xref: /freebsd/sys/netinet/ip_carp.c (revision d0b2dbfa0ecf2bbc9709efc5e20baf8e4b44bbbf)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
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 "opt_netlink.h"
32 
33 #include <sys/cdefs.h>
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 		    IN6_IS_ADDR_LINKLOCAL(&ip6->ip6_dst)) {
1068 			if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1069 				m_freem(m);
1070 				CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1071 				goto resched;
1072 			}
1073 		}
1074 
1075 		ch_ptr = (struct carp_header *)(&ip6[1]);
1076 		bcopy(&ch, ch_ptr, sizeof(ch));
1077 		if (carp_prepare_ad(m, sc, ch_ptr))
1078 			goto resched;
1079 
1080 		m->m_data += sizeof(*ip6);
1081 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1082 		m->m_data -= sizeof(*ip6);
1083 
1084 		CARPSTATS_INC(carps_opackets6);
1085 
1086 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1087 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1088 	}
1089 #endif /* INET6 */
1090 
1091 resched:
1092 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1093 }
1094 
1095 static void
1096 carp_addroute(struct carp_softc *sc)
1097 {
1098 	struct ifaddr *ifa;
1099 
1100 	CARP_FOREACH_IFA(sc, ifa)
1101 		carp_ifa_addroute(ifa);
1102 }
1103 
1104 static void
1105 carp_ifa_addroute(struct ifaddr *ifa)
1106 {
1107 
1108 	switch (ifa->ifa_addr->sa_family) {
1109 #ifdef INET
1110 	case AF_INET:
1111 		in_addprefix(ifatoia(ifa));
1112 		ifa_add_loopback_route(ifa,
1113 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1114 		break;
1115 #endif
1116 #ifdef INET6
1117 	case AF_INET6:
1118 		ifa_add_loopback_route(ifa,
1119 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1120 		nd6_add_ifa_lle(ifatoia6(ifa));
1121 		break;
1122 #endif
1123 	}
1124 }
1125 
1126 static void
1127 carp_delroute(struct carp_softc *sc)
1128 {
1129 	struct ifaddr *ifa;
1130 
1131 	CARP_FOREACH_IFA(sc, ifa)
1132 		carp_ifa_delroute(ifa);
1133 }
1134 
1135 static void
1136 carp_ifa_delroute(struct ifaddr *ifa)
1137 {
1138 
1139 	switch (ifa->ifa_addr->sa_family) {
1140 #ifdef INET
1141 	case AF_INET:
1142 		ifa_del_loopback_route(ifa,
1143 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1144 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1145 		break;
1146 #endif
1147 #ifdef INET6
1148 	case AF_INET6:
1149 		ifa_del_loopback_route(ifa,
1150 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1151 		nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1152 		break;
1153 #endif
1154 	}
1155 }
1156 
1157 int
1158 carp_master(struct ifaddr *ifa)
1159 {
1160 	struct carp_softc *sc = ifa->ifa_carp;
1161 
1162 	return (sc->sc_state == MASTER);
1163 }
1164 
1165 #ifdef INET
1166 /*
1167  * Broadcast a gratuitous ARP request containing
1168  * the virtual router MAC address for each IP address
1169  * associated with the virtual router.
1170  */
1171 static void
1172 carp_send_arp(struct carp_softc *sc)
1173 {
1174 	struct ifaddr *ifa;
1175 	struct in_addr addr;
1176 
1177 	NET_EPOCH_ASSERT();
1178 
1179 	CARP_FOREACH_IFA(sc, ifa) {
1180 		if (ifa->ifa_addr->sa_family != AF_INET)
1181 			continue;
1182 		addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1183 		arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1184 	}
1185 }
1186 
1187 int
1188 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1189 {
1190 	struct carp_softc *sc = ifa->ifa_carp;
1191 
1192 	if (sc->sc_state == MASTER) {
1193 		*enaddr = LLADDR(&sc->sc_addr);
1194 		return (1);
1195 	}
1196 
1197 	return (0);
1198 }
1199 #endif
1200 
1201 #ifdef INET6
1202 static void
1203 carp_send_na(struct carp_softc *sc)
1204 {
1205 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1206 	struct ifaddr *ifa;
1207 	struct in6_addr *in6;
1208 
1209 	CARP_FOREACH_IFA(sc, ifa) {
1210 		if (ifa->ifa_addr->sa_family != AF_INET6)
1211 			continue;
1212 
1213 		in6 = IFA_IN6(ifa);
1214 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1215 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1216 		DELAY(1000);	/* XXX */
1217 	}
1218 }
1219 
1220 /*
1221  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1222  * matches and is not a carp address.  Returns NULL otherwise.
1223  */
1224 struct ifaddr *
1225 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1226 {
1227 	struct ifaddr *ifa;
1228 
1229 	NET_EPOCH_ASSERT();
1230 
1231 	ifa = NULL;
1232 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1233 		if (ifa->ifa_addr->sa_family != AF_INET6)
1234 			continue;
1235 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1236 			continue;
1237 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1238 			ifa = NULL;
1239 		else
1240 			ifa_ref(ifa);
1241 		break;
1242 	}
1243 
1244 	return (ifa);
1245 }
1246 
1247 char *
1248 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1249 {
1250 	struct ifaddr *ifa;
1251 
1252 	NET_EPOCH_ASSERT();
1253 
1254 	IFNET_FOREACH_IFA(ifp, ifa)
1255 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1256 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1257 			struct carp_softc *sc = ifa->ifa_carp;
1258 			struct m_tag *mtag;
1259 
1260 			mtag = m_tag_get(PACKET_TAG_CARP,
1261 			    sizeof(struct carp_softc *), M_NOWAIT);
1262 			if (mtag == NULL)
1263 				/* Better a bit than nothing. */
1264 				return (LLADDR(&sc->sc_addr));
1265 
1266 			bcopy(&sc, mtag + 1, sizeof(sc));
1267 			m_tag_prepend(m, mtag);
1268 
1269 			return (LLADDR(&sc->sc_addr));
1270 		}
1271 
1272 	return (NULL);
1273 }
1274 #endif /* INET6 */
1275 
1276 int
1277 carp_forus(struct ifnet *ifp, u_char *dhost)
1278 {
1279 	struct carp_softc *sc;
1280 	uint8_t *ena = dhost;
1281 
1282 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1283 		return (0);
1284 
1285 	CIF_LOCK(ifp->if_carp);
1286 	IFNET_FOREACH_CARP(ifp, sc) {
1287 		/*
1288 		 * CARP_LOCK() is not here, since would protect nothing, but
1289 		 * cause deadlock with if_bridge, calling this under its lock.
1290 		 */
1291 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1292 		    ETHER_ADDR_LEN)) {
1293 			CIF_UNLOCK(ifp->if_carp);
1294 			return (1);
1295 		}
1296 	}
1297 	CIF_UNLOCK(ifp->if_carp);
1298 
1299 	return (0);
1300 }
1301 
1302 /* Master down timeout event, executed in callout context. */
1303 static void
1304 carp_master_down(void *v)
1305 {
1306 	struct carp_softc *sc = v;
1307 	struct epoch_tracker et;
1308 
1309 	NET_EPOCH_ENTER(et);
1310 	CARP_LOCK_ASSERT(sc);
1311 
1312 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1313 	if (sc->sc_state == BACKUP) {
1314 		carp_master_down_locked(sc, "master timed out");
1315 	}
1316 	CURVNET_RESTORE();
1317 
1318 	CARP_UNLOCK(sc);
1319 	NET_EPOCH_EXIT(et);
1320 }
1321 
1322 static void
1323 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1324 {
1325 
1326 	NET_EPOCH_ASSERT();
1327 	CARP_LOCK_ASSERT(sc);
1328 
1329 	switch (sc->sc_state) {
1330 	case BACKUP:
1331 		carp_set_state(sc, MASTER, reason);
1332 		carp_send_ad_locked(sc);
1333 #ifdef INET
1334 		carp_send_arp(sc);
1335 #endif
1336 #ifdef INET6
1337 		carp_send_na(sc);
1338 #endif
1339 		carp_setrun(sc, 0);
1340 		carp_addroute(sc);
1341 		break;
1342 	case INIT:
1343 	case MASTER:
1344 #ifdef INVARIANTS
1345 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1346 		    sc->sc_vhid,
1347 		    if_name(sc->sc_carpdev),
1348 		    sc->sc_state ? "MASTER" : "INIT");
1349 #endif
1350 		break;
1351 	}
1352 }
1353 
1354 /*
1355  * When in backup state, af indicates whether to reset the master down timer
1356  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1357  */
1358 static void
1359 carp_setrun(struct carp_softc *sc, sa_family_t af)
1360 {
1361 	struct timeval tv;
1362 
1363 	CARP_LOCK_ASSERT(sc);
1364 
1365 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1366 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1367 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1368 	    !V_carp_allow)
1369 		return;
1370 
1371 	switch (sc->sc_state) {
1372 	case INIT:
1373 		carp_set_state(sc, BACKUP, "initialization complete");
1374 		carp_setrun(sc, 0);
1375 		break;
1376 	case BACKUP:
1377 		callout_stop(&sc->sc_ad_tmo);
1378 		tv.tv_sec = 3 * sc->sc_advbase;
1379 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1380 		switch (af) {
1381 #ifdef INET
1382 		case AF_INET:
1383 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1384 			    carp_master_down, sc);
1385 			break;
1386 #endif
1387 #ifdef INET6
1388 		case AF_INET6:
1389 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1390 			    carp_master_down, sc);
1391 			break;
1392 #endif
1393 		default:
1394 #ifdef INET
1395 			if (sc->sc_naddrs)
1396 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1397 				    carp_master_down, sc);
1398 #endif
1399 #ifdef INET6
1400 			if (sc->sc_naddrs6)
1401 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1402 				    carp_master_down, sc);
1403 #endif
1404 			break;
1405 		}
1406 		break;
1407 	case MASTER:
1408 		tv.tv_sec = sc->sc_advbase;
1409 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1410 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1411 		    carp_send_ad, sc);
1412 		break;
1413 	}
1414 }
1415 
1416 /*
1417  * Setup multicast structures.
1418  */
1419 static int
1420 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1421 {
1422 	struct ifnet *ifp = cif->cif_ifp;
1423 	int error = 0;
1424 
1425 	switch (sa) {
1426 #ifdef INET
1427 	case AF_INET:
1428 	    {
1429 		struct ip_moptions *imo = &cif->cif_imo;
1430 		struct in_mfilter *imf;
1431 		struct in_addr addr;
1432 
1433 		if (ip_mfilter_first(&imo->imo_head) != NULL)
1434 			return (0);
1435 
1436 		imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1437 		ip_mfilter_init(&imo->imo_head);
1438 		imo->imo_multicast_vif = -1;
1439 
1440 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1441 		if ((error = in_joingroup(ifp, &addr, NULL,
1442 		    &imf->imf_inm)) != 0) {
1443 			ip_mfilter_free(imf);
1444 			break;
1445 		}
1446 
1447 		ip_mfilter_insert(&imo->imo_head, imf);
1448 		imo->imo_multicast_ifp = ifp;
1449 		imo->imo_multicast_ttl = CARP_DFLTTL;
1450 		imo->imo_multicast_loop = 0;
1451 		break;
1452 	   }
1453 #endif
1454 #ifdef INET6
1455 	case AF_INET6:
1456 	    {
1457 		struct ip6_moptions *im6o = &cif->cif_im6o;
1458 		struct in6_mfilter *im6f[2];
1459 		struct in6_addr in6;
1460 
1461 		if (ip6_mfilter_first(&im6o->im6o_head))
1462 			return (0);
1463 
1464 		im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1465 		im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1466 
1467 		ip6_mfilter_init(&im6o->im6o_head);
1468 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1469 		im6o->im6o_multicast_ifp = ifp;
1470 
1471 		/* Join IPv6 CARP multicast group. */
1472 		bzero(&in6, sizeof(in6));
1473 		in6.s6_addr16[0] = htons(0xff02);
1474 		in6.s6_addr8[15] = 0x12;
1475 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1476 			ip6_mfilter_free(im6f[0]);
1477 			ip6_mfilter_free(im6f[1]);
1478 			break;
1479 		}
1480 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1481 			ip6_mfilter_free(im6f[0]);
1482 			ip6_mfilter_free(im6f[1]);
1483 			break;
1484 		}
1485 
1486 		/* Join solicited multicast address. */
1487 		bzero(&in6, sizeof(in6));
1488 		in6.s6_addr16[0] = htons(0xff02);
1489 		in6.s6_addr32[1] = 0;
1490 		in6.s6_addr32[2] = htonl(1);
1491 		in6.s6_addr32[3] = 0;
1492 		in6.s6_addr8[12] = 0xff;
1493 
1494 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1495 			ip6_mfilter_free(im6f[0]);
1496 			ip6_mfilter_free(im6f[1]);
1497 			break;
1498 		}
1499 
1500 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1501 			in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1502 			ip6_mfilter_free(im6f[0]);
1503 			ip6_mfilter_free(im6f[1]);
1504 			break;
1505 		}
1506 		ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1507 		ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1508 		break;
1509 	    }
1510 #endif
1511 	}
1512 
1513 	return (error);
1514 }
1515 
1516 /*
1517  * Free multicast structures.
1518  */
1519 static void
1520 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1521 {
1522 #ifdef INET
1523 	struct ip_moptions *imo = &cif->cif_imo;
1524 	struct in_mfilter *imf;
1525 #endif
1526 #ifdef INET6
1527 	struct ip6_moptions *im6o = &cif->cif_im6o;
1528 	struct in6_mfilter *im6f;
1529 #endif
1530 	sx_assert(&carp_sx, SA_XLOCKED);
1531 
1532 	switch (sa) {
1533 #ifdef INET
1534 	case AF_INET:
1535 		if (cif->cif_naddrs != 0)
1536 			break;
1537 
1538 		while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1539 			ip_mfilter_remove(&imo->imo_head, imf);
1540 			in_leavegroup(imf->imf_inm, NULL);
1541 			ip_mfilter_free(imf);
1542 		}
1543 		break;
1544 #endif
1545 #ifdef INET6
1546 	case AF_INET6:
1547 		if (cif->cif_naddrs6 != 0)
1548 			break;
1549 
1550 		while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1551 			ip6_mfilter_remove(&im6o->im6o_head, im6f);
1552 			in6_leavegroup(im6f->im6f_in6m, NULL);
1553 			ip6_mfilter_free(im6f);
1554 		}
1555 		break;
1556 #endif
1557 	}
1558 }
1559 
1560 int
1561 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1562 {
1563 	struct m_tag *mtag;
1564 	struct carp_softc *sc;
1565 
1566 	if (!sa)
1567 		return (0);
1568 
1569 	switch (sa->sa_family) {
1570 #ifdef INET
1571 	case AF_INET:
1572 		break;
1573 #endif
1574 #ifdef INET6
1575 	case AF_INET6:
1576 		break;
1577 #endif
1578 	default:
1579 		return (0);
1580 	}
1581 
1582 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1583 	if (mtag == NULL)
1584 		return (0);
1585 
1586 	bcopy(mtag + 1, &sc, sizeof(sc));
1587 
1588 	switch (sa->sa_family) {
1589 	case AF_INET:
1590 		if (! IN_MULTICAST(ntohl(sc->sc_carpaddr.s_addr)))
1591 			return (0);
1592 		break;
1593 	case AF_INET6:
1594 		if (! IN6_IS_ADDR_MULTICAST(&sc->sc_carpaddr6))
1595 			return (0);
1596 		break;
1597 	default:
1598 		panic("Unknown af");
1599 	}
1600 
1601 	/* Set the source MAC address to the Virtual Router MAC Address. */
1602 	switch (ifp->if_type) {
1603 	case IFT_ETHER:
1604 	case IFT_BRIDGE:
1605 	case IFT_L2VLAN: {
1606 			struct ether_header *eh;
1607 
1608 			eh = mtod(m, struct ether_header *);
1609 			eh->ether_shost[0] = 0;
1610 			eh->ether_shost[1] = 0;
1611 			eh->ether_shost[2] = 0x5e;
1612 			eh->ether_shost[3] = 0;
1613 			eh->ether_shost[4] = 1;
1614 			eh->ether_shost[5] = sc->sc_vhid;
1615 		}
1616 		break;
1617 	default:
1618 		printf("%s: carp is not supported for the %d interface type\n",
1619 		    if_name(ifp), ifp->if_type);
1620 		return (EOPNOTSUPP);
1621 	}
1622 
1623 	return (0);
1624 }
1625 
1626 static struct carp_softc*
1627 carp_alloc(struct ifnet *ifp)
1628 {
1629 	struct carp_softc *sc;
1630 	struct carp_if *cif;
1631 
1632 	sx_assert(&carp_sx, SA_XLOCKED);
1633 
1634 	if ((cif = ifp->if_carp) == NULL)
1635 		cif = carp_alloc_if(ifp);
1636 
1637 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1638 
1639 	sc->sc_advbase = CARP_DFLTINTV;
1640 	sc->sc_vhid = -1;	/* required setting */
1641 	sc->sc_init_counter = 1;
1642 	sc->sc_state = INIT;
1643 
1644 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1645 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1646 	sc->sc_carpdev = ifp;
1647 
1648 	sc->sc_carpaddr.s_addr = htonl(INADDR_CARP_GROUP);
1649 	sc->sc_carpaddr6.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
1650 	sc->sc_carpaddr6.s6_addr8[15] = 0x12;
1651 
1652 	CARP_LOCK_INIT(sc);
1653 #ifdef INET
1654 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1655 #endif
1656 #ifdef INET6
1657 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1658 #endif
1659 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1660 
1661 	CIF_LOCK(cif);
1662 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1663 	CIF_UNLOCK(cif);
1664 
1665 	mtx_lock(&carp_mtx);
1666 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1667 	mtx_unlock(&carp_mtx);
1668 
1669 	return (sc);
1670 }
1671 
1672 static void
1673 carp_grow_ifas(struct carp_softc *sc)
1674 {
1675 	struct ifaddr **new;
1676 
1677 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1678 	CARP_LOCK(sc);
1679 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1680 	free(sc->sc_ifas, M_CARP);
1681 	sc->sc_ifas = new;
1682 	sc->sc_ifasiz *= 2;
1683 	CARP_UNLOCK(sc);
1684 }
1685 
1686 static void
1687 carp_destroy(struct carp_softc *sc)
1688 {
1689 	struct ifnet *ifp = sc->sc_carpdev;
1690 	struct carp_if *cif = ifp->if_carp;
1691 
1692 	sx_assert(&carp_sx, SA_XLOCKED);
1693 
1694 	if (sc->sc_suppress)
1695 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1696 	CARP_UNLOCK(sc);
1697 
1698 	CIF_LOCK(cif);
1699 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1700 	CIF_UNLOCK(cif);
1701 
1702 	mtx_lock(&carp_mtx);
1703 	LIST_REMOVE(sc, sc_next);
1704 	mtx_unlock(&carp_mtx);
1705 
1706 	callout_drain(&sc->sc_ad_tmo);
1707 #ifdef INET
1708 	callout_drain(&sc->sc_md_tmo);
1709 #endif
1710 #ifdef INET6
1711 	callout_drain(&sc->sc_md6_tmo);
1712 #endif
1713 	CARP_LOCK_DESTROY(sc);
1714 
1715 	free(sc->sc_ifas, M_CARP);
1716 	free(sc, M_CARP);
1717 }
1718 
1719 static struct carp_if*
1720 carp_alloc_if(struct ifnet *ifp)
1721 {
1722 	struct carp_if *cif;
1723 	int error;
1724 
1725 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1726 
1727 	if ((error = ifpromisc(ifp, 1)) != 0)
1728 		printf("%s: ifpromisc(%s) failed: %d\n",
1729 		    __func__, if_name(ifp), error);
1730 	else
1731 		cif->cif_flags |= CIF_PROMISC;
1732 
1733 	CIF_LOCK_INIT(cif);
1734 	cif->cif_ifp = ifp;
1735 	TAILQ_INIT(&cif->cif_vrs);
1736 
1737 	IF_ADDR_WLOCK(ifp);
1738 	ifp->if_carp = cif;
1739 	if_ref(ifp);
1740 	IF_ADDR_WUNLOCK(ifp);
1741 
1742 	return (cif);
1743 }
1744 
1745 static void
1746 carp_free_if(struct carp_if *cif)
1747 {
1748 	struct ifnet *ifp = cif->cif_ifp;
1749 
1750 	CIF_LOCK_ASSERT(cif);
1751 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1752 	    __func__));
1753 
1754 	IF_ADDR_WLOCK(ifp);
1755 	ifp->if_carp = NULL;
1756 	IF_ADDR_WUNLOCK(ifp);
1757 
1758 	CIF_LOCK_DESTROY(cif);
1759 
1760 	if (cif->cif_flags & CIF_PROMISC)
1761 		ifpromisc(ifp, 0);
1762 	if_rele(ifp);
1763 
1764 	free(cif, M_CARP);
1765 }
1766 
1767 static bool
1768 carp_carprcp(void *arg, struct carp_softc *sc, int priv)
1769 {
1770 	struct carpreq *carpr = arg;
1771 
1772 	CARP_LOCK(sc);
1773 	carpr->carpr_state = sc->sc_state;
1774 	carpr->carpr_vhid = sc->sc_vhid;
1775 	carpr->carpr_advbase = sc->sc_advbase;
1776 	carpr->carpr_advskew = sc->sc_advskew;
1777 	if (priv)
1778 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1779 	else
1780 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1781 	CARP_UNLOCK(sc);
1782 
1783 	return (true);
1784 }
1785 
1786 static int
1787 carp_ioctl_set(if_t ifp, struct carpkreq *carpr)
1788 {
1789 	struct epoch_tracker et;
1790 	struct carp_softc *sc = NULL;
1791 	int error = 0;
1792 
1793 
1794 	if (carpr->carpr_vhid <= 0 || carpr->carpr_vhid > CARP_MAXVHID ||
1795 	    carpr->carpr_advbase < 0 || carpr->carpr_advskew < 0) {
1796 		return (EINVAL);
1797 	}
1798 
1799 	if (ifp->if_carp) {
1800 		IFNET_FOREACH_CARP(ifp, sc)
1801 			if (sc->sc_vhid == carpr->carpr_vhid)
1802 				break;
1803 	}
1804 	if (sc == NULL) {
1805 		sc = carp_alloc(ifp);
1806 		CARP_LOCK(sc);
1807 		sc->sc_vhid = carpr->carpr_vhid;
1808 		LLADDR(&sc->sc_addr)[0] = 0;
1809 		LLADDR(&sc->sc_addr)[1] = 0;
1810 		LLADDR(&sc->sc_addr)[2] = 0x5e;
1811 		LLADDR(&sc->sc_addr)[3] = 0;
1812 		LLADDR(&sc->sc_addr)[4] = 1;
1813 		LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1814 	} else
1815 		CARP_LOCK(sc);
1816 	if (carpr->carpr_advbase > 0) {
1817 		if (carpr->carpr_advbase > 255 ||
1818 		    carpr->carpr_advbase < CARP_DFLTINTV) {
1819 			error = EINVAL;
1820 			goto out;
1821 		}
1822 		sc->sc_advbase = carpr->carpr_advbase;
1823 	}
1824 	if (carpr->carpr_advskew >= 255) {
1825 		error = EINVAL;
1826 		goto out;
1827 	}
1828 	sc->sc_advskew = carpr->carpr_advskew;
1829 	if (carpr->carpr_addr.s_addr != INADDR_ANY)
1830 		sc->sc_carpaddr = carpr->carpr_addr;
1831 	if (! IN6_IS_ADDR_UNSPECIFIED(&carpr->carpr_addr6)) {
1832 		memcpy(&sc->sc_carpaddr6, &carpr->carpr_addr6,
1833 		    sizeof(sc->sc_carpaddr6));
1834 	}
1835 	if (carpr->carpr_key[0] != '\0') {
1836 		bcopy(carpr->carpr_key, sc->sc_key, sizeof(sc->sc_key));
1837 		carp_hmac_prepare(sc);
1838 	}
1839 	if (sc->sc_state != INIT &&
1840 	    carpr->carpr_state != sc->sc_state) {
1841 		switch (carpr->carpr_state) {
1842 		case BACKUP:
1843 			callout_stop(&sc->sc_ad_tmo);
1844 			carp_set_state(sc, BACKUP,
1845 			    "user requested via ifconfig");
1846 			carp_setrun(sc, 0);
1847 			carp_delroute(sc);
1848 			break;
1849 		case MASTER:
1850 			NET_EPOCH_ENTER(et);
1851 			carp_master_down_locked(sc,
1852 			    "user requested via ifconfig");
1853 			NET_EPOCH_EXIT(et);
1854 			break;
1855 		default:
1856 			break;
1857 		}
1858 	}
1859 
1860 out:
1861 	CARP_UNLOCK(sc);
1862 
1863 	return (error);
1864 }
1865 
1866 static int
1867 carp_ioctl_get(if_t ifp, struct ucred *cred, struct carpreq *carpr,
1868     bool (*outfn)(void *, struct carp_softc *, int), void *arg)
1869 {
1870 	int priveleged;
1871 	struct carp_softc *sc;
1872 
1873 	if (carpr->carpr_vhid < 0 || carpr->carpr_vhid > CARP_MAXVHID)
1874 		return (EINVAL);
1875 	if (carpr->carpr_count < 1)
1876 		return (EMSGSIZE);
1877 	if (ifp->if_carp == NULL)
1878 		return (ENOENT);
1879 
1880 	priveleged = (priv_check_cred(cred, PRIV_NETINET_CARP) == 0);
1881 	if (carpr->carpr_vhid != 0) {
1882 		IFNET_FOREACH_CARP(ifp, sc)
1883 			if (sc->sc_vhid == carpr->carpr_vhid)
1884 				break;
1885 		if (sc == NULL)
1886 			return (ENOENT);
1887 
1888 		if (! outfn(arg, sc, priveleged))
1889 			return (ENOMEM);
1890 		carpr->carpr_count = 1;
1891 	} else  {
1892 		int count;
1893 
1894 		count = 0;
1895 		IFNET_FOREACH_CARP(ifp, sc)
1896 			count++;
1897 
1898 		if (count > carpr->carpr_count)
1899 			return (EMSGSIZE);
1900 
1901 		IFNET_FOREACH_CARP(ifp, sc) {
1902 			if (! outfn(arg, sc, priveleged))
1903 				return (ENOMEM);
1904 			carpr->carpr_count = count;
1905 		}
1906 	}
1907 
1908 	return (0);
1909 }
1910 
1911 int
1912 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1913 {
1914 	struct carpreq carpr;
1915 	struct carpkreq carprk = { };
1916 	struct ifnet *ifp;
1917 	int error = 0;
1918 
1919 	if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1920 		return (error);
1921 
1922 	ifp = ifunit_ref(ifr->ifr_name);
1923 	if ((error = carp_is_supported_if(ifp)) != 0)
1924 		goto out;
1925 
1926 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1927 		error = EADDRNOTAVAIL;
1928 		goto out;
1929 	}
1930 
1931 	sx_xlock(&carp_sx);
1932 	switch (cmd) {
1933 	case SIOCSVH:
1934 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1935 			break;
1936 
1937 		memcpy(&carprk, &carpr, sizeof(carpr));
1938 		error = carp_ioctl_set(ifp, &carprk);
1939 		break;
1940 
1941 	case SIOCGVH:
1942 		error = carp_ioctl_get(ifp, td->td_ucred, &carpr,
1943 		    carp_carprcp, &carpr);
1944 		if (error == 0) {
1945 			error = copyout(&carpr,
1946 			    (char *)ifr_data_get_ptr(ifr),
1947 			    carpr.carpr_count * sizeof(carpr));
1948 		}
1949 		break;
1950 	default:
1951 		error = EINVAL;
1952 	}
1953 	sx_xunlock(&carp_sx);
1954 
1955 out:
1956 	if (ifp != NULL)
1957 		if_rele(ifp);
1958 
1959 	return (error);
1960 }
1961 
1962 static int
1963 carp_get_vhid(struct ifaddr *ifa)
1964 {
1965 
1966 	if (ifa == NULL || ifa->ifa_carp == NULL)
1967 		return (0);
1968 
1969 	return (ifa->ifa_carp->sc_vhid);
1970 }
1971 
1972 int
1973 carp_attach(struct ifaddr *ifa, int vhid)
1974 {
1975 	struct ifnet *ifp = ifa->ifa_ifp;
1976 	struct carp_if *cif = ifp->if_carp;
1977 	struct carp_softc *sc;
1978 	int index, error;
1979 
1980 	KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1981 
1982 	switch (ifa->ifa_addr->sa_family) {
1983 #ifdef INET
1984 	case AF_INET:
1985 #endif
1986 #ifdef INET6
1987 	case AF_INET6:
1988 #endif
1989 		break;
1990 	default:
1991 		return (EPROTOTYPE);
1992 	}
1993 
1994 	sx_xlock(&carp_sx);
1995 	if (ifp->if_carp == NULL) {
1996 		sx_xunlock(&carp_sx);
1997 		return (ENOPROTOOPT);
1998 	}
1999 
2000 	IFNET_FOREACH_CARP(ifp, sc)
2001 		if (sc->sc_vhid == vhid)
2002 			break;
2003 	if (sc == NULL) {
2004 		sx_xunlock(&carp_sx);
2005 		return (ENOENT);
2006 	}
2007 
2008 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
2009 	if (error) {
2010 		CIF_FREE(cif);
2011 		sx_xunlock(&carp_sx);
2012 		return (error);
2013 	}
2014 
2015 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
2016 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
2017 		carp_grow_ifas(sc);
2018 
2019 	switch (ifa->ifa_addr->sa_family) {
2020 #ifdef INET
2021 	case AF_INET:
2022 		cif->cif_naddrs++;
2023 		sc->sc_naddrs++;
2024 		break;
2025 #endif
2026 #ifdef INET6
2027 	case AF_INET6:
2028 		cif->cif_naddrs6++;
2029 		sc->sc_naddrs6++;
2030 		break;
2031 #endif
2032 	}
2033 
2034 	ifa_ref(ifa);
2035 
2036 	CARP_LOCK(sc);
2037 	sc->sc_ifas[index - 1] = ifa;
2038 	ifa->ifa_carp = sc;
2039 	carp_hmac_prepare(sc);
2040 	carp_sc_state(sc);
2041 	CARP_UNLOCK(sc);
2042 
2043 	sx_xunlock(&carp_sx);
2044 
2045 	return (0);
2046 }
2047 
2048 void
2049 carp_detach(struct ifaddr *ifa, bool keep_cif)
2050 {
2051 	struct ifnet *ifp = ifa->ifa_ifp;
2052 	struct carp_if *cif = ifp->if_carp;
2053 	struct carp_softc *sc = ifa->ifa_carp;
2054 	int i, index;
2055 
2056 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
2057 
2058 	sx_xlock(&carp_sx);
2059 
2060 	CARP_LOCK(sc);
2061 	/* Shift array. */
2062 	index = sc->sc_naddrs + sc->sc_naddrs6;
2063 	for (i = 0; i < index; i++)
2064 		if (sc->sc_ifas[i] == ifa)
2065 			break;
2066 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
2067 	for (; i < index - 1; i++)
2068 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
2069 	sc->sc_ifas[index - 1] = NULL;
2070 
2071 	switch (ifa->ifa_addr->sa_family) {
2072 #ifdef INET
2073 	case AF_INET:
2074 		cif->cif_naddrs--;
2075 		sc->sc_naddrs--;
2076 		break;
2077 #endif
2078 #ifdef INET6
2079 	case AF_INET6:
2080 		cif->cif_naddrs6--;
2081 		sc->sc_naddrs6--;
2082 		break;
2083 #endif
2084 	}
2085 
2086 	carp_ifa_delroute(ifa);
2087 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
2088 
2089 	ifa->ifa_carp = NULL;
2090 	ifa_free(ifa);
2091 
2092 	carp_hmac_prepare(sc);
2093 	carp_sc_state(sc);
2094 
2095 	if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2096 		carp_destroy(sc);
2097 	else
2098 		CARP_UNLOCK(sc);
2099 
2100 	if (!keep_cif)
2101 		CIF_FREE(cif);
2102 
2103 	sx_xunlock(&carp_sx);
2104 }
2105 
2106 static void
2107 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2108 {
2109 
2110 	CARP_LOCK_ASSERT(sc);
2111 
2112 	if (sc->sc_state != state) {
2113 		const char *carp_states[] = { CARP_STATES };
2114 		char subsys[IFNAMSIZ+5];
2115 
2116 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2117 		    if_name(sc->sc_carpdev));
2118 
2119 		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2120 		    carp_states[sc->sc_state], carp_states[state], reason);
2121 
2122 		sc->sc_state = state;
2123 
2124 		devctl_notify("CARP", subsys, carp_states[state], NULL);
2125 	}
2126 }
2127 
2128 static void
2129 carp_linkstate(struct ifnet *ifp)
2130 {
2131 	struct carp_softc *sc;
2132 
2133 	CIF_LOCK(ifp->if_carp);
2134 	IFNET_FOREACH_CARP(ifp, sc) {
2135 		CARP_LOCK(sc);
2136 		carp_sc_state(sc);
2137 		CARP_UNLOCK(sc);
2138 	}
2139 	CIF_UNLOCK(ifp->if_carp);
2140 }
2141 
2142 static void
2143 carp_sc_state(struct carp_softc *sc)
2144 {
2145 
2146 	CARP_LOCK_ASSERT(sc);
2147 
2148 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2149 	    !(sc->sc_carpdev->if_flags & IFF_UP) ||
2150 	    !V_carp_allow) {
2151 		callout_stop(&sc->sc_ad_tmo);
2152 #ifdef INET
2153 		callout_stop(&sc->sc_md_tmo);
2154 #endif
2155 #ifdef INET6
2156 		callout_stop(&sc->sc_md6_tmo);
2157 #endif
2158 		carp_set_state(sc, INIT, "hardware interface down");
2159 		carp_setrun(sc, 0);
2160 		carp_delroute(sc);
2161 		if (!sc->sc_suppress)
2162 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2163 		sc->sc_suppress = 1;
2164 	} else {
2165 		carp_set_state(sc, INIT, "hardware interface up");
2166 		carp_setrun(sc, 0);
2167 		if (sc->sc_suppress)
2168 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2169 		sc->sc_suppress = 0;
2170 	}
2171 }
2172 
2173 static void
2174 carp_demote_adj(int adj, char *reason)
2175 {
2176 	atomic_add_int(&V_carp_demotion, adj);
2177 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2178 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2179 }
2180 
2181 static int
2182 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2183 {
2184 	int new, error;
2185 	struct carp_softc *sc;
2186 
2187 	new = V_carp_allow;
2188 	error = sysctl_handle_int(oidp, &new, 0, req);
2189 	if (error || !req->newptr)
2190 		return (error);
2191 
2192 	if (V_carp_allow != new) {
2193 		V_carp_allow = new;
2194 
2195 		mtx_lock(&carp_mtx);
2196 		LIST_FOREACH(sc, &carp_list, sc_next) {
2197 			CARP_LOCK(sc);
2198 			if (curvnet == sc->sc_carpdev->if_vnet)
2199 				carp_sc_state(sc);
2200 			CARP_UNLOCK(sc);
2201 		}
2202 		mtx_unlock(&carp_mtx);
2203 	}
2204 
2205 	return (0);
2206 }
2207 
2208 static int
2209 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2210 {
2211 	int new, error;
2212 
2213 	new = V_carp_dscp;
2214 	error = sysctl_handle_int(oidp, &new, 0, req);
2215 	if (error || !req->newptr)
2216 		return (error);
2217 
2218 	if (new < 0 || new > 63)
2219 		return (EINVAL);
2220 
2221 	V_carp_dscp = new;
2222 
2223 	return (0);
2224 }
2225 
2226 static int
2227 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2228 {
2229 	int new, error;
2230 
2231 	new = V_carp_demotion;
2232 	error = sysctl_handle_int(oidp, &new, 0, req);
2233 	if (error || !req->newptr)
2234 		return (error);
2235 
2236 	carp_demote_adj(new, "sysctl");
2237 
2238 	return (0);
2239 }
2240 
2241 static int
2242 nlattr_get_carp_key(struct nlattr *nla, struct nl_pstate *npt, const void *arg, void *target)
2243 {
2244 	if (__predict_false(NLA_DATA_LEN(nla) > CARP_KEY_LEN))
2245 		return (EINVAL);
2246 
2247 	memcpy(target, NLA_DATA_CONST(nla), NLA_DATA_LEN(nla));
2248 	return (0);
2249 }
2250 
2251 struct carp_nl_send_args {
2252 	struct nlmsghdr *hdr;
2253 	struct nl_pstate *npt;
2254 };
2255 
2256 static bool
2257 carp_nl_send(void *arg, struct carp_softc *sc, int priv)
2258 {
2259 	struct carp_nl_send_args *nlsa = arg;
2260 	struct nlmsghdr *hdr = nlsa->hdr;
2261 	struct nl_pstate *npt = nlsa->npt;
2262 	struct nl_writer *nw = npt->nw;
2263 	struct genlmsghdr *ghdr_new;
2264 
2265 	if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) {
2266 		nlmsg_abort(nw);
2267 		return (false);
2268 	}
2269 
2270 	ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
2271 	if (ghdr_new == NULL) {
2272 		nlmsg_abort(nw);
2273 		return (false);
2274 	}
2275 
2276 	ghdr_new->cmd = CARP_NL_CMD_GET;
2277 	ghdr_new->version = 0;
2278 	ghdr_new->reserved = 0;
2279 
2280 	CARP_LOCK(sc);
2281 
2282 	nlattr_add_u32(nw, CARP_NL_VHID, sc->sc_vhid);
2283 	nlattr_add_u32(nw, CARP_NL_STATE, sc->sc_state);
2284 	nlattr_add_s32(nw, CARP_NL_ADVBASE, sc->sc_advbase);
2285 	nlattr_add_s32(nw, CARP_NL_ADVSKEW, sc->sc_advskew);
2286 	nlattr_add_in_addr(nw, CARP_NL_ADDR, &sc->sc_carpaddr);
2287 	nlattr_add_in6_addr(nw, CARP_NL_ADDR6, &sc->sc_carpaddr6);
2288 
2289 	if (priv)
2290 		nlattr_add(nw, CARP_NL_KEY, sizeof(sc->sc_key), sc->sc_key);
2291 
2292 	CARP_UNLOCK(sc);
2293 
2294 	if (! nlmsg_end(nw)) {
2295 		nlmsg_abort(nw);
2296 		return (false);
2297 	}
2298 
2299 	return (true);
2300 }
2301 
2302 struct nl_carp_parsed {
2303 	unsigned int	ifindex;
2304 	char		*ifname;
2305 	uint32_t	state;
2306 	uint32_t	vhid;
2307 	int32_t		advbase;
2308 	int32_t		advskew;
2309 	char		key[CARP_KEY_LEN];
2310 	struct in_addr	addr;
2311 	struct in6_addr	addr6;
2312 };
2313 
2314 #define	_IN(_field)	offsetof(struct genlmsghdr, _field)
2315 #define	_OUT(_field)	offsetof(struct nl_carp_parsed, _field)
2316 
2317 static const struct nlattr_parser nla_p_set[] = {
2318 	{ .type = CARP_NL_VHID, .off = _OUT(vhid), .cb = nlattr_get_uint32 },
2319 	{ .type = CARP_NL_STATE, .off = _OUT(state), .cb = nlattr_get_uint32 },
2320 	{ .type = CARP_NL_ADVBASE, .off = _OUT(advbase), .cb = nlattr_get_uint32 },
2321 	{ .type = CARP_NL_ADVSKEW, .off = _OUT(advskew), .cb = nlattr_get_uint32 },
2322 	{ .type = CARP_NL_KEY, .off = _OUT(key), .cb = nlattr_get_carp_key },
2323 	{ .type = CARP_NL_IFINDEX, .off = _OUT(ifindex), .cb = nlattr_get_uint32 },
2324 	{ .type = CARP_NL_ADDR, .off = _OUT(addr), .cb = nlattr_get_in_addr },
2325 	{ .type = CARP_NL_ADDR6, .off = _OUT(addr6), .cb = nlattr_get_in6_addr },
2326 	{ .type = CARP_NL_IFNAME, .off = _OUT(ifname), .cb = nlattr_get_string },
2327 };
2328 static const struct nlfield_parser nlf_p_set[] = {
2329 };
2330 NL_DECLARE_PARSER(carp_parser, struct genlmsghdr, nlf_p_set, nla_p_set);
2331 #undef _IN
2332 #undef _OUT
2333 
2334 
2335 static int
2336 carp_nl_get(struct nlmsghdr *hdr, struct nl_pstate *npt)
2337 {
2338 	struct nl_carp_parsed attrs = { };
2339 	struct carp_nl_send_args args;
2340 	struct carpreq carpr = { };
2341 	struct epoch_tracker et;
2342 	if_t ifp = NULL;
2343 	int error;
2344 
2345 	error = nl_parse_nlmsg(hdr, &carp_parser, npt, &attrs);
2346 	if (error != 0)
2347 		return (error);
2348 
2349 	NET_EPOCH_ENTER(et);
2350 	if (attrs.ifname != NULL)
2351 		ifp = ifunit_ref(attrs.ifname);
2352 	else if (attrs.ifindex != 0)
2353 		ifp = ifnet_byindex_ref(attrs.ifindex);
2354 	NET_EPOCH_EXIT(et);
2355 
2356 	if ((error = carp_is_supported_if(ifp)) != 0)
2357 		goto out;
2358 
2359 	hdr->nlmsg_flags |= NLM_F_MULTI;
2360 	args.hdr = hdr;
2361 	args.npt = npt;
2362 
2363 	carpr.carpr_vhid = attrs.vhid;
2364 	carpr.carpr_count = CARP_MAXVHID;
2365 
2366 	sx_xlock(&carp_sx);
2367 	error = carp_ioctl_get(ifp, nlp_get_cred(npt->nlp), &carpr,
2368 	    carp_nl_send, &args);
2369 	sx_xunlock(&carp_sx);
2370 
2371 	if (! nlmsg_end_dump(npt->nw, error, hdr))
2372 		error = ENOMEM;
2373 
2374 out:
2375 	if (ifp != NULL)
2376 		if_rele(ifp);
2377 
2378 	return (error);
2379 }
2380 
2381 static int
2382 carp_nl_set(struct nlmsghdr *hdr, struct nl_pstate *npt)
2383 {
2384 	struct nl_carp_parsed attrs = { };
2385 	struct carpkreq carpr;
2386 	struct epoch_tracker et;
2387 	if_t ifp = NULL;
2388 	int error;
2389 
2390 	error = nl_parse_nlmsg(hdr, &carp_parser, npt, &attrs);
2391 	if (error != 0)
2392 		return (error);
2393 
2394 	if (attrs.vhid <= 0 || attrs.vhid > CARP_MAXVHID)
2395 		return (EINVAL);
2396 	if (attrs.state > CARP_MAXSTATE)
2397 		return (EINVAL);
2398 	if (attrs.advbase < 0 || attrs.advskew < 0)
2399 		return (EINVAL);
2400 	if (attrs.advbase > 255)
2401 		return (EINVAL);
2402 	if (attrs.advskew >= 255)
2403 		return (EINVAL);
2404 
2405 	NET_EPOCH_ENTER(et);
2406 	if (attrs.ifname != NULL)
2407 		ifp = ifunit_ref(attrs.ifname);
2408 	else if (attrs.ifindex != 0)
2409 		ifp = ifnet_byindex_ref(attrs.ifindex);
2410 	NET_EPOCH_EXIT(et);
2411 
2412 	if ((error = carp_is_supported_if(ifp)) != 0)
2413 		goto out;
2414 
2415 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
2416 		error = EADDRNOTAVAIL;
2417 		goto out;
2418 	}
2419 
2420 	carpr.carpr_count = 1;
2421 	carpr.carpr_vhid = attrs.vhid;
2422 	carpr.carpr_state = attrs.state;
2423 	carpr.carpr_advbase = attrs.advbase;
2424 	carpr.carpr_advskew = attrs.advskew;
2425 	carpr.carpr_addr = attrs.addr;
2426 	carpr.carpr_addr6 = attrs.addr6;
2427 
2428 	memcpy(&carpr.carpr_key, &attrs.key, sizeof(attrs.key));
2429 
2430 	sx_xlock(&carp_sx);
2431 	error = carp_ioctl_set(ifp, &carpr);
2432 	sx_xunlock(&carp_sx);
2433 
2434 out:
2435 	if (ifp != NULL)
2436 		if_rele(ifp);
2437 
2438 	return (error);
2439 }
2440 
2441 static const struct nlhdr_parser *all_parsers[] = {
2442 	&carp_parser
2443 };
2444 
2445 static const struct genl_cmd carp_cmds[] = {
2446 	{
2447 		.cmd_num = CARP_NL_CMD_GET,
2448 		.cmd_name = "SIOCGVH",
2449 		.cmd_cb = carp_nl_get,
2450 		.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP |
2451 		    GENL_CMD_CAP_HASPOL,
2452 	},
2453 	{
2454 		.cmd_num = CARP_NL_CMD_SET,
2455 		.cmd_name = "SIOCSVH",
2456 		.cmd_cb = carp_nl_set,
2457 		.cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_HASPOL,
2458 		.cmd_priv = PRIV_NETINET_CARP,
2459 	},
2460 };
2461 
2462 static void
2463 carp_nl_register(void)
2464 {
2465 	bool ret __diagused;
2466 	int family_id __diagused;
2467 
2468 	NL_VERIFY_PARSERS(all_parsers);
2469 	family_id = genl_register_family(CARP_NL_FAMILY_NAME, 0, 2,
2470 	    CARP_NL_CMD_MAX);
2471 	MPASS(family_id != 0);
2472 
2473 	ret = genl_register_cmds(CARP_NL_FAMILY_NAME, carp_cmds,
2474 	    NL_ARRAY_LEN(carp_cmds));
2475 	MPASS(ret);
2476 }
2477 
2478 static void
2479 carp_nl_unregister(void)
2480 {
2481 	genl_unregister_family(CARP_NL_FAMILY_NAME);
2482 }
2483 
2484 static void
2485 carp_mod_cleanup(void)
2486 {
2487 
2488 	carp_nl_unregister();
2489 
2490 #ifdef INET
2491 	(void)ipproto_unregister(IPPROTO_CARP);
2492 	carp_iamatch_p = NULL;
2493 #endif
2494 #ifdef INET6
2495 	(void)ip6proto_unregister(IPPROTO_CARP);
2496 	carp_iamatch6_p = NULL;
2497 	carp_macmatch6_p = NULL;
2498 #endif
2499 	carp_ioctl_p = NULL;
2500 	carp_attach_p = NULL;
2501 	carp_detach_p = NULL;
2502 	carp_get_vhid_p = NULL;
2503 	carp_linkstate_p = NULL;
2504 	carp_forus_p = NULL;
2505 	carp_output_p = NULL;
2506 	carp_demote_adj_p = NULL;
2507 	carp_master_p = NULL;
2508 	mtx_unlock(&carp_mtx);
2509 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2510 	mtx_destroy(&carp_mtx);
2511 	sx_destroy(&carp_sx);
2512 }
2513 
2514 static void
2515 ipcarp_sysinit(void)
2516 {
2517 
2518 	/* Load allow as tunable so to postpone carp start after module load */
2519 	TUNABLE_INT_FETCH("net.inet.carp.allow", &V_carp_allow);
2520 }
2521 VNET_SYSINIT(ip_carp, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY, ipcarp_sysinit, NULL);
2522 
2523 static int
2524 carp_mod_load(void)
2525 {
2526 	int err;
2527 
2528 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2529 	sx_init(&carp_sx, "carp_sx");
2530 	LIST_INIT(&carp_list);
2531 	carp_get_vhid_p = carp_get_vhid;
2532 	carp_forus_p = carp_forus;
2533 	carp_output_p = carp_output;
2534 	carp_linkstate_p = carp_linkstate;
2535 	carp_ioctl_p = carp_ioctl;
2536 	carp_attach_p = carp_attach;
2537 	carp_detach_p = carp_detach;
2538 	carp_demote_adj_p = carp_demote_adj;
2539 	carp_master_p = carp_master;
2540 #ifdef INET6
2541 	carp_iamatch6_p = carp_iamatch6;
2542 	carp_macmatch6_p = carp_macmatch6;
2543 	err = ip6proto_register(IPPROTO_CARP, carp6_input, NULL);
2544 	if (err) {
2545 		printf("carp: error %d registering with INET6\n", err);
2546 		carp_mod_cleanup();
2547 		return (err);
2548 	}
2549 #endif
2550 #ifdef INET
2551 	carp_iamatch_p = carp_iamatch;
2552 	err = ipproto_register(IPPROTO_CARP, carp_input, NULL);
2553 	if (err) {
2554 		printf("carp: error %d registering with INET\n", err);
2555 		carp_mod_cleanup();
2556 		return (err);
2557 	}
2558 #endif
2559 
2560 	carp_nl_register();
2561 
2562 	return (0);
2563 }
2564 
2565 static int
2566 carp_modevent(module_t mod, int type, void *data)
2567 {
2568 	switch (type) {
2569 	case MOD_LOAD:
2570 		return carp_mod_load();
2571 		/* NOTREACHED */
2572 	case MOD_UNLOAD:
2573 		mtx_lock(&carp_mtx);
2574 		if (LIST_EMPTY(&carp_list))
2575 			carp_mod_cleanup();
2576 		else {
2577 			mtx_unlock(&carp_mtx);
2578 			return (EBUSY);
2579 		}
2580 		break;
2581 
2582 	default:
2583 		return (EINVAL);
2584 	}
2585 
2586 	return (0);
2587 }
2588 
2589 static moduledata_t carp_mod = {
2590 	"carp",
2591 	carp_modevent,
2592 	0
2593 };
2594 
2595 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2596