xref: /netbsd-src/sys/netinet6/in6_ifattach.c (revision 63aea4bd5b445e491ff0389fe27ec78b3099dba3)
1 /*	$NetBSD: in6_ifattach.c,v 1.95 2015/02/23 19:15:59 martin Exp $	*/
2 /*	$KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei 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 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: in6_ifattach.c,v 1.95 2015/02/23 19:15:59 martin Exp $");
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kmem.h>
39 #include <sys/socket.h>
40 #include <sys/sockio.h>
41 #include <sys/kernel.h>
42 #include <sys/syslog.h>
43 #include <sys/md5.h>
44 #include <sys/socketvar.h>
45 #include <sys/cprng.h>
46 
47 #include <net/if.h>
48 #include <net/if_dl.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_var.h>
54 
55 #include <netinet/ip6.h>
56 #include <netinet6/in6_ifattach.h>
57 #include <netinet6/ip6_var.h>
58 #include <netinet6/nd6.h>
59 #include <netinet6/ip6_mroute.h>
60 #include <netinet6/scope6_var.h>
61 
62 #include <net/net_osdep.h>
63 
64 unsigned long in6_maxmtu = 0;
65 
66 int ip6_auto_linklocal = 1;	/* enable by default */
67 
68 callout_t in6_tmpaddrtimer_ch;
69 
70 
71 #if 0
72 static int get_hostid_ifid(struct ifnet *, struct in6_addr *);
73 #endif
74 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
75 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
76 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
77 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
78 static int in6_ifattach_loopback(struct ifnet *);
79 
80 #define EUI64_GBIT	0x01
81 #define EUI64_UBIT	0x02
82 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (/*CONSTCOND*/ 0)
83 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
84 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
85 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
86 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
87 
88 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
89 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
90 
91 #define GEN_TEMPID_RETRY_MAX 5
92 
93 #if 0
94 /*
95  * Generate a last-resort interface identifier from hostid.
96  * works only for certain architectures (like sparc).
97  * also, using hostid itself may constitute a privacy threat, much worse
98  * than MAC addresses (hostids are used for software licensing).
99  * maybe we should use MD5(hostid) instead.
100  *
101  * in6 - upper 64bits are preserved
102  */
103 static int
104 get_hostid_ifid(struct ifnet *ifp, struct in6_addr *in6)
105 {
106 	int off, len;
107 	static const uint8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
108 	static const uint8_t allone[8] =
109 	    { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
110 
111 	if (!hostid)
112 		return -1;
113 
114 	/* get up to 8 bytes from the hostid field - should we get */
115 	len = (sizeof(hostid) > 8) ? 8 : sizeof(hostid);
116 	off = sizeof(*in6) - len;
117 	memcpy(&in6->s6_addr[off], &hostid, len);
118 
119 	/* make sure we do not return anything bogus */
120 	if (memcmp(&in6->s6_addr[8], allzero, sizeof(allzero)))
121 		return -1;
122 	if (memcmp(&in6->s6_addr[8], allone, sizeof(allone)))
123 		return -1;
124 
125 	/* make sure to set "u" bit to local, and "g" bit to individual. */
126 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
127 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
128 
129 	/* convert EUI64 into IPv6 interface identifier */
130 	EUI64_TO_IFID(in6);
131 
132 	return 0;
133 }
134 #endif
135 
136 /*
137  * Generate a last-resort interface identifier, when the machine has no
138  * IEEE802/EUI64 address sources.
139  * The goal here is to get an interface identifier that is
140  * (1) random enough and (2) does not change across reboot.
141  * We currently use MD5(hostname) for it.
142  */
143 static int
144 get_rand_ifid(struct ifnet *ifp,
145 	struct in6_addr *in6)	/* upper 64bits are preserved */
146 {
147 	MD5_CTX ctxt;
148 	u_int8_t digest[16];
149 
150 #if 0
151 	/* we need at least several letters as seed for ifid */
152 	if (hostnamelen < 3)
153 		return -1;
154 #endif
155 
156 	/* generate 8 bytes of pseudo-random value. */
157 	memset(&ctxt, 0, sizeof(ctxt));
158 	MD5Init(&ctxt);
159 	MD5Update(&ctxt, (u_char *)hostname, hostnamelen);
160 	MD5Final(digest, &ctxt);
161 
162 	/* assumes sizeof(digest) > sizeof(ifid) */
163 	memcpy(&in6->s6_addr[8], digest, 8);
164 
165 	/* make sure to set "u" bit to local, and "g" bit to individual. */
166 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
167 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
168 
169 	/* convert EUI64 into IPv6 interface identifier */
170 	EUI64_TO_IFID(in6);
171 
172 	return 0;
173 }
174 
175 static int
176 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
177 {
178 	MD5_CTX ctxt;
179 	u_int8_t seed[16], digest[16], nullbuf[8];
180 	/*
181 	 * interface ID for subnet anycast addresses.
182 	 * XXX: we assume the unicast address range that requires IDs
183 	 * in EUI-64 format.
184 	 */
185 	static const uint8_t anycast_id[8] = { 0xfd, 0xff, 0xff, 0xff,
186 	    0xff, 0xff, 0xff, 0x80 };
187 	static const uint8_t isatap_id[4] = { 0x00, 0x00, 0x5e, 0xfe };
188 	int badid, retry = 0;
189 
190 	/* If there's no hisotry, start with a random seed. */
191 	memset(nullbuf, 0, sizeof(nullbuf));
192 	if (memcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
193 		cprng_fast(seed, sizeof(seed));
194 	} else
195 		memcpy(seed, seed0, 8);
196 
197 	/* copy the right-most 64-bits of the given address */
198 	/* XXX assumption on the size of IFID */
199 	memcpy(&seed[8], seed1, 8);
200 
201   again:
202 	/* for debugging purposes only */
203 #if 0
204 	{
205 		int i;
206 
207 		printf("generate_tmp_ifid: new randomized ID from: ");
208 		for (i = 0; i < 16; i++)
209 			printf("%02x", seed[i]);
210 		printf(" ");
211 	}
212 #endif
213 
214 	/* generate 16 bytes of pseudo-random value. */
215 	memset(&ctxt, 0, sizeof(ctxt));
216 	MD5Init(&ctxt);
217 	MD5Update(&ctxt, seed, sizeof(seed));
218 	MD5Final(digest, &ctxt);
219 
220 	/*
221 	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (3)
222 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
223 	 * left-most bit is numbered 0) to zero.
224 	 */
225 	memcpy(ret, digest, 8);
226 	ret[0] &= ~EUI64_UBIT;
227 
228 	/*
229 	 * Reject inappropriate identifiers according to
230 	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (4)
231 	 * At this moment, we reject following cases:
232 	 * - all 0 identifier
233 	 * - identifiers that conflict with reserved subnet anycast addresses,
234 	 *   which are defined in RFC 2526.
235 	 * - identifiers that conflict with ISATAP addresses
236 	 * - identifiers used in our own addresses
237 	 */
238 	badid = 0;
239 	if (memcmp(nullbuf, ret, sizeof(nullbuf)) == 0)
240 		badid = 1;
241 	else if (memcmp(anycast_id, ret, 7) == 0 &&
242 	    (anycast_id[7] & ret[7]) == anycast_id[7]) {
243 		badid = 1;
244 	} else if (memcmp(isatap_id, ret, sizeof(isatap_id)) == 0)
245 		badid = 1;
246 	else {
247 		struct in6_ifaddr *ia;
248 
249 		for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
250 			if (!memcmp(&ia->ia_addr.sin6_addr.s6_addr[8],
251 			    ret, 8)) {
252 				badid = 1;
253 				break;
254 			}
255 		}
256 	}
257 
258 	/*
259 	 * In the event that an unacceptable identifier has been generated,
260 	 * restart the process, using the right-most 64 bits of the MD5 digest
261 	 * obtained in place of the history value.
262 	 */
263 	if (badid) {
264 		/* for debugging purposes only */
265 #if 0
266 		{
267 			int i;
268 
269 			printf("unacceptable random ID: ");
270 			for (i = 0; i < 16; i++)
271 				printf("%02x", digest[i]);
272 			printf("\n");
273 		}
274 #endif
275 
276 		if (++retry < GEN_TEMPID_RETRY_MAX) {
277 			memcpy(seed, &digest[8], 8);
278 			goto again;
279 		} else {
280 			/*
281 			 * We're so unlucky.  Give up for now, and return
282 			 * all 0 IDs to tell the caller not to make a
283 			 * temporary address.
284 			 */
285 			nd6log((LOG_NOTICE,
286 			    "generate_tmp_ifid: never found a good ID\n"));
287 			memset(ret, 0, 8);
288 		}
289 	}
290 
291 	/*
292 	 * draft-ietf-ipngwg-temp-addresses-v2-00.txt 3.2.1. (6)
293 	 * Take the rightmost 64-bits of the MD5 digest and save them in
294 	 * stable storage as the history value to be used in the next
295 	 * iteration of the algorithm.
296 	 */
297 	memcpy(seed0, &digest[8], 8);
298 
299 	/* for debugging purposes only */
300 #if 0
301 	{
302 		int i;
303 
304 		printf("to: ");
305 		for (i = 0; i < 16; i++)
306 			printf("%02x", digest[i]);
307 		printf("\n");
308 	}
309 #endif
310 
311 	return 0;
312 }
313 
314 /*
315  * Get interface identifier for the specified interface.
316  *
317  * in6 - upper 64bits are preserved
318  */
319 int
320 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
321 {
322 	struct ifaddr *ifa;
323 	const struct sockaddr_dl *sdl = NULL, *tsdl;
324 	const char *addr;
325 	size_t addrlen;
326 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
327 	static u_int8_t allone[8] =
328 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
329 
330 	IFADDR_FOREACH(ifa, ifp) {
331 		if (ifa->ifa_addr->sa_family != AF_LINK)
332 			continue;
333 		tsdl = satocsdl(ifa->ifa_addr);
334 		if (tsdl == NULL || tsdl->sdl_alen == 0)
335 			continue;
336 		if (sdl == NULL || ifa == ifp->if_dl || ifa == ifp->if_hwdl)
337 			sdl = tsdl;
338 		if (ifa == ifp->if_hwdl)
339 			break;
340 	}
341 
342 	if (sdl == NULL)
343 		return -1;
344 
345 	addr = CLLADDR(sdl);
346 	addrlen = sdl->sdl_alen;
347 
348 	switch (ifp->if_type) {
349 	case IFT_IEEE1394:
350 	case IFT_IEEE80211:
351 		/* IEEE1394 uses 16byte length address starting with EUI64 */
352 		if (addrlen > 8)
353 			addrlen = 8;
354 		break;
355 	default:
356 		break;
357 	}
358 
359 	/* get EUI64 */
360 	switch (ifp->if_type) {
361 	/* IEEE802/EUI64 cases - what others? */
362 	case IFT_ETHER:
363 	case IFT_FDDI:
364 	case IFT_ATM:
365 	case IFT_IEEE1394:
366 	case IFT_IEEE80211:
367 		/* look at IEEE802/EUI64 only */
368 		if (addrlen != 8 && addrlen != 6)
369 			return -1;
370 
371 		/*
372 		 * check for invalid MAC address - on bsdi, we see it a lot
373 		 * since wildboar configures all-zero MAC on pccard before
374 		 * card insertion.
375 		 */
376 		if (memcmp(addr, allzero, addrlen) == 0)
377 			return -1;
378 		if (memcmp(addr, allone, addrlen) == 0)
379 			return -1;
380 
381 		/* make EUI64 address */
382 		if (addrlen == 8)
383 			memcpy(&in6->s6_addr[8], addr, 8);
384 		else if (addrlen == 6) {
385 			in6->s6_addr[8] = addr[0];
386 			in6->s6_addr[9] = addr[1];
387 			in6->s6_addr[10] = addr[2];
388 			in6->s6_addr[11] = 0xff;
389 			in6->s6_addr[12] = 0xfe;
390 			in6->s6_addr[13] = addr[3];
391 			in6->s6_addr[14] = addr[4];
392 			in6->s6_addr[15] = addr[5];
393 		}
394 		break;
395 
396 	case IFT_ARCNET:
397 		if (addrlen != 1)
398 			return -1;
399 		if (!addr[0])
400 			return -1;
401 
402 		memset(&in6->s6_addr[8], 0, 8);
403 		in6->s6_addr[15] = addr[0];
404 
405 		/*
406 		 * due to insufficient bitwidth, we mark it local.
407 		 */
408 		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
409 		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
410 		break;
411 
412 	case IFT_GIF:
413 #ifdef IFT_STF
414 	case IFT_STF:
415 #endif
416 		/*
417 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
418 		 * however, IPv4 address is not very suitable as unique
419 		 * identifier source (can be renumbered).
420 		 * we don't do this.
421 		 */
422 		return -1;
423 
424 	default:
425 		return -1;
426 	}
427 
428 	/* sanity check: g bit must not indicate "group" */
429 	if (EUI64_GROUP(in6))
430 		return -1;
431 
432 	/* convert EUI64 into IPv6 interface identifier */
433 	EUI64_TO_IFID(in6);
434 
435 	/*
436 	 * sanity check: ifid must not be all zero, avoid conflict with
437 	 * subnet router anycast
438 	 */
439 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
440 	    memcmp(&in6->s6_addr[9], allzero, 7) == 0) {
441 		return -1;
442 	}
443 
444 	return 0;
445 }
446 
447 /*
448  * Get interface identifier for the specified interface.  If it is not
449  * available on ifp0, borrow interface identifier from other information
450  * sources.
451  *
452  * altifp - secondary EUI64 source
453  */
454 static int
455 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
456 	struct in6_addr *in6)
457 {
458 	struct ifnet *ifp;
459 
460 	/* first, try to get it from the interface itself */
461 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
462 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
463 		    if_name(ifp0)));
464 		goto success;
465 	}
466 
467 	/* try secondary EUI64 source. this basically is for ATM PVC */
468 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
469 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
470 		    if_name(ifp0), if_name(altifp)));
471 		goto success;
472 	}
473 
474 	/* next, try to get it from some other hardware interface */
475 	IFNET_FOREACH(ifp) {
476 		if (ifp == ifp0)
477 			continue;
478 		if (in6_get_hw_ifid(ifp, in6) != 0)
479 			continue;
480 
481 		/*
482 		 * to borrow ifid from other interface, ifid needs to be
483 		 * globally unique
484 		 */
485 		if (IFID_UNIVERSAL(in6)) {
486 			nd6log((LOG_DEBUG,
487 			    "%s: borrow interface identifier from %s\n",
488 			    if_name(ifp0), if_name(ifp)));
489 			goto success;
490 		}
491 	}
492 
493 #if 0
494 	/* get from hostid - only for certain architectures */
495 	if (get_hostid_ifid(ifp, in6) == 0) {
496 		nd6log((LOG_DEBUG,
497 		    "%s: interface identifier generated by hostid\n",
498 		    if_name(ifp0)));
499 		goto success;
500 	}
501 #endif
502 
503 	/* last resort: get from random number source */
504 	if (get_rand_ifid(ifp, in6) == 0) {
505 		nd6log((LOG_DEBUG,
506 		    "%s: interface identifier generated by random number\n",
507 		    if_name(ifp0)));
508 		goto success;
509 	}
510 
511 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
512 	return -1;
513 
514 success:
515 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
516 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
517 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
518 	    in6->s6_addr[14], in6->s6_addr[15]));
519 	return 0;
520 }
521 
522 /*
523  * altifp - secondary EUI64 source
524  */
525 
526 static int
527 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
528 {
529 	struct in6_ifaddr *ia __diagused;
530 	struct in6_aliasreq ifra;
531 	struct nd_prefixctl prc0;
532 	int i, error;
533 
534 	/*
535 	 * configure link-local address.
536 	 */
537 	memset(&ifra, 0, sizeof(ifra));
538 
539 	/*
540 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
541 	 * for safety.
542 	 */
543 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
544 
545 	ifra.ifra_addr.sin6_family = AF_INET6;
546 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
547 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
548 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
549 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
550 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
551 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
552 	} else {
553 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
554 			nd6log((LOG_ERR,
555 			    "%s: no ifid available\n", if_name(ifp)));
556 			return -1;
557 		}
558 	}
559 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
560 		return -1;
561 
562 	sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask64, 0, 0, 0);
563 	/* link-local addresses should NEVER expire. */
564 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
565 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
566 
567 	/*
568 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
569 	 * a link-local address. We can set the 3rd argument to NULL, because
570 	 * we know there's no other link-local address on the interface
571 	 * and therefore we are adding one (instead of updating one).
572 	 */
573 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
574 	    IN6_IFAUPDATE_DADDELAY)) != 0) {
575 		/*
576 		 * XXX: When the interface does not support IPv6, this call
577 		 * would fail in the SIOCINITIFADDR ioctl.  I believe the
578 		 * notification is rather confusing in this case, so just
579 		 * suppress it.  (jinmei@kame.net 20010130)
580 		 */
581 		if (error != EAFNOSUPPORT)
582 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
583 			    "configure a link-local address on %s "
584 			    "(errno=%d)\n",
585 			    if_name(ifp), error));
586 		return -1;
587 	}
588 
589 	ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
590 	KASSERTMSG(ia, "ia == NULL in in6_ifattach_linklocal");
591 
592 	/*
593 	 * Make the link-local prefix (fe80::/64%link) as on-link.
594 	 * Since we'd like to manage prefixes separately from addresses,
595 	 * we make an ND6 prefix structure for the link-local prefix,
596 	 * and add it to the prefix list as a never-expire prefix.
597 	 * XXX: this change might affect some existing code base...
598 	 */
599 	memset(&prc0, 0, sizeof(prc0));
600 	prc0.ndprc_ifp = ifp;
601 	/* this should be 64 at this moment. */
602 	prc0.ndprc_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
603 	prc0.ndprc_prefix = ifra.ifra_addr;
604 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
605 	for (i = 0; i < 4; i++) {
606 		prc0.ndprc_prefix.sin6_addr.s6_addr32[i] &=
607 		    in6mask64.s6_addr32[i];
608 	}
609 	/*
610 	 * Initialize parameters.  The link-local prefix must always be
611 	 * on-link, and its lifetimes never expire.
612 	 */
613 	prc0.ndprc_raf_onlink = 1;
614 	prc0.ndprc_raf_auto = 1;	/* probably meaningless */
615 	prc0.ndprc_vltime = ND6_INFINITE_LIFETIME;
616 	prc0.ndprc_pltime = ND6_INFINITE_LIFETIME;
617 	/*
618 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
619 	 * probably returns NULL.  However, we cannot always expect the result.
620 	 * For example, if we first remove the (only) existing link-local
621 	 * address, and then reconfigure another one, the prefix is still
622 	 * valid with referring to the old link-local address.
623 	 */
624 	if (nd6_prefix_lookup(&prc0) == NULL) {
625 		if ((error = nd6_prelist_add(&prc0, NULL, NULL)) != 0)
626 			return error;
627 	}
628 
629 	return 0;
630 }
631 
632 /*
633  * ifp - mut be IFT_LOOP
634  */
635 
636 static int
637 in6_ifattach_loopback(struct ifnet *ifp)
638 {
639 	struct in6_aliasreq ifra;
640 	int error;
641 
642 	memset(&ifra, 0, sizeof(ifra));
643 
644 	/*
645 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
646 	 * for safety.
647 	 */
648 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
649 
650 	sockaddr_in6_init(&ifra.ifra_prefixmask, &in6mask128, 0, 0, 0);
651 
652 	/*
653 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
654 	 * address.  Follows IPv4 practice - see in_ifinit().
655 	 */
656 	sockaddr_in6_init(&ifra.ifra_dstaddr, &in6addr_loopback, 0, 0, 0);
657 
658 	sockaddr_in6_init(&ifra.ifra_addr, &in6addr_loopback, 0, 0, 0);
659 
660 	/* the loopback  address should NEVER expire. */
661 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
662 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
663 
664 	/* we don't need to perform DAD on loopback interfaces. */
665 	ifra.ifra_flags |= IN6_IFF_NODAD;
666 
667 	/*
668 	 * We are sure that this is a newly assigned address, so we can set
669 	 * NULL to the 3rd arg.
670 	 */
671 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
672 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
673 		    "the loopback address on %s (errno=%d)\n",
674 		    if_name(ifp), error));
675 		return -1;
676 	}
677 
678 	return 0;
679 }
680 
681 /*
682  * compute NI group address, based on the current hostname setting.
683  * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
684  *
685  * when ifp == NULL, the caller is responsible for filling scopeid.
686  */
687 int
688 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
689 	struct sockaddr_in6 *sa6)
690 {
691 	const char *p;
692 	u_int8_t *q;
693 	MD5_CTX ctxt;
694 	u_int8_t digest[16];
695 	u_int8_t l;
696 	u_int8_t n[64];	/* a single label must not exceed 63 chars */
697 
698 	if (!namelen || !name)
699 		return -1;
700 
701 	p = name;
702 	while (p && *p && *p != '.' && p - name < namelen)
703 		p++;
704 	if (p - name > sizeof(n) - 1)
705 		return -1;	/* label too long */
706 	l = p - name;
707 	strncpy((char *)n, name, l);
708 	n[(int)l] = '\0';
709 	for (q = n; *q; q++) {
710 		if ('A' <= *q && *q <= 'Z')
711 			*q = *q - 'A' + 'a';
712 	}
713 
714 	/* generate 8 bytes of pseudo-random value. */
715 	memset(&ctxt, 0, sizeof(ctxt));
716 	MD5Init(&ctxt);
717 	MD5Update(&ctxt, &l, sizeof(l));
718 	MD5Update(&ctxt, n, l);
719 	MD5Final(digest, &ctxt);
720 
721 	memset(sa6, 0, sizeof(*sa6));
722 	sa6->sin6_family = AF_INET6;
723 	sa6->sin6_len = sizeof(*sa6);
724 	sa6->sin6_addr.s6_addr16[0] = htons(0xff02);
725 	sa6->sin6_addr.s6_addr8[11] = 2;
726 	memcpy(&sa6->sin6_addr.s6_addr32[3], digest,
727 	    sizeof(sa6->sin6_addr.s6_addr32[3]));
728 	if (in6_setscope(&sa6->sin6_addr, ifp, NULL))
729 		return -1; /* XXX: should not fail */
730 
731 	return 0;
732 }
733 
734 /*
735  * XXX multiple loopback interface needs more care.  for instance,
736  * nodelocal address needs to be configured onto only one of them.
737  * XXX multiple link-local address case
738  *
739  * altifp - secondary EUI64 source
740  */
741 void
742 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
743 {
744 	struct in6_ifaddr *ia;
745 	struct in6_addr in6;
746 
747 	/* some of the interfaces are inherently not IPv6 capable */
748 	switch (ifp->if_type) {
749 	case IFT_BRIDGE:
750 #ifdef IFT_PFLOG
751 	case IFT_PFLOG:
752 #endif
753 #ifdef IFT_PFSYNC
754 	case IFT_PFSYNC:
755 #endif
756 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
757 		ND_IFINFO(ifp)->flags |= ND6_IFF_IFDISABLED;
758 		return;
759 	}
760 
761 	/*
762 	 * if link mtu is too small, don't try to configure IPv6.
763 	 * remember there could be some link-layer that has special
764 	 * fragmentation logic.
765 	 */
766 	if (ifp->if_mtu < IPV6_MMTU) {
767 		nd6log((LOG_INFO, "in6_ifattach: "
768 		    "%s has too small MTU, IPv6 not enabled\n",
769 		    if_name(ifp)));
770 		return;
771 	}
772 
773 	/* create a multicast kludge storage (if we have not had one) */
774 	in6_createmkludge(ifp);
775 
776 	/*
777 	 * quirks based on interface type
778 	 */
779 	switch (ifp->if_type) {
780 #ifdef IFT_STF
781 	case IFT_STF:
782 		/*
783 		 * 6to4 interface is a very special kind of beast.
784 		 * no multicast, no linklocal.  RFC2529 specifies how to make
785 		 * linklocals for 6to4 interface, but there's no use and
786 		 * it is rather harmful to have one.
787 		 */
788 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
789 		return;
790 #endif
791 	case IFT_CARP:
792 		return;
793 	default:
794 		break;
795 	}
796 
797 	/*
798 	 * usually, we require multicast capability to the interface
799 	 */
800 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
801 		nd6log((LOG_INFO, "in6_ifattach: "
802 		    "%s is not multicast capable, IPv6 not enabled\n",
803 		    if_name(ifp)));
804 		return;
805 	}
806 
807 	/*
808 	 * assign loopback address for loopback interface.
809 	 * XXX multiple loopback interface case.
810 	 */
811 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
812 		in6 = in6addr_loopback;
813 		if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
814 			if (in6_ifattach_loopback(ifp) != 0)
815 				return;
816 		}
817 	}
818 
819 	/*
820 	 * assign a link-local address, if there's none.
821 	 */
822 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
823 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL)
824 	{
825 		ia = in6ifa_ifpforlinklocal(ifp, 0);
826 		if (ia == NULL && in6_ifattach_linklocal(ifp, altifp) != 0) {
827 			printf("%s: cannot assign link-local address\n",
828 			    ifp->if_xname);
829 		}
830 	}
831 }
832 
833 /*
834  * NOTE: in6_ifdetach() does not support loopback if at this moment.
835  * We don't need this function in bsdi, because interfaces are never removed
836  * from the ifnet list in bsdi.
837  */
838 void
839 in6_ifdetach(struct ifnet *ifp)
840 {
841 	struct in6_ifaddr *ia, *oia;
842 	struct ifaddr *ifa, *next;
843 	struct rtentry *rt;
844 	short rtflags;
845 	struct in6_multi_mship *imm;
846 
847 	/* remove ip6_mrouter stuff */
848 	ip6_mrouter_detach(ifp);
849 
850 	/* remove neighbor management table */
851 	nd6_purge(ifp, NULL);
852 
853 	/* XXX this code is duplicated in in6_purgeif() --dyoung */
854 	/* nuke any of IPv6 addresses we have */
855 	if_purgeaddrs(ifp, AF_INET6, in6_purgeaddr);
856 
857 	/* XXX isn't this code is redundant, given the above? --dyoung */
858 	/* XXX doesn't this code replicate code in in6_purgeaddr() ? --dyoung */
859 	/* undo everything done by in6_ifattach(), just in case */
860 	for (ifa = IFADDR_FIRST(ifp); ifa != NULL; ifa = next) {
861 		next = IFADDR_NEXT(ifa);
862 
863 		if (ifa->ifa_addr->sa_family != AF_INET6
864 		 || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
865 			continue;
866 		}
867 
868 		ia = (struct in6_ifaddr *)ifa;
869 
870 		/*
871 		 * leave from multicast groups we have joined for the interface
872 		 */
873 		while ((imm = LIST_FIRST(&ia->ia6_memberships)) != NULL) {
874 			LIST_REMOVE(imm, i6mm_chain);
875 			in6_leavegroup(imm);
876 		}
877 
878 		/* remove from the routing table */
879 		if ((ia->ia_flags & IFA_ROUTE) &&
880 		    (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0))) {
881 			rtflags = rt->rt_flags;
882 			rtfree(rt);
883 			rtrequest(RTM_DELETE, (struct sockaddr *)&ia->ia_addr,
884 			    (struct sockaddr *)&ia->ia_addr,
885 			    (struct sockaddr *)&ia->ia_prefixmask,
886 			    rtflags, NULL);
887 		}
888 
889 		/* remove from the linked list */
890 		ifa_remove(ifp, &ia->ia_ifa);
891 
892 		/* also remove from the IPv6 address chain(itojun&jinmei) */
893 		oia = ia;
894 		if (oia == (ia = in6_ifaddr))
895 			in6_ifaddr = ia->ia_next;
896 		else {
897 			while (ia->ia_next && (ia->ia_next != oia))
898 				ia = ia->ia_next;
899 			if (ia->ia_next)
900 				ia->ia_next = oia->ia_next;
901 			else {
902 				nd6log((LOG_ERR,
903 				    "%s: didn't unlink in6ifaddr from list\n",
904 				    if_name(ifp)));
905 			}
906 		}
907 
908 		ifafree(&oia->ia_ifa);
909 	}
910 
911 	/* cleanup multicast address kludge table, if there is any */
912 	in6_purgemkludge(ifp);
913 
914 	/*
915 	 * remove neighbor management table.  we call it twice just to make
916 	 * sure we nuke everything.  maybe we need just one call.
917 	 * XXX: since the first call did not release addresses, some prefixes
918 	 * might remain.  We should call nd6_purge() again to release the
919 	 * prefixes after removing all addresses above.
920 	 * (Or can we just delay calling nd6_purge until at this point?)
921 	 */
922 	nd6_purge(ifp, NULL);
923 }
924 
925 int
926 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
927 	const u_int8_t *baseid, int generate)
928 {
929 	u_int8_t nullbuf[8];
930 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
931 
932 	memset(nullbuf, 0, sizeof(nullbuf));
933 	if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
934 		/* we've never created a random ID.  Create a new one. */
935 		generate = 1;
936 	}
937 
938 	if (generate) {
939 		memcpy(ndi->randomseed1, baseid, sizeof(ndi->randomseed1));
940 
941 		/* generate_tmp_ifid will update seedn and buf */
942 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
943 		    ndi->randomid);
944 	}
945 	memcpy(retbuf, ndi->randomid, 8);
946 	if (generate && memcmp(retbuf, nullbuf, sizeof(nullbuf)) == 0) {
947 		/* generate_tmp_ifid could not found a good ID. */
948 		return -1;
949 	}
950 
951 	return 0;
952 }
953 
954 void
955 in6_tmpaddrtimer(void *ignored_arg)
956 {
957 	struct nd_ifinfo *ndi;
958 	u_int8_t nullbuf[8];
959 	struct ifnet *ifp;
960 
961 	mutex_enter(softnet_lock);
962 	KERNEL_LOCK(1, NULL);
963 
964 	callout_reset(&in6_tmpaddrtimer_ch,
965 	    (ip6_temp_preferred_lifetime - ip6_desync_factor -
966 	    ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, NULL);
967 
968 	memset(nullbuf, 0, sizeof(nullbuf));
969 	IFNET_FOREACH(ifp) {
970 		ndi = ND_IFINFO(ifp);
971 		if (memcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
972 			/*
973 			 * We've been generating a random ID on this interface.
974 			 * Create a new one.
975 			 */
976 			(void)generate_tmp_ifid(ndi->randomseed0,
977 			    ndi->randomseed1, ndi->randomid);
978 		}
979 	}
980 
981 	KERNEL_UNLOCK_ONE(NULL);
982 	mutex_exit(softnet_lock);
983 }
984