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 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 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 spin_lock_bh(&x->lock); 176 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 177 spin_unlock_bh(&x->lock); 178 179 BUG_TRAP(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 struct in6_addr *dst, 187 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 ipv6_addr_copy(&mip6_report_rl.src, src); 201 ipv6_addr_copy(&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, struct flowi *fl) 209 { 210 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 211 struct ipv6_destopt_hao *hao = NULL; 212 struct xfrm_selector sel; 213 int offset; 214 struct timeval stamp; 215 int err = 0; 216 217 if (unlikely(fl->proto == IPPROTO_MH && 218 fl->fl_mh_type <= IP6_MH_TYPE_MAX)) 219 goto out; 220 221 if (likely(opt->dsthao)) { 222 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 223 if (likely(offset >= 0)) 224 hao = (struct ipv6_destopt_hao *) 225 (skb_network_header(skb) + offset); 226 } 227 228 skb_get_timestamp(skb, &stamp); 229 230 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 231 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 232 opt->iif)) 233 goto out; 234 235 memset(&sel, 0, sizeof(sel)); 236 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 237 sizeof(sel.daddr)); 238 sel.prefixlen_d = 128; 239 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 240 sizeof(sel.saddr)); 241 sel.prefixlen_s = 128; 242 sel.family = AF_INET6; 243 sel.proto = fl->proto; 244 sel.dport = xfrm_flowi_dport(fl); 245 if (sel.dport) 246 sel.dport_mask = htons(~0); 247 sel.sport = xfrm_flowi_sport(fl); 248 if (sel.sport) 249 sel.sport_mask = htons(~0); 250 sel.ifindex = fl->oif; 251 252 err = km_report(IPPROTO_DSTOPTS, &sel, 253 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 254 255 out: 256 return err; 257 } 258 259 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 260 u8 **nexthdr) 261 { 262 u16 offset = sizeof(struct ipv6hdr); 263 struct ipv6_opt_hdr *exthdr = 264 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 265 const unsigned char *nh = skb_network_header(skb); 266 unsigned int packet_len = skb->tail - skb->network_header; 267 int found_rhdr = 0; 268 269 *nexthdr = &ipv6_hdr(skb)->nexthdr; 270 271 while (offset + 1 <= packet_len) { 272 273 switch (**nexthdr) { 274 case NEXTHDR_HOP: 275 break; 276 case NEXTHDR_ROUTING: 277 found_rhdr = 1; 278 break; 279 case NEXTHDR_DEST: 280 /* 281 * HAO MUST NOT appear more than once. 282 * XXX: It is better to try to find by the end of 283 * XXX: packet if HAO exists. 284 */ 285 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 286 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 287 return offset; 288 } 289 290 if (found_rhdr) 291 return offset; 292 293 break; 294 default: 295 return offset; 296 } 297 298 offset += ipv6_optlen(exthdr); 299 *nexthdr = &exthdr->nexthdr; 300 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 301 } 302 303 return offset; 304 } 305 306 static int mip6_destopt_init_state(struct xfrm_state *x) 307 { 308 if (x->id.spi) { 309 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, 310 x->id.spi); 311 return -EINVAL; 312 } 313 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 314 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 315 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 316 return -EINVAL; 317 } 318 319 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 320 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 321 sizeof(struct ipv6_destopt_hao); 322 BUG_TRAP(x->props.header_len == 24); 323 324 return 0; 325 } 326 327 /* 328 * Do nothing about destroying since it has no specific operation for 329 * destination options header unlike IPsec protocols. 330 */ 331 static void mip6_destopt_destroy(struct xfrm_state *x) 332 { 333 } 334 335 static struct xfrm_type mip6_destopt_type = 336 { 337 .description = "MIP6DESTOPT", 338 .owner = THIS_MODULE, 339 .proto = IPPROTO_DSTOPTS, 340 .flags = XFRM_TYPE_NON_FRAGMENT, 341 .init_state = mip6_destopt_init_state, 342 .destructor = mip6_destopt_destroy, 343 .input = mip6_destopt_input, 344 .output = mip6_destopt_output, 345 .reject = mip6_destopt_reject, 346 .hdr_offset = mip6_destopt_offset, 347 .local_addr = mip6_xfrm_addr, 348 }; 349 350 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 351 { 352 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 353 354 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) && 355 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 356 return -ENOENT; 357 358 return rt2->rt_hdr.nexthdr; 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 BUG_TRAP(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", __FUNCTION__, 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 __FUNCTION__, 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 struct xfrm_type mip6_rthdr_type = 466 { 467 .description = "MIP6RT", 468 .owner = THIS_MODULE, 469 .proto = IPPROTO_ROUTING, 470 .flags = XFRM_TYPE_NON_FRAGMENT, 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 .remote_addr = mip6_xfrm_addr, 477 }; 478 479 static int __init mip6_init(void) 480 { 481 printk(KERN_INFO "Mobile IPv6\n"); 482 483 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 484 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__); 485 goto mip6_destopt_xfrm_fail; 486 } 487 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 488 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__); 489 goto mip6_rthdr_xfrm_fail; 490 } 491 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 492 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __FUNCTION__); 493 goto mip6_rawv6_mh_fail; 494 } 495 496 497 return 0; 498 499 mip6_rawv6_mh_fail: 500 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 501 mip6_rthdr_xfrm_fail: 502 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 503 mip6_destopt_xfrm_fail: 504 return -EAGAIN; 505 } 506 507 static void __exit mip6_fini(void) 508 { 509 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 510 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __FUNCTION__); 511 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 512 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__); 513 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 514 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__); 515 } 516 517 module_init(mip6_init); 518 module_exit(mip6_fini); 519 520 MODULE_LICENSE("GPL"); 521 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 522 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 523