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 xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr) 38 { 39 return x->coaddr; 40 } 41 42 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 43 { 44 return (n - len + 16) & 0x7; 45 } 46 47 static inline void *mip6_padn(__u8 *data, __u8 padlen) 48 { 49 if (!data) 50 return NULL; 51 if (padlen == 1) { 52 data[0] = MIP6_OPT_PAD_1; 53 } else if (padlen > 1) { 54 data[0] = MIP6_OPT_PAD_N; 55 data[1] = padlen - 2; 56 if (padlen > 2) 57 memset(data+2, 0, data[1]); 58 } 59 return data + padlen; 60 } 61 62 static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos) 63 { 64 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev); 65 } 66 67 static int mip6_mh_len(int type) 68 { 69 int len = 0; 70 71 switch (type) { 72 case IP6_MH_TYPE_BRR: 73 len = 0; 74 break; 75 case IP6_MH_TYPE_HOTI: 76 case IP6_MH_TYPE_COTI: 77 case IP6_MH_TYPE_BU: 78 case IP6_MH_TYPE_BACK: 79 len = 1; 80 break; 81 case IP6_MH_TYPE_HOT: 82 case IP6_MH_TYPE_COT: 83 case IP6_MH_TYPE_BERROR: 84 len = 2; 85 break; 86 } 87 return len; 88 } 89 90 static int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 91 { 92 struct ip6_mh *mh; 93 94 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) || 95 !pskb_may_pull(skb, (skb_transport_offset(skb) + 96 ((skb_transport_header(skb)[1] + 1) << 3)))) 97 return -1; 98 99 mh = (struct ip6_mh *)skb_transport_header(skb); 100 101 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 102 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 103 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); 104 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) - 105 skb_network_header(skb))); 106 return -1; 107 } 108 109 if (mh->ip6mh_proto != IPPROTO_NONE) { 110 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", 111 mh->ip6mh_proto); 112 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) - 113 skb_network_header(skb))); 114 return -1; 115 } 116 117 return 0; 118 } 119 120 struct mip6_report_rate_limiter { 121 spinlock_t lock; 122 struct timeval stamp; 123 int iif; 124 struct in6_addr src; 125 struct in6_addr dst; 126 }; 127 128 static struct mip6_report_rate_limiter mip6_report_rl = { 129 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 130 }; 131 132 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 133 { 134 struct ipv6hdr *iph = ipv6_hdr(skb); 135 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 136 137 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 138 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 139 return -ENOENT; 140 141 return destopt->nexthdr; 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 iph = (struct ipv6hdr *)skb->data; 157 iph->payload_len = htons(skb->len - sizeof(*iph)); 158 159 nexthdr = *skb_network_header(skb); 160 *skb_network_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 hao->length = sizeof(*hao) - 2; 170 BUG_TRAP(hao->length == 16); 171 172 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 173 174 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 175 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 176 177 BUG_TRAP(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", __FUNCTION__, 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 __FUNCTION__, 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 BUG_TRAP(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 struct xfrm_type mip6_destopt_type = 334 { 335 .description = "MIP6DESTOPT", 336 .owner = THIS_MODULE, 337 .proto = IPPROTO_DSTOPTS, 338 .flags = XFRM_TYPE_NON_FRAGMENT, 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 .local_addr = mip6_xfrm_addr, 346 }; 347 348 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 349 { 350 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 351 352 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) && 353 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 354 return -ENOENT; 355 356 return rt2->rt_hdr.nexthdr; 357 } 358 359 /* Routing Header type 2 is inserted. 360 * IP Header's dst address is replaced with Routing Header's Home Address. 361 */ 362 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 363 { 364 struct ipv6hdr *iph; 365 struct rt2_hdr *rt2; 366 u8 nexthdr; 367 368 iph = (struct ipv6hdr *)skb->data; 369 iph->payload_len = htons(skb->len - sizeof(*iph)); 370 371 nexthdr = *skb_network_header(skb); 372 *skb_network_header(skb) = IPPROTO_ROUTING; 373 374 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 375 rt2->rt_hdr.nexthdr = nexthdr; 376 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 377 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 378 rt2->rt_hdr.segments_left = 1; 379 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 380 381 BUG_TRAP(rt2->rt_hdr.hdrlen == 2); 382 383 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 384 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 385 386 return 0; 387 } 388 389 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 390 u8 **nexthdr) 391 { 392 u16 offset = sizeof(struct ipv6hdr); 393 struct ipv6_opt_hdr *exthdr = 394 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 395 const unsigned char *nh = skb_network_header(skb); 396 unsigned int packet_len = skb->tail - skb->network_header; 397 int found_rhdr = 0; 398 399 *nexthdr = &ipv6_hdr(skb)->nexthdr; 400 401 while (offset + 1 <= packet_len) { 402 403 switch (**nexthdr) { 404 case NEXTHDR_HOP: 405 break; 406 case NEXTHDR_ROUTING: 407 if (offset + 3 <= packet_len) { 408 struct ipv6_rt_hdr *rt; 409 rt = (struct ipv6_rt_hdr *)(nh + offset); 410 if (rt->type != 0) 411 return offset; 412 } 413 found_rhdr = 1; 414 break; 415 case NEXTHDR_DEST: 416 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 417 return offset; 418 419 if (found_rhdr) 420 return offset; 421 422 break; 423 default: 424 return offset; 425 } 426 427 offset += ipv6_optlen(exthdr); 428 *nexthdr = &exthdr->nexthdr; 429 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 430 } 431 432 return offset; 433 } 434 435 static int mip6_rthdr_init_state(struct xfrm_state *x) 436 { 437 if (x->id.spi) { 438 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, 439 x->id.spi); 440 return -EINVAL; 441 } 442 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 443 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 444 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 445 return -EINVAL; 446 } 447 448 x->props.header_len = sizeof(struct rt2_hdr); 449 450 return 0; 451 } 452 453 /* 454 * Do nothing about destroying since it has no specific operation for routing 455 * header type 2 unlike IPsec protocols. 456 */ 457 static void mip6_rthdr_destroy(struct xfrm_state *x) 458 { 459 } 460 461 static struct xfrm_type mip6_rthdr_type = 462 { 463 .description = "MIP6RT", 464 .owner = THIS_MODULE, 465 .proto = IPPROTO_ROUTING, 466 .flags = XFRM_TYPE_NON_FRAGMENT, 467 .init_state = mip6_rthdr_init_state, 468 .destructor = mip6_rthdr_destroy, 469 .input = mip6_rthdr_input, 470 .output = mip6_rthdr_output, 471 .hdr_offset = mip6_rthdr_offset, 472 .remote_addr = mip6_xfrm_addr, 473 }; 474 475 static int __init mip6_init(void) 476 { 477 printk(KERN_INFO "Mobile IPv6\n"); 478 479 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 480 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__); 481 goto mip6_destopt_xfrm_fail; 482 } 483 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 484 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__); 485 goto mip6_rthdr_xfrm_fail; 486 } 487 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 488 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __FUNCTION__); 489 goto mip6_rawv6_mh_fail; 490 } 491 492 493 return 0; 494 495 mip6_rawv6_mh_fail: 496 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 497 mip6_rthdr_xfrm_fail: 498 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 499 mip6_destopt_xfrm_fail: 500 return -EAGAIN; 501 } 502 503 static void __exit mip6_fini(void) 504 { 505 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 506 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __FUNCTION__); 507 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 508 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__); 509 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 510 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__); 511 } 512 513 module_init(mip6_init); 514 module_exit(mip6_fini); 515 516 MODULE_LICENSE("GPL"); 517 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 518 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 519