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