xref: /freebsd/sys/netinet6/in6_ifattach.c (revision aa64588d28258aef88cc33b8043112e8856948d0)
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_LOCK(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_UNLOCK(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_FDDI:
271 	case IFT_ISO88025:
272 	case IFT_ATM:
273 	case IFT_IEEE1394:
274 #ifdef IFT_IEEE80211
275 	case IFT_IEEE80211:
276 #endif
277 		/* IEEE802/EUI64 cases - what others? */
278 		/* IEEE1394 uses 16byte length address starting with EUI64 */
279 		if (addrlen > 8)
280 			addrlen = 8;
281 
282 		/* look at IEEE802/EUI64 only */
283 		if (addrlen != 8 && addrlen != 6) {
284 			IF_ADDR_UNLOCK(ifp);
285 			return -1;
286 		}
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 			IF_ADDR_UNLOCK(ifp);
295 			return -1;
296 		}
297 		if (bcmp(addr, allone, addrlen) == 0) {
298 			IF_ADDR_UNLOCK(ifp);
299 			return -1;
300 		}
301 
302 		/* make EUI64 address */
303 		if (addrlen == 8)
304 			bcopy(addr, &in6->s6_addr[8], 8);
305 		else if (addrlen == 6) {
306 			in6->s6_addr[8] = addr[0];
307 			in6->s6_addr[9] = addr[1];
308 			in6->s6_addr[10] = addr[2];
309 			in6->s6_addr[11] = 0xff;
310 			in6->s6_addr[12] = 0xfe;
311 			in6->s6_addr[13] = addr[3];
312 			in6->s6_addr[14] = addr[4];
313 			in6->s6_addr[15] = addr[5];
314 		}
315 		break;
316 
317 	case IFT_ARCNET:
318 		if (addrlen != 1) {
319 			IF_ADDR_UNLOCK(ifp);
320 			return -1;
321 		}
322 		if (!addr[0]) {
323 			IF_ADDR_UNLOCK(ifp);
324 			return -1;
325 		}
326 
327 		bzero(&in6->s6_addr[8], 8);
328 		in6->s6_addr[15] = addr[0];
329 
330 		/*
331 		 * due to insufficient bitwidth, we mark it local.
332 		 */
333 		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
334 		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
335 		break;
336 
337 	case IFT_GIF:
338 #ifdef IFT_STF
339 	case IFT_STF:
340 #endif
341 		/*
342 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
343 		 * however, IPv4 address is not very suitable as unique
344 		 * identifier source (can be renumbered).
345 		 * we don't do this.
346 		 */
347 		IF_ADDR_UNLOCK(ifp);
348 		return -1;
349 
350 	default:
351 		IF_ADDR_UNLOCK(ifp);
352 		return -1;
353 	}
354 
355 	/* sanity check: g bit must not indicate "group" */
356 	if (EUI64_GROUP(in6)) {
357 		IF_ADDR_UNLOCK(ifp);
358 		return -1;
359 	}
360 
361 	/* convert EUI64 into IPv6 interface identifier */
362 	EUI64_TO_IFID(in6);
363 
364 	/*
365 	 * sanity check: ifid must not be all zero, avoid conflict with
366 	 * subnet router anycast
367 	 */
368 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
369 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
370 		IF_ADDR_UNLOCK(ifp);
371 		return -1;
372 	}
373 
374 	IF_ADDR_UNLOCK(ifp);
375 	return 0;
376 }
377 
378 /*
379  * Get interface identifier for the specified interface.  If it is not
380  * available on ifp0, borrow interface identifier from other information
381  * sources.
382  *
383  * altifp - secondary EUI64 source
384  */
385 static int
386 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
387     struct in6_addr *in6)
388 {
389 	struct ifnet *ifp;
390 
391 	/* first, try to get it from the interface itself */
392 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
393 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
394 		    if_name(ifp0)));
395 		goto success;
396 	}
397 
398 	/* try secondary EUI64 source. this basically is for ATM PVC */
399 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
400 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
401 		    if_name(ifp0), if_name(altifp)));
402 		goto success;
403 	}
404 
405 	/* next, try to get it from some other hardware interface */
406 	IFNET_RLOCK_NOSLEEP();
407 	for (ifp = V_ifnet.tqh_first; ifp; ifp = ifp->if_list.tqe_next) {
408 		if (ifp == ifp0)
409 			continue;
410 		if (in6_get_hw_ifid(ifp, in6) != 0)
411 			continue;
412 
413 		/*
414 		 * to borrow ifid from other interface, ifid needs to be
415 		 * globally unique
416 		 */
417 		if (IFID_UNIVERSAL(in6)) {
418 			nd6log((LOG_DEBUG,
419 			    "%s: borrow interface identifier from %s\n",
420 			    if_name(ifp0), if_name(ifp)));
421 			IFNET_RUNLOCK_NOSLEEP();
422 			goto success;
423 		}
424 	}
425 	IFNET_RUNLOCK_NOSLEEP();
426 
427 	/* last resort: get from random number source */
428 	if (get_rand_ifid(ifp, in6) == 0) {
429 		nd6log((LOG_DEBUG,
430 		    "%s: interface identifier generated by random number\n",
431 		    if_name(ifp0)));
432 		goto success;
433 	}
434 
435 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
436 	return -1;
437 
438 success:
439 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
440 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
441 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
442 	    in6->s6_addr[14], in6->s6_addr[15]));
443 	return 0;
444 }
445 
446 /*
447  * altifp - secondary EUI64 source
448  */
449 static int
450 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
451 {
452 	struct in6_ifaddr *ia;
453 	struct in6_aliasreq ifra;
454 	struct nd_prefixctl pr0;
455 	int i, error;
456 
457 	/*
458 	 * configure link-local address.
459 	 */
460 	bzero(&ifra, sizeof(ifra));
461 
462 	/*
463 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
464 	 * for safety.
465 	 */
466 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
467 
468 	ifra.ifra_addr.sin6_family = AF_INET6;
469 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
470 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
471 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
472 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
473 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
474 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
475 	} else {
476 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
477 			nd6log((LOG_ERR,
478 			    "%s: no ifid available\n", if_name(ifp)));
479 			return (-1);
480 		}
481 	}
482 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
483 		return (-1);
484 
485 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
486 	ifra.ifra_prefixmask.sin6_family = AF_INET6;
487 	ifra.ifra_prefixmask.sin6_addr = in6mask64;
488 	/* link-local addresses should NEVER expire. */
489 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
490 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
491 
492 	/*
493 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
494 	 * a link-local address. We can set the 3rd argument to NULL, because
495 	 * we know there's no other link-local address on the interface
496 	 * and therefore we are adding one (instead of updating one).
497 	 */
498 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
499 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
500 		/*
501 		 * XXX: When the interface does not support IPv6, this call
502 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
503 		 * notification is rather confusing in this case, so just
504 		 * suppress it.  (jinmei@kame.net 20010130)
505 		 */
506 		if (error != EAFNOSUPPORT)
507 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
508 			    "configure a link-local address on %s "
509 			    "(errno=%d)\n",
510 			    if_name(ifp), error));
511 		return (-1);
512 	}
513 
514 	ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
515 #ifdef DIAGNOSTIC
516 	if (!ia) {
517 		panic("ia == NULL in in6_ifattach_linklocal");
518 		/* NOTREACHED */
519 	}
520 #endif
521 	ifa_free(&ia->ia_ifa);
522 
523 	/*
524 	 * Make the link-local prefix (fe80::%link/64) as on-link.
525 	 * Since we'd like to manage prefixes separately from addresses,
526 	 * we make an ND6 prefix structure for the link-local prefix,
527 	 * and add it to the prefix list as a never-expire prefix.
528 	 * XXX: this change might affect some existing code base...
529 	 */
530 	bzero(&pr0, sizeof(pr0));
531 	pr0.ndpr_ifp = ifp;
532 	/* this should be 64 at this moment. */
533 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
534 	pr0.ndpr_prefix = ifra.ifra_addr;
535 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
536 	for (i = 0; i < 4; i++) {
537 		pr0.ndpr_prefix.sin6_addr.s6_addr32[i] &=
538 		    in6mask64.s6_addr32[i];
539 	}
540 	/*
541 	 * Initialize parameters.  The link-local prefix must always be
542 	 * on-link, and its lifetimes never expire.
543 	 */
544 	pr0.ndpr_raf_onlink = 1;
545 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
546 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
547 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
548 	/*
549 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
550 	 * probably returns NULL.  However, we cannot always expect the result.
551 	 * For example, if we first remove the (only) existing link-local
552 	 * address, and then reconfigure another one, the prefix is still
553 	 * valid with referring to the old link-local address.
554 	 */
555 	if (nd6_prefix_lookup(&pr0) == NULL) {
556 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
557 			return (error);
558 	}
559 
560 	return 0;
561 }
562 
563 /*
564  * ifp - must be IFT_LOOP
565  */
566 static int
567 in6_ifattach_loopback(struct ifnet *ifp)
568 {
569 	struct in6_aliasreq ifra;
570 	int error;
571 
572 	bzero(&ifra, sizeof(ifra));
573 
574 	/*
575 	 * in6_update_ifa() does not use ifra_name, but we accurately set it
576 	 * for safety.
577 	 */
578 	strncpy(ifra.ifra_name, if_name(ifp), sizeof(ifra.ifra_name));
579 
580 	ifra.ifra_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
581 	ifra.ifra_prefixmask.sin6_family = AF_INET6;
582 	ifra.ifra_prefixmask.sin6_addr = in6mask128;
583 
584 	/*
585 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
586 	 * address.  Follows IPv4 practice - see in_ifinit().
587 	 */
588 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
589 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
590 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
591 
592 	ifra.ifra_addr.sin6_len = sizeof(struct sockaddr_in6);
593 	ifra.ifra_addr.sin6_family = AF_INET6;
594 	ifra.ifra_addr.sin6_addr = in6addr_loopback;
595 
596 	/* the loopback  address should NEVER expire. */
597 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
598 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
599 
600 	/* we don't need to perform DAD on loopback interfaces. */
601 	ifra.ifra_flags |= IN6_IFF_NODAD;
602 
603 	/* skip registration to the prefix list. XXX should be temporary. */
604 	ifra.ifra_flags |= IN6_IFF_NOPFX;
605 
606 	/*
607 	 * We are sure that this is a newly assigned address, so we can set
608 	 * NULL to the 3rd arg.
609 	 */
610 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
611 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
612 		    "the loopback address on %s (errno=%d)\n",
613 		    if_name(ifp), error));
614 		return (-1);
615 	}
616 
617 	return 0;
618 }
619 
620 /*
621  * compute NI group address, based on the current hostname setting.
622  * see draft-ietf-ipngwg-icmp-name-lookup-* (04 and later).
623  *
624  * when ifp == NULL, the caller is responsible for filling scopeid.
625  */
626 int
627 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
628     struct in6_addr *in6)
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 8 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 	bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
684 	if (in6_setscope(in6, ifp, NULL))
685 		return (-1); /* XXX: should not fail */
686 
687 	return 0;
688 }
689 
690 /*
691  * XXX multiple loopback interface needs more care.  for instance,
692  * nodelocal address needs to be configured onto only one of them.
693  * XXX multiple link-local address case
694  *
695  * altifp - secondary EUI64 source
696  */
697 void
698 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
699 {
700 	struct in6_ifaddr *ia;
701 	struct in6_addr in6;
702 
703 	/* some of the interfaces are inherently not IPv6 capable */
704 	switch (ifp->if_type) {
705 	case IFT_PFLOG:
706 	case IFT_PFSYNC:
707 	case IFT_CARP:
708 		return;
709 	}
710 
711 	/*
712 	 * quirks based on interface type
713 	 */
714 	switch (ifp->if_type) {
715 #ifdef IFT_STF
716 	case IFT_STF:
717 		/*
718 		 * 6to4 interface is a very special kind of beast.
719 		 * no multicast, no linklocal.  RFC2529 specifies how to make
720 		 * linklocals for 6to4 interface, but there's no use and
721 		 * it is rather harmful to have one.
722 		 */
723 		goto statinit;
724 #endif
725 	default:
726 		break;
727 	}
728 
729 	/*
730 	 * usually, we require multicast capability to the interface
731 	 */
732 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
733 		nd6log((LOG_INFO, "in6_ifattach: "
734 		    "%s is not multicast capable, IPv6 not enabled\n",
735 		    if_name(ifp)));
736 		return;
737 	}
738 
739 	/*
740 	 * assign loopback address for loopback interface.
741 	 * XXX multiple loopback interface case.
742 	 */
743 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
744 		struct ifaddr *ifa;
745 
746 		in6 = in6addr_loopback;
747 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &in6);
748 		if (ifa == NULL) {
749 			if (in6_ifattach_loopback(ifp) != 0)
750 				return;
751 		} else
752 			ifa_free(ifa);
753 	}
754 
755 	/*
756 	 * assign a link-local address, if there's none.
757 	 */
758 	if (ifp->if_type != IFT_BRIDGE &&
759 	    !(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
760 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
761 		int error;
762 
763 		ia = in6ifa_ifpforlinklocal(ifp, 0);
764 		if (ia == NULL) {
765 			error = in6_ifattach_linklocal(ifp, altifp);
766 #if 0
767 			if (error)
768 				log(LOG_NOTICE, "in6_ifattach_linklocal: "
769 				    "failed to add a link-local addr to %s\n",
770 				    if_name(ifp));
771 #endif
772 		} else
773 			ifa_free(&ia->ia_ifa);
774 	}
775 
776 #ifdef IFT_STF			/* XXX */
777 statinit:
778 #endif
779 
780 	/* update dynamically. */
781 	if (V_in6_maxmtu < ifp->if_mtu)
782 		V_in6_maxmtu = ifp->if_mtu;
783 }
784 
785 /*
786  * NOTE: in6_ifdetach() does not support loopback if at this moment.
787  * We don't need this function in bsdi, because interfaces are never removed
788  * from the ifnet list in bsdi.
789  */
790 void
791 in6_ifdetach(struct ifnet *ifp)
792 {
793 	struct in6_ifaddr *ia;
794 	struct ifaddr *ifa, *next;
795 	struct radix_node_head *rnh;
796 	struct rtentry *rt;
797 	short rtflags;
798 	struct sockaddr_in6 sin6;
799 	struct in6_multi_mship *imm;
800 
801 	/* remove neighbor management table */
802 	nd6_purge(ifp);
803 
804 	/* nuke any of IPv6 addresses we have */
805 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
806 		if (ifa->ifa_addr->sa_family != AF_INET6)
807 			continue;
808 		in6_purgeaddr(ifa);
809 	}
810 
811 	/* undo everything done by in6_ifattach(), just in case */
812 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
813 		if (ifa->ifa_addr->sa_family != AF_INET6
814 		 || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
815 			continue;
816 		}
817 
818 		ia = (struct in6_ifaddr *)ifa;
819 
820 		/*
821 		 * leave from multicast groups we have joined for the interface
822 		 */
823 		while ((imm = ia->ia6_memberships.lh_first) != NULL) {
824 			LIST_REMOVE(imm, i6mm_chain);
825 			in6_leavegroup(imm);
826 		}
827 
828 		/* remove from the routing table */
829 		if ((ia->ia_flags & IFA_ROUTE) &&
830 		    (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0, 0UL))) {
831 			rtflags = rt->rt_flags;
832 			RTFREE_LOCKED(rt);
833 			rtrequest(RTM_DELETE, (struct sockaddr *)&ia->ia_addr,
834 			    (struct sockaddr *)&ia->ia_addr,
835 			    (struct sockaddr *)&ia->ia_prefixmask,
836 			    rtflags, (struct rtentry **)0);
837 		}
838 
839 		/* remove from the linked list */
840 		IF_ADDR_LOCK(ifp);
841 		TAILQ_REMOVE(&ifp->if_addrhead, ifa, ifa_link);
842 		IF_ADDR_UNLOCK(ifp);
843 		ifa_free(ifa);				/* if_addrhead */
844 
845 		IN6_IFADDR_WLOCK();
846 		TAILQ_REMOVE(&V_in6_ifaddrhead, ia, ia_link);
847 		IN6_IFADDR_WUNLOCK();
848 		ifa_free(ifa);
849 	}
850 
851 	in6_pcbpurgeif0(&V_udbinfo, ifp);
852 	in6_pcbpurgeif0(&V_ripcbinfo, ifp);
853 	/* leave from all multicast groups joined */
854 	in6_purgemaddrs(ifp);
855 
856 	/*
857 	 * remove neighbor management table.  we call it twice just to make
858 	 * sure we nuke everything.  maybe we need just one call.
859 	 * XXX: since the first call did not release addresses, some prefixes
860 	 * might remain.  We should call nd6_purge() again to release the
861 	 * prefixes after removing all addresses above.
862 	 * (Or can we just delay calling nd6_purge until at this point?)
863 	 */
864 	nd6_purge(ifp);
865 
866 	/* remove route to link-local allnodes multicast (ff02::1) */
867 	bzero(&sin6, sizeof(sin6));
868 	sin6.sin6_len = sizeof(struct sockaddr_in6);
869 	sin6.sin6_family = AF_INET6;
870 	sin6.sin6_addr = in6addr_linklocal_allnodes;
871 	if (in6_setscope(&sin6.sin6_addr, ifp, NULL))
872 		/* XXX: should not fail */
873 		return;
874 	/* XXX grab lock first to avoid LOR */
875 	rnh = rt_tables_get_rnh(0, AF_INET6);
876 	if (rnh != NULL) {
877 		RADIX_NODE_HEAD_LOCK(rnh);
878 		rt = rtalloc1((struct sockaddr *)&sin6, 0, RTF_RNH_LOCKED);
879 		if (rt) {
880 			if (rt->rt_ifp == ifp)
881 				rtexpunge(rt);
882 			RTFREE_LOCKED(rt);
883 		}
884 		RADIX_NODE_HEAD_UNLOCK(rnh);
885 	}
886 }
887 
888 int
889 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
890     const u_int8_t *baseid, int generate)
891 {
892 	u_int8_t nullbuf[8];
893 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
894 
895 	bzero(nullbuf, sizeof(nullbuf));
896 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
897 		/* we've never created a random ID.  Create a new one. */
898 		generate = 1;
899 	}
900 
901 	if (generate) {
902 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
903 
904 		/* generate_tmp_ifid will update seedn and buf */
905 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
906 		    ndi->randomid);
907 	}
908 	bcopy(ndi->randomid, retbuf, 8);
909 
910 	return (0);
911 }
912 
913 void
914 in6_tmpaddrtimer(void *arg)
915 {
916 	CURVNET_SET((struct vnet *) arg);
917 	struct nd_ifinfo *ndi;
918 	u_int8_t nullbuf[8];
919 	struct ifnet *ifp;
920 
921 	callout_reset(&V_in6_tmpaddrtimer_ch,
922 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
923 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
924 
925 	bzero(nullbuf, sizeof(nullbuf));
926 	for (ifp = TAILQ_FIRST(&V_ifnet); ifp;
927 	    ifp = TAILQ_NEXT(ifp, if_list)) {
928 		ndi = ND_IFINFO(ifp);
929 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
930 			/*
931 			 * We've been generating a random ID on this interface.
932 			 * Create a new one.
933 			 */
934 			(void)generate_tmp_ifid(ndi->randomseed0,
935 			    ndi->randomseed1, ndi->randomid);
936 		}
937 	}
938 
939 	CURVNET_RESTORE();
940 }
941 
942 static void
943 in6_purgemaddrs(struct ifnet *ifp)
944 {
945 	LIST_HEAD(,in6_multi)	 purgeinms;
946 	struct in6_multi	*inm, *tinm;
947 	struct ifmultiaddr	*ifma;
948 
949 	LIST_INIT(&purgeinms);
950 	IN6_MULTI_LOCK();
951 
952 	/*
953 	 * Extract list of in6_multi associated with the detaching ifp
954 	 * which the PF_INET6 layer is about to release.
955 	 * We need to do this as IF_ADDR_LOCK() may be re-acquired
956 	 * by code further down.
957 	 */
958 	IF_ADDR_LOCK(ifp);
959 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
960 		if (ifma->ifma_addr->sa_family != AF_INET6 ||
961 		    ifma->ifma_protospec == NULL)
962 			continue;
963 		inm = (struct in6_multi *)ifma->ifma_protospec;
964 		LIST_INSERT_HEAD(&purgeinms, inm, in6m_entry);
965 	}
966 	IF_ADDR_UNLOCK(ifp);
967 
968 	LIST_FOREACH_SAFE(inm, &purgeinms, in6m_entry, tinm) {
969 		LIST_REMOVE(inm, in6m_entry);
970 		in6m_release_locked(inm);
971 	}
972 	mld_ifdetach(ifp);
973 
974 	IN6_MULTI_UNLOCK();
975 }
976