode is not %u: %u\n", 453 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 454 return -EINVAL; 455 } 456 457 x->props.header_len = sizeof(struct rt2_hdr); 458 459 return 0; 460 } 461 462 /* 463 * Do nothing about destroying since it has no specific operation for routing 464 * header type 2 unlike IPsec protocols. 465 */ 466 static void mip6_rthdr_destroy(struct xfrm_state *x) 467 { 468 } 469 470 static const struct xfrm_type mip6_rthdr_type = { 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