1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the project nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * $KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $ 32 */ 33 34 /*- 35 * Copyright (c) 1982, 1986, 1991, 1993 36 * The Regents of the University of California. All rights reserved. 37 * 38 * Redistribution and use in source and binary forms, with or without 39 * modification, are permitted provided that the following conditions 40 * are met: 41 * 1. Redistributions of source code must retain the above copyright 42 * notice, this list of conditions and the following disclaimer. 43 * 2. Redistributions in binary form must reproduce the above copyright 44 * notice, this list of conditions and the following disclaimer in the 45 * documentation and/or other materials provided with the distribution. 46 * 3. Neither the name of the University nor the names of its contributors 47 * may be used to endorse or promote products derived from this software 48 * without specific prior written permission. 49 * 50 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 51 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 52 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 53 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 54 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 56 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 57 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 58 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 59 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 60 * SUCH DAMAGE. 61 * 62 * @(#)in_pcb.c 8.2 (Berkeley) 1/4/94 63 */ 64 65 #include <sys/cdefs.h> 66 __FBSDID("$FreeBSD$"); 67 68 #include "opt_inet.h" 69 #include "opt_inet6.h" 70 #include <sys/param.h> 71 #include <sys/systm.h> 72 #include <sys/lock.h> 73 #include <sys/malloc.h> 74 #include <sys/mbuf.h> 75 #include <sys/priv.h> 76 #include <sys/protosw.h> 77 #include <sys/socket.h> 78 #include <sys/socketvar.h> 79 #include <sys/sockio.h> 80 #include <sys/sysctl.h> 81 #include <sys/errno.h> 82 #include <sys/time.h> 83 #include <sys/jail.h> 84 #include <sys/kernel.h> 85 #include <sys/rmlock.h> 86 #include <sys/sx.h> 87 88 #include <net/if.h> 89 #include <net/if_var.h> 90 #include <net/if_dl.h> 91 #include <net/route.h> 92 #include <net/route/nhop.h> 93 #include <net/if_llatbl.h> 94 95 #include <netinet/in.h> 96 #include <netinet/in_var.h> 97 #include <netinet/in_systm.h> 98 #include <netinet/ip.h> 99 #include <netinet/in_pcb.h> 100 #include <netinet/ip_var.h> 101 #include <netinet/udp.h> 102 #include <netinet/udp_var.h> 103 104 #include <netinet6/in6_var.h> 105 #include <netinet/ip6.h> 106 #include <netinet6/in6_fib.h> 107 #include <netinet6/in6_pcb.h> 108 #include <netinet6/ip6_var.h> 109 #include <netinet6/scope6_var.h> 110 #include <netinet6/nd6.h> 111 112 static struct mtx addrsel_lock; 113 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF) 114 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock) 115 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock) 116 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED) 117 118 static struct sx addrsel_sxlock; 119 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock") 120 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock) 121 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock) 122 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock) 123 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock) 124 125 #define ADDR_LABEL_NOTAPP (-1) 126 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy); 127 #define V_defaultaddrpolicy VNET(defaultaddrpolicy) 128 129 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0; 130 131 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *, 132 struct ip6_moptions *, struct route_in6 *, struct ifnet **, 133 struct nhop_object **, int, u_int, uint32_t); 134 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *, 135 struct ip6_moptions *, struct ifnet **, 136 struct ifnet *, u_int); 137 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *, 138 struct ip6_pktopts *, struct inpcb *, struct ucred *, 139 struct ifnet **, struct in6_addr *); 140 141 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *); 142 143 static void init_policy_queue(void); 144 static int add_addrsel_policyent(struct in6_addrpolicy *); 145 static int delete_addrsel_policyent(struct in6_addrpolicy *); 146 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *), 147 void *); 148 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *); 149 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *); 150 151 /* 152 * Return an IPv6 address, which is the most appropriate for a given 153 * destination and user specified options. 154 * If necessary, this function lookups the routing table and returns 155 * an entry to the caller for later use. 156 */ 157 #define REPLACE(r) do {\ 158 IP6STAT_INC(ip6s_sources_rule[(r)]); \ 159 /* { \ 160 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 161 printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \ 162 } */ \ 163 goto replace; \ 164 } while(0) 165 #define NEXT(r) do {\ 166 /* { \ 167 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 168 printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \ 169 } */ \ 170 goto next; /* XXX: we can't use 'continue' here */ \ 171 } while(0) 172 #define BREAK(r) do { \ 173 IP6STAT_INC(ip6s_sources_rule[(r)]); \ 174 goto out; /* XXX: we can't use 'break' here */ \ 175 } while(0) 176 177 static int 178 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock, 179 struct ip6_pktopts *opts, struct inpcb *inp, struct ucred *cred, 180 struct ifnet **ifpp, struct in6_addr *srcp) 181 { 182 struct rm_priotracker in6_ifa_tracker; 183 struct in6_addr dst, tmp; 184 struct ifnet *ifp = NULL, *oifp = NULL; 185 struct in6_ifaddr *ia = NULL, *ia_best = NULL; 186 struct in6_pktinfo *pi = NULL; 187 int dst_scope = -1, best_scope = -1, best_matchlen = -1; 188 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL; 189 u_int32_t odstzone; 190 int prefer_tempaddr; 191 int error; 192 struct ip6_moptions *mopts; 193 194 NET_EPOCH_ASSERT(); 195 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__)); 196 197 dst = dstsock->sin6_addr; /* make a copy for local operation */ 198 if (ifpp) { 199 /* 200 * Save a possibly passed in ifp for in6_selectsrc. Only 201 * neighbor discovery code should use this feature, where 202 * we may know the interface but not the FIB number holding 203 * the connected subnet in case someone deleted it from the 204 * default FIB and we need to check the interface. 205 */ 206 if (*ifpp != NULL) 207 oifp = *ifpp; 208 *ifpp = NULL; 209 } 210 211 if (inp != NULL) { 212 INP_LOCK_ASSERT(inp); 213 mopts = inp->in6p_moptions; 214 } else { 215 mopts = NULL; 216 } 217 218 /* 219 * If the source address is explicitly specified by the caller, 220 * check if the requested source address is indeed a unicast address 221 * assigned to the node, and can be used as the packet's source 222 * address. If everything is okay, use the address as source. 223 */ 224 if (opts && (pi = opts->ip6po_pktinfo) && 225 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 226 /* get the outgoing interface */ 227 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 228 fibnum)) 229 != 0) 230 return (error); 231 232 /* 233 * determine the appropriate zone id of the source based on 234 * the zone of the destination and the outgoing interface. 235 * If the specified address is ambiguous wrt the scope zone, 236 * the interface must be specified; otherwise, ifa_ifwithaddr() 237 * will fail matching the address. 238 */ 239 tmp = pi->ipi6_addr; 240 if (ifp) { 241 error = in6_setscope(&tmp, ifp, &odstzone); 242 if (error) 243 return (error); 244 } 245 if (cred != NULL && (error = prison_local_ip6(cred, 246 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) 247 return (error); 248 249 /* 250 * If IPV6_BINDANY socket option is set, we allow to specify 251 * non local addresses as source address in IPV6_PKTINFO 252 * ancillary data. 253 */ 254 if ((inp->inp_flags & INP_BINDANY) == 0) { 255 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */, false); 256 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST | 257 IN6_IFF_NOTREADY))) 258 return (EADDRNOTAVAIL); 259 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp)); 260 } else 261 bcopy(&tmp, srcp, sizeof(*srcp)); 262 pi->ipi6_addr = tmp; /* XXX: this overrides pi */ 263 if (ifpp) 264 *ifpp = ifp; 265 return (0); 266 } 267 268 /* 269 * Otherwise, if the socket has already bound the source, just use it. 270 */ 271 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) { 272 if (cred != NULL && 273 (error = prison_local_ip6(cred, &inp->in6p_laddr, 274 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0) 275 return (error); 276 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp)); 277 return (0); 278 } 279 280 /* 281 * Bypass source address selection and use the primary jail IP 282 * if requested. 283 */ 284 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp)) 285 return (0); 286 287 /* 288 * If the address is not specified, choose the best one based on 289 * the outgoing interface and the destination address. 290 */ 291 /* get the outgoing interface */ 292 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 293 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0) 294 return (error); 295 296 #ifdef DIAGNOSTIC 297 if (ifp == NULL) /* this should not happen */ 298 panic("in6_selectsrc: NULL ifp"); 299 #endif 300 error = in6_setscope(&dst, ifp, &odstzone); 301 if (error) 302 return (error); 303 304 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 305 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 306 int new_scope = -1, new_matchlen = -1; 307 struct in6_addrpolicy *new_policy = NULL; 308 u_int32_t srczone, osrczone, dstzone; 309 struct in6_addr src; 310 struct ifnet *ifp1 = ia->ia_ifp; 311 312 /* 313 * We'll never take an address that breaks the scope zone 314 * of the destination. We also skip an address if its zone 315 * does not contain the outgoing interface. 316 * XXX: we should probably use sin6_scope_id here. 317 */ 318 if (in6_setscope(&dst, ifp1, &dstzone) || 319 odstzone != dstzone) { 320 continue; 321 } 322 src = ia->ia_addr.sin6_addr; 323 if (in6_setscope(&src, ifp, &osrczone) || 324 in6_setscope(&src, ifp1, &srczone) || 325 osrczone != srczone) { 326 continue; 327 } 328 329 /* avoid unusable addresses */ 330 if ((ia->ia6_flags & 331 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { 332 continue; 333 } 334 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) 335 continue; 336 337 /* If jailed only take addresses of the jail into account. */ 338 if (cred != NULL && 339 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0) 340 continue; 341 342 /* Rule 1: Prefer same address */ 343 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { 344 ia_best = ia; 345 BREAK(1); /* there should be no better candidate */ 346 } 347 348 if (ia_best == NULL) 349 REPLACE(0); 350 351 /* Rule 2: Prefer appropriate scope */ 352 if (dst_scope < 0) 353 dst_scope = in6_addrscope(&dst); 354 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); 355 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { 356 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) 357 REPLACE(2); 358 NEXT(2); 359 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { 360 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) 361 NEXT(2); 362 REPLACE(2); 363 } 364 365 /* 366 * Rule 3: Avoid deprecated addresses. Note that the case of 367 * !ip6_use_deprecated is already rejected above. 368 */ 369 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) 370 NEXT(3); 371 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) 372 REPLACE(3); 373 374 /* Rule 4: Prefer home addresses */ 375 /* 376 * XXX: This is a TODO. We should probably merge the MIP6 377 * case above. 378 */ 379 380 /* Rule 5: Prefer outgoing interface */ 381 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) { 382 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) 383 NEXT(5); 384 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) 385 REPLACE(5); 386 } 387 388 /* 389 * Rule 6: Prefer matching label 390 * Note that best_policy should be non-NULL here. 391 */ 392 if (dst_policy == NULL) 393 dst_policy = lookup_addrsel_policy(dstsock); 394 if (dst_policy->label != ADDR_LABEL_NOTAPP) { 395 new_policy = lookup_addrsel_policy(&ia->ia_addr); 396 if (dst_policy->label == best_policy->label && 397 dst_policy->label != new_policy->label) 398 NEXT(6); 399 if (dst_policy->label != best_policy->label && 400 dst_policy->label == new_policy->label) 401 REPLACE(6); 402 } 403 404 /* 405 * Rule 7: Prefer public addresses. 406 * We allow users to reverse the logic by configuring 407 * a sysctl variable, so that privacy conscious users can 408 * always prefer temporary addresses. 409 */ 410 if (opts == NULL || 411 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { 412 prefer_tempaddr = V_ip6_prefer_tempaddr; 413 } else if (opts->ip6po_prefer_tempaddr == 414 IP6PO_TEMPADDR_NOTPREFER) { 415 prefer_tempaddr = 0; 416 } else 417 prefer_tempaddr = 1; 418 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 419 (ia->ia6_flags & IN6_IFF_TEMPORARY)) { 420 if (prefer_tempaddr) 421 REPLACE(7); 422 else 423 NEXT(7); 424 } 425 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 426 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { 427 if (prefer_tempaddr) 428 NEXT(7); 429 else 430 REPLACE(7); 431 } 432 433 /* 434 * Rule 8: prefer addresses on alive interfaces. 435 * This is a KAME specific rule. 436 */ 437 if ((ia_best->ia_ifp->if_flags & IFF_UP) && 438 !(ia->ia_ifp->if_flags & IFF_UP)) 439 NEXT(8); 440 if (!(ia_best->ia_ifp->if_flags & IFF_UP) && 441 (ia->ia_ifp->if_flags & IFF_UP)) 442 REPLACE(8); 443 444 /* 445 * Rule 9: prefer address with better virtual status. 446 */ 447 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa)) 448 REPLACE(9); 449 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa)) 450 NEXT(9); 451 452 /* 453 * Rule 10: prefer address with `prefer_source' flag. 454 */ 455 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 && 456 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0) 457 REPLACE(10); 458 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 && 459 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0) 460 NEXT(10); 461 462 /* 463 * Rule 14: Use longest matching prefix. 464 * Note: in the address selection draft, this rule is 465 * documented as "Rule 8". However, since it is also 466 * documented that this rule can be overridden, we assign 467 * a large number so that it is easy to assign smaller numbers 468 * to more preferred rules. 469 */ 470 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); 471 if (best_matchlen < new_matchlen) 472 REPLACE(14); 473 if (new_matchlen < best_matchlen) 474 NEXT(14); 475 476 /* Rule 15 is reserved. */ 477 478 /* 479 * Last resort: just keep the current candidate. 480 * Or, do we need more rules? 481 */ 482 continue; 483 484 replace: 485 ia_best = ia; 486 best_scope = (new_scope >= 0 ? new_scope : 487 in6_addrscope(&ia_best->ia_addr.sin6_addr)); 488 best_policy = (new_policy ? new_policy : 489 lookup_addrsel_policy(&ia_best->ia_addr)); 490 best_matchlen = (new_matchlen >= 0 ? new_matchlen : 491 in6_matchlen(&ia_best->ia_addr.sin6_addr, 492 &dst)); 493 494 next: 495 continue; 496 497 out: 498 break; 499 } 500 501 if ((ia = ia_best) == NULL) { 502 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 503 IP6STAT_INC(ip6s_sources_none); 504 return (EADDRNOTAVAIL); 505 } 506 507 /* 508 * At this point at least one of the addresses belonged to the jail 509 * but it could still be, that we want to further restrict it, e.g. 510 * theoratically IN6_IS_ADDR_LOOPBACK. 511 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore. 512 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should 513 * let all others previously selected pass. 514 * Use tmp to not change ::1 on lo0 to the primary jail address. 515 */ 516 tmp = ia->ia_addr.sin6_addr; 517 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL && 518 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) { 519 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 520 IP6STAT_INC(ip6s_sources_none); 521 return (EADDRNOTAVAIL); 522 } 523 524 if (ifpp) 525 *ifpp = ifp; 526 527 bcopy(&tmp, srcp, sizeof(*srcp)); 528 if (ia->ia_ifp == ifp) 529 IP6STAT_INC(ip6s_sources_sameif[best_scope]); 530 else 531 IP6STAT_INC(ip6s_sources_otherif[best_scope]); 532 if (dst_scope == best_scope) 533 IP6STAT_INC(ip6s_sources_samescope[best_scope]); 534 else 535 IP6STAT_INC(ip6s_sources_otherscope[best_scope]); 536 if (IFA6_IS_DEPRECATED(ia)) 537 IP6STAT_INC(ip6s_sources_deprecated[best_scope]); 538 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 539 return (0); 540 } 541 542 /* 543 * Select source address based on @inp, @dstsock and @opts. 544 * Stores selected address to @srcp. If @scope_ambiguous is set, 545 * embed scope from selected outgoing interface. If @hlim pointer 546 * is provided, stores calculated hop limit there. 547 * Returns 0 on success. 548 */ 549 int 550 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 551 struct inpcb *inp, struct ucred *cred, int scope_ambiguous, 552 struct in6_addr *srcp, int *hlim) 553 { 554 struct ifnet *retifp; 555 uint32_t fibnum; 556 int error; 557 558 fibnum = inp->inp_inc.inc_fibnum; 559 retifp = NULL; 560 561 error = in6_selectsrc(fibnum, dstsock, opts, inp, cred, &retifp, srcp); 562 if (error != 0) 563 return (error); 564 565 if (hlim != NULL) 566 *hlim = in6_selecthlim(inp, retifp); 567 568 if (retifp == NULL || scope_ambiguous == 0) 569 return (0); 570 571 /* 572 * Application should provide a proper zone ID or the use of 573 * default zone IDs should be enabled. Unfortunately, some 574 * applications do not behave as it should, so we need a 575 * workaround. Even if an appropriate ID is not determined 576 * (when it's required), if we can determine the outgoing 577 * interface. determine the zone ID based on the interface. 578 */ 579 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL); 580 581 return (error); 582 } 583 584 /* 585 * Select source address based on @fibnum, @dst and @scopeid. 586 * Stores selected address to @srcp. 587 * Returns 0 on success. 588 * 589 * Used by non-socket based consumers (ND code mostly) 590 */ 591 int 592 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst, 593 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp, 594 int *hlim) 595 { 596 struct ifnet *retifp; 597 struct sockaddr_in6 dst_sa; 598 int error; 599 600 retifp = ifp; 601 bzero(&dst_sa, sizeof(dst_sa)); 602 dst_sa.sin6_family = AF_INET6; 603 dst_sa.sin6_len = sizeof(dst_sa); 604 dst_sa.sin6_addr = *dst; 605 dst_sa.sin6_scope_id = scopeid; 606 sa6_embedscope(&dst_sa, 0); 607 608 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL, NULL, &retifp, srcp); 609 if (hlim != NULL) 610 *hlim = in6_selecthlim(NULL, retifp); 611 612 return (error); 613 } 614 615 static struct nhop_object * 616 cache_route(uint32_t fibnum, const struct sockaddr_in6 *dst, struct route_in6 *ro, 617 uint32_t flowid) 618 { 619 /* 620 * Use a cached route if it exists and is valid, else try to allocate 621 * a new one. Note that we should check the address family of the 622 * cached destination, in case of sharing the cache with IPv4. 623 * Assumes that 'struct route_in6' is exclusively locked. 624 */ 625 if (ro->ro_nh != NULL && ( 626 !NH_IS_VALID(ro->ro_nh) || ro->ro_dst.sin6_family != AF_INET6 || 627 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &dst->sin6_addr))) 628 RO_NHFREE(ro); 629 630 if (ro->ro_nh == NULL) { 631 ro->ro_dst = *dst; 632 633 const struct in6_addr *paddr; 634 struct in6_addr unscoped_addr; 635 uint32_t scopeid = 0; 636 if (IN6_IS_SCOPE_LINKLOCAL(&dst->sin6_addr)) { 637 in6_splitscope(&dst->sin6_addr, &unscoped_addr, &scopeid); 638 paddr = &unscoped_addr; 639 } else 640 paddr = &dst->sin6_addr; 641 ro->ro_nh = fib6_lookup(fibnum, paddr, scopeid, NHR_REF, flowid); 642 } 643 return (ro->ro_nh); 644 } 645 646 static struct nhop_object * 647 lookup_route(uint32_t fibnum, struct sockaddr_in6 *dst, struct route_in6 *ro, 648 struct ip6_pktopts *opts, uint32_t flowid) 649 { 650 struct nhop_object *nh = NULL; 651 652 /* 653 * If the next hop address for the packet is specified by the caller, 654 * use it as the gateway. 655 */ 656 if (opts && opts->ip6po_nexthop) { 657 struct route_in6 *ron = &opts->ip6po_nextroute; 658 struct sockaddr_in6 *sin6_next = satosin6(opts->ip6po_nexthop); 659 660 nh = cache_route(fibnum, sin6_next, ron, flowid); 661 662 /* 663 * The node identified by that address must be a 664 * neighbor of the sending host. 665 */ 666 if (nh != NULL && (nh->nh_flags & NHF_GATEWAY) != 0) 667 nh = NULL; 668 } else if (ro != NULL) { 669 nh = cache_route(fibnum, dst, ro, flowid); 670 if (nh == NULL) 671 return (NULL); 672 673 /* 674 * Check if the outgoing interface conflicts with 675 * the interface specified by ipi6_ifindex (if specified). 676 */ 677 struct in6_pktinfo *pi; 678 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 679 if (nh->nh_aifp->if_index != pi->ipi6_ifindex) 680 nh = NULL; 681 } 682 } 683 684 return (nh); 685 } 686 687 /* 688 * Finds outgoing nexthop or the outgoing interface for the 689 * @dstsock. 690 * Return 0 on success and stores the lookup result in @retnh and @retifp 691 */ 692 static int 693 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 694 struct ip6_moptions *mopts, struct route_in6 *ro, 695 struct ifnet **retifp, struct nhop_object **retnh, int norouteok, 696 u_int fibnum, uint32_t flowid) 697 { 698 int error = 0; 699 struct ifnet *ifp = NULL; 700 struct in6_pktinfo *pi = NULL; 701 struct in6_addr *dst = &dstsock->sin6_addr; 702 703 /* If the caller specify the outgoing interface explicitly, use it. */ 704 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 705 /* XXX boundary check is assumed to be already done. */ 706 ifp = ifnet_byindex(pi->ipi6_ifindex); 707 if (ifp != NULL && (norouteok || IN6_IS_ADDR_MULTICAST(dst))) { 708 /* 709 * we do not have to check or get the route for 710 * multicast. 711 */ 712 goto done; 713 } else 714 goto getroute; 715 } 716 /* 717 * If the destination address is a multicast address and the outgoing 718 * interface for the address is specified by the caller, use it. 719 */ 720 if (IN6_IS_ADDR_MULTICAST(dst) && 721 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 722 goto done; /* we do not need a route for multicast. */ 723 } 724 /* 725 * If destination address is LLA or link- or node-local multicast, 726 * use it's embedded scope zone id to determine outgoing interface. 727 */ 728 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) || 729 IN6_IS_ADDR_MC_NODELOCAL(dst)) { 730 uint32_t zoneid = ntohs(in6_getscope(dst)); 731 if (zoneid > 0) { 732 ifp = in6_getlinkifnet(zoneid); 733 goto done; 734 } 735 } 736 737 getroute:; 738 struct nhop_object *nh = lookup_route(fibnum, dstsock, ro, opts, flowid); 739 if (nh != NULL) { 740 *retifp = nh->nh_aifp; 741 error = 0; 742 } else { 743 *retifp = NULL; 744 IP6STAT_INC(ip6s_noroute); 745 error = EHOSTUNREACH; 746 } 747 *retnh = nh; 748 return (error); 749 750 done: 751 if (ifp == NULL) { 752 /* 753 * This can happen if the caller did not pass a cached route 754 * nor any other hints. We treat this case an error. 755 */ 756 error = EHOSTUNREACH; 757 } 758 if (error == EHOSTUNREACH) 759 IP6STAT_INC(ip6s_noroute); 760 761 *retifp = ifp; 762 *retnh = NULL; 763 764 return (error); 765 } 766 767 static int 768 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 769 struct ip6_moptions *mopts, struct ifnet **retifp, 770 struct ifnet *oifp, u_int fibnum) 771 { 772 int error; 773 struct route_in6 sro; 774 struct nhop_object *nh = NULL; 775 uint16_t nh_flags; 776 777 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__)); 778 779 bzero(&sro, sizeof(sro)); 780 nh_flags = 0; 781 782 error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0); 783 784 if (nh != NULL) 785 nh_flags = nh->nh_flags; 786 if (nh != NULL && nh == sro.ro_nh) 787 NH_FREE(nh); 788 789 if (error != 0) { 790 /* Help ND. See oifp comment in in6_selectsrc(). */ 791 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) { 792 *retifp = oifp; 793 error = 0; 794 } 795 return (error); 796 } 797 798 /* 799 * do not use a rejected or black hole route. 800 * XXX: this check should be done in the L2 output routine. 801 * However, if we skipped this check here, we'd see the following 802 * scenario: 803 * - install a rejected route for a scoped address prefix 804 * (like fe80::/10) 805 * - send a packet to a destination that matches the scoped prefix, 806 * with ambiguity about the scope zone. 807 * - pick the outgoing interface from the route, and disambiguate the 808 * scope zone with the interface. 809 * - ip6_output() would try to get another route with the "new" 810 * destination, which may be valid. 811 * - we'd see no error on output. 812 * Although this may not be very harmful, it should still be confusing. 813 * We thus reject the case here. 814 */ 815 816 if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) { 817 error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH); 818 return (error); 819 } 820 821 return (0); 822 } 823 824 /* Public wrapper function to selectroute(). */ 825 int 826 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 827 struct ip6_moptions *mopts, struct route_in6 *ro, 828 struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid) 829 { 830 MPASS(retifp != NULL); 831 MPASS(retnh != NULL); 832 833 return (selectroute(dstsock, opts, mopts, ro, retifp, 834 retnh, 0, fibnum, flowid)); 835 } 836 837 /* 838 * Default hop limit selection. The precedence is as follows: 839 * 1. Hoplimit value specified via ioctl. 840 * 2. (If the outgoing interface is detected) the current 841 * hop limit of the interface specified by router advertisement. 842 * 3. The system default hoplimit. 843 */ 844 int 845 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp) 846 { 847 848 if (inp && inp->in6p_hops >= 0) 849 return (inp->in6p_hops); 850 else if (ifp) 851 return (ND_IFINFO(ifp)->chlim); 852 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 853 struct nhop_object *nh; 854 struct in6_addr dst; 855 uint32_t fibnum, scopeid; 856 int hlim; 857 858 fibnum = inp->inp_inc.inc_fibnum; 859 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid); 860 nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0); 861 if (nh != NULL) { 862 hlim = ND_IFINFO(nh->nh_ifp)->chlim; 863 return (hlim); 864 } 865 } 866 return (V_ip6_defhlim); 867 } 868 869 void 870 addrsel_policy_init(void) 871 { 872 873 init_policy_queue(); 874 875 /* initialize the "last resort" policy */ 876 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy)); 877 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP; 878 879 if (!IS_DEFAULT_VNET(curvnet)) 880 return; 881 882 ADDRSEL_LOCK_INIT(); 883 ADDRSEL_SXLOCK_INIT(); 884 } 885 886 static struct in6_addrpolicy * 887 lookup_addrsel_policy(struct sockaddr_in6 *key) 888 { 889 struct in6_addrpolicy *match = NULL; 890 891 ADDRSEL_LOCK(); 892 match = match_addrsel_policy(key); 893 894 if (match == NULL) 895 match = &V_defaultaddrpolicy; 896 else 897 match->use++; 898 ADDRSEL_UNLOCK(); 899 900 return (match); 901 } 902 903 /* 904 * Subroutines to manage the address selection policy table via sysctl. 905 */ 906 struct walkarg { 907 struct sysctl_req *w_req; 908 }; 909 910 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS); 911 SYSCTL_DECL(_net_inet6_ip6); 912 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy, 913 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl, 914 ""); 915 916 static int 917 in6_src_sysctl(SYSCTL_HANDLER_ARGS) 918 { 919 struct walkarg w; 920 921 if (req->newptr) 922 return EPERM; 923 924 bzero(&w, sizeof(w)); 925 w.w_req = req; 926 927 return (walk_addrsel_policy(dump_addrsel_policyent, &w)); 928 } 929 930 int 931 in6_src_ioctl(u_long cmd, caddr_t data) 932 { 933 struct in6_addrpolicy ent0; 934 935 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY) 936 return (EOPNOTSUPP); /* check for safety */ 937 938 ent0 = *(struct in6_addrpolicy *)data; 939 940 if (ent0.label == ADDR_LABEL_NOTAPP) 941 return (EINVAL); 942 /* check if the prefix mask is consecutive. */ 943 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0) 944 return (EINVAL); 945 /* clear trailing garbages (if any) of the prefix address. */ 946 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr); 947 ent0.use = 0; 948 949 switch (cmd) { 950 case SIOCAADDRCTL_POLICY: 951 return (add_addrsel_policyent(&ent0)); 952 case SIOCDADDRCTL_POLICY: 953 return (delete_addrsel_policyent(&ent0)); 954 } 955 956 return (0); /* XXX: compromise compilers */ 957 } 958 959 /* 960 * The followings are implementation of the policy table using a 961 * simple tail queue. 962 * XXX such details should be hidden. 963 * XXX implementation using binary tree should be more efficient. 964 */ 965 struct addrsel_policyent { 966 TAILQ_ENTRY(addrsel_policyent) ape_entry; 967 struct in6_addrpolicy ape_policy; 968 }; 969 970 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent); 971 972 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab); 973 #define V_addrsel_policytab VNET(addrsel_policytab) 974 975 static void 976 init_policy_queue(void) 977 { 978 979 TAILQ_INIT(&V_addrsel_policytab); 980 } 981 982 static int 983 add_addrsel_policyent(struct in6_addrpolicy *newpolicy) 984 { 985 struct addrsel_policyent *new, *pol; 986 987 new = malloc(sizeof(*new), M_IFADDR, 988 M_WAITOK); 989 ADDRSEL_XLOCK(); 990 ADDRSEL_LOCK(); 991 992 /* duplication check */ 993 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 994 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr, 995 &pol->ape_policy.addr.sin6_addr) && 996 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr, 997 &pol->ape_policy.addrmask.sin6_addr)) { 998 ADDRSEL_UNLOCK(); 999 ADDRSEL_XUNLOCK(); 1000 free(new, M_IFADDR); 1001 return (EEXIST); /* or override it? */ 1002 } 1003 } 1004 1005 bzero(new, sizeof(*new)); 1006 1007 /* XXX: should validate entry */ 1008 new->ape_policy = *newpolicy; 1009 1010 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry); 1011 ADDRSEL_UNLOCK(); 1012 ADDRSEL_XUNLOCK(); 1013 1014 return (0); 1015 } 1016 1017 static int 1018 delete_addrsel_policyent(struct in6_addrpolicy *key) 1019 { 1020 struct addrsel_policyent *pol; 1021 1022 ADDRSEL_XLOCK(); 1023 ADDRSEL_LOCK(); 1024 1025 /* search for the entry in the table */ 1026 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1027 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr, 1028 &pol->ape_policy.addr.sin6_addr) && 1029 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr, 1030 &pol->ape_policy.addrmask.sin6_addr)) { 1031 break; 1032 } 1033 } 1034 if (pol == NULL) { 1035 ADDRSEL_UNLOCK(); 1036 ADDRSEL_XUNLOCK(); 1037 return (ESRCH); 1038 } 1039 1040 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry); 1041 ADDRSEL_UNLOCK(); 1042 ADDRSEL_XUNLOCK(); 1043 free(pol, M_IFADDR); 1044 1045 return (0); 1046 } 1047 1048 static int 1049 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w) 1050 { 1051 struct addrsel_policyent *pol; 1052 int error = 0; 1053 1054 ADDRSEL_SLOCK(); 1055 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1056 if ((error = (*callback)(&pol->ape_policy, w)) != 0) { 1057 ADDRSEL_SUNLOCK(); 1058 return (error); 1059 } 1060 } 1061 ADDRSEL_SUNLOCK(); 1062 return (error); 1063 } 1064 1065 static int 1066 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg) 1067 { 1068 int error = 0; 1069 struct walkarg *w = arg; 1070 1071 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol)); 1072 1073 return (error); 1074 } 1075 1076 static struct in6_addrpolicy * 1077 match_addrsel_policy(struct sockaddr_in6 *key) 1078 { 1079 struct addrsel_policyent *pent; 1080 struct in6_addrpolicy *bestpol = NULL, *pol; 1081 int matchlen, bestmatchlen = -1; 1082 u_char *mp, *ep, *k, *p, m; 1083 1084 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) { 1085 matchlen = 0; 1086 1087 pol = &pent->ape_policy; 1088 mp = (u_char *)&pol->addrmask.sin6_addr; 1089 ep = mp + 16; /* XXX: scope field? */ 1090 k = (u_char *)&key->sin6_addr; 1091 p = (u_char *)&pol->addr.sin6_addr; 1092 for (; mp < ep && *mp; mp++, k++, p++) { 1093 m = *mp; 1094 if ((*k & m) != *p) 1095 goto next; /* not match */ 1096 if (m == 0xff) /* short cut for a typical case */ 1097 matchlen += 8; 1098 else { 1099 while (m >= 0x80) { 1100 matchlen++; 1101 m <<= 1; 1102 } 1103 } 1104 } 1105 1106 /* matched. check if this is better than the current best. */ 1107 if (bestpol == NULL || 1108 matchlen > bestmatchlen) { 1109 bestpol = pol; 1110 bestmatchlen = matchlen; 1111 } 1112 1113 next: 1114 continue; 1115 } 1116 1117 return (bestpol); 1118 } 1119