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 63 #include "opt_inet.h" 64 #include "opt_inet6.h" 65 #include <sys/param.h> 66 #include <sys/systm.h> 67 #include <sys/lock.h> 68 #include <sys/malloc.h> 69 #include <sys/mbuf.h> 70 #include <sys/priv.h> 71 #include <sys/protosw.h> 72 #include <sys/socket.h> 73 #include <sys/socketvar.h> 74 #include <sys/sockio.h> 75 #include <sys/sysctl.h> 76 #include <sys/errno.h> 77 #include <sys/time.h> 78 #include <sys/jail.h> 79 #include <sys/kernel.h> 80 #include <sys/rmlock.h> 81 #include <sys/sx.h> 82 83 #include <net/if.h> 84 #include <net/if_var.h> 85 #include <net/if_dl.h> 86 #include <net/if_private.h> 87 #include <net/route.h> 88 #include <net/route/nhop.h> 89 #include <net/if_llatbl.h> 90 91 #include <netinet/in.h> 92 #include <netinet/in_var.h> 93 #include <netinet/in_systm.h> 94 #include <netinet/ip.h> 95 #include <netinet/in_pcb.h> 96 #include <netinet/ip_var.h> 97 #include <netinet/udp.h> 98 #include <netinet/udp_var.h> 99 100 #include <netinet6/in6_var.h> 101 #include <netinet/ip6.h> 102 #include <netinet6/in6_fib.h> 103 #include <netinet6/in6_pcb.h> 104 #include <netinet6/ip6_var.h> 105 #include <netinet6/scope6_var.h> 106 #include <netinet6/nd6.h> 107 108 static struct mtx addrsel_lock; 109 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF) 110 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock) 111 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock) 112 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED) 113 114 static struct sx addrsel_sxlock; 115 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock") 116 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock) 117 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock) 118 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock) 119 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock) 120 121 #define ADDR_LABEL_NOTAPP (-1) 122 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy); 123 #define V_defaultaddrpolicy VNET(defaultaddrpolicy) 124 125 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0; 126 127 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *, 128 struct ip6_moptions *, struct route_in6 *, struct ifnet **, 129 struct nhop_object **, int, u_int, uint32_t); 130 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *, 131 struct ip6_moptions *, struct ifnet **, 132 struct ifnet *, u_int); 133 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *, 134 struct ip6_pktopts *, struct ip6_moptions *, struct inpcb *, 135 struct ucred *, struct ifnet **, struct in6_addr *); 136 137 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *); 138 139 static void init_policy_queue(void); 140 static int add_addrsel_policyent(struct in6_addrpolicy *); 141 static int delete_addrsel_policyent(struct in6_addrpolicy *); 142 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *), 143 void *); 144 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *); 145 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *); 146 147 /* 148 * Return an IPv6 address, which is the most appropriate for a given 149 * destination and user specified options. 150 * If necessary, this function lookups the routing table and returns 151 * an entry to the caller for later use. 152 */ 153 #define REPLACE(r) do {\ 154 IP6STAT_INC2(ip6s_sources_rule, (r)); \ 155 /* { \ 156 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 157 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)); \ 158 } */ \ 159 goto replace; \ 160 } while(0) 161 #define NEXT(r) do {\ 162 /* { \ 163 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 164 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)); \ 165 } */ \ 166 goto next; /* XXX: we can't use 'continue' here */ \ 167 } while(0) 168 #define BREAK(r) do { \ 169 IP6STAT_INC2(ip6s_sources_rule, (r)); \ 170 goto out; /* XXX: we can't use 'break' here */ \ 171 } while(0) 172 173 static int 174 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock, 175 struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct inpcb *inp, 176 struct ucred *cred, struct ifnet **ifpp, struct in6_addr *srcp) 177 { 178 struct rm_priotracker in6_ifa_tracker; 179 struct in6_addr dst, tmp; 180 struct ifnet *ifp = NULL, *oifp = NULL; 181 struct in6_ifaddr *ia = NULL, *ia_best = NULL; 182 struct in6_pktinfo *pi = NULL; 183 int dst_scope = -1, best_scope = -1, best_matchlen = -1; 184 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL; 185 u_int32_t odstzone; 186 int prefer_tempaddr; 187 int error; 188 189 NET_EPOCH_ASSERT(); 190 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__)); 191 192 dst = dstsock->sin6_addr; /* make a copy for local operation */ 193 if (ifpp) { 194 /* 195 * Save a possibly passed in ifp for in6_selectsrc. Only 196 * neighbor discovery code should use this feature, where 197 * we may know the interface but not the FIB number holding 198 * the connected subnet in case someone deleted it from the 199 * default FIB and we need to check the interface. 200 */ 201 if (*ifpp != NULL) 202 oifp = *ifpp; 203 *ifpp = NULL; 204 } 205 206 /* 207 * If the source address is explicitly specified by the caller, 208 * check if the requested source address is indeed a unicast address 209 * assigned to the node, and can be used as the packet's source 210 * address. If everything is okay, use the address as source. 211 */ 212 if (opts && (pi = opts->ip6po_pktinfo) && 213 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 214 /* get the outgoing interface */ 215 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 216 fibnum)) 217 != 0) 218 return (error); 219 220 /* 221 * determine the appropriate zone id of the source based on 222 * the zone of the destination and the outgoing interface. 223 * If the specified address is ambiguous wrt the scope zone, 224 * the interface must be specified; otherwise, ifa_ifwithaddr() 225 * will fail matching the address. 226 */ 227 tmp = pi->ipi6_addr; 228 if (ifp) { 229 error = in6_setscope(&tmp, ifp, &odstzone); 230 if (error) 231 return (error); 232 } 233 if (cred != NULL && (error = prison_local_ip6(cred, 234 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) 235 return (error); 236 237 /* 238 * If IPV6_BINDANY socket option is set, we allow to specify 239 * non local addresses as source address in IPV6_PKTINFO 240 * ancillary data. 241 */ 242 if ((inp->inp_flags & INP_BINDANY) == 0) { 243 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */, false); 244 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST | 245 IN6_IFF_NOTREADY))) 246 return (EADDRNOTAVAIL); 247 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp)); 248 } else 249 bcopy(&tmp, srcp, sizeof(*srcp)); 250 pi->ipi6_addr = tmp; /* XXX: this overrides pi */ 251 if (ifpp) 252 *ifpp = ifp; 253 return (0); 254 } 255 256 /* 257 * Otherwise, if the socket has already bound the source, just use it. 258 */ 259 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) { 260 if (cred != NULL && 261 (error = prison_local_ip6(cred, &inp->in6p_laddr, 262 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0) 263 return (error); 264 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp)); 265 return (0); 266 } 267 268 /* 269 * Bypass source address selection and use the primary jail IP 270 * if requested. 271 */ 272 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp)) 273 return (0); 274 275 /* 276 * If the address is not specified, choose the best one based on 277 * the outgoing interface and the destination address. 278 */ 279 /* get the outgoing interface */ 280 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 281 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0) 282 return (error); 283 284 #ifdef DIAGNOSTIC 285 if (ifp == NULL) /* this should not happen */ 286 panic("in6_selectsrc: NULL ifp"); 287 #endif 288 error = in6_setscope(&dst, ifp, &odstzone); 289 if (error) 290 return (error); 291 292 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 293 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 294 int new_scope = -1, new_matchlen = -1; 295 struct in6_addrpolicy *new_policy = NULL; 296 u_int32_t srczone, osrczone, dstzone; 297 struct in6_addr src; 298 struct ifnet *ifp1 = ia->ia_ifp; 299 300 /* 301 * We'll never take an address that breaks the scope zone 302 * of the destination. We also skip an address if its zone 303 * does not contain the outgoing interface. 304 * XXX: we should probably use sin6_scope_id here. 305 */ 306 if (in6_setscope(&dst, ifp1, &dstzone) || 307 odstzone != dstzone) { 308 continue; 309 } 310 src = ia->ia_addr.sin6_addr; 311 if (in6_setscope(&src, ifp, &osrczone) || 312 in6_setscope(&src, ifp1, &srczone) || 313 osrczone != srczone) { 314 continue; 315 } 316 317 /* avoid unusable addresses */ 318 if ((ia->ia6_flags & 319 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { 320 continue; 321 } 322 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) 323 continue; 324 325 /* If jailed only take addresses of the jail into account. */ 326 if (cred != NULL && 327 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0) 328 continue; 329 330 /* Rule 1: Prefer same address */ 331 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { 332 ia_best = ia; 333 BREAK(1); /* there should be no better candidate */ 334 } 335 336 if (ia_best == NULL) 337 REPLACE(0); 338 339 /* Rule 2: Prefer appropriate scope */ 340 if (dst_scope < 0) 341 dst_scope = in6_addrscope(&dst); 342 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); 343 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { 344 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) 345 REPLACE(2); 346 NEXT(2); 347 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { 348 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) 349 NEXT(2); 350 REPLACE(2); 351 } 352 353 /* 354 * Rule 3: Avoid deprecated addresses. Note that the case of 355 * !ip6_use_deprecated is already rejected above. 356 */ 357 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) 358 NEXT(3); 359 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) 360 REPLACE(3); 361 362 /* Rule 4: Prefer home addresses */ 363 /* 364 * XXX: This is a TODO. We should probably merge the MIP6 365 * case above. 366 */ 367 368 /* Rule 5: Prefer outgoing interface */ 369 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) { 370 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) 371 NEXT(5); 372 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) 373 REPLACE(5); 374 } 375 376 /* 377 * Rule 6: Prefer matching label 378 * Note that best_policy should be non-NULL here. 379 */ 380 if (dst_policy == NULL) 381 dst_policy = lookup_addrsel_policy(dstsock); 382 if (dst_policy->label != ADDR_LABEL_NOTAPP) { 383 new_policy = lookup_addrsel_policy(&ia->ia_addr); 384 if (dst_policy->label == best_policy->label && 385 dst_policy->label != new_policy->label) 386 NEXT(6); 387 if (dst_policy->label != best_policy->label && 388 dst_policy->label == new_policy->label) 389 REPLACE(6); 390 } 391 392 /* 393 * Rule 7: Prefer public addresses. 394 * We allow users to reverse the logic by configuring 395 * a sysctl variable, so that privacy conscious users can 396 * always prefer temporary addresses. 397 */ 398 if (opts == NULL || 399 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { 400 prefer_tempaddr = V_ip6_prefer_tempaddr; 401 } else if (opts->ip6po_prefer_tempaddr == 402 IP6PO_TEMPADDR_NOTPREFER) { 403 prefer_tempaddr = 0; 404 } else 405 prefer_tempaddr = 1; 406 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 407 (ia->ia6_flags & IN6_IFF_TEMPORARY)) { 408 if (prefer_tempaddr) 409 REPLACE(7); 410 else 411 NEXT(7); 412 } 413 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 414 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { 415 if (prefer_tempaddr) 416 NEXT(7); 417 else 418 REPLACE(7); 419 } 420 421 /* 422 * Rule 8: prefer addresses on alive interfaces. 423 * This is a KAME specific rule. 424 */ 425 if ((ia_best->ia_ifp->if_flags & IFF_UP) && 426 !(ia->ia_ifp->if_flags & IFF_UP)) 427 NEXT(8); 428 if (!(ia_best->ia_ifp->if_flags & IFF_UP) && 429 (ia->ia_ifp->if_flags & IFF_UP)) 430 REPLACE(8); 431 432 /* 433 * Rule 9: prefer address with better virtual status. 434 */ 435 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa)) 436 REPLACE(9); 437 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa)) 438 NEXT(9); 439 440 /* 441 * Rule 10: prefer address with `prefer_source' flag. 442 */ 443 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 && 444 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0) 445 REPLACE(10); 446 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 && 447 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0) 448 NEXT(10); 449 450 /* 451 * Rule 14: Use longest matching prefix. 452 * Note: in the address selection draft, this rule is 453 * documented as "Rule 8". However, since it is also 454 * documented that this rule can be overridden, we assign 455 * a large number so that it is easy to assign smaller numbers 456 * to more preferred rules. 457 */ 458 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); 459 if (best_matchlen < new_matchlen) 460 REPLACE(14); 461 if (new_matchlen < best_matchlen) 462 NEXT(14); 463 464 /* Rule 15 is reserved. */ 465 466 /* 467 * Last resort: just keep the current candidate. 468 * Or, do we need more rules? 469 */ 470 continue; 471 472 replace: 473 ia_best = ia; 474 best_scope = (new_scope >= 0 ? new_scope : 475 in6_addrscope(&ia_best->ia_addr.sin6_addr)); 476 best_policy = (new_policy ? new_policy : 477 lookup_addrsel_policy(&ia_best->ia_addr)); 478 best_matchlen = (new_matchlen >= 0 ? new_matchlen : 479 in6_matchlen(&ia_best->ia_addr.sin6_addr, 480 &dst)); 481 482 next: 483 continue; 484 485 out: 486 break; 487 } 488 489 if ((ia = ia_best) == NULL) { 490 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 491 IP6STAT_INC(ip6s_sources_none); 492 return (EADDRNOTAVAIL); 493 } 494 495 /* 496 * At this point at least one of the addresses belonged to the jail 497 * but it could still be, that we want to further restrict it, e.g. 498 * theoratically IN6_IS_ADDR_LOOPBACK. 499 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore. 500 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should 501 * let all others previously selected pass. 502 * Use tmp to not change ::1 on lo0 to the primary jail address. 503 */ 504 tmp = ia->ia_addr.sin6_addr; 505 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL && 506 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) { 507 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 508 IP6STAT_INC(ip6s_sources_none); 509 return (EADDRNOTAVAIL); 510 } 511 512 if (ifpp) 513 *ifpp = ifp; 514 515 bcopy(&tmp, srcp, sizeof(*srcp)); 516 if (ia->ia_ifp == ifp) 517 IP6STAT_INC2(ip6s_sources_sameif, best_scope); 518 else 519 IP6STAT_INC2(ip6s_sources_otherif, best_scope); 520 if (dst_scope == best_scope) 521 IP6STAT_INC2(ip6s_sources_samescope, best_scope); 522 else 523 IP6STAT_INC2(ip6s_sources_otherscope, best_scope); 524 if (IFA6_IS_DEPRECATED(ia)) 525 IP6STAT_INC2(ip6s_sources_deprecated, best_scope); 526 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 527 return (0); 528 } 529 530 /* 531 * Select source address based on @inp, @dstsock and @opts. 532 * Stores selected address to @srcp. If @scope_ambiguous is set, 533 * embed scope from selected outgoing interface. If @hlim pointer 534 * is provided, stores calculated hop limit there. 535 * Returns 0 on success. 536 */ 537 int 538 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 539 struct inpcb *inp, struct ucred *cred, int scope_ambiguous, 540 struct in6_addr *srcp, int *hlim) 541 { 542 struct ifnet *retifp; 543 uint32_t fibnum; 544 int error; 545 546 INP_LOCK_ASSERT(inp); 547 548 fibnum = inp->inp_inc.inc_fibnum; 549 retifp = NULL; 550 551 error = in6_selectsrc(fibnum, dstsock, opts, inp->in6p_moptions, 552 inp, cred, &retifp, srcp); 553 if (error != 0) 554 return (error); 555 556 if (hlim != NULL) 557 *hlim = in6_selecthlim(inp, retifp); 558 559 if (retifp == NULL || scope_ambiguous == 0) 560 return (0); 561 562 /* 563 * Application should provide a proper zone ID or the use of 564 * default zone IDs should be enabled. Unfortunately, some 565 * applications do not behave as it should, so we need a 566 * workaround. Even if an appropriate ID is not determined 567 * (when it's required), if we can determine the outgoing 568 * interface. determine the zone ID based on the interface. 569 */ 570 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL); 571 572 return (error); 573 } 574 575 /* 576 * Select source address based on @fibnum, @dst and @scopeid. 577 * Stores selected address to @srcp. 578 * Returns 0 on success. 579 * 580 * Used by non-socket based consumers 581 */ 582 int 583 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst, 584 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp, 585 int *hlim) 586 { 587 struct ifnet *retifp; 588 struct sockaddr_in6 dst_sa; 589 int error; 590 591 retifp = ifp; 592 bzero(&dst_sa, sizeof(dst_sa)); 593 dst_sa.sin6_family = AF_INET6; 594 dst_sa.sin6_len = sizeof(dst_sa); 595 dst_sa.sin6_addr = *dst; 596 dst_sa.sin6_scope_id = scopeid; 597 sa6_embedscope(&dst_sa, 0); 598 599 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL, 600 NULL, NULL, &retifp, srcp); 601 if (hlim != NULL) 602 *hlim = in6_selecthlim(NULL, retifp); 603 604 return (error); 605 } 606 607 /* 608 * Select source address based on @fibnum, @dst and @mopts. 609 * Stores selected address to @srcp. 610 * Returns 0 on success. 611 * 612 * Used by non-socket based consumers (ND code mostly) 613 */ 614 int 615 in6_selectsrc_nbr(uint32_t fibnum, const struct in6_addr *dst, 616 struct ip6_moptions *mopts, struct ifnet *ifp, struct in6_addr *srcp) 617 { 618 struct sockaddr_in6 dst_sa; 619 struct ifnet *retifp; 620 int error; 621 622 retifp = ifp; 623 bzero(&dst_sa, sizeof(dst_sa)); 624 dst_sa.sin6_family = AF_INET6; 625 dst_sa.sin6_len = sizeof(dst_sa); 626 dst_sa.sin6_addr = *dst; 627 dst_sa.sin6_scope_id = ntohs(in6_getscope(dst)); 628 sa6_embedscope(&dst_sa, 0); 629 630 error = in6_selectsrc(fibnum, &dst_sa, NULL, mopts, 631 NULL, NULL, &retifp, srcp); 632 return (error); 633 } 634 635 static struct nhop_object * 636 cache_route(uint32_t fibnum, const struct sockaddr_in6 *dst, struct route_in6 *ro, 637 uint32_t flowid) 638 { 639 /* 640 * Use a cached route if it exists and is valid, else try to allocate 641 * a new one. Note that we should check the address family of the 642 * cached destination, in case of sharing the cache with IPv4. 643 * Assumes that 'struct route_in6' is exclusively locked. 644 */ 645 if (ro->ro_nh != NULL && ( 646 !NH_IS_VALID(ro->ro_nh) || ro->ro_dst.sin6_family != AF_INET6 || 647 !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &dst->sin6_addr))) 648 RO_NHFREE(ro); 649 650 if (ro->ro_nh == NULL) { 651 ro->ro_dst = *dst; 652 653 const struct in6_addr *paddr; 654 struct in6_addr unscoped_addr; 655 uint32_t scopeid = 0; 656 if (IN6_IS_SCOPE_LINKLOCAL(&dst->sin6_addr)) { 657 in6_splitscope(&dst->sin6_addr, &unscoped_addr, &scopeid); 658 paddr = &unscoped_addr; 659 } else 660 paddr = &dst->sin6_addr; 661 ro->ro_nh = fib6_lookup(fibnum, paddr, scopeid, NHR_REF, flowid); 662 } 663 return (ro->ro_nh); 664 } 665 666 static struct nhop_object * 667 lookup_route(uint32_t fibnum, struct sockaddr_in6 *dst, struct route_in6 *ro, 668 struct ip6_pktopts *opts, uint32_t flowid) 669 { 670 struct nhop_object *nh = NULL; 671 672 /* 673 * If the next hop address for the packet is specified by the caller, 674 * use it as the gateway. 675 */ 676 if (opts && opts->ip6po_nexthop) { 677 struct route_in6 *ron = &opts->ip6po_nextroute; 678 struct sockaddr_in6 *sin6_next = satosin6(opts->ip6po_nexthop); 679 680 nh = cache_route(fibnum, sin6_next, ron, flowid); 681 682 /* 683 * The node identified by that address must be a 684 * neighbor of the sending host. 685 */ 686 if (nh != NULL && (nh->nh_flags & NHF_GATEWAY) != 0) 687 nh = NULL; 688 } else if (ro != NULL) { 689 nh = cache_route(fibnum, dst, ro, flowid); 690 if (nh == NULL) 691 return (NULL); 692 693 /* 694 * Check if the outgoing interface conflicts with 695 * the interface specified by ipi6_ifindex (if specified). 696 */ 697 struct in6_pktinfo *pi; 698 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 699 if (nh->nh_aifp->if_index != pi->ipi6_ifindex) 700 nh = NULL; 701 } 702 } 703 704 return (nh); 705 } 706 707 /* 708 * Finds outgoing nexthop or the outgoing interface for the 709 * @dstsock. 710 * Return 0 on success and stores the lookup result in @retnh and @retifp 711 */ 712 static int 713 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 714 struct ip6_moptions *mopts, struct route_in6 *ro, 715 struct ifnet **retifp, struct nhop_object **retnh, int norouteok, 716 u_int fibnum, uint32_t flowid) 717 { 718 int error = 0; 719 struct ifnet *ifp = NULL; 720 struct in6_pktinfo *pi = NULL; 721 struct in6_addr *dst = &dstsock->sin6_addr; 722 723 /* If the caller specify the outgoing interface explicitly, use it. */ 724 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 725 /* XXX boundary check is assumed to be already done. */ 726 ifp = ifnet_byindex(pi->ipi6_ifindex); 727 if (ifp != NULL && (norouteok || IN6_IS_ADDR_MULTICAST(dst))) { 728 /* 729 * we do not have to check or get the route for 730 * multicast. 731 */ 732 goto done; 733 } else 734 goto getroute; 735 } 736 /* 737 * If the destination address is a multicast address and the outgoing 738 * interface for the address is specified by the caller, use it. 739 */ 740 if (IN6_IS_ADDR_MULTICAST(dst) && 741 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 742 goto done; /* we do not need a route for multicast. */ 743 } 744 /* 745 * If destination address is LLA or link- or node-local multicast, 746 * use it's embedded scope zone id to determine outgoing interface. 747 */ 748 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) || 749 IN6_IS_ADDR_MC_NODELOCAL(dst)) { 750 uint32_t zoneid = ntohs(in6_getscope(dst)); 751 if (zoneid > 0) { 752 ifp = in6_getlinkifnet(zoneid); 753 goto done; 754 } 755 } 756 757 getroute:; 758 struct nhop_object *nh = lookup_route(fibnum, dstsock, ro, opts, flowid); 759 if (nh != NULL) { 760 *retifp = nh->nh_aifp; 761 error = 0; 762 } else { 763 *retifp = NULL; 764 IP6STAT_INC(ip6s_noroute); 765 error = EHOSTUNREACH; 766 } 767 *retnh = nh; 768 return (error); 769 770 done: 771 if (ifp == NULL) { 772 /* 773 * This can happen if the caller did not pass a cached route 774 * nor any other hints. We treat this case an error. 775 */ 776 error = EHOSTUNREACH; 777 } 778 if (error == EHOSTUNREACH) 779 IP6STAT_INC(ip6s_noroute); 780 781 *retifp = ifp; 782 *retnh = NULL; 783 784 return (error); 785 } 786 787 static int 788 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 789 struct ip6_moptions *mopts, struct ifnet **retifp, 790 struct ifnet *oifp, u_int fibnum) 791 { 792 int error; 793 struct route_in6 sro; 794 struct nhop_object *nh = NULL; 795 uint16_t nh_flags; 796 797 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__)); 798 799 bzero(&sro, sizeof(sro)); 800 nh_flags = 0; 801 802 error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0); 803 804 if (nh != NULL) 805 nh_flags = nh->nh_flags; 806 if (nh != NULL && nh == sro.ro_nh) 807 NH_FREE(nh); 808 809 if (error != 0) { 810 /* Help ND. See oifp comment in in6_selectsrc(). */ 811 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) { 812 *retifp = oifp; 813 error = 0; 814 } 815 return (error); 816 } 817 818 /* 819 * do not use a rejected or black hole route. 820 * XXX: this check should be done in the L2 output routine. 821 * However, if we skipped this check here, we'd see the following 822 * scenario: 823 * - install a rejected route for a scoped address prefix 824 * (like fe80::/10) 825 * - send a packet to a destination that matches the scoped prefix, 826 * with ambiguity about the scope zone. 827 * - pick the outgoing interface from the route, and disambiguate the 828 * scope zone with the interface. 829 * - ip6_output() would try to get another route with the "new" 830 * destination, which may be valid. 831 * - we'd see no error on output. 832 * Although this may not be very harmful, it should still be confusing. 833 * We thus reject the case here. 834 */ 835 836 if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) { 837 error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH); 838 return (error); 839 } 840 841 return (0); 842 } 843 844 /* Public wrapper function to selectroute(). */ 845 int 846 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 847 struct ip6_moptions *mopts, struct route_in6 *ro, 848 struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid) 849 { 850 MPASS(retifp != NULL); 851 MPASS(retnh != NULL); 852 853 return (selectroute(dstsock, opts, mopts, ro, retifp, 854 retnh, 0, fibnum, flowid)); 855 } 856 857 /* 858 * Default hop limit selection. The precedence is as follows: 859 * 1. Hoplimit value specified via ioctl. 860 * 2. (If the outgoing interface is detected) the current 861 * hop limit of the interface specified by router advertisement. 862 * 3. The system default hoplimit. 863 */ 864 int 865 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp) 866 { 867 868 if (inp && inp->in6p_hops >= 0) 869 return (inp->in6p_hops); 870 else if (ifp) 871 return (ND_IFINFO(ifp)->chlim); 872 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 873 struct nhop_object *nh; 874 struct in6_addr dst; 875 uint32_t fibnum, scopeid; 876 int hlim; 877 878 fibnum = inp->inp_inc.inc_fibnum; 879 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid); 880 nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0); 881 if (nh != NULL) { 882 hlim = ND_IFINFO(nh->nh_ifp)->chlim; 883 return (hlim); 884 } 885 } 886 return (V_ip6_defhlim); 887 } 888 889 void 890 addrsel_policy_init(void) 891 { 892 893 init_policy_queue(); 894 895 /* initialize the "last resort" policy */ 896 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy)); 897 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP; 898 899 if (!IS_DEFAULT_VNET(curvnet)) 900 return; 901 902 ADDRSEL_LOCK_INIT(); 903 ADDRSEL_SXLOCK_INIT(); 904 } 905 906 static struct in6_addrpolicy * 907 lookup_addrsel_policy(struct sockaddr_in6 *key) 908 { 909 struct in6_addrpolicy *match = NULL; 910 911 ADDRSEL_LOCK(); 912 match = match_addrsel_policy(key); 913 914 if (match == NULL) 915 match = &V_defaultaddrpolicy; 916 else 917 match->use++; 918 ADDRSEL_UNLOCK(); 919 920 return (match); 921 } 922 923 /* 924 * Subroutines to manage the address selection policy table via sysctl. 925 */ 926 struct walkarg { 927 struct sysctl_req *w_req; 928 }; 929 930 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS); 931 SYSCTL_DECL(_net_inet6_ip6); 932 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy, 933 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl, 934 ""); 935 936 static int 937 in6_src_sysctl(SYSCTL_HANDLER_ARGS) 938 { 939 struct walkarg w; 940 941 if (req->newptr) 942 return EPERM; 943 944 bzero(&w, sizeof(w)); 945 w.w_req = req; 946 947 return (walk_addrsel_policy(dump_addrsel_policyent, &w)); 948 } 949 950 int 951 in6_src_ioctl(u_long cmd, caddr_t data) 952 { 953 struct in6_addrpolicy ent0; 954 955 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY) 956 return (EOPNOTSUPP); /* check for safety */ 957 958 ent0 = *(struct in6_addrpolicy *)data; 959 960 if (ent0.label == ADDR_LABEL_NOTAPP) 961 return (EINVAL); 962 /* check if the prefix mask is consecutive. */ 963 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0) 964 return (EINVAL); 965 /* clear trailing garbages (if any) of the prefix address. */ 966 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr); 967 ent0.use = 0; 968 969 switch (cmd) { 970 case SIOCAADDRCTL_POLICY: 971 return (add_addrsel_policyent(&ent0)); 972 case SIOCDADDRCTL_POLICY: 973 return (delete_addrsel_policyent(&ent0)); 974 } 975 976 return (0); /* XXX: compromise compilers */ 977 } 978 979 /* 980 * The followings are implementation of the policy table using a 981 * simple tail queue. 982 * XXX such details should be hidden. 983 * XXX implementation using binary tree should be more efficient. 984 */ 985 struct addrsel_policyent { 986 TAILQ_ENTRY(addrsel_policyent) ape_entry; 987 struct in6_addrpolicy ape_policy; 988 }; 989 990 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent); 991 992 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab); 993 #define V_addrsel_policytab VNET(addrsel_policytab) 994 995 static void 996 init_policy_queue(void) 997 { 998 999 TAILQ_INIT(&V_addrsel_policytab); 1000 } 1001 1002 static int 1003 add_addrsel_policyent(struct in6_addrpolicy *newpolicy) 1004 { 1005 struct addrsel_policyent *new, *pol; 1006 1007 new = malloc(sizeof(*new), M_IFADDR, 1008 M_WAITOK); 1009 ADDRSEL_XLOCK(); 1010 ADDRSEL_LOCK(); 1011 1012 /* duplication check */ 1013 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1014 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr, 1015 &pol->ape_policy.addr.sin6_addr) && 1016 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr, 1017 &pol->ape_policy.addrmask.sin6_addr)) { 1018 ADDRSEL_UNLOCK(); 1019 ADDRSEL_XUNLOCK(); 1020 free(new, M_IFADDR); 1021 return (EEXIST); /* or override it? */ 1022 } 1023 } 1024 1025 bzero(new, sizeof(*new)); 1026 1027 /* XXX: should validate entry */ 1028 new->ape_policy = *newpolicy; 1029 1030 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry); 1031 ADDRSEL_UNLOCK(); 1032 ADDRSEL_XUNLOCK(); 1033 1034 return (0); 1035 } 1036 1037 static int 1038 delete_addrsel_policyent(struct in6_addrpolicy *key) 1039 { 1040 struct addrsel_policyent *pol; 1041 1042 ADDRSEL_XLOCK(); 1043 ADDRSEL_LOCK(); 1044 1045 /* search for the entry in the table */ 1046 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1047 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr, 1048 &pol->ape_policy.addr.sin6_addr) && 1049 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr, 1050 &pol->ape_policy.addrmask.sin6_addr)) { 1051 break; 1052 } 1053 } 1054 if (pol == NULL) { 1055 ADDRSEL_UNLOCK(); 1056 ADDRSEL_XUNLOCK(); 1057 return (ESRCH); 1058 } 1059 1060 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry); 1061 ADDRSEL_UNLOCK(); 1062 ADDRSEL_XUNLOCK(); 1063 free(pol, M_IFADDR); 1064 1065 return (0); 1066 } 1067 1068 static int 1069 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w) 1070 { 1071 struct addrsel_policyent *pol; 1072 int error = 0; 1073 1074 ADDRSEL_SLOCK(); 1075 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1076 if ((error = (*callback)(&pol->ape_policy, w)) != 0) { 1077 ADDRSEL_SUNLOCK(); 1078 return (error); 1079 } 1080 } 1081 ADDRSEL_SUNLOCK(); 1082 return (error); 1083 } 1084 1085 static int 1086 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg) 1087 { 1088 int error = 0; 1089 struct walkarg *w = arg; 1090 1091 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol)); 1092 1093 return (error); 1094 } 1095 1096 static struct in6_addrpolicy * 1097 match_addrsel_policy(struct sockaddr_in6 *key) 1098 { 1099 struct addrsel_policyent *pent; 1100 struct in6_addrpolicy *bestpol = NULL, *pol; 1101 int matchlen, bestmatchlen = -1; 1102 u_char *mp, *ep, *k, *p, m; 1103 1104 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) { 1105 matchlen = 0; 1106 1107 pol = &pent->ape_policy; 1108 mp = (u_char *)&pol->addrmask.sin6_addr; 1109 ep = mp + 16; /* XXX: scope field? */ 1110 k = (u_char *)&key->sin6_addr; 1111 p = (u_char *)&pol->addr.sin6_addr; 1112 for (; mp < ep && *mp; mp++, k++, p++) { 1113 m = *mp; 1114 if ((*k & m) != *p) 1115 goto next; /* not match */ 1116 if (m == 0xff) /* short cut for a typical case */ 1117 matchlen += 8; 1118 else { 1119 while (m >= 0x80) { 1120 matchlen++; 1121 m <<= 1; 1122 } 1123 } 1124 } 1125 1126 /* matched. check if this is better than the current best. */ 1127 if (bestpol == NULL || 1128 matchlen > bestmatchlen) { 1129 bestpol = pol; 1130 bestmatchlen = matchlen; 1131 } 1132 1133 next: 1134 continue; 1135 } 1136 1137 return (bestpol); 1138 } 1139