xref: /freebsd/sys/netinet/ip_carp.c (revision 8be96e101f2691b80ff9562b72f874da82e735aa)
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 #ifdef INET
70 #include <netinet/in.h>
71 #include <netinet/in_var.h>
72 #include <netinet/in_systm.h>
73 #include <netinet/ip.h>
74 #include <netinet/ip_var.h>
75 #include <netinet/if_ether.h>
76 #include <machine/in_cksum.h>
77 #endif
78 
79 #ifdef INET6
80 #include <netinet/icmp6.h>
81 #include <netinet/ip6.h>
82 #include <netinet6/ip6protosw.h>
83 #include <netinet6/ip6_var.h>
84 #include <netinet6/scope6_var.h>
85 #include <netinet6/nd6.h>
86 #endif
87 
88 #include <crypto/sha1.h>
89 #include <netinet/ip_carp.h>
90 
91 #define	CARP_IFNAME	"carp"
92 static MALLOC_DEFINE(M_CARP, "CARP", "CARP interfaces");
93 SYSCTL_DECL(_net_inet_carp);
94 
95 struct carp_softc {
96 	struct ifnet	 	*sc_ifp;	/* Interface clue */
97 	struct ifnet		*sc_carpdev;	/* Pointer to parent interface */
98 	struct in_ifaddr 	*sc_ia;		/* primary iface address */
99 	struct ip_moptions 	 sc_imo;
100 #ifdef INET6
101 	struct in6_ifaddr 	*sc_ia6;	/* primary iface address v6 */
102 	struct ip6_moptions 	 sc_im6o;
103 #endif /* INET6 */
104 	TAILQ_ENTRY(carp_softc)	 sc_list;
105 
106 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
107 
108 	int			 sc_flags_backup;
109 	int			 sc_suppress;
110 
111 	int			 sc_sendad_errors;
112 #define	CARP_SENDAD_MAX_ERRORS	3
113 	int			 sc_sendad_success;
114 #define	CARP_SENDAD_MIN_SUCCESS 3
115 
116 	int			 sc_vhid;
117 	int			 sc_advskew;
118 	int			 sc_naddrs;
119 	int			 sc_naddrs6;
120 	int			 sc_advbase;	/* seconds */
121 	int			 sc_init_counter;
122 	u_int64_t		 sc_counter;
123 
124 	/* authentication */
125 #define CARP_HMAC_PAD	64
126 	unsigned char sc_key[CARP_KEY_LEN];
127 	unsigned char sc_pad[CARP_HMAC_PAD];
128 	SHA1_CTX sc_sha1;
129 
130 	struct callout		 sc_ad_tmo;	/* advertisement timeout */
131 	struct callout		 sc_md_tmo;	/* master down timeout */
132 	struct callout 		 sc_md6_tmo;	/* master down timeout */
133 
134 	LIST_ENTRY(carp_softc)	 sc_next;	/* Interface clue */
135 };
136 #define	SC2IFP(sc)	((sc)->sc_ifp)
137 
138 /* These are external networking stack hooks for CARP */
139 /* net/if.c */
140 extern void (*carp_linkstate_p)(struct ifnet *);
141 /* net/if_bridge.c net/if_ethersubr.c */
142 extern struct ifnet *(*carp_forus_p)(struct ifnet *, u_char *);
143 /* net/if_ethersubr.c */
144 extern int (*carp_output_p)(struct ifnet *, struct mbuf *,
145     struct sockaddr *, struct rtentry *);
146 #ifdef INET
147 /* netinet/if_ether.c */
148 extern int (*carp_iamatch_p)(struct ifnet *, struct in_ifaddr *,
149     struct in_addr *, u_int8_t **);
150 #endif
151 #ifdef INET6
152 /* netinet6/nd6_nbr.c */
153 extern struct ifaddr *(*carp_iamatch6_p)(struct ifnet *, struct in6_addr *);
154 extern caddr_t (*carp_macmatch6_p)(struct ifnet *, struct mbuf *,
155     const struct in6_addr *);
156 #endif
157 
158 int carp_suppress_preempt = 0;
159 int carp_opts[CARPCTL_MAXID] = { 0, 1, 0, 1, 0, 0 };	/* XXX for now */
160 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
161 SYSCTL_INT(_net_inet_carp, CARPCTL_ALLOW, allow, CTLFLAG_RW,
162     &carp_opts[CARPCTL_ALLOW], 0, "Accept incoming CARP packets");
163 SYSCTL_INT(_net_inet_carp, CARPCTL_PREEMPT, preempt, CTLFLAG_RW,
164     &carp_opts[CARPCTL_PREEMPT], 0, "high-priority backup preemption mode");
165 SYSCTL_INT(_net_inet_carp, CARPCTL_LOG, log, CTLFLAG_RW,
166     &carp_opts[CARPCTL_LOG], 0, "log bad carp packets");
167 SYSCTL_INT(_net_inet_carp, CARPCTL_ARPBALANCE, arpbalance, CTLFLAG_RW,
168     &carp_opts[CARPCTL_ARPBALANCE], 0, "balance arp responses");
169 SYSCTL_INT(_net_inet_carp, OID_AUTO, suppress_preempt, CTLFLAG_RD,
170     &carp_suppress_preempt, 0, "Preemption is suppressed");
171 
172 struct carpstats carpstats;
173 SYSCTL_STRUCT(_net_inet_carp, CARPCTL_STATS, stats, CTLFLAG_RW,
174     &carpstats, carpstats,
175     "CARP statistics (struct carpstats, netinet/ip_carp.h)");
176 
177 struct carp_if {
178 	TAILQ_HEAD(, carp_softc) vhif_vrs;
179 	int vhif_nvrs;
180 
181 	struct ifnet 	*vhif_ifp;
182 	struct mtx	 vhif_mtx;
183 };
184 
185 #define	CARP_INET	0
186 #define	CARP_INET6	1
187 static int proto_reg[] = {-1, -1};
188 
189 /* Get carp_if from softc. Valid after carp_set_addr{,6}. */
190 #define	SC2CIF(sc)		((struct carp_if *)(sc)->sc_carpdev->if_carp)
191 
192 /* lock per carp_if queue */
193 #define	CARP_LOCK_INIT(cif)	mtx_init(&(cif)->vhif_mtx, "carp_if", 	\
194 	NULL, MTX_DEF)
195 #define	CARP_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->vhif_mtx)
196 #define	CARP_LOCK_ASSERT(cif)	mtx_assert(&(cif)->vhif_mtx, MA_OWNED)
197 #define	CARP_LOCK(cif)		mtx_lock(&(cif)->vhif_mtx)
198 #define	CARP_UNLOCK(cif)	mtx_unlock(&(cif)->vhif_mtx)
199 
200 #define	CARP_SCLOCK(sc)		mtx_lock(&SC2CIF(sc)->vhif_mtx)
201 #define	CARP_SCUNLOCK(sc)	mtx_unlock(&SC2CIF(sc)->vhif_mtx)
202 #define	CARP_SCLOCK_ASSERT(sc)	mtx_assert(&SC2CIF(sc)->vhif_mtx, MA_OWNED)
203 
204 #define	CARP_LOG(...)	do {				\
205 	if (carp_opts[CARPCTL_LOG] > 0)			\
206 		log(LOG_INFO, __VA_ARGS__);		\
207 } while (0)
208 
209 #define	CARP_DEBUG(...)	do {				\
210 	if (carp_opts[CARPCTL_LOG] > 1)			\
211 		log(LOG_DEBUG, __VA_ARGS__);		\
212 } while (0)
213 
214 static void	carp_hmac_prepare(struct carp_softc *);
215 static void	carp_hmac_generate(struct carp_softc *, u_int32_t *,
216 		    unsigned char *);
217 static int	carp_hmac_verify(struct carp_softc *, u_int32_t *,
218 		    unsigned char *);
219 static void	carp_setroute(struct carp_softc *, int);
220 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
221 static int 	carp_clone_create(struct if_clone *, int, caddr_t);
222 static void 	carp_clone_destroy(struct ifnet *);
223 static void	carpdetach(struct carp_softc *, int);
224 static int	carp_prepare_ad(struct mbuf *, struct carp_softc *,
225 		    struct carp_header *);
226 static void	carp_send_ad_all(void);
227 static void	carp_send_ad(void *);
228 static void	carp_send_ad_locked(struct carp_softc *);
229 static void	carp_send_arp(struct carp_softc *);
230 static void	carp_master_down(void *);
231 static void	carp_master_down_locked(struct carp_softc *);
232 static int	carp_ioctl(struct ifnet *, u_long, caddr_t);
233 static int	carp_looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
234     		    struct route *);
235 static void	carp_start(struct ifnet *);
236 static void	carp_setrun(struct carp_softc *, sa_family_t);
237 static void	carp_set_state(struct carp_softc *, int);
238 static int	carp_addrcount(struct carp_if *, struct in_ifaddr *, int);
239 enum	{ CARP_COUNT_MASTER, CARP_COUNT_RUNNING };
240 
241 static void	carp_multicast_cleanup(struct carp_softc *);
242 static int	carp_set_addr(struct carp_softc *, struct sockaddr_in *);
243 static int	carp_del_addr(struct carp_softc *, struct sockaddr_in *);
244 static void	carp_carpdev_state_locked(struct carp_if *);
245 static void	carp_sc_state_locked(struct carp_softc *);
246 #ifdef INET6
247 static void	carp_send_na(struct carp_softc *);
248 static int	carp_set_addr6(struct carp_softc *, struct sockaddr_in6 *);
249 static int	carp_del_addr6(struct carp_softc *, struct sockaddr_in6 *);
250 static void	carp_multicast6_cleanup(struct carp_softc *);
251 #endif
252 
253 static LIST_HEAD(, carp_softc) carpif_list;
254 static struct mtx carp_mtx;
255 IFC_SIMPLE_DECLARE(carp, 0);
256 
257 static eventhandler_tag if_detach_event_tag;
258 
259 static __inline u_int16_t
260 carp_cksum(struct mbuf *m, int len)
261 {
262 	return (in_cksum(m, len));
263 }
264 
265 static void
266 carp_hmac_prepare(struct carp_softc *sc)
267 {
268 	u_int8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
269 	u_int8_t vhid = sc->sc_vhid & 0xff;
270 	struct ifaddr *ifa;
271 	int i, found;
272 #ifdef INET
273 	struct in_addr last, cur, in;
274 #endif
275 #ifdef INET6
276 	struct in6_addr last6, cur6, in6;
277 #endif
278 
279 	if (sc->sc_carpdev)
280 		CARP_SCLOCK(sc);
281 
282 	/* XXX: possible race here */
283 
284 	/* compute ipad from key */
285 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
286 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
287 	for (i = 0; i < sizeof(sc->sc_pad); i++)
288 		sc->sc_pad[i] ^= 0x36;
289 
290 	/* precompute first part of inner hash */
291 	SHA1Init(&sc->sc_sha1);
292 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
293 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
294 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
295 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
296 #ifdef INET
297 	cur.s_addr = 0;
298 	do {
299 		found = 0;
300 		last = cur;
301 		cur.s_addr = 0xffffffff;
302 		IF_ADDR_LOCK(SC2IFP(sc));
303 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
304 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
305 			if (ifa->ifa_addr->sa_family == AF_INET &&
306 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
307 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
308 				cur.s_addr = in.s_addr;
309 				found++;
310 			}
311 		}
312 		IF_ADDR_UNLOCK(SC2IFP(sc));
313 		if (found)
314 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
315 	} while (found);
316 #endif /* INET */
317 #ifdef INET6
318 	memset(&cur6, 0, sizeof(cur6));
319 	do {
320 		found = 0;
321 		last6 = cur6;
322 		memset(&cur6, 0xff, sizeof(cur6));
323 		IF_ADDR_LOCK(SC2IFP(sc));
324 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
325 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
326 			if (IN6_IS_SCOPE_EMBED(&in6))
327 				in6.s6_addr16[1] = 0;
328 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
329 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
330 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
331 				cur6 = in6;
332 				found++;
333 			}
334 		}
335 		IF_ADDR_UNLOCK(SC2IFP(sc));
336 		if (found)
337 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
338 	} while (found);
339 #endif /* INET6 */
340 
341 	/* convert ipad to opad */
342 	for (i = 0; i < sizeof(sc->sc_pad); i++)
343 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
344 
345 	if (sc->sc_carpdev)
346 		CARP_SCUNLOCK(sc);
347 }
348 
349 static void
350 carp_hmac_generate(struct carp_softc *sc, u_int32_t counter[2],
351     unsigned char md[20])
352 {
353 	SHA1_CTX sha1ctx;
354 
355 	/* fetch first half of inner hash */
356 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
357 
358 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
359 	SHA1Final(md, &sha1ctx);
360 
361 	/* outer hash */
362 	SHA1Init(&sha1ctx);
363 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
364 	SHA1Update(&sha1ctx, md, 20);
365 	SHA1Final(md, &sha1ctx);
366 }
367 
368 static int
369 carp_hmac_verify(struct carp_softc *sc, u_int32_t counter[2],
370     unsigned char md[20])
371 {
372 	unsigned char md2[20];
373 
374 	CARP_SCLOCK_ASSERT(sc);
375 
376 	carp_hmac_generate(sc, counter, md2);
377 
378 	return (bcmp(md, md2, sizeof(md2)));
379 }
380 
381 static void
382 carp_setroute(struct carp_softc *sc, int cmd)
383 {
384 	struct ifaddr *ifa;
385 	int s;
386 
387 	if (sc->sc_carpdev)
388 		CARP_SCLOCK_ASSERT(sc);
389 
390 	s = splnet();
391 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
392 		if (ifa->ifa_addr->sa_family == AF_INET &&
393 		    sc->sc_carpdev != NULL) {
394 			int count = carp_addrcount(
395 			    (struct carp_if *)sc->sc_carpdev->if_carp,
396 			    ifatoia(ifa), CARP_COUNT_MASTER);
397 
398 			if ((cmd == RTM_ADD && count == 1) ||
399 			    (cmd == RTM_DELETE && count == 0))
400 				rtinit(ifa, cmd, RTF_UP | RTF_HOST);
401 		}
402 	}
403 	splx(s);
404 }
405 
406 static int
407 carp_clone_create(struct if_clone *ifc, int unit, caddr_t params)
408 {
409 
410 	struct carp_softc *sc;
411 	struct ifnet *ifp;
412 
413 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
414 	ifp = SC2IFP(sc) = if_alloc(IFT_ETHER);
415 	if (ifp == NULL) {
416 		free(sc, M_CARP);
417 		return (ENOSPC);
418 	}
419 
420 	sc->sc_flags_backup = 0;
421 	sc->sc_suppress = 0;
422 	sc->sc_advbase = CARP_DFLTINTV;
423 	sc->sc_vhid = -1;	/* required setting */
424 	sc->sc_advskew = 0;
425 	sc->sc_init_counter = 1;
426 	sc->sc_naddrs = sc->sc_naddrs6 = 0; /* M_ZERO? */
427 	sc->sc_imo.imo_membership = (struct in_multi **)malloc(
428 	    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
429 	    M_WAITOK);
430 	sc->sc_imo.imo_mfilters = NULL;
431 	sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
432 	sc->sc_imo.imo_multicast_vif = -1;
433 #ifdef INET6
434 	sc->sc_im6o.im6o_membership = (struct in6_multi **)malloc(
435 	    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
436 	    M_WAITOK);
437 	sc->sc_im6o.im6o_mfilters = NULL;
438 	sc->sc_im6o.im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
439 	sc->sc_im6o.im6o_multicast_hlim = CARP_DFLTTL;
440 #endif
441 
442 	callout_init(&sc->sc_ad_tmo, CALLOUT_MPSAFE);
443 	callout_init(&sc->sc_md_tmo, CALLOUT_MPSAFE);
444 	callout_init(&sc->sc_md6_tmo, CALLOUT_MPSAFE);
445 
446 	ifp->if_softc = sc;
447 	if_initname(ifp, CARP_IFNAME, unit);
448 	ifp->if_mtu = ETHERMTU;
449 	ifp->if_flags = IFF_LOOPBACK;
450 	ifp->if_ioctl = carp_ioctl;
451 	ifp->if_output = carp_looutput;
452 	ifp->if_start = carp_start;
453 	ifp->if_type = IFT_CARP;
454 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
455 	ifp->if_hdrlen = 0;
456 	if_attach(ifp);
457 	bpfattach(SC2IFP(sc), DLT_NULL, sizeof(u_int32_t));
458 	mtx_lock(&carp_mtx);
459 	LIST_INSERT_HEAD(&carpif_list, sc, sc_next);
460 	mtx_unlock(&carp_mtx);
461 	return (0);
462 }
463 
464 static void
465 carp_clone_destroy(struct ifnet *ifp)
466 {
467 	struct carp_softc *sc = ifp->if_softc;
468 
469 	if (sc->sc_carpdev)
470 		CARP_SCLOCK(sc);
471 	carpdetach(sc, 1);	/* Returns unlocked. */
472 
473 	mtx_lock(&carp_mtx);
474 	LIST_REMOVE(sc, sc_next);
475 	mtx_unlock(&carp_mtx);
476 	bpfdetach(ifp);
477 	if_detach(ifp);
478 	if_free_type(ifp, IFT_ETHER);
479 	free(sc->sc_imo.imo_membership, M_CARP);
480 #ifdef INET6
481 	free(sc->sc_im6o.im6o_membership, M_CARP);
482 #endif
483 	free(sc, M_CARP);
484 }
485 
486 /*
487  * This function can be called on CARP interface destroy path,
488  * and in case of the removal of the underlying interface as
489  * well. We differentiate these two cases. In the latter case
490  * we do not cleanup our multicast memberships, since they
491  * are already freed. Also, in the latter case we do not
492  * release the lock on return, because the function will be
493  * called once more, for another CARP instance on the same
494  * interface.
495  */
496 static void
497 carpdetach(struct carp_softc *sc, int unlock)
498 {
499 	struct carp_if *cif;
500 
501 	callout_stop(&sc->sc_ad_tmo);
502 	callout_stop(&sc->sc_md_tmo);
503 	callout_stop(&sc->sc_md6_tmo);
504 
505 	if (sc->sc_suppress)
506 		carp_suppress_preempt--;
507 	sc->sc_suppress = 0;
508 
509 	if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS)
510 		carp_suppress_preempt--;
511 	sc->sc_sendad_errors = 0;
512 
513 	carp_set_state(sc, INIT);
514 	SC2IFP(sc)->if_flags &= ~IFF_UP;
515 	carp_setrun(sc, 0);
516 	if (unlock)
517 		carp_multicast_cleanup(sc);
518 #ifdef INET6
519 	carp_multicast6_cleanup(sc);
520 #endif
521 
522 	if (sc->sc_carpdev != NULL) {
523 		cif = (struct carp_if *)sc->sc_carpdev->if_carp;
524 		CARP_LOCK_ASSERT(cif);
525 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
526 		if (!--cif->vhif_nvrs) {
527 			ifpromisc(sc->sc_carpdev, 0);
528 			sc->sc_carpdev->if_carp = NULL;
529 			CARP_LOCK_DESTROY(cif);
530 			free(cif, M_CARP);
531 		} else if (unlock)
532 			CARP_UNLOCK(cif);
533 		sc->sc_carpdev = NULL;
534 	}
535 }
536 
537 /* Detach an interface from the carp. */
538 static void
539 carp_ifdetach(void *arg __unused, struct ifnet *ifp)
540 {
541 	struct carp_if *cif = (struct carp_if *)ifp->if_carp;
542 	struct carp_softc *sc, *nextsc;
543 
544 	if (cif == NULL)
545 		return;
546 
547 	/*
548 	 * XXX: At the end of for() cycle the lock will be destroyed.
549 	 */
550 	CARP_LOCK(cif);
551 	for (sc = TAILQ_FIRST(&cif->vhif_vrs); sc; sc = nextsc) {
552 		nextsc = TAILQ_NEXT(sc, sc_list);
553 		carpdetach(sc, 0);
554 	}
555 }
556 
557 /*
558  * process input packet.
559  * we have rearranged checks order compared to the rfc,
560  * but it seems more efficient this way or not possible otherwise.
561  */
562 void
563 carp_input(struct mbuf *m, int hlen)
564 {
565 	struct ip *ip = mtod(m, struct ip *);
566 	struct carp_header *ch;
567 	int iplen, len;
568 
569 	CARPSTATS_INC(carps_ipackets);
570 
571 	if (!carp_opts[CARPCTL_ALLOW]) {
572 		m_freem(m);
573 		return;
574 	}
575 
576 	/* check if received on a valid carp interface */
577 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
578 		CARPSTATS_INC(carps_badif);
579 		CARP_DEBUG("carp_input: packet received on non-carp "
580 		    "interface: %s\n",
581 		    m->m_pkthdr.rcvif->if_xname);
582 		m_freem(m);
583 		return;
584 	}
585 
586 	/* verify that the IP TTL is 255.  */
587 	if (ip->ip_ttl != CARP_DFLTTL) {
588 		CARPSTATS_INC(carps_badttl);
589 		CARP_DEBUG("carp_input: received ttl %d != 255 on %s\n",
590 		    ip->ip_ttl,
591 		    m->m_pkthdr.rcvif->if_xname);
592 		m_freem(m);
593 		return;
594 	}
595 
596 	iplen = ip->ip_hl << 2;
597 
598 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
599 		CARPSTATS_INC(carps_badlen);
600 		CARP_DEBUG("carp_input: received len %zd < "
601 		    "sizeof(struct carp_header) on %s\n",
602 		    m->m_len - sizeof(struct ip),
603 		    m->m_pkthdr.rcvif->if_xname);
604 		m_freem(m);
605 		return;
606 	}
607 
608 	if (iplen + sizeof(*ch) < m->m_len) {
609 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
610 			CARPSTATS_INC(carps_hdrops);
611 			CARP_DEBUG("carp_input: pullup failed\n");
612 			return;
613 		}
614 		ip = mtod(m, struct ip *);
615 	}
616 	ch = (struct carp_header *)((char *)ip + iplen);
617 
618 	/*
619 	 * verify that the received packet length is
620 	 * equal to the CARP header
621 	 */
622 	len = iplen + sizeof(*ch);
623 	if (len > m->m_pkthdr.len) {
624 		CARPSTATS_INC(carps_badlen);
625 		CARP_DEBUG("carp_input: packet too short %d on %s\n",
626 		    m->m_pkthdr.len,
627 		    m->m_pkthdr.rcvif->if_xname);
628 		m_freem(m);
629 		return;
630 	}
631 
632 	if ((m = m_pullup(m, len)) == NULL) {
633 		CARPSTATS_INC(carps_hdrops);
634 		return;
635 	}
636 	ip = mtod(m, struct ip *);
637 	ch = (struct carp_header *)((char *)ip + iplen);
638 
639 	/* verify the CARP checksum */
640 	m->m_data += iplen;
641 	if (carp_cksum(m, len - iplen)) {
642 		CARPSTATS_INC(carps_badsum);
643 		CARP_DEBUG("carp_input: checksum failed on %s\n",
644 		    m->m_pkthdr.rcvif->if_xname);
645 		m_freem(m);
646 		return;
647 	}
648 	m->m_data -= iplen;
649 
650 	carp_input_c(m, ch, AF_INET);
651 }
652 
653 #ifdef INET6
654 int
655 carp6_input(struct mbuf **mp, int *offp, int proto)
656 {
657 	struct mbuf *m = *mp;
658 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
659 	struct carp_header *ch;
660 	u_int len;
661 
662 	CARPSTATS_INC(carps_ipackets6);
663 
664 	if (!carp_opts[CARPCTL_ALLOW]) {
665 		m_freem(m);
666 		return (IPPROTO_DONE);
667 	}
668 
669 	/* check if received on a valid carp interface */
670 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
671 		CARPSTATS_INC(carps_badif);
672 		CARP_DEBUG("carp6_input: packet received on non-carp "
673 		    "interface: %s\n",
674 		    m->m_pkthdr.rcvif->if_xname);
675 		m_freem(m);
676 		return (IPPROTO_DONE);
677 	}
678 
679 	/* verify that the IP TTL is 255 */
680 	if (ip6->ip6_hlim != CARP_DFLTTL) {
681 		CARPSTATS_INC(carps_badttl);
682 		CARP_DEBUG("carp6_input: received ttl %d != 255 on %s\n",
683 		    ip6->ip6_hlim,
684 		    m->m_pkthdr.rcvif->if_xname);
685 		m_freem(m);
686 		return (IPPROTO_DONE);
687 	}
688 
689 	/* verify that we have a complete carp packet */
690 	len = m->m_len;
691 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
692 	if (ch == NULL) {
693 		CARPSTATS_INC(carps_badlen);
694 		CARP_DEBUG("carp6_input: packet size %u too small\n", len);
695 		return (IPPROTO_DONE);
696 	}
697 
698 
699 	/* verify the CARP checksum */
700 	m->m_data += *offp;
701 	if (carp_cksum(m, sizeof(*ch))) {
702 		CARPSTATS_INC(carps_badsum);
703 		CARP_DEBUG("carp6_input: checksum failed, on %s\n",
704 		    m->m_pkthdr.rcvif->if_xname);
705 		m_freem(m);
706 		return (IPPROTO_DONE);
707 	}
708 	m->m_data -= *offp;
709 
710 	carp_input_c(m, ch, AF_INET6);
711 	return (IPPROTO_DONE);
712 }
713 #endif /* INET6 */
714 
715 static void
716 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
717 {
718 	struct ifnet *ifp = m->m_pkthdr.rcvif;
719 	struct carp_softc *sc;
720 	u_int64_t tmp_counter;
721 	struct timeval sc_tv, ch_tv;
722 
723 	/* verify that the VHID is valid on the receiving interface */
724 	CARP_LOCK(ifp->if_carp);
725 	TAILQ_FOREACH(sc, &((struct carp_if *)ifp->if_carp)->vhif_vrs, sc_list)
726 		if (sc->sc_vhid == ch->carp_vhid)
727 			break;
728 
729 	if (!sc || !((SC2IFP(sc)->if_flags & IFF_UP) &&
730 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
731 		CARPSTATS_INC(carps_badvhid);
732 		CARP_UNLOCK(ifp->if_carp);
733 		m_freem(m);
734 		return;
735 	}
736 
737 	getmicrotime(&SC2IFP(sc)->if_lastchange);
738 	SC2IFP(sc)->if_ipackets++;
739 	SC2IFP(sc)->if_ibytes += m->m_pkthdr.len;
740 
741 	if (bpf_peers_present(SC2IFP(sc)->if_bpf)) {
742 		struct ip *ip = mtod(m, struct ip *);
743 		uint32_t af1 = af;
744 
745 		/* BPF wants net byte order */
746 		ip->ip_len = htons(ip->ip_len + (ip->ip_hl << 2));
747 		ip->ip_off = htons(ip->ip_off);
748 		bpf_mtap2(SC2IFP(sc)->if_bpf, &af1, sizeof(af1), m);
749 	}
750 
751 	/* verify the CARP version. */
752 	if (ch->carp_version != CARP_VERSION) {
753 		CARPSTATS_INC(carps_badver);
754 		SC2IFP(sc)->if_ierrors++;
755 		CARP_UNLOCK(ifp->if_carp);
756 		CARP_DEBUG("%s; invalid version %d\n",
757 		    SC2IFP(sc)->if_xname,
758 		    ch->carp_version);
759 		m_freem(m);
760 		return;
761 	}
762 
763 	/* verify the hash */
764 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
765 		CARPSTATS_INC(carps_badauth);
766 		SC2IFP(sc)->if_ierrors++;
767 		CARP_UNLOCK(ifp->if_carp);
768 		CARP_DEBUG("%s: incorrect hash\n", SC2IFP(sc)->if_xname);
769 		m_freem(m);
770 		return;
771 	}
772 
773 	tmp_counter = ntohl(ch->carp_counter[0]);
774 	tmp_counter = tmp_counter<<32;
775 	tmp_counter += ntohl(ch->carp_counter[1]);
776 
777 	/* XXX Replay protection goes here */
778 
779 	sc->sc_init_counter = 0;
780 	sc->sc_counter = tmp_counter;
781 
782 	sc_tv.tv_sec = sc->sc_advbase;
783 	if (carp_suppress_preempt && sc->sc_advskew <  240)
784 		sc_tv.tv_usec = 240 * 1000000 / 256;
785 	else
786 		sc_tv.tv_usec = sc->sc_advskew * 1000000 / 256;
787 	ch_tv.tv_sec = ch->carp_advbase;
788 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
789 
790 	switch (sc->sc_state) {
791 	case INIT:
792 		break;
793 	case MASTER:
794 		/*
795 		 * If we receive an advertisement from a master who's going to
796 		 * be more frequent than us, go into BACKUP state.
797 		 */
798 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
799 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
800 			callout_stop(&sc->sc_ad_tmo);
801 			CARP_LOG("%s: MASTER -> BACKUP "
802 			   "(more frequent advertisement received)\n",
803 			   SC2IFP(sc)->if_xname);
804 			carp_set_state(sc, BACKUP);
805 			carp_setrun(sc, 0);
806 			carp_setroute(sc, RTM_DELETE);
807 		}
808 		break;
809 	case BACKUP:
810 		/*
811 		 * If we're pre-empting masters who advertise slower than us,
812 		 * and this one claims to be slower, treat him as down.
813 		 */
814 		if (carp_opts[CARPCTL_PREEMPT] &&
815 		    timevalcmp(&sc_tv, &ch_tv, <)) {
816 			CARP_LOG("%s: BACKUP -> MASTER "
817 			    "(preempting a slower master)\n",
818 			    SC2IFP(sc)->if_xname);
819 			carp_master_down_locked(sc);
820 			break;
821 		}
822 
823 		/*
824 		 *  If the master is going to advertise at such a low frequency
825 		 *  that he's guaranteed to time out, we'd might as well just
826 		 *  treat him as timed out now.
827 		 */
828 		sc_tv.tv_sec = sc->sc_advbase * 3;
829 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
830 			CARP_LOG("%s: BACKUP -> MASTER "
831 			    "(master timed out)\n",
832 			    SC2IFP(sc)->if_xname);
833 			carp_master_down_locked(sc);
834 			break;
835 		}
836 
837 		/*
838 		 * Otherwise, we reset the counter and wait for the next
839 		 * advertisement.
840 		 */
841 		carp_setrun(sc, af);
842 		break;
843 	}
844 
845 	CARP_UNLOCK(ifp->if_carp);
846 
847 	m_freem(m);
848 	return;
849 }
850 
851 static int
852 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
853 {
854 	struct m_tag *mtag;
855 	struct ifnet *ifp = SC2IFP(sc);
856 
857 	if (sc->sc_init_counter) {
858 		/* this could also be seconds since unix epoch */
859 		sc->sc_counter = arc4random();
860 		sc->sc_counter = sc->sc_counter << 32;
861 		sc->sc_counter += arc4random();
862 	} else
863 		sc->sc_counter++;
864 
865 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
866 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
867 
868 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
869 
870 	/* Tag packet for carp_output */
871 	mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct ifnet *), M_NOWAIT);
872 	if (mtag == NULL) {
873 		m_freem(m);
874 		SC2IFP(sc)->if_oerrors++;
875 		return (ENOMEM);
876 	}
877 	bcopy(&ifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *));
878 	m_tag_prepend(m, mtag);
879 
880 	return (0);
881 }
882 
883 static void
884 carp_send_ad_all(void)
885 {
886 	struct carp_softc *sc;
887 
888 	mtx_lock(&carp_mtx);
889 	LIST_FOREACH(sc, &carpif_list, sc_next) {
890 		if (sc->sc_carpdev == NULL)
891 			continue;
892 		CARP_SCLOCK(sc);
893 		if ((SC2IFP(sc)->if_flags & IFF_UP) &&
894 		    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING) &&
895 		     sc->sc_state == MASTER)
896 			carp_send_ad_locked(sc);
897 		CARP_SCUNLOCK(sc);
898 	}
899 	mtx_unlock(&carp_mtx);
900 }
901 
902 static void
903 carp_send_ad(void *v)
904 {
905 	struct carp_softc *sc = v;
906 
907 	CARP_SCLOCK(sc);
908 	carp_send_ad_locked(sc);
909 	CARP_SCUNLOCK(sc);
910 }
911 
912 static void
913 carp_send_ad_locked(struct carp_softc *sc)
914 {
915 	struct carp_header ch;
916 	struct timeval tv;
917 	struct carp_header *ch_ptr;
918 	struct mbuf *m;
919 	int len, advbase, advskew;
920 
921 	CARP_SCLOCK_ASSERT(sc);
922 
923 	/* bow out if we've lost our UPness or RUNNINGuiness */
924 	if (!((SC2IFP(sc)->if_flags & IFF_UP) &&
925 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
926 		advbase = 255;
927 		advskew = 255;
928 	} else {
929 		advbase = sc->sc_advbase;
930 		if (!carp_suppress_preempt || sc->sc_advskew > 240)
931 			advskew = sc->sc_advskew;
932 		else
933 			advskew = 240;
934 		tv.tv_sec = advbase;
935 		tv.tv_usec = advskew * 1000000 / 256;
936 	}
937 
938 	ch.carp_version = CARP_VERSION;
939 	ch.carp_type = CARP_ADVERTISEMENT;
940 	ch.carp_vhid = sc->sc_vhid;
941 	ch.carp_advbase = advbase;
942 	ch.carp_advskew = advskew;
943 	ch.carp_authlen = 7;	/* XXX DEFINE */
944 	ch.carp_pad1 = 0;	/* must be zero */
945 	ch.carp_cksum = 0;
946 
947 #ifdef INET
948 	if (sc->sc_ia) {
949 		struct ip *ip;
950 
951 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
952 		if (m == NULL) {
953 			SC2IFP(sc)->if_oerrors++;
954 			CARPSTATS_INC(carps_onomem);
955 			/* XXX maybe less ? */
956 			if (advbase != 255 || advskew != 255)
957 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
958 				    carp_send_ad, sc);
959 			return;
960 		}
961 		len = sizeof(*ip) + sizeof(ch);
962 		m->m_pkthdr.len = len;
963 		m->m_pkthdr.rcvif = NULL;
964 		m->m_len = len;
965 		MH_ALIGN(m, m->m_len);
966 		m->m_flags |= M_MCAST;
967 		ip = mtod(m, struct ip *);
968 		ip->ip_v = IPVERSION;
969 		ip->ip_hl = sizeof(*ip) >> 2;
970 		ip->ip_tos = IPTOS_LOWDELAY;
971 		ip->ip_len = len;
972 		ip->ip_id = ip_newid();
973 		ip->ip_off = IP_DF;
974 		ip->ip_ttl = CARP_DFLTTL;
975 		ip->ip_p = IPPROTO_CARP;
976 		ip->ip_sum = 0;
977 		ip->ip_src.s_addr = sc->sc_ia->ia_addr.sin_addr.s_addr;
978 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
979 
980 		ch_ptr = (struct carp_header *)(&ip[1]);
981 		bcopy(&ch, ch_ptr, sizeof(ch));
982 		if (carp_prepare_ad(m, sc, ch_ptr))
983 			return;
984 
985 		m->m_data += sizeof(*ip);
986 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip));
987 		m->m_data -= sizeof(*ip);
988 
989 		getmicrotime(&SC2IFP(sc)->if_lastchange);
990 		SC2IFP(sc)->if_opackets++;
991 		SC2IFP(sc)->if_obytes += len;
992 		CARPSTATS_INC(carps_opackets);
993 
994 		if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)) {
995 			SC2IFP(sc)->if_oerrors++;
996 			if (sc->sc_sendad_errors < INT_MAX)
997 				sc->sc_sendad_errors++;
998 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
999 				carp_suppress_preempt++;
1000 				if (carp_suppress_preempt == 1) {
1001 					CARP_SCUNLOCK(sc);
1002 					carp_send_ad_all();
1003 					CARP_SCLOCK(sc);
1004 				}
1005 			}
1006 			sc->sc_sendad_success = 0;
1007 		} else {
1008 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1009 				if (++sc->sc_sendad_success >=
1010 				    CARP_SENDAD_MIN_SUCCESS) {
1011 					carp_suppress_preempt--;
1012 					sc->sc_sendad_errors = 0;
1013 				}
1014 			} else
1015 				sc->sc_sendad_errors = 0;
1016 		}
1017 	}
1018 #endif /* INET */
1019 #ifdef INET6
1020 	if (sc->sc_ia6) {
1021 		struct ip6_hdr *ip6;
1022 
1023 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
1024 		if (m == NULL) {
1025 			SC2IFP(sc)->if_oerrors++;
1026 			CARPSTATS_INC(carps_onomem);
1027 			/* XXX maybe less ? */
1028 			if (advbase != 255 || advskew != 255)
1029 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1030 				    carp_send_ad, sc);
1031 			return;
1032 		}
1033 		len = sizeof(*ip6) + sizeof(ch);
1034 		m->m_pkthdr.len = len;
1035 		m->m_pkthdr.rcvif = NULL;
1036 		m->m_len = len;
1037 		MH_ALIGN(m, m->m_len);
1038 		m->m_flags |= M_MCAST;
1039 		ip6 = mtod(m, struct ip6_hdr *);
1040 		bzero(ip6, sizeof(*ip6));
1041 		ip6->ip6_vfc |= IPV6_VERSION;
1042 		ip6->ip6_hlim = CARP_DFLTTL;
1043 		ip6->ip6_nxt = IPPROTO_CARP;
1044 		bcopy(&sc->sc_ia6->ia_addr.sin6_addr, &ip6->ip6_src,
1045 		    sizeof(struct in6_addr));
1046 		/* set the multicast destination */
1047 
1048 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1049 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1050 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1051 			SC2IFP(sc)->if_oerrors++;
1052 			m_freem(m);
1053 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1054 			return;
1055 		}
1056 
1057 		ch_ptr = (struct carp_header *)(&ip6[1]);
1058 		bcopy(&ch, ch_ptr, sizeof(ch));
1059 		if (carp_prepare_ad(m, sc, ch_ptr))
1060 			return;
1061 
1062 		m->m_data += sizeof(*ip6);
1063 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip6));
1064 		m->m_data -= sizeof(*ip6);
1065 
1066 		getmicrotime(&SC2IFP(sc)->if_lastchange);
1067 		SC2IFP(sc)->if_opackets++;
1068 		SC2IFP(sc)->if_obytes += len;
1069 		CARPSTATS_INC(carps_opackets6);
1070 
1071 		if (ip6_output(m, NULL, NULL, 0, &sc->sc_im6o, NULL, NULL)) {
1072 			SC2IFP(sc)->if_oerrors++;
1073 			if (sc->sc_sendad_errors < INT_MAX)
1074 				sc->sc_sendad_errors++;
1075 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
1076 				carp_suppress_preempt++;
1077 				if (carp_suppress_preempt == 1) {
1078 					CARP_SCUNLOCK(sc);
1079 					carp_send_ad_all();
1080 					CARP_SCLOCK(sc);
1081 				}
1082 			}
1083 			sc->sc_sendad_success = 0;
1084 		} else {
1085 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1086 				if (++sc->sc_sendad_success >=
1087 				    CARP_SENDAD_MIN_SUCCESS) {
1088 					carp_suppress_preempt--;
1089 					sc->sc_sendad_errors = 0;
1090 				}
1091 			} else
1092 				sc->sc_sendad_errors = 0;
1093 		}
1094 	}
1095 #endif /* INET6 */
1096 
1097 	if (advbase != 255 || advskew != 255)
1098 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1099 		    carp_send_ad, sc);
1100 
1101 }
1102 
1103 /*
1104  * Broadcast a gratuitous ARP request containing
1105  * the virtual router MAC address for each IP address
1106  * associated with the virtual router.
1107  */
1108 static void
1109 carp_send_arp(struct carp_softc *sc)
1110 {
1111 	struct ifaddr *ifa;
1112 
1113 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1114 
1115 		if (ifa->ifa_addr->sa_family != AF_INET)
1116 			continue;
1117 
1118 /*		arprequest(sc->sc_carpdev, &in, &in, IF_LLADDR(sc->sc_ifp)); */
1119 		arp_ifinit2(sc->sc_carpdev, ifa, IF_LLADDR(sc->sc_ifp));
1120 
1121 		DELAY(1000);	/* XXX */
1122 	}
1123 }
1124 
1125 #ifdef INET6
1126 static void
1127 carp_send_na(struct carp_softc *sc)
1128 {
1129 	struct ifaddr *ifa;
1130 	struct in6_addr *in6;
1131 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1132 
1133 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1134 
1135 		if (ifa->ifa_addr->sa_family != AF_INET6)
1136 			continue;
1137 
1138 		in6 = &ifatoia6(ifa)->ia_addr.sin6_addr;
1139 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1140 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1141 		DELAY(1000);	/* XXX */
1142 	}
1143 }
1144 #endif /* INET6 */
1145 
1146 static int
1147 carp_addrcount(struct carp_if *cif, struct in_ifaddr *ia, int type)
1148 {
1149 	struct carp_softc *vh;
1150 	struct ifaddr *ifa;
1151 	int count = 0;
1152 
1153 	CARP_LOCK_ASSERT(cif);
1154 
1155 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1156 		if ((type == CARP_COUNT_RUNNING &&
1157 		    (SC2IFP(vh)->if_flags & IFF_UP) &&
1158 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) ||
1159 		    (type == CARP_COUNT_MASTER && vh->sc_state == MASTER)) {
1160 			IF_ADDR_LOCK(SC2IFP(vh));
1161 			TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1162 			    ifa_list) {
1163 				if (ifa->ifa_addr->sa_family == AF_INET &&
1164 				    ia->ia_addr.sin_addr.s_addr ==
1165 				    ifatoia(ifa)->ia_addr.sin_addr.s_addr)
1166 					count++;
1167 			}
1168 			IF_ADDR_UNLOCK(SC2IFP(vh));
1169 		}
1170 	}
1171 	return (count);
1172 }
1173 
1174 int
1175 carp_iamatch(struct ifnet *ifp, struct in_ifaddr *ia,
1176     struct in_addr *isaddr, u_int8_t **enaddr)
1177 {
1178 	struct carp_if *cif;
1179 	struct carp_softc *vh;
1180 	int index, count = 0;
1181 	struct ifaddr *ifa;
1182 
1183 	cif = ifp->if_carp;
1184 	CARP_LOCK(cif);
1185 
1186 	if (carp_opts[CARPCTL_ARPBALANCE]) {
1187 		/*
1188 		 * XXX proof of concept implementation.
1189 		 * We use the source ip to decide which virtual host should
1190 		 * handle the request. If we're master of that virtual host,
1191 		 * then we respond, otherwise, just drop the arp packet on
1192 		 * the floor.
1193 		 */
1194 		count = carp_addrcount(cif, ia, CARP_COUNT_RUNNING);
1195 		if (count == 0) {
1196 			/* should never reach this */
1197 			CARP_UNLOCK(cif);
1198 			return (0);
1199 		}
1200 
1201 		/* this should be a hash, like pf_hash() */
1202 		index = ntohl(isaddr->s_addr) % count;
1203 		count = 0;
1204 
1205 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1206 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1207 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) {
1208 				IF_ADDR_LOCK(SC2IFP(vh));
1209 				TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1210 				    ifa_list) {
1211 					if (ifa->ifa_addr->sa_family ==
1212 					    AF_INET &&
1213 					    ia->ia_addr.sin_addr.s_addr ==
1214 					    ifatoia(ifa)->ia_addr.sin_addr.s_addr) {
1215 						if (count == index) {
1216 							if (vh->sc_state ==
1217 							    MASTER) {
1218 								*enaddr = IF_LLADDR(vh->sc_ifp);
1219 								IF_ADDR_UNLOCK(SC2IFP(vh));
1220 								CARP_UNLOCK(cif);
1221 								return (1);
1222 							} else {
1223 								IF_ADDR_UNLOCK(SC2IFP(vh));
1224 								CARP_UNLOCK(cif);
1225 								return (0);
1226 							}
1227 						}
1228 						count++;
1229 					}
1230 				}
1231 				IF_ADDR_UNLOCK(SC2IFP(vh));
1232 			}
1233 		}
1234 	} else {
1235 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1236 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1237 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1238 			    ia->ia_ifp == SC2IFP(vh) &&
1239 			    vh->sc_state == MASTER) {
1240 				*enaddr = IF_LLADDR(vh->sc_ifp);
1241 				CARP_UNLOCK(cif);
1242 				return (1);
1243 			}
1244 		}
1245 	}
1246 	CARP_UNLOCK(cif);
1247 	return (0);
1248 }
1249 
1250 #ifdef INET6
1251 struct ifaddr *
1252 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1253 {
1254 	struct carp_if *cif;
1255 	struct carp_softc *vh;
1256 	struct ifaddr *ifa;
1257 
1258 	cif = ifp->if_carp;
1259 	CARP_LOCK(cif);
1260 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1261 		IF_ADDR_LOCK(SC2IFP(vh));
1262 		TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist, ifa_list) {
1263 			if (IN6_ARE_ADDR_EQUAL(taddr,
1264 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1265  			    (SC2IFP(vh)->if_flags & IFF_UP) &&
1266 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1267 			    vh->sc_state == MASTER) {
1268 				ifa_ref(ifa);
1269 				IF_ADDR_UNLOCK(SC2IFP(vh));
1270 			    	CARP_UNLOCK(cif);
1271 				return (ifa);
1272 			}
1273 		}
1274 		IF_ADDR_UNLOCK(SC2IFP(vh));
1275 	}
1276 	CARP_UNLOCK(cif);
1277 
1278 	return (NULL);
1279 }
1280 
1281 caddr_t
1282 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1283 {
1284 	struct m_tag *mtag;
1285 	struct carp_if *cif;
1286 	struct carp_softc *sc;
1287 	struct ifaddr *ifa;
1288 
1289 	cif = ifp->if_carp;
1290 	CARP_LOCK(cif);
1291 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
1292 		IF_ADDR_LOCK(SC2IFP(sc));
1293 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1294 			if (IN6_ARE_ADDR_EQUAL(taddr,
1295 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1296  			    (SC2IFP(sc)->if_flags & IFF_UP) &&
1297 			    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING)) {
1298 				struct ifnet *ifp = SC2IFP(sc);
1299 				mtag = m_tag_get(PACKET_TAG_CARP,
1300 				    sizeof(struct ifnet *), M_NOWAIT);
1301 				if (mtag == NULL) {
1302 					/* better a bit than nothing */
1303 					IF_ADDR_UNLOCK(SC2IFP(sc));
1304 					CARP_UNLOCK(cif);
1305 					return (IF_LLADDR(sc->sc_ifp));
1306 				}
1307 				bcopy(&ifp, (caddr_t)(mtag + 1),
1308 				    sizeof(struct ifnet *));
1309 				m_tag_prepend(m, mtag);
1310 
1311 				IF_ADDR_UNLOCK(SC2IFP(sc));
1312 				CARP_UNLOCK(cif);
1313 				return (IF_LLADDR(sc->sc_ifp));
1314 			}
1315 		}
1316 		IF_ADDR_UNLOCK(SC2IFP(sc));
1317 	}
1318 	CARP_UNLOCK(cif);
1319 
1320 	return (NULL);
1321 }
1322 #endif
1323 
1324 struct ifnet *
1325 carp_forus(struct ifnet *ifp, u_char *dhost)
1326 {
1327 	struct carp_if *cif;
1328 	struct carp_softc *vh;
1329 	u_int8_t *ena = dhost;
1330 
1331 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1332 		return (NULL);
1333 
1334 	cif = ifp->if_carp;
1335 	CARP_LOCK(cif);
1336 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list)
1337 		if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1338 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1339 		    vh->sc_state == MASTER &&
1340 		    !bcmp(dhost, IF_LLADDR(vh->sc_ifp), ETHER_ADDR_LEN)) {
1341 		    	CARP_UNLOCK(cif);
1342 			return (SC2IFP(vh));
1343 		}
1344 
1345     	CARP_UNLOCK(cif);
1346 	return (NULL);
1347 }
1348 
1349 static void
1350 carp_master_down(void *v)
1351 {
1352 	struct carp_softc *sc = v;
1353 
1354 	CARP_SCLOCK(sc);
1355 	carp_master_down_locked(sc);
1356 	CARP_SCUNLOCK(sc);
1357 }
1358 
1359 static void
1360 carp_master_down_locked(struct carp_softc *sc)
1361 {
1362 	if (sc->sc_carpdev)
1363 		CARP_SCLOCK_ASSERT(sc);
1364 
1365 	switch (sc->sc_state) {
1366 	case INIT:
1367 		printf("%s: master_down event in INIT state\n",
1368 		    SC2IFP(sc)->if_xname);
1369 		break;
1370 	case MASTER:
1371 		break;
1372 	case BACKUP:
1373 		carp_set_state(sc, MASTER);
1374 		carp_send_ad_locked(sc);
1375 		carp_send_arp(sc);
1376 #ifdef INET6
1377 		carp_send_na(sc);
1378 #endif /* INET6 */
1379 		carp_setrun(sc, 0);
1380 		carp_setroute(sc, RTM_ADD);
1381 		break;
1382 	}
1383 }
1384 
1385 /*
1386  * When in backup state, af indicates whether to reset the master down timer
1387  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1388  */
1389 static void
1390 carp_setrun(struct carp_softc *sc, sa_family_t af)
1391 {
1392 	struct timeval tv;
1393 
1394 	if (sc->sc_carpdev == NULL) {
1395 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1396 		carp_set_state(sc, INIT);
1397 		return;
1398 	} else
1399 		CARP_SCLOCK_ASSERT(sc);
1400 
1401 	if (SC2IFP(sc)->if_flags & IFF_UP &&
1402 	    sc->sc_vhid > 0 && (sc->sc_naddrs || sc->sc_naddrs6) &&
1403 	    sc->sc_carpdev->if_link_state == LINK_STATE_UP)
1404 		SC2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
1405 	else {
1406 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1407 		carp_setroute(sc, RTM_DELETE);
1408 		return;
1409 	}
1410 
1411 	switch (sc->sc_state) {
1412 	case INIT:
1413 		if (carp_opts[CARPCTL_PREEMPT] && !carp_suppress_preempt) {
1414 			carp_send_ad_locked(sc);
1415 			carp_send_arp(sc);
1416 #ifdef INET6
1417 			carp_send_na(sc);
1418 #endif /* INET6 */
1419 			CARP_LOG("%s: INIT -> MASTER (preempting)\n",
1420 			    SC2IFP(sc)->if_xname);
1421 			carp_set_state(sc, MASTER);
1422 			carp_setroute(sc, RTM_ADD);
1423 		} else {
1424 			CARP_LOG("%s: INIT -> BACKUP\n", SC2IFP(sc)->if_xname);
1425 			carp_set_state(sc, BACKUP);
1426 			carp_setroute(sc, RTM_DELETE);
1427 			carp_setrun(sc, 0);
1428 		}
1429 		break;
1430 	case BACKUP:
1431 		callout_stop(&sc->sc_ad_tmo);
1432 		tv.tv_sec = 3 * sc->sc_advbase;
1433 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1434 		switch (af) {
1435 #ifdef INET
1436 		case AF_INET:
1437 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1438 			    carp_master_down, sc);
1439 			break;
1440 #endif /* INET */
1441 #ifdef INET6
1442 		case AF_INET6:
1443 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1444 			    carp_master_down, sc);
1445 			break;
1446 #endif /* INET6 */
1447 		default:
1448 			if (sc->sc_naddrs)
1449 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1450 				    carp_master_down, sc);
1451 			if (sc->sc_naddrs6)
1452 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1453 				    carp_master_down, sc);
1454 			break;
1455 		}
1456 		break;
1457 	case MASTER:
1458 		tv.tv_sec = sc->sc_advbase;
1459 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1460 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1461 		    carp_send_ad, sc);
1462 		break;
1463 	}
1464 }
1465 
1466 static void
1467 carp_multicast_cleanup(struct carp_softc *sc)
1468 {
1469 	struct ip_moptions *imo = &sc->sc_imo;
1470 	u_int16_t n = imo->imo_num_memberships;
1471 
1472 	/* Clean up our own multicast memberships */
1473 	while (n-- > 0) {
1474 		if (imo->imo_membership[n] != NULL) {
1475 			in_delmulti(imo->imo_membership[n]);
1476 			imo->imo_membership[n] = NULL;
1477 		}
1478 	}
1479 	KASSERT(imo->imo_mfilters == NULL,
1480 	   ("%s: imo_mfilters != NULL", __func__));
1481 	imo->imo_num_memberships = 0;
1482 	imo->imo_multicast_ifp = NULL;
1483 }
1484 
1485 #ifdef INET6
1486 static void
1487 carp_multicast6_cleanup(struct carp_softc *sc)
1488 {
1489 	struct ip6_moptions *im6o = &sc->sc_im6o;
1490 	u_int16_t n = im6o->im6o_num_memberships;
1491 
1492 	while (n-- > 0) {
1493 		if (im6o->im6o_membership[n] != NULL) {
1494 			in6_mc_leave(im6o->im6o_membership[n], NULL);
1495 			im6o->im6o_membership[n] = NULL;
1496 		}
1497 	}
1498 	KASSERT(im6o->im6o_mfilters == NULL,
1499 	   ("%s: im6o_mfilters != NULL", __func__));
1500 	im6o->im6o_num_memberships = 0;
1501 	im6o->im6o_multicast_ifp = NULL;
1502 }
1503 #endif
1504 
1505 static int
1506 carp_set_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1507 {
1508 	struct ifnet *ifp;
1509 	struct carp_if *cif;
1510 	struct in_ifaddr *ia, *ia_if;
1511 	struct ip_moptions *imo = &sc->sc_imo;
1512 	struct in_addr addr;
1513 	u_long iaddr = htonl(sin->sin_addr.s_addr);
1514 	int own, error;
1515 
1516 	if (sin->sin_addr.s_addr == 0) {
1517 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1518 			carp_set_state(sc, INIT);
1519 		if (sc->sc_naddrs)
1520 			SC2IFP(sc)->if_flags |= IFF_UP;
1521 		if (sc->sc_carpdev)
1522 			CARP_SCLOCK(sc);
1523 		carp_setrun(sc, 0);
1524 		if (sc->sc_carpdev)
1525 			CARP_SCUNLOCK(sc);
1526 		return (0);
1527 	}
1528 
1529 	/* we have to do it by hands to check we won't match on us */
1530 	ia_if = NULL; own = 0;
1531 	IN_IFADDR_RLOCK();
1532 	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
1533 		/* and, yeah, we need a multicast-capable iface too */
1534 		if (ia->ia_ifp != SC2IFP(sc) &&
1535 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1536 		    (iaddr & ia->ia_subnetmask) == ia->ia_subnet) {
1537 			if (!ia_if)
1538 				ia_if = ia;
1539 			if (sin->sin_addr.s_addr ==
1540 			    ia->ia_addr.sin_addr.s_addr)
1541 				own++;
1542 		}
1543 	}
1544 
1545 	if (!ia_if) {
1546 		IN_IFADDR_RUNLOCK();
1547 		return (EADDRNOTAVAIL);
1548 	}
1549 
1550 	ia = ia_if;
1551 	ifa_ref(&ia->ia_ifa);
1552 	IN_IFADDR_RUNLOCK();
1553 
1554 	ifp = ia->ia_ifp;
1555 
1556 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1557 	    (imo->imo_multicast_ifp && imo->imo_multicast_ifp != ifp)) {
1558 		ifa_free(&ia->ia_ifa);
1559 		return (EADDRNOTAVAIL);
1560 	}
1561 
1562 	if (imo->imo_num_memberships == 0) {
1563 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1564 		if ((imo->imo_membership[0] = in_addmulti(&addr, ifp)) ==
1565 		    NULL) {
1566 			ifa_free(&ia->ia_ifa);
1567 			return (ENOBUFS);
1568 		}
1569 		imo->imo_num_memberships++;
1570 		imo->imo_multicast_ifp = ifp;
1571 		imo->imo_multicast_ttl = CARP_DFLTTL;
1572 		imo->imo_multicast_loop = 0;
1573 	}
1574 
1575 	if (!ifp->if_carp) {
1576 
1577 		cif = malloc(sizeof(*cif), M_CARP,
1578 		    M_WAITOK|M_ZERO);
1579 		if (!cif) {
1580 			error = ENOBUFS;
1581 			goto cleanup;
1582 		}
1583 		if ((error = ifpromisc(ifp, 1))) {
1584 			free(cif, M_CARP);
1585 			goto cleanup;
1586 		}
1587 
1588 		CARP_LOCK_INIT(cif);
1589 		CARP_LOCK(cif);
1590 		cif->vhif_ifp = ifp;
1591 		TAILQ_INIT(&cif->vhif_vrs);
1592 		ifp->if_carp = cif;
1593 
1594 	} else {
1595 		struct carp_softc *vr;
1596 
1597 		cif = (struct carp_if *)ifp->if_carp;
1598 		CARP_LOCK(cif);
1599 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1600 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1601 				CARP_UNLOCK(cif);
1602 				error = EEXIST;
1603 				goto cleanup;
1604 			}
1605 	}
1606 	sc->sc_ia = ia;
1607 	sc->sc_carpdev = ifp;
1608 
1609 	{ /* XXX prevent endless loop if already in queue */
1610 	struct carp_softc *vr, *after = NULL;
1611 	int myself = 0;
1612 	cif = (struct carp_if *)ifp->if_carp;
1613 
1614 	/* XXX: cif should not change, right? So we still hold the lock */
1615 	CARP_LOCK_ASSERT(cif);
1616 
1617 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1618 		if (vr == sc)
1619 			myself = 1;
1620 		if (vr->sc_vhid < sc->sc_vhid)
1621 			after = vr;
1622 	}
1623 
1624 	if (!myself) {
1625 		/* We're trying to keep things in order */
1626 		if (after == NULL) {
1627 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1628 		} else {
1629 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1630 		}
1631 		cif->vhif_nvrs++;
1632 	}
1633 	}
1634 
1635 	sc->sc_naddrs++;
1636 	SC2IFP(sc)->if_flags |= IFF_UP;
1637 	if (own)
1638 		sc->sc_advskew = 0;
1639 	carp_sc_state_locked(sc);
1640 	carp_setrun(sc, 0);
1641 
1642 	CARP_UNLOCK(cif);
1643 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1644 
1645 	return (0);
1646 
1647 cleanup:
1648 	in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1649 	ifa_free(&ia->ia_ifa);
1650 	return (error);
1651 }
1652 
1653 static int
1654 carp_del_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1655 {
1656 	int error = 0;
1657 
1658 	if (!--sc->sc_naddrs) {
1659 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1660 		struct ip_moptions *imo = &sc->sc_imo;
1661 
1662 		CARP_LOCK(cif);
1663 		callout_stop(&sc->sc_ad_tmo);
1664 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1665 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1666 		sc->sc_vhid = -1;
1667 		in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1668 		imo->imo_multicast_ifp = NULL;
1669 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1670 		if (!--cif->vhif_nvrs) {
1671 			sc->sc_carpdev->if_carp = NULL;
1672 			CARP_LOCK_DESTROY(cif);
1673 			free(cif, M_CARP);
1674 		} else {
1675 			CARP_UNLOCK(cif);
1676 		}
1677 	}
1678 
1679 	return (error);
1680 }
1681 
1682 #ifdef INET6
1683 static int
1684 carp_set_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1685 {
1686 	struct ifnet *ifp;
1687 	struct carp_if *cif;
1688 	struct in6_ifaddr *ia, *ia_if;
1689 	struct ip6_moptions *im6o = &sc->sc_im6o;
1690 	struct in6_addr in6;
1691 	int own, error;
1692 
1693 	error = 0;
1694 
1695 	if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
1696 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1697 			carp_set_state(sc, INIT);
1698 		if (sc->sc_naddrs6)
1699 			SC2IFP(sc)->if_flags |= IFF_UP;
1700 		if (sc->sc_carpdev)
1701 			CARP_SCLOCK(sc);
1702 		carp_setrun(sc, 0);
1703 		if (sc->sc_carpdev)
1704 			CARP_SCUNLOCK(sc);
1705 		return (0);
1706 	}
1707 
1708 	/* we have to do it by hands to check we won't match on us */
1709 	ia_if = NULL; own = 0;
1710 	IN6_IFADDR_RLOCK();
1711 	TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
1712 		int i;
1713 
1714 		for (i = 0; i < 4; i++) {
1715 			if ((sin6->sin6_addr.s6_addr32[i] &
1716 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]) !=
1717 			    (ia->ia_addr.sin6_addr.s6_addr32[i] &
1718 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]))
1719 				break;
1720 		}
1721 		/* and, yeah, we need a multicast-capable iface too */
1722 		if (ia->ia_ifp != SC2IFP(sc) &&
1723 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1724 		    (i == 4)) {
1725 			if (!ia_if)
1726 				ia_if = ia;
1727 			if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr,
1728 			    &ia->ia_addr.sin6_addr))
1729 				own++;
1730 		}
1731 	}
1732 
1733 	if (!ia_if) {
1734 		IN6_IFADDR_RUNLOCK();
1735 		return (EADDRNOTAVAIL);
1736 	}
1737 	ia = ia_if;
1738 	ifa_ref(&ia->ia_ifa);
1739 	IN6_IFADDR_RUNLOCK();
1740 	ifp = ia->ia_ifp;
1741 
1742 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1743 	    (im6o->im6o_multicast_ifp && im6o->im6o_multicast_ifp != ifp)) {
1744 		ifa_free(&ia->ia_ifa);
1745 		return (EADDRNOTAVAIL);
1746 	}
1747 
1748 	if (!sc->sc_naddrs6) {
1749 		struct in6_multi *in6m;
1750 
1751 		im6o->im6o_multicast_ifp = ifp;
1752 
1753 		/* join CARP multicast address */
1754 		bzero(&in6, sizeof(in6));
1755 		in6.s6_addr16[0] = htons(0xff02);
1756 		in6.s6_addr8[15] = 0x12;
1757 		if (in6_setscope(&in6, ifp, NULL) != 0)
1758 			goto cleanup;
1759 		in6m = NULL;
1760 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1761 		if (error)
1762 			goto cleanup;
1763 		im6o->im6o_membership[0] = in6m;
1764 		im6o->im6o_num_memberships++;
1765 
1766 		/* join solicited multicast address */
1767 		bzero(&in6, sizeof(in6));
1768 		in6.s6_addr16[0] = htons(0xff02);
1769 		in6.s6_addr32[1] = 0;
1770 		in6.s6_addr32[2] = htonl(1);
1771 		in6.s6_addr32[3] = sin6->sin6_addr.s6_addr32[3];
1772 		in6.s6_addr8[12] = 0xff;
1773 		if (in6_setscope(&in6, ifp, NULL) != 0)
1774 			goto cleanup;
1775 		in6m = NULL;
1776 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1777 		if (error)
1778 			goto cleanup;
1779 		im6o->im6o_membership[1] = in6m;
1780 		im6o->im6o_num_memberships++;
1781 	}
1782 
1783 	if (!ifp->if_carp) {
1784 		cif = malloc(sizeof(*cif), M_CARP,
1785 		    M_WAITOK|M_ZERO);
1786 		if (!cif) {
1787 			error = ENOBUFS;
1788 			goto cleanup;
1789 		}
1790 		if ((error = ifpromisc(ifp, 1))) {
1791 			free(cif, M_CARP);
1792 			goto cleanup;
1793 		}
1794 
1795 		CARP_LOCK_INIT(cif);
1796 		CARP_LOCK(cif);
1797 		cif->vhif_ifp = ifp;
1798 		TAILQ_INIT(&cif->vhif_vrs);
1799 		ifp->if_carp = cif;
1800 
1801 	} else {
1802 		struct carp_softc *vr;
1803 
1804 		cif = (struct carp_if *)ifp->if_carp;
1805 		CARP_LOCK(cif);
1806 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1807 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1808 				CARP_UNLOCK(cif);
1809 				error = EINVAL;
1810 				goto cleanup;
1811 			}
1812 	}
1813 	sc->sc_ia6 = ia;
1814 	sc->sc_carpdev = ifp;
1815 
1816 	{ /* XXX prevent endless loop if already in queue */
1817 	struct carp_softc *vr, *after = NULL;
1818 	int myself = 0;
1819 	cif = (struct carp_if *)ifp->if_carp;
1820 	CARP_LOCK_ASSERT(cif);
1821 
1822 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1823 		if (vr == sc)
1824 			myself = 1;
1825 		if (vr->sc_vhid < sc->sc_vhid)
1826 			after = vr;
1827 	}
1828 
1829 	if (!myself) {
1830 		/* We're trying to keep things in order */
1831 		if (after == NULL) {
1832 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1833 		} else {
1834 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1835 		}
1836 		cif->vhif_nvrs++;
1837 	}
1838 	}
1839 
1840 	sc->sc_naddrs6++;
1841 	SC2IFP(sc)->if_flags |= IFF_UP;
1842 	if (own)
1843 		sc->sc_advskew = 0;
1844 	carp_sc_state_locked(sc);
1845 	carp_setrun(sc, 0);
1846 
1847 	CARP_UNLOCK(cif);
1848 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1849 
1850 	return (0);
1851 
1852 cleanup:
1853 	if (!sc->sc_naddrs6)
1854 		carp_multicast6_cleanup(sc);
1855 	ifa_free(&ia->ia_ifa);
1856 	return (error);
1857 }
1858 
1859 static int
1860 carp_del_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1861 {
1862 	int error = 0;
1863 
1864 	if (!--sc->sc_naddrs6) {
1865 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1866 
1867 		CARP_LOCK(cif);
1868 		callout_stop(&sc->sc_ad_tmo);
1869 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1870 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1871 		sc->sc_vhid = -1;
1872 		carp_multicast6_cleanup(sc);
1873 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1874 		if (!--cif->vhif_nvrs) {
1875 			CARP_LOCK_DESTROY(cif);
1876 			sc->sc_carpdev->if_carp = NULL;
1877 			free(cif, M_CARP);
1878 		} else
1879 			CARP_UNLOCK(cif);
1880 	}
1881 
1882 	return (error);
1883 }
1884 #endif /* INET6 */
1885 
1886 static int
1887 carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
1888 {
1889 	struct carp_softc *sc = ifp->if_softc, *vr;
1890 	struct carpreq carpr;
1891 	struct ifaddr *ifa;
1892 	struct ifreq *ifr;
1893 	struct ifaliasreq *ifra;
1894 	int locked = 0, error = 0;
1895 
1896 	ifa = (struct ifaddr *)addr;
1897 	ifra = (struct ifaliasreq *)addr;
1898 	ifr = (struct ifreq *)addr;
1899 
1900 	switch (cmd) {
1901 	case SIOCSIFADDR:
1902 		switch (ifa->ifa_addr->sa_family) {
1903 #ifdef INET
1904 		case AF_INET:
1905 			SC2IFP(sc)->if_flags |= IFF_UP;
1906 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1907 			    sizeof(struct sockaddr));
1908 			error = carp_set_addr(sc, satosin(ifa->ifa_addr));
1909 			break;
1910 #endif /* INET */
1911 #ifdef INET6
1912 		case AF_INET6:
1913 			SC2IFP(sc)->if_flags |= IFF_UP;
1914 			error = carp_set_addr6(sc, satosin6(ifa->ifa_addr));
1915 			break;
1916 #endif /* INET6 */
1917 		default:
1918 			error = EAFNOSUPPORT;
1919 			break;
1920 		}
1921 		break;
1922 
1923 	case SIOCAIFADDR:
1924 		switch (ifa->ifa_addr->sa_family) {
1925 #ifdef INET
1926 		case AF_INET:
1927 			SC2IFP(sc)->if_flags |= IFF_UP;
1928 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1929 			    sizeof(struct sockaddr));
1930 			error = carp_set_addr(sc, satosin(&ifra->ifra_addr));
1931 			break;
1932 #endif /* INET */
1933 #ifdef INET6
1934 		case AF_INET6:
1935 			SC2IFP(sc)->if_flags |= IFF_UP;
1936 			error = carp_set_addr6(sc, satosin6(&ifra->ifra_addr));
1937 			break;
1938 #endif /* INET6 */
1939 		default:
1940 			error = EAFNOSUPPORT;
1941 			break;
1942 		}
1943 		break;
1944 
1945 	case SIOCDIFADDR:
1946 		switch (ifa->ifa_addr->sa_family) {
1947 #ifdef INET
1948 		case AF_INET:
1949 			error = carp_del_addr(sc, satosin(&ifra->ifra_addr));
1950 			break;
1951 #endif /* INET */
1952 #ifdef INET6
1953 		case AF_INET6:
1954 			error = carp_del_addr6(sc, satosin6(&ifra->ifra_addr));
1955 			break;
1956 #endif /* INET6 */
1957 		default:
1958 			error = EAFNOSUPPORT;
1959 			break;
1960 		}
1961 		break;
1962 
1963 	case SIOCSIFFLAGS:
1964 		if (sc->sc_carpdev) {
1965 			locked = 1;
1966 			CARP_SCLOCK(sc);
1967 		}
1968 		if (sc->sc_state != INIT && !(ifr->ifr_flags & IFF_UP)) {
1969  			callout_stop(&sc->sc_ad_tmo);
1970  			callout_stop(&sc->sc_md_tmo);
1971  			callout_stop(&sc->sc_md6_tmo);
1972 			if (sc->sc_state == MASTER)
1973 				carp_send_ad_locked(sc);
1974 			carp_set_state(sc, INIT);
1975 			carp_setrun(sc, 0);
1976 		} else if (sc->sc_state == INIT && (ifr->ifr_flags & IFF_UP)) {
1977 			SC2IFP(sc)->if_flags |= IFF_UP;
1978 			carp_setrun(sc, 0);
1979 		}
1980 		break;
1981 
1982 	case SIOCSVH:
1983 		error = priv_check(curthread, PRIV_NETINET_CARP);
1984 		if (error)
1985 			break;
1986 		if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1987 			break;
1988 		error = 1;
1989 		if (sc->sc_carpdev) {
1990 			locked = 1;
1991 			CARP_SCLOCK(sc);
1992 		}
1993 		if (sc->sc_state != INIT && carpr.carpr_state != sc->sc_state) {
1994 			switch (carpr.carpr_state) {
1995 			case BACKUP:
1996 				callout_stop(&sc->sc_ad_tmo);
1997 				carp_set_state(sc, BACKUP);
1998 				carp_setrun(sc, 0);
1999 				carp_setroute(sc, RTM_DELETE);
2000 				break;
2001 			case MASTER:
2002 				carp_master_down_locked(sc);
2003 				break;
2004 			default:
2005 				break;
2006 			}
2007 		}
2008 		if (carpr.carpr_vhid > 0) {
2009 			if (carpr.carpr_vhid > 255) {
2010 				error = EINVAL;
2011 				break;
2012 			}
2013 			if (sc->sc_carpdev) {
2014 				struct carp_if *cif;
2015 				cif = (struct carp_if *)sc->sc_carpdev->if_carp;
2016 				TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
2017 					if (vr != sc &&
2018 					    vr->sc_vhid == carpr.carpr_vhid) {
2019 						error = EEXIST;
2020 						break;
2021 					}
2022 				if (error == EEXIST)
2023 					break;
2024 			}
2025 			sc->sc_vhid = carpr.carpr_vhid;
2026 			IF_LLADDR(sc->sc_ifp)[0] = 0;
2027 			IF_LLADDR(sc->sc_ifp)[1] = 0;
2028 			IF_LLADDR(sc->sc_ifp)[2] = 0x5e;
2029 			IF_LLADDR(sc->sc_ifp)[3] = 0;
2030 			IF_LLADDR(sc->sc_ifp)[4] = 1;
2031 			IF_LLADDR(sc->sc_ifp)[5] = sc->sc_vhid;
2032 			error--;
2033 		}
2034 		if (carpr.carpr_advbase > 0 || carpr.carpr_advskew > 0) {
2035 			if (carpr.carpr_advskew >= 255) {
2036 				error = EINVAL;
2037 				break;
2038 			}
2039 			if (carpr.carpr_advbase > 255) {
2040 				error = EINVAL;
2041 				break;
2042 			}
2043 			sc->sc_advbase = carpr.carpr_advbase;
2044 			sc->sc_advskew = carpr.carpr_advskew;
2045 			error--;
2046 		}
2047 		bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
2048 		if (error > 0)
2049 			error = EINVAL;
2050 		else {
2051 			error = 0;
2052 			carp_setrun(sc, 0);
2053 		}
2054 		break;
2055 
2056 	case SIOCGVH:
2057 		/* XXX: lockless read */
2058 		bzero(&carpr, sizeof(carpr));
2059 		carpr.carpr_state = sc->sc_state;
2060 		carpr.carpr_vhid = sc->sc_vhid;
2061 		carpr.carpr_advbase = sc->sc_advbase;
2062 		carpr.carpr_advskew = sc->sc_advskew;
2063 		error = priv_check(curthread, PRIV_NETINET_CARP);
2064 		if (error == 0)
2065 			bcopy(sc->sc_key, carpr.carpr_key,
2066 			    sizeof(carpr.carpr_key));
2067 		error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
2068 		break;
2069 
2070 	default:
2071 		error = EINVAL;
2072 	}
2073 
2074 	if (locked)
2075 		CARP_SCUNLOCK(sc);
2076 
2077 	carp_hmac_prepare(sc);
2078 
2079 	return (error);
2080 }
2081 
2082 /*
2083  * XXX: this is looutput. We should eventually use it from there.
2084  */
2085 static int
2086 carp_looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
2087     struct route *ro)
2088 {
2089 	u_int32_t af;
2090 	struct rtentry *rt = NULL;
2091 
2092 	M_ASSERTPKTHDR(m); /* check if we have the packet header */
2093 
2094 	if (ro != NULL)
2095 		rt = ro->ro_rt;
2096 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
2097 		m_freem(m);
2098 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
2099 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
2100 	}
2101 
2102 	ifp->if_opackets++;
2103 	ifp->if_obytes += m->m_pkthdr.len;
2104 
2105 	/* BPF writes need to be handled specially. */
2106 	if (dst->sa_family == AF_UNSPEC) {
2107 		bcopy(dst->sa_data, &af, sizeof(af));
2108 		dst->sa_family = af;
2109 	}
2110 
2111 #if 1	/* XXX */
2112 	switch (dst->sa_family) {
2113 	case AF_INET:
2114 	case AF_INET6:
2115 	case AF_IPX:
2116 	case AF_APPLETALK:
2117 		break;
2118 	default:
2119 		printf("carp_looutput: af=%d unexpected\n", dst->sa_family);
2120 		m_freem(m);
2121 		return (EAFNOSUPPORT);
2122 	}
2123 #endif
2124 	return(if_simloop(ifp, m, dst->sa_family, 0));
2125 }
2126 
2127 /*
2128  * Start output on carp interface. This function should never be called.
2129  */
2130 static void
2131 carp_start(struct ifnet *ifp)
2132 {
2133 #ifdef DEBUG
2134 	printf("%s: start called\n", ifp->if_xname);
2135 #endif
2136 }
2137 
2138 int
2139 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
2140     struct rtentry *rt)
2141 {
2142 	struct m_tag *mtag;
2143 	struct carp_softc *sc;
2144 	struct ifnet *carp_ifp;
2145 
2146 	if (!sa)
2147 		return (0);
2148 
2149 	switch (sa->sa_family) {
2150 #ifdef INET
2151 	case AF_INET:
2152 		break;
2153 #endif /* INET */
2154 #ifdef INET6
2155 	case AF_INET6:
2156 		break;
2157 #endif /* INET6 */
2158 	default:
2159 		return (0);
2160 	}
2161 
2162 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
2163 	if (mtag == NULL)
2164 		return (0);
2165 
2166 	bcopy(mtag + 1, &carp_ifp, sizeof(struct ifnet *));
2167 	sc = carp_ifp->if_softc;
2168 
2169 	/* Set the source MAC address to Virtual Router MAC Address */
2170 	switch (ifp->if_type) {
2171 	case IFT_ETHER:
2172 	case IFT_L2VLAN: {
2173 			struct ether_header *eh;
2174 
2175 			eh = mtod(m, struct ether_header *);
2176 			eh->ether_shost[0] = 0;
2177 			eh->ether_shost[1] = 0;
2178 			eh->ether_shost[2] = 0x5e;
2179 			eh->ether_shost[3] = 0;
2180 			eh->ether_shost[4] = 1;
2181 			eh->ether_shost[5] = sc->sc_vhid;
2182 		}
2183 		break;
2184 	case IFT_FDDI: {
2185 			struct fddi_header *fh;
2186 
2187 			fh = mtod(m, struct fddi_header *);
2188 			fh->fddi_shost[0] = 0;
2189 			fh->fddi_shost[1] = 0;
2190 			fh->fddi_shost[2] = 0x5e;
2191 			fh->fddi_shost[3] = 0;
2192 			fh->fddi_shost[4] = 1;
2193 			fh->fddi_shost[5] = sc->sc_vhid;
2194 		}
2195 		break;
2196 	case IFT_ISO88025: {
2197  			struct iso88025_header *th;
2198  			th = mtod(m, struct iso88025_header *);
2199 			th->iso88025_shost[0] = 3;
2200 			th->iso88025_shost[1] = 0;
2201 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
2202 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
2203 			th->iso88025_shost[4] = 0;
2204 			th->iso88025_shost[5] = 0;
2205 		}
2206 		break;
2207 	default:
2208 		printf("%s: carp is not supported for this interface type\n",
2209 		    ifp->if_xname);
2210 		return (EOPNOTSUPP);
2211 	}
2212 
2213 	return (0);
2214 }
2215 
2216 static void
2217 carp_set_state(struct carp_softc *sc, int state)
2218 {
2219 	int link_state;
2220 
2221 	if (sc->sc_carpdev)
2222 		CARP_SCLOCK_ASSERT(sc);
2223 
2224 	if (sc->sc_state == state)
2225 		return;
2226 
2227 	sc->sc_state = state;
2228 	switch (state) {
2229 	case BACKUP:
2230 		link_state = LINK_STATE_DOWN;
2231 		break;
2232 	case MASTER:
2233 		link_state = LINK_STATE_UP;
2234 		break;
2235 	default:
2236 		link_state = LINK_STATE_UNKNOWN;
2237 		break;
2238 	}
2239 	if_link_state_change(SC2IFP(sc), link_state);
2240 }
2241 
2242 void
2243 carp_carpdev_state(struct ifnet *ifp)
2244 {
2245 	struct carp_if *cif;
2246 
2247 	cif = ifp->if_carp;
2248 	CARP_LOCK(cif);
2249 	carp_carpdev_state_locked(cif);
2250 	CARP_UNLOCK(cif);
2251 }
2252 
2253 static void
2254 carp_carpdev_state_locked(struct carp_if *cif)
2255 {
2256 	struct carp_softc *sc;
2257 
2258 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list)
2259 		carp_sc_state_locked(sc);
2260 }
2261 
2262 static void
2263 carp_sc_state_locked(struct carp_softc *sc)
2264 {
2265 	CARP_SCLOCK_ASSERT(sc);
2266 
2267 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2268 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
2269 		sc->sc_flags_backup = SC2IFP(sc)->if_flags;
2270 		SC2IFP(sc)->if_flags &= ~IFF_UP;
2271 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
2272 		callout_stop(&sc->sc_ad_tmo);
2273 		callout_stop(&sc->sc_md_tmo);
2274 		callout_stop(&sc->sc_md6_tmo);
2275 		carp_set_state(sc, INIT);
2276 		carp_setrun(sc, 0);
2277 		if (!sc->sc_suppress) {
2278 			carp_suppress_preempt++;
2279 			if (carp_suppress_preempt == 1) {
2280 				CARP_SCUNLOCK(sc);
2281 				carp_send_ad_all();
2282 				CARP_SCLOCK(sc);
2283 			}
2284 		}
2285 		sc->sc_suppress = 1;
2286 	} else {
2287 		SC2IFP(sc)->if_flags |= sc->sc_flags_backup;
2288 		carp_set_state(sc, INIT);
2289 		carp_setrun(sc, 0);
2290 		if (sc->sc_suppress)
2291 			carp_suppress_preempt--;
2292 		sc->sc_suppress = 0;
2293 	}
2294 
2295 	return;
2296 }
2297 
2298 #ifdef INET
2299 extern  struct domain inetdomain;
2300 static struct protosw in_carp_protosw = {
2301 	.pr_type =		SOCK_RAW,
2302 	.pr_domain =		&inetdomain,
2303 	.pr_protocol =		IPPROTO_CARP,
2304 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2305 	.pr_input =		carp_input,
2306 	.pr_output =		(pr_output_t *)rip_output,
2307 	.pr_ctloutput =		rip_ctloutput,
2308 	.pr_usrreqs =		&rip_usrreqs
2309 };
2310 #endif
2311 
2312 #ifdef INET6
2313 extern	struct domain inet6domain;
2314 static struct ip6protosw in6_carp_protosw = {
2315 	.pr_type =		SOCK_RAW,
2316 	.pr_domain =		&inet6domain,
2317 	.pr_protocol =		IPPROTO_CARP,
2318 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2319 	.pr_input =		carp6_input,
2320 	.pr_output =		rip6_output,
2321 	.pr_ctloutput =		rip6_ctloutput,
2322 	.pr_usrreqs =		&rip6_usrreqs
2323 };
2324 #endif
2325 
2326 static void
2327 carp_mod_cleanup(void)
2328 {
2329 
2330 	if (if_detach_event_tag == NULL)
2331 		return;
2332 	EVENTHANDLER_DEREGISTER(ifnet_departure_event, if_detach_event_tag);
2333 	if_clone_detach(&carp_cloner);
2334 #ifdef INET
2335 	if (proto_reg[CARP_INET] == 0) {
2336 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2337 		proto_reg[CARP_INET] = -1;
2338 	}
2339 	carp_iamatch_p = NULL;
2340 #endif
2341 #ifdef INET6
2342 	if (proto_reg[CARP_INET6] == 0) {
2343 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2344 		proto_reg[CARP_INET6] = -1;
2345 	}
2346 	carp_iamatch6_p = NULL;
2347 	carp_macmatch6_p = NULL;
2348 #endif
2349 	carp_linkstate_p = NULL;
2350 	carp_forus_p = NULL;
2351 	carp_output_p = NULL;
2352 	mtx_destroy(&carp_mtx);
2353 }
2354 
2355 static int
2356 carp_mod_load(void)
2357 {
2358 
2359 	if_detach_event_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
2360 		carp_ifdetach, NULL, EVENTHANDLER_PRI_ANY);
2361 	if (if_detach_event_tag == NULL)
2362 		return (ENOMEM);
2363 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2364 	LIST_INIT(&carpif_list);
2365 	if_clone_attach(&carp_cloner);
2366 	carp_linkstate_p = carp_carpdev_state;
2367 	carp_forus_p = carp_forus;
2368 	carp_output_p = carp_output;
2369 #ifdef INET6
2370 	carp_iamatch6_p = carp_iamatch6;
2371 	carp_macmatch6_p = carp_macmatch6;
2372 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2373 	    (struct protosw *)&in6_carp_protosw);
2374 	if (proto_reg[CARP_INET6] != 0) {
2375 		printf("carp: error %d attaching to PF_INET6\n",
2376 		    proto_reg[CARP_INET6]);
2377 		carp_mod_cleanup();
2378 		return (EINVAL);
2379 	}
2380 #endif
2381 #ifdef INET
2382 	carp_iamatch_p = carp_iamatch;
2383 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2384 	if (proto_reg[CARP_INET] != 0) {
2385 		printf("carp: error %d attaching to PF_INET\n",
2386 		    proto_reg[CARP_INET]);
2387 		carp_mod_cleanup();
2388 		return (EINVAL);
2389 	}
2390 #endif
2391 	return 0;
2392 }
2393 
2394 static int
2395 carp_modevent(module_t mod, int type, void *data)
2396 {
2397 	switch (type) {
2398 	case MOD_LOAD:
2399 		return carp_mod_load();
2400 		/* NOTREACHED */
2401 	case MOD_UNLOAD:
2402 		/*
2403 		 * XXX: For now, disallow module unloading by default due to
2404 		 * a race condition where a thread may dereference one of the
2405 		 * function pointer hooks after the module has been
2406 		 * unloaded, during processing of a packet, causing a panic.
2407 		 */
2408 #ifdef CARPMOD_CAN_UNLOAD
2409 		carp_mod_cleanup();
2410 #else
2411 		return (EBUSY);
2412 #endif
2413 		break;
2414 
2415 	default:
2416 		return (EINVAL);
2417 	}
2418 
2419 	return (0);
2420 }
2421 
2422 static moduledata_t carp_mod = {
2423 	"carp",
2424 	carp_modevent,
2425 	0
2426 };
2427 
2428 DECLARE_MODULE(carp, carp_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
2429