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, struct flowi *fl) 207 { 208 struct net *net = xs_net(x); 209 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 210 struct ipv6_destopt_hao *hao = NULL; 211 struct xfrm_selector sel; 212 int offset; 213 struct timeval stamp; 214 int err = 0; 215 216 if (unlikely(fl->proto == IPPROTO_MH && 217 fl->fl_mh_type <= IP6_MH_TYPE_MAX)) 218 goto out; 219 220 if (likely(opt->dsthao)) { 221 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 222 if (likely(offset >= 0)) 223 hao = (struct ipv6_destopt_hao *) 224 (skb_network_header(skb) + offset); 225 } 226 227 skb_get_timestamp(skb, &stamp); 228 229 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 230 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 231 opt->iif)) 232 goto out; 233 234 memset(&sel, 0, sizeof(sel)); 235 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 236 sizeof(sel.daddr)); 237 sel.prefixlen_d = 128; 238 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 239 sizeof(sel.saddr)); 240 sel.prefixlen_s = 128; 241 sel.family = AF_INET6; 242 sel.proto = fl->proto; 243 sel.dport = xfrm_flowi_dport(fl); 244 if (sel.dport) 245 sel.dport_mask = htons(~0); 246 sel.sport = xfrm_flowi_sport(fl); 247 if (sel.sport) 248 sel.sport_mask = htons(~0); 249 sel.ifindex = fl->oif; 250 251 err = km_report(net, IPPROTO_DSTOPTS, &sel, 252 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 253 254 out: 255 return err; 256 } 257 258 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 259 u8 **nexthdr) 260 { 261 u16 offset = sizeof(struct ipv6hdr); 262 struct ipv6_opt_hdr *exthdr = 263 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 264 const unsigned char *nh = skb_network_header(skb); 265 unsigned int packet_len = skb->tail - skb->network_header; 266 int found_rhdr = 0; 267 268 *nexthdr = &ipv6_hdr(skb)->nexthdr; 269 270 while (offset + 1 <= packet_len) { 271 272 switch (**nexthdr) { 273 case NEXTHDR_HOP: 274 break; 275 case NEXTHDR_ROUTING: 276 found_rhdr = 1; 277 break; 278 case NEXTHDR_DEST: 279 /* 280 * HAO MUST NOT appear more than once. 281 * XXX: It is better to try to find by the end of 282 * XXX: packet if HAO exists. 283 */ 284 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 285 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 286 return offset; 287 } 288 289 if (found_rhdr) 290 return offset; 291 292 break; 293 default: 294 return offset; 295 } 296 297 offset += ipv6_optlen(exthdr); 298 *nexthdr = &exthdr->nexthdr; 299 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 300 } 301 302 return offset; 303 } 304 305 static int mip6_destopt_init_state(struct xfrm_state *x) 306 { 307 if (x->id.spi) { 308 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 309 x->id.spi); 310 return -EINVAL; 311 } 312 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 313 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 314 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 315 return -EINVAL; 316 } 317 318 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 319 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 320 sizeof(struct ipv6_destopt_hao); 321 WARN_ON(x->props.header_len != 24); 322 323 return 0; 324 } 325 326 /* 327 * Do nothing about destroying since it has no specific operation for 328 * destination options header unlike IPsec protocols. 329 */ 330 static void mip6_destopt_destroy(struct xfrm_state *x) 331 { 332 } 333 334 static const struct xfrm_type mip6_destopt_type = 335 { 336 .description = "MIP6DESTOPT", 337 .owner = THIS_MODULE, 338 .proto = IPPROTO_DSTOPTS, 339 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_LOCAL_COADDR, 340 .init_state = mip6_destopt_init_state, 341 .destructor = mip6_destopt_destroy, 342 .input = mip6_destopt_input, 343 .output = mip6_destopt_output, 344 .reject = mip6_destopt_reject, 345 .hdr_offset = mip6_destopt_offset, 346 }; 347 348 static int mip6_rthdr_input(struct xfrm_state *x, struct sk_buff *skb) 349 { 350 struct ipv6hdr *iph = ipv6_hdr(skb); 351 struct rt2_hdr *rt2 = (struct rt2_hdr *)skb->data; 352 int err = rt2->rt_hdr.nexthdr; 353 354 spin_lock(&x->lock); 355 if (!ipv6_addr_equal(&iph->daddr, (struct in6_addr *)x->coaddr) && 356 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 357 err = -ENOENT; 358 spin_unlock(&x->lock); 359 360 return err; 361 } 362 363 /* Routing Header type 2 is inserted. 364 * IP Header's dst address is replaced with Routing Header's Home Address. 365 */ 366 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 367 { 368 struct ipv6hdr *iph; 369 struct rt2_hdr *rt2; 370 u8 nexthdr; 371 372 skb_push(skb, -skb_network_offset(skb)); 373 iph = ipv6_hdr(skb); 374 375 nexthdr = *skb_mac_header(skb); 376 *skb_mac_header(skb) = IPPROTO_ROUTING; 377 378 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 379 rt2->rt_hdr.nexthdr = nexthdr; 380 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 381 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 382 rt2->rt_hdr.segments_left = 1; 383 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 384 385 WARN_ON(rt2->rt_hdr.hdrlen != 2); 386 387 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 388 spin_lock_bh(&x->lock); 389 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 390 spin_unlock_bh(&x->lock); 391 392 return 0; 393 } 394 395 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 396 u8 **nexthdr) 397 { 398 u16 offset = sizeof(struct ipv6hdr); 399 struct ipv6_opt_hdr *exthdr = 400 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 401 const unsigned char *nh = skb_network_header(skb); 402 unsigned int packet_len = skb->tail - skb->network_header; 403 int found_rhdr = 0; 404 405 *nexthdr = &ipv6_hdr(skb)->nexthdr; 406 407 while (offset + 1 <= packet_len) { 408 409 switch (**nexthdr) { 410 case NEXTHDR_HOP: 411 break; 412 case NEXTHDR_ROUTING: 413 if (offset + 3 <= packet_len) { 414 struct ipv6_rt_hdr *rt; 415 rt = (struct ipv6_rt_hdr *)(nh + offset); 416 if (rt->type != 0) 417 return offset; 418 } 419 found_rhdr = 1; 420 break; 421 case NEXTHDR_DEST: 422 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 423 return offset; 424 425 if (found_rhdr) 426 return offset; 427 428 break; 429 default: 430 return offset; 431 } 432 433 offset += ipv6_optlen(exthdr); 434 *nexthdr = &exthdr->nexthdr; 435 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 436 } 437 438 return offset; 439 } 440 441 static int mip6_rthdr_init_state(struct xfrm_state *x) 442 { 443 if (x->id.spi) { 444 printk(KERN_INFO "%s: spi is not 0: %u\n", __func__, 445 x->id.spi); 446 return -EINVAL; 447 } 448 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 449 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 450 __func__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 451 return -EINVAL; 452 } 453 454 x->props.header_len = sizeof(struct rt2_hdr); 455 456 return 0; 457 } 458 459 /* 460 * Do nothing about destroying since it has no specific operation for routing 461 * header type 2 unlike IPsec protocols. 462 */ 463 static void mip6_rthdr_destroy(struct xfrm_state *x) 464 { 465 } 466 467 static const struct xfrm_type mip6_rthdr_type = 468 { 469 .description = "MIP6RT", 470 .owner = THIS_MODULE, 471 .proto = IPPROTO_ROUTING, 472 .flags = XFRM_TYPE_NON_FRAGMENT | XFRM_TYPE_REMOTE_COADDR, 473 .init_state = mip6_rthdr_init_state, 474 .destructor = mip6_rthdr_destroy, 475 .input = mip6_rthdr_input, 476 .output = mip6_rthdr_output, 477 .hdr_offset = mip6_rthdr_offset, 478 }; 479 480 static int __init mip6_init(void) 481 { 482 printk(KERN_INFO "Mobile IPv6\n"); 483 484 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 485 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __func__); 486 goto mip6_destopt_xfrm_fail; 487 } 488 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 489 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __func__); 490 goto mip6_rthdr_xfrm_fail; 491 } 492 if (rawv6_mh_filter_register(mip6_mh_filter) < 0) { 493 printk(KERN_INFO "%s: can't add rawv6 mh filter\n", __func__); 494 goto mip6_rawv6_mh_fail; 495 } 496 497 498 return 0; 499 500 mip6_rawv6_mh_fail: 501 xfrm_unregister_type(&mip6_rthdr_type, AF_INET6); 502 mip6_rthdr_xfrm_fail: 503 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 504 mip6_destopt_xfrm_fail: 505 return -EAGAIN; 506 } 507 508 static void __exit mip6_fini(void) 509 { 510 if (rawv6_mh_filter_unregister(mip6_mh_filter) < 0) 511 printk(KERN_INFO "%s: can't remove rawv6 mh filter\n", __func__); 512 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 513 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __func__); 514 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 515 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __func__); 516 } 517 518 module_init(mip6_init); 519 module_exit(mip6_fini); 520 521 MODULE_LICENSE("GPL"); 522 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_DSTOPTS); 523 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ROUTING); 524