xref: /freebsd/sys/netinet/ip_carp.c (revision 830940567b49bb0c08dfaed40418999e76616909)
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_carp.h"
31 #include "opt_bpf.h"
32 #include "opt_inet.h"
33 #include "opt_inet6.h"
34 
35 #include <sys/types.h>
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/conf.h>
39 #include <sys/kernel.h>
40 #include <sys/limits.h>
41 #include <sys/malloc.h>
42 #include <sys/mbuf.h>
43 #include <sys/module.h>
44 #include <sys/time.h>
45 #include <sys/priv.h>
46 #include <sys/proc.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/ip6_var.h>
83 #include <netinet6/scope6_var.h>
84 #include <netinet6/nd6.h>
85 #endif
86 
87 #include <crypto/sha1.h>
88 #include <netinet/ip_carp.h>
89 
90 #define	CARP_IFNAME	"carp"
91 static MALLOC_DEFINE(M_CARP, "CARP", "CARP interfaces");
92 SYSCTL_DECL(_net_inet_carp);
93 
94 struct carp_softc {
95 	struct ifnet	 	*sc_ifp;	/* Interface clue */
96 	struct ifnet		*sc_carpdev;	/* Pointer to parent interface */
97 	struct in_ifaddr 	*sc_ia;		/* primary iface address */
98 	struct ip_moptions 	 sc_imo;
99 #ifdef INET6
100 	struct in6_ifaddr 	*sc_ia6;	/* primary iface address v6 */
101 	struct ip6_moptions 	 sc_im6o;
102 #endif /* INET6 */
103 	TAILQ_ENTRY(carp_softc)	 sc_list;
104 
105 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
106 
107 	int			 sc_flags_backup;
108 	int			 sc_suppress;
109 
110 	int			 sc_sendad_errors;
111 #define	CARP_SENDAD_MAX_ERRORS	3
112 	int			 sc_sendad_success;
113 #define	CARP_SENDAD_MIN_SUCCESS 3
114 
115 	int			 sc_vhid;
116 	int			 sc_advskew;
117 	int			 sc_naddrs;
118 	int			 sc_naddrs6;
119 	int			 sc_advbase;	/* seconds */
120 	int			 sc_init_counter;
121 	u_int64_t		 sc_counter;
122 
123 	/* authentication */
124 #define CARP_HMAC_PAD	64
125 	unsigned char sc_key[CARP_KEY_LEN];
126 	unsigned char sc_pad[CARP_HMAC_PAD];
127 	SHA1_CTX sc_sha1;
128 
129 	struct callout		 sc_ad_tmo;	/* advertisement timeout */
130 	struct callout		 sc_md_tmo;	/* master down timeout */
131 	struct callout 		 sc_md6_tmo;	/* master down timeout */
132 
133 	LIST_ENTRY(carp_softc)	 sc_next;	/* Interface clue */
134 };
135 #define	SC2IFP(sc)	((sc)->sc_ifp)
136 
137 int carp_suppress_preempt = 0;
138 int carp_opts[CARPCTL_MAXID] = { 0, 1, 0, 1, 0, 0 };	/* XXX for now */
139 SYSCTL_INT(_net_inet_carp, CARPCTL_ALLOW, allow, CTLFLAG_RW,
140     &carp_opts[CARPCTL_ALLOW], 0, "Accept incoming CARP packets");
141 SYSCTL_INT(_net_inet_carp, CARPCTL_PREEMPT, preempt, CTLFLAG_RW,
142     &carp_opts[CARPCTL_PREEMPT], 0, "high-priority backup preemption mode");
143 SYSCTL_INT(_net_inet_carp, CARPCTL_LOG, log, CTLFLAG_RW,
144     &carp_opts[CARPCTL_LOG], 0, "log bad carp packets");
145 SYSCTL_INT(_net_inet_carp, CARPCTL_ARPBALANCE, arpbalance, CTLFLAG_RW,
146     &carp_opts[CARPCTL_ARPBALANCE], 0, "balance arp responses");
147 SYSCTL_INT(_net_inet_carp, OID_AUTO, suppress_preempt, CTLFLAG_RD,
148     &carp_suppress_preempt, 0, "Preemption is suppressed");
149 
150 struct carpstats carpstats;
151 SYSCTL_STRUCT(_net_inet_carp, CARPCTL_STATS, stats, CTLFLAG_RW,
152     &carpstats, carpstats,
153     "CARP statistics (struct carpstats, netinet/ip_carp.h)");
154 
155 struct carp_if {
156 	TAILQ_HEAD(, carp_softc) vhif_vrs;
157 	int vhif_nvrs;
158 
159 	struct ifnet 	*vhif_ifp;
160 	struct mtx	 vhif_mtx;
161 };
162 
163 /* Get carp_if from softc. Valid after carp_set_addr{,6}. */
164 #define	SC2CIF(sc)		((struct carp_if *)(sc)->sc_carpdev->if_carp)
165 
166 /* lock per carp_if queue */
167 #define	CARP_LOCK_INIT(cif)	mtx_init(&(cif)->vhif_mtx, "carp_if", 	\
168 	NULL, MTX_DEF)
169 #define	CARP_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->vhif_mtx)
170 #define	CARP_LOCK_ASSERT(cif)	mtx_assert(&(cif)->vhif_mtx, MA_OWNED)
171 #define	CARP_LOCK(cif)		mtx_lock(&(cif)->vhif_mtx)
172 #define	CARP_UNLOCK(cif)	mtx_unlock(&(cif)->vhif_mtx)
173 
174 #define	CARP_SCLOCK(sc)		mtx_lock(&SC2CIF(sc)->vhif_mtx)
175 #define	CARP_SCUNLOCK(sc)	mtx_unlock(&SC2CIF(sc)->vhif_mtx)
176 #define	CARP_SCLOCK_ASSERT(sc)	mtx_assert(&SC2CIF(sc)->vhif_mtx, MA_OWNED)
177 
178 #define	CARP_LOG(...)	do {				\
179 	if (carp_opts[CARPCTL_LOG] > 0)			\
180 		log(LOG_INFO, __VA_ARGS__);		\
181 } while (0)
182 
183 #define	CARP_DEBUG(...)	do {				\
184 	if (carp_opts[CARPCTL_LOG] > 1)			\
185 		log(LOG_DEBUG, __VA_ARGS__);		\
186 } while (0)
187 
188 static void	carp_hmac_prepare(struct carp_softc *);
189 static void	carp_hmac_generate(struct carp_softc *, u_int32_t *,
190 		    unsigned char *);
191 static int	carp_hmac_verify(struct carp_softc *, u_int32_t *,
192 		    unsigned char *);
193 static void	carp_setroute(struct carp_softc *, int);
194 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
195 static int 	carp_clone_create(struct if_clone *, int, caddr_t);
196 static void 	carp_clone_destroy(struct ifnet *);
197 static void	carpdetach(struct carp_softc *, int);
198 static int	carp_prepare_ad(struct mbuf *, struct carp_softc *,
199 		    struct carp_header *);
200 static void	carp_send_ad_all(void);
201 static void	carp_send_ad(void *);
202 static void	carp_send_ad_locked(struct carp_softc *);
203 static void	carp_send_arp(struct carp_softc *);
204 static void	carp_master_down(void *);
205 static void	carp_master_down_locked(struct carp_softc *);
206 static int	carp_ioctl(struct ifnet *, u_long, caddr_t);
207 static int	carp_looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
208     		    struct route *);
209 static void	carp_start(struct ifnet *);
210 static void	carp_setrun(struct carp_softc *, sa_family_t);
211 static void	carp_set_state(struct carp_softc *, int);
212 static int	carp_addrcount(struct carp_if *, struct in_ifaddr *, int);
213 enum	{ CARP_COUNT_MASTER, CARP_COUNT_RUNNING };
214 
215 static void	carp_multicast_cleanup(struct carp_softc *);
216 static int	carp_set_addr(struct carp_softc *, struct sockaddr_in *);
217 static int	carp_del_addr(struct carp_softc *, struct sockaddr_in *);
218 static void	carp_carpdev_state_locked(struct carp_if *);
219 static void	carp_sc_state_locked(struct carp_softc *);
220 #ifdef INET6
221 static void	carp_send_na(struct carp_softc *);
222 static int	carp_set_addr6(struct carp_softc *, struct sockaddr_in6 *);
223 static int	carp_del_addr6(struct carp_softc *, struct sockaddr_in6 *);
224 static void	carp_multicast6_cleanup(struct carp_softc *);
225 #endif
226 
227 static LIST_HEAD(, carp_softc) carpif_list;
228 static struct mtx carp_mtx;
229 IFC_SIMPLE_DECLARE(carp, 0);
230 
231 static eventhandler_tag if_detach_event_tag;
232 
233 static __inline u_int16_t
234 carp_cksum(struct mbuf *m, int len)
235 {
236 	return (in_cksum(m, len));
237 }
238 
239 static void
240 carp_hmac_prepare(struct carp_softc *sc)
241 {
242 	u_int8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
243 	u_int8_t vhid = sc->sc_vhid & 0xff;
244 	struct ifaddr *ifa;
245 	int i, found;
246 #ifdef INET
247 	struct in_addr last, cur, in;
248 #endif
249 #ifdef INET6
250 	struct in6_addr last6, cur6, in6;
251 #endif
252 
253 	if (sc->sc_carpdev)
254 		CARP_SCLOCK(sc);
255 
256 	/* XXX: possible race here */
257 
258 	/* compute ipad from key */
259 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
260 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
261 	for (i = 0; i < sizeof(sc->sc_pad); i++)
262 		sc->sc_pad[i] ^= 0x36;
263 
264 	/* precompute first part of inner hash */
265 	SHA1Init(&sc->sc_sha1);
266 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
267 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
268 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
269 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
270 #ifdef INET
271 	cur.s_addr = 0;
272 	do {
273 		found = 0;
274 		last = cur;
275 		cur.s_addr = 0xffffffff;
276 		IF_ADDR_LOCK(SC2IFP(sc));
277 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
278 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
279 			if (ifa->ifa_addr->sa_family == AF_INET &&
280 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
281 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
282 				cur.s_addr = in.s_addr;
283 				found++;
284 			}
285 		}
286 		IF_ADDR_UNLOCK(SC2IFP(sc));
287 		if (found)
288 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
289 	} while (found);
290 #endif /* INET */
291 #ifdef INET6
292 	memset(&cur6, 0, sizeof(cur6));
293 	do {
294 		found = 0;
295 		last6 = cur6;
296 		memset(&cur6, 0xff, sizeof(cur6));
297 		IF_ADDR_LOCK(SC2IFP(sc));
298 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
299 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
300 			if (IN6_IS_SCOPE_EMBED(&in6))
301 				in6.s6_addr16[1] = 0;
302 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
303 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
304 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
305 				cur6 = in6;
306 				found++;
307 			}
308 		}
309 		IF_ADDR_UNLOCK(SC2IFP(sc));
310 		if (found)
311 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
312 	} while (found);
313 #endif /* INET6 */
314 
315 	/* convert ipad to opad */
316 	for (i = 0; i < sizeof(sc->sc_pad); i++)
317 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
318 
319 	if (sc->sc_carpdev)
320 		CARP_SCUNLOCK(sc);
321 }
322 
323 static void
324 carp_hmac_generate(struct carp_softc *sc, u_int32_t counter[2],
325     unsigned char md[20])
326 {
327 	SHA1_CTX sha1ctx;
328 
329 	/* fetch first half of inner hash */
330 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
331 
332 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
333 	SHA1Final(md, &sha1ctx);
334 
335 	/* outer hash */
336 	SHA1Init(&sha1ctx);
337 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
338 	SHA1Update(&sha1ctx, md, 20);
339 	SHA1Final(md, &sha1ctx);
340 }
341 
342 static int
343 carp_hmac_verify(struct carp_softc *sc, u_int32_t counter[2],
344     unsigned char md[20])
345 {
346 	unsigned char md2[20];
347 
348 	CARP_SCLOCK_ASSERT(sc);
349 
350 	carp_hmac_generate(sc, counter, md2);
351 
352 	return (bcmp(md, md2, sizeof(md2)));
353 }
354 
355 static void
356 carp_setroute(struct carp_softc *sc, int cmd)
357 {
358 	struct ifaddr *ifa;
359 	int s;
360 
361 	if (sc->sc_carpdev)
362 		CARP_SCLOCK_ASSERT(sc);
363 
364 	s = splnet();
365 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
366 		if (ifa->ifa_addr->sa_family == AF_INET &&
367 		    sc->sc_carpdev != NULL) {
368 			int count = carp_addrcount(
369 			    (struct carp_if *)sc->sc_carpdev->if_carp,
370 			    ifatoia(ifa), CARP_COUNT_MASTER);
371 
372 			if ((cmd == RTM_ADD && count == 1) ||
373 			    (cmd == RTM_DELETE && count == 0))
374 				rtinit(ifa, cmd, RTF_UP | RTF_HOST);
375 		}
376 	}
377 	splx(s);
378 }
379 
380 static int
381 carp_clone_create(struct if_clone *ifc, int unit, caddr_t params)
382 {
383 
384 	struct carp_softc *sc;
385 	struct ifnet *ifp;
386 
387 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
388 	ifp = SC2IFP(sc) = if_alloc(IFT_ETHER);
389 	if (ifp == NULL) {
390 		free(sc, M_CARP);
391 		return (ENOSPC);
392 	}
393 
394 	sc->sc_flags_backup = 0;
395 	sc->sc_suppress = 0;
396 	sc->sc_advbase = CARP_DFLTINTV;
397 	sc->sc_vhid = -1;	/* required setting */
398 	sc->sc_advskew = 0;
399 	sc->sc_init_counter = 1;
400 	sc->sc_naddrs = sc->sc_naddrs6 = 0; /* M_ZERO? */
401 	sc->sc_imo.imo_membership = (struct in_multi **)malloc(
402 	    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
403 	    M_WAITOK);
404 	sc->sc_imo.imo_mfilters = NULL;
405 	sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
406 	sc->sc_imo.imo_multicast_vif = -1;
407 #ifdef INET6
408 	sc->sc_im6o.im6o_membership = (struct in6_multi **)malloc(
409 	    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
410 	    M_WAITOK);
411 	sc->sc_im6o.im6o_mfilters = NULL;
412 	sc->sc_im6o.im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
413 	sc->sc_im6o.im6o_multicast_hlim = CARP_DFLTTL;
414 #endif
415 
416 	callout_init(&sc->sc_ad_tmo, CALLOUT_MPSAFE);
417 	callout_init(&sc->sc_md_tmo, CALLOUT_MPSAFE);
418 	callout_init(&sc->sc_md6_tmo, CALLOUT_MPSAFE);
419 
420 	ifp->if_softc = sc;
421 	if_initname(ifp, CARP_IFNAME, unit);
422 	ifp->if_mtu = ETHERMTU;
423 	ifp->if_flags = IFF_LOOPBACK;
424 	ifp->if_ioctl = carp_ioctl;
425 	ifp->if_output = carp_looutput;
426 	ifp->if_start = carp_start;
427 	ifp->if_type = IFT_CARP;
428 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
429 	ifp->if_hdrlen = 0;
430 	if_attach(ifp);
431 	bpfattach(SC2IFP(sc), DLT_NULL, sizeof(u_int32_t));
432 	mtx_lock(&carp_mtx);
433 	LIST_INSERT_HEAD(&carpif_list, sc, sc_next);
434 	mtx_unlock(&carp_mtx);
435 	return (0);
436 }
437 
438 static void
439 carp_clone_destroy(struct ifnet *ifp)
440 {
441 	struct carp_softc *sc = ifp->if_softc;
442 
443 	if (sc->sc_carpdev)
444 		CARP_SCLOCK(sc);
445 	carpdetach(sc, 1);	/* Returns unlocked. */
446 
447 	mtx_lock(&carp_mtx);
448 	LIST_REMOVE(sc, sc_next);
449 	mtx_unlock(&carp_mtx);
450 	bpfdetach(ifp);
451 	if_detach(ifp);
452 	if_free_type(ifp, IFT_ETHER);
453 	free(sc->sc_imo.imo_membership, M_CARP);
454 #ifdef INET6
455 	free(sc->sc_im6o.im6o_membership, M_CARP);
456 #endif
457 	free(sc, M_CARP);
458 }
459 
460 /*
461  * This function can be called on CARP interface destroy path,
462  * and in case of the removal of the underlying interface as
463  * well. We differentiate these two cases. In the latter case
464  * we do not cleanup our multicast memberships, since they
465  * are already freed. Also, in the latter case we do not
466  * release the lock on return, because the function will be
467  * called once more, for another CARP instance on the same
468  * interface.
469  */
470 static void
471 carpdetach(struct carp_softc *sc, int unlock)
472 {
473 	struct carp_if *cif;
474 
475 	callout_stop(&sc->sc_ad_tmo);
476 	callout_stop(&sc->sc_md_tmo);
477 	callout_stop(&sc->sc_md6_tmo);
478 
479 	if (sc->sc_suppress)
480 		carp_suppress_preempt--;
481 	sc->sc_suppress = 0;
482 
483 	if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS)
484 		carp_suppress_preempt--;
485 	sc->sc_sendad_errors = 0;
486 
487 	carp_set_state(sc, INIT);
488 	SC2IFP(sc)->if_flags &= ~IFF_UP;
489 	carp_setrun(sc, 0);
490 	if (unlock)
491 		carp_multicast_cleanup(sc);
492 #ifdef INET6
493 	carp_multicast6_cleanup(sc);
494 #endif
495 
496 	if (sc->sc_carpdev != NULL) {
497 		cif = (struct carp_if *)sc->sc_carpdev->if_carp;
498 		CARP_LOCK_ASSERT(cif);
499 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
500 		if (!--cif->vhif_nvrs) {
501 			ifpromisc(sc->sc_carpdev, 0);
502 			sc->sc_carpdev->if_carp = NULL;
503 			CARP_LOCK_DESTROY(cif);
504 			free(cif, M_IFADDR);
505 		} else if (unlock)
506 			CARP_UNLOCK(cif);
507 		sc->sc_carpdev = NULL;
508 	}
509 }
510 
511 /* Detach an interface from the carp. */
512 static void
513 carp_ifdetach(void *arg __unused, struct ifnet *ifp)
514 {
515 	struct carp_if *cif = (struct carp_if *)ifp->if_carp;
516 	struct carp_softc *sc, *nextsc;
517 
518 	if (cif == NULL)
519 		return;
520 
521 	/*
522 	 * XXX: At the end of for() cycle the lock will be destroyed.
523 	 */
524 	CARP_LOCK(cif);
525 	for (sc = TAILQ_FIRST(&cif->vhif_vrs); sc; sc = nextsc) {
526 		nextsc = TAILQ_NEXT(sc, sc_list);
527 		carpdetach(sc, 0);
528 	}
529 }
530 
531 /*
532  * process input packet.
533  * we have rearranged checks order compared to the rfc,
534  * but it seems more efficient this way or not possible otherwise.
535  */
536 void
537 carp_input(struct mbuf *m, int hlen)
538 {
539 	struct ip *ip = mtod(m, struct ip *);
540 	struct carp_header *ch;
541 	int iplen, len;
542 
543 	CARPSTATS_INC(carps_ipackets);
544 
545 	if (!carp_opts[CARPCTL_ALLOW]) {
546 		m_freem(m);
547 		return;
548 	}
549 
550 	/* check if received on a valid carp interface */
551 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
552 		CARPSTATS_INC(carps_badif);
553 		CARP_LOG("carp_input: packet received on non-carp "
554 		    "interface: %s\n",
555 		    m->m_pkthdr.rcvif->if_xname);
556 		m_freem(m);
557 		return;
558 	}
559 
560 	/* verify that the IP TTL is 255.  */
561 	if (ip->ip_ttl != CARP_DFLTTL) {
562 		CARPSTATS_INC(carps_badttl);
563 		CARP_LOG("carp_input: received ttl %d != 255i on %s\n",
564 		    ip->ip_ttl,
565 		    m->m_pkthdr.rcvif->if_xname);
566 		m_freem(m);
567 		return;
568 	}
569 
570 	iplen = ip->ip_hl << 2;
571 
572 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
573 		CARPSTATS_INC(carps_badlen);
574 		CARP_LOG("carp_input: received len %zd < "
575 		    "sizeof(struct carp_header) on %s\n",
576 		    m->m_len - sizeof(struct ip),
577 		    m->m_pkthdr.rcvif->if_xname);
578 		m_freem(m);
579 		return;
580 	}
581 
582 	if (iplen + sizeof(*ch) < m->m_len) {
583 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
584 			CARPSTATS_INC(carps_hdrops);
585 			CARP_LOG("carp_input: pullup failed\n");
586 			return;
587 		}
588 		ip = mtod(m, struct ip *);
589 	}
590 	ch = (struct carp_header *)((char *)ip + iplen);
591 
592 	/*
593 	 * verify that the received packet length is
594 	 * equal to the CARP header
595 	 */
596 	len = iplen + sizeof(*ch);
597 	if (len > m->m_pkthdr.len) {
598 		CARPSTATS_INC(carps_badlen);
599 		CARP_LOG("carp_input: packet too short %d on %s\n",
600 		    m->m_pkthdr.len,
601 		    m->m_pkthdr.rcvif->if_xname);
602 		m_freem(m);
603 		return;
604 	}
605 
606 	if ((m = m_pullup(m, len)) == NULL) {
607 		CARPSTATS_INC(carps_hdrops);
608 		return;
609 	}
610 	ip = mtod(m, struct ip *);
611 	ch = (struct carp_header *)((char *)ip + iplen);
612 
613 	/* verify the CARP checksum */
614 	m->m_data += iplen;
615 	if (carp_cksum(m, len - iplen)) {
616 		CARPSTATS_INC(carps_badsum);
617 		CARP_LOG("carp_input: checksum failed on %s\n",
618 		    m->m_pkthdr.rcvif->if_xname);
619 		m_freem(m);
620 		return;
621 	}
622 	m->m_data -= iplen;
623 
624 	carp_input_c(m, ch, AF_INET);
625 }
626 
627 #ifdef INET6
628 int
629 carp6_input(struct mbuf **mp, int *offp, int proto)
630 {
631 	struct mbuf *m = *mp;
632 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
633 	struct carp_header *ch;
634 	u_int len;
635 
636 	CARPSTATS_INC(carps_ipackets6);
637 
638 	if (!carp_opts[CARPCTL_ALLOW]) {
639 		m_freem(m);
640 		return (IPPROTO_DONE);
641 	}
642 
643 	/* check if received on a valid carp interface */
644 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
645 		CARPSTATS_INC(carps_badif);
646 		CARP_LOG("carp6_input: packet received on non-carp "
647 		    "interface: %s\n",
648 		    m->m_pkthdr.rcvif->if_xname);
649 		m_freem(m);
650 		return (IPPROTO_DONE);
651 	}
652 
653 	/* verify that the IP TTL is 255 */
654 	if (ip6->ip6_hlim != CARP_DFLTTL) {
655 		CARPSTATS_INC(carps_badttl);
656 		CARP_LOG("carp6_input: received ttl %d != 255 on %s\n",
657 		    ip6->ip6_hlim,
658 		    m->m_pkthdr.rcvif->if_xname);
659 		m_freem(m);
660 		return (IPPROTO_DONE);
661 	}
662 
663 	/* verify that we have a complete carp packet */
664 	len = m->m_len;
665 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
666 	if (ch == NULL) {
667 		CARPSTATS_INC(carps_badlen);
668 		CARP_LOG("carp6_input: packet size %u too small\n", len);
669 		return (IPPROTO_DONE);
670 	}
671 
672 
673 	/* verify the CARP checksum */
674 	m->m_data += *offp;
675 	if (carp_cksum(m, sizeof(*ch))) {
676 		CARPSTATS_INC(carps_badsum);
677 		CARP_LOG("carp6_input: checksum failed, on %s\n",
678 		    m->m_pkthdr.rcvif->if_xname);
679 		m_freem(m);
680 		return (IPPROTO_DONE);
681 	}
682 	m->m_data -= *offp;
683 
684 	carp_input_c(m, ch, AF_INET6);
685 	return (IPPROTO_DONE);
686 }
687 #endif /* INET6 */
688 
689 static void
690 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
691 {
692 	struct ifnet *ifp = m->m_pkthdr.rcvif;
693 	struct carp_softc *sc;
694 	u_int64_t tmp_counter;
695 	struct timeval sc_tv, ch_tv;
696 
697 	/* verify that the VHID is valid on the receiving interface */
698 	CARP_LOCK(ifp->if_carp);
699 	TAILQ_FOREACH(sc, &((struct carp_if *)ifp->if_carp)->vhif_vrs, sc_list)
700 		if (sc->sc_vhid == ch->carp_vhid)
701 			break;
702 
703 	if (!sc || !((SC2IFP(sc)->if_flags & IFF_UP) &&
704 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
705 		CARPSTATS_INC(carps_badvhid);
706 		CARP_UNLOCK(ifp->if_carp);
707 		m_freem(m);
708 		return;
709 	}
710 
711 	getmicrotime(&SC2IFP(sc)->if_lastchange);
712 	SC2IFP(sc)->if_ipackets++;
713 	SC2IFP(sc)->if_ibytes += m->m_pkthdr.len;
714 
715 	if (bpf_peers_present(SC2IFP(sc)->if_bpf)) {
716 		struct ip *ip = mtod(m, struct ip *);
717 		uint32_t af1 = af;
718 
719 		/* BPF wants net byte order */
720 		ip->ip_len = htons(ip->ip_len + (ip->ip_hl << 2));
721 		ip->ip_off = htons(ip->ip_off);
722 		bpf_mtap2(SC2IFP(sc)->if_bpf, &af1, sizeof(af1), m);
723 	}
724 
725 	/* verify the CARP version. */
726 	if (ch->carp_version != CARP_VERSION) {
727 		CARPSTATS_INC(carps_badver);
728 		SC2IFP(sc)->if_ierrors++;
729 		CARP_UNLOCK(ifp->if_carp);
730 		CARP_LOG("%s; invalid version %d\n",
731 		    SC2IFP(sc)->if_xname,
732 		    ch->carp_version);
733 		m_freem(m);
734 		return;
735 	}
736 
737 	/* verify the hash */
738 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
739 		CARPSTATS_INC(carps_badauth);
740 		SC2IFP(sc)->if_ierrors++;
741 		CARP_UNLOCK(ifp->if_carp);
742 		CARP_LOG("%s: incorrect hash\n", SC2IFP(sc)->if_xname);
743 		m_freem(m);
744 		return;
745 	}
746 
747 	tmp_counter = ntohl(ch->carp_counter[0]);
748 	tmp_counter = tmp_counter<<32;
749 	tmp_counter += ntohl(ch->carp_counter[1]);
750 
751 	/* XXX Replay protection goes here */
752 
753 	sc->sc_init_counter = 0;
754 	sc->sc_counter = tmp_counter;
755 
756 	sc_tv.tv_sec = sc->sc_advbase;
757 	if (carp_suppress_preempt && sc->sc_advskew <  240)
758 		sc_tv.tv_usec = 240 * 1000000 / 256;
759 	else
760 		sc_tv.tv_usec = sc->sc_advskew * 1000000 / 256;
761 	ch_tv.tv_sec = ch->carp_advbase;
762 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
763 
764 	switch (sc->sc_state) {
765 	case INIT:
766 		break;
767 	case MASTER:
768 		/*
769 		 * If we receive an advertisement from a master who's going to
770 		 * be more frequent than us, go into BACKUP state.
771 		 */
772 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
773 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
774 			callout_stop(&sc->sc_ad_tmo);
775 			CARP_DEBUG("%s: MASTER -> BACKUP "
776 			   "(more frequent advertisement received)\n",
777 			   SC2IFP(sc)->if_xname);
778 			carp_set_state(sc, BACKUP);
779 			carp_setrun(sc, 0);
780 			carp_setroute(sc, RTM_DELETE);
781 		}
782 		break;
783 	case BACKUP:
784 		/*
785 		 * If we're pre-empting masters who advertise slower than us,
786 		 * and this one claims to be slower, treat him as down.
787 		 */
788 		if (carp_opts[CARPCTL_PREEMPT] &&
789 		    timevalcmp(&sc_tv, &ch_tv, <)) {
790 			CARP_DEBUG("%s: BACKUP -> MASTER "
791 			    "(preempting a slower master)\n",
792 			    SC2IFP(sc)->if_xname);
793 			carp_master_down_locked(sc);
794 			break;
795 		}
796 
797 		/*
798 		 *  If the master is going to advertise at such a low frequency
799 		 *  that he's guaranteed to time out, we'd might as well just
800 		 *  treat him as timed out now.
801 		 */
802 		sc_tv.tv_sec = sc->sc_advbase * 3;
803 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
804 			CARP_DEBUG("%s: BACKUP -> MASTER "
805 			    "(master timed out)\n",
806 			    SC2IFP(sc)->if_xname);
807 			carp_master_down_locked(sc);
808 			break;
809 		}
810 
811 		/*
812 		 * Otherwise, we reset the counter and wait for the next
813 		 * advertisement.
814 		 */
815 		carp_setrun(sc, af);
816 		break;
817 	}
818 
819 	CARP_UNLOCK(ifp->if_carp);
820 
821 	m_freem(m);
822 	return;
823 }
824 
825 static int
826 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
827 {
828 	struct m_tag *mtag;
829 	struct ifnet *ifp = SC2IFP(sc);
830 
831 	if (sc->sc_init_counter) {
832 		/* this could also be seconds since unix epoch */
833 		sc->sc_counter = arc4random();
834 		sc->sc_counter = sc->sc_counter << 32;
835 		sc->sc_counter += arc4random();
836 	} else
837 		sc->sc_counter++;
838 
839 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
840 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
841 
842 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
843 
844 	/* Tag packet for carp_output */
845 	mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct ifnet *), M_NOWAIT);
846 	if (mtag == NULL) {
847 		m_freem(m);
848 		SC2IFP(sc)->if_oerrors++;
849 		return (ENOMEM);
850 	}
851 	bcopy(&ifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *));
852 	m_tag_prepend(m, mtag);
853 
854 	return (0);
855 }
856 
857 static void
858 carp_send_ad_all(void)
859 {
860 	struct carp_softc *sc;
861 
862 	mtx_lock(&carp_mtx);
863 	LIST_FOREACH(sc, &carpif_list, sc_next) {
864 		if (sc->sc_carpdev == NULL)
865 			continue;
866 		CARP_SCLOCK(sc);
867 		if ((SC2IFP(sc)->if_flags & IFF_UP) &&
868 		    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING) &&
869 		     sc->sc_state == MASTER)
870 			carp_send_ad_locked(sc);
871 		CARP_SCUNLOCK(sc);
872 	}
873 	mtx_unlock(&carp_mtx);
874 }
875 
876 static void
877 carp_send_ad(void *v)
878 {
879 	struct carp_softc *sc = v;
880 
881 	CARP_SCLOCK(sc);
882 	carp_send_ad_locked(sc);
883 	CARP_SCUNLOCK(sc);
884 }
885 
886 static void
887 carp_send_ad_locked(struct carp_softc *sc)
888 {
889 	struct carp_header ch;
890 	struct timeval tv;
891 	struct carp_header *ch_ptr;
892 	struct mbuf *m;
893 	int len, advbase, advskew;
894 
895 	CARP_SCLOCK_ASSERT(sc);
896 
897 	/* bow out if we've lost our UPness or RUNNINGuiness */
898 	if (!((SC2IFP(sc)->if_flags & IFF_UP) &&
899 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
900 		advbase = 255;
901 		advskew = 255;
902 	} else {
903 		advbase = sc->sc_advbase;
904 		if (!carp_suppress_preempt || sc->sc_advskew > 240)
905 			advskew = sc->sc_advskew;
906 		else
907 			advskew = 240;
908 		tv.tv_sec = advbase;
909 		tv.tv_usec = advskew * 1000000 / 256;
910 	}
911 
912 	ch.carp_version = CARP_VERSION;
913 	ch.carp_type = CARP_ADVERTISEMENT;
914 	ch.carp_vhid = sc->sc_vhid;
915 	ch.carp_advbase = advbase;
916 	ch.carp_advskew = advskew;
917 	ch.carp_authlen = 7;	/* XXX DEFINE */
918 	ch.carp_pad1 = 0;	/* must be zero */
919 	ch.carp_cksum = 0;
920 
921 #ifdef INET
922 	if (sc->sc_ia) {
923 		struct ip *ip;
924 
925 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
926 		if (m == NULL) {
927 			SC2IFP(sc)->if_oerrors++;
928 			CARPSTATS_INC(carps_onomem);
929 			/* XXX maybe less ? */
930 			if (advbase != 255 || advskew != 255)
931 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
932 				    carp_send_ad, sc);
933 			return;
934 		}
935 		len = sizeof(*ip) + sizeof(ch);
936 		m->m_pkthdr.len = len;
937 		m->m_pkthdr.rcvif = NULL;
938 		m->m_len = len;
939 		MH_ALIGN(m, m->m_len);
940 		m->m_flags |= M_MCAST;
941 		ip = mtod(m, struct ip *);
942 		ip->ip_v = IPVERSION;
943 		ip->ip_hl = sizeof(*ip) >> 2;
944 		ip->ip_tos = IPTOS_LOWDELAY;
945 		ip->ip_len = len;
946 		ip->ip_id = ip_newid();
947 		ip->ip_off = IP_DF;
948 		ip->ip_ttl = CARP_DFLTTL;
949 		ip->ip_p = IPPROTO_CARP;
950 		ip->ip_sum = 0;
951 		ip->ip_src.s_addr = sc->sc_ia->ia_addr.sin_addr.s_addr;
952 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
953 
954 		ch_ptr = (struct carp_header *)(&ip[1]);
955 		bcopy(&ch, ch_ptr, sizeof(ch));
956 		if (carp_prepare_ad(m, sc, ch_ptr))
957 			return;
958 
959 		m->m_data += sizeof(*ip);
960 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip));
961 		m->m_data -= sizeof(*ip);
962 
963 		getmicrotime(&SC2IFP(sc)->if_lastchange);
964 		SC2IFP(sc)->if_opackets++;
965 		SC2IFP(sc)->if_obytes += len;
966 		CARPSTATS_INC(carps_opackets);
967 
968 		if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)) {
969 			SC2IFP(sc)->if_oerrors++;
970 			if (sc->sc_sendad_errors < INT_MAX)
971 				sc->sc_sendad_errors++;
972 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
973 				carp_suppress_preempt++;
974 				if (carp_suppress_preempt == 1) {
975 					CARP_SCUNLOCK(sc);
976 					carp_send_ad_all();
977 					CARP_SCLOCK(sc);
978 				}
979 			}
980 			sc->sc_sendad_success = 0;
981 		} else {
982 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
983 				if (++sc->sc_sendad_success >=
984 				    CARP_SENDAD_MIN_SUCCESS) {
985 					carp_suppress_preempt--;
986 					sc->sc_sendad_errors = 0;
987 				}
988 			} else
989 				sc->sc_sendad_errors = 0;
990 		}
991 	}
992 #endif /* INET */
993 #ifdef INET6
994 	if (sc->sc_ia6) {
995 		struct ip6_hdr *ip6;
996 
997 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
998 		if (m == NULL) {
999 			SC2IFP(sc)->if_oerrors++;
1000 			CARPSTATS_INC(carps_onomem);
1001 			/* XXX maybe less ? */
1002 			if (advbase != 255 || advskew != 255)
1003 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1004 				    carp_send_ad, sc);
1005 			return;
1006 		}
1007 		len = sizeof(*ip6) + sizeof(ch);
1008 		m->m_pkthdr.len = len;
1009 		m->m_pkthdr.rcvif = NULL;
1010 		m->m_len = len;
1011 		MH_ALIGN(m, m->m_len);
1012 		m->m_flags |= M_MCAST;
1013 		ip6 = mtod(m, struct ip6_hdr *);
1014 		bzero(ip6, sizeof(*ip6));
1015 		ip6->ip6_vfc |= IPV6_VERSION;
1016 		ip6->ip6_hlim = CARP_DFLTTL;
1017 		ip6->ip6_nxt = IPPROTO_CARP;
1018 		bcopy(&sc->sc_ia6->ia_addr.sin6_addr, &ip6->ip6_src,
1019 		    sizeof(struct in6_addr));
1020 		/* set the multicast destination */
1021 
1022 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1023 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1024 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1025 			SC2IFP(sc)->if_oerrors++;
1026 			m_freem(m);
1027 			CARP_LOG("%s: in6_setscope failed\n", __func__);
1028 			return;
1029 		}
1030 
1031 		ch_ptr = (struct carp_header *)(&ip6[1]);
1032 		bcopy(&ch, ch_ptr, sizeof(ch));
1033 		if (carp_prepare_ad(m, sc, ch_ptr))
1034 			return;
1035 
1036 		m->m_data += sizeof(*ip6);
1037 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip6));
1038 		m->m_data -= sizeof(*ip6);
1039 
1040 		getmicrotime(&SC2IFP(sc)->if_lastchange);
1041 		SC2IFP(sc)->if_opackets++;
1042 		SC2IFP(sc)->if_obytes += len;
1043 		CARPSTATS_INC(carps_opackets6);
1044 
1045 		if (ip6_output(m, NULL, NULL, 0, &sc->sc_im6o, NULL, NULL)) {
1046 			SC2IFP(sc)->if_oerrors++;
1047 			if (sc->sc_sendad_errors < INT_MAX)
1048 				sc->sc_sendad_errors++;
1049 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
1050 				carp_suppress_preempt++;
1051 				if (carp_suppress_preempt == 1) {
1052 					CARP_SCUNLOCK(sc);
1053 					carp_send_ad_all();
1054 					CARP_SCLOCK(sc);
1055 				}
1056 			}
1057 			sc->sc_sendad_success = 0;
1058 		} else {
1059 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1060 				if (++sc->sc_sendad_success >=
1061 				    CARP_SENDAD_MIN_SUCCESS) {
1062 					carp_suppress_preempt--;
1063 					sc->sc_sendad_errors = 0;
1064 				}
1065 			} else
1066 				sc->sc_sendad_errors = 0;
1067 		}
1068 	}
1069 #endif /* INET6 */
1070 
1071 	if (advbase != 255 || advskew != 255)
1072 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1073 		    carp_send_ad, sc);
1074 
1075 }
1076 
1077 /*
1078  * Broadcast a gratuitous ARP request containing
1079  * the virtual router MAC address for each IP address
1080  * associated with the virtual router.
1081  */
1082 static void
1083 carp_send_arp(struct carp_softc *sc)
1084 {
1085 	struct ifaddr *ifa;
1086 
1087 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1088 
1089 		if (ifa->ifa_addr->sa_family != AF_INET)
1090 			continue;
1091 
1092 /*		arprequest(sc->sc_carpdev, &in, &in, IF_LLADDR(sc->sc_ifp)); */
1093 		arp_ifinit2(sc->sc_carpdev, ifa, IF_LLADDR(sc->sc_ifp));
1094 
1095 		DELAY(1000);	/* XXX */
1096 	}
1097 }
1098 
1099 #ifdef INET6
1100 static void
1101 carp_send_na(struct carp_softc *sc)
1102 {
1103 	struct ifaddr *ifa;
1104 	struct in6_addr *in6;
1105 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1106 
1107 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1108 
1109 		if (ifa->ifa_addr->sa_family != AF_INET6)
1110 			continue;
1111 
1112 		in6 = &ifatoia6(ifa)->ia_addr.sin6_addr;
1113 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1114 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1115 		DELAY(1000);	/* XXX */
1116 	}
1117 }
1118 #endif /* INET6 */
1119 
1120 static int
1121 carp_addrcount(struct carp_if *cif, struct in_ifaddr *ia, int type)
1122 {
1123 	struct carp_softc *vh;
1124 	struct ifaddr *ifa;
1125 	int count = 0;
1126 
1127 	CARP_LOCK_ASSERT(cif);
1128 
1129 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1130 		if ((type == CARP_COUNT_RUNNING &&
1131 		    (SC2IFP(vh)->if_flags & IFF_UP) &&
1132 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) ||
1133 		    (type == CARP_COUNT_MASTER && vh->sc_state == MASTER)) {
1134 			IF_ADDR_LOCK(SC2IFP(vh));
1135 			TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1136 			    ifa_list) {
1137 				if (ifa->ifa_addr->sa_family == AF_INET &&
1138 				    ia->ia_addr.sin_addr.s_addr ==
1139 				    ifatoia(ifa)->ia_addr.sin_addr.s_addr)
1140 					count++;
1141 			}
1142 			IF_ADDR_UNLOCK(SC2IFP(vh));
1143 		}
1144 	}
1145 	return (count);
1146 }
1147 
1148 int
1149 carp_iamatch(void *v, struct in_ifaddr *ia,
1150     struct in_addr *isaddr, u_int8_t **enaddr)
1151 {
1152 	struct carp_if *cif = v;
1153 	struct carp_softc *vh;
1154 	int index, count = 0;
1155 	struct ifaddr *ifa;
1156 
1157 	CARP_LOCK(cif);
1158 
1159 	if (carp_opts[CARPCTL_ARPBALANCE]) {
1160 		/*
1161 		 * XXX proof of concept implementation.
1162 		 * We use the source ip to decide which virtual host should
1163 		 * handle the request. If we're master of that virtual host,
1164 		 * then we respond, otherwise, just drop the arp packet on
1165 		 * the floor.
1166 		 */
1167 		count = carp_addrcount(cif, ia, CARP_COUNT_RUNNING);
1168 		if (count == 0) {
1169 			/* should never reach this */
1170 			CARP_UNLOCK(cif);
1171 			return (0);
1172 		}
1173 
1174 		/* this should be a hash, like pf_hash() */
1175 		index = ntohl(isaddr->s_addr) % count;
1176 		count = 0;
1177 
1178 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1179 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1180 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) {
1181 				IF_ADDR_LOCK(SC2IFP(vh));
1182 				TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1183 				    ifa_list) {
1184 					if (ifa->ifa_addr->sa_family ==
1185 					    AF_INET &&
1186 					    ia->ia_addr.sin_addr.s_addr ==
1187 					    ifatoia(ifa)->ia_addr.sin_addr.s_addr) {
1188 						if (count == index) {
1189 							if (vh->sc_state ==
1190 							    MASTER) {
1191 								*enaddr = IF_LLADDR(vh->sc_ifp);
1192 								IF_ADDR_UNLOCK(SC2IFP(vh));
1193 								CARP_UNLOCK(cif);
1194 								return (1);
1195 							} else {
1196 								IF_ADDR_UNLOCK(SC2IFP(vh));
1197 								CARP_UNLOCK(cif);
1198 								return (0);
1199 							}
1200 						}
1201 						count++;
1202 					}
1203 				}
1204 				IF_ADDR_UNLOCK(SC2IFP(vh));
1205 			}
1206 		}
1207 	} else {
1208 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1209 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1210 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1211 			    ia->ia_ifp == SC2IFP(vh) &&
1212 			    vh->sc_state == MASTER) {
1213 				*enaddr = IF_LLADDR(vh->sc_ifp);
1214 				CARP_UNLOCK(cif);
1215 				return (1);
1216 			}
1217 		}
1218 	}
1219 	CARP_UNLOCK(cif);
1220 	return (0);
1221 }
1222 
1223 #ifdef INET6
1224 struct ifaddr *
1225 carp_iamatch6(void *v, struct in6_addr *taddr)
1226 {
1227 	struct carp_if *cif = v;
1228 	struct carp_softc *vh;
1229 	struct ifaddr *ifa;
1230 
1231 	CARP_LOCK(cif);
1232 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1233 		IF_ADDR_LOCK(SC2IFP(vh));
1234 		TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist, ifa_list) {
1235 			if (IN6_ARE_ADDR_EQUAL(taddr,
1236 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1237  			    (SC2IFP(vh)->if_flags & IFF_UP) &&
1238 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1239 			    vh->sc_state == MASTER) {
1240 				ifa_ref(ifa);
1241 				IF_ADDR_UNLOCK(SC2IFP(vh));
1242 			    	CARP_UNLOCK(cif);
1243 				return (ifa);
1244 			}
1245 		}
1246 		IF_ADDR_UNLOCK(SC2IFP(vh));
1247 	}
1248 	CARP_UNLOCK(cif);
1249 
1250 	return (NULL);
1251 }
1252 
1253 void *
1254 carp_macmatch6(void *v, struct mbuf *m, const struct in6_addr *taddr)
1255 {
1256 	struct m_tag *mtag;
1257 	struct carp_if *cif = v;
1258 	struct carp_softc *sc;
1259 	struct ifaddr *ifa;
1260 
1261 	CARP_LOCK(cif);
1262 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
1263 		IF_ADDR_LOCK(SC2IFP(sc));
1264 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1265 			if (IN6_ARE_ADDR_EQUAL(taddr,
1266 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1267  			    (SC2IFP(sc)->if_flags & IFF_UP) &&
1268 			    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING)) {
1269 				struct ifnet *ifp = SC2IFP(sc);
1270 				mtag = m_tag_get(PACKET_TAG_CARP,
1271 				    sizeof(struct ifnet *), M_NOWAIT);
1272 				if (mtag == NULL) {
1273 					/* better a bit than nothing */
1274 					IF_ADDR_UNLOCK(SC2IFP(sc));
1275 					CARP_UNLOCK(cif);
1276 					return (IF_LLADDR(sc->sc_ifp));
1277 				}
1278 				bcopy(&ifp, (caddr_t)(mtag + 1),
1279 				    sizeof(struct ifnet *));
1280 				m_tag_prepend(m, mtag);
1281 
1282 				IF_ADDR_UNLOCK(SC2IFP(sc));
1283 				CARP_UNLOCK(cif);
1284 				return (IF_LLADDR(sc->sc_ifp));
1285 			}
1286 		}
1287 		IF_ADDR_UNLOCK(SC2IFP(sc));
1288 	}
1289 	CARP_UNLOCK(cif);
1290 
1291 	return (NULL);
1292 }
1293 #endif
1294 
1295 struct ifnet *
1296 carp_forus(void *v, void *dhost)
1297 {
1298 	struct carp_if *cif = v;
1299 	struct carp_softc *vh;
1300 	u_int8_t *ena = dhost;
1301 
1302 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1303 		return (NULL);
1304 
1305 	CARP_LOCK(cif);
1306 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list)
1307 		if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1308 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1309 		    vh->sc_state == MASTER &&
1310 		    !bcmp(dhost, IF_LLADDR(vh->sc_ifp), ETHER_ADDR_LEN)) {
1311 		    	CARP_UNLOCK(cif);
1312 			return (SC2IFP(vh));
1313 		}
1314 
1315     	CARP_UNLOCK(cif);
1316 	return (NULL);
1317 }
1318 
1319 static void
1320 carp_master_down(void *v)
1321 {
1322 	struct carp_softc *sc = v;
1323 
1324 	CARP_SCLOCK(sc);
1325 	carp_master_down_locked(sc);
1326 	CARP_SCUNLOCK(sc);
1327 }
1328 
1329 static void
1330 carp_master_down_locked(struct carp_softc *sc)
1331 {
1332 	if (sc->sc_carpdev)
1333 		CARP_SCLOCK_ASSERT(sc);
1334 
1335 	switch (sc->sc_state) {
1336 	case INIT:
1337 		printf("%s: master_down event in INIT state\n",
1338 		    SC2IFP(sc)->if_xname);
1339 		break;
1340 	case MASTER:
1341 		break;
1342 	case BACKUP:
1343 		carp_set_state(sc, MASTER);
1344 		carp_send_ad_locked(sc);
1345 		carp_send_arp(sc);
1346 #ifdef INET6
1347 		carp_send_na(sc);
1348 #endif /* INET6 */
1349 		carp_setrun(sc, 0);
1350 		carp_setroute(sc, RTM_ADD);
1351 		break;
1352 	}
1353 }
1354 
1355 /*
1356  * When in backup state, af indicates whether to reset the master down timer
1357  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1358  */
1359 static void
1360 carp_setrun(struct carp_softc *sc, sa_family_t af)
1361 {
1362 	struct timeval tv;
1363 
1364 	if (sc->sc_carpdev == NULL) {
1365 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1366 		carp_set_state(sc, INIT);
1367 		return;
1368 	} else
1369 		CARP_SCLOCK_ASSERT(sc);
1370 
1371 	if (SC2IFP(sc)->if_flags & IFF_UP &&
1372 	    sc->sc_vhid > 0 && (sc->sc_naddrs || sc->sc_naddrs6))
1373 		SC2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
1374 	else {
1375 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1376 		carp_setroute(sc, RTM_DELETE);
1377 		return;
1378 	}
1379 
1380 	switch (sc->sc_state) {
1381 	case INIT:
1382 		if (carp_opts[CARPCTL_PREEMPT] && !carp_suppress_preempt) {
1383 			carp_send_ad_locked(sc);
1384 			carp_send_arp(sc);
1385 #ifdef INET6
1386 			carp_send_na(sc);
1387 #endif /* INET6 */
1388 			CARP_DEBUG("%s: INIT -> MASTER (preempting)\n",
1389 			    SC2IFP(sc)->if_xname);
1390 			carp_set_state(sc, MASTER);
1391 			carp_setroute(sc, RTM_ADD);
1392 		} else {
1393 			CARP_DEBUG("%s: INIT -> BACKUP\n", SC2IFP(sc)->if_xname);
1394 			carp_set_state(sc, BACKUP);
1395 			carp_setroute(sc, RTM_DELETE);
1396 			carp_setrun(sc, 0);
1397 		}
1398 		break;
1399 	case BACKUP:
1400 		callout_stop(&sc->sc_ad_tmo);
1401 		tv.tv_sec = 3 * sc->sc_advbase;
1402 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1403 		switch (af) {
1404 #ifdef INET
1405 		case AF_INET:
1406 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1407 			    carp_master_down, sc);
1408 			break;
1409 #endif /* INET */
1410 #ifdef INET6
1411 		case AF_INET6:
1412 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1413 			    carp_master_down, sc);
1414 			break;
1415 #endif /* INET6 */
1416 		default:
1417 			if (sc->sc_naddrs)
1418 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1419 				    carp_master_down, sc);
1420 			if (sc->sc_naddrs6)
1421 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1422 				    carp_master_down, sc);
1423 			break;
1424 		}
1425 		break;
1426 	case MASTER:
1427 		tv.tv_sec = sc->sc_advbase;
1428 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1429 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1430 		    carp_send_ad, sc);
1431 		break;
1432 	}
1433 }
1434 
1435 static void
1436 carp_multicast_cleanup(struct carp_softc *sc)
1437 {
1438 	struct ip_moptions *imo = &sc->sc_imo;
1439 	u_int16_t n = imo->imo_num_memberships;
1440 
1441 	/* Clean up our own multicast memberships */
1442 	while (n-- > 0) {
1443 		if (imo->imo_membership[n] != NULL) {
1444 			in_delmulti(imo->imo_membership[n]);
1445 			imo->imo_membership[n] = NULL;
1446 		}
1447 	}
1448 	KASSERT(imo->imo_mfilters == NULL,
1449 	   ("%s: imo_mfilters != NULL", __func__));
1450 	imo->imo_num_memberships = 0;
1451 	imo->imo_multicast_ifp = NULL;
1452 }
1453 
1454 #ifdef INET6
1455 static void
1456 carp_multicast6_cleanup(struct carp_softc *sc)
1457 {
1458 	struct ip6_moptions *im6o = &sc->sc_im6o;
1459 	u_int16_t n = im6o->im6o_num_memberships;
1460 
1461 	while (n-- > 0) {
1462 		if (im6o->im6o_membership[n] != NULL) {
1463 			in6_mc_leave(im6o->im6o_membership[n], NULL);
1464 			im6o->im6o_membership[n] = NULL;
1465 		}
1466 	}
1467 	KASSERT(im6o->im6o_mfilters == NULL,
1468 	   ("%s: im6o_mfilters != NULL", __func__));
1469 	im6o->im6o_num_memberships = 0;
1470 	im6o->im6o_multicast_ifp = NULL;
1471 }
1472 #endif
1473 
1474 static int
1475 carp_set_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1476 {
1477 	struct ifnet *ifp;
1478 	struct carp_if *cif;
1479 	struct in_ifaddr *ia, *ia_if;
1480 	struct ip_moptions *imo = &sc->sc_imo;
1481 	struct in_addr addr;
1482 	u_long iaddr = htonl(sin->sin_addr.s_addr);
1483 	int own, error;
1484 
1485 	if (sin->sin_addr.s_addr == 0) {
1486 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1487 			carp_set_state(sc, INIT);
1488 		if (sc->sc_naddrs)
1489 			SC2IFP(sc)->if_flags |= IFF_UP;
1490 		if (sc->sc_carpdev)
1491 			CARP_SCLOCK(sc);
1492 		carp_setrun(sc, 0);
1493 		if (sc->sc_carpdev)
1494 			CARP_SCUNLOCK(sc);
1495 		return (0);
1496 	}
1497 
1498 	/* we have to do it by hands to check we won't match on us */
1499 	ia_if = NULL; own = 0;
1500 	IN_IFADDR_RLOCK();
1501 	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
1502 		/* and, yeah, we need a multicast-capable iface too */
1503 		if (ia->ia_ifp != SC2IFP(sc) &&
1504 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1505 		    (iaddr & ia->ia_subnetmask) == ia->ia_subnet) {
1506 			if (!ia_if)
1507 				ia_if = ia;
1508 			if (sin->sin_addr.s_addr ==
1509 			    ia->ia_addr.sin_addr.s_addr)
1510 				own++;
1511 		}
1512 	}
1513 
1514 	if (!ia_if) {
1515 		IN_IFADDR_RUNLOCK();
1516 		return (EADDRNOTAVAIL);
1517 	}
1518 
1519 	ia = ia_if;
1520 	ifa_ref(&ia->ia_ifa);
1521 	IN_IFADDR_RUNLOCK();
1522 
1523 	ifp = ia->ia_ifp;
1524 
1525 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1526 	    (imo->imo_multicast_ifp && imo->imo_multicast_ifp != ifp)) {
1527 		ifa_free(&ia->ia_ifa);
1528 		return (EADDRNOTAVAIL);
1529 	}
1530 
1531 	if (imo->imo_num_memberships == 0) {
1532 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1533 		if ((imo->imo_membership[0] = in_addmulti(&addr, ifp)) ==
1534 		    NULL) {
1535 			ifa_free(&ia->ia_ifa);
1536 			return (ENOBUFS);
1537 		}
1538 		imo->imo_num_memberships++;
1539 		imo->imo_multicast_ifp = ifp;
1540 		imo->imo_multicast_ttl = CARP_DFLTTL;
1541 		imo->imo_multicast_loop = 0;
1542 	}
1543 
1544 	if (!ifp->if_carp) {
1545 
1546 		cif = malloc(sizeof(*cif), M_CARP,
1547 		    M_WAITOK|M_ZERO);
1548 		if (!cif) {
1549 			error = ENOBUFS;
1550 			goto cleanup;
1551 		}
1552 		if ((error = ifpromisc(ifp, 1))) {
1553 			free(cif, M_CARP);
1554 			goto cleanup;
1555 		}
1556 
1557 		CARP_LOCK_INIT(cif);
1558 		CARP_LOCK(cif);
1559 		cif->vhif_ifp = ifp;
1560 		TAILQ_INIT(&cif->vhif_vrs);
1561 		ifp->if_carp = cif;
1562 
1563 	} else {
1564 		struct carp_softc *vr;
1565 
1566 		cif = (struct carp_if *)ifp->if_carp;
1567 		CARP_LOCK(cif);
1568 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1569 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1570 				CARP_UNLOCK(cif);
1571 				error = EEXIST;
1572 				goto cleanup;
1573 			}
1574 	}
1575 	sc->sc_ia = ia;
1576 	sc->sc_carpdev = ifp;
1577 
1578 	{ /* XXX prevent endless loop if already in queue */
1579 	struct carp_softc *vr, *after = NULL;
1580 	int myself = 0;
1581 	cif = (struct carp_if *)ifp->if_carp;
1582 
1583 	/* XXX: cif should not change, right? So we still hold the lock */
1584 	CARP_LOCK_ASSERT(cif);
1585 
1586 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1587 		if (vr == sc)
1588 			myself = 1;
1589 		if (vr->sc_vhid < sc->sc_vhid)
1590 			after = vr;
1591 	}
1592 
1593 	if (!myself) {
1594 		/* We're trying to keep things in order */
1595 		if (after == NULL) {
1596 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1597 		} else {
1598 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1599 		}
1600 		cif->vhif_nvrs++;
1601 	}
1602 	}
1603 
1604 	sc->sc_naddrs++;
1605 	SC2IFP(sc)->if_flags |= IFF_UP;
1606 	if (own)
1607 		sc->sc_advskew = 0;
1608 	carp_sc_state_locked(sc);
1609 	carp_setrun(sc, 0);
1610 
1611 	CARP_UNLOCK(cif);
1612 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1613 
1614 	return (0);
1615 
1616 cleanup:
1617 	in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1618 	ifa_free(&ia->ia_ifa);
1619 	return (error);
1620 }
1621 
1622 static int
1623 carp_del_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1624 {
1625 	int error = 0;
1626 
1627 	if (!--sc->sc_naddrs) {
1628 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1629 		struct ip_moptions *imo = &sc->sc_imo;
1630 
1631 		CARP_LOCK(cif);
1632 		callout_stop(&sc->sc_ad_tmo);
1633 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1634 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1635 		sc->sc_vhid = -1;
1636 		in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1637 		imo->imo_multicast_ifp = NULL;
1638 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1639 		if (!--cif->vhif_nvrs) {
1640 			sc->sc_carpdev->if_carp = NULL;
1641 			CARP_LOCK_DESTROY(cif);
1642 			free(cif, M_IFADDR);
1643 		} else {
1644 			CARP_UNLOCK(cif);
1645 		}
1646 	}
1647 
1648 	return (error);
1649 }
1650 
1651 #ifdef INET6
1652 static int
1653 carp_set_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1654 {
1655 	struct ifnet *ifp;
1656 	struct carp_if *cif;
1657 	struct in6_ifaddr *ia, *ia_if;
1658 	struct ip6_moptions *im6o = &sc->sc_im6o;
1659 	struct in6_addr in6;
1660 	int own, error;
1661 
1662 	error = 0;
1663 
1664 	if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
1665 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1666 			carp_set_state(sc, INIT);
1667 		if (sc->sc_naddrs6)
1668 			SC2IFP(sc)->if_flags |= IFF_UP;
1669 		if (sc->sc_carpdev)
1670 			CARP_SCLOCK(sc);
1671 		carp_setrun(sc, 0);
1672 		if (sc->sc_carpdev)
1673 			CARP_SCUNLOCK(sc);
1674 		return (0);
1675 	}
1676 
1677 	/* we have to do it by hands to check we won't match on us */
1678 	ia_if = NULL; own = 0;
1679 	IN6_IFADDR_RLOCK();
1680 	TAILQ_FOREACH(ia, &V_in6_ifaddrhead, ia_link) {
1681 		int i;
1682 
1683 		for (i = 0; i < 4; i++) {
1684 			if ((sin6->sin6_addr.s6_addr32[i] &
1685 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]) !=
1686 			    (ia->ia_addr.sin6_addr.s6_addr32[i] &
1687 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]))
1688 				break;
1689 		}
1690 		/* and, yeah, we need a multicast-capable iface too */
1691 		if (ia->ia_ifp != SC2IFP(sc) &&
1692 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1693 		    (i == 4)) {
1694 			if (!ia_if)
1695 				ia_if = ia;
1696 			if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr,
1697 			    &ia->ia_addr.sin6_addr))
1698 				own++;
1699 		}
1700 	}
1701 
1702 	if (!ia_if) {
1703 		IN6_IFADDR_RUNLOCK();
1704 		return (EADDRNOTAVAIL);
1705 	}
1706 	ia = ia_if;
1707 	ifa_ref(&ia->ia_ifa);
1708 	IN6_IFADDR_RUNLOCK();
1709 	ifp = ia->ia_ifp;
1710 
1711 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1712 	    (im6o->im6o_multicast_ifp && im6o->im6o_multicast_ifp != ifp)) {
1713 		ifa_free(&ia->ia_ifa);
1714 		return (EADDRNOTAVAIL);
1715 	}
1716 
1717 	if (!sc->sc_naddrs6) {
1718 		struct in6_multi *in6m;
1719 
1720 		im6o->im6o_multicast_ifp = ifp;
1721 
1722 		/* join CARP multicast address */
1723 		bzero(&in6, sizeof(in6));
1724 		in6.s6_addr16[0] = htons(0xff02);
1725 		in6.s6_addr8[15] = 0x12;
1726 		if (in6_setscope(&in6, ifp, NULL) != 0)
1727 			goto cleanup;
1728 		in6m = NULL;
1729 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1730 		if (error)
1731 			goto cleanup;
1732 		im6o->im6o_membership[0] = in6m;
1733 		im6o->im6o_num_memberships++;
1734 
1735 		/* join solicited multicast address */
1736 		bzero(&in6, sizeof(in6));
1737 		in6.s6_addr16[0] = htons(0xff02);
1738 		in6.s6_addr32[1] = 0;
1739 		in6.s6_addr32[2] = htonl(1);
1740 		in6.s6_addr32[3] = sin6->sin6_addr.s6_addr32[3];
1741 		in6.s6_addr8[12] = 0xff;
1742 		if (in6_setscope(&in6, ifp, NULL) != 0)
1743 			goto cleanup;
1744 		in6m = NULL;
1745 		error = in6_mc_join(ifp, &in6, NULL, &in6m, 0);
1746 		if (error)
1747 			goto cleanup;
1748 		im6o->im6o_membership[1] = in6m;
1749 		im6o->im6o_num_memberships++;
1750 	}
1751 
1752 	if (!ifp->if_carp) {
1753 		cif = malloc(sizeof(*cif), M_CARP,
1754 		    M_WAITOK|M_ZERO);
1755 		if (!cif) {
1756 			error = ENOBUFS;
1757 			goto cleanup;
1758 		}
1759 		if ((error = ifpromisc(ifp, 1))) {
1760 			free(cif, M_CARP);
1761 			goto cleanup;
1762 		}
1763 
1764 		CARP_LOCK_INIT(cif);
1765 		CARP_LOCK(cif);
1766 		cif->vhif_ifp = ifp;
1767 		TAILQ_INIT(&cif->vhif_vrs);
1768 		ifp->if_carp = cif;
1769 
1770 	} else {
1771 		struct carp_softc *vr;
1772 
1773 		cif = (struct carp_if *)ifp->if_carp;
1774 		CARP_LOCK(cif);
1775 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1776 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1777 				CARP_UNLOCK(cif);
1778 				error = EINVAL;
1779 				goto cleanup;
1780 			}
1781 	}
1782 	sc->sc_ia6 = ia;
1783 	sc->sc_carpdev = ifp;
1784 
1785 	{ /* XXX prevent endless loop if already in queue */
1786 	struct carp_softc *vr, *after = NULL;
1787 	int myself = 0;
1788 	cif = (struct carp_if *)ifp->if_carp;
1789 	CARP_LOCK_ASSERT(cif);
1790 
1791 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1792 		if (vr == sc)
1793 			myself = 1;
1794 		if (vr->sc_vhid < sc->sc_vhid)
1795 			after = vr;
1796 	}
1797 
1798 	if (!myself) {
1799 		/* We're trying to keep things in order */
1800 		if (after == NULL) {
1801 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1802 		} else {
1803 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1804 		}
1805 		cif->vhif_nvrs++;
1806 	}
1807 	}
1808 
1809 	sc->sc_naddrs6++;
1810 	SC2IFP(sc)->if_flags |= IFF_UP;
1811 	if (own)
1812 		sc->sc_advskew = 0;
1813 	carp_sc_state_locked(sc);
1814 	carp_setrun(sc, 0);
1815 
1816 	CARP_UNLOCK(cif);
1817 	ifa_free(&ia->ia_ifa);	/* XXXRW: should hold reference for softc. */
1818 
1819 	return (0);
1820 
1821 cleanup:
1822 	if (!sc->sc_naddrs6)
1823 		carp_multicast6_cleanup(sc);
1824 	ifa_free(&ia->ia_ifa);
1825 	return (error);
1826 }
1827 
1828 static int
1829 carp_del_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1830 {
1831 	int error = 0;
1832 
1833 	if (!--sc->sc_naddrs6) {
1834 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1835 
1836 		CARP_LOCK(cif);
1837 		callout_stop(&sc->sc_ad_tmo);
1838 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1839 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1840 		sc->sc_vhid = -1;
1841 		carp_multicast6_cleanup(sc);
1842 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1843 		if (!--cif->vhif_nvrs) {
1844 			CARP_LOCK_DESTROY(cif);
1845 			sc->sc_carpdev->if_carp = NULL;
1846 			free(cif, M_IFADDR);
1847 		} else
1848 			CARP_UNLOCK(cif);
1849 	}
1850 
1851 	return (error);
1852 }
1853 #endif /* INET6 */
1854 
1855 static int
1856 carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
1857 {
1858 	struct carp_softc *sc = ifp->if_softc, *vr;
1859 	struct carpreq carpr;
1860 	struct ifaddr *ifa;
1861 	struct ifreq *ifr;
1862 	struct ifaliasreq *ifra;
1863 	int locked = 0, error = 0;
1864 
1865 	ifa = (struct ifaddr *)addr;
1866 	ifra = (struct ifaliasreq *)addr;
1867 	ifr = (struct ifreq *)addr;
1868 
1869 	switch (cmd) {
1870 	case SIOCSIFADDR:
1871 		switch (ifa->ifa_addr->sa_family) {
1872 #ifdef INET
1873 		case AF_INET:
1874 			SC2IFP(sc)->if_flags |= IFF_UP;
1875 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1876 			    sizeof(struct sockaddr));
1877 			error = carp_set_addr(sc, satosin(ifa->ifa_addr));
1878 			break;
1879 #endif /* INET */
1880 #ifdef INET6
1881 		case AF_INET6:
1882 			SC2IFP(sc)->if_flags |= IFF_UP;
1883 			error = carp_set_addr6(sc, satosin6(ifa->ifa_addr));
1884 			break;
1885 #endif /* INET6 */
1886 		default:
1887 			error = EAFNOSUPPORT;
1888 			break;
1889 		}
1890 		break;
1891 
1892 	case SIOCAIFADDR:
1893 		switch (ifa->ifa_addr->sa_family) {
1894 #ifdef INET
1895 		case AF_INET:
1896 			SC2IFP(sc)->if_flags |= IFF_UP;
1897 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1898 			    sizeof(struct sockaddr));
1899 			error = carp_set_addr(sc, satosin(&ifra->ifra_addr));
1900 			break;
1901 #endif /* INET */
1902 #ifdef INET6
1903 		case AF_INET6:
1904 			SC2IFP(sc)->if_flags |= IFF_UP;
1905 			error = carp_set_addr6(sc, satosin6(&ifra->ifra_addr));
1906 			break;
1907 #endif /* INET6 */
1908 		default:
1909 			error = EAFNOSUPPORT;
1910 			break;
1911 		}
1912 		break;
1913 
1914 	case SIOCDIFADDR:
1915 		switch (ifa->ifa_addr->sa_family) {
1916 #ifdef INET
1917 		case AF_INET:
1918 			error = carp_del_addr(sc, satosin(&ifra->ifra_addr));
1919 			break;
1920 #endif /* INET */
1921 #ifdef INET6
1922 		case AF_INET6:
1923 			error = carp_del_addr6(sc, satosin6(&ifra->ifra_addr));
1924 			break;
1925 #endif /* INET6 */
1926 		default:
1927 			error = EAFNOSUPPORT;
1928 			break;
1929 		}
1930 		break;
1931 
1932 	case SIOCSIFFLAGS:
1933 		if (sc->sc_carpdev) {
1934 			locked = 1;
1935 			CARP_SCLOCK(sc);
1936 		}
1937 		if (sc->sc_state != INIT && !(ifr->ifr_flags & IFF_UP)) {
1938  			callout_stop(&sc->sc_ad_tmo);
1939  			callout_stop(&sc->sc_md_tmo);
1940  			callout_stop(&sc->sc_md6_tmo);
1941 			if (sc->sc_state == MASTER)
1942 				carp_send_ad_locked(sc);
1943 			carp_set_state(sc, INIT);
1944 			carp_setrun(sc, 0);
1945 		} else if (sc->sc_state == INIT && (ifr->ifr_flags & IFF_UP)) {
1946 			SC2IFP(sc)->if_flags |= IFF_UP;
1947 			carp_setrun(sc, 0);
1948 		}
1949 		break;
1950 
1951 	case SIOCSVH:
1952 		error = priv_check(curthread, PRIV_NETINET_CARP);
1953 		if (error)
1954 			break;
1955 		if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1956 			break;
1957 		error = 1;
1958 		if (sc->sc_carpdev) {
1959 			locked = 1;
1960 			CARP_SCLOCK(sc);
1961 		}
1962 		if (sc->sc_state != INIT && carpr.carpr_state != sc->sc_state) {
1963 			switch (carpr.carpr_state) {
1964 			case BACKUP:
1965 				callout_stop(&sc->sc_ad_tmo);
1966 				carp_set_state(sc, BACKUP);
1967 				carp_setrun(sc, 0);
1968 				carp_setroute(sc, RTM_DELETE);
1969 				break;
1970 			case MASTER:
1971 				carp_master_down_locked(sc);
1972 				break;
1973 			default:
1974 				break;
1975 			}
1976 		}
1977 		if (carpr.carpr_vhid > 0) {
1978 			if (carpr.carpr_vhid > 255) {
1979 				error = EINVAL;
1980 				break;
1981 			}
1982 			if (sc->sc_carpdev) {
1983 				struct carp_if *cif;
1984 				cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1985 				TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1986 					if (vr != sc &&
1987 					    vr->sc_vhid == carpr.carpr_vhid) {
1988 						error = EEXIST;
1989 						break;
1990 					}
1991 				if (error == EEXIST)
1992 					break;
1993 			}
1994 			sc->sc_vhid = carpr.carpr_vhid;
1995 			IF_LLADDR(sc->sc_ifp)[0] = 0;
1996 			IF_LLADDR(sc->sc_ifp)[1] = 0;
1997 			IF_LLADDR(sc->sc_ifp)[2] = 0x5e;
1998 			IF_LLADDR(sc->sc_ifp)[3] = 0;
1999 			IF_LLADDR(sc->sc_ifp)[4] = 1;
2000 			IF_LLADDR(sc->sc_ifp)[5] = sc->sc_vhid;
2001 			error--;
2002 		}
2003 		if (carpr.carpr_advbase > 0 || carpr.carpr_advskew > 0) {
2004 			if (carpr.carpr_advskew >= 255) {
2005 				error = EINVAL;
2006 				break;
2007 			}
2008 			if (carpr.carpr_advbase > 255) {
2009 				error = EINVAL;
2010 				break;
2011 			}
2012 			sc->sc_advbase = carpr.carpr_advbase;
2013 			sc->sc_advskew = carpr.carpr_advskew;
2014 			error--;
2015 		}
2016 		bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
2017 		if (error > 0)
2018 			error = EINVAL;
2019 		else {
2020 			error = 0;
2021 			carp_setrun(sc, 0);
2022 		}
2023 		break;
2024 
2025 	case SIOCGVH:
2026 		/* XXX: lockless read */
2027 		bzero(&carpr, sizeof(carpr));
2028 		carpr.carpr_state = sc->sc_state;
2029 		carpr.carpr_vhid = sc->sc_vhid;
2030 		carpr.carpr_advbase = sc->sc_advbase;
2031 		carpr.carpr_advskew = sc->sc_advskew;
2032 		error = priv_check(curthread, PRIV_NETINET_CARP);
2033 		if (error == 0)
2034 			bcopy(sc->sc_key, carpr.carpr_key,
2035 			    sizeof(carpr.carpr_key));
2036 		error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
2037 		break;
2038 
2039 	default:
2040 		error = EINVAL;
2041 	}
2042 
2043 	if (locked)
2044 		CARP_SCUNLOCK(sc);
2045 
2046 	carp_hmac_prepare(sc);
2047 
2048 	return (error);
2049 }
2050 
2051 /*
2052  * XXX: this is looutput. We should eventually use it from there.
2053  */
2054 static int
2055 carp_looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
2056     struct route *ro)
2057 {
2058 	u_int32_t af;
2059 	struct rtentry *rt = NULL;
2060 
2061 	M_ASSERTPKTHDR(m); /* check if we have the packet header */
2062 
2063 	if (ro != NULL)
2064 		rt = ro->ro_rt;
2065 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
2066 		m_freem(m);
2067 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
2068 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
2069 	}
2070 
2071 	ifp->if_opackets++;
2072 	ifp->if_obytes += m->m_pkthdr.len;
2073 
2074 	/* BPF writes need to be handled specially. */
2075 	if (dst->sa_family == AF_UNSPEC) {
2076 		bcopy(dst->sa_data, &af, sizeof(af));
2077 		dst->sa_family = af;
2078 	}
2079 
2080 #if 1	/* XXX */
2081 	switch (dst->sa_family) {
2082 	case AF_INET:
2083 	case AF_INET6:
2084 	case AF_IPX:
2085 	case AF_APPLETALK:
2086 		break;
2087 	default:
2088 		printf("carp_looutput: af=%d unexpected\n", dst->sa_family);
2089 		m_freem(m);
2090 		return (EAFNOSUPPORT);
2091 	}
2092 #endif
2093 	return(if_simloop(ifp, m, dst->sa_family, 0));
2094 }
2095 
2096 /*
2097  * Start output on carp interface. This function should never be called.
2098  */
2099 static void
2100 carp_start(struct ifnet *ifp)
2101 {
2102 #ifdef DEBUG
2103 	printf("%s: start called\n", ifp->if_xname);
2104 #endif
2105 }
2106 
2107 int
2108 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
2109     struct rtentry *rt)
2110 {
2111 	struct m_tag *mtag;
2112 	struct carp_softc *sc;
2113 	struct ifnet *carp_ifp;
2114 
2115 	if (!sa)
2116 		return (0);
2117 
2118 	switch (sa->sa_family) {
2119 #ifdef INET
2120 	case AF_INET:
2121 		break;
2122 #endif /* INET */
2123 #ifdef INET6
2124 	case AF_INET6:
2125 		break;
2126 #endif /* INET6 */
2127 	default:
2128 		return (0);
2129 	}
2130 
2131 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
2132 	if (mtag == NULL)
2133 		return (0);
2134 
2135 	bcopy(mtag + 1, &carp_ifp, sizeof(struct ifnet *));
2136 	sc = carp_ifp->if_softc;
2137 
2138 	/* Set the source MAC address to Virtual Router MAC Address */
2139 	switch (ifp->if_type) {
2140 	case IFT_ETHER:
2141 	case IFT_L2VLAN: {
2142 			struct ether_header *eh;
2143 
2144 			eh = mtod(m, struct ether_header *);
2145 			eh->ether_shost[0] = 0;
2146 			eh->ether_shost[1] = 0;
2147 			eh->ether_shost[2] = 0x5e;
2148 			eh->ether_shost[3] = 0;
2149 			eh->ether_shost[4] = 1;
2150 			eh->ether_shost[5] = sc->sc_vhid;
2151 		}
2152 		break;
2153 	case IFT_FDDI: {
2154 			struct fddi_header *fh;
2155 
2156 			fh = mtod(m, struct fddi_header *);
2157 			fh->fddi_shost[0] = 0;
2158 			fh->fddi_shost[1] = 0;
2159 			fh->fddi_shost[2] = 0x5e;
2160 			fh->fddi_shost[3] = 0;
2161 			fh->fddi_shost[4] = 1;
2162 			fh->fddi_shost[5] = sc->sc_vhid;
2163 		}
2164 		break;
2165 	case IFT_ISO88025: {
2166  			struct iso88025_header *th;
2167  			th = mtod(m, struct iso88025_header *);
2168 			th->iso88025_shost[0] = 3;
2169 			th->iso88025_shost[1] = 0;
2170 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
2171 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
2172 			th->iso88025_shost[4] = 0;
2173 			th->iso88025_shost[5] = 0;
2174 		}
2175 		break;
2176 	default:
2177 		printf("%s: carp is not supported for this interface type\n",
2178 		    ifp->if_xname);
2179 		return (EOPNOTSUPP);
2180 	}
2181 
2182 	return (0);
2183 }
2184 
2185 static void
2186 carp_set_state(struct carp_softc *sc, int state)
2187 {
2188 	int link_state;
2189 
2190 	if (sc->sc_carpdev)
2191 		CARP_SCLOCK_ASSERT(sc);
2192 
2193 	if (sc->sc_state == state)
2194 		return;
2195 
2196 	sc->sc_state = state;
2197 	switch (state) {
2198 	case BACKUP:
2199 		link_state = LINK_STATE_DOWN;
2200 		break;
2201 	case MASTER:
2202 		link_state = LINK_STATE_UP;
2203 		break;
2204 	default:
2205 		link_state = LINK_STATE_UNKNOWN;
2206 		break;
2207 	}
2208 	if_link_state_change(SC2IFP(sc), link_state);
2209 }
2210 
2211 void
2212 carp_carpdev_state(void *v)
2213 {
2214 	struct carp_if *cif = v;
2215 
2216 	CARP_LOCK(cif);
2217 	carp_carpdev_state_locked(cif);
2218 	CARP_UNLOCK(cif);
2219 }
2220 
2221 static void
2222 carp_carpdev_state_locked(struct carp_if *cif)
2223 {
2224 	struct carp_softc *sc;
2225 
2226 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list)
2227 		carp_sc_state_locked(sc);
2228 }
2229 
2230 static void
2231 carp_sc_state_locked(struct carp_softc *sc)
2232 {
2233 	CARP_SCLOCK_ASSERT(sc);
2234 
2235 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2236 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
2237 		sc->sc_flags_backup = SC2IFP(sc)->if_flags;
2238 		SC2IFP(sc)->if_flags &= ~IFF_UP;
2239 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
2240 		callout_stop(&sc->sc_ad_tmo);
2241 		callout_stop(&sc->sc_md_tmo);
2242 		callout_stop(&sc->sc_md6_tmo);
2243 		carp_set_state(sc, INIT);
2244 		carp_setrun(sc, 0);
2245 		if (!sc->sc_suppress) {
2246 			carp_suppress_preempt++;
2247 			if (carp_suppress_preempt == 1) {
2248 				CARP_SCUNLOCK(sc);
2249 				carp_send_ad_all();
2250 				CARP_SCLOCK(sc);
2251 			}
2252 		}
2253 		sc->sc_suppress = 1;
2254 	} else {
2255 		SC2IFP(sc)->if_flags |= sc->sc_flags_backup;
2256 		carp_set_state(sc, INIT);
2257 		carp_setrun(sc, 0);
2258 		if (sc->sc_suppress)
2259 			carp_suppress_preempt--;
2260 		sc->sc_suppress = 0;
2261 	}
2262 
2263 	return;
2264 }
2265 
2266 static int
2267 carp_modevent(module_t mod, int type, void *data)
2268 {
2269 	switch (type) {
2270 	case MOD_LOAD:
2271 		if_detach_event_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
2272 		    carp_ifdetach, NULL, EVENTHANDLER_PRI_ANY);
2273 		if (if_detach_event_tag == NULL)
2274 			return (ENOMEM);
2275 		mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2276 		LIST_INIT(&carpif_list);
2277 		if_clone_attach(&carp_cloner);
2278 		break;
2279 
2280 	case MOD_UNLOAD:
2281 		EVENTHANDLER_DEREGISTER(ifnet_departure_event, if_detach_event_tag);
2282 		if_clone_detach(&carp_cloner);
2283 		mtx_destroy(&carp_mtx);
2284 		break;
2285 
2286 	default:
2287 		return (EINVAL);
2288 	}
2289 
2290 	return (0);
2291 }
2292 
2293 static moduledata_t carp_mod = {
2294 	"carp",
2295 	carp_modevent,
2296 	0
2297 };
2298 
2299 DECLARE_MODULE(carp, carp_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
2300