xref: /freebsd/sys/netinet6/in6_src.c (revision 716acd9367df49d44f29eeb783706025f3a04c65)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	$KAME: in6_src.c,v 1.132 2003/08/26 04:42:27 keiichi Exp $
32  */
33 
34 /*-
35  * Copyright (c) 1982, 1986, 1991, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. Neither the name of the University nor the names of its contributors
47  *    may be used to endorse or promote products derived from this software
48  *    without specific prior written permission.
49  *
50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
60  * SUCH DAMAGE.
61  */
62 
63 #include <sys/cdefs.h>
64 #include "opt_inet.h"
65 #include "opt_inet6.h"
66 #include <sys/param.h>
67 #include <sys/systm.h>
68 #include <sys/lock.h>
69 #include <sys/malloc.h>
70 #include <sys/mbuf.h>
71 #include <sys/priv.h>
72 #include <sys/protosw.h>
73 #include <sys/socket.h>
74 #include <sys/socketvar.h>
75 #include <sys/sockio.h>
76 #include <sys/sysctl.h>
77 #include <sys/errno.h>
78 #include <sys/time.h>
79 #include <sys/jail.h>
80 #include <sys/kernel.h>
81 #include <sys/rmlock.h>
82 #include <sys/sx.h>
83 
84 #include <net/if.h>
85 #include <net/if_var.h>
86 #include <net/if_dl.h>
87 #include <net/if_private.h>
88 #include <net/route.h>
89 #include <net/route/nhop.h>
90 #include <net/if_llatbl.h>
91 
92 #include <netinet/in.h>
93 #include <netinet/in_var.h>
94 #include <netinet/in_systm.h>
95 #include <netinet/ip.h>
96 #include <netinet/in_pcb.h>
97 #include <netinet/ip_var.h>
98 #include <netinet/udp.h>
99 #include <netinet/udp_var.h>
100 
101 #include <netinet6/in6_var.h>
102 #include <netinet/ip6.h>
103 #include <netinet6/in6_fib.h>
104 #include <netinet6/in6_pcb.h>
105 #include <netinet6/ip6_var.h>
106 #include <netinet6/scope6_var.h>
107 #include <netinet6/nd6.h>
108 
109 static struct mtx addrsel_lock;
110 #define	ADDRSEL_LOCK_INIT()	mtx_init(&addrsel_lock, "addrsel_lock", NULL, MTX_DEF)
111 #define	ADDRSEL_LOCK()		mtx_lock(&addrsel_lock)
112 #define	ADDRSEL_UNLOCK()	mtx_unlock(&addrsel_lock)
113 #define	ADDRSEL_LOCK_ASSERT()	mtx_assert(&addrsel_lock, MA_OWNED)
114 
115 static struct sx addrsel_sxlock;
116 #define	ADDRSEL_SXLOCK_INIT()	sx_init(&addrsel_sxlock, "addrsel_sxlock")
117 #define	ADDRSEL_SLOCK()		sx_slock(&addrsel_sxlock)
118 #define	ADDRSEL_SUNLOCK()	sx_sunlock(&addrsel_sxlock)
119 #define	ADDRSEL_XLOCK()		sx_xlock(&addrsel_sxlock)
120 #define	ADDRSEL_XUNLOCK()	sx_xunlock(&addrsel_sxlock)
121 
122 #define ADDR_LABEL_NOTAPP (-1)
123 VNET_DEFINE_STATIC(struct in6_addrpolicy, defaultaddrpolicy);
124 #define	V_defaultaddrpolicy		VNET(defaultaddrpolicy)
125 
126 VNET_DEFINE(int, ip6_prefer_tempaddr) = 0;
127 
128 static int selectroute(struct sockaddr_in6 *, struct ip6_pktopts *,
129 	struct ip6_moptions *, struct route_in6 *, struct ifnet **,
130 	struct nhop_object **, int, u_int, uint32_t);
131 static int in6_selectif(struct sockaddr_in6 *, struct ip6_pktopts *,
132 	struct ip6_moptions *, struct ifnet **,
133 	struct ifnet *, u_int);
134 static int in6_selectsrc(uint32_t, struct sockaddr_in6 *,
135 	struct ip6_pktopts *, struct ip6_moptions *, struct inpcb *,
136 	struct ucred *, struct ifnet **, struct in6_addr *);
137 
138 static struct in6_addrpolicy *lookup_addrsel_policy(struct sockaddr_in6 *);
139 
140 static void init_policy_queue(void);
141 static int add_addrsel_policyent(struct in6_addrpolicy *);
142 static int delete_addrsel_policyent(struct in6_addrpolicy *);
143 static int walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *),
144 	void *);
145 static int dump_addrsel_policyent(struct in6_addrpolicy *, void *);
146 static struct in6_addrpolicy *match_addrsel_policy(struct sockaddr_in6 *);
147 
148 /*
149  * Return an IPv6 address, which is the most appropriate for a given
150  * destination and user specified options.
151  * If necessary, this function lookups the routing table and returns
152  * an entry to the caller for later use.
153  */
154 #define REPLACE(r) do {\
155 	IP6STAT_INC2(ip6s_sources_rule, (r)); \
156 	/* { \
157 	char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
158 	printf("in6_selectsrc: replace %s with %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
159 	} */ \
160 	goto replace; \
161 } while(0)
162 #define NEXT(r) do {\
163 	/* { \
164 	char ip6buf[INET6_ADDRSTRLEN], ip6b[INET6_ADDRSTRLEN]; \
165 	printf("in6_selectsrc: keep %s against %s by %d\n", ia_best ? ip6_sprintf(ip6buf, &ia_best->ia_addr.sin6_addr) : "none", ip6_sprintf(ip6b, &ia->ia_addr.sin6_addr), (r)); \
166 	} */ \
167 	goto next;		/* XXX: we can't use 'continue' here */ \
168 } while(0)
169 #define BREAK(r) do { \
170 	IP6STAT_INC2(ip6s_sources_rule, (r)); \
171 	goto out;		/* XXX: we can't use 'break' here */ \
172 } while(0)
173 
174 static int
in6_selectsrc(uint32_t fibnum,struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct inpcb * inp,struct ucred * cred,struct ifnet ** ifpp,struct in6_addr * srcp)175 in6_selectsrc(uint32_t fibnum, struct sockaddr_in6 *dstsock,
176     struct ip6_pktopts *opts, struct ip6_moptions *mopts, struct inpcb *inp,
177     struct ucred *cred, struct ifnet **ifpp, struct in6_addr *srcp)
178 {
179 	struct rm_priotracker in6_ifa_tracker;
180 	struct in6_addr dst, tmp;
181 	struct ifnet *ifp = NULL, *oifp = NULL;
182 	struct in6_ifaddr *ia = NULL, *ia_best = NULL;
183 	struct in6_pktinfo *pi = NULL;
184 	int dst_scope = -1, best_scope = -1, best_matchlen = -1;
185 	struct in6_addrpolicy *dst_policy = NULL, *best_policy = NULL;
186 	u_int32_t odstzone;
187 	int prefer_tempaddr;
188 	int error;
189 
190 	NET_EPOCH_ASSERT();
191 	KASSERT(srcp != NULL, ("%s: srcp is NULL", __func__));
192 
193 	dst = dstsock->sin6_addr; /* make a copy for local operation */
194 	if (ifpp) {
195 		/*
196 		 * Save a possibly passed in ifp for in6_selectsrc. Only
197 		 * neighbor discovery code should use this feature, where
198 		 * we may know the interface but not the FIB number holding
199 		 * the connected subnet in case someone deleted it from the
200 		 * default FIB and we need to check the interface.
201 		 */
202 		if (*ifpp != NULL)
203 			oifp = *ifpp;
204 		*ifpp = NULL;
205 	}
206 
207 	/*
208 	 * If the source address is explicitly specified by the caller,
209 	 * check if the requested source address is indeed a unicast address
210 	 * assigned to the node, and can be used as the packet's source
211 	 * address.  If everything is okay, use the address as source.
212 	 */
213 	if (opts && (pi = opts->ip6po_pktinfo) &&
214 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
215 		/* get the outgoing interface */
216 		if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
217 		    fibnum))
218 		    != 0)
219 			return (error);
220 
221 		/*
222 		 * determine the appropriate zone id of the source based on
223 		 * the zone of the destination and the outgoing interface.
224 		 * If the specified address is ambiguous wrt the scope zone,
225 		 * the interface must be specified; otherwise, ifa_ifwithaddr()
226 		 * will fail matching the address.
227 		 */
228 		tmp = pi->ipi6_addr;
229 		if (ifp) {
230 			error = in6_setscope(&tmp, ifp, &odstzone);
231 			if (error)
232 				return (error);
233 		}
234 		if (cred != NULL && (error = prison_local_ip6(cred,
235 		    &tmp, (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0)
236 			return (error);
237 
238 		/*
239 		 * If IPV6_BINDANY socket option is set, we allow to specify
240 		 * non local addresses as source address in IPV6_PKTINFO
241 		 * ancillary data.
242 		 */
243 		if ((inp->inp_flags & INP_BINDANY) == 0) {
244 			ia = in6ifa_ifwithaddr(&tmp, 0 /* XXX */, false);
245 			if (ia == NULL || (ia->ia6_flags & (IN6_IFF_ANYCAST |
246 			    IN6_IFF_NOTREADY)))
247 				return (EADDRNOTAVAIL);
248 			bcopy(&ia->ia_addr.sin6_addr, srcp, sizeof(*srcp));
249 		} else
250 			bcopy(&tmp, srcp, sizeof(*srcp));
251 		pi->ipi6_addr = tmp; /* XXX: this overrides pi */
252 		if (ifpp)
253 			*ifpp = ifp;
254 		return (0);
255 	}
256 
257 	/*
258 	 * Otherwise, if the socket has already bound the source, just use it.
259 	 */
260 	if (inp != NULL && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
261 		if (cred != NULL &&
262 		    (error = prison_local_ip6(cred, &inp->in6p_laddr,
263 		    ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0))) != 0)
264 			return (error);
265 		bcopy(&inp->in6p_laddr, srcp, sizeof(*srcp));
266 		return (0);
267 	}
268 
269 	/*
270 	 * Bypass source address selection and use the primary jail IP
271 	 * if requested.
272 	 */
273 	if (cred != NULL && !prison_saddrsel_ip6(cred, srcp))
274 		return (0);
275 
276 	/*
277 	 * If the address is not specified, choose the best one based on
278 	 * the outgoing interface and the destination address.
279 	 */
280 	/* get the outgoing interface */
281 	if ((error = in6_selectif(dstsock, opts, mopts, &ifp, oifp,
282 	    (inp != NULL) ? inp->inp_inc.inc_fibnum : fibnum)) != 0)
283 		return (error);
284 
285 #ifdef DIAGNOSTIC
286 	if (ifp == NULL)	/* this should not happen */
287 		panic("in6_selectsrc: NULL ifp");
288 #endif
289 	error = in6_setscope(&dst, ifp, &odstzone);
290 	if (error)
291 		return (error);
292 
293 	IN6_IFADDR_RLOCK(&in6_ifa_tracker);
294 	CK_STAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
295 		int new_scope = -1, new_matchlen = -1;
296 		struct in6_addrpolicy *new_policy = NULL;
297 		u_int32_t srczone, osrczone, dstzone;
298 		struct in6_addr src;
299 		struct ifnet *ifp1 = ia->ia_ifp;
300 
301 		/*
302 		 * We'll never take an address that breaks the scope zone
303 		 * of the destination.  We also skip an address if its zone
304 		 * does not contain the outgoing interface.
305 		 * XXX: we should probably use sin6_scope_id here.
306 		 */
307 		if (in6_setscope(&dst, ifp1, &dstzone) ||
308 		    odstzone != dstzone) {
309 			continue;
310 		}
311 		src = ia->ia_addr.sin6_addr;
312 		if (in6_setscope(&src, ifp, &osrczone) ||
313 		    in6_setscope(&src, ifp1, &srczone) ||
314 		    osrczone != srczone) {
315 			continue;
316 		}
317 
318 		/* avoid unusable addresses */
319 		if ((ia->ia6_flags &
320 		     (IN6_IFF_NOTREADY | IN6_IFF_ANYCAST | IN6_IFF_DETACHED))) {
321 				continue;
322 		}
323 		if (!V_ip6_use_deprecated && IFA6_IS_DEPRECATED(ia))
324 			continue;
325 
326 		/* If jailed only take addresses of the jail into account. */
327 		if (cred != NULL &&
328 		    prison_check_ip6(cred, &ia->ia_addr.sin6_addr) != 0)
329 			continue;
330 
331 		/* Rule 1: Prefer same address */
332 		if (IN6_ARE_ADDR_EQUAL(&dst, &ia->ia_addr.sin6_addr)) {
333 			ia_best = ia;
334 			BREAK(1); /* there should be no better candidate */
335 		}
336 
337 		if (ia_best == NULL)
338 			REPLACE(0);
339 
340 		/* Rule 2: Prefer appropriate scope */
341 		if (dst_scope < 0)
342 			dst_scope = in6_addrscope(&dst);
343 		new_scope = in6_addrscope(&ia->ia_addr.sin6_addr);
344 		if (IN6_ARE_SCOPE_CMP(best_scope, new_scope) < 0) {
345 			if (IN6_ARE_SCOPE_CMP(best_scope, dst_scope) < 0)
346 				REPLACE(2);
347 			NEXT(2);
348 		} else if (IN6_ARE_SCOPE_CMP(new_scope, best_scope) < 0) {
349 			if (IN6_ARE_SCOPE_CMP(new_scope, dst_scope) < 0)
350 				NEXT(2);
351 			REPLACE(2);
352 		}
353 
354 		/*
355 		 * Rule 3: Avoid deprecated addresses.  Note that the case of
356 		 * !ip6_use_deprecated is already rejected above.
357 		 */
358 		if (!IFA6_IS_DEPRECATED(ia_best) && IFA6_IS_DEPRECATED(ia))
359 			NEXT(3);
360 		if (IFA6_IS_DEPRECATED(ia_best) && !IFA6_IS_DEPRECATED(ia))
361 			REPLACE(3);
362 
363 		/* Rule 4: Prefer home addresses */
364 		/*
365 		 * XXX: This is a TODO.  We should probably merge the MIP6
366 		 * case above.
367 		 */
368 
369 		/* Rule 5: Prefer outgoing interface */
370 		if (!(ND_IFINFO(ifp)->flags & ND6_IFF_NO_PREFER_IFACE)) {
371 			if (ia_best->ia_ifp == ifp && ia->ia_ifp != ifp)
372 				NEXT(5);
373 			if (ia_best->ia_ifp != ifp && ia->ia_ifp == ifp)
374 				REPLACE(5);
375 		}
376 
377 		/*
378 		 * Rule 6: Prefer matching label
379 		 * Note that best_policy should be non-NULL here.
380 		 */
381 		if (dst_policy == NULL)
382 			dst_policy = lookup_addrsel_policy(dstsock);
383 		if (dst_policy->label != ADDR_LABEL_NOTAPP) {
384 			new_policy = lookup_addrsel_policy(&ia->ia_addr);
385 			if (dst_policy->label == best_policy->label &&
386 			    dst_policy->label != new_policy->label)
387 				NEXT(6);
388 			if (dst_policy->label != best_policy->label &&
389 			    dst_policy->label == new_policy->label)
390 				REPLACE(6);
391 		}
392 
393 		/*
394 		 * Rule 7: Prefer public addresses.
395 		 * We allow users to reverse the logic by configuring
396 		 * a sysctl variable, so that privacy conscious users can
397 		 * always prefer temporary addresses.
398 		 */
399 		if (opts == NULL ||
400 		    opts->ip6po_prefer_tempaddr == IP6PO_TEMPADDR_SYSTEM) {
401 			prefer_tempaddr = V_ip6_prefer_tempaddr;
402 		} else if (opts->ip6po_prefer_tempaddr ==
403 		    IP6PO_TEMPADDR_NOTPREFER) {
404 			prefer_tempaddr = 0;
405 		} else
406 			prefer_tempaddr = 1;
407 		if (!(ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
408 		    (ia->ia6_flags & IN6_IFF_TEMPORARY)) {
409 			if (prefer_tempaddr)
410 				REPLACE(7);
411 			else
412 				NEXT(7);
413 		}
414 		if ((ia_best->ia6_flags & IN6_IFF_TEMPORARY) &&
415 		    !(ia->ia6_flags & IN6_IFF_TEMPORARY)) {
416 			if (prefer_tempaddr)
417 				NEXT(7);
418 			else
419 				REPLACE(7);
420 		}
421 
422 		/*
423 		 * Rule 8: prefer addresses on alive interfaces.
424 		 * This is a KAME specific rule.
425 		 */
426 		if ((ia_best->ia_ifp->if_flags & IFF_UP) &&
427 		    !(ia->ia_ifp->if_flags & IFF_UP))
428 			NEXT(8);
429 		if (!(ia_best->ia_ifp->if_flags & IFF_UP) &&
430 		    (ia->ia_ifp->if_flags & IFF_UP))
431 			REPLACE(8);
432 
433 		/*
434 		 * Rule 9: prefer address with better virtual status.
435 		 */
436 		if (ifa_preferred(&ia_best->ia_ifa, &ia->ia_ifa))
437 			REPLACE(9);
438 		if (ifa_preferred(&ia->ia_ifa, &ia_best->ia_ifa))
439 			NEXT(9);
440 
441 		/*
442 		 * Rule 10: prefer address with `prefer_source' flag.
443 		 */
444 		if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0 &&
445 		    (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0)
446 			REPLACE(10);
447 		if ((ia_best->ia6_flags & IN6_IFF_PREFER_SOURCE) != 0 &&
448 		    (ia->ia6_flags & IN6_IFF_PREFER_SOURCE) == 0)
449 			NEXT(10);
450 
451 		/*
452 		 * Rule 14: Use longest matching prefix.
453 		 * Note: in the address selection draft, this rule is
454 		 * documented as "Rule 8".  However, since it is also
455 		 * documented that this rule can be overridden, we assign
456 		 * a large number so that it is easy to assign smaller numbers
457 		 * to more preferred rules.
458 		 */
459 		new_matchlen = in6_matchlen(&ia->ia_addr.sin6_addr, &dst);
460 		if (best_matchlen < new_matchlen)
461 			REPLACE(14);
462 		if (new_matchlen < best_matchlen)
463 			NEXT(14);
464 
465 		/* Rule 15 is reserved. */
466 
467 		/*
468 		 * Last resort: just keep the current candidate.
469 		 * Or, do we need more rules?
470 		 */
471 		continue;
472 
473 	  replace:
474 		ia_best = ia;
475 		best_scope = (new_scope >= 0 ? new_scope :
476 			      in6_addrscope(&ia_best->ia_addr.sin6_addr));
477 		best_policy = (new_policy ? new_policy :
478 			       lookup_addrsel_policy(&ia_best->ia_addr));
479 		best_matchlen = (new_matchlen >= 0 ? new_matchlen :
480 				 in6_matchlen(&ia_best->ia_addr.sin6_addr,
481 					      &dst));
482 
483 	  next:
484 		continue;
485 
486 	  out:
487 		break;
488 	}
489 
490 	if ((ia = ia_best) == NULL) {
491 		IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
492 		IP6STAT_INC(ip6s_sources_none);
493 		return (EADDRNOTAVAIL);
494 	}
495 
496 	/*
497 	 * At this point at least one of the addresses belonged to the jail
498 	 * but it could still be, that we want to further restrict it, e.g.
499 	 * theoratically IN6_IS_ADDR_LOOPBACK.
500 	 * It must not be IN6_IS_ADDR_UNSPECIFIED anymore.
501 	 * prison_local_ip6() will fix an IN6_IS_ADDR_LOOPBACK but should
502 	 * let all others previously selected pass.
503 	 * Use tmp to not change ::1 on lo0 to the primary jail address.
504 	 */
505 	tmp = ia->ia_addr.sin6_addr;
506 	if (cred != NULL && prison_local_ip6(cred, &tmp, (inp != NULL &&
507 	    (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)) != 0) {
508 		IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
509 		IP6STAT_INC(ip6s_sources_none);
510 		return (EADDRNOTAVAIL);
511 	}
512 
513 	if (ifpp)
514 		*ifpp = ifp;
515 
516 	bcopy(&tmp, srcp, sizeof(*srcp));
517 	if (ia->ia_ifp == ifp)
518 		IP6STAT_INC2(ip6s_sources_sameif, best_scope);
519 	else
520 		IP6STAT_INC2(ip6s_sources_otherif, best_scope);
521 	if (dst_scope == best_scope)
522 		IP6STAT_INC2(ip6s_sources_samescope, best_scope);
523 	else
524 		IP6STAT_INC2(ip6s_sources_otherscope, best_scope);
525 	if (IFA6_IS_DEPRECATED(ia))
526 		IP6STAT_INC2(ip6s_sources_deprecated, best_scope);
527 	IN6_IFADDR_RUNLOCK(&in6_ifa_tracker);
528 	return (0);
529 }
530 
531 /*
532  * Select source address based on @inp, @dstsock and @opts.
533  * Stores selected address to @srcp. If @scope_ambiguous is set,
534  * embed scope from selected outgoing interface. If @hlim pointer
535  * is provided, stores calculated hop limit there.
536  * Returns 0 on success.
537  */
538 int
in6_selectsrc_socket(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct inpcb * inp,struct ucred * cred,int scope_ambiguous,struct in6_addr * srcp,int * hlim)539 in6_selectsrc_socket(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
540     struct inpcb *inp, struct ucred *cred, int scope_ambiguous,
541     struct in6_addr *srcp, int *hlim)
542 {
543 	struct ifnet *retifp;
544 	uint32_t fibnum;
545 	int error;
546 
547 	INP_LOCK_ASSERT(inp);
548 
549 	fibnum = inp->inp_inc.inc_fibnum;
550 	retifp = NULL;
551 
552 	error = in6_selectsrc(fibnum, dstsock, opts, inp->in6p_moptions,
553 	    inp, cred, &retifp, srcp);
554 	if (error != 0)
555 		return (error);
556 
557 	if (hlim != NULL)
558 		*hlim = in6_selecthlim(inp, retifp);
559 
560 	if (retifp == NULL || scope_ambiguous == 0)
561 		return (0);
562 
563 	/*
564 	 * Application should provide a proper zone ID or the use of
565 	 * default zone IDs should be enabled.  Unfortunately, some
566 	 * applications do not behave as it should, so we need a
567 	 * workaround.  Even if an appropriate ID is not determined
568 	 * (when it's required), if we can determine the outgoing
569 	 * interface. determine the zone ID based on the interface.
570 	 */
571 	error = in6_setscope(&dstsock->sin6_addr, retifp, NULL);
572 
573 	return (error);
574 }
575 
576 /*
577  * Select source address based on @fibnum, @dst and @scopeid.
578  * Stores selected address to @srcp.
579  * Returns 0 on success.
580  *
581  * Used by non-socket based consumers
582  */
583 int
in6_selectsrc_addr(uint32_t fibnum,const struct in6_addr * dst,uint32_t scopeid,struct ifnet * ifp,struct in6_addr * srcp,int * hlim)584 in6_selectsrc_addr(uint32_t fibnum, const struct in6_addr *dst,
585     uint32_t scopeid, struct ifnet *ifp, struct in6_addr *srcp,
586     int *hlim)
587 {
588 	struct ifnet *retifp;
589 	struct sockaddr_in6 dst_sa;
590 	int error;
591 
592 	retifp = ifp;
593 	bzero(&dst_sa, sizeof(dst_sa));
594 	dst_sa.sin6_family = AF_INET6;
595 	dst_sa.sin6_len = sizeof(dst_sa);
596 	dst_sa.sin6_addr = *dst;
597 	dst_sa.sin6_scope_id = scopeid;
598 	sa6_embedscope(&dst_sa, 0);
599 
600 	error = in6_selectsrc(fibnum, &dst_sa, NULL, NULL,
601 	    NULL, NULL, &retifp, srcp);
602 	if (hlim != NULL)
603 		*hlim = in6_selecthlim(NULL, retifp);
604 
605 	return (error);
606 }
607 
608 /*
609  * Select source address based on @fibnum, @dst and @mopts.
610  * Stores selected address to @srcp.
611  * Returns 0 on success.
612  *
613  * Used by non-socket based consumers (ND code mostly)
614  */
615 int
in6_selectsrc_nbr(uint32_t fibnum,const struct in6_addr * dst,struct ip6_moptions * mopts,struct ifnet * ifp,struct in6_addr * srcp)616 in6_selectsrc_nbr(uint32_t fibnum, const struct in6_addr *dst,
617     struct ip6_moptions *mopts, struct ifnet *ifp, struct in6_addr *srcp)
618 {
619 	struct sockaddr_in6 dst_sa;
620 	struct ifnet *retifp;
621 	int error;
622 
623 	retifp = ifp;
624 	bzero(&dst_sa, sizeof(dst_sa));
625 	dst_sa.sin6_family = AF_INET6;
626 	dst_sa.sin6_len = sizeof(dst_sa);
627 	dst_sa.sin6_addr = *dst;
628 	dst_sa.sin6_scope_id = ntohs(in6_getscope(dst));
629 	sa6_embedscope(&dst_sa, 0);
630 
631 	error = in6_selectsrc(fibnum, &dst_sa, NULL, mopts,
632 	    NULL, NULL, &retifp, srcp);
633 	return (error);
634 }
635 
636 static struct nhop_object *
cache_route(uint32_t fibnum,const struct sockaddr_in6 * dst,struct route_in6 * ro,uint32_t flowid)637 cache_route(uint32_t fibnum, const struct sockaddr_in6 *dst, struct route_in6 *ro,
638     uint32_t flowid)
639 {
640 	/*
641 	 * Use a cached route if it exists and is valid, else try to allocate
642 	 * a new one. Note that we should check the address family of the
643 	 * cached destination, in case of sharing the cache with IPv4.
644 	 * Assumes that 'struct route_in6' is exclusively locked.
645 	 */
646 	if (ro->ro_nh != NULL && (
647 	    !NH_IS_VALID(ro->ro_nh) || ro->ro_dst.sin6_family != AF_INET6 ||
648 	    !IN6_ARE_ADDR_EQUAL(&ro->ro_dst.sin6_addr, &dst->sin6_addr)))
649 		RO_NHFREE(ro);
650 
651 	if (ro->ro_nh == NULL) {
652 		ro->ro_dst = *dst;
653 
654 		const struct in6_addr *paddr;
655 		struct in6_addr unscoped_addr;
656 		uint32_t scopeid = 0;
657 		if (IN6_IS_SCOPE_LINKLOCAL(&dst->sin6_addr)) {
658 			in6_splitscope(&dst->sin6_addr, &unscoped_addr, &scopeid);
659 			paddr = &unscoped_addr;
660 		} else
661 			paddr = &dst->sin6_addr;
662 		ro->ro_nh = fib6_lookup(fibnum, paddr, scopeid, NHR_REF, flowid);
663 	}
664 	return (ro->ro_nh);
665 }
666 
667 static struct nhop_object *
lookup_route(uint32_t fibnum,struct sockaddr_in6 * dst,struct route_in6 * ro,struct ip6_pktopts * opts,uint32_t flowid)668 lookup_route(uint32_t fibnum, struct sockaddr_in6 *dst, struct route_in6 *ro,
669     struct ip6_pktopts *opts, uint32_t flowid)
670 {
671 	struct nhop_object *nh = NULL;
672 
673 	/*
674 	 * If the next hop address for the packet is specified by the caller,
675 	 * use it as the gateway.
676 	 */
677 	if (opts && opts->ip6po_nexthop) {
678 		struct route_in6 *ron = &opts->ip6po_nextroute;
679 		struct sockaddr_in6 *sin6_next = satosin6(opts->ip6po_nexthop);
680 
681 		nh = cache_route(fibnum, sin6_next, ron, flowid);
682 
683 		/*
684 		 * The node identified by that address must be a
685 		 * neighbor of the sending host.
686 		 */
687 		if (nh != NULL && (nh->nh_flags & NHF_GATEWAY) != 0)
688 			nh = NULL;
689 	} else if (ro != NULL) {
690 		nh = cache_route(fibnum, dst, ro, flowid);
691 		if (nh == NULL)
692 			return (NULL);
693 
694 		/*
695 		 * Check if the outgoing interface conflicts with
696 		 * the interface specified by ipi6_ifindex (if specified).
697 		 */
698 		struct in6_pktinfo *pi;
699 		if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
700 			if (nh->nh_aifp->if_index != pi->ipi6_ifindex)
701 				nh = NULL;
702 		}
703 	}
704 
705 	return (nh);
706 }
707 
708 /*
709  * Finds outgoing nexthop or the outgoing interface for the
710  * @dstsock.
711  * Return 0 on success and stores the lookup result in @retnh and @retifp
712  */
713 static int
selectroute(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct route_in6 * ro,struct ifnet ** retifp,struct nhop_object ** retnh,int norouteok,u_int fibnum,uint32_t flowid)714 selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
715     struct ip6_moptions *mopts, struct route_in6 *ro,
716     struct ifnet **retifp, struct nhop_object **retnh, int norouteok,
717     u_int fibnum, uint32_t flowid)
718 {
719 	int error = 0;
720 	struct ifnet *ifp = NULL;
721 	struct in6_pktinfo *pi = NULL;
722 	struct in6_addr *dst = &dstsock->sin6_addr;
723 
724 	/* If the caller specify the outgoing interface explicitly, use it. */
725 	if (opts && (pi = opts->ip6po_pktinfo) != NULL && pi->ipi6_ifindex) {
726 		/* XXX boundary check is assumed to be already done. */
727 		ifp = ifnet_byindex(pi->ipi6_ifindex);
728 		if (ifp != NULL && (norouteok || IN6_IS_ADDR_MULTICAST(dst))) {
729 			/*
730 			 * we do not have to check or get the route for
731 			 * multicast.
732 			 */
733 			goto done;
734 		} else
735 			goto getroute;
736 	}
737 	/*
738 	 * If the destination address is a multicast address and the outgoing
739 	 * interface for the address is specified by the caller, use it.
740 	 */
741 	if (IN6_IS_ADDR_MULTICAST(dst) &&
742 	    mopts != NULL && (ifp = mopts->im6o_multicast_ifp) != NULL) {
743 		goto done; /* we do not need a route for multicast. */
744 	}
745 	/*
746 	 * If destination address is LLA or link- or node-local multicast,
747 	 * use it's embedded scope zone id to determine outgoing interface.
748 	 */
749 	if (IN6_IS_ADDR_MC_LINKLOCAL(dst) ||
750 	    IN6_IS_ADDR_MC_NODELOCAL(dst)) {
751 		uint32_t zoneid = ntohs(in6_getscope(dst));
752 		if (zoneid > 0) {
753 			ifp = in6_getlinkifnet(zoneid);
754 			goto done;
755 		}
756 	}
757 
758   getroute:;
759 	struct nhop_object *nh = lookup_route(fibnum, dstsock, ro, opts, flowid);
760 	if (nh != NULL) {
761 		*retifp = nh->nh_aifp;
762 		error = 0;
763 	} else {
764 		*retifp = NULL;
765 		IP6STAT_INC(ip6s_noroute);
766 		error = EHOSTUNREACH;
767 	}
768 	*retnh = nh;
769 	return (error);
770 
771   done:
772 	if (ifp == NULL) {
773 		/*
774 		 * This can happen if the caller did not pass a cached route
775 		 * nor any other hints.  We treat this case an error.
776 		 */
777 		error = EHOSTUNREACH;
778 	}
779 	if (error == EHOSTUNREACH)
780 		IP6STAT_INC(ip6s_noroute);
781 
782 	*retifp = ifp;
783 	*retnh = NULL;
784 
785 	return (error);
786 }
787 
788 static int
in6_selectif(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct ifnet ** retifp,struct ifnet * oifp,u_int fibnum)789 in6_selectif(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
790     struct ip6_moptions *mopts, struct ifnet **retifp,
791     struct ifnet *oifp, u_int fibnum)
792 {
793 	int error;
794 	struct route_in6 sro;
795 	struct nhop_object *nh = NULL;
796 	uint16_t nh_flags;
797 
798 	KASSERT(retifp != NULL, ("%s: retifp is NULL", __func__));
799 
800 	bzero(&sro, sizeof(sro));
801 	nh_flags = 0;
802 
803 	error = selectroute(dstsock, opts, mopts, &sro, retifp, &nh, 1, fibnum, 0);
804 
805 	if (nh != NULL)
806 		nh_flags = nh->nh_flags;
807 	if (nh != NULL && nh == sro.ro_nh)
808 		NH_FREE(nh);
809 
810 	if (error != 0) {
811 		/* Help ND. See oifp comment in in6_selectsrc(). */
812 		if (oifp != NULL && fibnum == RT_DEFAULT_FIB) {
813 			*retifp = oifp;
814 			error = 0;
815 		}
816 		return (error);
817 	}
818 
819 	/*
820 	 * do not use a rejected or black hole route.
821 	 * XXX: this check should be done in the L2 output routine.
822 	 * However, if we skipped this check here, we'd see the following
823 	 * scenario:
824 	 * - install a rejected route for a scoped address prefix
825 	 *   (like fe80::/10)
826 	 * - send a packet to a destination that matches the scoped prefix,
827 	 *   with ambiguity about the scope zone.
828 	 * - pick the outgoing interface from the route, and disambiguate the
829 	 *   scope zone with the interface.
830 	 * - ip6_output() would try to get another route with the "new"
831 	 *   destination, which may be valid.
832 	 * - we'd see no error on output.
833 	 * Although this may not be very harmful, it should still be confusing.
834 	 * We thus reject the case here.
835 	 */
836 
837 	if (nh_flags & (NHF_REJECT | NHF_BLACKHOLE)) {
838 		error = (nh_flags & NHF_HOST ? EHOSTUNREACH : ENETUNREACH);
839 		return (error);
840 	}
841 
842 	return (0);
843 }
844 
845 /* Public wrapper function to selectroute(). */
846 int
in6_selectroute(struct sockaddr_in6 * dstsock,struct ip6_pktopts * opts,struct ip6_moptions * mopts,struct route_in6 * ro,struct ifnet ** retifp,struct nhop_object ** retnh,u_int fibnum,uint32_t flowid)847 in6_selectroute(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
848     struct ip6_moptions *mopts, struct route_in6 *ro,
849     struct ifnet **retifp, struct nhop_object **retnh, u_int fibnum, uint32_t flowid)
850 {
851 	MPASS(retifp != NULL);
852 	MPASS(retnh != NULL);
853 
854 	return (selectroute(dstsock, opts, mopts, ro, retifp,
855 	    retnh, 0, fibnum, flowid));
856 }
857 
858 /*
859  * Default hop limit selection. The precedence is as follows:
860  * 1. Hoplimit value specified via ioctl.
861  * 2. (If the outgoing interface is detected) the current
862  *     hop limit of the interface specified by router advertisement.
863  * 3. The system default hoplimit.
864  */
865 int
in6_selecthlim(struct inpcb * inp,struct ifnet * ifp)866 in6_selecthlim(struct inpcb *inp, struct ifnet *ifp)
867 {
868 
869 	if (inp && inp->in6p_hops >= 0)
870 		return (inp->in6p_hops);
871 	else if (ifp)
872 		return (ND_IFINFO(ifp)->chlim);
873 	else if (inp && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
874 		struct nhop_object *nh;
875 		struct in6_addr dst;
876 		uint32_t fibnum, scopeid;
877 		int hlim;
878 
879 		fibnum = inp->inp_inc.inc_fibnum;
880 		in6_splitscope(&inp->in6p_faddr, &dst, &scopeid);
881 		nh = fib6_lookup(fibnum, &dst, scopeid, 0, 0);
882 		if (nh != NULL) {
883 			hlim = ND_IFINFO(nh->nh_ifp)->chlim;
884 			return (hlim);
885 		}
886 	}
887 	return (V_ip6_defhlim);
888 }
889 
890 void
addrsel_policy_init(void)891 addrsel_policy_init(void)
892 {
893 
894 	init_policy_queue();
895 
896 	/* initialize the "last resort" policy */
897 	bzero(&V_defaultaddrpolicy, sizeof(V_defaultaddrpolicy));
898 	V_defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
899 
900 	if (!IS_DEFAULT_VNET(curvnet))
901 		return;
902 
903 	ADDRSEL_LOCK_INIT();
904 	ADDRSEL_SXLOCK_INIT();
905 }
906 
907 static struct in6_addrpolicy *
lookup_addrsel_policy(struct sockaddr_in6 * key)908 lookup_addrsel_policy(struct sockaddr_in6 *key)
909 {
910 	struct in6_addrpolicy *match = NULL;
911 
912 	ADDRSEL_LOCK();
913 	match = match_addrsel_policy(key);
914 
915 	if (match == NULL)
916 		match = &V_defaultaddrpolicy;
917 	else
918 		match->use++;
919 	ADDRSEL_UNLOCK();
920 
921 	return (match);
922 }
923 
924 /*
925  * Subroutines to manage the address selection policy table via sysctl.
926  */
927 struct walkarg {
928 	struct sysctl_req *w_req;
929 };
930 
931 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
932 SYSCTL_DECL(_net_inet6_ip6);
933 static SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
934     CTLFLAG_RD | CTLFLAG_MPSAFE, in6_src_sysctl,
935     "");
936 
937 static int
in6_src_sysctl(SYSCTL_HANDLER_ARGS)938 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
939 {
940 	struct walkarg w;
941 
942 	if (req->newptr)
943 		return EPERM;
944 
945 	bzero(&w, sizeof(w));
946 	w.w_req = req;
947 
948 	return (walk_addrsel_policy(dump_addrsel_policyent, &w));
949 }
950 
951 int
in6_src_ioctl(u_long cmd,caddr_t data)952 in6_src_ioctl(u_long cmd, caddr_t data)
953 {
954 	struct in6_addrpolicy ent0;
955 
956 	if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
957 		return (EOPNOTSUPP); /* check for safety */
958 
959 	ent0 = *(struct in6_addrpolicy *)data;
960 
961 	if (ent0.label == ADDR_LABEL_NOTAPP)
962 		return (EINVAL);
963 	/* check if the prefix mask is consecutive. */
964 	if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
965 		return (EINVAL);
966 	/* clear trailing garbages (if any) of the prefix address. */
967 	IN6_MASK_ADDR(&ent0.addr.sin6_addr, &ent0.addrmask.sin6_addr);
968 	ent0.use = 0;
969 
970 	switch (cmd) {
971 	case SIOCAADDRCTL_POLICY:
972 		return (add_addrsel_policyent(&ent0));
973 	case SIOCDADDRCTL_POLICY:
974 		return (delete_addrsel_policyent(&ent0));
975 	}
976 
977 	return (0);		/* XXX: compromise compilers */
978 }
979 
980 /*
981  * The followings are implementation of the policy table using a
982  * simple tail queue.
983  * XXX such details should be hidden.
984  * XXX implementation using binary tree should be more efficient.
985  */
986 struct addrsel_policyent {
987 	TAILQ_ENTRY(addrsel_policyent) ape_entry;
988 	struct in6_addrpolicy ape_policy;
989 };
990 
991 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
992 
993 VNET_DEFINE_STATIC(struct addrsel_policyhead, addrsel_policytab);
994 #define	V_addrsel_policytab		VNET(addrsel_policytab)
995 
996 static void
init_policy_queue(void)997 init_policy_queue(void)
998 {
999 
1000 	TAILQ_INIT(&V_addrsel_policytab);
1001 }
1002 
1003 static int
add_addrsel_policyent(struct in6_addrpolicy * newpolicy)1004 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
1005 {
1006 	struct addrsel_policyent *new, *pol;
1007 
1008 	new = malloc(sizeof(*new), M_IFADDR,
1009 	       M_WAITOK);
1010 	ADDRSEL_XLOCK();
1011 	ADDRSEL_LOCK();
1012 
1013 	/* duplication check */
1014 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1015 		if (IN6_ARE_ADDR_EQUAL(&newpolicy->addr.sin6_addr,
1016 				       &pol->ape_policy.addr.sin6_addr) &&
1017 		    IN6_ARE_ADDR_EQUAL(&newpolicy->addrmask.sin6_addr,
1018 				       &pol->ape_policy.addrmask.sin6_addr)) {
1019 			ADDRSEL_UNLOCK();
1020 			ADDRSEL_XUNLOCK();
1021 			free(new, M_IFADDR);
1022 			return (EEXIST);	/* or override it? */
1023 		}
1024 	}
1025 
1026 	bzero(new, sizeof(*new));
1027 
1028 	/* XXX: should validate entry */
1029 	new->ape_policy = *newpolicy;
1030 
1031 	TAILQ_INSERT_TAIL(&V_addrsel_policytab, new, ape_entry);
1032 	ADDRSEL_UNLOCK();
1033 	ADDRSEL_XUNLOCK();
1034 
1035 	return (0);
1036 }
1037 
1038 static int
delete_addrsel_policyent(struct in6_addrpolicy * key)1039 delete_addrsel_policyent(struct in6_addrpolicy *key)
1040 {
1041 	struct addrsel_policyent *pol;
1042 
1043 	ADDRSEL_XLOCK();
1044 	ADDRSEL_LOCK();
1045 
1046 	/* search for the entry in the table */
1047 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1048 		if (IN6_ARE_ADDR_EQUAL(&key->addr.sin6_addr,
1049 		    &pol->ape_policy.addr.sin6_addr) &&
1050 		    IN6_ARE_ADDR_EQUAL(&key->addrmask.sin6_addr,
1051 		    &pol->ape_policy.addrmask.sin6_addr)) {
1052 			break;
1053 		}
1054 	}
1055 	if (pol == NULL) {
1056 		ADDRSEL_UNLOCK();
1057 		ADDRSEL_XUNLOCK();
1058 		return (ESRCH);
1059 	}
1060 
1061 	TAILQ_REMOVE(&V_addrsel_policytab, pol, ape_entry);
1062 	ADDRSEL_UNLOCK();
1063 	ADDRSEL_XUNLOCK();
1064 	free(pol, M_IFADDR);
1065 
1066 	return (0);
1067 }
1068 
1069 static int
walk_addrsel_policy(int (* callback)(struct in6_addrpolicy *,void *),void * w)1070 walk_addrsel_policy(int (*callback)(struct in6_addrpolicy *, void *), void *w)
1071 {
1072 	struct addrsel_policyent *pol;
1073 	int error = 0;
1074 
1075 	ADDRSEL_SLOCK();
1076 	TAILQ_FOREACH(pol, &V_addrsel_policytab, ape_entry) {
1077 		if ((error = (*callback)(&pol->ape_policy, w)) != 0) {
1078 			ADDRSEL_SUNLOCK();
1079 			return (error);
1080 		}
1081 	}
1082 	ADDRSEL_SUNLOCK();
1083 	return (error);
1084 }
1085 
1086 static int
dump_addrsel_policyent(struct in6_addrpolicy * pol,void * arg)1087 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
1088 {
1089 	int error = 0;
1090 	struct walkarg *w = arg;
1091 
1092 	error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
1093 
1094 	return (error);
1095 }
1096 
1097 static struct in6_addrpolicy *
match_addrsel_policy(struct sockaddr_in6 * key)1098 match_addrsel_policy(struct sockaddr_in6 *key)
1099 {
1100 	struct addrsel_policyent *pent;
1101 	struct in6_addrpolicy *bestpol = NULL, *pol;
1102 	int matchlen, bestmatchlen = -1;
1103 	u_char *mp, *ep, *k, *p, m;
1104 
1105 	TAILQ_FOREACH(pent, &V_addrsel_policytab, ape_entry) {
1106 		matchlen = 0;
1107 
1108 		pol = &pent->ape_policy;
1109 		mp = (u_char *)&pol->addrmask.sin6_addr;
1110 		ep = mp + 16;	/* XXX: scope field? */
1111 		k = (u_char *)&key->sin6_addr;
1112 		p = (u_char *)&pol->addr.sin6_addr;
1113 		for (; mp < ep && *mp; mp++, k++, p++) {
1114 			m = *mp;
1115 			if ((*k & m) != *p)
1116 				goto next; /* not match */
1117 			if (m == 0xff) /* short cut for a typical case */
1118 				matchlen += 8;
1119 			else {
1120 				while (m >= 0x80) {
1121 					matchlen++;
1122 					m <<= 1;
1123 				}
1124 			}
1125 		}
1126 
1127 		/* matched.  check if this is better than the current best. */
1128 		if (bestpol == NULL ||
1129 		    matchlen > bestmatchlen) {
1130 			bestpol = pol;
1131 			bestmatchlen = matchlen;
1132 		}
1133 
1134 	  next:
1135 		continue;
1136 	}
1137 
1138 	return (bestpol);
1139 }
1140