xref: /freebsd/sys/netinet/ip_carp.c (revision 1ab64a6127a184af40fdb4c13a39019a76a57216)
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 #include <sys/counter.h>
54 
55 #include <net/ethernet.h>
56 #include <net/fddi.h>
57 #include <net/if.h>
58 #include <net/if_var.h>
59 #include <net/if_dl.h>
60 #include <net/if_llatbl.h>
61 #include <net/if_types.h>
62 #include <net/iso88025.h>
63 #include <net/route.h>
64 #include <net/vnet.h>
65 
66 #if defined(INET) || defined(INET6)
67 #include <netinet/in.h>
68 #include <netinet/in_var.h>
69 #include <netinet/ip_carp.h>
70 #include <netinet/ip.h>
71 #include <machine/in_cksum.h>
72 #endif
73 #ifdef INET
74 #include <netinet/ip_var.h>
75 #include <netinet/if_ether.h>
76 #endif
77 
78 #ifdef INET6
79 #include <netinet/icmp6.h>
80 #include <netinet/ip6.h>
81 #include <netinet6/in6_var.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 
89 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
90 
91 struct carp_softc {
92 	struct ifnet		*sc_carpdev;	/* Pointer to parent ifnet. */
93 	struct ifaddr		**sc_ifas;	/* Our ifaddrs. */
94 	struct sockaddr_dl	sc_addr;	/* Our link level address. */
95 	struct callout		sc_ad_tmo;	/* Advertising timeout. */
96 #ifdef INET
97 	struct callout		sc_md_tmo;	/* Master down timeout. */
98 #endif
99 #ifdef INET6
100 	struct callout 		sc_md6_tmo;	/* XXX: Master down timeout. */
101 #endif
102 	struct mtx		sc_mtx;
103 
104 	int			sc_vhid;
105 	int			sc_advskew;
106 	int			sc_advbase;
107 
108 	int			sc_naddrs;
109 	int			sc_naddrs6;
110 	int			sc_ifasiz;
111 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
112 	int			sc_suppress;
113 	int			sc_sendad_errors;
114 #define	CARP_SENDAD_MAX_ERRORS	3
115 	int			sc_sendad_success;
116 #define	CARP_SENDAD_MIN_SUCCESS 3
117 
118 	int			sc_init_counter;
119 	uint64_t		sc_counter;
120 
121 	/* authentication */
122 #define	CARP_HMAC_PAD	64
123 	unsigned char sc_key[CARP_KEY_LEN];
124 	unsigned char sc_pad[CARP_HMAC_PAD];
125 	SHA1_CTX sc_sha1;
126 
127 	TAILQ_ENTRY(carp_softc)	sc_list;	/* On the carp_if list. */
128 	LIST_ENTRY(carp_softc)	sc_next;	/* On the global list. */
129 };
130 
131 struct carp_if {
132 #ifdef INET
133 	int	cif_naddrs;
134 #endif
135 #ifdef INET6
136 	int	cif_naddrs6;
137 #endif
138 	TAILQ_HEAD(, carp_softc) cif_vrs;
139 #ifdef INET
140 	struct ip_moptions 	 cif_imo;
141 #endif
142 #ifdef INET6
143 	struct ip6_moptions 	 cif_im6o;
144 #endif
145 	struct ifnet	*cif_ifp;
146 	struct mtx	cif_mtx;
147 	uint32_t	cif_flags;
148 #define	CIF_PROMISC	0x00000001
149 };
150 
151 #define	CARP_INET	0
152 #define	CARP_INET6	1
153 static int proto_reg[] = {-1, -1};
154 
155 /*
156  * Brief design of carp(4).
157  *
158  * Any carp-capable ifnet may have a list of carp softcs hanging off
159  * its ifp->if_carp pointer. Each softc represents one unique virtual
160  * host id, or vhid. The softc has a back pointer to the ifnet. All
161  * softcs are joined in a global list, which has quite limited use.
162  *
163  * Any interface address that takes part in CARP negotiation has a
164  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
165  * AF_INET or AF_INET6 address.
166  *
167  * Although, one can get the softc's backpointer to ifnet and traverse
168  * through its ifp->if_addrhead queue to find all interface addresses
169  * involved in CARP, we keep a growable array of ifaddr pointers. This
170  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
171  * do calls into the network stack, thus avoiding LORs.
172  *
173  * Locking:
174  *
175  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
176  * callout-driven events and ioctl()s.
177  *
178  * To traverse the list of softcs on an ifnet we use CIF_LOCK(), to
179  * traverse the global list we use the mutex carp_mtx.
180  *
181  * Known issues with locking:
182  *
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 /* Accept incoming CARP packets. */
190 static VNET_DEFINE(int, carp_allow) = 1;
191 #define	V_carp_allow	VNET(carp_allow)
192 
193 /* Preempt slower nodes. */
194 static VNET_DEFINE(int, carp_preempt) = 0;
195 #define	V_carp_preempt	VNET(carp_preempt)
196 
197 /* Log level. */
198 static VNET_DEFINE(int, carp_log) = 1;
199 #define	V_carp_log	VNET(carp_log)
200 
201 /* Global advskew demotion. */
202 static VNET_DEFINE(int, carp_demotion) = 0;
203 #define	V_carp_demotion	VNET(carp_demotion)
204 
205 /* Send error demotion factor. */
206 static VNET_DEFINE(int, carp_senderr_adj) = CARP_MAXSKEW;
207 #define	V_carp_senderr_adj	VNET(carp_senderr_adj)
208 
209 /* Iface down demotion factor. */
210 static VNET_DEFINE(int, carp_ifdown_adj) = CARP_MAXSKEW;
211 #define	V_carp_ifdown_adj	VNET(carp_ifdown_adj)
212 
213 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
214 
215 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
216 SYSCTL_INT(_net_inet_carp, OID_AUTO, allow, CTLFLAG_VNET | CTLFLAG_RW,
217     &VNET_NAME(carp_allow), 0, "Accept incoming CARP packets");
218 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
219     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
220 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
221     &VNET_NAME(carp_log), 0, "CARP log level");
222 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
223     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW,
224     0, 0, carp_demote_adj_sysctl, "I",
225     "Adjust demotion factor (skew of advskew)");
226 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
227     CTLFLAG_VNET | CTLFLAG_RW,
228     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
229 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
230     CTLFLAG_VNET | CTLFLAG_RW,
231     &VNET_NAME(carp_ifdown_adj), 0,
232     "Interface down demotion factor adjustment");
233 
234 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
235 VNET_PCPUSTAT_SYSINIT(carpstats);
236 VNET_PCPUSTAT_SYSUNINIT(carpstats);
237 
238 #define	CARPSTATS_ADD(name, val)	\
239     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
240 	sizeof(uint64_t)], (val))
241 #define	CARPSTATS_INC(name)		CARPSTATS_ADD(name, 1)
242 
243 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
244     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
245 
246 #define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
247 	NULL, MTX_DEF)
248 #define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
249 #define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
250 #define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
251 #define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
252 #define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
253 	NULL, MTX_DEF)
254 #define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
255 #define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
256 #define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
257 #define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
258 #define	CIF_FREE(cif)	do {				\
259 		CIF_LOCK_ASSERT(cif);			\
260 		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
261 			carp_free_if(cif);		\
262 		else					\
263 			CIF_UNLOCK(cif);		\
264 } while (0)
265 
266 #define	CARP_LOG(...)	do {				\
267 	if (V_carp_log > 0)				\
268 		log(LOG_INFO, "carp: " __VA_ARGS__);	\
269 } while (0)
270 
271 #define	CARP_DEBUG(...)	do {				\
272 	if (V_carp_log > 1)				\
273 		log(LOG_DEBUG, __VA_ARGS__);		\
274 } while (0)
275 
276 #define	IFNET_FOREACH_IFA(ifp, ifa)					\
277 	IF_ADDR_LOCK_ASSERT(ifp);					\
278 	TAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)		\
279 		if ((ifa)->ifa_carp != NULL)
280 
281 #define	CARP_FOREACH_IFA(sc, ifa)					\
282 	CARP_LOCK_ASSERT(sc);						\
283 	for (int _i = 0;						\
284 		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
285 		((ifa) = sc->sc_ifas[_i]) != NULL;			\
286 		++_i)
287 
288 #define	IFNET_FOREACH_CARP(ifp, sc)					\
289 	CIF_LOCK_ASSERT(ifp->if_carp);					\
290 	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
291 
292 #define	DEMOTE_ADVSKEW(sc)					\
293     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?	\
294     CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion))
295 
296 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
297 static struct carp_softc
298 		*carp_alloc(struct ifnet *);
299 static void	carp_detach_locked(struct ifaddr *);
300 static void	carp_destroy(struct carp_softc *);
301 static struct carp_if
302 		*carp_alloc_if(struct ifnet *);
303 static void	carp_free_if(struct carp_if *);
304 static void	carp_set_state(struct carp_softc *, int, const char* reason);
305 static void	carp_sc_state(struct carp_softc *);
306 static void	carp_setrun(struct carp_softc *, sa_family_t);
307 static void	carp_master_down(void *);
308 static void	carp_master_down_locked(struct carp_softc *,
309     		    const char* reason);
310 static void	carp_send_ad(void *);
311 static void	carp_send_ad_locked(struct carp_softc *);
312 static void	carp_addroute(struct carp_softc *);
313 static void	carp_ifa_addroute(struct ifaddr *);
314 static void	carp_delroute(struct carp_softc *);
315 static void	carp_ifa_delroute(struct ifaddr *);
316 static void	carp_send_ad_all(void *, int);
317 static void	carp_demote_adj(int, char *);
318 
319 static LIST_HEAD(, carp_softc) carp_list;
320 static struct mtx carp_mtx;
321 static struct sx carp_sx;
322 static struct task carp_sendall_task =
323     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
324 
325 static void
326 carp_hmac_prepare(struct carp_softc *sc)
327 {
328 	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
329 	uint8_t vhid = sc->sc_vhid & 0xff;
330 	struct ifaddr *ifa;
331 	int i, found;
332 #ifdef INET
333 	struct in_addr last, cur, in;
334 #endif
335 #ifdef INET6
336 	struct in6_addr last6, cur6, in6;
337 #endif
338 
339 	CARP_LOCK_ASSERT(sc);
340 
341 	/* Compute ipad from key. */
342 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
343 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
344 	for (i = 0; i < sizeof(sc->sc_pad); i++)
345 		sc->sc_pad[i] ^= 0x36;
346 
347 	/* Precompute first part of inner hash. */
348 	SHA1Init(&sc->sc_sha1);
349 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
350 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
351 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
352 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
353 #ifdef INET
354 	cur.s_addr = 0;
355 	do {
356 		found = 0;
357 		last = cur;
358 		cur.s_addr = 0xffffffff;
359 		CARP_FOREACH_IFA(sc, ifa) {
360 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
361 			if (ifa->ifa_addr->sa_family == AF_INET &&
362 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
363 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
364 				cur.s_addr = in.s_addr;
365 				found++;
366 			}
367 		}
368 		if (found)
369 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
370 	} while (found);
371 #endif /* INET */
372 #ifdef INET6
373 	memset(&cur6, 0, sizeof(cur6));
374 	do {
375 		found = 0;
376 		last6 = cur6;
377 		memset(&cur6, 0xff, sizeof(cur6));
378 		CARP_FOREACH_IFA(sc, ifa) {
379 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
380 			if (IN6_IS_SCOPE_EMBED(&in6))
381 				in6.s6_addr16[1] = 0;
382 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
383 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
384 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
385 				cur6 = in6;
386 				found++;
387 			}
388 		}
389 		if (found)
390 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
391 	} while (found);
392 #endif /* INET6 */
393 
394 	/* convert ipad to opad */
395 	for (i = 0; i < sizeof(sc->sc_pad); i++)
396 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
397 }
398 
399 static void
400 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
401     unsigned char md[20])
402 {
403 	SHA1_CTX sha1ctx;
404 
405 	CARP_LOCK_ASSERT(sc);
406 
407 	/* fetch first half of inner hash */
408 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
409 
410 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
411 	SHA1Final(md, &sha1ctx);
412 
413 	/* outer hash */
414 	SHA1Init(&sha1ctx);
415 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
416 	SHA1Update(&sha1ctx, md, 20);
417 	SHA1Final(md, &sha1ctx);
418 }
419 
420 static int
421 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
422     unsigned char md[20])
423 {
424 	unsigned char md2[20];
425 
426 	CARP_LOCK_ASSERT(sc);
427 
428 	carp_hmac_generate(sc, counter, md2);
429 
430 	return (bcmp(md, md2, sizeof(md2)));
431 }
432 
433 /*
434  * process input packet.
435  * we have rearranged checks order compared to the rfc,
436  * but it seems more efficient this way or not possible otherwise.
437  */
438 #ifdef INET
439 int
440 carp_input(struct mbuf **mp, int *offp, int proto)
441 {
442 	struct mbuf *m = *mp;
443 	struct ip *ip = mtod(m, struct ip *);
444 	struct carp_header *ch;
445 	int iplen, len;
446 
447 	iplen = *offp;
448 	*mp = NULL;
449 
450 	CARPSTATS_INC(carps_ipackets);
451 
452 	if (!V_carp_allow) {
453 		m_freem(m);
454 		return (IPPROTO_DONE);
455 	}
456 
457 	/* verify that the IP TTL is 255.  */
458 	if (ip->ip_ttl != CARP_DFLTTL) {
459 		CARPSTATS_INC(carps_badttl);
460 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
461 		    ip->ip_ttl,
462 		    m->m_pkthdr.rcvif->if_xname);
463 		m_freem(m);
464 		return (IPPROTO_DONE);
465 	}
466 
467 	iplen = ip->ip_hl << 2;
468 
469 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
470 		CARPSTATS_INC(carps_badlen);
471 		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
472 		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
473 		    m->m_pkthdr.rcvif->if_xname);
474 		m_freem(m);
475 		return (IPPROTO_DONE);
476 	}
477 
478 	if (iplen + sizeof(*ch) < m->m_len) {
479 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
480 			CARPSTATS_INC(carps_hdrops);
481 			CARP_DEBUG("%s: pullup failed\n", __func__);
482 			return (IPPROTO_DONE);
483 		}
484 		ip = mtod(m, struct ip *);
485 	}
486 	ch = (struct carp_header *)((char *)ip + iplen);
487 
488 	/*
489 	 * verify that the received packet length is
490 	 * equal to the CARP header
491 	 */
492 	len = iplen + sizeof(*ch);
493 	if (len > m->m_pkthdr.len) {
494 		CARPSTATS_INC(carps_badlen);
495 		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
496 		    m->m_pkthdr.len,
497 		    m->m_pkthdr.rcvif->if_xname);
498 		m_freem(m);
499 		return (IPPROTO_DONE);
500 	}
501 
502 	if ((m = m_pullup(m, len)) == NULL) {
503 		CARPSTATS_INC(carps_hdrops);
504 		return (IPPROTO_DONE);
505 	}
506 	ip = mtod(m, struct ip *);
507 	ch = (struct carp_header *)((char *)ip + iplen);
508 
509 	/* verify the CARP checksum */
510 	m->m_data += iplen;
511 	if (in_cksum(m, len - iplen)) {
512 		CARPSTATS_INC(carps_badsum);
513 		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
514 		    m->m_pkthdr.rcvif->if_xname);
515 		m_freem(m);
516 		return (IPPROTO_DONE);
517 	}
518 	m->m_data -= iplen;
519 
520 	carp_input_c(m, ch, AF_INET);
521 	return (IPPROTO_DONE);
522 }
523 #endif
524 
525 #ifdef INET6
526 int
527 carp6_input(struct mbuf **mp, int *offp, int proto)
528 {
529 	struct mbuf *m = *mp;
530 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
531 	struct carp_header *ch;
532 	u_int len;
533 
534 	CARPSTATS_INC(carps_ipackets6);
535 
536 	if (!V_carp_allow) {
537 		m_freem(m);
538 		return (IPPROTO_DONE);
539 	}
540 
541 	/* check if received on a valid carp interface */
542 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
543 		CARPSTATS_INC(carps_badif);
544 		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
545 		    __func__, m->m_pkthdr.rcvif->if_xname);
546 		m_freem(m);
547 		return (IPPROTO_DONE);
548 	}
549 
550 	/* verify that the IP TTL is 255 */
551 	if (ip6->ip6_hlim != CARP_DFLTTL) {
552 		CARPSTATS_INC(carps_badttl);
553 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
554 		    ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
555 		m_freem(m);
556 		return (IPPROTO_DONE);
557 	}
558 
559 	/* verify that we have a complete carp packet */
560 	len = m->m_len;
561 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
562 	if (ch == NULL) {
563 		CARPSTATS_INC(carps_badlen);
564 		CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
565 		return (IPPROTO_DONE);
566 	}
567 
568 
569 	/* verify the CARP checksum */
570 	m->m_data += *offp;
571 	if (in_cksum(m, sizeof(*ch))) {
572 		CARPSTATS_INC(carps_badsum);
573 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
574 		    m->m_pkthdr.rcvif->if_xname);
575 		m_freem(m);
576 		return (IPPROTO_DONE);
577 	}
578 	m->m_data -= *offp;
579 
580 	carp_input_c(m, ch, AF_INET6);
581 	return (IPPROTO_DONE);
582 }
583 #endif /* INET6 */
584 
585 static void
586 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
587 {
588 	struct ifnet *ifp = m->m_pkthdr.rcvif;
589 	struct ifaddr *ifa;
590 	struct carp_softc *sc;
591 	uint64_t tmp_counter;
592 	struct timeval sc_tv, ch_tv;
593 
594 	/* verify that the VHID is valid on the receiving interface */
595 	IF_ADDR_RLOCK(ifp);
596 	IFNET_FOREACH_IFA(ifp, ifa)
597 		if (ifa->ifa_addr->sa_family == af &&
598 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid) {
599 			ifa_ref(ifa);
600 			break;
601 		}
602 	IF_ADDR_RUNLOCK(ifp);
603 
604 	if (ifa == NULL) {
605 		CARPSTATS_INC(carps_badvhid);
606 		m_freem(m);
607 		return;
608 	}
609 
610 	/* verify the CARP version. */
611 	if (ch->carp_version != CARP_VERSION) {
612 		CARPSTATS_INC(carps_badver);
613 		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
614 		    ch->carp_version);
615 		ifa_free(ifa);
616 		m_freem(m);
617 		return;
618 	}
619 
620 	sc = ifa->ifa_carp;
621 	CARP_LOCK(sc);
622 	ifa_free(ifa);
623 
624 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
625 		CARPSTATS_INC(carps_badauth);
626 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
627 		    sc->sc_vhid, ifp->if_xname);
628 		goto out;
629 	}
630 
631 	tmp_counter = ntohl(ch->carp_counter[0]);
632 	tmp_counter = tmp_counter<<32;
633 	tmp_counter += ntohl(ch->carp_counter[1]);
634 
635 	/* XXX Replay protection goes here */
636 
637 	sc->sc_init_counter = 0;
638 	sc->sc_counter = tmp_counter;
639 
640 	sc_tv.tv_sec = sc->sc_advbase;
641 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
642 	ch_tv.tv_sec = ch->carp_advbase;
643 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
644 
645 	switch (sc->sc_state) {
646 	case INIT:
647 		break;
648 	case MASTER:
649 		/*
650 		 * If we receive an advertisement from a master who's going to
651 		 * be more frequent than us, go into BACKUP state.
652 		 */
653 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
654 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
655 			callout_stop(&sc->sc_ad_tmo);
656 			carp_set_state(sc, BACKUP,
657 			    "more frequent advertisement received");
658 			carp_setrun(sc, 0);
659 			carp_delroute(sc);
660 		}
661 		break;
662 	case BACKUP:
663 		/*
664 		 * If we're pre-empting masters who advertise slower than us,
665 		 * and this one claims to be slower, treat him as down.
666 		 */
667 		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
668 			carp_master_down_locked(sc,
669 			    "preempting a slower master");
670 			break;
671 		}
672 
673 		/*
674 		 *  If the master is going to advertise at such a low frequency
675 		 *  that he's guaranteed to time out, we'd might as well just
676 		 *  treat him as timed out now.
677 		 */
678 		sc_tv.tv_sec = sc->sc_advbase * 3;
679 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
680 			carp_master_down_locked(sc, "master will time out");
681 			break;
682 		}
683 
684 		/*
685 		 * Otherwise, we reset the counter and wait for the next
686 		 * advertisement.
687 		 */
688 		carp_setrun(sc, af);
689 		break;
690 	}
691 
692 out:
693 	CARP_UNLOCK(sc);
694 	m_freem(m);
695 }
696 
697 static int
698 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
699 {
700 	struct m_tag *mtag;
701 
702 	if (sc->sc_init_counter) {
703 		/* this could also be seconds since unix epoch */
704 		sc->sc_counter = arc4random();
705 		sc->sc_counter = sc->sc_counter << 32;
706 		sc->sc_counter += arc4random();
707 	} else
708 		sc->sc_counter++;
709 
710 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
711 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
712 
713 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
714 
715 	/* Tag packet for carp_output */
716 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
717 	    M_NOWAIT)) == NULL) {
718 		m_freem(m);
719 		CARPSTATS_INC(carps_onomem);
720 		return (ENOMEM);
721 	}
722 	bcopy(&sc, mtag + 1, sizeof(sc));
723 	m_tag_prepend(m, mtag);
724 
725 	return (0);
726 }
727 
728 /*
729  * To avoid LORs and possible recursions this function shouldn't
730  * be called directly, but scheduled via taskqueue.
731  */
732 static void
733 carp_send_ad_all(void *ctx __unused, int pending __unused)
734 {
735 	struct carp_softc *sc;
736 
737 	mtx_lock(&carp_mtx);
738 	LIST_FOREACH(sc, &carp_list, sc_next)
739 		if (sc->sc_state == MASTER) {
740 			CARP_LOCK(sc);
741 			CURVNET_SET(sc->sc_carpdev->if_vnet);
742 			carp_send_ad_locked(sc);
743 			CURVNET_RESTORE();
744 			CARP_UNLOCK(sc);
745 		}
746 	mtx_unlock(&carp_mtx);
747 }
748 
749 /* Send a periodic advertisement, executed in callout context. */
750 static void
751 carp_send_ad(void *v)
752 {
753 	struct carp_softc *sc = v;
754 
755 	CARP_LOCK_ASSERT(sc);
756 	CURVNET_SET(sc->sc_carpdev->if_vnet);
757 	carp_send_ad_locked(sc);
758 	CURVNET_RESTORE();
759 	CARP_UNLOCK(sc);
760 }
761 
762 static void
763 carp_send_ad_error(struct carp_softc *sc, int error)
764 {
765 
766 	if (error) {
767 		if (sc->sc_sendad_errors < INT_MAX)
768 			sc->sc_sendad_errors++;
769 		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
770 			static const char fmt[] = "send error %d on %s";
771 			char msg[sizeof(fmt) + IFNAMSIZ];
772 
773 			sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
774 			carp_demote_adj(V_carp_senderr_adj, msg);
775 		}
776 		sc->sc_sendad_success = 0;
777 	} else {
778 		if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
779 		    ++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
780 			static const char fmt[] = "send ok on %s";
781 			char msg[sizeof(fmt) + IFNAMSIZ];
782 
783 			sprintf(msg, fmt, sc->sc_carpdev->if_xname);
784 			carp_demote_adj(-V_carp_senderr_adj, msg);
785 			sc->sc_sendad_errors = 0;
786 		} else
787 			sc->sc_sendad_errors = 0;
788 	}
789 }
790 
791 static void
792 carp_send_ad_locked(struct carp_softc *sc)
793 {
794 	struct carp_header ch;
795 	struct timeval tv;
796 	struct sockaddr sa;
797 	struct ifaddr *ifa;
798 	struct carp_header *ch_ptr;
799 	struct mbuf *m;
800 	int len, advskew;
801 
802 	CARP_LOCK_ASSERT(sc);
803 
804 	advskew = DEMOTE_ADVSKEW(sc);
805 	tv.tv_sec = sc->sc_advbase;
806 	tv.tv_usec = advskew * 1000000 / 256;
807 
808 	ch.carp_version = CARP_VERSION;
809 	ch.carp_type = CARP_ADVERTISEMENT;
810 	ch.carp_vhid = sc->sc_vhid;
811 	ch.carp_advbase = sc->sc_advbase;
812 	ch.carp_advskew = advskew;
813 	ch.carp_authlen = 7;	/* XXX DEFINE */
814 	ch.carp_pad1 = 0;	/* must be zero */
815 	ch.carp_cksum = 0;
816 
817 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
818 
819 #ifdef INET
820 	if (sc->sc_naddrs) {
821 		struct ip *ip;
822 
823 		m = m_gethdr(M_NOWAIT, MT_DATA);
824 		if (m == NULL) {
825 			CARPSTATS_INC(carps_onomem);
826 			goto resched;
827 		}
828 		len = sizeof(*ip) + sizeof(ch);
829 		m->m_pkthdr.len = len;
830 		m->m_pkthdr.rcvif = NULL;
831 		m->m_len = len;
832 		M_ALIGN(m, m->m_len);
833 		m->m_flags |= M_MCAST;
834 		ip = mtod(m, struct ip *);
835 		ip->ip_v = IPVERSION;
836 		ip->ip_hl = sizeof(*ip) >> 2;
837 		ip->ip_tos = IPTOS_LOWDELAY;
838 		ip->ip_len = htons(len);
839 		ip->ip_off = htons(IP_DF);
840 		ip->ip_ttl = CARP_DFLTTL;
841 		ip->ip_p = IPPROTO_CARP;
842 		ip->ip_sum = 0;
843 		ip_fillid(ip);
844 
845 		bzero(&sa, sizeof(sa));
846 		sa.sa_family = AF_INET;
847 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
848 		if (ifa != NULL) {
849 			ip->ip_src.s_addr =
850 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
851 			ifa_free(ifa);
852 		} else
853 			ip->ip_src.s_addr = 0;
854 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
855 
856 		ch_ptr = (struct carp_header *)(&ip[1]);
857 		bcopy(&ch, ch_ptr, sizeof(ch));
858 		if (carp_prepare_ad(m, sc, ch_ptr))
859 			goto resched;
860 
861 		m->m_data += sizeof(*ip);
862 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
863 		m->m_data -= sizeof(*ip);
864 
865 		CARPSTATS_INC(carps_opackets);
866 
867 		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
868 		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
869 	}
870 #endif /* INET */
871 #ifdef INET6
872 	if (sc->sc_naddrs6) {
873 		struct ip6_hdr *ip6;
874 
875 		m = m_gethdr(M_NOWAIT, MT_DATA);
876 		if (m == NULL) {
877 			CARPSTATS_INC(carps_onomem);
878 			goto resched;
879 		}
880 		len = sizeof(*ip6) + sizeof(ch);
881 		m->m_pkthdr.len = len;
882 		m->m_pkthdr.rcvif = NULL;
883 		m->m_len = len;
884 		M_ALIGN(m, m->m_len);
885 		m->m_flags |= M_MCAST;
886 		ip6 = mtod(m, struct ip6_hdr *);
887 		bzero(ip6, sizeof(*ip6));
888 		ip6->ip6_vfc |= IPV6_VERSION;
889 		ip6->ip6_hlim = CARP_DFLTTL;
890 		ip6->ip6_nxt = IPPROTO_CARP;
891 		bzero(&sa, sizeof(sa));
892 
893 		/* set the source address */
894 		sa.sa_family = AF_INET6;
895 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
896 		if (ifa != NULL) {
897 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
898 			    sizeof(struct in6_addr));
899 			ifa_free(ifa);
900 		} else
901 			/* This should never happen with IPv6. */
902 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
903 
904 		/* Set the multicast destination. */
905 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
906 		ip6->ip6_dst.s6_addr8[15] = 0x12;
907 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
908 			m_freem(m);
909 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
910 			goto resched;
911 		}
912 
913 		ch_ptr = (struct carp_header *)(&ip6[1]);
914 		bcopy(&ch, ch_ptr, sizeof(ch));
915 		if (carp_prepare_ad(m, sc, ch_ptr))
916 			goto resched;
917 
918 		m->m_data += sizeof(*ip6);
919 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
920 		m->m_data -= sizeof(*ip6);
921 
922 		CARPSTATS_INC(carps_opackets6);
923 
924 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
925 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
926 	}
927 #endif /* INET6 */
928 
929 resched:
930 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
931 }
932 
933 static void
934 carp_addroute(struct carp_softc *sc)
935 {
936 	struct ifaddr *ifa;
937 
938 	CARP_FOREACH_IFA(sc, ifa)
939 		carp_ifa_addroute(ifa);
940 }
941 
942 static void
943 carp_ifa_addroute(struct ifaddr *ifa)
944 {
945 
946 	switch (ifa->ifa_addr->sa_family) {
947 #ifdef INET
948 	case AF_INET:
949 		in_addprefix(ifatoia(ifa), RTF_UP);
950 		ifa_add_loopback_route(ifa,
951 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
952 		break;
953 #endif
954 #ifdef INET6
955 	case AF_INET6:
956 		ifa_add_loopback_route(ifa,
957 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
958 		nd6_add_ifa_lle(ifatoia6(ifa));
959 		break;
960 #endif
961 	}
962 }
963 
964 static void
965 carp_delroute(struct carp_softc *sc)
966 {
967 	struct ifaddr *ifa;
968 
969 	CARP_FOREACH_IFA(sc, ifa)
970 		carp_ifa_delroute(ifa);
971 }
972 
973 static void
974 carp_ifa_delroute(struct ifaddr *ifa)
975 {
976 
977 	switch (ifa->ifa_addr->sa_family) {
978 #ifdef INET
979 	case AF_INET:
980 		ifa_del_loopback_route(ifa,
981 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
982 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
983 		break;
984 #endif
985 #ifdef INET6
986 	case AF_INET6:
987 		ifa_del_loopback_route(ifa,
988 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
989 		nd6_rem_ifa_lle(ifatoia6(ifa));
990 		break;
991 #endif
992 	}
993 }
994 
995 int
996 carp_master(struct ifaddr *ifa)
997 {
998 	struct carp_softc *sc = ifa->ifa_carp;
999 
1000 	return (sc->sc_state == MASTER);
1001 }
1002 
1003 #ifdef INET
1004 /*
1005  * Broadcast a gratuitous ARP request containing
1006  * the virtual router MAC address for each IP address
1007  * associated with the virtual router.
1008  */
1009 static void
1010 carp_send_arp(struct carp_softc *sc)
1011 {
1012 	struct ifaddr *ifa;
1013 
1014 	CARP_FOREACH_IFA(sc, ifa)
1015 		if (ifa->ifa_addr->sa_family == AF_INET)
1016 			arp_ifinit2(sc->sc_carpdev, ifa, LLADDR(&sc->sc_addr));
1017 }
1018 
1019 int
1020 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1021 {
1022 	struct carp_softc *sc = ifa->ifa_carp;
1023 
1024 	if (sc->sc_state == MASTER) {
1025 		*enaddr = LLADDR(&sc->sc_addr);
1026 		return (1);
1027 	}
1028 
1029 	return (0);
1030 }
1031 #endif
1032 
1033 #ifdef INET6
1034 static void
1035 carp_send_na(struct carp_softc *sc)
1036 {
1037 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1038 	struct ifaddr *ifa;
1039 	struct in6_addr *in6;
1040 
1041 	CARP_FOREACH_IFA(sc, ifa) {
1042 		if (ifa->ifa_addr->sa_family != AF_INET6)
1043 			continue;
1044 
1045 		in6 = IFA_IN6(ifa);
1046 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1047 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1048 		DELAY(1000);	/* XXX */
1049 	}
1050 }
1051 
1052 /*
1053  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1054  * matches and is not a carp address.  Returns NULL otherwise.
1055  */
1056 struct ifaddr *
1057 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1058 {
1059 	struct ifaddr *ifa;
1060 
1061 	ifa = NULL;
1062 	IF_ADDR_RLOCK(ifp);
1063 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1064 		if (ifa->ifa_addr->sa_family != AF_INET6)
1065 			continue;
1066 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1067 			continue;
1068 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1069 			ifa = NULL;
1070 		else
1071 			ifa_ref(ifa);
1072 		break;
1073 	}
1074 	IF_ADDR_RUNLOCK(ifp);
1075 
1076 	return (ifa);
1077 }
1078 
1079 caddr_t
1080 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1081 {
1082 	struct ifaddr *ifa;
1083 
1084 	IF_ADDR_RLOCK(ifp);
1085 	IFNET_FOREACH_IFA(ifp, ifa)
1086 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1087 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1088 			struct carp_softc *sc = ifa->ifa_carp;
1089 			struct m_tag *mtag;
1090 
1091 			IF_ADDR_RUNLOCK(ifp);
1092 
1093 			mtag = m_tag_get(PACKET_TAG_CARP,
1094 			    sizeof(struct carp_softc *), M_NOWAIT);
1095 			if (mtag == NULL)
1096 				/* Better a bit than nothing. */
1097 				return (LLADDR(&sc->sc_addr));
1098 
1099 			bcopy(&sc, mtag + 1, sizeof(sc));
1100 			m_tag_prepend(m, mtag);
1101 
1102 			return (LLADDR(&sc->sc_addr));
1103 		}
1104 	IF_ADDR_RUNLOCK(ifp);
1105 
1106 	return (NULL);
1107 }
1108 #endif /* INET6 */
1109 
1110 int
1111 carp_forus(struct ifnet *ifp, u_char *dhost)
1112 {
1113 	struct carp_softc *sc;
1114 	uint8_t *ena = dhost;
1115 
1116 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1117 		return (0);
1118 
1119 	CIF_LOCK(ifp->if_carp);
1120 	IFNET_FOREACH_CARP(ifp, sc) {
1121 		CARP_LOCK(sc);
1122 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1123 		    ETHER_ADDR_LEN)) {
1124 			CARP_UNLOCK(sc);
1125 			CIF_UNLOCK(ifp->if_carp);
1126 			return (1);
1127 		}
1128 		CARP_UNLOCK(sc);
1129 	}
1130 	CIF_UNLOCK(ifp->if_carp);
1131 
1132 	return (0);
1133 }
1134 
1135 /* Master down timeout event, executed in callout context. */
1136 static void
1137 carp_master_down(void *v)
1138 {
1139 	struct carp_softc *sc = v;
1140 
1141 	CARP_LOCK_ASSERT(sc);
1142 
1143 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1144 	if (sc->sc_state == BACKUP) {
1145 		carp_master_down_locked(sc, "master timed out");
1146 	}
1147 	CURVNET_RESTORE();
1148 
1149 	CARP_UNLOCK(sc);
1150 }
1151 
1152 static void
1153 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1154 {
1155 
1156 	CARP_LOCK_ASSERT(sc);
1157 
1158 	switch (sc->sc_state) {
1159 	case BACKUP:
1160 		carp_set_state(sc, MASTER, reason);
1161 		carp_send_ad_locked(sc);
1162 #ifdef INET
1163 		carp_send_arp(sc);
1164 #endif
1165 #ifdef INET6
1166 		carp_send_na(sc);
1167 #endif
1168 		carp_setrun(sc, 0);
1169 		carp_addroute(sc);
1170 		break;
1171 	case INIT:
1172 	case MASTER:
1173 #ifdef INVARIANTS
1174 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1175 		    sc->sc_vhid,
1176 		    sc->sc_carpdev->if_xname,
1177 		    sc->sc_state ? "MASTER" : "INIT");
1178 #endif
1179 		break;
1180 	}
1181 }
1182 
1183 /*
1184  * When in backup state, af indicates whether to reset the master down timer
1185  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1186  */
1187 static void
1188 carp_setrun(struct carp_softc *sc, sa_family_t af)
1189 {
1190 	struct timeval tv;
1191 
1192 	CARP_LOCK_ASSERT(sc);
1193 
1194 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1195 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1196 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0))
1197 		return;
1198 
1199 	switch (sc->sc_state) {
1200 	case INIT:
1201 		carp_set_state(sc, BACKUP, "initialization complete");
1202 		carp_setrun(sc, 0);
1203 		break;
1204 	case BACKUP:
1205 		callout_stop(&sc->sc_ad_tmo);
1206 		tv.tv_sec = 3 * sc->sc_advbase;
1207 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1208 		switch (af) {
1209 #ifdef INET
1210 		case AF_INET:
1211 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1212 			    carp_master_down, sc);
1213 			break;
1214 #endif
1215 #ifdef INET6
1216 		case AF_INET6:
1217 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1218 			    carp_master_down, sc);
1219 			break;
1220 #endif
1221 		default:
1222 #ifdef INET
1223 			if (sc->sc_naddrs)
1224 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1225 				    carp_master_down, sc);
1226 #endif
1227 #ifdef INET6
1228 			if (sc->sc_naddrs6)
1229 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1230 				    carp_master_down, sc);
1231 #endif
1232 			break;
1233 		}
1234 		break;
1235 	case MASTER:
1236 		tv.tv_sec = sc->sc_advbase;
1237 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1238 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1239 		    carp_send_ad, sc);
1240 		break;
1241 	}
1242 }
1243 
1244 /*
1245  * Setup multicast structures.
1246  */
1247 static int
1248 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1249 {
1250 	struct ifnet *ifp = cif->cif_ifp;
1251 	int error = 0;
1252 
1253 	CIF_LOCK_ASSERT(cif);
1254 
1255 	switch (sa) {
1256 #ifdef INET
1257 	case AF_INET:
1258 	    {
1259 		struct ip_moptions *imo = &cif->cif_imo;
1260 		struct in_addr addr;
1261 
1262 		if (imo->imo_membership)
1263 			return (0);
1264 
1265 		imo->imo_membership = (struct in_multi **)malloc(
1266 		    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
1267 		    M_NOWAIT);
1268 		if (imo->imo_membership == NULL)
1269 			return (ENOMEM);
1270 		imo->imo_mfilters = NULL;
1271 		imo->imo_max_memberships = IP_MIN_MEMBERSHIPS;
1272 		imo->imo_multicast_vif = -1;
1273 
1274 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1275 		if ((error = in_joingroup(ifp, &addr, NULL,
1276 		    &imo->imo_membership[0])) != 0) {
1277 			free(imo->imo_membership, M_CARP);
1278 			break;
1279 		}
1280 		imo->imo_num_memberships++;
1281 		imo->imo_multicast_ifp = ifp;
1282 		imo->imo_multicast_ttl = CARP_DFLTTL;
1283 		imo->imo_multicast_loop = 0;
1284 		break;
1285 	   }
1286 #endif
1287 #ifdef INET6
1288 	case AF_INET6:
1289 	    {
1290 		struct ip6_moptions *im6o = &cif->cif_im6o;
1291 		struct in6_addr in6;
1292 		struct in6_multi *in6m;
1293 
1294 		if (im6o->im6o_membership)
1295 			return (0);
1296 
1297 		im6o->im6o_membership = (struct in6_multi **)malloc(
1298 		    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
1299 		    M_ZERO | M_NOWAIT);
1300 		if (im6o->im6o_membership == NULL)
1301 			return (ENOMEM);
1302 		im6o->im6o_mfilters = NULL;
1303 		im6o->im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
1304 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1305 		im6o->im6o_multicast_ifp = ifp;
1306 
1307 		/* Join IPv6 CARP multicast group. */
1308 		bzero(&in6, sizeof(in6));
1309 		in6.s6_addr16[0] = htons(0xff02);
1310 		in6.s6_addr8[15] = 0x12;
1311 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1312 			free(im6o->im6o_membership, M_CARP);
1313 			break;
1314 		}
1315 		in6m = NULL;
1316 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1317 			free(im6o->im6o_membership, M_CARP);
1318 			break;
1319 		}
1320 		im6o->im6o_membership[0] = in6m;
1321 		im6o->im6o_num_memberships++;
1322 
1323 		/* Join solicited multicast address. */
1324 		bzero(&in6, sizeof(in6));
1325 		in6.s6_addr16[0] = htons(0xff02);
1326 		in6.s6_addr32[1] = 0;
1327 		in6.s6_addr32[2] = htonl(1);
1328 		in6.s6_addr32[3] = 0;
1329 		in6.s6_addr8[12] = 0xff;
1330 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1331 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1332 			free(im6o->im6o_membership, M_CARP);
1333 			break;
1334 		}
1335 		in6m = NULL;
1336 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1337 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1338 			free(im6o->im6o_membership, M_CARP);
1339 			break;
1340 		}
1341 		im6o->im6o_membership[1] = in6m;
1342 		im6o->im6o_num_memberships++;
1343 		break;
1344 	    }
1345 #endif
1346 	}
1347 
1348 	return (error);
1349 }
1350 
1351 /*
1352  * Free multicast structures.
1353  */
1354 static void
1355 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1356 {
1357 
1358 	CIF_LOCK_ASSERT(cif);
1359 	switch (sa) {
1360 #ifdef INET
1361 	case AF_INET:
1362 		if (cif->cif_naddrs == 0) {
1363 			struct ip_moptions *imo = &cif->cif_imo;
1364 
1365 			in_leavegroup(imo->imo_membership[0], NULL);
1366 			KASSERT(imo->imo_mfilters == NULL,
1367 			    ("%s: imo_mfilters != NULL", __func__));
1368 			free(imo->imo_membership, M_CARP);
1369 			imo->imo_membership = NULL;
1370 
1371 		}
1372 		break;
1373 #endif
1374 #ifdef INET6
1375 	case AF_INET6:
1376 		if (cif->cif_naddrs6 == 0) {
1377 			struct ip6_moptions *im6o = &cif->cif_im6o;
1378 
1379 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1380 			in6_mc_leave(im6o->im6o_membership[1], NULL);
1381 			KASSERT(im6o->im6o_mfilters == NULL,
1382 			    ("%s: im6o_mfilters != NULL", __func__));
1383 			free(im6o->im6o_membership, M_CARP);
1384 			im6o->im6o_membership = NULL;
1385 		}
1386 		break;
1387 #endif
1388 	}
1389 }
1390 
1391 int
1392 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1393 {
1394 	struct m_tag *mtag;
1395 	struct carp_softc *sc;
1396 
1397 	if (!sa)
1398 		return (0);
1399 
1400 	switch (sa->sa_family) {
1401 #ifdef INET
1402 	case AF_INET:
1403 		break;
1404 #endif
1405 #ifdef INET6
1406 	case AF_INET6:
1407 		break;
1408 #endif
1409 	default:
1410 		return (0);
1411 	}
1412 
1413 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1414 	if (mtag == NULL)
1415 		return (0);
1416 
1417 	bcopy(mtag + 1, &sc, sizeof(sc));
1418 
1419 	/* Set the source MAC address to the Virtual Router MAC Address. */
1420 	switch (ifp->if_type) {
1421 	case IFT_ETHER:
1422 	case IFT_BRIDGE:
1423 	case IFT_L2VLAN: {
1424 			struct ether_header *eh;
1425 
1426 			eh = mtod(m, struct ether_header *);
1427 			eh->ether_shost[0] = 0;
1428 			eh->ether_shost[1] = 0;
1429 			eh->ether_shost[2] = 0x5e;
1430 			eh->ether_shost[3] = 0;
1431 			eh->ether_shost[4] = 1;
1432 			eh->ether_shost[5] = sc->sc_vhid;
1433 		}
1434 		break;
1435 	case IFT_FDDI: {
1436 			struct fddi_header *fh;
1437 
1438 			fh = mtod(m, struct fddi_header *);
1439 			fh->fddi_shost[0] = 0;
1440 			fh->fddi_shost[1] = 0;
1441 			fh->fddi_shost[2] = 0x5e;
1442 			fh->fddi_shost[3] = 0;
1443 			fh->fddi_shost[4] = 1;
1444 			fh->fddi_shost[5] = sc->sc_vhid;
1445 		}
1446 		break;
1447 	case IFT_ISO88025: {
1448  			struct iso88025_header *th;
1449  			th = mtod(m, struct iso88025_header *);
1450 			th->iso88025_shost[0] = 3;
1451 			th->iso88025_shost[1] = 0;
1452 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
1453 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
1454 			th->iso88025_shost[4] = 0;
1455 			th->iso88025_shost[5] = 0;
1456 		}
1457 		break;
1458 	default:
1459 		printf("%s: carp is not supported for the %d interface type\n",
1460 		    ifp->if_xname, ifp->if_type);
1461 		return (EOPNOTSUPP);
1462 	}
1463 
1464 	return (0);
1465 }
1466 
1467 static struct carp_softc*
1468 carp_alloc(struct ifnet *ifp)
1469 {
1470 	struct carp_softc *sc;
1471 	struct carp_if *cif;
1472 
1473 	if ((cif = ifp->if_carp) == NULL)
1474 		cif = carp_alloc_if(ifp);
1475 
1476 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1477 
1478 	sc->sc_advbase = CARP_DFLTINTV;
1479 	sc->sc_vhid = -1;	/* required setting */
1480 	sc->sc_init_counter = 1;
1481 	sc->sc_state = INIT;
1482 
1483 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1484 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1485 	sc->sc_carpdev = ifp;
1486 
1487 	CARP_LOCK_INIT(sc);
1488 #ifdef INET
1489 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1490 #endif
1491 #ifdef INET6
1492 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1493 #endif
1494 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1495 
1496 	CIF_LOCK(cif);
1497 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1498 	CIF_UNLOCK(cif);
1499 
1500 	mtx_lock(&carp_mtx);
1501 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1502 	mtx_unlock(&carp_mtx);
1503 
1504 	return (sc);
1505 }
1506 
1507 static int
1508 carp_grow_ifas(struct carp_softc *sc)
1509 {
1510 	struct ifaddr **new;
1511 
1512 	CARP_LOCK_ASSERT(sc);
1513 
1514 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_NOWAIT|M_ZERO);
1515 	if (new == NULL)
1516 		return (ENOMEM);
1517 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1518 	free(sc->sc_ifas, M_CARP);
1519 	sc->sc_ifas = new;
1520 	sc->sc_ifasiz *= 2;
1521 
1522 	return (0);
1523 }
1524 
1525 static void
1526 carp_destroy(struct carp_softc *sc)
1527 {
1528 	struct ifnet *ifp = sc->sc_carpdev;
1529 	struct carp_if *cif = ifp->if_carp;
1530 
1531 	CIF_LOCK_ASSERT(cif);
1532 
1533 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1534 
1535 	mtx_lock(&carp_mtx);
1536 	LIST_REMOVE(sc, sc_next);
1537 	mtx_unlock(&carp_mtx);
1538 
1539 	CARP_LOCK(sc);
1540 	if (sc->sc_suppress)
1541 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1542 	callout_drain(&sc->sc_ad_tmo);
1543 #ifdef INET
1544 	callout_drain(&sc->sc_md_tmo);
1545 #endif
1546 #ifdef INET6
1547 	callout_drain(&sc->sc_md6_tmo);
1548 #endif
1549 	CARP_LOCK_DESTROY(sc);
1550 
1551 	free(sc->sc_ifas, M_CARP);
1552 	free(sc, M_CARP);
1553 }
1554 
1555 static struct carp_if*
1556 carp_alloc_if(struct ifnet *ifp)
1557 {
1558 	struct carp_if *cif;
1559 	int error;
1560 
1561 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1562 
1563 	if ((error = ifpromisc(ifp, 1)) != 0)
1564 		printf("%s: ifpromisc(%s) failed: %d\n",
1565 		    __func__, ifp->if_xname, error);
1566 	else
1567 		cif->cif_flags |= CIF_PROMISC;
1568 
1569 	CIF_LOCK_INIT(cif);
1570 	cif->cif_ifp = ifp;
1571 	TAILQ_INIT(&cif->cif_vrs);
1572 
1573 	IF_ADDR_WLOCK(ifp);
1574 	ifp->if_carp = cif;
1575 	if_ref(ifp);
1576 	IF_ADDR_WUNLOCK(ifp);
1577 
1578 	return (cif);
1579 }
1580 
1581 static void
1582 carp_free_if(struct carp_if *cif)
1583 {
1584 	struct ifnet *ifp = cif->cif_ifp;
1585 
1586 	CIF_LOCK_ASSERT(cif);
1587 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1588 	    __func__));
1589 
1590 	IF_ADDR_WLOCK(ifp);
1591 	ifp->if_carp = NULL;
1592 	IF_ADDR_WUNLOCK(ifp);
1593 
1594 	CIF_LOCK_DESTROY(cif);
1595 
1596 	if (cif->cif_flags & CIF_PROMISC)
1597 		ifpromisc(ifp, 0);
1598 	if_rele(ifp);
1599 
1600 	free(cif, M_CARP);
1601 }
1602 
1603 static void
1604 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1605 {
1606 
1607 	CARP_LOCK(sc);
1608 	carpr->carpr_state = sc->sc_state;
1609 	carpr->carpr_vhid = sc->sc_vhid;
1610 	carpr->carpr_advbase = sc->sc_advbase;
1611 	carpr->carpr_advskew = sc->sc_advskew;
1612 	if (priv)
1613 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1614 	else
1615 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1616 	CARP_UNLOCK(sc);
1617 }
1618 
1619 int
1620 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1621 {
1622 	struct carpreq carpr;
1623 	struct ifnet *ifp;
1624 	struct carp_softc *sc = NULL;
1625 	int error = 0, locked = 0;
1626 
1627 	if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1628 		return (error);
1629 
1630 	ifp = ifunit_ref(ifr->ifr_name);
1631 	if (ifp == NULL)
1632 		return (ENXIO);
1633 
1634 	switch (ifp->if_type) {
1635 	case IFT_ETHER:
1636 	case IFT_L2VLAN:
1637 	case IFT_BRIDGE:
1638 	case IFT_FDDI:
1639 	case IFT_ISO88025:
1640 		break;
1641 	default:
1642 		error = EOPNOTSUPP;
1643 		goto out;
1644 	}
1645 
1646 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1647 		error = EADDRNOTAVAIL;
1648 		goto out;
1649 	}
1650 
1651 	sx_xlock(&carp_sx);
1652 	switch (cmd) {
1653 	case SIOCSVH:
1654 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1655 			break;
1656 		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1657 		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1658 			error = EINVAL;
1659 			break;
1660 		}
1661 
1662 		if (ifp->if_carp) {
1663 			CIF_LOCK(ifp->if_carp);
1664 			IFNET_FOREACH_CARP(ifp, sc)
1665 				if (sc->sc_vhid == carpr.carpr_vhid)
1666 					break;
1667 			CIF_UNLOCK(ifp->if_carp);
1668 		}
1669 		if (sc == NULL) {
1670 			sc = carp_alloc(ifp);
1671 			CARP_LOCK(sc);
1672 			sc->sc_vhid = carpr.carpr_vhid;
1673 			LLADDR(&sc->sc_addr)[0] = 0;
1674 			LLADDR(&sc->sc_addr)[1] = 0;
1675 			LLADDR(&sc->sc_addr)[2] = 0x5e;
1676 			LLADDR(&sc->sc_addr)[3] = 0;
1677 			LLADDR(&sc->sc_addr)[4] = 1;
1678 			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1679 		} else
1680 			CARP_LOCK(sc);
1681 		locked = 1;
1682 		if (carpr.carpr_advbase > 0) {
1683 			if (carpr.carpr_advbase > 255 ||
1684 			    carpr.carpr_advbase < CARP_DFLTINTV) {
1685 				error = EINVAL;
1686 				break;
1687 			}
1688 			sc->sc_advbase = carpr.carpr_advbase;
1689 		}
1690 		if (carpr.carpr_advskew >= 255) {
1691 			error = EINVAL;
1692 			break;
1693 		}
1694 		sc->sc_advskew = carpr.carpr_advskew;
1695 		if (carpr.carpr_key[0] != '\0') {
1696 			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1697 			carp_hmac_prepare(sc);
1698 		}
1699 		if (sc->sc_state != INIT &&
1700 		    carpr.carpr_state != sc->sc_state) {
1701 			switch (carpr.carpr_state) {
1702 			case BACKUP:
1703 				callout_stop(&sc->sc_ad_tmo);
1704 				carp_set_state(sc, BACKUP,
1705 				    "user requested via ifconfig");
1706 				carp_setrun(sc, 0);
1707 				carp_delroute(sc);
1708 				break;
1709 			case MASTER:
1710 				carp_master_down_locked(sc,
1711 				    "user requested via ifconfig");
1712 				break;
1713 			default:
1714 				break;
1715 			}
1716 		}
1717 		break;
1718 
1719 	case SIOCGVH:
1720 	    {
1721 		int priveleged;
1722 
1723 		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1724 			error = EINVAL;
1725 			break;
1726 		}
1727 		if (carpr.carpr_count < 1) {
1728 			error = EMSGSIZE;
1729 			break;
1730 		}
1731 		if (ifp->if_carp == NULL) {
1732 			error = ENOENT;
1733 			break;
1734 		}
1735 
1736 		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1737 		if (carpr.carpr_vhid != 0) {
1738 			CIF_LOCK(ifp->if_carp);
1739 			IFNET_FOREACH_CARP(ifp, sc)
1740 				if (sc->sc_vhid == carpr.carpr_vhid)
1741 					break;
1742 			CIF_UNLOCK(ifp->if_carp);
1743 			if (sc == NULL) {
1744 				error = ENOENT;
1745 				break;
1746 			}
1747 			carp_carprcp(&carpr, sc, priveleged);
1748 			error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
1749 		} else  {
1750 			int i, count;
1751 
1752 			count = 0;
1753 			CIF_LOCK(ifp->if_carp);
1754 			IFNET_FOREACH_CARP(ifp, sc)
1755 				count++;
1756 
1757 			if (count > carpr.carpr_count) {
1758 				CIF_UNLOCK(ifp->if_carp);
1759 				error = EMSGSIZE;
1760 				break;
1761 			}
1762 
1763 			i = 0;
1764 			IFNET_FOREACH_CARP(ifp, sc) {
1765 				carp_carprcp(&carpr, sc, priveleged);
1766 				carpr.carpr_count = count;
1767 				error = copyout(&carpr, ifr->ifr_data +
1768 				    (i * sizeof(carpr)), sizeof(carpr));
1769 				if (error) {
1770 					CIF_UNLOCK(ifp->if_carp);
1771 					break;
1772 				}
1773 				i++;
1774 			}
1775 			CIF_UNLOCK(ifp->if_carp);
1776 		}
1777 		break;
1778 	    }
1779 	default:
1780 		error = EINVAL;
1781 	}
1782 	sx_xunlock(&carp_sx);
1783 
1784 out:
1785 	if (locked)
1786 		CARP_UNLOCK(sc);
1787 	if_rele(ifp);
1788 
1789 	return (error);
1790 }
1791 
1792 static int
1793 carp_get_vhid(struct ifaddr *ifa)
1794 {
1795 
1796 	if (ifa == NULL || ifa->ifa_carp == NULL)
1797 		return (0);
1798 
1799 	return (ifa->ifa_carp->sc_vhid);
1800 }
1801 
1802 int
1803 carp_attach(struct ifaddr *ifa, int vhid)
1804 {
1805 	struct ifnet *ifp = ifa->ifa_ifp;
1806 	struct carp_if *cif = ifp->if_carp;
1807 	struct carp_softc *sc;
1808 	int index, error;
1809 
1810 	if (ifp->if_carp == NULL)
1811 		return (ENOPROTOOPT);
1812 
1813 	switch (ifa->ifa_addr->sa_family) {
1814 #ifdef INET
1815 	case AF_INET:
1816 #endif
1817 #ifdef INET6
1818 	case AF_INET6:
1819 #endif
1820 		break;
1821 	default:
1822 		return (EPROTOTYPE);
1823 	}
1824 
1825 	CIF_LOCK(cif);
1826 	IFNET_FOREACH_CARP(ifp, sc)
1827 		if (sc->sc_vhid == vhid)
1828 			break;
1829 	if (sc == NULL) {
1830 		CIF_UNLOCK(cif);
1831 		return (ENOENT);
1832 	}
1833 
1834 	if (ifa->ifa_carp) {
1835 		if (ifa->ifa_carp->sc_vhid != vhid)
1836 			carp_detach_locked(ifa);
1837 		else {
1838 			CIF_UNLOCK(cif);
1839 			return (0);
1840 		}
1841 	}
1842 
1843 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1844 	if (error) {
1845 		CIF_FREE(cif);
1846 		return (error);
1847 	}
1848 
1849 	CARP_LOCK(sc);
1850 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1851 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1852 		if ((error = carp_grow_ifas(sc)) != 0) {
1853 			carp_multicast_cleanup(cif,
1854 			    ifa->ifa_addr->sa_family);
1855 			CARP_UNLOCK(sc);
1856 			CIF_FREE(cif);
1857 			return (error);
1858 		}
1859 
1860 	switch (ifa->ifa_addr->sa_family) {
1861 #ifdef INET
1862 	case AF_INET:
1863 		cif->cif_naddrs++;
1864 		sc->sc_naddrs++;
1865 		break;
1866 #endif
1867 #ifdef INET6
1868 	case AF_INET6:
1869 		cif->cif_naddrs6++;
1870 		sc->sc_naddrs6++;
1871 		break;
1872 #endif
1873 	}
1874 
1875 	ifa_ref(ifa);
1876 	sc->sc_ifas[index - 1] = ifa;
1877 	ifa->ifa_carp = sc;
1878 
1879 	carp_hmac_prepare(sc);
1880 	carp_sc_state(sc);
1881 
1882 	CARP_UNLOCK(sc);
1883 	CIF_UNLOCK(cif);
1884 
1885 	return (0);
1886 }
1887 
1888 void
1889 carp_detach(struct ifaddr *ifa)
1890 {
1891 	struct ifnet *ifp = ifa->ifa_ifp;
1892 	struct carp_if *cif = ifp->if_carp;
1893 
1894 	CIF_LOCK(cif);
1895 	carp_detach_locked(ifa);
1896 	CIF_FREE(cif);
1897 }
1898 
1899 static void
1900 carp_detach_locked(struct ifaddr *ifa)
1901 {
1902 	struct ifnet *ifp = ifa->ifa_ifp;
1903 	struct carp_if *cif = ifp->if_carp;
1904 	struct carp_softc *sc = ifa->ifa_carp;
1905 	int i, index;
1906 
1907 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1908 
1909 	CIF_LOCK_ASSERT(cif);
1910 	CARP_LOCK(sc);
1911 
1912 	/* Shift array. */
1913 	index = sc->sc_naddrs + sc->sc_naddrs6;
1914 	for (i = 0; i < index; i++)
1915 		if (sc->sc_ifas[i] == ifa)
1916 			break;
1917 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1918 	for (; i < index - 1; i++)
1919 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1920 	sc->sc_ifas[index - 1] = NULL;
1921 
1922 	switch (ifa->ifa_addr->sa_family) {
1923 #ifdef INET
1924 	case AF_INET:
1925 		cif->cif_naddrs--;
1926 		sc->sc_naddrs--;
1927 		break;
1928 #endif
1929 #ifdef INET6
1930 	case AF_INET6:
1931 		cif->cif_naddrs6--;
1932 		sc->sc_naddrs6--;
1933 		break;
1934 #endif
1935 	}
1936 
1937 	carp_ifa_delroute(ifa);
1938 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
1939 
1940 	ifa->ifa_carp = NULL;
1941 	ifa_free(ifa);
1942 
1943 	carp_hmac_prepare(sc);
1944 	carp_sc_state(sc);
1945 
1946 	if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) {
1947 		CARP_UNLOCK(sc);
1948 		carp_destroy(sc);
1949 	} else
1950 		CARP_UNLOCK(sc);
1951 }
1952 
1953 static void
1954 carp_set_state(struct carp_softc *sc, int state, const char *reason)
1955 {
1956 
1957 	CARP_LOCK_ASSERT(sc);
1958 
1959 	if (sc->sc_state != state) {
1960 		const char *carp_states[] = { CARP_STATES };
1961 		char subsys[IFNAMSIZ+5];
1962 
1963 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
1964 		    sc->sc_carpdev->if_xname);
1965 
1966 		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
1967 		    carp_states[sc->sc_state], carp_states[state], reason);
1968 
1969 		sc->sc_state = state;
1970 
1971 		devctl_notify("CARP", subsys, carp_states[state], NULL);
1972 	}
1973 }
1974 
1975 static void
1976 carp_linkstate(struct ifnet *ifp)
1977 {
1978 	struct carp_softc *sc;
1979 
1980 	CIF_LOCK(ifp->if_carp);
1981 	IFNET_FOREACH_CARP(ifp, sc) {
1982 		CARP_LOCK(sc);
1983 		carp_sc_state(sc);
1984 		CARP_UNLOCK(sc);
1985 	}
1986 	CIF_UNLOCK(ifp->if_carp);
1987 }
1988 
1989 static void
1990 carp_sc_state(struct carp_softc *sc)
1991 {
1992 
1993 	CARP_LOCK_ASSERT(sc);
1994 
1995 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1996 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
1997 		callout_stop(&sc->sc_ad_tmo);
1998 #ifdef INET
1999 		callout_stop(&sc->sc_md_tmo);
2000 #endif
2001 #ifdef INET6
2002 		callout_stop(&sc->sc_md6_tmo);
2003 #endif
2004 		carp_set_state(sc, INIT, "hardware interface down");
2005 		carp_setrun(sc, 0);
2006 		if (!sc->sc_suppress)
2007 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2008 		sc->sc_suppress = 1;
2009 	} else {
2010 		carp_set_state(sc, INIT, "hardware interface up");
2011 		carp_setrun(sc, 0);
2012 		if (sc->sc_suppress)
2013 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2014 		sc->sc_suppress = 0;
2015 	}
2016 }
2017 
2018 static void
2019 carp_demote_adj(int adj, char *reason)
2020 {
2021 	atomic_add_int(&V_carp_demotion, adj);
2022 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2023 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2024 }
2025 
2026 static int
2027 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2028 {
2029 	int new, error;
2030 
2031 	new = V_carp_demotion;
2032 	error = sysctl_handle_int(oidp, &new, 0, req);
2033 	if (error || !req->newptr)
2034 		return (error);
2035 
2036 	carp_demote_adj(new, "sysctl");
2037 
2038 	return (0);
2039 }
2040 
2041 #ifdef INET
2042 extern  struct domain inetdomain;
2043 static struct protosw in_carp_protosw = {
2044 	.pr_type =		SOCK_RAW,
2045 	.pr_domain =		&inetdomain,
2046 	.pr_protocol =		IPPROTO_CARP,
2047 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2048 	.pr_input =		carp_input,
2049 	.pr_output =		rip_output,
2050 	.pr_ctloutput =		rip_ctloutput,
2051 	.pr_usrreqs =		&rip_usrreqs
2052 };
2053 #endif
2054 
2055 #ifdef INET6
2056 extern	struct domain inet6domain;
2057 static struct protosw in6_carp_protosw = {
2058 	.pr_type =		SOCK_RAW,
2059 	.pr_domain =		&inet6domain,
2060 	.pr_protocol =		IPPROTO_CARP,
2061 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2062 	.pr_input =		carp6_input,
2063 	.pr_output =		rip6_output,
2064 	.pr_ctloutput =		rip6_ctloutput,
2065 	.pr_usrreqs =		&rip6_usrreqs
2066 };
2067 #endif
2068 
2069 static void
2070 carp_mod_cleanup(void)
2071 {
2072 
2073 #ifdef INET
2074 	if (proto_reg[CARP_INET] == 0) {
2075 		(void)ipproto_unregister(IPPROTO_CARP);
2076 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2077 		proto_reg[CARP_INET] = -1;
2078 	}
2079 	carp_iamatch_p = NULL;
2080 #endif
2081 #ifdef INET6
2082 	if (proto_reg[CARP_INET6] == 0) {
2083 		(void)ip6proto_unregister(IPPROTO_CARP);
2084 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2085 		proto_reg[CARP_INET6] = -1;
2086 	}
2087 	carp_iamatch6_p = NULL;
2088 	carp_macmatch6_p = NULL;
2089 #endif
2090 	carp_ioctl_p = NULL;
2091 	carp_attach_p = NULL;
2092 	carp_detach_p = NULL;
2093 	carp_get_vhid_p = NULL;
2094 	carp_linkstate_p = NULL;
2095 	carp_forus_p = NULL;
2096 	carp_output_p = NULL;
2097 	carp_demote_adj_p = NULL;
2098 	carp_master_p = NULL;
2099 	mtx_unlock(&carp_mtx);
2100 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2101 	mtx_destroy(&carp_mtx);
2102 	sx_destroy(&carp_sx);
2103 }
2104 
2105 static int
2106 carp_mod_load(void)
2107 {
2108 	int err;
2109 
2110 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2111 	sx_init(&carp_sx, "carp_sx");
2112 	LIST_INIT(&carp_list);
2113 	carp_get_vhid_p = carp_get_vhid;
2114 	carp_forus_p = carp_forus;
2115 	carp_output_p = carp_output;
2116 	carp_linkstate_p = carp_linkstate;
2117 	carp_ioctl_p = carp_ioctl;
2118 	carp_attach_p = carp_attach;
2119 	carp_detach_p = carp_detach;
2120 	carp_demote_adj_p = carp_demote_adj;
2121 	carp_master_p = carp_master;
2122 #ifdef INET6
2123 	carp_iamatch6_p = carp_iamatch6;
2124 	carp_macmatch6_p = carp_macmatch6;
2125 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2126 	    (struct protosw *)&in6_carp_protosw);
2127 	if (proto_reg[CARP_INET6]) {
2128 		printf("carp: error %d attaching to PF_INET6\n",
2129 		    proto_reg[CARP_INET6]);
2130 		carp_mod_cleanup();
2131 		return (proto_reg[CARP_INET6]);
2132 	}
2133 	err = ip6proto_register(IPPROTO_CARP);
2134 	if (err) {
2135 		printf("carp: error %d registering with INET6\n", err);
2136 		carp_mod_cleanup();
2137 		return (err);
2138 	}
2139 #endif
2140 #ifdef INET
2141 	carp_iamatch_p = carp_iamatch;
2142 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2143 	if (proto_reg[CARP_INET]) {
2144 		printf("carp: error %d attaching to PF_INET\n",
2145 		    proto_reg[CARP_INET]);
2146 		carp_mod_cleanup();
2147 		return (proto_reg[CARP_INET]);
2148 	}
2149 	err = ipproto_register(IPPROTO_CARP);
2150 	if (err) {
2151 		printf("carp: error %d registering with INET\n", err);
2152 		carp_mod_cleanup();
2153 		return (err);
2154 	}
2155 #endif
2156 	return (0);
2157 }
2158 
2159 static int
2160 carp_modevent(module_t mod, int type, void *data)
2161 {
2162 	switch (type) {
2163 	case MOD_LOAD:
2164 		return carp_mod_load();
2165 		/* NOTREACHED */
2166 	case MOD_UNLOAD:
2167 		mtx_lock(&carp_mtx);
2168 		if (LIST_EMPTY(&carp_list))
2169 			carp_mod_cleanup();
2170 		else {
2171 			mtx_unlock(&carp_mtx);
2172 			return (EBUSY);
2173 		}
2174 		break;
2175 
2176 	default:
2177 		return (EINVAL);
2178 	}
2179 
2180 	return (0);
2181 }
2182 
2183 static moduledata_t carp_mod = {
2184 	"carp",
2185 	carp_modevent,
2186 	0
2187 };
2188 
2189 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2190