Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet6/in6_src.c
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1 /* $FreeBSD$ */ 2 /* $KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $ */ 3 4 /*- 5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the project nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 /*- 34 * Copyright (c) 1982, 1986, 1991, 1993 35 * The Regents of the University of California. All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 4. Neither the name of the University nor the names of its contributors 46 * may be used to endorse or promote products derived from this software 47 * without specific prior written permission. 48 * 49 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 50 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 51 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 52 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 53 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 54 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 55 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 56 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 57 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 58 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 59 * SUCH DAMAGE. 60 * 61 * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94 62 */ 63 64 #include "opt_inet.h" 65 #include "opt_inet6.h" 66 67 #include <sys/param.h> 68 #include <sys/systm.h> 69 #include <sys/lock.h> 70 #include <sys/malloc.h> 71 #include <sys/mbuf.h> 72 #include <sys/priv.h> 73 #include <sys/protosw.h> 74 #include <sys/socket.h> 75 #include <sys/socketvar.h> 76 #include <sys/sockio.h> 77 #include <sys/sysctl.h> 78 #include <sys/errno.h> 79 #include <sys/time.h> 80 #include <sys/kernel.h> 81 #include <sys/sx.h> 82 83 #include <net/if.h> 84 #include <net/route.h> 85 86 #include <netinet/in.h> 87 #include <netinet/in_var.h> 88 #include <netinet/in_systm.h> 89 #include <netinet/ip.h> 90 #include <netinet/in_pcb.h> 91 #include <netinet6/in6_var.h> 92 #include <netinet/ip6.h> 93 #include <netinet6/in6_pcb.h> 94 #include <netinet6/ip6_var.h> 95 #include <netinet6/scope6_var.h> 96 #include <netinet6/nd6.h> 97 98 static struct mtx addrsel_lock; 99 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF) 100 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock) 101 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock) 102 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED) 103 104 static struct sx addrsel_sxlock; 105 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock") 106 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock) 107 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock) 108 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock) 109 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock) 110 111 #define ADDR_LABEL_NOTAPP (-1) 112 struct in6_addrpolicy defaultaddrpolicy; 113 114 int ip6_prefer_tempaddr = 0; 115 116 static int selectroute __P((struct sockaddr_in6 *, struct ip6_pktopts *, 117 struct ip6_moptions *, struct route_in6 *, struct ifnet **, 118 struct rtentry **, int, int)); 119 static int in6_selectif __P((struct sockaddr_in6 *, struct ip6_pktopts *, 120 struct ip6_moptions *, struct route_in6 *ro, struct ifnet **)); 121 122 static struct in6_addrpolicy *lookup_addrsel_policy __P((struct sockaddr_in6 *)); 123 124 static void init_policy_queue __P((void)); 125 static int add_addrsel_policyent __P((struct in6_addrpolicy *)); 126 static int delete_addrsel_policyent __P((struct in6_addrpolicy *)); 127 static int walk_addrsel_policy __P((int (*)(struct in6_addrpolicy *, void *), 128 void *)); 129 static int dump_addrsel_policyent __P((struct in6_addrpolicy *, void *)); 130 static struct in6_addrpolicy *match_addrsel_policy __P((struct sockaddr_in6 *)); 131 132 /* 133 * Return an IPv6 address, which is the most appropriate for a given 134 * destination and user specified options. 135 * If necessary, this function lookups the routing table and returns 136 * an entry to the caller for later use. 137 */ 138 #define REPLACE(r) do {\ 139 if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \ 140 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ 141 ip6stat.ip6s_sources_rule[(r)]++; \ 142 /* printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \ 143 goto replace; \ 144 } while(0) 145 #define NEXT(r) do {\ 146 if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \ 147 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ 148 ip6stat.ip6s_sources_rule[(r)]++; \ 149 /* printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(&ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(&ia->ia_addr.sin6_addr), (r)); */ \ 150 goto next; /* XXX: we can't use 'continue' here */ \ 151 } while(0) 152 #define BREAK(r) do { \ 153 if ((r) < sizeof(ip6stat.ip6s_sources_rule) / \ 154 sizeof(ip6stat.ip6s_sources_rule[0])) /* check for safety */ \ 155 ip6stat.ip6s_sources_rule[(r)]++; \ 156 goto out; /* XXX: we can't use 'break' here */ \ 157 } while(0) 158 159 struct in6_addr * 160 in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 161 struct ip6_moptions *mopts, struct route_in6 *ro, 162 struct in6_addr *laddr, struct ifnet **ifpp, int *errorp) 163 { 164 struct in6_addr dst; 165 struct ifnet *ifp = NULL; 166 struct in6_ifaddr *ia = NULL, *ia_best = NULL; 167 struct in6_pktinfo *pi = NULL; 168 int dst_scope = -1, best_scope = -1, best_matchlen = -1; 169 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL; 170 u_int32_t odstzone; 171 int prefer_tempaddr; 172 173 dst = dstsock->sin6_addr; /* make a copy for local operation */ 174 *errorp = 0; 175 if (ifpp) 176 *ifpp = NULL; 177 178 /* 179 * If the source address is explicitly specified by the caller, 180 * check if the requested source address is indeed a unicast address 181 * assigned to the node, and can be used as the packet's source 182 * address. If everything is okay, use the address as source. 183 */ 184 if (opts && (pi = opts->ip6po_pktinfo) && 185 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 186 struct sockaddr_in6 srcsock; 187 struct in6_ifaddr *ia6; 188 189 /* get the outgoing interface */ 190 if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) 191 != 0) { 192 return (NULL); 193 } 194 195 /* 196 * determine the appropriate zone id of the source based on 197 * the zone of the destination and the outgoing interface. 198 * If the specified address is ambiguous wrt the scope zone, 199 * the interface must be specified; otherwise, ifa_ifwithaddr() 200 * will fail matching the address. 201 */ 202 bzero(&srcsock, sizeof(srcsock)); 203 srcsock.sin6_family = AF_INET6; 204 srcsock.sin6_len = sizeof(srcsock); 205 srcsock.sin6_addr = pi->ipi6_addr; 206 if (ifp) { 207 *errorp = in6_setscope(&srcsock.sin6_addr, ifp, NULL); 208 if (*errorp != 0) 209 return (NULL); 210 } 211 212 ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock)); 213 if (ia6 == NULL || 214 (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) { 215 *errorp = EADDRNOTAVAIL; 216 return (NULL); 217 } 218 pi->ipi6_addr = srcsock.sin6_addr; /* XXX: this overrides pi */ 219 if (ifpp) 220 *ifpp = ifp; 221 return (&ia6->ia_addr.sin6_addr); 222 } 223 224 /* 225 * Otherwise, if the socket has already bound the source, just use it. 226 */ 227 if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) 228 return (laddr); 229 230 /* 231 * If the address is not specified, choose the best one based on 232 * the outgoing interface and the destination address. 233 */ 234 /* get the outgoing interface */ 235 if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) != 0) 236 return (NULL); 237 238 #ifdef DIAGNOSTIC 239 if (ifp == NULL) /* this should not happen */ 240 panic("in6_selectsrc: NULL ifp"); 241 #endif 242 *errorp = in6_setscope(&dst, ifp, &odstzone); 243 if (*errorp != 0) 244 return (NULL); 245 246 for (ia = in6_ifaddr; ia; ia = ia->ia_next) { 247 int new_scope = -1, new_matchlen = -1; 248 struct in6_addrpolicy *new_policy = NULL; 249 u_int32_t srczone, osrczone, dstzone; 250 struct in6_addr src; 251 struct ifnet *ifp1 = ia->ia_ifp; 252 253 /* 254 * We'll never take an address that breaks the scope zone 255 * of the destination. We also skip an address if its zone 256 * does not contain the outgoing interface. 257 * XXX: we should probably use sin6_scope_id here. 258 */ 259 if (in6_setscope(&dst, ifp1, &dstzone) || 260 odstzone != dstzone) { 261 continue; 262 } 263 src = ia->ia_addr.sin6_addr; 264 if (in6_setscope(&src, ifp, &osrczone) || 265 in6_setscope(&src, ifp1, &srczone) || 266 osrczone != srczone) { 267 continue; 268 } 269 270 /* avoid unusable addresses */ 271 if ((ia->ia6_flags & 272 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { 273 continue; 274 } 275 if (!ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) 276 continue; 277 278 /* Rule 1: Prefer same address */ 279 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { 280 ia_best = ia; 281 BREAK(1); /* there should be no better candidate */ 282 } 283 284 if (ia_best == NULL) 285 REPLACE(0); 286 287 /* Rule 2: Prefer appropriate scope */ 288 if (dst_scope < 0) 289 dst_scope = in6_addrscope(&dst); 290 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); 291 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { 292 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) 293 REPLACE(2); 294 NEXT(2); 295 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { 296 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) 297 NEXT(2); 298 REPLACE(2); 299 } 300 301 /* 302 * Rule 3: Avoid deprecated addresses. Note that the case of 303 * !ip6_use_deprecated is already rejected above. 304 */ 305 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) 306 NEXT(3); 307 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) 308 REPLACE(3); 309 310 /* Rule 4: Prefer home addresses */ 311 /* 312 * XXX: This is a TODO. We should probably merge the MIP6 313 * case above. 314 */ 315 316 /* Rule 5: Prefer outgoing interface */ 317 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) 318 NEXT(5); 319 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) 320 REPLACE(5); 321 322 /* 323 * Rule 6: Prefer matching label 324 * Note that best_policy should be non-NULL here. 325 */ 326 if (dst_policy == NULL) 327 dst_policy = lookup_addrsel_policy(dstsock); 328 if (dst_policy->label != ADDR_LABEL_NOTAPP) { 329 new_policy = lookup_addrsel_policy(&ia->ia_addr); 330 if (dst_policy->label == best_policy->label && 331 dst_policy->label != new_policy->label) 332 NEXT(6); 333 if (dst_policy->label != best_policy->label && 334 dst_policy->label == new_policy->label) 335 REPLACE(6); 336 } 337 338 /* 339 * Rule 7: Prefer public addresses. 340 * We allow users to reverse the logic by configuring 341 * a sysctl variable, so that privacy conscious users can 342 * always prefer temporary addresses. 343 */ 344 if (opts == NULL || 345 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { 346 prefer_tempaddr = ip6_prefer_tempaddr; 347 } else if (opts->ip6po_prefer_tempaddr == 348 IP6PO_TEMPADDR_NOTPREFER) { 349 prefer_tempaddr = 0; 350 } else 351 prefer_tempaddr = 1; 352 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 353 (ia->ia6_flags & IN6_IFF_TEMPORARY)) { 354 if (prefer_tempaddr) 355 REPLACE(7); 356 else 357 NEXT(7); 358 } 359 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 360 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { 361 if (prefer_tempaddr) 362 NEXT(7); 363 else 364 REPLACE(7); 365 } 366 367 /* 368 * Rule 8: prefer addresses on alive interfaces. 369 * This is a KAME specific rule. 370 */ 371 if ((ia_best->ia_ifp->if_flags & IFF_UP) && 372 !(ia->ia_ifp->if_flags & IFF_UP)) 373 NEXT(8); 374 if (!(ia_best->ia_ifp->if_flags & IFF_UP) && 375 (ia->ia_ifp->if_flags & IFF_UP)) 376 REPLACE(8); 377 378 /* 379 * Rule 14: Use longest matching prefix. 380 * Note: in the address selection draft, this rule is 381 * documented as "Rule 8". However, since it is also 382 * documented that this rule can be overridden, we assign 383 * a large number so that it is easy to assign smaller numbers 384 * to more preferred rules. 385 */ 386 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); 387 if (best_matchlen < new_matchlen) 388 REPLACE(14); 389 if (new_matchlen < best_matchlen) 390 NEXT(14); 391 392 /* Rule 15 is reserved. */ 393 394 /* 395 * Last resort: just keep the current candidate. 396 * Or, do we need more rules? 397 */ 398 continue; 399 400 replace: 401 ia_best = ia; 402 best_scope = (new_scope >= 0 ? new_scope : 403 in6_addrscope(&ia_best->ia_addr.sin6_addr)); 404 best_policy = (new_policy ? new_policy : 405 lookup_addrsel_policy(&ia_best->ia_addr)); 406 best_matchlen = (new_matchlen >= 0 ? new_matchlen : 407 in6_matchlen(&ia_best->ia_addr.sin6_addr, 408 &dst)); 409 410 next: 411 continue; 412 413 out: 414 break; 415 } 416 417 if ((ia = ia_best) == NULL) { 418 *errorp = EADDRNOTAVAIL; 419 return (NULL); 420 } 421 422 if (ifpp) 423 *ifpp = ifp; 424 425 return (&ia->ia_addr.sin6_addr); 426 } 427 428 /* 429 * clone - meaningful only for bsdi and freebsd 430 */ 431 static int 432 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 433 struct ip6_moptions *mopts, struct route_in6 *ro, 434 struct ifnet **retifp, struct rtentry **retrt, int clone, 435 int norouteok) 436 { 437 int error = 0; 438 struct ifnet *ifp = NULL; 439 struct rtentry *rt = NULL; 440 struct sockaddr_in6 *sin6_next; 441 struct in6_pktinfo *pi = NULL; 442 struct in6_addr *dst = &dstsock->sin6_addr; 443 #if 0 444 char ip6buf[INET6_ADDRSTRLEN]; 445 446 if (dstsock->sin6_addr.s6_addr32[0] == 0 && 447 dstsock->sin6_addr.s6_addr32[1] == 0 && 448 !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) { 449 printf("in6_selectroute: strange destination %s\n", 450 ip6_sprintf(ip6buf, &dstsock->sin6_addr)); 451 } else { 452 printf("in6_selectroute: destination = %s%%%d\n", 453 ip6_sprintf(ip6buf, &dstsock->sin6_addr), 454 dstsock->sin6_scope_id); /* for debug */ 455 } 456 #endif 457 458 /* If the caller specify the outgoing interface explicitly, use it. */ 459 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 460 /* XXX boundary check is assumed to be already done. */ 461 ifp = ifnet_byindex(pi->ipi6_ifindex); 462 if (ifp != NULL && 463 (norouteok || retrt == NULL || 464 IN6_IS_ADDR_MULTICAST(dst))) { 465 /* 466 * we do not have to check or get the route for 467 * multicast. 468 */ 469 goto done; 470 } else 471 goto getroute; 472 } 473 474 /* 475 * If the destination address is a multicast address and the outgoing 476 * interface for the address is specified by the caller, use it. 477 */ 478 if (IN6_IS_ADDR_MULTICAST(dst) && 479 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 480 goto done; /* we do not need a route for multicast. */ 481 } 482 483 getroute: 484 /* 485 * If the next hop address for the packet is specified by the caller, 486 * use it as the gateway. 487 */ 488 if (opts && opts->ip6po_nexthop) { 489 struct route_in6 *ron; 490 491 sin6_next = satosin6(opts->ip6po_nexthop); 492 493 /* at this moment, we only support AF_INET6 next hops */ 494 if (sin6_next->sin6_family != AF_INET6) { 495 error = EAFNOSUPPORT; /* or should we proceed? */ 496 goto done; 497 } 498 499 /* 500 * If the next hop is an IPv6 address, then the node identified 501 * by that address must be a neighbor of the sending host. 502 */ 503 ron = &opts->ip6po_nextroute; 504 if ((ron->ro_rt && 505 (ron->ro_rt->rt_flags & (RTF_UP | RTF_LLINFO)) != 506 (RTF_UP | RTF_LLINFO)) || 507 !IN6_ARE_ADDR_EQUAL(&satosin6(&ron->ro_dst)->sin6_addr, 508 &sin6_next->sin6_addr)) { 509 if (ron->ro_rt) { 510 RTFREE(ron->ro_rt); 511 ron->ro_rt = NULL; 512 } 513 *satosin6(&ron->ro_dst) = *sin6_next; 514 } 515 if (ron->ro_rt == NULL) { 516 rtalloc((struct route *)ron); /* multi path case? */ 517 if (ron->ro_rt == NULL || 518 !(ron->ro_rt->rt_flags & RTF_LLINFO)) { 519 if (ron->ro_rt) { 520 RTFREE(ron->ro_rt); 521 ron->ro_rt = NULL; 522 } 523 error = EHOSTUNREACH; 524 goto done; 525 } 526 } 527 rt = ron->ro_rt; 528 ifp = rt->rt_ifp; 529 530 /* 531 * When cloning is required, try to allocate a route to the 532 * destination so that the caller can store path MTU 533 * information. 534 */ 535 if (!clone) 536 goto done; 537 } 538 539 /* 540 * Use a cached route if it exists and is valid, else try to allocate 541 * a new one. Note that we should check the address family of the 542 * cached destination, in case of sharing the cache with IPv4. 543 */ 544 if (ro) { 545 if (ro->ro_rt && 546 (!(ro->ro_rt->rt_flags & RTF_UP) || 547 ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 || 548 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, 549 dst))) { 550 RTFREE(ro->ro_rt); 551 ro->ro_rt = (struct rtentry *)NULL; 552 } 553 if (ro->ro_rt == (struct rtentry *)NULL) { 554 struct sockaddr_in6 *sa6; 555 556 /* No route yet, so try to acquire one */ 557 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 558 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 559 *sa6 = *dstsock; 560 sa6->sin6_scope_id = 0; 561 562 if (clone) { 563 rtalloc((struct route *)ro); 564 } else { 565 ro->ro_rt = rtalloc1(&((struct route *)ro) 566 ->ro_dst, 0, 0UL); 567 if (ro->ro_rt) 568 RT_UNLOCK(ro->ro_rt); 569 } 570 } 571 572 /* 573 * do not care about the result if we have the nexthop 574 * explicitly specified. 575 */ 576 if (opts && opts->ip6po_nexthop) 577 goto done; 578 579 if (ro->ro_rt) { 580 ifp = ro->ro_rt->rt_ifp; 581 582 if (ifp == NULL) { /* can this really happen? */ 583 RTFREE(ro->ro_rt); 584 ro->ro_rt = NULL; 585 } 586 } 587 if (ro->ro_rt == NULL) 588 error = EHOSTUNREACH; 589 rt = ro->ro_rt; 590 591 /* 592 * Check if the outgoing interface conflicts with 593 * the interface specified by ipi6_ifindex (if specified). 594 * Note that loopback interface is always okay. 595 * (this may happen when we are sending a packet to one of 596 * our own addresses.) 597 */ 598 if (ifp && opts && opts->ip6po_pktinfo && 599 opts->ip6po_pktinfo->ipi6_ifindex) { 600 if (!(ifp->if_flags & IFF_LOOPBACK) && 601 ifp->if_index != 602 opts->ip6po_pktinfo->ipi6_ifindex) { 603 error = EHOSTUNREACH; 604 goto done; 605 } 606 } 607 } 608 609 done: 610 if (ifp == NULL && rt == NULL) { 611 /* 612 * This can happen if the caller did not pass a cached route 613 * nor any other hints. We treat this case an error. 614 */ 615 error = EHOSTUNREACH; 616 } 617 if (error == EHOSTUNREACH) 618 ip6stat.ip6s_noroute++; 619 620 if (retifp != NULL) 621 *retifp = ifp; 622 if (retrt != NULL) 623 *retrt = rt; /* rt may be NULL */ 624 625 return (error); 626 } 627 628 static int 629 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 630 struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp) 631 { 632 int error; 633 struct route_in6 sro; 634 struct rtentry *rt = NULL; 635 636 if (ro == NULL) { 637 bzero(&sro, sizeof(sro)); 638 ro = &sro; 639 } 640 641 if ((error = selectroute(dstsock, opts, mopts, ro, retifp, 642 &rt, 0, 1)) != 0) { 643 if (ro == &sro && rt && rt == sro.ro_rt) 644 RTFREE(rt); 645 return (error); 646 } 647 648 /* 649 * do not use a rejected or black hole route. 650 * XXX: this check should be done in the L2 output routine. 651 * However, if we skipped this check here, we'd see the following 652 * scenario: 653 * - install a rejected route for a scoped address prefix 654 * (like fe80::/10) 655 * - send a packet to a destination that matches the scoped prefix, 656 * with ambiguity about the scope zone. 657 * - pick the outgoing interface from the route, and disambiguate the 658 * scope zone with the interface. 659 * - ip6_output() would try to get another route with the "new" 660 * destination, which may be valid. 661 * - we'd see no error on output. 662 * Although this may not be very harmful, it should still be confusing. 663 * We thus reject the case here. 664 */ 665 if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) { 666 int flags = (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 667 668 if (ro == &sro && rt && rt == sro.ro_rt) 669 RTFREE(rt); 670 return (flags); 671 } 672 673 /* 674 * Adjust the "outgoing" interface. If we're going to loop the packet 675 * back to ourselves, the ifp would be the loopback interface. 676 * However, we'd rather know the interface associated to the 677 * destination address (which should probably be one of our own 678 * addresses.) 679 */ 680 if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp) 681 *retifp = rt->rt_ifa->ifa_ifp; 682 683 if (ro == &sro && rt && rt == sro.ro_rt) 684 RTFREE(rt); 685 return (0); 686 } 687 688 /* 689 * clone - meaningful only for bsdi and freebsd 690 */ 691 int 692 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 693 struct ip6_moptions *mopts, struct route_in6 *ro, 694 struct ifnet **retifp, struct rtentry **retrt, int clone) 695 { 696 697 return (selectroute(dstsock, opts, mopts, ro, retifp, 698 retrt, clone, 0)); 699 } 700 701 /* 702 * Default hop limit selection. The precedence is as follows: 703 * 1. Hoplimit value specified via ioctl. 704 * 2. (If the outgoing interface is detected) the current 705 * hop limit of the interface specified by router advertisement. 706 * 3. The system default hoplimit. 707 */ 708 int 709 in6_selecthlim(struct in6pcb *in6p, struct ifnet *ifp) 710 { 711 712 if (in6p && in6p->in6p_hops >= 0) 713 return (in6p->in6p_hops); 714 else if (ifp) 715 return (ND_IFINFO(ifp)->chlim); 716 else if (in6p && !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) { 717 struct route_in6 ro6; 718 struct ifnet *lifp; 719 720 bzero(&ro6, sizeof(ro6)); 721 ro6.ro_dst.sin6_family = AF_INET6; 722 ro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6); 723 ro6.ro_dst.sin6_addr = in6p->in6p_faddr; 724 rtalloc((struct route *)&ro6); 725 if (ro6.ro_rt) { 726 lifp = ro6.ro_rt->rt_ifp; 727 RTFREE(ro6.ro_rt); 728 if (lifp) 729 return (ND_IFINFO(lifp)->chlim); 730 } else 731 return (ip6_defhlim); 732 } 733 return (ip6_defhlim); 734 } 735 736 /* 737 * XXX: this is borrowed from in6_pcbbind(). If possible, we should 738 * share this function by all *bsd*... 739 */ 740 int 741 in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct ucred *cred) 742 { 743 struct socket *so = inp->inp_socket; 744 u_int16_t lport = 0, first, last, *lastport; 745 int count, error = 0, wild = 0; 746 struct inpcbinfo *pcbinfo = inp->inp_pcbinfo; 747 748 INP_INFO_WLOCK_ASSERT(pcbinfo); 749 INP_LOCK_ASSERT(inp); 750 751 /* XXX: this is redundant when called from in6_pcbbind */ 752 if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0) 753 wild = INPLOOKUP_WILDCARD; 754 755 inp->inp_flags |= INP_ANONPORT; 756 757 if (inp->inp_flags & INP_HIGHPORT) { 758 first = ipport_hifirstauto; /* sysctl */ 759 last = ipport_hilastauto; 760 lastport = &pcbinfo->ipi_lasthi; 761 } else if (inp->inp_flags & INP_LOWPORT) { 762 error = priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT, 0); 763 if (error) 764 return error; 765 first = ipport_lowfirstauto; /* 1023 */ 766 last = ipport_lowlastauto; /* 600 */ 767 lastport = &pcbinfo->ipi_lastlow; 768 } else { 769 first = ipport_firstauto; /* sysctl */ 770 last = ipport_lastauto; 771 lastport = &pcbinfo->ipi_lastport; 772 } 773 /* 774 * Simple check to ensure all ports are not used up causing 775 * a deadlock here. 776 * 777 * We split the two cases (up and down) so that the direction 778 * is not being tested on each round of the loop. 779 */ 780 if (first > last) { 781 /* 782 * counting down 783 */ 784 count = first - last; 785 786 do { 787 if (count-- < 0) { /* completely used? */ 788 /* 789 * Undo any address bind that may have 790 * occurred above. 791 */ 792 inp->in6p_laddr = in6addr_any; 793 return (EAGAIN); 794 } 795 --*lastport; 796 if (*lastport > first || *lastport < last) 797 *lastport = first; 798 lport = htons(*lastport); 799 } while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr, 800 lport, wild)); 801 } else { 802 /* 803 * counting up 804 */ 805 count = last - first; 806 807 do { 808 if (count-- < 0) { /* completely used? */ 809 /* 810 * Undo any address bind that may have 811 * occurred above. 812 */ 813 inp->in6p_laddr = in6addr_any; 814 return (EAGAIN); 815 } 816 ++*lastport; 817 if (*lastport < first || *lastport > last) 818 *lastport = first; 819 lport = htons(*lastport); 820 } while (in6_pcblookup_local(pcbinfo, 821 &inp->in6p_laddr, lport, wild)); 822 } 823 824 inp->inp_lport = lport; 825 if (in_pcbinshash(inp) != 0) { 826 inp->in6p_laddr = in6addr_any; 827 inp->inp_lport = 0; 828 return (EAGAIN); 829 } 830 831 return (0); 832 } 833 834 void 835 addrsel_policy_init(void) 836 { 837 ADDRSEL_LOCK_INIT(); 838 ADDRSEL_SXLOCK_INIT(); 839 840 init_policy_queue(); 841 842 /* initialize the "last resort" policy */ 843 bzero(&defaultaddrpolicy, sizeof(defaultaddrpolicy)); 844 defaultaddrpolicy.label = ADDR_LABEL_NOTAPP; 845 } 846 847 static struct in6_addrpolicy * 848 lookup_addrsel_policy(struct sockaddr_in6 *key) 849 { 850 struct in6_addrpolicy *match = NULL; 851 852 ADDRSEL_LOCK(); 853 match = match_addrsel_policy(key); 854 855 if (match == NULL) 856 match = &defaultaddrpolicy; 857 else 858 match->use++; 859 ADDRSEL_UNLOCK(); 860 861 return (match); 862 } 863 864 /* 865 * Subroutines to manage the address selection policy table via sysctl. 866 */ 867 struct walkarg { 868 struct sysctl_req *w_req; 869 }; 870 871 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS); 872 SYSCTL_DECL(_net_inet6_ip6); 873 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy, 874 CTLFLAG_RD, in6_src_sysctl, ""); 875 876 static int 877 in6_src_sysctl(SYSCTL_HANDLER_ARGS) 878 { 879 struct walkarg w; 880 881 if (req->newptr) 882 return EPERM; 883 884 bzero(&w, sizeof(w)); 885 w.w_req = req; 886 887 return (walk_addrsel_policy(dump_addrsel_policyent, &w)); 888 } 889 890 int 891 in6_src_ioctl(u_long cmd, caddr_t data) 892 { 893 int i; 894 struct in6_addrpolicy ent0; 895 896 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY) 897 return (EOPNOTSUPP); /* check for safety */ 898 899 ent0 = *(struct in6_addrpolicy *)data; 900 901 if (ent0.label == ADDR_LABEL_NOTAPP) 902 return (EINVAL); 903 /* check if the prefix mask is consecutive. */ 904 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0) 905 return (EINVAL); 906 /* clear trailing garbages (if any) of the prefix address. */ 907 for (i = 0; i < 4; i++) { 908 ent0.addr.sin6_addr.s6_addr32[i] &= 909 ent0.addrmask.sin6_addr.s6_addr32[i]; 910 } 911 ent0.use = 0; 912 913 switch (cmd) { 914 case SIOCAADDRCTL_POLICY: 915 return (add_addrsel_policyent(&ent0)); 916 case SIOCDADDRCTL_POLICY: 917 return (delete_addrsel_policyent(&ent0)); 918 } 919 920 return (0); /* XXX: compromise compilers */ 921 } 922 923 /* 924 * The followings are implementation of the policy table using a 925 * simple tail queue. 926 * XXX such details should be hidden. 927 * XXX implementation using binary tree should be more efficient. 928 */ 929 struct addrsel_policyent { 930 TAILQ_ENTRY(addrsel_policyent) ape_entry; 931 struct in6_addrpolicy ape_policy; 932 }; 933 934 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent); 935 936 struct addrsel_policyhead addrsel_policytab; 937 938 static void 939 init_policy_queue(void) 940 { 941 942 TAILQ_INIT(&addrsel_policytab); 943 } 944 945 static int 946 add_addrsel_policyent(struct in6_addrpolicy *newpolicy) 947 { 948 struct addrsel_policyent *new, *pol; 949 950 MALLOC(new, struct addrsel_policyent *, sizeof(*new), M_IFADDR, 951 M_WAITOK); 952 ADDRSEL_XLOCK(); 953 ADDRSEL_LOCK(); 954 955 /* duplication check */ 956 TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) { 957 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr, 958 &pol->ape_policy.addr.sin6_addr) && 959 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr, 960 &pol->ape_policy.addrmask.sin6_addr)) { 961 ADDRSEL_UNLOCK(); 962 ADDRSEL_XUNLOCK(); 963 FREE(new, M_IFADDR); 964 return (EEXIST); /* or override it? */ 965 } 966 } 967 968 bzero(new, sizeof(*new)); 969 970 /* XXX: should validate entry */ 971 new->ape_policy = *newpolicy; 972 973 TAILQ_INSERT_TAIL(&addrsel_policytab, new, ape_entry); 974 ADDRSEL_UNLOCK(); 975 ADDRSEL_XUNLOCK(); 976 977 return (0); 978 } 979 980 static int 981 delete_addrsel_policyent(struct in6_addrpolicy *key) 982 { 983 struct addrsel_policyent *pol; 984 985 ADDRSEL_XLOCK(); 986 ADDRSEL_LOCK(); 987 988 /* search for the entry in the table */ 989 TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) { 990 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr, 991 &pol->ape_policy.addr.sin6_addr) && 992 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr, 993 &pol->ape_policy.addrmask.sin6_addr)) { 994 break; 995 } 996 } 997 if (pol == NULL) { 998 ADDRSEL_UNLOCK(); 999 ADDRSEL_XUNLOCK(); 1000 return (ESRCH); 1001 } 1002 1003 TAILQ_REMOVE(&addrsel_policytab, pol, ape_entry); 1004 ADDRSEL_UNLOCK(); 1005 ADDRSEL_XUNLOCK(); 1006 1007 return (0); 1008 } 1009 1010 static int 1011 walk_addrsel_policy(int (*callback) __P((struct in6_addrpolicy *, void *)), 1012 void *w) 1013 { 1014 struct addrsel_policyent *pol; 1015 int error = 0; 1016 1017 ADDRSEL_SLOCK(); 1018 TAILQ_FOREACH(pol, &addrsel_policytab, ape_entry) { 1019 if ((error = (*callback)(&pol->ape_policy, w)) != 0) { 1020 ADDRSEL_SUNLOCK(); 1021 return (error); 1022 } 1023 } 1024 ADDRSEL_SUNLOCK(); 1025 return (error); 1026 } 1027 1028 static int 1029 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg) 1030 { 1031 int error = 0; 1032 struct walkarg *w = arg; 1033 1034 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol)); 1035 1036 return (error); 1037 } 1038 1039 static struct in6_addrpolicy * 1040 match_addrsel_policy(struct sockaddr_in6 *key) 1041 { 1042 struct addrsel_policyent *pent; 1043 struct in6_addrpolicy *bestpol = NULL, *pol; 1044 int matchlen, bestmatchlen = -1; 1045 u_char *mp, *ep, *k, *p, m; 1046 1047 TAILQ_FOREACH(pent, &addrsel_policytab, ape_entry) { 1048 matchlen = 0; 1049 1050 pol = &pent->ape_policy; 1051 mp = (u_char *)&pol->addrmask.sin6_addr; 1052 ep = mp + 16; /* XXX: scope field? */ 1053 k = (u_char *)&key->sin6_addr; 1054 p = (u_char *)&pol->addr.sin6_addr; 1055 for (; mp < ep && *mp; mp++, k++, p++) { 1056 m = *mp; 1057 if ((*k & m) != *p) 1058 goto next; /* not match */ 1059 if (m == 0xff) /* short cut for a typical case */ 1060 matchlen += 8; 1061 else { 1062 while (m >= 0x80) { 1063 matchlen++; 1064 m <<= 1; 1065 } 1066 } 1067 } 1068 1069 /* matched. check if this is better than the current best. */ 1070 if (bestpol == NULL || 1071 matchlen > bestmatchlen) { 1072 bestpol = pol; 1073 bestmatchlen = matchlen; 1074 } 1075 1076 next: 1077 continue; 1078 } 1079 1080 return (bestpol); 1081 }
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