xref: /dragonfly/sys/netinet6/in6_src.c (revision 279dd846)
1 /*	$FreeBSD: src/sys/netinet6/in6_src.c,v 1.1.2.3 2002/02/26 18:02:06 ume Exp $	*/
2 /*	$KAME: in6_src.c,v 1.37 2001/03/29 05:34:31 itojun Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the project nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 /*
34  * Copyright (c) 1982, 1986, 1991, 1993
35  *	The Regents of the University of California.  All rights reserved.
36  *
37  * Redistribution and use in source and binary forms, with or without
38  * modification, are permitted provided that the following conditions
39  * are met:
40  * 1. Redistributions of source code must retain the above copyright
41  *    notice, this list of conditions and the following disclaimer.
42  * 2. Redistributions in binary form must reproduce the above copyright
43  *    notice, this list of conditions and the following disclaimer in the
44  *    documentation and/or other materials provided with the distribution.
45  * 3. Neither the name of the University nor the names of its contributors
46  *    may be used to endorse or promote products derived from this software
47  *    without specific prior written permission.
48  *
49  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
50  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
51  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
52  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
53  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
54  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
55  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59  * SUCH DAMAGE.
60  *
61  *	@(#)in_pcb.c	8.2 (Berkeley) 1/4/94
62  */
63 
64 #include "opt_inet.h"
65 #include "opt_inet6.h"
66 
67 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <sys/jail.h>
70 #include <sys/kernel.h>
71 #include <sys/malloc.h>
72 #include <sys/mbuf.h>
73 #include <sys/protosw.h>
74 #include <sys/socket.h>
75 #include <sys/socketvar.h>
76 #include <sys/sockio.h>
77 #include <sys/sysctl.h>
78 #include <sys/errno.h>
79 #include <sys/time.h>
80 #include <sys/proc.h>
81 #include <sys/priv.h>
82 
83 #include <net/if.h>
84 #include <net/route.h>
85 
86 #include <netinet/in.h>
87 #include <netinet/in_var.h>
88 #include <netinet/in_systm.h>
89 #include <netinet/ip.h>
90 #include <netinet/in_pcb.h>
91 #include <netinet6/in6_var.h>
92 #include <netinet/ip6.h>
93 #include <netinet6/in6_pcb.h>
94 #include <netinet6/ip6_var.h>
95 #include <netinet6/nd6.h>
96 #ifdef ENABLE_DEFAULT_SCOPE
97 #include <netinet6/scope6_var.h>
98 #endif
99 
100 #include <net/net_osdep.h>
101 
102 #define ADDR_LABEL_NOTAPP (-1)
103 struct in6_addrpolicy defaultaddrpolicy;
104 
105 static void	init_policy_queue(void);
106 static int	add_addrsel_policyent(struct in6_addrpolicy *);
107 static int	delete_addrsel_policyent(struct in6_addrpolicy *);
108 static int	walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *),
109 				    void *);
110 static int	dump_addrsel_policyent(struct in6_addrpolicy *, void *);
111 
112 
113 /*
114  * Return an IPv6 address, which is the most appropriate for a given
115  * destination and user specified options.
116  * If necessary, this function lookups the routing table and returns
117  * an entry to the caller for later use.
118  */
119 struct in6_addr *
120 in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
121 	      struct ip6_moptions *mopts, struct route_in6 *ro,
122 	      struct in6_addr *laddr, int *errorp, struct thread *td)
123 {
124 	struct sockaddr_in6 jsin6;
125 	struct ucred *cred = NULL;
126 	struct in6_addr *dst;
127 	struct in6_ifaddr *ia6 = NULL;
128 	struct in6_pktinfo *pi = NULL;
129 	int jailed = 0;
130 
131 	if (td && td->td_proc && td->td_proc->p_ucred)
132 		cred = td->td_proc->p_ucred;
133 	if (cred && cred->cr_prison)
134 		jailed = 1;
135 	jsin6.sin6_family = AF_INET6;
136 	dst = &dstsock->sin6_addr;
137 	*errorp = 0;
138 
139 	/*
140 	 * If the source address is explicitly specified by the caller,
141 	 * use it.
142 	 */
143 	if (opts && (pi = opts->ip6po_pktinfo) &&
144 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
145 		jsin6.sin6_addr = pi->ipi6_addr;
146 		if (jailed && !jailed_ip(cred->cr_prison,
147 		    (struct sockaddr *)&jsin6)) {
148 			return(0);
149 		} else {
150 			return (&pi->ipi6_addr);
151 		}
152 	}
153 
154 	/*
155 	 * If the source address is not specified but the socket(if any)
156 	 * is already bound, use the bound address.
157 	 */
158 	if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
159 		jsin6.sin6_addr = *laddr;
160 		if (jailed && !jailed_ip(cred->cr_prison,
161 		    (struct sockaddr *)&jsin6)) {
162 			return(0);
163 		} else {
164 			return (laddr);
165 		}
166 	}
167 
168 	/*
169 	 * If the caller doesn't specify the source address but
170 	 * the outgoing interface, use an address associated with
171 	 * the interface.
172 	 */
173 	if (pi && pi->ipi6_ifindex) {
174 		/* XXX boundary check is assumed to be already done. */
175 		ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
176 				       dst, cred);
177 
178 		if (ia6 && jailed) {
179 			jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
180 			if (!jailed_ip(cred->cr_prison,
181 				(struct sockaddr *)&jsin6))
182 				ia6 = NULL;
183 		}
184 
185 		if (ia6 == NULL) {
186 			*errorp = EADDRNOTAVAIL;
187 			return (0);
188 		}
189 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
190 	}
191 
192 	/*
193 	 * If the destination address is a link-local unicast address or
194 	 * a multicast address, and if the outgoing interface is specified
195 	 * by the sin6_scope_id filed, use an address associated with the
196 	 * interface.
197 	 * XXX: We're now trying to define more specific semantics of
198 	 *      sin6_scope_id field, so this part will be rewritten in
199 	 *      the near future.
200 	 */
201 	if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) &&
202 	    dstsock->sin6_scope_id) {
203 		/*
204 		 * I'm not sure if boundary check for scope_id is done
205 		 * somewhere...
206 		 */
207 		if (dstsock->sin6_scope_id < 0 ||
208 		    if_index < dstsock->sin6_scope_id) {
209 			*errorp = ENXIO; /* XXX: better error? */
210 			return (0);
211 		}
212 		ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
213 				       dst, cred);
214 
215 		if (ia6 && jailed) {
216 			jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
217 			if (!jailed_ip(cred->cr_prison,
218 				(struct sockaddr *)&jsin6))
219 				ia6 = NULL;
220 		}
221 
222 		if (ia6 == NULL) {
223 			*errorp = EADDRNOTAVAIL;
224 			return (0);
225 		}
226 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
227 	}
228 
229 	/*
230 	 * If the destination address is a multicast address and
231 	 * the outgoing interface for the address is specified
232 	 * by the caller, use an address associated with the interface.
233 	 * There is a sanity check here; if the destination has node-local
234 	 * scope, the outgoing interfacde should be a loopback address.
235 	 * Even if the outgoing interface is not specified, we also
236 	 * choose a loopback interface as the outgoing interface.
237 	 */
238 	if (!jailed && IN6_IS_ADDR_MULTICAST(dst)) {
239 		struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
240 
241 		if (ifp == NULL && IN6_IS_ADDR_MC_INTFACELOCAL(dst)) {
242 			ifp = &loif[0];
243 		}
244 
245 		if (ifp) {
246 			ia6 = in6_ifawithscope(ifp, dst, cred);
247 			if (ia6 == NULL) {
248 				*errorp = EADDRNOTAVAIL;
249 				return (0);
250 			}
251 			return (&satosin6(&ia6->ia_addr)->sin6_addr);
252 		}
253 	}
254 
255 	/*
256 	 * If the next hop address for the packet is specified
257 	 * by caller, use an address associated with the route
258 	 * to the next hop.
259 	 */
260 	{
261 		struct sockaddr_in6 *sin6_next;
262 		struct rtentry *rt;
263 
264 		if (opts && opts->ip6po_nexthop) {
265 			sin6_next = satosin6(opts->ip6po_nexthop);
266 			rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL);
267 			if (rt) {
268 				ia6 = in6_ifawithscope(rt->rt_ifp, dst, cred);
269 				if (ia6 == NULL)
270 					ia6 = ifatoia6(rt->rt_ifa);
271 			}
272 			if (ia6 && jailed) {
273 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
274 				if (!jailed_ip(cred->cr_prison,
275 					(struct sockaddr *)&jsin6))
276 					ia6 = NULL;
277 			}
278 
279 			if (ia6 == NULL) {
280 				*errorp = EADDRNOTAVAIL;
281 				return (0);
282 			}
283 			return (&satosin6(&ia6->ia_addr)->sin6_addr);
284 		}
285 	}
286 
287 	/*
288 	 * If route is known or can be allocated now,
289 	 * our src addr is taken from the i/f, else punt.
290 	 */
291 	if (ro) {
292 		if (ro->ro_rt &&
293 		    (!(ro->ro_rt->rt_flags & RTF_UP) ||
294 		     satosin6(&ro->ro_dst)->sin6_family != AF_INET6 ||
295 		     !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
296 					 dst))) {
297 			RTFREE(ro->ro_rt);
298 			ro->ro_rt = NULL;
299 		}
300 		if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp == NULL) {
301 			struct sockaddr_in6 *sa6;
302 
303 			/* No route yet, so try to acquire one */
304 			bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
305 			sa6 = &ro->ro_dst;
306 			sa6->sin6_family = AF_INET6;
307 			sa6->sin6_len = sizeof(struct sockaddr_in6);
308 			sa6->sin6_addr = *dst;
309 			sa6->sin6_scope_id = dstsock->sin6_scope_id;
310 			if (!jailed && IN6_IS_ADDR_MULTICAST(dst)) {
311 				ro->ro_rt =
312 				  rtpurelookup((struct sockaddr *)&ro->ro_dst);
313 			} else {
314 				rtalloc((struct route *)ro);
315 			}
316 		}
317 
318 		/*
319 		 * in_pcbconnect() checks out IFF_LOOPBACK to skip using
320 		 * the address. But we don't know why it does so.
321 		 * It is necessary to ensure the scope even for lo0
322 		 * so doesn't check out IFF_LOOPBACK.
323 		 */
324 
325 		if (ro->ro_rt) {
326 			ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst, cred);
327 			if (ia6 && jailed) {
328 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
329 				if (!jailed_ip(cred->cr_prison,
330 					(struct sockaddr *)&jsin6))
331 					ia6 = NULL;
332 			}
333 
334 			if (ia6 == NULL) /* xxx scope error ?*/
335 				ia6 = ifatoia6(ro->ro_rt->rt_ifa);
336 
337 			if (ia6 && jailed) {
338 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
339 				if (!jailed_ip(cred->cr_prison,
340 					(struct sockaddr *)&jsin6))
341 					ia6 = NULL;
342 			}
343 		}
344 		if (ia6 == NULL) {
345 			*errorp = EHOSTUNREACH;	/* no route */
346 			return (0);
347 		}
348 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
349 	}
350 
351 	*errorp = EADDRNOTAVAIL;
352 	return (0);
353 }
354 
355 /*
356  * Default hop limit selection. The precedence is as follows:
357  * 1. Hoplimit value specified via ioctl.
358  * 2. (If the outgoing interface is detected) the current
359  *     hop limit of the interface specified by router advertisement.
360  * 3. The system default hoplimit.
361 */
362 int
363 in6_selecthlim(struct in6pcb *in6p, struct ifnet *ifp)
364 {
365 	int hlim;
366 
367 	if (in6p && in6p->in6p_hops >= 0) {
368 		return (in6p->in6p_hops);
369 	} else if (ifp) {
370 		hlim = ND_IFINFO(ifp)->chlim;
371 		if (hlim < ip6_minhlim)
372 			hlim = ip6_minhlim;
373 	} else {
374 		hlim = ip6_defhlim;
375 	}
376 	return (hlim);
377 }
378 
379 /*
380  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
381  * share this function by all *bsd*...
382  */
383 int
384 in6_pcbsetlport(struct in6_addr *laddr, struct inpcb *inp, struct thread *td)
385 {
386 	struct socket *so = inp->inp_socket;
387 	u_int16_t lport = 0, first, last, *lastport, step;
388 	int count, error = 0, wild = 0;
389 	struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
390 	struct inpcbportinfo *portinfo;
391 	struct ucred *cred = NULL;
392 	int portinfo_first, portinfo_idx;
393 
394 	/* XXX: this is redundant when called from in6_pcbbind */
395 	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
396 		wild = INPLOOKUP_WILDCARD;
397 	if (td->td_proc && td->td_proc->p_ucred)
398 		cred = td->td_proc->p_ucred;
399 
400 	inp->inp_flags |= INP_ANONPORT;
401 
402 	step = pcbinfo->portinfo_mask + 1;
403 	portinfo_first = mycpuid & pcbinfo->portinfo_mask;
404 	portinfo_idx = portinfo_first;
405 loop:
406 	portinfo = &pcbinfo->portinfo[portinfo_idx];
407 
408 	if (inp->inp_flags & INP_HIGHPORT) {
409 		first = ipport_hifirstauto;	/* sysctl */
410 		last  = ipport_hilastauto;
411 		lastport = &portinfo->lasthi;
412 	} else if (inp->inp_flags & INP_LOWPORT) {
413 		if ((error = priv_check(td, PRIV_ROOT)) != 0)
414 			return error;
415 		first = ipport_lowfirstauto;	/* 1023 */
416 		last  = ipport_lowlastauto;	/* 600 */
417 		lastport = &portinfo->lastlow;
418 	} else {
419 		first = ipport_firstauto;	/* sysctl */
420 		last  = ipport_lastauto;
421 		lastport = &portinfo->lastport;
422 	}
423 
424 	/*
425 	 * This has to be atomic.  If the porthash is shared across multiple
426 	 * protocol threads (aka tcp) then the token must be held.
427 	 */
428 	GET_PORT_TOKEN(portinfo);
429 
430 	/*
431 	 * Simple check to ensure all ports are not used up causing
432 	 * a deadlock here.
433 	 *
434 	 * We split the two cases (up and down) so that the direction
435 	 * is not being tested on each round of the loop.
436 	 */
437 	if (first > last) {
438 		/*
439 		 * counting down
440 		 */
441 		in_pcbportrange(&first, &last, portinfo->offset, step);
442 		count = (first - last) / step;
443 
444 		do {
445 			if (count-- < 0) {	/* completely used? */
446 				error = EAGAIN;
447 				goto done;
448 			}
449 			*lastport -= step;
450 			if (*lastport > first || *lastport < last)
451 				*lastport = first;
452 			KKASSERT((*lastport & pcbinfo->portinfo_mask) ==
453 			    portinfo->offset);
454 			lport = htons(*lastport);
455 		} while (in6_pcblookup_local(portinfo, &inp->in6p_laddr,
456 			 lport, wild, cred));
457 	} else {
458 		/*
459 		 * counting up
460 		 */
461 		in_pcbportrange(&last, &first, portinfo->offset, step);
462 		count = (last - first) / step;
463 
464 		do {
465 			if (count-- < 0) {	/* completely used? */
466 				error = EAGAIN;
467 				goto done;
468 			}
469 			*lastport += step;
470 			if (*lastport < first || *lastport > last)
471 				*lastport = first;
472 			KKASSERT((*lastport & pcbinfo->portinfo_mask) ==
473 			    portinfo->offset);
474 			lport = htons(*lastport);
475 		} while (in6_pcblookup_local(portinfo, &inp->in6p_laddr,
476 			 lport, wild, cred));
477 	}
478 
479 	inp->inp_lport = lport;
480 	in_pcbinsporthash(portinfo, inp);
481 	error = 0;
482 done:
483 	REL_PORT_TOKEN(portinfo);
484 
485 	if (error) {
486 		/* Try next portinfo */
487 		portinfo_idx++;
488 		portinfo_idx &= pcbinfo->portinfo_mask;
489 		if (portinfo_idx != portinfo_first)
490 			goto loop;
491 
492 		/* Undo any address bind that may have occurred above. */
493 		inp->in6p_laddr = kin6addr_any;
494 	}
495 	return error;
496 }
497 
498 /*
499  * Generate kernel-internal form (scopeid embedded into s6_addr16[1]).
500  * If the address scope of is link-local, embed the interface index in the
501  * address.  The routine determines our precedence
502  * between advanced API scope/interface specification and basic API
503  * specification.
504  *
505  * This function should be nuked in the future, when we get rid of embedded
506  * scopeid thing.
507  *
508  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
509  * there can be multiple interfaces that belong to a particular scope zone
510  * (in specification, we have 1:N mapping between a scope zone and interfaces).
511  * we may want to change the function to return something other than ifp.
512  */
513 int
514 in6_embedscope(struct in6_addr *in6,
515 	       const struct sockaddr_in6 *sin6,
516 #ifdef HAVE_NRL_INPCB
517 	       struct inpcb *in6p,
518 #define in6p_outputopts inp_outputopts6
519 #define in6p_moptions   inp_moptions6
520 #else
521 	       struct in6pcb *in6p,
522 #endif
523 	       struct ifnet **ifpp)
524 {
525 	struct ifnet *ifp = NULL;
526 	u_int32_t scopeid;
527 
528 	*in6 = sin6->sin6_addr;
529 	scopeid = sin6->sin6_scope_id;
530 	if (ifpp)
531 		*ifpp = NULL;
532 
533 	/*
534 	 * don't try to read sin6->sin6_addr beyond here, since the caller may
535 	 * ask us to overwrite existing sockaddr_in6
536 	 */
537 
538 #ifdef ENABLE_DEFAULT_SCOPE
539 	if (scopeid == 0)
540 		scopeid = scope6_addr2default(in6);
541 #endif
542 
543 	if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
544 		struct in6_pktinfo *pi;
545 
546 		/*
547 		 * KAME assumption: link id == interface id
548 		 */
549 
550 		if (in6p && in6p->in6p_outputopts &&
551 		    (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
552 		    pi->ipi6_ifindex) {
553 			ifp = ifindex2ifnet[pi->ipi6_ifindex];
554 			in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
555 		} else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
556 			   in6p->in6p_moptions &&
557 			   in6p->in6p_moptions->im6o_multicast_ifp) {
558 			ifp = in6p->in6p_moptions->im6o_multicast_ifp;
559 			in6->s6_addr16[1] = htons(ifp->if_index);
560 		} else if (scopeid) {
561 			/* boundary check */
562 			if (scopeid < 0 || if_index < scopeid)
563 				return ENXIO;  /* XXX EINVAL? */
564 			ifp = ifindex2ifnet[scopeid];
565 			/* XXX assignment to 16bit from 32bit variable */
566 			in6->s6_addr16[1] = htons(scopeid & 0xffff);
567 		}
568 
569 		if (ifpp)
570 			*ifpp = ifp;
571 	}
572 
573 	return 0;
574 }
575 #ifdef HAVE_NRL_INPCB
576 #undef in6p_outputopts
577 #undef in6p_moptions
578 #endif
579 
580 /*
581  * generate standard sockaddr_in6 from embedded form.
582  * touches sin6_addr and sin6_scope_id only.
583  *
584  * this function should be nuked in the future, when we get rid of
585  * embedded scopeid thing.
586  */
587 int
588 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6,
589 		 struct ifnet *ifp)
590 {
591 	u_int32_t zoneid;
592 
593 	sin6->sin6_addr = *in6;
594 
595 	/*
596 	 * don't try to read *in6 beyond here, since the caller may
597 	 * ask us to overwrite existing sockaddr_in6
598 	 */
599 
600 	sin6->sin6_scope_id = 0;
601 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
602 		/*
603 		 * KAME assumption: link id == interface id
604 		 */
605 		zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
606 		if (zoneid) {
607 			/* sanity check */
608 			if (zoneid < 0 || if_index < zoneid)
609 				return ENXIO;
610 			if (ifp && ifp->if_index != zoneid)
611 				return ENXIO;
612 			sin6->sin6_addr.s6_addr16[1] = 0;
613 			sin6->sin6_scope_id = zoneid;
614 		}
615 	}
616 
617 	return 0;
618 }
619 
620 /*
621  * just clear the embedded scope identifier.
622  */
623 void
624 in6_clearscope(struct in6_addr *addr)
625 {
626 	if (IN6_IS_SCOPE_LINKLOCAL(addr) || IN6_IS_ADDR_MC_INTFACELOCAL(addr))
627 		addr->s6_addr16[1] = 0;
628 }
629 
630 void
631 addrsel_policy_init(void)
632 {
633 
634 	init_policy_queue();
635 
636 	/* initialize the "last resort" policy */
637 	bzero(&defaultaddrpolicy, sizeof(defaultaddrpolicy));
638 	defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
639 }
640 
641 /*
642  * Subroutines to manage the address selection policy table via sysctl.
643  */
644 struct walkarg {
645 	struct sysctl_req *w_req;
646 };
647 
648 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
649 SYSCTL_DECL(_net_inet6_ip6);
650 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
651 	CTLFLAG_RD, in6_src_sysctl, "Address selection policy");
652 
653 static int
654 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
655 {
656 	struct walkarg w;
657 
658 	if (req->newptr)
659 		return EPERM;
660 
661 	bzero(&w, sizeof(w));
662 	w.w_req = req;
663 
664 	return (walk_addrsel_policy(dump_addrsel_policyent, &w));
665 }
666 
667 int
668 in6_src_ioctl(u_long cmd, caddr_t data)
669 {
670 	int i;
671 	struct in6_addrpolicy ent0;
672 
673 	if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
674 		return (EOPNOTSUPP); /* check for safety */
675 
676 	ent0 = *(struct in6_addrpolicy *)data;
677 
678 	if (ent0.label == ADDR_LABEL_NOTAPP)
679 		return (EINVAL);
680 	/* check if the prefix mask is consecutive. */
681 	if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
682 		return (EINVAL);
683 	/* clear trailing garbages (if any) of the prefix address. */
684 	for (i = 0; i < 4; i++) {
685 		ent0.addr.sin6_addr.s6_addr32[i] &=
686 			ent0.addrmask.sin6_addr.s6_addr32[i];
687 	}
688 	ent0.use = 0;
689 
690 	switch (cmd) {
691 	case SIOCAADDRCTL_POLICY:
692 		return (add_addrsel_policyent(&ent0));
693 	case SIOCDADDRCTL_POLICY:
694 		return (delete_addrsel_policyent(&ent0));
695 	}
696 
697 	return (0);		/* XXX: compromise compilers */
698 }
699 
700 /*
701  * The followings are implementation of the policy table using a
702  * simple tail queue.
703  * XXX such details should be hidden.
704  * XXX implementation using binary tree should be more efficient.
705  */
706 struct addrsel_policyent {
707 	TAILQ_ENTRY(addrsel_policyent) ape_entry;
708 	struct in6_addrpolicy ape_policy;
709 };
710 
711 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
712 
713 struct addrsel_policyhead addrsel_policytab;
714 
715 static void
716 init_policy_queue(void)
717 {
718 	TAILQ_INIT(&addrsel_policytab);
719 }
720 
721 static int
722 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
723 {
724 	struct addrsel_policyent *new, *pol;
725 
726 	/* duplication check */
727 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
728 	     pol = TAILQ_NEXT(pol, ape_entry)) {
729 		if (SA6_ARE_ADDR_EQUAL(&newpolicy->addr,
730 				       &pol->ape_policy.addr) &&
731 		    SA6_ARE_ADDR_EQUAL(&newpolicy->addrmask,
732 				       &pol->ape_policy.addrmask)) {
733 			return (EEXIST);	/* or override it? */
734 		}
735 	}
736 
737 	new = kmalloc(sizeof(*new), M_IFADDR, M_WAITOK | M_ZERO);
738 
739 	/* XXX: should validate entry */
740 	new->ape_policy = *newpolicy;
741 
742 	TAILQ_INSERT_TAIL(&addrsel_policytab, new, ape_entry);
743 
744 	return (0);
745 }
746 
747 static int
748 delete_addrsel_policyent(struct in6_addrpolicy *key)
749 {
750 	struct addrsel_policyent *pol;
751 
752 	/* search for the entry in the table */
753 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
754 	     pol = TAILQ_NEXT(pol, ape_entry)) {
755 		if (SA6_ARE_ADDR_EQUAL(&key->addr, &pol->ape_policy.addr) &&
756 		    SA6_ARE_ADDR_EQUAL(&key->addrmask,
757 				       &pol->ape_policy.addrmask)) {
758 			break;
759 		}
760 	}
761 	if (pol == NULL)
762 		return (ESRCH);
763 
764 	TAILQ_REMOVE(&addrsel_policytab, pol, ape_entry);
765 	kfree(pol, M_IFADDR);
766 
767 	return (0);
768 }
769 
770 static int
771 walk_addrsel_policy(int(*callback)(struct in6_addrpolicy *, void *), void *w)
772 {
773 	struct addrsel_policyent *pol;
774 	int error = 0;
775 
776 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
777 	     pol = TAILQ_NEXT(pol, ape_entry)) {
778 		if ((error = (*callback)(&pol->ape_policy, w)) != 0)
779 			return (error);
780 	}
781 
782 	return (error);
783 }
784 
785 static int
786 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
787 {
788 	int error = 0;
789 	struct walkarg *w = arg;
790 
791 	error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
792 
793 	return (error);
794 }
795