xref: /freebsd/sys/netinet6/in6_ifattach.c (revision a0b9e2e854027e6ff61fb075a1309dbc71c42b54)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 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: in6_ifattach.c,v 1.118 2001/05/24 07:44:00 itojun Exp $
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/jail.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/proc.h>
46 #include <sys/rmlock.h>
47 #include <sys/syslog.h>
48 #include <sys/md5.h>
49 
50 #include <net/if.h>
51 #include <net/if_var.h>
52 #include <net/if_dl.h>
53 #include <net/if_types.h>
54 #include <net/route.h>
55 #include <net/vnet.h>
56 
57 #include <netinet/in.h>
58 #include <netinet/in_var.h>
59 #include <netinet/if_ether.h>
60 #include <netinet/in_pcb.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/udp.h>
63 #include <netinet/udp_var.h>
64 
65 #include <netinet/ip6.h>
66 #include <netinet6/ip6_var.h>
67 #include <netinet6/in6_var.h>
68 #include <netinet6/in6_pcb.h>
69 #include <netinet6/in6_ifattach.h>
70 #include <netinet6/ip6_var.h>
71 #include <netinet6/nd6.h>
72 #include <netinet6/mld6_var.h>
73 #include <netinet6/scope6_var.h>
74 
75 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
76 
77 #ifdef IP6_AUTO_LINKLOCAL
78 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
79 #else
80 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
81 #endif
82 
83 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
84 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
85 
86 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
87 #define	V_ripcbinfo			VNET(ripcbinfo)
88 
89 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
90 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
91 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
92 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
93 static int in6_ifattach_loopback(struct ifnet *);
94 static void in6_purgemaddrs(struct ifnet *);
95 
96 #define EUI64_GBIT	0x01
97 #define EUI64_UBIT	0x02
98 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
99 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
100 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
101 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
102 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
103 
104 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
105 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
106 
107 /*
108  * Generate a last-resort interface identifier, when the machine has no
109  * IEEE802/EUI64 address sources.
110  * The goal here is to get an interface identifier that is
111  * (1) random enough and (2) does not change across reboot.
112  * We currently use MD5(hostname) for it.
113  *
114  * in6 - upper 64bits are preserved
115  */
116 static int
117 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
118 {
119 	MD5_CTX ctxt;
120 	struct prison *pr;
121 	u_int8_t digest[16];
122 	int hostnamelen;
123 
124 	pr = curthread->td_ucred->cr_prison;
125 	mtx_lock(&pr->pr_mtx);
126 	hostnamelen = strlen(pr->pr_hostname);
127 #if 0
128 	/* we need at least several letters as seed for ifid */
129 	if (hostnamelen < 3) {
130 		mtx_unlock(&pr->pr_mtx);
131 		return -1;
132 	}
133 #endif
134 
135 	/* generate 8 bytes of pseudo-random value. */
136 	bzero(&ctxt, sizeof(ctxt));
137 	MD5Init(&ctxt);
138 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
139 	mtx_unlock(&pr->pr_mtx);
140 	MD5Final(digest, &ctxt);
141 
142 	/* assumes sizeof(digest) > sizeof(ifid) */
143 	bcopy(digest, &in6->s6_addr[8], 8);
144 
145 	/* make sure to set "u" bit to local, and "g" bit to individual. */
146 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
147 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
148 
149 	/* convert EUI64 into IPv6 interface identifier */
150 	EUI64_TO_IFID(in6);
151 
152 	return 0;
153 }
154 
155 static int
156 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
157 {
158 	MD5_CTX ctxt;
159 	u_int8_t seed[16], digest[16], nullbuf[8];
160 	u_int32_t val32;
161 
162 	/* If there's no history, start with a random seed. */
163 	bzero(nullbuf, sizeof(nullbuf));
164 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
165 		int i;
166 
167 		for (i = 0; i < 2; i++) {
168 			val32 = arc4random();
169 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
170 		}
171 	} else
172 		bcopy(seed0, seed, 8);
173 
174 	/* copy the right-most 64-bits of the given address */
175 	/* XXX assumption on the size of IFID */
176 	bcopy(seed1, &seed[8], 8);
177 
178 	if (0) {		/* for debugging purposes only */
179 		int i;
180 
181 		printf("generate_tmp_ifid: new randomized ID from: ");
182 		for (i = 0; i < 16; i++)
183 			printf("%02x", seed[i]);
184 		printf(" ");
185 	}
186 
187 	/* generate 16 bytes of pseudo-random value. */
188 	bzero(&ctxt, sizeof(ctxt));
189 	MD5Init(&ctxt);
190 	MD5Update(&ctxt, seed, sizeof(seed));
191 	MD5Final(digest, &ctxt);
192 
193 	/*
194 	 * RFC 3041 3.2.1. (3)
195 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
196 	 * left-most bit is numbered 0) to zero.
197 	 */
198 	bcopy(digest, ret, 8);
199 	ret[0] &= ~EUI64_UBIT;
200 
201 	/*
202 	 * XXX: we'd like to ensure that the generated value is not zero
203 	 * for simplicity.  If the caclculated digest happens to be zero,
204 	 * use a random non-zero value as the last resort.
205 	 */
206 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
207 		nd6log((LOG_INFO,
208 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
209 
210 		val32 = arc4random();
211 		val32 = 1 + (val32 % (0xffffffff - 1));
212 	}
213 
214 	/*
215 	 * RFC 3041 3.2.1. (4)
216 	 * Take the rightmost 64-bits of the MD5 digest and save them in
217 	 * stable storage as the history value to be used in the next
218 	 * iteration of the algorithm.
219 	 */
220 	bcopy(&digest[8], seed0, 8);
221 
222 	if (0) {		/* for debugging purposes only */
223 		int i;
224 
225 		printf("to: ");
226 		for (i = 0; i < 16; i++)
227 			printf("%02x", digest[i]);
228 		printf("\n");
229 	}
230 
231 	return 0;
232 }
233 
234 /*
235  * Get interface identifier for the specified interface.
236  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
237  *
238  * in6 - upper 64bits are preserved
239  */
240 int
241 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
242 {
243 	struct ifaddr *ifa;
244 	struct sockaddr_dl *sdl;
245 	u_int8_t *addr;
246 	size_t addrlen;
247 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
248 	static u_int8_t allone[8] =
249 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
250 
251 	NET_EPOCH_ASSERT();
252 
253 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
254 		if (ifa->ifa_addr->sa_family != AF_LINK)
255 			continue;
256 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
257 		if (sdl == NULL)
258 			continue;
259 		if (sdl->sdl_alen == 0)
260 			continue;
261 
262 		goto found;
263 	}
264 
265 	return -1;
266 
267 found:
268 	addr = LLADDR(sdl);
269 	addrlen = sdl->sdl_alen;
270 
271 	/* get EUI64 */
272 	switch (ifp->if_type) {
273 	case IFT_BRIDGE:
274 	case IFT_ETHER:
275 	case IFT_L2VLAN:
276 	case IFT_ATM:
277 	case IFT_IEEE1394:
278 		/* IEEE802/EUI64 cases - what others? */
279 		/* IEEE1394 uses 16byte length address starting with EUI64 */
280 		if (addrlen > 8)
281 			addrlen = 8;
282 
283 		/* look at IEEE802/EUI64 only */
284 		if (addrlen != 8 && addrlen != 6)
285 			return -1;
286 
287 		/*
288 		 * check for invalid MAC address - on bsdi, we see it a lot
289 		 * since wildboar configures all-zero MAC on pccard before
290 		 * card insertion.
291 		 */
292 		if (bcmp(addr, allzero, addrlen) == 0)
293 			return -1;
294 		if (bcmp(addr, allone, addrlen) == 0)
295 			return -1;
296 
297 		/* make EUI64 address */
298 		if (addrlen == 8)
299 			bcopy(addr, &in6->s6_addr[8], 8);
300 		else if (addrlen == 6) {
301 			in6->s6_addr[8] = addr[0];
302 			in6->s6_addr[9] = addr[1];
303 			in6->s6_addr[10] = addr[2];
304 			in6->s6_addr[11] = 0xff;
305 			in6->s6_addr[12] = 0xfe;
306 			in6->s6_addr[13] = addr[3];
307 			in6->s6_addr[14] = addr[4];
308 			in6->s6_addr[15] = addr[5];
309 		}
310 		break;
311 
312 	case IFT_GIF:
313 	case IFT_STF:
314 		/*
315 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
316 		 * however, IPv4 address is not very suitable as unique
317 		 * identifier source (can be renumbered).
318 		 * we don't do this.
319 		 */
320 		return -1;
321 
322 	case IFT_INFINIBAND:
323 		if (addrlen != 20)
324 			return -1;
325 		bcopy(addr + 12, &in6->s6_addr[8], 8);
326 		break;
327 
328 	default:
329 		return -1;
330 	}
331 
332 	/* sanity check: g bit must not indicate "group" */
333 	if (EUI64_GROUP(in6))
334 		return -1;
335 
336 	/* convert EUI64 into IPv6 interface identifier */
337 	EUI64_TO_IFID(in6);
338 
339 	/*
340 	 * sanity check: ifid must not be all zero, avoid conflict with
341 	 * subnet router anycast
342 	 */
343 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
344 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0)
345 		return -1;
346 
347 	return 0;
348 }
349 
350 /*
351  * Get interface identifier for the specified interface.  If it is not
352  * available on ifp0, borrow interface identifier from other information
353  * sources.
354  *
355  * altifp - secondary EUI64 source
356  */
357 static int
358 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
359     struct in6_addr *in6)
360 {
361 	struct ifnet *ifp;
362 
363 	NET_EPOCH_ASSERT();
364 
365 	/* first, try to get it from the interface itself */
366 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
367 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
368 		    if_name(ifp0)));
369 		goto success;
370 	}
371 
372 	/* try secondary EUI64 source. this basically is for ATM PVC */
373 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
374 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
375 		    if_name(ifp0), if_name(altifp)));
376 		goto success;
377 	}
378 
379 	/* next, try to get it from some other hardware interface */
380 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
381 		if (ifp == ifp0)
382 			continue;
383 		if (in6_get_hw_ifid(ifp, in6) != 0)
384 			continue;
385 
386 		/*
387 		 * to borrow ifid from other interface, ifid needs to be
388 		 * globally unique
389 		 */
390 		if (IFID_UNIVERSAL(in6)) {
391 			nd6log((LOG_DEBUG,
392 			    "%s: borrow interface identifier from %s\n",
393 			    if_name(ifp0), if_name(ifp)));
394 			goto success;
395 		}
396 	}
397 
398 	/* last resort: get from random number source */
399 	if (get_rand_ifid(ifp, in6) == 0) {
400 		nd6log((LOG_DEBUG,
401 		    "%s: interface identifier generated by random number\n",
402 		    if_name(ifp0)));
403 		goto success;
404 	}
405 
406 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
407 	return -1;
408 
409 success:
410 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
411 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
412 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
413 	    in6->s6_addr[14], in6->s6_addr[15]));
414 	return 0;
415 }
416 
417 /*
418  * altifp - secondary EUI64 source
419  */
420 static int
421 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
422 {
423 	struct in6_ifaddr *ia;
424 	struct in6_aliasreq ifra;
425 	struct nd_prefixctl pr0;
426 	struct epoch_tracker et;
427 	struct nd_prefix *pr;
428 	int error;
429 
430 	/*
431 	 * configure link-local address.
432 	 */
433 	in6_prepare_ifra(&ifra, NULL, &in6mask64);
434 
435 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
436 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
437 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
438 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
439 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
440 	} else {
441 		NET_EPOCH_ENTER(et);
442 		error = get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr);
443 		NET_EPOCH_EXIT(et);
444 		if (error != 0) {
445 			nd6log((LOG_ERR,
446 			    "%s: no ifid available\n", if_name(ifp)));
447 			return (-1);
448 		}
449 	}
450 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
451 		return (-1);
452 
453 	/* link-local addresses should NEVER expire. */
454 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
455 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
456 
457 	/*
458 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
459 	 * a link-local address. We can set the 3rd argument to NULL, because
460 	 * we know there's no other link-local address on the interface
461 	 * and therefore we are adding one (instead of updating one).
462 	 */
463 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
464 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
465 		/*
466 		 * XXX: When the interface does not support IPv6, this call
467 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
468 		 * notification is rather confusing in this case, so just
469 		 * suppress it.  (jinmei@kame.net 20010130)
470 		 */
471 		if (error != EAFNOSUPPORT)
472 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
473 			    "configure a link-local address on %s "
474 			    "(errno=%d)\n",
475 			    if_name(ifp), error));
476 		return (-1);
477 	}
478 
479 	NET_EPOCH_ENTER(et);
480 	ia = in6ifa_ifpforlinklocal(ifp, 0);
481 	NET_EPOCH_EXIT(et);
482 	if (ia == NULL) {
483 		/*
484 		 * Another thread removed the address that we just added.
485 		 * This should be rare, but it happens.
486 		 */
487 		nd6log((LOG_NOTICE, "%s: %s: new link-local address "
488 			"disappeared\n", __func__, if_name(ifp)));
489 		return (-1);
490 	}
491 	ifa_free(&ia->ia_ifa);
492 
493 	/*
494 	 * Make the link-local prefix (fe80::%link/64) as on-link.
495 	 * Since we'd like to manage prefixes separately from addresses,
496 	 * we make an ND6 prefix structure for the link-local prefix,
497 	 * and add it to the prefix list as a never-expire prefix.
498 	 * XXX: this change might affect some existing code base...
499 	 */
500 	bzero(&pr0, sizeof(pr0));
501 	pr0.ndpr_ifp = ifp;
502 	/* this should be 64 at this moment. */
503 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
504 	pr0.ndpr_prefix = ifra.ifra_addr;
505 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
506 	IN6_MASK_ADDR(&pr0.ndpr_prefix.sin6_addr, &in6mask64);
507 	/*
508 	 * Initialize parameters.  The link-local prefix must always be
509 	 * on-link, and its lifetimes never expire.
510 	 */
511 	pr0.ndpr_raf_onlink = 1;
512 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
513 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
514 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
515 	/*
516 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
517 	 * probably returns NULL.  However, we cannot always expect the result.
518 	 * For example, if we first remove the (only) existing link-local
519 	 * address, and then reconfigure another one, the prefix is still
520 	 * valid with referring to the old link-local address.
521 	 */
522 	if ((pr = nd6_prefix_lookup(&pr0)) == NULL) {
523 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
524 			return (error);
525 	} else
526 		nd6_prefix_rele(pr);
527 
528 	return 0;
529 }
530 
531 /*
532  * ifp - must be IFT_LOOP
533  */
534 static int
535 in6_ifattach_loopback(struct ifnet *ifp)
536 {
537 	struct in6_aliasreq ifra;
538 	int error;
539 
540 	in6_prepare_ifra(&ifra, &in6addr_loopback, &in6mask128);
541 
542 	/*
543 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
544 	 * address.  Follows IPv4 practice - see in_ifinit().
545 	 */
546 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
547 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
548 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
549 
550 	/* the loopback  address should NEVER expire. */
551 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
552 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
553 
554 	/*
555 	 * We are sure that this is a newly assigned address, so we can set
556 	 * NULL to the 3rd arg.
557 	 */
558 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
559 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
560 		    "the loopback address on %s (errno=%d)\n",
561 		    if_name(ifp), error));
562 		return (-1);
563 	}
564 
565 	return 0;
566 }
567 
568 /*
569  * compute NI group address, based on the current hostname setting.
570  * see RFC 4620.
571  *
572  * when ifp == NULL, the caller is responsible for filling scopeid.
573  *
574  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
575  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
576  */
577 static int
578 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
579     struct in6_addr *in6, int oldmcprefix)
580 {
581 	struct prison *pr;
582 	const char *p;
583 	u_char *q;
584 	MD5_CTX ctxt;
585 	u_int8_t digest[16];
586 	char l;
587 	char n[64];	/* a single label must not exceed 63 chars */
588 
589 	/*
590 	 * If no name is given and namelen is -1,
591 	 * we try to do the hostname lookup ourselves.
592 	 */
593 	if (!name && namelen == -1) {
594 		pr = curthread->td_ucred->cr_prison;
595 		mtx_lock(&pr->pr_mtx);
596 		name = pr->pr_hostname;
597 		namelen = strlen(name);
598 	} else
599 		pr = NULL;
600 	if (!name || !namelen) {
601 		if (pr != NULL)
602 			mtx_unlock(&pr->pr_mtx);
603 		return -1;
604 	}
605 
606 	p = name;
607 	while (p && *p && *p != '.' && p - name < namelen)
608 		p++;
609 	if (p == name || p - name > sizeof(n) - 1) {
610 		if (pr != NULL)
611 			mtx_unlock(&pr->pr_mtx);
612 		return -1;	/* label too long */
613 	}
614 	l = p - name;
615 	strncpy(n, name, l);
616 	if (pr != NULL)
617 		mtx_unlock(&pr->pr_mtx);
618 	n[(int)l] = '\0';
619 	for (q = n; *q; q++) {
620 		if ('A' <= *q && *q <= 'Z')
621 			*q = *q - 'A' + 'a';
622 	}
623 
624 	/* generate 16 bytes of pseudo-random value. */
625 	bzero(&ctxt, sizeof(ctxt));
626 	MD5Init(&ctxt);
627 	MD5Update(&ctxt, &l, sizeof(l));
628 	MD5Update(&ctxt, n, l);
629 	MD5Final(digest, &ctxt);
630 
631 	bzero(in6, sizeof(*in6));
632 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
633 	in6->s6_addr8[11] = 2;
634 	if (oldmcprefix == 0) {
635 		in6->s6_addr8[12] = 0xff;
636 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
637 		bcopy(digest, &in6->s6_addr8[13], 3);
638 	} else {
639 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
640 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
641 	}
642 	if (in6_setscope(in6, ifp, NULL))
643 		return (-1); /* XXX: should not fail */
644 
645 	return 0;
646 }
647 
648 int
649 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
650     struct in6_addr *in6)
651 {
652 
653 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
654 }
655 
656 int
657 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
658     struct in6_addr *in6)
659 {
660 
661 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
662 }
663 
664 /*
665  * XXX multiple loopback interface needs more care.  for instance,
666  * nodelocal address needs to be configured onto only one of them.
667  * XXX multiple link-local address case
668  *
669  * altifp - secondary EUI64 source
670  */
671 void
672 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
673 {
674 	struct in6_ifaddr *ia;
675 
676 	if (ifp->if_afdata[AF_INET6] == NULL)
677 		return;
678 	/*
679 	 * quirks based on interface type
680 	 */
681 	switch (ifp->if_type) {
682 	case IFT_STF:
683 		/*
684 		 * 6to4 interface is a very special kind of beast.
685 		 * no multicast, no linklocal.  RFC2529 specifies how to make
686 		 * linklocals for 6to4 interface, but there's no use and
687 		 * it is rather harmful to have one.
688 		 */
689 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
690 		ND_IFINFO(ifp)->flags |= ND6_IFF_NO_DAD;
691 		break;
692 	default:
693 		break;
694 	}
695 
696 	/*
697 	 * usually, we require multicast capability to the interface
698 	 */
699 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
700 		nd6log((LOG_INFO, "in6_ifattach: "
701 		    "%s is not multicast capable, IPv6 not enabled\n",
702 		    if_name(ifp)));
703 		return;
704 	}
705 
706 	/*
707 	 * assign loopback address for loopback interface.
708 	 */
709 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
710 		/*
711 		 * check that loopback address doesn't exist yet.
712 		 */
713 		ia = in6ifa_ifwithaddr(&in6addr_loopback, 0);
714 		if (ia == NULL)
715 			in6_ifattach_loopback(ifp);
716 		else
717 			ifa_free(&ia->ia_ifa);
718 	}
719 
720 	/*
721 	 * assign a link-local address, if there's none.
722 	 */
723 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
724 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
725 		struct epoch_tracker et;
726 
727 		NET_EPOCH_ENTER(et);
728 		ia = in6ifa_ifpforlinklocal(ifp, 0);
729 		NET_EPOCH_EXIT(et);
730 		if (ia == NULL)
731 			in6_ifattach_linklocal(ifp, altifp);
732 		else
733 			ifa_free(&ia->ia_ifa);
734 	}
735 
736 	/* update dynamically. */
737 	if (V_in6_maxmtu < ifp->if_mtu)
738 		V_in6_maxmtu = ifp->if_mtu;
739 }
740 
741 /*
742  * NOTE: in6_ifdetach() does not support loopback if at this moment.
743  *
744  * When shutting down a VNET we clean up layers top-down.  In that case
745  * upper layer protocols (ulp) are cleaned up already and locks are destroyed
746  * and we must not call into these cleanup functions anymore, thus purgeulp
747  * is set to 0 in that case by in6_ifdetach_destroy().
748  * The normal case of destroying a (cloned) interface still needs to cleanup
749  * everything related to the interface and will have purgeulp set to 1.
750  */
751 static void
752 _in6_ifdetach(struct ifnet *ifp, int purgeulp)
753 {
754 	struct ifaddr *ifa, *next;
755 
756 	if (ifp->if_afdata[AF_INET6] == NULL)
757 		return;
758 
759 	/*
760 	 * nuke any of IPv6 addresses we have
761 	 */
762 	CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
763 		if (ifa->ifa_addr->sa_family != AF_INET6)
764 			continue;
765 		in6_purgeaddr(ifa);
766 	}
767 	if (purgeulp) {
768 		IN6_MULTI_LOCK();
769 		in6_pcbpurgeif0(&V_udbinfo, ifp);
770 		in6_pcbpurgeif0(&V_ulitecbinfo, ifp);
771 		in6_pcbpurgeif0(&V_ripcbinfo, ifp);
772 		IN6_MULTI_UNLOCK();
773 	}
774 	/* leave from all multicast groups joined */
775 	in6_purgemaddrs(ifp);
776 
777 	/*
778 	 * Remove neighbor management table.
779 	 * Enabling the nd6_purge will panic on vmove for interfaces on VNET
780 	 * teardown as the IPv6 layer is cleaned up already and the locks
781 	 * are destroyed.
782 	 */
783 	if (purgeulp)
784 		nd6_purge(ifp);
785 }
786 
787 void
788 in6_ifdetach(struct ifnet *ifp)
789 {
790 
791 	_in6_ifdetach(ifp, 1);
792 }
793 
794 void
795 in6_ifdetach_destroy(struct ifnet *ifp)
796 {
797 
798 	_in6_ifdetach(ifp, 0);
799 }
800 
801 int
802 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
803     const u_int8_t *baseid, int generate)
804 {
805 	u_int8_t nullbuf[8];
806 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
807 
808 	bzero(nullbuf, sizeof(nullbuf));
809 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
810 		/* we've never created a random ID.  Create a new one. */
811 		generate = 1;
812 	}
813 
814 	if (generate) {
815 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
816 
817 		/* generate_tmp_ifid will update seedn and buf */
818 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
819 		    ndi->randomid);
820 	}
821 	bcopy(ndi->randomid, retbuf, 8);
822 
823 	return (0);
824 }
825 
826 void
827 in6_tmpaddrtimer(void *arg)
828 {
829 	CURVNET_SET((struct vnet *) arg);
830 	struct nd_ifinfo *ndi;
831 	u_int8_t nullbuf[8];
832 	struct ifnet *ifp;
833 
834 	callout_reset(&V_in6_tmpaddrtimer_ch,
835 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
836 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
837 
838 	bzero(nullbuf, sizeof(nullbuf));
839 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
840 		if (ifp->if_afdata[AF_INET6] == NULL)
841 			continue;
842 		ndi = ND_IFINFO(ifp);
843 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
844 			/*
845 			 * We've been generating a random ID on this interface.
846 			 * Create a new one.
847 			 */
848 			(void)generate_tmp_ifid(ndi->randomseed0,
849 			    ndi->randomseed1, ndi->randomid);
850 		}
851 	}
852 
853 	CURVNET_RESTORE();
854 }
855 
856 static void
857 in6_purgemaddrs(struct ifnet *ifp)
858 {
859 	struct in6_multi_head inmh;
860 
861 	SLIST_INIT(&inmh);
862 	IN6_MULTI_LOCK();
863 	IN6_MULTI_LIST_LOCK();
864 	mld_ifdetach(ifp, &inmh);
865 	IN6_MULTI_LIST_UNLOCK();
866 	IN6_MULTI_UNLOCK();
867 	in6m_release_list_deferred(&inmh);
868 
869 	/*
870 	 * Make sure all multicast deletions invoking if_ioctl() are
871 	 * completed before returning. Else we risk accessing a freed
872 	 * ifnet structure pointer.
873 	 */
874 	in6m_release_wait(NULL);
875 }
876 
877 void
878 in6_ifattach_destroy(void)
879 {
880 
881 	callout_drain(&V_in6_tmpaddrtimer_ch);
882 }
883 
884 static void
885 in6_ifattach_init(void *dummy)
886 {
887 
888 	/* Timer for regeneranation of temporary addresses randomize ID. */
889 	callout_init(&V_in6_tmpaddrtimer_ch, 0);
890 	callout_reset(&V_in6_tmpaddrtimer_ch,
891 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
892 	    V_ip6_temp_regen_advance) * hz,
893 	    in6_tmpaddrtimer, curvnet);
894 }
895 
896 /*
897  * Cheat.
898  * This must be after route_init(), which is now SI_ORDER_THIRD.
899  */
900 SYSINIT(in6_ifattach_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
901     in6_ifattach_init, NULL);
902