xref: /freebsd/sys/netinet/ip_carp.c (revision a812392203d7c4c3f0db9d8a0f3391374c49c71f)
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  * - There is no protection for races between two ioctl() requests,
184  *   neither SIOCSVH, nor SIOCAIFADDR & SIOCAIFADDR_IN6. I think that all
185  *   interface ioctl()s should be serialized right in net/if.c.
186  * - Sending ad, we put the pointer to the softc in an mtag, and no reference
187  *   counting is done on the softc.
188  * - On module unload we may race (?) with packet processing thread
189  *   dereferencing our function pointers.
190  */
191 
192 /* Accept incoming CARP packets. */
193 static VNET_DEFINE(int, carp_allow) = 1;
194 #define	V_carp_allow	VNET(carp_allow)
195 
196 /* Preempt slower nodes. */
197 static VNET_DEFINE(int, carp_preempt) = 0;
198 #define	V_carp_preempt	VNET(carp_preempt)
199 
200 /* Log level. */
201 static VNET_DEFINE(int, carp_log) = 1;
202 #define	V_carp_log	VNET(carp_log)
203 
204 /* Global advskew demotion. */
205 static VNET_DEFINE(int, carp_demotion) = 0;
206 #define	V_carp_demotion	VNET(carp_demotion)
207 
208 /* Send error demotion factor. */
209 static VNET_DEFINE(int, carp_senderr_adj) = CARP_MAXSKEW;
210 #define	V_carp_senderr_adj	VNET(carp_senderr_adj)
211 
212 /* Iface down demotion factor. */
213 static VNET_DEFINE(int, carp_ifdown_adj) = CARP_MAXSKEW;
214 #define	V_carp_ifdown_adj	VNET(carp_ifdown_adj)
215 
216 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
217 
218 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
219 SYSCTL_INT(_net_inet_carp, OID_AUTO, allow, CTLFLAG_VNET | CTLFLAG_RW,
220     &VNET_NAME(carp_allow), 0, "Accept incoming CARP packets");
221 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
222     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
223 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
224     &VNET_NAME(carp_log), 0, "CARP log level");
225 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
226     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW,
227     0, 0, carp_demote_adj_sysctl, "I",
228     "Adjust demotion factor (skew of advskew)");
229 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
230     CTLFLAG_VNET | CTLFLAG_RW,
231     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
232 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
233     CTLFLAG_VNET | CTLFLAG_RW,
234     &VNET_NAME(carp_ifdown_adj), 0,
235     "Interface down demotion factor adjustment");
236 
237 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
238 VNET_PCPUSTAT_SYSINIT(carpstats);
239 VNET_PCPUSTAT_SYSUNINIT(carpstats);
240 
241 #define	CARPSTATS_ADD(name, val)	\
242     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
243 	sizeof(uint64_t)], (val))
244 #define	CARPSTATS_INC(name)		CARPSTATS_ADD(name, 1)
245 
246 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
247     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
248 
249 #define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
250 	NULL, MTX_DEF)
251 #define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
252 #define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
253 #define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
254 #define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
255 #define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
256 	NULL, MTX_DEF)
257 #define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
258 #define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
259 #define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
260 #define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
261 #define	CIF_FREE(cif)	do {				\
262 		CIF_LOCK_ASSERT(cif);			\
263 		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
264 			carp_free_if(cif);		\
265 		else					\
266 			CIF_UNLOCK(cif);		\
267 } while (0)
268 
269 #define	CARP_LOG(...)	do {				\
270 	if (V_carp_log > 0)				\
271 		log(LOG_INFO, "carp: " __VA_ARGS__);	\
272 } while (0)
273 
274 #define	CARP_DEBUG(...)	do {				\
275 	if (V_carp_log > 1)				\
276 		log(LOG_DEBUG, __VA_ARGS__);		\
277 } while (0)
278 
279 #define	IFNET_FOREACH_IFA(ifp, ifa)					\
280 	IF_ADDR_LOCK_ASSERT(ifp);					\
281 	TAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)		\
282 		if ((ifa)->ifa_carp != NULL)
283 
284 #define	CARP_FOREACH_IFA(sc, ifa)					\
285 	CARP_LOCK_ASSERT(sc);						\
286 	for (int _i = 0;						\
287 		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
288 		((ifa) = sc->sc_ifas[_i]) != NULL;			\
289 		++_i)
290 
291 #define	IFNET_FOREACH_CARP(ifp, sc)					\
292 	CIF_LOCK_ASSERT(ifp->if_carp);					\
293 	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
294 
295 #define	DEMOTE_ADVSKEW(sc)					\
296     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?	\
297     CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion))
298 
299 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
300 static struct carp_softc
301 		*carp_alloc(struct ifnet *);
302 static void	carp_detach_locked(struct ifaddr *);
303 static void	carp_destroy(struct carp_softc *);
304 static struct carp_if
305 		*carp_alloc_if(struct ifnet *);
306 static void	carp_free_if(struct carp_if *);
307 static void	carp_set_state(struct carp_softc *, int);
308 static void	carp_sc_state(struct carp_softc *);
309 static void	carp_setrun(struct carp_softc *, sa_family_t);
310 static void	carp_master_down(void *);
311 static void	carp_master_down_locked(struct carp_softc *);
312 static void	carp_send_ad(void *);
313 static void	carp_send_ad_locked(struct carp_softc *);
314 static void	carp_addroute(struct carp_softc *);
315 static void	carp_ifa_addroute(struct ifaddr *);
316 static void	carp_delroute(struct carp_softc *);
317 static void	carp_ifa_delroute(struct ifaddr *);
318 static void	carp_send_ad_all(void *, int);
319 static void	carp_demote_adj(int, char *);
320 
321 static LIST_HEAD(, carp_softc) carp_list;
322 static struct mtx carp_mtx;
323 static struct task carp_sendall_task =
324     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
325 
326 static void
327 carp_hmac_prepare(struct carp_softc *sc)
328 {
329 	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
330 	uint8_t vhid = sc->sc_vhid & 0xff;
331 	struct ifaddr *ifa;
332 	int i, found;
333 #ifdef INET
334 	struct in_addr last, cur, in;
335 #endif
336 #ifdef INET6
337 	struct in6_addr last6, cur6, in6;
338 #endif
339 
340 	CARP_LOCK_ASSERT(sc);
341 
342 	/* Compute ipad from key. */
343 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
344 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
345 	for (i = 0; i < sizeof(sc->sc_pad); i++)
346 		sc->sc_pad[i] ^= 0x36;
347 
348 	/* Precompute first part of inner hash. */
349 	SHA1Init(&sc->sc_sha1);
350 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
351 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
352 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
353 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
354 #ifdef INET
355 	cur.s_addr = 0;
356 	do {
357 		found = 0;
358 		last = cur;
359 		cur.s_addr = 0xffffffff;
360 		CARP_FOREACH_IFA(sc, ifa) {
361 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
362 			if (ifa->ifa_addr->sa_family == AF_INET &&
363 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
364 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
365 				cur.s_addr = in.s_addr;
366 				found++;
367 			}
368 		}
369 		if (found)
370 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
371 	} while (found);
372 #endif /* INET */
373 #ifdef INET6
374 	memset(&cur6, 0, sizeof(cur6));
375 	do {
376 		found = 0;
377 		last6 = cur6;
378 		memset(&cur6, 0xff, sizeof(cur6));
379 		CARP_FOREACH_IFA(sc, ifa) {
380 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
381 			if (IN6_IS_SCOPE_EMBED(&in6))
382 				in6.s6_addr16[1] = 0;
383 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
384 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
385 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
386 				cur6 = in6;
387 				found++;
388 			}
389 		}
390 		if (found)
391 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
392 	} while (found);
393 #endif /* INET6 */
394 
395 	/* convert ipad to opad */
396 	for (i = 0; i < sizeof(sc->sc_pad); i++)
397 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
398 }
399 
400 static void
401 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
402     unsigned char md[20])
403 {
404 	SHA1_CTX sha1ctx;
405 
406 	CARP_LOCK_ASSERT(sc);
407 
408 	/* fetch first half of inner hash */
409 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
410 
411 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
412 	SHA1Final(md, &sha1ctx);
413 
414 	/* outer hash */
415 	SHA1Init(&sha1ctx);
416 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
417 	SHA1Update(&sha1ctx, md, 20);
418 	SHA1Final(md, &sha1ctx);
419 }
420 
421 static int
422 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
423     unsigned char md[20])
424 {
425 	unsigned char md2[20];
426 
427 	CARP_LOCK_ASSERT(sc);
428 
429 	carp_hmac_generate(sc, counter, md2);
430 
431 	return (bcmp(md, md2, sizeof(md2)));
432 }
433 
434 /*
435  * process input packet.
436  * we have rearranged checks order compared to the rfc,
437  * but it seems more efficient this way or not possible otherwise.
438  */
439 #ifdef INET
440 int
441 carp_input(struct mbuf **mp, int *offp, int proto)
442 {
443 	struct mbuf *m = *mp;
444 	struct ip *ip = mtod(m, struct ip *);
445 	struct carp_header *ch;
446 	int iplen, len;
447 
448 	iplen = *offp;
449 	*mp = NULL;
450 
451 	CARPSTATS_INC(carps_ipackets);
452 
453 	if (!V_carp_allow) {
454 		m_freem(m);
455 		return (IPPROTO_DONE);
456 	}
457 
458 	/* verify that the IP TTL is 255.  */
459 	if (ip->ip_ttl != CARP_DFLTTL) {
460 		CARPSTATS_INC(carps_badttl);
461 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
462 		    ip->ip_ttl,
463 		    m->m_pkthdr.rcvif->if_xname);
464 		m_freem(m);
465 		return (IPPROTO_DONE);
466 	}
467 
468 	iplen = ip->ip_hl << 2;
469 
470 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
471 		CARPSTATS_INC(carps_badlen);
472 		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
473 		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
474 		    m->m_pkthdr.rcvif->if_xname);
475 		m_freem(m);
476 		return (IPPROTO_DONE);
477 	}
478 
479 	if (iplen + sizeof(*ch) < m->m_len) {
480 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
481 			CARPSTATS_INC(carps_hdrops);
482 			CARP_DEBUG("%s: pullup failed\n", __func__);
483 			return (IPPROTO_DONE);
484 		}
485 		ip = mtod(m, struct ip *);
486 	}
487 	ch = (struct carp_header *)((char *)ip + iplen);
488 
489 	/*
490 	 * verify that the received packet length is
491 	 * equal to the CARP header
492 	 */
493 	len = iplen + sizeof(*ch);
494 	if (len > m->m_pkthdr.len) {
495 		CARPSTATS_INC(carps_badlen);
496 		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
497 		    m->m_pkthdr.len,
498 		    m->m_pkthdr.rcvif->if_xname);
499 		m_freem(m);
500 		return (IPPROTO_DONE);
501 	}
502 
503 	if ((m = m_pullup(m, len)) == NULL) {
504 		CARPSTATS_INC(carps_hdrops);
505 		return (IPPROTO_DONE);
506 	}
507 	ip = mtod(m, struct ip *);
508 	ch = (struct carp_header *)((char *)ip + iplen);
509 
510 	/* verify the CARP checksum */
511 	m->m_data += iplen;
512 	if (in_cksum(m, len - iplen)) {
513 		CARPSTATS_INC(carps_badsum);
514 		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
515 		    m->m_pkthdr.rcvif->if_xname);
516 		m_freem(m);
517 		return (IPPROTO_DONE);
518 	}
519 	m->m_data -= iplen;
520 
521 	carp_input_c(m, ch, AF_INET);
522 	return (IPPROTO_DONE);
523 }
524 #endif
525 
526 #ifdef INET6
527 int
528 carp6_input(struct mbuf **mp, int *offp, int proto)
529 {
530 	struct mbuf *m = *mp;
531 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
532 	struct carp_header *ch;
533 	u_int len;
534 
535 	CARPSTATS_INC(carps_ipackets6);
536 
537 	if (!V_carp_allow) {
538 		m_freem(m);
539 		return (IPPROTO_DONE);
540 	}
541 
542 	/* check if received on a valid carp interface */
543 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
544 		CARPSTATS_INC(carps_badif);
545 		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
546 		    __func__, m->m_pkthdr.rcvif->if_xname);
547 		m_freem(m);
548 		return (IPPROTO_DONE);
549 	}
550 
551 	/* verify that the IP TTL is 255 */
552 	if (ip6->ip6_hlim != CARP_DFLTTL) {
553 		CARPSTATS_INC(carps_badttl);
554 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
555 		    ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
556 		m_freem(m);
557 		return (IPPROTO_DONE);
558 	}
559 
560 	/* verify that we have a complete carp packet */
561 	len = m->m_len;
562 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
563 	if (ch == NULL) {
564 		CARPSTATS_INC(carps_badlen);
565 		CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
566 		return (IPPROTO_DONE);
567 	}
568 
569 
570 	/* verify the CARP checksum */
571 	m->m_data += *offp;
572 	if (in_cksum(m, sizeof(*ch))) {
573 		CARPSTATS_INC(carps_badsum);
574 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
575 		    m->m_pkthdr.rcvif->if_xname);
576 		m_freem(m);
577 		return (IPPROTO_DONE);
578 	}
579 	m->m_data -= *offp;
580 
581 	carp_input_c(m, ch, AF_INET6);
582 	return (IPPROTO_DONE);
583 }
584 #endif /* INET6 */
585 
586 static void
587 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
588 {
589 	struct ifnet *ifp = m->m_pkthdr.rcvif;
590 	struct ifaddr *ifa;
591 	struct carp_softc *sc;
592 	uint64_t tmp_counter;
593 	struct timeval sc_tv, ch_tv;
594 
595 	/* verify that the VHID is valid on the receiving interface */
596 	IF_ADDR_RLOCK(ifp);
597 	IFNET_FOREACH_IFA(ifp, ifa)
598 		if (ifa->ifa_addr->sa_family == af &&
599 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid) {
600 			ifa_ref(ifa);
601 			break;
602 		}
603 	IF_ADDR_RUNLOCK(ifp);
604 
605 	if (ifa == NULL) {
606 		CARPSTATS_INC(carps_badvhid);
607 		m_freem(m);
608 		return;
609 	}
610 
611 	/* verify the CARP version. */
612 	if (ch->carp_version != CARP_VERSION) {
613 		CARPSTATS_INC(carps_badver);
614 		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
615 		    ch->carp_version);
616 		ifa_free(ifa);
617 		m_freem(m);
618 		return;
619 	}
620 
621 	sc = ifa->ifa_carp;
622 	CARP_LOCK(sc);
623 	ifa_free(ifa);
624 
625 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
626 		CARPSTATS_INC(carps_badauth);
627 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
628 		    sc->sc_vhid, ifp->if_xname);
629 		goto out;
630 	}
631 
632 	tmp_counter = ntohl(ch->carp_counter[0]);
633 	tmp_counter = tmp_counter<<32;
634 	tmp_counter += ntohl(ch->carp_counter[1]);
635 
636 	/* XXX Replay protection goes here */
637 
638 	sc->sc_init_counter = 0;
639 	sc->sc_counter = tmp_counter;
640 
641 	sc_tv.tv_sec = sc->sc_advbase;
642 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
643 	ch_tv.tv_sec = ch->carp_advbase;
644 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
645 
646 	switch (sc->sc_state) {
647 	case INIT:
648 		break;
649 	case MASTER:
650 		/*
651 		 * If we receive an advertisement from a master who's going to
652 		 * be more frequent than us, go into BACKUP state.
653 		 */
654 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
655 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
656 			callout_stop(&sc->sc_ad_tmo);
657 			CARP_LOG("VHID %u@%s: MASTER -> BACKUP "
658 			    "(more frequent advertisement received)\n",
659 			    sc->sc_vhid,
660 			    sc->sc_carpdev->if_xname);
661 			carp_set_state(sc, BACKUP);
662 			carp_setrun(sc, 0);
663 			carp_delroute(sc);
664 		}
665 		break;
666 	case BACKUP:
667 		/*
668 		 * If we're pre-empting masters who advertise slower than us,
669 		 * and this one claims to be slower, treat him as down.
670 		 */
671 		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
672 			CARP_LOG("VHID %u@%s: BACKUP -> MASTER "
673 			    "(preempting a slower master)\n",
674 			    sc->sc_vhid,
675 			    sc->sc_carpdev->if_xname);
676 			carp_master_down_locked(sc);
677 			break;
678 		}
679 
680 		/*
681 		 *  If the master is going to advertise at such a low frequency
682 		 *  that he's guaranteed to time out, we'd might as well just
683 		 *  treat him as timed out now.
684 		 */
685 		sc_tv.tv_sec = sc->sc_advbase * 3;
686 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
687 			CARP_LOG("VHID %u@%s: BACKUP -> MASTER "
688 			    "(master timed out)\n",
689 			    sc->sc_vhid,
690 			    sc->sc_carpdev->if_xname);
691 			carp_master_down_locked(sc);
692 			break;
693 		}
694 
695 		/*
696 		 * Otherwise, we reset the counter and wait for the next
697 		 * advertisement.
698 		 */
699 		carp_setrun(sc, af);
700 		break;
701 	}
702 
703 out:
704 	CARP_UNLOCK(sc);
705 	m_freem(m);
706 }
707 
708 static int
709 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
710 {
711 	struct m_tag *mtag;
712 
713 	if (sc->sc_init_counter) {
714 		/* this could also be seconds since unix epoch */
715 		sc->sc_counter = arc4random();
716 		sc->sc_counter = sc->sc_counter << 32;
717 		sc->sc_counter += arc4random();
718 	} else
719 		sc->sc_counter++;
720 
721 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
722 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
723 
724 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
725 
726 	/* Tag packet for carp_output */
727 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
728 	    M_NOWAIT)) == NULL) {
729 		m_freem(m);
730 		CARPSTATS_INC(carps_onomem);
731 		return (ENOMEM);
732 	}
733 	bcopy(&sc, mtag + 1, sizeof(sc));
734 	m_tag_prepend(m, mtag);
735 
736 	return (0);
737 }
738 
739 /*
740  * To avoid LORs and possible recursions this function shouldn't
741  * be called directly, but scheduled via taskqueue.
742  */
743 static void
744 carp_send_ad_all(void *ctx __unused, int pending __unused)
745 {
746 	struct carp_softc *sc;
747 
748 	mtx_lock(&carp_mtx);
749 	LIST_FOREACH(sc, &carp_list, sc_next)
750 		if (sc->sc_state == MASTER) {
751 			CARP_LOCK(sc);
752 			CURVNET_SET(sc->sc_carpdev->if_vnet);
753 			carp_send_ad_locked(sc);
754 			CURVNET_RESTORE();
755 			CARP_UNLOCK(sc);
756 		}
757 	mtx_unlock(&carp_mtx);
758 }
759 
760 /* Send a periodic advertisement, executed in callout context. */
761 static void
762 carp_send_ad(void *v)
763 {
764 	struct carp_softc *sc = v;
765 
766 	CARP_LOCK_ASSERT(sc);
767 	CURVNET_SET(sc->sc_carpdev->if_vnet);
768 	carp_send_ad_locked(sc);
769 	CURVNET_RESTORE();
770 	CARP_UNLOCK(sc);
771 }
772 
773 static void
774 carp_send_ad_error(struct carp_softc *sc, int error)
775 {
776 
777 	if (error) {
778 		if (sc->sc_sendad_errors < INT_MAX)
779 			sc->sc_sendad_errors++;
780 		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
781 			static const char fmt[] = "send error %d on %s";
782 			char msg[sizeof(fmt) + IFNAMSIZ];
783 
784 			sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
785 			carp_demote_adj(V_carp_senderr_adj, msg);
786 		}
787 		sc->sc_sendad_success = 0;
788 	} else {
789 		if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
790 		    ++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
791 			static const char fmt[] = "send ok on %s";
792 			char msg[sizeof(fmt) + IFNAMSIZ];
793 
794 			sprintf(msg, fmt, sc->sc_carpdev->if_xname);
795 			carp_demote_adj(-V_carp_senderr_adj, msg);
796 			sc->sc_sendad_errors = 0;
797 		} else
798 			sc->sc_sendad_errors = 0;
799 	}
800 }
801 
802 static void
803 carp_send_ad_locked(struct carp_softc *sc)
804 {
805 	struct carp_header ch;
806 	struct timeval tv;
807 	struct sockaddr sa;
808 	struct ifaddr *ifa;
809 	struct carp_header *ch_ptr;
810 	struct mbuf *m;
811 	int len, advskew;
812 
813 	CARP_LOCK_ASSERT(sc);
814 
815 	advskew = DEMOTE_ADVSKEW(sc);
816 	tv.tv_sec = sc->sc_advbase;
817 	tv.tv_usec = advskew * 1000000 / 256;
818 
819 	ch.carp_version = CARP_VERSION;
820 	ch.carp_type = CARP_ADVERTISEMENT;
821 	ch.carp_vhid = sc->sc_vhid;
822 	ch.carp_advbase = sc->sc_advbase;
823 	ch.carp_advskew = advskew;
824 	ch.carp_authlen = 7;	/* XXX DEFINE */
825 	ch.carp_pad1 = 0;	/* must be zero */
826 	ch.carp_cksum = 0;
827 
828 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
829 
830 #ifdef INET
831 	if (sc->sc_naddrs) {
832 		struct ip *ip;
833 
834 		m = m_gethdr(M_NOWAIT, MT_DATA);
835 		if (m == NULL) {
836 			CARPSTATS_INC(carps_onomem);
837 			goto resched;
838 		}
839 		len = sizeof(*ip) + sizeof(ch);
840 		m->m_pkthdr.len = len;
841 		m->m_pkthdr.rcvif = NULL;
842 		m->m_len = len;
843 		MH_ALIGN(m, m->m_len);
844 		m->m_flags |= M_MCAST;
845 		ip = mtod(m, struct ip *);
846 		ip->ip_v = IPVERSION;
847 		ip->ip_hl = sizeof(*ip) >> 2;
848 		ip->ip_tos = IPTOS_LOWDELAY;
849 		ip->ip_len = htons(len);
850 		ip->ip_id = ip_newid();
851 		ip->ip_off = htons(IP_DF);
852 		ip->ip_ttl = CARP_DFLTTL;
853 		ip->ip_p = IPPROTO_CARP;
854 		ip->ip_sum = 0;
855 
856 		bzero(&sa, sizeof(sa));
857 		sa.sa_family = AF_INET;
858 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
859 		if (ifa != NULL) {
860 			ip->ip_src.s_addr =
861 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
862 			ifa_free(ifa);
863 		} else
864 			ip->ip_src.s_addr = 0;
865 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
866 
867 		ch_ptr = (struct carp_header *)(&ip[1]);
868 		bcopy(&ch, ch_ptr, sizeof(ch));
869 		if (carp_prepare_ad(m, sc, ch_ptr))
870 			goto resched;
871 
872 		m->m_data += sizeof(*ip);
873 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
874 		m->m_data -= sizeof(*ip);
875 
876 		CARPSTATS_INC(carps_opackets);
877 
878 		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
879 		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
880 	}
881 #endif /* INET */
882 #ifdef INET6
883 	if (sc->sc_naddrs6) {
884 		struct ip6_hdr *ip6;
885 
886 		m = m_gethdr(M_NOWAIT, MT_DATA);
887 		if (m == NULL) {
888 			CARPSTATS_INC(carps_onomem);
889 			goto resched;
890 		}
891 		len = sizeof(*ip6) + sizeof(ch);
892 		m->m_pkthdr.len = len;
893 		m->m_pkthdr.rcvif = NULL;
894 		m->m_len = len;
895 		MH_ALIGN(m, m->m_len);
896 		m->m_flags |= M_MCAST;
897 		ip6 = mtod(m, struct ip6_hdr *);
898 		bzero(ip6, sizeof(*ip6));
899 		ip6->ip6_vfc |= IPV6_VERSION;
900 		ip6->ip6_hlim = CARP_DFLTTL;
901 		ip6->ip6_nxt = IPPROTO_CARP;
902 		bzero(&sa, sizeof(sa));
903 
904 		/* set the source address */
905 		sa.sa_family = AF_INET6;
906 		ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
907 		if (ifa != NULL) {
908 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
909 			    sizeof(struct in6_addr));
910 			ifa_free(ifa);
911 		} else
912 			/* This should never happen with IPv6. */
913 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
914 
915 		/* Set the multicast destination. */
916 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
917 		ip6->ip6_dst.s6_addr8[15] = 0x12;
918 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
919 			m_freem(m);
920 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
921 			goto resched;
922 		}
923 
924 		ch_ptr = (struct carp_header *)(&ip6[1]);
925 		bcopy(&ch, ch_ptr, sizeof(ch));
926 		if (carp_prepare_ad(m, sc, ch_ptr))
927 			goto resched;
928 
929 		m->m_data += sizeof(*ip6);
930 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
931 		m->m_data -= sizeof(*ip6);
932 
933 		CARPSTATS_INC(carps_opackets6);
934 
935 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
936 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
937 	}
938 #endif /* INET6 */
939 
940 resched:
941 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
942 }
943 
944 static void
945 carp_addroute(struct carp_softc *sc)
946 {
947 	struct ifaddr *ifa;
948 
949 	CARP_FOREACH_IFA(sc, ifa)
950 		carp_ifa_addroute(ifa);
951 }
952 
953 static void
954 carp_ifa_addroute(struct ifaddr *ifa)
955 {
956 
957 	switch (ifa->ifa_addr->sa_family) {
958 #ifdef INET
959 	case AF_INET:
960 		in_addprefix(ifatoia(ifa), RTF_UP);
961 		ifa_add_loopback_route(ifa,
962 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
963 		break;
964 #endif
965 #ifdef INET6
966 	case AF_INET6:
967 		ifa_add_loopback_route(ifa,
968 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
969 		nd6_add_ifa_lle(ifatoia6(ifa));
970 		break;
971 #endif
972 	}
973 }
974 
975 static void
976 carp_delroute(struct carp_softc *sc)
977 {
978 	struct ifaddr *ifa;
979 
980 	CARP_FOREACH_IFA(sc, ifa)
981 		carp_ifa_delroute(ifa);
982 }
983 
984 static void
985 carp_ifa_delroute(struct ifaddr *ifa)
986 {
987 
988 	switch (ifa->ifa_addr->sa_family) {
989 #ifdef INET
990 	case AF_INET:
991 		ifa_del_loopback_route(ifa,
992 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
993 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
994 		break;
995 #endif
996 #ifdef INET6
997 	case AF_INET6:
998 		ifa_del_loopback_route(ifa,
999 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1000 		nd6_rem_ifa_lle(ifatoia6(ifa));
1001 		break;
1002 #endif
1003 	}
1004 }
1005 
1006 int
1007 carp_master(struct ifaddr *ifa)
1008 {
1009 	struct carp_softc *sc = ifa->ifa_carp;
1010 
1011 	return (sc->sc_state == MASTER);
1012 }
1013 
1014 #ifdef INET
1015 /*
1016  * Broadcast a gratuitous ARP request containing
1017  * the virtual router MAC address for each IP address
1018  * associated with the virtual router.
1019  */
1020 static void
1021 carp_send_arp(struct carp_softc *sc)
1022 {
1023 	struct ifaddr *ifa;
1024 
1025 	CARP_FOREACH_IFA(sc, ifa)
1026 		if (ifa->ifa_addr->sa_family == AF_INET)
1027 			arp_ifinit2(sc->sc_carpdev, ifa, LLADDR(&sc->sc_addr));
1028 }
1029 
1030 int
1031 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1032 {
1033 	struct carp_softc *sc = ifa->ifa_carp;
1034 
1035 	if (sc->sc_state == MASTER) {
1036 		*enaddr = LLADDR(&sc->sc_addr);
1037 		return (1);
1038 	}
1039 
1040 	return (0);
1041 }
1042 #endif
1043 
1044 #ifdef INET6
1045 static void
1046 carp_send_na(struct carp_softc *sc)
1047 {
1048 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1049 	struct ifaddr *ifa;
1050 	struct in6_addr *in6;
1051 
1052 	CARP_FOREACH_IFA(sc, ifa) {
1053 		if (ifa->ifa_addr->sa_family != AF_INET6)
1054 			continue;
1055 
1056 		in6 = IFA_IN6(ifa);
1057 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1058 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1059 		DELAY(1000);	/* XXX */
1060 	}
1061 }
1062 
1063 /*
1064  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1065  * matches and is not a carp address.  Returns NULL otherwise.
1066  */
1067 struct ifaddr *
1068 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1069 {
1070 	struct ifaddr *ifa;
1071 
1072 	ifa = NULL;
1073 	IF_ADDR_RLOCK(ifp);
1074 	TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1075 		if (ifa->ifa_addr->sa_family != AF_INET6)
1076 			continue;
1077 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1078 			continue;
1079 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1080 			ifa = NULL;
1081 		else
1082 			ifa_ref(ifa);
1083 		break;
1084 	}
1085 	IF_ADDR_RUNLOCK(ifp);
1086 
1087 	return (ifa);
1088 }
1089 
1090 caddr_t
1091 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1092 {
1093 	struct ifaddr *ifa;
1094 
1095 	IF_ADDR_RLOCK(ifp);
1096 	IFNET_FOREACH_IFA(ifp, ifa)
1097 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1098 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1099 			struct carp_softc *sc = ifa->ifa_carp;
1100 			struct m_tag *mtag;
1101 
1102 			IF_ADDR_RUNLOCK(ifp);
1103 
1104 			mtag = m_tag_get(PACKET_TAG_CARP,
1105 			    sizeof(struct carp_softc *), M_NOWAIT);
1106 			if (mtag == NULL)
1107 				/* Better a bit than nothing. */
1108 				return (LLADDR(&sc->sc_addr));
1109 
1110 			bcopy(&sc, mtag + 1, sizeof(sc));
1111 			m_tag_prepend(m, mtag);
1112 
1113 			return (LLADDR(&sc->sc_addr));
1114 		}
1115 	IF_ADDR_RUNLOCK(ifp);
1116 
1117 	return (NULL);
1118 }
1119 #endif /* INET6 */
1120 
1121 int
1122 carp_forus(struct ifnet *ifp, u_char *dhost)
1123 {
1124 	struct carp_softc *sc;
1125 	uint8_t *ena = dhost;
1126 
1127 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1128 		return (0);
1129 
1130 	CIF_LOCK(ifp->if_carp);
1131 	IFNET_FOREACH_CARP(ifp, sc) {
1132 		CARP_LOCK(sc);
1133 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1134 		    ETHER_ADDR_LEN)) {
1135 			CARP_UNLOCK(sc);
1136 			CIF_UNLOCK(ifp->if_carp);
1137 			return (1);
1138 		}
1139 		CARP_UNLOCK(sc);
1140 	}
1141 	CIF_UNLOCK(ifp->if_carp);
1142 
1143 	return (0);
1144 }
1145 
1146 /* Master down timeout event, executed in callout context. */
1147 static void
1148 carp_master_down(void *v)
1149 {
1150 	struct carp_softc *sc = v;
1151 
1152 	CARP_LOCK_ASSERT(sc);
1153 
1154 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1155 	if (sc->sc_state == BACKUP) {
1156 		CARP_LOG("VHID %u@%s: BACKUP -> MASTER (master down)\n",
1157 		    sc->sc_vhid,
1158 		    sc->sc_carpdev->if_xname);
1159 		carp_master_down_locked(sc);
1160 	}
1161 	CURVNET_RESTORE();
1162 
1163 	CARP_UNLOCK(sc);
1164 }
1165 
1166 static void
1167 carp_master_down_locked(struct carp_softc *sc)
1168 {
1169 
1170 	CARP_LOCK_ASSERT(sc);
1171 
1172 	switch (sc->sc_state) {
1173 	case BACKUP:
1174 		carp_set_state(sc, MASTER);
1175 		carp_send_ad_locked(sc);
1176 #ifdef INET
1177 		carp_send_arp(sc);
1178 #endif
1179 #ifdef INET6
1180 		carp_send_na(sc);
1181 #endif
1182 		carp_setrun(sc, 0);
1183 		carp_addroute(sc);
1184 		break;
1185 	case INIT:
1186 	case MASTER:
1187 #ifdef INVARIANTS
1188 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1189 		    sc->sc_vhid,
1190 		    sc->sc_carpdev->if_xname,
1191 		    sc->sc_state ? "MASTER" : "INIT");
1192 #endif
1193 		break;
1194 	}
1195 }
1196 
1197 /*
1198  * When in backup state, af indicates whether to reset the master down timer
1199  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1200  */
1201 static void
1202 carp_setrun(struct carp_softc *sc, sa_family_t af)
1203 {
1204 	struct timeval tv;
1205 
1206 	CARP_LOCK_ASSERT(sc);
1207 
1208 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1209 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1210 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0))
1211 		return;
1212 
1213 	switch (sc->sc_state) {
1214 	case INIT:
1215 		CARP_LOG("VHID %u@%s: INIT -> BACKUP\n",
1216 		    sc->sc_vhid,
1217 		    sc->sc_carpdev->if_xname);
1218 		carp_set_state(sc, BACKUP);
1219 		carp_setrun(sc, 0);
1220 		break;
1221 	case BACKUP:
1222 		callout_stop(&sc->sc_ad_tmo);
1223 		tv.tv_sec = 3 * sc->sc_advbase;
1224 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1225 		switch (af) {
1226 #ifdef INET
1227 		case AF_INET:
1228 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1229 			    carp_master_down, sc);
1230 			break;
1231 #endif
1232 #ifdef INET6
1233 		case AF_INET6:
1234 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1235 			    carp_master_down, sc);
1236 			break;
1237 #endif
1238 		default:
1239 #ifdef INET
1240 			if (sc->sc_naddrs)
1241 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1242 				    carp_master_down, sc);
1243 #endif
1244 #ifdef INET6
1245 			if (sc->sc_naddrs6)
1246 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1247 				    carp_master_down, sc);
1248 #endif
1249 			break;
1250 		}
1251 		break;
1252 	case MASTER:
1253 		tv.tv_sec = sc->sc_advbase;
1254 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1255 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1256 		    carp_send_ad, sc);
1257 		break;
1258 	}
1259 }
1260 
1261 /*
1262  * Setup multicast structures.
1263  */
1264 static int
1265 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1266 {
1267 	struct ifnet *ifp = cif->cif_ifp;
1268 	int error = 0;
1269 
1270 	CIF_LOCK_ASSERT(cif);
1271 
1272 	switch (sa) {
1273 #ifdef INET
1274 	case AF_INET:
1275 	    {
1276 		struct ip_moptions *imo = &cif->cif_imo;
1277 		struct in_addr addr;
1278 
1279 		if (imo->imo_membership)
1280 			return (0);
1281 
1282 		imo->imo_membership = (struct in_multi **)malloc(
1283 		    (sizeof(struct in_multi *) * IP_MIN_MEMBERSHIPS), M_CARP,
1284 		    M_NOWAIT);
1285 		if (imo->imo_membership == NULL)
1286 			return (ENOMEM);
1287 		imo->imo_mfilters = NULL;
1288 		imo->imo_max_memberships = IP_MIN_MEMBERSHIPS;
1289 		imo->imo_multicast_vif = -1;
1290 
1291 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1292 		if ((error = in_joingroup(ifp, &addr, NULL,
1293 		    &imo->imo_membership[0])) != 0) {
1294 			free(imo->imo_membership, M_CARP);
1295 			break;
1296 		}
1297 		imo->imo_num_memberships++;
1298 		imo->imo_multicast_ifp = ifp;
1299 		imo->imo_multicast_ttl = CARP_DFLTTL;
1300 		imo->imo_multicast_loop = 0;
1301 		break;
1302 	   }
1303 #endif
1304 #ifdef INET6
1305 	case AF_INET6:
1306 	    {
1307 		struct ip6_moptions *im6o = &cif->cif_im6o;
1308 		struct in6_addr in6;
1309 		struct in6_multi *in6m;
1310 
1311 		if (im6o->im6o_membership)
1312 			return (0);
1313 
1314 		im6o->im6o_membership = (struct in6_multi **)malloc(
1315 		    (sizeof(struct in6_multi *) * IPV6_MIN_MEMBERSHIPS), M_CARP,
1316 		    M_ZERO | M_NOWAIT);
1317 		if (im6o->im6o_membership == NULL)
1318 			return (ENOMEM);
1319 		im6o->im6o_mfilters = NULL;
1320 		im6o->im6o_max_memberships = IPV6_MIN_MEMBERSHIPS;
1321 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1322 		im6o->im6o_multicast_ifp = ifp;
1323 
1324 		/* Join IPv6 CARP multicast group. */
1325 		bzero(&in6, sizeof(in6));
1326 		in6.s6_addr16[0] = htons(0xff02);
1327 		in6.s6_addr8[15] = 0x12;
1328 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1329 			free(im6o->im6o_membership, M_CARP);
1330 			break;
1331 		}
1332 		in6m = NULL;
1333 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1334 			free(im6o->im6o_membership, M_CARP);
1335 			break;
1336 		}
1337 		im6o->im6o_membership[0] = in6m;
1338 		im6o->im6o_num_memberships++;
1339 
1340 		/* Join solicited multicast address. */
1341 		bzero(&in6, sizeof(in6));
1342 		in6.s6_addr16[0] = htons(0xff02);
1343 		in6.s6_addr32[1] = 0;
1344 		in6.s6_addr32[2] = htonl(1);
1345 		in6.s6_addr32[3] = 0;
1346 		in6.s6_addr8[12] = 0xff;
1347 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1348 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1349 			free(im6o->im6o_membership, M_CARP);
1350 			break;
1351 		}
1352 		in6m = NULL;
1353 		if ((error = in6_mc_join(ifp, &in6, NULL, &in6m, 0)) != 0) {
1354 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1355 			free(im6o->im6o_membership, M_CARP);
1356 			break;
1357 		}
1358 		im6o->im6o_membership[1] = in6m;
1359 		im6o->im6o_num_memberships++;
1360 		break;
1361 	    }
1362 #endif
1363 	}
1364 
1365 	return (error);
1366 }
1367 
1368 /*
1369  * Free multicast structures.
1370  */
1371 static void
1372 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1373 {
1374 
1375 	CIF_LOCK_ASSERT(cif);
1376 	switch (sa) {
1377 #ifdef INET
1378 	case AF_INET:
1379 		if (cif->cif_naddrs == 0) {
1380 			struct ip_moptions *imo = &cif->cif_imo;
1381 
1382 			in_leavegroup(imo->imo_membership[0], NULL);
1383 			KASSERT(imo->imo_mfilters == NULL,
1384 			    ("%s: imo_mfilters != NULL", __func__));
1385 			free(imo->imo_membership, M_CARP);
1386 			imo->imo_membership = NULL;
1387 
1388 		}
1389 		break;
1390 #endif
1391 #ifdef INET6
1392 	case AF_INET6:
1393 		if (cif->cif_naddrs6 == 0) {
1394 			struct ip6_moptions *im6o = &cif->cif_im6o;
1395 
1396 			in6_mc_leave(im6o->im6o_membership[0], NULL);
1397 			in6_mc_leave(im6o->im6o_membership[1], NULL);
1398 			KASSERT(im6o->im6o_mfilters == NULL,
1399 			    ("%s: im6o_mfilters != NULL", __func__));
1400 			free(im6o->im6o_membership, M_CARP);
1401 			im6o->im6o_membership = NULL;
1402 		}
1403 		break;
1404 #endif
1405 	}
1406 }
1407 
1408 int
1409 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1410 {
1411 	struct m_tag *mtag;
1412 	struct carp_softc *sc;
1413 
1414 	if (!sa)
1415 		return (0);
1416 
1417 	switch (sa->sa_family) {
1418 #ifdef INET
1419 	case AF_INET:
1420 		break;
1421 #endif
1422 #ifdef INET6
1423 	case AF_INET6:
1424 		break;
1425 #endif
1426 	default:
1427 		return (0);
1428 	}
1429 
1430 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1431 	if (mtag == NULL)
1432 		return (0);
1433 
1434 	bcopy(mtag + 1, &sc, sizeof(sc));
1435 
1436 	/* Set the source MAC address to the Virtual Router MAC Address. */
1437 	switch (ifp->if_type) {
1438 	case IFT_ETHER:
1439 	case IFT_BRIDGE:
1440 	case IFT_L2VLAN: {
1441 			struct ether_header *eh;
1442 
1443 			eh = mtod(m, struct ether_header *);
1444 			eh->ether_shost[0] = 0;
1445 			eh->ether_shost[1] = 0;
1446 			eh->ether_shost[2] = 0x5e;
1447 			eh->ether_shost[3] = 0;
1448 			eh->ether_shost[4] = 1;
1449 			eh->ether_shost[5] = sc->sc_vhid;
1450 		}
1451 		break;
1452 	case IFT_FDDI: {
1453 			struct fddi_header *fh;
1454 
1455 			fh = mtod(m, struct fddi_header *);
1456 			fh->fddi_shost[0] = 0;
1457 			fh->fddi_shost[1] = 0;
1458 			fh->fddi_shost[2] = 0x5e;
1459 			fh->fddi_shost[3] = 0;
1460 			fh->fddi_shost[4] = 1;
1461 			fh->fddi_shost[5] = sc->sc_vhid;
1462 		}
1463 		break;
1464 	case IFT_ISO88025: {
1465  			struct iso88025_header *th;
1466  			th = mtod(m, struct iso88025_header *);
1467 			th->iso88025_shost[0] = 3;
1468 			th->iso88025_shost[1] = 0;
1469 			th->iso88025_shost[2] = 0x40 >> (sc->sc_vhid - 1);
1470 			th->iso88025_shost[3] = 0x40000 >> (sc->sc_vhid - 1);
1471 			th->iso88025_shost[4] = 0;
1472 			th->iso88025_shost[5] = 0;
1473 		}
1474 		break;
1475 	default:
1476 		printf("%s: carp is not supported for the %d interface type\n",
1477 		    ifp->if_xname, ifp->if_type);
1478 		return (EOPNOTSUPP);
1479 	}
1480 
1481 	return (0);
1482 }
1483 
1484 static struct carp_softc*
1485 carp_alloc(struct ifnet *ifp)
1486 {
1487 	struct carp_softc *sc;
1488 	struct carp_if *cif;
1489 
1490 	if ((cif = ifp->if_carp) == NULL)
1491 		cif = carp_alloc_if(ifp);
1492 
1493 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1494 
1495 	sc->sc_advbase = CARP_DFLTINTV;
1496 	sc->sc_vhid = -1;	/* required setting */
1497 	sc->sc_init_counter = 1;
1498 	sc->sc_state = INIT;
1499 
1500 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1501 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1502 	sc->sc_carpdev = ifp;
1503 
1504 	CARP_LOCK_INIT(sc);
1505 #ifdef INET
1506 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1507 #endif
1508 #ifdef INET6
1509 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1510 #endif
1511 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1512 
1513 	CIF_LOCK(cif);
1514 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1515 	CIF_UNLOCK(cif);
1516 
1517 	mtx_lock(&carp_mtx);
1518 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1519 	mtx_unlock(&carp_mtx);
1520 
1521 	return (sc);
1522 }
1523 
1524 static int
1525 carp_grow_ifas(struct carp_softc *sc)
1526 {
1527 	struct ifaddr **new;
1528 
1529 	CARP_LOCK_ASSERT(sc);
1530 
1531 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_NOWAIT|M_ZERO);
1532 	if (new == NULL)
1533 		return (ENOMEM);
1534 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1535 	free(sc->sc_ifas, M_CARP);
1536 	sc->sc_ifas = new;
1537 	sc->sc_ifasiz *= 2;
1538 
1539 	return (0);
1540 }
1541 
1542 static void
1543 carp_destroy(struct carp_softc *sc)
1544 {
1545 	struct ifnet *ifp = sc->sc_carpdev;
1546 	struct carp_if *cif = ifp->if_carp;
1547 
1548 	CIF_LOCK_ASSERT(cif);
1549 
1550 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1551 
1552 	mtx_lock(&carp_mtx);
1553 	LIST_REMOVE(sc, sc_next);
1554 	mtx_unlock(&carp_mtx);
1555 
1556 	CARP_LOCK(sc);
1557 	if (sc->sc_suppress)
1558 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1559 	callout_drain(&sc->sc_ad_tmo);
1560 #ifdef INET
1561 	callout_drain(&sc->sc_md_tmo);
1562 #endif
1563 #ifdef INET6
1564 	callout_drain(&sc->sc_md6_tmo);
1565 #endif
1566 	CARP_LOCK_DESTROY(sc);
1567 
1568 	free(sc->sc_ifas, M_CARP);
1569 	free(sc, M_CARP);
1570 }
1571 
1572 static struct carp_if*
1573 carp_alloc_if(struct ifnet *ifp)
1574 {
1575 	struct carp_if *cif;
1576 	int error;
1577 
1578 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1579 
1580 	if ((error = ifpromisc(ifp, 1)) != 0)
1581 		printf("%s: ifpromisc(%s) failed: %d\n",
1582 		    __func__, ifp->if_xname, error);
1583 	else
1584 		cif->cif_flags |= CIF_PROMISC;
1585 
1586 	CIF_LOCK_INIT(cif);
1587 	cif->cif_ifp = ifp;
1588 	TAILQ_INIT(&cif->cif_vrs);
1589 
1590 	IF_ADDR_WLOCK(ifp);
1591 	ifp->if_carp = cif;
1592 	if_ref(ifp);
1593 	IF_ADDR_WUNLOCK(ifp);
1594 
1595 	return (cif);
1596 }
1597 
1598 static void
1599 carp_free_if(struct carp_if *cif)
1600 {
1601 	struct ifnet *ifp = cif->cif_ifp;
1602 
1603 	CIF_LOCK_ASSERT(cif);
1604 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1605 	    __func__));
1606 
1607 	IF_ADDR_WLOCK(ifp);
1608 	ifp->if_carp = NULL;
1609 	IF_ADDR_WUNLOCK(ifp);
1610 
1611 	CIF_LOCK_DESTROY(cif);
1612 
1613 	if (cif->cif_flags & CIF_PROMISC)
1614 		ifpromisc(ifp, 0);
1615 	if_rele(ifp);
1616 
1617 	free(cif, M_CARP);
1618 }
1619 
1620 static void
1621 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1622 {
1623 
1624 	CARP_LOCK(sc);
1625 	carpr->carpr_state = sc->sc_state;
1626 	carpr->carpr_vhid = sc->sc_vhid;
1627 	carpr->carpr_advbase = sc->sc_advbase;
1628 	carpr->carpr_advskew = sc->sc_advskew;
1629 	if (priv)
1630 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1631 	else
1632 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1633 	CARP_UNLOCK(sc);
1634 }
1635 
1636 int
1637 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1638 {
1639 	struct carpreq carpr;
1640 	struct ifnet *ifp;
1641 	struct carp_softc *sc = NULL;
1642 	int error = 0, locked = 0;
1643 
1644 	if ((error = copyin(ifr->ifr_data, &carpr, sizeof carpr)))
1645 		return (error);
1646 
1647 	ifp = ifunit_ref(ifr->ifr_name);
1648 	if (ifp == NULL)
1649 		return (ENXIO);
1650 
1651 	switch (ifp->if_type) {
1652 	case IFT_ETHER:
1653 	case IFT_L2VLAN:
1654 	case IFT_BRIDGE:
1655 	case IFT_FDDI:
1656 	case IFT_ISO88025:
1657 		break;
1658 	default:
1659 		error = EOPNOTSUPP;
1660 		goto out;
1661 	}
1662 
1663 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1664 		error = EADDRNOTAVAIL;
1665 		goto out;
1666 	}
1667 
1668 	switch (cmd) {
1669 	case SIOCSVH:
1670 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1671 			break;
1672 		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1673 		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1674 			error = EINVAL;
1675 			break;
1676 		}
1677 
1678 		if (ifp->if_carp) {
1679 			CIF_LOCK(ifp->if_carp);
1680 			IFNET_FOREACH_CARP(ifp, sc)
1681 				if (sc->sc_vhid == carpr.carpr_vhid)
1682 					break;
1683 			CIF_UNLOCK(ifp->if_carp);
1684 		}
1685 		if (sc == NULL) {
1686 			sc = carp_alloc(ifp);
1687 			CARP_LOCK(sc);
1688 			sc->sc_vhid = carpr.carpr_vhid;
1689 			LLADDR(&sc->sc_addr)[0] = 0;
1690 			LLADDR(&sc->sc_addr)[1] = 0;
1691 			LLADDR(&sc->sc_addr)[2] = 0x5e;
1692 			LLADDR(&sc->sc_addr)[3] = 0;
1693 			LLADDR(&sc->sc_addr)[4] = 1;
1694 			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1695 		} else
1696 			CARP_LOCK(sc);
1697 		locked = 1;
1698 		if (carpr.carpr_advbase > 0) {
1699 			if (carpr.carpr_advbase > 255 ||
1700 			    carpr.carpr_advbase < CARP_DFLTINTV) {
1701 				error = EINVAL;
1702 				break;
1703 			}
1704 			sc->sc_advbase = carpr.carpr_advbase;
1705 		}
1706 		if (carpr.carpr_advskew > 0) {
1707 			if (carpr.carpr_advskew >= 255) {
1708 				error = EINVAL;
1709 				break;
1710 			}
1711 			sc->sc_advskew = carpr.carpr_advskew;
1712 		}
1713 		if (carpr.carpr_key[0] != '\0') {
1714 			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1715 			carp_hmac_prepare(sc);
1716 		}
1717 		if (sc->sc_state != INIT &&
1718 		    carpr.carpr_state != sc->sc_state) {
1719 			switch (carpr.carpr_state) {
1720 			case BACKUP:
1721 				callout_stop(&sc->sc_ad_tmo);
1722 				carp_set_state(sc, BACKUP);
1723 				carp_setrun(sc, 0);
1724 				carp_delroute(sc);
1725 				break;
1726 			case MASTER:
1727 				carp_master_down_locked(sc);
1728 				break;
1729 			default:
1730 				break;
1731 			}
1732 		}
1733 		break;
1734 
1735 	case SIOCGVH:
1736 	    {
1737 		int priveleged;
1738 
1739 		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1740 			error = EINVAL;
1741 			break;
1742 		}
1743 		if (carpr.carpr_count < 1) {
1744 			error = EMSGSIZE;
1745 			break;
1746 		}
1747 		if (ifp->if_carp == NULL) {
1748 			error = ENOENT;
1749 			break;
1750 		}
1751 
1752 		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1753 		if (carpr.carpr_vhid != 0) {
1754 			CIF_LOCK(ifp->if_carp);
1755 			IFNET_FOREACH_CARP(ifp, sc)
1756 				if (sc->sc_vhid == carpr.carpr_vhid)
1757 					break;
1758 			CIF_UNLOCK(ifp->if_carp);
1759 			if (sc == NULL) {
1760 				error = ENOENT;
1761 				break;
1762 			}
1763 			carp_carprcp(&carpr, sc, priveleged);
1764 			error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
1765 		} else  {
1766 			int i, count;
1767 
1768 			count = 0;
1769 			CIF_LOCK(ifp->if_carp);
1770 			IFNET_FOREACH_CARP(ifp, sc)
1771 				count++;
1772 
1773 			if (count > carpr.carpr_count) {
1774 				CIF_UNLOCK(ifp->if_carp);
1775 				error = EMSGSIZE;
1776 				break;
1777 			}
1778 
1779 			i = 0;
1780 			IFNET_FOREACH_CARP(ifp, sc) {
1781 				carp_carprcp(&carpr, sc, priveleged);
1782 				carpr.carpr_count = count;
1783 				error = copyout(&carpr, ifr->ifr_data +
1784 				    (i * sizeof(carpr)), sizeof(carpr));
1785 				if (error) {
1786 					CIF_UNLOCK(ifp->if_carp);
1787 					break;
1788 				}
1789 				i++;
1790 			}
1791 			CIF_UNLOCK(ifp->if_carp);
1792 		}
1793 		break;
1794 	    }
1795 	default:
1796 		error = EINVAL;
1797 	}
1798 
1799 out:
1800 	if (locked)
1801 		CARP_UNLOCK(sc);
1802 	if_rele(ifp);
1803 
1804 	return (error);
1805 }
1806 
1807 static int
1808 carp_get_vhid(struct ifaddr *ifa)
1809 {
1810 
1811 	if (ifa == NULL || ifa->ifa_carp == NULL)
1812 		return (0);
1813 
1814 	return (ifa->ifa_carp->sc_vhid);
1815 }
1816 
1817 int
1818 carp_attach(struct ifaddr *ifa, int vhid)
1819 {
1820 	struct ifnet *ifp = ifa->ifa_ifp;
1821 	struct carp_if *cif = ifp->if_carp;
1822 	struct carp_softc *sc;
1823 	int index, error;
1824 
1825 	if (ifp->if_carp == NULL)
1826 		return (ENOPROTOOPT);
1827 
1828 	switch (ifa->ifa_addr->sa_family) {
1829 #ifdef INET
1830 	case AF_INET:
1831 #endif
1832 #ifdef INET6
1833 	case AF_INET6:
1834 #endif
1835 		break;
1836 	default:
1837 		return (EPROTOTYPE);
1838 	}
1839 
1840 	CIF_LOCK(cif);
1841 	IFNET_FOREACH_CARP(ifp, sc)
1842 		if (sc->sc_vhid == vhid)
1843 			break;
1844 	if (sc == NULL) {
1845 		CIF_UNLOCK(cif);
1846 		return (ENOENT);
1847 	}
1848 
1849 	if (ifa->ifa_carp) {
1850 		if (ifa->ifa_carp->sc_vhid != vhid)
1851 			carp_detach_locked(ifa);
1852 		else {
1853 			CIF_UNLOCK(cif);
1854 			return (0);
1855 		}
1856 	}
1857 
1858 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1859 	if (error) {
1860 		CIF_FREE(cif);
1861 		return (error);
1862 	}
1863 
1864 	CARP_LOCK(sc);
1865 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1866 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1867 		if ((error = carp_grow_ifas(sc)) != 0) {
1868 			carp_multicast_cleanup(cif,
1869 			    ifa->ifa_addr->sa_family);
1870 			CARP_UNLOCK(sc);
1871 			CIF_FREE(cif);
1872 			return (error);
1873 		}
1874 
1875 	switch (ifa->ifa_addr->sa_family) {
1876 #ifdef INET
1877 	case AF_INET:
1878 		cif->cif_naddrs++;
1879 		sc->sc_naddrs++;
1880 		break;
1881 #endif
1882 #ifdef INET6
1883 	case AF_INET6:
1884 		cif->cif_naddrs6++;
1885 		sc->sc_naddrs6++;
1886 		break;
1887 #endif
1888 	}
1889 
1890 	ifa_ref(ifa);
1891 	sc->sc_ifas[index - 1] = ifa;
1892 	ifa->ifa_carp = sc;
1893 
1894 	carp_hmac_prepare(sc);
1895 	carp_sc_state(sc);
1896 
1897 	CARP_UNLOCK(sc);
1898 	CIF_UNLOCK(cif);
1899 
1900 	return (0);
1901 }
1902 
1903 void
1904 carp_detach(struct ifaddr *ifa)
1905 {
1906 	struct ifnet *ifp = ifa->ifa_ifp;
1907 	struct carp_if *cif = ifp->if_carp;
1908 
1909 	CIF_LOCK(cif);
1910 	carp_detach_locked(ifa);
1911 	CIF_FREE(cif);
1912 }
1913 
1914 static void
1915 carp_detach_locked(struct ifaddr *ifa)
1916 {
1917 	struct ifnet *ifp = ifa->ifa_ifp;
1918 	struct carp_if *cif = ifp->if_carp;
1919 	struct carp_softc *sc = ifa->ifa_carp;
1920 	int i, index;
1921 
1922 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1923 
1924 	CIF_LOCK_ASSERT(cif);
1925 	CARP_LOCK(sc);
1926 
1927 	/* Shift array. */
1928 	index = sc->sc_naddrs + sc->sc_naddrs6;
1929 	for (i = 0; i < index; i++)
1930 		if (sc->sc_ifas[i] == ifa)
1931 			break;
1932 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1933 	for (; i < index - 1; i++)
1934 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1935 	sc->sc_ifas[index - 1] = NULL;
1936 
1937 	switch (ifa->ifa_addr->sa_family) {
1938 #ifdef INET
1939 	case AF_INET:
1940 		cif->cif_naddrs--;
1941 		sc->sc_naddrs--;
1942 		break;
1943 #endif
1944 #ifdef INET6
1945 	case AF_INET6:
1946 		cif->cif_naddrs6--;
1947 		sc->sc_naddrs6--;
1948 		break;
1949 #endif
1950 	}
1951 
1952 	carp_ifa_delroute(ifa);
1953 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
1954 
1955 	ifa->ifa_carp = NULL;
1956 	ifa_free(ifa);
1957 
1958 	carp_hmac_prepare(sc);
1959 	carp_sc_state(sc);
1960 
1961 	if (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) {
1962 		CARP_UNLOCK(sc);
1963 		carp_destroy(sc);
1964 	} else
1965 		CARP_UNLOCK(sc);
1966 }
1967 
1968 static void
1969 carp_set_state(struct carp_softc *sc, int state)
1970 {
1971 
1972 	CARP_LOCK_ASSERT(sc);
1973 
1974 	if (sc->sc_state != state) {
1975 		const char *carp_states[] = { CARP_STATES };
1976 		char subsys[IFNAMSIZ+5];
1977 
1978 		sc->sc_state = state;
1979 
1980 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
1981 		    sc->sc_carpdev->if_xname);
1982 		devctl_notify("CARP", subsys, carp_states[state], NULL);
1983 	}
1984 }
1985 
1986 static void
1987 carp_linkstate(struct ifnet *ifp)
1988 {
1989 	struct carp_softc *sc;
1990 
1991 	CIF_LOCK(ifp->if_carp);
1992 	IFNET_FOREACH_CARP(ifp, sc) {
1993 		CARP_LOCK(sc);
1994 		carp_sc_state(sc);
1995 		CARP_UNLOCK(sc);
1996 	}
1997 	CIF_UNLOCK(ifp->if_carp);
1998 }
1999 
2000 static void
2001 carp_sc_state(struct carp_softc *sc)
2002 {
2003 
2004 	CARP_LOCK_ASSERT(sc);
2005 
2006 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2007 	    !(sc->sc_carpdev->if_flags & IFF_UP)) {
2008 		callout_stop(&sc->sc_ad_tmo);
2009 #ifdef INET
2010 		callout_stop(&sc->sc_md_tmo);
2011 #endif
2012 #ifdef INET6
2013 		callout_stop(&sc->sc_md6_tmo);
2014 #endif
2015 		carp_set_state(sc, INIT);
2016 		carp_setrun(sc, 0);
2017 		if (!sc->sc_suppress)
2018 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2019 		sc->sc_suppress = 1;
2020 	} else {
2021 		carp_set_state(sc, INIT);
2022 		carp_setrun(sc, 0);
2023 		if (sc->sc_suppress)
2024 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2025 		sc->sc_suppress = 0;
2026 	}
2027 }
2028 
2029 static void
2030 carp_demote_adj(int adj, char *reason)
2031 {
2032 	atomic_add_int(&V_carp_demotion, adj);
2033 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2034 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2035 }
2036 
2037 static int
2038 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2039 {
2040 	int new, error;
2041 
2042 	new = V_carp_demotion;
2043 	error = sysctl_handle_int(oidp, &new, 0, req);
2044 	if (error || !req->newptr)
2045 		return (error);
2046 
2047 	carp_demote_adj(new, "sysctl");
2048 
2049 	return (0);
2050 }
2051 
2052 #ifdef INET
2053 extern  struct domain inetdomain;
2054 static struct protosw in_carp_protosw = {
2055 	.pr_type =		SOCK_RAW,
2056 	.pr_domain =		&inetdomain,
2057 	.pr_protocol =		IPPROTO_CARP,
2058 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2059 	.pr_input =		carp_input,
2060 	.pr_output =		rip_output,
2061 	.pr_ctloutput =		rip_ctloutput,
2062 	.pr_usrreqs =		&rip_usrreqs
2063 };
2064 #endif
2065 
2066 #ifdef INET6
2067 extern	struct domain inet6domain;
2068 static struct protosw in6_carp_protosw = {
2069 	.pr_type =		SOCK_RAW,
2070 	.pr_domain =		&inet6domain,
2071 	.pr_protocol =		IPPROTO_CARP,
2072 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2073 	.pr_input =		carp6_input,
2074 	.pr_output =		rip6_output,
2075 	.pr_ctloutput =		rip6_ctloutput,
2076 	.pr_usrreqs =		&rip6_usrreqs
2077 };
2078 #endif
2079 
2080 static void
2081 carp_mod_cleanup(void)
2082 {
2083 
2084 #ifdef INET
2085 	if (proto_reg[CARP_INET] == 0) {
2086 		(void)ipproto_unregister(IPPROTO_CARP);
2087 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2088 		proto_reg[CARP_INET] = -1;
2089 	}
2090 	carp_iamatch_p = NULL;
2091 #endif
2092 #ifdef INET6
2093 	if (proto_reg[CARP_INET6] == 0) {
2094 		(void)ip6proto_unregister(IPPROTO_CARP);
2095 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2096 		proto_reg[CARP_INET6] = -1;
2097 	}
2098 	carp_iamatch6_p = NULL;
2099 	carp_macmatch6_p = NULL;
2100 #endif
2101 	carp_ioctl_p = NULL;
2102 	carp_attach_p = NULL;
2103 	carp_detach_p = NULL;
2104 	carp_get_vhid_p = NULL;
2105 	carp_linkstate_p = NULL;
2106 	carp_forus_p = NULL;
2107 	carp_output_p = NULL;
2108 	carp_demote_adj_p = NULL;
2109 	carp_master_p = NULL;
2110 	mtx_unlock(&carp_mtx);
2111 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2112 	mtx_destroy(&carp_mtx);
2113 }
2114 
2115 static int
2116 carp_mod_load(void)
2117 {
2118 	int err;
2119 
2120 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2121 	LIST_INIT(&carp_list);
2122 	carp_get_vhid_p = carp_get_vhid;
2123 	carp_forus_p = carp_forus;
2124 	carp_output_p = carp_output;
2125 	carp_linkstate_p = carp_linkstate;
2126 	carp_ioctl_p = carp_ioctl;
2127 	carp_attach_p = carp_attach;
2128 	carp_detach_p = carp_detach;
2129 	carp_demote_adj_p = carp_demote_adj;
2130 	carp_master_p = carp_master;
2131 #ifdef INET6
2132 	carp_iamatch6_p = carp_iamatch6;
2133 	carp_macmatch6_p = carp_macmatch6;
2134 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2135 	    (struct protosw *)&in6_carp_protosw);
2136 	if (proto_reg[CARP_INET6]) {
2137 		printf("carp: error %d attaching to PF_INET6\n",
2138 		    proto_reg[CARP_INET6]);
2139 		carp_mod_cleanup();
2140 		return (proto_reg[CARP_INET6]);
2141 	}
2142 	err = ip6proto_register(IPPROTO_CARP);
2143 	if (err) {
2144 		printf("carp: error %d registering with INET6\n", err);
2145 		carp_mod_cleanup();
2146 		return (err);
2147 	}
2148 #endif
2149 #ifdef INET
2150 	carp_iamatch_p = carp_iamatch;
2151 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2152 	if (proto_reg[CARP_INET]) {
2153 		printf("carp: error %d attaching to PF_INET\n",
2154 		    proto_reg[CARP_INET]);
2155 		carp_mod_cleanup();
2156 		return (proto_reg[CARP_INET]);
2157 	}
2158 	err = ipproto_register(IPPROTO_CARP);
2159 	if (err) {
2160 		printf("carp: error %d registering with INET\n", err);
2161 		carp_mod_cleanup();
2162 		return (err);
2163 	}
2164 #endif
2165 	return (0);
2166 }
2167 
2168 static int
2169 carp_modevent(module_t mod, int type, void *data)
2170 {
2171 	switch (type) {
2172 	case MOD_LOAD:
2173 		return carp_mod_load();
2174 		/* NOTREACHED */
2175 	case MOD_UNLOAD:
2176 		mtx_lock(&carp_mtx);
2177 		if (LIST_EMPTY(&carp_list))
2178 			carp_mod_cleanup();
2179 		else {
2180 			mtx_unlock(&carp_mtx);
2181 			return (EBUSY);
2182 		}
2183 		break;
2184 
2185 	default:
2186 		return (EINVAL);
2187 	}
2188 
2189 	return (0);
2190 }
2191 
2192 static moduledata_t carp_mod = {
2193 	"carp",
2194 	carp_modevent,
2195 	0
2196 };
2197 
2198 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2199