xref: /dragonfly/sys/netinet6/in6_src.c (revision a563ca70)
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. All advertising materials mentioning features or use of this software
46  *    must display the following acknowledgement:
47  *	This product includes software developed by the University of
48  *	California, Berkeley and its contributors.
49  * 4. Neither the name of the University nor the names of its contributors
50  *    may be used to endorse or promote products derived from this software
51  *    without specific prior written permission.
52  *
53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
63  * SUCH DAMAGE.
64  *
65  *	@(#)in_pcb.c	8.2 (Berkeley) 1/4/94
66  */
67 
68 #include "opt_inet.h"
69 #include "opt_inet6.h"
70 
71 #include <sys/param.h>
72 #include <sys/systm.h>
73 #include <sys/jail.h>
74 #include <sys/kernel.h>
75 #include <sys/malloc.h>
76 #include <sys/mbuf.h>
77 #include <sys/protosw.h>
78 #include <sys/socket.h>
79 #include <sys/socketvar.h>
80 #include <sys/sockio.h>
81 #include <sys/sysctl.h>
82 #include <sys/errno.h>
83 #include <sys/time.h>
84 #include <sys/proc.h>
85 #include <sys/priv.h>
86 
87 #include <net/if.h>
88 #include <net/route.h>
89 
90 #include <netinet/in.h>
91 #include <netinet/in_var.h>
92 #include <netinet/in_systm.h>
93 #include <netinet/ip.h>
94 #include <netinet/in_pcb.h>
95 #include <netinet6/in6_var.h>
96 #include <netinet/ip6.h>
97 #include <netinet6/in6_pcb.h>
98 #include <netinet6/ip6_var.h>
99 #include <netinet6/nd6.h>
100 #ifdef ENABLE_DEFAULT_SCOPE
101 #include <netinet6/scope6_var.h>
102 #endif
103 
104 #include <net/net_osdep.h>
105 
106 #define ADDR_LABEL_NOTAPP (-1)
107 struct in6_addrpolicy defaultaddrpolicy;
108 
109 static void	init_policy_queue(void);
110 static int	add_addrsel_policyent(struct in6_addrpolicy *);
111 static int	delete_addrsel_policyent(struct in6_addrpolicy *);
112 static int	walk_addrsel_policy(int (*)(struct in6_addrpolicy *, void *),
113 				    void *);
114 static int	dump_addrsel_policyent(struct in6_addrpolicy *, void *);
115 
116 
117 /*
118  * Return an IPv6 address, which is the most appropriate for a given
119  * destination and user specified options.
120  * If necessary, this function lookups the routing table and returns
121  * an entry to the caller for later use.
122  */
123 struct in6_addr *
124 in6_selectsrc(struct sockaddr_in6 *dstsock, struct ip6_pktopts *opts,
125 	      struct ip6_moptions *mopts, struct route_in6 *ro,
126 	      struct in6_addr *laddr, int *errorp, struct thread *td)
127 {
128 	struct sockaddr_in6 jsin6;
129 	struct ucred *cred = NULL;
130 	struct in6_addr *dst;
131 	struct in6_ifaddr *ia6 = 0;
132 	struct in6_pktinfo *pi = NULL;
133 	int jailed = 0;
134 
135 	if (td && td->td_proc && td->td_proc->p_ucred)
136 		cred = td->td_proc->p_ucred;
137 	if (cred && cred->cr_prison)
138 		jailed = 1;
139 	jsin6.sin6_family = AF_INET6;
140 	dst = &dstsock->sin6_addr;
141 	*errorp = 0;
142 
143 	/*
144 	 * If the source address is explicitly specified by the caller,
145 	 * use it.
146 	 */
147 	if (opts && (pi = opts->ip6po_pktinfo) &&
148 	    !IN6_IS_ADDR_UNSPECIFIED(&pi->ipi6_addr)) {
149 		jsin6.sin6_addr = pi->ipi6_addr;
150 		if (jailed && !jailed_ip(cred->cr_prison,
151 		    (struct sockaddr *)&jsin6)) {
152 			return(0);
153 		} else {
154 			return (&pi->ipi6_addr);
155 		}
156 	}
157 
158 	/*
159 	 * If the source address is not specified but the socket(if any)
160 	 * is already bound, use the bound address.
161 	 */
162 	if (laddr && !IN6_IS_ADDR_UNSPECIFIED(laddr)) {
163 		jsin6.sin6_addr = *laddr;
164 		if (jailed && !jailed_ip(cred->cr_prison,
165 		    (struct sockaddr *)&jsin6)) {
166 			return(0);
167 		} else {
168 			return (laddr);
169 		}
170 	}
171 
172 	/*
173 	 * If the caller doesn't specify the source address but
174 	 * the outgoing interface, use an address associated with
175 	 * the interface.
176 	 */
177 	if (pi && pi->ipi6_ifindex) {
178 		/* XXX boundary check is assumed to be already done. */
179 		ia6 = in6_ifawithscope(ifindex2ifnet[pi->ipi6_ifindex],
180 				       dst);
181 
182 		if (ia6 && jailed) {
183 			jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
184 			if (!jailed_ip(cred->cr_prison,
185 				(struct sockaddr *)&jsin6))
186 				ia6 = 0;
187 		}
188 
189 		if (ia6 == 0) {
190 			*errorp = EADDRNOTAVAIL;
191 			return (0);
192 		}
193 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
194 	}
195 
196 	/*
197 	 * If the destination address is a link-local unicast address or
198 	 * a multicast address, and if the outgoing interface is specified
199 	 * by the sin6_scope_id filed, use an address associated with the
200 	 * interface.
201 	 * XXX: We're now trying to define more specific semantics of
202 	 *      sin6_scope_id field, so this part will be rewritten in
203 	 *      the near future.
204 	 */
205 	if ((IN6_IS_ADDR_LINKLOCAL(dst) || IN6_IS_ADDR_MULTICAST(dst)) &&
206 	    dstsock->sin6_scope_id) {
207 		/*
208 		 * I'm not sure if boundary check for scope_id is done
209 		 * somewhere...
210 		 */
211 		if (dstsock->sin6_scope_id < 0 ||
212 		    if_index < dstsock->sin6_scope_id) {
213 			*errorp = ENXIO; /* XXX: better error? */
214 			return (0);
215 		}
216 		ia6 = in6_ifawithscope(ifindex2ifnet[dstsock->sin6_scope_id],
217 				       dst);
218 
219 		if (ia6 && jailed) {
220 			jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
221 			if (!jailed_ip(cred->cr_prison,
222 				(struct sockaddr *)&jsin6))
223 				ia6 = 0;
224 		}
225 
226 		if (ia6 == 0) {
227 			*errorp = EADDRNOTAVAIL;
228 			return (0);
229 		}
230 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
231 	}
232 
233 	/*
234 	 * If the destination address is a multicast address and
235 	 * the outgoing interface for the address is specified
236 	 * by the caller, use an address associated with the interface.
237 	 * There is a sanity check here; if the destination has node-local
238 	 * scope, the outgoing interfacde should be a loopback address.
239 	 * Even if the outgoing interface is not specified, we also
240 	 * choose a loopback interface as the outgoing interface.
241 	 */
242 	if (!jailed && IN6_IS_ADDR_MULTICAST(dst)) {
243 		struct ifnet *ifp = mopts ? mopts->im6o_multicast_ifp : NULL;
244 
245 		if (ifp == NULL && IN6_IS_ADDR_MC_NODELOCAL(dst)) {
246 			ifp = &loif[0];
247 		}
248 
249 		if (ifp) {
250 			ia6 = in6_ifawithscope(ifp, dst);
251 			if (ia6 == 0) {
252 				*errorp = EADDRNOTAVAIL;
253 				return (0);
254 			}
255 			return (&satosin6(&ia6->ia_addr)->sin6_addr);
256 		}
257 	}
258 
259 	/*
260 	 * If the next hop address for the packet is specified
261 	 * by caller, use an address associated with the route
262 	 * to the next hop.
263 	 */
264 	{
265 		struct sockaddr_in6 *sin6_next;
266 		struct rtentry *rt;
267 
268 		if (opts && opts->ip6po_nexthop) {
269 			sin6_next = satosin6(opts->ip6po_nexthop);
270 			rt = nd6_lookup(&sin6_next->sin6_addr, 1, NULL);
271 			if (rt) {
272 				ia6 = in6_ifawithscope(rt->rt_ifp, dst);
273 				if (ia6 == 0)
274 					ia6 = ifatoia6(rt->rt_ifa);
275 			}
276 			if (ia6 && jailed) {
277 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
278 				if (!jailed_ip(cred->cr_prison,
279 					(struct sockaddr *)&jsin6))
280 					ia6 = 0;
281 			}
282 
283 			if (ia6 == 0) {
284 				*errorp = EADDRNOTAVAIL;
285 				return (0);
286 			}
287 			return (&satosin6(&ia6->ia_addr)->sin6_addr);
288 		}
289 	}
290 
291 	/*
292 	 * If route is known or can be allocated now,
293 	 * our src addr is taken from the i/f, else punt.
294 	 */
295 	if (ro) {
296 		if (ro->ro_rt &&
297 		    (!(ro->ro_rt->rt_flags & RTF_UP) ||
298 		     satosin6(&ro->ro_dst)->sin6_family != AF_INET6 ||
299 		     !IN6_ARE_ADDR_EQUAL(&satosin6(&ro->ro_dst)->sin6_addr,
300 					 dst))) {
301 			RTFREE(ro->ro_rt);
302 			ro->ro_rt = NULL;
303 		}
304 		if (ro->ro_rt == NULL || ro->ro_rt->rt_ifp == NULL) {
305 			struct sockaddr_in6 *sa6;
306 
307 			/* No route yet, so try to acquire one */
308 			bzero(&ro->ro_dst, sizeof(struct sockaddr_in6));
309 			sa6 = &ro->ro_dst;
310 			sa6->sin6_family = AF_INET6;
311 			sa6->sin6_len = sizeof(struct sockaddr_in6);
312 			sa6->sin6_addr = *dst;
313 			sa6->sin6_scope_id = dstsock->sin6_scope_id;
314 			if (!jailed && IN6_IS_ADDR_MULTICAST(dst)) {
315 				ro->ro_rt =
316 				  rtpurelookup((struct sockaddr *)&ro->ro_dst);
317 			} else {
318 				rtalloc((struct route *)ro);
319 			}
320 		}
321 
322 		/*
323 		 * in_pcbconnect() checks out IFF_LOOPBACK to skip using
324 		 * the address. But we don't know why it does so.
325 		 * It is necessary to ensure the scope even for lo0
326 		 * so doesn't check out IFF_LOOPBACK.
327 		 */
328 
329 		if (ro->ro_rt) {
330 			ia6 = in6_ifawithscope(ro->ro_rt->rt_ifa->ifa_ifp, dst);
331 			if (ia6 && jailed) {
332 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
333 				if (!jailed_ip(cred->cr_prison,
334 					(struct sockaddr *)&jsin6))
335 					ia6 = 0;
336 			}
337 
338 			if (ia6 == 0) /* xxx scope error ?*/
339 				ia6 = ifatoia6(ro->ro_rt->rt_ifa);
340 
341 			if (ia6 && jailed) {
342 				jsin6.sin6_addr = (&ia6->ia_addr)->sin6_addr;
343 				if (!jailed_ip(cred->cr_prison,
344 					(struct sockaddr *)&jsin6))
345 					ia6 = 0;
346 			}
347 		}
348 #if 0
349 		/*
350 		 * xxx The followings are necessary? (kazu)
351 		 * I don't think so.
352 		 * It's for SO_DONTROUTE option in IPv4.(jinmei)
353 		 */
354 		if (ia6 == 0) {
355 			struct sockaddr_in6 sin6 = {sizeof(sin6), AF_INET6, 0};
356 
357 			sin6->sin6_addr = *dst;
358 
359 			ia6 = ifatoia6(ifa_ifwithdstaddr(sin6tosa(&sin6)));
360 			if (ia6 == 0)
361 				ia6 = ifatoia6(ifa_ifwithnet(sin6tosa(&sin6)));
362 			if (ia6 == 0)
363 				return (0);
364 			return (&satosin6(&ia6->ia_addr)->sin6_addr);
365 		}
366 #endif /* 0 */
367 		if (ia6 == 0) {
368 			*errorp = EHOSTUNREACH;	/* no route */
369 			return (0);
370 		}
371 		return (&satosin6(&ia6->ia_addr)->sin6_addr);
372 	}
373 
374 	*errorp = EADDRNOTAVAIL;
375 	return (0);
376 }
377 
378 /*
379  * Default hop limit selection. The precedence is as follows:
380  * 1. Hoplimit value specified via ioctl.
381  * 2. (If the outgoing interface is detected) the current
382  *     hop limit of the interface specified by router advertisement.
383  * 3. The system default hoplimit.
384 */
385 int
386 in6_selecthlim(struct in6pcb *in6p, struct ifnet *ifp)
387 {
388 	if (in6p && in6p->in6p_hops >= 0)
389 		return (in6p->in6p_hops);
390 	else if (ifp)
391 		return (ND_IFINFO(ifp)->chlim);
392 	else
393 		return (ip6_defhlim);
394 }
395 
396 /*
397  * XXX: this is borrowed from in6_pcbbind(). If possible, we should
398  * share this function by all *bsd*...
399  */
400 int
401 in6_pcbsetport(struct in6_addr *laddr, struct inpcb *inp, struct thread *td)
402 {
403 	struct socket *so = inp->inp_socket;
404 	u_int16_t lport = 0, first, last, *lastport;
405 	int count, error = 0, wild = 0;
406 	struct inpcbinfo *pcbinfo = inp->inp_pcbinfo;
407 	struct ucred *cred = NULL;
408 
409 	/* XXX: this is redundant when called from in6_pcbbind */
410 	if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0)
411 		wild = INPLOOKUP_WILDCARD;
412 	if (td->td_proc && td->td_proc->p_ucred)
413 		cred = td->td_proc->p_ucred;
414 
415 	inp->inp_flags |= INP_ANONPORT;
416 
417 	if (inp->inp_flags & INP_HIGHPORT) {
418 		first = ipport_hifirstauto;	/* sysctl */
419 		last  = ipport_hilastauto;
420 		lastport = &pcbinfo->lasthi;
421 	} else if (inp->inp_flags & INP_LOWPORT) {
422 		if ((error = priv_check(td, PRIV_ROOT)) != 0)
423 			return error;
424 		first = ipport_lowfirstauto;	/* 1023 */
425 		last  = ipport_lowlastauto;	/* 600 */
426 		lastport = &pcbinfo->lastlow;
427 	} else {
428 		first = ipport_firstauto;	/* sysctl */
429 		last  = ipport_lastauto;
430 		lastport = &pcbinfo->lastport;
431 	}
432 	/*
433 	 * Simple check to ensure all ports are not used up causing
434 	 * a deadlock here.
435 	 *
436 	 * We split the two cases (up and down) so that the direction
437 	 * is not being tested on each round of the loop.
438 	 */
439 	if (first > last) {
440 		/*
441 		 * counting down
442 		 */
443 		count = first - last;
444 
445 		do {
446 			if (count-- < 0) {	/* completely used? */
447 				/*
448 				 * Undo any address bind that may have
449 				 * occurred above.
450 				 */
451 				inp->in6p_laddr = kin6addr_any;
452 				return (EAGAIN);
453 			}
454 			--*lastport;
455 			if (*lastport > first || *lastport < last)
456 				*lastport = first;
457 			lport = htons(*lastport);
458 		} while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
459 			 lport, wild, cred));
460 	} else {
461 		/*
462 		 * counting up
463 		 */
464 		count = last - first;
465 
466 		do {
467 			if (count-- < 0) {	/* completely used? */
468 				/*
469 				 * Undo any address bind that may have
470 				 * occurred above.
471 				 */
472 				inp->in6p_laddr = kin6addr_any;
473 				return (EAGAIN);
474 			}
475 			++*lastport;
476 			if (*lastport < first || *lastport > last)
477 				*lastport = first;
478 			lport = htons(*lastport);
479 		} while (in6_pcblookup_local(pcbinfo, &inp->in6p_laddr,
480 			 lport, wild, cred));
481 	}
482 
483 	inp->inp_lport = lport;
484 	if (in_pcbinsporthash(inp) != 0) {
485 		inp->in6p_laddr = kin6addr_any;
486 		inp->inp_lport = 0;
487 		return (EAGAIN);
488 	}
489 
490 	return (0);
491 }
492 
493 /*
494  * generate kernel-internal form (scopeid embedded into s6_addr16[1]).
495  * If the address scope of is link-local, embed the interface index in the
496  * address.  The routine determines our precedence
497  * between advanced API scope/interface specification and basic API
498  * specification.
499  *
500  * this function should be nuked in the future, when we get rid of
501  * embedded scopeid thing.
502  *
503  * XXX actually, it is over-specification to return ifp against sin6_scope_id.
504  * there can be multiple interfaces that belong to a particular scope zone
505  * (in specification, we have 1:N mapping between a scope zone and interfaces).
506  * we may want to change the function to return something other than ifp.
507  */
508 int
509 in6_embedscope(struct in6_addr *in6,
510 	       const struct sockaddr_in6 *sin6,
511 #ifdef HAVE_NRL_INPCB
512 	       struct inpcb *in6p,
513 #define in6p_outputopts inp_outputopts6
514 #define in6p_moptions   inp_moptions6
515 #else
516 	       struct in6pcb *in6p,
517 #endif
518 	       struct ifnet **ifpp)
519 {
520 	struct ifnet *ifp = NULL;
521 	u_int32_t scopeid;
522 
523 	*in6 = sin6->sin6_addr;
524 	scopeid = sin6->sin6_scope_id;
525 	if (ifpp)
526 		*ifpp = NULL;
527 
528 	/*
529 	 * don't try to read sin6->sin6_addr beyond here, since the caller may
530 	 * ask us to overwrite existing sockaddr_in6
531 	 */
532 
533 #ifdef ENABLE_DEFAULT_SCOPE
534 	if (scopeid == 0)
535 		scopeid = scope6_addr2default(in6);
536 #endif
537 
538 	if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
539 		struct in6_pktinfo *pi;
540 
541 		/*
542 		 * KAME assumption: link id == interface id
543 		 */
544 
545 		if (in6p && in6p->in6p_outputopts &&
546 		    (pi = in6p->in6p_outputopts->ip6po_pktinfo) &&
547 		    pi->ipi6_ifindex) {
548 			ifp = ifindex2ifnet[pi->ipi6_ifindex];
549 			in6->s6_addr16[1] = htons(pi->ipi6_ifindex);
550 		} else if (in6p && IN6_IS_ADDR_MULTICAST(in6) &&
551 			   in6p->in6p_moptions &&
552 			   in6p->in6p_moptions->im6o_multicast_ifp) {
553 			ifp = in6p->in6p_moptions->im6o_multicast_ifp;
554 			in6->s6_addr16[1] = htons(ifp->if_index);
555 		} else if (scopeid) {
556 			/* boundary check */
557 			if (scopeid < 0 || if_index < scopeid)
558 				return ENXIO;  /* XXX EINVAL? */
559 			ifp = ifindex2ifnet[scopeid];
560 			/*XXX assignment to 16bit from 32bit variable */
561 			in6->s6_addr16[1] = htons(scopeid & 0xffff);
562 		}
563 
564 		if (ifpp)
565 			*ifpp = ifp;
566 	}
567 
568 	return 0;
569 }
570 #ifdef HAVE_NRL_INPCB
571 #undef in6p_outputopts
572 #undef in6p_moptions
573 #endif
574 
575 /*
576  * generate standard sockaddr_in6 from embedded form.
577  * touches sin6_addr and sin6_scope_id only.
578  *
579  * this function should be nuked in the future, when we get rid of
580  * embedded scopeid thing.
581  */
582 int
583 in6_recoverscope(struct sockaddr_in6 *sin6, const struct in6_addr *in6,
584 		 struct ifnet *ifp)
585 {
586 	u_int32_t scopeid;
587 
588 	sin6->sin6_addr = *in6;
589 
590 	/*
591 	 * don't try to read *in6 beyond here, since the caller may
592 	 * ask us to overwrite existing sockaddr_in6
593 	 */
594 
595 	sin6->sin6_scope_id = 0;
596 	if (IN6_IS_SCOPE_LINKLOCAL(in6)) {
597 		/*
598 		 * KAME assumption: link id == interface id
599 		 */
600 		scopeid = ntohs(sin6->sin6_addr.s6_addr16[1]);
601 		if (scopeid) {
602 			/* sanity check */
603 			if (scopeid < 0 || if_index < scopeid)
604 				return ENXIO;
605 			if (ifp && ifp->if_index != scopeid)
606 				return ENXIO;
607 			sin6->sin6_addr.s6_addr16[1] = 0;
608 			sin6->sin6_scope_id = scopeid;
609 		}
610 	}
611 
612 	return 0;
613 }
614 
615 /*
616  * just clear the embedded scope identifer.
617  * XXX: currently used for bsdi4 only as a supplement function.
618  */
619 void
620 in6_clearscope(struct in6_addr *addr)
621 {
622 	if (IN6_IS_SCOPE_LINKLOCAL(addr))
623 		addr->s6_addr16[1] = 0;
624 }
625 
626 void
627 addrsel_policy_init(void)
628 {
629 
630 	init_policy_queue();
631 
632 	/* initialize the "last resort" policy */
633 	bzero(&defaultaddrpolicy, sizeof(defaultaddrpolicy));
634 	defaultaddrpolicy.label = ADDR_LABEL_NOTAPP;
635 }
636 
637 /*
638  * Subroutines to manage the address selection policy table via sysctl.
639  */
640 struct walkarg {
641 	struct sysctl_req *w_req;
642 };
643 
644 static int in6_src_sysctl(SYSCTL_HANDLER_ARGS);
645 SYSCTL_DECL(_net_inet6_ip6);
646 SYSCTL_NODE(_net_inet6_ip6, IPV6CTL_ADDRCTLPOLICY, addrctlpolicy,
647 	CTLFLAG_RD, in6_src_sysctl, "Address selection policy");
648 
649 static int
650 in6_src_sysctl(SYSCTL_HANDLER_ARGS)
651 {
652 	struct walkarg w;
653 
654 	if (req->newptr)
655 		return EPERM;
656 
657 	bzero(&w, sizeof(w));
658 	w.w_req = req;
659 
660 	return (walk_addrsel_policy(dump_addrsel_policyent, &w));
661 }
662 
663 int
664 in6_src_ioctl(u_long cmd, caddr_t data)
665 {
666 	int i;
667 	struct in6_addrpolicy ent0;
668 
669 	if (cmd != SIOCAADDRCTL_POLICY && cmd != SIOCDADDRCTL_POLICY)
670 		return (EOPNOTSUPP); /* check for safety */
671 
672 	ent0 = *(struct in6_addrpolicy *)data;
673 
674 	if (ent0.label == ADDR_LABEL_NOTAPP)
675 		return (EINVAL);
676 	/* check if the prefix mask is consecutive. */
677 	if (in6_mask2len(&ent0.addrmask.sin6_addr, NULL) < 0)
678 		return (EINVAL);
679 	/* clear trailing garbages (if any) of the prefix address. */
680 	for (i = 0; i < 4; i++) {
681 		ent0.addr.sin6_addr.s6_addr32[i] &=
682 			ent0.addrmask.sin6_addr.s6_addr32[i];
683 	}
684 	ent0.use = 0;
685 
686 	switch (cmd) {
687 	case SIOCAADDRCTL_POLICY:
688 		return (add_addrsel_policyent(&ent0));
689 	case SIOCDADDRCTL_POLICY:
690 		return (delete_addrsel_policyent(&ent0));
691 	}
692 
693 	return (0);		/* XXX: compromise compilers */
694 }
695 
696 /*
697  * The followings are implementation of the policy table using a
698  * simple tail queue.
699  * XXX such details should be hidden.
700  * XXX implementation using binary tree should be more efficient.
701  */
702 struct addrsel_policyent {
703 	TAILQ_ENTRY(addrsel_policyent) ape_entry;
704 	struct in6_addrpolicy ape_policy;
705 };
706 
707 TAILQ_HEAD(addrsel_policyhead, addrsel_policyent);
708 
709 struct addrsel_policyhead addrsel_policytab;
710 
711 static void
712 init_policy_queue(void)
713 {
714 	TAILQ_INIT(&addrsel_policytab);
715 }
716 
717 static int
718 add_addrsel_policyent(struct in6_addrpolicy *newpolicy)
719 {
720 	struct addrsel_policyent *new, *pol;
721 
722 	/* duplication check */
723 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
724 	     pol = TAILQ_NEXT(pol, ape_entry)) {
725 		if (SA6_ARE_ADDR_EQUAL(&newpolicy->addr,
726 				       &pol->ape_policy.addr) &&
727 		    SA6_ARE_ADDR_EQUAL(&newpolicy->addrmask,
728 				       &pol->ape_policy.addrmask)) {
729 			return (EEXIST);	/* or override it? */
730 		}
731 	}
732 
733 	new = kmalloc(sizeof(*new), M_IFADDR, M_WAITOK | M_ZERO);
734 
735 	/* XXX: should validate entry */
736 	new->ape_policy = *newpolicy;
737 
738 	TAILQ_INSERT_TAIL(&addrsel_policytab, new, ape_entry);
739 
740 	return (0);
741 }
742 
743 static int
744 delete_addrsel_policyent(struct in6_addrpolicy *key)
745 {
746 	struct addrsel_policyent *pol;
747 
748 	/* search for the entry in the table */
749 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
750 	     pol = TAILQ_NEXT(pol, ape_entry)) {
751 		if (SA6_ARE_ADDR_EQUAL(&key->addr, &pol->ape_policy.addr) &&
752 		    SA6_ARE_ADDR_EQUAL(&key->addrmask,
753 				       &pol->ape_policy.addrmask)) {
754 			break;
755 		}
756 	}
757 	if (pol == NULL)
758 		return (ESRCH);
759 
760 	TAILQ_REMOVE(&addrsel_policytab, pol, ape_entry);
761 	kfree(pol, M_IFADDR);
762 
763 	return (0);
764 }
765 
766 static int
767 walk_addrsel_policy(int(*callback)(struct in6_addrpolicy *, void *), void *w)
768 {
769 	struct addrsel_policyent *pol;
770 	int error = 0;
771 
772 	for (pol = TAILQ_FIRST(&addrsel_policytab); pol;
773 	     pol = TAILQ_NEXT(pol, ape_entry)) {
774 		if ((error = (*callback)(&pol->ape_policy, w)) != 0)
775 			return (error);
776 	}
777 
778 	return (error);
779 }
780 
781 static int
782 dump_addrsel_policyent(struct in6_addrpolicy *pol, void *arg)
783 {
784 	int error = 0;
785 	struct walkarg *w = arg;
786 
787 	error = SYSCTL_OUT(w->w_req, pol, sizeof(*pol));
788 
789 	return (error);
790 }
791