xref: /freebsd/sys/netinet6/scope6.c (revision 63a938566d524836885917d95bd491aa4400b181)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 2000 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: scope6.c,v 1.10 2000/07/24 13:29:31 itojun Exp $
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/malloc.h>
39 #include <sys/mbuf.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/systm.h>
43 #include <sys/queue.h>
44 #include <sys/sysctl.h>
45 #include <sys/syslog.h>
46 
47 #include <net/if.h>
48 #include <net/if_var.h>
49 #include <net/vnet.h>
50 
51 #include <netinet/in.h>
52 
53 #include <netinet/ip6.h>
54 #include <netinet6/in6_var.h>
55 #include <netinet6/ip6_var.h>
56 #include <netinet6/scope6_var.h>
57 
58 #ifdef ENABLE_DEFAULT_SCOPE
59 VNET_DEFINE(int, ip6_use_defzone) = 1;
60 #else
61 VNET_DEFINE(int, ip6_use_defzone) = 0;
62 #endif
63 VNET_DEFINE(int, deembed_scopeid) = 1;
64 SYSCTL_DECL(_net_inet6_ip6);
65 SYSCTL_INT(_net_inet6_ip6, OID_AUTO, deembed_scopeid, CTLFLAG_VNET | CTLFLAG_RW,
66     &VNET_NAME(deembed_scopeid), 0,
67     "Extract embedded zone ID and set it to sin6_scope_id in sockaddr_in6.");
68 
69 /*
70  * The scope6_lock protects the global sid default stored in
71  * sid_default below.
72  */
73 static struct mtx scope6_lock;
74 #define	SCOPE6_LOCK_INIT()	mtx_init(&scope6_lock, "scope6_lock", NULL, MTX_DEF)
75 #define	SCOPE6_LOCK()		mtx_lock(&scope6_lock)
76 #define	SCOPE6_UNLOCK()		mtx_unlock(&scope6_lock)
77 #define	SCOPE6_LOCK_ASSERT()	mtx_assert(&scope6_lock, MA_OWNED)
78 
79 static VNET_DEFINE(struct scope6_id, sid_default);
80 #define	V_sid_default			VNET(sid_default)
81 
82 #define SID(ifp) \
83 	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
84 
85 static int	scope6_get(struct ifnet *, struct scope6_id *);
86 static int	scope6_set(struct ifnet *, struct scope6_id *);
87 
88 void
89 scope6_init(void)
90 {
91 
92 	bzero(&V_sid_default, sizeof(V_sid_default));
93 
94 	if (!IS_DEFAULT_VNET(curvnet))
95 		return;
96 
97 	SCOPE6_LOCK_INIT();
98 }
99 
100 struct scope6_id *
101 scope6_ifattach(struct ifnet *ifp)
102 {
103 	struct scope6_id *sid;
104 
105 	sid = malloc(sizeof(*sid), M_IFADDR, M_WAITOK | M_ZERO);
106 	/*
107 	 * XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
108 	 * Should we rather hardcode here?
109 	 */
110 	sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
111 	sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
112 	return (sid);
113 }
114 
115 void
116 scope6_ifdetach(struct scope6_id *sid)
117 {
118 
119 	free(sid, M_IFADDR);
120 }
121 
122 int
123 scope6_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp)
124 {
125 	struct in6_ifreq *ifr;
126 
127 	if (ifp->if_afdata[AF_INET6] == NULL)
128 		return (EPFNOSUPPORT);
129 
130 	ifr = (struct in6_ifreq *)data;
131 	switch (cmd) {
132 	case SIOCSSCOPE6:
133 		return (scope6_set(ifp,
134 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
135 	case SIOCGSCOPE6:
136 		return (scope6_get(ifp,
137 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
138 	case SIOCGSCOPE6DEF:
139 		return (scope6_get_default(
140 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
141 	default:
142 		return (EOPNOTSUPP);
143 	}
144 }
145 
146 static int
147 scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
148 {
149 	int i;
150 	int error = 0;
151 	struct scope6_id *sid = NULL;
152 
153 	IF_AFDATA_WLOCK(ifp);
154 	sid = SID(ifp);
155 
156 	if (!sid) {	/* paranoid? */
157 		IF_AFDATA_WUNLOCK(ifp);
158 		return (EINVAL);
159 	}
160 
161 	/*
162 	 * XXX: We need more consistency checks of the relationship among
163 	 * scopes (e.g. an organization should be larger than a site).
164 	 */
165 
166 	/*
167 	 * TODO(XXX): after setting, we should reflect the changes to
168 	 * interface addresses, routing table entries, PCB entries...
169 	 */
170 
171 	for (i = 0; i < 16; i++) {
172 		if (idlist->s6id_list[i] &&
173 		    idlist->s6id_list[i] != sid->s6id_list[i]) {
174 			/*
175 			 * An interface zone ID must be the corresponding
176 			 * interface index by definition.
177 			 */
178 			if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
179 			    idlist->s6id_list[i] != ifp->if_index) {
180 				IF_AFDATA_WUNLOCK(ifp);
181 				return (EINVAL);
182 			}
183 
184 			if (i == IPV6_ADDR_SCOPE_LINKLOCAL &&
185 			    idlist->s6id_list[i] > V_if_index) {
186 				/*
187 				 * XXX: theoretically, there should be no
188 				 * relationship between link IDs and interface
189 				 * IDs, but we check the consistency for
190 				 * safety in later use.
191 				 */
192 				IF_AFDATA_WUNLOCK(ifp);
193 				return (EINVAL);
194 			}
195 
196 			/*
197 			 * XXX: we must need lots of work in this case,
198 			 * but we simply set the new value in this initial
199 			 * implementation.
200 			 */
201 			sid->s6id_list[i] = idlist->s6id_list[i];
202 		}
203 	}
204 	IF_AFDATA_WUNLOCK(ifp);
205 
206 	return (error);
207 }
208 
209 static int
210 scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
211 {
212 	struct scope6_id *sid;
213 
214 	/* We only need to lock the interface's afdata for SID() to work. */
215 	IF_AFDATA_RLOCK(ifp);
216 	sid = SID(ifp);
217 	if (sid == NULL) {	/* paranoid? */
218 		IF_AFDATA_RUNLOCK(ifp);
219 		return (EINVAL);
220 	}
221 
222 	*idlist = *sid;
223 
224 	IF_AFDATA_RUNLOCK(ifp);
225 	return (0);
226 }
227 
228 /*
229  * Get a scope of the address. Node-local, link-local, site-local or global.
230  */
231 int
232 in6_addrscope(const struct in6_addr *addr)
233 {
234 
235 	if (IN6_IS_ADDR_MULTICAST(addr)) {
236 		/*
237 		 * Addresses with reserved value F must be treated as
238 		 * global multicast addresses.
239 		 */
240 		if (IPV6_ADDR_MC_SCOPE(addr) == 0x0f)
241 			return (IPV6_ADDR_SCOPE_GLOBAL);
242 		return (IPV6_ADDR_MC_SCOPE(addr));
243 	}
244 	if (IN6_IS_ADDR_LINKLOCAL(addr) ||
245 	    IN6_IS_ADDR_LOOPBACK(addr))
246 		return (IPV6_ADDR_SCOPE_LINKLOCAL);
247 	if (IN6_IS_ADDR_SITELOCAL(addr))
248 		return (IPV6_ADDR_SCOPE_SITELOCAL);
249 	return (IPV6_ADDR_SCOPE_GLOBAL);
250 }
251 
252 /*
253  * ifp - note that this might be NULL
254  */
255 
256 void
257 scope6_setdefault(struct ifnet *ifp)
258 {
259 
260 	/*
261 	 * Currently, this function just sets the default "interfaces"
262 	 * and "links" according to the given interface.
263 	 * We might eventually have to separate the notion of "link" from
264 	 * "interface" and provide a user interface to set the default.
265 	 */
266 	SCOPE6_LOCK();
267 	if (ifp) {
268 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
269 			ifp->if_index;
270 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
271 			ifp->if_index;
272 	} else {
273 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
274 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
275 	}
276 	SCOPE6_UNLOCK();
277 }
278 
279 int
280 scope6_get_default(struct scope6_id *idlist)
281 {
282 
283 	SCOPE6_LOCK();
284 	*idlist = V_sid_default;
285 	SCOPE6_UNLOCK();
286 
287 	return (0);
288 }
289 
290 u_int32_t
291 scope6_addr2default(struct in6_addr *addr)
292 {
293 	u_int32_t id;
294 
295 	/*
296 	 * special case: The loopback address should be considered as
297 	 * link-local, but there's no ambiguity in the syntax.
298 	 */
299 	if (IN6_IS_ADDR_LOOPBACK(addr))
300 		return (0);
301 
302 	/*
303 	 * XXX: 32-bit read is atomic on all our platforms, is it OK
304 	 * not to lock here?
305 	 */
306 	SCOPE6_LOCK();
307 	id = V_sid_default.s6id_list[in6_addrscope(addr)];
308 	SCOPE6_UNLOCK();
309 	return (id);
310 }
311 
312 /*
313  * Validate the specified scope zone ID in the sin6_scope_id field.  If the ID
314  * is unspecified (=0), needs to be specified, and the default zone ID can be
315  * used, the default value will be used.
316  * This routine then generates the kernel-internal form: if the address scope
317  * of is interface-local or link-local, embed the interface index in the
318  * address.
319  */
320 int
321 sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
322 {
323 	u_int32_t zoneid;
324 
325 	if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
326 		zoneid = scope6_addr2default(&sin6->sin6_addr);
327 
328 	if (zoneid != 0 &&
329 	    (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
330 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
331 		/*
332 		 * At this moment, we only check interface-local and
333 		 * link-local scope IDs, and use interface indices as the
334 		 * zone IDs assuming a one-to-one mapping between interfaces
335 		 * and links.
336 		 */
337 		if (V_if_index < zoneid || ifnet_byindex(zoneid) == NULL)
338 			return (ENXIO);
339 
340 		/* XXX assignment to 16bit from 32bit variable */
341 		sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
342 		sin6->sin6_scope_id = 0;
343 	}
344 
345 	return 0;
346 }
347 
348 /*
349  * generate standard sockaddr_in6 from embedded form.
350  */
351 int
352 sa6_recoverscope(struct sockaddr_in6 *sin6)
353 {
354 	char ip6buf[INET6_ADDRSTRLEN];
355 	u_int32_t zoneid;
356 
357 	if (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
358 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr)) {
359 		/*
360 		 * KAME assumption: link id == interface id
361 		 */
362 		zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
363 		if (zoneid) {
364 			/* sanity check */
365 			if (V_if_index < zoneid)
366 				return (ENXIO);
367 #if 0
368 			/* XXX: Disabled due to possible deadlock. */
369 			if (!ifnet_byindex(zoneid))
370 				return (ENXIO);
371 #endif
372 			if (sin6->sin6_scope_id != 0 &&
373 			    zoneid != sin6->sin6_scope_id) {
374 				log(LOG_NOTICE,
375 				    "%s: embedded scope mismatch: %s%%%d. "
376 				    "sin6_scope_id was overridden\n", __func__,
377 				    ip6_sprintf(ip6buf, &sin6->sin6_addr),
378 				    sin6->sin6_scope_id);
379 			}
380 			sin6->sin6_addr.s6_addr16[1] = 0;
381 			sin6->sin6_scope_id = zoneid;
382 		}
383 	}
384 
385 	return 0;
386 }
387 
388 /*
389  * Determine the appropriate scope zone ID for in6 and ifp.  If ret_id is
390  * non NULL, it is set to the zone ID.  If the zone ID needs to be embedded
391  * in the in6_addr structure, in6 will be modified.
392  *
393  * ret_id - unnecessary?
394  */
395 int
396 in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
397 {
398 	int scope;
399 	u_int32_t zoneid = 0;
400 	struct scope6_id *sid;
401 
402 	/*
403 	 * special case: the loopback address can only belong to a loopback
404 	 * interface.
405 	 */
406 	if (IN6_IS_ADDR_LOOPBACK(in6)) {
407 		if (!(ifp->if_flags & IFF_LOOPBACK))
408 			return (EINVAL);
409 	} else {
410 		scope = in6_addrscope(in6);
411 		if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
412 		    scope == IPV6_ADDR_SCOPE_LINKLOCAL) {
413 			/*
414 			 * Currently we use interface indices as the
415 			 * zone IDs for interface-local and link-local
416 			 * scopes.
417 			 */
418 			zoneid = ifp->if_index;
419 			in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */
420 		} else if (scope != IPV6_ADDR_SCOPE_GLOBAL) {
421 			IF_AFDATA_RLOCK(ifp);
422 			sid = SID(ifp);
423 			zoneid = sid->s6id_list[scope];
424 			IF_AFDATA_RUNLOCK(ifp);
425 		}
426 	}
427 
428 	if (ret_id != NULL)
429 		*ret_id = zoneid;
430 
431 	return (0);
432 }
433 
434 /*
435  * Just clear the embedded scope identifier.  Return 0 if the original address
436  * is intact; return non 0 if the address is modified.
437  */
438 int
439 in6_clearscope(struct in6_addr *in6)
440 {
441 	int modified = 0;
442 
443 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
444 		if (in6->s6_addr16[1] != 0)
445 			modified = 1;
446 		in6->s6_addr16[1] = 0;
447 	}
448 
449 	return (modified);
450 }
451 
452 /*
453  * Return the scope identifier or zero.
454  */
455 uint16_t
456 in6_getscope(struct in6_addr *in6)
457 {
458 
459 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6))
460 		return (in6->s6_addr16[1]);
461 
462 	return (0);
463 }
464 
465 /*
466  * Return pointer to ifnet structure, corresponding to the zone id of
467  * link-local scope.
468  */
469 struct ifnet*
470 in6_getlinkifnet(uint32_t zoneid)
471 {
472 
473 	return (ifnet_byindex((u_short)zoneid));
474 }
475 
476 /*
477  * Return zone id for the specified scope.
478  */
479 uint32_t
480 in6_getscopezone(const struct ifnet *ifp, int scope)
481 {
482 
483 	if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
484 	    scope == IPV6_ADDR_SCOPE_LINKLOCAL)
485 		return (ifp->if_index);
486 	if (scope >= 0 && scope < IPV6_ADDR_SCOPES_COUNT)
487 		return (SID(ifp)->s6id_list[scope]);
488 	return (0);
489 }
490 
491 /*
492  * Extracts scope from adddress @dst, stores cleared address
493  * inside @dst and zone inside @scopeid
494  */
495 void
496 in6_splitscope(const struct in6_addr *src, struct in6_addr *dst,
497     uint32_t *scopeid)
498 {
499 	uint32_t zoneid;
500 
501 	*dst = *src;
502 	zoneid = ntohs(in6_getscope(dst));
503 	in6_clearscope(dst);
504 	*scopeid = zoneid;
505 }
506 
507 /*
508  * This function is for checking sockaddr_in6 structure passed
509  * from the application level (usually).
510  *
511  * sin6_scope_id should be set for link-local unicast, link-local and
512  * interface-local  multicast addresses.
513  *
514  * If it is zero, then look into default zone ids. If default zone id is
515  * not set or disabled, then return error.
516  */
517 int
518 sa6_checkzone(struct sockaddr_in6 *sa6)
519 {
520 	int scope;
521 
522 	scope = in6_addrscope(&sa6->sin6_addr);
523 	if (scope == IPV6_ADDR_SCOPE_GLOBAL)
524 		return (sa6->sin6_scope_id ? EINVAL: 0);
525 	if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr) &&
526 	    scope != IPV6_ADDR_SCOPE_LINKLOCAL &&
527 	    scope != IPV6_ADDR_SCOPE_INTFACELOCAL) {
528 		if (sa6->sin6_scope_id == 0 && V_ip6_use_defzone != 0)
529 			sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
530 		return (0);
531 	}
532 	/*
533 	 * Since ::1 address always configured on the lo0, we can
534 	 * automatically set its zone id, when it is not specified.
535 	 * Return error, when specified zone id doesn't match with
536 	 * actual value.
537 	 */
538 	if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) {
539 		if (sa6->sin6_scope_id == 0)
540 			sa6->sin6_scope_id = in6_getscopezone(V_loif, scope);
541 		else if (sa6->sin6_scope_id != in6_getscopezone(V_loif, scope))
542 			return (EADDRNOTAVAIL);
543 	}
544 	/* XXX: we can validate sin6_scope_id here */
545 	if (sa6->sin6_scope_id != 0)
546 		return (0);
547 	if (V_ip6_use_defzone != 0)
548 		sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
549 	/* Return error if we can't determine zone id */
550 	return (sa6->sin6_scope_id ? 0: EADDRNOTAVAIL);
551 }
552 
553 /*
554  * This function is similar to sa6_checkzone, but it uses given ifp
555  * to initialize sin6_scope_id.
556  */
557 int
558 sa6_checkzone_ifp(struct ifnet *ifp, struct sockaddr_in6 *sa6)
559 {
560 	int scope;
561 
562 	scope = in6_addrscope(&sa6->sin6_addr);
563 	if (scope == IPV6_ADDR_SCOPE_LINKLOCAL ||
564 	    scope == IPV6_ADDR_SCOPE_INTFACELOCAL) {
565 		if (sa6->sin6_scope_id == 0) {
566 			sa6->sin6_scope_id = in6_getscopezone(ifp, scope);
567 			return (0);
568 		} else if (sa6->sin6_scope_id != in6_getscopezone(ifp, scope))
569 			return (EADDRNOTAVAIL);
570 	}
571 	return (sa6_checkzone(sa6));
572 }
573 
574 
575