xref: /freebsd/sys/netinet6/in6_ifattach.c (revision e8e8c939350bdf3c228a411caa9660c607c27a11)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: in6_ifattach.c,v 1.118 2001/05/24 07:44:00 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/malloc.h>
38 #include <sys/socket.h>
39 #include <sys/sockio.h>
40 #include <sys/jail.h>
41 #include <sys/kernel.h>
42 #include <sys/proc.h>
43 #include <sys/syslog.h>
44 #include <sys/md5.h>
45 
46 #include <net/if.h>
47 #include <net/if_var.h>
48 #include <net/if_dl.h>
49 #include <net/if_types.h>
50 #include <net/route.h>
51 #include <net/vnet.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_var.h>
55 #include <netinet/if_ether.h>
56 #include <netinet/in_pcb.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/udp.h>
59 #include <netinet/udp_var.h>
60 
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet6/in6_var.h>
64 #include <netinet6/in6_pcb.h>
65 #include <netinet6/in6_ifattach.h>
66 #include <netinet6/ip6_var.h>
67 #include <netinet6/nd6.h>
68 #include <netinet6/mld6_var.h>
69 #include <netinet6/scope6_var.h>
70 
71 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
72 
73 #ifdef IP6_AUTO_LINKLOCAL
74 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
75 #else
76 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
77 #endif
78 
79 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
80 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
81 
82 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
83 #define	V_ripcbinfo			VNET(ripcbinfo)
84 
85 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
86 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
87 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
88 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
89 static int in6_ifattach_loopback(struct ifnet *);
90 static void in6_purgemaddrs(struct ifnet *);
91 
92 #define EUI64_GBIT	0x01
93 #define EUI64_UBIT	0x02
94 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
95 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
96 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
97 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
98 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
99 
100 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
101 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
102 
103 /*
104  * Generate a last-resort interface identifier, when the machine has no
105  * IEEE802/EUI64 address sources.
106  * The goal here is to get an interface identifier that is
107  * (1) random enough and (2) does not change across reboot.
108  * We currently use MD5(hostname) for it.
109  *
110  * in6 - upper 64bits are preserved
111  */
112 static int
113 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
114 {
115 	MD5_CTX ctxt;
116 	struct prison *pr;
117 	u_int8_t digest[16];
118 	int hostnamelen;
119 
120 	pr = curthread->td_ucred->cr_prison;
121 	mtx_lock(&pr->pr_mtx);
122 	hostnamelen = strlen(pr->pr_hostname);
123 #if 0
124 	/* we need at least several letters as seed for ifid */
125 	if (hostnamelen < 3) {
126 		mtx_unlock(&pr->pr_mtx);
127 		return -1;
128 	}
129 #endif
130 
131 	/* generate 8 bytes of pseudo-random value. */
132 	bzero(&ctxt, sizeof(ctxt));
133 	MD5Init(&ctxt);
134 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
135 	mtx_unlock(&pr->pr_mtx);
136 	MD5Final(digest, &ctxt);
137 
138 	/* assumes sizeof(digest) > sizeof(ifid) */
139 	bcopy(digest, &in6->s6_addr[8], 8);
140 
141 	/* make sure to set "u" bit to local, and "g" bit to individual. */
142 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
143 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
144 
145 	/* convert EUI64 into IPv6 interface identifier */
146 	EUI64_TO_IFID(in6);
147 
148 	return 0;
149 }
150 
151 static int
152 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
153 {
154 	MD5_CTX ctxt;
155 	u_int8_t seed[16], digest[16], nullbuf[8];
156 	u_int32_t val32;
157 
158 	/* If there's no history, start with a random seed. */
159 	bzero(nullbuf, sizeof(nullbuf));
160 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
161 		int i;
162 
163 		for (i = 0; i < 2; i++) {
164 			val32 = arc4random();
165 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
166 		}
167 	} else
168 		bcopy(seed0, seed, 8);
169 
170 	/* copy the right-most 64-bits of the given address */
171 	/* XXX assumption on the size of IFID */
172 	bcopy(seed1, &seed[8], 8);
173 
174 	if (0) {		/* for debugging purposes only */
175 		int i;
176 
177 		printf("generate_tmp_ifid: new randomized ID from: ");
178 		for (i = 0; i < 16; i++)
179 			printf("%02x", seed[i]);
180 		printf(" ");
181 	}
182 
183 	/* generate 16 bytes of pseudo-random value. */
184 	bzero(&ctxt, sizeof(ctxt));
185 	MD5Init(&ctxt);
186 	MD5Update(&ctxt, seed, sizeof(seed));
187 	MD5Final(digest, &ctxt);
188 
189 	/*
190 	 * RFC 3041 3.2.1. (3)
191 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
192 	 * left-most bit is numbered 0) to zero.
193 	 */
194 	bcopy(digest, ret, 8);
195 	ret[0] &= ~EUI64_UBIT;
196 
197 	/*
198 	 * XXX: we'd like to ensure that the generated value is not zero
199 	 * for simplicity.  If the caclculated digest happens to be zero,
200 	 * use a random non-zero value as the last resort.
201 	 */
202 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
203 		nd6log((LOG_INFO,
204 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
205 
206 		val32 = arc4random();
207 		val32 = 1 + (val32 % (0xffffffff - 1));
208 	}
209 
210 	/*
211 	 * RFC 3041 3.2.1. (4)
212 	 * Take the rightmost 64-bits of the MD5 digest and save them in
213 	 * stable storage as the history value to be used in the next
214 	 * iteration of the algorithm.
215 	 */
216 	bcopy(&digest[8], seed0, 8);
217 
218 	if (0) {		/* for debugging purposes only */
219 		int i;
220 
221 		printf("to: ");
222 		for (i = 0; i < 16; i++)
223 			printf("%02x", digest[i]);
224 		printf("\n");
225 	}
226 
227 	return 0;
228 }
229 
230 /*
231  * Get interface identifier for the specified interface.
232  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
233  *
234  * in6 - upper 64bits are preserved
235  */
236 int
237 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
238 {
239 	struct ifaddr *ifa;
240 	struct sockaddr_dl *sdl;
241 	u_int8_t *addr;
242 	size_t addrlen;
243 	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
244 	static u_int8_t allone[8] =
245 		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
246 
247 	IF_ADDR_RLOCK(ifp);
248 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
249 		if (ifa->ifa_addr->sa_family != AF_LINK)
250 			continue;
251 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
252 		if (sdl == NULL)
253 			continue;
254 		if (sdl->sdl_alen == 0)
255 			continue;
256 
257 		goto found;
258 	}
259 	IF_ADDR_RUNLOCK(ifp);
260 
261 	return -1;
262 
263 found:
264 	IF_ADDR_LOCK_ASSERT(ifp);
265 	addr = LLADDR(sdl);
266 	addrlen = sdl->sdl_alen;
267 
268 	/* get EUI64 */
269 	switch (ifp->if_type) {
270 	case IFT_BRIDGE:
271 	case IFT_ETHER:
272 	case IFT_L2VLAN:
273 	case IFT_FDDI:
274 	case IFT_ISO88025:
275 	case IFT_ATM:
276 	case IFT_IEEE1394:
277 	case IFT_IEEE80211:
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 	case IFT_STF:
340 		/*
341 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
342 		 * however, IPv4 address is not very suitable as unique
343 		 * identifier source (can be renumbered).
344 		 * we don't do this.
345 		 */
346 		IF_ADDR_RUNLOCK(ifp);
347 		return -1;
348 
349 	default:
350 		IF_ADDR_RUNLOCK(ifp);
351 		return -1;
352 	}
353 
354 	/* sanity check: g bit must not indicate "group" */
355 	if (EUI64_GROUP(in6)) {
356 		IF_ADDR_RUNLOCK(ifp);
357 		return -1;
358 	}
359 
360 	/* convert EUI64 into IPv6 interface identifier */
361 	EUI64_TO_IFID(in6);
362 
363 	/*
364 	 * sanity check: ifid must not be all zero, avoid conflict with
365 	 * subnet router anycast
366 	 */
367 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
368 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
369 		IF_ADDR_RUNLOCK(ifp);
370 		return -1;
371 	}
372 
373 	IF_ADDR_RUNLOCK(ifp);
374 	return 0;
375 }
376 
377 /*
378  * Get interface identifier for the specified interface.  If it is not
379  * available on ifp0, borrow interface identifier from other information
380  * sources.
381  *
382  * altifp - secondary EUI64 source
383  */
384 static int
385 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
386     struct in6_addr *in6)
387 {
388 	struct ifnet *ifp;
389 
390 	/* first, try to get it from the interface itself */
391 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
392 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
393 		    if_name(ifp0)));
394 		goto success;
395 	}
396 
397 	/* try secondary EUI64 source. this basically is for ATM PVC */
398 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
399 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
400 		    if_name(ifp0), if_name(altifp)));
401 		goto success;
402 	}
403 
404 	/* next, try to get it from some other hardware interface */
405 	IFNET_RLOCK_NOSLEEP();
406 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
407 		if (ifp == ifp0)
408 			continue;
409 		if (in6_get_hw_ifid(ifp, in6) != 0)
410 			continue;
411 
412 		/*
413 		 * to borrow ifid from other interface, ifid needs to be
414 		 * globally unique
415 		 */
416 		if (IFID_UNIVERSAL(in6)) {
417 			nd6log((LOG_DEBUG,
418 			    "%s: borrow interface identifier from %s\n",
419 			    if_name(ifp0), if_name(ifp)));
420 			IFNET_RUNLOCK_NOSLEEP();
421 			goto success;
422 		}
423 	}
424 	IFNET_RUNLOCK_NOSLEEP();
425 
426 	/* last resort: get from random number source */
427 	if (get_rand_ifid(ifp, in6) == 0) {
428 		nd6log((LOG_DEBUG,
429 		    "%s: interface identifier generated by random number\n",
430 		    if_name(ifp0)));
431 		goto success;
432 	}
433 
434 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
435 	return -1;
436 
437 success:
438 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
439 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
440 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
441 	    in6->s6_addr[14], in6->s6_addr[15]));
442 	return 0;
443 }
444 
445 /*
446  * altifp - secondary EUI64 source
447  */
448 static int
449 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
450 {
451 	struct in6_ifaddr *ia;
452 	struct in6_aliasreq ifra;
453 	struct nd_prefixctl pr0;
454 	int error;
455 
456 	/*
457 	 * configure link-local address.
458 	 */
459 	in6_prepare_ifra(&ifra, NULL, &in6mask64);
460 
461 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
462 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
463 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
464 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
465 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
466 	} else {
467 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
468 			nd6log((LOG_ERR,
469 			    "%s: no ifid available\n", if_name(ifp)));
470 			return (-1);
471 		}
472 	}
473 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
474 		return (-1);
475 
476 	/* link-local addresses should NEVER expire. */
477 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
478 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
479 
480 	/*
481 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
482 	 * a link-local address. We can set the 3rd argument to NULL, because
483 	 * we know there's no other link-local address on the interface
484 	 * and therefore we are adding one (instead of updating one).
485 	 */
486 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
487 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
488 		/*
489 		 * XXX: When the interface does not support IPv6, this call
490 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
491 		 * notification is rather confusing in this case, so just
492 		 * suppress it.  (jinmei@kame.net 20010130)
493 		 */
494 		if (error != EAFNOSUPPORT)
495 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
496 			    "configure a link-local address on %s "
497 			    "(errno=%d)\n",
498 			    if_name(ifp), error));
499 		return (-1);
500 	}
501 
502 	ia = in6ifa_ifpforlinklocal(ifp, 0); /* ia must not be NULL */
503 	KASSERT(ia != NULL, ("%s: ia == NULL, ifp=%p", __func__, ifp));
504 
505 	ifa_free(&ia->ia_ifa);
506 
507 	/*
508 	 * Make the link-local prefix (fe80::%link/64) as on-link.
509 	 * Since we'd like to manage prefixes separately from addresses,
510 	 * we make an ND6 prefix structure for the link-local prefix,
511 	 * and add it to the prefix list as a never-expire prefix.
512 	 * XXX: this change might affect some existing code base...
513 	 */
514 	bzero(&pr0, sizeof(pr0));
515 	pr0.ndpr_ifp = ifp;
516 	/* this should be 64 at this moment. */
517 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
518 	pr0.ndpr_prefix = ifra.ifra_addr;
519 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
520 	IN6_MASK_ADDR(&pr0.ndpr_prefix.sin6_addr, &in6mask64);
521 	/*
522 	 * Initialize parameters.  The link-local prefix must always be
523 	 * on-link, and its lifetimes never expire.
524 	 */
525 	pr0.ndpr_raf_onlink = 1;
526 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
527 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
528 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
529 	/*
530 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
531 	 * probably returns NULL.  However, we cannot always expect the result.
532 	 * For example, if we first remove the (only) existing link-local
533 	 * address, and then reconfigure another one, the prefix is still
534 	 * valid with referring to the old link-local address.
535 	 */
536 	if (nd6_prefix_lookup(&pr0) == NULL) {
537 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
538 			return (error);
539 	}
540 
541 	return 0;
542 }
543 
544 /*
545  * ifp - must be IFT_LOOP
546  */
547 static int
548 in6_ifattach_loopback(struct ifnet *ifp)
549 {
550 	struct in6_aliasreq ifra;
551 	int error;
552 
553 	in6_prepare_ifra(&ifra, &in6addr_loopback, &in6mask128);
554 
555 	/*
556 	 * Always initialize ia_dstaddr (= broadcast address) to loopback
557 	 * address.  Follows IPv4 practice - see in_ifinit().
558 	 */
559 	ifra.ifra_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
560 	ifra.ifra_dstaddr.sin6_family = AF_INET6;
561 	ifra.ifra_dstaddr.sin6_addr = in6addr_loopback;
562 
563 	/* the loopback  address should NEVER expire. */
564 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
565 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
566 
567 	/* we don't need to perform DAD on loopback interfaces. */
568 	ifra.ifra_flags |= IN6_IFF_NODAD;
569 
570 	/* skip registration to the prefix list. XXX should be temporary. */
571 	ifra.ifra_flags |= IN6_IFF_NOPFX;
572 
573 	/*
574 	 * We are sure that this is a newly assigned address, so we can set
575 	 * NULL to the 3rd arg.
576 	 */
577 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
578 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
579 		    "the loopback address on %s (errno=%d)\n",
580 		    if_name(ifp), error));
581 		return (-1);
582 	}
583 
584 	return 0;
585 }
586 
587 /*
588  * compute NI group address, based on the current hostname setting.
589  * see RFC 4620.
590  *
591  * when ifp == NULL, the caller is responsible for filling scopeid.
592  *
593  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
594  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
595  */
596 static int
597 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
598     struct in6_addr *in6, int oldmcprefix)
599 {
600 	struct prison *pr;
601 	const char *p;
602 	u_char *q;
603 	MD5_CTX ctxt;
604 	u_int8_t digest[16];
605 	char l;
606 	char n[64];	/* a single label must not exceed 63 chars */
607 
608 	/*
609 	 * If no name is given and namelen is -1,
610 	 * we try to do the hostname lookup ourselves.
611 	 */
612 	if (!name && namelen == -1) {
613 		pr = curthread->td_ucred->cr_prison;
614 		mtx_lock(&pr->pr_mtx);
615 		name = pr->pr_hostname;
616 		namelen = strlen(name);
617 	} else
618 		pr = NULL;
619 	if (!name || !namelen) {
620 		if (pr != NULL)
621 			mtx_unlock(&pr->pr_mtx);
622 		return -1;
623 	}
624 
625 	p = name;
626 	while (p && *p && *p != '.' && p - name < namelen)
627 		p++;
628 	if (p == name || p - name > sizeof(n) - 1) {
629 		if (pr != NULL)
630 			mtx_unlock(&pr->pr_mtx);
631 		return -1;	/* label too long */
632 	}
633 	l = p - name;
634 	strncpy(n, name, l);
635 	if (pr != NULL)
636 		mtx_unlock(&pr->pr_mtx);
637 	n[(int)l] = '\0';
638 	for (q = n; *q; q++) {
639 		if ('A' <= *q && *q <= 'Z')
640 			*q = *q - 'A' + 'a';
641 	}
642 
643 	/* generate 16 bytes of pseudo-random value. */
644 	bzero(&ctxt, sizeof(ctxt));
645 	MD5Init(&ctxt);
646 	MD5Update(&ctxt, &l, sizeof(l));
647 	MD5Update(&ctxt, n, l);
648 	MD5Final(digest, &ctxt);
649 
650 	bzero(in6, sizeof(*in6));
651 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
652 	in6->s6_addr8[11] = 2;
653 	if (oldmcprefix == 0) {
654 		in6->s6_addr8[12] = 0xff;
655 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
656 		bcopy(digest, &in6->s6_addr8[13], 3);
657 	} else {
658 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
659 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
660 	}
661 	if (in6_setscope(in6, ifp, NULL))
662 		return (-1); /* XXX: should not fail */
663 
664 	return 0;
665 }
666 
667 int
668 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
669     struct in6_addr *in6)
670 {
671 
672 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
673 }
674 
675 int
676 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
677     struct in6_addr *in6)
678 {
679 
680 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
681 }
682 
683 /*
684  * XXX multiple loopback interface needs more care.  for instance,
685  * nodelocal address needs to be configured onto only one of them.
686  * XXX multiple link-local address case
687  *
688  * altifp - secondary EUI64 source
689  */
690 void
691 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
692 {
693 	struct in6_ifaddr *ia;
694 	struct in6_addr in6;
695 
696 	if (ifp->if_afdata[AF_INET6] == NULL)
697 		return;
698 	/*
699 	 * quirks based on interface type
700 	 */
701 	switch (ifp->if_type) {
702 	case IFT_STF:
703 		/*
704 		 * 6to4 interface is a very special kind of beast.
705 		 * no multicast, no linklocal.  RFC2529 specifies how to make
706 		 * linklocals for 6to4 interface, but there's no use and
707 		 * it is rather harmful to have one.
708 		 */
709 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
710 		break;
711 	default:
712 		break;
713 	}
714 
715 	/*
716 	 * usually, we require multicast capability to the interface
717 	 */
718 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
719 		nd6log((LOG_INFO, "in6_ifattach: "
720 		    "%s is not multicast capable, IPv6 not enabled\n",
721 		    if_name(ifp)));
722 		return;
723 	}
724 
725 	/*
726 	 * assign loopback address for loopback interface.
727 	 * XXX multiple loopback interface case.
728 	 */
729 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
730 		struct ifaddr *ifa;
731 
732 		in6 = in6addr_loopback;
733 		ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &in6);
734 		if (ifa == NULL) {
735 			if (in6_ifattach_loopback(ifp) != 0)
736 				return;
737 		} else
738 			ifa_free(ifa);
739 	}
740 
741 	/*
742 	 * assign a link-local address, if there's none.
743 	 */
744 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
745 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
746 		int error;
747 
748 		ia = in6ifa_ifpforlinklocal(ifp, 0);
749 		if (ia == NULL) {
750 			error = in6_ifattach_linklocal(ifp, altifp);
751 #if 0
752 			if (error)
753 				log(LOG_NOTICE, "in6_ifattach_linklocal: "
754 				    "failed to add a link-local addr to %s\n",
755 				    if_name(ifp));
756 #endif
757 		} else
758 			ifa_free(&ia->ia_ifa);
759 	}
760 
761 	/* update dynamically. */
762 	if (V_in6_maxmtu < ifp->if_mtu)
763 		V_in6_maxmtu = ifp->if_mtu;
764 }
765 
766 /*
767  * NOTE: in6_ifdetach() does not support loopback if at this moment.
768  * We don't need this function in bsdi, because interfaces are never removed
769  * from the ifnet list in bsdi.
770  */
771 void
772 in6_ifdetach(struct ifnet *ifp)
773 {
774 	struct ifaddr *ifa, *next;
775 
776 	if (ifp->if_afdata[AF_INET6] == NULL)
777 		return;
778 
779 	/* remove neighbor management table */
780 	nd6_purge(ifp);
781 
782 	/*
783 	 * nuke any of IPv6 addresses we have
784 	 * XXX: all addresses should be already removed
785 	 */
786 	TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
787 		if (ifa->ifa_addr->sa_family != AF_INET6)
788 			continue;
789 		in6_purgeaddr(ifa);
790 	}
791 	in6_pcbpurgeif0(&V_udbinfo, ifp);
792 	in6_pcbpurgeif0(&V_ulitecbinfo, ifp);
793 	in6_pcbpurgeif0(&V_ripcbinfo, ifp);
794 	/* leave from all multicast groups joined */
795 	in6_purgemaddrs(ifp);
796 
797 	/*
798 	 * remove neighbor management table.  we call it twice just to make
799 	 * sure we nuke everything.  maybe we need just one call.
800 	 * XXX: since the first call did not release addresses, some prefixes
801 	 * might remain.  We should call nd6_purge() again to release the
802 	 * prefixes after removing all addresses above.
803 	 * (Or can we just delay calling nd6_purge until at this point?)
804 	 */
805 	nd6_purge(ifp);
806 }
807 
808 int
809 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
810     const u_int8_t *baseid, int generate)
811 {
812 	u_int8_t nullbuf[8];
813 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
814 
815 	bzero(nullbuf, sizeof(nullbuf));
816 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
817 		/* we've never created a random ID.  Create a new one. */
818 		generate = 1;
819 	}
820 
821 	if (generate) {
822 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
823 
824 		/* generate_tmp_ifid will update seedn and buf */
825 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
826 		    ndi->randomid);
827 	}
828 	bcopy(ndi->randomid, retbuf, 8);
829 
830 	return (0);
831 }
832 
833 void
834 in6_tmpaddrtimer(void *arg)
835 {
836 	CURVNET_SET((struct vnet *) arg);
837 	struct nd_ifinfo *ndi;
838 	u_int8_t nullbuf[8];
839 	struct ifnet *ifp;
840 
841 	callout_reset(&V_in6_tmpaddrtimer_ch,
842 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
843 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
844 
845 	bzero(nullbuf, sizeof(nullbuf));
846 	TAILQ_FOREACH(ifp, &V_ifnet, if_link) {
847 		if (ifp->if_afdata[AF_INET6] == NULL)
848 			continue;
849 		ndi = ND_IFINFO(ifp);
850 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
851 			/*
852 			 * We've been generating a random ID on this interface.
853 			 * Create a new one.
854 			 */
855 			(void)generate_tmp_ifid(ndi->randomseed0,
856 			    ndi->randomseed1, ndi->randomid);
857 		}
858 	}
859 
860 	CURVNET_RESTORE();
861 }
862 
863 static void
864 in6_purgemaddrs(struct ifnet *ifp)
865 {
866 	LIST_HEAD(,in6_multi)	 purgeinms;
867 	struct in6_multi	*inm, *tinm;
868 	struct ifmultiaddr	*ifma;
869 
870 	LIST_INIT(&purgeinms);
871 	IN6_MULTI_LOCK();
872 
873 	/*
874 	 * Extract list of in6_multi associated with the detaching ifp
875 	 * which the PF_INET6 layer is about to release.
876 	 * We need to do this as IF_ADDR_LOCK() may be re-acquired
877 	 * by code further down.
878 	 */
879 	IF_ADDR_RLOCK(ifp);
880 	TAILQ_FOREACH(ifma, &ifp->if_multiaddrs, ifma_link) {
881 		if (ifma->ifma_addr->sa_family != AF_INET6 ||
882 		    ifma->ifma_protospec == NULL)
883 			continue;
884 		inm = (struct in6_multi *)ifma->ifma_protospec;
885 		LIST_INSERT_HEAD(&purgeinms, inm, in6m_entry);
886 	}
887 	IF_ADDR_RUNLOCK(ifp);
888 
889 	LIST_FOREACH_SAFE(inm, &purgeinms, in6m_entry, tinm) {
890 		LIST_REMOVE(inm, in6m_entry);
891 		in6m_release_locked(inm);
892 	}
893 	mld_ifdetach(ifp);
894 
895 	IN6_MULTI_UNLOCK();
896 }
897