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 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__)); 195 196 dst = dstsock->sin6_addr; /* make a copy for local operation */ 197 if (ifpp) { 198 /* 199 * Save a possibly passed in ifp for in6_selectsrc. Only 200 * neighbor discovery code should use this feature, where 201 * we may know the interface but not the FIB number holding 202 * the connected subnet in case someone deleted it from the 203 * default FIB and we need to check the interface. 204 */ 205 if (*ifpp != NULL) 206 oifp = *ifpp; 207 *ifpp = NULL; 208 } 209 210 if (inp != NULL) { 211 INP_LOCK_ASSERT(inp); 212 mopts = inp->in6p_moptions; 213 } else { 214 mopts = NULL; 215 } 216 217 /* 218 * If the source address is explicitly specified by the caller, 219 * check if the requested source address is indeed a unicast address 220 * assigned to the node, and can be used as the packet's source 221 * address. If everything is okay, use the address as source. 222 */ 223 if (opts && (pi = opts->ip6po_pktinfo) && 224 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 225 /* get the outgoing interface */ 226 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 227 fibnum)) 228 != 0) 229 return (error); 230 231 /* 232 * determine the appropriate zone id of the source based on 233 * the zone of the destination and the outgoing interface. 234 * If the specified address is ambiguous wrt the scope zone, 235 * the interface must be specified; otherwise, ifa_ifwithaddr() 236 * will fail matching the address. 237 */ 238 tmp = pi->ipi6_addr; 239 if (ifp) { 240 error = in6_setscope(&tmp, ifp, &odstzone); 241 if (error) 242 return (error); 243 } 244 if (cred != NULL && (error = prison_local_ip6(cred, 245 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) 246 return (error); 247 248 /* 249 * If IPV6_BINDANY socket option is set, we allow to specify 250 * non local addresses as source address in IPV6_PKTINFO 251 * ancillary data. 252 */ 253 if ((inp->inp_flags & INP_BINDANY) == 0) { 254 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */); 255 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST | 256 IN6_IFF_NOTREADY))) { 257 if (ia != NULL) 258 ifa_free(&ia->ia_ifa); 259 return (EADDRNOTAVAIL); 260 } 261 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp)); 262 ifa_free(&ia->ia_ifa); 263 } else 264 bcopy(&tmp, srcp, sizeof(*srcp)); 265 pi->ipi6_addr = tmp; /* XXX: this overrides pi */ 266 if (ifpp) 267 *ifpp = ifp; 268 return (0); 269 } 270 271 /* 272 * Otherwise, if the socket has already bound the source, just use it. 273 */ 274 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) { 275 if (cred != NULL && 276 (error = prison_local_ip6(cred, &inp->in6p_laddr, 277 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0) 278 return (error); 279 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp)); 280 return (0); 281 } 282 283 /* 284 * Bypass source address selection and use the primary jail IP 285 * if requested. 286 */ 287 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp)) 288 return (0); 289 290 /* 291 * If the address is not specified, choose the best one based on 292 * the outgoing interface and the destination address. 293 */ 294 /* get the outgoing interface */ 295 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 296 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0) 297 return (error); 298 299 #ifdef DIAGNOSTIC 300 if (ifp == NULL) /* this should not happen */ 301 panic("in6_selectsrc: NULL ifp"); 302 #endif 303 error = in6_setscope(&dst, ifp, &odstzone); 304 if (error) 305 return (error); 306 307 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 308 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 309 int new_scope = -1, new_matchlen = -1; 310 struct in6_addrpolicy *new_policy = NULL; 311 u_int32_t srczone, osrczone, dstzone; 312 struct in6_addr src; 313 struct ifnet *ifp1 = ia->ia_ifp; 314 315 /* 316 * We'll never take an address that breaks the scope zone 317 * of the destination. We also skip an address if its zone 318 * does not contain the outgoing interface. 319 * XXX: we should probably use sin6_scope_id here. 320 */ 321 if (in6_setscope(&dst, ifp1, &dstzone) || 322 odstzone != dstzone) { 323 continue; 324 } 325 src = ia->ia_addr.sin6_addr; 326 if (in6_setscope(&src, ifp, &osrczone) || 327 in6_setscope(&src, ifp1, &srczone) || 328 osrczone != srczone) { 329 continue; 330 } 331 332 /* avoid unusable addresses */ 333 if ((ia->ia6_flags & 334 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { 335 continue; 336 } 337 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) 338 continue; 339 340 /* If jailed only take addresses of the jail into account. */ 341 if (cred != NULL && 342 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0) 343 continue; 344 345 /* Rule 1: Prefer same address */ 346 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { 347 ia_best = ia; 348 BREAK(1); /* there should be no better candidate */ 349 } 350 351 if (ia_best == NULL) 352 REPLACE(0); 353 354 /* Rule 2: Prefer appropriate scope */ 355 if (dst_scope < 0) 356 dst_scope = in6_addrscope(&dst); 357 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); 358 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { 359 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) 360 REPLACE(2); 361 NEXT(2); 362 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { 363 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) 364 NEXT(2); 365 REPLACE(2); 366 } 367 368 /* 369 * Rule 3: Avoid deprecated addresses. Note that the case of 370 * !ip6_use_deprecated is already rejected above. 371 */ 372 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) 373 NEXT(3); 374 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) 375 REPLACE(3); 376 377 /* Rule 4: Prefer home addresses */ 378 /* 379 * XXX: This is a TODO. We should probably merge the MIP6 380 * case above. 381 */ 382 383 /* Rule 5: Prefer outgoing interface */ 384 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) { 385 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) 386 NEXT(5); 387 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) 388 REPLACE(5); 389 } 390 391 /* 392 * Rule 6: Prefer matching label 393 * Note that best_policy should be non-NULL here. 394 */ 395 if (dst_policy == NULL) 396 dst_policy = lookup_addrsel_policy(dstsock); 397 if (dst_policy->label != ADDR_LABEL_NOTAPP) { 398 new_policy = lookup_addrsel_policy(&ia->ia_addr); 399 if (dst_policy->label == best_policy->label && 400 dst_policy->label != new_policy->label) 401 NEXT(6); 402 if (dst_policy->label != best_policy->label && 403 dst_policy->label == new_policy->label) 404 REPLACE(6); 405 } 406 407 /* 408 * Rule 7: Prefer public addresses. 409 * We allow users to reverse the logic by configuring 410 * a sysctl variable, so that privacy conscious users can 411 * always prefer temporary addresses. 412 */ 413 if (opts == NULL || 414 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { 415 prefer_tempaddr = V_ip6_prefer_tempaddr; 416 } else if (opts->ip6po_prefer_tempaddr == 417 IP6PO_TEMPADDR_NOTPREFER) { 418 prefer_tempaddr = 0; 419 } else 420 prefer_tempaddr = 1; 421 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 422 (ia->ia6_flags & IN6_IFF_TEMPORARY)) { 423 if (prefer_tempaddr) 424 REPLACE(7); 425 else 426 NEXT(7); 427 } 428 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 429 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { 430 if (prefer_tempaddr) 431 NEXT(7); 432 else 433 REPLACE(7); 434 } 435 436 /* 437 * Rule 8: prefer addresses on alive interfaces. 438 * This is a KAME specific rule. 439 */ 440 if ((ia_best->ia_ifp->if_flags & IFF_UP) && 441 !(ia->ia_ifp->if_flags & IFF_UP)) 442 NEXT(8); 443 if (!(ia_best->ia_ifp->if_flags & IFF_UP) && 444 (ia->ia_ifp->if_flags & IFF_UP)) 445 REPLACE(8); 446 447 /* 448 * Rule 9: prefer address with better virtual status. 449 */ 450 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa)) 451 REPLACE(9); 452 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa)) 453 NEXT(9); 454 455 /* 456 * Rule 10: prefer address with `prefer_source' flag. 457 */ 458 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 && 459 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0) 460 REPLACE(10); 461 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 && 462 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0) 463 NEXT(10); 464 465 /* 466 * Rule 14: Use longest matching prefix. 467 * Note: in the address selection draft, this rule is 468 * documented as "Rule 8". However, since it is also 469 * documented that this rule can be overridden, we assign 470 * a large number so that it is easy to assign smaller numbers 471 * to more preferred rules. 472 */ 473 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); 474 if (best_matchlen < new_matchlen) 475 REPLACE(14); 476 if (new_matchlen < best_matchlen) 477 NEXT(14); 478 479 /* Rule 15 is reserved. */ 480 481 /* 482 * Last resort: just keep the current candidate. 483 * Or, do we need more rules? 484 */ 485 continue; 486 487 replace: 488 ia_best = ia; 489 best_scope = (new_scope >= 0 ? new_scope : 490 in6_addrscope(&ia_best->ia_addr.sin6_addr)); 491 best_policy = (new_policy ? new_policy : 492 lookup_addrsel_policy(&ia_best->ia_addr)); 493 best_matchlen = (new_matchlen >= 0 ? new_matchlen : 494 in6_matchlen(&ia_best->ia_addr.sin6_addr, 495 &dst)); 496 497 next: 498 continue; 499 500 out: 501 break; 502 } 503 504 if ((ia = ia_best) == NULL) { 505 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 506 IP6STAT_INC(ip6s_sources_none); 507 return (EADDRNOTAVAIL); 508 } 509 510 /* 511 * At this point at least one of the addresses belonged to the jail 512 * but it could still be, that we want to further restrict it, e.g. 513 * theoratically IN6_IS_ADDR_LOOPBACK. 514 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore. 515 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should 516 * let all others previously selected pass. 517 * Use tmp to not change ::1 on lo0 to the primary jail address. 518 */ 519 tmp = ia->ia_addr.sin6_addr; 520 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL && 521 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) { 522 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 523 IP6STAT_INC(ip6s_sources_none); 524 return (EADDRNOTAVAIL); 525 } 526 527 if (ifpp) 528 *ifpp = ifp; 529 530 bcopy(&tmp, srcp, sizeof(*srcp)); 531 if (ia->ia_ifp == ifp) 532 IP6STAT_INC(ip6s_sources_sameif[best_scope]); 533 else 534 IP6STAT_INC(ip6s_sources_otherif[best_scope]); 535 if (dst_scope == best_scope) 536 IP6STAT_INC(ip6s_sources_samescope[best_scope]); 537 else 538 IP6STAT_INC(ip6s_sources_otherscope[best_scope]); 539 if (IFA6_IS_DEPRECATED(ia)) 540 IP6STAT_INC(ip6s_sources_deprecated[best_scope]); 541 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 542 return (0); 543 } 544 545 /* 546 * Select source address based on @inp, @dstsock and @opts. 547 * Stores selected address to @srcp. If @scope_ambiguous is set, 548 * embed scope from selected outgoing interface. If @hlim pointer 549 * is provided, stores calculated hop limit there. 550 * Returns 0 on success. 551 */ 552 int 553 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 554 struct inpcb *inp, struct ucred *cred, int scope_ambiguous, 555 struct in6_addr *srcp, int *hlim) 556 { 557 struct ifnet *retifp; 558 uint32_t fibnum; 559 int error; 560 561 fibnum = inp->inp_inc.inc_fibnum; 562 retifp = NULL; 563 564 error = in6_selectsrc(fibnum, dstsock, opts, inp, cred, &retifp, srcp); 565 if (error != 0) 566 return (error); 567 568 if (hlim != NULL) 569 *hlim = in6_selecthlim(inp, retifp); 570 571 if (retifp == NULL || scope_ambiguous == 0) 572 return (0); 573 574 /* 575 * Application should provide a proper zone ID or the use of 576 * default zone IDs should be enabled. Unfortunately, some 577 * applications do not behave as it should, so we need a 578 * workaround. Even if an appropriate ID is not determined 579 * (when it's required), if we can determine the outgoing 580 * interface. determine the zone ID based on the interface. 581 */ 582 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL); 583 584 return (error); 585 } 586 587 /* 588 * Select source address based on @fibnum, @dst and @scopeid. 589 * Stores selected address to @srcp. 590 * Returns 0 on success. 591 * 592 * Used by non-socket based consumers (ND code mostly) 593 */ 594 int 595 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst, 596 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp, 597 int *hlim) 598 { 599 struct ifnet *retifp; 600 struct sockaddr_in6 dst_sa; 601 int error; 602 603 retifp = ifp; 604 bzero(&dst_sa, sizeof(dst_sa)); 605 dst_sa.sin6_family = AF_INET6; 606 dst_sa.sin6_len = sizeof(dst_sa); 607 dst_sa.sin6_addr = *dst; 608 dst_sa.sin6_scope_id = scopeid; 609 sa6_embedscope(&dst_sa, 0); 610 611 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL, NULL, &retifp, srcp); 612 if (hlim != NULL) 613 *hlim = in6_selecthlim(NULL, retifp); 614 615 return (error); 616 } 617 618 /* 619 * clone - meaningful only for bsdi and freebsd 620 */ 621 static int 622 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 623 struct ip6_moptions *mopts, struct route_in6 *ro, 624 struct ifnet **retifp, struct nhop_object **retnh, int norouteok, 625 u_int fibnum, uint32_t flowid) 626 { 627 int error = 0; 628 struct ifnet *ifp = NULL; 629 struct nhop_object *nh = NULL; 630 struct sockaddr_in6 *sin6_next; 631 struct in6_pktinfo *pi = NULL; 632 struct in6_addr *dst = &dstsock->sin6_addr; 633 uint32_t zoneid; 634 #if 0 635 char ip6buf[INET6_ADDRSTRLEN]; 636 637 if (dstsock->sin6_addr.s6_addr32[0] == 0 && 638 dstsock->sin6_addr.s6_addr32[1] == 0 && 639 !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) { 640 printf("%s: strange destination %s\n", __func__, 641 ip6_sprintf(ip6buf, &dstsock->sin6_addr)); 642 } else { 643 printf("%s: destination = %s%%%d\n", __func__, 644 ip6_sprintf(ip6buf, &dstsock->sin6_addr), 645 dstsock->sin6_scope_id); /* for debug */ 646 } 647 #endif 648 649 /* If the caller specify the outgoing interface explicitly, use it. */ 650 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 651 /* XXX boundary check is assumed to be already done. */ 652 ifp = ifnet_byindex(pi->ipi6_ifindex); 653 if (ifp != NULL && 654 (norouteok || retnh == NULL || 655 IN6_IS_ADDR_MULTICAST(dst))) { 656 /* 657 * we do not have to check or get the route for 658 * multicast. 659 */ 660 goto done; 661 } else 662 goto getroute; 663 } 664 /* 665 * If the destination address is a multicast address and the outgoing 666 * interface for the address is specified by the caller, use it. 667 */ 668 if (IN6_IS_ADDR_MULTICAST(dst) && 669 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 670 goto done; /* we do not need a route for multicast. */ 671 } 672 /* 673 * If destination address is LLA or link- or node-local multicast, 674 * use it's embedded scope zone id to determine outgoing interface. 675 */ 676 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) || 677 IN6_IS_ADDR_MC_NODELOCAL(dst)) { 678 zoneid = ntohs(in6_getscope(dst)); 679 if (zoneid > 0) { 680 ifp = in6_getlinkifnet(zoneid); 681 goto done; 682 } 683 } 684 685 getroute: 686 /* 687 * If the next hop address for the packet is specified by the caller, 688 * use it as the gateway. 689 */ 690 if (opts && opts->ip6po_nexthop) { 691 struct route_in6 *ron; 692 693 sin6_next = satosin6(opts->ip6po_nexthop); 694 if (IN6_IS_ADDR_LINKLOCAL(&sin6_next->sin6_addr)) { 695 /* 696 * Next hop is LLA, thus it should be neighbor. 697 * Determine outgoing interface by zone index. 698 */ 699 zoneid = ntohs(in6_getscope(&sin6_next->sin6_addr)); 700 if (zoneid > 0) { 701 ifp = in6_getlinkifnet(zoneid); 702 goto done; 703 } 704 } 705 ron = &opts->ip6po_nextroute; 706 /* Use a cached route if it exists and is valid. */ 707 if (ron->ro_nh != NULL && ( 708 !NH_IS_VALID(ron->ro_nh) || 709 ron->ro_dst.sin6_family != AF_INET6 || 710 !IN6_ARE_ADDR_EQUAL(&ron->ro_dst.sin6_addr, 711 &sin6_next->sin6_addr))) 712 RO_NHFREE(ron); 713 if (ron->ro_nh == NULL) { 714 ron->ro_dst = *sin6_next; 715 /* 716 * sin6_next is not link-local OR scopeid is 0, 717 * no need to clear scope 718 */ 719 ron->ro_nh = fib6_lookup(fibnum, 720 &sin6_next->sin6_addr, 0, NHR_REF, flowid); 721 } 722 /* 723 * The node identified by that address must be a 724 * neighbor of the sending host. 725 */ 726 if (ron->ro_nh == NULL || 727 (ron->ro_nh->nh_flags & NHF_GATEWAY) != 0) 728 error = EHOSTUNREACH; 729 else { 730 nh = ron->ro_nh; 731 ifp = nh->nh_ifp; 732 } 733 goto done; 734 } 735 736 /* 737 * Use a cached route if it exists and is valid, else try to allocate 738 * a new one. Note that we should check the address family of the 739 * cached destination, in case of sharing the cache with IPv4. 740 */ 741 if (ro) { 742 if (ro->ro_nh && 743 (!NH_IS_VALID(ro->ro_nh) || 744 ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 || 745 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, 746 dst))) { 747 RO_NHFREE(ro); 748 } 749 if (ro->ro_nh == (struct nhop_object *)NULL) { 750 struct sockaddr_in6 *sa6; 751 752 /* No route yet, so try to acquire one */ 753 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 754 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 755 *sa6 = *dstsock; 756 sa6->sin6_scope_id = 0; 757 758 /* 759 * Currently dst has scopeid embedded iff it is LL. 760 * New routing API accepts scopeid as a separate argument. 761 * Convert dst before/after doing lookup 762 */ 763 uint32_t scopeid = 0; 764 if (IN6_IS_SCOPE_LINKLOCAL(&sa6->sin6_addr)) { 765 /* Unwrap in6_getscope() and in6_clearscope() */ 766 scopeid = ntohs(sa6->sin6_addr.s6_addr16[1]); 767 sa6->sin6_addr.s6_addr16[1] = 0; 768 } 769 770 ro->ro_nh = fib6_lookup(fibnum, 771 &sa6->sin6_addr, scopeid, NHR_REF, flowid); 772 773 if (IN6_IS_SCOPE_LINKLOCAL(&sa6->sin6_addr)) 774 sa6->sin6_addr.s6_addr16[1] = htons(scopeid); 775 } 776 777 /* 778 * do not care about the result if we have the nexthop 779 * explicitly specified. 780 */ 781 if (opts && opts->ip6po_nexthop) 782 goto done; 783 784 if (ro->ro_nh) 785 ifp = ro->ro_nh->nh_ifp; 786 else 787 error = EHOSTUNREACH; 788 nh = ro->ro_nh; 789 790 /* 791 * Check if the outgoing interface conflicts with 792 * the interface specified by ipi6_ifindex (if specified). 793 * Note that loopback interface is always okay. 794 * (this may happen when we are sending a packet to one of 795 * our own addresses.) 796 */ 797 if (ifp && opts && opts->ip6po_pktinfo && 798 opts->ip6po_pktinfo->ipi6_ifindex) { 799 if (!(ifp->if_flags & IFF_LOOPBACK) && 800 ifp->if_index != 801 opts->ip6po_pktinfo->ipi6_ifindex) { 802 error = EHOSTUNREACH; 803 goto done; 804 } 805 } 806 } 807 808 done: 809 if (ifp == NULL && nh == NULL) { 810 /* 811 * This can happen if the caller did not pass a cached route 812 * nor any other hints. We treat this case an error. 813 */ 814 error = EHOSTUNREACH; 815 } 816 if (error == EHOSTUNREACH) 817 IP6STAT_INC(ip6s_noroute); 818 819 if (retifp != NULL) { 820 if (nh != NULL) 821 *retifp = nh->nh_aifp; 822 else 823 *retifp = ifp; 824 } 825 826 if (retnh != NULL) 827 *retnh = nh; /* nh may be NULL */ 828 829 return (error); 830 } 831 832 static int 833 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 834 struct ip6_moptions *mopts, struct ifnet **retifp, 835 struct ifnet *oifp, u_int fibnum) 836 { 837 int error; 838 struct route_in6 sro; 839 struct nhop_object *nh = NULL; 840 uint16_t nh_flags; 841 842 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__)); 843 844 bzero(&sro, sizeof(sro)); 845 nh_flags = 0; 846 847 error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0); 848 849 if (nh != NULL) 850 nh_flags = nh->nh_flags; 851 if (nh != NULL && nh == sro.ro_nh) 852 NH_FREE(nh); 853 854 if (error != 0) { 855 /* Help ND. See oifp comment in in6_selectsrc(). */ 856 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) { 857 *retifp = oifp; 858 error = 0; 859 } 860 return (error); 861 } 862 863 /* 864 * do not use a rejected or black hole route. 865 * XXX: this check should be done in the L2 output routine. 866 * However, if we skipped this check here, we'd see the following 867 * scenario: 868 * - install a rejected route for a scoped address prefix 869 * (like fe80::/10) 870 * - send a packet to a destination that matches the scoped prefix, 871 * with ambiguity about the scope zone. 872 * - pick the outgoing interface from the route, and disambiguate the 873 * scope zone with the interface. 874 * - ip6_output() would try to get another route with the "new" 875 * destination, which may be valid. 876 * - we'd see no error on output. 877 * Although this may not be very harmful, it should still be confusing. 878 * We thus reject the case here. 879 */ 880 881 if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) { 882 error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH); 883 return (error); 884 } 885 886 return (0); 887 } 888 889 /* Public wrapper function to selectroute(). */ 890 int 891 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 892 struct ip6_moptions *mopts, struct route_in6 *ro, 893 struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid) 894 { 895 896 return (selectroute(dstsock, opts, mopts, ro, retifp, 897 retnh, 0, fibnum, flowid)); 898 } 899 900 /* 901 * Default hop limit selection. The precedence is as follows: 902 * 1. Hoplimit value specified via ioctl. 903 * 2. (If the outgoing interface is detected) the current 904 * hop limit of the interface specified by router advertisement. 905 * 3. The system default hoplimit. 906 */ 907 int 908 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp) 909 { 910 911 if (inp && inp->in6p_hops >= 0) 912 return (inp->in6p_hops); 913 else if (ifp) 914 return (ND_IFINFO(ifp)->chlim); 915 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 916 struct nhop_object *nh; 917 struct in6_addr dst; 918 uint32_t fibnum, scopeid; 919 int hlim; 920 921 fibnum = inp->inp_inc.inc_fibnum; 922 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid); 923 nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0); 924 if (nh != NULL) { 925 hlim = ND_IFINFO(nh->nh_ifp)->chlim; 926 return (hlim); 927 } 928 } 929 return (V_ip6_defhlim); 930 } 931 932 /* 933 * XXX: this is borrowed from in6_pcbbind(). If possible, we should 934 * share this function by all *bsd*... 935 */ 936 int 937 in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct ucred *cred) 938 { 939 struct socket *so = inp->inp_socket; 940 u_int16_t lport = 0; 941 int error, lookupflags = 0; 942 #ifdef INVARIANTS 943 struct inpcbinfo *pcbinfo = inp->inp_pcbinfo; 944 #endif 945 946 INP_WLOCK_ASSERT(inp); 947 INP_HASH_WLOCK_ASSERT(pcbinfo); 948 949 error = prison_local_ip6(cred, laddr, 950 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)); 951 if (error) 952 return(error); 953 954 /* XXX: this is redundant when called from in6_pcbbind */ 955 if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT|SO_REUSEPORT_LB)) == 0) 956 lookupflags = INPLOOKUP_WILDCARD; 957 958 inp->inp_flags |= INP_ANONPORT; 959 960 error = in_pcb_lport(inp, NULL, &lport, cred, lookupflags); 961 if (error != 0) 962 return (error); 963 964 inp->inp_lport = lport; 965 if (in_pcbinshash(inp) != 0) { 966 inp->in6p_laddr = in6addr_any; 967 inp->inp_lport = 0; 968 return (EAGAIN); 969 } 970 971 return (0); 972 } 973 974 void 975 addrsel_policy_init(void) 976 { 977 978 init_policy_queue(); 979 980 /* initialize the "last resort" policy */ 981 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy)); 982 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP; 983 984 if (!IS_DEFAULT_VNET(curvnet)) 985 return; 986 987 ADDRSEL_LOCK_INIT(); 988 ADDRSEL_SXLOCK_INIT(); 989 } 990 991 static struct in6_addrpolicy * 992 lookup_addrsel_policy(struct sockaddr_in6 *key) 993 { 994 struct in6_addrpolicy *match = NULL; 995 996 ADDRSEL_LOCK(); 997 match = match_addrsel_policy(key); 998 999 if (match == NULL) 1000 match = &V_defaultaddrpolicy; 1001 else 1002 match->use++; 1003 ADDRSEL_UNLOCK(); 1004 1005 return (match); 1006 } 1007 1008 /* 1009 * Subroutines to manage the address selection policy table via sysctl. 1010 */ 1011 struct walkarg { 1012 struct sysctl_req *w_req; 1013 }; 1014 1015 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS); 1016 SYSCTL_DECL(_net_inet6_ip6); 1017 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy, 1018 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl, 1019 ""); 1020 1021 static int 1022 in6_src_sysctl(SYSCTL_HANDLER_ARGS) 1023 { 1024 struct walkarg w; 1025 1026 if (req->newptr) 1027 return EPERM; 1028 1029 bzero(&w, sizeof(w)); 1030 w.w_req = req; 1031 1032 return (walk_addrsel_policy(dump_addrsel_policyent, &w)); 1033 } 1034 1035 int 1036 in6_src_ioctl(u_long cmd, caddr_t data) 1037 { 1038 struct in6_addrpolicy ent0; 1039 1040 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY) 1041 return (EOPNOTSUPP); /* check for safety */ 1042 1043 ent0 = *(struct in6_addrpolicy *)data; 1044 1045 if (ent0.label == ADDR_LABEL_NOTAPP) 1046 return (EINVAL); 1047 /* check if the prefix mask is consecutive. */ 1048 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0) 1049 return (EINVAL); 1050 /* clear trailing garbages (if any) of the prefix address. */ 1051 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr); 1052 ent0.use = 0; 1053 1054 switch (cmd) { 1055 case SIOCAADDRCTL_POLICY: 1056 return (add_addrsel_policyent(&ent0)); 1057 case SIOCDADDRCTL_POLICY: 1058 return (delete_addrsel_policyent(&ent0)); 1059 } 1060 1061 return (0); /* XXX: compromise compilers */ 1062 } 1063 1064 /* 1065 * The followings are implementation of the policy table using a 1066 * simple tail queue. 1067 * XXX such details should be hidden. 1068 * XXX implementation using binary tree should be more efficient. 1069 */ 1070 struct addrsel_policyent { 1071 TAILQ_ENTRY(addrsel_policyent) ape_entry; 1072 struct in6_addrpolicy ape_policy; 1073 }; 1074 1075 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent); 1076 1077 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab); 1078 #define V_addrsel_policytab VNET(addrsel_policytab) 1079 1080 static void 1081 init_policy_queue(void) 1082 { 1083 1084 TAILQ_INIT(&V_addrsel_policytab); 1085 } 1086 1087 static int 1088 add_addrsel_policyent(struct in6_addrpolicy *newpolicy) 1089 { 1090 struct addrsel_policyent *new, *pol; 1091 1092 new = malloc(sizeof(*new), M_IFADDR, 1093 M_WAITOK); 1094 ADDRSEL_XLOCK(); 1095 ADDRSEL_LOCK(); 1096 1097 /* duplication check */ 1098 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1099 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr, 1100 &pol->ape_policy.addr.sin6_addr) && 1101 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr, 1102 &pol->ape_policy.addrmask.sin6_addr)) { 1103 ADDRSEL_UNLOCK(); 1104 ADDRSEL_XUNLOCK(); 1105 free(new, M_IFADDR); 1106 return (EEXIST); /* or override it? */ 1107 } 1108 } 1109 1110 bzero(new, sizeof(*new)); 1111 1112 /* XXX: should validate entry */ 1113 new->ape_policy = *newpolicy; 1114 1115 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry); 1116 ADDRSEL_UNLOCK(); 1117 ADDRSEL_XUNLOCK(); 1118 1119 return (0); 1120 } 1121 1122 static int 1123 delete_addrsel_policyent(struct in6_addrpolicy *key) 1124 { 1125 struct addrsel_policyent *pol; 1126 1127 ADDRSEL_XLOCK(); 1128 ADDRSEL_LOCK(); 1129 1130 /* search for the entry in the table */ 1131 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1132 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr, 1133 &pol->ape_policy.addr.sin6_addr) && 1134 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr, 1135 &pol->ape_policy.addrmask.sin6_addr)) { 1136 break; 1137 } 1138 } 1139 if (pol == NULL) { 1140 ADDRSEL_UNLOCK(); 1141 ADDRSEL_XUNLOCK(); 1142 return (ESRCH); 1143 } 1144 1145 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry); 1146 ADDRSEL_UNLOCK(); 1147 ADDRSEL_XUNLOCK(); 1148 free(pol, M_IFADDR); 1149 1150 return (0); 1151 } 1152 1153 static int 1154 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w) 1155 { 1156 struct addrsel_policyent *pol; 1157 int error = 0; 1158 1159 ADDRSEL_SLOCK(); 1160 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1161 if ((error = (*callback)(&pol->ape_policy, w)) != 0) { 1162 ADDRSEL_SUNLOCK(); 1163 return (error); 1164 } 1165 } 1166 ADDRSEL_SUNLOCK(); 1167 return (error); 1168 } 1169 1170 static int 1171 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg) 1172 { 1173 int error = 0; 1174 struct walkarg *w = arg; 1175 1176 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol)); 1177 1178 return (error); 1179 } 1180 1181 static struct in6_addrpolicy * 1182 match_addrsel_policy(struct sockaddr_in6 *key) 1183 { 1184 struct addrsel_policyent *pent; 1185 struct in6_addrpolicy *bestpol = NULL, *pol; 1186 int matchlen, bestmatchlen = -1; 1187 u_char *mp, *ep, *k, *p, m; 1188 1189 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) { 1190 matchlen = 0; 1191 1192 pol = &pent->ape_policy; 1193 mp = (u_char *)&pol->addrmask.sin6_addr; 1194 ep = mp + 16; /* XXX: scope field? */ 1195 k = (u_char *)&key->sin6_addr; 1196 p = (u_char *)&pol->addr.sin6_addr; 1197 for (; mp < ep && *mp; mp++, k++, p++) { 1198 m = *mp; 1199 if ((*k & m) != *p) 1200 goto next; /* not match */ 1201 if (m == 0xff) /* short cut for a typical case */ 1202 matchlen += 8; 1203 else { 1204 while (m >= 0x80) { 1205 matchlen++; 1206 m <<= 1; 1207 } 1208 } 1209 } 1210 1211 /* matched. check if this is better than the current best. */ 1212 if (bestpol == NULL || 1213 matchlen > bestmatchlen) { 1214 bestpol = pol; 1215 bestmatchlen = matchlen; 1216 } 1217 1218 next: 1219 continue; 1220 } 1221 1222 return (bestpol); 1223 } 1224