xref: /freebsd/sys/netinet6/in6_ifattach.c (revision 911f0260390e18cf85f3dbf2c719b593efdc1e3c)
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_private.h>
54 #include <net/if_types.h>
55 #include <net/route.h>
56 #include <net/vnet.h>
57 
58 #include <netinet/in.h>
59 #include <netinet/in_var.h>
60 #include <netinet/if_ether.h>
61 #include <netinet/in_pcb.h>
62 #include <netinet/ip_var.h>
63 #include <netinet/udp.h>
64 #include <netinet/udp_var.h>
65 
66 #include <netinet/ip6.h>
67 #include <netinet6/ip6_var.h>
68 #include <netinet6/in6_var.h>
69 #include <netinet6/in6_pcb.h>
70 #include <netinet6/in6_ifattach.h>
71 #include <netinet6/ip6_var.h>
72 #include <netinet6/nd6.h>
73 #include <netinet6/mld6_var.h>
74 #include <netinet6/scope6_var.h>
75 
76 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
77 
78 #ifdef IP6_AUTO_LINKLOCAL
79 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
80 #else
81 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
82 #endif
83 
84 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
85 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
86 
87 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
88 #define	V_ripcbinfo			VNET(ripcbinfo)
89 
90 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
91 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
92 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
93 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
94 static int in6_ifattach_loopback(struct ifnet *);
95 static void in6_purgemaddrs(struct ifnet *);
96 
97 #define EUI64_GBIT	0x01
98 #define EUI64_UBIT	0x02
99 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
100 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
101 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
102 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
103 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
104 
105 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
106 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
107 
108 /*
109  * Generate a last-resort interface identifier, when the machine has no
110  * IEEE802/EUI64 address sources.
111  * The goal here is to get an interface identifier that is
112  * (1) random enough and (2) does not change across reboot.
113  * We currently use MD5(hostname) for it.
114  *
115  * in6 - upper 64bits are preserved
116  */
117 static int
118 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
119 {
120 	MD5_CTX ctxt;
121 	struct prison *pr;
122 	u_int8_t digest[16];
123 	int hostnamelen;
124 
125 	pr = curthread->td_ucred->cr_prison;
126 	mtx_lock(&pr->pr_mtx);
127 	hostnamelen = strlen(pr->pr_hostname);
128 #if 0
129 	/* we need at least several letters as seed for ifid */
130 	if (hostnamelen < 3) {
131 		mtx_unlock(&pr->pr_mtx);
132 		return -1;
133 	}
134 #endif
135 
136 	/* generate 8 bytes of pseudo-random value. */
137 	bzero(&ctxt, sizeof(ctxt));
138 	MD5Init(&ctxt);
139 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
140 	mtx_unlock(&pr->pr_mtx);
141 	MD5Final(digest, &ctxt);
142 
143 	/* assumes sizeof(digest) > sizeof(ifid) */
144 	bcopy(digest, &in6->s6_addr[8], 8);
145 
146 	/* make sure to set "u" bit to local, and "g" bit to individual. */
147 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
148 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
149 
150 	/* convert EUI64 into IPv6 interface identifier */
151 	EUI64_TO_IFID(in6);
152 
153 	return 0;
154 }
155 
156 static int
157 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
158 {
159 	MD5_CTX ctxt;
160 	u_int8_t seed[16], digest[16], nullbuf[8];
161 	u_int32_t val32;
162 
163 	/* If there's no history, start with a random seed. */
164 	bzero(nullbuf, sizeof(nullbuf));
165 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
166 		int i;
167 
168 		for (i = 0; i < 2; i++) {
169 			val32 = arc4random();
170 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
171 		}
172 	} else
173 		bcopy(seed0, seed, 8);
174 
175 	/* copy the right-most 64-bits of the given address */
176 	/* XXX assumption on the size of IFID */
177 	bcopy(seed1, &seed[8], 8);
178 
179 	if (0) {		/* for debugging purposes only */
180 		int i;
181 
182 		printf("generate_tmp_ifid: new randomized ID from: ");
183 		for (i = 0; i < 16; i++)
184 			printf("%02x", seed[i]);
185 		printf(" ");
186 	}
187 
188 	/* generate 16 bytes of pseudo-random value. */
189 	bzero(&ctxt, sizeof(ctxt));
190 	MD5Init(&ctxt);
191 	MD5Update(&ctxt, seed, sizeof(seed));
192 	MD5Final(digest, &ctxt);
193 
194 	/*
195 	 * RFC 3041 3.2.1. (3)
196 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
197 	 * left-most bit is numbered 0) to zero.
198 	 */
199 	bcopy(digest, ret, 8);
200 	ret[0] &= ~EUI64_UBIT;
201 
202 	/*
203 	 * XXX: we'd like to ensure that the generated value is not zero
204 	 * for simplicity.  If the caclculated digest happens to be zero,
205 	 * use a random non-zero value as the last resort.
206 	 */
207 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
208 		nd6log((LOG_INFO,
209 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
210 
211 		val32 = arc4random();
212 		val32 = 1 + (val32 % (0xffffffff - 1));
213 	}
214 
215 	/*
216 	 * RFC 3041 3.2.1. (4)
217 	 * Take the rightmost 64-bits of the MD5 digest and save them in
218 	 * stable storage as the history value to be used in the next
219 	 * iteration of the algorithm.
220 	 */
221 	bcopy(&digest[8], seed0, 8);
222 
223 	if (0) {		/* for debugging purposes only */
224 		int i;
225 
226 		printf("to: ");
227 		for (i = 0; i < 16; i++)
228 			printf("%02x", digest[i]);
229 		printf("\n");
230 	}
231 
232 	return 0;
233 }
234 
235 /*
236  * Get interface identifier for the specified interface.
237  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
238  *
239  * in6 - upper 64bits are preserved
240  */
241 int
242 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
243 {
244 	struct ifaddr *ifa;
245 	struct sockaddr_dl *sdl;
246 	u_int8_t *addr;
247 	size_t addrlen;
248 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
249 	static u_int8_t allone[8] =
250 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
251 
252 	NET_EPOCH_ASSERT();
253 
254 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
255 		if (ifa->ifa_addr->sa_family != AF_LINK)
256 			continue;
257 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
258 		if (sdl == NULL)
259 			continue;
260 		if (sdl->sdl_alen == 0)
261 			continue;
262 
263 		goto found;
264 	}
265 
266 	return -1;
267 
268 found:
269 	addr = LLADDR(sdl);
270 	addrlen = sdl->sdl_alen;
271 
272 	/* get EUI64 */
273 	switch (ifp->if_type) {
274 	case IFT_BRIDGE:
275 	case IFT_ETHER:
276 	case IFT_L2VLAN:
277 	case IFT_ATM:
278 	case IFT_IEEE1394:
279 		/* IEEE802/EUI64 cases - what others? */
280 		/* IEEE1394 uses 16byte length address starting with EUI64 */
281 		if (addrlen > 8)
282 			addrlen = 8;
283 
284 		/* look at IEEE802/EUI64 only */
285 		if (addrlen != 8 && addrlen != 6)
286 			return -1;
287 
288 		/*
289 		 * check for invalid MAC address - on bsdi, we see it a lot
290 		 * since wildboar configures all-zero MAC on pccard before
291 		 * card insertion.
292 		 */
293 		if (bcmp(addr, allzero, addrlen) == 0)
294 			return -1;
295 		if (bcmp(addr, allone, addrlen) == 0)
296 			return -1;
297 
298 		/* make EUI64 address */
299 		if (addrlen == 8)
300 			bcopy(addr, &in6->s6_addr[8], 8);
301 		else if (addrlen == 6) {
302 			in6->s6_addr[8] = addr[0];
303 			in6->s6_addr[9] = addr[1];
304 			in6->s6_addr[10] = addr[2];
305 			in6->s6_addr[11] = 0xff;
306 			in6->s6_addr[12] = 0xfe;
307 			in6->s6_addr[13] = addr[3];
308 			in6->s6_addr[14] = addr[4];
309 			in6->s6_addr[15] = addr[5];
310 		}
311 		break;
312 
313 	case IFT_GIF:
314 	case IFT_STF:
315 		/*
316 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
317 		 * however, IPv4 address is not very suitable as unique
318 		 * identifier source (can be renumbered).
319 		 * we don't do this.
320 		 */
321 		return -1;
322 
323 	case IFT_INFINIBAND:
324 		if (addrlen != 20)
325 			return -1;
326 		bcopy(addr + 12, &in6->s6_addr[8], 8);
327 		break;
328 
329 	default:
330 		return -1;
331 	}
332 
333 	/* sanity check: g bit must not indicate "group" */
334 	if (EUI64_GROUP(in6))
335 		return -1;
336 
337 	/* convert EUI64 into IPv6 interface identifier */
338 	EUI64_TO_IFID(in6);
339 
340 	/*
341 	 * sanity check: ifid must not be all zero, avoid conflict with
342 	 * subnet router anycast
343 	 */
344 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
345 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0)
346 		return -1;
347 
348 	return 0;
349 }
350 
351 /*
352  * Get interface identifier for the specified interface.  If it is not
353  * available on ifp0, borrow interface identifier from other information
354  * sources.
355  *
356  * altifp - secondary EUI64 source
357  */
358 static int
359 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
360     struct in6_addr *in6)
361 {
362 	struct ifnet *ifp;
363 
364 	NET_EPOCH_ASSERT();
365 
366 	/* first, try to get it from the interface itself */
367 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
368 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
369 		    if_name(ifp0)));
370 		goto success;
371 	}
372 
373 	/* try secondary EUI64 source. this basically is for ATM PVC */
374 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
375 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
376 		    if_name(ifp0), if_name(altifp)));
377 		goto success;
378 	}
379 
380 	/* next, try to get it from some other hardware interface */
381 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
382 		if (ifp == ifp0)
383 			continue;
384 		if (in6_get_hw_ifid(ifp, in6) != 0)
385 			continue;
386 
387 		/*
388 		 * to borrow ifid from other interface, ifid needs to be
389 		 * globally unique
390 		 */
391 		if (IFID_UNIVERSAL(in6)) {
392 			nd6log((LOG_DEBUG,
393 			    "%s: borrow interface identifier from %s\n",
394 			    if_name(ifp0), if_name(ifp)));
395 			goto success;
396 		}
397 	}
398 
399 	/* last resort: get from random number source */
400 	if (get_rand_ifid(ifp, in6) == 0) {
401 		nd6log((LOG_DEBUG,
402 		    "%s: interface identifier generated by random number\n",
403 		    if_name(ifp0)));
404 		goto success;
405 	}
406 
407 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
408 	return -1;
409 
410 success:
411 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
412 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
413 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
414 	    in6->s6_addr[14], in6->s6_addr[15]));
415 	return 0;
416 }
417 
418 /*
419  * altifp - secondary EUI64 source
420  */
421 static int
422 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
423 {
424 	struct in6_ifaddr *ia;
425 	struct in6_aliasreq ifra;
426 	struct nd_prefixctl pr0;
427 	struct epoch_tracker et;
428 	struct nd_prefix *pr;
429 	int error;
430 
431 	/*
432 	 * configure link-local address.
433 	 */
434 	in6_prepare_ifra(&ifra, NULL, &in6mask64);
435 
436 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
437 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
438 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
439 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
440 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
441 	} else {
442 		NET_EPOCH_ENTER(et);
443 		error = get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr);
444 		NET_EPOCH_EXIT(et);
445 		if (error != 0) {
446 			nd6log((LOG_ERR,
447 			    "%s: no ifid available\n", if_name(ifp)));
448 			return (-1);
449 		}
450 	}
451 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
452 		return (-1);
453 
454 	/* link-local addresses should NEVER expire. */
455 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
456 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
457 
458 	/*
459 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
460 	 * a link-local address. We can set the 3rd argument to NULL, because
461 	 * we know there's no other link-local address on the interface
462 	 * and therefore we are adding one (instead of updating one).
463 	 */
464 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
465 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
466 		/*
467 		 * XXX: When the interface does not support IPv6, this call
468 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
469 		 * notification is rather confusing in this case, so just
470 		 * suppress it.  (jinmei@kame.net 20010130)
471 		 */
472 		if (error != EAFNOSUPPORT)
473 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
474 			    "configure a link-local address on %s "
475 			    "(errno=%d)\n",
476 			    if_name(ifp), error));
477 		return (-1);
478 	}
479 
480 	NET_EPOCH_ENTER(et);
481 	ia = in6ifa_ifpforlinklocal(ifp, 0);
482 	NET_EPOCH_EXIT(et);
483 	if (ia == NULL) {
484 		/*
485 		 * Another thread removed the address that we just added.
486 		 * This should be rare, but it happens.
487 		 */
488 		nd6log((LOG_NOTICE, "%s: %s: new link-local address "
489 			"disappeared\n", __func__, if_name(ifp)));
490 		return (-1);
491 	}
492 	ifa_free(&ia->ia_ifa);
493 
494 	/*
495 	 * Make the link-local prefix (fe80::%link/64) as on-link.
496 	 * Since we'd like to manage prefixes separately from addresses,
497 	 * we make an ND6 prefix structure for the link-local prefix,
498 	 * and add it to the prefix list as a never-expire prefix.
499 	 * XXX: this change might affect some existing code base...
500 	 */
501 	bzero(&pr0, sizeof(pr0));
502 	pr0.ndpr_ifp = ifp;
503 	/* this should be 64 at this moment. */
504 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
505 	pr0.ndpr_prefix = ifra.ifra_addr;
506 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
507 	IN6_MASK_ADDR(&pr0.ndpr_prefix.sin6_addr, &in6mask64);
508 	/*
509 	 * Initialize parameters.  The link-local prefix must always be
510 	 * on-link, and its lifetimes never expire.
511 	 */
512 	pr0.ndpr_raf_onlink = 1;
513 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
514 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
515 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
516 	/*
517 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
518 	 * probably returns NULL.  However, we cannot always expect the result.
519 	 * For example, if we first remove the (only) existing link-local
520 	 * address, and then reconfigure another one, the prefix is still
521 	 * valid with referring to the old link-local address.
522 	 */
523 	if ((pr = nd6_prefix_lookup(&pr0)) == NULL) {
524 		if ((error = nd6_prelist_add(&pr0, NULL, &pr)) != 0)
525 			return (error);
526 		/* Reference prefix */
527 		ia->ia6_ndpr = pr;
528 		pr->ndpr_addrcnt++;
529 	} else
530 		nd6_prefix_rele(pr);
531 
532 	return 0;
533 }
534 
535 /*
536  * ifp - must be IFT_LOOP
537  */
538 static int
539 in6_ifattach_loopback(struct ifnet *ifp)
540 {
541 	struct in6_aliasreq ifra;
542 	int error;
543 
544 	in6_prepare_ifra(&ifra, &in6addr_loopback, &in6mask128);
545 
546 	/*
547 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
548 	 * address.  Follows IPv4 practice - see in_ifinit().
549 	 */
550 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
551 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
552 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
553 
554 	/* the loopback  address should NEVER expire. */
555 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
556 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
557 
558 	/*
559 	 * We are sure that this is a newly assigned address, so we can set
560 	 * NULL to the 3rd arg.
561 	 */
562 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
563 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
564 		    "the loopback address on %s (errno=%d)\n",
565 		    if_name(ifp), error));
566 		return (-1);
567 	}
568 
569 	return 0;
570 }
571 
572 /*
573  * compute NI group address, based on the current hostname setting.
574  * see RFC 4620.
575  *
576  * when ifp == NULL, the caller is responsible for filling scopeid.
577  *
578  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
579  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
580  */
581 static int
582 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
583     struct in6_addr *in6, int oldmcprefix)
584 {
585 	struct prison *pr;
586 	const char *p;
587 	u_char *q;
588 	MD5_CTX ctxt;
589 	u_int8_t digest[16];
590 	char l;
591 	char n[64];	/* a single label must not exceed 63 chars */
592 
593 	/*
594 	 * If no name is given and namelen is -1,
595 	 * we try to do the hostname lookup ourselves.
596 	 */
597 	if (!name && namelen == -1) {
598 		pr = curthread->td_ucred->cr_prison;
599 		mtx_lock(&pr->pr_mtx);
600 		name = pr->pr_hostname;
601 		namelen = strlen(name);
602 	} else
603 		pr = NULL;
604 	if (!name || !namelen) {
605 		if (pr != NULL)
606 			mtx_unlock(&pr->pr_mtx);
607 		return -1;
608 	}
609 
610 	p = name;
611 	while (p && *p && *p != '.' && p - name < namelen)
612 		p++;
613 	if (p == name || p - name > sizeof(n) - 1) {
614 		if (pr != NULL)
615 			mtx_unlock(&pr->pr_mtx);
616 		return -1;	/* label too long */
617 	}
618 	l = p - name;
619 	strncpy(n, name, l);
620 	if (pr != NULL)
621 		mtx_unlock(&pr->pr_mtx);
622 	n[(int)l] = '\0';
623 	for (q = n; *q; q++) {
624 		if ('A' <= *q && *q <= 'Z')
625 			*q = *q - 'A' + 'a';
626 	}
627 
628 	/* generate 16 bytes of pseudo-random value. */
629 	bzero(&ctxt, sizeof(ctxt));
630 	MD5Init(&ctxt);
631 	MD5Update(&ctxt, &l, sizeof(l));
632 	MD5Update(&ctxt, n, l);
633 	MD5Final(digest, &ctxt);
634 
635 	bzero(in6, sizeof(*in6));
636 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
637 	in6->s6_addr8[11] = 2;
638 	if (oldmcprefix == 0) {
639 		in6->s6_addr8[12] = 0xff;
640 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
641 		bcopy(digest, &in6->s6_addr8[13], 3);
642 	} else {
643 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
644 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
645 	}
646 	if (in6_setscope(in6, ifp, NULL))
647 		return (-1); /* XXX: should not fail */
648 
649 	return 0;
650 }
651 
652 int
653 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
654     struct in6_addr *in6)
655 {
656 
657 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
658 }
659 
660 int
661 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
662     struct in6_addr *in6)
663 {
664 
665 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
666 }
667 
668 /*
669  * XXX multiple loopback interface needs more care.  for instance,
670  * nodelocal address needs to be configured onto only one of them.
671  * XXX multiple link-local address case
672  *
673  * altifp - secondary EUI64 source
674  */
675 void
676 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
677 {
678 	struct in6_ifaddr *ia;
679 
680 	if (ifp->if_afdata[AF_INET6] == NULL)
681 		return;
682 	/*
683 	 * quirks based on interface type
684 	 */
685 	switch (ifp->if_type) {
686 	case IFT_STF:
687 		/*
688 		 * 6to4 interface is a very special kind of beast.
689 		 * no multicast, no linklocal.  RFC2529 specifies how to make
690 		 * linklocals for 6to4 interface, but there's no use and
691 		 * it is rather harmful to have one.
692 		 */
693 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
694 		ND_IFINFO(ifp)->flags |= ND6_IFF_NO_DAD;
695 		break;
696 	default:
697 		break;
698 	}
699 
700 	/*
701 	 * usually, we require multicast capability to the interface
702 	 */
703 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
704 		nd6log((LOG_INFO, "in6_ifattach: "
705 		    "%s is not multicast capable, IPv6 not enabled\n",
706 		    if_name(ifp)));
707 		return;
708 	}
709 
710 	/*
711 	 * assign loopback address for loopback interface.
712 	 */
713 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
714 		/*
715 		 * check that loopback address doesn't exist yet.
716 		 */
717 		ia = in6ifa_ifwithaddr(&in6addr_loopback, 0, false);
718 		if (ia == NULL)
719 			in6_ifattach_loopback(ifp);
720 	}
721 
722 	/*
723 	 * assign a link-local address, if there's none.
724 	 */
725 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
726 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
727 		struct epoch_tracker et;
728 
729 		NET_EPOCH_ENTER(et);
730 		ia = in6ifa_ifpforlinklocal(ifp, 0);
731 		NET_EPOCH_EXIT(et);
732 		if (ia == NULL)
733 			in6_ifattach_linklocal(ifp, altifp);
734 		else
735 			ifa_free(&ia->ia_ifa);
736 	}
737 
738 	/* update dynamically. */
739 	if (V_in6_maxmtu < ifp->if_mtu)
740 		V_in6_maxmtu = ifp->if_mtu;
741 }
742 
743 /*
744  * NOTE: in6_ifdetach() does not support loopback if at this moment.
745  *
746  * When shutting down a VNET we clean up layers top-down.  In that case
747  * upper layer protocols (ulp) are cleaned up already and locks are destroyed
748  * and we must not call into these cleanup functions anymore, thus purgeulp
749  * is set to 0 in that case by in6_ifdetach_destroy().
750  * The normal case of destroying a (cloned) interface still needs to cleanup
751  * everything related to the interface and will have purgeulp set to 1.
752  */
753 static void
754 _in6_ifdetach(struct ifnet *ifp, int purgeulp)
755 {
756 	struct ifaddr *ifa, *next;
757 
758 	if (ifp->if_afdata[AF_INET6] == NULL)
759 		return;
760 
761 	/*
762 	 * nuke any of IPv6 addresses we have
763 	 */
764 	CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
765 		if (ifa->ifa_addr->sa_family != AF_INET6)
766 			continue;
767 		in6_purgeaddr(ifa);
768 	}
769 	if (purgeulp) {
770 		IN6_MULTI_LOCK();
771 		in6_pcbpurgeif0(&V_udbinfo, ifp);
772 		in6_pcbpurgeif0(&V_ulitecbinfo, ifp);
773 		in6_pcbpurgeif0(&V_ripcbinfo, ifp);
774 		IN6_MULTI_UNLOCK();
775 	}
776 	/* leave from all multicast groups joined */
777 	in6_purgemaddrs(ifp);
778 
779 	/*
780 	 * Remove neighbor management table.
781 	 * Enabling the nd6_purge will panic on vmove for interfaces on VNET
782 	 * teardown as the IPv6 layer is cleaned up already and the locks
783 	 * are destroyed.
784 	 */
785 	if (purgeulp)
786 		nd6_purge(ifp);
787 }
788 
789 void
790 in6_ifdetach(struct ifnet *ifp)
791 {
792 
793 	_in6_ifdetach(ifp, 1);
794 }
795 
796 void
797 in6_ifdetach_destroy(struct ifnet *ifp)
798 {
799 
800 	_in6_ifdetach(ifp, 0);
801 }
802 
803 int
804 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
805     const u_int8_t *baseid, int generate)
806 {
807 	u_int8_t nullbuf[8];
808 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
809 
810 	bzero(nullbuf, sizeof(nullbuf));
811 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
812 		/* we've never created a random ID.  Create a new one. */
813 		generate = 1;
814 	}
815 
816 	if (generate) {
817 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
818 
819 		/* generate_tmp_ifid will update seedn and buf */
820 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
821 		    ndi->randomid);
822 	}
823 	bcopy(ndi->randomid, retbuf, 8);
824 
825 	return (0);
826 }
827 
828 void
829 in6_tmpaddrtimer(void *arg)
830 {
831 	CURVNET_SET((struct vnet *) arg);
832 	struct epoch_tracker et;
833 	struct nd_ifinfo *ndi;
834 	u_int8_t nullbuf[8];
835 	struct ifnet *ifp;
836 
837 	callout_reset(&V_in6_tmpaddrtimer_ch,
838 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
839 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
840 
841 	bzero(nullbuf, sizeof(nullbuf));
842 	NET_EPOCH_ENTER(et);
843 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
844 		if (ifp->if_afdata[AF_INET6] == NULL)
845 			continue;
846 		ndi = ND_IFINFO(ifp);
847 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
848 			/*
849 			 * We've been generating a random ID on this interface.
850 			 * Create a new one.
851 			 */
852 			(void)generate_tmp_ifid(ndi->randomseed0,
853 			    ndi->randomseed1, ndi->randomid);
854 		}
855 	}
856 	NET_EPOCH_EXIT(et);
857 	CURVNET_RESTORE();
858 }
859 
860 static void
861 in6_purgemaddrs(struct ifnet *ifp)
862 {
863 	struct in6_multi_head inmh;
864 
865 	SLIST_INIT(&inmh);
866 	IN6_MULTI_LOCK();
867 	IN6_MULTI_LIST_LOCK();
868 	mld_ifdetach(ifp, &inmh);
869 	IN6_MULTI_LIST_UNLOCK();
870 	IN6_MULTI_UNLOCK();
871 	in6m_release_list_deferred(&inmh);
872 
873 	/*
874 	 * Make sure all multicast deletions invoking if_ioctl() are
875 	 * completed before returning. Else we risk accessing a freed
876 	 * ifnet structure pointer.
877 	 */
878 	in6m_release_wait(NULL);
879 }
880 
881 void
882 in6_ifattach_destroy(void)
883 {
884 
885 	callout_drain(&V_in6_tmpaddrtimer_ch);
886 }
887 
888 static void
889 in6_ifattach_init(void *dummy)
890 {
891 
892 	/* Timer for regeneranation of temporary addresses randomize ID. */
893 	callout_init(&V_in6_tmpaddrtimer_ch, 1);
894 	callout_reset(&V_in6_tmpaddrtimer_ch,
895 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
896 	    V_ip6_temp_regen_advance) * hz,
897 	    in6_tmpaddrtimer, curvnet);
898 }
899 
900 /*
901  * Cheat.
902  * This must be after route_init(), which is now SI_ORDER_THIRD.
903  */
904 SYSINIT(in6_ifattach_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
905     in6_ifattach_init, NULL);
906