xref: /freebsd/sys/netinet6/scope6.c (revision 595e514d0df2bac5b813d35f83e32875dbf16a83)
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/sysctl.h>
42 #include <sys/syslog.h>
43 
44 #include <net/if.h>
45 #include <net/vnet.h>
46 
47 #include <netinet/in.h>
48 
49 #include <netinet/ip6.h>
50 #include <netinet6/in6_var.h>
51 #include <netinet6/ip6_var.h>
52 #include <netinet6/scope6_var.h>
53 
54 #ifdef ENABLE_DEFAULT_SCOPE
55 VNET_DEFINE(int, ip6_use_defzone) = 1;
56 #else
57 VNET_DEFINE(int, ip6_use_defzone) = 0;
58 #endif
59 VNET_DEFINE(int, deembed_scopeid) = 1;
60 SYSCTL_DECL(_net_inet6_ip6);
61 SYSCTL_VNET_INT(_net_inet6_ip6, OID_AUTO, deembed_scopeid, CTLFLAG_RW,
62     &VNET_NAME(deembed_scopeid), 0,
63     "Extract embedded zone ID and set it to sin6_scope_id in sockaddr_in6.");
64 
65 /*
66  * The scope6_lock protects the global sid default stored in
67  * sid_default below.
68  */
69 static struct mtx scope6_lock;
70 #define	SCOPE6_LOCK_INIT()	mtx_init(&scope6_lock, "scope6_lock", NULL, MTX_DEF)
71 #define	SCOPE6_LOCK()		mtx_lock(&scope6_lock)
72 #define	SCOPE6_UNLOCK()		mtx_unlock(&scope6_lock)
73 #define	SCOPE6_LOCK_ASSERT()	mtx_assert(&scope6_lock, MA_OWNED)
74 
75 static VNET_DEFINE(struct scope6_id, sid_default);
76 #define	V_sid_default			VNET(sid_default)
77 
78 #define SID(ifp) \
79 	(((struct in6_ifextra *)(ifp)->if_afdata[AF_INET6])->scope6_id)
80 
81 void
82 scope6_init(void)
83 {
84 
85 	bzero(&V_sid_default, sizeof(V_sid_default));
86 
87 	if (!IS_DEFAULT_VNET(curvnet))
88 		return;
89 
90 	SCOPE6_LOCK_INIT();
91 }
92 
93 struct scope6_id *
94 scope6_ifattach(struct ifnet *ifp)
95 {
96 	struct scope6_id *sid;
97 
98 	sid = (struct scope6_id *)malloc(sizeof(*sid), M_IFADDR, M_WAITOK);
99 	bzero(sid, sizeof(*sid));
100 
101 	/*
102 	 * XXX: IPV6_ADDR_SCOPE_xxx macros are not standard.
103 	 * Should we rather hardcode here?
104 	 */
105 	sid->s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = ifp->if_index;
106 	sid->s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = ifp->if_index;
107 #ifdef MULTI_SCOPE
108 	/* by default, we don't care about scope boundary for these scopes. */
109 	sid->s6id_list[IPV6_ADDR_SCOPE_SITELOCAL] = 1;
110 	sid->s6id_list[IPV6_ADDR_SCOPE_ORGLOCAL] = 1;
111 #endif
112 
113 	return sid;
114 }
115 
116 void
117 scope6_ifdetach(struct scope6_id *sid)
118 {
119 
120 	free(sid, M_IFADDR);
121 }
122 
123 int
124 scope6_set(struct ifnet *ifp, struct scope6_id *idlist)
125 {
126 	int i;
127 	int error = 0;
128 	struct scope6_id *sid = NULL;
129 
130 	IF_AFDATA_WLOCK(ifp);
131 	sid = SID(ifp);
132 
133 	if (!sid) {	/* paranoid? */
134 		IF_AFDATA_WUNLOCK(ifp);
135 		return (EINVAL);
136 	}
137 
138 	/*
139 	 * XXX: We need more consistency checks of the relationship among
140 	 * scopes (e.g. an organization should be larger than a site).
141 	 */
142 
143 	/*
144 	 * TODO(XXX): after setting, we should reflect the changes to
145 	 * interface addresses, routing table entries, PCB entries...
146 	 */
147 
148 	for (i = 0; i < 16; i++) {
149 		if (idlist->s6id_list[i] &&
150 		    idlist->s6id_list[i] != sid->s6id_list[i]) {
151 			/*
152 			 * An interface zone ID must be the corresponding
153 			 * interface index by definition.
154 			 */
155 			if (i == IPV6_ADDR_SCOPE_INTFACELOCAL &&
156 			    idlist->s6id_list[i] != ifp->if_index) {
157 				IF_AFDATA_WUNLOCK(ifp);
158 				return (EINVAL);
159 			}
160 
161 			if (i == IPV6_ADDR_SCOPE_LINKLOCAL &&
162 			    idlist->s6id_list[i] > V_if_index) {
163 				/*
164 				 * XXX: theoretically, there should be no
165 				 * relationship between link IDs and interface
166 				 * IDs, but we check the consistency for
167 				 * safety in later use.
168 				 */
169 				IF_AFDATA_WUNLOCK(ifp);
170 				return (EINVAL);
171 			}
172 
173 			/*
174 			 * XXX: we must need lots of work in this case,
175 			 * but we simply set the new value in this initial
176 			 * implementation.
177 			 */
178 			sid->s6id_list[i] = idlist->s6id_list[i];
179 		}
180 	}
181 	IF_AFDATA_WUNLOCK(ifp);
182 
183 	return (error);
184 }
185 
186 int
187 scope6_get(struct ifnet *ifp, struct scope6_id *idlist)
188 {
189 	struct scope6_id *sid;
190 
191 	/* We only need to lock the interface's afdata for SID() to work. */
192 	IF_AFDATA_RLOCK(ifp);
193 	sid = SID(ifp);
194 	if (sid == NULL) {	/* paranoid? */
195 		IF_AFDATA_RUNLOCK(ifp);
196 		return (EINVAL);
197 	}
198 
199 	*idlist = *sid;
200 
201 	IF_AFDATA_RUNLOCK(ifp);
202 	return (0);
203 }
204 
205 
206 /*
207  * Get a scope of the address. Node-local, link-local, site-local or global.
208  */
209 int
210 in6_addrscope(struct in6_addr *addr)
211 {
212 	int scope;
213 
214 	if (addr->s6_addr[0] == 0xfe) {
215 		scope = addr->s6_addr[1] & 0xc0;
216 
217 		switch (scope) {
218 		case 0x80:
219 			return IPV6_ADDR_SCOPE_LINKLOCAL;
220 			break;
221 		case 0xc0:
222 			return IPV6_ADDR_SCOPE_SITELOCAL;
223 			break;
224 		default:
225 			return IPV6_ADDR_SCOPE_GLOBAL; /* just in case */
226 			break;
227 		}
228 	}
229 
230 
231 	if (addr->s6_addr[0] == 0xff) {
232 		scope = addr->s6_addr[1] & 0x0f;
233 
234 		/*
235 		 * due to other scope such as reserved,
236 		 * return scope doesn't work.
237 		 */
238 		switch (scope) {
239 		case IPV6_ADDR_SCOPE_INTFACELOCAL:
240 			return IPV6_ADDR_SCOPE_INTFACELOCAL;
241 			break;
242 		case IPV6_ADDR_SCOPE_LINKLOCAL:
243 			return IPV6_ADDR_SCOPE_LINKLOCAL;
244 			break;
245 		case IPV6_ADDR_SCOPE_SITELOCAL:
246 			return IPV6_ADDR_SCOPE_SITELOCAL;
247 			break;
248 		default:
249 			return IPV6_ADDR_SCOPE_GLOBAL;
250 			break;
251 		}
252 	}
253 
254 	/*
255 	 * Regard loopback and unspecified addresses as global, since
256 	 * they have no ambiguity.
257 	 */
258 	if (bcmp(&in6addr_loopback, addr, sizeof(*addr) - 1) == 0) {
259 		if (addr->s6_addr[15] == 1) /* loopback */
260 			return IPV6_ADDR_SCOPE_LINKLOCAL;
261 		if (addr->s6_addr[15] == 0) /* unspecified */
262 			return IPV6_ADDR_SCOPE_GLOBAL; /* XXX: correct? */
263 	}
264 
265 	return IPV6_ADDR_SCOPE_GLOBAL;
266 }
267 
268 /*
269  * ifp - note that this might be NULL
270  */
271 
272 void
273 scope6_setdefault(struct ifnet *ifp)
274 {
275 
276 	/*
277 	 * Currently, this function just sets the default "interfaces"
278 	 * and "links" according to the given interface.
279 	 * We might eventually have to separate the notion of "link" from
280 	 * "interface" and provide a user interface to set the default.
281 	 */
282 	SCOPE6_LOCK();
283 	if (ifp) {
284 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] =
285 			ifp->if_index;
286 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] =
287 			ifp->if_index;
288 	} else {
289 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_INTFACELOCAL] = 0;
290 		V_sid_default.s6id_list[IPV6_ADDR_SCOPE_LINKLOCAL] = 0;
291 	}
292 	SCOPE6_UNLOCK();
293 }
294 
295 int
296 scope6_get_default(struct scope6_id *idlist)
297 {
298 
299 	SCOPE6_LOCK();
300 	*idlist = V_sid_default;
301 	SCOPE6_UNLOCK();
302 
303 	return (0);
304 }
305 
306 u_int32_t
307 scope6_addr2default(struct in6_addr *addr)
308 {
309 	u_int32_t id;
310 
311 	/*
312 	 * special case: The loopback address should be considered as
313 	 * link-local, but there's no ambiguity in the syntax.
314 	 */
315 	if (IN6_IS_ADDR_LOOPBACK(addr))
316 		return (0);
317 
318 	/*
319 	 * XXX: 32-bit read is atomic on all our platforms, is it OK
320 	 * not to lock here?
321 	 */
322 	SCOPE6_LOCK();
323 	id = V_sid_default.s6id_list[in6_addrscope(addr)];
324 	SCOPE6_UNLOCK();
325 	return (id);
326 }
327 
328 /*
329  * Validate the specified scope zone ID in the sin6_scope_id field.  If the ID
330  * is unspecified (=0), needs to be specified, and the default zone ID can be
331  * used, the default value will be used.
332  * This routine then generates the kernel-internal form: if the address scope
333  * of is interface-local or link-local, embed the interface index in the
334  * address.
335  */
336 int
337 sa6_embedscope(struct sockaddr_in6 *sin6, int defaultok)
338 {
339 	u_int32_t zoneid;
340 
341 	if ((zoneid = sin6->sin6_scope_id) == 0 && defaultok)
342 		zoneid = scope6_addr2default(&sin6->sin6_addr);
343 
344 	if (zoneid != 0 &&
345 	    (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
346 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr))) {
347 		/*
348 		 * At this moment, we only check interface-local and
349 		 * link-local scope IDs, and use interface indices as the
350 		 * zone IDs assuming a one-to-one mapping between interfaces
351 		 * and links.
352 		 */
353 		if (V_if_index < zoneid || ifnet_byindex(zoneid) == NULL)
354 			return (ENXIO);
355 
356 		/* XXX assignment to 16bit from 32bit variable */
357 		sin6->sin6_addr.s6_addr16[1] = htons(zoneid & 0xffff);
358 		sin6->sin6_scope_id = 0;
359 	}
360 
361 	return 0;
362 }
363 
364 /*
365  * generate standard sockaddr_in6 from embedded form.
366  */
367 int
368 sa6_recoverscope(struct sockaddr_in6 *sin6)
369 {
370 	char ip6buf[INET6_ADDRSTRLEN];
371 	u_int32_t zoneid;
372 
373 	if (IN6_IS_SCOPE_LINKLOCAL(&sin6->sin6_addr) ||
374 	    IN6_IS_ADDR_MC_INTFACELOCAL(&sin6->sin6_addr)) {
375 		/*
376 		 * KAME assumption: link id == interface id
377 		 */
378 		zoneid = ntohs(sin6->sin6_addr.s6_addr16[1]);
379 		if (zoneid) {
380 			/* sanity check */
381 			if (V_if_index < zoneid)
382 				return (ENXIO);
383 #if 0
384 			/* XXX: Disabled due to possible deadlock. */
385 			if (!ifnet_byindex(zoneid))
386 				return (ENXIO);
387 #endif
388 			if (sin6->sin6_scope_id != 0 &&
389 			    zoneid != sin6->sin6_scope_id) {
390 				log(LOG_NOTICE,
391 				    "%s: embedded scope mismatch: %s%%%d. "
392 				    "sin6_scope_id was overridden.", __func__,
393 				    ip6_sprintf(ip6buf, &sin6->sin6_addr),
394 				    sin6->sin6_scope_id);
395 			}
396 			sin6->sin6_addr.s6_addr16[1] = 0;
397 			sin6->sin6_scope_id = zoneid;
398 		}
399 	}
400 
401 	return 0;
402 }
403 
404 /*
405  * Determine the appropriate scope zone ID for in6 and ifp.  If ret_id is
406  * non NULL, it is set to the zone ID.  If the zone ID needs to be embedded
407  * in the in6_addr structure, in6 will be modified.
408  *
409  * ret_id - unnecessary?
410  */
411 int
412 in6_setscope(struct in6_addr *in6, struct ifnet *ifp, u_int32_t *ret_id)
413 {
414 	int scope;
415 	u_int32_t zoneid = 0;
416 	struct scope6_id *sid;
417 
418 	/*
419 	 * special case: the loopback address can only belong to a loopback
420 	 * interface.
421 	 */
422 	if (IN6_IS_ADDR_LOOPBACK(in6)) {
423 		if (!(ifp->if_flags & IFF_LOOPBACK))
424 			return (EINVAL);
425 	} else {
426 		scope = in6_addrscope(in6);
427 		if (scope == IPV6_ADDR_SCOPE_INTFACELOCAL ||
428 		    scope == IPV6_ADDR_SCOPE_LINKLOCAL) {
429 			/*
430 			 * Currently we use interface indeces as the
431 			 * zone IDs for interface-local and link-local
432 			 * scopes.
433 			 */
434 			zoneid = ifp->if_index;
435 			in6->s6_addr16[1] = htons(zoneid & 0xffff); /* XXX */
436 		} else if (scope != IPV6_ADDR_SCOPE_GLOBAL) {
437 			IF_AFDATA_RLOCK(ifp);
438 			sid = SID(ifp);
439 			zoneid = sid->s6id_list[scope];
440 			IF_AFDATA_RUNLOCK(ifp);
441 		}
442 	}
443 
444 	if (ret_id != NULL)
445 		*ret_id = zoneid;
446 
447 	return (0);
448 }
449 
450 /*
451  * Just clear the embedded scope identifier.  Return 0 if the original address
452  * is intact; return non 0 if the address is modified.
453  */
454 int
455 in6_clearscope(struct in6_addr *in6)
456 {
457 	int modified = 0;
458 
459 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6)) {
460 		if (in6->s6_addr16[1] != 0)
461 			modified = 1;
462 		in6->s6_addr16[1] = 0;
463 	}
464 
465 	return (modified);
466 }
467 
468 /*
469  * Return the scope identifier or zero.
470  */
471 uint16_t
472 in6_getscope(struct in6_addr *in6)
473 {
474 
475 	if (IN6_IS_SCOPE_LINKLOCAL(in6) || IN6_IS_ADDR_MC_INTFACELOCAL(in6))
476 		return (in6->s6_addr16[1]);
477 
478 	return (0);
479 }
480