summaryrefslogtreecommitdiff
path: root/sys/netinet6/in6_ifattach.c
blob: cb58178c7318a23dbb2f999e95c5f6bf4872c46f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
/*	$OpenBSD: in6_ifattach.c,v 1.25 2002/05/29 07:54:59 itojun Exp $	*/
/*	$KAME: in6_ifattach.c,v 1.124 2001/07/18 08:32:51 jinmei Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/md5k.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_types.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/if_ether.h>

#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/ip6_var.h>
#include <netinet6/nd6.h>

unsigned long in6_maxmtu = 0;

static int get_rand_ifid(struct ifnet *, struct in6_addr *);
static int get_hw_ifid(struct ifnet *, struct in6_addr *);
static int get_ifid(struct ifnet *, struct ifnet *, struct in6_addr *);
static int in6_ifattach_addaddr(struct ifnet *, struct in6_ifaddr *);
static int in6_ifattach_linklocal(struct ifnet *, struct ifnet *);
static int in6_ifattach_loopback(struct ifnet *);

#define EUI64_GBIT	0x01
#define EUI64_UBIT	0x02
#define EUI64_TO_IFID(in6)	do {(in6)->s6_addr[8] ^= EUI64_UBIT; } while (0)
#define EUI64_GROUP(in6)	((in6)->s6_addr[8] & EUI64_GBIT)
#define EUI64_INDIVIDUAL(in6)	(!EUI64_GROUP(in6))
#define EUI64_LOCAL(in6)	((in6)->s6_addr[8] & EUI64_UBIT)
#define EUI64_UNIVERSAL(in6)	(!EUI64_LOCAL(in6))

#define IFID_LOCAL(in6)		(!EUI64_LOCAL(in6))
#define IFID_UNIVERSAL(in6)	(!EUI64_UNIVERSAL(in6))

/*
 * Generate a last-resort interface identifier, when the machine has no
 * IEEE802/EUI64 address sources.
 * The goal here is to get an interface identifier that is
 * (1) random enough and (2) does not change across reboot.
 * We currently use MD5(hostname) for it.
 */
static int
get_rand_ifid(ifp, in6)
	struct ifnet *ifp;
	struct in6_addr *in6;	/* upper 64bits are preserved */
{
	MD5_CTX ctxt;
	u_int8_t digest[16];

#if 0
	/* we need at least several letters as seed for ifid */
	if (hostnamelen < 3)
		return -1;
#endif

	/* generate 8 bytes of pseudo-random value. */
	bzero(&ctxt, sizeof(ctxt));
	MD5Init(&ctxt);
	MD5Update(&ctxt, hostname, hostnamelen);
	MD5Final(digest, &ctxt);

	/* assumes sizeof(digest) > sizeof(ifid) */
	bcopy(digest, &in6->s6_addr[8], 8);

	/* make sure to set "u" bit to local, and "g" bit to individual. */
	in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
	in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */

	/* convert EUI64 into IPv6 interface identifier */
	EUI64_TO_IFID(in6);

	return 0;
}

/*
 * Get interface identifier for the specified interface.
 * XXX assumes single sockaddr_dl (AF_LINK address) per an interface
 */
static int
get_hw_ifid(ifp, in6)
	struct ifnet *ifp;
	struct in6_addr *in6;	/* upper 64bits are preserved */
{
	struct ifaddr *ifa;
	struct sockaddr_dl *sdl;
	u_int8_t *addr;
	size_t addrlen;
	static u_int8_t allzero[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
	static u_int8_t allone[8] =
		{ 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

	for (ifa = ifp->if_addrlist.tqh_first;
	     ifa;
	     ifa = ifa->ifa_list.tqe_next)
	{
		if (ifa->ifa_addr->sa_family != AF_LINK)
			continue;
		sdl = (struct sockaddr_dl *)ifa->ifa_addr;
		if (sdl == NULL)
			continue;
		if (sdl->sdl_alen == 0)
			continue;

		goto found;
	}

	return -1;

found:
	addr = LLADDR(sdl);
	addrlen = sdl->sdl_alen;

	/* get EUI64 */
	switch (ifp->if_type) {
	case IFT_ETHER:
	case IFT_FDDI:
	case IFT_ATM:
		/* IEEE802/EUI64 cases - what others? */

		/* look at IEEE802/EUI64 only */
		if (addrlen != 8 && addrlen != 6)
			return -1;

		/*
		 * check for invalid MAC address - on bsdi, we see it a lot
		 * since wildboar configures all-zero MAC on pccard before
		 * card insertion.
		 */
		if (bcmp(addr, allzero, addrlen) == 0)
			return -1;
		if (bcmp(addr, allone, addrlen) == 0)
			return -1;

		/* make EUI64 address */
		if (addrlen == 8)
			bcopy(addr, &in6->s6_addr[8], 8);
		else if (addrlen == 6) {
			in6->s6_addr[8] = addr[0];
			in6->s6_addr[9] = addr[1];
			in6->s6_addr[10] = addr[2];
			in6->s6_addr[11] = 0xff;
			in6->s6_addr[12] = 0xfe;
			in6->s6_addr[13] = addr[3];
			in6->s6_addr[14] = addr[4];
			in6->s6_addr[15] = addr[5];
		}
		break;

	case IFT_ARCNET:
		if (addrlen != 1)
			return -1;
		if (!addr[0])
			return -1;

		bzero(&in6->s6_addr[8], 8);
		in6->s6_addr[15] = addr[0];

		/*
		 * due to insufficient bitwidth, we mark it local.
		 */
		in6->s6_addr[8] &= ~EUI64_GBIT;	/* g bit to "individual" */
		in6->s6_addr[8] |= EUI64_UBIT;	/* u bit to "local" */
		break;

	case IFT_GIF:
#ifdef IFT_STF
	case IFT_STF:
#endif
		/*
		 * RFC2893 says: "SHOULD use IPv4 address as ifid source".
		 * however, IPv4 address is not very suitable as unique
		 * identifier source (can be renumbered).
		 * we don't do this.
		 */
		return -1;

	default:
		return -1;
	}

	/* sanity check: g bit must not indicate "group" */
	if (EUI64_GROUP(in6))
		return -1;

	/* convert EUI64 into IPv6 interface identifier */
	EUI64_TO_IFID(in6);

	/*
	 * sanity check: ifid must not be all zero, avoid conflict with
	 * subnet router anycast
	 */
	if ((in6->s6_addr[8] & ~(EUI64_GBIT | EUI64_UBIT)) == 0x00 &&
	    bcmp(&in6->s6_addr[9], allzero, 7) == 0) {
		return -1;
	}

	return 0;
}

/*
 * Get interface identifier for the specified interface.  If it is not
 * available on ifp0, borrow interface identifier from other information
 * sources.
 */
static int
get_ifid(ifp0, altifp, in6)
	struct ifnet *ifp0;
	struct ifnet *altifp;	/* secondary EUI64 source */
	struct in6_addr *in6;
{
	struct ifnet *ifp;

	/* first, try to get it from the interface itself */
	if (get_hw_ifid(ifp0, in6) == 0) {
		nd6log((LOG_DEBUG,
		    "%s: got interface identifier from itself\n",
		    ifp0->if_xname));
		goto success;
	}

	/* try secondary EUI64 source. this basically is for ATM PVC */
	if (altifp && get_hw_ifid(altifp, in6) == 0) {
		nd6log((LOG_DEBUG, "%s: got interface identifier from %s\n",
		    ifp0->if_xname, altifp->if_xname));
		goto success;
	}

	/* next, try to get it from some other hardware interface */
	for (ifp = ifnet.tqh_first; ifp; ifp = ifp->if_list.tqe_next)
	{
		if (ifp == ifp0)
			continue;
		if (get_hw_ifid(ifp, in6) != 0)
			continue;

		/*
		 * to borrow ifid from other interface, ifid needs to be
		 * globally unique
		 */
		if (IFID_UNIVERSAL(in6)) {
			nd6log((LOG_DEBUG,
			    "%s: borrow interface identifier from %s\n",
			    ifp0->if_xname, ifp->if_xname));
			goto success;
		}
	}

	/* last resort: get from random number source */
	if (get_rand_ifid(ifp, in6) == 0) {
		nd6log((LOG_DEBUG,
		    "%s: interface identifier generated by random number\n",
		    ifp0->if_xname));
		goto success;
	}

	printf("%s: failed to get interface identifier\n", ifp0->if_xname);
	return -1;

success:
	nd6log((LOG_INFO, "%s: ifid: "
		"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x\n",
		ifp0->if_xname,
		in6->s6_addr[8], in6->s6_addr[9],
		in6->s6_addr[10], in6->s6_addr[11],
		in6->s6_addr[12], in6->s6_addr[13],
		in6->s6_addr[14], in6->s6_addr[15]));
	return 0;
}

/*
 * configure IPv6 interface address.  XXX code duplicated with in.c
 */
static int
in6_ifattach_addaddr(ifp, ia)
	struct ifnet *ifp;
	struct in6_ifaddr *ia;
{
	struct in6_ifaddr *oia;
	struct ifaddr *ifa;
	int error;
	int rtflag;
	struct in6_addr llsol;

	/*
	 * initialize if_addrlist, if we are the very first one
	 */
	ifa = TAILQ_FIRST(&ifp->if_addrlist);
	if (ifa == NULL) {
		TAILQ_INIT(&ifp->if_addrlist);
	}

	/*
	 * link the interface address to global list
	 */
	TAILQ_INSERT_TAIL(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
	ia->ia_ifa.ifa_refcnt++;

	/*
	 * Also link into the IPv6 address chain beginning with in6_ifaddr.
	 * kazu opposed it, but itojun & jinmei wanted.
	 */
	if ((oia = in6_ifaddr) != NULL) {
		for (; oia->ia_next; oia = oia->ia_next)
			continue;
		oia->ia_next = ia;
	} else
		in6_ifaddr = ia;
	ia->ia_ifa.ifa_refcnt++;

	/*
	 * give the interface a chance to initialize, in case this
	 * is the first address to be added.
	 */
	if (ifp->if_ioctl != NULL) {
		int s;
		s = splimp();
		error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia);
		splx(s);
	} else
		error = 0;
	if (error) {
		switch (error) {
		case EAFNOSUPPORT:
			printf("%s: IPv6 not supported\n", ifp->if_xname);
			break;
		default:
			printf("%s: SIOCSIFADDR error %d\n", ifp->if_xname,
			    error);
			break;
		}

		/* undo changes */
		TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
		IFAFREE(&ia->ia_ifa);
		if (oia)
			oia->ia_next = ia->ia_next;
		else
			in6_ifaddr = ia->ia_next;
		IFAFREE(&ia->ia_ifa);
		return -1;
	}

	/* configure link-layer address resolution */
	rtflag = 0;
	if (IN6_ARE_ADDR_EQUAL(&ia->ia_prefixmask.sin6_addr, &in6mask128))
		rtflag = RTF_HOST;
	else {
		switch (ifp->if_type) {
		case IFT_LOOP:
#ifdef IFT_STF
		case IFT_STF:
#endif
			rtflag = 0;
			break;
		default:
			ia->ia_ifa.ifa_rtrequest = nd6_rtrequest;
			ia->ia_ifa.ifa_flags |= RTF_CLONING;
			rtflag = RTF_CLONING;
			break;
		}
	}

	/* add route to the interface. */
	rtrequest(RTM_ADD,
		  (struct sockaddr *)&ia->ia_addr,
		  (struct sockaddr *)&ia->ia_addr,
		  (struct sockaddr *)&ia->ia_prefixmask,
		  RTF_UP | rtflag,
		  (struct rtentry **)0);
	ia->ia_flags |= IFA_ROUTE;

	if ((rtflag & RTF_CLONING) != 0 &&
	    (ifp->if_flags & IFF_MULTICAST) != 0) {
		/* Restore saved multicast addresses (if any). */
		in6_restoremkludge(ia, ifp);

		/*
		 * join solicited multicast address
		 */
		bzero(&llsol, sizeof(llsol));
		llsol.s6_addr16[0] = htons(0xff02);
		llsol.s6_addr16[1] = htons(ifp->if_index);
		llsol.s6_addr32[1] = 0;
		llsol.s6_addr32[2] = htonl(1);
		llsol.s6_addr32[3] = ia->ia_addr.sin6_addr.s6_addr32[3];
		llsol.s6_addr8[12] = 0xff;
		(void)in6_addmulti(&llsol, ifp, &error);

		/* XXX should we run DAD on other interface types? */
		if (in6if_do_dad(ifp)) {
			/* mark the address TENTATIVE, if needed. */
			ia->ia6_flags |= IN6_IFF_TENTATIVE;
			/* nd6_dad_start() will be called in in6_if_up */
		}
	}

	return 0;
}

static int
in6_ifattach_linklocal(ifp, altifp)
	struct ifnet *ifp;
	struct ifnet *altifp;	/*secondary EUI64 source*/
{
	struct in6_ifaddr *ia;

	/*
	 * configure link-local address
	 */
	ia = (struct in6_ifaddr *)malloc(sizeof(*ia), M_IFADDR, M_WAITOK);
	bzero((caddr_t)ia, sizeof(*ia));
	ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
	if (ifp->if_flags & IFF_POINTOPOINT)
		ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
	else
		ia->ia_ifa.ifa_dstaddr = NULL;
	ia->ia_ifa.ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
	ia->ia_ifp = ifp;

	bzero(&ia->ia_prefixmask, sizeof(ia->ia_prefixmask));
	ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_prefixmask.sin6_family = AF_INET6;
	ia->ia_prefixmask.sin6_addr = in6mask64;

	/* just in case */
	bzero(&ia->ia_dstaddr, sizeof(ia->ia_dstaddr));
	ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_dstaddr.sin6_family = AF_INET6;

	bzero(&ia->ia_addr, sizeof(ia->ia_addr));
	ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_addr.sin6_family = AF_INET6;
	ia->ia_addr.sin6_addr.s6_addr16[0] = htons(0xfe80);
	ia->ia_addr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
	ia->ia_addr.sin6_addr.s6_addr32[1] = 0;
	if (ifp->if_flags & IFF_LOOPBACK) {
		ia->ia_addr.sin6_addr.s6_addr32[2] = 0;
		ia->ia_addr.sin6_addr.s6_addr32[3] = htonl(1);
	} else {
		if (get_ifid(ifp, altifp, &ia->ia_addr.sin6_addr) != 0) {
			nd6log((LOG_ERR,
			    "%s: no ifid available\n", ifp->if_xname));
			free(ia, M_IFADDR);
			return -1;
		}
	}

	ia->ia_ifa.ifa_metric = ifp->if_metric;

	if (in6_ifattach_addaddr(ifp, ia) != 0) {
		/* ia will be freed on failure */
		return -1;
	}

	return 0;
}

static int
in6_ifattach_loopback(ifp)
	struct ifnet *ifp;	/* must be IFT_LOOP */
{
	struct in6_ifaddr *ia;

	/*
	 * configure link-local address
	 */
	ia = (struct in6_ifaddr *)malloc(sizeof(*ia), M_IFADDR, M_WAITOK);
	bzero((caddr_t)ia, sizeof(*ia));
	ia->ia_ifa.ifa_addr = (struct sockaddr *)&ia->ia_addr;
	ia->ia_ifa.ifa_dstaddr = (struct sockaddr *)&ia->ia_dstaddr;
	ia->ia_ifa.ifa_netmask = (struct sockaddr *)&ia->ia_prefixmask;
	ia->ia_ifp = ifp;

	bzero(&ia->ia_prefixmask, sizeof(ia->ia_prefixmask));
	ia->ia_prefixmask.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_prefixmask.sin6_family = AF_INET6;
	ia->ia_prefixmask.sin6_addr = in6mask128;

	/*
	 * Always initialize ia_dstaddr (= broadcast address) to loopback
	 * address, to make getifaddr happier.
	 *
	 * For BSDI, it is mandatory.  The BSDI version of
	 * ifa_ifwithroute() rejects to add a route to the loopback
	 * interface.  Even for other systems, loopback looks somewhat
	 * special.
	 */
	bzero(&ia->ia_dstaddr, sizeof(ia->ia_dstaddr));
	ia->ia_dstaddr.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_dstaddr.sin6_family = AF_INET6;
	ia->ia_dstaddr.sin6_addr = in6addr_loopback;

	bzero(&ia->ia_addr, sizeof(ia->ia_addr));
	ia->ia_addr.sin6_len = sizeof(struct sockaddr_in6);
	ia->ia_addr.sin6_family = AF_INET6;
	ia->ia_addr.sin6_addr = in6addr_loopback;

	ia->ia_ifa.ifa_metric = ifp->if_metric;

	if (in6_ifattach_addaddr(ifp, ia) != 0) {
		/* ia will be freed on failure */
		return -1;
	}

	return 0;
}

/*
 * XXX multiple loopback interface needs more care.  for instance,
 * nodelocal address needs to be configured onto only one of them.
 * XXX multiple link-local address case
 */
void
in6_ifattach(ifp, altifp)
	struct ifnet *ifp;
	struct ifnet *altifp;	/* secondary EUI64 source */
{
	struct sockaddr_in6 mltaddr;
	struct sockaddr_in6 mltmask;
	struct sockaddr_in6 gate;
	struct sockaddr_in6 mask;
	struct in6_ifaddr *ia;
	struct in6_addr in6;

	/* some of the interfaces are inherently not IPv6 capable */
	switch (ifp->if_type) {
	case IFT_BRIDGE:
	case IFT_ENC:
	case IFT_PFLOG:
		return;
	case IFT_PROPVIRTUAL:
		if (strncmp("bridge", ifp->if_xname, sizeof("bridge")) == 0 &&
		    '0' <= ifp->if_xname[sizeof("bridge")] &&
		    ifp->if_xname[sizeof("bridge")] <= '9')
			return;
		break;
	}

	/*
	 * if link mtu is too small, don't try to configure IPv6.
	 * remember there could be some link-layer that has special
	 * fragmentation logic.
	 */
	if (ifp->if_mtu < IPV6_MMTU)
		return;

	/* create a multicast kludge storage (if we have not had one) */
	in6_createmkludge(ifp);

	/*
	 * quirks based on interface type
	 */
	switch (ifp->if_type) {
#ifdef IFT_STF
	case IFT_STF:
		/*
		 * 6to4 interface is a very special kind of beast.
		 * no multicast, no linklocal.  RFC2529 specifies how to make
		 * linklocals for 6to4 interface, but there's no use and
		 * it is rather harmful to have one.
		 */
		return;
#endif
	default:
		break;
	}

	/*
	 * usually, we require multicast capability to the interface
	 */
	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
		log(LOG_INFO, "in6_ifattach: "
		    "%s is not multicast capable, IPv6 not enabled\n",
		    ifp->if_xname);
		return;
	}

	/*
	 * assign link-local address, if there's none 
	 */
	ia = in6ifa_ifpforlinklocal(ifp, 0);
	if (ia == NULL) {
		if (in6_ifattach_linklocal(ifp, altifp) != 0)
			return;
		ia = in6ifa_ifpforlinklocal(ifp, 0);

		if (ia == NULL) {
			printf("%s: failed to add link-local address\n",
			    ifp->if_xname);

			/* we can't initialize multicasts without link-local */
			return;
		}
	}

	if (ifp->if_flags & IFF_POINTOPOINT) {
		/*
		 * route local address to loopback
		 */
		bzero(&gate, sizeof(gate));
		gate.sin6_len = sizeof(struct sockaddr_in6);
		gate.sin6_family = AF_INET6;
		gate.sin6_addr = in6addr_loopback;
		bzero(&mask, sizeof(mask));
		mask.sin6_len = sizeof(struct sockaddr_in6);
		mask.sin6_family = AF_INET6;
		mask.sin6_addr = in6mask64;
		rtrequest(RTM_ADD,
			  (struct sockaddr *)&ia->ia_addr,
			  (struct sockaddr *)&gate,
			  (struct sockaddr *)&mask,
			  RTF_UP|RTF_HOST,
			  (struct rtentry **)0);
	}

	/*
	 * assign loopback address for loopback interface
	 * XXX multiple loopback interface case
	 */
	in6 = in6addr_loopback;
	if (ifp->if_flags & IFF_LOOPBACK) {
		if (in6ifa_ifpwithaddr(ifp, &in6) == NULL) {
			if (in6_ifattach_loopback(ifp) != 0)
				return;
		}
	}

#ifdef DIAGNOSTIC
	if (!ia) {
		panic("ia == NULL in in6_ifattach");
		/*NOTREACHED*/
	}
#endif

	/*
	 * join multicast
	 */
	if (ifp->if_flags & IFF_MULTICAST) {
		int error;	/* not used */
		struct in6_multi *in6m;

		/* Restore saved multicast addresses(if any). */
		in6_restoremkludge(ia, ifp);

		bzero(&mltmask, sizeof(mltmask));
		mltmask.sin6_len = sizeof(struct sockaddr_in6);
		mltmask.sin6_family = AF_INET6;
		mltmask.sin6_addr = in6mask32;

		/*
		 * join link-local all-nodes address
		 */
		bzero(&mltaddr, sizeof(mltaddr));
		mltaddr.sin6_len = sizeof(struct sockaddr_in6);
		mltaddr.sin6_family = AF_INET6;
		mltaddr.sin6_addr = in6addr_linklocal_allnodes;
		mltaddr.sin6_addr.s6_addr16[1] = htons(ifp->if_index);

		IN6_LOOKUP_MULTI(mltaddr.sin6_addr, ifp, in6m);
		if (in6m == NULL) {
			rtrequest(RTM_ADD,
				  (struct sockaddr *)&mltaddr,
				  (struct sockaddr *)&ia->ia_addr,
				  (struct sockaddr *)&mltmask,
				  RTF_UP|RTF_CLONING,  /* xxx */
				  (struct rtentry **)0);
			(void)in6_addmulti(&mltaddr.sin6_addr, ifp, &error);
		}

		if (ifp->if_flags & IFF_LOOPBACK) {
			in6 = in6addr_loopback;
			ia = in6ifa_ifpwithaddr(ifp, &in6);
			/*
			 * join node-local all-nodes address, on loopback
			 */
			mltaddr.sin6_addr = in6addr_nodelocal_allnodes;

			IN6_LOOKUP_MULTI(mltaddr.sin6_addr, ifp, in6m);
			if (in6m == NULL && ia != NULL) {
				rtrequest(RTM_ADD,
					  (struct sockaddr *)&mltaddr,
					  (struct sockaddr *)&ia->ia_addr,
					  (struct sockaddr *)&mltmask,
					  RTF_UP,
					  (struct rtentry **)0);
				(void)in6_addmulti(&mltaddr.sin6_addr, ifp, &error);
			}
		}
	}
}

/*
 * NOTE: in6_ifdetach() does not support loopback if at this moment.
 */
void
in6_ifdetach(ifp)
	struct ifnet *ifp;
{
	struct in6_ifaddr *ia, *oia;
	struct ifaddr *ifa, *next;
	struct rtentry *rt;
	short rtflags;
	struct sockaddr_in6 sin6;
	struct in6_multi *in6m;

	/* nuke prefix list.  this may try to remove some of ifaddrs as well */
	in6_purgeprefix(ifp);

	/* remove neighbor management table */
	nd6_purge(ifp);

	/* nuke any of IPv6 addresses we have */
	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = next)
	{
		next = ifa->ifa_list.tqe_next;
		if (ifa->ifa_addr->sa_family != AF_INET6)
			continue;
		in6_purgeaddr(ifa, ifp);
	}

	/* undo everything done by in6_ifattach(), just in case */
	for (ifa = ifp->if_addrlist.tqh_first; ifa; ifa = next)
	{
		if (ifa->ifa_addr->sa_family != AF_INET6
		 || !IN6_IS_ADDR_LINKLOCAL(&satosin6(&ifa->ifa_addr)->sin6_addr)) {
			continue;
		}

		ia = (struct in6_ifaddr *)ifa;

		/* leave from all multicast groups joined */
		while ((in6m = LIST_FIRST(&ia->ia6_multiaddrs)) != NULL)
			in6_delmulti(in6m);

		/* remove from the routing table */
		if ((ia->ia_flags & IFA_ROUTE)
		 && (rt = rtalloc1((struct sockaddr *)&ia->ia_addr, 0))) {
			rtflags = rt->rt_flags;
			rtfree(rt);
			rtrequest(RTM_DELETE,
				(struct sockaddr *)&ia->ia_addr,
				(struct sockaddr *)&ia->ia_addr,
				(struct sockaddr *)&ia->ia_prefixmask,
				rtflags, (struct rtentry **)0);
		}

		/* remove from the linked list */
		TAILQ_REMOVE(&ifp->if_addrlist, (struct ifaddr *)ia, ifa_list);
		IFAFREE(&ia->ia_ifa);

		/* also remove from the IPv6 address chain(itojun&jinmei) */
		oia = ia;
		if (oia == (ia = in6_ifaddr))
			in6_ifaddr = ia->ia_next;
		else {
			while (ia->ia_next && (ia->ia_next != oia))
				ia = ia->ia_next;
			if (ia->ia_next)
				ia->ia_next = oia->ia_next;
			else {
				nd6log((LOG_ERR, 
				    "%s: didn't unlink in6ifaddr from "
				    "list\n", ifp->if_xname));
			}
		}

		IFAFREE(&oia->ia_ifa);
	}

	/* cleanup multicast address kludge table, if there is any */
	in6_purgemkludge(ifp);

	/*
	 * remove neighbor management table.  we call it twice just to make
	 * sure we nuke everything.  maybe we need just one call.
	 * XXX: since the first call did not release addresses, some prefixes
	 * might remain.  We should call nd6_purge() again to release the
	 * prefixes after removing all addresses above.
	 * (Or can we just delay calling nd6_purge until at this point?)
	 */
	nd6_purge(ifp);

	/* remove route to link-local allnodes multicast (ff02::1) */
	bzero(&sin6, sizeof(sin6));
	sin6.sin6_len = sizeof(struct sockaddr_in6);
	sin6.sin6_family = AF_INET6;
	sin6.sin6_addr = in6addr_linklocal_allnodes;
	sin6.sin6_addr.s6_addr16[1] = htons(ifp->if_index);
	rt = rtalloc1((struct sockaddr *)&sin6, 0);
	if (rt && rt->rt_ifp == ifp) {
		rtrequest(RTM_DELETE, (struct sockaddr *)rt_key(rt),
			rt->rt_gateway, rt_mask(rt), rt->rt_flags, 0);
		rtfree(rt);
	}
}