xref: /freebsd/sys/netinet6/in6_src.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $
30  */
31 
32 /*-
33  * Copyright (c) 1982, 1986, 1991, 1993
34  *	The Regents of the University of California.  All rights reserved.
35  *
36  * Redistribution and use in source and binary forms, with or without
37  * modification, are permitted provided that the following conditions
38  * are met:
39  * 1. Redistributions of source code must retain the above copyright
40  *    notice, this list of conditions and the following disclaimer.
41  * 2. Redistributions in binary form must reproduce the above copyright
42  *    notice, this list of conditions and the following disclaimer in the
43  *    documentation and/or other materials provided with the distribution.
44  * 4. Neither the name of the University nor the names of its contributors
45  *    may be used to endorse or promote products derived from this software
46  *    without specific prior written permission.
47  *
48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58  * SUCH DAMAGE.
59  *
60  *	@(#)in_pcb.c	8.2 (Berkeley) 1/4/94
61  */
62 
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
65 
66 #include "opt_inet.h"
67 #include "opt_inet6.h"
68 #include "opt_mpath.h"
69 
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/sx.h>
86 #include <sys/vimage.h>
87 
88 #include <net/if.h>
89 #include <net/route.h>
90 #include <net/if_llatbl.h>
91 #ifdef RADIX_MPATH
92 #include <net/radix_mpath.h>
93 #endif
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 #include <netinet/vinet.h>
104 
105 #include <netinet6/in6_var.h>
106 #include <netinet/ip6.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 #include <netinet6/vinet6.h>
112 
113 static struct mtx addrsel_lock;
114 #define	ADDRSEL_LOCK_INIT()	mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
115 #define	ADDRSEL_LOCK()		mtx_lock(&addrsel_lock)
116 #define	ADDRSEL_UNLOCK()	mtx_unlock(&addrsel_lock)
117 #define	ADDRSEL_LOCK_ASSERT()	mtx_assert(&addrsel_lock, MA_OWNED)
118 
119 static struct sx addrsel_sxlock;
120 #define	ADDRSEL_SXLOCK_INIT()	sx_init(&addrsel_sxlock, "addrsel_sxlock")
121 #define	ADDRSEL_SLOCK()		sx_slock(&addrsel_sxlock)
122 #define	ADDRSEL_SUNLOCK()	sx_sunlock(&addrsel_sxlock)
123 #define	ADDRSEL_XLOCK()		sx_xlock(&addrsel_sxlock)
124 #define	ADDRSEL_XUNLOCK()	sx_xunlock(&addrsel_sxlock)
125 
126 #define ADDR_LABEL_NOTAPP (-1)
127 
128 #ifdef VIMAGE_GLOBALS
129 struct in6_addrpolicy defaultaddrpolicy;
130 int ip6_prefer_tempaddr;
131 #endif
132 
133 static int selectroute __P((struct sockaddr_in6 *, struct ip6_pktopts *,
134 	struct ip6_moptions *, struct route_in6 *, struct ifnet **,
135 	struct rtentry **, int));
136 static int in6_selectif __P((struct sockaddr_in6 *, struct ip6_pktopts *,
137 	struct ip6_moptions *, struct route_in6 *ro, struct ifnet **));
138 
139 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *);
140 
141 static void init_policy_queue(void);
142 static int add_addrsel_policyent(struct in6_addrpolicy *);
143 static int delete_addrsel_policyent(struct in6_addrpolicy *);
144 static int walk_addrsel_policy __P((int (*)(struct in6_addrpolicy *, void *),
145 				    void *));
146 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *);
147 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
148 
149 /*
150  * Return an IPv6 address, which is the most appropriate for a given
151  * destination and user specified options.
152  * If necessary, this function lookups the routing table and returns
153  * an entry to the caller for later use.
154  */
155 #define REPLACE(r) do {\
156 	if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \
157 		sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
158 		V_ip6stat.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 	if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \
167 		sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
168 		V_ip6stat.ip6s_sources_rule[(r)]++; \
169 	/* { \
170 	char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
171 	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)); \
172 	} */ \
173 	goto next;		/* XXX: we can't use 'continue' here */ \
174 } while(0)
175 #define BREAK(r) do { \
176 	if ((r) < sizeof(V_ip6stat.ip6s_sources_rule) / \
177 		sizeof(V_ip6stat.ip6s_sources_rule[0])) /* check for safety */ \
178 		V_ip6stat.ip6s_sources_rule[(r)]++; \
179 	goto out;		/* XXX: we can't use 'break' here */ \
180 } while(0)
181 
182 struct in6_addr *
183 in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
184     struct inpcb *inp, struct route_in6 *ro, struct ucred *cred,
185     struct ifnet **ifpp, int *errorp)
186 {
187 	INIT_VNET_INET6(curvnet);
188 	struct in6_addr dst;
189 	struct ifnet *ifp = NULL;
190 	struct in6_ifaddr *ia = NULL, *ia_best = NULL;
191 	struct in6_pktinfo *pi = NULL;
192 	int dst_scope = -1, best_scope = -1, best_matchlen = -1;
193 	struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
194 	u_int32_t odstzone;
195 	int prefer_tempaddr;
196 	struct ip6_moptions *mopts;
197 
198 	dst = dstsock->sin6_addr; /* make a copy for local operation */
199 	*errorp = 0;
200 	if (ifpp)
201 		*ifpp = NULL;
202 
203 	if (inp != NULL) {
204 		INP_LOCK_ASSERT(inp);
205 		mopts = inp->in6p_moptions;
206 	} else {
207 		mopts = NULL;
208 	}
209 
210 	/*
211 	 * If the source address is explicitly specified by the caller,
212 	 * check if the requested source address is indeed a unicast address
213 	 * assigned to the node, and can be used as the packet's source
214 	 * address.  If everything is okay, use the address as source.
215 	 */
216 	if (opts && (pi = opts->ip6po_pktinfo) &&
217 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
218 		struct sockaddr_in6 srcsock;
219 		struct in6_ifaddr *ia6;
220 
221 		/* get the outgoing interface */
222 		if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp))
223 		    != 0) {
224 			return (NULL);
225 		}
226 
227 		/*
228 		 * determine the appropriate zone id of the source based on
229 		 * the zone of the destination and the outgoing interface.
230 		 * If the specified address is ambiguous wrt the scope zone,
231 		 * the interface must be specified; otherwise, ifa_ifwithaddr()
232 		 * will fail matching the address.
233 		 */
234 		bzero(&srcsock, sizeof(srcsock));
235 		srcsock.sin6_family = AF_INET6;
236 		srcsock.sin6_len = sizeof(srcsock);
237 		srcsock.sin6_addr = pi->ipi6_addr;
238 		if (ifp) {
239 			*errorp = in6_setscope(&srcsock.sin6_addr, ifp, NULL);
240 			if (*errorp != 0)
241 				return (NULL);
242 		}
243 		if (cred != NULL && (*errorp = prison_local_ip6(cred,
244 		    &srcsock.sin6_addr, (inp != NULL &&
245 		    (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
246 			return (NULL);
247 
248 		ia6 = (struct in6_ifaddr *)ifa_ifwithaddr((struct sockaddr *)(&srcsock));
249 		if (ia6 == NULL ||
250 		    (ia6->ia6_flags & (IN6_IFF_ANYCAST | IN6_IFF_NOTREADY))) {
251 			*errorp = EADDRNOTAVAIL;
252 			return (NULL);
253 		}
254 		pi->ipi6_addr = srcsock.sin6_addr; /* XXX: this overrides pi */
255 		if (ifpp)
256 			*ifpp = ifp;
257 		return (&ia6->ia_addr.sin6_addr);
258 	}
259 
260 	/*
261 	 * Otherwise, if the socket has already bound the source, just use it.
262 	 */
263 	if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
264 		if (cred != NULL &&
265 		    (*errorp = prison_local_ip6(cred, &inp->in6p_laddr,
266 		    ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
267 			return (NULL);
268 		return (&inp->in6p_laddr);
269 	}
270 
271 	/*
272 	 * If the address is not specified, choose the best one based on
273 	 * the outgoing interface and the destination address.
274 	 */
275 	/* get the outgoing interface */
276 	if ((*errorp = in6_selectif(dstsock, opts, mopts, ro, &ifp)) != 0)
277 		return (NULL);
278 
279 #ifdef DIAGNOSTIC
280 	if (ifp == NULL)	/* this should not happen */
281 		panic("in6_selectsrc: NULL ifp");
282 #endif
283 	*errorp = in6_setscope(&dst, ifp, &odstzone);
284 	if (*errorp != 0)
285 		return (NULL);
286 
287 	for (ia = V_in6_ifaddr; ia; ia = ia->ia_next) {
288 		int new_scope = -1, new_matchlen = -1;
289 		struct in6_addrpolicy *new_policy = NULL;
290 		u_int32_t srczone, osrczone, dstzone;
291 		struct in6_addr src;
292 		struct ifnet *ifp1 = ia->ia_ifp;
293 
294 		/*
295 		 * We'll never take an address that breaks the scope zone
296 		 * of the destination.  We also skip an address if its zone
297 		 * does not contain the outgoing interface.
298 		 * XXX: we should probably use sin6_scope_id here.
299 		 */
300 		if (in6_setscope(&dst, ifp1, &dstzone) ||
301 		    odstzone != dstzone) {
302 			continue;
303 		}
304 		src = ia->ia_addr.sin6_addr;
305 		if (in6_setscope(&src, ifp, &osrczone) ||
306 		    in6_setscope(&src, ifp1, &srczone) ||
307 		    osrczone != srczone) {
308 			continue;
309 		}
310 
311 		/* avoid unusable addresses */
312 		if ((ia->ia6_flags &
313 		     (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
314 				continue;
315 		}
316 		if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
317 			continue;
318 
319 		if (cred != NULL &&
320 		    prison_local_ip6(cred, &ia->ia_addr.sin6_addr,
321 			(inp != NULL &&
322 			(inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0)
323 			continue;
324 
325 		/* Rule 1: Prefer same address */
326 		if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) {
327 			ia_best = ia;
328 			BREAK(1); /* there should be no better candidate */
329 		}
330 
331 		if (ia_best == NULL)
332 			REPLACE(0);
333 
334 		/* Rule 2: Prefer appropriate scope */
335 		if (dst_scope < 0)
336 			dst_scope = in6_addrscope(&dst);
337 		new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
338 		if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
339 			if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
340 				REPLACE(2);
341 			NEXT(2);
342 		} else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
343 			if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
344 				NEXT(2);
345 			REPLACE(2);
346 		}
347 
348 		/*
349 		 * Rule 3: Avoid deprecated addresses.  Note that the case of
350 		 * !ip6_use_deprecated is already rejected above.
351 		 */
352 		if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
353 			NEXT(3);
354 		if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
355 			REPLACE(3);
356 
357 		/* Rule 4: Prefer home addresses */
358 		/*
359 		 * XXX: This is a TODO.  We should probably merge the MIP6
360 		 * case above.
361 		 */
362 
363 		/* Rule 5: Prefer outgoing interface */
364 		if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
365 			NEXT(5);
366 		if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
367 			REPLACE(5);
368 
369 		/*
370 		 * Rule 6: Prefer matching label
371 		 * Note that best_policy should be non-NULL here.
372 		 */
373 		if (dst_policy == NULL)
374 			dst_policy = lookup_addrsel_policy(dstsock);
375 		if (dst_policy->label != ADDR_LABEL_NOTAPP) {
376 			new_policy = lookup_addrsel_policy(&ia->ia_addr);
377 			if (dst_policy->label == best_policy->label &&
378 			    dst_policy->label != new_policy->label)
379 				NEXT(6);
380 			if (dst_policy->label != best_policy->label &&
381 			    dst_policy->label == new_policy->label)
382 				REPLACE(6);
383 		}
384 
385 		/*
386 		 * Rule 7: Prefer public addresses.
387 		 * We allow users to reverse the logic by configuring
388 		 * a sysctl variable, so that privacy conscious users can
389 		 * always prefer temporary addresses.
390 		 */
391 		if (opts == NULL ||
392 		    opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
393 			prefer_tempaddr = V_ip6_prefer_tempaddr;
394 		} else if (opts->ip6po_prefer_tempaddr ==
395 		    IP6PO_TEMPADDR_NOTPREFER) {
396 			prefer_tempaddr = 0;
397 		} else
398 			prefer_tempaddr = 1;
399 		if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
400 		    (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
401 			if (prefer_tempaddr)
402 				REPLACE(7);
403 			else
404 				NEXT(7);
405 		}
406 		if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
407 		    !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
408 			if (prefer_tempaddr)
409 				NEXT(7);
410 			else
411 				REPLACE(7);
412 		}
413 
414 		/*
415 		 * Rule 8: prefer addresses on alive interfaces.
416 		 * This is a KAME specific rule.
417 		 */
418 		if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
419 		    !(ia->ia_ifp->if_flags & IFF_UP))
420 			NEXT(8);
421 		if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
422 		    (ia->ia_ifp->if_flags & IFF_UP))
423 			REPLACE(8);
424 
425 		/*
426 		 * Rule 14: Use longest matching prefix.
427 		 * Note: in the address selection draft, this rule is
428 		 * documented as "Rule 8".  However, since it is also
429 		 * documented that this rule can be overridden, we assign
430 		 * a large number so that it is easy to assign smaller numbers
431 		 * to more preferred rules.
432 		 */
433 		new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
434 		if (best_matchlen < new_matchlen)
435 			REPLACE(14);
436 		if (new_matchlen < best_matchlen)
437 			NEXT(14);
438 
439 		/* Rule 15 is reserved. */
440 
441 		/*
442 		 * Last resort: just keep the current candidate.
443 		 * Or, do we need more rules?
444 		 */
445 		continue;
446 
447 	  replace:
448 		ia_best = ia;
449 		best_scope = (new_scope >= 0 ? new_scope :
450 			      in6_addrscope(&ia_best->ia_addr.sin6_addr));
451 		best_policy = (new_policy ? new_policy :
452 			       lookup_addrsel_policy(&ia_best->ia_addr));
453 		best_matchlen = (new_matchlen >= 0 ? new_matchlen :
454 				 in6_matchlen(&ia_best->ia_addr.sin6_addr,
455 					      &dst));
456 
457 	  next:
458 		continue;
459 
460 	  out:
461 		break;
462 	}
463 
464 	if ((ia = ia_best) == NULL) {
465 		*errorp = EADDRNOTAVAIL;
466 		return (NULL);
467 	}
468 
469 	if (ifpp)
470 		*ifpp = ifp;
471 
472 	return (&ia->ia_addr.sin6_addr);
473 }
474 
475 /*
476  * clone - meaningful only for bsdi and freebsd
477  */
478 static int
479 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
480     struct ip6_moptions *mopts, struct route_in6 *ro,
481     struct ifnet **retifp, struct rtentry **retrt, int norouteok)
482 {
483 	INIT_VNET_INET6(curvnet);
484 	int error = 0;
485 	struct ifnet *ifp = NULL;
486 	struct rtentry *rt = NULL;
487 	struct sockaddr_in6 *sin6_next;
488 	struct in6_pktinfo *pi = NULL;
489 	struct in6_addr *dst = &dstsock->sin6_addr;
490 #if 0
491 	char ip6buf[INET6_ADDRSTRLEN];
492 
493 	if (dstsock->sin6_addr.s6_addr32[0] == 0 &&
494 	    dstsock->sin6_addr.s6_addr32[1] == 0 &&
495 	    !IN6_IS_ADDR_LOOPBACK(&dstsock->sin6_addr)) {
496 		printf("in6_selectroute: strange destination %s\n",
497 		       ip6_sprintf(ip6buf, &dstsock->sin6_addr));
498 	} else {
499 		printf("in6_selectroute: destination = %s%%%d\n",
500 		       ip6_sprintf(ip6buf, &dstsock->sin6_addr),
501 		       dstsock->sin6_scope_id); /* for debug */
502 	}
503 #endif
504 
505 	/* If the caller specify the outgoing interface explicitly, use it. */
506 	if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
507 		/* XXX boundary check is assumed to be already done. */
508 		ifp = ifnet_byindex(pi->ipi6_ifindex);
509 		if (ifp != NULL &&
510 		    (norouteok || retrt == NULL ||
511 		    IN6_IS_ADDR_MULTICAST(dst))) {
512 			/*
513 			 * we do not have to check or get the route for
514 			 * multicast.
515 			 */
516 			goto done;
517 		} else
518 			goto getroute;
519 	}
520 
521 	/*
522 	 * If the destination address is a multicast address and the outgoing
523 	 * interface for the address is specified by the caller, use it.
524 	 */
525 	if (IN6_IS_ADDR_MULTICAST(dst) &&
526 	    mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
527 		goto done; /* we do not need a route for multicast. */
528 	}
529 
530   getroute:
531 	/*
532 	 * If the next hop address for the packet is specified by the caller,
533 	 * use it as the gateway.
534 	 */
535 	if (opts && opts->ip6po_nexthop) {
536 		struct route_in6 *ron;
537 		struct llentry *la;
538 
539 		sin6_next = satosin6(opts->ip6po_nexthop);
540 
541 		/* at this moment, we only support AF_INET6 next hops */
542 		if (sin6_next->sin6_family != AF_INET6) {
543 			error = EAFNOSUPPORT; /* or should we proceed? */
544 			goto done;
545 		}
546 
547 		/*
548 		 * If the next hop is an IPv6 address, then the node identified
549 		 * by that address must be a neighbor of the sending host.
550 		 */
551 		ron = &opts->ip6po_nextroute;
552 		/*
553 		 * XXX what do we do here?
554 		 * PLZ to be fixing
555 		 */
556 
557 
558 		if (ron->ro_rt == NULL) {
559 			rtalloc((struct route *)ron); /* multi path case? */
560 			if (ron->ro_rt == NULL) {
561 				if (ron->ro_rt) {
562 					RTFREE(ron->ro_rt);
563 					ron->ro_rt = NULL;
564 				}
565 				error = EHOSTUNREACH;
566 				goto done;
567 			}
568 		}
569 
570 		rt = ron->ro_rt;
571 		ifp = rt->rt_ifp;
572 		IF_AFDATA_LOCK(ifp);
573 		la = lla_lookup(LLTABLE6(ifp), 0, (struct sockaddr *)&sin6_next->sin6_addr);
574 		IF_AFDATA_UNLOCK(ifp);
575 		if (la != NULL)
576 			LLE_RUNLOCK(la);
577 		else {
578 			error = EHOSTUNREACH;
579 			goto done;
580 		}
581 #if 0
582 		if ((ron->ro_rt &&
583 		     (ron->ro_rt->rt_flags & (RTF_UP | RTF_LLINFO)) !=
584 		     (RTF_UP | RTF_LLINFO)) ||
585 		    !IN6_ARE_ADDR_EQUAL(&satosin6(&ron->ro_dst)->sin6_addr,
586 		    &sin6_next->sin6_addr)) {
587 			if (ron->ro_rt) {
588 				RTFREE(ron->ro_rt);
589 				ron->ro_rt = NULL;
590 			}
591 			*satosin6(&ron->ro_dst) = *sin6_next;
592 		}
593 		if (ron->ro_rt == NULL) {
594 			rtalloc((struct route *)ron); /* multi path case? */
595 			if (ron->ro_rt == NULL ||
596 			    !(ron->ro_rt->rt_flags & RTF_LLINFO)) {
597 				if (ron->ro_rt) {
598 					RTFREE(ron->ro_rt);
599 					ron->ro_rt = NULL;
600 				}
601 				error = EHOSTUNREACH;
602 				goto done;
603 			}
604 		}
605 #endif
606 
607 		/*
608 		 * When cloning is required, try to allocate a route to the
609 		 * destination so that the caller can store path MTU
610 		 * information.
611 		 */
612 		goto done;
613 	}
614 
615 	/*
616 	 * Use a cached route if it exists and is valid, else try to allocate
617 	 * a new one.  Note that we should check the address family of the
618 	 * cached destination, in case of sharing the cache with IPv4.
619 	 */
620 	if (ro) {
621 		if (ro->ro_rt &&
622 		    (!(ro->ro_rt->rt_flags & RTF_UP) ||
623 		     ((struct sockaddr *)(&ro->ro_dst))->sa_family != AF_INET6 ||
624 		     !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
625 		     dst))) {
626 			RTFREE(ro->ro_rt);
627 			ro->ro_rt = (struct rtentry *)NULL;
628 		}
629 		if (ro->ro_rt == (struct rtentry *)NULL) {
630 			struct sockaddr_in6 *sa6;
631 
632 			/* No route yet, so try to acquire one */
633 			bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
634 			sa6 = (struct sockaddr_in6 *)&ro->ro_dst;
635 			*sa6 = *dstsock;
636 			sa6->sin6_scope_id = 0;
637 
638 #ifdef RADIX_MPATH
639 				rtalloc_mpath((struct route *)ro,
640 				    ntohl(sa6->sin6_addr.s6_addr32[3]));
641 #else
642 				ro->ro_rt = rtalloc1(&((struct route *)ro)
643 				    ->ro_dst, 0, 0UL);
644 				if (ro->ro_rt)
645 					RT_UNLOCK(ro->ro_rt);
646 #endif
647 		}
648 
649 		/*
650 		 * do not care about the result if we have the nexthop
651 		 * explicitly specified.
652 		 */
653 		if (opts && opts->ip6po_nexthop)
654 			goto done;
655 
656 		if (ro->ro_rt) {
657 			ifp = ro->ro_rt->rt_ifp;
658 
659 			if (ifp == NULL) { /* can this really happen? */
660 				RTFREE(ro->ro_rt);
661 				ro->ro_rt = NULL;
662 			}
663 		}
664 		if (ro->ro_rt == NULL)
665 			error = EHOSTUNREACH;
666 		rt = ro->ro_rt;
667 
668 		/*
669 		 * Check if the outgoing interface conflicts with
670 		 * the interface specified by ipi6_ifindex (if specified).
671 		 * Note that loopback interface is always okay.
672 		 * (this may happen when we are sending a packet to one of
673 		 *  our own addresses.)
674 		 */
675 		if (ifp && opts && opts->ip6po_pktinfo &&
676 		    opts->ip6po_pktinfo->ipi6_ifindex) {
677 			if (!(ifp->if_flags & IFF_LOOPBACK) &&
678 			    ifp->if_index !=
679 			    opts->ip6po_pktinfo->ipi6_ifindex) {
680 				error = EHOSTUNREACH;
681 				goto done;
682 			}
683 		}
684 	}
685 
686   done:
687 	if (ifp == NULL && rt == NULL) {
688 		/*
689 		 * This can happen if the caller did not pass a cached route
690 		 * nor any other hints.  We treat this case an error.
691 		 */
692 		error = EHOSTUNREACH;
693 	}
694 	if (error == EHOSTUNREACH)
695 		V_ip6stat.ip6s_noroute++;
696 
697 	if (retifp != NULL)
698 		*retifp = ifp;
699 	if (retrt != NULL)
700 		*retrt = rt;	/* rt may be NULL */
701 
702 	return (error);
703 }
704 
705 static int
706 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
707     struct ip6_moptions *mopts, struct route_in6 *ro, struct ifnet **retifp)
708 {
709 	int error;
710 	struct route_in6 sro;
711 	struct rtentry *rt = NULL;
712 
713 	if (ro == NULL) {
714 		bzero(&sro, sizeof(sro));
715 		ro = &sro;
716 	}
717 
718 	if ((error = selectroute(dstsock, opts, mopts, ro, retifp,
719 				     &rt, 1)) != 0) {
720 		if (ro == &sro && rt && rt == sro.ro_rt)
721 			RTFREE(rt);
722 		return (error);
723 	}
724 
725 	/*
726 	 * do not use a rejected or black hole route.
727 	 * XXX: this check should be done in the L2 output routine.
728 	 * However, if we skipped this check here, we'd see the following
729 	 * scenario:
730 	 * - install a rejected route for a scoped address prefix
731 	 *   (like fe80::/10)
732 	 * - send a packet to a destination that matches the scoped prefix,
733 	 *   with ambiguity about the scope zone.
734 	 * - pick the outgoing interface from the route, and disambiguate the
735 	 *   scope zone with the interface.
736 	 * - ip6_output() would try to get another route with the "new"
737 	 *   destination, which may be valid.
738 	 * - we'd see no error on output.
739 	 * Although this may not be very harmful, it should still be confusing.
740 	 * We thus reject the case here.
741 	 */
742 	if (rt && (rt->rt_flags & (RTF_REJECT | RTF_BLACKHOLE))) {
743 		int flags = (rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
744 
745 		if (ro == &sro && rt && rt == sro.ro_rt)
746 			RTFREE(rt);
747 		return (flags);
748 	}
749 
750 	/*
751 	 * Adjust the "outgoing" interface.  If we're going to loop the packet
752 	 * back to ourselves, the ifp would be the loopback interface.
753 	 * However, we'd rather know the interface associated to the
754 	 * destination address (which should probably be one of our own
755 	 * addresses.)
756 	 */
757 	if (rt && rt->rt_ifa && rt->rt_ifa->ifa_ifp)
758 		*retifp = rt->rt_ifa->ifa_ifp;
759 
760 	if (ro == &sro && rt && rt == sro.ro_rt)
761 		RTFREE(rt);
762 	return (0);
763 }
764 
765 /*
766  * clone - meaningful only for bsdi and freebsd
767  */
768 int
769 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
770     struct ip6_moptions *mopts, struct route_in6 *ro,
771     struct ifnet **retifp, struct rtentry **retrt)
772 {
773 
774 	return (selectroute(dstsock, opts, mopts, ro, retifp,
775 	    retrt, 0));
776 }
777 
778 /*
779  * Default hop limit selection. The precedence is as follows:
780  * 1. Hoplimit value specified via ioctl.
781  * 2. (If the outgoing interface is detected) the current
782  *     hop limit of the interface specified by router advertisement.
783  * 3. The system default hoplimit.
784  */
785 int
786 in6_selecthlim(struct inpcb *in6p, struct ifnet *ifp)
787 {
788 	INIT_VNET_INET6(curvnet);
789 
790 	if (in6p && in6p->in6p_hops >= 0)
791 		return (in6p->in6p_hops);
792 	else if (ifp)
793 		return (ND_IFINFO(ifp)->chlim);
794 	else if (in6p && !IN6_IS_ADDR_UNSPECIFIED(&in6p->in6p_faddr)) {
795 		struct route_in6 ro6;
796 		struct ifnet *lifp;
797 
798 		bzero(&ro6, sizeof(ro6));
799 		ro6.ro_dst.sin6_family = AF_INET6;
800 		ro6.ro_dst.sin6_len = sizeof(struct sockaddr_in6);
801 		ro6.ro_dst.sin6_addr = in6p->in6p_faddr;
802 		rtalloc((struct route *)&ro6);
803 		if (ro6.ro_rt) {
804 			lifp = ro6.ro_rt->rt_ifp;
805 			RTFREE(ro6.ro_rt);
806 			if (lifp)
807 				return (ND_IFINFO(lifp)->chlim);
808 		} else
809 			return (V_ip6_defhlim);
810 	}
811 	return (V_ip6_defhlim);
812 }
813 
814 /*
815  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
816  * share this function by all *bsd*...
817  */
818 int
819 in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct ucred *cred)
820 {
821 	INIT_VNET_INET(curvnet);
822 	struct socket *so = inp->inp_socket;
823 	u_int16_t lport = 0, first, last, *lastport;
824 	int count, error, wild = 0, dorandom;
825 	struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
826 
827 	INP_INFO_WLOCK_ASSERT(pcbinfo);
828 	INP_WLOCK_ASSERT(inp);
829 
830 	error = prison_local_ip6(cred, laddr,
831 	    ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0));
832 	if (error)
833 		return(error);
834 
835 	/* XXX: this is redundant when called from in6_pcbbind */
836 	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
837 		wild = INPLOOKUP_WILDCARD;
838 
839 	inp->inp_flags |= INP_ANONPORT;
840 
841 	if (inp->inp_flags & INP_HIGHPORT) {
842 		first = V_ipport_hifirstauto;	/* sysctl */
843 		last  = V_ipport_hilastauto;
844 		lastport = &pcbinfo->ipi_lasthi;
845 	} else if (inp->inp_flags & INP_LOWPORT) {
846 		error = priv_check_cred(cred, PRIV_NETINET_RESERVEDPORT, 0);
847 		if (error)
848 			return error;
849 		first = V_ipport_lowfirstauto;	/* 1023 */
850 		last  = V_ipport_lowlastauto;	/* 600 */
851 		lastport = &pcbinfo->ipi_lastlow;
852 	} else {
853 		first = V_ipport_firstauto;	/* sysctl */
854 		last  = V_ipport_lastauto;
855 		lastport = &pcbinfo->ipi_lastport;
856 	}
857 
858 	/*
859 	 * For UDP, use random port allocation as long as the user
860 	 * allows it.  For TCP (and as of yet unknown) connections,
861 	 * use random port allocation only if the user allows it AND
862 	 * ipport_tick() allows it.
863 	 */
864 	if (V_ipport_randomized &&
865 	    (!V_ipport_stoprandom || pcbinfo == &V_udbinfo))
866 		dorandom = 1;
867 	else
868 		dorandom = 0;
869 	/*
870 	 * It makes no sense to do random port allocation if
871 	 * we have the only port available.
872 	 */
873 	if (first == last)
874 		dorandom = 0;
875 	/* Make sure to not include UDP packets in the count. */
876 	if (pcbinfo != &V_udbinfo)
877 		V_ipport_tcpallocs++;
878 
879 	/*
880 	 * Instead of having two loops further down counting up or down
881 	 * make sure that first is always <= last and go with only one
882 	 * code path implementing all logic.
883 	 */
884 	if (first > last) {
885 		u_int16_t aux;
886 
887 		aux = first;
888 		first = last;
889 		last = aux;
890 	}
891 
892 	if (dorandom)
893 		*lastport = first + (arc4random() % (last - first));
894 
895 	count = last - first;
896 
897 	do {
898 		if (count-- < 0) {	/* completely used? */
899 			/* Undo an address bind that may have occurred. */
900 			inp->in6p_laddr = in6addr_any;
901 			return (EADDRNOTAVAIL);
902 		}
903 		++*lastport;
904 		if (*lastport < first || *lastport > last)
905 			*lastport = first;
906 		lport = htons(*lastport);
907 	} while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
908 	    lport, wild, cred));
909 
910 	inp->inp_lport = lport;
911 	if (in_pcbinshash(inp) != 0) {
912 		inp->in6p_laddr = in6addr_any;
913 		inp->inp_lport = 0;
914 		return (EAGAIN);
915 	}
916 
917 	return (0);
918 }
919 
920 void
921 addrsel_policy_init(void)
922 {
923 	ADDRSEL_LOCK_INIT();
924 	ADDRSEL_SXLOCK_INIT();
925 	INIT_VNET_INET6(curvnet);
926 
927 	V_ip6_prefer_tempaddr = 0;
928 
929 	init_policy_queue();
930 
931 	/* initialize the "last resort" policy */
932 	bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy));
933 	V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
934 }
935 
936 static struct in6_addrpolicy *
937 lookup_addrsel_policy(struct sockaddr_in6 *key)
938 {
939 	INIT_VNET_INET6(curvnet);
940 	struct in6_addrpolicy *match = NULL;
941 
942 	ADDRSEL_LOCK();
943 	match = match_addrsel_policy(key);
944 
945 	if (match == NULL)
946 		match = &V_defaultaddrpolicy;
947 	else
948 		match->use++;
949 	ADDRSEL_UNLOCK();
950 
951 	return (match);
952 }
953 
954 /*
955  * Subroutines to manage the address selection policy table via sysctl.
956  */
957 struct walkarg {
958 	struct sysctl_req *w_req;
959 };
960 
961 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
962 SYSCTL_DECL(_net_inet6_ip6);
963 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
964 	CTLFLAG_RD, in6_src_sysctl, "");
965 
966 static int
967 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
968 {
969 	struct walkarg w;
970 
971 	if (req->newptr)
972 		return EPERM;
973 
974 	bzero(&w, sizeof(w));
975 	w.w_req = req;
976 
977 	return (walk_addrsel_policy(dump_addrsel_policyent, &w));
978 }
979 
980 int
981 in6_src_ioctl(u_long cmd, caddr_t data)
982 {
983 	int i;
984 	struct in6_addrpolicy ent0;
985 
986 	if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
987 		return (EOPNOTSUPP); /* check for safety */
988 
989 	ent0 = *(struct in6_addrpolicy *)data;
990 
991 	if (ent0.label == ADDR_LABEL_NOTAPP)
992 		return (EINVAL);
993 	/* check if the prefix mask is consecutive. */
994 	if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
995 		return (EINVAL);
996 	/* clear trailing garbages (if any) of the prefix address. */
997 	for (i = 0; i < 4; i++) {
998 		ent0.addr.sin6_addr.s6_addr32[i] &=
999 			ent0.addrmask.sin6_addr.s6_addr32[i];
1000 	}
1001 	ent0.use = 0;
1002 
1003 	switch (cmd) {
1004 	case SIOCAADDRCTL_POLICY:
1005 		return (add_addrsel_policyent(&ent0));
1006 	case SIOCDADDRCTL_POLICY:
1007 		return (delete_addrsel_policyent(&ent0));
1008 	}
1009 
1010 	return (0);		/* XXX: compromise compilers */
1011 }
1012 
1013 /*
1014  * The followings are implementation of the policy table using a
1015  * simple tail queue.
1016  * XXX such details should be hidden.
1017  * XXX implementation using binary tree should be more efficient.
1018  */
1019 struct addrsel_policyent {
1020 	TAILQ_ENTRY(addrsel_policyent) ape_entry;
1021 	struct in6_addrpolicy ape_policy;
1022 };
1023 
1024 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
1025 
1026 #ifdef VIMAGE_GLOBALS
1027 struct addrsel_policyhead addrsel_policytab;
1028 #endif
1029 
1030 static void
1031 init_policy_queue(void)
1032 {
1033 	INIT_VNET_INET6(curvnet);
1034 
1035 	TAILQ_INIT(&V_addrsel_policytab);
1036 }
1037 
1038 static int
1039 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
1040 {
1041 	INIT_VNET_INET6(curvnet);
1042 	struct addrsel_policyent *new, *pol;
1043 
1044 	new = malloc(sizeof(*new), M_IFADDR,
1045 	       M_WAITOK);
1046 	ADDRSEL_XLOCK();
1047 	ADDRSEL_LOCK();
1048 
1049 	/* duplication check */
1050 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1051 		if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr,
1052 				       &pol->ape_policy.addr.sin6_addr) &&
1053 		    IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr,
1054 				       &pol->ape_policy.addrmask.sin6_addr)) {
1055 			ADDRSEL_UNLOCK();
1056 			ADDRSEL_XUNLOCK();
1057 			free(new, M_IFADDR);
1058 			return (EEXIST);	/* or override it? */
1059 		}
1060 	}
1061 
1062 	bzero(new, sizeof(*new));
1063 
1064 	/* XXX: should validate entry */
1065 	new->ape_policy = *newpolicy;
1066 
1067 	TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry);
1068 	ADDRSEL_UNLOCK();
1069 	ADDRSEL_XUNLOCK();
1070 
1071 	return (0);
1072 }
1073 
1074 static int
1075 delete_addrsel_policyent(struct in6_addrpolicy *key)
1076 {
1077 	INIT_VNET_INET6(curvnet);
1078 	struct addrsel_policyent *pol;
1079 
1080 	ADDRSEL_XLOCK();
1081 	ADDRSEL_LOCK();
1082 
1083 	/* search for the entry in the table */
1084 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1085 		if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr,
1086 		    &pol->ape_policy.addr.sin6_addr) &&
1087 		    IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr,
1088 		    &pol->ape_policy.addrmask.sin6_addr)) {
1089 			break;
1090 		}
1091 	}
1092 	if (pol == NULL) {
1093 		ADDRSEL_UNLOCK();
1094 		ADDRSEL_XUNLOCK();
1095 		return (ESRCH);
1096 	}
1097 
1098 	TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry);
1099 	ADDRSEL_UNLOCK();
1100 	ADDRSEL_XUNLOCK();
1101 
1102 	return (0);
1103 }
1104 
1105 static int
1106 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *),
1107     void *w)
1108 {
1109 	INIT_VNET_INET6(curvnet);
1110 	struct addrsel_policyent *pol;
1111 	int error = 0;
1112 
1113 	ADDRSEL_SLOCK();
1114 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1115 		if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
1116 			ADDRSEL_SUNLOCK();
1117 			return (error);
1118 		}
1119 	}
1120 	ADDRSEL_SUNLOCK();
1121 	return (error);
1122 }
1123 
1124 static int
1125 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
1126 {
1127 	int error = 0;
1128 	struct walkarg *w = arg;
1129 
1130 	error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
1131 
1132 	return (error);
1133 }
1134 
1135 static struct in6_addrpolicy *
1136 match_addrsel_policy(struct sockaddr_in6 *key)
1137 {
1138 	INIT_VNET_INET6(curvnet);
1139 	struct addrsel_policyent *pent;
1140 	struct in6_addrpolicy *bestpol = NULL, *pol;
1141 	int matchlen, bestmatchlen = -1;
1142 	u_char *mp, *ep, *k, *p, m;
1143 
1144 	TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) {
1145 		matchlen = 0;
1146 
1147 		pol = &pent->ape_policy;
1148 		mp = (u_char *)&pol->addrmask.sin6_addr;
1149 		ep = mp + 16;	/* XXX: scope field? */
1150 		k = (u_char *)&key->sin6_addr;
1151 		p = (u_char *)&pol->addr.sin6_addr;
1152 		for (; mp < ep && *mp; mp++, k++, p++) {
1153 			m = *mp;
1154 			if ((*k & m) != *p)
1155 				goto next; /* not match */
1156 			if (m == 0xff) /* short cut for a typical case */
1157 				matchlen += 8;
1158 			else {
1159 				while (m >= 0x80) {
1160 					matchlen++;
1161 					m <<= 1;
1162 				}
1163 			}
1164 		}
1165 
1166 		/* matched.  check if this is better than the current best. */
1167 		if (bestpol == NULL ||
1168 		    matchlen > bestmatchlen) {
1169 			bestpol = pol;
1170 			bestmatchlen = matchlen;
1171 		}
1172 
1173 	  next:
1174 		continue;
1175 	}
1176 
1177 	return (bestpol);
1178 }
1179