xref: /freebsd/sys/netinet/ip_carp.c (revision 526e1dc1c0d052b9d2a6cd6da7a16eb09c971c54)
1 /*-
2  * Copyright (c) 2002 Michael Shalayeff.
3  * Copyright (c) 2003 Ryan McBride.
4  * Copyright (c) 2011 Gleb Smirnoff <glebius@FreeBSD.org>
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
25  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
26  * THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_bpf.h"
33 #include "opt_inet.h"
34 #include "opt_inet6.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/bus.h>
39 #include <sys/jail.h>
40 #include <sys/kernel.h>
41 #include <sys/limits.h>
42 #include <sys/malloc.h>
43 #include <sys/mbuf.h>
44 #include <sys/module.h>
45 #include <sys/priv.h>
46 #include <sys/proc.h>
47 #include <sys/protosw.h>
48 #include <sys/socket.h>
49 #include <sys/sockio.h>
50 #include <sys/sysctl.h>
51 #include <sys/syslog.h>
52 #include <sys/taskqueue.h>
53 
54 #include <net/ethernet.h>
55 #include <net/fddi.h>
56 #include <net/if.h>
57 #include <net/if_dl.h>
58 #include <net/if_llatbl.h>
59 #include <net/if_types.h>
60 #include <net/iso88025.h>
61 #include <net/route.h>
62 #include <net/vnet.h>
63 
64 #if defined(INET) || defined(INET6)
65 #include <netinet/in.h>
66 #include <netinet/in_var.h>
67 #include <netinet/ip_carp.h>
68 #include <netinet/ip.h>
69 #include <machine/in_cksum.h>
70 #endif
71 #ifdef INET
72 #include <netinet/ip_var.h>
73 #include <netinet/if_ether.h>
74 #endif
75 
76 #ifdef INET6
77 #include <netinet/icmp6.h>
78 #include <netinet/ip6.h>
79 #include <netinet6/ip6protosw.h>
80 #include <netinet6/in6_var.h>
81 #include <netinet6/ip6_var.h>
82 #include <netinet6/scope6_var.h>
83 #include <netinet6/nd6.h>
84 #endif
85 
86 #include <crypto/sha1.h>
87 
88 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
89 
90 struct carp_softc {
91 	struct ifnet		*sc_carpdev;	/* Pointer to parent ifnet. */
92 	struct ifaddr		**sc_ifas;	/* Our ifaddrs. */
93 	struct sockaddr_dl	sc_addr;	/* Our link level address. */
94 	struct callout		sc_ad_tmo;	/* Advertising timeout. */
95 #ifdef INET
96 	struct callout		sc_md_tmo;	/* Master down timeout. */
97 #endif
98 #ifdef INET6
99 	struct callout 		sc_md6_tmo;	/* XXX: Master down timeout. */
100 #endif
101 	struct mtx		sc_mtx;
102 
103 	int			sc_vhid;
104 	int			sc_advskew;
105 	int			sc_advbase;
106 
107 	int			sc_naddrs;
108 	int			sc_naddrs6;
109 	int			sc_ifasiz;
110 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
111 	int			sc_suppress;
112 	int			sc_sendad_errors;
113 #define	CARP_SENDAD_MAX_ERRORS	3
114 	int			sc_sendad_success;
115 #define	CARP_SENDAD_MIN_SUCCESS 3
116 
117 	int			sc_init_counter;
118 	uint64_t		sc_counter;
119 
120 	/* authentication */
121 #define	CARP_HMAC_PAD	64
122 	unsigned char sc_key[CARP_KEY_LEN];
123 	unsigned char sc_pad[CARP_HMAC_PAD];
124 	SHA1_CTX sc_sha1;
125 
126 	TAILQ_ENTRY(carp_softc)	sc_list;	/* On the carp_if list. */
127 	LIST_ENTRY(carp_softc)	sc_next;	/* On the global list. */
128 };
129 
130 struct carp_if {
131 #ifdef INET
132 	int	cif_naddrs;
133 #endif
134 #ifdef INET6
135 	int	cif_naddrs6;
136 #endif
137 	TAILQ_HEAD(, carp_softc) cif_vrs;
138 #ifdef INET
139 	struct ip_moptions 	 cif_imo;
140 #endif
141 #ifdef INET6
142 	struct ip6_moptions 	 cif_im6o;
143 #endif
144 	struct ifnet	*cif_ifp;
145 	struct mtx	cif_mtx;
146 };
147 
148 #define	CARP_INET	0
149 #define	CARP_INET6	1
150 static int proto_reg[] = {-1, -1};
151 
152 /*
153  * Brief design of carp(4).
154  *
155  * Any carp-capable ifnet may have a list of carp softcs hanging off
156  * its ifp->if_carp pointer. Each softc represents one unique virtual
157  * host id, or vhid. The softc has a back pointer to the ifnet. All
158  * softcs are joined in a global list, which has quite limited use.
159  *
160  * Any interface address that takes part in CARP negotiation has a
161  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
162  * AF_INET or AF_INET6 address.
163  *
164  * Although, one can get the softc's backpointer to ifnet and traverse
165  * through its ifp->if_addrhead queue to find all interface addresses
166  * involved in CARP, we keep a growable array of ifaddr pointers. This
167  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
168  * do calls into the network stack, thus avoiding LORs.
169  *
170  * Locking:
171  *
172  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
173  * callout-driven events and ioctl()s.
174  *
175  * To traverse the list of softcs on an ifnet we use CIF_LOCK(), to
176  * traverse the global list we use the mutex carp_mtx.
177  *
178  * Known issues with locking:
179  *
180  * - There is no protection for races between two ioctl() requests,
181  *   neither SIOCSVH, nor SIOCAIFADDR & SIOCAIFADDR_IN6. I think that all
182  *   interface ioctl()s should be serialized right in net/if.c.
183  * - Sending ad, we put the pointer to the softc in an mtag, and no reference
184  *   counting is done on the softc.
185  * - On module unload we may race (?) with packet processing thread
186  *   dereferencing our function pointers.
187  */
188 
189 static int carp_allow = 1;		/* Accept incoming CARP packets. */
190 static int carp_preempt = 0;		/* Preempt slower nodes. */
191 static int carp_log = 1;		/* Log level. */
192 static int carp_demotion = 0;		/* Global advskew demotion. */
193 static int carp_senderr_adj = CARP_MAXSKEW;	/* Send error demotion factor */
194 static int carp_ifdown_adj = CARP_MAXSKEW;	/* Iface down demotion factor */
195 
196 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
197 SYSCTL_INT(_net_inet_carp, OID_AUTO, allow, CTLFLAG_RW, &carp_allow, 0,
198     "Accept incoming CARP packets");
199 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_RW, &carp_preempt, 0,
200     "High-priority backup preemption mode");
201 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_RW, &carp_log, 0,
202     "CARP log level");
203 SYSCTL_INT(_net_inet_carp, OID_AUTO, demotion, CTLFLAG_RW, &carp_demotion, 0,
204     "Demotion factor (skew of advskew)");
205 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor, CTLFLAG_RW,
206     &carp_senderr_adj, 0, "Send error demotion factor adjustment");
207 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor, CTLFLAG_RW,
208     &carp_ifdown_adj, 0, "Interface down demotion factor adjustment");
209 
210 static struct carpstats carpstats;
211 SYSCTL_STRUCT(_net_inet_carp, OID_AUTO, stats, CTLFLAG_RW, &carpstats,
212     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
213 
214 #define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
215 	NULL, MTX_DEF)
216 #define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
217 #define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
218 #define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
219 #define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
220 #define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
221 	NULL, MTX_DEF)
222 #define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
223 #define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
224 #define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
225 #define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
226 #define	CIF_FREE(cif)	do {				\
227 		CIF_LOCK_ASSERT(cif);			\
228 		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
229 			carp_free_if(cif);		\
230 		else					\
231 			CIF_UNLOCK(cif);		\
232 } while (0)
233 
234 #define	CARP_LOG(...)	do {				\
235 	if (carp_log > 0)				\
236 		log(LOG_INFO, "carp: " __VA_ARGS__);	\
237 } while (0)
238 
239 #define	CARP_DEBUG(...)	do {				\
240 	if (carp_log > 1)				\
241 		log(LOG_DEBUG, __VA_ARGS__);		\
242 } while (0)
243 
244 #define	IFNET_FOREACH_IFA(ifp, ifa)					\
245 	IF_ADDR_LOCK_ASSERT(ifp);					\
246 	TAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)		\
247 		if ((ifa)->ifa_carp != NULL)
248 
249 #define	CARP_FOREACH_IFA(sc, ifa)					\
250 	CARP_LOCK_ASSERT(sc);						\
251 	for (int _i = 0;						\
252 		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
253 		((ifa) = sc->sc_ifas[_i]) != NULL;			\
254 		++_i)
255 
256 #define	IFNET_FOREACH_CARP(ifp, sc)					\
257 	CIF_LOCK_ASSERT(ifp->if_carp);					\
258 	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
259 
260 #define	DEMOTE_ADVSKEW(sc)					\
261     (((sc)->sc_advskew + carp_demotion > CARP_MAXSKEW) ?	\
262     CARP_MAXSKEW : ((sc)->sc_advskew + carp_demotion))
263 
264 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
265 static struct carp_softc
266 		*carp_alloc(struct ifnet *);
267 static void	carp_detach_locked(struct ifaddr *);
268 static void	carp_destroy(struct carp_softc *);
269 static struct carp_if
270 		*carp_alloc_if(struct ifnet *);
271 static void	carp_free_if(struct carp_if *);
272 static void	carp_set_state(struct carp_softc *, int);
273 static void	carp_sc_state(struct carp_softc *);
274 static void	carp_setrun(struct carp_softc *, sa_family_t);
275 static void	carp_master_down(void *);
276 static void	carp_master_down_locked(struct carp_softc *);
277 static void	carp_send_ad(void *);
278 static void	carp_send_ad_locked(struct carp_softc *);
279 static void	carp_addroute(struct carp_softc *);
280 static void	carp_ifa_addroute(struct ifaddr *);
281 static void	carp_delroute(struct carp_softc *);
282 static void	carp_ifa_delroute(struct ifaddr *);
283 static void	carp_send_ad_all(void *, int);
284 static void	carp_demote_adj(int, char *);
285 
286 static LIST_HEAD(, carp_softc) carp_list;
287 static struct mtx carp_mtx;
288 static struct task carp_sendall_task =
289     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
290 
291 static __inline uint16_t
292 carp_cksum(struct mbuf *m, int len)
293 {
294 	return (in_cksum(m, len));
295 }
296 
297 static void
298 carp_hmac_prepare(struct carp_softc *sc)
299 {
300 	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
301 	uint8_t vhid = sc->sc_vhid & 0xff;
302 	struct ifaddr *ifa;
303 	int i, found;
304 #ifdef INET
305 	struct in_addr last, cur, in;
306 #endif
307 #ifdef INET6
308 	struct in6_addr last6, cur6, in6;
309 #endif
310 
311 	CARP_LOCK_ASSERT(sc);
312 
313 	/* Compute ipad from key. */
314 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
315 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
316 	for (i = 0; i < sizeof(sc->sc_pad); i++)
317 		sc->sc_pad[i] ^= 0x36;
318 
319 	/* Precompute first part of inner hash. */
320 	SHA1Init(&sc->sc_sha1);
321 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
322 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
323 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
324 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
325 #ifdef INET
326 	cur.s_addr = 0;
327 	do {
328 		found = 0;
329 		last = cur;
330 		cur.s_addr = 0xffffffff;
331 		CARP_FOREACH_IFA(sc, ifa) {
332 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
333 			if (ifa->ifa_addr->sa_family == AF_INET &&
334 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
335 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
336 				cur.s_addr = in.s_addr;
337 				found++;
338 			}
339 		}
340 		if (found)
341 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
342 	} while (found);
343 #endif /* INET */
344 #ifdef INET6
345 	memset(&cur6, 0, sizeof(cur6));
346 	do {
347 		found = 0;
348 		last6 = cur6;
349 		memset(&cur6, 0xff, sizeof(cur6));
350 		CARP_FOREACH_IFA(sc, ifa) {
351 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
352 			if (IN6_IS_SCOPE_EMBED(&in6))
353 				in6.s6_addr16[1] = 0;
354 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
355 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
356 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
357 				cur6 = in6;
358 				found++;
359 			}
360 		}
361 		if (found)
362 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
363 	} while (found);
364 #endif /* INET6 */
365 
366 	/* convert ipad to opad */
367 	for (i = 0; i < sizeof(sc->sc_pad); i++)
368 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
369 }
370 
371 static void
372 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
373     unsigned char md[20])
374 {
375 	SHA1_CTX sha1ctx;
376 
377 	CARP_LOCK_ASSERT(sc);
378 
379 	/* fetch first half of inner hash */
380 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
381 
382 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
383 	SHA1Final(md, &sha1ctx);
384 
385 	/* outer hash */
386 	SHA1Init(&sha1ctx);
387 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
388 	SHA1Update(&sha1ctx, md, 20);
389 	SHA1Final(md, &sha1ctx);
390 }
391 
392 static int
393 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
394     unsigned char md[20])
395 {
396 	unsigned char md2[20];
397 
398 	CARP_LOCK_ASSERT(sc);
399 
400 	carp_hmac_generate(sc, counter, md2);
401 
402 	return (bcmp(md, md2, sizeof(md2)));
403 }
404 
405 /*
406  * process input packet.
407  * we have rearranged checks order compared to the rfc,
408  * but it seems more efficient this way or not possible otherwise.
409  */
410 #ifdef INET
411 void
412 carp_input(struct mbuf *m, int hlen)
413 {
414 	struct ip *ip = mtod(m, struct ip *);
415 	struct carp_header *ch;
416 	int iplen, len;
417 
418 	CARPSTATS_INC(carps_ipackets);
419 
420 	if (!carp_allow) {
421 		m_freem(m);
422 		return;
423 	}
424 
425 	/* verify that the IP TTL is 255.  */
426 	if (ip->ip_ttl != CARP_DFLTTL) {
427 		CARPSTATS_INC(carps_badttl);
428 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
429 		    ip->ip_ttl,
430 		    m->m_pkthdr.rcvif->if_xname);
431 		m_freem(m);
432 		return;
433 	}
434 
435 	iplen = ip->ip_hl << 2;
436 
437 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
438 		CARPSTATS_INC(carps_badlen);
439 		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
440 		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
441 		    m->m_pkthdr.rcvif->if_xname);
442 		m_freem(m);
443 		return;
444 	}
445 
446 	if (iplen + sizeof(*ch) < m->m_len) {
447 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
448 			CARPSTATS_INC(carps_hdrops);
449 			CARP_DEBUG("%s: pullup failed\n", __func__);
450 			return;
451 		}
452 		ip = mtod(m, struct ip *);
453 	}
454 	ch = (struct carp_header *)((char *)ip + iplen);
455 
456 	/*
457 	 * verify that the received packet length is
458 	 * equal to the CARP header
459 	 */
460 	len = iplen + sizeof(*ch);
461 	if (len > m->m_pkthdr.len) {
462 		CARPSTATS_INC(carps_badlen);
463 		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
464 		    m->m_pkthdr.len,
465 		    m->m_pkthdr.rcvif->if_xname);
466 		m_freem(m);
467 		return;
468 	}
469 
470 	if ((m = m_pullup(m, len)) == NULL) {
471 		CARPSTATS_INC(carps_hdrops);
472 		return;
473 	}
474 	ip = mtod(m, struct ip *);
475 	ch = (struct carp_header *)((char *)ip + iplen);
476 
477 	/* verify the CARP checksum */
478 	m->m_data += iplen;
479 	if (carp_cksum(m, len - iplen)) {
480 		CARPSTATS_INC(carps_badsum);
481 		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
482 		    m->m_pkthdr.rcvif->if_xname);
483 		m_freem(m);
484 		return;
485 	}
486 	m->m_data -= iplen;
487 
488 	carp_input_c(m, ch, AF_INET);
489 }
490 #endif
491 
492 #ifdef INET6
493 int
494 carp6_input(struct mbuf **mp, int *offp, int proto)
495 {
496 	struct mbuf *m = *mp;
497 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
498 	struct carp_header *ch;
499 	u_int len;
500 
501 	CARPSTATS_INC(carps_ipackets6);
502 
503 	if (!carp_allow) {
504 		m_freem(m);
505 		return (IPPROTO_DONE);
506 	}
507 
508 	/* check if received on a valid carp interface */
509 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
510 		CARPSTATS_INC(carps_badif);
511 		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
512 		    __func__, m->m_pkthdr.rcvif->if_xname);
513 		m_freem(m);
514 		return (IPPROTO_DONE);
515 	}
516 
517 	/* verify that the IP TTL is 255 */
518 	if (ip6->ip6_hlim != CARP_DFLTTL) {
519 		CARPSTATS_INC(carps_badttl);
520 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
521 		    ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
522 		m_freem(m);
523 		return (IPPROTO_DONE);
524 	}
525 
526 	/* verify that we have a complete carp packet */
527 	len = m->m_len;
528 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
529 	if (ch == NULL) {
530 		CARPSTATS_INC(carps_badlen);
531 		CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
532 		return (IPPROTO_DONE);
533 	}
534 
535 
536 	/* verify the CARP checksum */
537 	m->m_data += *offp;
538 	if (carp_cksum(m, sizeof(*ch))) {
539 		CARPSTATS_INC(carps_badsum);
540 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
541 		    m->m_pkthdr.rcvif->if_xname);
542 		m_freem(m);
543 		return (IPPROTO_DONE);
544 	}
545 	m->m_data -= *offp;
546 
547 	carp_input_c(m, ch, AF_INET6);
548 	return (IPPROTO_DONE);
549 }
550 #endif /* INET6 */
551 
552 static void
553 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
554 {
555 	struct ifnet *ifp = m->m_pkthdr.rcvif;
556 	struct ifaddr *ifa;
557 	struct carp_softc *sc;
558 	uint64_t tmp_counter;
559 	struct timeval sc_tv, ch_tv;
560 
561 	/* verify that the VHID is valid on the receiving interface */
562 	IF_ADDR_RLOCK(ifp);
563 	IFNET_FOREACH_IFA(ifp, ifa)
564 		if (ifa->ifa_addr->sa_family == af &&
565 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid) {
566 			ifa_ref(ifa);
567 			break;
568 		}
569 	IF_ADDR_RUNLOCK(ifp);
570 
571 	if (ifa == NULL) {
572 		CARPSTATS_INC(carps_badvhid);
573 		m_freem(m);
574 		return;
575 	}
576 
577 	/* verify the CARP version. */
578 	if (ch->carp_version != CARP_VERSION) {
579 		CARPSTATS_INC(carps_badver);
580 		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
581 		    ch->carp_version);
582 		ifa_free(ifa);
583 		m_freem(m);
584 		return;
585 	}
586 
587 	sc = ifa->ifa_carp;
588 	CARP_LOCK(sc);
589 	ifa_free(ifa);
590 
591 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
592 		CARPSTATS_INC(carps_badauth);
593 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
594 		    sc->sc_vhid, ifp->if_xname);
595 		goto out;
596 	}
597 
598 	tmp_counter = ntohl(ch->carp_counter[0]);
599 	tmp_counter = tmp_counter<<32;
600 	tmp_counter += ntohl(ch->carp_counter[1]);
601 
602 	/* XXX Replay protection goes here */
603 
604 	sc->sc_init_counter = 0;
605 	sc->sc_counter = tmp_counter;
606 
607 	sc_tv.tv_sec = sc->sc_advbase;
608 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
609 	ch_tv.tv_sec = ch->carp_advbase;
610 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
611 
612 	switch (sc->sc_state) {
613 	case INIT:
614 		break;
615 	case MASTER:
616 		/*
617 		 * If we receive an advertisement from a master who's going to
618 		 * be more frequent than us, go into BACKUP state.
619 		 */
620 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
621 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
622 			callout_stop(&sc->sc_ad_tmo);
623 			CARP_LOG("VHID %u@%s: MASTER -> BACKUP "
624 			    "(more frequent advertisement received)\n",
625 			    sc->sc_vhid,
626 			    sc->sc_carpdev->if_xname);
627 			carp_set_state(sc, BACKUP);
628 			carp_setrun(sc, 0);
629 			carp_delroute(sc);
630 		}
631 		break;
632 	case BACKUP:
633 		/*
634 		 * If we're pre-empting masters who advertise slower than us,
635 		 * and this one claims to be slower, treat him as down.
636 		 */
637 		if (carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
638 			CARP_LOG("VHID %u@%s: BACKUP -> MASTER "
639 			    "(preempting a slower master)\n",
640 			    sc->sc_vhid,
641 			    sc->sc_carpdev->if_xname);
642 			carp_master_down_locked(sc);
643 			break;
644 		}
645 
646 		/*
647 		 *  If the master is going to advertise at such a low frequency
648 		 *  that he's guaranteed to time out, we'd might as well just
649 		 *  treat him as timed out now.
650 		 */
651 		sc_tv.tv_sec = sc->sc_advbase * 3;
652 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
653 			CARP_LOG("VHID %u@%s: BACKUP -> MASTER "
654 			    "(master timed out)\n",
655 			    sc->sc_vhid,
656 			    sc->sc_carpdev->if_xname);
657 			carp_master_down_locked(sc);
658 			break;
659 		}
660 
661 		/*
662 		 * Otherwise, we reset the counter and wait for the next
663 		 * advertisement.
664 		 */
665 		carp_setrun(sc, af);
666 		break;
667 	}
668 
669 out:
670 	CARP_UNLOCK(sc);
671 	m_freem(m);
672 }
673 
674 static int
675 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
676 {
677 	struct m_tag *mtag;
678 
679 	if (sc->sc_init_counter) {
680 		/* this could also be seconds since unix epoch */
681 		sc->sc_counter = arc4random();
682 		sc->sc_counter = sc->sc_counter << 32;
683 		sc->sc_counter += arc4random();
684 	} else
685 		sc->sc_counter++;
686 
687 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
688 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
689 
690 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
691 
692 	/* Tag packet for carp_output */
693 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
694 	    M_NOWAIT)) == NULL) {
695 		m_freem(m);
696 		CARPSTATS_INC(carps_onomem);
697 		return (ENOMEM);
698 	}
699 	bcopy(&sc, mtag + 1, sizeof(sc));
700 	m_tag_prepend(m, mtag);
701 
702 	return (0);
703 }
704 
705 /*
706  * To avoid LORs and possible recursions this function shouldn't
707  * be called directly, but scheduled via taskqueue.
708  */
709 static void
710 carp_send_ad_all(void *ctx __unused, int pending __unused)
711 {
712 	struct carp_softc *sc;
713 
714 	mtx_lock(&carp_mtx);
715 	LIST_FOREACH(sc, &carp_list, sc_next)
716 		if (sc->sc_state == MASTER) {
717 			CARP_LOCK(sc);
718 			CURVNET_SET(sc->sc_carpdev->if_vnet);
719 			carp_send_ad_locked(sc);
720 			CURVNET_RESTORE();
721 			CARP_UNLOCK(sc);
722 		}
723 	mtx_unlock(&carp_mtx);
724 }
725 
726 /* Send a periodic advertisement, executed in callout context. */
727 static void
728 carp_send_ad(void *v)
729 {
730 	struct carp_softc *sc = v;
731 
732 	CARP_LOCK_ASSERT(sc);
733 	CURVNET_SET(sc->sc_carpdev->if_vnet);
734 	carp_send_ad_locked(sc);
735 	CURVNET_RESTORE();
736 	CARP_UNLOCK(sc);
737 }
738 
739 static void
740 carp_send_ad_locked(struct carp_softc *sc)
741 {
742 	struct carp_header ch;
743 	struct timeval tv;
744 	struct sockaddr sa;
745 	struct ifaddr *ifa;
746 	struct carp_header *ch_ptr;
747 	struct mbuf *m;
748 	int len, advskew;
749 
750 	CARP_LOCK_ASSERT(sc);
751 
752 	advskew = DEMOTE_ADVSKEW(sc);
753 	tv.tv_sec = sc->sc_advbase;
754 	tv.tv_usec = advskew * 1000000 / 256;
755 
756 	ch.carp_version = CARP_VERSION;
757 	ch.carp_type = CARP_ADVERTISEMENT;
758 	ch.carp_vhid = sc->sc_vhid;
759 	ch.carp_advbase = sc->sc_advbase;
760 	ch.carp_advskew = advskew;
761 	ch.carp_authlen = 7;	/* XXX DEFINE */
762 	ch.carp_pad1 = 0;	/* must be zero */
763 	ch.carp_cksum = 0;
764 
765 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
766 
767 #ifdef INET
768 	if (sc->sc_naddrs) {
769 		struct ip *ip;
770 
771 		MGETHDR(m, M_NOWAIT, MT_HEADER);
772 		if (m == NULL) {
773 			CARPSTATS_INC(carps_onomem);
774 			goto resched;
775 		}
776 		len = sizeof(*ip) + sizeof(ch);
777 		m->m_pkthdr.len = len;
778 		m->m_pkthdr.rcvif = NULL;
779 		m->m_len = len;
780 		MH_ALIGN(m, m->m_len);
781 		m->m_flags |= M_MCAST;
782 		ip = mtod(m, struct ip *);
783 		ip->ip_v = IPVERSION;
784 		ip->ip_hl = sizeof(*ip) >> 2;
785 		ip->ip_tos = IPTOS_LOWDELAY;
786 		ip->ip_len = htons(len);
787 		ip->ip_id = ip_newid();
788 		ip->ip_off = htons(IP_DF);
789 		ip->ip_ttl = CARP_DFLTTL;
790 		ip->ip_p = IPPROTO_CARP;
791 		ip->ip_sum = 0;
792 
793 		bzero(&sa, sizeof(sa));
794 		sa.sa_family = AF_INET;
795 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
796 		if (ifa != NULL) {
797 			ip->ip_src.s_addr =
798 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
799 			ifa_free(ifa);
800 		} else
801 			ip->ip_src.s_addr = 0;
802 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
803 
804 		ch_ptr = (struct carp_header *)(&ip[1]);
805 		bcopy(&ch, ch_ptr, sizeof(ch));
806 		if (carp_prepare_ad(m, sc, ch_ptr))
807 			goto resched;
808 
809 		m->m_data += sizeof(*ip);
810 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip));
811 		m->m_data -= sizeof(*ip);
812 
813 		CARPSTATS_INC(carps_opackets);
814 
815 		if (ip_output(m, NULL, NULL, IP_RAWOUTPUT,
816 		    &sc->sc_carpdev->if_carp->cif_imo, NULL)) {
817 			if (sc->sc_sendad_errors < INT_MAX)
818 				sc->sc_sendad_errors++;
819 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS)
820 				carp_demote_adj(carp_senderr_adj, "send error");
821 			sc->sc_sendad_success = 0;
822 		} else {
823 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
824 				if (++sc->sc_sendad_success >=
825 				    CARP_SENDAD_MIN_SUCCESS) {
826 					carp_demote_adj(-carp_senderr_adj,
827 					    "send ok");
828 					sc->sc_sendad_errors = 0;
829 				}
830 			} else
831 				sc->sc_sendad_errors = 0;
832 		}
833 	}
834 #endif /* INET */
835 #ifdef INET6
836 	if (sc->sc_naddrs6) {
837 		struct ip6_hdr *ip6;
838 
839 		MGETHDR(m, M_NOWAIT, MT_HEADER);
840 		if (m == NULL) {
841 			CARPSTATS_INC(carps_onomem);
842 			goto resched;
843 		}
844 		len = sizeof(*ip6) + sizeof(ch);
845 		m->m_pkthdr.len = len;
846 		m->m_pkthdr.rcvif = NULL;
847 		m->m_len = len;
848 		MH_ALIGN(m, m->m_len);
849 		m->m_flags |= M_MCAST;
850 		ip6 = mtod(m, struct ip6_hdr *);
851 		bzero(ip6, sizeof(*ip6));
852 		ip6->ip6_vfc |= IPV6_VERSION;
853 		ip6->ip6_hlim = CARP_DFLTTL;
854 		ip6->ip6_nxt = IPPROTO_CARP;
855 		bzero(&sa, sizeof(sa));
856 
857 		/* set the source address */
858 		sa.sa_family = AF_INET6;
859 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
860 		if (ifa != NULL) {
861 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
862 			    sizeof(struct in6_addr));
863 			ifa_free(ifa);
864 		} else
865 			/* This should never happen with IPv6. */
866 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
867 
868 		/* Set the multicast destination. */
869 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
870 		ip6->ip6_dst.s6_addr8[15] = 0x12;
871 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
872 			m_freem(m);
873 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
874 			goto resched;
875 		}
876 
877 		ch_ptr = (struct carp_header *)(&ip6[1]);
878 		bcopy(&ch, ch_ptr, sizeof(ch));
879 		if (carp_prepare_ad(m, sc, ch_ptr))
880 			goto resched;
881 
882 		m->m_data += sizeof(*ip6);
883 		ch_ptr->carp_cksum = carp_cksum(m, len - sizeof(*ip6));
884 		m->m_data -= sizeof(*ip6);
885 
886 		CARPSTATS_INC(carps_opackets6);
887 
888 		if (ip6_output(m, NULL, NULL, 0,
889 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL)) {
890 			if (sc->sc_sendad_errors < INT_MAX)
891 				sc->sc_sendad_errors++;
892 			if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS)
893 				carp_demote_adj(carp_senderr_adj,
894 				    "send6 error");
895 			sc->sc_sendad_success = 0;
896 		} else {
897 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
898 				if (++sc->sc_sendad_success >=
899 				    CARP_SENDAD_MIN_SUCCESS) {
900 					carp_demote_adj(-carp_senderr_adj,
901 					    "send6 ok");
902 					sc->sc_sendad_errors = 0;
903 				}
904 			} else
905 				sc->sc_sendad_errors = 0;
906 		}
907 	}
908 #endif /* INET6 */
909 
910 resched:
911 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
912 }
913 
914 static void
915 carp_addroute(struct carp_softc *sc)
916 {
917 	struct ifaddr *ifa;
918 
919 	CARP_FOREACH_IFA(sc, ifa)
920 		carp_ifa_addroute(ifa);
921 }
922 
923 static void
924 carp_ifa_addroute(struct ifaddr *ifa)
925 {
926 
927 	switch (ifa->ifa_addr->sa_family) {
928 #ifdef INET
929 	case AF_INET:
930 		in_addprefix(ifatoia(ifa), RTF_UP);
931 		ifa_add_loopback_route(ifa,
932 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
933 		break;
934 #endif
935 #ifdef INET6
936 	case AF_INET6:
937 		ifa_add_loopback_route(ifa,
938 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
939 		in6_ifaddloop(ifa);
940 		break;
941 #endif
942 	}
943 }
944 
945 static void
946 carp_delroute(struct carp_softc *sc)
947 {
948 	struct ifaddr *ifa;
949 
950 	CARP_FOREACH_IFA(sc, ifa)
951 		carp_ifa_delroute(ifa);
952 }
953 
954 static void
955 carp_ifa_delroute(struct ifaddr *ifa)
956 {
957 
958 	switch (ifa->ifa_addr->sa_family) {
959 #ifdef INET
960 	case AF_INET:
961 		ifa_del_loopback_route(ifa,
962 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
963 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
964 		break;
965 #endif
966 #ifdef INET6
967 	case AF_INET6:
968 		ifa_del_loopback_route(ifa,
969 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
970 		in6_ifremloop(ifa);
971 		break;
972 #endif
973 	}
974 }
975 
976 #ifdef INET
977 /*
978  * Broadcast a gratuitous ARP request containing
979  * the virtual router MAC address for each IP address
980  * associated with the virtual router.
981  */
982 static void
983 carp_send_arp(struct carp_softc *sc)
984 {
985 	struct ifaddr *ifa;
986 
987 	CARP_FOREACH_IFA(sc, ifa)
988 		if (ifa->ifa_addr->sa_family == AF_INET)
989 			arp_ifinit2(sc->sc_carpdev, ifa, LLADDR(&sc->sc_addr));
990 }
991 
992 int
993 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
994 {
995 	struct carp_softc *sc = ifa->ifa_carp;
996 
997 	if (sc->sc_state == MASTER) {
998 		*enaddr = LLADDR(&sc->sc_addr);
999 		return (1);
1000 	}
1001 
1002 	return (0);
1003 }
1004 #endif
1005 
1006 #ifdef INET6
1007 static void
1008 carp_send_na(struct carp_softc *sc)
1009 {
1010 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1011 	struct ifaddr *ifa;
1012 	struct in6_addr *in6;
1013 
1014 	CARP_FOREACH_IFA(sc, ifa) {
1015 		if (ifa->ifa_addr->sa_family != AF_INET6)
1016 			continue;
1017 
1018 		in6 = IFA_IN6(ifa);
1019 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1020 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1021 		DELAY(1000);	/* XXX */
1022 	}
1023 }
1024 
1025 /*
1026  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1027  * matches and is not a carp address.  Returns NULL otherwise.
1028  */
1029 struct ifaddr *
1030 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1031 {
1032 	struct ifaddr *ifa;
1033 
1034 	ifa = NULL;
1035 	IF_ADDR_RLOCK(ifp);
1036 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1037 		if (ifa->ifa_addr->sa_family != AF_INET6)
1038 			continue;
1039 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1040 			continue;
1041 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1042 			ifa = NULL;
1043 		else
1044 			ifa_ref(ifa);
1045 		break;
1046 	}
1047 	IF_ADDR_RUNLOCK(ifp);
1048 
1049 	return (ifa);
1050 }
1051 
1052 caddr_t
1053 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1054 {
1055 	struct ifaddr *ifa;
1056 
1057 	IF_ADDR_RLOCK(ifp);
1058 	IFNET_FOREACH_IFA(ifp, ifa)
1059 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1060 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1061 			struct carp_softc *sc = ifa->ifa_carp;
1062 			struct m_tag *mtag;
1063 
1064 			IF_ADDR_RUNLOCK(ifp);
1065 
1066 			mtag = m_tag_get(PACKET_TAG_CARP,
1067 			    sizeof(struct carp_softc *), M_NOWAIT);
1068 			if (mtag == NULL)
1069 				/* Better a bit than nothing. */
1070 				return (LLADDR(&sc->sc_addr));
1071 
1072 			bcopy(&sc, mtag + 1, sizeof(sc));
1073 			m_tag_prepend(m, mtag);
1074 
1075 			return (LLADDR(&sc->sc_addr));
1076 		}
1077 	IF_ADDR_RUNLOCK(ifp);
1078 
1079 	return (NULL);
1080 }
1081 #endif /* INET6 */
1082 
1083 int
1084 carp_forus(struct ifnet *ifp, u_char *dhost)
1085 {
1086 	struct carp_softc *sc;
1087 	uint8_t *ena = dhost;
1088 
1089 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1090 		return (0);
1091 
1092 	CIF_LOCK(ifp->if_carp);
1093 	IFNET_FOREACH_CARP(ifp, sc) {
1094 		CARP_LOCK(sc);
1095 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1096 		    ETHER_ADDR_LEN)) {
1097 			CARP_UNLOCK(sc);
1098 			CIF_UNLOCK(ifp->if_carp);
1099 			return (1);
1100 		}
1101 		CARP_UNLOCK(sc);
1102 	}
1103 	CIF_UNLOCK(ifp->if_carp);
1104 
1105 	return (0);
1106 }
1107 
1108 /* Master down timeout event, executed in callout context. */
1109 static void
1110 carp_master_down(void *v)
1111 {
1112 	struct carp_softc *sc = v;
1113 
1114 	CARP_LOCK_ASSERT(sc);
1115 
1116 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1117 	if (sc->sc_state == BACKUP) {
1118 		CARP_LOG("VHID %u@%s: BACKUP -> MASTER (master down)\n",
1119 		    sc->sc_vhid,
1120 		    sc->sc_carpdev->if_xname);
1121 		carp_master_down_locked(sc);
1122 	}
1123 	CURVNET_RESTORE();
1124 
1125 	CARP_UNLOCK(sc);
1126 }
1127 
1128 static void
1129 carp_master_down_locked(struct carp_softc *sc)
1130 {
1131 
1132 	CARP_LOCK_ASSERT(sc);
1133 
1134 	switch (sc->sc_state) {
1135 	case BACKUP:
1136 		carp_set_state(sc, MASTER);
1137 		carp_send_ad_locked(sc);
1138 #ifdef INET
1139 		carp_send_arp(sc);
1140 #endif
1141 #ifdef INET6
1142 		carp_send_na(sc);
1143 #endif
1144 		carp_setrun(sc, 0);
1145 		carp_addroute(sc);
1146 		break;
1147 	case INIT:
1148 	case MASTER:
1149 #ifdef INVARIANTS
1150 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1151 		    sc->sc_vhid,
1152 		    sc->sc_carpdev->if_xname,
1153 		    sc->sc_state ? "MASTER" : "INIT");
1154 #endif
1155 		break;
1156 	}
1157 }
1158 
1159 /*
1160  * When in backup state, af indicates whether to reset the master down timer
1161  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1162  */
1163 static void
1164 carp_setrun(struct carp_softc *sc, sa_family_t af)
1165 {
1166 	struct timeval tv;
1167 
1168 	CARP_LOCK_ASSERT(sc);
1169 
1170 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1171 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1172 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0))
1173 		return;
1174 
1175 	switch (sc->sc_state) {
1176 	case INIT:
1177 		CARP_LOG("VHID %u@%s: INIT -> BACKUP\n",
1178 		    sc->sc_vhid,
1179 		    sc->sc_carpdev->if_xname);
1180 		carp_set_state(sc, BACKUP);
1181 		carp_setrun(sc, 0);
1182 		break;
1183 	case BACKUP:
1184 		callout_stop(&sc->sc_ad_tmo);
1185 		tv.tv_sec = 3 * sc->sc_advbase;
1186 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1187 		switch (af) {
1188 #ifdef INET
1189 		case AF_INET:
1190 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1191 			    carp_master_down, sc);
1192 			break;
1193 #endif
1194 #ifdef INET6
1195 		case AF_INET6:
1196 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1197 			    carp_master_down, sc);
1198 			break;
1199 #endif
1200 		default:
1201 #ifdef INET
1202 			if (sc->sc_naddrs)
1203 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1204 				    carp_master_down, sc);
1205 #endif
1206 #ifdef INET6
1207 			if (sc->sc_naddrs6)
1208 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1209 				    carp_master_down, sc);
1210 #endif
1211 			break;
1212 		}
1213 		break;
1214 	case MASTER:
1215 		tv.tv_sec = sc->sc_advbase;
1216 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1217 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1218 		    carp_send_ad, sc);
1219 		break;
1220 	}
1221 }
1222 
1223 /*
1224  * Setup multicast structures.
1225  */
1226 static int
1227 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1228 {
1229 	struct ifnet *ifp = cif->cif_ifp;
1230 	int error = 0;
1231 
1232 	CIF_LOCK_ASSERT(cif);
1233 
1234 	switch (sa) {
1235 #ifdef INET
1236 	case AF_INET:
1237 	    {
1238 		struct ip_moptions *imo = &cif->cif_imo;
1239 		struct in_addr addr;
1240 
1241 		if (imo->imo_membership)
1242 			return (0);
1243 
1244 		imo->imo_membership = (struct in_multi **)malloc(
1245 		    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
1246 		    M_NOWAIT);
1247 		if (imo->imo_membership == NULL)
1248 			return (ENOMEM);
1249 		imo->imo_mfilters = NULL;
1250 		imo->imo_max_memberships = IP_MIN_MEMBERSHIPS;
1251 		imo->imo_multicast_vif = -1;
1252 
1253 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1254 		if ((error = in_joingroup(ifp, &addr, NULL,
1255 		    &imo->imo_membership[0])) != 0) {
1256 			free(imo->imo_membership, M_CARP);
1257 			break;
1258 		}
1259 		imo->imo_num_memberships++;
1260 		imo->imo_multicast_ifp = ifp;
1261 		imo->imo_multicast_ttl = CARP_DFLTTL;
1262 		imo->imo_multicast_loop = 0;
1263 		break;
1264 	   }
1265 #endif
1266 #ifdef INET6
1267 	case AF_INET6:
1268 	    {
1269 		struct ip6_moptions *im6o = &cif->cif_im6o;
1270 		struct in6_addr in6;
1271 		struct in6_multi *in6m;
1272 
1273 		if (im6o->im6o_membership)
1274 			return (0);
1275 
1276 		im6o->im6o_membership = (struct in6_multi **)malloc(
1277 		    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
1278 		    M_ZERO | M_NOWAIT);
1279 		if (im6o->im6o_membership == NULL)
1280 			return (ENOMEM);
1281 		im6o->im6o_mfilters = NULL;
1282 		im6o->im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
1283 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1284 		im6o->im6o_multicast_ifp = ifp;
1285 
1286 		/* Join IPv6 CARP multicast group. */
1287 		bzero(&in6, sizeof(in6));
1288 		in6.s6_addr16[0] = htons(0xff02);
1289 		in6.s6_addr8[15] = 0x12;
1290 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1291 			free(im6o->im6o_membership, M_CARP);
1292 			break;
1293 		}
1294 		in6m = NULL;
1295 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1296 			free(im6o->im6o_membership, M_CARP);
1297 			break;
1298 		}
1299 		im6o->im6o_membership[0] = in6m;
1300 		im6o->im6o_num_memberships++;
1301 
1302 		/* Join solicited multicast address. */
1303 		bzero(&in6, sizeof(in6));
1304 		in6.s6_addr16[0] = htons(0xff02);
1305 		in6.s6_addr32[1] = 0;
1306 		in6.s6_addr32[2] = htonl(1);
1307 		in6.s6_addr32[3] = 0;
1308 		in6.s6_addr8[12] = 0xff;
1309 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1310 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1311 			free(im6o->im6o_membership, M_CARP);
1312 			break;
1313 		}
1314 		in6m = NULL;
1315 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1316 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1317 			free(im6o->im6o_membership, M_CARP);
1318 			break;
1319 		}
1320 		im6o->im6o_membership[1] = in6m;
1321 		im6o->im6o_num_memberships++;
1322 		break;
1323 	    }
1324 #endif
1325 	}
1326 
1327 	return (error);
1328 }
1329 
1330 /*
1331  * Free multicast structures.
1332  */
1333 static void
1334 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1335 {
1336 
1337 	CIF_LOCK_ASSERT(cif);
1338 	switch (sa) {
1339 #ifdef INET
1340 	case AF_INET:
1341 		if (cif->cif_naddrs == 0) {
1342 			struct ip_moptions *imo = &cif->cif_imo;
1343 
1344 			in_leavegroup(imo->imo_membership[0], NULL);
1345 			KASSERT(imo->imo_mfilters == NULL,
1346 			    ("%s: imo_mfilters != NULL", __func__));
1347 			free(imo->imo_membership, M_CARP);
1348 			imo->imo_membership = NULL;
1349 
1350 		}
1351 		break;
1352 #endif
1353 #ifdef INET6
1354 	case AF_INET6:
1355 		if (cif->cif_naddrs6 == 0) {
1356 			struct ip6_moptions *im6o = &cif->cif_im6o;
1357 
1358 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1359 			in6_mc_leave(im6o->im6o_membership[1], NULL);
1360 			KASSERT(im6o->im6o_mfilters == NULL,
1361 			    ("%s: im6o_mfilters != NULL", __func__));
1362 			free(im6o->im6o_membership, M_CARP);
1363 			im6o->im6o_membership = NULL;
1364 		}
1365 		break;
1366 #endif
1367 	}
1368 }
1369 
1370 int
1371 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa)
1372 {
1373 	struct m_tag *mtag;
1374 	struct carp_softc *sc;
1375 
1376 	if (!sa)
1377 		return (0);
1378 
1379 	switch (sa->sa_family) {
1380 #ifdef INET
1381 	case AF_INET:
1382 		break;
1383 #endif
1384 #ifdef INET6
1385 	case AF_INET6:
1386 		break;
1387 #endif
1388 	default:
1389 		return (0);
1390 	}
1391 
1392 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1393 	if (mtag == NULL)
1394 		return (0);
1395 
1396 	bcopy(mtag + 1, &sc, sizeof(sc));
1397 
1398 	/* Set the source MAC address to the Virtual Router MAC Address. */
1399 	switch (ifp->if_type) {
1400 	case IFT_ETHER:
1401 	case IFT_BRIDGE:
1402 	case IFT_L2VLAN: {
1403 			struct ether_header *eh;
1404 
1405 			eh = mtod(m, struct ether_header *);
1406 			eh->ether_shost[0] = 0;
1407 			eh->ether_shost[1] = 0;
1408 			eh->ether_shost[2] = 0x5e;
1409 			eh->ether_shost[3] = 0;
1410 			eh->ether_shost[4] = 1;
1411 			eh->ether_shost[5] = sc->sc_vhid;
1412 		}
1413 		break;
1414 	case IFT_FDDI: {
1415 			struct fddi_header *fh;
1416 
1417 			fh = mtod(m, struct fddi_header *);
1418 			fh->fddi_shost[0] = 0;
1419 			fh->fddi_shost[1] = 0;
1420 			fh->fddi_shost[2] = 0x5e;
1421 			fh->fddi_shost[3] = 0;
1422 			fh->fddi_shost[4] = 1;
1423 			fh->fddi_shost[5] = sc->sc_vhid;
1424 		}
1425 		break;
1426 	case IFT_ISO88025: {
1427  			struct iso88025_header *th;
1428  			th = mtod(m, struct iso88025_header *);
1429 			th->iso88025_shost[0] = 3;
1430 			th->iso88025_shost[1] = 0;
1431 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
1432 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
1433 			th->iso88025_shost[4] = 0;
1434 			th->iso88025_shost[5] = 0;
1435 		}
1436 		break;
1437 	default:
1438 		printf("%s: carp is not supported for the %d interface type\n",
1439 		    ifp->if_xname, ifp->if_type);
1440 		return (EOPNOTSUPP);
1441 	}
1442 
1443 	return (0);
1444 }
1445 
1446 static struct carp_softc*
1447 carp_alloc(struct ifnet *ifp)
1448 {
1449 	struct carp_softc *sc;
1450 	struct carp_if *cif;
1451 
1452 	if ((cif = ifp->if_carp) == NULL) {
1453 		cif = carp_alloc_if(ifp);
1454 		if (cif == NULL)
1455 			return (NULL);
1456 	}
1457 
1458 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1459 
1460 	sc->sc_advbase = CARP_DFLTINTV;
1461 	sc->sc_vhid = -1;	/* required setting */
1462 	sc->sc_init_counter = 1;
1463 	sc->sc_state = INIT;
1464 
1465 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1466 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1467 	sc->sc_carpdev = ifp;
1468 
1469 	CARP_LOCK_INIT(sc);
1470 #ifdef INET
1471 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1472 #endif
1473 #ifdef INET6
1474 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1475 #endif
1476 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1477 
1478 	CIF_LOCK(cif);
1479 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1480 	CIF_UNLOCK(cif);
1481 
1482 	mtx_lock(&carp_mtx);
1483 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1484 	mtx_unlock(&carp_mtx);
1485 
1486 	return (sc);
1487 }
1488 
1489 static int
1490 carp_grow_ifas(struct carp_softc *sc)
1491 {
1492 	struct ifaddr **new;
1493 
1494 	CARP_LOCK_ASSERT(sc);
1495 
1496 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_NOWAIT|M_ZERO);
1497 	if (new == NULL)
1498 		return (ENOMEM);
1499 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1500 	free(sc->sc_ifas, M_CARP);
1501 	sc->sc_ifas = new;
1502 	sc->sc_ifasiz *= 2;
1503 
1504 	return (0);
1505 }
1506 
1507 static void
1508 carp_destroy(struct carp_softc *sc)
1509 {
1510 	struct ifnet *ifp = sc->sc_carpdev;
1511 	struct carp_if *cif = ifp->if_carp;
1512 
1513 	CIF_LOCK_ASSERT(cif);
1514 
1515 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1516 
1517 	mtx_lock(&carp_mtx);
1518 	LIST_REMOVE(sc, sc_next);
1519 	mtx_unlock(&carp_mtx);
1520 
1521 	CARP_LOCK(sc);
1522 	if (sc->sc_suppress)
1523 		carp_demote_adj(-carp_ifdown_adj, "vhid removed");
1524 	callout_drain(&sc->sc_ad_tmo);
1525 #ifdef INET
1526 	callout_drain(&sc->sc_md_tmo);
1527 #endif
1528 #ifdef INET6
1529 	callout_drain(&sc->sc_md6_tmo);
1530 #endif
1531 	CARP_LOCK_DESTROY(sc);
1532 
1533 	free(sc->sc_ifas, M_CARP);
1534 	free(sc, M_CARP);
1535 }
1536 
1537 static struct carp_if*
1538 carp_alloc_if(struct ifnet *ifp)
1539 {
1540 	struct carp_if *cif;
1541 
1542 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1543 
1544 	if (ifpromisc(ifp, 1) != 0)
1545 		goto cleanup;
1546 
1547 	CIF_LOCK_INIT(cif);
1548 	cif->cif_ifp = ifp;
1549 	TAILQ_INIT(&cif->cif_vrs);
1550 
1551 	IF_ADDR_WLOCK(ifp);
1552 	ifp->if_carp = cif;
1553 	if_ref(ifp);
1554 	IF_ADDR_WUNLOCK(ifp);
1555 
1556 	return (cif);
1557 
1558 cleanup:
1559 	free(cif, M_CARP);
1560 
1561 	return (NULL);
1562 }
1563 
1564 static void
1565 carp_free_if(struct carp_if *cif)
1566 {
1567 	struct ifnet *ifp = cif->cif_ifp;
1568 
1569 	CIF_LOCK_ASSERT(cif);
1570 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1571 	    __func__));
1572 
1573 	IF_ADDR_WLOCK(ifp);
1574 	ifp->if_carp = NULL;
1575 	if_rele(ifp);
1576 	IF_ADDR_WUNLOCK(ifp);
1577 
1578 	CIF_LOCK_DESTROY(cif);
1579 
1580 	ifpromisc(ifp, 0);
1581 
1582 	free(cif, M_CARP);
1583 }
1584 
1585 static void
1586 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1587 {
1588 
1589 	CARP_LOCK(sc);
1590 	carpr->carpr_state = sc->sc_state;
1591 	carpr->carpr_vhid = sc->sc_vhid;
1592 	carpr->carpr_advbase = sc->sc_advbase;
1593 	carpr->carpr_advskew = sc->sc_advskew;
1594 	if (priv)
1595 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1596 	else
1597 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1598 	CARP_UNLOCK(sc);
1599 }
1600 
1601 int
1602 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1603 {
1604 	struct carpreq carpr;
1605 	struct ifnet *ifp;
1606 	struct carp_softc *sc = NULL;
1607 	int error = 0, locked = 0;
1608 
1609 	if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1610 		return (error);
1611 
1612 	ifp = ifunit_ref(ifr->ifr_name);
1613 	if (ifp == NULL)
1614 		return (ENXIO);
1615 
1616 	switch (ifp->if_type) {
1617 	case IFT_ETHER:
1618 	case IFT_L2VLAN:
1619 	case IFT_BRIDGE:
1620 	case IFT_FDDI:
1621 	case IFT_ISO88025:
1622 		break;
1623 	default:
1624 		error = EOPNOTSUPP;
1625 		goto out;
1626 	}
1627 
1628 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1629 		error = EADDRNOTAVAIL;
1630 		goto out;
1631 	}
1632 
1633 	switch (cmd) {
1634 	case SIOCSVH:
1635 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1636 			break;
1637 		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1638 		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1639 			error = EINVAL;
1640 			break;
1641 		}
1642 
1643 		if (ifp->if_carp) {
1644 			CIF_LOCK(ifp->if_carp);
1645 			IFNET_FOREACH_CARP(ifp, sc)
1646 				if (sc->sc_vhid == carpr.carpr_vhid)
1647 					break;
1648 			CIF_UNLOCK(ifp->if_carp);
1649 		}
1650 		if (sc == NULL) {
1651 			sc = carp_alloc(ifp);
1652 			if (sc == NULL) {
1653 				error = EINVAL; /* XXX: ifpromisc failed */
1654 				break;
1655 			}
1656 
1657 			CARP_LOCK(sc);
1658 			sc->sc_vhid = carpr.carpr_vhid;
1659 			LLADDR(&sc->sc_addr)[0] = 0;
1660 			LLADDR(&sc->sc_addr)[1] = 0;
1661 			LLADDR(&sc->sc_addr)[2] = 0x5e;
1662 			LLADDR(&sc->sc_addr)[3] = 0;
1663 			LLADDR(&sc->sc_addr)[4] = 1;
1664 			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1665 		} else
1666 			CARP_LOCK(sc);
1667 		locked = 1;
1668 		if (carpr.carpr_advbase > 0) {
1669 			if (carpr.carpr_advbase > 255 ||
1670 			    carpr.carpr_advbase < CARP_DFLTINTV) {
1671 				error = EINVAL;
1672 				break;
1673 			}
1674 			sc->sc_advbase = carpr.carpr_advbase;
1675 		}
1676 		if (carpr.carpr_advskew > 0) {
1677 			if (carpr.carpr_advskew >= 255) {
1678 				error = EINVAL;
1679 				break;
1680 			}
1681 			sc->sc_advskew = carpr.carpr_advskew;
1682 		}
1683 		if (carpr.carpr_key[0] != '\0') {
1684 			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1685 			carp_hmac_prepare(sc);
1686 		}
1687 		if (sc->sc_state != INIT &&
1688 		    carpr.carpr_state != sc->sc_state) {
1689 			switch (carpr.carpr_state) {
1690 			case BACKUP:
1691 				callout_stop(&sc->sc_ad_tmo);
1692 				carp_set_state(sc, BACKUP);
1693 				carp_setrun(sc, 0);
1694 				carp_delroute(sc);
1695 				break;
1696 			case MASTER:
1697 				carp_master_down_locked(sc);
1698 				break;
1699 			default:
1700 				break;
1701 			}
1702 		}
1703 		break;
1704 
1705 	case SIOCGVH:
1706 	    {
1707 		int priveleged;
1708 
1709 		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1710 			error = EINVAL;
1711 			break;
1712 		}
1713 		if (carpr.carpr_count < 1) {
1714 			error = EMSGSIZE;
1715 			break;
1716 		}
1717 		if (ifp->if_carp == NULL) {
1718 			error = ENOENT;
1719 			break;
1720 		}
1721 
1722 		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1723 		if (carpr.carpr_vhid != 0) {
1724 			CIF_LOCK(ifp->if_carp);
1725 			IFNET_FOREACH_CARP(ifp, sc)
1726 				if (sc->sc_vhid == carpr.carpr_vhid)
1727 					break;
1728 			CIF_UNLOCK(ifp->if_carp);
1729 			if (sc == NULL) {
1730 				error = ENOENT;
1731 				break;
1732 			}
1733 			carp_carprcp(&carpr, sc, priveleged);
1734 			error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
1735 		} else  {
1736 			int i, count;
1737 
1738 			count = 0;
1739 			CIF_LOCK(ifp->if_carp);
1740 			IFNET_FOREACH_CARP(ifp, sc)
1741 				count++;
1742 
1743 			if (count > carpr.carpr_count) {
1744 				CIF_UNLOCK(ifp->if_carp);
1745 				error = EMSGSIZE;
1746 				break;
1747 			}
1748 
1749 			i = 0;
1750 			IFNET_FOREACH_CARP(ifp, sc) {
1751 				carp_carprcp(&carpr, sc, priveleged);
1752 				carpr.carpr_count = count;
1753 				error = copyout(&carpr, ifr->ifr_data +
1754 				    (i * sizeof(carpr)), sizeof(carpr));
1755 				if (error) {
1756 					CIF_UNLOCK(ifp->if_carp);
1757 					break;
1758 				}
1759 				i++;
1760 			}
1761 			CIF_UNLOCK(ifp->if_carp);
1762 		}
1763 		break;
1764 	    }
1765 	default:
1766 		error = EINVAL;
1767 	}
1768 
1769 out:
1770 	if (locked)
1771 		CARP_UNLOCK(sc);
1772 	if_rele(ifp);
1773 
1774 	return (error);
1775 }
1776 
1777 static int
1778 carp_get_vhid(struct ifaddr *ifa)
1779 {
1780 
1781 	if (ifa == NULL || ifa->ifa_carp == NULL)
1782 		return (0);
1783 
1784 	return (ifa->ifa_carp->sc_vhid);
1785 }
1786 
1787 int
1788 carp_attach(struct ifaddr *ifa, int vhid)
1789 {
1790 	struct ifnet *ifp = ifa->ifa_ifp;
1791 	struct carp_if *cif = ifp->if_carp;
1792 	struct carp_softc *sc;
1793 	int index, error;
1794 
1795 	if (ifp->if_carp == NULL)
1796 		return (ENOPROTOOPT);
1797 
1798 	switch (ifa->ifa_addr->sa_family) {
1799 #ifdef INET
1800 	case AF_INET:
1801 #endif
1802 #ifdef INET6
1803 	case AF_INET6:
1804 #endif
1805 		break;
1806 	default:
1807 		return (EPROTOTYPE);
1808 	}
1809 
1810 	CIF_LOCK(cif);
1811 	IFNET_FOREACH_CARP(ifp, sc)
1812 		if (sc->sc_vhid == vhid)
1813 			break;
1814 	if (sc == NULL) {
1815 		CIF_UNLOCK(cif);
1816 		return (ENOENT);
1817 	}
1818 
1819 	if (ifa->ifa_carp) {
1820 		if (ifa->ifa_carp->sc_vhid != vhid)
1821 			carp_detach_locked(ifa);
1822 		else {
1823 			CIF_UNLOCK(cif);
1824 			return (0);
1825 		}
1826 	}
1827 
1828 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1829 	if (error) {
1830 		CIF_FREE(cif);
1831 		return (error);
1832 	}
1833 
1834 	CARP_LOCK(sc);
1835 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1836 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1837 		if ((error = carp_grow_ifas(sc)) != 0) {
1838 			carp_multicast_cleanup(cif,
1839 			    ifa->ifa_addr->sa_family);
1840 			CARP_UNLOCK(sc);
1841 			CIF_FREE(cif);
1842 			return (error);
1843 		}
1844 
1845 	switch (ifa->ifa_addr->sa_family) {
1846 #ifdef INET
1847 	case AF_INET:
1848 		cif->cif_naddrs++;
1849 		sc->sc_naddrs++;
1850 		break;
1851 #endif
1852 #ifdef INET6
1853 	case AF_INET6:
1854 		cif->cif_naddrs6++;
1855 		sc->sc_naddrs6++;
1856 		break;
1857 #endif
1858 	}
1859 
1860 	ifa_ref(ifa);
1861 	sc->sc_ifas[index - 1] = ifa;
1862 	ifa->ifa_carp = sc;
1863 
1864 	carp_hmac_prepare(sc);
1865 	carp_sc_state(sc);
1866 
1867 	CARP_UNLOCK(sc);
1868 	CIF_UNLOCK(cif);
1869 
1870 	return (0);
1871 }
1872 
1873 void
1874 carp_detach(struct ifaddr *ifa)
1875 {
1876 	struct ifnet *ifp = ifa->ifa_ifp;
1877 	struct carp_if *cif = ifp->if_carp;
1878 
1879 	CIF_LOCK(cif);
1880 	carp_detach_locked(ifa);
1881 	CIF_FREE(cif);
1882 }
1883 
1884 static void
1885 carp_detach_locked(struct ifaddr *ifa)
1886 {
1887 	struct ifnet *ifp = ifa->ifa_ifp;
1888 	struct carp_if *cif = ifp->if_carp;
1889 	struct carp_softc *sc = ifa->ifa_carp;
1890 	int i, index;
1891 
1892 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1893 
1894 	CIF_LOCK_ASSERT(cif);
1895 	CARP_LOCK(sc);
1896 
1897 	/* Shift array. */
1898 	index = sc->sc_naddrs + sc->sc_naddrs6;
1899 	for (i = 0; i < index; i++)
1900 		if (sc->sc_ifas[i] == ifa)
1901 			break;
1902 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1903 	for (; i < index - 1; i++)
1904 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1905 	sc->sc_ifas[index - 1] = NULL;
1906 
1907 	switch (ifa->ifa_addr->sa_family) {
1908 #ifdef INET
1909 	case AF_INET:
1910 		cif->cif_naddrs--;
1911 		sc->sc_naddrs--;
1912 		break;
1913 #endif
1914 #ifdef INET6
1915 	case AF_INET6:
1916 		cif->cif_naddrs6--;
1917 		sc->sc_naddrs6--;
1918 		break;
1919 #endif
1920 	}
1921 
1922 	carp_ifa_delroute(ifa);
1923 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
1924 
1925 	ifa->ifa_carp = NULL;
1926 	ifa_free(ifa);
1927 
1928 	carp_hmac_prepare(sc);
1929 	carp_sc_state(sc);
1930 
1931 	if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) {
1932 		CARP_UNLOCK(sc);
1933 		carp_destroy(sc);
1934 	} else
1935 		CARP_UNLOCK(sc);
1936 }
1937 
1938 static void
1939 carp_set_state(struct carp_softc *sc, int state)
1940 {
1941 
1942 	CARP_LOCK_ASSERT(sc);
1943 
1944 	if (sc->sc_state != state) {
1945 		const char *carp_states[] = { CARP_STATES };
1946 		char subsys[IFNAMSIZ+5];
1947 
1948 		sc->sc_state = state;
1949 
1950 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
1951 		    sc->sc_carpdev->if_xname);
1952 		devctl_notify("CARP", subsys, carp_states[state], NULL);
1953 	}
1954 }
1955 
1956 static void
1957 carp_linkstate(struct ifnet *ifp)
1958 {
1959 	struct carp_softc *sc;
1960 
1961 	CIF_LOCK(ifp->if_carp);
1962 	IFNET_FOREACH_CARP(ifp, sc) {
1963 		CARP_LOCK(sc);
1964 		carp_sc_state(sc);
1965 		CARP_UNLOCK(sc);
1966 	}
1967 	CIF_UNLOCK(ifp->if_carp);
1968 }
1969 
1970 static void
1971 carp_sc_state(struct carp_softc *sc)
1972 {
1973 
1974 	CARP_LOCK_ASSERT(sc);
1975 
1976 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1977 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
1978 		callout_stop(&sc->sc_ad_tmo);
1979 #ifdef INET
1980 		callout_stop(&sc->sc_md_tmo);
1981 #endif
1982 #ifdef INET6
1983 		callout_stop(&sc->sc_md6_tmo);
1984 #endif
1985 		carp_set_state(sc, INIT);
1986 		carp_setrun(sc, 0);
1987 		if (!sc->sc_suppress)
1988 			carp_demote_adj(carp_ifdown_adj, "interface down");
1989 		sc->sc_suppress = 1;
1990 	} else {
1991 		carp_set_state(sc, INIT);
1992 		carp_setrun(sc, 0);
1993 		if (sc->sc_suppress)
1994 			carp_demote_adj(-carp_ifdown_adj, "interface up");
1995 		sc->sc_suppress = 0;
1996 	}
1997 }
1998 
1999 static void
2000 carp_demote_adj(int adj, char *reason)
2001 {
2002 	carp_demotion += adj;
2003 	CARP_LOG("demoted by %d to %d (%s)\n", adj, carp_demotion, reason);
2004 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2005 }
2006 
2007 #ifdef INET
2008 extern  struct domain inetdomain;
2009 static struct protosw in_carp_protosw = {
2010 	.pr_type =		SOCK_RAW,
2011 	.pr_domain =		&inetdomain,
2012 	.pr_protocol =		IPPROTO_CARP,
2013 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2014 	.pr_input =		carp_input,
2015 	.pr_output =		(pr_output_t *)rip_output,
2016 	.pr_ctloutput =		rip_ctloutput,
2017 	.pr_usrreqs =		&rip_usrreqs
2018 };
2019 #endif
2020 
2021 #ifdef INET6
2022 extern	struct domain inet6domain;
2023 static struct ip6protosw in6_carp_protosw = {
2024 	.pr_type =		SOCK_RAW,
2025 	.pr_domain =		&inet6domain,
2026 	.pr_protocol =		IPPROTO_CARP,
2027 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2028 	.pr_input =		carp6_input,
2029 	.pr_output =		rip6_output,
2030 	.pr_ctloutput =		rip6_ctloutput,
2031 	.pr_usrreqs =		&rip6_usrreqs
2032 };
2033 #endif
2034 
2035 static void
2036 carp_mod_cleanup(void)
2037 {
2038 
2039 #ifdef INET
2040 	if (proto_reg[CARP_INET] == 0) {
2041 		(void)ipproto_unregister(IPPROTO_CARP);
2042 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2043 		proto_reg[CARP_INET] = -1;
2044 	}
2045 	carp_iamatch_p = NULL;
2046 #endif
2047 #ifdef INET6
2048 	if (proto_reg[CARP_INET6] == 0) {
2049 		(void)ip6proto_unregister(IPPROTO_CARP);
2050 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2051 		proto_reg[CARP_INET6] = -1;
2052 	}
2053 	carp_iamatch6_p = NULL;
2054 	carp_macmatch6_p = NULL;
2055 #endif
2056 	carp_ioctl_p = NULL;
2057 	carp_attach_p = NULL;
2058 	carp_detach_p = NULL;
2059 	carp_get_vhid_p = NULL;
2060 	carp_linkstate_p = NULL;
2061 	carp_forus_p = NULL;
2062 	carp_output_p = NULL;
2063 	carp_demote_adj_p = NULL;
2064 	mtx_unlock(&carp_mtx);
2065 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2066 	mtx_destroy(&carp_mtx);
2067 }
2068 
2069 static int
2070 carp_mod_load(void)
2071 {
2072 	int err;
2073 
2074 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2075 	LIST_INIT(&carp_list);
2076 	carp_get_vhid_p = carp_get_vhid;
2077 	carp_forus_p = carp_forus;
2078 	carp_output_p = carp_output;
2079 	carp_linkstate_p = carp_linkstate;
2080 	carp_ioctl_p = carp_ioctl;
2081 	carp_attach_p = carp_attach;
2082 	carp_detach_p = carp_detach;
2083 	carp_demote_adj_p = carp_demote_adj;
2084 #ifdef INET6
2085 	carp_iamatch6_p = carp_iamatch6;
2086 	carp_macmatch6_p = carp_macmatch6;
2087 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2088 	    (struct protosw *)&in6_carp_protosw);
2089 	if (proto_reg[CARP_INET6]) {
2090 		printf("carp: error %d attaching to PF_INET6\n",
2091 		    proto_reg[CARP_INET6]);
2092 		carp_mod_cleanup();
2093 		return (proto_reg[CARP_INET6]);
2094 	}
2095 	err = ip6proto_register(IPPROTO_CARP);
2096 	if (err) {
2097 		printf("carp: error %d registering with INET6\n", err);
2098 		carp_mod_cleanup();
2099 		return (err);
2100 	}
2101 #endif
2102 #ifdef INET
2103 	carp_iamatch_p = carp_iamatch;
2104 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2105 	if (proto_reg[CARP_INET]) {
2106 		printf("carp: error %d attaching to PF_INET\n",
2107 		    proto_reg[CARP_INET]);
2108 		carp_mod_cleanup();
2109 		return (proto_reg[CARP_INET]);
2110 	}
2111 	err = ipproto_register(IPPROTO_CARP);
2112 	if (err) {
2113 		printf("carp: error %d registering with INET\n", err);
2114 		carp_mod_cleanup();
2115 		return (err);
2116 	}
2117 #endif
2118 	return (0);
2119 }
2120 
2121 static int
2122 carp_modevent(module_t mod, int type, void *data)
2123 {
2124 	switch (type) {
2125 	case MOD_LOAD:
2126 		return carp_mod_load();
2127 		/* NOTREACHED */
2128 	case MOD_UNLOAD:
2129 		mtx_lock(&carp_mtx);
2130 		if (LIST_EMPTY(&carp_list))
2131 			carp_mod_cleanup();
2132 		else {
2133 			mtx_unlock(&carp_mtx);
2134 			return (EBUSY);
2135 		}
2136 		break;
2137 
2138 	default:
2139 		return (EINVAL);
2140 	}
2141 
2142 	return (0);
2143 }
2144 
2145 static moduledata_t carp_mod = {
2146 	"carp",
2147 	carp_modevent,
2148 	0
2149 };
2150 
2151 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2152