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 #include <linux/module.h> 26 #include <linux/skbuff.h> 27 #include <linux/time.h> 28 #include <linux/ipv6.h> 29 #include <linux/icmpv6.h> 30 #include <net/sock.h> 31 #include <net/ipv6.h> 32 #include <net/ip6_checksum.h> 33 #include <net/rawv6.h> 34 #include <net/xfrm.h> 35 #include <net/mip6.h> 36 37 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 38 { 39 return (n - len + 16) & 0x7; 40 } 41 42 static inline void *mip6_padn(__u8 *data, __u8 padlen) 43 { 44 if (!data) 45 return NULL; 46 if (padlen == 1) { 47 data[0] = IPV6_TLV_PAD0; 48 } else if (padlen > 1) { 49 data[0] = IPV6_TLV_PADN; 50 data[1] = padlen - 2; 51 if (padlen > 2) 52 memset(data+2, 0, data[1]); 53 } 54 return data + padlen; 55 } 56 57 static inline void mip6_param_prob(struct sk_buff *skb, u8 code, int pos) 58 { 59 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos); 60 } 61 62 static int mip6_mh_len(int type) 63 { 64 int len = 0; 65 66 switch (type) { 67 case IP6_MH_TYPE_BRR: 68 len = 0; 69 break; 70 case IP6_MH_TYPE_HOTI: 71 case IP6_MH_TYPE_COTI: 72 case IP6_MH_TYPE_BU: 73 case IP6_MH_TYPE_BACK: 74 len = 1; 75 break; 76 case IP6_MH_TYPE_HOT: 77 case IP6_MH_TYPE_COT: 78 case IP6_MH_TYPE_BERROR: 79 len = 2; 80 break; 81 } 82 return len; 83 } 84 85 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 86 { 87 struct ip6_mh *mh; 88 89 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) || 90 !pskb_may_pull(skb, (skb_transport_offset(skb) + 91 ((skb_transport_header(skb)[1] + 1) << 3)))) 92 return -1; 93 94 mh = (struct ip6_mh *)skb_transport_header(skb); 95 96 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 97 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 98 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); 99 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) - 100 skb_network_header(skb))); 101 return -1; 102 } 103 104 if (mh->ip6mh_proto != IPPROTO_NONE) { 105 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", 106 mh->ip6mh_proto); 107 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) - 108 skb_network_header(skb))); 109 return -1; 110 } 111 112 return 0; 113 } 114 115 struct mip6_report_rate_limiter { 116 spinlock_t lock; 117 struct timeval stamp; 118 int iif; 119 struct in6_addr src; 120 struct in6_addr dst; 121 }; 122 123 static struct mip6_report_rate_limiter mip6_report_rl = { 124 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 125 }; 126 127 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 128 { 129 struct ipv6hdr *iph = ipv6_hdr(skb); 130 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 131 int err = destopt->nexthdr; 132 133 spin_lock(&x->lock); 134 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 135 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 136 err = -ENOENT; 137 spin_unlock(&x->lock); 138 139 return err; 140 } 141 142 /* Destination Option Header is inserted. 143 * IP Header's src address is replaced with Home Address Option in 144 * Destination Option Header. 145 */ 146 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 147 { 148 struct ipv6hdr *iph; 149 struct ipv6_destopt_hdr *dstopt; 150 struct ipv6_destopt_hao *hao; 151 u8 nexthdr; 152 int len; 153 154 skb_push(skb, -skb_network_offset(skb)); 155 iph = ipv6_hdr(skb); 156 157 nexthdr = *skb_mac_header(skb); 158 *skb_mac_header(skb) = IPPROTO_DSTOPTS; 159 160 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 161 dstopt->nexthdr = nexthdr; 162 163 hao = mip6_padn((char *)(dstopt + 1), 164 calc_padlen(sizeof(*dstopt), 6)); 165 166 hao->type = IPV6_TLV_HAO; 167 BUILD_BUG_ON(sizeof(*hao) != 18); 168 hao->length = sizeof(*hao) - 2; 169 170 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 171 172 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 173 spin_lock_bh(&x->lock); 174 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 175 spin_unlock_bh(&x->lock); 176 177 WARN_ON(len != x->props.header_len); 178 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 179 180 return 0; 181 } 182 183 static inline int mip6_report_rl_allow(struct timeval *stamp, 184 struct in6_addr *dst, 185 struct in6_addr *src, int iif) 186 { 187 int allow = 0; 188 189 spin_lock_bh(&mip6_report_rl.lock); 190 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || 191 mip6_report_rl.stamp.tv_usec != stamp->tv_usec || 192 mip6_report_rl.iif != iif || 193 !ipv6_addr_equal(&mip6_report_rl.src, src) || 194 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 195 mip6_report_rl.stamp.tv_sec = stamp->tv_sec; 196 mip6_report_rl.stamp.tv_usec = stamp->tv_usec; 197 mip6_report_rl.iif = iif; 198 ipv6_addr_copy(&mip6_report_rl.src, src); 199 ipv6_addr_copy(&mip6_report_rl.dst, dst); 200 allow = 1; 201 } 202 spin_unlock_bh(&mip6_report_rl.lock); 203 return allow; 204 } 205 206 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, 207 const struct flowi *fl) 208 { 209 struct net *net = xs_net(x); 210 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 211 const struct flowi6 *fl6 = &fl->u.ip6; 212 struct ipv6_destopt_hao *hao = NULL; 213 struct xfrm_selector sel; 214 int offset; 215 struct timeval stamp; 216 int err = 0; 217 218 if (unlikely(fl6->flowi6_proto == IPPROTO_MH && 219 fl6->fl6_mh_type <= IP6_MH_TYPE_MAX)) 220 goto out; 221 222 if (likely(opt->dsthao)) { 223 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 224 if (likely(offset >= 0)) 225 hao = (struct ipv6_destopt_hao *) 226 (skb_network_header(skb) + offset); 227 } 228 229 skb_get_timestamp(skb, &stamp); 230 231 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 232 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 233 opt->iif)) 234 goto out; 235 236 memset(&sel, 0, sizeof(sel)); 237 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 238 sizeof(sel.daddr)); 239 sel.prefixlen_d = 128; 240 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 241 sizeof(sel.saddr)); 242 sel.prefixlen_s = 128; 243 sel.family = AF_INET6; 244 sel.proto = fl6->flowi6_proto; 245 sel.dport = xfrm_flowi_dport(fl, &fl6->uli); 246 if (sel.dport) 247 sel.dport_mask = htons(~0); 248 sel.sport = xfrm_flowi_sport(fl, &fl6->uli); 249 if (sel.sport) 250 sel.sport_mask = htons(~0); 251 sel.ifindex = fl6->flowi6_oif; 252 253 err = km_report(net, IPPROTO_DSTOPTS, &sel, 254 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 255 256 out: 257 return err; 258 } 259 260 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 261 u8 **nexthdr) 262 { 263 u16 offset = sizeof(struct ipv6hdr); 264 struct ipv6_opt_hdr *exthdr = 265 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 266 const unsigned char *nh = skb_network_header(skb); 267 unsigned int packet_len = skb->tail - skb->network_header; 268 int found_rhdr = 0; 269 270 *nexthdr = &ipv6_hdr(skb)->nexthdr; 271 272 while (offset + 1 <= packet_len) { 273 274 switch (**nexthdr) { 275 case NEXTHDR_HOP: 276 break; 277 case NEXTHDR_ROUTING: 278 found_rhdr = 1; 279 break; 280 case NEXTHDR_DEST: 281 /* 282 * HAO MUST NOT appear more than once. 283 * XXX: It is better to try to find by the end of 284 * XXX: packet if HAO exists. 285 */ 286 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 287 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 288 return offset; 289 } 290 291 if (found_rhdr) 292 return offset; 293 294 break; 295 default: 296 return offset; 297 } 298 299 offset += ipv6_optlen(exthdr); 300 *nexthdr = &exthdr->nexthdr; 301 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 302 } 303 304 return offset; 305 } 306 307 static int mip6_destopt_init_state(struct xfrm_state *x) 308 { 309 if (x->id.spi) { 310 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 311 x->id.spi); 312 return -EINVAL; 313 } 314 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 315 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 316 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 317 return -EINVAL; 318 } 319 320 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 321 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 322 sizeof(struct ipv6_destopt_hao); 323 WARN_ON(x->props.header_len != 24); 324 325 return 0; 326 } 327 328 /* 329 * Do nothing about destroying since it has no specific operation for 330 * destination options header unlike IPsec protocols. 331 */ 332 static void mip6_destopt_destroy(struct xfrm_state *x) 333 { 334 } 335 336 static const struct xfrm_type mip6_destopt_type = 337 { 338 .description = "MIP6DESTOPT", 339 .owner = THIS_MODULE, 340 .proto = IPPROTO_DSTOPTS, 341 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 342 .init_state = mip6_destopt_init_state, 343 .destructor = mip6_destopt_destroy, 344 .input = mip6_destopt_input, 345 .output = mip6_destopt_output, 346 .reject = mip6_destopt_reject, 347 .hdr_offset = mip6_destopt_offset, 348 }; 349 350 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 351 { 352 struct ipv6hdr *iph = ipv6_hdr(skb); 353 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 354 int err = rt2->rt_hdr.nexthdr; 355 356 spin_lock(&x->lock); 357 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) && 358 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 359 err = -ENOENT; 360 spin_unlock(&x->lock); 361 362 return err; 363 } 364 365 /* Routing Header type 2 is inserted. 366 * IP Header's dst address is replaced with Routing Header's Home Address. 367 */ 368 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 369 { 370 struct ipv6hdr *iph; 371 struct rt2_hdr *rt2; 372 u8 nexthdr; 373 374 skb_push(skb, -skb_network_offset(skb)); 375 iph = ipv6_hdr(skb); 376 377 nexthdr = *skb_mac_header(skb); 378 *skb_mac_header(skb) = IPPROTO_ROUTING; 379 380 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 381 rt2->rt_hdr.nexthdr = nexthdr; 382 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 383 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 384 rt2->rt_hdr.segments_left = 1; 385 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 386 387 WARN_ON(rt2->rt_hdr.hdrlen != 2); 388 389 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 390 spin_lock_bh(&x->lock); 391 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 392 spin_unlock_bh(&x->lock); 393 394 return 0; 395 } 396 397 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 398 u8 **nexthdr) 399 { 400 u16 offset = sizeof(struct ipv6hdr); 401 struct ipv6_opt_hdr *exthdr = 402 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 403 const unsigned char *nh = skb_network_header(skb); 404 unsigned int packet_len = skb->tail - skb->network_header; 405 int found_rhdr = 0; 406 407 *nexthdr = &ipv6_hdr(skb)->nexthdr; 408 409 while (offset + 1 <= packet_len) { 410 411 switch (**nexthdr) { 412 case NEXTHDR_HOP: 413 break; 414 case NEXTHDR_ROUTING: 415 if (offset + 3 <= packet_len) { 416 struct ipv6_rt_hdr *rt; 417 rt = (struct ipv6_rt_hdr *)(nh + offset); 418 if (rt->type != 0) 419 return offset; 420 } 421 found_rhdr = 1; 422 break; 423 case NEXTHDR_DEST: 424 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 425 return offset; 426 427 if (found_rhdr) 428 return offset; 429 430 break; 431 default: 432 return offset; 433 } 434 435 offset += ipv6_optlen(exthdr); 436 *nexthdr = &exthdr->nexthdr; 437 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 438 } 439 440 return offset; 441 } 442 443 static int mip6_rthdr_init_state(struct xfrm_state *x) 444 { 445 if (x->id.spi) { 446 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 447 x->id.spi); 448 return -EINVAL; 449 } 450 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 451 printk(KERN_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 printk(KERN_INFO "Mobile IPv6\n"); 485 486 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 487 printk(KERN_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 printk(KERN_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 printk(KERN_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 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__); 514 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 515 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__); 516 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 517 printk(KERN_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