xref: /freebsd/sys/netinet6/in6_ifattach.c (revision 595e514d0df2bac5b813d35f83e32875dbf16a83)
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_dl.h>
48 #include <net/if_types.h>
49 #include <net/route.h>
50 #include <net/vnet.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_var.h>
54 #include <netinet/if_ether.h>
55 #include <netinet/in_pcb.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/udp.h>
58 #include <netinet/udp_var.h>
59 
60 #include <netinet/ip6.h>
61 #include <netinet6/ip6_var.h>
62 #include <netinet6/in6_var.h>
63 #include <netinet6/in6_pcb.h>
64 #include <netinet6/in6_ifattach.h>
65 #include <netinet6/ip6_var.h>
66 #include <netinet6/nd6.h>
67 #include <netinet6/mld6_var.h>
68 #include <netinet6/scope6_var.h>
69 
70 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
71 
72 #ifdef IP6_AUTO_LINKLOCAL
73 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
74 #else
75 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
76 #endif
77 
78 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
79 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
80 
81 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
82 #define	V_ripcbinfo			VNET(ripcbinfo)
83 
84 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
85 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
86 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
87 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
88 static int in6_ifattach_loopback(struct ifnet *);
89 static void in6_purgemaddrs(struct ifnet *);
90 
91 #define EUI64_GBIT	0x01
92 #define EUI64_UBIT	0x02
93 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
94 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
95 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
96 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
97 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
98 
99 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
100 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
101 
102 /*
103  * Generate a last-resort interface identifier, when the machine has no
104  * IEEE802/EUI64 address sources.
105  * The goal here is to get an interface identifier that is
106  * (1) random enough and (2) does not change across reboot.
107  * We currently use MD5(hostname) for it.
108  *
109  * in6 - upper 64bits are preserved
110  */
111 static int
112 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
113 {
114 	MD5_CTX ctxt;
115 	struct prison *pr;
116 	u_int8_t digest[16];
117 	int hostnamelen;
118 
119 	pr = curthread->td_ucred->cr_prison;
120 	mtx_lock(&pr->pr_mtx);
121 	hostnamelen = strlen(pr->pr_hostname);
122 #if 0
123 	/* we need at least several letters as seed for ifid */
124 	if (hostnamelen < 3) {
125 		mtx_unlock(&pr->pr_mtx);
126 		return -1;
127 	}
128 #endif
129 
130 	/* generate 8 bytes of pseudo-random value. */
131 	bzero(&ctxt, sizeof(ctxt));
132 	MD5Init(&ctxt);
133 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
134 	mtx_unlock(&pr->pr_mtx);
135 	MD5Final(digest, &ctxt);
136 
137 	/* assumes sizeof(digest) > sizeof(ifid) */
138 	bcopy(digest, &in6->s6_addr[8], 8);
139 
140 	/* make sure to set "u" bit to local, and "g" bit to individual. */
141 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
142 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
143 
144 	/* convert EUI64 into IPv6 interface identifier */
145 	EUI64_TO_IFID(in6);
146 
147 	return 0;
148 }
149 
150 static int
151 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
152 {
153 	MD5_CTX ctxt;
154 	u_int8_t seed[16], digest[16], nullbuf[8];
155 	u_int32_t val32;
156 
157 	/* If there's no history, start with a random seed. */
158 	bzero(nullbuf, sizeof(nullbuf));
159 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
160 		int i;
161 
162 		for (i = 0; i < 2; i++) {
163 			val32 = arc4random();
164 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
165 		}
166 	} else
167 		bcopy(seed0, seed, 8);
168 
169 	/* copy the right-most 64-bits of the given address */
170 	/* XXX assumption on the size of IFID */
171 	bcopy(seed1, &seed[8], 8);
172 
173 	if (0) {		/* for debugging purposes only */
174 		int i;
175 
176 		printf("generate_tmp_ifid: new randomized ID from: ");
177 		for (i = 0; i < 16; i++)
178 			printf("%02x", seed[i]);
179 		printf(" ");
180 	}
181 
182 	/* generate 16 bytes of pseudo-random value. */
183 	bzero(&ctxt, sizeof(ctxt));
184 	MD5Init(&ctxt);
185 	MD5Update(&ctxt, seed, sizeof(seed));
186 	MD5Final(digest, &ctxt);
187 
188 	/*
189 	 * RFC 3041 3.2.1. (3)
190 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
191 	 * left-most bit is numbered 0) to zero.
192 	 */
193 	bcopy(digest, ret, 8);
194 	ret[0] &= ~EUI64_UBIT;
195 
196 	/*
197 	 * XXX: we'd like to ensure that the generated value is not zero
198 	 * for simplicity.  If the caclculated digest happens to be zero,
199 	 * use a random non-zero value as the last resort.
200 	 */
201 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
202 		nd6log((LOG_INFO,
203 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
204 
205 		val32 = arc4random();
206 		val32 = 1 + (val32 % (0xffffffff - 1));
207 	}
208 
209 	/*
210 	 * RFC 3041 3.2.1. (4)
211 	 * Take the rightmost 64-bits of the MD5 digest and save them in
212 	 * stable storage as the history value to be used in the next
213 	 * iteration of the algorithm.
214 	 */
215 	bcopy(&digest[8], seed0, 8);
216 
217 	if (0) {		/* for debugging purposes only */
218 		int i;
219 
220 		printf("to: ");
221 		for (i = 0; i < 16; i++)
222 			printf("%02x", digest[i]);
223 		printf("\n");
224 	}
225 
226 	return 0;
227 }
228 
229 /*
230  * Get interface identifier for the specified interface.
231  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
232  *
233  * in6 - upper 64bits are preserved
234  */
235 int
236 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
237 {
238 	struct ifaddr *ifa;
239 	struct sockaddr_dl *sdl;
240 	u_int8_t *addr;
241 	size_t addrlen;
242 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
243 	static u_int8_t allone[8] =
244 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
245 
246 	IF_ADDR_RLOCK(ifp);
247 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
248 		if (ifa->ifa_addr->sa_family != AF_LINK)
249 			continue;
250 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
251 		if (sdl == NULL)
252 			continue;
253 		if (sdl->sdl_alen == 0)
254 			continue;
255 
256 		goto found;
257 	}
258 	IF_ADDR_RUNLOCK(ifp);
259 
260 	return -1;
261 
262 found:
263 	IF_ADDR_LOCK_ASSERT(ifp);
264 	addr = LLADDR(sdl);
265 	addrlen = sdl->sdl_alen;
266 
267 	/* get EUI64 */
268 	switch (ifp->if_type) {
269 	case IFT_ETHER:
270 	case IFT_L2VLAN:
271 	case IFT_FDDI:
272 	case IFT_ISO88025:
273 	case IFT_ATM:
274 	case IFT_IEEE1394:
275 #ifdef IFT_IEEE80211
276 	case IFT_IEEE80211:
277 #endif
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 			IF_ADDR_RUNLOCK(ifp);
286 			return -1;
287 		}
288 
289 		/*
290 		 * check for invalid MAC address - on bsdi, we see it a lot
291 		 * since wildboar configures all-zero MAC on pccard before
292 		 * card insertion.
293 		 */
294 		if (bcmp(addr, allzero, addrlen) == 0) {
295 			IF_ADDR_RUNLOCK(ifp);
296 			return -1;
297 		}
298 		if (bcmp(addr, allone, addrlen) == 0) {
299 			IF_ADDR_RUNLOCK(ifp);
300 			return -1;
301 		}
302 
303 		/* make EUI64 address */
304 		if (addrlen == 8)
305 			bcopy(addr, &in6->s6_addr[8], 8);
306 		else if (addrlen == 6) {
307 			in6->s6_addr[8] = addr[0];
308 			in6->s6_addr[9] = addr[1];
309 			in6->s6_addr[10] = addr[2];
310 			in6->s6_addr[11] = 0xff;
311 			in6->s6_addr[12] = 0xfe;
312 			in6->s6_addr[13] = addr[3];
313 			in6->s6_addr[14] = addr[4];
314 			in6->s6_addr[15] = addr[5];
315 		}
316 		break;
317 
318 	case IFT_ARCNET:
319 		if (addrlen != 1) {
320 			IF_ADDR_RUNLOCK(ifp);
321 			return -1;
322 		}
323 		if (!addr[0]) {
324 			IF_ADDR_RUNLOCK(ifp);
325 			return -1;
326 		}
327 
328 		bzero(&in6->s6_addr[8], 8);
329 		in6->s6_addr[15] = addr[0];
330 
331 		/*
332 		 * due to insufficient bitwidth, we mark it local.
333 		 */
334 		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
335 		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
336 		break;
337 
338 	case IFT_GIF:
339 #ifdef IFT_STF
340 	case IFT_STF:
341 #endif
342 		/*
343 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
344 		 * however, IPv4 address is not very suitable as unique
345 		 * identifier source (can be renumbered).
346 		 * we don't do this.
347 		 */
348 		IF_ADDR_RUNLOCK(ifp);
349 		return -1;
350 
351 	default:
352 		IF_ADDR_RUNLOCK(ifp);
353 		return -1;
354 	}
355 
356 	/* sanity check: g bit must not indicate "group" */
357 	if (EUI64_GROUP(in6)) {
358 		IF_ADDR_RUNLOCK(ifp);
359 		return -1;
360 	}
361 
362 	/* convert EUI64 into IPv6 interface identifier */
363 	EUI64_TO_IFID(in6);
364 
365 	/*
366 	 * sanity check: ifid must not be all zero, avoid conflict with
367 	 * subnet router anycast
368 	 */
369 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
370 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
371 		IF_ADDR_RUNLOCK(ifp);
372 		return -1;
373 	}
374 
375 	IF_ADDR_RUNLOCK(ifp);
376 	return 0;
377 }
378 
379 /*
380  * Get interface identifier for the specified interface.  If it is not
381  * available on ifp0, borrow interface identifier from other information
382  * sources.
383  *
384  * altifp - secondary EUI64 source
385  */
386 static int
387 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
388     struct in6_addr *in6)
389 {
390 	struct ifnet *ifp;
391 
392 	/* first, try to get it from the interface itself */
393 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
394 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
395 		    if_name(ifp0)));
396 		goto success;
397 	}
398 
399 	/* try secondary EUI64 source. this basically is for ATM PVC */
400 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
401 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
402 		    if_name(ifp0), if_name(altifp)));
403 		goto success;
404 	}
405 
406 	/* next, try to get it from some other hardware interface */
407 	IFNET_RLOCK_NOSLEEP();
408 	TAILQ_FOREACH(ifp, &V_ifnet, if_list) {
409 		if (ifp == ifp0)
410 			continue;
411 		if (in6_get_hw_ifid(ifp, in6) != 0)
412 			continue;
413 
414 		/*
415 		 * to borrow ifid from other interface, ifid needs to be
416 		 * globally unique
417 		 */
418 		if (IFID_UNIVERSAL(in6)) {
419 			nd6log((LOG_DEBUG,
420 			    "%s: borrow interface identifier from %s\n",
421 			    if_name(ifp0), if_name(ifp)));
422 			IFNET_RUNLOCK_NOSLEEP();
423 			goto success;
424 		}
425 	}
426 	IFNET_RUNLOCK_NOSLEEP();
427 
428 	/* last resort: get from random number source */
429 	if (get_rand_ifid(ifp, in6) == 0) {
430 		nd6log((LOG_DEBUG,
431 		    "%s: interface identifier generated by random number\n",
432 		    if_name(ifp0)));
433 		goto success;
434 	}
435 
436 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
437 	return -1;
438 
439 success:
440 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
441 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
442 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
443 	    in6->s6_addr[14], in6->s6_addr[15]));
444 	return 0;
445 }
446 
447 /*
448  * altifp - secondary EUI64 source
449  */
450 static int
451 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
452 {
453 	struct in6_ifaddr *ia;
454 	struct in6_aliasreq ifra;
455 	struct nd_prefixctl pr0;
456 	int i, error;
457 
458 	/*
459 	 * configure link-local address.
460 	 */
461 	bzero(&ifra, sizeof(ifra));
462 
463 	/*
464 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
465 	 * for safety.
466 	 */
467 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
468 
469 	ifra.ifra_addr.sin6_family = AF_INET6;
470 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
471 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
472 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
473 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
474 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
475 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
476 	} else {
477 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
478 			nd6log((LOG_ERR,
479 			    "%s: no ifid available\n", if_name(ifp)));
480 			return (-1);
481 		}
482 	}
483 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
484 		return (-1);
485 
486 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
487 	ifra.ifra_prefixmask.sin6_family = AF_INET6;
488 	ifra.ifra_prefixmask.sin6_addr = in6mask64;
489 	/* link-local addresses should NEVER expire. */
490 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
491 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
492 
493 	/*
494 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
495 	 * a link-local address. We can set the 3rd argument to NULL, because
496 	 * we know there's no other link-local address on the interface
497 	 * and therefore we are adding one (instead of updating one).
498 	 */
499 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
500 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
501 		/*
502 		 * XXX: When the interface does not support IPv6, this call
503 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
504 		 * notification is rather confusing in this case, so just
505 		 * suppress it.  (jinmei@kame.net 20010130)
506 		 */
507 		if (error != EAFNOSUPPORT)
508 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
509 			    "configure a link-local address on %s "
510 			    "(errno=%d)\n",
511 			    if_name(ifp), error));
512 		return (-1);
513 	}
514 
515 	ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
516 	KASSERT(ia != NULL, ("%s: ia == NULL, ifp=%p", __func__, ifp));
517 
518 	ifa_free(&ia->ia_ifa);
519 
520 	/*
521 	 * Make the link-local prefix (fe80::%link/64) as on-link.
522 	 * Since we'd like to manage prefixes separately from addresses,
523 	 * we make an ND6 prefix structure for the link-local prefix,
524 	 * and add it to the prefix list as a never-expire prefix.
525 	 * XXX: this change might affect some existing code base...
526 	 */
527 	bzero(&pr0, sizeof(pr0));
528 	pr0.ndpr_ifp = ifp;
529 	/* this should be 64 at this moment. */
530 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
531 	pr0.ndpr_prefix = ifra.ifra_addr;
532 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
533 	for (i = 0; i < 4; i++) {
534 		pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
535 		    in6mask64.s6_addr32[i];
536 	}
537 	/*
538 	 * Initialize parameters.  The link-local prefix must always be
539 	 * on-link, and its lifetimes never expire.
540 	 */
541 	pr0.ndpr_raf_onlink = 1;
542 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
543 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
544 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
545 	/*
546 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
547 	 * probably returns NULL.  However, we cannot always expect the result.
548 	 * For example, if we first remove the (only) existing link-local
549 	 * address, and then reconfigure another one, the prefix is still
550 	 * valid with referring to the old link-local address.
551 	 */
552 	if (nd6_prefix_lookup(&pr0) == NULL) {
553 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
554 			return (error);
555 	}
556 
557 	return 0;
558 }
559 
560 /*
561  * ifp - must be IFT_LOOP
562  */
563 static int
564 in6_ifattach_loopback(struct ifnet *ifp)
565 {
566 	struct in6_aliasreq ifra;
567 	int error;
568 
569 	bzero(&ifra, sizeof(ifra));
570 
571 	/*
572 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
573 	 * for safety.
574 	 */
575 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
576 
577 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
578 	ifra.ifra_prefixmask.sin6_family = AF_INET6;
579 	ifra.ifra_prefixmask.sin6_addr = in6mask128;
580 
581 	/*
582 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
583 	 * address.  Follows IPv4 practice - see in_ifinit().
584 	 */
585 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
586 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
587 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
588 
589 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
590 	ifra.ifra_addr.sin6_family = AF_INET6;
591 	ifra.ifra_addr.sin6_addr = in6addr_loopback;
592 
593 	/* the loopback  address should NEVER expire. */
594 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
595 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
596 
597 	/* we don't need to perform DAD on loopback interfaces. */
598 	ifra.ifra_flags |= IN6_IFF_NODAD;
599 
600 	/* skip registration to the prefix list. XXX should be temporary. */
601 	ifra.ifra_flags |= IN6_IFF_NOPFX;
602 
603 	/*
604 	 * We are sure that this is a newly assigned address, so we can set
605 	 * NULL to the 3rd arg.
606 	 */
607 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
608 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
609 		    "the loopback address on %s (errno=%d)\n",
610 		    if_name(ifp), error));
611 		return (-1);
612 	}
613 
614 	return 0;
615 }
616 
617 /*
618  * compute NI group address, based on the current hostname setting.
619  * see RFC 4620.
620  *
621  * when ifp == NULL, the caller is responsible for filling scopeid.
622  *
623  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
624  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
625  */
626 static int
627 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
628     struct in6_addr *in6, int oldmcprefix)
629 {
630 	struct prison *pr;
631 	const char *p;
632 	u_char *q;
633 	MD5_CTX ctxt;
634 	u_int8_t digest[16];
635 	char l;
636 	char n[64];	/* a single label must not exceed 63 chars */
637 
638 	/*
639 	 * If no name is given and namelen is -1,
640 	 * we try to do the hostname lookup ourselves.
641 	 */
642 	if (!name && namelen == -1) {
643 		pr = curthread->td_ucred->cr_prison;
644 		mtx_lock(&pr->pr_mtx);
645 		name = pr->pr_hostname;
646 		namelen = strlen(name);
647 	} else
648 		pr = NULL;
649 	if (!name || !namelen) {
650 		if (pr != NULL)
651 			mtx_unlock(&pr->pr_mtx);
652 		return -1;
653 	}
654 
655 	p = name;
656 	while (p && *p && *p != '.' && p - name < namelen)
657 		p++;
658 	if (p == name || p - name > sizeof(n) - 1) {
659 		if (pr != NULL)
660 			mtx_unlock(&pr->pr_mtx);
661 		return -1;	/* label too long */
662 	}
663 	l = p - name;
664 	strncpy(n, name, l);
665 	if (pr != NULL)
666 		mtx_unlock(&pr->pr_mtx);
667 	n[(int)l] = '\0';
668 	for (q = n; *q; q++) {
669 		if ('A' <= *q && *q <= 'Z')
670 			*q = *q - 'A' + 'a';
671 	}
672 
673 	/* generate 16 bytes of pseudo-random value. */
674 	bzero(&ctxt, sizeof(ctxt));
675 	MD5Init(&ctxt);
676 	MD5Update(&ctxt, &l, sizeof(l));
677 	MD5Update(&ctxt, n, l);
678 	MD5Final(digest, &ctxt);
679 
680 	bzero(in6, sizeof(*in6));
681 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
682 	in6->s6_addr8[11] = 2;
683 	if (oldmcprefix == 0) {
684 		in6->s6_addr8[12] = 0xff;
685 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
686 		bcopy(digest, &in6->s6_addr8[13], 3);
687 	} else {
688 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
689 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
690 	}
691 	if (in6_setscope(in6, ifp, NULL))
692 		return (-1); /* XXX: should not fail */
693 
694 	return 0;
695 }
696 
697 int
698 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
699     struct in6_addr *in6)
700 {
701 
702 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
703 }
704 
705 int
706 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
707     struct in6_addr *in6)
708 {
709 
710 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
711 }
712 
713 /*
714  * XXX multiple loopback interface needs more care.  for instance,
715  * nodelocal address needs to be configured onto only one of them.
716  * XXX multiple link-local address case
717  *
718  * altifp - secondary EUI64 source
719  */
720 void
721 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
722 {
723 	struct in6_ifaddr *ia;
724 	struct in6_addr in6;
725 
726 	/* some of the interfaces are inherently not IPv6 capable */
727 	switch (ifp->if_type) {
728 	case IFT_PFLOG:
729 	case IFT_PFSYNC:
730 		return;
731 	}
732 
733 	/*
734 	 * quirks based on interface type
735 	 */
736 	switch (ifp->if_type) {
737 #ifdef IFT_STF
738 	case IFT_STF:
739 		/*
740 		 * 6to4 interface is a very special kind of beast.
741 		 * no multicast, no linklocal.  RFC2529 specifies how to make
742 		 * linklocals for 6to4 interface, but there's no use and
743 		 * it is rather harmful to have one.
744 		 */
745 		goto statinit;
746 #endif
747 	default:
748 		break;
749 	}
750 
751 	/*
752 	 * usually, we require multicast capability to the interface
753 	 */
754 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
755 		nd6log((LOG_INFO, "in6_ifattach: "
756 		    "%s is not multicast capable, IPv6 not enabled\n",
757 		    if_name(ifp)));
758 		return;
759 	}
760 
761 	/*
762 	 * assign loopback address for loopback interface.
763 	 * XXX multiple loopback interface case.
764 	 */
765 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
766 		struct ifaddr *ifa;
767 
768 		in6 = in6addr_loopback;
769 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &in6);
770 		if (ifa == NULL) {
771 			if (in6_ifattach_loopback(ifp) != 0)
772 				return;
773 		} else
774 			ifa_free(ifa);
775 	}
776 
777 	/*
778 	 * assign a link-local address, if there's none.
779 	 */
780 	if (ifp->if_type != IFT_BRIDGE &&
781 	    !(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
782 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
783 		int error;
784 
785 		ia = in6ifa_ifpforlinklocal(ifp, 0);
786 		if (ia == NULL) {
787 			error = in6_ifattach_linklocal(ifp, altifp);
788 #if 0
789 			if (error)
790 				log(LOG_NOTICE, "in6_ifattach_linklocal: "
791 				    "failed to add a link-local addr to %s\n",
792 				    if_name(ifp));
793 #endif
794 		} else
795 			ifa_free(&ia->ia_ifa);
796 	}
797 
798 #ifdef IFT_STF			/* XXX */
799 statinit:
800 #endif
801 
802 	/* update dynamically. */
803 	if (V_in6_maxmtu < ifp->if_mtu)
804 		V_in6_maxmtu = ifp->if_mtu;
805 }
806 
807 /*
808  * NOTE: in6_ifdetach() does not support loopback if at this moment.
809  * We don't need this function in bsdi, because interfaces are never removed
810  * from the ifnet list in bsdi.
811  */
812 void
813 in6_ifdetach(struct ifnet *ifp)
814 {
815 	struct in6_ifaddr *ia;
816 	struct ifaddr *ifa, *next;
817 	struct radix_node_head *rnh;
818 	struct rtentry *rt;
819 	struct sockaddr_in6 sin6;
820 	struct in6_multi_mship *imm;
821 
822 	/* remove neighbor management table */
823 	nd6_purge(ifp);
824 
825 	/* nuke any of IPv6 addresses we have */
826 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
827 		if (ifa->ifa_addr->sa_family != AF_INET6)
828 			continue;
829 		in6_purgeaddr(ifa);
830 	}
831 
832 	/* undo everything done by in6_ifattach(), just in case */
833 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
834 		if (ifa->ifa_addr->sa_family != AF_INET6
835 		 || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
836 			continue;
837 		}
838 
839 		ia = (struct in6_ifaddr *)ifa;
840 
841 		/*
842 		 * leave from multicast groups we have joined for the interface
843 		 */
844 		while ((imm = LIST_FIRST(&ia->ia6_memberships)) != NULL) {
845 			LIST_REMOVE(imm, i6mm_chain);
846 			in6_leavegroup(imm);
847 		}
848 
849 		/* Remove link-local from the routing table. */
850 		if (ia->ia_flags & IFA_ROUTE)
851 			(void)rtinit(&ia->ia_ifa, RTM_DELETE, ia->ia_flags);
852 
853 		/* remove from the linked list */
854 		IF_ADDR_WLOCK(ifp);
855 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
856 		IF_ADDR_WUNLOCK(ifp);
857 		ifa_free(ifa);				/* if_addrhead */
858 
859 		IN6_IFADDR_WLOCK();
860 		TAILQ_REMOVE(&V_in6_ifaddrhead, ia, ia_link);
861 		IN6_IFADDR_WUNLOCK();
862 		ifa_free(ifa);
863 	}
864 
865 	in6_pcbpurgeif0(&V_udbinfo, ifp);
866 	in6_pcbpurgeif0(&V_ripcbinfo, ifp);
867 	/* leave from all multicast groups joined */
868 	in6_purgemaddrs(ifp);
869 
870 	/*
871 	 * remove neighbor management table.  we call it twice just to make
872 	 * sure we nuke everything.  maybe we need just one call.
873 	 * XXX: since the first call did not release addresses, some prefixes
874 	 * might remain.  We should call nd6_purge() again to release the
875 	 * prefixes after removing all addresses above.
876 	 * (Or can we just delay calling nd6_purge until at this point?)
877 	 */
878 	nd6_purge(ifp);
879 
880 	/*
881 	 * Remove route to link-local allnodes multicast (ff02::1).
882 	 * These only get automatically installed for the default FIB.
883 	 */
884 	bzero(&sin6, sizeof(sin6));
885 	sin6.sin6_len = sizeof(struct sockaddr_in6);
886 	sin6.sin6_family = AF_INET6;
887 	sin6.sin6_addr = in6addr_linklocal_allnodes;
888 	if (in6_setscope(&sin6.sin6_addr, ifp, NULL))
889 		/* XXX: should not fail */
890 		return;
891 	/* XXX grab lock first to avoid LOR */
892 	rnh = rt_tables_get_rnh(RT_DEFAULT_FIB, AF_INET6);
893 	if (rnh != NULL) {
894 		RADIX_NODE_HEAD_LOCK(rnh);
895 		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, RTF_RNH_LOCKED,
896 		    RT_DEFAULT_FIB);
897 		if (rt) {
898 			if (rt->rt_ifp == ifp)
899 				rtexpunge(rt);
900 			RTFREE_LOCKED(rt);
901 		}
902 		RADIX_NODE_HEAD_UNLOCK(rnh);
903 	}
904 }
905 
906 int
907 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
908     const u_int8_t *baseid, int generate)
909 {
910 	u_int8_t nullbuf[8];
911 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
912 
913 	bzero(nullbuf, sizeof(nullbuf));
914 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
915 		/* we've never created a random ID.  Create a new one. */
916 		generate = 1;
917 	}
918 
919 	if (generate) {
920 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
921 
922 		/* generate_tmp_ifid will update seedn and buf */
923 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
924 		    ndi->randomid);
925 	}
926 	bcopy(ndi->randomid, retbuf, 8);
927 
928 	return (0);
929 }
930 
931 void
932 in6_tmpaddrtimer(void *arg)
933 {
934 	CURVNET_SET((struct vnet *) arg);
935 	struct nd_ifinfo *ndi;
936 	u_int8_t nullbuf[8];
937 	struct ifnet *ifp;
938 
939 	callout_reset(&V_in6_tmpaddrtimer_ch,
940 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
941 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
942 
943 	bzero(nullbuf, sizeof(nullbuf));
944 	TAILQ_FOREACH(ifp, &V_ifnet, if_list) {
945 		ndi = ND_IFINFO(ifp);
946 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
947 			/*
948 			 * We've been generating a random ID on this interface.
949 			 * Create a new one.
950 			 */
951 			(void)generate_tmp_ifid(ndi->randomseed0,
952 			    ndi->randomseed1, ndi->randomid);
953 		}
954 	}
955 
956 	CURVNET_RESTORE();
957 }
958 
959 static void
960 in6_purgemaddrs(struct ifnet *ifp)
961 {
962 	LIST_HEAD(,in6_multi)	 purgeinms;
963 	struct in6_multi	*inm, *tinm;
964 	struct ifmultiaddr	*ifma;
965 
966 	LIST_INIT(&purgeinms);
967 	IN6_MULTI_LOCK();
968 
969 	/*
970 	 * Extract list of in6_multi associated with the detaching ifp
971 	 * which the PF_INET6 layer is about to release.
972 	 * We need to do this as IF_ADDR_LOCK() may be re-acquired
973 	 * by code further down.
974 	 */
975 	IF_ADDR_RLOCK(ifp);
976 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
977 		if (ifma->ifma_addr->sa_family != AF_INET6 ||
978 		    ifma->ifma_protospec == NULL)
979 			continue;
980 		inm = (struct in6_multi *)ifma->ifma_protospec;
981 		LIST_INSERT_HEAD(&purgeinms, inm, in6m_entry);
982 	}
983 	IF_ADDR_RUNLOCK(ifp);
984 
985 	LIST_FOREACH_SAFE(inm, &purgeinms, in6m_entry, tinm) {
986 		LIST_REMOVE(inm, in6m_entry);
987 		in6m_release_locked(inm);
988 	}
989 	mld_ifdetach(ifp);
990 
991 	IN6_MULTI_UNLOCK();
992 }
993