xref: /freebsd/sys/netinet6/in6_ifattach.c (revision ff0ba87247820afbdfdc1b307c803f7923d0e4d3)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 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: in6_ifattach.c,v 1.118 2001/05/24 07:44:00 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
38 #include <sys/socket.h>
39 #include <sys/sockio.h>
40 #include <sys/jail.h>
41 #include <sys/kernel.h>
42 #include <sys/proc.h>
43 #include <sys/syslog.h>
44 #include <sys/md5.h>
45 
46 #include <net/if.h>
47 #include <net/if_var.h>
48 #include <net/if_dl.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
51 #include <net/vnet.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_var.h>
55 #include <netinet/if_ether.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/udp.h>
59 #include <netinet/udp_var.h>
60 
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet6/in6_var.h>
64 #include <netinet6/in6_pcb.h>
65 #include <netinet6/in6_ifattach.h>
66 #include <netinet6/ip6_var.h>
67 #include <netinet6/nd6.h>
68 #include <netinet6/mld6_var.h>
69 #include <netinet6/scope6_var.h>
70 
71 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
72 
73 #ifdef IP6_AUTO_LINKLOCAL
74 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
75 #else
76 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
77 #endif
78 
79 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
80 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
81 
82 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
83 #define	V_ripcbinfo			VNET(ripcbinfo)
84 
85 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
86 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
87 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
88 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
89 static int in6_ifattach_loopback(struct ifnet *);
90 static void in6_purgemaddrs(struct ifnet *);
91 
92 #define EUI64_GBIT	0x01
93 #define EUI64_UBIT	0x02
94 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
95 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
96 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
97 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
98 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
99 
100 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
101 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
102 
103 /*
104  * Generate a last-resort interface identifier, when the machine has no
105  * IEEE802/EUI64 address sources.
106  * The goal here is to get an interface identifier that is
107  * (1) random enough and (2) does not change across reboot.
108  * We currently use MD5(hostname) for it.
109  *
110  * in6 - upper 64bits are preserved
111  */
112 static int
113 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
114 {
115 	MD5_CTX ctxt;
116 	struct prison *pr;
117 	u_int8_t digest[16];
118 	int hostnamelen;
119 
120 	pr = curthread->td_ucred->cr_prison;
121 	mtx_lock(&pr->pr_mtx);
122 	hostnamelen = strlen(pr->pr_hostname);
123 #if 0
124 	/* we need at least several letters as seed for ifid */
125 	if (hostnamelen < 3) {
126 		mtx_unlock(&pr->pr_mtx);
127 		return -1;
128 	}
129 #endif
130 
131 	/* generate 8 bytes of pseudo-random value. */
132 	bzero(&ctxt, sizeof(ctxt));
133 	MD5Init(&ctxt);
134 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
135 	mtx_unlock(&pr->pr_mtx);
136 	MD5Final(digest, &ctxt);
137 
138 	/* assumes sizeof(digest) > sizeof(ifid) */
139 	bcopy(digest, &in6->s6_addr[8], 8);
140 
141 	/* make sure to set "u" bit to local, and "g" bit to individual. */
142 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
143 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
144 
145 	/* convert EUI64 into IPv6 interface identifier */
146 	EUI64_TO_IFID(in6);
147 
148 	return 0;
149 }
150 
151 static int
152 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
153 {
154 	MD5_CTX ctxt;
155 	u_int8_t seed[16], digest[16], nullbuf[8];
156 	u_int32_t val32;
157 
158 	/* If there's no history, start with a random seed. */
159 	bzero(nullbuf, sizeof(nullbuf));
160 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
161 		int i;
162 
163 		for (i = 0; i < 2; i++) {
164 			val32 = arc4random();
165 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
166 		}
167 	} else
168 		bcopy(seed0, seed, 8);
169 
170 	/* copy the right-most 64-bits of the given address */
171 	/* XXX assumption on the size of IFID */
172 	bcopy(seed1, &seed[8], 8);
173 
174 	if (0) {		/* for debugging purposes only */
175 		int i;
176 
177 		printf("generate_tmp_ifid: new randomized ID from: ");
178 		for (i = 0; i < 16; i++)
179 			printf("%02x", seed[i]);
180 		printf(" ");
181 	}
182 
183 	/* generate 16 bytes of pseudo-random value. */
184 	bzero(&ctxt, sizeof(ctxt));
185 	MD5Init(&ctxt);
186 	MD5Update(&ctxt, seed, sizeof(seed));
187 	MD5Final(digest, &ctxt);
188 
189 	/*
190 	 * RFC 3041 3.2.1. (3)
191 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
192 	 * left-most bit is numbered 0) to zero.
193 	 */
194 	bcopy(digest, ret, 8);
195 	ret[0] &= ~EUI64_UBIT;
196 
197 	/*
198 	 * XXX: we'd like to ensure that the generated value is not zero
199 	 * for simplicity.  If the caclculated digest happens to be zero,
200 	 * use a random non-zero value as the last resort.
201 	 */
202 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
203 		nd6log((LOG_INFO,
204 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
205 
206 		val32 = arc4random();
207 		val32 = 1 + (val32 % (0xffffffff - 1));
208 	}
209 
210 	/*
211 	 * RFC 3041 3.2.1. (4)
212 	 * Take the rightmost 64-bits of the MD5 digest and save them in
213 	 * stable storage as the history value to be used in the next
214 	 * iteration of the algorithm.
215 	 */
216 	bcopy(&digest[8], seed0, 8);
217 
218 	if (0) {		/* for debugging purposes only */
219 		int i;
220 
221 		printf("to: ");
222 		for (i = 0; i < 16; i++)
223 			printf("%02x", digest[i]);
224 		printf("\n");
225 	}
226 
227 	return 0;
228 }
229 
230 /*
231  * Get interface identifier for the specified interface.
232  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
233  *
234  * in6 - upper 64bits are preserved
235  */
236 int
237 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
238 {
239 	struct ifaddr *ifa;
240 	struct sockaddr_dl *sdl;
241 	u_int8_t *addr;
242 	size_t addrlen;
243 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
244 	static u_int8_t allone[8] =
245 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
246 
247 	IF_ADDR_RLOCK(ifp);
248 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
249 		if (ifa->ifa_addr->sa_family != AF_LINK)
250 			continue;
251 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
252 		if (sdl == NULL)
253 			continue;
254 		if (sdl->sdl_alen == 0)
255 			continue;
256 
257 		goto found;
258 	}
259 	IF_ADDR_RUNLOCK(ifp);
260 
261 	return -1;
262 
263 found:
264 	IF_ADDR_LOCK_ASSERT(ifp);
265 	addr = LLADDR(sdl);
266 	addrlen = sdl->sdl_alen;
267 
268 	/* get EUI64 */
269 	switch (ifp->if_type) {
270 	case IFT_BRIDGE:
271 	case IFT_ETHER:
272 	case IFT_L2VLAN:
273 	case IFT_FDDI:
274 	case IFT_ISO88025:
275 	case IFT_ATM:
276 	case IFT_IEEE1394:
277 #ifdef IFT_IEEE80211
278 	case IFT_IEEE80211:
279 #endif
280 		/* IEEE802/EUI64 cases - what others? */
281 		/* IEEE1394 uses 16byte length address starting with EUI64 */
282 		if (addrlen > 8)
283 			addrlen = 8;
284 
285 		/* look at IEEE802/EUI64 only */
286 		if (addrlen != 8 && addrlen != 6) {
287 			IF_ADDR_RUNLOCK(ifp);
288 			return -1;
289 		}
290 
291 		/*
292 		 * check for invalid MAC address - on bsdi, we see it a lot
293 		 * since wildboar configures all-zero MAC on pccard before
294 		 * card insertion.
295 		 */
296 		if (bcmp(addr, allzero, addrlen) == 0) {
297 			IF_ADDR_RUNLOCK(ifp);
298 			return -1;
299 		}
300 		if (bcmp(addr, allone, addrlen) == 0) {
301 			IF_ADDR_RUNLOCK(ifp);
302 			return -1;
303 		}
304 
305 		/* make EUI64 address */
306 		if (addrlen == 8)
307 			bcopy(addr, &in6->s6_addr[8], 8);
308 		else if (addrlen == 6) {
309 			in6->s6_addr[8] = addr[0];
310 			in6->s6_addr[9] = addr[1];
311 			in6->s6_addr[10] = addr[2];
312 			in6->s6_addr[11] = 0xff;
313 			in6->s6_addr[12] = 0xfe;
314 			in6->s6_addr[13] = addr[3];
315 			in6->s6_addr[14] = addr[4];
316 			in6->s6_addr[15] = addr[5];
317 		}
318 		break;
319 
320 	case IFT_ARCNET:
321 		if (addrlen != 1) {
322 			IF_ADDR_RUNLOCK(ifp);
323 			return -1;
324 		}
325 		if (!addr[0]) {
326 			IF_ADDR_RUNLOCK(ifp);
327 			return -1;
328 		}
329 
330 		bzero(&in6->s6_addr[8], 8);
331 		in6->s6_addr[15] = addr[0];
332 
333 		/*
334 		 * due to insufficient bitwidth, we mark it local.
335 		 */
336 		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
337 		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
338 		break;
339 
340 	case IFT_GIF:
341 #ifdef IFT_STF
342 	case IFT_STF:
343 #endif
344 		/*
345 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
346 		 * however, IPv4 address is not very suitable as unique
347 		 * identifier source (can be renumbered).
348 		 * we don't do this.
349 		 */
350 		IF_ADDR_RUNLOCK(ifp);
351 		return -1;
352 
353 	default:
354 		IF_ADDR_RUNLOCK(ifp);
355 		return -1;
356 	}
357 
358 	/* sanity check: g bit must not indicate "group" */
359 	if (EUI64_GROUP(in6)) {
360 		IF_ADDR_RUNLOCK(ifp);
361 		return -1;
362 	}
363 
364 	/* convert EUI64 into IPv6 interface identifier */
365 	EUI64_TO_IFID(in6);
366 
367 	/*
368 	 * sanity check: ifid must not be all zero, avoid conflict with
369 	 * subnet router anycast
370 	 */
371 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
372 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
373 		IF_ADDR_RUNLOCK(ifp);
374 		return -1;
375 	}
376 
377 	IF_ADDR_RUNLOCK(ifp);
378 	return 0;
379 }
380 
381 /*
382  * Get interface identifier for the specified interface.  If it is not
383  * available on ifp0, borrow interface identifier from other information
384  * sources.
385  *
386  * altifp - secondary EUI64 source
387  */
388 static int
389 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
390     struct in6_addr *in6)
391 {
392 	struct ifnet *ifp;
393 
394 	/* first, try to get it from the interface itself */
395 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
396 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
397 		    if_name(ifp0)));
398 		goto success;
399 	}
400 
401 	/* try secondary EUI64 source. this basically is for ATM PVC */
402 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
403 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
404 		    if_name(ifp0), if_name(altifp)));
405 		goto success;
406 	}
407 
408 	/* next, try to get it from some other hardware interface */
409 	IFNET_RLOCK_NOSLEEP();
410 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
411 		if (ifp == ifp0)
412 			continue;
413 		if (in6_get_hw_ifid(ifp, in6) != 0)
414 			continue;
415 
416 		/*
417 		 * to borrow ifid from other interface, ifid needs to be
418 		 * globally unique
419 		 */
420 		if (IFID_UNIVERSAL(in6)) {
421 			nd6log((LOG_DEBUG,
422 			    "%s: borrow interface identifier from %s\n",
423 			    if_name(ifp0), if_name(ifp)));
424 			IFNET_RUNLOCK_NOSLEEP();
425 			goto success;
426 		}
427 	}
428 	IFNET_RUNLOCK_NOSLEEP();
429 
430 	/* last resort: get from random number source */
431 	if (get_rand_ifid(ifp, in6) == 0) {
432 		nd6log((LOG_DEBUG,
433 		    "%s: interface identifier generated by random number\n",
434 		    if_name(ifp0)));
435 		goto success;
436 	}
437 
438 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
439 	return -1;
440 
441 success:
442 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
443 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
444 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
445 	    in6->s6_addr[14], in6->s6_addr[15]));
446 	return 0;
447 }
448 
449 /*
450  * altifp - secondary EUI64 source
451  */
452 static int
453 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
454 {
455 	struct in6_ifaddr *ia;
456 	struct in6_aliasreq ifra;
457 	struct nd_prefixctl pr0;
458 	int error;
459 
460 	/*
461 	 * configure link-local address.
462 	 */
463 	in6_prepare_ifra(&ifra, NULL, &in6mask64);
464 
465 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
466 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
467 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
468 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
469 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
470 	} else {
471 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
472 			nd6log((LOG_ERR,
473 			    "%s: no ifid available\n", if_name(ifp)));
474 			return (-1);
475 		}
476 	}
477 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
478 		return (-1);
479 
480 	/* link-local addresses should NEVER expire. */
481 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
482 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
483 
484 	/*
485 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
486 	 * a link-local address. We can set the 3rd argument to NULL, because
487 	 * we know there's no other link-local address on the interface
488 	 * and therefore we are adding one (instead of updating one).
489 	 */
490 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
491 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
492 		/*
493 		 * XXX: When the interface does not support IPv6, this call
494 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
495 		 * notification is rather confusing in this case, so just
496 		 * suppress it.  (jinmei@kame.net 20010130)
497 		 */
498 		if (error != EAFNOSUPPORT)
499 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
500 			    "configure a link-local address on %s "
501 			    "(errno=%d)\n",
502 			    if_name(ifp), error));
503 		return (-1);
504 	}
505 
506 	ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
507 	KASSERT(ia != NULL, ("%s: ia == NULL, ifp=%p", __func__, ifp));
508 
509 	ifa_free(&ia->ia_ifa);
510 
511 	/*
512 	 * Make the link-local prefix (fe80::%link/64) as on-link.
513 	 * Since we'd like to manage prefixes separately from addresses,
514 	 * we make an ND6 prefix structure for the link-local prefix,
515 	 * and add it to the prefix list as a never-expire prefix.
516 	 * XXX: this change might affect some existing code base...
517 	 */
518 	bzero(&pr0, sizeof(pr0));
519 	pr0.ndpr_ifp = ifp;
520 	/* this should be 64 at this moment. */
521 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
522 	pr0.ndpr_prefix = ifra.ifra_addr;
523 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
524 	IN6_MASK_ADDR(&pr0.ndpr_prefix.sin6_addr, &in6mask64);
525 	/*
526 	 * Initialize parameters.  The link-local prefix must always be
527 	 * on-link, and its lifetimes never expire.
528 	 */
529 	pr0.ndpr_raf_onlink = 1;
530 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
531 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
532 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
533 	/*
534 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
535 	 * probably returns NULL.  However, we cannot always expect the result.
536 	 * For example, if we first remove the (only) existing link-local
537 	 * address, and then reconfigure another one, the prefix is still
538 	 * valid with referring to the old link-local address.
539 	 */
540 	if (nd6_prefix_lookup(&pr0) == NULL) {
541 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
542 			return (error);
543 	}
544 
545 	return 0;
546 }
547 
548 /*
549  * ifp - must be IFT_LOOP
550  */
551 static int
552 in6_ifattach_loopback(struct ifnet *ifp)
553 {
554 	struct in6_aliasreq ifra;
555 	int error;
556 
557 	in6_prepare_ifra(&ifra, &in6addr_loopback, &in6mask128);
558 
559 	/*
560 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
561 	 * address.  Follows IPv4 practice - see in_ifinit().
562 	 */
563 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
564 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
565 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
566 
567 	/* the loopback  address should NEVER expire. */
568 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
569 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
570 
571 	/* we don't need to perform DAD on loopback interfaces. */
572 	ifra.ifra_flags |= IN6_IFF_NODAD;
573 
574 	/* skip registration to the prefix list. XXX should be temporary. */
575 	ifra.ifra_flags |= IN6_IFF_NOPFX;
576 
577 	/*
578 	 * We are sure that this is a newly assigned address, so we can set
579 	 * NULL to the 3rd arg.
580 	 */
581 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
582 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
583 		    "the loopback address on %s (errno=%d)\n",
584 		    if_name(ifp), error));
585 		return (-1);
586 	}
587 
588 	return 0;
589 }
590 
591 /*
592  * compute NI group address, based on the current hostname setting.
593  * see RFC 4620.
594  *
595  * when ifp == NULL, the caller is responsible for filling scopeid.
596  *
597  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
598  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
599  */
600 static int
601 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
602     struct in6_addr *in6, int oldmcprefix)
603 {
604 	struct prison *pr;
605 	const char *p;
606 	u_char *q;
607 	MD5_CTX ctxt;
608 	u_int8_t digest[16];
609 	char l;
610 	char n[64];	/* a single label must not exceed 63 chars */
611 
612 	/*
613 	 * If no name is given and namelen is -1,
614 	 * we try to do the hostname lookup ourselves.
615 	 */
616 	if (!name && namelen == -1) {
617 		pr = curthread->td_ucred->cr_prison;
618 		mtx_lock(&pr->pr_mtx);
619 		name = pr->pr_hostname;
620 		namelen = strlen(name);
621 	} else
622 		pr = NULL;
623 	if (!name || !namelen) {
624 		if (pr != NULL)
625 			mtx_unlock(&pr->pr_mtx);
626 		return -1;
627 	}
628 
629 	p = name;
630 	while (p && *p && *p != '.' && p - name < namelen)
631 		p++;
632 	if (p == name || p - name > sizeof(n) - 1) {
633 		if (pr != NULL)
634 			mtx_unlock(&pr->pr_mtx);
635 		return -1;	/* label too long */
636 	}
637 	l = p - name;
638 	strncpy(n, name, l);
639 	if (pr != NULL)
640 		mtx_unlock(&pr->pr_mtx);
641 	n[(int)l] = '\0';
642 	for (q = n; *q; q++) {
643 		if ('A' <= *q && *q <= 'Z')
644 			*q = *q - 'A' + 'a';
645 	}
646 
647 	/* generate 16 bytes of pseudo-random value. */
648 	bzero(&ctxt, sizeof(ctxt));
649 	MD5Init(&ctxt);
650 	MD5Update(&ctxt, &l, sizeof(l));
651 	MD5Update(&ctxt, n, l);
652 	MD5Final(digest, &ctxt);
653 
654 	bzero(in6, sizeof(*in6));
655 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
656 	in6->s6_addr8[11] = 2;
657 	if (oldmcprefix == 0) {
658 		in6->s6_addr8[12] = 0xff;
659 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
660 		bcopy(digest, &in6->s6_addr8[13], 3);
661 	} else {
662 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
663 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
664 	}
665 	if (in6_setscope(in6, ifp, NULL))
666 		return (-1); /* XXX: should not fail */
667 
668 	return 0;
669 }
670 
671 int
672 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
673     struct in6_addr *in6)
674 {
675 
676 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
677 }
678 
679 int
680 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
681     struct in6_addr *in6)
682 {
683 
684 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
685 }
686 
687 /*
688  * XXX multiple loopback interface needs more care.  for instance,
689  * nodelocal address needs to be configured onto only one of them.
690  * XXX multiple link-local address case
691  *
692  * altifp - secondary EUI64 source
693  */
694 void
695 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
696 {
697 	struct in6_ifaddr *ia;
698 	struct in6_addr in6;
699 
700 	if (ifp->if_afdata[AF_INET6] == NULL)
701 		return;
702 	/*
703 	 * quirks based on interface type
704 	 */
705 	switch (ifp->if_type) {
706 	case IFT_STF:
707 		/*
708 		 * 6to4 interface is a very special kind of beast.
709 		 * no multicast, no linklocal.  RFC2529 specifies how to make
710 		 * linklocals for 6to4 interface, but there's no use and
711 		 * it is rather harmful to have one.
712 		 */
713 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
714 		break;
715 	default:
716 		break;
717 	}
718 
719 	/*
720 	 * usually, we require multicast capability to the interface
721 	 */
722 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
723 		nd6log((LOG_INFO, "in6_ifattach: "
724 		    "%s is not multicast capable, IPv6 not enabled\n",
725 		    if_name(ifp)));
726 		return;
727 	}
728 
729 	/*
730 	 * assign loopback address for loopback interface.
731 	 * XXX multiple loopback interface case.
732 	 */
733 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
734 		struct ifaddr *ifa;
735 
736 		in6 = in6addr_loopback;
737 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &in6);
738 		if (ifa == NULL) {
739 			if (in6_ifattach_loopback(ifp) != 0)
740 				return;
741 		} else
742 			ifa_free(ifa);
743 	}
744 
745 	/*
746 	 * assign a link-local address, if there's none.
747 	 */
748 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
749 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
750 		int error;
751 
752 		ia = in6ifa_ifpforlinklocal(ifp, 0);
753 		if (ia == NULL) {
754 			error = in6_ifattach_linklocal(ifp, altifp);
755 #if 0
756 			if (error)
757 				log(LOG_NOTICE, "in6_ifattach_linklocal: "
758 				    "failed to add a link-local addr to %s\n",
759 				    if_name(ifp));
760 #endif
761 		} else
762 			ifa_free(&ia->ia_ifa);
763 	}
764 
765 	/* update dynamically. */
766 	if (V_in6_maxmtu < ifp->if_mtu)
767 		V_in6_maxmtu = ifp->if_mtu;
768 }
769 
770 /*
771  * NOTE: in6_ifdetach() does not support loopback if at this moment.
772  * We don't need this function in bsdi, because interfaces are never removed
773  * from the ifnet list in bsdi.
774  */
775 void
776 in6_ifdetach(struct ifnet *ifp)
777 {
778 	struct ifaddr *ifa, *next;
779 
780 	if (ifp->if_afdata[AF_INET6] == NULL)
781 		return;
782 
783 	/* remove neighbor management table */
784 	nd6_purge(ifp);
785 
786 	/*
787 	 * nuke any of IPv6 addresses we have
788 	 * XXX: all addresses should be already removed
789 	 */
790 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
791 		if (ifa->ifa_addr->sa_family != AF_INET6)
792 			continue;
793 		in6_purgeaddr(ifa);
794 	}
795 	in6_pcbpurgeif0(&V_udbinfo, ifp);
796 	in6_pcbpurgeif0(&V_ulitecbinfo, ifp);
797 	in6_pcbpurgeif0(&V_ripcbinfo, ifp);
798 	/* leave from all multicast groups joined */
799 	in6_purgemaddrs(ifp);
800 
801 	/*
802 	 * remove neighbor management table.  we call it twice just to make
803 	 * sure we nuke everything.  maybe we need just one call.
804 	 * XXX: since the first call did not release addresses, some prefixes
805 	 * might remain.  We should call nd6_purge() again to release the
806 	 * prefixes after removing all addresses above.
807 	 * (Or can we just delay calling nd6_purge until at this point?)
808 	 */
809 	nd6_purge(ifp);
810 }
811 
812 int
813 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
814     const u_int8_t *baseid, int generate)
815 {
816 	u_int8_t nullbuf[8];
817 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
818 
819 	bzero(nullbuf, sizeof(nullbuf));
820 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
821 		/* we've never created a random ID.  Create a new one. */
822 		generate = 1;
823 	}
824 
825 	if (generate) {
826 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
827 
828 		/* generate_tmp_ifid will update seedn and buf */
829 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
830 		    ndi->randomid);
831 	}
832 	bcopy(ndi->randomid, retbuf, 8);
833 
834 	return (0);
835 }
836 
837 void
838 in6_tmpaddrtimer(void *arg)
839 {
840 	CURVNET_SET((struct vnet *) arg);
841 	struct nd_ifinfo *ndi;
842 	u_int8_t nullbuf[8];
843 	struct ifnet *ifp;
844 
845 	callout_reset(&V_in6_tmpaddrtimer_ch,
846 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
847 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
848 
849 	bzero(nullbuf, sizeof(nullbuf));
850 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
851 		if (ifp->if_afdata[AF_INET6] == NULL)
852 			continue;
853 		ndi = ND_IFINFO(ifp);
854 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
855 			/*
856 			 * We've been generating a random ID on this interface.
857 			 * Create a new one.
858 			 */
859 			(void)generate_tmp_ifid(ndi->randomseed0,
860 			    ndi->randomseed1, ndi->randomid);
861 		}
862 	}
863 
864 	CURVNET_RESTORE();
865 }
866 
867 static void
868 in6_purgemaddrs(struct ifnet *ifp)
869 {
870 	LIST_HEAD(,in6_multi)	 purgeinms;
871 	struct in6_multi	*inm, *tinm;
872 	struct ifmultiaddr	*ifma;
873 
874 	LIST_INIT(&purgeinms);
875 	IN6_MULTI_LOCK();
876 
877 	/*
878 	 * Extract list of in6_multi associated with the detaching ifp
879 	 * which the PF_INET6 layer is about to release.
880 	 * We need to do this as IF_ADDR_LOCK() may be re-acquired
881 	 * by code further down.
882 	 */
883 	IF_ADDR_RLOCK(ifp);
884 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
885 		if (ifma->ifma_addr->sa_family != AF_INET6 ||
886 		    ifma->ifma_protospec == NULL)
887 			continue;
888 		inm = (struct in6_multi *)ifma->ifma_protospec;
889 		LIST_INSERT_HEAD(&purgeinms, inm, in6m_entry);
890 	}
891 	IF_ADDR_RUNLOCK(ifp);
892 
893 	LIST_FOREACH_SAFE(inm, &purgeinms, in6m_entry, tinm) {
894 		LIST_REMOVE(inm, in6m_entry);
895 		in6m_release_locked(inm);
896 	}
897 	mld_ifdetach(ifp);
898 
899 	IN6_MULTI_UNLOCK();
900 }
901