xref: /freebsd/sys/netinet6/scope6.c (revision 1669d8afc64812c8d2d1d147ae1fd42ff441e1b1)
1 /*-
2  * Copyright (C) 2000 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: scope6.c,v 1.10 2000/07/24 13:29:31 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/malloc.h>
37 #include <sys/mbuf.h>
38 #include <sys/socket.h>
39 #include <sys/systm.h>
40 #include <sys/queue.h>
41 #include <sys/syslog.h>
42 
43 #include <net/route.h>
44 #include <net/if.h>
45 
46 #include <netinet/in.h>
47 
48 #include <netinet6/in6_var.h>
49 #include <netinet6/scope6_var.h>
50 
51 #ifdef ENABLE_DEFAULT_SCOPE
52 int ip6_use_defzone = 1;
53 #else
54 int ip6_use_defzone = 0;
55 #endif
56 
57 /*
58  * The scope6_lock protects the global sid default stored in
59  * sid_default below.
60  */
61 static struct mtx scope6_lock;
62 #define	SCOPE6_LOCK_INIT()	mtx_init(&scope6_lock, "scope6_lock", NULL, MTX_DEF)
63 #define	SCOPE6_LOCK()		mtx_lock(&scope6_lock)
64 #define	SCOPE6_UNLOCK()		mtx_unlock(&scope6_lock)
65 #define	SCOPE6_LOCK_ASSERT()	mtx_assert(&scope6_lock, MA_OWNED)
66 
67 static struct scope6_id sid_default;
68 #define SID(ifp) \
69 	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
70 
71 void
72 scope6_init(void)
73 {
74 
75 	SCOPE6_LOCK_INIT();
76 	bzero(&sid_default, sizeof(sid_default));
77 }
78 
79 struct scope6_id *
80 scope6_ifattach(struct ifnet *ifp)
81 {
82 	struct scope6_id *sid;
83 
84 	sid = (struct scope6_id *)malloc(sizeof(*sid), M_IFADDR, M_WAITOK);
85 	bzero(sid, sizeof(*sid));
86 
87 	/*
88 	 * XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
89 	 * Should we rather hardcode here?
90 	 */
91 	sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
92 	sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
93 #ifdef MULTI_SCOPE
94 	/* by default, we don't care about scope boundary for these scopes. */
95 	sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL] = 1;
96 	sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL] = 1;
97 #endif
98 
99 	return sid;
100 }
101 
102 void
103 scope6_ifdetach(struct scope6_id *sid)
104 {
105 
106 	free(sid, M_IFADDR);
107 }
108 
109 int
110 scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
111 {
112 	int i;
113 	int error = 0;
114 	struct scope6_id *sid = NULL;
115 
116 	IF_AFDATA_LOCK(ifp);
117 	sid = SID(ifp);
118 
119 	if (!sid) {	/* paranoid? */
120 		IF_AFDATA_UNLOCK(ifp);
121 		return (EINVAL);
122 	}
123 
124 	/*
125 	 * XXX: We need more consistency checks of the relationship among
126 	 * scopes (e.g. an organization should be larger than a site).
127 	 */
128 
129 	/*
130 	 * TODO(XXX): after setting, we should reflect the changes to
131 	 * interface addresses, routing table entries, PCB entries...
132 	 */
133 
134 	SCOPE6_LOCK();
135 	for (i = 0; i < 16; i++) {
136 		if (idlist->s6id_list[i] &&
137 		    idlist->s6id_list[i] != sid->s6id_list[i]) {
138 			/*
139 			 * An interface zone ID must be the corresponding
140 			 * interface index by definition.
141 			 */
142 			if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
143 			    idlist->s6id_list[i] != ifp->if_index) {
144 				IF_AFDATA_UNLOCK(ifp);
145 				SCOPE6_UNLOCK();
146 				return (EINVAL);
147 			}
148 
149 			if (i == IPV6_ADDR_SCOPE_LINKLOCAL &&
150 			    idlist->s6id_list[i] > if_index) {
151 				/*
152 				 * XXX: theoretically, there should be no
153 				 * relationship between link IDs and interface
154 				 * IDs, but we check the consistency for
155 				 * safety in later use.
156 				 */
157 				IF_AFDATA_UNLOCK(ifp);
158 				SCOPE6_UNLOCK();
159 				return (EINVAL);
160 			}
161 
162 			/*
163 			 * XXX: we must need lots of work in this case,
164 			 * but we simply set the new value in this initial
165 			 * implementation.
166 			 */
167 			sid->s6id_list[i] = idlist->s6id_list[i];
168 		}
169 	}
170 	SCOPE6_UNLOCK();
171 	IF_AFDATA_UNLOCK(ifp);
172 
173 	return (error);
174 }
175 
176 int
177 scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
178 {
179 	/* We only need to lock the interface's afdata for SID() to work. */
180 	IF_AFDATA_LOCK(ifp);
181 	struct scope6_id *sid = SID(ifp);
182 
183 	if (sid == NULL) {	/* paranoid? */
184 		IF_AFDATA_UNLOCK(ifp);
185 		return (EINVAL);
186 	}
187 
188 	SCOPE6_LOCK();
189 	*idlist = *sid;
190 	SCOPE6_UNLOCK();
191 
192 	IF_AFDATA_UNLOCK(ifp);
193 	return (0);
194 }
195 
196 
197 /*
198  * Get a scope of the address. Node-local, link-local, site-local or global.
199  */
200 int
201 in6_addrscope(struct in6_addr *addr)
202 {
203 	int scope;
204 
205 	if (addr->s6_addr[0] == 0xfe) {
206 		scope = addr->s6_addr[1] & 0xc0;
207 
208 		switch (scope) {
209 		case 0x80:
210 			return IPV6_ADDR_SCOPE_LINKLOCAL;
211 			break;
212 		case 0xc0:
213 			return IPV6_ADDR_SCOPE_SITELOCAL;
214 			break;
215 		default:
216 			return IPV6_ADDR_SCOPE_GLOBAL; /* just in case */
217 			break;
218 		}
219 	}
220 
221 
222 	if (addr->s6_addr[0] == 0xff) {
223 		scope = addr->s6_addr[1] & 0x0f;
224 
225 		/*
226 		 * due to other scope such as reserved,
227 		 * return scope doesn't work.
228 		 */
229 		switch (scope) {
230 		case IPV6_ADDR_SCOPE_INTFACELOCAL:
231 			return IPV6_ADDR_SCOPE_INTFACELOCAL;
232 			break;
233 		case IPV6_ADDR_SCOPE_LINKLOCAL:
234 			return IPV6_ADDR_SCOPE_LINKLOCAL;
235 			break;
236 		case IPV6_ADDR_SCOPE_SITELOCAL:
237 			return IPV6_ADDR_SCOPE_SITELOCAL;
238 			break;
239 		default:
240 			return IPV6_ADDR_SCOPE_GLOBAL;
241 			break;
242 		}
243 	}
244 
245 	/*
246 	 * Regard loopback and unspecified addresses as global, since
247 	 * they have no ambiguity.
248 	 */
249 	if (bcmp(&in6addr_loopback, addr, sizeof(*addr) - 1) == 0) {
250 		if (addr->s6_addr[15] == 1) /* loopback */
251 			return IPV6_ADDR_SCOPE_LINKLOCAL;
252 		if (addr->s6_addr[15] == 0) /* unspecified */
253 			return IPV6_ADDR_SCOPE_GLOBAL; /* XXX: correct? */
254 	}
255 
256 	return IPV6_ADDR_SCOPE_GLOBAL;
257 }
258 
259 /*
260  * ifp - note that this might be NULL
261  */
262 
263 void
264 scope6_setdefault(struct ifnet *ifp)
265 {
266 	/*
267 	 * Currently, this function just sets the default "interfaces"
268 	 * and "links" according to the given interface.
269 	 * We might eventually have to separate the notion of "link" from
270 	 * "interface" and provide a user interface to set the default.
271 	 */
272 	SCOPE6_LOCK();
273 	if (ifp) {
274 		sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
275 			ifp->if_index;
276 		sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
277 			ifp->if_index;
278 	} else {
279 		sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
280 		sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
281 	}
282 	SCOPE6_UNLOCK();
283 }
284 
285 int
286 scope6_get_default(struct scope6_id *idlist)
287 {
288 
289 	SCOPE6_LOCK();
290 	*idlist = sid_default;
291 	SCOPE6_UNLOCK();
292 
293 	return (0);
294 }
295 
296 u_int32_t
297 scope6_addr2default(struct in6_addr *addr)
298 {
299 	u_int32_t id;
300 
301 	/*
302 	 * special case: The loopback address should be considered as
303 	 * link-local, but there's no ambiguity in the syntax.
304 	 */
305 	if (IN6_IS_ADDR_LOOPBACK(addr))
306 		return (0);
307 
308 	/*
309 	 * XXX: 32-bit read is atomic on all our platforms, is it OK
310 	 * not to lock here?
311 	 */
312 	SCOPE6_LOCK();
313 	id = sid_default.s6id_list[in6_addrscope(addr)];
314 	SCOPE6_UNLOCK();
315 	return (id);
316 }
317 
318 /*
319  * Validate the specified scope zone ID in the sin6_scope_id field.  If the ID
320  * is unspecified (=0), needs to be specified, and the default zone ID can be
321  * used, the default value will be used.
322  * This routine then generates the kernel-internal form: if the address scope
323  * of is interface-local or link-local, embed the interface index in the
324  * address.
325  */
326 int
327 sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
328 {
329 	struct ifnet *ifp;
330 	u_int32_t zoneid;
331 
332 	if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
333 		zoneid = scope6_addr2default(&sin6->sin6_addr);
334 
335 	if (zoneid != 0 &&
336 	    (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
337 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
338 		/*
339 		 * At this moment, we only check interface-local and
340 		 * link-local scope IDs, and use interface indices as the
341 		 * zone IDs assuming a one-to-one mapping between interfaces
342 		 * and links.
343 		 */
344 		if (if_index < zoneid)
345 			return (ENXIO);
346 		ifp = ifnet_byindex(zoneid);
347 		if (ifp == NULL) /* XXX: this can happen for some OS */
348 			return (ENXIO);
349 
350 		/* XXX assignment to 16bit from 32bit variable */
351 		sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
352 
353 		sin6->sin6_scope_id = 0;
354 	}
355 
356 	return 0;
357 }
358 
359 /*
360  * generate standard sockaddr_in6 from embedded form.
361  */
362 int
363 sa6_recoverscope(struct sockaddr_in6 *sin6)
364 {
365 	char ip6buf[INET6_ADDRSTRLEN];
366 	u_int32_t zoneid;
367 
368 	if (sin6->sin6_scope_id != 0) {
369 		log(LOG_NOTICE,
370 		    "sa6_recoverscope: assumption failure (non 0 ID): %s%%%d\n",
371 		    ip6_sprintf(ip6buf, &sin6->sin6_addr), sin6->sin6_scope_id);
372 		/* XXX: proceed anyway... */
373 	}
374 	if (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
375 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr)) {
376 		/*
377 		 * KAME assumption: link id == interface id
378 		 */
379 		zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
380 		if (zoneid) {
381 			/* sanity check */
382 			if (zoneid < 0 || if_index < zoneid)
383 				return (ENXIO);
384 			if (!ifnet_byindex(zoneid))
385 				return (ENXIO);
386 			sin6->sin6_addr.s6_addr16[1] = 0;
387 			sin6->sin6_scope_id = zoneid;
388 		}
389 	}
390 
391 	return 0;
392 }
393 
394 /*
395  * Determine the appropriate scope zone ID for in6 and ifp.  If ret_id is
396  * non NULL, it is set to the zone ID.  If the zone ID needs to be embedded
397  * in the in6_addr structure, in6 will be modified.
398  *
399  * ret_id - unnecessary?
400  */
401 int
402 in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
403 {
404 	int scope;
405 	u_int32_t zoneid = 0;
406 	struct scope6_id *sid;
407 
408 	IF_AFDATA_LOCK(ifp);
409 
410 	sid = SID(ifp);
411 
412 #ifdef DIAGNOSTIC
413 	if (sid == NULL) { /* should not happen */
414 		panic("in6_setscope: scope array is NULL");
415 		/* NOTREACHED */
416 	}
417 #endif
418 
419 	/*
420 	 * special case: the loopback address can only belong to a loopback
421 	 * interface.
422 	 */
423 	if (IN6_IS_ADDR_LOOPBACK(in6)) {
424 		if (!(ifp->if_flags & IFF_LOOPBACK)) {
425 			IF_AFDATA_UNLOCK(ifp);
426 			return (EINVAL);
427 		} else {
428 			if (ret_id != NULL)
429 				*ret_id = 0; /* there's no ambiguity */
430 			IF_AFDATA_UNLOCK(ifp);
431 			return (0);
432 		}
433 	}
434 
435 	scope = in6_addrscope(in6);
436 
437 	SCOPE6_LOCK();
438 	switch (scope) {
439 	case IPV6_ADDR_SCOPE_INTFACELOCAL: /* should be interface index */
440 		zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL];
441 		break;
442 
443 	case IPV6_ADDR_SCOPE_LINKLOCAL:
444 		zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL];
445 		break;
446 
447 	case IPV6_ADDR_SCOPE_SITELOCAL:
448 		zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL];
449 		break;
450 
451 	case IPV6_ADDR_SCOPE_ORGLOCAL:
452 		zoneid = sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL];
453 		break;
454 
455 	default:
456 		zoneid = 0;	/* XXX: treat as global. */
457 		break;
458 	}
459 	SCOPE6_UNLOCK();
460 	IF_AFDATA_UNLOCK(ifp);
461 
462 	if (ret_id != NULL)
463 		*ret_id = zoneid;
464 
465 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6))
466 		in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */
467 
468 	return (0);
469 }
470 
471 /*
472  * Just clear the embedded scope identifier.  Return 0 if the original address
473  * is intact; return non 0 if the address is modified.
474  */
475 int
476 in6_clearscope(struct in6_addr *in6)
477 {
478 	int modified = 0;
479 
480 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
481 		if (in6->s6_addr16[1] != 0)
482 			modified = 1;
483 		in6->s6_addr16[1] = 0;
484 	}
485 
486 	return (modified);
487 }
488