xref: /freebsd/sys/netinet/ip_carp.c (revision 7d9ef309bd09c061e9cad8ace6f7bb4c60f087e6)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2002 Michael Shalayeff.
5  * Copyright (c) 2003 Ryan McBride.
6  * Copyright (c) 2011 Gleb Smirnoff <glebius@FreeBSD.org>
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
22  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
26  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
27  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
28  * THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_bpf.h"
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/devctl.h>
41 #include <sys/jail.h>
42 #include <sys/kernel.h>
43 #include <sys/limits.h>
44 #include <sys/malloc.h>
45 #include <sys/mbuf.h>
46 #include <sys/module.h>
47 #include <sys/priv.h>
48 #include <sys/proc.h>
49 #include <sys/socket.h>
50 #include <sys/sockio.h>
51 #include <sys/sysctl.h>
52 #include <sys/syslog.h>
53 #include <sys/taskqueue.h>
54 #include <sys/counter.h>
55 
56 #include <net/ethernet.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_private.h>
62 #include <net/if_types.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_carp_nl.h>
71 #include <netinet/ip.h>
72 #include <machine/in_cksum.h>
73 #endif
74 #ifdef INET
75 #include <netinet/ip_var.h>
76 #include <netinet/if_ether.h>
77 #endif
78 
79 #ifdef INET6
80 #include <netinet/icmp6.h>
81 #include <netinet/ip6.h>
82 #include <netinet6/in6_var.h>
83 #include <netinet6/ip6_var.h>
84 #include <netinet6/scope6_var.h>
85 #include <netinet6/nd6.h>
86 #endif
87 
88 #include <netlink/netlink.h>
89 #include <netlink/netlink_ctl.h>
90 #include <netlink/netlink_generic.h>
91 #include <netlink/netlink_message_parser.h>
92 
93 #include <crypto/sha1.h>
94 
95 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
96 
97 struct carp_softc {
98 	struct ifnet		*sc_carpdev;	/* Pointer to parent ifnet. */
99 	struct ifaddr		**sc_ifas;	/* Our ifaddrs. */
100 	struct sockaddr_dl	sc_addr;	/* Our link level address. */
101 	struct callout		sc_ad_tmo;	/* Advertising timeout. */
102 #ifdef INET
103 	struct callout		sc_md_tmo;	/* Master down timeout. */
104 #endif
105 #ifdef INET6
106 	struct callout 		sc_md6_tmo;	/* XXX: Master down timeout. */
107 #endif
108 	struct mtx		sc_mtx;
109 
110 	int			sc_vhid;
111 	int			sc_advskew;
112 	int			sc_advbase;
113 	struct in_addr		sc_carpaddr;
114 	struct in6_addr		sc_carpaddr6;
115 
116 	int			sc_naddrs;
117 	int			sc_naddrs6;
118 	int			sc_ifasiz;
119 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
120 	int			sc_suppress;
121 	int			sc_sendad_errors;
122 #define	CARP_SENDAD_MAX_ERRORS	3
123 	int			sc_sendad_success;
124 #define	CARP_SENDAD_MIN_SUCCESS 3
125 
126 	int			sc_init_counter;
127 	uint64_t		sc_counter;
128 
129 	/* authentication */
130 #define	CARP_HMAC_PAD	64
131 	unsigned char sc_key[CARP_KEY_LEN];
132 	unsigned char sc_pad[CARP_HMAC_PAD];
133 	SHA1_CTX sc_sha1;
134 
135 	TAILQ_ENTRY(carp_softc)	sc_list;	/* On the carp_if list. */
136 	LIST_ENTRY(carp_softc)	sc_next;	/* On the global list. */
137 };
138 
139 struct carp_if {
140 #ifdef INET
141 	int	cif_naddrs;
142 #endif
143 #ifdef INET6
144 	int	cif_naddrs6;
145 #endif
146 	TAILQ_HEAD(, carp_softc) cif_vrs;
147 #ifdef INET
148 	struct ip_moptions 	 cif_imo;
149 #endif
150 #ifdef INET6
151 	struct ip6_moptions 	 cif_im6o;
152 #endif
153 	struct ifnet	*cif_ifp;
154 	struct mtx	cif_mtx;
155 	uint32_t	cif_flags;
156 #define	CIF_PROMISC	0x00000001
157 };
158 
159 /* Kernel equivalent of struct carpreq, but with more fields for new features.
160  * */
161 struct carpkreq {
162 	int		carpr_count;
163 	int		carpr_vhid;
164 	int		carpr_state;
165 	int		carpr_advskew;
166 	int		carpr_advbase;
167 	unsigned char	carpr_key[CARP_KEY_LEN];
168 	/* Everything above this is identical to carpreq */
169 	struct in_addr	carpr_addr;
170 	struct in6_addr	carpr_addr6;
171 };
172 
173 /*
174  * Brief design of carp(4).
175  *
176  * Any carp-capable ifnet may have a list of carp softcs hanging off
177  * its ifp->if_carp pointer. Each softc represents one unique virtual
178  * host id, or vhid. The softc has a back pointer to the ifnet. All
179  * softcs are joined in a global list, which has quite limited use.
180  *
181  * Any interface address that takes part in CARP negotiation has a
182  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
183  * AF_INET or AF_INET6 address.
184  *
185  * Although, one can get the softc's backpointer to ifnet and traverse
186  * through its ifp->if_addrhead queue to find all interface addresses
187  * involved in CARP, we keep a growable array of ifaddr pointers. This
188  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
189  * do calls into the network stack, thus avoiding LORs.
190  *
191  * Locking:
192  *
193  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
194  * callout-driven events and ioctl()s.
195  *
196  * To traverse the list of softcs on an ifnet we use CIF_LOCK() or carp_sx.
197  * To traverse the global list we use the mutex carp_mtx.
198  *
199  * Known issues with locking:
200  *
201  * - Sending ad, we put the pointer to the softc in an mtag, and no reference
202  *   counting is done on the softc.
203  * - On module unload we may race (?) with packet processing thread
204  *   dereferencing our function pointers.
205  */
206 
207 /* Accept incoming CARP packets. */
208 VNET_DEFINE_STATIC(int, carp_allow) = 1;
209 #define	V_carp_allow	VNET(carp_allow)
210 
211 /* Set DSCP in outgoing CARP packets. */
212 VNET_DEFINE_STATIC(int, carp_dscp) = 56;
213 #define	V_carp_dscp	VNET(carp_dscp)
214 
215 /* Preempt slower nodes. */
216 VNET_DEFINE_STATIC(int, carp_preempt) = 0;
217 #define	V_carp_preempt	VNET(carp_preempt)
218 
219 /* Log level. */
220 VNET_DEFINE_STATIC(int, carp_log) = 1;
221 #define	V_carp_log	VNET(carp_log)
222 
223 /* Global advskew demotion. */
224 VNET_DEFINE_STATIC(int, carp_demotion) = 0;
225 #define	V_carp_demotion	VNET(carp_demotion)
226 
227 /* Send error demotion factor. */
228 VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
229 #define	V_carp_senderr_adj	VNET(carp_senderr_adj)
230 
231 /* Iface down demotion factor. */
232 VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
233 #define	V_carp_ifdown_adj	VNET(carp_ifdown_adj)
234 
235 static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
236 static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
237 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
238 
239 SYSCTL_NODE(_net_inet, IPPROTO_CARP, carp, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
240     "CARP");
241 SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
242     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE,
243     &VNET_NAME(carp_allow), 0, carp_allow_sysctl, "I",
244     "Accept incoming CARP packets");
245 SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
246     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
247     0, 0, carp_dscp_sysctl, "I",
248     "DSCP value for carp packets");
249 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
250     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
251 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
252     &VNET_NAME(carp_log), 0, "CARP log level");
253 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
254     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
255     0, 0, carp_demote_adj_sysctl, "I",
256     "Adjust demotion factor (skew of advskew)");
257 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
258     CTLFLAG_VNET | CTLFLAG_RW,
259     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
260 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
261     CTLFLAG_VNET | CTLFLAG_RW,
262     &VNET_NAME(carp_ifdown_adj), 0,
263     "Interface down demotion factor adjustment");
264 
265 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
266 VNET_PCPUSTAT_SYSINIT(carpstats);
267 VNET_PCPUSTAT_SYSUNINIT(carpstats);
268 
269 #define	CARPSTATS_ADD(name, val)	\
270     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
271 	sizeof(uint64_t)], (val))
272 #define	CARPSTATS_INC(name)		CARPSTATS_ADD(name, 1)
273 
274 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
275     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
276 
277 #define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
278 	NULL, MTX_DEF)
279 #define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
280 #define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
281 #define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
282 #define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
283 #define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
284 	NULL, MTX_DEF)
285 #define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
286 #define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
287 #define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
288 #define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
289 #define	CIF_FREE(cif)	do {				\
290 		CIF_LOCK(cif);				\
291 		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
292 			carp_free_if(cif);		\
293 		else					\
294 			CIF_UNLOCK(cif);		\
295 } while (0)
296 
297 #define	CARP_LOG(...)	do {				\
298 	if (V_carp_log > 0)				\
299 		log(LOG_INFO, "carp: " __VA_ARGS__);	\
300 } while (0)
301 
302 #define	CARP_DEBUG(...)	do {				\
303 	if (V_carp_log > 1)				\
304 		log(LOG_DEBUG, __VA_ARGS__);		\
305 } while (0)
306 
307 #define	IFNET_FOREACH_IFA(ifp, ifa)					\
308 	CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)	\
309 		if ((ifa)->ifa_carp != NULL)
310 
311 #define	CARP_FOREACH_IFA(sc, ifa)					\
312 	CARP_LOCK_ASSERT(sc);						\
313 	for (int _i = 0;						\
314 		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
315 		((ifa) = sc->sc_ifas[_i]) != NULL;			\
316 		++_i)
317 
318 #define	IFNET_FOREACH_CARP(ifp, sc)					\
319 	KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) ||			\
320 	    sx_xlocked(&carp_sx), ("cif_vrs not locked"));		\
321 	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
322 
323 #define	DEMOTE_ADVSKEW(sc)					\
324     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?	\
325     CARP_MAXSKEW :						\
326         (((sc)->sc_advskew + V_carp_demotion < 0) ?		\
327         0 : ((sc)->sc_advskew + V_carp_demotion)))
328 
329 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t, int);
330 static struct carp_softc
331 		*carp_alloc(struct ifnet *);
332 static void	carp_destroy(struct carp_softc *);
333 static struct carp_if
334 		*carp_alloc_if(struct ifnet *);
335 static void	carp_free_if(struct carp_if *);
336 static void	carp_set_state(struct carp_softc *, int, const char* reason);
337 static void	carp_sc_state(struct carp_softc *);
338 static void	carp_setrun(struct carp_softc *, sa_family_t);
339 static void	carp_master_down(void *);
340 static void	carp_master_down_locked(struct carp_softc *,
341     		    const char* reason);
342 static void	carp_send_ad(void *);
343 static void	carp_send_ad_locked(struct carp_softc *);
344 static void	carp_addroute(struct carp_softc *);
345 static void	carp_ifa_addroute(struct ifaddr *);
346 static void	carp_delroute(struct carp_softc *);
347 static void	carp_ifa_delroute(struct ifaddr *);
348 static void	carp_send_ad_all(void *, int);
349 static void	carp_demote_adj(int, char *);
350 
351 static LIST_HEAD(, carp_softc) carp_list;
352 static struct mtx carp_mtx;
353 static struct sx carp_sx;
354 static struct task carp_sendall_task =
355     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
356 
357 static int
358 carp_is_supported_if(if_t ifp)
359 {
360 	if (ifp == NULL)
361 		return (ENXIO);
362 
363 	switch (ifp->if_type) {
364 	case IFT_ETHER:
365 	case IFT_L2VLAN:
366 	case IFT_BRIDGE:
367 		break;
368 	default:
369 		return (EOPNOTSUPP);
370 	}
371 
372 	return (0);
373 }
374 
375 static void
376 carp_hmac_prepare(struct carp_softc *sc)
377 {
378 	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
379 	uint8_t vhid = sc->sc_vhid & 0xff;
380 	struct ifaddr *ifa;
381 	int i, found;
382 #ifdef INET
383 	struct in_addr last, cur, in;
384 #endif
385 #ifdef INET6
386 	struct in6_addr last6, cur6, in6;
387 #endif
388 
389 	CARP_LOCK_ASSERT(sc);
390 
391 	/* Compute ipad from key. */
392 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
393 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
394 	for (i = 0; i < sizeof(sc->sc_pad); i++)
395 		sc->sc_pad[i] ^= 0x36;
396 
397 	/* Precompute first part of inner hash. */
398 	SHA1Init(&sc->sc_sha1);
399 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
400 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
401 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
402 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
403 #ifdef INET
404 	cur.s_addr = 0;
405 	do {
406 		found = 0;
407 		last = cur;
408 		cur.s_addr = 0xffffffff;
409 		CARP_FOREACH_IFA(sc, ifa) {
410 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
411 			if (ifa->ifa_addr->sa_family == AF_INET &&
412 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
413 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
414 				cur.s_addr = in.s_addr;
415 				found++;
416 			}
417 		}
418 		if (found)
419 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
420 	} while (found);
421 #endif /* INET */
422 #ifdef INET6
423 	memset(&cur6, 0, sizeof(cur6));
424 	do {
425 		found = 0;
426 		last6 = cur6;
427 		memset(&cur6, 0xff, sizeof(cur6));
428 		CARP_FOREACH_IFA(sc, ifa) {
429 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
430 			if (IN6_IS_SCOPE_EMBED(&in6))
431 				in6.s6_addr16[1] = 0;
432 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
433 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
434 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
435 				cur6 = in6;
436 				found++;
437 			}
438 		}
439 		if (found)
440 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
441 	} while (found);
442 #endif /* INET6 */
443 
444 	/* convert ipad to opad */
445 	for (i = 0; i < sizeof(sc->sc_pad); i++)
446 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
447 }
448 
449 static void
450 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
451     unsigned char md[20])
452 {
453 	SHA1_CTX sha1ctx;
454 
455 	CARP_LOCK_ASSERT(sc);
456 
457 	/* fetch first half of inner hash */
458 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
459 
460 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
461 	SHA1Final(md, &sha1ctx);
462 
463 	/* outer hash */
464 	SHA1Init(&sha1ctx);
465 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
466 	SHA1Update(&sha1ctx, md, 20);
467 	SHA1Final(md, &sha1ctx);
468 }
469 
470 static int
471 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
472     unsigned char md[20])
473 {
474 	unsigned char md2[20];
475 
476 	CARP_LOCK_ASSERT(sc);
477 
478 	carp_hmac_generate(sc, counter, md2);
479 
480 	return (bcmp(md, md2, sizeof(md2)));
481 }
482 
483 /*
484  * process input packet.
485  * we have rearranged checks order compared to the rfc,
486  * but it seems more efficient this way or not possible otherwise.
487  */
488 #ifdef INET
489 static int
490 carp_input(struct mbuf **mp, int *offp, int proto)
491 {
492 	struct mbuf *m = *mp;
493 	struct ip *ip = mtod(m, struct ip *);
494 	struct carp_header *ch;
495 	int iplen, len;
496 
497 	iplen = *offp;
498 	*mp = NULL;
499 
500 	CARPSTATS_INC(carps_ipackets);
501 
502 	if (!V_carp_allow) {
503 		m_freem(m);
504 		return (IPPROTO_DONE);
505 	}
506 
507 	iplen = ip->ip_hl << 2;
508 
509 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
510 		CARPSTATS_INC(carps_badlen);
511 		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
512 		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
513 		    if_name(m->m_pkthdr.rcvif));
514 		m_freem(m);
515 		return (IPPROTO_DONE);
516 	}
517 
518 	if (iplen + sizeof(*ch) < m->m_len) {
519 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
520 			CARPSTATS_INC(carps_hdrops);
521 			CARP_DEBUG("%s: pullup failed\n", __func__);
522 			return (IPPROTO_DONE);
523 		}
524 		ip = mtod(m, struct ip *);
525 	}
526 	ch = (struct carp_header *)((char *)ip + iplen);
527 
528 	/*
529 	 * verify that the received packet length is
530 	 * equal to the CARP header
531 	 */
532 	len = iplen + sizeof(*ch);
533 	if (len > m->m_pkthdr.len) {
534 		CARPSTATS_INC(carps_badlen);
535 		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
536 		    m->m_pkthdr.len,
537 		    if_name(m->m_pkthdr.rcvif));
538 		m_freem(m);
539 		return (IPPROTO_DONE);
540 	}
541 
542 	if ((m = m_pullup(m, len)) == NULL) {
543 		CARPSTATS_INC(carps_hdrops);
544 		return (IPPROTO_DONE);
545 	}
546 	ip = mtod(m, struct ip *);
547 	ch = (struct carp_header *)((char *)ip + iplen);
548 
549 	/* verify the CARP checksum */
550 	m->m_data += iplen;
551 	if (in_cksum(m, len - iplen)) {
552 		CARPSTATS_INC(carps_badsum);
553 		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
554 		    if_name(m->m_pkthdr.rcvif));
555 		m_freem(m);
556 		return (IPPROTO_DONE);
557 	}
558 	m->m_data -= iplen;
559 
560 	carp_input_c(m, ch, AF_INET, ip->ip_ttl);
561 	return (IPPROTO_DONE);
562 }
563 #endif
564 
565 #ifdef INET6
566 static int
567 carp6_input(struct mbuf **mp, int *offp, int proto)
568 {
569 	struct mbuf *m = *mp;
570 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
571 	struct carp_header *ch;
572 	u_int len;
573 
574 	CARPSTATS_INC(carps_ipackets6);
575 
576 	if (!V_carp_allow) {
577 		m_freem(m);
578 		return (IPPROTO_DONE);
579 	}
580 
581 	/* check if received on a valid carp interface */
582 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
583 		CARPSTATS_INC(carps_badif);
584 		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
585 		    __func__, if_name(m->m_pkthdr.rcvif));
586 		m_freem(m);
587 		return (IPPROTO_DONE);
588 	}
589 
590 	/* verify that we have a complete carp packet */
591 	if (m->m_len < *offp + sizeof(*ch)) {
592 		len = m->m_len;
593 		m = m_pullup(m, *offp + sizeof(*ch));
594 		if (m == NULL) {
595 			CARPSTATS_INC(carps_badlen);
596 			CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
597 			return (IPPROTO_DONE);
598 		}
599 		ip6 = mtod(m, struct ip6_hdr *);
600 	}
601 	ch = (struct carp_header *)(mtod(m, char *) + *offp);
602 
603 	/* verify the CARP checksum */
604 	m->m_data += *offp;
605 	if (in_cksum(m, sizeof(*ch))) {
606 		CARPSTATS_INC(carps_badsum);
607 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
608 		    if_name(m->m_pkthdr.rcvif));
609 		m_freem(m);
610 		return (IPPROTO_DONE);
611 	}
612 	m->m_data -= *offp;
613 
614 	carp_input_c(m, ch, AF_INET6, ip6->ip6_hlim);
615 	return (IPPROTO_DONE);
616 }
617 #endif /* INET6 */
618 
619 /*
620  * This routine should not be necessary at all, but some switches
621  * (VMWare ESX vswitches) can echo our own packets back at us,
622  * and we must ignore them or they will cause us to drop out of
623  * MASTER mode.
624  *
625  * We cannot catch all cases of network loops.  Instead, what we
626  * do here is catch any packet that arrives with a carp header
627  * with a VHID of 0, that comes from an address that is our own.
628  * These packets are by definition "from us" (even if they are from
629  * a misconfigured host that is pretending to be us).
630  *
631  * The VHID test is outside this mini-function.
632  */
633 static int
634 carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
635 {
636 #ifdef INET
637 	struct ip *ip4;
638 	struct in_addr in4;
639 #endif
640 #ifdef INET6
641 	struct ip6_hdr *ip6;
642 	struct in6_addr in6;
643 #endif
644 
645 	switch (af) {
646 #ifdef INET
647 	case AF_INET:
648 		ip4 = mtod(m, struct ip *);
649 		in4 = ifatoia(ifa)->ia_addr.sin_addr;
650 		return (in4.s_addr == ip4->ip_src.s_addr);
651 #endif
652 #ifdef INET6
653 	case AF_INET6:
654 		ip6 = mtod(m, struct ip6_hdr *);
655 		in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
656 		return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
657 #endif
658 	default:
659 		break;
660 	}
661 	return (0);
662 }
663 
664 static void
665 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af, int ttl)
666 {
667 	struct ifnet *ifp = m->m_pkthdr.rcvif;
668 	struct ifaddr *ifa, *match;
669 	struct carp_softc *sc;
670 	uint64_t tmp_counter;
671 	struct timeval sc_tv, ch_tv;
672 	int error;
673 	bool multicast = false;
674 
675 	NET_EPOCH_ASSERT();
676 
677 	/*
678 	 * Verify that the VHID is valid on the receiving interface.
679 	 *
680 	 * There should be just one match.  If there are none
681 	 * the VHID is not valid and we drop the packet.  If
682 	 * there are multiple VHID matches, take just the first
683 	 * one, for compatibility with previous code.  While we're
684 	 * scanning, check for obvious loops in the network topology
685 	 * (these should never happen, and as noted above, we may
686 	 * miss real loops; this is just a double-check).
687 	 */
688 	error = 0;
689 	match = NULL;
690 	IFNET_FOREACH_IFA(ifp, ifa) {
691 		if (match == NULL && ifa->ifa_carp != NULL &&
692 		    ifa->ifa_addr->sa_family == af &&
693 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid)
694 			match = ifa;
695 		if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
696 			error = ELOOP;
697 	}
698 	ifa = error ? NULL : match;
699 	if (ifa != NULL)
700 		ifa_ref(ifa);
701 
702 	if (ifa == NULL) {
703 		if (error == ELOOP) {
704 			CARP_DEBUG("dropping looped packet on interface %s\n",
705 			    if_name(ifp));
706 			CARPSTATS_INC(carps_badif);	/* ??? */
707 		} else {
708 			CARPSTATS_INC(carps_badvhid);
709 		}
710 		m_freem(m);
711 		return;
712 	}
713 
714 	/* verify the CARP version. */
715 	if (ch->carp_version != CARP_VERSION) {
716 		CARPSTATS_INC(carps_badver);
717 		CARP_DEBUG("%s: invalid version %d\n", if_name(ifp),
718 		    ch->carp_version);
719 		ifa_free(ifa);
720 		m_freem(m);
721 		return;
722 	}
723 
724 	sc = ifa->ifa_carp;
725 	CARP_LOCK(sc);
726 	if (ifa->ifa_addr->sa_family == AF_INET) {
727 		multicast = IN_MULTICAST(sc->sc_carpaddr.s_addr);
728 	} else {
729 		multicast = IN6_IS_ADDR_MULTICAST(&sc->sc_carpaddr6);
730 	}
731 	ifa_free(ifa);
732 
733 	/* verify that the IP TTL is 255, but only if we're not in unicast mode. */
734 	if (multicast && ttl != CARP_DFLTTL) {
735 		CARPSTATS_INC(carps_badttl);
736 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
737 		    ttl, if_name(m->m_pkthdr.rcvif));
738 		goto out;
739 	}
740 
741 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
742 		CARPSTATS_INC(carps_badauth);
743 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
744 		    sc->sc_vhid, if_name(ifp));
745 		goto out;
746 	}
747 
748 	tmp_counter = ntohl(ch->carp_counter[0]);
749 	tmp_counter = tmp_counter<<32;
750 	tmp_counter += ntohl(ch->carp_counter[1]);
751 
752 	/* XXX Replay protection goes here */
753 
754 	sc->sc_init_counter = 0;
755 	sc->sc_counter = tmp_counter;
756 
757 	sc_tv.tv_sec = sc->sc_advbase;
758 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
759 	ch_tv.tv_sec = ch->carp_advbase;
760 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
761 
762 	switch (sc->sc_state) {
763 	case INIT:
764 		break;
765 	case MASTER:
766 		/*
767 		 * If we receive an advertisement from a master who's going to
768 		 * be more frequent than us, go into BACKUP state.
769 		 */
770 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
771 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
772 			callout_stop(&sc->sc_ad_tmo);
773 			carp_set_state(sc, BACKUP,
774 			    "more frequent advertisement received");
775 			carp_setrun(sc, 0);
776 			carp_delroute(sc);
777 		}
778 		break;
779 	case BACKUP:
780 		/*
781 		 * If we're pre-empting masters who advertise slower than us,
782 		 * and this one claims to be slower, treat him as down.
783 		 */
784 		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
785 			carp_master_down_locked(sc,
786 			    "preempting a slower master");
787 			break;
788 		}
789 
790 		/*
791 		 *  If the master is going to advertise at such a low frequency
792 		 *  that he's guaranteed to time out, we'd might as well just
793 		 *  treat him as timed out now.
794 		 */
795 		sc_tv.tv_sec = sc->sc_advbase * 3;
796 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
797 			carp_master_down_locked(sc, "master will time out");
798 			break;
799 		}
800 
801 		/*
802 		 * Otherwise, we reset the counter and wait for the next
803 		 * advertisement.
804 		 */
805 		carp_setrun(sc, af);
806 		break;
807 	}
808 
809 out:
810 	CARP_UNLOCK(sc);
811 	m_freem(m);
812 }
813 
814 static int
815 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
816 {
817 	struct m_tag *mtag;
818 
819 	if (sc->sc_init_counter) {
820 		/* this could also be seconds since unix epoch */
821 		sc->sc_counter = arc4random();
822 		sc->sc_counter = sc->sc_counter << 32;
823 		sc->sc_counter += arc4random();
824 	} else
825 		sc->sc_counter++;
826 
827 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
828 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
829 
830 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
831 
832 	/* Tag packet for carp_output */
833 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
834 	    M_NOWAIT)) == NULL) {
835 		m_freem(m);
836 		CARPSTATS_INC(carps_onomem);
837 		return (ENOMEM);
838 	}
839 	bcopy(&sc, mtag + 1, sizeof(sc));
840 	m_tag_prepend(m, mtag);
841 
842 	return (0);
843 }
844 
845 /*
846  * To avoid LORs and possible recursions this function shouldn't
847  * be called directly, but scheduled via taskqueue.
848  */
849 static void
850 carp_send_ad_all(void *ctx __unused, int pending __unused)
851 {
852 	struct carp_softc *sc;
853 	struct epoch_tracker et;
854 
855 	NET_EPOCH_ENTER(et);
856 	mtx_lock(&carp_mtx);
857 	LIST_FOREACH(sc, &carp_list, sc_next)
858 		if (sc->sc_state == MASTER) {
859 			CARP_LOCK(sc);
860 			CURVNET_SET(sc->sc_carpdev->if_vnet);
861 			carp_send_ad_locked(sc);
862 			CURVNET_RESTORE();
863 			CARP_UNLOCK(sc);
864 		}
865 	mtx_unlock(&carp_mtx);
866 	NET_EPOCH_EXIT(et);
867 }
868 
869 /* Send a periodic advertisement, executed in callout context. */
870 static void
871 carp_send_ad(void *v)
872 {
873 	struct carp_softc *sc = v;
874 	struct epoch_tracker et;
875 
876 	NET_EPOCH_ENTER(et);
877 	CARP_LOCK_ASSERT(sc);
878 	CURVNET_SET(sc->sc_carpdev->if_vnet);
879 	carp_send_ad_locked(sc);
880 	CURVNET_RESTORE();
881 	CARP_UNLOCK(sc);
882 	NET_EPOCH_EXIT(et);
883 }
884 
885 static void
886 carp_send_ad_error(struct carp_softc *sc, int error)
887 {
888 
889 	/*
890 	 * We track errors and successfull sends with this logic:
891 	 * - Any error resets success counter to 0.
892 	 * - MAX_ERRORS triggers demotion.
893 	 * - MIN_SUCCESS successes resets error counter to 0.
894 	 * - MIN_SUCCESS reverts demotion, if it was triggered before.
895 	 */
896 	if (error) {
897 		if (sc->sc_sendad_errors < INT_MAX)
898 			sc->sc_sendad_errors++;
899 		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
900 			static const char fmt[] = "send error %d on %s";
901 			char msg[sizeof(fmt) + IFNAMSIZ];
902 
903 			sprintf(msg, fmt, error, if_name(sc->sc_carpdev));
904 			carp_demote_adj(V_carp_senderr_adj, msg);
905 		}
906 		sc->sc_sendad_success = 0;
907 	} else if (sc->sc_sendad_errors > 0) {
908 		if (++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
909 			if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
910 				static const char fmt[] = "send ok on %s";
911 				char msg[sizeof(fmt) + IFNAMSIZ];
912 
913 				sprintf(msg, fmt, if_name(sc->sc_carpdev));
914 				carp_demote_adj(-V_carp_senderr_adj, msg);
915 			}
916 			sc->sc_sendad_errors = 0;
917 		}
918 	}
919 }
920 
921 /*
922  * Pick the best ifaddr on the given ifp for sending CARP
923  * advertisements.
924  *
925  * "Best" here is defined by ifa_preferred().  This function is much
926  * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
927  *
928  * (This could be simplified to return the actual address, except that
929  * it has a different format in AF_INET and AF_INET6.)
930  */
931 static struct ifaddr *
932 carp_best_ifa(int af, struct ifnet *ifp)
933 {
934 	struct ifaddr *ifa, *best;
935 
936 	NET_EPOCH_ASSERT();
937 
938 	if (af >= AF_MAX)
939 		return (NULL);
940 	best = NULL;
941 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
942 		if (ifa->ifa_addr->sa_family == af &&
943 		    (best == NULL || ifa_preferred(best, ifa)))
944 			best = ifa;
945 	}
946 	if (best != NULL)
947 		ifa_ref(best);
948 	return (best);
949 }
950 
951 static void
952 carp_send_ad_locked(struct carp_softc *sc)
953 {
954 	struct carp_header ch;
955 	struct timeval tv;
956 	struct ifaddr *ifa;
957 	struct carp_header *ch_ptr;
958 	struct mbuf *m;
959 	int len, advskew;
960 
961 	NET_EPOCH_ASSERT();
962 	CARP_LOCK_ASSERT(sc);
963 
964 	advskew = DEMOTE_ADVSKEW(sc);
965 	tv.tv_sec = sc->sc_advbase;
966 	tv.tv_usec = advskew * 1000000 / 256;
967 
968 	ch.carp_version = CARP_VERSION;
969 	ch.carp_type = CARP_ADVERTISEMENT;
970 	ch.carp_vhid = sc->sc_vhid;
971 	ch.carp_advbase = sc->sc_advbase;
972 	ch.carp_advskew = advskew;
973 	ch.carp_authlen = 7;	/* XXX DEFINE */
974 	ch.carp_pad1 = 0;	/* must be zero */
975 	ch.carp_cksum = 0;
976 
977 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
978 
979 #ifdef INET
980 	if (sc->sc_naddrs) {
981 		struct ip *ip;
982 
983 		m = m_gethdr(M_NOWAIT, MT_DATA);
984 		if (m == NULL) {
985 			CARPSTATS_INC(carps_onomem);
986 			goto resched;
987 		}
988 		len = sizeof(*ip) + sizeof(ch);
989 		m->m_pkthdr.len = len;
990 		m->m_pkthdr.rcvif = NULL;
991 		m->m_len = len;
992 		M_ALIGN(m, m->m_len);
993 		if (IN_MULTICAST(sc->sc_carpaddr.s_addr))
994 			m->m_flags |= M_MCAST;
995 		ip = mtod(m, struct ip *);
996 		ip->ip_v = IPVERSION;
997 		ip->ip_hl = sizeof(*ip) >> 2;
998 		ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
999 		ip->ip_len = htons(len);
1000 		ip->ip_off = htons(IP_DF);
1001 		ip->ip_ttl = CARP_DFLTTL;
1002 		ip->ip_p = IPPROTO_CARP;
1003 		ip->ip_sum = 0;
1004 		ip_fillid(ip);
1005 
1006 		ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
1007 		if (ifa != NULL) {
1008 			ip->ip_src.s_addr =
1009 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
1010 			ifa_free(ifa);
1011 		} else
1012 			ip->ip_src.s_addr = 0;
1013 		ip->ip_dst = sc->sc_carpaddr;
1014 
1015 		ch_ptr = (struct carp_header *)(&ip[1]);
1016 		bcopy(&ch, ch_ptr, sizeof(ch));
1017 		if (carp_prepare_ad(m, sc, ch_ptr))
1018 			goto resched;
1019 
1020 		m->m_data += sizeof(*ip);
1021 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
1022 		m->m_data -= sizeof(*ip);
1023 
1024 		CARPSTATS_INC(carps_opackets);
1025 
1026 		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
1027 		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
1028 	}
1029 #endif /* INET */
1030 #ifdef INET6
1031 	if (sc->sc_naddrs6) {
1032 		struct ip6_hdr *ip6;
1033 
1034 		m = m_gethdr(M_NOWAIT, MT_DATA);
1035 		if (m == NULL) {
1036 			CARPSTATS_INC(carps_onomem);
1037 			goto resched;
1038 		}
1039 		len = sizeof(*ip6) + sizeof(ch);
1040 		m->m_pkthdr.len = len;
1041 		m->m_pkthdr.rcvif = NULL;
1042 		m->m_len = len;
1043 		M_ALIGN(m, m->m_len);
1044 		ip6 = mtod(m, struct ip6_hdr *);
1045 		bzero(ip6, sizeof(*ip6));
1046 		ip6->ip6_vfc |= IPV6_VERSION;
1047 		/* Traffic class isn't defined in ip6 struct instead
1048 		 * it gets offset into flowid field */
1049 		ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
1050 		    IPTOS_DSCP_OFFSET));
1051 		ip6->ip6_hlim = CARP_DFLTTL;
1052 		ip6->ip6_nxt = IPPROTO_CARP;
1053 
1054 		/* set the source address */
1055 		ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1056 		if (ifa != NULL) {
1057 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1058 			    sizeof(struct in6_addr));
1059 			ifa_free(ifa);
1060 		} else
1061 			/* This should never happen with IPv6. */
1062 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1063 
1064 		/* Set the multicast destination. */
1065 		memcpy(&ip6->ip6_dst, &sc->sc_carpaddr6, sizeof(ip6->ip6_dst));
1066 		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
1067 			if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1068 				m_freem(m);
1069 				CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1070 				goto resched;
1071 			}
1072 		}
1073 
1074 		ch_ptr = (struct carp_header *)(&ip6[1]);
1075 		bcopy(&ch, ch_ptr, sizeof(ch));
1076 		if (carp_prepare_ad(m, sc, ch_ptr))
1077 			goto resched;
1078 
1079 		m->m_data += sizeof(*ip6);
1080 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1081 		m->m_data -= sizeof(*ip6);
1082 
1083 		CARPSTATS_INC(carps_opackets6);
1084 
1085 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1086 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1087 	}
1088 #endif /* INET6 */
1089 
1090 resched:
1091 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1092 }
1093 
1094 static void
1095 carp_addroute(struct carp_softc *sc)
1096 {
1097 	struct ifaddr *ifa;
1098 
1099 	CARP_FOREACH_IFA(sc, ifa)
1100 		carp_ifa_addroute(ifa);
1101 }
1102 
1103 static void
1104 carp_ifa_addroute(struct ifaddr *ifa)
1105 {
1106 
1107 	switch (ifa->ifa_addr->sa_family) {
1108 #ifdef INET
1109 	case AF_INET:
1110 		in_addprefix(ifatoia(ifa));
1111 		ifa_add_loopback_route(ifa,
1112 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1113 		break;
1114 #endif
1115 #ifdef INET6
1116 	case AF_INET6:
1117 		ifa_add_loopback_route(ifa,
1118 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1119 		nd6_add_ifa_lle(ifatoia6(ifa));
1120 		break;
1121 #endif
1122 	}
1123 }
1124 
1125 static void
1126 carp_delroute(struct carp_softc *sc)
1127 {
1128 	struct ifaddr *ifa;
1129 
1130 	CARP_FOREACH_IFA(sc, ifa)
1131 		carp_ifa_delroute(ifa);
1132 }
1133 
1134 static void
1135 carp_ifa_delroute(struct ifaddr *ifa)
1136 {
1137 
1138 	switch (ifa->ifa_addr->sa_family) {
1139 #ifdef INET
1140 	case AF_INET:
1141 		ifa_del_loopback_route(ifa,
1142 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1143 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1144 		break;
1145 #endif
1146 #ifdef INET6
1147 	case AF_INET6:
1148 		ifa_del_loopback_route(ifa,
1149 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1150 		nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1151 		break;
1152 #endif
1153 	}
1154 }
1155 
1156 int
1157 carp_master(struct ifaddr *ifa)
1158 {
1159 	struct carp_softc *sc = ifa->ifa_carp;
1160 
1161 	return (sc->sc_state == MASTER);
1162 }
1163 
1164 #ifdef INET
1165 /*
1166  * Broadcast a gratuitous ARP request containing
1167  * the virtual router MAC address for each IP address
1168  * associated with the virtual router.
1169  */
1170 static void
1171 carp_send_arp(struct carp_softc *sc)
1172 {
1173 	struct ifaddr *ifa;
1174 	struct in_addr addr;
1175 
1176 	NET_EPOCH_ASSERT();
1177 
1178 	CARP_FOREACH_IFA(sc, ifa) {
1179 		if (ifa->ifa_addr->sa_family != AF_INET)
1180 			continue;
1181 		addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1182 		arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1183 	}
1184 }
1185 
1186 int
1187 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1188 {
1189 	struct carp_softc *sc = ifa->ifa_carp;
1190 
1191 	if (sc->sc_state == MASTER) {
1192 		*enaddr = LLADDR(&sc->sc_addr);
1193 		return (1);
1194 	}
1195 
1196 	return (0);
1197 }
1198 #endif
1199 
1200 #ifdef INET6
1201 static void
1202 carp_send_na(struct carp_softc *sc)
1203 {
1204 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1205 	struct ifaddr *ifa;
1206 	struct in6_addr *in6;
1207 
1208 	CARP_FOREACH_IFA(sc, ifa) {
1209 		if (ifa->ifa_addr->sa_family != AF_INET6)
1210 			continue;
1211 
1212 		in6 = IFA_IN6(ifa);
1213 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1214 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1215 		DELAY(1000);	/* XXX */
1216 	}
1217 }
1218 
1219 /*
1220  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1221  * matches and is not a carp address.  Returns NULL otherwise.
1222  */
1223 struct ifaddr *
1224 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1225 {
1226 	struct ifaddr *ifa;
1227 
1228 	NET_EPOCH_ASSERT();
1229 
1230 	ifa = NULL;
1231 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1232 		if (ifa->ifa_addr->sa_family != AF_INET6)
1233 			continue;
1234 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1235 			continue;
1236 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1237 			ifa = NULL;
1238 		else
1239 			ifa_ref(ifa);
1240 		break;
1241 	}
1242 
1243 	return (ifa);
1244 }
1245 
1246 char *
1247 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1248 {
1249 	struct ifaddr *ifa;
1250 
1251 	NET_EPOCH_ASSERT();
1252 
1253 	IFNET_FOREACH_IFA(ifp, ifa)
1254 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1255 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1256 			struct carp_softc *sc = ifa->ifa_carp;
1257 			struct m_tag *mtag;
1258 
1259 			mtag = m_tag_get(PACKET_TAG_CARP,
1260 			    sizeof(struct carp_softc *), M_NOWAIT);
1261 			if (mtag == NULL)
1262 				/* Better a bit than nothing. */
1263 				return (LLADDR(&sc->sc_addr));
1264 
1265 			bcopy(&sc, mtag + 1, sizeof(sc));
1266 			m_tag_prepend(m, mtag);
1267 
1268 			return (LLADDR(&sc->sc_addr));
1269 		}
1270 
1271 	return (NULL);
1272 }
1273 #endif /* INET6 */
1274 
1275 int
1276 carp_forus(struct ifnet *ifp, u_char *dhost)
1277 {
1278 	struct carp_softc *sc;
1279 	uint8_t *ena = dhost;
1280 
1281 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1282 		return (0);
1283 
1284 	CIF_LOCK(ifp->if_carp);
1285 	IFNET_FOREACH_CARP(ifp, sc) {
1286 		/*
1287 		 * CARP_LOCK() is not here, since would protect nothing, but
1288 		 * cause deadlock with if_bridge, calling this under its lock.
1289 		 */
1290 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1291 		    ETHER_ADDR_LEN)) {
1292 			CIF_UNLOCK(ifp->if_carp);
1293 			return (1);
1294 		}
1295 	}
1296 	CIF_UNLOCK(ifp->if_carp);
1297 
1298 	return (0);
1299 }
1300 
1301 /* Master down timeout event, executed in callout context. */
1302 static void
1303 carp_master_down(void *v)
1304 {
1305 	struct carp_softc *sc = v;
1306 	struct epoch_tracker et;
1307 
1308 	NET_EPOCH_ENTER(et);
1309 	CARP_LOCK_ASSERT(sc);
1310 
1311 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1312 	if (sc->sc_state == BACKUP) {
1313 		carp_master_down_locked(sc, "master timed out");
1314 	}
1315 	CURVNET_RESTORE();
1316 
1317 	CARP_UNLOCK(sc);
1318 	NET_EPOCH_EXIT(et);
1319 }
1320 
1321 static void
1322 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1323 {
1324 
1325 	NET_EPOCH_ASSERT();
1326 	CARP_LOCK_ASSERT(sc);
1327 
1328 	switch (sc->sc_state) {
1329 	case BACKUP:
1330 		carp_set_state(sc, MASTER, reason);
1331 		carp_send_ad_locked(sc);
1332 #ifdef INET
1333 		carp_send_arp(sc);
1334 #endif
1335 #ifdef INET6
1336 		carp_send_na(sc);
1337 #endif
1338 		carp_setrun(sc, 0);
1339 		carp_addroute(sc);
1340 		break;
1341 	case INIT:
1342 	case MASTER:
1343 #ifdef INVARIANTS
1344 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1345 		    sc->sc_vhid,
1346 		    if_name(sc->sc_carpdev),
1347 		    sc->sc_state ? "MASTER" : "INIT");
1348 #endif
1349 		break;
1350 	}
1351 }
1352 
1353 /*
1354  * When in backup state, af indicates whether to reset the master down timer
1355  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1356  */
1357 static void
1358 carp_setrun(struct carp_softc *sc, sa_family_t af)
1359 {
1360 	struct timeval tv;
1361 
1362 	CARP_LOCK_ASSERT(sc);
1363 
1364 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1365 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1366 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1367 	    !V_carp_allow)
1368 		return;
1369 
1370 	switch (sc->sc_state) {
1371 	case INIT:
1372 		carp_set_state(sc, BACKUP, "initialization complete");
1373 		carp_setrun(sc, 0);
1374 		break;
1375 	case BACKUP:
1376 		callout_stop(&sc->sc_ad_tmo);
1377 		tv.tv_sec = 3 * sc->sc_advbase;
1378 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1379 		switch (af) {
1380 #ifdef INET
1381 		case AF_INET:
1382 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1383 			    carp_master_down, sc);
1384 			break;
1385 #endif
1386 #ifdef INET6
1387 		case AF_INET6:
1388 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1389 			    carp_master_down, sc);
1390 			break;
1391 #endif
1392 		default:
1393 #ifdef INET
1394 			if (sc->sc_naddrs)
1395 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1396 				    carp_master_down, sc);
1397 #endif
1398 #ifdef INET6
1399 			if (sc->sc_naddrs6)
1400 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1401 				    carp_master_down, sc);
1402 #endif
1403 			break;
1404 		}
1405 		break;
1406 	case MASTER:
1407 		tv.tv_sec = sc->sc_advbase;
1408 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1409 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1410 		    carp_send_ad, sc);
1411 		break;
1412 	}
1413 }
1414 
1415 /*
1416  * Setup multicast structures.
1417  */
1418 static int
1419 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1420 {
1421 	struct ifnet *ifp = cif->cif_ifp;
1422 	int error = 0;
1423 
1424 	switch (sa) {
1425 #ifdef INET
1426 	case AF_INET:
1427 	    {
1428 		struct ip_moptions *imo = &cif->cif_imo;
1429 		struct in_mfilter *imf;
1430 		struct in_addr addr;
1431 
1432 		if (ip_mfilter_first(&imo->imo_head) != NULL)
1433 			return (0);
1434 
1435 		imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1436 		ip_mfilter_init(&imo->imo_head);
1437 		imo->imo_multicast_vif = -1;
1438 
1439 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1440 		if ((error = in_joingroup(ifp, &addr, NULL,
1441 		    &imf->imf_inm)) != 0) {
1442 			ip_mfilter_free(imf);
1443 			break;
1444 		}
1445 
1446 		ip_mfilter_insert(&imo->imo_head, imf);
1447 		imo->imo_multicast_ifp = ifp;
1448 		imo->imo_multicast_ttl = CARP_DFLTTL;
1449 		imo->imo_multicast_loop = 0;
1450 		break;
1451 	   }
1452 #endif
1453 #ifdef INET6
1454 	case AF_INET6:
1455 	    {
1456 		struct ip6_moptions *im6o = &cif->cif_im6o;
1457 		struct in6_mfilter *im6f[2];
1458 		struct in6_addr in6;
1459 
1460 		if (ip6_mfilter_first(&im6o->im6o_head))
1461 			return (0);
1462 
1463 		im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1464 		im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1465 
1466 		ip6_mfilter_init(&im6o->im6o_head);
1467 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1468 		im6o->im6o_multicast_ifp = ifp;
1469 
1470 		/* Join IPv6 CARP multicast group. */
1471 		bzero(&in6, sizeof(in6));
1472 		in6.s6_addr16[0] = htons(0xff02);
1473 		in6.s6_addr8[15] = 0x12;
1474 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1475 			ip6_mfilter_free(im6f[0]);
1476 			ip6_mfilter_free(im6f[1]);
1477 			break;
1478 		}
1479 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1480 			ip6_mfilter_free(im6f[0]);
1481 			ip6_mfilter_free(im6f[1]);
1482 			break;
1483 		}
1484 
1485 		/* Join solicited multicast address. */
1486 		bzero(&in6, sizeof(in6));
1487 		in6.s6_addr16[0] = htons(0xff02);
1488 		in6.s6_addr32[1] = 0;
1489 		in6.s6_addr32[2] = htonl(1);
1490 		in6.s6_addr32[3] = 0;
1491 		in6.s6_addr8[12] = 0xff;
1492 
1493 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1494 			ip6_mfilter_free(im6f[0]);
1495 			ip6_mfilter_free(im6f[1]);
1496 			break;
1497 		}
1498 
1499 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1500 			in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1501 			ip6_mfilter_free(im6f[0]);
1502 			ip6_mfilter_free(im6f[1]);
1503 			break;
1504 		}
1505 		ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1506 		ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1507 		break;
1508 	    }
1509 #endif
1510 	}
1511 
1512 	return (error);
1513 }
1514 
1515 /*
1516  * Free multicast structures.
1517  */
1518 static void
1519 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1520 {
1521 #ifdef INET
1522 	struct ip_moptions *imo = &cif->cif_imo;
1523 	struct in_mfilter *imf;
1524 #endif
1525 #ifdef INET6
1526 	struct ip6_moptions *im6o = &cif->cif_im6o;
1527 	struct in6_mfilter *im6f;
1528 #endif
1529 	sx_assert(&carp_sx, SA_XLOCKED);
1530 
1531 	switch (sa) {
1532 #ifdef INET
1533 	case AF_INET:
1534 		if (cif->cif_naddrs != 0)
1535 			break;
1536 
1537 		while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1538 			ip_mfilter_remove(&imo->imo_head, imf);
1539 			in_leavegroup(imf->imf_inm, NULL);
1540 			ip_mfilter_free(imf);
1541 		}
1542 		break;
1543 #endif
1544 #ifdef INET6
1545 	case AF_INET6:
1546 		if (cif->cif_naddrs6 != 0)
1547 			break;
1548 
1549 		while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1550 			ip6_mfilter_remove(&im6o->im6o_head, im6f);
1551 			in6_leavegroup(im6f->im6f_in6m, NULL);
1552 			ip6_mfilter_free(im6f);
1553 		}
1554 		break;
1555 #endif
1556 	}
1557 }
1558 
1559 int
1560 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1561 {
1562 	struct m_tag *mtag;
1563 	struct carp_softc *sc;
1564 
1565 	if (!sa)
1566 		return (0);
1567 
1568 	switch (sa->sa_family) {
1569 #ifdef INET
1570 	case AF_INET:
1571 		break;
1572 #endif
1573 #ifdef INET6
1574 	case AF_INET6:
1575 		break;
1576 #endif
1577 	default:
1578 		return (0);
1579 	}
1580 
1581 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1582 	if (mtag == NULL)
1583 		return (0);
1584 
1585 	bcopy(mtag + 1, &sc, sizeof(sc));
1586 
1587 	switch (sa->sa_family) {
1588 	case AF_INET:
1589 		if (! IN_MULTICAST(sc->sc_carpaddr.s_addr))
1590 			return (0);
1591 		break;
1592 	case AF_INET6:
1593 		if (! IN6_IS_ADDR_MULTICAST(&sc->sc_carpaddr6))
1594 			return (0);
1595 		break;
1596 	default:
1597 		panic("Unknown af");
1598 	}
1599 
1600 	/* Set the source MAC address to the Virtual Router MAC Address. */
1601 	switch (ifp->if_type) {
1602 	case IFT_ETHER:
1603 	case IFT_BRIDGE:
1604 	case IFT_L2VLAN: {
1605 			struct ether_header *eh;
1606 
1607 			eh = mtod(m, struct ether_header *);
1608 			eh->ether_shost[0] = 0;
1609 			eh->ether_shost[1] = 0;
1610 			eh->ether_shost[2] = 0x5e;
1611 			eh->ether_shost[3] = 0;
1612 			eh->ether_shost[4] = 1;
1613 			eh->ether_shost[5] = sc->sc_vhid;
1614 		}
1615 		break;
1616 	default:
1617 		printf("%s: carp is not supported for the %d interface type\n",
1618 		    if_name(ifp), ifp->if_type);
1619 		return (EOPNOTSUPP);
1620 	}
1621 
1622 	return (0);
1623 }
1624 
1625 static struct carp_softc*
1626 carp_alloc(struct ifnet *ifp)
1627 {
1628 	struct carp_softc *sc;
1629 	struct carp_if *cif;
1630 
1631 	sx_assert(&carp_sx, SA_XLOCKED);
1632 
1633 	if ((cif = ifp->if_carp) == NULL)
1634 		cif = carp_alloc_if(ifp);
1635 
1636 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1637 
1638 	sc->sc_advbase = CARP_DFLTINTV;
1639 	sc->sc_vhid = -1;	/* required setting */
1640 	sc->sc_init_counter = 1;
1641 	sc->sc_state = INIT;
1642 
1643 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1644 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1645 	sc->sc_carpdev = ifp;
1646 
1647 	sc->sc_carpaddr.s_addr = htonl(INADDR_CARP_GROUP);
1648 	sc->sc_carpaddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
1649 	sc->sc_carpaddr6.s6_addr8[15] = 0x12;
1650 
1651 	CARP_LOCK_INIT(sc);
1652 #ifdef INET
1653 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1654 #endif
1655 #ifdef INET6
1656 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1657 #endif
1658 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1659 
1660 	CIF_LOCK(cif);
1661 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1662 	CIF_UNLOCK(cif);
1663 
1664 	mtx_lock(&carp_mtx);
1665 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1666 	mtx_unlock(&carp_mtx);
1667 
1668 	return (sc);
1669 }
1670 
1671 static void
1672 carp_grow_ifas(struct carp_softc *sc)
1673 {
1674 	struct ifaddr **new;
1675 
1676 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1677 	CARP_LOCK(sc);
1678 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1679 	free(sc->sc_ifas, M_CARP);
1680 	sc->sc_ifas = new;
1681 	sc->sc_ifasiz *= 2;
1682 	CARP_UNLOCK(sc);
1683 }
1684 
1685 static void
1686 carp_destroy(struct carp_softc *sc)
1687 {
1688 	struct ifnet *ifp = sc->sc_carpdev;
1689 	struct carp_if *cif = ifp->if_carp;
1690 
1691 	sx_assert(&carp_sx, SA_XLOCKED);
1692 
1693 	if (sc->sc_suppress)
1694 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1695 	CARP_UNLOCK(sc);
1696 
1697 	CIF_LOCK(cif);
1698 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1699 	CIF_UNLOCK(cif);
1700 
1701 	mtx_lock(&carp_mtx);
1702 	LIST_REMOVE(sc, sc_next);
1703 	mtx_unlock(&carp_mtx);
1704 
1705 	callout_drain(&sc->sc_ad_tmo);
1706 #ifdef INET
1707 	callout_drain(&sc->sc_md_tmo);
1708 #endif
1709 #ifdef INET6
1710 	callout_drain(&sc->sc_md6_tmo);
1711 #endif
1712 	CARP_LOCK_DESTROY(sc);
1713 
1714 	free(sc->sc_ifas, M_CARP);
1715 	free(sc, M_CARP);
1716 }
1717 
1718 static struct carp_if*
1719 carp_alloc_if(struct ifnet *ifp)
1720 {
1721 	struct carp_if *cif;
1722 	int error;
1723 
1724 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1725 
1726 	if ((error = ifpromisc(ifp, 1)) != 0)
1727 		printf("%s: ifpromisc(%s) failed: %d\n",
1728 		    __func__, if_name(ifp), error);
1729 	else
1730 		cif->cif_flags |= CIF_PROMISC;
1731 
1732 	CIF_LOCK_INIT(cif);
1733 	cif->cif_ifp = ifp;
1734 	TAILQ_INIT(&cif->cif_vrs);
1735 
1736 	IF_ADDR_WLOCK(ifp);
1737 	ifp->if_carp = cif;
1738 	if_ref(ifp);
1739 	IF_ADDR_WUNLOCK(ifp);
1740 
1741 	return (cif);
1742 }
1743 
1744 static void
1745 carp_free_if(struct carp_if *cif)
1746 {
1747 	struct ifnet *ifp = cif->cif_ifp;
1748 
1749 	CIF_LOCK_ASSERT(cif);
1750 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1751 	    __func__));
1752 
1753 	IF_ADDR_WLOCK(ifp);
1754 	ifp->if_carp = NULL;
1755 	IF_ADDR_WUNLOCK(ifp);
1756 
1757 	CIF_LOCK_DESTROY(cif);
1758 
1759 	if (cif->cif_flags & CIF_PROMISC)
1760 		ifpromisc(ifp, 0);
1761 	if_rele(ifp);
1762 
1763 	free(cif, M_CARP);
1764 }
1765 
1766 static bool
1767 carp_carprcp(void *arg, struct carp_softc *sc, int priv)
1768 {
1769 	struct carpreq *carpr = arg;
1770 
1771 	CARP_LOCK(sc);
1772 	carpr->carpr_state = sc->sc_state;
1773 	carpr->carpr_vhid = sc->sc_vhid;
1774 	carpr->carpr_advbase = sc->sc_advbase;
1775 	carpr->carpr_advskew = sc->sc_advskew;
1776 	if (priv)
1777 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1778 	else
1779 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1780 	CARP_UNLOCK(sc);
1781 
1782 	return (true);
1783 }
1784 
1785 static int
1786 carp_ioctl_set(if_t ifp, struct carpkreq *carpr)
1787 {
1788 	struct epoch_tracker et;
1789 	struct carp_softc *sc = NULL;
1790 	int error = 0;
1791 
1792 
1793 	if (carpr->carpr_vhid <= 0 || carpr->carpr_vhid > CARP_MAXVHID ||
1794 	    carpr->carpr_advbase < 0 || carpr->carpr_advskew < 0) {
1795 		return (EINVAL);
1796 	}
1797 
1798 	if (ifp->if_carp) {
1799 		IFNET_FOREACH_CARP(ifp, sc)
1800 			if (sc->sc_vhid == carpr->carpr_vhid)
1801 				break;
1802 	}
1803 	if (sc == NULL) {
1804 		sc = carp_alloc(ifp);
1805 		CARP_LOCK(sc);
1806 		sc->sc_vhid = carpr->carpr_vhid;
1807 		LLADDR(&sc->sc_addr)[0] = 0;
1808 		LLADDR(&sc->sc_addr)[1] = 0;
1809 		LLADDR(&sc->sc_addr)[2] = 0x5e;
1810 		LLADDR(&sc->sc_addr)[3] = 0;
1811 		LLADDR(&sc->sc_addr)[4] = 1;
1812 		LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1813 	} else
1814 		CARP_LOCK(sc);
1815 	if (carpr->carpr_advbase > 0) {
1816 		if (carpr->carpr_advbase > 255 ||
1817 		    carpr->carpr_advbase < CARP_DFLTINTV) {
1818 			error = EINVAL;
1819 			goto out;
1820 		}
1821 		sc->sc_advbase = carpr->carpr_advbase;
1822 	}
1823 	if (carpr->carpr_advskew >= 255) {
1824 		error = EINVAL;
1825 		goto out;
1826 	}
1827 	sc->sc_advskew = carpr->carpr_advskew;
1828 	if (carpr->carpr_addr.s_addr != INADDR_ANY)
1829 		sc->sc_carpaddr = carpr->carpr_addr;
1830 	if (! IN6_IS_ADDR_UNSPECIFIED(&carpr->carpr_addr6)) {
1831 		memcpy(&sc->sc_carpaddr6, &carpr->carpr_addr6,
1832 		    sizeof(sc->sc_carpaddr6));
1833 	}
1834 	if (carpr->carpr_key[0] != '\0') {
1835 		bcopy(carpr->carpr_key, sc->sc_key, sizeof(sc->sc_key));
1836 		carp_hmac_prepare(sc);
1837 	}
1838 	if (sc->sc_state != INIT &&
1839 	    carpr->carpr_state != sc->sc_state) {
1840 		switch (carpr->carpr_state) {
1841 		case BACKUP:
1842 			callout_stop(&sc->sc_ad_tmo);
1843 			carp_set_state(sc, BACKUP,
1844 			    "user requested via ifconfig");
1845 			carp_setrun(sc, 0);
1846 			carp_delroute(sc);
1847 			break;
1848 		case MASTER:
1849 			NET_EPOCH_ENTER(et);
1850 			carp_master_down_locked(sc,
1851 			    "user requested via ifconfig");
1852 			NET_EPOCH_EXIT(et);
1853 			break;
1854 		default:
1855 			break;
1856 		}
1857 	}
1858 
1859 out:
1860 	CARP_UNLOCK(sc);
1861 
1862 	return (error);
1863 }
1864 
1865 static int
1866 carp_ioctl_get(if_t ifp, struct ucred *cred, struct carpreq *carpr,
1867     bool (*outfn)(void *, struct carp_softc *, int), void *arg)
1868 {
1869 	int priveleged;
1870 	struct carp_softc *sc;
1871 
1872 	if (carpr->carpr_vhid < 0 || carpr->carpr_vhid > CARP_MAXVHID)
1873 		return (EINVAL);
1874 	if (carpr->carpr_count < 1)
1875 		return (EMSGSIZE);
1876 	if (ifp->if_carp == NULL)
1877 		return (ENOENT);
1878 
1879 	priveleged = (priv_check_cred(cred, PRIV_NETINET_CARP) == 0);
1880 	if (carpr->carpr_vhid != 0) {
1881 		IFNET_FOREACH_CARP(ifp, sc)
1882 			if (sc->sc_vhid == carpr->carpr_vhid)
1883 				break;
1884 		if (sc == NULL)
1885 			return (ENOENT);
1886 
1887 		if (! outfn(arg, sc, priveleged))
1888 			return (ENOMEM);
1889 		carpr->carpr_count = 1;
1890 	} else  {
1891 		int count;
1892 
1893 		count = 0;
1894 		IFNET_FOREACH_CARP(ifp, sc)
1895 			count++;
1896 
1897 		if (count > carpr->carpr_count)
1898 			return (EMSGSIZE);
1899 
1900 		IFNET_FOREACH_CARP(ifp, sc) {
1901 			if (! outfn(arg, sc, priveleged))
1902 				return (ENOMEM);
1903 			carpr->carpr_count = count;
1904 		}
1905 	}
1906 
1907 	return (0);
1908 }
1909 
1910 int
1911 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1912 {
1913 	struct carpreq carpr;
1914 	struct carpkreq carprk = { };
1915 	struct ifnet *ifp;
1916 	int error = 0;
1917 
1918 	if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1919 		return (error);
1920 
1921 	ifp = ifunit_ref(ifr->ifr_name);
1922 	if ((error = carp_is_supported_if(ifp)) != 0)
1923 		goto out;
1924 
1925 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1926 		error = EADDRNOTAVAIL;
1927 		goto out;
1928 	}
1929 
1930 	sx_xlock(&carp_sx);
1931 	switch (cmd) {
1932 	case SIOCSVH:
1933 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1934 			break;
1935 
1936 		memcpy(&carprk, &carpr, sizeof(carpr));
1937 		error = carp_ioctl_set(ifp, &carprk);
1938 		break;
1939 
1940 	case SIOCGVH:
1941 		error = carp_ioctl_get(ifp, td->td_ucred, &carpr,
1942 		    carp_carprcp, &carpr);
1943 		if (error == 0) {
1944 			error = copyout(&carpr,
1945 			    (char *)ifr_data_get_ptr(ifr),
1946 			    carpr.carpr_count * sizeof(carpr));
1947 		}
1948 		break;
1949 	default:
1950 		error = EINVAL;
1951 	}
1952 	sx_xunlock(&carp_sx);
1953 
1954 out:
1955 	if (ifp != NULL)
1956 		if_rele(ifp);
1957 
1958 	return (error);
1959 }
1960 
1961 static int
1962 carp_get_vhid(struct ifaddr *ifa)
1963 {
1964 
1965 	if (ifa == NULL || ifa->ifa_carp == NULL)
1966 		return (0);
1967 
1968 	return (ifa->ifa_carp->sc_vhid);
1969 }
1970 
1971 int
1972 carp_attach(struct ifaddr *ifa, int vhid)
1973 {
1974 	struct ifnet *ifp = ifa->ifa_ifp;
1975 	struct carp_if *cif = ifp->if_carp;
1976 	struct carp_softc *sc;
1977 	int index, error;
1978 
1979 	KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1980 
1981 	switch (ifa->ifa_addr->sa_family) {
1982 #ifdef INET
1983 	case AF_INET:
1984 #endif
1985 #ifdef INET6
1986 	case AF_INET6:
1987 #endif
1988 		break;
1989 	default:
1990 		return (EPROTOTYPE);
1991 	}
1992 
1993 	sx_xlock(&carp_sx);
1994 	if (ifp->if_carp == NULL) {
1995 		sx_xunlock(&carp_sx);
1996 		return (ENOPROTOOPT);
1997 	}
1998 
1999 	IFNET_FOREACH_CARP(ifp, sc)
2000 		if (sc->sc_vhid == vhid)
2001 			break;
2002 	if (sc == NULL) {
2003 		sx_xunlock(&carp_sx);
2004 		return (ENOENT);
2005 	}
2006 
2007 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
2008 	if (error) {
2009 		CIF_FREE(cif);
2010 		sx_xunlock(&carp_sx);
2011 		return (error);
2012 	}
2013 
2014 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
2015 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
2016 		carp_grow_ifas(sc);
2017 
2018 	switch (ifa->ifa_addr->sa_family) {
2019 #ifdef INET
2020 	case AF_INET:
2021 		cif->cif_naddrs++;
2022 		sc->sc_naddrs++;
2023 		break;
2024 #endif
2025 #ifdef INET6
2026 	case AF_INET6:
2027 		cif->cif_naddrs6++;
2028 		sc->sc_naddrs6++;
2029 		break;
2030 #endif
2031 	}
2032 
2033 	ifa_ref(ifa);
2034 
2035 	CARP_LOCK(sc);
2036 	sc->sc_ifas[index - 1] = ifa;
2037 	ifa->ifa_carp = sc;
2038 	carp_hmac_prepare(sc);
2039 	carp_sc_state(sc);
2040 	CARP_UNLOCK(sc);
2041 
2042 	sx_xunlock(&carp_sx);
2043 
2044 	return (0);
2045 }
2046 
2047 void
2048 carp_detach(struct ifaddr *ifa, bool keep_cif)
2049 {
2050 	struct ifnet *ifp = ifa->ifa_ifp;
2051 	struct carp_if *cif = ifp->if_carp;
2052 	struct carp_softc *sc = ifa->ifa_carp;
2053 	int i, index;
2054 
2055 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
2056 
2057 	sx_xlock(&carp_sx);
2058 
2059 	CARP_LOCK(sc);
2060 	/* Shift array. */
2061 	index = sc->sc_naddrs + sc->sc_naddrs6;
2062 	for (i = 0; i < index; i++)
2063 		if (sc->sc_ifas[i] == ifa)
2064 			break;
2065 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
2066 	for (; i < index - 1; i++)
2067 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
2068 	sc->sc_ifas[index - 1] = NULL;
2069 
2070 	switch (ifa->ifa_addr->sa_family) {
2071 #ifdef INET
2072 	case AF_INET:
2073 		cif->cif_naddrs--;
2074 		sc->sc_naddrs--;
2075 		break;
2076 #endif
2077 #ifdef INET6
2078 	case AF_INET6:
2079 		cif->cif_naddrs6--;
2080 		sc->sc_naddrs6--;
2081 		break;
2082 #endif
2083 	}
2084 
2085 	carp_ifa_delroute(ifa);
2086 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
2087 
2088 	ifa->ifa_carp = NULL;
2089 	ifa_free(ifa);
2090 
2091 	carp_hmac_prepare(sc);
2092 	carp_sc_state(sc);
2093 
2094 	if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2095 		carp_destroy(sc);
2096 	else
2097 		CARP_UNLOCK(sc);
2098 
2099 	if (!keep_cif)
2100 		CIF_FREE(cif);
2101 
2102 	sx_xunlock(&carp_sx);
2103 }
2104 
2105 static void
2106 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2107 {
2108 
2109 	CARP_LOCK_ASSERT(sc);
2110 
2111 	if (sc->sc_state != state) {
2112 		const char *carp_states[] = { CARP_STATES };
2113 		char subsys[IFNAMSIZ+5];
2114 
2115 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2116 		    if_name(sc->sc_carpdev));
2117 
2118 		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2119 		    carp_states[sc->sc_state], carp_states[state], reason);
2120 
2121 		sc->sc_state = state;
2122 
2123 		devctl_notify("CARP", subsys, carp_states[state], NULL);
2124 	}
2125 }
2126 
2127 static void
2128 carp_linkstate(struct ifnet *ifp)
2129 {
2130 	struct carp_softc *sc;
2131 
2132 	CIF_LOCK(ifp->if_carp);
2133 	IFNET_FOREACH_CARP(ifp, sc) {
2134 		CARP_LOCK(sc);
2135 		carp_sc_state(sc);
2136 		CARP_UNLOCK(sc);
2137 	}
2138 	CIF_UNLOCK(ifp->if_carp);
2139 }
2140 
2141 static void
2142 carp_sc_state(struct carp_softc *sc)
2143 {
2144 
2145 	CARP_LOCK_ASSERT(sc);
2146 
2147 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2148 	    !(sc->sc_carpdev->if_flags & IFF_UP) ||
2149 	    !V_carp_allow) {
2150 		callout_stop(&sc->sc_ad_tmo);
2151 #ifdef INET
2152 		callout_stop(&sc->sc_md_tmo);
2153 #endif
2154 #ifdef INET6
2155 		callout_stop(&sc->sc_md6_tmo);
2156 #endif
2157 		carp_set_state(sc, INIT, "hardware interface down");
2158 		carp_setrun(sc, 0);
2159 		if (!sc->sc_suppress)
2160 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2161 		sc->sc_suppress = 1;
2162 	} else {
2163 		carp_set_state(sc, INIT, "hardware interface up");
2164 		carp_setrun(sc, 0);
2165 		if (sc->sc_suppress)
2166 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2167 		sc->sc_suppress = 0;
2168 	}
2169 }
2170 
2171 static void
2172 carp_demote_adj(int adj, char *reason)
2173 {
2174 	atomic_add_int(&V_carp_demotion, adj);
2175 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2176 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2177 }
2178 
2179 static int
2180 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2181 {
2182 	int new, error;
2183 	struct carp_softc *sc;
2184 
2185 	new = V_carp_allow;
2186 	error = sysctl_handle_int(oidp, &new, 0, req);
2187 	if (error || !req->newptr)
2188 		return (error);
2189 
2190 	if (V_carp_allow != new) {
2191 		V_carp_allow = new;
2192 
2193 		mtx_lock(&carp_mtx);
2194 		LIST_FOREACH(sc, &carp_list, sc_next) {
2195 			CARP_LOCK(sc);
2196 			if (curvnet == sc->sc_carpdev->if_vnet)
2197 				carp_sc_state(sc);
2198 			CARP_UNLOCK(sc);
2199 		}
2200 		mtx_unlock(&carp_mtx);
2201 	}
2202 
2203 	return (0);
2204 }
2205 
2206 static int
2207 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2208 {
2209 	int new, error;
2210 
2211 	new = V_carp_dscp;
2212 	error = sysctl_handle_int(oidp, &new, 0, req);
2213 	if (error || !req->newptr)
2214 		return (error);
2215 
2216 	if (new < 0 || new > 63)
2217 		return (EINVAL);
2218 
2219 	V_carp_dscp = new;
2220 
2221 	return (0);
2222 }
2223 
2224 static int
2225 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2226 {
2227 	int new, error;
2228 
2229 	new = V_carp_demotion;
2230 	error = sysctl_handle_int(oidp, &new, 0, req);
2231 	if (error || !req->newptr)
2232 		return (error);
2233 
2234 	carp_demote_adj(new, "sysctl");
2235 
2236 	return (0);
2237 }
2238 
2239 static int
2240 nlattr_get_carp_key(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
2241 {
2242 	if (__predict_false(NLA_DATA_LEN(nla) > CARP_KEY_LEN))
2243 		return (EINVAL);
2244 
2245 	memcpy(target, NLA_DATA_CONST(nla), NLA_DATA_LEN(nla));
2246 	return (0);
2247 }
2248 
2249 struct carp_nl_send_args {
2250 	struct nlmsghdr *hdr;
2251 	struct nl_pstate *npt;
2252 };
2253 
2254 static bool
2255 carp_nl_send(void *arg, struct carp_softc *sc, int priv)
2256 {
2257 	struct carp_nl_send_args *nlsa = arg;
2258 	struct nlmsghdr *hdr = nlsa->hdr;
2259 	struct nl_pstate *npt = nlsa->npt;
2260 	struct nl_writer *nw = npt->nw;
2261 	struct genlmsghdr *ghdr_new;
2262 
2263 	if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) {
2264 		nlmsg_abort(nw);
2265 		return (false);
2266 	}
2267 
2268 	ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
2269 	if (ghdr_new == NULL) {
2270 		nlmsg_abort(nw);
2271 		return (false);
2272 	}
2273 
2274 	ghdr_new->cmd = CARP_NL_CMD_GET;
2275 	ghdr_new->version = 0;
2276 	ghdr_new->reserved = 0;
2277 
2278 	CARP_LOCK(sc);
2279 
2280 	nlattr_add_u32(nw, CARP_NL_VHID, sc->sc_vhid);
2281 	nlattr_add_u32(nw, CARP_NL_STATE, sc->sc_state);
2282 	nlattr_add_s32(nw, CARP_NL_ADVBASE, sc->sc_advbase);
2283 	nlattr_add_s32(nw, CARP_NL_ADVSKEW, sc->sc_advskew);
2284 	nlattr_add_in_addr(nw, CARP_NL_ADDR, &sc->sc_carpaddr);
2285 	nlattr_add_in6_addr(nw, CARP_NL_ADDR6, &sc->sc_carpaddr6);
2286 
2287 	if (priv)
2288 		nlattr_add(nw, CARP_NL_KEY, sizeof(sc->sc_key), sc->sc_key);
2289 
2290 	CARP_UNLOCK(sc);
2291 
2292 	if (! nlmsg_end(nw)) {
2293 		nlmsg_abort(nw);
2294 		return (false);
2295 	}
2296 
2297 	return (true);
2298 }
2299 
2300 struct nl_carp_parsed {
2301 	unsigned int	ifindex;
2302 	uint32_t	state;
2303 	uint32_t	vhid;
2304 	int32_t		advbase;
2305 	int32_t		advskew;
2306 	char		key[CARP_KEY_LEN];
2307 	struct in_addr	addr;
2308 	struct in6_addr	addr6;
2309 };
2310 
2311 #define	_IN(_field)	offsetof(struct genlmsghdr, _field)
2312 #define	_OUT(_field)	offsetof(struct nl_carp_parsed, _field)
2313 
2314 static const struct nlattr_parser nla_p_set[] = {
2315 	{ .type = CARP_NL_VHID, .off = _OUT(vhid), .cb = nlattr_get_uint32 },
2316 	{ .type = CARP_NL_STATE, .off = _OUT(state), .cb = nlattr_get_uint32 },
2317 	{ .type = CARP_NL_ADVBASE, .off = _OUT(advbase), .cb = nlattr_get_uint32 },
2318 	{ .type = CARP_NL_ADVSKEW, .off = _OUT(advskew), .cb = nlattr_get_uint32 },
2319 	{ .type = CARP_NL_KEY, .off = _OUT(key), .cb = nlattr_get_carp_key },
2320 	{ .type = CARP_NL_IFINDEX, .off = _OUT(ifindex), .cb = nlattr_get_uint32 },
2321 	{ .type = CARP_NL_ADDR, .off = _OUT(addr), .cb = nlattr_get_in_addr },
2322 	{ .type = CARP_NL_ADDR6, .off = _OUT(addr6), .cb = nlattr_get_in6_addr },
2323 };
2324 static const struct nlfield_parser nlf_p_set[] = {
2325 };
2326 NL_DECLARE_PARSER(carp_parser, struct genlmsghdr, nlf_p_set, nla_p_set);
2327 #undef _IN
2328 #undef _OUT
2329 
2330 
2331 static int
2332 carp_nl_get(struct nlmsghdr *hdr, struct nl_pstate *npt)
2333 {
2334 	struct nl_carp_parsed attrs = { };
2335 	struct carp_nl_send_args args;
2336 	struct carpreq carpr = { };
2337 	struct epoch_tracker et;
2338 	if_t ifp;
2339 	int error;
2340 
2341 	error = nl_parse_nlmsg(hdr, &carp_parser, npt, &attrs);
2342 	if (error != 0)
2343 		return (error);
2344 
2345 	NET_EPOCH_ENTER(et);
2346 	ifp = ifnet_byindex_ref(attrs.ifindex);
2347 	NET_EPOCH_EXIT(et);
2348 
2349 	if ((error = carp_is_supported_if(ifp)) != 0)
2350 		goto out;
2351 
2352 	hdr->nlmsg_flags |= NLM_F_MULTI;
2353 	args.hdr = hdr;
2354 	args.npt = npt;
2355 
2356 	carpr.carpr_vhid = attrs.vhid;
2357 	carpr.carpr_count = CARP_MAXVHID;
2358 
2359 	sx_xlock(&carp_sx);
2360 	error = carp_ioctl_get(ifp, nlp_get_cred(npt->nlp), &carpr,
2361 	    carp_nl_send, &args);
2362 	sx_xunlock(&carp_sx);
2363 
2364 	if (! nlmsg_end_dump(npt->nw, error, hdr))
2365 		error = ENOMEM;
2366 
2367 out:
2368 	if (ifp != NULL)
2369 		if_rele(ifp);
2370 
2371 	return (error);
2372 }
2373 
2374 static int
2375 carp_nl_set(struct nlmsghdr *hdr, struct nl_pstate *npt)
2376 {
2377 	struct nl_carp_parsed attrs = { };
2378 	struct carpkreq carpr;
2379 	struct epoch_tracker et;
2380 	if_t ifp;
2381 	int error;
2382 
2383 	error = nl_parse_nlmsg(hdr, &carp_parser, npt, &attrs);
2384 	if (error != 0)
2385 		return (error);
2386 
2387 	if (attrs.vhid <= 0 || attrs.vhid > CARP_MAXVHID)
2388 		return (EINVAL);
2389 	if (attrs.state > CARP_MAXSTATE)
2390 		return (EINVAL);
2391 	if (attrs.advbase < 0 || attrs.advskew < 0)
2392 		return (EINVAL);
2393 	if (attrs.advbase > 255)
2394 		return (EINVAL);
2395 	if (attrs.advskew >= 255)
2396 		return (EINVAL);
2397 
2398 	NET_EPOCH_ENTER(et);
2399 	ifp = ifnet_byindex_ref(attrs.ifindex);
2400 	NET_EPOCH_EXIT(et);
2401 
2402 	if ((error = carp_is_supported_if(ifp)) != 0)
2403 		goto out;
2404 
2405 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
2406 		error = EADDRNOTAVAIL;
2407 		goto out;
2408 	}
2409 
2410 	carpr.carpr_count = 1;
2411 	carpr.carpr_vhid = attrs.vhid;
2412 	carpr.carpr_state = attrs.state;
2413 	carpr.carpr_advbase = attrs.advbase;
2414 	carpr.carpr_advskew = attrs.advskew;
2415 	carpr.carpr_addr = attrs.addr;
2416 	carpr.carpr_addr6 = attrs.addr6;
2417 
2418 	memcpy(&carpr.carpr_key, &attrs.key, sizeof(attrs.key));
2419 
2420 	sx_xlock(&carp_sx);
2421 	error = carp_ioctl_set(ifp, &carpr);
2422 	sx_xunlock(&carp_sx);
2423 
2424 out:
2425 	if (ifp != NULL)
2426 		if_rele(ifp);
2427 
2428 	return (error);
2429 }
2430 
2431 static const struct nlhdr_parser *all_parsers[] = {
2432 	&carp_parser
2433 };
2434 
2435 static const struct genl_cmd carp_cmds[] = {
2436 	{
2437 		.cmd_num = CARP_NL_CMD_GET,
2438 		.cmd_name = "SIOCGVH",
2439 		.cmd_cb = carp_nl_get,
2440 		.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP |
2441 		    GENL_CMD_CAP_HASPOL,
2442 	},
2443 	{
2444 		.cmd_num = CARP_NL_CMD_SET,
2445 		.cmd_name = "SIOCSVH",
2446 		.cmd_cb = carp_nl_set,
2447 		.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_HASPOL,
2448 		.cmd_priv = PRIV_NETINET_CARP,
2449 	},
2450 };
2451 
2452 static void
2453 carp_nl_register(void)
2454 {
2455 	bool ret __diagused;
2456 	int family_id __diagused;
2457 
2458 	NL_VERIFY_PARSERS(all_parsers);
2459 	family_id = genl_register_family(CARP_NL_FAMILY_NAME, 0, 2,
2460 	    CARP_NL_CMD_MAX);
2461 	MPASS(family_id != 0);
2462 
2463 	ret = genl_register_cmds(CARP_NL_FAMILY_NAME, carp_cmds,
2464 	    NL_ARRAY_LEN(carp_cmds));
2465 	MPASS(ret);
2466 }
2467 
2468 static void
2469 carp_nl_unregister(void)
2470 {
2471 	genl_unregister_family(CARP_NL_FAMILY_NAME);
2472 }
2473 
2474 static void
2475 carp_mod_cleanup(void)
2476 {
2477 
2478 	carp_nl_unregister();
2479 
2480 #ifdef INET
2481 	(void)ipproto_unregister(IPPROTO_CARP);
2482 	carp_iamatch_p = NULL;
2483 #endif
2484 #ifdef INET6
2485 	(void)ip6proto_unregister(IPPROTO_CARP);
2486 	carp_iamatch6_p = NULL;
2487 	carp_macmatch6_p = NULL;
2488 #endif
2489 	carp_ioctl_p = NULL;
2490 	carp_attach_p = NULL;
2491 	carp_detach_p = NULL;
2492 	carp_get_vhid_p = NULL;
2493 	carp_linkstate_p = NULL;
2494 	carp_forus_p = NULL;
2495 	carp_output_p = NULL;
2496 	carp_demote_adj_p = NULL;
2497 	carp_master_p = NULL;
2498 	mtx_unlock(&carp_mtx);
2499 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2500 	mtx_destroy(&carp_mtx);
2501 	sx_destroy(&carp_sx);
2502 }
2503 
2504 static void
2505 ipcarp_sysinit(void)
2506 {
2507 
2508 	/* Load allow as tunable so to postpone carp start after module load */
2509 	TUNABLE_INT_FETCH("net.inet.carp.allow", &V_carp_allow);
2510 }
2511 VNET_SYSINIT(ip_carp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipcarp_sysinit, NULL);
2512 
2513 static int
2514 carp_mod_load(void)
2515 {
2516 	int err;
2517 
2518 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2519 	sx_init(&carp_sx, "carp_sx");
2520 	LIST_INIT(&carp_list);
2521 	carp_get_vhid_p = carp_get_vhid;
2522 	carp_forus_p = carp_forus;
2523 	carp_output_p = carp_output;
2524 	carp_linkstate_p = carp_linkstate;
2525 	carp_ioctl_p = carp_ioctl;
2526 	carp_attach_p = carp_attach;
2527 	carp_detach_p = carp_detach;
2528 	carp_demote_adj_p = carp_demote_adj;
2529 	carp_master_p = carp_master;
2530 #ifdef INET6
2531 	carp_iamatch6_p = carp_iamatch6;
2532 	carp_macmatch6_p = carp_macmatch6;
2533 	err = ip6proto_register(IPPROTO_CARP, carp6_input, NULL);
2534 	if (err) {
2535 		printf("carp: error %d registering with INET6\n", err);
2536 		carp_mod_cleanup();
2537 		return (err);
2538 	}
2539 #endif
2540 #ifdef INET
2541 	carp_iamatch_p = carp_iamatch;
2542 	err = ipproto_register(IPPROTO_CARP, carp_input, NULL);
2543 	if (err) {
2544 		printf("carp: error %d registering with INET\n", err);
2545 		carp_mod_cleanup();
2546 		return (err);
2547 	}
2548 #endif
2549 
2550 	carp_nl_register();
2551 
2552 	return (0);
2553 }
2554 
2555 static int
2556 carp_modevent(module_t mod, int type, void *data)
2557 {
2558 	switch (type) {
2559 	case MOD_LOAD:
2560 		return carp_mod_load();
2561 		/* NOTREACHED */
2562 	case MOD_UNLOAD:
2563 		mtx_lock(&carp_mtx);
2564 		if (LIST_EMPTY(&carp_list))
2565 			carp_mod_cleanup();
2566 		else {
2567 			mtx_unlock(&carp_mtx);
2568 			return (EBUSY);
2569 		}
2570 		break;
2571 
2572 	default:
2573 		return (EINVAL);
2574 	}
2575 
2576 	return (0);
2577 }
2578 
2579 static moduledata_t carp_mod = {
2580 	"carp",
2581 	carp_modevent,
2582 	0
2583 };
2584 
2585 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2586