xref: /freebsd/sys/netinet/ip_carp.c (revision 2e1417489338b971e5fd599ff48b5f65df9e8d3b)
1 /*
2  * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
3  * Copyright (c) 2003 Ryan McBride. 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  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
18  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
20  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
24  * THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
29 
30 #include "opt_bpf.h"
31 #include "opt_inet.h"
32 #include "opt_inet6.h"
33 
34 #include <sys/types.h>
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/conf.h>
38 #include <sys/kernel.h>
39 #include <sys/limits.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/module.h>
43 #include <sys/time.h>
44 #include <sys/priv.h>
45 #include <sys/proc.h>
46 #include <sys/protosw.h>
47 #include <sys/sysctl.h>
48 #include <sys/syslog.h>
49 #include <sys/signalvar.h>
50 #include <sys/filio.h>
51 #include <sys/sockio.h>
52 
53 #include <sys/socket.h>
54 #include <sys/vnode.h>
55 
56 #include <machine/stdarg.h>
57 
58 #include <net/bpf.h>
59 #include <net/ethernet.h>
60 #include <net/fddi.h>
61 #include <net/iso88025.h>
62 #include <net/if.h>
63 #include <net/if_clone.h>
64 #include <net/if_dl.h>
65 #include <net/if_types.h>
66 #include <net/route.h>
67 #include <net/vnet.h>
68 
69 #if defined(INET) || defined(INET6)
70 #include <netinet/in.h>
71 #include <netinet/in_var.h>
72 #include <netinet/ip_carp.h>
73 #include <netinet/ip.h>
74 
75 #include <machine/in_cksum.h>
76 #endif
77 
78 #ifdef INET
79 #include <netinet/in_systm.h>
80 #include <netinet/ip_var.h>
81 #include <netinet/if_ether.h>
82 #endif
83 
84 #ifdef INET6
85 #include <netinet/icmp6.h>
86 #include <netinet/ip6.h>
87 #include <netinet6/ip6protosw.h>
88 #include <netinet6/ip6_var.h>
89 #include <netinet6/scope6_var.h>
90 #include <netinet6/in6_var.h>
91 #include <netinet6/nd6.h>
92 #endif
93 
94 #include <crypto/sha1.h>
95 
96 #define	CARP_IFNAME	"carp"
97 static MALLOC_DEFINE(M_CARP, "CARP", "CARP interfaces");
98 SYSCTL_DECL(_net_inet_carp);
99 
100 struct carp_softc {
101 	struct ifnet	 	*sc_ifp;	/* Interface clue */
102 	struct ifnet		*sc_carpdev;	/* Pointer to parent interface */
103 	struct in_ifaddr 	*sc_ia;		/* primary iface address */
104 #ifdef INET
105 	struct ip_moptions 	 sc_imo;
106 #endif
107 #ifdef INET6
108 	struct in6_ifaddr 	*sc_ia6;	/* primary iface address v6 */
109 	struct ip6_moptions 	 sc_im6o;
110 #endif /* INET6 */
111 	TAILQ_ENTRY(carp_softc)	 sc_list;
112 
113 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
114 
115 	int			 sc_flags_backup;
116 	int			 sc_suppress;
117 
118 	int			 sc_sendad_errors;
119 #define	CARP_SENDAD_MAX_ERRORS	3
120 	int			 sc_sendad_success;
121 #define	CARP_SENDAD_MIN_SUCCESS 3
122 
123 	int			 sc_vhid;
124 	int			 sc_advskew;
125 	int			 sc_naddrs;
126 	int			 sc_naddrs6;
127 	int			 sc_advbase;	/* seconds */
128 	int			 sc_init_counter;
129 	u_int64_t		 sc_counter;
130 
131 	/* authentication */
132 #define CARP_HMAC_PAD	64
133 	unsigned char sc_key[CARP_KEY_LEN];
134 	unsigned char sc_pad[CARP_HMAC_PAD];
135 	SHA1_CTX sc_sha1;
136 
137 	struct callout		 sc_ad_tmo;	/* advertisement timeout */
138 	struct callout		 sc_md_tmo;	/* master down timeout */
139 	struct callout 		 sc_md6_tmo;	/* master down timeout */
140 
141 	LIST_ENTRY(carp_softc)	 sc_next;	/* Interface clue */
142 };
143 #define	SC2IFP(sc)	((sc)->sc_ifp)
144 
145 int carp_suppress_preempt = 0;
146 int carp_opts[CARPCTL_MAXID] = { 0, 1, 0, 1, 0, 0 };	/* XXX for now */
147 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
148 SYSCTL_INT(_net_inet_carp, CARPCTL_ALLOW, allow, CTLFLAG_RW,
149     &carp_opts[CARPCTL_ALLOW], 0, "Accept incoming CARP packets");
150 SYSCTL_INT(_net_inet_carp, CARPCTL_PREEMPT, preempt, CTLFLAG_RW,
151     &carp_opts[CARPCTL_PREEMPT], 0, "high-priority backup preemption mode");
152 SYSCTL_INT(_net_inet_carp, CARPCTL_LOG, log, CTLFLAG_RW,
153     &carp_opts[CARPCTL_LOG], 0, "log bad carp packets");
154 SYSCTL_INT(_net_inet_carp, CARPCTL_ARPBALANCE, arpbalance, CTLFLAG_RW,
155     &carp_opts[CARPCTL_ARPBALANCE], 0, "balance arp responses");
156 SYSCTL_INT(_net_inet_carp, OID_AUTO, suppress_preempt, CTLFLAG_RD,
157     &carp_suppress_preempt, 0, "Preemption is suppressed");
158 
159 struct carpstats carpstats;
160 SYSCTL_STRUCT(_net_inet_carp, CARPCTL_STATS, stats, CTLFLAG_RW,
161     &carpstats, carpstats,
162     "CARP statistics (struct carpstats, netinet/ip_carp.h)");
163 
164 struct carp_if {
165 	TAILQ_HEAD(, carp_softc) vhif_vrs;
166 	int vhif_nvrs;
167 
168 	struct ifnet 	*vhif_ifp;
169 	struct mtx	 vhif_mtx;
170 };
171 
172 #define	CARP_INET	0
173 #define	CARP_INET6	1
174 static int proto_reg[] = {-1, -1};
175 
176 /* Get carp_if from softc. Valid after carp_set_addr{,6}. */
177 #define	SC2CIF(sc)		((struct carp_if *)(sc)->sc_carpdev->if_carp)
178 
179 /* lock per carp_if queue */
180 #define	CARP_LOCK_INIT(cif)	mtx_init(&(cif)->vhif_mtx, "carp_if", 	\
181 	NULL, MTX_DEF)
182 #define	CARP_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->vhif_mtx)
183 #define	CARP_LOCK_ASSERT(cif)	mtx_assert(&(cif)->vhif_mtx, MA_OWNED)
184 #define	CARP_LOCK(cif)		mtx_lock(&(cif)->vhif_mtx)
185 #define	CARP_UNLOCK(cif)	mtx_unlock(&(cif)->vhif_mtx)
186 
187 #define	CARP_SCLOCK(sc)		mtx_lock(&SC2CIF(sc)->vhif_mtx)
188 #define	CARP_SCUNLOCK(sc)	mtx_unlock(&SC2CIF(sc)->vhif_mtx)
189 #define	CARP_SCLOCK_ASSERT(sc)	mtx_assert(&SC2CIF(sc)->vhif_mtx, MA_OWNED)
190 
191 #define	CARP_LOG(...)	do {				\
192 	if (carp_opts[CARPCTL_LOG] > 0)			\
193 		log(LOG_INFO, __VA_ARGS__);		\
194 } while (0)
195 
196 #define	CARP_DEBUG(...)	do {				\
197 	if (carp_opts[CARPCTL_LOG] > 1)			\
198 		log(LOG_DEBUG, __VA_ARGS__);		\
199 } while (0)
200 
201 static void	carp_hmac_prepare(struct carp_softc *);
202 static void	carp_hmac_generate(struct carp_softc *, u_int32_t *,
203 		    unsigned char *);
204 static int	carp_hmac_verify(struct carp_softc *, u_int32_t *,
205 		    unsigned char *);
206 static void	carp_setroute(struct carp_softc *, int);
207 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
208 static int 	carp_clone_create(struct if_clone *, int, caddr_t);
209 static void 	carp_clone_destroy(struct ifnet *);
210 static void	carpdetach(struct carp_softc *, int);
211 static int	carp_prepare_ad(struct mbuf *, struct carp_softc *,
212 		    struct carp_header *);
213 static void	carp_send_ad_all(void);
214 static void	carp_send_ad(void *);
215 static void	carp_send_ad_locked(struct carp_softc *);
216 #ifdef INET
217 static void	carp_send_arp(struct carp_softc *);
218 #endif
219 static void	carp_master_down(void *);
220 static void	carp_master_down_locked(struct carp_softc *);
221 static int	carp_ioctl(struct ifnet *, u_long, caddr_t);
222 static int	carp_looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
223     		    struct route *);
224 static void	carp_start(struct ifnet *);
225 static void	carp_setrun(struct carp_softc *, sa_family_t);
226 static void	carp_set_state(struct carp_softc *, int);
227 #ifdef INET
228 static int	carp_addrcount(struct carp_if *, struct in_ifaddr *, int);
229 #endif
230 enum	{ CARP_COUNT_MASTER, CARP_COUNT_RUNNING };
231 
232 #ifdef INET
233 static void	carp_multicast_cleanup(struct carp_softc *, int dofree);
234 static int	carp_set_addr(struct carp_softc *, struct sockaddr_in *);
235 static int	carp_del_addr(struct carp_softc *, struct sockaddr_in *);
236 #endif
237 static void	carp_carpdev_state_locked(struct carp_if *);
238 static void	carp_sc_state_locked(struct carp_softc *);
239 #ifdef INET6
240 static void	carp_send_na(struct carp_softc *);
241 static int	carp_set_addr6(struct carp_softc *, struct sockaddr_in6 *);
242 static int	carp_del_addr6(struct carp_softc *, struct sockaddr_in6 *);
243 static void	carp_multicast6_cleanup(struct carp_softc *, int dofree);
244 #endif
245 
246 static LIST_HEAD(, carp_softc) carpif_list;
247 static struct mtx carp_mtx;
248 IFC_SIMPLE_DECLARE(carp, 0);
249 
250 static eventhandler_tag if_detach_event_tag;
251 
252 static __inline u_int16_t
253 carp_cksum(struct mbuf *m, int len)
254 {
255 	return (in_cksum(m, len));
256 }
257 
258 static void
259 carp_hmac_prepare(struct carp_softc *sc)
260 {
261 	u_int8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
262 	u_int8_t vhid = sc->sc_vhid & 0xff;
263 	struct ifaddr *ifa;
264 	int i, found;
265 #ifdef INET
266 	struct in_addr last, cur, in;
267 #endif
268 #ifdef INET6
269 	struct in6_addr last6, cur6, in6;
270 #endif
271 
272 	if (sc->sc_carpdev)
273 		CARP_SCLOCK(sc);
274 
275 	/* XXX: possible race here */
276 
277 	/* compute ipad from key */
278 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
279 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
280 	for (i = 0; i < sizeof(sc->sc_pad); i++)
281 		sc->sc_pad[i] ^= 0x36;
282 
283 	/* precompute first part of inner hash */
284 	SHA1Init(&sc->sc_sha1);
285 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
286 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
287 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
288 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
289 #ifdef INET
290 	cur.s_addr = 0;
291 	do {
292 		found = 0;
293 		last = cur;
294 		cur.s_addr = 0xffffffff;
295 		IF_ADDR_LOCK(SC2IFP(sc));
296 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
297 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
298 			if (ifa->ifa_addr->sa_family == AF_INET &&
299 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
300 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
301 				cur.s_addr = in.s_addr;
302 				found++;
303 			}
304 		}
305 		IF_ADDR_UNLOCK(SC2IFP(sc));
306 		if (found)
307 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
308 	} while (found);
309 #endif /* INET */
310 #ifdef INET6
311 	memset(&cur6, 0, sizeof(cur6));
312 	do {
313 		found = 0;
314 		last6 = cur6;
315 		memset(&cur6, 0xff, sizeof(cur6));
316 		IF_ADDR_LOCK(SC2IFP(sc));
317 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
318 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
319 			if (IN6_IS_SCOPE_EMBED(&in6))
320 				in6.s6_addr16[1] = 0;
321 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
322 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
323 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
324 				cur6 = in6;
325 				found++;
326 			}
327 		}
328 		IF_ADDR_UNLOCK(SC2IFP(sc));
329 		if (found)
330 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
331 	} while (found);
332 #endif /* INET6 */
333 
334 	/* convert ipad to opad */
335 	for (i = 0; i < sizeof(sc->sc_pad); i++)
336 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
337 
338 	if (sc->sc_carpdev)
339 		CARP_SCUNLOCK(sc);
340 }
341 
342 static void
343 carp_hmac_generate(struct carp_softc *sc, u_int32_t counter[2],
344     unsigned char md[20])
345 {
346 	SHA1_CTX sha1ctx;
347 
348 	/* fetch first half of inner hash */
349 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
350 
351 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
352 	SHA1Final(md, &sha1ctx);
353 
354 	/* outer hash */
355 	SHA1Init(&sha1ctx);
356 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
357 	SHA1Update(&sha1ctx, md, 20);
358 	SHA1Final(md, &sha1ctx);
359 }
360 
361 static int
362 carp_hmac_verify(struct carp_softc *sc, u_int32_t counter[2],
363     unsigned char md[20])
364 {
365 	unsigned char md2[20];
366 
367 	CARP_SCLOCK_ASSERT(sc);
368 
369 	carp_hmac_generate(sc, counter, md2);
370 
371 	return (bcmp(md, md2, sizeof(md2)));
372 }
373 
374 static void
375 carp_setroute(struct carp_softc *sc, int cmd)
376 {
377 	struct ifaddr *ifa;
378 	int s;
379 
380 	if (sc->sc_carpdev)
381 		CARP_SCLOCK_ASSERT(sc);
382 
383 	s = splnet();
384 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
385 #ifdef INET
386 		if (ifa->ifa_addr->sa_family == AF_INET &&
387 		    sc->sc_carpdev != NULL) {
388 			int count = carp_addrcount(
389 			    (struct carp_if *)sc->sc_carpdev->if_carp,
390 			    ifatoia(ifa), CARP_COUNT_MASTER);
391 
392 			if ((cmd == RTM_ADD && count == 1) ||
393 			    (cmd == RTM_DELETE && count == 0))
394 				rtinit(ifa, cmd, RTF_UP | RTF_HOST);
395 		}
396 #endif
397 	}
398 	splx(s);
399 }
400 
401 static int
402 carp_clone_create(struct if_clone *ifc, int unit, caddr_t params)
403 {
404 
405 	struct carp_softc *sc;
406 	struct ifnet *ifp;
407 
408 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
409 	ifp = SC2IFP(sc) = if_alloc(IFT_ETHER);
410 	if (ifp == NULL) {
411 		free(sc, M_CARP);
412 		return (ENOSPC);
413 	}
414 
415 	sc->sc_flags_backup = 0;
416 	sc->sc_suppress = 0;
417 	sc->sc_advbase = CARP_DFLTINTV;
418 	sc->sc_vhid = -1;	/* required setting */
419 	sc->sc_advskew = 0;
420 	sc->sc_init_counter = 1;
421 	sc->sc_naddrs = sc->sc_naddrs6 = 0; /* M_ZERO? */
422 #ifdef INET
423 	sc->sc_imo.imo_membership = (struct in_multi **)malloc(
424 	    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
425 	    M_WAITOK);
426 	sc->sc_imo.imo_mfilters = NULL;
427 	sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
428 	sc->sc_imo.imo_multicast_vif = -1;
429 #endif
430 #ifdef INET6
431 	sc->sc_im6o.im6o_membership = (struct in6_multi **)malloc(
432 	    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
433 	    M_WAITOK);
434 	sc->sc_im6o.im6o_mfilters = NULL;
435 	sc->sc_im6o.im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
436 	sc->sc_im6o.im6o_multicast_hlim = CARP_DFLTTL;
437 #endif
438 
439 	callout_init(&sc->sc_ad_tmo, CALLOUT_MPSAFE);
440 	callout_init(&sc->sc_md_tmo, CALLOUT_MPSAFE);
441 	callout_init(&sc->sc_md6_tmo, CALLOUT_MPSAFE);
442 
443 	ifp->if_softc = sc;
444 	if_initname(ifp, CARP_IFNAME, unit);
445 	ifp->if_mtu = ETHERMTU;
446 	ifp->if_flags = IFF_LOOPBACK;
447 	ifp->if_ioctl = carp_ioctl;
448 	ifp->if_output = carp_looutput;
449 	ifp->if_start = carp_start;
450 	ifp->if_type = IFT_CARP;
451 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
452 	ifp->if_hdrlen = 0;
453 	if_attach(ifp);
454 	bpfattach(SC2IFP(sc), DLT_NULL, sizeof(u_int32_t));
455 	mtx_lock(&carp_mtx);
456 	LIST_INSERT_HEAD(&carpif_list, sc, sc_next);
457 	mtx_unlock(&carp_mtx);
458 	return (0);
459 }
460 
461 static void
462 carp_clone_destroy(struct ifnet *ifp)
463 {
464 	struct carp_softc *sc = ifp->if_softc;
465 
466 	if (sc->sc_carpdev)
467 		CARP_SCLOCK(sc);
468 	carpdetach(sc, 1);	/* Returns unlocked. */
469 
470 	mtx_lock(&carp_mtx);
471 	LIST_REMOVE(sc, sc_next);
472 	mtx_unlock(&carp_mtx);
473 	bpfdetach(ifp);
474 	if_detach(ifp);
475 	if_free(ifp);
476 #ifdef INET
477 	free(sc->sc_imo.imo_membership, M_CARP);
478 #endif
479 #ifdef INET6
480 	free(sc->sc_im6o.im6o_membership, M_CARP);
481 #endif
482 	free(sc, M_CARP);
483 }
484 
485 /*
486  * This function can be called on CARP interface destroy path,
487  * and in case of the removal of the underlying interface as
488  * well. We differentiate these two cases: in case of destruction
489  * of the underlying interface, we do not cleanup our multicast
490  * memberships, since they are already freed. But we purge pointers
491  * to multicast structures, since they are no longer valid, to
492  * avoid panic in future calls to carpdetach(). Also, we do not
493  * release the lock on return, because the function will be
494  * called once more, for another CARP instance on the same
495  * interface.
496  */
497 static void
498 carpdetach(struct carp_softc *sc, int unlock)
499 {
500 	struct carp_if *cif;
501 
502 	callout_stop(&sc->sc_ad_tmo);
503 	callout_stop(&sc->sc_md_tmo);
504 	callout_stop(&sc->sc_md6_tmo);
505 
506 	if (sc->sc_suppress)
507 		carp_suppress_preempt--;
508 	sc->sc_suppress = 0;
509 
510 	if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS)
511 		carp_suppress_preempt--;
512 	sc->sc_sendad_errors = 0;
513 
514 	carp_set_state(sc, INIT);
515 	SC2IFP(sc)->if_flags &= ~IFF_UP;
516 	carp_setrun(sc, 0);
517 #ifdef INET
518 	carp_multicast_cleanup(sc, unlock);
519 #endif
520 #ifdef INET6
521 	carp_multicast6_cleanup(sc, unlock);
522 #endif
523 
524 	if (sc->sc_carpdev != NULL) {
525 		cif = (struct carp_if *)sc->sc_carpdev->if_carp;
526 		CARP_LOCK_ASSERT(cif);
527 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
528 		if (!--cif->vhif_nvrs) {
529 			ifpromisc(sc->sc_carpdev, 0);
530 			sc->sc_carpdev->if_carp = NULL;
531 			CARP_LOCK_DESTROY(cif);
532 			free(cif, M_CARP);
533 		} else if (unlock)
534 			CARP_UNLOCK(cif);
535 		sc->sc_carpdev = NULL;
536 	}
537 }
538 
539 /* Detach an interface from the carp. */
540 static void
541 carp_ifdetach(void *arg __unused, struct ifnet *ifp)
542 {
543 	struct carp_if *cif = (struct carp_if *)ifp->if_carp;
544 	struct carp_softc *sc, *nextsc;
545 
546 	if (cif == NULL)
547 		return;
548 
549 	/*
550 	 * XXX: At the end of for() cycle the lock will be destroyed.
551 	 */
552 	CARP_LOCK(cif);
553 	for (sc = TAILQ_FIRST(&cif->vhif_vrs); sc; sc = nextsc) {
554 		nextsc = TAILQ_NEXT(sc, sc_list);
555 		carpdetach(sc, 0);
556 	}
557 }
558 
559 /*
560  * process input packet.
561  * we have rearranged checks order compared to the rfc,
562  * but it seems more efficient this way or not possible otherwise.
563  */
564 #ifdef INET
565 void
566 carp_input(struct mbuf *m, int hlen)
567 {
568 	struct ip *ip = mtod(m, struct ip *);
569 	struct carp_header *ch;
570 	int iplen, len;
571 
572 	CARPSTATS_INC(carps_ipackets);
573 
574 	if (!carp_opts[CARPCTL_ALLOW]) {
575 		m_freem(m);
576 		return;
577 	}
578 
579 	/* check if received on a valid carp interface */
580 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
581 		CARPSTATS_INC(carps_badif);
582 		CARP_DEBUG("carp_input: packet received on non-carp "
583 		    "interface: %s\n",
584 		    m->m_pkthdr.rcvif->if_xname);
585 		m_freem(m);
586 		return;
587 	}
588 
589 	/* verify that the IP TTL is 255.  */
590 	if (ip->ip_ttl != CARP_DFLTTL) {
591 		CARPSTATS_INC(carps_badttl);
592 		CARP_DEBUG("carp_input: received ttl %d != 255 on %s\n",
593 		    ip->ip_ttl,
594 		    m->m_pkthdr.rcvif->if_xname);
595 		m_freem(m);
596 		return;
597 	}
598 
599 	iplen = ip->ip_hl << 2;
600 
601 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
602 		CARPSTATS_INC(carps_badlen);
603 		CARP_DEBUG("carp_input: received len %zd < "
604 		    "sizeof(struct carp_header) on %s\n",
605 		    m->m_len - sizeof(struct ip),
606 		    m->m_pkthdr.rcvif->if_xname);
607 		m_freem(m);
608 		return;
609 	}
610 
611 	if (iplen + sizeof(*ch) < m->m_len) {
612 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
613 			CARPSTATS_INC(carps_hdrops);
614 			CARP_DEBUG("carp_input: pullup failed\n");
615 			return;
616 		}
617 		ip = mtod(m, struct ip *);
618 	}
619 	ch = (struct carp_header *)((char *)ip + iplen);
620 
621 	/*
622 	 * verify that the received packet length is
623 	 * equal to the CARP header
624 	 */
625 	len = iplen + sizeof(*ch);
626 	if (len > m->m_pkthdr.len) {
627 		CARPSTATS_INC(carps_badlen);
628 		CARP_DEBUG("carp_input: packet too short %d on %s\n",
629 		    m->m_pkthdr.len,
630 		    m->m_pkthdr.rcvif->if_xname);
631 		m_freem(m);
632 		return;
633 	}
634 
635 	if ((m = m_pullup(m, len)) == NULL) {
636 		CARPSTATS_INC(carps_hdrops);
637 		return;
638 	}
639 	ip = mtod(m, struct ip *);
640 	ch = (struct carp_header *)((char *)ip + iplen);
641 
642 	/* verify the CARP checksum */
643 	m->m_data += iplen;
644 	if (carp_cksum(m, len - iplen)) {
645 		CARPSTATS_INC(carps_badsum);
646 		CARP_DEBUG("carp_input: checksum failed on %s\n",
647 		    m->m_pkthdr.rcvif->if_xname);
648 		m_freem(m);
649 		return;
650 	}
651 	m->m_data -= iplen;
652 
653 	carp_input_c(m, ch, AF_INET);
654 }
655 #endif
656 
657 #ifdef INET6
658 int
659 carp6_input(struct mbuf **mp, int *offp, int proto)
660 {
661 	struct mbuf *m = *mp;
662 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
663 	struct carp_header *ch;
664 	u_int len;
665 
666 	CARPSTATS_INC(carps_ipackets6);
667 
668 	if (!carp_opts[CARPCTL_ALLOW]) {
669 		m_freem(m);
670 		return (IPPROTO_DONE);
671 	}
672 
673 	/* check if received on a valid carp interface */
674 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
675 		CARPSTATS_INC(carps_badif);
676 		CARP_DEBUG("carp6_input: packet received on non-carp "
677 		    "interface: %s\n",
678 		    m->m_pkthdr.rcvif->if_xname);
679 		m_freem(m);
680 		return (IPPROTO_DONE);
681 	}
682 
683 	/* verify that the IP TTL is 255 */
684 	if (ip6->ip6_hlim != CARP_DFLTTL) {
685 		CARPSTATS_INC(carps_badttl);
686 		CARP_DEBUG("carp6_input: received ttl %d != 255 on %s\n",
687 		    ip6->ip6_hlim,
688 		    m->m_pkthdr.rcvif->if_xname);
689 		m_freem(m);
690 		return (IPPROTO_DONE);
691 	}
692 
693 	/* verify that we have a complete carp packet */
694 	len = m->m_len;
695 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
696 	if (ch == NULL) {
697 		CARPSTATS_INC(carps_badlen);
698 		CARP_DEBUG("carp6_input: packet size %u too small\n", len);
699 		return (IPPROTO_DONE);
700 	}
701 
702 
703 	/* verify the CARP checksum */
704 	m->m_data += *offp;
705 	if (carp_cksum(m, sizeof(*ch))) {
706 		CARPSTATS_INC(carps_badsum);
707 		CARP_DEBUG("carp6_input: checksum failed, on %s\n",
708 		    m->m_pkthdr.rcvif->if_xname);
709 		m_freem(m);
710 		return (IPPROTO_DONE);
711 	}
712 	m->m_data -= *offp;
713 
714 	carp_input_c(m, ch, AF_INET6);
715 	return (IPPROTO_DONE);
716 }
717 #endif /* INET6 */
718 
719 static void
720 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
721 {
722 	struct ifnet *ifp = m->m_pkthdr.rcvif;
723 	struct carp_softc *sc;
724 	u_int64_t tmp_counter;
725 	struct timeval sc_tv, ch_tv;
726 
727 	/* verify that the VHID is valid on the receiving interface */
728 	CARP_LOCK(ifp->if_carp);
729 	TAILQ_FOREACH(sc, &((struct carp_if *)ifp->if_carp)->vhif_vrs, sc_list)
730 		if (sc->sc_vhid == ch->carp_vhid)
731 			break;
732 
733 	if (!sc || !((SC2IFP(sc)->if_flags & IFF_UP) &&
734 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
735 		CARPSTATS_INC(carps_badvhid);
736 		CARP_UNLOCK(ifp->if_carp);
737 		m_freem(m);
738 		return;
739 	}
740 
741 	getmicrotime(&SC2IFP(sc)->if_lastchange);
742 	SC2IFP(sc)->if_ipackets++;
743 	SC2IFP(sc)->if_ibytes += m->m_pkthdr.len;
744 
745 	if (bpf_peers_present(SC2IFP(sc)->if_bpf)) {
746 		uint32_t af1 = af;
747 #ifdef INET
748 		struct ip *ip = mtod(m, struct ip *);
749 
750 		/* BPF wants net byte order */
751 		if (af == AF_INET) {
752 			ip->ip_len = htons(ip->ip_len + (ip->ip_hl << 2));
753 			ip->ip_off = htons(ip->ip_off);
754 		}
755 #endif
756 		bpf_mtap2(SC2IFP(sc)->if_bpf, &af1, sizeof(af1), m);
757 	}
758 
759 	/* verify the CARP version. */
760 	if (ch->carp_version != CARP_VERSION) {
761 		CARPSTATS_INC(carps_badver);
762 		SC2IFP(sc)->if_ierrors++;
763 		CARP_UNLOCK(ifp->if_carp);
764 		CARP_DEBUG("%s; invalid version %d\n",
765 		    SC2IFP(sc)->if_xname,
766 		    ch->carp_version);
767 		m_freem(m);
768 		return;
769 	}
770 
771 	/* verify the hash */
772 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
773 		CARPSTATS_INC(carps_badauth);
774 		SC2IFP(sc)->if_ierrors++;
775 		CARP_UNLOCK(ifp->if_carp);
776 		CARP_DEBUG("%s: incorrect hash\n", SC2IFP(sc)->if_xname);
777 		m_freem(m);
778 		return;
779 	}
780 
781 	tmp_counter = ntohl(ch->carp_counter[0]);
782 	tmp_counter = tmp_counter<<32;
783 	tmp_counter += ntohl(ch->carp_counter[1]);
784 
785 	/* XXX Replay protection goes here */
786 
787 	sc->sc_init_counter = 0;
788 	sc->sc_counter = tmp_counter;
789 
790 	sc_tv.tv_sec = sc->sc_advbase;
791 	if (carp_suppress_preempt && sc->sc_advskew <  240)
792 		sc_tv.tv_usec = 240 * 1000000 / 256;
793 	else
794 		sc_tv.tv_usec = sc->sc_advskew * 1000000 / 256;
795 	ch_tv.tv_sec = ch->carp_advbase;
796 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
797 
798 	switch (sc->sc_state) {
799 	case INIT:
800 		break;
801 	case MASTER:
802 		/*
803 		 * If we receive an advertisement from a master who's going to
804 		 * be more frequent than us, go into BACKUP state.
805 		 */
806 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
807 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
808 			callout_stop(&sc->sc_ad_tmo);
809 			CARP_LOG("%s: MASTER -> BACKUP "
810 			   "(more frequent advertisement received)\n",
811 			   SC2IFP(sc)->if_xname);
812 			carp_set_state(sc, BACKUP);
813 			carp_setrun(sc, 0);
814 			carp_setroute(sc, RTM_DELETE);
815 		}
816 		break;
817 	case BACKUP:
818 		/*
819 		 * If we're pre-empting masters who advertise slower than us,
820 		 * and this one claims to be slower, treat him as down.
821 		 */
822 		if (carp_opts[CARPCTL_PREEMPT] &&
823 		    timevalcmp(&sc_tv, &ch_tv, <)) {
824 			CARP_LOG("%s: BACKUP -> MASTER "
825 			    "(preempting a slower master)\n",
826 			    SC2IFP(sc)->if_xname);
827 			carp_master_down_locked(sc);
828 			break;
829 		}
830 
831 		/*
832 		 *  If the master is going to advertise at such a low frequency
833 		 *  that he's guaranteed to time out, we'd might as well just
834 		 *  treat him as timed out now.
835 		 */
836 		sc_tv.tv_sec = sc->sc_advbase * 3;
837 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
838 			CARP_LOG("%s: BACKUP -> MASTER "
839 			    "(master timed out)\n",
840 			    SC2IFP(sc)->if_xname);
841 			carp_master_down_locked(sc);
842 			break;
843 		}
844 
845 		/*
846 		 * Otherwise, we reset the counter and wait for the next
847 		 * advertisement.
848 		 */
849 		carp_setrun(sc, af);
850 		break;
851 	}
852 
853 	CARP_UNLOCK(ifp->if_carp);
854 
855 	m_freem(m);
856 	return;
857 }
858 
859 static int
860 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
861 {
862 	struct m_tag *mtag;
863 	struct ifnet *ifp = SC2IFP(sc);
864 
865 	if (sc->sc_init_counter) {
866 		/* this could also be seconds since unix epoch */
867 		sc->sc_counter = arc4random();
868 		sc->sc_counter = sc->sc_counter << 32;
869 		sc->sc_counter += arc4random();
870 	} else
871 		sc->sc_counter++;
872 
873 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
874 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
875 
876 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
877 
878 	/* Tag packet for carp_output */
879 	mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct ifnet *), M_NOWAIT);
880 	if (mtag == NULL) {
881 		m_freem(m);
882 		SC2IFP(sc)->if_oerrors++;
883 		return (ENOMEM);
884 	}
885 	bcopy(&ifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *));
886 	m_tag_prepend(m, mtag);
887 
888 	return (0);
889 }
890 
891 static void
892 carp_send_ad_all(void)
893 {
894 	struct carp_softc *sc;
895 
896 	mtx_lock(&carp_mtx);
897 	LIST_FOREACH(sc, &carpif_list, sc_next) {
898 		if (sc->sc_carpdev == NULL)
899 			continue;
900 		CARP_SCLOCK(sc);
901 		if ((SC2IFP(sc)->if_flags & IFF_UP) &&
902 		    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING) &&
903 		     sc->sc_state == MASTER)
904 			carp_send_ad_locked(sc);
905 		CARP_SCUNLOCK(sc);
906 	}
907 	mtx_unlock(&carp_mtx);
908 }
909 
910 static void
911 carp_send_ad(void *v)
912 {
913 	struct carp_softc *sc = v;
914 
915 	CARP_SCLOCK(sc);
916 	carp_send_ad_locked(sc);
917 	CARP_SCUNLOCK(sc);
918 }
919 
920 static void
921 carp_send_ad_locked(struct carp_softc *sc)
922 {
923 	struct carp_header ch;
924 	struct timeval tv;
925 	struct carp_header *ch_ptr;
926 	struct mbuf *m;
927 	int len, advbase, advskew;
928 
929 	CARP_SCLOCK_ASSERT(sc);
930 
931 	/* bow out if we've lost our UPness or RUNNINGuiness */
932 	if (!((SC2IFP(sc)->if_flags & IFF_UP) &&
933 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
934 		advbase = 255;
935 		advskew = 255;
936 	} else {
937 		advbase = sc->sc_advbase;
938 		if (!carp_suppress_preempt || sc->sc_advskew > 240)
939 			advskew = sc->sc_advskew;
940 		else
941 			advskew = 240;
942 		tv.tv_sec = advbase;
943 		tv.tv_usec = advskew * 1000000 / 256;
944 	}
945 
946 	ch.carp_version = CARP_VERSION;
947 	ch.carp_type = CARP_ADVERTISEMENT;
948 	ch.carp_vhid = sc->sc_vhid;
949 	ch.carp_advbase = advbase;
950 	ch.carp_advskew = advskew;
951 	ch.carp_authlen = 7;	/* XXX DEFINE */
952 	ch.carp_pad1 = 0;	/* must be zero */
953 	ch.carp_cksum = 0;
954 
955 #ifdef INET
956 	if (sc->sc_ia) {
957 		struct ip *ip;
958 
959 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
960 		if (m == NULL) {
961 			SC2IFP(sc)->if_oerrors++;
962 			CARPSTATS_INC(carps_onomem);
963 			/* XXX maybe less ? */
964 			if (advbase != 255 || advskew != 255)
965 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
966 				    carp_send_ad, sc);
967 			return;
968 		}
969 		len = sizeof(*ip) + sizeof(ch);
970 		m->m_pkthdr.len = len;
971 		m->m_pkthdr.rcvif = NULL;
972 		m->m_len = len;
973 		MH_ALIGN(m, m->m_len);
974 		m->m_flags |= M_MCAST;
975 		ip = mtod(m, struct ip *);
976 		ip->ip_v = IPVERSION;
977 		ip->ip_hl = sizeof(*ip) >> 2;
978 		ip->ip_tos = IPTOS_LOWDELAY;
979 		ip->ip_len = len;
980 		ip->ip_id = ip_newid();
981 		ip->ip_off = IP_DF;
982 		ip->ip_ttl = CARP_DFLTTL;
983 		ip->ip_p = IPPROTO_CARP;
984 		ip->ip_sum = 0;
985 		ip->ip_src.s_addr = sc->sc_ia->ia_addr.sin_addr.s_addr;
986 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
987 
988 		ch_ptr = (struct carp_header *)(&ip[1]);
989 		bcopy(&ch, ch_ptr, sizeof(ch));
990 		if (carp_prepare_ad(m, sc, ch_ptr))
991 			return;
992 
993 		m->m_data += sizeof(*ip);
994 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip));
995 		m->m_data -= sizeof(*ip);
996 
997 		getmicrotime(&SC2IFP(sc)->if_lastchange);
998 		SC2IFP(sc)->if_opackets++;
999 		SC2IFP(sc)->if_obytes += len;
1000 		CARPSTATS_INC(carps_opackets);
1001 
1002 		if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)) {
1003 			SC2IFP(sc)->if_oerrors++;
1004 			if (sc->sc_sendad_errors < INT_MAX)
1005 				sc->sc_sendad_errors++;
1006 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
1007 				carp_suppress_preempt++;
1008 				if (carp_suppress_preempt == 1) {
1009 					CARP_SCUNLOCK(sc);
1010 					carp_send_ad_all();
1011 					CARP_SCLOCK(sc);
1012 				}
1013 			}
1014 			sc->sc_sendad_success = 0;
1015 		} else {
1016 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1017 				if (++sc->sc_sendad_success >=
1018 				    CARP_SENDAD_MIN_SUCCESS) {
1019 					carp_suppress_preempt--;
1020 					sc->sc_sendad_errors = 0;
1021 				}
1022 			} else
1023 				sc->sc_sendad_errors = 0;
1024 		}
1025 	}
1026 #endif /* INET */
1027 #ifdef INET6
1028 	if (sc->sc_ia6) {
1029 		struct ip6_hdr *ip6;
1030 
1031 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
1032 		if (m == NULL) {
1033 			SC2IFP(sc)->if_oerrors++;
1034 			CARPSTATS_INC(carps_onomem);
1035 			/* XXX maybe less ? */
1036 			if (advbase != 255 || advskew != 255)
1037 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1038 				    carp_send_ad, sc);
1039 			return;
1040 		}
1041 		len = sizeof(*ip6) + sizeof(ch);
1042 		m->m_pkthdr.len = len;
1043 		m->m_pkthdr.rcvif = NULL;
1044 		m->m_len = len;
1045 		MH_ALIGN(m, m->m_len);
1046 		m->m_flags |= M_MCAST;
1047 		ip6 = mtod(m, struct ip6_hdr *);
1048 		bzero(ip6, sizeof(*ip6));
1049 		ip6->ip6_vfc |= IPV6_VERSION;
1050 		ip6->ip6_hlim = CARP_DFLTTL;
1051 		ip6->ip6_nxt = IPPROTO_CARP;
1052 		bcopy(&sc->sc_ia6->ia_addr.sin6_addr, &ip6->ip6_src,
1053 		    sizeof(struct in6_addr));
1054 		/* set the multicast destination */
1055 
1056 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1057 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1058 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1059 			SC2IFP(sc)->if_oerrors++;
1060 			m_freem(m);
1061 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1062 			return;
1063 		}
1064 
1065 		ch_ptr = (struct carp_header *)(&ip6[1]);
1066 		bcopy(&ch, ch_ptr, sizeof(ch));
1067 		if (carp_prepare_ad(m, sc, ch_ptr))
1068 			return;
1069 
1070 		m->m_data += sizeof(*ip6);
1071 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip6));
1072 		m->m_data -= sizeof(*ip6);
1073 
1074 		getmicrotime(&SC2IFP(sc)->if_lastchange);
1075 		SC2IFP(sc)->if_opackets++;
1076 		SC2IFP(sc)->if_obytes += len;
1077 		CARPSTATS_INC(carps_opackets6);
1078 
1079 		if (ip6_output(m, NULL, NULL, 0, &sc->sc_im6o, NULL, NULL)) {
1080 			SC2IFP(sc)->if_oerrors++;
1081 			if (sc->sc_sendad_errors < INT_MAX)
1082 				sc->sc_sendad_errors++;
1083 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
1084 				carp_suppress_preempt++;
1085 				if (carp_suppress_preempt == 1) {
1086 					CARP_SCUNLOCK(sc);
1087 					carp_send_ad_all();
1088 					CARP_SCLOCK(sc);
1089 				}
1090 			}
1091 			sc->sc_sendad_success = 0;
1092 		} else {
1093 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1094 				if (++sc->sc_sendad_success >=
1095 				    CARP_SENDAD_MIN_SUCCESS) {
1096 					carp_suppress_preempt--;
1097 					sc->sc_sendad_errors = 0;
1098 				}
1099 			} else
1100 				sc->sc_sendad_errors = 0;
1101 		}
1102 	}
1103 #endif /* INET6 */
1104 
1105 	if (advbase != 255 || advskew != 255)
1106 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1107 		    carp_send_ad, sc);
1108 
1109 }
1110 
1111 #ifdef INET
1112 /*
1113  * Broadcast a gratuitous ARP request containing
1114  * the virtual router MAC address for each IP address
1115  * associated with the virtual router.
1116  */
1117 static void
1118 carp_send_arp(struct carp_softc *sc)
1119 {
1120 	struct ifaddr *ifa;
1121 
1122 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1123 
1124 		if (ifa->ifa_addr->sa_family != AF_INET)
1125 			continue;
1126 
1127 /*		arprequest(sc->sc_carpdev, &in, &in, IF_LLADDR(sc->sc_ifp)); */
1128 		arp_ifinit2(sc->sc_carpdev, ifa, IF_LLADDR(sc->sc_ifp));
1129 
1130 		DELAY(1000);	/* XXX */
1131 	}
1132 }
1133 #endif
1134 
1135 #ifdef INET6
1136 static void
1137 carp_send_na(struct carp_softc *sc)
1138 {
1139 	struct ifaddr *ifa;
1140 	struct in6_addr *in6;
1141 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1142 
1143 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1144 
1145 		if (ifa->ifa_addr->sa_family != AF_INET6)
1146 			continue;
1147 
1148 		in6 = &ifatoia6(ifa)->ia_addr.sin6_addr;
1149 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1150 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1151 		DELAY(1000);	/* XXX */
1152 	}
1153 }
1154 #endif /* INET6 */
1155 
1156 #ifdef INET
1157 static int
1158 carp_addrcount(struct carp_if *cif, struct in_ifaddr *ia, int type)
1159 {
1160 	struct carp_softc *vh;
1161 	struct ifaddr *ifa;
1162 	int count = 0;
1163 
1164 	CARP_LOCK_ASSERT(cif);
1165 
1166 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1167 		if ((type == CARP_COUNT_RUNNING &&
1168 		    (SC2IFP(vh)->if_flags & IFF_UP) &&
1169 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) ||
1170 		    (type == CARP_COUNT_MASTER && vh->sc_state == MASTER)) {
1171 			IF_ADDR_LOCK(SC2IFP(vh));
1172 			TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1173 			    ifa_list) {
1174 				if (ifa->ifa_addr->sa_family == AF_INET &&
1175 				    ia->ia_addr.sin_addr.s_addr ==
1176 				    ifatoia(ifa)->ia_addr.sin_addr.s_addr)
1177 					count++;
1178 			}
1179 			IF_ADDR_UNLOCK(SC2IFP(vh));
1180 		}
1181 	}
1182 	return (count);
1183 }
1184 
1185 int
1186 carp_iamatch(struct ifnet *ifp, struct in_ifaddr *ia,
1187     struct in_addr *isaddr, u_int8_t **enaddr)
1188 {
1189 	struct carp_if *cif;
1190 	struct carp_softc *vh;
1191 	int index, count = 0;
1192 	struct ifaddr *ifa;
1193 
1194 	cif = ifp->if_carp;
1195 	CARP_LOCK(cif);
1196 
1197 	if (carp_opts[CARPCTL_ARPBALANCE]) {
1198 		/*
1199 		 * XXX proof of concept implementation.
1200 		 * We use the source ip to decide which virtual host should
1201 		 * handle the request. If we're master of that virtual host,
1202 		 * then we respond, otherwise, just drop the arp packet on
1203 		 * the floor.
1204 		 */
1205 		count = carp_addrcount(cif, ia, CARP_COUNT_RUNNING);
1206 		if (count == 0) {
1207 			/* should never reach this */
1208 			CARP_UNLOCK(cif);
1209 			return (0);
1210 		}
1211 
1212 		/* this should be a hash, like pf_hash() */
1213 		index = ntohl(isaddr->s_addr) % count;
1214 		count = 0;
1215 
1216 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1217 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1218 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) {
1219 				IF_ADDR_LOCK(SC2IFP(vh));
1220 				TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1221 				    ifa_list) {
1222 					if (ifa->ifa_addr->sa_family ==
1223 					    AF_INET &&
1224 					    ia->ia_addr.sin_addr.s_addr ==
1225 					    ifatoia(ifa)->ia_addr.sin_addr.s_addr) {
1226 						if (count == index) {
1227 							if (vh->sc_state ==
1228 							    MASTER) {
1229 								*enaddr = IF_LLADDR(vh->sc_ifp);
1230 								IF_ADDR_UNLOCK(SC2IFP(vh));
1231 								CARP_UNLOCK(cif);
1232 								return (1);
1233 							} else {
1234 								IF_ADDR_UNLOCK(SC2IFP(vh));
1235 								CARP_UNLOCK(cif);
1236 								return (0);
1237 							}
1238 						}
1239 						count++;
1240 					}
1241 				}
1242 				IF_ADDR_UNLOCK(SC2IFP(vh));
1243 			}
1244 		}
1245 	} else {
1246 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1247 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1248 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1249 			    ia->ia_ifp == SC2IFP(vh) &&
1250 			    vh->sc_state == MASTER) {
1251 				*enaddr = IF_LLADDR(vh->sc_ifp);
1252 				CARP_UNLOCK(cif);
1253 				return (1);
1254 			}
1255 		}
1256 	}
1257 	CARP_UNLOCK(cif);
1258 	return (0);
1259 }
1260 #endif
1261 
1262 #ifdef INET6
1263 struct ifaddr *
1264 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1265 {
1266 	struct carp_if *cif;
1267 	struct carp_softc *vh;
1268 	struct ifaddr *ifa;
1269 
1270 	cif = ifp->if_carp;
1271 	CARP_LOCK(cif);
1272 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1273 		IF_ADDR_LOCK(SC2IFP(vh));
1274 		TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist, ifa_list) {
1275 			if (IN6_ARE_ADDR_EQUAL(taddr,
1276 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1277  			    (SC2IFP(vh)->if_flags & IFF_UP) &&
1278 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1279 			    vh->sc_state == MASTER) {
1280 				ifa_ref(ifa);
1281 				IF_ADDR_UNLOCK(SC2IFP(vh));
1282 			    	CARP_UNLOCK(cif);
1283 				return (ifa);
1284 			}
1285 		}
1286 		IF_ADDR_UNLOCK(SC2IFP(vh));
1287 	}
1288 	CARP_UNLOCK(cif);
1289 
1290 	return (NULL);
1291 }
1292 
1293 caddr_t
1294 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1295 {
1296 	struct m_tag *mtag;
1297 	struct carp_if *cif;
1298 	struct carp_softc *sc;
1299 	struct ifaddr *ifa;
1300 
1301 	cif = ifp->if_carp;
1302 	CARP_LOCK(cif);
1303 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
1304 		IF_ADDR_LOCK(SC2IFP(sc));
1305 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1306 			if (IN6_ARE_ADDR_EQUAL(taddr,
1307 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1308  			    (SC2IFP(sc)->if_flags & IFF_UP) &&
1309 			    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING)) {
1310 				struct ifnet *ifp = SC2IFP(sc);
1311 				mtag = m_tag_get(PACKET_TAG_CARP,
1312 				    sizeof(struct ifnet *), M_NOWAIT);
1313 				if (mtag == NULL) {
1314 					/* better a bit than nothing */
1315 					IF_ADDR_UNLOCK(SC2IFP(sc));
1316 					CARP_UNLOCK(cif);
1317 					return (IF_LLADDR(sc->sc_ifp));
1318 				}
1319 				bcopy(&ifp, (caddr_t)(mtag + 1),
1320 				    sizeof(struct ifnet *));
1321 				m_tag_prepend(m, mtag);
1322 
1323 				IF_ADDR_UNLOCK(SC2IFP(sc));
1324 				CARP_UNLOCK(cif);
1325 				return (IF_LLADDR(sc->sc_ifp));
1326 			}
1327 		}
1328 		IF_ADDR_UNLOCK(SC2IFP(sc));
1329 	}
1330 	CARP_UNLOCK(cif);
1331 
1332 	return (NULL);
1333 }
1334 #endif
1335 
1336 struct ifnet *
1337 carp_forus(struct ifnet *ifp, u_char *dhost)
1338 {
1339 	struct carp_if *cif;
1340 	struct carp_softc *vh;
1341 	u_int8_t *ena = dhost;
1342 
1343 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1344 		return (NULL);
1345 
1346 	cif = ifp->if_carp;
1347 	CARP_LOCK(cif);
1348 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list)
1349 		if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1350 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1351 		    vh->sc_state == MASTER &&
1352 		    !bcmp(dhost, IF_LLADDR(vh->sc_ifp), ETHER_ADDR_LEN)) {
1353 		    	CARP_UNLOCK(cif);
1354 			return (SC2IFP(vh));
1355 		}
1356 
1357     	CARP_UNLOCK(cif);
1358 	return (NULL);
1359 }
1360 
1361 static void
1362 carp_master_down(void *v)
1363 {
1364 	struct carp_softc *sc = v;
1365 
1366 	CARP_SCLOCK(sc);
1367 	carp_master_down_locked(sc);
1368 	CARP_SCUNLOCK(sc);
1369 }
1370 
1371 static void
1372 carp_master_down_locked(struct carp_softc *sc)
1373 {
1374 	if (sc->sc_carpdev)
1375 		CARP_SCLOCK_ASSERT(sc);
1376 
1377 	switch (sc->sc_state) {
1378 	case INIT:
1379 		printf("%s: master_down event in INIT state\n",
1380 		    SC2IFP(sc)->if_xname);
1381 		break;
1382 	case MASTER:
1383 		break;
1384 	case BACKUP:
1385 		carp_set_state(sc, MASTER);
1386 		carp_send_ad_locked(sc);
1387 #ifdef INET
1388 		carp_send_arp(sc);
1389 #endif
1390 #ifdef INET6
1391 		carp_send_na(sc);
1392 #endif /* INET6 */
1393 		carp_setrun(sc, 0);
1394 		carp_setroute(sc, RTM_ADD);
1395 		break;
1396 	}
1397 }
1398 
1399 /*
1400  * When in backup state, af indicates whether to reset the master down timer
1401  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1402  */
1403 static void
1404 carp_setrun(struct carp_softc *sc, sa_family_t af)
1405 {
1406 	struct timeval tv;
1407 
1408 	if (sc->sc_carpdev == NULL) {
1409 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1410 		carp_set_state(sc, INIT);
1411 		return;
1412 	} else
1413 		CARP_SCLOCK_ASSERT(sc);
1414 
1415 	if (SC2IFP(sc)->if_flags & IFF_UP &&
1416 	    sc->sc_vhid > 0 && (sc->sc_naddrs || sc->sc_naddrs6) &&
1417 	    sc->sc_carpdev->if_link_state == LINK_STATE_UP)
1418 		SC2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
1419 	else {
1420 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1421 		carp_setroute(sc, RTM_DELETE);
1422 		return;
1423 	}
1424 
1425 	switch (sc->sc_state) {
1426 	case INIT:
1427 		CARP_LOG("%s: INIT -> BACKUP\n", SC2IFP(sc)->if_xname);
1428 		carp_set_state(sc, BACKUP);
1429 		carp_setroute(sc, RTM_DELETE);
1430 		carp_setrun(sc, 0);
1431 		break;
1432 	case BACKUP:
1433 		callout_stop(&sc->sc_ad_tmo);
1434 		tv.tv_sec = 3 * sc->sc_advbase;
1435 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1436 		switch (af) {
1437 #ifdef INET
1438 		case AF_INET:
1439 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1440 			    carp_master_down, sc);
1441 			break;
1442 #endif /* INET */
1443 #ifdef INET6
1444 		case AF_INET6:
1445 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1446 			    carp_master_down, sc);
1447 			break;
1448 #endif /* INET6 */
1449 		default:
1450 			if (sc->sc_naddrs)
1451 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1452 				    carp_master_down, sc);
1453 			if (sc->sc_naddrs6)
1454 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1455 				    carp_master_down, sc);
1456 			break;
1457 		}
1458 		break;
1459 	case MASTER:
1460 		tv.tv_sec = sc->sc_advbase;
1461 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1462 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1463 		    carp_send_ad, sc);
1464 		break;
1465 	}
1466 }
1467 
1468 #ifdef INET
1469 static void
1470 carp_multicast_cleanup(struct carp_softc *sc, int dofree)
1471 {
1472 	struct ip_moptions *imo = &sc->sc_imo;
1473 	u_int16_t n = imo->imo_num_memberships;
1474 
1475 	/* Clean up our own multicast memberships */
1476 	while (n-- > 0) {
1477 		if (imo->imo_membership[n] != NULL) {
1478 			if (dofree)
1479 				in_delmulti(imo->imo_membership[n]);
1480 			imo->imo_membership[n] = NULL;
1481 		}
1482 	}
1483 	KASSERT(imo->imo_mfilters == NULL,
1484 	   ("%s: imo_mfilters != NULL", __func__));
1485 	imo->imo_num_memberships = 0;
1486 	imo->imo_multicast_ifp = NULL;
1487 }
1488 #endif
1489 
1490 #ifdef INET6
1491 static void
1492 carp_multicast6_cleanup(struct carp_softc *sc, int dofree)
1493 {
1494 	struct ip6_moptions *im6o = &sc->sc_im6o;
1495 	u_int16_t n = im6o->im6o_num_memberships;
1496 
1497 	while (n-- > 0) {
1498 		if (im6o->im6o_membership[n] != NULL) {
1499 			if (dofree)
1500 				in6_mc_leave(im6o->im6o_membership[n], NULL);
1501 			im6o->im6o_membership[n] = NULL;
1502 		}
1503 	}
1504 	KASSERT(im6o->im6o_mfilters == NULL,
1505 	   ("%s: im6o_mfilters != NULL", __func__));
1506 	im6o->im6o_num_memberships = 0;
1507 	im6o->im6o_multicast_ifp = NULL;
1508 }
1509 #endif
1510 
1511 #ifdef INET
1512 static int
1513 carp_set_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1514 {
1515 	struct ifnet *ifp;
1516 	struct carp_if *cif;
1517 	struct in_ifaddr *ia, *ia_if;
1518 	struct ip_moptions *imo = &sc->sc_imo;
1519 	struct in_addr addr;
1520 	u_long iaddr = htonl(sin->sin_addr.s_addr);
1521 	int own, error;
1522 
1523 	if (sin->sin_addr.s_addr == 0) {
1524 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1525 			carp_set_state(sc, INIT);
1526 		if (sc->sc_naddrs)
1527 			SC2IFP(sc)->if_flags |= IFF_UP;
1528 		if (sc->sc_carpdev)
1529 			CARP_SCLOCK(sc);
1530 		carp_setrun(sc, 0);
1531 		if (sc->sc_carpdev)
1532 			CARP_SCUNLOCK(sc);
1533 		return (0);
1534 	}
1535 
1536 	/* we have to do it by hands to check we won't match on us */
1537 	ia_if = NULL; own = 0;
1538 	IN_IFADDR_RLOCK();
1539 	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
1540 		/* and, yeah, we need a multicast-capable iface too */
1541 		if (ia->ia_ifp != SC2IFP(sc) &&
1542 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1543 		    (iaddr & ia->ia_subnetmask) == ia->ia_subnet) {
1544 			if (!ia_if)
1545 				ia_if = ia;
1546 			if (sin->sin_addr.s_addr ==
1547 			    ia->ia_addr.sin_addr.s_addr)
1548 				own++;
1549 		}
1550 	}
1551 
1552 	if (!ia_if) {
1553 		IN_IFADDR_RUNLOCK();
1554 		return (EADDRNOTAVAIL);
1555 	}
1556 
1557 	ia = ia_if;
1558 	ifa_ref(&ia->ia_ifa);
1559 	IN_IFADDR_RUNLOCK();
1560 
1561 	ifp = ia->ia_ifp;
1562 
1563 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1564 	    (imo->imo_multicast_ifp && imo->imo_multicast_ifp != ifp)) {
1565 		ifa_free(&ia->ia_ifa);
1566 		return (EADDRNOTAVAIL);
1567 	}
1568 
1569 	if (imo->imo_num_memberships == 0) {
1570 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1571 		if ((imo->imo_membership[0] = in_addmulti(&addr, ifp)) ==
1572 		    NULL) {
1573 			ifa_free(&ia->ia_ifa);
1574 			return (ENOBUFS);
1575 		}
1576 		imo->imo_num_memberships++;
1577 		imo->imo_multicast_ifp = ifp;
1578 		imo->imo_multicast_ttl = CARP_DFLTTL;
1579 		imo->imo_multicast_loop = 0;
1580 	}
1581 
1582 	if (!ifp->if_carp) {
1583 
1584 		cif = malloc(sizeof(*cif), M_CARP,
1585 		    M_WAITOK|M_ZERO);
1586 		if (!cif) {
1587 			error = ENOBUFS;
1588 			goto cleanup;
1589 		}
1590 		if ((error = ifpromisc(ifp, 1))) {
1591 			free(cif, M_CARP);
1592 			goto cleanup;
1593 		}
1594 
1595 		CARP_LOCK_INIT(cif);
1596 		CARP_LOCK(cif);
1597 		cif->vhif_ifp = ifp;
1598 		TAILQ_INIT(&cif->vhif_vrs);
1599 		ifp->if_carp = cif;
1600 
1601 	} else {
1602 		struct carp_softc *vr;
1603 
1604 		cif = (struct carp_if *)ifp->if_carp;
1605 		CARP_LOCK(cif);
1606 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1607 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1608 				CARP_UNLOCK(cif);
1609 				error = EEXIST;
1610 				goto cleanup;
1611 			}
1612 	}
1613 	sc->sc_ia = ia;
1614 	sc->sc_carpdev = ifp;
1615 
1616 	{ /* XXX prevent endless loop if already in queue */
1617 	struct carp_softc *vr, *after = NULL;
1618 	int myself = 0;
1619 	cif = (struct carp_if *)ifp->if_carp;
1620 
1621 	/* XXX: cif should not change, right? So we still hold the lock */
1622 	CARP_LOCK_ASSERT(cif);
1623 
1624 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1625 		if (vr == sc)
1626 			myself = 1;
1627 		if (vr->sc_vhid < sc->sc_vhid)
1628 			after = vr;
1629 	}
1630 
1631 	if (!myself) {
1632 		/* We're trying to keep things in order */
1633 		if (after == NULL) {
1634 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1635 		} else {
1636 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1637 		}
1638 		cif->vhif_nvrs++;
1639 	}
1640 	}
1641 
1642 	sc->sc_naddrs++;
1643 	SC2IFP(sc)->if_flags |= IFF_UP;
1644 	if (own)
1645 		sc->sc_advskew = 0;
1646 	carp_sc_state_locked(sc);
1647 	carp_setrun(sc, 0);
1648 
1649 	CARP_UNLOCK(cif);
1650 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1651 
1652 	return (0);
1653 
1654 cleanup:
1655 	in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1656 	ifa_free(&ia->ia_ifa);
1657 	return (error);
1658 }
1659 
1660 static int
1661 carp_del_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1662 {
1663 	int error = 0;
1664 
1665 	if (!--sc->sc_naddrs) {
1666 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1667 		struct ip_moptions *imo = &sc->sc_imo;
1668 
1669 		CARP_LOCK(cif);
1670 		callout_stop(&sc->sc_ad_tmo);
1671 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1672 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1673 		sc->sc_vhid = -1;
1674 		in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1675 		imo->imo_multicast_ifp = NULL;
1676 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1677 		if (!--cif->vhif_nvrs) {
1678 			sc->sc_carpdev->if_carp = NULL;
1679 			CARP_LOCK_DESTROY(cif);
1680 			free(cif, M_CARP);
1681 		} else {
1682 			CARP_UNLOCK(cif);
1683 		}
1684 	}
1685 
1686 	return (error);
1687 }
1688 #endif
1689 
1690 #ifdef INET6
1691 static int
1692 carp_set_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1693 {
1694 	struct ifnet *ifp;
1695 	struct carp_if *cif;
1696 	struct in6_ifaddr *ia, *ia_if;
1697 	struct ip6_moptions *im6o = &sc->sc_im6o;
1698 	struct in6_addr in6;
1699 	int own, error;
1700 
1701 	error = 0;
1702 
1703 	if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
1704 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1705 			carp_set_state(sc, INIT);
1706 		if (sc->sc_naddrs6)
1707 			SC2IFP(sc)->if_flags |= IFF_UP;
1708 		if (sc->sc_carpdev)
1709 			CARP_SCLOCK(sc);
1710 		carp_setrun(sc, 0);
1711 		if (sc->sc_carpdev)
1712 			CARP_SCUNLOCK(sc);
1713 		return (0);
1714 	}
1715 
1716 	/* we have to do it by hands to check we won't match on us */
1717 	ia_if = NULL; own = 0;
1718 	IN6_IFADDR_RLOCK();
1719 	TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
1720 		int i;
1721 
1722 		for (i = 0; i < 4; i++) {
1723 			if ((sin6->sin6_addr.s6_addr32[i] &
1724 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]) !=
1725 			    (ia->ia_addr.sin6_addr.s6_addr32[i] &
1726 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]))
1727 				break;
1728 		}
1729 		/* and, yeah, we need a multicast-capable iface too */
1730 		if (ia->ia_ifp != SC2IFP(sc) &&
1731 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1732 		    (i == 4)) {
1733 			if (!ia_if)
1734 				ia_if = ia;
1735 			if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr,
1736 			    &ia->ia_addr.sin6_addr))
1737 				own++;
1738 		}
1739 	}
1740 
1741 	if (!ia_if) {
1742 		IN6_IFADDR_RUNLOCK();
1743 		return (EADDRNOTAVAIL);
1744 	}
1745 	ia = ia_if;
1746 	ifa_ref(&ia->ia_ifa);
1747 	IN6_IFADDR_RUNLOCK();
1748 	ifp = ia->ia_ifp;
1749 
1750 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1751 	    (im6o->im6o_multicast_ifp && im6o->im6o_multicast_ifp != ifp)) {
1752 		ifa_free(&ia->ia_ifa);
1753 		return (EADDRNOTAVAIL);
1754 	}
1755 
1756 	if (!sc->sc_naddrs6) {
1757 		struct in6_multi *in6m;
1758 
1759 		im6o->im6o_multicast_ifp = ifp;
1760 
1761 		/* join CARP multicast address */
1762 		bzero(&in6, sizeof(in6));
1763 		in6.s6_addr16[0] = htons(0xff02);
1764 		in6.s6_addr8[15] = 0x12;
1765 		if (in6_setscope(&in6, ifp, NULL) != 0)
1766 			goto cleanup;
1767 		in6m = NULL;
1768 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1769 		if (error)
1770 			goto cleanup;
1771 		im6o->im6o_membership[0] = in6m;
1772 		im6o->im6o_num_memberships++;
1773 
1774 		/* join solicited multicast address */
1775 		bzero(&in6, sizeof(in6));
1776 		in6.s6_addr16[0] = htons(0xff02);
1777 		in6.s6_addr32[1] = 0;
1778 		in6.s6_addr32[2] = htonl(1);
1779 		in6.s6_addr32[3] = sin6->sin6_addr.s6_addr32[3];
1780 		in6.s6_addr8[12] = 0xff;
1781 		if (in6_setscope(&in6, ifp, NULL) != 0)
1782 			goto cleanup;
1783 		in6m = NULL;
1784 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1785 		if (error)
1786 			goto cleanup;
1787 		im6o->im6o_membership[1] = in6m;
1788 		im6o->im6o_num_memberships++;
1789 	}
1790 
1791 	if (!ifp->if_carp) {
1792 		cif = malloc(sizeof(*cif), M_CARP,
1793 		    M_WAITOK|M_ZERO);
1794 		if (!cif) {
1795 			error = ENOBUFS;
1796 			goto cleanup;
1797 		}
1798 		if ((error = ifpromisc(ifp, 1))) {
1799 			free(cif, M_CARP);
1800 			goto cleanup;
1801 		}
1802 
1803 		CARP_LOCK_INIT(cif);
1804 		CARP_LOCK(cif);
1805 		cif->vhif_ifp = ifp;
1806 		TAILQ_INIT(&cif->vhif_vrs);
1807 		ifp->if_carp = cif;
1808 
1809 	} else {
1810 		struct carp_softc *vr;
1811 
1812 		cif = (struct carp_if *)ifp->if_carp;
1813 		CARP_LOCK(cif);
1814 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1815 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1816 				CARP_UNLOCK(cif);
1817 				error = EINVAL;
1818 				goto cleanup;
1819 			}
1820 	}
1821 	sc->sc_ia6 = ia;
1822 	sc->sc_carpdev = ifp;
1823 
1824 	{ /* XXX prevent endless loop if already in queue */
1825 	struct carp_softc *vr, *after = NULL;
1826 	int myself = 0;
1827 	cif = (struct carp_if *)ifp->if_carp;
1828 	CARP_LOCK_ASSERT(cif);
1829 
1830 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1831 		if (vr == sc)
1832 			myself = 1;
1833 		if (vr->sc_vhid < sc->sc_vhid)
1834 			after = vr;
1835 	}
1836 
1837 	if (!myself) {
1838 		/* We're trying to keep things in order */
1839 		if (after == NULL) {
1840 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1841 		} else {
1842 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1843 		}
1844 		cif->vhif_nvrs++;
1845 	}
1846 	}
1847 
1848 	sc->sc_naddrs6++;
1849 	SC2IFP(sc)->if_flags |= IFF_UP;
1850 	if (own)
1851 		sc->sc_advskew = 0;
1852 	carp_sc_state_locked(sc);
1853 	carp_setrun(sc, 0);
1854 
1855 	CARP_UNLOCK(cif);
1856 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1857 
1858 	return (0);
1859 
1860 cleanup:
1861 	if (!sc->sc_naddrs6)
1862 		carp_multicast6_cleanup(sc, 1);
1863 	ifa_free(&ia->ia_ifa);
1864 	return (error);
1865 }
1866 
1867 static int
1868 carp_del_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1869 {
1870 	int error = 0;
1871 
1872 	if (!--sc->sc_naddrs6) {
1873 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1874 
1875 		CARP_LOCK(cif);
1876 		callout_stop(&sc->sc_ad_tmo);
1877 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1878 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1879 		sc->sc_vhid = -1;
1880 		carp_multicast6_cleanup(sc, 1);
1881 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1882 		if (!--cif->vhif_nvrs) {
1883 			CARP_LOCK_DESTROY(cif);
1884 			sc->sc_carpdev->if_carp = NULL;
1885 			free(cif, M_CARP);
1886 		} else
1887 			CARP_UNLOCK(cif);
1888 	}
1889 
1890 	return (error);
1891 }
1892 #endif /* INET6 */
1893 
1894 static int
1895 carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
1896 {
1897 	struct carp_softc *sc = ifp->if_softc, *vr;
1898 	struct carpreq carpr;
1899 	struct ifaddr *ifa;
1900 	struct ifreq *ifr;
1901 	struct ifaliasreq *ifra;
1902 	int locked = 0, error = 0;
1903 
1904 	ifa = (struct ifaddr *)addr;
1905 	ifra = (struct ifaliasreq *)addr;
1906 	ifr = (struct ifreq *)addr;
1907 
1908 	switch (cmd) {
1909 	case SIOCSIFADDR:
1910 		switch (ifa->ifa_addr->sa_family) {
1911 #ifdef INET
1912 		case AF_INET:
1913 			SC2IFP(sc)->if_flags |= IFF_UP;
1914 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1915 			    sizeof(struct sockaddr));
1916 			error = carp_set_addr(sc, satosin(ifa->ifa_addr));
1917 			break;
1918 #endif /* INET */
1919 #ifdef INET6
1920 		case AF_INET6:
1921 			SC2IFP(sc)->if_flags |= IFF_UP;
1922 			error = carp_set_addr6(sc, satosin6(ifa->ifa_addr));
1923 			break;
1924 #endif /* INET6 */
1925 		default:
1926 			error = EAFNOSUPPORT;
1927 			break;
1928 		}
1929 		break;
1930 
1931 	case SIOCAIFADDR:
1932 		switch (ifa->ifa_addr->sa_family) {
1933 #ifdef INET
1934 		case AF_INET:
1935 			SC2IFP(sc)->if_flags |= IFF_UP;
1936 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1937 			    sizeof(struct sockaddr));
1938 			error = carp_set_addr(sc, satosin(&ifra->ifra_addr));
1939 			break;
1940 #endif /* INET */
1941 #ifdef INET6
1942 		case AF_INET6:
1943 			SC2IFP(sc)->if_flags |= IFF_UP;
1944 			error = carp_set_addr6(sc, satosin6(&ifra->ifra_addr));
1945 			break;
1946 #endif /* INET6 */
1947 		default:
1948 			error = EAFNOSUPPORT;
1949 			break;
1950 		}
1951 		break;
1952 
1953 	case SIOCDIFADDR:
1954 		switch (ifa->ifa_addr->sa_family) {
1955 #ifdef INET
1956 		case AF_INET:
1957 			error = carp_del_addr(sc, satosin(&ifra->ifra_addr));
1958 			break;
1959 #endif /* INET */
1960 #ifdef INET6
1961 		case AF_INET6:
1962 			error = carp_del_addr6(sc, satosin6(&ifra->ifra_addr));
1963 			break;
1964 #endif /* INET6 */
1965 		default:
1966 			error = EAFNOSUPPORT;
1967 			break;
1968 		}
1969 		break;
1970 
1971 	case SIOCSIFFLAGS:
1972 		if (sc->sc_carpdev) {
1973 			locked = 1;
1974 			CARP_SCLOCK(sc);
1975 		}
1976 		if (sc->sc_state != INIT && !(ifr->ifr_flags & IFF_UP)) {
1977  			callout_stop(&sc->sc_ad_tmo);
1978  			callout_stop(&sc->sc_md_tmo);
1979  			callout_stop(&sc->sc_md6_tmo);
1980 			if (sc->sc_state == MASTER)
1981 				carp_send_ad_locked(sc);
1982 			carp_set_state(sc, INIT);
1983 			carp_setrun(sc, 0);
1984 		} else if (sc->sc_state == INIT && (ifr->ifr_flags & IFF_UP)) {
1985 			SC2IFP(sc)->if_flags |= IFF_UP;
1986 			carp_setrun(sc, 0);
1987 		}
1988 		break;
1989 
1990 	case SIOCSVH:
1991 		error = priv_check(curthread, PRIV_NETINET_CARP);
1992 		if (error)
1993 			break;
1994 		if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1995 			break;
1996 		error = 1;
1997 		if (sc->sc_carpdev) {
1998 			locked = 1;
1999 			CARP_SCLOCK(sc);
2000 		}
2001 		if (sc->sc_state != INIT && carpr.carpr_state != sc->sc_state) {
2002 			switch (carpr.carpr_state) {
2003 			case BACKUP:
2004 				callout_stop(&sc->sc_ad_tmo);
2005 				carp_set_state(sc, BACKUP);
2006 				carp_setrun(sc, 0);
2007 				carp_setroute(sc, RTM_DELETE);
2008 				break;
2009 			case MASTER:
2010 				carp_master_down_locked(sc);
2011 				break;
2012 			default:
2013 				break;
2014 			}
2015 		}
2016 		if (carpr.carpr_vhid > 0) {
2017 			if (carpr.carpr_vhid > 255) {
2018 				error = EINVAL;
2019 				break;
2020 			}
2021 			if (sc->sc_carpdev) {
2022 				struct carp_if *cif;
2023 				cif = (struct carp_if *)sc->sc_carpdev->if_carp;
2024 				TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
2025 					if (vr != sc &&
2026 					    vr->sc_vhid == carpr.carpr_vhid) {
2027 						error = EEXIST;
2028 						break;
2029 					}
2030 				if (error == EEXIST)
2031 					break;
2032 			}
2033 			sc->sc_vhid = carpr.carpr_vhid;
2034 			IF_LLADDR(sc->sc_ifp)[0] = 0;
2035 			IF_LLADDR(sc->sc_ifp)[1] = 0;
2036 			IF_LLADDR(sc->sc_ifp)[2] = 0x5e;
2037 			IF_LLADDR(sc->sc_ifp)[3] = 0;
2038 			IF_LLADDR(sc->sc_ifp)[4] = 1;
2039 			IF_LLADDR(sc->sc_ifp)[5] = sc->sc_vhid;
2040 			error--;
2041 		}
2042 		if (carpr.carpr_advbase > 0 || carpr.carpr_advskew > 0) {
2043 			if (carpr.carpr_advskew >= 255) {
2044 				error = EINVAL;
2045 				break;
2046 			}
2047 			if (carpr.carpr_advbase > 255) {
2048 				error = EINVAL;
2049 				break;
2050 			}
2051 			sc->sc_advbase = carpr.carpr_advbase;
2052 			sc->sc_advskew = carpr.carpr_advskew;
2053 			error--;
2054 		}
2055 		bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
2056 		if (error > 0)
2057 			error = EINVAL;
2058 		else {
2059 			error = 0;
2060 			carp_setrun(sc, 0);
2061 		}
2062 		break;
2063 
2064 	case SIOCGVH:
2065 		/* XXX: lockless read */
2066 		bzero(&carpr, sizeof(carpr));
2067 		carpr.carpr_state = sc->sc_state;
2068 		carpr.carpr_vhid = sc->sc_vhid;
2069 		carpr.carpr_advbase = sc->sc_advbase;
2070 		carpr.carpr_advskew = sc->sc_advskew;
2071 		error = priv_check(curthread, PRIV_NETINET_CARP);
2072 		if (error == 0)
2073 			bcopy(sc->sc_key, carpr.carpr_key,
2074 			    sizeof(carpr.carpr_key));
2075 		error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
2076 		break;
2077 
2078 	default:
2079 		error = EINVAL;
2080 	}
2081 
2082 	if (locked)
2083 		CARP_SCUNLOCK(sc);
2084 
2085 	carp_hmac_prepare(sc);
2086 
2087 	return (error);
2088 }
2089 
2090 /*
2091  * XXX: this is looutput. We should eventually use it from there.
2092  */
2093 static int
2094 carp_looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
2095     struct route *ro)
2096 {
2097 	u_int32_t af;
2098 	struct rtentry *rt = NULL;
2099 
2100 	M_ASSERTPKTHDR(m); /* check if we have the packet header */
2101 
2102 	if (ro != NULL)
2103 		rt = ro->ro_rt;
2104 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
2105 		m_freem(m);
2106 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
2107 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
2108 	}
2109 
2110 	ifp->if_opackets++;
2111 	ifp->if_obytes += m->m_pkthdr.len;
2112 
2113 	/* BPF writes need to be handled specially. */
2114 	if (dst->sa_family == AF_UNSPEC) {
2115 		bcopy(dst->sa_data, &af, sizeof(af));
2116 		dst->sa_family = af;
2117 	}
2118 
2119 #if 1	/* XXX */
2120 	switch (dst->sa_family) {
2121 	case AF_INET:
2122 	case AF_INET6:
2123 	case AF_IPX:
2124 	case AF_APPLETALK:
2125 		break;
2126 	default:
2127 		printf("carp_looutput: af=%d unexpected\n", dst->sa_family);
2128 		m_freem(m);
2129 		return (EAFNOSUPPORT);
2130 	}
2131 #endif
2132 	return(if_simloop(ifp, m, dst->sa_family, 0));
2133 }
2134 
2135 /*
2136  * Start output on carp interface. This function should never be called.
2137  */
2138 static void
2139 carp_start(struct ifnet *ifp)
2140 {
2141 #ifdef DEBUG
2142 	printf("%s: start called\n", ifp->if_xname);
2143 #endif
2144 }
2145 
2146 int
2147 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
2148     struct rtentry *rt)
2149 {
2150 	struct m_tag *mtag;
2151 	struct carp_softc *sc;
2152 	struct ifnet *carp_ifp;
2153 
2154 	if (!sa)
2155 		return (0);
2156 
2157 	switch (sa->sa_family) {
2158 #ifdef INET
2159 	case AF_INET:
2160 		break;
2161 #endif /* INET */
2162 #ifdef INET6
2163 	case AF_INET6:
2164 		break;
2165 #endif /* INET6 */
2166 	default:
2167 		return (0);
2168 	}
2169 
2170 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
2171 	if (mtag == NULL)
2172 		return (0);
2173 
2174 	bcopy(mtag + 1, &carp_ifp, sizeof(struct ifnet *));
2175 	sc = carp_ifp->if_softc;
2176 
2177 	/* Set the source MAC address to Virtual Router MAC Address */
2178 	switch (ifp->if_type) {
2179 	case IFT_ETHER:
2180 	case IFT_L2VLAN: {
2181 			struct ether_header *eh;
2182 
2183 			eh = mtod(m, struct ether_header *);
2184 			eh->ether_shost[0] = 0;
2185 			eh->ether_shost[1] = 0;
2186 			eh->ether_shost[2] = 0x5e;
2187 			eh->ether_shost[3] = 0;
2188 			eh->ether_shost[4] = 1;
2189 			eh->ether_shost[5] = sc->sc_vhid;
2190 		}
2191 		break;
2192 	case IFT_FDDI: {
2193 			struct fddi_header *fh;
2194 
2195 			fh = mtod(m, struct fddi_header *);
2196 			fh->fddi_shost[0] = 0;
2197 			fh->fddi_shost[1] = 0;
2198 			fh->fddi_shost[2] = 0x5e;
2199 			fh->fddi_shost[3] = 0;
2200 			fh->fddi_shost[4] = 1;
2201 			fh->fddi_shost[5] = sc->sc_vhid;
2202 		}
2203 		break;
2204 	case IFT_ISO88025: {
2205  			struct iso88025_header *th;
2206  			th = mtod(m, struct iso88025_header *);
2207 			th->iso88025_shost[0] = 3;
2208 			th->iso88025_shost[1] = 0;
2209 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
2210 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
2211 			th->iso88025_shost[4] = 0;
2212 			th->iso88025_shost[5] = 0;
2213 		}
2214 		break;
2215 	default:
2216 		printf("%s: carp is not supported for this interface type\n",
2217 		    ifp->if_xname);
2218 		return (EOPNOTSUPP);
2219 	}
2220 
2221 	return (0);
2222 }
2223 
2224 static void
2225 carp_set_state(struct carp_softc *sc, int state)
2226 {
2227 	int link_state;
2228 
2229 	if (sc->sc_carpdev)
2230 		CARP_SCLOCK_ASSERT(sc);
2231 
2232 	if (sc->sc_state == state)
2233 		return;
2234 
2235 	sc->sc_state = state;
2236 	switch (state) {
2237 	case BACKUP:
2238 		link_state = LINK_STATE_DOWN;
2239 		break;
2240 	case MASTER:
2241 		link_state = LINK_STATE_UP;
2242 		break;
2243 	default:
2244 		link_state = LINK_STATE_UNKNOWN;
2245 		break;
2246 	}
2247 	if_link_state_change(SC2IFP(sc), link_state);
2248 }
2249 
2250 void
2251 carp_carpdev_state(struct ifnet *ifp)
2252 {
2253 	struct carp_if *cif;
2254 
2255 	cif = ifp->if_carp;
2256 	CARP_LOCK(cif);
2257 	carp_carpdev_state_locked(cif);
2258 	CARP_UNLOCK(cif);
2259 }
2260 
2261 static void
2262 carp_carpdev_state_locked(struct carp_if *cif)
2263 {
2264 	struct carp_softc *sc;
2265 
2266 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list)
2267 		carp_sc_state_locked(sc);
2268 }
2269 
2270 static void
2271 carp_sc_state_locked(struct carp_softc *sc)
2272 {
2273 	CARP_SCLOCK_ASSERT(sc);
2274 
2275 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2276 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
2277 		sc->sc_flags_backup = SC2IFP(sc)->if_flags;
2278 		SC2IFP(sc)->if_flags &= ~IFF_UP;
2279 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
2280 		callout_stop(&sc->sc_ad_tmo);
2281 		callout_stop(&sc->sc_md_tmo);
2282 		callout_stop(&sc->sc_md6_tmo);
2283 		carp_set_state(sc, INIT);
2284 		carp_setrun(sc, 0);
2285 		if (!sc->sc_suppress) {
2286 			carp_suppress_preempt++;
2287 			if (carp_suppress_preempt == 1) {
2288 				CARP_SCUNLOCK(sc);
2289 				carp_send_ad_all();
2290 				CARP_SCLOCK(sc);
2291 			}
2292 		}
2293 		sc->sc_suppress = 1;
2294 	} else {
2295 		SC2IFP(sc)->if_flags |= sc->sc_flags_backup;
2296 		carp_set_state(sc, INIT);
2297 		carp_setrun(sc, 0);
2298 		if (sc->sc_suppress)
2299 			carp_suppress_preempt--;
2300 		sc->sc_suppress = 0;
2301 	}
2302 
2303 	return;
2304 }
2305 
2306 #ifdef INET
2307 extern  struct domain inetdomain;
2308 static struct protosw in_carp_protosw = {
2309 	.pr_type =		SOCK_RAW,
2310 	.pr_domain =		&inetdomain,
2311 	.pr_protocol =		IPPROTO_CARP,
2312 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2313 	.pr_input =		carp_input,
2314 	.pr_output =		(pr_output_t *)rip_output,
2315 	.pr_ctloutput =		rip_ctloutput,
2316 	.pr_usrreqs =		&rip_usrreqs
2317 };
2318 #endif
2319 
2320 #ifdef INET6
2321 extern	struct domain inet6domain;
2322 static struct ip6protosw in6_carp_protosw = {
2323 	.pr_type =		SOCK_RAW,
2324 	.pr_domain =		&inet6domain,
2325 	.pr_protocol =		IPPROTO_CARP,
2326 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2327 	.pr_input =		carp6_input,
2328 	.pr_output =		rip6_output,
2329 	.pr_ctloutput =		rip6_ctloutput,
2330 	.pr_usrreqs =		&rip6_usrreqs
2331 };
2332 #endif
2333 
2334 static void
2335 carp_mod_cleanup(void)
2336 {
2337 
2338 	if (if_detach_event_tag == NULL)
2339 		return;
2340 	EVENTHANDLER_DEREGISTER(ifnet_departure_event, if_detach_event_tag);
2341 	if_clone_detach(&carp_cloner);
2342 #ifdef INET
2343 	if (proto_reg[CARP_INET] == 0) {
2344 		(void)ipproto_unregister(IPPROTO_CARP);
2345 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2346 		proto_reg[CARP_INET] = -1;
2347 	}
2348 	carp_iamatch_p = NULL;
2349 #endif
2350 #ifdef INET6
2351 	if (proto_reg[CARP_INET6] == 0) {
2352 		(void)ip6proto_unregister(IPPROTO_CARP);
2353 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2354 		proto_reg[CARP_INET6] = -1;
2355 	}
2356 	carp_iamatch6_p = NULL;
2357 	carp_macmatch6_p = NULL;
2358 #endif
2359 	carp_linkstate_p = NULL;
2360 	carp_forus_p = NULL;
2361 	carp_output_p = NULL;
2362 	mtx_destroy(&carp_mtx);
2363 }
2364 
2365 static int
2366 carp_mod_load(void)
2367 {
2368 	int err;
2369 
2370 	if_detach_event_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
2371 		carp_ifdetach, NULL, EVENTHANDLER_PRI_ANY);
2372 	if (if_detach_event_tag == NULL)
2373 		return (ENOMEM);
2374 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2375 	LIST_INIT(&carpif_list);
2376 	if_clone_attach(&carp_cloner);
2377 	carp_linkstate_p = carp_carpdev_state;
2378 	carp_forus_p = carp_forus;
2379 	carp_output_p = carp_output;
2380 #ifdef INET6
2381 	carp_iamatch6_p = carp_iamatch6;
2382 	carp_macmatch6_p = carp_macmatch6;
2383 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2384 	    (struct protosw *)&in6_carp_protosw);
2385 	if (proto_reg[CARP_INET6] != 0) {
2386 		printf("carp: error %d attaching to PF_INET6\n",
2387 		    proto_reg[CARP_INET6]);
2388 		carp_mod_cleanup();
2389 		return (proto_reg[CARP_INET6]);
2390 	}
2391 	err = ip6proto_register(IPPROTO_CARP);
2392 	if (err) {
2393 		printf("carp: error %d registering with INET6\n", err);
2394 		carp_mod_cleanup();
2395 		return (err);
2396 	}
2397 #endif
2398 #ifdef INET
2399 	carp_iamatch_p = carp_iamatch;
2400 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2401 	if (proto_reg[CARP_INET] != 0) {
2402 		printf("carp: error %d attaching to PF_INET\n",
2403 		    proto_reg[CARP_INET]);
2404 		carp_mod_cleanup();
2405 		return (proto_reg[CARP_INET]);
2406 	}
2407 	err = ipproto_register(IPPROTO_CARP);
2408 	if (err) {
2409 		printf("carp: error %d registering with INET\n", err);
2410 		carp_mod_cleanup();
2411 		return (err);
2412 	}
2413 #endif
2414 	return 0;
2415 }
2416 
2417 static int
2418 carp_modevent(module_t mod, int type, void *data)
2419 {
2420 	switch (type) {
2421 	case MOD_LOAD:
2422 		return carp_mod_load();
2423 		/* NOTREACHED */
2424 	case MOD_UNLOAD:
2425 		/*
2426 		 * XXX: For now, disallow module unloading by default due to
2427 		 * a race condition where a thread may dereference one of the
2428 		 * function pointer hooks after the module has been
2429 		 * unloaded, during processing of a packet, causing a panic.
2430 		 */
2431 #ifdef CARPMOD_CAN_UNLOAD
2432 		carp_mod_cleanup();
2433 #else
2434 		return (EBUSY);
2435 #endif
2436 		break;
2437 
2438 	default:
2439 		return (EINVAL);
2440 	}
2441 
2442 	return (0);
2443 }
2444 
2445 static moduledata_t carp_mod = {
2446 	"carp",
2447 	carp_modevent,
2448 	0
2449 };
2450 
2451 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2452