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/xfrm.h> 34 #include <net/mip6.h> 35 36 static xfrm_address_t *mip6_xfrm_addr(struct xfrm_state *x, xfrm_address_t *addr) 37 { 38 return x->coaddr; 39 } 40 41 static inline unsigned int calc_padlen(unsigned int len, unsigned int n) 42 { 43 return (n - len + 16) & 0x7; 44 } 45 46 static inline void *mip6_padn(__u8 *data, __u8 padlen) 47 { 48 if (!data) 49 return NULL; 50 if (padlen == 1) { 51 data[0] = MIP6_OPT_PAD_1; 52 } else if (padlen > 1) { 53 data[0] = MIP6_OPT_PAD_N; 54 data[1] = padlen - 2; 55 if (padlen > 2) 56 memset(data+2, 0, data[1]); 57 } 58 return data + padlen; 59 } 60 61 static inline void mip6_param_prob(struct sk_buff *skb, int code, int pos) 62 { 63 icmpv6_send(skb, ICMPV6_PARAMPROB, code, pos, skb->dev); 64 } 65 66 static int mip6_mh_len(int type) 67 { 68 int len = 0; 69 70 switch (type) { 71 case IP6_MH_TYPE_BRR: 72 len = 0; 73 break; 74 case IP6_MH_TYPE_HOTI: 75 case IP6_MH_TYPE_COTI: 76 case IP6_MH_TYPE_BU: 77 case IP6_MH_TYPE_BACK: 78 len = 1; 79 break; 80 case IP6_MH_TYPE_HOT: 81 case IP6_MH_TYPE_COT: 82 case IP6_MH_TYPE_BERROR: 83 len = 2; 84 break; 85 } 86 return len; 87 } 88 89 int mip6_mh_filter(struct sock *sk, struct sk_buff *skb) 90 { 91 struct ip6_mh *mh; 92 93 if (!pskb_may_pull(skb, (skb_transport_offset(skb)) + 8) || 94 !pskb_may_pull(skb, (skb_transport_offset(skb) + 95 ((skb_transport_header(skb)[1] + 1) << 3)))) 96 return -1; 97 98 mh = (struct ip6_mh *)skb_transport_header(skb); 99 100 if (mh->ip6mh_hdrlen < mip6_mh_len(mh->ip6mh_type)) { 101 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH message too short: %d vs >=%d\n", 102 mh->ip6mh_hdrlen, mip6_mh_len(mh->ip6mh_type)); 103 mip6_param_prob(skb, 0, ((&mh->ip6mh_hdrlen) - 104 skb_network_header(skb))); 105 return -1; 106 } 107 108 if (mh->ip6mh_proto != IPPROTO_NONE) { 109 LIMIT_NETDEBUG(KERN_DEBUG "mip6: MH invalid payload proto = %d\n", 110 mh->ip6mh_proto); 111 mip6_param_prob(skb, 0, ((&mh->ip6mh_proto) - 112 skb_network_header(skb))); 113 return -1; 114 } 115 116 return 0; 117 } 118 119 struct mip6_report_rate_limiter { 120 spinlock_t lock; 121 struct timeval stamp; 122 int iif; 123 struct in6_addr src; 124 struct in6_addr dst; 125 }; 126 127 static struct mip6_report_rate_limiter mip6_report_rl = { 128 .lock = __SPIN_LOCK_UNLOCKED(mip6_report_rl.lock) 129 }; 130 131 static int mip6_destopt_input(struct xfrm_state *x, struct sk_buff *skb) 132 { 133 struct ipv6hdr *iph = ipv6_hdr(skb); 134 struct ipv6_destopt_hdr *destopt = (struct ipv6_destopt_hdr *)skb->data; 135 136 if (!ipv6_addr_equal(&iph->saddr, (struct in6_addr *)x->coaddr) && 137 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 138 return -ENOENT; 139 140 return destopt->nexthdr; 141 } 142 143 /* Destination Option Header is inserted. 144 * IP Header's src address is replaced with Home Address Option in 145 * Destination Option Header. 146 */ 147 static int mip6_destopt_output(struct xfrm_state *x, struct sk_buff *skb) 148 { 149 struct ipv6hdr *iph; 150 struct ipv6_destopt_hdr *dstopt; 151 struct ipv6_destopt_hao *hao; 152 u8 nexthdr; 153 int len; 154 155 iph = (struct ipv6hdr *)skb->data; 156 iph->payload_len = htons(skb->len - sizeof(*iph)); 157 158 nexthdr = *skb_network_header(skb); 159 *skb_network_header(skb) = IPPROTO_DSTOPTS; 160 161 dstopt = (struct ipv6_destopt_hdr *)skb_transport_header(skb); 162 dstopt->nexthdr = nexthdr; 163 164 hao = mip6_padn((char *)(dstopt + 1), 165 calc_padlen(sizeof(*dstopt), 6)); 166 167 hao->type = IPV6_TLV_HAO; 168 hao->length = sizeof(*hao) - 2; 169 BUG_TRAP(hao->length == 16); 170 171 len = ((char *)hao - (char *)dstopt) + sizeof(*hao); 172 173 memcpy(&hao->addr, &iph->saddr, sizeof(hao->addr)); 174 memcpy(&iph->saddr, x->coaddr, sizeof(iph->saddr)); 175 176 BUG_TRAP(len == x->props.header_len); 177 dstopt->hdrlen = (x->props.header_len >> 3) - 1; 178 179 return 0; 180 } 181 182 static inline int mip6_report_rl_allow(struct timeval *stamp, 183 struct in6_addr *dst, 184 struct in6_addr *src, int iif) 185 { 186 int allow = 0; 187 188 spin_lock_bh(&mip6_report_rl.lock); 189 if (mip6_report_rl.stamp.tv_sec != stamp->tv_sec || 190 mip6_report_rl.stamp.tv_usec != stamp->tv_usec || 191 mip6_report_rl.iif != iif || 192 !ipv6_addr_equal(&mip6_report_rl.src, src) || 193 !ipv6_addr_equal(&mip6_report_rl.dst, dst)) { 194 mip6_report_rl.stamp.tv_sec = stamp->tv_sec; 195 mip6_report_rl.stamp.tv_usec = stamp->tv_usec; 196 mip6_report_rl.iif = iif; 197 ipv6_addr_copy(&mip6_report_rl.src, src); 198 ipv6_addr_copy(&mip6_report_rl.dst, dst); 199 allow = 1; 200 } 201 spin_unlock_bh(&mip6_report_rl.lock); 202 return allow; 203 } 204 205 static int mip6_destopt_reject(struct xfrm_state *x, struct sk_buff *skb, struct flowi *fl) 206 { 207 struct inet6_skb_parm *opt = (struct inet6_skb_parm *)skb->cb; 208 struct ipv6_destopt_hao *hao = NULL; 209 struct xfrm_selector sel; 210 int offset; 211 struct timeval stamp; 212 int err = 0; 213 214 if (unlikely(fl->proto == IPPROTO_MH && 215 fl->fl_mh_type <= IP6_MH_TYPE_MAX)) 216 goto out; 217 218 if (likely(opt->dsthao)) { 219 offset = ipv6_find_tlv(skb, opt->dsthao, IPV6_TLV_HAO); 220 if (likely(offset >= 0)) 221 hao = (struct ipv6_destopt_hao *) 222 (skb_network_header(skb) + offset); 223 } 224 225 skb_get_timestamp(skb, &stamp); 226 227 if (!mip6_report_rl_allow(&stamp, &ipv6_hdr(skb)->daddr, 228 hao ? &hao->addr : &ipv6_hdr(skb)->saddr, 229 opt->iif)) 230 goto out; 231 232 memset(&sel, 0, sizeof(sel)); 233 memcpy(&sel.daddr, (xfrm_address_t *)&ipv6_hdr(skb)->daddr, 234 sizeof(sel.daddr)); 235 sel.prefixlen_d = 128; 236 memcpy(&sel.saddr, (xfrm_address_t *)&ipv6_hdr(skb)->saddr, 237 sizeof(sel.saddr)); 238 sel.prefixlen_s = 128; 239 sel.family = AF_INET6; 240 sel.proto = fl->proto; 241 sel.dport = xfrm_flowi_dport(fl); 242 if (sel.dport) 243 sel.dport_mask = htons(~0); 244 sel.sport = xfrm_flowi_sport(fl); 245 if (sel.sport) 246 sel.sport_mask = htons(~0); 247 sel.ifindex = fl->oif; 248 249 err = km_report(IPPROTO_DSTOPTS, &sel, 250 (hao ? (xfrm_address_t *)&hao->addr : NULL)); 251 252 out: 253 return err; 254 } 255 256 static int mip6_destopt_offset(struct xfrm_state *x, struct sk_buff *skb, 257 u8 **nexthdr) 258 { 259 u16 offset = sizeof(struct ipv6hdr); 260 struct ipv6_opt_hdr *exthdr = 261 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 262 const unsigned char *nh = skb_network_header(skb); 263 unsigned int packet_len = skb->tail - skb->network_header; 264 int found_rhdr = 0; 265 266 *nexthdr = &ipv6_hdr(skb)->nexthdr; 267 268 while (offset + 1 <= packet_len) { 269 270 switch (**nexthdr) { 271 case NEXTHDR_HOP: 272 break; 273 case NEXTHDR_ROUTING: 274 found_rhdr = 1; 275 break; 276 case NEXTHDR_DEST: 277 /* 278 * HAO MUST NOT appear more than once. 279 * XXX: It is better to try to find by the end of 280 * XXX: packet if HAO exists. 281 */ 282 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) { 283 LIMIT_NETDEBUG(KERN_WARNING "mip6: hao exists already, override\n"); 284 return offset; 285 } 286 287 if (found_rhdr) 288 return offset; 289 290 break; 291 default: 292 return offset; 293 } 294 295 offset += ipv6_optlen(exthdr); 296 *nexthdr = &exthdr->nexthdr; 297 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 298 } 299 300 return offset; 301 } 302 303 static int mip6_destopt_init_state(struct xfrm_state *x) 304 { 305 if (x->id.spi) { 306 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, 307 x->id.spi); 308 return -EINVAL; 309 } 310 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 311 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 312 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 313 return -EINVAL; 314 } 315 316 x->props.header_len = sizeof(struct ipv6_destopt_hdr) + 317 calc_padlen(sizeof(struct ipv6_destopt_hdr), 6) + 318 sizeof(struct ipv6_destopt_hao); 319 BUG_TRAP(x->props.header_len == 24); 320 321 return 0; 322 } 323 324 /* 325 * Do nothing about destroying since it has no specific operation for 326 * destination options header unlike IPsec protocols. 327 */ 328 static void mip6_destopt_destroy(struct xfrm_state *x) 329 { 330 } 331 332 static struct xfrm_type mip6_destopt_type = 333 { 334 .description = "MIP6DESTOPT", 335 .owner = THIS_MODULE, 336 .proto = IPPROTO_DSTOPTS, 337 .flags = XFRM_TYPE_NON_FRAGMENT, 338 .init_state = mip6_destopt_init_state, 339 .destructor = mip6_destopt_destroy, 340 .input = mip6_destopt_input, 341 .output = mip6_destopt_output, 342 .reject = mip6_destopt_reject, 343 .hdr_offset = mip6_destopt_offset, 344 .local_addr = mip6_xfrm_addr, 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; 350 351 if (!ipv6_addr_equal(&rt2->addr, (struct in6_addr *)x->coaddr) && 352 !ipv6_addr_any((struct in6_addr *)x->coaddr)) 353 return -ENOENT; 354 355 return rt2->rt_hdr.nexthdr; 356 } 357 358 /* Routing Header type 2 is inserted. 359 * IP Header's dst address is replaced with Routing Header's Home Address. 360 */ 361 static int mip6_rthdr_output(struct xfrm_state *x, struct sk_buff *skb) 362 { 363 struct ipv6hdr *iph; 364 struct rt2_hdr *rt2; 365 u8 nexthdr; 366 367 iph = (struct ipv6hdr *)skb->data; 368 iph->payload_len = htons(skb->len - sizeof(*iph)); 369 370 nexthdr = *skb_network_header(skb); 371 *skb_network_header(skb) = IPPROTO_ROUTING; 372 373 rt2 = (struct rt2_hdr *)skb_transport_header(skb); 374 rt2->rt_hdr.nexthdr = nexthdr; 375 rt2->rt_hdr.hdrlen = (x->props.header_len >> 3) - 1; 376 rt2->rt_hdr.type = IPV6_SRCRT_TYPE_2; 377 rt2->rt_hdr.segments_left = 1; 378 memset(&rt2->reserved, 0, sizeof(rt2->reserved)); 379 380 BUG_TRAP(rt2->rt_hdr.hdrlen == 2); 381 382 memcpy(&rt2->addr, &iph->daddr, sizeof(rt2->addr)); 383 memcpy(&iph->daddr, x->coaddr, sizeof(iph->daddr)); 384 385 return 0; 386 } 387 388 static int mip6_rthdr_offset(struct xfrm_state *x, struct sk_buff *skb, 389 u8 **nexthdr) 390 { 391 u16 offset = sizeof(struct ipv6hdr); 392 struct ipv6_opt_hdr *exthdr = 393 (struct ipv6_opt_hdr *)(ipv6_hdr(skb) + 1); 394 const unsigned char *nh = skb_network_header(skb); 395 unsigned int packet_len = skb->tail - skb->network_header; 396 int found_rhdr = 0; 397 398 *nexthdr = &ipv6_hdr(skb)->nexthdr; 399 400 while (offset + 1 <= packet_len) { 401 402 switch (**nexthdr) { 403 case NEXTHDR_HOP: 404 break; 405 case NEXTHDR_ROUTING: 406 if (offset + 3 <= packet_len) { 407 struct ipv6_rt_hdr *rt; 408 rt = (struct ipv6_rt_hdr *)(nh + offset); 409 if (rt->type != 0) 410 return offset; 411 } 412 found_rhdr = 1; 413 break; 414 case NEXTHDR_DEST: 415 if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) 416 return offset; 417 418 if (found_rhdr) 419 return offset; 420 421 break; 422 default: 423 return offset; 424 } 425 426 offset += ipv6_optlen(exthdr); 427 *nexthdr = &exthdr->nexthdr; 428 exthdr = (struct ipv6_opt_hdr *)(nh + offset); 429 } 430 431 return offset; 432 } 433 434 static int mip6_rthdr_init_state(struct xfrm_state *x) 435 { 436 if (x->id.spi) { 437 printk(KERN_INFO "%s: spi is not 0: %u\n", __FUNCTION__, 438 x->id.spi); 439 return -EINVAL; 440 } 441 if (x->props.mode != XFRM_MODE_ROUTEOPTIMIZATION) { 442 printk(KERN_INFO "%s: state's mode is not %u: %u\n", 443 __FUNCTION__, XFRM_MODE_ROUTEOPTIMIZATION, x->props.mode); 444 return -EINVAL; 445 } 446 447 x->props.header_len = sizeof(struct rt2_hdr); 448 449 return 0; 450 } 451 452 /* 453 * Do nothing about destroying since it has no specific operation for routing 454 * header type 2 unlike IPsec protocols. 455 */ 456 static void mip6_rthdr_destroy(struct xfrm_state *x) 457 { 458 } 459 460 static struct xfrm_type mip6_rthdr_type = 461 { 462 .description = "MIP6RT", 463 .owner = THIS_MODULE, 464 .proto = IPPROTO_ROUTING, 465 .flags = XFRM_TYPE_NON_FRAGMENT, 466 .init_state = mip6_rthdr_init_state, 467 .destructor = mip6_rthdr_destroy, 468 .input = mip6_rthdr_input, 469 .output = mip6_rthdr_output, 470 .hdr_offset = mip6_rthdr_offset, 471 .remote_addr = mip6_xfrm_addr, 472 }; 473 474 int __init mip6_init(void) 475 { 476 printk(KERN_INFO "Mobile IPv6\n"); 477 478 if (xfrm_register_type(&mip6_destopt_type, AF_INET6) < 0) { 479 printk(KERN_INFO "%s: can't add xfrm type(destopt)\n", __FUNCTION__); 480 goto mip6_destopt_xfrm_fail; 481 } 482 if (xfrm_register_type(&mip6_rthdr_type, AF_INET6) < 0) { 483 printk(KERN_INFO "%s: can't add xfrm type(rthdr)\n", __FUNCTION__); 484 goto mip6_rthdr_xfrm_fail; 485 } 486 return 0; 487 488 mip6_rthdr_xfrm_fail: 489 xfrm_unregister_type(&mip6_destopt_type, AF_INET6); 490 mip6_destopt_xfrm_fail: 491 return -EAGAIN; 492 } 493 494 void __exit mip6_fini(void) 495 { 496 if (xfrm_unregister_type(&mip6_rthdr_type, AF_INET6) < 0) 497 printk(KERN_INFO "%s: can't remove xfrm type(rthdr)\n", __FUNCTION__); 498 if (xfrm_unregister_type(&mip6_destopt_type, AF_INET6) < 0) 499 printk(KERN_INFO "%s: can't remove xfrm type(destopt)\n", __FUNCTION__); 500 } 501