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 "opt_mpath.h" 71 72 #include <sys/param.h> 73 #include <sys/systm.h> 74 #include <sys/lock.h> 75 #include <sys/malloc.h> 76 #include <sys/mbuf.h> 77 #include <sys/priv.h> 78 #include <sys/protosw.h> 79 #include <sys/socket.h> 80 #include <sys/socketvar.h> 81 #include <sys/sockio.h> 82 #include <sys/sysctl.h> 83 #include <sys/errno.h> 84 #include <sys/time.h> 85 #include <sys/jail.h> 86 #include <sys/kernel.h> 87 #include <sys/rmlock.h> 88 #include <sys/sx.h> 89 90 #include <net/if.h> 91 #include <net/if_var.h> 92 #include <net/if_dl.h> 93 #include <net/route.h> 94 #include <net/if_llatbl.h> 95 #ifdef RADIX_MPATH 96 #include <net/radix_mpath.h> 97 #endif 98 99 #include <netinet/in.h> 100 #include <netinet/in_var.h> 101 #include <netinet/in_systm.h> 102 #include <netinet/ip.h> 103 #include <netinet/in_pcb.h> 104 #include <netinet/ip_var.h> 105 #include <netinet/udp.h> 106 #include <netinet/udp_var.h> 107 108 #include <netinet6/in6_var.h> 109 #include <netinet/ip6.h> 110 #include <netinet6/in6_fib.h> 111 #include <netinet6/in6_pcb.h> 112 #include <netinet6/ip6_var.h> 113 #include <netinet6/scope6_var.h> 114 #include <netinet6/nd6.h> 115 116 static struct mtx addrsel_lock; 117 #define ADDRSEL_LOCK_INIT() mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF) 118 #define ADDRSEL_LOCK() mtx_lock(&addrsel_lock) 119 #define ADDRSEL_UNLOCK() mtx_unlock(&addrsel_lock) 120 #define ADDRSEL_LOCK_ASSERT() mtx_assert(&addrsel_lock, MA_OWNED) 121 122 static struct sx addrsel_sxlock; 123 #define ADDRSEL_SXLOCK_INIT() sx_init(&addrsel_sxlock, "addrsel_sxlock") 124 #define ADDRSEL_SLOCK() sx_slock(&addrsel_sxlock) 125 #define ADDRSEL_SUNLOCK() sx_sunlock(&addrsel_sxlock) 126 #define ADDRSEL_XLOCK() sx_xlock(&addrsel_sxlock) 127 #define ADDRSEL_XUNLOCK() sx_xunlock(&addrsel_sxlock) 128 129 #define ADDR_LABEL_NOTAPP (-1) 130 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy); 131 #define V_defaultaddrpolicy VNET(defaultaddrpolicy) 132 133 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0; 134 135 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *, 136 struct ip6_moptions *, struct route_in6 *, struct ifnet **, 137 struct rtentry **, int, u_int); 138 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *, 139 struct ip6_moptions *, struct ifnet **, 140 struct ifnet *, u_int); 141 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *, 142 struct ip6_pktopts *, struct inpcb *, struct ucred *, 143 struct ifnet **, struct in6_addr *); 144 145 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *); 146 147 static void init_policy_queue(void); 148 static int add_addrsel_policyent(struct in6_addrpolicy *); 149 static int delete_addrsel_policyent(struct in6_addrpolicy *); 150 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *), 151 void *); 152 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *); 153 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *); 154 155 /* 156 * Return an IPv6 address, which is the most appropriate for a given 157 * destination and user specified options. 158 * If necessary, this function lookups the routing table and returns 159 * an entry to the caller for later use. 160 */ 161 #define REPLACE(r) do {\ 162 IP6STAT_INC(ip6s_sources_rule[(r)]); \ 163 /* { \ 164 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 165 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)); \ 166 } */ \ 167 goto replace; \ 168 } while(0) 169 #define NEXT(r) do {\ 170 /* { \ 171 char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \ 172 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)); \ 173 } */ \ 174 goto next; /* XXX: we can't use 'continue' here */ \ 175 } while(0) 176 #define BREAK(r) do { \ 177 IP6STAT_INC(ip6s_sources_rule[(r)]); \ 178 goto out; /* XXX: we can't use 'break' here */ \ 179 } while(0) 180 181 static int 182 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock, 183 struct ip6_pktopts *opts, struct inpcb *inp, struct ucred *cred, 184 struct ifnet **ifpp, struct in6_addr *srcp) 185 { 186 struct rm_priotracker in6_ifa_tracker; 187 struct in6_addr dst, tmp; 188 struct ifnet *ifp = NULL, *oifp = NULL; 189 struct in6_ifaddr *ia = NULL, *ia_best = NULL; 190 struct in6_pktinfo *pi = NULL; 191 int dst_scope = -1, best_scope = -1, best_matchlen = -1; 192 struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL; 193 u_int32_t odstzone; 194 int prefer_tempaddr; 195 int error; 196 struct ip6_moptions *mopts; 197 198 KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__)); 199 200 dst = dstsock->sin6_addr; /* make a copy for local operation */ 201 if (ifpp) { 202 /* 203 * Save a possibly passed in ifp for in6_selectsrc. Only 204 * neighbor discovery code should use this feature, where 205 * we may know the interface but not the FIB number holding 206 * the connected subnet in case someone deleted it from the 207 * default FIB and we need to check the interface. 208 */ 209 if (*ifpp != NULL) 210 oifp = *ifpp; 211 *ifpp = NULL; 212 } 213 214 if (inp != NULL) { 215 INP_LOCK_ASSERT(inp); 216 mopts = inp->in6p_moptions; 217 } else { 218 mopts = NULL; 219 } 220 221 /* 222 * If the source address is explicitly specified by the caller, 223 * check if the requested source address is indeed a unicast address 224 * assigned to the node, and can be used as the packet's source 225 * address. If everything is okay, use the address as source. 226 */ 227 if (opts && (pi = opts->ip6po_pktinfo) && 228 !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) { 229 /* get the outgoing interface */ 230 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 231 fibnum)) 232 != 0) 233 return (error); 234 235 /* 236 * determine the appropriate zone id of the source based on 237 * the zone of the destination and the outgoing interface. 238 * If the specified address is ambiguous wrt the scope zone, 239 * the interface must be specified; otherwise, ifa_ifwithaddr() 240 * will fail matching the address. 241 */ 242 tmp = pi->ipi6_addr; 243 if (ifp) { 244 error = in6_setscope(&tmp, ifp, &odstzone); 245 if (error) 246 return (error); 247 } 248 if (cred != NULL && (error = prison_local_ip6(cred, 249 &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) 250 return (error); 251 252 /* 253 * If IPV6_BINDANY socket option is set, we allow to specify 254 * non local addresses as source address in IPV6_PKTINFO 255 * ancillary data. 256 */ 257 if ((inp->inp_flags & INP_BINDANY) == 0) { 258 ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */); 259 if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST | 260 IN6_IFF_NOTREADY))) { 261 if (ia != NULL) 262 ifa_free(&ia->ia_ifa); 263 return (EADDRNOTAVAIL); 264 } 265 bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp)); 266 ifa_free(&ia->ia_ifa); 267 } else 268 bcopy(&tmp, srcp, sizeof(*srcp)); 269 pi->ipi6_addr = tmp; /* XXX: this overrides pi */ 270 if (ifpp) 271 *ifpp = ifp; 272 return (0); 273 } 274 275 /* 276 * Otherwise, if the socket has already bound the source, just use it. 277 */ 278 if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) { 279 if (cred != NULL && 280 (error = prison_local_ip6(cred, &inp->in6p_laddr, 281 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0) 282 return (error); 283 bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp)); 284 return (0); 285 } 286 287 /* 288 * Bypass source address selection and use the primary jail IP 289 * if requested. 290 */ 291 if (cred != NULL && !prison_saddrsel_ip6(cred, srcp)) 292 return (0); 293 294 /* 295 * If the address is not specified, choose the best one based on 296 * the outgoing interface and the destination address. 297 */ 298 /* get the outgoing interface */ 299 if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp, 300 (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0) 301 return (error); 302 303 #ifdef DIAGNOSTIC 304 if (ifp == NULL) /* this should not happen */ 305 panic("in6_selectsrc: NULL ifp"); 306 #endif 307 error = in6_setscope(&dst, ifp, &odstzone); 308 if (error) 309 return (error); 310 311 IN6_IFADDR_RLOCK(&in6_ifa_tracker); 312 CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) { 313 int new_scope = -1, new_matchlen = -1; 314 struct in6_addrpolicy *new_policy = NULL; 315 u_int32_t srczone, osrczone, dstzone; 316 struct in6_addr src; 317 struct ifnet *ifp1 = ia->ia_ifp; 318 319 /* 320 * We'll never take an address that breaks the scope zone 321 * of the destination. We also skip an address if its zone 322 * does not contain the outgoing interface. 323 * XXX: we should probably use sin6_scope_id here. 324 */ 325 if (in6_setscope(&dst, ifp1, &dstzone) || 326 odstzone != dstzone) { 327 continue; 328 } 329 src = ia->ia_addr.sin6_addr; 330 if (in6_setscope(&src, ifp, &osrczone) || 331 in6_setscope(&src, ifp1, &srczone) || 332 osrczone != srczone) { 333 continue; 334 } 335 336 /* avoid unusable addresses */ 337 if ((ia->ia6_flags & 338 (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) { 339 continue; 340 } 341 if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia)) 342 continue; 343 344 /* If jailed only take addresses of the jail into account. */ 345 if (cred != NULL && 346 prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0) 347 continue; 348 349 /* Rule 1: Prefer same address */ 350 if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) { 351 ia_best = ia; 352 BREAK(1); /* there should be no better candidate */ 353 } 354 355 if (ia_best == NULL) 356 REPLACE(0); 357 358 /* Rule 2: Prefer appropriate scope */ 359 if (dst_scope < 0) 360 dst_scope = in6_addrscope(&dst); 361 new_scope = in6_addrscope(&ia->ia_addr.sin6_addr); 362 if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) { 363 if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0) 364 REPLACE(2); 365 NEXT(2); 366 } else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) { 367 if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0) 368 NEXT(2); 369 REPLACE(2); 370 } 371 372 /* 373 * Rule 3: Avoid deprecated addresses. Note that the case of 374 * !ip6_use_deprecated is already rejected above. 375 */ 376 if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia)) 377 NEXT(3); 378 if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia)) 379 REPLACE(3); 380 381 /* Rule 4: Prefer home addresses */ 382 /* 383 * XXX: This is a TODO. We should probably merge the MIP6 384 * case above. 385 */ 386 387 /* Rule 5: Prefer outgoing interface */ 388 if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) { 389 if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp) 390 NEXT(5); 391 if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp) 392 REPLACE(5); 393 } 394 395 /* 396 * Rule 6: Prefer matching label 397 * Note that best_policy should be non-NULL here. 398 */ 399 if (dst_policy == NULL) 400 dst_policy = lookup_addrsel_policy(dstsock); 401 if (dst_policy->label != ADDR_LABEL_NOTAPP) { 402 new_policy = lookup_addrsel_policy(&ia->ia_addr); 403 if (dst_policy->label == best_policy->label && 404 dst_policy->label != new_policy->label) 405 NEXT(6); 406 if (dst_policy->label != best_policy->label && 407 dst_policy->label == new_policy->label) 408 REPLACE(6); 409 } 410 411 /* 412 * Rule 7: Prefer public addresses. 413 * We allow users to reverse the logic by configuring 414 * a sysctl variable, so that privacy conscious users can 415 * always prefer temporary addresses. 416 */ 417 if (opts == NULL || 418 opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) { 419 prefer_tempaddr = V_ip6_prefer_tempaddr; 420 } else if (opts->ip6po_prefer_tempaddr == 421 IP6PO_TEMPADDR_NOTPREFER) { 422 prefer_tempaddr = 0; 423 } else 424 prefer_tempaddr = 1; 425 if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 426 (ia->ia6_flags & IN6_IFF_TEMPORARY)) { 427 if (prefer_tempaddr) 428 REPLACE(7); 429 else 430 NEXT(7); 431 } 432 if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) && 433 !(ia->ia6_flags & IN6_IFF_TEMPORARY)) { 434 if (prefer_tempaddr) 435 NEXT(7); 436 else 437 REPLACE(7); 438 } 439 440 /* 441 * Rule 8: prefer addresses on alive interfaces. 442 * This is a KAME specific rule. 443 */ 444 if ((ia_best->ia_ifp->if_flags & IFF_UP) && 445 !(ia->ia_ifp->if_flags & IFF_UP)) 446 NEXT(8); 447 if (!(ia_best->ia_ifp->if_flags & IFF_UP) && 448 (ia->ia_ifp->if_flags & IFF_UP)) 449 REPLACE(8); 450 451 /* 452 * Rule 9: prefer address with better virtual status. 453 */ 454 if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa)) 455 REPLACE(9); 456 if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa)) 457 NEXT(9); 458 459 /* 460 * Rule 10: prefer address with `prefer_source' flag. 461 */ 462 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 && 463 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0) 464 REPLACE(10); 465 if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 && 466 (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0) 467 NEXT(10); 468 469 /* 470 * Rule 14: Use longest matching prefix. 471 * Note: in the address selection draft, this rule is 472 * documented as "Rule 8". However, since it is also 473 * documented that this rule can be overridden, we assign 474 * a large number so that it is easy to assign smaller numbers 475 * to more preferred rules. 476 */ 477 new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst); 478 if (best_matchlen < new_matchlen) 479 REPLACE(14); 480 if (new_matchlen < best_matchlen) 481 NEXT(14); 482 483 /* Rule 15 is reserved. */ 484 485 /* 486 * Last resort: just keep the current candidate. 487 * Or, do we need more rules? 488 */ 489 continue; 490 491 replace: 492 ia_best = ia; 493 best_scope = (new_scope >= 0 ? new_scope : 494 in6_addrscope(&ia_best->ia_addr.sin6_addr)); 495 best_policy = (new_policy ? new_policy : 496 lookup_addrsel_policy(&ia_best->ia_addr)); 497 best_matchlen = (new_matchlen >= 0 ? new_matchlen : 498 in6_matchlen(&ia_best->ia_addr.sin6_addr, 499 &dst)); 500 501 next: 502 continue; 503 504 out: 505 break; 506 } 507 508 if ((ia = ia_best) == NULL) { 509 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 510 IP6STAT_INC(ip6s_sources_none); 511 return (EADDRNOTAVAIL); 512 } 513 514 /* 515 * At this point at least one of the addresses belonged to the jail 516 * but it could still be, that we want to further restrict it, e.g. 517 * theoratically IN6_IS_ADDR_LOOPBACK. 518 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore. 519 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should 520 * let all others previously selected pass. 521 * Use tmp to not change ::1 on lo0 to the primary jail address. 522 */ 523 tmp = ia->ia_addr.sin6_addr; 524 if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL && 525 (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) { 526 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 527 IP6STAT_INC(ip6s_sources_none); 528 return (EADDRNOTAVAIL); 529 } 530 531 if (ifpp) 532 *ifpp = ifp; 533 534 bcopy(&tmp, srcp, sizeof(*srcp)); 535 if (ia->ia_ifp == ifp) 536 IP6STAT_INC(ip6s_sources_sameif[best_scope]); 537 else 538 IP6STAT_INC(ip6s_sources_otherif[best_scope]); 539 if (dst_scope == best_scope) 540 IP6STAT_INC(ip6s_sources_samescope[best_scope]); 541 else 542 IP6STAT_INC(ip6s_sources_otherscope[best_scope]); 543 if (IFA6_IS_DEPRECATED(ia)) 544 IP6STAT_INC(ip6s_sources_deprecated[best_scope]); 545 IN6_IFADDR_RUNLOCK(&in6_ifa_tracker); 546 return (0); 547 } 548 549 /* 550 * Select source address based on @inp, @dstsock and @opts. 551 * Stores selected address to @srcp. If @scope_ambiguous is set, 552 * embed scope from selected outgoing interface. If @hlim pointer 553 * is provided, stores calculated hop limit there. 554 * Returns 0 on success. 555 */ 556 int 557 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 558 struct inpcb *inp, struct ucred *cred, int scope_ambiguous, 559 struct in6_addr *srcp, int *hlim) 560 { 561 struct ifnet *retifp; 562 uint32_t fibnum; 563 int error; 564 565 fibnum = inp->inp_inc.inc_fibnum; 566 retifp = NULL; 567 568 error = in6_selectsrc(fibnum, dstsock, opts, inp, cred, &retifp, srcp); 569 if (error != 0) 570 return (error); 571 572 if (hlim != NULL) 573 *hlim = in6_selecthlim(inp, retifp); 574 575 if (retifp == NULL || scope_ambiguous == 0) 576 return (0); 577 578 /* 579 * Application should provide a proper zone ID or the use of 580 * default zone IDs should be enabled. Unfortunately, some 581 * applications do not behave as it should, so we need a 582 * workaround. Even if an appropriate ID is not determined 583 * (when it's required), if we can determine the outgoing 584 * interface. determine the zone ID based on the interface. 585 */ 586 error = in6_setscope(&dstsock->sin6_addr, retifp, NULL); 587 588 return (error); 589 } 590 591 /* 592 * Select source address based on @fibnum, @dst and @scopeid. 593 * Stores selected address to @srcp. 594 * Returns 0 on success. 595 * 596 * Used by non-socket based consumers (ND code mostly) 597 */ 598 int 599 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst, 600 uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp, 601 int *hlim) 602 { 603 struct ifnet *retifp; 604 struct sockaddr_in6 dst_sa; 605 int error; 606 607 retifp = ifp; 608 bzero(&dst_sa, sizeof(dst_sa)); 609 dst_sa.sin6_family = AF_INET6; 610 dst_sa.sin6_len = sizeof(dst_sa); 611 dst_sa.sin6_addr = *dst; 612 dst_sa.sin6_scope_id = scopeid; 613 sa6_embedscope(&dst_sa, 0); 614 615 error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL, NULL, &retifp, srcp); 616 if (hlim != NULL) 617 *hlim = in6_selecthlim(NULL, retifp); 618 619 return (error); 620 } 621 622 /* 623 * clone - meaningful only for bsdi and freebsd 624 */ 625 static int 626 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 627 struct ip6_moptions *mopts, struct route_in6 *ro, 628 struct ifnet **retifp, struct rtentry **retrt, int norouteok, u_int fibnum) 629 { 630 int error = 0; 631 struct ifnet *ifp = NULL; 632 struct rtentry *rt = NULL; 633 struct sockaddr_in6 *sin6_next; 634 struct in6_pktinfo *pi = NULL; 635 struct in6_addr *dst = &dstsock->sin6_addr; 636 uint32_t zoneid; 637 #if 0 638 char ip6buf[INET6_ADDRSTRLEN]; 639 640 if (dstsock->sin6_addr.s6_addr32[0] == 0 && 641 dstsock->sin6_addr.s6_addr32[1] == 0 && 642 !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) { 643 printf("%s: strange destination %s\n", __func__, 644 ip6_sprintf(ip6buf, &dstsock->sin6_addr)); 645 } else { 646 printf("%s: destination = %s%%%d\n", __func__, 647 ip6_sprintf(ip6buf, &dstsock->sin6_addr), 648 dstsock->sin6_scope_id); /* for debug */ 649 } 650 #endif 651 652 /* If the caller specify the outgoing interface explicitly, use it. */ 653 if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) { 654 /* XXX boundary check is assumed to be already done. */ 655 ifp = ifnet_byindex(pi->ipi6_ifindex); 656 if (ifp != NULL && 657 (norouteok || retrt == NULL || 658 IN6_IS_ADDR_MULTICAST(dst))) { 659 /* 660 * we do not have to check or get the route for 661 * multicast. 662 */ 663 goto done; 664 } else 665 goto getroute; 666 } 667 /* 668 * If the destination address is a multicast address and the outgoing 669 * interface for the address is specified by the caller, use it. 670 */ 671 if (IN6_IS_ADDR_MULTICAST(dst) && 672 mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) { 673 goto done; /* we do not need a route for multicast. */ 674 } 675 /* 676 * If destination address is LLA or link- or node-local multicast, 677 * use it's embedded scope zone id to determine outgoing interface. 678 */ 679 if (IN6_IS_ADDR_MC_LINKLOCAL(dst) || 680 IN6_IS_ADDR_MC_NODELOCAL(dst)) { 681 zoneid = ntohs(in6_getscope(dst)); 682 if (zoneid > 0) { 683 ifp = in6_getlinkifnet(zoneid); 684 goto done; 685 } 686 } 687 688 getroute: 689 /* 690 * If the next hop address for the packet is specified by the caller, 691 * use it as the gateway. 692 */ 693 if (opts && opts->ip6po_nexthop) { 694 struct route_in6 *ron; 695 696 sin6_next = satosin6(opts->ip6po_nexthop); 697 if (IN6_IS_ADDR_LINKLOCAL(&sin6_next->sin6_addr)) { 698 /* 699 * Next hop is LLA, thus it should be neighbor. 700 * Determine outgoing interface by zone index. 701 */ 702 zoneid = ntohs(in6_getscope(&sin6_next->sin6_addr)); 703 if (zoneid > 0) { 704 ifp = in6_getlinkifnet(zoneid); 705 goto done; 706 } 707 } 708 ron = &opts->ip6po_nextroute; 709 /* Use a cached route if it exists and is valid. */ 710 if (ron->ro_rt != NULL && ( 711 (ron->ro_rt->rt_flags & RTF_UP) == 0 || 712 ron->ro_dst.sin6_family != AF_INET6 || 713 !IN6_ARE_ADDR_EQUAL(&ron->ro_dst.sin6_addr, 714 &sin6_next->sin6_addr))) 715 RO_RTFREE(ron); 716 if (ron->ro_rt == NULL) { 717 ron->ro_dst = *sin6_next; 718 in6_rtalloc(ron, fibnum); /* multi path case? */ 719 } 720 /* 721 * The node identified by that address must be a 722 * neighbor of the sending host. 723 */ 724 if (ron->ro_rt == NULL || 725 (ron->ro_rt->rt_flags & RTF_GATEWAY) != 0) 726 error = EHOSTUNREACH; 727 else { 728 rt = ron->ro_rt; 729 ifp = rt->rt_ifp; 730 } 731 goto done; 732 } 733 734 /* 735 * Use a cached route if it exists and is valid, else try to allocate 736 * a new one. Note that we should check the address family of the 737 * cached destination, in case of sharing the cache with IPv4. 738 */ 739 if (ro) { 740 if (ro->ro_rt && 741 (!(ro->ro_rt->rt_flags & RTF_UP) || 742 ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 || 743 !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr, 744 dst))) { 745 RTFREE(ro->ro_rt); 746 ro->ro_rt = (struct rtentry *)NULL; 747 } 748 if (ro->ro_rt == (struct rtentry *)NULL) { 749 struct sockaddr_in6 *sa6; 750 751 /* No route yet, so try to acquire one */ 752 bzero(&ro->ro_dst, sizeof(struct sockaddr_in6)); 753 sa6 = (struct sockaddr_in6 *)&ro->ro_dst; 754 *sa6 = *dstsock; 755 sa6->sin6_scope_id = 0; 756 757 #ifdef RADIX_MPATH 758 rtalloc_mpath_fib((struct route *)ro, 759 ntohl(sa6->sin6_addr.s6_addr32[3]), fibnum); 760 #else 761 ro->ro_rt = in6_rtalloc1((struct sockaddr *) 762 &ro->ro_dst, 0, 0UL, fibnum); 763 if (ro->ro_rt) 764 RT_UNLOCK(ro->ro_rt); 765 #endif 766 } 767 768 /* 769 * do not care about the result if we have the nexthop 770 * explicitly specified. 771 */ 772 if (opts && opts->ip6po_nexthop) 773 goto done; 774 775 if (ro->ro_rt) { 776 ifp = ro->ro_rt->rt_ifp; 777 778 if (ifp == NULL) { /* can this really happen? */ 779 RTFREE(ro->ro_rt); 780 ro->ro_rt = NULL; 781 } 782 } 783 if (ro->ro_rt == NULL) 784 error = EHOSTUNREACH; 785 rt = ro->ro_rt; 786 787 /* 788 * Check if the outgoing interface conflicts with 789 * the interface specified by ipi6_ifindex (if specified). 790 * Note that loopback interface is always okay. 791 * (this may happen when we are sending a packet to one of 792 * our own addresses.) 793 */ 794 if (ifp && opts && opts->ip6po_pktinfo && 795 opts->ip6po_pktinfo->ipi6_ifindex) { 796 if (!(ifp->if_flags & IFF_LOOPBACK) && 797 ifp->if_index != 798 opts->ip6po_pktinfo->ipi6_ifindex) { 799 error = EHOSTUNREACH; 800 goto done; 801 } 802 } 803 } 804 805 done: 806 if (ifp == NULL && rt == NULL) { 807 /* 808 * This can happen if the caller did not pass a cached route 809 * nor any other hints. We treat this case an error. 810 */ 811 error = EHOSTUNREACH; 812 } 813 if (error == EHOSTUNREACH) 814 IP6STAT_INC(ip6s_noroute); 815 816 if (retifp != NULL) { 817 *retifp = ifp; 818 819 /* 820 * Adjust the "outgoing" interface. If we're going to loop 821 * the packet back to ourselves, the ifp would be the loopback 822 * interface. However, we'd rather know the interface associated 823 * to the destination address (which should probably be one of 824 * our own addresses.) 825 */ 826 if (rt) { 827 if ((rt->rt_ifp->if_flags & IFF_LOOPBACK) && 828 (rt->rt_gateway->sa_family == AF_LINK)) 829 *retifp = 830 ifnet_byindex(((struct sockaddr_dl *) 831 rt->rt_gateway)->sdl_index); 832 } 833 } 834 835 if (retrt != NULL) 836 *retrt = rt; /* rt may be NULL */ 837 838 return (error); 839 } 840 841 static int 842 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 843 struct ip6_moptions *mopts, struct ifnet **retifp, 844 struct ifnet *oifp, u_int fibnum) 845 { 846 int error; 847 struct route_in6 sro; 848 struct rtentry *rt = NULL; 849 int rt_flags; 850 851 KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__)); 852 853 bzero(&sro, sizeof(sro)); 854 rt_flags = 0; 855 856 error = selectroute(dstsock, opts, mopts, &sro, retifp, &rt, 1, fibnum); 857 858 if (rt) 859 rt_flags = rt->rt_flags; 860 if (rt && rt == sro.ro_rt) 861 RTFREE(rt); 862 863 if (error != 0) { 864 /* Help ND. See oifp comment in in6_selectsrc(). */ 865 if (oifp != NULL && fibnum == RT_DEFAULT_FIB) { 866 *retifp = oifp; 867 error = 0; 868 } 869 return (error); 870 } 871 872 /* 873 * do not use a rejected or black hole route. 874 * XXX: this check should be done in the L2 output routine. 875 * However, if we skipped this check here, we'd see the following 876 * scenario: 877 * - install a rejected route for a scoped address prefix 878 * (like fe80::/10) 879 * - send a packet to a destination that matches the scoped prefix, 880 * with ambiguity about the scope zone. 881 * - pick the outgoing interface from the route, and disambiguate the 882 * scope zone with the interface. 883 * - ip6_output() would try to get another route with the "new" 884 * destination, which may be valid. 885 * - we'd see no error on output. 886 * Although this may not be very harmful, it should still be confusing. 887 * We thus reject the case here. 888 */ 889 890 if (rt_flags & (RTF_REJECT | RTF_BLACKHOLE)) { 891 error = (rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH); 892 return (error); 893 } 894 895 return (0); 896 } 897 898 /* Public wrapper function to selectroute(). */ 899 int 900 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts, 901 struct ip6_moptions *mopts, struct route_in6 *ro, 902 struct ifnet **retifp, struct rtentry **retrt, u_int fibnum) 903 { 904 905 return (selectroute(dstsock, opts, mopts, ro, retifp, 906 retrt, 0, fibnum)); 907 } 908 909 /* 910 * Default hop limit selection. The precedence is as follows: 911 * 1. Hoplimit value specified via ioctl. 912 * 2. (If the outgoing interface is detected) the current 913 * hop limit of the interface specified by router advertisement. 914 * 3. The system default hoplimit. 915 */ 916 int 917 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp) 918 { 919 920 if (inp && inp->in6p_hops >= 0) 921 return (inp->in6p_hops); 922 else if (ifp) 923 return (ND_IFINFO(ifp)->chlim); 924 else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) { 925 struct nhop6_basic nh6; 926 struct in6_addr dst; 927 uint32_t fibnum, scopeid; 928 int hlim; 929 930 fibnum = inp->inp_inc.inc_fibnum; 931 in6_splitscope(&inp->in6p_faddr, &dst, &scopeid); 932 if (fib6_lookup_nh_basic(fibnum, &dst, scopeid, 0, 0, &nh6)==0){ 933 hlim = ND_IFINFO(nh6.nh_ifp)->chlim; 934 return (hlim); 935 } 936 } 937 return (V_ip6_defhlim); 938 } 939 940 /* 941 * XXX: this is borrowed from in6_pcbbind(). If possible, we should 942 * share this function by all *bsd*... 943 */ 944 int 945 in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct ucred *cred) 946 { 947 struct socket *so = inp->inp_socket; 948 u_int16_t lport = 0; 949 int error, lookupflags = 0; 950 #ifdef INVARIANTS 951 struct inpcbinfo *pcbinfo = inp->inp_pcbinfo; 952 #endif 953 954 INP_WLOCK_ASSERT(inp); 955 INP_HASH_WLOCK_ASSERT(pcbinfo); 956 957 error = prison_local_ip6(cred, laddr, 958 ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)); 959 if (error) 960 return(error); 961 962 /* XXX: this is redundant when called from in6_pcbbind */ 963 if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT|SO_REUSEPORT_LB)) == 0) 964 lookupflags = INPLOOKUP_WILDCARD; 965 966 inp->inp_flags |= INP_ANONPORT; 967 968 error = in_pcb_lport(inp, NULL, &lport, cred, lookupflags); 969 if (error != 0) 970 return (error); 971 972 inp->inp_lport = lport; 973 if (in_pcbinshash(inp) != 0) { 974 inp->in6p_laddr = in6addr_any; 975 inp->inp_lport = 0; 976 return (EAGAIN); 977 } 978 979 return (0); 980 } 981 982 void 983 addrsel_policy_init(void) 984 { 985 986 init_policy_queue(); 987 988 /* initialize the "last resort" policy */ 989 bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy)); 990 V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP; 991 992 if (!IS_DEFAULT_VNET(curvnet)) 993 return; 994 995 ADDRSEL_LOCK_INIT(); 996 ADDRSEL_SXLOCK_INIT(); 997 } 998 999 static struct in6_addrpolicy * 1000 lookup_addrsel_policy(struct sockaddr_in6 *key) 1001 { 1002 struct in6_addrpolicy *match = NULL; 1003 1004 ADDRSEL_LOCK(); 1005 match = match_addrsel_policy(key); 1006 1007 if (match == NULL) 1008 match = &V_defaultaddrpolicy; 1009 else 1010 match->use++; 1011 ADDRSEL_UNLOCK(); 1012 1013 return (match); 1014 } 1015 1016 /* 1017 * Subroutines to manage the address selection policy table via sysctl. 1018 */ 1019 struct walkarg { 1020 struct sysctl_req *w_req; 1021 }; 1022 1023 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS); 1024 SYSCTL_DECL(_net_inet6_ip6); 1025 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy, 1026 CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl, 1027 ""); 1028 1029 static int 1030 in6_src_sysctl(SYSCTL_HANDLER_ARGS) 1031 { 1032 struct walkarg w; 1033 1034 if (req->newptr) 1035 return EPERM; 1036 1037 bzero(&w, sizeof(w)); 1038 w.w_req = req; 1039 1040 return (walk_addrsel_policy(dump_addrsel_policyent, &w)); 1041 } 1042 1043 int 1044 in6_src_ioctl(u_long cmd, caddr_t data) 1045 { 1046 struct in6_addrpolicy ent0; 1047 1048 if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY) 1049 return (EOPNOTSUPP); /* check for safety */ 1050 1051 ent0 = *(struct in6_addrpolicy *)data; 1052 1053 if (ent0.label == ADDR_LABEL_NOTAPP) 1054 return (EINVAL); 1055 /* check if the prefix mask is consecutive. */ 1056 if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0) 1057 return (EINVAL); 1058 /* clear trailing garbages (if any) of the prefix address. */ 1059 IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr); 1060 ent0.use = 0; 1061 1062 switch (cmd) { 1063 case SIOCAADDRCTL_POLICY: 1064 return (add_addrsel_policyent(&ent0)); 1065 case SIOCDADDRCTL_POLICY: 1066 return (delete_addrsel_policyent(&ent0)); 1067 } 1068 1069 return (0); /* XXX: compromise compilers */ 1070 } 1071 1072 /* 1073 * The followings are implementation of the policy table using a 1074 * simple tail queue. 1075 * XXX such details should be hidden. 1076 * XXX implementation using binary tree should be more efficient. 1077 */ 1078 struct addrsel_policyent { 1079 TAILQ_ENTRY(addrsel_policyent) ape_entry; 1080 struct in6_addrpolicy ape_policy; 1081 }; 1082 1083 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent); 1084 1085 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab); 1086 #define V_addrsel_policytab VNET(addrsel_policytab) 1087 1088 static void 1089 init_policy_queue(void) 1090 { 1091 1092 TAILQ_INIT(&V_addrsel_policytab); 1093 } 1094 1095 static int 1096 add_addrsel_policyent(struct in6_addrpolicy *newpolicy) 1097 { 1098 struct addrsel_policyent *new, *pol; 1099 1100 new = malloc(sizeof(*new), M_IFADDR, 1101 M_WAITOK); 1102 ADDRSEL_XLOCK(); 1103 ADDRSEL_LOCK(); 1104 1105 /* duplication check */ 1106 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1107 if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr, 1108 &pol->ape_policy.addr.sin6_addr) && 1109 IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr, 1110 &pol->ape_policy.addrmask.sin6_addr)) { 1111 ADDRSEL_UNLOCK(); 1112 ADDRSEL_XUNLOCK(); 1113 free(new, M_IFADDR); 1114 return (EEXIST); /* or override it? */ 1115 } 1116 } 1117 1118 bzero(new, sizeof(*new)); 1119 1120 /* XXX: should validate entry */ 1121 new->ape_policy = *newpolicy; 1122 1123 TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry); 1124 ADDRSEL_UNLOCK(); 1125 ADDRSEL_XUNLOCK(); 1126 1127 return (0); 1128 } 1129 1130 static int 1131 delete_addrsel_policyent(struct in6_addrpolicy *key) 1132 { 1133 struct addrsel_policyent *pol; 1134 1135 ADDRSEL_XLOCK(); 1136 ADDRSEL_LOCK(); 1137 1138 /* search for the entry in the table */ 1139 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1140 if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr, 1141 &pol->ape_policy.addr.sin6_addr) && 1142 IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr, 1143 &pol->ape_policy.addrmask.sin6_addr)) { 1144 break; 1145 } 1146 } 1147 if (pol == NULL) { 1148 ADDRSEL_UNLOCK(); 1149 ADDRSEL_XUNLOCK(); 1150 return (ESRCH); 1151 } 1152 1153 TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry); 1154 ADDRSEL_UNLOCK(); 1155 ADDRSEL_XUNLOCK(); 1156 free(pol, M_IFADDR); 1157 1158 return (0); 1159 } 1160 1161 static int 1162 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w) 1163 { 1164 struct addrsel_policyent *pol; 1165 int error = 0; 1166 1167 ADDRSEL_SLOCK(); 1168 TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) { 1169 if ((error = (*callback)(&pol->ape_policy, w)) != 0) { 1170 ADDRSEL_SUNLOCK(); 1171 return (error); 1172 } 1173 } 1174 ADDRSEL_SUNLOCK(); 1175 return (error); 1176 } 1177 1178 static int 1179 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg) 1180 { 1181 int error = 0; 1182 struct walkarg *w = arg; 1183 1184 error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol)); 1185 1186 return (error); 1187 } 1188 1189 static struct in6_addrpolicy * 1190 match_addrsel_policy(struct sockaddr_in6 *key) 1191 { 1192 struct addrsel_policyent *pent; 1193 struct in6_addrpolicy *bestpol = NULL, *pol; 1194 int matchlen, bestmatchlen = -1; 1195 u_char *mp, *ep, *k, *p, m; 1196 1197 TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) { 1198 matchlen = 0; 1199 1200 pol = &pent->ape_policy; 1201 mp = (u_char *)&pol->addrmask.sin6_addr; 1202 ep = mp + 16; /* XXX: scope field? */ 1203 k = (u_char *)&key->sin6_addr; 1204 p = (u_char *)&pol->addr.sin6_addr; 1205 for (; mp < ep && *mp; mp++, k++, p++) { 1206 m = *mp; 1207 if ((*k & m) != *p) 1208 goto next; /* not match */ 1209 if (m == 0xff) /* short cut for a typical case */ 1210 matchlen += 8; 1211 else { 1212 while (m >= 0x80) { 1213 matchlen++; 1214 m <<= 1; 1215 } 1216 } 1217 } 1218 1219 /* matched. check if this is better than the current best. */ 1220 if (bestpol == NULL || 1221 matchlen > bestmatchlen) { 1222 bestpol = pol; 1223 bestmatchlen = matchlen; 1224 } 1225 1226 next: 1227 continue; 1228 } 1229 1230 return (bestpol); 1231 } 1232