xref: /freebsd/sys/netinet6/in6_ifattach.c (revision ddc0daea20280c3a06a910b72b14ffe3f624df71)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	$KAME: in6_ifattach.c,v 1.118 2001/05/24 07:44:00 itojun Exp $
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/jail.h>
43 #include <sys/kernel.h>
44 #include <sys/lock.h>
45 #include <sys/proc.h>
46 #include <sys/rmlock.h>
47 #include <sys/syslog.h>
48 #include <sys/md5.h>
49 
50 #include <net/if.h>
51 #include <net/if_var.h>
52 #include <net/if_dl.h>
53 #include <net/if_types.h>
54 #include <net/route.h>
55 #include <net/vnet.h>
56 
57 #include <netinet/in.h>
58 #include <netinet/in_var.h>
59 #include <netinet/if_ether.h>
60 #include <netinet/in_pcb.h>
61 #include <netinet/ip_var.h>
62 #include <netinet/udp.h>
63 #include <netinet/udp_var.h>
64 
65 #include <netinet/ip6.h>
66 #include <netinet6/ip6_var.h>
67 #include <netinet6/in6_var.h>
68 #include <netinet6/in6_pcb.h>
69 #include <netinet6/in6_ifattach.h>
70 #include <netinet6/ip6_var.h>
71 #include <netinet6/nd6.h>
72 #include <netinet6/mld6_var.h>
73 #include <netinet6/scope6_var.h>
74 
75 VNET_DEFINE(unsigned long, in6_maxmtu) = 0;
76 
77 #ifdef IP6_AUTO_LINKLOCAL
78 VNET_DEFINE(int, ip6_auto_linklocal) = IP6_AUTO_LINKLOCAL;
79 #else
80 VNET_DEFINE(int, ip6_auto_linklocal) = 1;	/* enabled by default */
81 #endif
82 
83 VNET_DEFINE(struct callout, in6_tmpaddrtimer_ch);
84 #define	V_in6_tmpaddrtimer_ch		VNET(in6_tmpaddrtimer_ch)
85 
86 VNET_DECLARE(struct inpcbinfo, ripcbinfo);
87 #define	V_ripcbinfo			VNET(ripcbinfo)
88 
89 static int get_rand_ifid(struct ifnet *, struct in6_addr *);
90 static int generate_tmp_ifid(u_int8_t *, const u_int8_t *, u_int8_t *);
91 static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
92 static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
93 static int in6_ifattach_loopback(struct ifnet *);
94 static void in6_purgemaddrs(struct ifnet *);
95 
96 #define EUI64_GBIT	0x01
97 #define EUI64_UBIT	0x02
98 #define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
99 #define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
100 #define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
101 #define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
102 #define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))
103 
104 #define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
105 #define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))
106 
107 /*
108  * Generate a last-resort interface identifier, when the machine has no
109  * IEEE802/EUI64 address sources.
110  * The goal here is to get an interface identifier that is
111  * (1) random enough and (2) does not change across reboot.
112  * We currently use MD5(hostname) for it.
113  *
114  * in6 - upper 64bits are preserved
115  */
116 static int
117 get_rand_ifid(struct ifnet *ifp, struct in6_addr *in6)
118 {
119 	MD5_CTX ctxt;
120 	struct prison *pr;
121 	u_int8_t digest[16];
122 	int hostnamelen;
123 
124 	pr = curthread->td_ucred->cr_prison;
125 	mtx_lock(&pr->pr_mtx);
126 	hostnamelen = strlen(pr->pr_hostname);
127 #if 0
128 	/* we need at least several letters as seed for ifid */
129 	if (hostnamelen < 3) {
130 		mtx_unlock(&pr->pr_mtx);
131 		return -1;
132 	}
133 #endif
134 
135 	/* generate 8 bytes of pseudo-random value. */
136 	bzero(&ctxt, sizeof(ctxt));
137 	MD5Init(&ctxt);
138 	MD5Update(&ctxt, pr->pr_hostname, hostnamelen);
139 	mtx_unlock(&pr->pr_mtx);
140 	MD5Final(digest, &ctxt);
141 
142 	/* assumes sizeof(digest) > sizeof(ifid) */
143 	bcopy(digest, &in6->s6_addr[8], 8);
144 
145 	/* make sure to set "u" bit to local, and "g" bit to individual. */
146 	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
147 	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
148 
149 	/* convert EUI64 into IPv6 interface identifier */
150 	EUI64_TO_IFID(in6);
151 
152 	return 0;
153 }
154 
155 static int
156 generate_tmp_ifid(u_int8_t *seed0, const u_int8_t *seed1, u_int8_t *ret)
157 {
158 	MD5_CTX ctxt;
159 	u_int8_t seed[16], digest[16], nullbuf[8];
160 	u_int32_t val32;
161 
162 	/* If there's no history, start with a random seed. */
163 	bzero(nullbuf, sizeof(nullbuf));
164 	if (bcmp(nullbuf, seed0, sizeof(nullbuf)) == 0) {
165 		int i;
166 
167 		for (i = 0; i < 2; i++) {
168 			val32 = arc4random();
169 			bcopy(&val32, seed + sizeof(val32) * i, sizeof(val32));
170 		}
171 	} else
172 		bcopy(seed0, seed, 8);
173 
174 	/* copy the right-most 64-bits of the given address */
175 	/* XXX assumption on the size of IFID */
176 	bcopy(seed1, &seed[8], 8);
177 
178 	if (0) {		/* for debugging purposes only */
179 		int i;
180 
181 		printf("generate_tmp_ifid: new randomized ID from: ");
182 		for (i = 0; i < 16; i++)
183 			printf("%02x", seed[i]);
184 		printf(" ");
185 	}
186 
187 	/* generate 16 bytes of pseudo-random value. */
188 	bzero(&ctxt, sizeof(ctxt));
189 	MD5Init(&ctxt);
190 	MD5Update(&ctxt, seed, sizeof(seed));
191 	MD5Final(digest, &ctxt);
192 
193 	/*
194 	 * RFC 3041 3.2.1. (3)
195 	 * Take the left-most 64-bits of the MD5 digest and set bit 6 (the
196 	 * left-most bit is numbered 0) to zero.
197 	 */
198 	bcopy(digest, ret, 8);
199 	ret[0] &= ~EUI64_UBIT;
200 
201 	/*
202 	 * XXX: we'd like to ensure that the generated value is not zero
203 	 * for simplicity.  If the caclculated digest happens to be zero,
204 	 * use a random non-zero value as the last resort.
205 	 */
206 	if (bcmp(nullbuf, ret, sizeof(nullbuf)) == 0) {
207 		nd6log((LOG_INFO,
208 		    "generate_tmp_ifid: computed MD5 value is zero.\n"));
209 
210 		val32 = arc4random();
211 		val32 = 1 + (val32 % (0xffffffff - 1));
212 	}
213 
214 	/*
215 	 * RFC 3041 3.2.1. (4)
216 	 * Take the rightmost 64-bits of the MD5 digest and save them in
217 	 * stable storage as the history value to be used in the next
218 	 * iteration of the algorithm.
219 	 */
220 	bcopy(&digest[8], seed0, 8);
221 
222 	if (0) {		/* for debugging purposes only */
223 		int i;
224 
225 		printf("to: ");
226 		for (i = 0; i < 16; i++)
227 			printf("%02x", digest[i]);
228 		printf("\n");
229 	}
230 
231 	return 0;
232 }
233 
234 /*
235  * Get interface identifier for the specified interface.
236  * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
237  *
238  * in6 - upper 64bits are preserved
239  */
240 int
241 in6_get_hw_ifid(struct ifnet *ifp, struct in6_addr *in6)
242 {
243 	struct epoch_tracker et;
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_ENTER(et);
253 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
254 		if (ifa->ifa_addr->sa_family != AF_LINK)
255 			continue;
256 		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
257 		if (sdl == NULL)
258 			continue;
259 		if (sdl->sdl_alen == 0)
260 			continue;
261 
262 		goto found;
263 	}
264 	NET_EPOCH_EXIT(et);
265 
266 	return -1;
267 
268 found:
269 	IF_ADDR_LOCK_ASSERT(ifp);
270 	addr = LLADDR(sdl);
271 	addrlen = sdl->sdl_alen;
272 
273 	/* get EUI64 */
274 	switch (ifp->if_type) {
275 	case IFT_BRIDGE:
276 	case IFT_ETHER:
277 	case IFT_L2VLAN:
278 	case IFT_ATM:
279 	case IFT_IEEE1394:
280 		/* IEEE802/EUI64 cases - what others? */
281 		/* IEEE1394 uses 16byte length address starting with EUI64 */
282 		if (addrlen > 8)
283 			addrlen = 8;
284 
285 		/* look at IEEE802/EUI64 only */
286 		if (addrlen != 8 && addrlen != 6) {
287 			NET_EPOCH_EXIT(et);
288 			return -1;
289 		}
290 
291 		/*
292 		 * check for invalid MAC address - on bsdi, we see it a lot
293 		 * since wildboar configures all-zero MAC on pccard before
294 		 * card insertion.
295 		 */
296 		if (bcmp(addr, allzero, addrlen) == 0) {
297 			NET_EPOCH_EXIT(et);
298 			return -1;
299 		}
300 		if (bcmp(addr, allone, addrlen) == 0) {
301 			NET_EPOCH_EXIT(et);
302 			return -1;
303 		}
304 
305 		/* make EUI64 address */
306 		if (addrlen == 8)
307 			bcopy(addr, &in6->s6_addr[8], 8);
308 		else if (addrlen == 6) {
309 			in6->s6_addr[8] = addr[0];
310 			in6->s6_addr[9] = addr[1];
311 			in6->s6_addr[10] = addr[2];
312 			in6->s6_addr[11] = 0xff;
313 			in6->s6_addr[12] = 0xfe;
314 			in6->s6_addr[13] = addr[3];
315 			in6->s6_addr[14] = addr[4];
316 			in6->s6_addr[15] = addr[5];
317 		}
318 		break;
319 
320 	case IFT_GIF:
321 	case IFT_STF:
322 		/*
323 		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
324 		 * however, IPv4 address is not very suitable as unique
325 		 * identifier source (can be renumbered).
326 		 * we don't do this.
327 		 */
328 		NET_EPOCH_EXIT(et);
329 		return -1;
330 
331 	case IFT_INFINIBAND:
332 		if (addrlen != 20) {
333 			NET_EPOCH_EXIT(et);
334 			return -1;
335 		}
336 		bcopy(addr + 12, &in6->s6_addr[8], 8);
337 		break;
338 
339 	default:
340 		NET_EPOCH_EXIT(et);
341 		return -1;
342 	}
343 
344 	/* sanity check: g bit must not indicate "group" */
345 	if (EUI64_GROUP(in6)) {
346 		NET_EPOCH_EXIT(et);
347 		return -1;
348 	}
349 
350 	/* convert EUI64 into IPv6 interface identifier */
351 	EUI64_TO_IFID(in6);
352 
353 	/*
354 	 * sanity check: ifid must not be all zero, avoid conflict with
355 	 * subnet router anycast
356 	 */
357 	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
358 	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
359 		NET_EPOCH_EXIT(et);
360 		return -1;
361 	}
362 
363 	NET_EPOCH_EXIT(et);
364 	return 0;
365 }
366 
367 /*
368  * Get interface identifier for the specified interface.  If it is not
369  * available on ifp0, borrow interface identifier from other information
370  * sources.
371  *
372  * altifp - secondary EUI64 source
373  */
374 static int
375 get_ifid(struct ifnet *ifp0, struct ifnet *altifp,
376     struct in6_addr *in6)
377 {
378 	struct epoch_tracker et;
379 	struct ifnet *ifp;
380 
381 	/* first, try to get it from the interface itself */
382 	if (in6_get_hw_ifid(ifp0, in6) == 0) {
383 		nd6log((LOG_DEBUG, "%s: got interface identifier from itself\n",
384 		    if_name(ifp0)));
385 		goto success;
386 	}
387 
388 	/* try secondary EUI64 source. this basically is for ATM PVC */
389 	if (altifp && in6_get_hw_ifid(altifp, in6) == 0) {
390 		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
391 		    if_name(ifp0), if_name(altifp)));
392 		goto success;
393 	}
394 
395 	/* next, try to get it from some other hardware interface */
396 	NET_EPOCH_ENTER(et);
397 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
398 		if (ifp == ifp0)
399 			continue;
400 		if (in6_get_hw_ifid(ifp, in6) != 0)
401 			continue;
402 
403 		/*
404 		 * to borrow ifid from other interface, ifid needs to be
405 		 * globally unique
406 		 */
407 		if (IFID_UNIVERSAL(in6)) {
408 			nd6log((LOG_DEBUG,
409 			    "%s: borrow interface identifier from %s\n",
410 			    if_name(ifp0), if_name(ifp)));
411 			NET_EPOCH_EXIT(et);
412 			goto success;
413 		}
414 	}
415 	NET_EPOCH_EXIT(et);
416 
417 	/* last resort: get from random number source */
418 	if (get_rand_ifid(ifp, in6) == 0) {
419 		nd6log((LOG_DEBUG,
420 		    "%s: interface identifier generated by random number\n",
421 		    if_name(ifp0)));
422 		goto success;
423 	}
424 
425 	printf("%s: failed to get interface identifier\n", if_name(ifp0));
426 	return -1;
427 
428 success:
429 	nd6log((LOG_INFO, "%s: ifid: %02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
430 	    if_name(ifp0), in6->s6_addr[8], in6->s6_addr[9], in6->s6_addr[10],
431 	    in6->s6_addr[11], in6->s6_addr[12], in6->s6_addr[13],
432 	    in6->s6_addr[14], in6->s6_addr[15]));
433 	return 0;
434 }
435 
436 /*
437  * altifp - secondary EUI64 source
438  */
439 static int
440 in6_ifattach_linklocal(struct ifnet *ifp, struct ifnet *altifp)
441 {
442 	struct in6_ifaddr *ia;
443 	struct in6_aliasreq ifra;
444 	struct nd_prefixctl pr0;
445 	struct nd_prefix *pr;
446 	int error;
447 
448 	/*
449 	 * configure link-local address.
450 	 */
451 	in6_prepare_ifra(&ifra, NULL, &in6mask64);
452 
453 	ifra.ifra_addr.sin6_addr.s6_addr32[0] = htonl(0xfe800000);
454 	ifra.ifra_addr.sin6_addr.s6_addr32[1] = 0;
455 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
456 		ifra.ifra_addr.sin6_addr.s6_addr32[2] = 0;
457 		ifra.ifra_addr.sin6_addr.s6_addr32[3] = htonl(1);
458 	} else {
459 		if (get_ifid(ifp, altifp, &ifra.ifra_addr.sin6_addr) != 0) {
460 			nd6log((LOG_ERR,
461 			    "%s: no ifid available\n", if_name(ifp)));
462 			return (-1);
463 		}
464 	}
465 	if (in6_setscope(&ifra.ifra_addr.sin6_addr, ifp, NULL))
466 		return (-1);
467 
468 	/* link-local addresses should NEVER expire. */
469 	ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
470 	ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;
471 
472 	/*
473 	 * Now call in6_update_ifa() to do a bunch of procedures to configure
474 	 * a link-local address. We can set the 3rd argument to NULL, because
475 	 * we know there's no other link-local address on the interface
476 	 * and therefore we are adding one (instead of updating one).
477 	 */
478 	if ((error = in6_update_ifa(ifp, &ifra, NULL,
479 				    IN6_IFAUPDATE_DADDELAY)) != 0) {
480 		/*
481 		 * XXX: When the interface does not support IPv6, this call
482 		 * would fail in the SIOCSIFADDR ioctl.  I believe the
483 		 * notification is rather confusing in this case, so just
484 		 * suppress it.  (jinmei@kame.net 20010130)
485 		 */
486 		if (error != EAFNOSUPPORT)
487 			nd6log((LOG_NOTICE, "in6_ifattach_linklocal: failed to "
488 			    "configure a link-local address on %s "
489 			    "(errno=%d)\n",
490 			    if_name(ifp), error));
491 		return (-1);
492 	}
493 
494 	ia = in6ifa_ifpforlinklocal(ifp, 0);
495 	if (ia == NULL) {
496 		/*
497 		 * Another thread removed the address that we just added.
498 		 * This should be rare, but it happens.
499 		 */
500 		nd6log((LOG_NOTICE, "%s: %s: new link-local address "
501 			"disappeared\n", __func__, if_name(ifp)));
502 		return (-1);
503 	}
504 	ifa_free(&ia->ia_ifa);
505 
506 	/*
507 	 * Make the link-local prefix (fe80::%link/64) as on-link.
508 	 * Since we'd like to manage prefixes separately from addresses,
509 	 * we make an ND6 prefix structure for the link-local prefix,
510 	 * and add it to the prefix list as a never-expire prefix.
511 	 * XXX: this change might affect some existing code base...
512 	 */
513 	bzero(&pr0, sizeof(pr0));
514 	pr0.ndpr_ifp = ifp;
515 	/* this should be 64 at this moment. */
516 	pr0.ndpr_plen = in6_mask2len(&ifra.ifra_prefixmask.sin6_addr, NULL);
517 	pr0.ndpr_prefix = ifra.ifra_addr;
518 	/* apply the mask for safety. (nd6_prelist_add will apply it again) */
519 	IN6_MASK_ADDR(&pr0.ndpr_prefix.sin6_addr, &in6mask64);
520 	/*
521 	 * Initialize parameters.  The link-local prefix must always be
522 	 * on-link, and its lifetimes never expire.
523 	 */
524 	pr0.ndpr_raf_onlink = 1;
525 	pr0.ndpr_raf_auto = 1;	/* probably meaningless */
526 	pr0.ndpr_vltime = ND6_INFINITE_LIFETIME;
527 	pr0.ndpr_pltime = ND6_INFINITE_LIFETIME;
528 	/*
529 	 * Since there is no other link-local addresses, nd6_prefix_lookup()
530 	 * probably returns NULL.  However, we cannot always expect the result.
531 	 * For example, if we first remove the (only) existing link-local
532 	 * address, and then reconfigure another one, the prefix is still
533 	 * valid with referring to the old link-local address.
534 	 */
535 	if ((pr = nd6_prefix_lookup(&pr0)) == NULL) {
536 		if ((error = nd6_prelist_add(&pr0, NULL, NULL)) != 0)
537 			return (error);
538 	} else
539 		nd6_prefix_rele(pr);
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 	/*
568 	 * We are sure that this is a newly assigned address, so we can set
569 	 * NULL to the 3rd arg.
570 	 */
571 	if ((error = in6_update_ifa(ifp, &ifra, NULL, 0)) != 0) {
572 		nd6log((LOG_ERR, "in6_ifattach_loopback: failed to configure "
573 		    "the loopback address on %s (errno=%d)\n",
574 		    if_name(ifp), error));
575 		return (-1);
576 	}
577 
578 	return 0;
579 }
580 
581 /*
582  * compute NI group address, based on the current hostname setting.
583  * see RFC 4620.
584  *
585  * when ifp == NULL, the caller is responsible for filling scopeid.
586  *
587  * If oldmcprefix == 1, FF02:0:0:0:0:2::/96 is used for NI group address
588  * while it is FF02:0:0:0:0:2:FF00::/104 in RFC 4620.
589  */
590 static int
591 in6_nigroup0(struct ifnet *ifp, const char *name, int namelen,
592     struct in6_addr *in6, int oldmcprefix)
593 {
594 	struct prison *pr;
595 	const char *p;
596 	u_char *q;
597 	MD5_CTX ctxt;
598 	u_int8_t digest[16];
599 	char l;
600 	char n[64];	/* a single label must not exceed 63 chars */
601 
602 	/*
603 	 * If no name is given and namelen is -1,
604 	 * we try to do the hostname lookup ourselves.
605 	 */
606 	if (!name && namelen == -1) {
607 		pr = curthread->td_ucred->cr_prison;
608 		mtx_lock(&pr->pr_mtx);
609 		name = pr->pr_hostname;
610 		namelen = strlen(name);
611 	} else
612 		pr = NULL;
613 	if (!name || !namelen) {
614 		if (pr != NULL)
615 			mtx_unlock(&pr->pr_mtx);
616 		return -1;
617 	}
618 
619 	p = name;
620 	while (p && *p && *p != '.' && p - name < namelen)
621 		p++;
622 	if (p == name || p - name > sizeof(n) - 1) {
623 		if (pr != NULL)
624 			mtx_unlock(&pr->pr_mtx);
625 		return -1;	/* label too long */
626 	}
627 	l = p - name;
628 	strncpy(n, name, l);
629 	if (pr != NULL)
630 		mtx_unlock(&pr->pr_mtx);
631 	n[(int)l] = '\0';
632 	for (q = n; *q; q++) {
633 		if ('A' <= *q && *q <= 'Z')
634 			*q = *q - 'A' + 'a';
635 	}
636 
637 	/* generate 16 bytes of pseudo-random value. */
638 	bzero(&ctxt, sizeof(ctxt));
639 	MD5Init(&ctxt);
640 	MD5Update(&ctxt, &l, sizeof(l));
641 	MD5Update(&ctxt, n, l);
642 	MD5Final(digest, &ctxt);
643 
644 	bzero(in6, sizeof(*in6));
645 	in6->s6_addr16[0] = IPV6_ADDR_INT16_MLL;
646 	in6->s6_addr8[11] = 2;
647 	if (oldmcprefix == 0) {
648 		in6->s6_addr8[12] = 0xff;
649 	 	/* Copy the first 24 bits of 128-bit hash into the address. */
650 		bcopy(digest, &in6->s6_addr8[13], 3);
651 	} else {
652 	 	/* Copy the first 32 bits of 128-bit hash into the address. */
653 		bcopy(digest, &in6->s6_addr32[3], sizeof(in6->s6_addr32[3]));
654 	}
655 	if (in6_setscope(in6, ifp, NULL))
656 		return (-1); /* XXX: should not fail */
657 
658 	return 0;
659 }
660 
661 int
662 in6_nigroup(struct ifnet *ifp, const char *name, int namelen,
663     struct in6_addr *in6)
664 {
665 
666 	return (in6_nigroup0(ifp, name, namelen, in6, 0));
667 }
668 
669 int
670 in6_nigroup_oldmcprefix(struct ifnet *ifp, const char *name, int namelen,
671     struct in6_addr *in6)
672 {
673 
674 	return (in6_nigroup0(ifp, name, namelen, in6, 1));
675 }
676 
677 /*
678  * XXX multiple loopback interface needs more care.  for instance,
679  * nodelocal address needs to be configured onto only one of them.
680  * XXX multiple link-local address case
681  *
682  * altifp - secondary EUI64 source
683  */
684 void
685 in6_ifattach(struct ifnet *ifp, struct ifnet *altifp)
686 {
687 	struct in6_ifaddr *ia;
688 
689 	if (ifp->if_afdata[AF_INET6] == NULL)
690 		return;
691 	/*
692 	 * quirks based on interface type
693 	 */
694 	switch (ifp->if_type) {
695 	case IFT_STF:
696 		/*
697 		 * 6to4 interface is a very special kind of beast.
698 		 * no multicast, no linklocal.  RFC2529 specifies how to make
699 		 * linklocals for 6to4 interface, but there's no use and
700 		 * it is rather harmful to have one.
701 		 */
702 		ND_IFINFO(ifp)->flags &= ~ND6_IFF_AUTO_LINKLOCAL;
703 		ND_IFINFO(ifp)->flags |= ND6_IFF_NO_DAD;
704 		break;
705 	default:
706 		break;
707 	}
708 
709 	/*
710 	 * usually, we require multicast capability to the interface
711 	 */
712 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
713 		nd6log((LOG_INFO, "in6_ifattach: "
714 		    "%s is not multicast capable, IPv6 not enabled\n",
715 		    if_name(ifp)));
716 		return;
717 	}
718 
719 	/*
720 	 * assign loopback address for loopback interface.
721 	 */
722 	if ((ifp->if_flags & IFF_LOOPBACK) != 0) {
723 		/*
724 		 * check that loopback address doesn't exist yet.
725 		 */
726 		ia = in6ifa_ifwithaddr(&in6addr_loopback, 0);
727 		if (ia == NULL)
728 			in6_ifattach_loopback(ifp);
729 		else
730 			ifa_free(&ia->ia_ifa);
731 	}
732 
733 	/*
734 	 * assign a link-local address, if there's none.
735 	 */
736 	if (!(ND_IFINFO(ifp)->flags & ND6_IFF_IFDISABLED) &&
737 	    ND_IFINFO(ifp)->flags & ND6_IFF_AUTO_LINKLOCAL) {
738 		ia = in6ifa_ifpforlinklocal(ifp, 0);
739 		if (ia == NULL)
740 			in6_ifattach_linklocal(ifp, altifp);
741 		else
742 			ifa_free(&ia->ia_ifa);
743 	}
744 
745 	/* update dynamically. */
746 	if (V_in6_maxmtu < ifp->if_mtu)
747 		V_in6_maxmtu = ifp->if_mtu;
748 }
749 
750 /*
751  * NOTE: in6_ifdetach() does not support loopback if at this moment.
752  *
753  * When shutting down a VNET we clean up layers top-down.  In that case
754  * upper layer protocols (ulp) are cleaned up already and locks are destroyed
755  * and we must not call into these cleanup functions anymore, thus purgeulp
756  * is set to 0 in that case by in6_ifdetach_destroy().
757  * The normal case of destroying a (cloned) interface still needs to cleanup
758  * everything related to the interface and will have purgeulp set to 1.
759  */
760 static void
761 _in6_ifdetach(struct ifnet *ifp, int purgeulp)
762 {
763 	struct ifaddr *ifa, *next;
764 
765 	if (ifp->if_afdata[AF_INET6] == NULL)
766 		return;
767 
768 	/*
769 	 * nuke any of IPv6 addresses we have
770 	 */
771 	CK_STAILQ_FOREACH_SAFE(ifa, &ifp->if_addrhead, ifa_link, next) {
772 		if (ifa->ifa_addr->sa_family != AF_INET6)
773 			continue;
774 		in6_purgeaddr(ifa);
775 	}
776 	if (purgeulp) {
777 		IN6_MULTI_LOCK();
778 		in6_pcbpurgeif0(&V_udbinfo, ifp);
779 		in6_pcbpurgeif0(&V_ulitecbinfo, ifp);
780 		in6_pcbpurgeif0(&V_ripcbinfo, ifp);
781 		IN6_MULTI_UNLOCK();
782 	}
783 	/* leave from all multicast groups joined */
784 	in6_purgemaddrs(ifp);
785 
786 	/*
787 	 * Remove neighbor management table.
788 	 * Enabling the nd6_purge will panic on vmove for interfaces on VNET
789 	 * teardown as the IPv6 layer is cleaned up already and the locks
790 	 * are destroyed.
791 	 */
792 	if (purgeulp)
793 		nd6_purge(ifp);
794 }
795 
796 void
797 in6_ifdetach(struct ifnet *ifp)
798 {
799 
800 	_in6_ifdetach(ifp, 1);
801 }
802 
803 void
804 in6_ifdetach_destroy(struct ifnet *ifp)
805 {
806 
807 	_in6_ifdetach(ifp, 0);
808 }
809 
810 int
811 in6_get_tmpifid(struct ifnet *ifp, u_int8_t *retbuf,
812     const u_int8_t *baseid, int generate)
813 {
814 	u_int8_t nullbuf[8];
815 	struct nd_ifinfo *ndi = ND_IFINFO(ifp);
816 
817 	bzero(nullbuf, sizeof(nullbuf));
818 	if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) == 0) {
819 		/* we've never created a random ID.  Create a new one. */
820 		generate = 1;
821 	}
822 
823 	if (generate) {
824 		bcopy(baseid, ndi->randomseed1, sizeof(ndi->randomseed1));
825 
826 		/* generate_tmp_ifid will update seedn and buf */
827 		(void)generate_tmp_ifid(ndi->randomseed0, ndi->randomseed1,
828 		    ndi->randomid);
829 	}
830 	bcopy(ndi->randomid, retbuf, 8);
831 
832 	return (0);
833 }
834 
835 void
836 in6_tmpaddrtimer(void *arg)
837 {
838 	CURVNET_SET((struct vnet *) arg);
839 	struct nd_ifinfo *ndi;
840 	u_int8_t nullbuf[8];
841 	struct ifnet *ifp;
842 
843 	callout_reset(&V_in6_tmpaddrtimer_ch,
844 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
845 	    V_ip6_temp_regen_advance) * hz, in6_tmpaddrtimer, curvnet);
846 
847 	bzero(nullbuf, sizeof(nullbuf));
848 	CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link) {
849 		if (ifp->if_afdata[AF_INET6] == NULL)
850 			continue;
851 		ndi = ND_IFINFO(ifp);
852 		if (bcmp(ndi->randomid, nullbuf, sizeof(nullbuf)) != 0) {
853 			/*
854 			 * We've been generating a random ID on this interface.
855 			 * Create a new one.
856 			 */
857 			(void)generate_tmp_ifid(ndi->randomseed0,
858 			    ndi->randomseed1, ndi->randomid);
859 		}
860 	}
861 
862 	CURVNET_RESTORE();
863 }
864 
865 static void
866 in6_purgemaddrs(struct ifnet *ifp)
867 {
868 	struct in6_multi_head inmh;
869 
870 	SLIST_INIT(&inmh);
871 	IN6_MULTI_LOCK();
872 	IN6_MULTI_LIST_LOCK();
873 	mld_ifdetach(ifp, &inmh);
874 	IN6_MULTI_LIST_UNLOCK();
875 	IN6_MULTI_UNLOCK();
876 	in6m_release_list_deferred(&inmh);
877 
878 	/*
879 	 * Make sure all multicast deletions invoking if_ioctl() are
880 	 * completed before returning. Else we risk accessing a freed
881 	 * ifnet structure pointer.
882 	 */
883 	in6m_release_wait();
884 }
885 
886 void
887 in6_ifattach_destroy(void)
888 {
889 
890 	callout_drain(&V_in6_tmpaddrtimer_ch);
891 }
892 
893 static void
894 in6_ifattach_init(void *dummy)
895 {
896 
897 	/* Timer for regeneranation of temporary addresses randomize ID. */
898 	callout_init(&V_in6_tmpaddrtimer_ch, 0);
899 	callout_reset(&V_in6_tmpaddrtimer_ch,
900 	    (V_ip6_temp_preferred_lifetime - V_ip6_desync_factor -
901 	    V_ip6_temp_regen_advance) * hz,
902 	    in6_tmpaddrtimer, curvnet);
903 }
904 
905 /*
906  * Cheat.
907  * This must be after route_init(), which is now SI_ORDER_THIRD.
908  */
909 SYSINIT(in6_ifattach_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_MIDDLE,
910     in6_ifattach_init, NULL);
911