xref: /freebsd/sys/netinet6/scope6.c (revision 9768746b) 
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/if_private.h>
50 #include <net/vnet.h>
51 
52 #include <netinet/in.h>
53 
54 #include <netinet/ip6.h>
55 #include <netinet6/in6_var.h>
56 #include <netinet6/ip6_var.h>
57 #include <netinet6/scope6_var.h>
58 
59 #ifdef ENABLE_DEFAULT_SCOPE
60 VNET_DEFINE(int, ip6_use_defzone) = 1;
61 #else
62 VNET_DEFINE(int, ip6_use_defzone) = 0;
63 #endif
64 SYSCTL_DECL(_net_inet6_ip6);
65 
66 /*
67  * The scope6_lock protects the global sid default stored in
68  * sid_default below.
69  */
70 static struct mtx scope6_lock;
71 #define	SCOPE6_LOCK_INIT()	mtx_init(&scope6_lock, "scope6_lock", NULL, MTX_DEF)
72 #define	SCOPE6_LOCK()		mtx_lock(&scope6_lock)
73 #define	SCOPE6_UNLOCK()		mtx_unlock(&scope6_lock)
74 #define	SCOPE6_LOCK_ASSERT()	mtx_assert(&scope6_lock, MA_OWNED)
75 
76 VNET_DEFINE_STATIC(struct scope6_id, sid_default);
77 #define	V_sid_default			VNET(sid_default)
78 
79 #define SID(ifp) \
80 	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
81 
82 static int	scope6_get(struct ifnet *, struct scope6_id *);
83 static int	scope6_set(struct ifnet *, struct scope6_id *);
84 
85 void
86 scope6_init(void)
87 {
88 
89 	bzero(&V_sid_default, sizeof(V_sid_default));
90 
91 	if (!IS_DEFAULT_VNET(curvnet))
92 		return;
93 
94 	SCOPE6_LOCK_INIT();
95 }
96 
97 struct scope6_id *
98 scope6_ifattach(struct ifnet *ifp)
99 {
100 	struct scope6_id *sid;
101 
102 	sid = malloc(sizeof(*sid), M_IFADDR, M_WAITOK | M_ZERO);
103 	/*
104 	 * XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
105 	 * Should we rather hardcode here?
106 	 */
107 	sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
108 	sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
109 	return (sid);
110 }
111 
112 void
113 scope6_ifdetach(struct scope6_id *sid)
114 {
115 
116 	free(sid, M_IFADDR);
117 }
118 
119 int
120 scope6_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp)
121 {
122 	struct in6_ifreq *ifr;
123 
124 	if (ifp->if_afdata[AF_INET6] == NULL)
125 		return (EPFNOSUPPORT);
126 
127 	ifr = (struct in6_ifreq *)data;
128 	switch (cmd) {
129 	case SIOCSSCOPE6:
130 		return (scope6_set(ifp,
131 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
132 	case SIOCGSCOPE6:
133 		return (scope6_get(ifp,
134 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
135 	case SIOCGSCOPE6DEF:
136 		return (scope6_get_default(
137 		    (struct scope6_id *)ifr->ifr_ifru.ifru_scope_id));
138 	default:
139 		return (EOPNOTSUPP);
140 	}
141 }
142 
143 static int
144 scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
145 {
146 	int i;
147 	int error = 0;
148 	struct scope6_id *sid = NULL;
149 
150 	IF_AFDATA_WLOCK(ifp);
151 	sid = SID(ifp);
152 
153 	if (!sid) {	/* paranoid? */
154 		IF_AFDATA_WUNLOCK(ifp);
155 		return (EINVAL);
156 	}
157 
158 	/*
159 	 * XXX: We need more consistency checks of the relationship among
160 	 * scopes (e.g. an organization should be larger than a site).
161 	 */
162 
163 	/*
164 	 * TODO(XXX): after setting, we should reflect the changes to
165 	 * interface addresses, routing table entries, PCB entries...
166 	 */
167 
168 	for (i = 0; i < 16; i++) {
169 		if (idlist->s6id_list[i] &&
170 		    idlist->s6id_list[i] != sid->s6id_list[i]) {
171 			/*
172 			 * An interface zone ID must be the corresponding
173 			 * interface index by definition.
174 			 */
175 			if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
176 			    idlist->s6id_list[i] != ifp->if_index) {
177 				IF_AFDATA_WUNLOCK(ifp);
178 				return (EINVAL);
179 			}
180 
181 			if (i == IPV6_ADDR_SCOPE_LINKLOCAL) {
182 				struct epoch_tracker et;
183 
184 				NET_EPOCH_ENTER(et);
185 				if (!ifnet_byindex(idlist->s6id_list[i])) {
186 					/*
187 					 * XXX: theoretically, there should be
188 					 * no relationship between link IDs and
189 					 * interface IDs, but we check the
190 					 * consistency for safety in later use.
191 					 */
192 					NET_EPOCH_EXIT(et);
193 					IF_AFDATA_WUNLOCK(ifp);
194 					return (EINVAL);
195 				}
196 				NET_EPOCH_EXIT(et);
197 			}
198 
199 			/*
200 			 * XXX: we must need lots of work in this case,
201 			 * but we simply set the new value in this initial
202 			 * implementation.
203 			 */
204 			sid->s6id_list[i] = idlist->s6id_list[i];
205 		}
206 	}
207 	IF_AFDATA_WUNLOCK(ifp);
208 
209 	return (error);
210 }
211 
212 static int
213 scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
214 {
215 	struct epoch_tracker et;
216 	struct scope6_id *sid;
217 
218 	/* We only need to lock the interface's afdata for SID() to work. */
219 	NET_EPOCH_ENTER(et);
220 	sid = SID(ifp);
221 	if (sid == NULL) {	/* paranoid? */
222 		NET_EPOCH_EXIT(et);
223 		return (EINVAL);
224 	}
225 
226 	*idlist = *sid;
227 
228 	NET_EPOCH_EXIT(et);
229 	return (0);
230 }
231 
232 /*
233  * Get a scope of the address. Node-local, link-local, site-local or global.
234  */
235 int
236 in6_addrscope(const struct in6_addr *addr)
237 {
238 
239 	if (IN6_IS_ADDR_MULTICAST(addr)) {
240 		/*
241 		 * Addresses with reserved value F must be treated as
242 		 * global multicast addresses.
243 		 */
244 		if (IPV6_ADDR_MC_SCOPE(addr) == 0x0f)
245 			return (IPV6_ADDR_SCOPE_GLOBAL);
246 		return (IPV6_ADDR_MC_SCOPE(addr));
247 	}
248 	if (IN6_IS_ADDR_LINKLOCAL(addr) ||
249 	    IN6_IS_ADDR_LOOPBACK(addr))
250 		return (IPV6_ADDR_SCOPE_LINKLOCAL);
251 	if (IN6_IS_ADDR_SITELOCAL(addr))
252 		return (IPV6_ADDR_SCOPE_SITELOCAL);
253 	return (IPV6_ADDR_SCOPE_GLOBAL);
254 }
255 
256 /*
257  * ifp - note that this might be NULL
258  */
259 
260 void
261 scope6_setdefault(struct ifnet *ifp)
262 {
263 
264 	/*
265 	 * Currently, this function just sets the default "interfaces"
266 	 * and "links" according to the given interface.
267 	 * We might eventually have to separate the notion of "link" from
268 	 * "interface" and provide a user interface to set the default.
269 	 */
270 	SCOPE6_LOCK();
271 	if (ifp) {
272 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
273 			ifp->if_index;
274 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
275 			ifp->if_index;
276 	} else {
277 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
278 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
279 	}
280 	SCOPE6_UNLOCK();
281 }
282 
283 int
284 scope6_get_default(struct scope6_id *idlist)
285 {
286 
287 	SCOPE6_LOCK();
288 	*idlist = V_sid_default;
289 	SCOPE6_UNLOCK();
290 
291 	return (0);
292 }
293 
294 u_int32_t
295 scope6_addr2default(struct in6_addr *addr)
296 {
297 	u_int32_t id;
298 
299 	/*
300 	 * special case: The loopback address should be considered as
301 	 * link-local, but there's no ambiguity in the syntax.
302 	 */
303 	if (IN6_IS_ADDR_LOOPBACK(addr))
304 		return (0);
305 
306 	/*
307 	 * XXX: 32-bit read is atomic on all our platforms, is it OK
308 	 * not to lock here?
309 	 */
310 	SCOPE6_LOCK();
311 	id = V_sid_default.s6id_list[in6_addrscope(addr)];
312 	SCOPE6_UNLOCK();
313 	return (id);
314 }
315 
316 /*
317  * Validate the specified scope zone ID in the sin6_scope_id field.  If the ID
318  * is unspecified (=0), needs to be specified, and the default zone ID can be
319  * used, the default value will be used.
320  * This routine then generates the kernel-internal form: if the address scope
321  * of is interface-local or link-local, embed the interface index in the
322  * address.
323  */
324 int
325 sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
326 {
327 	u_int32_t zoneid;
328 
329 	if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
330 		zoneid = scope6_addr2default(&sin6->sin6_addr);
331 
332 	if (zoneid != 0 &&
333 	    (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
334 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
335 		struct epoch_tracker et;
336 
337 		/*
338 		 * At this moment, we only check interface-local and
339 		 * link-local scope IDs, and use interface indices as the
340 		 * zone IDs assuming a one-to-one mapping between interfaces
341 		 * and links.
342 		 */
343 		NET_EPOCH_ENTER(et);
344 		if (ifnet_byindex(zoneid) == NULL) {
345 			NET_EPOCH_EXIT(et);
346 			return (ENXIO);
347 		}
348 		NET_EPOCH_EXIT(et);
349 
350 		/* XXX assignment to 16bit from 32bit variable */
351 		sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
352 		sin6->sin6_scope_id = 0;
353 	}
354 
355 	return 0;
356 }
357 
358 /*
359  * generate standard sockaddr_in6 from embedded form.
360  */
361 int
362 sa6_recoverscope(struct sockaddr_in6 *sin6)
363 {
364 	char ip6buf[INET6_ADDRSTRLEN];
365 	u_int32_t zoneid;
366 
367 	if (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
368 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr)) {
369 		/*
370 		 * KAME assumption: link id == interface id
371 		 */
372 		zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
373 		if (zoneid) {
374 			struct epoch_tracker et;
375 
376 			NET_EPOCH_ENTER(et);
377 			/* sanity check */
378 			if (!ifnet_byindex(zoneid)) {
379 				NET_EPOCH_EXIT(et);
380 				return (ENXIO);
381 			}
382 			NET_EPOCH_EXIT(et);
383 			if (sin6->sin6_scope_id != 0 &&
384 			    zoneid != sin6->sin6_scope_id) {
385 				log(LOG_NOTICE,
386 				    "%s: embedded scope mismatch: %s%%%d. "
387 				    "sin6_scope_id was overridden\n", __func__,
388 				    ip6_sprintf(ip6buf, &sin6->sin6_addr),
389 				    sin6->sin6_scope_id);
390 			}
391 			sin6->sin6_addr.s6_addr16[1] = 0;
392 			sin6->sin6_scope_id = zoneid;
393 		}
394 	}
395 
396 	return 0;
397 }
398 
399 /*
400  * Determine the appropriate scope zone ID for in6 and ifp.  If ret_id is
401  * non NULL, it is set to the zone ID.  If the zone ID needs to be embedded
402  * in the in6_addr structure, in6 will be modified.
403  *
404  * ret_id - unnecessary?
405  */
406 int
407 in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
408 {
409 	int scope;
410 	u_int32_t zoneid = 0;
411 	struct scope6_id *sid;
412 
413 	/*
414 	 * special case: the loopback address can only belong to a loopback
415 	 * interface.
416 	 */
417 	if (IN6_IS_ADDR_LOOPBACK(in6)) {
418 		if (!(ifp->if_flags & IFF_LOOPBACK))
419 			return (EINVAL);
420 	} else {
421 		scope = in6_addrscope(in6);
422 		if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
423 		    scope == IPV6_ADDR_SCOPE_LINKLOCAL) {
424 			/*
425 			 * Currently we use interface indices as the
426 			 * zone IDs for interface-local and link-local
427 			 * scopes.
428 			 */
429 			zoneid = ifp->if_index;
430 			in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */
431 		} else if (scope != IPV6_ADDR_SCOPE_GLOBAL) {
432 			struct epoch_tracker et;
433 
434 			NET_EPOCH_ENTER(et);
435 			if (ifp->if_afdata[AF_INET6] == NULL) {
436 				NET_EPOCH_EXIT(et);
437 				return (ENETDOWN);
438 			}
439 			sid = SID(ifp);
440 			zoneid = sid->s6id_list[scope];
441 			NET_EPOCH_EXIT(et);
442 		}
443 	}
444 
445 	if (ret_id != NULL)
446 		*ret_id = zoneid;
447 
448 	return (0);
449 }
450 
451 /*
452  * Just clear the embedded scope identifier.  Return 0 if the original address
453  * is intact; return non 0 if the address is modified.
454  */
455 int
456 in6_clearscope(struct in6_addr *in6)
457 {
458 	int modified = 0;
459 
460 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
461 		if (in6->s6_addr16[1] != 0)
462 			modified = 1;
463 		in6->s6_addr16[1] = 0;
464 	}
465 
466 	return (modified);
467 }
468 
469 /*
470  * Return the scope identifier or zero.
471  */
472 uint16_t
473 in6_getscope(const struct in6_addr *in6)
474 {
475 
476 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6))
477 		return (in6->s6_addr16[1]);
478 
479 	return (0);
480 }
481 
482 /*
483  * Returns scope zone id for the unicast address @in6.
484  *
485  * Returns 0 for global unicast and loopback addresses.
486  * Returns interface index for the link-local addresses.
487  */
488 uint32_t
489 in6_get_unicast_scopeid(const struct in6_addr *in6, const struct ifnet *ifp)
490 {
491 
492 	if (IN6_IS_SCOPE_LINKLOCAL(in6))
493 		return (ifp->if_index);
494 	return (0);
495 }
496 
497 void
498 in6_set_unicast_scopeid(struct in6_addr *in6, uint32_t scopeid)
499 {
500 
501 	in6->s6_addr16[1] = htons(scopeid & 0xffff);
502 }
503 
504 /*
505  * Return pointer to ifnet structure, corresponding to the zone id of
506  * link-local scope.
507  */
508 struct ifnet*
509 in6_getlinkifnet(uint32_t zoneid)
510 {
511 
512 	return (ifnet_byindex((u_short)zoneid));
513 }
514 
515 /*
516  * Return zone id for the specified scope.
517  */
518 uint32_t
519 in6_getscopezone(const struct ifnet *ifp, int scope)
520 {
521 
522 	if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
523 	    scope == IPV6_ADDR_SCOPE_LINKLOCAL)
524 		return (ifp->if_index);
525 	if (scope >= 0 && scope < IPV6_ADDR_SCOPES_COUNT)
526 		return (SID(ifp)->s6id_list[scope]);
527 	return (0);
528 }
529 
530 /*
531  * Extracts scope from adddress @dst, stores cleared address
532  * inside @dst and zone inside @scopeid
533  */
534 void
535 in6_splitscope(const struct in6_addr *src, struct in6_addr *dst,
536     uint32_t *scopeid)
537 {
538 	uint32_t zoneid;
539 
540 	*dst = *src;
541 	zoneid = ntohs(in6_getscope(dst));
542 	in6_clearscope(dst);
543 	*scopeid = zoneid;
544 }
545 
546 /*
547  * This function is for checking sockaddr_in6 structure passed
548  * from the application level (usually).
549  *
550  * sin6_scope_id should be set for link-local unicast, link-local and
551  * interface-local  multicast addresses.
552  *
553  * If it is zero, then look into default zone ids. If default zone id is
554  * not set or disabled, then return error.
555  */
556 int
557 sa6_checkzone(struct sockaddr_in6 *sa6)
558 {
559 	int scope;
560 
561 	scope = in6_addrscope(&sa6->sin6_addr);
562 	if (scope == IPV6_ADDR_SCOPE_GLOBAL)
563 		return (sa6->sin6_scope_id ? EINVAL: 0);
564 	if (IN6_IS_ADDR_MULTICAST(&sa6->sin6_addr) &&
565 	    scope != IPV6_ADDR_SCOPE_LINKLOCAL &&
566 	    scope != IPV6_ADDR_SCOPE_INTFACELOCAL) {
567 		if (sa6->sin6_scope_id == 0 && V_ip6_use_defzone != 0)
568 			sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
569 		return (0);
570 	}
571 	/*
572 	 * Since ::1 address always configured on the lo0, we can
573 	 * automatically set its zone id, when it is not specified.
574 	 * Return error, when specified zone id doesn't match with
575 	 * actual value.
576 	 */
577 	if (IN6_IS_ADDR_LOOPBACK(&sa6->sin6_addr)) {
578 		if (sa6->sin6_scope_id == 0)
579 			sa6->sin6_scope_id = in6_getscopezone(V_loif, scope);
580 		else if (sa6->sin6_scope_id != in6_getscopezone(V_loif, scope))
581 			return (EADDRNOTAVAIL);
582 	}
583 	/* XXX: we can validate sin6_scope_id here */
584 	if (sa6->sin6_scope_id != 0)
585 		return (0);
586 	if (V_ip6_use_defzone != 0)
587 		sa6->sin6_scope_id = V_sid_default.s6id_list[scope];
588 	/* Return error if we can't determine zone id */
589 	return (sa6->sin6_scope_id ? 0: EADDRNOTAVAIL);
590 }
591 
592 /*
593  * This function is similar to sa6_checkzone, but it uses given ifp
594  * to initialize sin6_scope_id.
595  */
596 int
597 sa6_checkzone_ifp(struct ifnet *ifp, struct sockaddr_in6 *sa6)
598 {
599 	int scope;
600 
601 	scope = in6_addrscope(&sa6->sin6_addr);
602 	if (scope == IPV6_ADDR_SCOPE_LINKLOCAL ||
603 	    scope == IPV6_ADDR_SCOPE_INTFACELOCAL) {
604 		if (sa6->sin6_scope_id == 0) {
605 			sa6->sin6_scope_id = in6_getscopezone(ifp, scope);
606 			return (0);
607 		} else if (sa6->sin6_scope_id != in6_getscopezone(ifp, scope))
608 			return (EADDRNOTAVAIL);
609 	}
610 	return (sa6_checkzone(sa6));
611 }
612