xref: /freebsd/sys/netinet/ip_carp.c (revision 271c3a9060f2ee55607ebe146523f888e1db2654)
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 #include <sys/vimage.h>
56 
57 #include <machine/stdarg.h>
58 
59 #include <net/bpf.h>
60 #include <net/ethernet.h>
61 #include <net/fddi.h>
62 #include <net/iso88025.h>
63 #include <net/if.h>
64 #include <net/if_clone.h>
65 #include <net/if_dl.h>
66 #include <net/if_types.h>
67 #include <net/route.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 rtentry *);
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 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
277 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
278 			if (ifa->ifa_addr->sa_family == AF_INET &&
279 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
280 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
281 				cur.s_addr = in.s_addr;
282 				found++;
283 			}
284 		}
285 		if (found)
286 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
287 	} while (found);
288 #endif /* INET */
289 #ifdef INET6
290 	memset(&cur6, 0, sizeof(cur6));
291 	do {
292 		found = 0;
293 		last6 = cur6;
294 		memset(&cur6, 0xff, sizeof(cur6));
295 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
296 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
297 			if (IN6_IS_SCOPE_EMBED(&in6))
298 				in6.s6_addr16[1] = 0;
299 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
300 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
301 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
302 				cur6 = in6;
303 				found++;
304 			}
305 		}
306 		if (found)
307 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
308 	} while (found);
309 #endif /* INET6 */
310 
311 	/* convert ipad to opad */
312 	for (i = 0; i < sizeof(sc->sc_pad); i++)
313 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
314 
315 	if (sc->sc_carpdev)
316 		CARP_SCUNLOCK(sc);
317 }
318 
319 static void
320 carp_hmac_generate(struct carp_softc *sc, u_int32_t counter[2],
321     unsigned char md[20])
322 {
323 	SHA1_CTX sha1ctx;
324 
325 	/* fetch first half of inner hash */
326 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
327 
328 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
329 	SHA1Final(md, &sha1ctx);
330 
331 	/* outer hash */
332 	SHA1Init(&sha1ctx);
333 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
334 	SHA1Update(&sha1ctx, md, 20);
335 	SHA1Final(md, &sha1ctx);
336 }
337 
338 static int
339 carp_hmac_verify(struct carp_softc *sc, u_int32_t counter[2],
340     unsigned char md[20])
341 {
342 	unsigned char md2[20];
343 
344 	CARP_SCLOCK_ASSERT(sc);
345 
346 	carp_hmac_generate(sc, counter, md2);
347 
348 	return (bcmp(md, md2, sizeof(md2)));
349 }
350 
351 static void
352 carp_setroute(struct carp_softc *sc, int cmd)
353 {
354 	struct ifaddr *ifa;
355 	int s;
356 
357 	if (sc->sc_carpdev)
358 		CARP_SCLOCK_ASSERT(sc);
359 
360 	s = splnet();
361 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
362 		if (ifa->ifa_addr->sa_family == AF_INET &&
363 		    sc->sc_carpdev != NULL) {
364 			int count = carp_addrcount(
365 			    (struct carp_if *)sc->sc_carpdev->if_carp,
366 			    ifatoia(ifa), CARP_COUNT_MASTER);
367 
368 			if ((cmd == RTM_ADD && count == 1) ||
369 			    (cmd == RTM_DELETE && count == 0))
370 				rtinit(ifa, cmd, RTF_UP | RTF_HOST);
371 		}
372 #ifdef INET6
373 		if (ifa->ifa_addr->sa_family == AF_INET6) {
374 			if (cmd == RTM_ADD)
375 				in6_ifaddloop(ifa);
376 			else
377 				in6_ifremloop(ifa);
378 		}
379 #endif /* INET6 */
380 	}
381 	splx(s);
382 }
383 
384 static int
385 carp_clone_create(struct if_clone *ifc, int unit, caddr_t params)
386 {
387 
388 	struct carp_softc *sc;
389 	struct ifnet *ifp;
390 
391 	MALLOC(sc, struct carp_softc *, sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
392 	ifp = SC2IFP(sc) = if_alloc(IFT_ETHER);
393 	if (ifp == NULL) {
394 		FREE(sc, M_CARP);
395 		return (ENOSPC);
396 	}
397 
398 	sc->sc_flags_backup = 0;
399 	sc->sc_suppress = 0;
400 	sc->sc_advbase = CARP_DFLTINTV;
401 	sc->sc_vhid = -1;	/* required setting */
402 	sc->sc_advskew = 0;
403 	sc->sc_init_counter = 1;
404 	sc->sc_naddrs = sc->sc_naddrs6 = 0; /* M_ZERO? */
405 #ifdef INET6
406 	sc->sc_im6o.im6o_multicast_hlim = CARP_DFLTTL;
407 #endif
408 	sc->sc_imo.imo_membership = (struct in_multi **)malloc(
409 	    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
410 	    M_WAITOK);
411 	sc->sc_imo.imo_mfilters = NULL;
412 	sc->sc_imo.imo_max_memberships = IP_MIN_MEMBERSHIPS;
413 	sc->sc_imo.imo_multicast_vif = -1;
414 
415 	callout_init(&sc->sc_ad_tmo, CALLOUT_MPSAFE);
416 	callout_init(&sc->sc_md_tmo, CALLOUT_MPSAFE);
417 	callout_init(&sc->sc_md6_tmo, CALLOUT_MPSAFE);
418 
419 	ifp->if_softc = sc;
420 	if_initname(ifp, CARP_IFNAME, unit);
421 	ifp->if_mtu = ETHERMTU;
422 	ifp->if_flags = IFF_LOOPBACK;
423 	ifp->if_ioctl = carp_ioctl;
424 	ifp->if_output = carp_looutput;
425 	ifp->if_start = carp_start;
426 	ifp->if_type = IFT_CARP;
427 	ifp->if_snd.ifq_maxlen = ifqmaxlen;
428 	ifp->if_hdrlen = 0;
429 	if_attach(ifp);
430 	bpfattach(SC2IFP(sc), DLT_NULL, sizeof(u_int32_t));
431 	mtx_lock(&carp_mtx);
432 	LIST_INSERT_HEAD(&carpif_list, sc, sc_next);
433 	mtx_unlock(&carp_mtx);
434 	return (0);
435 }
436 
437 static void
438 carp_clone_destroy(struct ifnet *ifp)
439 {
440 	struct carp_softc *sc = ifp->if_softc;
441 
442 	if (sc->sc_carpdev)
443 		CARP_SCLOCK(sc);
444 	carpdetach(sc, 1);	/* Returns unlocked. */
445 
446 	mtx_lock(&carp_mtx);
447 	LIST_REMOVE(sc, sc_next);
448 	mtx_unlock(&carp_mtx);
449 	bpfdetach(ifp);
450 	if_detach(ifp);
451 	if_free_type(ifp, IFT_ETHER);
452 	free(sc->sc_imo.imo_membership, M_CARP);
453 	free(sc, M_CARP);
454 }
455 
456 /*
457  * This function can be called on CARP interface destroy path,
458  * and in case of the removal of the underlying interface as
459  * well. We differentiate these two cases. In the latter case
460  * we do not cleanup our multicast memberships, since they
461  * are already freed. Also, in the latter case we do not
462  * release the lock on return, because the function will be
463  * called once more, for another CARP instance on the same
464  * interface.
465  */
466 static void
467 carpdetach(struct carp_softc *sc, int unlock)
468 {
469 	struct carp_if *cif;
470 
471 	callout_stop(&sc->sc_ad_tmo);
472 	callout_stop(&sc->sc_md_tmo);
473 	callout_stop(&sc->sc_md6_tmo);
474 
475 	if (sc->sc_suppress)
476 		carp_suppress_preempt--;
477 	sc->sc_suppress = 0;
478 
479 	if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS)
480 		carp_suppress_preempt--;
481 	sc->sc_sendad_errors = 0;
482 
483 	carp_set_state(sc, INIT);
484 	SC2IFP(sc)->if_flags &= ~IFF_UP;
485 	carp_setrun(sc, 0);
486 	if (unlock)
487 		carp_multicast_cleanup(sc);
488 #ifdef INET6
489 	carp_multicast6_cleanup(sc);
490 #endif
491 
492 	if (sc->sc_carpdev != NULL) {
493 		cif = (struct carp_if *)sc->sc_carpdev->if_carp;
494 		CARP_LOCK_ASSERT(cif);
495 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
496 		if (!--cif->vhif_nvrs) {
497 			ifpromisc(sc->sc_carpdev, 0);
498 			sc->sc_carpdev->if_carp = NULL;
499 			CARP_LOCK_DESTROY(cif);
500 			FREE(cif, M_IFADDR);
501 		} else if (unlock)
502 			CARP_UNLOCK(cif);
503 		sc->sc_carpdev = NULL;
504 	}
505 }
506 
507 /* Detach an interface from the carp. */
508 static void
509 carp_ifdetach(void *arg __unused, struct ifnet *ifp)
510 {
511 	struct carp_if *cif = (struct carp_if *)ifp->if_carp;
512 	struct carp_softc *sc, *nextsc;
513 
514 	if (cif == NULL)
515 		return;
516 
517 	/*
518 	 * XXX: At the end of for() cycle the lock will be destroyed.
519 	 */
520 	CARP_LOCK(cif);
521 	for (sc = TAILQ_FIRST(&cif->vhif_vrs); sc; sc = nextsc) {
522 		nextsc = TAILQ_NEXT(sc, sc_list);
523 		carpdetach(sc, 0);
524 	}
525 }
526 
527 /*
528  * process input packet.
529  * we have rearranged checks order compared to the rfc,
530  * but it seems more efficient this way or not possible otherwise.
531  */
532 void
533 carp_input(struct mbuf *m, int hlen)
534 {
535 	struct ip *ip = mtod(m, struct ip *);
536 	struct carp_header *ch;
537 	int iplen, len;
538 
539 	carpstats.carps_ipackets++;
540 
541 	if (!carp_opts[CARPCTL_ALLOW]) {
542 		m_freem(m);
543 		return;
544 	}
545 
546 	/* check if received on a valid carp interface */
547 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
548 		carpstats.carps_badif++;
549 		CARP_LOG("carp_input: packet received on non-carp "
550 		    "interface: %s\n",
551 		    m->m_pkthdr.rcvif->if_xname);
552 		m_freem(m);
553 		return;
554 	}
555 
556 	/* verify that the IP TTL is 255.  */
557 	if (ip->ip_ttl != CARP_DFLTTL) {
558 		carpstats.carps_badttl++;
559 		CARP_LOG("carp_input: received ttl %d != 255i on %s\n",
560 		    ip->ip_ttl,
561 		    m->m_pkthdr.rcvif->if_xname);
562 		m_freem(m);
563 		return;
564 	}
565 
566 	iplen = ip->ip_hl << 2;
567 
568 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
569 		carpstats.carps_badlen++;
570 		CARP_LOG("carp_input: received len %zd < "
571 		    "sizeof(struct carp_header)\n",
572 		    m->m_len - sizeof(struct ip));
573 		m_freem(m);
574 		return;
575 	}
576 
577 	if (iplen + sizeof(*ch) < m->m_len) {
578 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
579 			carpstats.carps_hdrops++;
580 			CARP_LOG("carp_input: pullup failed\n");
581 			return;
582 		}
583 		ip = mtod(m, struct ip *);
584 	}
585 	ch = (struct carp_header *)((char *)ip + iplen);
586 
587 	/*
588 	 * verify that the received packet length is
589 	 * equal to the CARP header
590 	 */
591 	len = iplen + sizeof(*ch);
592 	if (len > m->m_pkthdr.len) {
593 		carpstats.carps_badlen++;
594 		CARP_LOG("carp_input: packet too short %d on %s\n",
595 		    m->m_pkthdr.len,
596 		    m->m_pkthdr.rcvif->if_xname);
597 		m_freem(m);
598 		return;
599 	}
600 
601 	if ((m = m_pullup(m, len)) == NULL) {
602 		carpstats.carps_hdrops++;
603 		return;
604 	}
605 	ip = mtod(m, struct ip *);
606 	ch = (struct carp_header *)((char *)ip + iplen);
607 
608 	/* verify the CARP checksum */
609 	m->m_data += iplen;
610 	if (carp_cksum(m, len - iplen)) {
611 		carpstats.carps_badsum++;
612 		CARP_LOG("carp_input: checksum failed on %s\n",
613 		    m->m_pkthdr.rcvif->if_xname);
614 		m_freem(m);
615 		return;
616 	}
617 	m->m_data -= iplen;
618 
619 	carp_input_c(m, ch, AF_INET);
620 }
621 
622 #ifdef INET6
623 int
624 carp6_input(struct mbuf **mp, int *offp, int proto)
625 {
626 	struct mbuf *m = *mp;
627 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
628 	struct carp_header *ch;
629 	u_int len;
630 
631 	carpstats.carps_ipackets6++;
632 
633 	if (!carp_opts[CARPCTL_ALLOW]) {
634 		m_freem(m);
635 		return (IPPROTO_DONE);
636 	}
637 
638 	/* check if received on a valid carp interface */
639 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
640 		carpstats.carps_badif++;
641 		CARP_LOG("carp6_input: packet received on non-carp "
642 		    "interface: %s\n",
643 		    m->m_pkthdr.rcvif->if_xname);
644 		m_freem(m);
645 		return (IPPROTO_DONE);
646 	}
647 
648 	/* verify that the IP TTL is 255 */
649 	if (ip6->ip6_hlim != CARP_DFLTTL) {
650 		carpstats.carps_badttl++;
651 		CARP_LOG("carp6_input: received ttl %d != 255 on %s\n",
652 		    ip6->ip6_hlim,
653 		    m->m_pkthdr.rcvif->if_xname);
654 		m_freem(m);
655 		return (IPPROTO_DONE);
656 	}
657 
658 	/* verify that we have a complete carp packet */
659 	len = m->m_len;
660 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
661 	if (ch == NULL) {
662 		carpstats.carps_badlen++;
663 		CARP_LOG("carp6_input: packet size %u too small\n", len);
664 		return (IPPROTO_DONE);
665 	}
666 
667 
668 	/* verify the CARP checksum */
669 	m->m_data += *offp;
670 	if (carp_cksum(m, sizeof(*ch))) {
671 		carpstats.carps_badsum++;
672 		CARP_LOG("carp6_input: checksum failed, on %s\n",
673 		    m->m_pkthdr.rcvif->if_xname);
674 		m_freem(m);
675 		return (IPPROTO_DONE);
676 	}
677 	m->m_data -= *offp;
678 
679 	carp_input_c(m, ch, AF_INET6);
680 	return (IPPROTO_DONE);
681 }
682 #endif /* INET6 */
683 
684 static void
685 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
686 {
687 	struct ifnet *ifp = m->m_pkthdr.rcvif;
688 	struct carp_softc *sc;
689 	u_int64_t tmp_counter;
690 	struct timeval sc_tv, ch_tv;
691 
692 	/* verify that the VHID is valid on the receiving interface */
693 	CARP_LOCK(ifp->if_carp);
694 	TAILQ_FOREACH(sc, &((struct carp_if *)ifp->if_carp)->vhif_vrs, sc_list)
695 		if (sc->sc_vhid == ch->carp_vhid)
696 			break;
697 
698 	if (!sc || !((SC2IFP(sc)->if_flags & IFF_UP) &&
699 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
700 		carpstats.carps_badvhid++;
701 		CARP_UNLOCK(ifp->if_carp);
702 		m_freem(m);
703 		return;
704 	}
705 
706 	getmicrotime(&SC2IFP(sc)->if_lastchange);
707 	SC2IFP(sc)->if_ipackets++;
708 	SC2IFP(sc)->if_ibytes += m->m_pkthdr.len;
709 
710 	if (bpf_peers_present(SC2IFP(sc)->if_bpf)) {
711 		struct ip *ip = mtod(m, struct ip *);
712 		uint32_t af1 = af;
713 
714 		/* BPF wants net byte order */
715 		ip->ip_len = htons(ip->ip_len + (ip->ip_hl << 2));
716 		ip->ip_off = htons(ip->ip_off);
717 		bpf_mtap2(SC2IFP(sc)->if_bpf, &af1, sizeof(af1), m);
718 	}
719 
720 	/* verify the CARP version. */
721 	if (ch->carp_version != CARP_VERSION) {
722 		carpstats.carps_badver++;
723 		SC2IFP(sc)->if_ierrors++;
724 		CARP_UNLOCK(ifp->if_carp);
725 		CARP_LOG("%s; invalid version %d\n",
726 		    SC2IFP(sc)->if_xname,
727 		    ch->carp_version);
728 		m_freem(m);
729 		return;
730 	}
731 
732 	/* verify the hash */
733 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
734 		carpstats.carps_badauth++;
735 		SC2IFP(sc)->if_ierrors++;
736 		CARP_UNLOCK(ifp->if_carp);
737 		CARP_LOG("%s: incorrect hash\n", SC2IFP(sc)->if_xname);
738 		m_freem(m);
739 		return;
740 	}
741 
742 	tmp_counter = ntohl(ch->carp_counter[0]);
743 	tmp_counter = tmp_counter<<32;
744 	tmp_counter += ntohl(ch->carp_counter[1]);
745 
746 	/* XXX Replay protection goes here */
747 
748 	sc->sc_init_counter = 0;
749 	sc->sc_counter = tmp_counter;
750 
751 	sc_tv.tv_sec = sc->sc_advbase;
752 	if (carp_suppress_preempt && sc->sc_advskew <  240)
753 		sc_tv.tv_usec = 240 * 1000000 / 256;
754 	else
755 		sc_tv.tv_usec = sc->sc_advskew * 1000000 / 256;
756 	ch_tv.tv_sec = ch->carp_advbase;
757 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
758 
759 	switch (sc->sc_state) {
760 	case INIT:
761 		break;
762 	case MASTER:
763 		/*
764 		 * If we receive an advertisement from a master who's going to
765 		 * be more frequent than us, go into BACKUP state.
766 		 */
767 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
768 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
769 			callout_stop(&sc->sc_ad_tmo);
770 			CARP_DEBUG("%s: MASTER -> BACKUP "
771 			   "(more frequent advertisement received)\n",
772 			   SC2IFP(sc)->if_xname);
773 			carp_set_state(sc, BACKUP);
774 			carp_setrun(sc, 0);
775 			carp_setroute(sc, RTM_DELETE);
776 		}
777 		break;
778 	case BACKUP:
779 		/*
780 		 * If we're pre-empting masters who advertise slower than us,
781 		 * and this one claims to be slower, treat him as down.
782 		 */
783 		if (carp_opts[CARPCTL_PREEMPT] &&
784 		    timevalcmp(&sc_tv, &ch_tv, <)) {
785 			CARP_DEBUG("%s: BACKUP -> MASTER "
786 			    "(preempting a slower master)\n",
787 			    SC2IFP(sc)->if_xname);
788 			carp_master_down_locked(sc);
789 			break;
790 		}
791 
792 		/*
793 		 *  If the master is going to advertise at such a low frequency
794 		 *  that he's guaranteed to time out, we'd might as well just
795 		 *  treat him as timed out now.
796 		 */
797 		sc_tv.tv_sec = sc->sc_advbase * 3;
798 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
799 			CARP_DEBUG("%s: BACKUP -> MASTER "
800 			    "(master timed out)\n",
801 			    SC2IFP(sc)->if_xname);
802 			carp_master_down_locked(sc);
803 			break;
804 		}
805 
806 		/*
807 		 * Otherwise, we reset the counter and wait for the next
808 		 * advertisement.
809 		 */
810 		carp_setrun(sc, af);
811 		break;
812 	}
813 
814 	CARP_UNLOCK(ifp->if_carp);
815 
816 	m_freem(m);
817 	return;
818 }
819 
820 static int
821 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
822 {
823 	struct m_tag *mtag;
824 	struct ifnet *ifp = SC2IFP(sc);
825 
826 	if (sc->sc_init_counter) {
827 		/* this could also be seconds since unix epoch */
828 		sc->sc_counter = arc4random();
829 		sc->sc_counter = sc->sc_counter << 32;
830 		sc->sc_counter += arc4random();
831 	} else
832 		sc->sc_counter++;
833 
834 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
835 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
836 
837 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
838 
839 	/* Tag packet for carp_output */
840 	mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct ifnet *), M_NOWAIT);
841 	if (mtag == NULL) {
842 		m_freem(m);
843 		SC2IFP(sc)->if_oerrors++;
844 		return (ENOMEM);
845 	}
846 	bcopy(&ifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *));
847 	m_tag_prepend(m, mtag);
848 
849 	return (0);
850 }
851 
852 static void
853 carp_send_ad_all(void)
854 {
855 	struct carp_softc *sc;
856 
857 	mtx_lock(&carp_mtx);
858 	LIST_FOREACH(sc, &carpif_list, sc_next) {
859 		if (sc->sc_carpdev == NULL)
860 			continue;
861 		CARP_SCLOCK(sc);
862 		if ((SC2IFP(sc)->if_flags & IFF_UP) &&
863 		    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING) &&
864 		     sc->sc_state == MASTER)
865 			carp_send_ad_locked(sc);
866 		CARP_SCUNLOCK(sc);
867 	}
868 	mtx_unlock(&carp_mtx);
869 }
870 
871 static void
872 carp_send_ad(void *v)
873 {
874 	struct carp_softc *sc = v;
875 
876 	CARP_SCLOCK(sc);
877 	carp_send_ad_locked(sc);
878 	CARP_SCUNLOCK(sc);
879 }
880 
881 static void
882 carp_send_ad_locked(struct carp_softc *sc)
883 {
884 	struct carp_header ch;
885 	struct timeval tv;
886 	struct carp_header *ch_ptr;
887 	struct mbuf *m;
888 	int len, advbase, advskew;
889 
890 	CARP_SCLOCK_ASSERT(sc);
891 
892 	/* bow out if we've lost our UPness or RUNNINGuiness */
893 	if (!((SC2IFP(sc)->if_flags & IFF_UP) &&
894 	    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING))) {
895 		advbase = 255;
896 		advskew = 255;
897 	} else {
898 		advbase = sc->sc_advbase;
899 		if (!carp_suppress_preempt || sc->sc_advskew > 240)
900 			advskew = sc->sc_advskew;
901 		else
902 			advskew = 240;
903 		tv.tv_sec = advbase;
904 		tv.tv_usec = advskew * 1000000 / 256;
905 	}
906 
907 	ch.carp_version = CARP_VERSION;
908 	ch.carp_type = CARP_ADVERTISEMENT;
909 	ch.carp_vhid = sc->sc_vhid;
910 	ch.carp_advbase = advbase;
911 	ch.carp_advskew = advskew;
912 	ch.carp_authlen = 7;	/* XXX DEFINE */
913 	ch.carp_pad1 = 0;	/* must be zero */
914 	ch.carp_cksum = 0;
915 
916 #ifdef INET
917 	if (sc->sc_ia) {
918 		struct ip *ip;
919 
920 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
921 		if (m == NULL) {
922 			SC2IFP(sc)->if_oerrors++;
923 			carpstats.carps_onomem++;
924 			/* XXX maybe less ? */
925 			if (advbase != 255 || advskew != 255)
926 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
927 				    carp_send_ad, sc);
928 			return;
929 		}
930 		len = sizeof(*ip) + sizeof(ch);
931 		m->m_pkthdr.len = len;
932 		m->m_pkthdr.rcvif = NULL;
933 		m->m_len = len;
934 		MH_ALIGN(m, m->m_len);
935 		m->m_flags |= M_MCAST;
936 		ip = mtod(m, struct ip *);
937 		ip->ip_v = IPVERSION;
938 		ip->ip_hl = sizeof(*ip) >> 2;
939 		ip->ip_tos = IPTOS_LOWDELAY;
940 		ip->ip_len = len;
941 		ip->ip_id = ip_newid();
942 		ip->ip_off = IP_DF;
943 		ip->ip_ttl = CARP_DFLTTL;
944 		ip->ip_p = IPPROTO_CARP;
945 		ip->ip_sum = 0;
946 		ip->ip_src.s_addr = sc->sc_ia->ia_addr.sin_addr.s_addr;
947 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
948 
949 		ch_ptr = (struct carp_header *)(&ip[1]);
950 		bcopy(&ch, ch_ptr, sizeof(ch));
951 		if (carp_prepare_ad(m, sc, ch_ptr))
952 			return;
953 
954 		m->m_data += sizeof(*ip);
955 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip));
956 		m->m_data -= sizeof(*ip);
957 
958 		getmicrotime(&SC2IFP(sc)->if_lastchange);
959 		SC2IFP(sc)->if_opackets++;
960 		SC2IFP(sc)->if_obytes += len;
961 		carpstats.carps_opackets++;
962 
963 		if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)) {
964 			SC2IFP(sc)->if_oerrors++;
965 			if (sc->sc_sendad_errors < INT_MAX)
966 				sc->sc_sendad_errors++;
967 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
968 				carp_suppress_preempt++;
969 				if (carp_suppress_preempt == 1) {
970 					CARP_SCUNLOCK(sc);
971 					carp_send_ad_all();
972 					CARP_SCLOCK(sc);
973 				}
974 			}
975 			sc->sc_sendad_success = 0;
976 		} else {
977 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
978 				if (++sc->sc_sendad_success >=
979 				    CARP_SENDAD_MIN_SUCCESS) {
980 					carp_suppress_preempt--;
981 					sc->sc_sendad_errors = 0;
982 				}
983 			} else
984 				sc->sc_sendad_errors = 0;
985 		}
986 	}
987 #endif /* INET */
988 #ifdef INET6
989 	if (sc->sc_ia6) {
990 		struct ip6_hdr *ip6;
991 
992 		MGETHDR(m, M_DONTWAIT, MT_HEADER);
993 		if (m == NULL) {
994 			SC2IFP(sc)->if_oerrors++;
995 			carpstats.carps_onomem++;
996 			/* XXX maybe less ? */
997 			if (advbase != 255 || advskew != 255)
998 				callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
999 				    carp_send_ad, sc);
1000 			return;
1001 		}
1002 		len = sizeof(*ip6) + sizeof(ch);
1003 		m->m_pkthdr.len = len;
1004 		m->m_pkthdr.rcvif = NULL;
1005 		m->m_len = len;
1006 		MH_ALIGN(m, m->m_len);
1007 		m->m_flags |= M_MCAST;
1008 		ip6 = mtod(m, struct ip6_hdr *);
1009 		bzero(ip6, sizeof(*ip6));
1010 		ip6->ip6_vfc |= IPV6_VERSION;
1011 		ip6->ip6_hlim = CARP_DFLTTL;
1012 		ip6->ip6_nxt = IPPROTO_CARP;
1013 		bcopy(&sc->sc_ia6->ia_addr.sin6_addr, &ip6->ip6_src,
1014 		    sizeof(struct in6_addr));
1015 		/* set the multicast destination */
1016 
1017 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1018 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1019 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1020 			SC2IFP(sc)->if_oerrors++;
1021 			m_freem(m);
1022 			CARP_LOG("%s: in6_setscope failed\n", __func__);
1023 			return;
1024 		}
1025 
1026 		ch_ptr = (struct carp_header *)(&ip6[1]);
1027 		bcopy(&ch, ch_ptr, sizeof(ch));
1028 		if (carp_prepare_ad(m, sc, ch_ptr))
1029 			return;
1030 
1031 		m->m_data += sizeof(*ip6);
1032 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip6));
1033 		m->m_data -= sizeof(*ip6);
1034 
1035 		getmicrotime(&SC2IFP(sc)->if_lastchange);
1036 		SC2IFP(sc)->if_opackets++;
1037 		SC2IFP(sc)->if_obytes += len;
1038 		carpstats.carps_opackets6++;
1039 
1040 		if (ip6_output(m, NULL, NULL, 0, &sc->sc_im6o, NULL, NULL)) {
1041 			SC2IFP(sc)->if_oerrors++;
1042 			if (sc->sc_sendad_errors < INT_MAX)
1043 				sc->sc_sendad_errors++;
1044 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
1045 				carp_suppress_preempt++;
1046 				if (carp_suppress_preempt == 1) {
1047 					CARP_SCUNLOCK(sc);
1048 					carp_send_ad_all();
1049 					CARP_SCLOCK(sc);
1050 				}
1051 			}
1052 			sc->sc_sendad_success = 0;
1053 		} else {
1054 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
1055 				if (++sc->sc_sendad_success >=
1056 				    CARP_SENDAD_MIN_SUCCESS) {
1057 					carp_suppress_preempt--;
1058 					sc->sc_sendad_errors = 0;
1059 				}
1060 			} else
1061 				sc->sc_sendad_errors = 0;
1062 		}
1063 	}
1064 #endif /* INET6 */
1065 
1066 	if (advbase != 255 || advskew != 255)
1067 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1068 		    carp_send_ad, sc);
1069 
1070 }
1071 
1072 /*
1073  * Broadcast a gratuitous ARP request containing
1074  * the virtual router MAC address for each IP address
1075  * associated with the virtual router.
1076  */
1077 static void
1078 carp_send_arp(struct carp_softc *sc)
1079 {
1080 	struct ifaddr *ifa;
1081 
1082 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1083 
1084 		if (ifa->ifa_addr->sa_family != AF_INET)
1085 			continue;
1086 
1087 /*		arprequest(sc->sc_carpdev, &in, &in, IF_LLADDR(sc->sc_ifp)); */
1088 		arp_ifinit2(sc->sc_carpdev, ifa, IF_LLADDR(sc->sc_ifp));
1089 
1090 		DELAY(1000);	/* XXX */
1091 	}
1092 }
1093 
1094 #ifdef INET6
1095 static void
1096 carp_send_na(struct carp_softc *sc)
1097 {
1098 	struct ifaddr *ifa;
1099 	struct in6_addr *in6;
1100 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1101 
1102 	TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1103 
1104 		if (ifa->ifa_addr->sa_family != AF_INET6)
1105 			continue;
1106 
1107 		in6 = &ifatoia6(ifa)->ia_addr.sin6_addr;
1108 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1109 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1110 		DELAY(1000);	/* XXX */
1111 	}
1112 }
1113 #endif /* INET6 */
1114 
1115 static int
1116 carp_addrcount(struct carp_if *cif, struct in_ifaddr *ia, int type)
1117 {
1118 	struct carp_softc *vh;
1119 	struct ifaddr *ifa;
1120 	int count = 0;
1121 
1122 	CARP_LOCK_ASSERT(cif);
1123 
1124 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1125 		if ((type == CARP_COUNT_RUNNING &&
1126 		    (SC2IFP(vh)->if_flags & IFF_UP) &&
1127 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) ||
1128 		    (type == CARP_COUNT_MASTER && vh->sc_state == MASTER)) {
1129 			TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1130 			    ifa_list) {
1131 				if (ifa->ifa_addr->sa_family == AF_INET &&
1132 				    ia->ia_addr.sin_addr.s_addr ==
1133 				    ifatoia(ifa)->ia_addr.sin_addr.s_addr)
1134 					count++;
1135 			}
1136 		}
1137 	}
1138 	return (count);
1139 }
1140 
1141 int
1142 carp_iamatch(void *v, struct in_ifaddr *ia,
1143     struct in_addr *isaddr, u_int8_t **enaddr)
1144 {
1145 	struct carp_if *cif = v;
1146 	struct carp_softc *vh;
1147 	int index, count = 0;
1148 	struct ifaddr *ifa;
1149 
1150 	CARP_LOCK(cif);
1151 
1152 	if (carp_opts[CARPCTL_ARPBALANCE]) {
1153 		/*
1154 		 * XXX proof of concept implementation.
1155 		 * We use the source ip to decide which virtual host should
1156 		 * handle the request. If we're master of that virtual host,
1157 		 * then we respond, otherwise, just drop the arp packet on
1158 		 * the floor.
1159 		 */
1160 		count = carp_addrcount(cif, ia, CARP_COUNT_RUNNING);
1161 		if (count == 0) {
1162 			/* should never reach this */
1163 			CARP_UNLOCK(cif);
1164 			return (0);
1165 		}
1166 
1167 		/* this should be a hash, like pf_hash() */
1168 		index = ntohl(isaddr->s_addr) % count;
1169 		count = 0;
1170 
1171 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1172 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1173 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING)) {
1174 				TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist,
1175 				    ifa_list) {
1176 					if (ifa->ifa_addr->sa_family ==
1177 					    AF_INET &&
1178 					    ia->ia_addr.sin_addr.s_addr ==
1179 					    ifatoia(ifa)->ia_addr.sin_addr.s_addr) {
1180 						if (count == index) {
1181 							if (vh->sc_state ==
1182 							    MASTER) {
1183 								*enaddr = IF_LLADDR(vh->sc_ifp);
1184 								CARP_UNLOCK(cif);
1185 								return (1);
1186 							} else {
1187 								CARP_UNLOCK(cif);
1188 								return (0);
1189 							}
1190 						}
1191 						count++;
1192 					}
1193 				}
1194 			}
1195 		}
1196 	} else {
1197 		TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1198 			if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1199 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1200 			    ia->ia_ifp == SC2IFP(vh) &&
1201 			    vh->sc_state == MASTER) {
1202 				*enaddr = IF_LLADDR(vh->sc_ifp);
1203 				CARP_UNLOCK(cif);
1204 				return (1);
1205 			}
1206 		}
1207 	}
1208 	CARP_UNLOCK(cif);
1209 	return (0);
1210 }
1211 
1212 #ifdef INET6
1213 struct ifaddr *
1214 carp_iamatch6(void *v, struct in6_addr *taddr)
1215 {
1216 	struct carp_if *cif = v;
1217 	struct carp_softc *vh;
1218 	struct ifaddr *ifa;
1219 
1220 	CARP_LOCK(cif);
1221 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1222 		TAILQ_FOREACH(ifa, &SC2IFP(vh)->if_addrlist, ifa_list) {
1223 			if (IN6_ARE_ADDR_EQUAL(taddr,
1224 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1225  			    (SC2IFP(vh)->if_flags & IFF_UP) &&
1226 			    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1227 			    vh->sc_state == MASTER) {
1228 			    	CARP_UNLOCK(cif);
1229 				return (ifa);
1230 			}
1231 		}
1232 	}
1233 	CARP_UNLOCK(cif);
1234 
1235 	return (NULL);
1236 }
1237 
1238 void *
1239 carp_macmatch6(void *v, struct mbuf *m, const struct in6_addr *taddr)
1240 {
1241 	struct m_tag *mtag;
1242 	struct carp_if *cif = v;
1243 	struct carp_softc *sc;
1244 	struct ifaddr *ifa;
1245 
1246 	CARP_LOCK(cif);
1247 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
1248 		TAILQ_FOREACH(ifa, &SC2IFP(sc)->if_addrlist, ifa_list) {
1249 			if (IN6_ARE_ADDR_EQUAL(taddr,
1250 			    &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1251  			    (SC2IFP(sc)->if_flags & IFF_UP) &&
1252 			    (SC2IFP(sc)->if_drv_flags & IFF_DRV_RUNNING)) {
1253 				struct ifnet *ifp = SC2IFP(sc);
1254 				mtag = m_tag_get(PACKET_TAG_CARP,
1255 				    sizeof(struct ifnet *), M_NOWAIT);
1256 				if (mtag == NULL) {
1257 					/* better a bit than nothing */
1258 					CARP_UNLOCK(cif);
1259 					return (IF_LLADDR(sc->sc_ifp));
1260 				}
1261 				bcopy(&ifp, (caddr_t)(mtag + 1),
1262 				    sizeof(struct ifnet *));
1263 				m_tag_prepend(m, mtag);
1264 
1265 				CARP_UNLOCK(cif);
1266 				return (IF_LLADDR(sc->sc_ifp));
1267 			}
1268 		}
1269 	}
1270 	CARP_UNLOCK(cif);
1271 
1272 	return (NULL);
1273 }
1274 #endif
1275 
1276 struct ifnet *
1277 carp_forus(void *v, void *dhost)
1278 {
1279 	struct carp_if *cif = v;
1280 	struct carp_softc *vh;
1281 	u_int8_t *ena = dhost;
1282 
1283 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1284 		return (NULL);
1285 
1286 	CARP_LOCK(cif);
1287 	TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list)
1288 		if ((SC2IFP(vh)->if_flags & IFF_UP) &&
1289 		    (SC2IFP(vh)->if_drv_flags & IFF_DRV_RUNNING) &&
1290 		    vh->sc_state == MASTER &&
1291 		    !bcmp(dhost, IF_LLADDR(vh->sc_ifp), ETHER_ADDR_LEN)) {
1292 		    	CARP_UNLOCK(cif);
1293 			return (SC2IFP(vh));
1294 		}
1295 
1296     	CARP_UNLOCK(cif);
1297 	return (NULL);
1298 }
1299 
1300 static void
1301 carp_master_down(void *v)
1302 {
1303 	struct carp_softc *sc = v;
1304 
1305 	CARP_SCLOCK(sc);
1306 	carp_master_down_locked(sc);
1307 	CARP_SCUNLOCK(sc);
1308 }
1309 
1310 static void
1311 carp_master_down_locked(struct carp_softc *sc)
1312 {
1313 	if (sc->sc_carpdev)
1314 		CARP_SCLOCK_ASSERT(sc);
1315 
1316 	switch (sc->sc_state) {
1317 	case INIT:
1318 		printf("%s: master_down event in INIT state\n",
1319 		    SC2IFP(sc)->if_xname);
1320 		break;
1321 	case MASTER:
1322 		break;
1323 	case BACKUP:
1324 		carp_set_state(sc, MASTER);
1325 		carp_send_ad_locked(sc);
1326 		carp_send_arp(sc);
1327 #ifdef INET6
1328 		carp_send_na(sc);
1329 #endif /* INET6 */
1330 		carp_setrun(sc, 0);
1331 		carp_setroute(sc, RTM_ADD);
1332 		break;
1333 	}
1334 }
1335 
1336 /*
1337  * When in backup state, af indicates whether to reset the master down timer
1338  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1339  */
1340 static void
1341 carp_setrun(struct carp_softc *sc, sa_family_t af)
1342 {
1343 	struct timeval tv;
1344 
1345 	if (sc->sc_carpdev == NULL) {
1346 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1347 		carp_set_state(sc, INIT);
1348 		return;
1349 	} else
1350 		CARP_SCLOCK_ASSERT(sc);
1351 
1352 	if (SC2IFP(sc)->if_flags & IFF_UP &&
1353 	    sc->sc_vhid > 0 && (sc->sc_naddrs || sc->sc_naddrs6))
1354 		SC2IFP(sc)->if_drv_flags |= IFF_DRV_RUNNING;
1355 	else {
1356 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1357 		carp_setroute(sc, RTM_DELETE);
1358 		return;
1359 	}
1360 
1361 	switch (sc->sc_state) {
1362 	case INIT:
1363 		if (carp_opts[CARPCTL_PREEMPT] && !carp_suppress_preempt) {
1364 			carp_send_ad_locked(sc);
1365 			carp_send_arp(sc);
1366 #ifdef INET6
1367 			carp_send_na(sc);
1368 #endif /* INET6 */
1369 			CARP_DEBUG("%s: INIT -> MASTER (preempting)\n",
1370 			    SC2IFP(sc)->if_xname);
1371 			carp_set_state(sc, MASTER);
1372 			carp_setroute(sc, RTM_ADD);
1373 		} else {
1374 			CARP_DEBUG("%s: INIT -> BACKUP\n", SC2IFP(sc)->if_xname);
1375 			carp_set_state(sc, BACKUP);
1376 			carp_setroute(sc, RTM_DELETE);
1377 			carp_setrun(sc, 0);
1378 		}
1379 		break;
1380 	case BACKUP:
1381 		callout_stop(&sc->sc_ad_tmo);
1382 		tv.tv_sec = 3 * sc->sc_advbase;
1383 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1384 		switch (af) {
1385 #ifdef INET
1386 		case AF_INET:
1387 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1388 			    carp_master_down, sc);
1389 			break;
1390 #endif /* INET */
1391 #ifdef INET6
1392 		case AF_INET6:
1393 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1394 			    carp_master_down, sc);
1395 			break;
1396 #endif /* INET6 */
1397 		default:
1398 			if (sc->sc_naddrs)
1399 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1400 				    carp_master_down, sc);
1401 			if (sc->sc_naddrs6)
1402 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1403 				    carp_master_down, sc);
1404 			break;
1405 		}
1406 		break;
1407 	case MASTER:
1408 		tv.tv_sec = sc->sc_advbase;
1409 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1410 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1411 		    carp_send_ad, sc);
1412 		break;
1413 	}
1414 }
1415 
1416 static void
1417 carp_multicast_cleanup(struct carp_softc *sc)
1418 {
1419 	struct ip_moptions *imo = &sc->sc_imo;
1420 	u_int16_t n = imo->imo_num_memberships;
1421 
1422 	/* Clean up our own multicast memberships */
1423 	while (n-- > 0) {
1424 		if (imo->imo_membership[n] != NULL) {
1425 			in_delmulti(imo->imo_membership[n]);
1426 			imo->imo_membership[n] = NULL;
1427 		}
1428 	}
1429 	KASSERT(imo->imo_mfilters == NULL,
1430 	   ("%s: imo_mfilters != NULL", __func__));
1431 	imo->imo_num_memberships = 0;
1432 	imo->imo_multicast_ifp = NULL;
1433 }
1434 
1435 #ifdef INET6
1436 static void
1437 carp_multicast6_cleanup(struct carp_softc *sc)
1438 {
1439 	struct ip6_moptions *im6o = &sc->sc_im6o;
1440 
1441 	while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1442 		struct in6_multi_mship *imm =
1443 		    LIST_FIRST(&im6o->im6o_memberships);
1444 
1445 		LIST_REMOVE(imm, i6mm_chain);
1446 		in6_leavegroup(imm);
1447 	}
1448 	im6o->im6o_multicast_ifp = NULL;
1449 }
1450 #endif
1451 
1452 static int
1453 carp_set_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1454 {
1455 	struct ifnet *ifp;
1456 	struct carp_if *cif;
1457 	struct in_ifaddr *ia, *ia_if;
1458 	struct ip_moptions *imo = &sc->sc_imo;
1459 	struct in_addr addr;
1460 	u_long iaddr = htonl(sin->sin_addr.s_addr);
1461 	int own, error;
1462 
1463 	if (sin->sin_addr.s_addr == 0) {
1464 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1465 			carp_set_state(sc, INIT);
1466 		if (sc->sc_naddrs)
1467 			SC2IFP(sc)->if_flags |= IFF_UP;
1468 		if (sc->sc_carpdev)
1469 			CARP_SCLOCK(sc);
1470 		carp_setrun(sc, 0);
1471 		if (sc->sc_carpdev)
1472 			CARP_SCUNLOCK(sc);
1473 		return (0);
1474 	}
1475 
1476 	/* we have to do it by hands to check we won't match on us */
1477 	ia_if = NULL; own = 0;
1478 	TAILQ_FOREACH(ia, &V_in_ifaddrhead, ia_link) {
1479 		/* and, yeah, we need a multicast-capable iface too */
1480 		if (ia->ia_ifp != SC2IFP(sc) &&
1481 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1482 		    (iaddr & ia->ia_subnetmask) == ia->ia_subnet) {
1483 			if (!ia_if)
1484 				ia_if = ia;
1485 			if (sin->sin_addr.s_addr ==
1486 			    ia->ia_addr.sin_addr.s_addr)
1487 				own++;
1488 		}
1489 	}
1490 
1491 	if (!ia_if)
1492 		return (EADDRNOTAVAIL);
1493 
1494 	ia = ia_if;
1495 	ifp = ia->ia_ifp;
1496 
1497 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1498 	    (imo->imo_multicast_ifp && imo->imo_multicast_ifp != ifp))
1499 		return (EADDRNOTAVAIL);
1500 
1501 	if (imo->imo_num_memberships == 0) {
1502 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1503 		if ((imo->imo_membership[0] = in_addmulti(&addr, ifp)) == NULL)
1504 			return (ENOBUFS);
1505 		imo->imo_num_memberships++;
1506 		imo->imo_multicast_ifp = ifp;
1507 		imo->imo_multicast_ttl = CARP_DFLTTL;
1508 		imo->imo_multicast_loop = 0;
1509 	}
1510 
1511 	if (!ifp->if_carp) {
1512 
1513 		MALLOC(cif, struct carp_if *, sizeof(*cif), M_CARP,
1514 		    M_WAITOK|M_ZERO);
1515 		if (!cif) {
1516 			error = ENOBUFS;
1517 			goto cleanup;
1518 		}
1519 		if ((error = ifpromisc(ifp, 1))) {
1520 			FREE(cif, M_CARP);
1521 			goto cleanup;
1522 		}
1523 
1524 		CARP_LOCK_INIT(cif);
1525 		CARP_LOCK(cif);
1526 		cif->vhif_ifp = ifp;
1527 		TAILQ_INIT(&cif->vhif_vrs);
1528 		ifp->if_carp = cif;
1529 
1530 	} else {
1531 		struct carp_softc *vr;
1532 
1533 		cif = (struct carp_if *)ifp->if_carp;
1534 		CARP_LOCK(cif);
1535 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1536 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1537 				CARP_UNLOCK(cif);
1538 				error = EEXIST;
1539 				goto cleanup;
1540 			}
1541 	}
1542 	sc->sc_ia = ia;
1543 	sc->sc_carpdev = ifp;
1544 
1545 	{ /* XXX prevent endless loop if already in queue */
1546 	struct carp_softc *vr, *after = NULL;
1547 	int myself = 0;
1548 	cif = (struct carp_if *)ifp->if_carp;
1549 
1550 	/* XXX: cif should not change, right? So we still hold the lock */
1551 	CARP_LOCK_ASSERT(cif);
1552 
1553 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1554 		if (vr == sc)
1555 			myself = 1;
1556 		if (vr->sc_vhid < sc->sc_vhid)
1557 			after = vr;
1558 	}
1559 
1560 	if (!myself) {
1561 		/* We're trying to keep things in order */
1562 		if (after == NULL) {
1563 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1564 		} else {
1565 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1566 		}
1567 		cif->vhif_nvrs++;
1568 	}
1569 	}
1570 
1571 	sc->sc_naddrs++;
1572 	SC2IFP(sc)->if_flags |= IFF_UP;
1573 	if (own)
1574 		sc->sc_advskew = 0;
1575 	carp_sc_state_locked(sc);
1576 	carp_setrun(sc, 0);
1577 
1578 	CARP_UNLOCK(cif);
1579 
1580 	return (0);
1581 
1582 cleanup:
1583 	in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1584 	return (error);
1585 }
1586 
1587 static int
1588 carp_del_addr(struct carp_softc *sc, struct sockaddr_in *sin)
1589 {
1590 	int error = 0;
1591 
1592 	if (!--sc->sc_naddrs) {
1593 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1594 		struct ip_moptions *imo = &sc->sc_imo;
1595 
1596 		CARP_LOCK(cif);
1597 		callout_stop(&sc->sc_ad_tmo);
1598 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1599 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1600 		sc->sc_vhid = -1;
1601 		in_delmulti(imo->imo_membership[--imo->imo_num_memberships]);
1602 		imo->imo_multicast_ifp = NULL;
1603 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1604 		if (!--cif->vhif_nvrs) {
1605 			sc->sc_carpdev->if_carp = NULL;
1606 			CARP_LOCK_DESTROY(cif);
1607 			FREE(cif, M_IFADDR);
1608 		} else {
1609 			CARP_UNLOCK(cif);
1610 		}
1611 	}
1612 
1613 	return (error);
1614 }
1615 
1616 #ifdef INET6
1617 static int
1618 carp_set_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1619 {
1620 	struct ifnet *ifp;
1621 	struct carp_if *cif;
1622 	struct in6_ifaddr *ia, *ia_if;
1623 	struct ip6_moptions *im6o = &sc->sc_im6o;
1624 	struct in6_multi_mship *imm;
1625 	struct in6_addr in6;
1626 	int own, error;
1627 
1628 	if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
1629 		if (!(SC2IFP(sc)->if_flags & IFF_UP))
1630 			carp_set_state(sc, INIT);
1631 		if (sc->sc_naddrs6)
1632 			SC2IFP(sc)->if_flags |= IFF_UP;
1633 		if (sc->sc_carpdev)
1634 			CARP_SCLOCK(sc);
1635 		carp_setrun(sc, 0);
1636 		if (sc->sc_carpdev)
1637 			CARP_SCUNLOCK(sc);
1638 		return (0);
1639 	}
1640 
1641 	/* we have to do it by hands to check we won't match on us */
1642 	ia_if = NULL; own = 0;
1643 	for (ia = V_in6_ifaddr; ia; ia = ia->ia_next) {
1644 		int i;
1645 
1646 		for (i = 0; i < 4; i++) {
1647 			if ((sin6->sin6_addr.s6_addr32[i] &
1648 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]) !=
1649 			    (ia->ia_addr.sin6_addr.s6_addr32[i] &
1650 			    ia->ia_prefixmask.sin6_addr.s6_addr32[i]))
1651 				break;
1652 		}
1653 		/* and, yeah, we need a multicast-capable iface too */
1654 		if (ia->ia_ifp != SC2IFP(sc) &&
1655 		    (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1656 		    (i == 4)) {
1657 			if (!ia_if)
1658 				ia_if = ia;
1659 			if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr,
1660 			    &ia->ia_addr.sin6_addr))
1661 				own++;
1662 		}
1663 	}
1664 
1665 	if (!ia_if)
1666 		return (EADDRNOTAVAIL);
1667 	ia = ia_if;
1668 	ifp = ia->ia_ifp;
1669 
1670 	if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1671 	    (im6o->im6o_multicast_ifp && im6o->im6o_multicast_ifp != ifp))
1672 		return (EADDRNOTAVAIL);
1673 
1674 	if (!sc->sc_naddrs6) {
1675 		im6o->im6o_multicast_ifp = ifp;
1676 
1677 		/* join CARP multicast address */
1678 		bzero(&in6, sizeof(in6));
1679 		in6.s6_addr16[0] = htons(0xff02);
1680 		in6.s6_addr8[15] = 0x12;
1681 		if (in6_setscope(&in6, ifp, NULL) != 0)
1682 			goto cleanup;
1683 		if ((imm = in6_joingroup(ifp, &in6, &error, 0)) == NULL)
1684 			goto cleanup;
1685 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
1686 
1687 		/* join solicited multicast address */
1688 		bzero(&in6, sizeof(in6));
1689 		in6.s6_addr16[0] = htons(0xff02);
1690 		in6.s6_addr32[1] = 0;
1691 		in6.s6_addr32[2] = htonl(1);
1692 		in6.s6_addr32[3] = sin6->sin6_addr.s6_addr32[3];
1693 		in6.s6_addr8[12] = 0xff;
1694 		if (in6_setscope(&in6, ifp, NULL) != 0)
1695 			goto cleanup;
1696 		if ((imm = in6_joingroup(ifp, &in6, &error, 0)) == NULL)
1697 			goto cleanup;
1698 		LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
1699 	}
1700 
1701 	if (!ifp->if_carp) {
1702 		MALLOC(cif, struct carp_if *, sizeof(*cif), M_CARP,
1703 		    M_WAITOK|M_ZERO);
1704 		if (!cif) {
1705 			error = ENOBUFS;
1706 			goto cleanup;
1707 		}
1708 		if ((error = ifpromisc(ifp, 1))) {
1709 			FREE(cif, M_CARP);
1710 			goto cleanup;
1711 		}
1712 
1713 		CARP_LOCK_INIT(cif);
1714 		CARP_LOCK(cif);
1715 		cif->vhif_ifp = ifp;
1716 		TAILQ_INIT(&cif->vhif_vrs);
1717 		ifp->if_carp = cif;
1718 
1719 	} else {
1720 		struct carp_softc *vr;
1721 
1722 		cif = (struct carp_if *)ifp->if_carp;
1723 		CARP_LOCK(cif);
1724 		TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1725 			if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1726 				CARP_UNLOCK(cif);
1727 				error = EINVAL;
1728 				goto cleanup;
1729 			}
1730 	}
1731 	sc->sc_ia6 = ia;
1732 	sc->sc_carpdev = ifp;
1733 
1734 	{ /* XXX prevent endless loop if already in queue */
1735 	struct carp_softc *vr, *after = NULL;
1736 	int myself = 0;
1737 	cif = (struct carp_if *)ifp->if_carp;
1738 	CARP_LOCK_ASSERT(cif);
1739 
1740 	TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1741 		if (vr == sc)
1742 			myself = 1;
1743 		if (vr->sc_vhid < sc->sc_vhid)
1744 			after = vr;
1745 	}
1746 
1747 	if (!myself) {
1748 		/* We're trying to keep things in order */
1749 		if (after == NULL) {
1750 			TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1751 		} else {
1752 			TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1753 		}
1754 		cif->vhif_nvrs++;
1755 	}
1756 	}
1757 
1758 	sc->sc_naddrs6++;
1759 	SC2IFP(sc)->if_flags |= IFF_UP;
1760 	if (own)
1761 		sc->sc_advskew = 0;
1762 	carp_sc_state_locked(sc);
1763 	carp_setrun(sc, 0);
1764 
1765 	CARP_UNLOCK(cif);
1766 
1767 	return (0);
1768 
1769 cleanup:
1770 	/* clean up multicast memberships */
1771 	if (!sc->sc_naddrs6) {
1772 		while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1773 			imm = LIST_FIRST(&im6o->im6o_memberships);
1774 			LIST_REMOVE(imm, i6mm_chain);
1775 			in6_leavegroup(imm);
1776 		}
1777 	}
1778 	return (error);
1779 }
1780 
1781 static int
1782 carp_del_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1783 {
1784 	int error = 0;
1785 
1786 	if (!--sc->sc_naddrs6) {
1787 		struct carp_if *cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1788 		struct ip6_moptions *im6o = &sc->sc_im6o;
1789 
1790 		CARP_LOCK(cif);
1791 		callout_stop(&sc->sc_ad_tmo);
1792 		SC2IFP(sc)->if_flags &= ~IFF_UP;
1793 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
1794 		sc->sc_vhid = -1;
1795 		while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1796 			struct in6_multi_mship *imm =
1797 			    LIST_FIRST(&im6o->im6o_memberships);
1798 
1799 			LIST_REMOVE(imm, i6mm_chain);
1800 			in6_leavegroup(imm);
1801 		}
1802 		im6o->im6o_multicast_ifp = NULL;
1803 		TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1804 		if (!--cif->vhif_nvrs) {
1805 			CARP_LOCK_DESTROY(cif);
1806 			sc->sc_carpdev->if_carp = NULL;
1807 			FREE(cif, M_IFADDR);
1808 		} else
1809 			CARP_UNLOCK(cif);
1810 	}
1811 
1812 	return (error);
1813 }
1814 #endif /* INET6 */
1815 
1816 static int
1817 carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr)
1818 {
1819 	struct carp_softc *sc = ifp->if_softc, *vr;
1820 	struct carpreq carpr;
1821 	struct ifaddr *ifa;
1822 	struct ifreq *ifr;
1823 	struct ifaliasreq *ifra;
1824 	int locked = 0, error = 0;
1825 
1826 	ifa = (struct ifaddr *)addr;
1827 	ifra = (struct ifaliasreq *)addr;
1828 	ifr = (struct ifreq *)addr;
1829 
1830 	switch (cmd) {
1831 	case SIOCSIFADDR:
1832 		switch (ifa->ifa_addr->sa_family) {
1833 #ifdef INET
1834 		case AF_INET:
1835 			SC2IFP(sc)->if_flags |= IFF_UP;
1836 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1837 			    sizeof(struct sockaddr));
1838 			error = carp_set_addr(sc, satosin(ifa->ifa_addr));
1839 			break;
1840 #endif /* INET */
1841 #ifdef INET6
1842 		case AF_INET6:
1843 			SC2IFP(sc)->if_flags |= IFF_UP;
1844 			error = carp_set_addr6(sc, satosin6(ifa->ifa_addr));
1845 			break;
1846 #endif /* INET6 */
1847 		default:
1848 			error = EAFNOSUPPORT;
1849 			break;
1850 		}
1851 		break;
1852 
1853 	case SIOCAIFADDR:
1854 		switch (ifa->ifa_addr->sa_family) {
1855 #ifdef INET
1856 		case AF_INET:
1857 			SC2IFP(sc)->if_flags |= IFF_UP;
1858 			bcopy(ifa->ifa_addr, ifa->ifa_dstaddr,
1859 			    sizeof(struct sockaddr));
1860 			error = carp_set_addr(sc, satosin(&ifra->ifra_addr));
1861 			break;
1862 #endif /* INET */
1863 #ifdef INET6
1864 		case AF_INET6:
1865 			SC2IFP(sc)->if_flags |= IFF_UP;
1866 			error = carp_set_addr6(sc, satosin6(&ifra->ifra_addr));
1867 			break;
1868 #endif /* INET6 */
1869 		default:
1870 			error = EAFNOSUPPORT;
1871 			break;
1872 		}
1873 		break;
1874 
1875 	case SIOCDIFADDR:
1876 		switch (ifa->ifa_addr->sa_family) {
1877 #ifdef INET
1878 		case AF_INET:
1879 			error = carp_del_addr(sc, satosin(&ifra->ifra_addr));
1880 			break;
1881 #endif /* INET */
1882 #ifdef INET6
1883 		case AF_INET6:
1884 			error = carp_del_addr6(sc, satosin6(&ifra->ifra_addr));
1885 			break;
1886 #endif /* INET6 */
1887 		default:
1888 			error = EAFNOSUPPORT;
1889 			break;
1890 		}
1891 		break;
1892 
1893 	case SIOCSIFFLAGS:
1894 		if (sc->sc_carpdev) {
1895 			locked = 1;
1896 			CARP_SCLOCK(sc);
1897 		}
1898 		if (sc->sc_state != INIT && !(ifr->ifr_flags & IFF_UP)) {
1899  			callout_stop(&sc->sc_ad_tmo);
1900  			callout_stop(&sc->sc_md_tmo);
1901  			callout_stop(&sc->sc_md6_tmo);
1902 			if (sc->sc_state == MASTER)
1903 				carp_send_ad_locked(sc);
1904 			carp_set_state(sc, INIT);
1905 			carp_setrun(sc, 0);
1906 		} else if (sc->sc_state == INIT && (ifr->ifr_flags & IFF_UP)) {
1907 			SC2IFP(sc)->if_flags |= IFF_UP;
1908 			carp_setrun(sc, 0);
1909 		}
1910 		break;
1911 
1912 	case SIOCSVH:
1913 		error = priv_check(curthread, PRIV_NETINET_CARP);
1914 		if (error)
1915 			break;
1916 		if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1917 			break;
1918 		error = 1;
1919 		if (sc->sc_carpdev) {
1920 			locked = 1;
1921 			CARP_SCLOCK(sc);
1922 		}
1923 		if (sc->sc_state != INIT && carpr.carpr_state != sc->sc_state) {
1924 			switch (carpr.carpr_state) {
1925 			case BACKUP:
1926 				callout_stop(&sc->sc_ad_tmo);
1927 				carp_set_state(sc, BACKUP);
1928 				carp_setrun(sc, 0);
1929 				carp_setroute(sc, RTM_DELETE);
1930 				break;
1931 			case MASTER:
1932 				carp_master_down_locked(sc);
1933 				break;
1934 			default:
1935 				break;
1936 			}
1937 		}
1938 		if (carpr.carpr_vhid > 0) {
1939 			if (carpr.carpr_vhid > 255) {
1940 				error = EINVAL;
1941 				break;
1942 			}
1943 			if (sc->sc_carpdev) {
1944 				struct carp_if *cif;
1945 				cif = (struct carp_if *)sc->sc_carpdev->if_carp;
1946 				TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list)
1947 					if (vr != sc &&
1948 					    vr->sc_vhid == carpr.carpr_vhid) {
1949 						error = EEXIST;
1950 						break;
1951 					}
1952 				if (error == EEXIST)
1953 					break;
1954 			}
1955 			sc->sc_vhid = carpr.carpr_vhid;
1956 			IF_LLADDR(sc->sc_ifp)[0] = 0;
1957 			IF_LLADDR(sc->sc_ifp)[1] = 0;
1958 			IF_LLADDR(sc->sc_ifp)[2] = 0x5e;
1959 			IF_LLADDR(sc->sc_ifp)[3] = 0;
1960 			IF_LLADDR(sc->sc_ifp)[4] = 1;
1961 			IF_LLADDR(sc->sc_ifp)[5] = sc->sc_vhid;
1962 			error--;
1963 		}
1964 		if (carpr.carpr_advbase > 0 || carpr.carpr_advskew > 0) {
1965 			if (carpr.carpr_advskew >= 255) {
1966 				error = EINVAL;
1967 				break;
1968 			}
1969 			if (carpr.carpr_advbase > 255) {
1970 				error = EINVAL;
1971 				break;
1972 			}
1973 			sc->sc_advbase = carpr.carpr_advbase;
1974 			sc->sc_advskew = carpr.carpr_advskew;
1975 			error--;
1976 		}
1977 		bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1978 		if (error > 0)
1979 			error = EINVAL;
1980 		else {
1981 			error = 0;
1982 			carp_setrun(sc, 0);
1983 		}
1984 		break;
1985 
1986 	case SIOCGVH:
1987 		/* XXX: lockless read */
1988 		bzero(&carpr, sizeof(carpr));
1989 		carpr.carpr_state = sc->sc_state;
1990 		carpr.carpr_vhid = sc->sc_vhid;
1991 		carpr.carpr_advbase = sc->sc_advbase;
1992 		carpr.carpr_advskew = sc->sc_advskew;
1993 		error = priv_check(curthread, PRIV_NETINET_CARP);
1994 		if (error == 0)
1995 			bcopy(sc->sc_key, carpr.carpr_key,
1996 			    sizeof(carpr.carpr_key));
1997 		error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
1998 		break;
1999 
2000 	default:
2001 		error = EINVAL;
2002 	}
2003 
2004 	if (locked)
2005 		CARP_SCUNLOCK(sc);
2006 
2007 	carp_hmac_prepare(sc);
2008 
2009 	return (error);
2010 }
2011 
2012 /*
2013  * XXX: this is looutput. We should eventually use it from there.
2014  */
2015 static int
2016 carp_looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
2017     struct rtentry *rt)
2018 {
2019 	u_int32_t af;
2020 
2021 	M_ASSERTPKTHDR(m); /* check if we have the packet header */
2022 
2023 	if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
2024 		m_freem(m);
2025 		return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
2026 			rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
2027 	}
2028 
2029 	ifp->if_opackets++;
2030 	ifp->if_obytes += m->m_pkthdr.len;
2031 
2032 	/* BPF writes need to be handled specially. */
2033 	if (dst->sa_family == AF_UNSPEC) {
2034 		bcopy(dst->sa_data, &af, sizeof(af));
2035 		dst->sa_family = af;
2036 	}
2037 
2038 #if 1	/* XXX */
2039 	switch (dst->sa_family) {
2040 	case AF_INET:
2041 	case AF_INET6:
2042 	case AF_IPX:
2043 	case AF_APPLETALK:
2044 		break;
2045 	default:
2046 		printf("carp_looutput: af=%d unexpected\n", dst->sa_family);
2047 		m_freem(m);
2048 		return (EAFNOSUPPORT);
2049 	}
2050 #endif
2051 	return(if_simloop(ifp, m, dst->sa_family, 0));
2052 }
2053 
2054 /*
2055  * Start output on carp interface. This function should never be called.
2056  */
2057 static void
2058 carp_start(struct ifnet *ifp)
2059 {
2060 #ifdef DEBUG
2061 	printf("%s: start called\n", ifp->if_xname);
2062 #endif
2063 }
2064 
2065 int
2066 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
2067     struct rtentry *rt)
2068 {
2069 	struct m_tag *mtag;
2070 	struct carp_softc *sc;
2071 	struct ifnet *carp_ifp;
2072 
2073 	if (!sa)
2074 		return (0);
2075 
2076 	switch (sa->sa_family) {
2077 #ifdef INET
2078 	case AF_INET:
2079 		break;
2080 #endif /* INET */
2081 #ifdef INET6
2082 	case AF_INET6:
2083 		break;
2084 #endif /* INET6 */
2085 	default:
2086 		return (0);
2087 	}
2088 
2089 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
2090 	if (mtag == NULL)
2091 		return (0);
2092 
2093 	bcopy(mtag + 1, &carp_ifp, sizeof(struct ifnet *));
2094 	sc = carp_ifp->if_softc;
2095 
2096 	/* Set the source MAC address to Virtual Router MAC Address */
2097 	switch (ifp->if_type) {
2098 	case IFT_ETHER:
2099 	case IFT_L2VLAN: {
2100 			struct ether_header *eh;
2101 
2102 			eh = mtod(m, struct ether_header *);
2103 			eh->ether_shost[0] = 0;
2104 			eh->ether_shost[1] = 0;
2105 			eh->ether_shost[2] = 0x5e;
2106 			eh->ether_shost[3] = 0;
2107 			eh->ether_shost[4] = 1;
2108 			eh->ether_shost[5] = sc->sc_vhid;
2109 		}
2110 		break;
2111 	case IFT_FDDI: {
2112 			struct fddi_header *fh;
2113 
2114 			fh = mtod(m, struct fddi_header *);
2115 			fh->fddi_shost[0] = 0;
2116 			fh->fddi_shost[1] = 0;
2117 			fh->fddi_shost[2] = 0x5e;
2118 			fh->fddi_shost[3] = 0;
2119 			fh->fddi_shost[4] = 1;
2120 			fh->fddi_shost[5] = sc->sc_vhid;
2121 		}
2122 		break;
2123 	case IFT_ISO88025: {
2124  			struct iso88025_header *th;
2125  			th = mtod(m, struct iso88025_header *);
2126 			th->iso88025_shost[0] = 3;
2127 			th->iso88025_shost[1] = 0;
2128 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
2129 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
2130 			th->iso88025_shost[4] = 0;
2131 			th->iso88025_shost[5] = 0;
2132 		}
2133 		break;
2134 	default:
2135 		printf("%s: carp is not supported for this interface type\n",
2136 		    ifp->if_xname);
2137 		return (EOPNOTSUPP);
2138 	}
2139 
2140 	return (0);
2141 }
2142 
2143 static void
2144 carp_set_state(struct carp_softc *sc, int state)
2145 {
2146 
2147 	if (sc->sc_carpdev)
2148 		CARP_SCLOCK_ASSERT(sc);
2149 
2150 	if (sc->sc_state == state)
2151 		return;
2152 
2153 	sc->sc_state = state;
2154 	switch (state) {
2155 	case BACKUP:
2156 		SC2IFP(sc)->if_link_state = LINK_STATE_DOWN;
2157 		break;
2158 	case MASTER:
2159 		SC2IFP(sc)->if_link_state = LINK_STATE_UP;
2160 		break;
2161 	default:
2162 		SC2IFP(sc)->if_link_state = LINK_STATE_UNKNOWN;
2163 		break;
2164 	}
2165 	rt_ifmsg(SC2IFP(sc));
2166 }
2167 
2168 void
2169 carp_carpdev_state(void *v)
2170 {
2171 	struct carp_if *cif = v;
2172 
2173 	CARP_LOCK(cif);
2174 	carp_carpdev_state_locked(cif);
2175 	CARP_UNLOCK(cif);
2176 }
2177 
2178 static void
2179 carp_carpdev_state_locked(struct carp_if *cif)
2180 {
2181 	struct carp_softc *sc;
2182 
2183 	TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list)
2184 		carp_sc_state_locked(sc);
2185 }
2186 
2187 static void
2188 carp_sc_state_locked(struct carp_softc *sc)
2189 {
2190 	CARP_SCLOCK_ASSERT(sc);
2191 
2192 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2193 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
2194 		sc->sc_flags_backup = SC2IFP(sc)->if_flags;
2195 		SC2IFP(sc)->if_flags &= ~IFF_UP;
2196 		SC2IFP(sc)->if_drv_flags &= ~IFF_DRV_RUNNING;
2197 		callout_stop(&sc->sc_ad_tmo);
2198 		callout_stop(&sc->sc_md_tmo);
2199 		callout_stop(&sc->sc_md6_tmo);
2200 		carp_set_state(sc, INIT);
2201 		carp_setrun(sc, 0);
2202 		if (!sc->sc_suppress) {
2203 			carp_suppress_preempt++;
2204 			if (carp_suppress_preempt == 1) {
2205 				CARP_SCUNLOCK(sc);
2206 				carp_send_ad_all();
2207 				CARP_SCLOCK(sc);
2208 			}
2209 		}
2210 		sc->sc_suppress = 1;
2211 	} else {
2212 		SC2IFP(sc)->if_flags |= sc->sc_flags_backup;
2213 		carp_set_state(sc, INIT);
2214 		carp_setrun(sc, 0);
2215 		if (sc->sc_suppress)
2216 			carp_suppress_preempt--;
2217 		sc->sc_suppress = 0;
2218 	}
2219 
2220 	return;
2221 }
2222 
2223 static int
2224 carp_modevent(module_t mod, int type, void *data)
2225 {
2226 	switch (type) {
2227 	case MOD_LOAD:
2228 		if_detach_event_tag = EVENTHANDLER_REGISTER(ifnet_departure_event,
2229 		    carp_ifdetach, NULL, EVENTHANDLER_PRI_ANY);
2230 		if (if_detach_event_tag == NULL)
2231 			return (ENOMEM);
2232 		mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2233 		LIST_INIT(&carpif_list);
2234 		if_clone_attach(&carp_cloner);
2235 		break;
2236 
2237 	case MOD_UNLOAD:
2238 		EVENTHANDLER_DEREGISTER(ifnet_departure_event, if_detach_event_tag);
2239 		if_clone_detach(&carp_cloner);
2240 		mtx_destroy(&carp_mtx);
2241 		break;
2242 
2243 	default:
2244 		return (EINVAL);
2245 	}
2246 
2247 	return (0);
2248 }
2249 
2250 static moduledata_t carp_mod = {
2251 	"carp",
2252 	carp_modevent,
2253 	0
2254 };
2255 
2256 DECLARE_MODULE(carp, carp_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
2257