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, int code, int pos) 58 { 59 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev); 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, struct flowi *fl) 207 { 208 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 209 struct ipv6_destopt_hao *hao = NULL; 210 struct xfrm_selector sel; 211 int offset; 212 struct timeval stamp; 213 int err = 0; 214 215 if (unlikely(fl->proto == IPPROTO_MH && 216 fl->fl_mh_type <= IP6_MH_TYPE_MAX)) 217 goto out; 218 219 if (likely(opt->dsthao)) { 220 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 221 if (likely(offset >= 0)) 222 hao = (struct ipv6_destopt_hao *) 223 (skb_network_header(skb) + offset); 224 } 225 226 skb_get_timestamp(skb, &stamp); 227 228 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 229 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 230 opt->iif)) 231 goto out; 232 233 memset(&sel, 0, sizeof(sel)); 234 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 235 sizeof(sel.daddr)); 236 sel.prefixlen_d = 128; 237 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 238 sizeof(sel.saddr)); 239 sel.prefixlen_s = 128; 240 sel.family = AF_INET6; 241 sel.proto = fl->proto; 242 sel.dport = xfrm_flowi_dport(fl); 243 if (sel.dport) 244 sel.dport_mask = htons(~0); 245 sel.sport = xfrm_flowi_sport(fl); 246 if (sel.sport) 247 sel.sport_mask = htons(~0); 248 sel.ifindex = fl->oif; 249 250 err = km_report(IPPROTO_DSTOPTS, &sel, 251 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 252 253 out: 254 return err; 255 } 256 257 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 258 u8 **nexthdr) 259 { 260 u16 offset = sizeof(struct ipv6hdr); 261 struct ipv6_opt_hdr *exthdr = 262 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 263 const unsigned char *nh = skb_network_header(skb); 264 unsigned int packet_len = skb->tail - skb->network_header; 265 int found_rhdr = 0; 266 267 *nexthdr = &ipv6_hdr(skb)->nexthdr; 268 269 while (offset + 1 <= packet_len) { 270 271 switch (**nexthdr) { 272 case NEXTHDR_HOP: 273 break; 274 case NEXTHDR_ROUTING: 275 found_rhdr = 1; 276 break; 277 case NEXTHDR_DEST: 278 /* 279 * HAO MUST NOT appear more than once. 280 * XXX: It is better to try to find by the end of 281 * XXX: packet if HAO exists. 282 */ 283 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 284 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 285 return offset; 286 } 287 288 if (found_rhdr) 289 return offset; 290 291 break; 292 default: 293 return offset; 294 } 295 296 offset += ipv6_optlen(exthdr); 297 *nexthdr = &exthdr->nexthdr; 298 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 299 } 300 301 return offset; 302 } 303 304 static int mip6_destopt_init_state(struct xfrm_state *x) 305 { 306 if (x->id.spi) { 307 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 308 x->id.spi); 309 return -EINVAL; 310 } 311 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 312 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 313 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 314 return -EINVAL; 315 } 316 317 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 318 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 319 sizeof(struct ipv6_destopt_hao); 320 WARN_ON(x->props.header_len != 24); 321 322 return 0; 323 } 324 325 /* 326 * Do nothing about destroying since it has no specific operation for 327 * destination options header unlike IPsec protocols. 328 */ 329 static void mip6_destopt_destroy(struct xfrm_state *x) 330 { 331 } 332 333 static const struct xfrm_type mip6_destopt_type = 334 { 335 .description = "MIP6DESTOPT", 336 .owner = THIS_MODULE, 337 .proto = IPPROTO_DSTOPTS, 338 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 339 .init_state = mip6_destopt_init_state, 340 .destructor = mip6_destopt_destroy, 341 .input = mip6_destopt_input, 342 .output = mip6_destopt_output, 343 .reject = mip6_destopt_reject, 344 .hdr_offset = mip6_destopt_offset, 345 }; 346 347 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 348 { 349 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 350 int err = rt2->rt_hdr.nexthdr; 351 352 spin_lock(&x->lock); 353 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) && 354 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 355 err = -ENOENT; 356 spin_unlock(&x->lock); 357 358 return err; 359 } 360 361 /* Routing Header type 2 is inserted. 362 * IP Header's dst address is replaced with Routing Header's Home Address. 363 */ 364 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 365 { 366 struct ipv6hdr *iph; 367 struct rt2_hdr *rt2; 368 u8 nexthdr; 369 370 skb_push(skb, -skb_network_offset(skb)); 371 iph = ipv6_hdr(skb); 372 373 nexthdr = *skb_mac_header(skb); 374 *skb_mac_header(skb) = IPPROTO_ROUTING; 375 376 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 377 rt2->rt_hdr.nexthdr = nexthdr; 378 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 379 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 380 rt2->rt_hdr.segments_left = 1; 381 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 382 383 WARN_ON(rt2->rt_hdr.hdrlen != 2); 384 385 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 386 spin_lock_bh(&x->lock); 387 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 388 spin_unlock_bh(&x->lock); 389 390 return 0; 391 } 392 393 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 394 u8 **nexthdr) 395 { 396 u16 offset = sizeof(struct ipv6hdr); 397 struct ipv6_opt_hdr *exthdr = 398 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 399 const unsigned char *nh = skb_network_header(skb); 400 unsigned int packet_len = skb->tail - skb->network_header; 401 int found_rhdr = 0; 402 403 *nexthdr = &ipv6_hdr(skb)->nexthdr; 404 405 while (offset + 1 <= packet_len) { 406 407 switch (**nexthdr) { 408 case NEXTHDR_HOP: 409 break; 410 case NEXTHDR_ROUTING: 411 if (offset + 3 <= packet_len) { 412 struct ipv6_rt_hdr *rt; 413 rt = (struct ipv6_rt_hdr *)(nh + offset); 414 if (rt->type != 0) 415 return offset; 416 } 417 found_rhdr = 1; 418 break; 419 case NEXTHDR_DEST: 420 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 421 return offset; 422 423 if (found_rhdr) 424 return offset; 425 426 break; 427 default: 428 return offset; 429 } 430 431 offset += ipv6_optlen(exthdr); 432 *nexthdr = &exthdr->nexthdr; 433 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 434 } 435 436 return offset; 437 } 438 439 static int mip6_rthdr_init_state(struct xfrm_state *x) 440 { 441 if (x->id.spi) { 442 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 443 x->id.spi); 444 return -EINVAL; 445 } 446 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 447 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 448 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 449 return -EINVAL; 450 } 451 452 x->props.header_len = sizeof(struct rt2_hdr); 453 454 return 0; 455 } 456 457 /* 458 * Do nothing about destroying since it has no specific operation for routing 459 * header type 2 unlike IPsec protocols. 460 */ 461 static void mip6_rthdr_destroy(struct xfrm_state *x) 462 { 463 } 464 465 static const struct xfrm_type mip6_rthdr_type = 466 { 467 .description = "MIP6RT", 468 .owner = THIS_MODULE, 469 .proto = IPPROTO_ROUTING, 470 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 471 .init_state = mip6_rthdr_init_state, 472 .destructor = mip6_rthdr_destroy, 473 .input = mip6_rthdr_input, 474 .output = mip6_rthdr_output, 475 .hdr_offset = mip6_rthdr_offset, 476 }; 477 478 static int __init mip6_init(void) 479 { 480 printk(KERN_INFO "Mobile IPv6\n"); 481 482 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 483 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __func__); 484 goto mip6_destopt_xfrm_fail; 485 } 486 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 487 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__); 488 goto mip6_rthdr_xfrm_fail; 489 } 490 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 491 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__); 492 goto mip6_rawv6_mh_fail; 493 } 494 495 496 return 0; 497 498 mip6_rawv6_mh_fail: 499 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 500 mip6_rthdr_xfrm_fail: 501 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 502 mip6_destopt_xfrm_fail: 503 return -EAGAIN; 504 } 505 506 static void __exit mip6_fini(void) 507 { 508 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 509 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__); 510 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 511 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__); 512 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 513 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__); 514 } 515 516 module_init(mip6_init); 517 module_exit(mip6_fini); 518 519 MODULE_LICENSE("GPL"); 520 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 521 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 522