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/protosw.h>
50#include <sys/socket.h>
51#include <sys/sockio.h>
52#include <sys/sysctl.h>
53#include <sys/syslog.h>
54#include <sys/taskqueue.h>
55#include <sys/counter.h>
56
57#include <net/ethernet.h>
58#include <net/if.h>
59#include <net/if_var.h>
60#include <net/if_dl.h>
61#include <net/if_llatbl.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.h>
71#include <machine/in_cksum.h>
72#endif
73#ifdef INET
74#include <netinet/ip_var.h>
75#include <netinet/if_ether.h>
76#endif
77
78#ifdef INET6
79#include <netinet/icmp6.h>
80#include <netinet/ip6.h>
81#include <netinet6/in6_var.h>
82#include <netinet6/ip6_var.h>
83#include <netinet6/scope6_var.h>
84#include <netinet6/nd6.h>
85#endif
86
87#include <crypto/sha1.h>
88
89static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
90
91struct carp_softc {
92	struct ifnet		*sc_carpdev;	/* Pointer to parent ifnet. */
93	struct ifaddr		**sc_ifas;	/* Our ifaddrs. */
94	struct sockaddr_dl	sc_addr;	/* Our link level address. */
95	struct callout		sc_ad_tmo;	/* Advertising timeout. */
96#ifdef INET
97	struct callout		sc_md_tmo;	/* Master down timeout. */
98#endif
99#ifdef INET6
100	struct callout 		sc_md6_tmo;	/* XXX: Master down timeout. */
101#endif
102	struct mtx		sc_mtx;
103
104	int			sc_vhid;
105	int			sc_advskew;
106	int			sc_advbase;
107
108	int			sc_naddrs;
109	int			sc_naddrs6;
110	int			sc_ifasiz;
111	enum { INIT = 0, BACKUP, MASTER }	sc_state;
112	int			sc_suppress;
113	int			sc_sendad_errors;
114#define	CARP_SENDAD_MAX_ERRORS	3
115	int			sc_sendad_success;
116#define	CARP_SENDAD_MIN_SUCCESS 3
117
118	int			sc_init_counter;
119	uint64_t		sc_counter;
120
121	/* authentication */
122#define	CARP_HMAC_PAD	64
123	unsigned char sc_key[CARP_KEY_LEN];
124	unsigned char sc_pad[CARP_HMAC_PAD];
125	SHA1_CTX sc_sha1;
126
127	TAILQ_ENTRY(carp_softc)	sc_list;	/* On the carp_if list. */
128	LIST_ENTRY(carp_softc)	sc_next;	/* On the global list. */
129};
130
131struct carp_if {
132#ifdef INET
133	int	cif_naddrs;
134#endif
135#ifdef INET6
136	int	cif_naddrs6;
137#endif
138	TAILQ_HEAD(, carp_softc) cif_vrs;
139#ifdef INET
140	struct ip_moptions 	 cif_imo;
141#endif
142#ifdef INET6
143	struct ip6_moptions 	 cif_im6o;
144#endif
145	struct ifnet	*cif_ifp;
146	struct mtx	cif_mtx;
147	uint32_t	cif_flags;
148#define	CIF_PROMISC	0x00000001
149};
150
151#define	CARP_INET	0
152#define	CARP_INET6	1
153static int proto_reg[] = {-1, -1};
154
155/*
156 * Brief design of carp(4).
157 *
158 * Any carp-capable ifnet may have a list of carp softcs hanging off
159 * its ifp->if_carp pointer. Each softc represents one unique virtual
160 * host id, or vhid. The softc has a back pointer to the ifnet. All
161 * softcs are joined in a global list, which has quite limited use.
162 *
163 * Any interface address that takes part in CARP negotiation has a
164 * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
165 * AF_INET or AF_INET6 address.
166 *
167 * Although, one can get the softc's backpointer to ifnet and traverse
168 * through its ifp->if_addrhead queue to find all interface addresses
169 * involved in CARP, we keep a growable array of ifaddr pointers. This
170 * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
171 * do calls into the network stack, thus avoiding LORs.
172 *
173 * Locking:
174 *
175 * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
176 * callout-driven events and ioctl()s.
177 *
178 * To traverse the list of softcs on an ifnet we use CIF_LOCK() or carp_sx.
179 * To traverse the global list we use the mutex carp_mtx.
180 *
181 * Known issues with locking:
182 *
183 * - Sending ad, we put the pointer to the softc in an mtag, and no reference
184 *   counting is done on the softc.
185 * - On module unload we may race (?) with packet processing thread
186 *   dereferencing our function pointers.
187 */
188
189/* Accept incoming CARP packets. */
190VNET_DEFINE_STATIC(int, carp_allow) = 1;
191#define	V_carp_allow	VNET(carp_allow)
192
193/* Set DSCP in outgoing CARP packets. */
194VNET_DEFINE_STATIC(int, carp_dscp) = 56;
195#define	V_carp_dscp	VNET(carp_dscp)
196
197/* Preempt slower nodes. */
198VNET_DEFINE_STATIC(int, carp_preempt) = 0;
199#define	V_carp_preempt	VNET(carp_preempt)
200
201/* Log level. */
202VNET_DEFINE_STATIC(int, carp_log) = 1;
203#define	V_carp_log	VNET(carp_log)
204
205/* Global advskew demotion. */
206VNET_DEFINE_STATIC(int, carp_demotion) = 0;
207#define	V_carp_demotion	VNET(carp_demotion)
208
209/* Send error demotion factor. */
210VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
211#define	V_carp_senderr_adj	VNET(carp_senderr_adj)
212
213/* Iface down demotion factor. */
214VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
215#define	V_carp_ifdown_adj	VNET(carp_ifdown_adj)
216
217static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
218static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
219static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
220
221SYSCTL_NODE(_net_inet, IPPROTO_CARP, carp, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
222    "CARP");
223SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
224    CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
225    0, 0, carp_allow_sysctl, "I",
226    "Accept incoming CARP packets");
227SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
228    CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
229    0, 0, carp_dscp_sysctl, "I",
230    "DSCP value for carp packets");
231SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
232    &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
233SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
234    &VNET_NAME(carp_log), 0, "CARP log level");
235SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
236    CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
237    0, 0, carp_demote_adj_sysctl, "I",
238    "Adjust demotion factor (skew of advskew)");
239SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
240    CTLFLAG_VNET | CTLFLAG_RW,
241    &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
242SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
243    CTLFLAG_VNET | CTLFLAG_RW,
244    &VNET_NAME(carp_ifdown_adj), 0,
245    "Interface down demotion factor adjustment");
246
247VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
248VNET_PCPUSTAT_SYSINIT(carpstats);
249VNET_PCPUSTAT_SYSUNINIT(carpstats);
250
251#define	CARPSTATS_ADD(name, val)	\
252    counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
253	sizeof(uint64_t)], (val))
254#define	CARPSTATS_INC(name)		CARPSTATS_ADD(name, 1)
255
256SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
257    carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
258
259#define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
260	NULL, MTX_DEF)
261#define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
262#define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
263#define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
264#define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
265#define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
266	NULL, MTX_DEF)
267#define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
268#define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
269#define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
270#define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
271#define	CIF_FREE(cif)	do {				\
272		CIF_LOCK(cif);				\
273		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
274			carp_free_if(cif);		\
275		else					\
276			CIF_UNLOCK(cif);		\
277} while (0)
278
279#define	CARP_LOG(...)	do {				\
280	if (V_carp_log > 0)				\
281		log(LOG_INFO, "carp: " __VA_ARGS__);	\
282} while (0)
283
284#define	CARP_DEBUG(...)	do {				\
285	if (V_carp_log > 1)				\
286		log(LOG_DEBUG, __VA_ARGS__);		\
287} while (0)
288
289#define	IFNET_FOREACH_IFA(ifp, ifa)					\
290	CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)	\
291		if ((ifa)->ifa_carp != NULL)
292
293#define	CARP_FOREACH_IFA(sc, ifa)					\
294	CARP_LOCK_ASSERT(sc);						\
295	for (int _i = 0;						\
296		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
297		((ifa) = sc->sc_ifas[_i]) != NULL;			\
298		++_i)
299
300#define	IFNET_FOREACH_CARP(ifp, sc)					\
301	KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) ||			\
302	    sx_xlocked(&carp_sx), ("cif_vrs not locked"));		\
303	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
304
305#define	DEMOTE_ADVSKEW(sc)					\
306    (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?	\
307    CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion))
308
309static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
310static struct carp_softc
311		*carp_alloc(struct ifnet *);
312static void	carp_destroy(struct carp_softc *);
313static struct carp_if
314		*carp_alloc_if(struct ifnet *);
315static void	carp_free_if(struct carp_if *);
316static void	carp_set_state(struct carp_softc *, int, const char* reason);
317static void	carp_sc_state(struct carp_softc *);
318static void	carp_setrun(struct carp_softc *, sa_family_t);
319static void	carp_master_down(void *);
320static void	carp_master_down_locked(struct carp_softc *,
321    		    const char* reason);
322static void	carp_send_ad(void *);
323static void	carp_send_ad_locked(struct carp_softc *);
324static void	carp_addroute(struct carp_softc *);
325static void	carp_ifa_addroute(struct ifaddr *);
326static void	carp_delroute(struct carp_softc *);
327static void	carp_ifa_delroute(struct ifaddr *);
328static void	carp_send_ad_all(void *, int);
329static void	carp_demote_adj(int, char *);
330
331static LIST_HEAD(, carp_softc) carp_list;
332static struct mtx carp_mtx;
333static struct sx carp_sx;
334static struct task carp_sendall_task =
335    TASK_INITIALIZER(0, carp_send_ad_all, NULL);
336
337static void
338carp_hmac_prepare(struct carp_softc *sc)
339{
340	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
341	uint8_t vhid = sc->sc_vhid & 0xff;
342	struct ifaddr *ifa;
343	int i, found;
344#ifdef INET
345	struct in_addr last, cur, in;
346#endif
347#ifdef INET6
348	struct in6_addr last6, cur6, in6;
349#endif
350
351	CARP_LOCK_ASSERT(sc);
352
353	/* Compute ipad from key. */
354	bzero(sc->sc_pad, sizeof(sc->sc_pad));
355	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
356	for (i = 0; i < sizeof(sc->sc_pad); i++)
357		sc->sc_pad[i] ^= 0x36;
358
359	/* Precompute first part of inner hash. */
360	SHA1Init(&sc->sc_sha1);
361	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
362	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
363	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
364	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
365#ifdef INET
366	cur.s_addr = 0;
367	do {
368		found = 0;
369		last = cur;
370		cur.s_addr = 0xffffffff;
371		CARP_FOREACH_IFA(sc, ifa) {
372			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
373			if (ifa->ifa_addr->sa_family == AF_INET &&
374			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
375			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
376				cur.s_addr = in.s_addr;
377				found++;
378			}
379		}
380		if (found)
381			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
382	} while (found);
383#endif /* INET */
384#ifdef INET6
385	memset(&cur6, 0, sizeof(cur6));
386	do {
387		found = 0;
388		last6 = cur6;
389		memset(&cur6, 0xff, sizeof(cur6));
390		CARP_FOREACH_IFA(sc, ifa) {
391			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
392			if (IN6_IS_SCOPE_EMBED(&in6))
393				in6.s6_addr16[1] = 0;
394			if (ifa->ifa_addr->sa_family == AF_INET6 &&
395			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
396			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
397				cur6 = in6;
398				found++;
399			}
400		}
401		if (found)
402			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
403	} while (found);
404#endif /* INET6 */
405
406	/* convert ipad to opad */
407	for (i = 0; i < sizeof(sc->sc_pad); i++)
408		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
409}
410
411static void
412carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
413    unsigned char md[20])
414{
415	SHA1_CTX sha1ctx;
416
417	CARP_LOCK_ASSERT(sc);
418
419	/* fetch first half of inner hash */
420	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
421
422	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
423	SHA1Final(md, &sha1ctx);
424
425	/* outer hash */
426	SHA1Init(&sha1ctx);
427	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
428	SHA1Update(&sha1ctx, md, 20);
429	SHA1Final(md, &sha1ctx);
430}
431
432static int
433carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
434    unsigned char md[20])
435{
436	unsigned char md2[20];
437
438	CARP_LOCK_ASSERT(sc);
439
440	carp_hmac_generate(sc, counter, md2);
441
442	return (bcmp(md, md2, sizeof(md2)));
443}
444
445/*
446 * process input packet.
447 * we have rearranged checks order compared to the rfc,
448 * but it seems more efficient this way or not possible otherwise.
449 */
450#ifdef INET
451int
452carp_input(struct mbuf **mp, int *offp, int proto)
453{
454	struct mbuf *m = *mp;
455	struct ip *ip = mtod(m, struct ip *);
456	struct carp_header *ch;
457	int iplen, len;
458
459	iplen = *offp;
460	*mp = NULL;
461
462	CARPSTATS_INC(carps_ipackets);
463
464	if (!V_carp_allow) {
465		m_freem(m);
466		return (IPPROTO_DONE);
467	}
468
469	/* verify that the IP TTL is 255.  */
470	if (ip->ip_ttl != CARP_DFLTTL) {
471		CARPSTATS_INC(carps_badttl);
472		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
473		    ip->ip_ttl,
474		    m->m_pkthdr.rcvif->if_xname);
475		m_freem(m);
476		return (IPPROTO_DONE);
477	}
478
479	iplen = ip->ip_hl << 2;
480
481	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
482		CARPSTATS_INC(carps_badlen);
483		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
484		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
485		    m->m_pkthdr.rcvif->if_xname);
486		m_freem(m);
487		return (IPPROTO_DONE);
488	}
489
490	if (iplen + sizeof(*ch) < m->m_len) {
491		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
492			CARPSTATS_INC(carps_hdrops);
493			CARP_DEBUG("%s: pullup failed\n", __func__);
494			return (IPPROTO_DONE);
495		}
496		ip = mtod(m, struct ip *);
497	}
498	ch = (struct carp_header *)((char *)ip + iplen);
499
500	/*
501	 * verify that the received packet length is
502	 * equal to the CARP header
503	 */
504	len = iplen + sizeof(*ch);
505	if (len > m->m_pkthdr.len) {
506		CARPSTATS_INC(carps_badlen);
507		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
508		    m->m_pkthdr.len,
509		    m->m_pkthdr.rcvif->if_xname);
510		m_freem(m);
511		return (IPPROTO_DONE);
512	}
513
514	if ((m = m_pullup(m, len)) == NULL) {
515		CARPSTATS_INC(carps_hdrops);
516		return (IPPROTO_DONE);
517	}
518	ip = mtod(m, struct ip *);
519	ch = (struct carp_header *)((char *)ip + iplen);
520
521	/* verify the CARP checksum */
522	m->m_data += iplen;
523	if (in_cksum(m, len - iplen)) {
524		CARPSTATS_INC(carps_badsum);
525		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
526		    m->m_pkthdr.rcvif->if_xname);
527		m_freem(m);
528		return (IPPROTO_DONE);
529	}
530	m->m_data -= iplen;
531
532	carp_input_c(m, ch, AF_INET);
533	return (IPPROTO_DONE);
534}
535#endif
536
537#ifdef INET6
538int
539carp6_input(struct mbuf **mp, int *offp, int proto)
540{
541	struct mbuf *m = *mp;
542	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
543	struct carp_header *ch;
544	u_int len;
545
546	CARPSTATS_INC(carps_ipackets6);
547
548	if (!V_carp_allow) {
549		m_freem(m);
550		return (IPPROTO_DONE);
551	}
552
553	/* check if received on a valid carp interface */
554	if (m->m_pkthdr.rcvif->if_carp == NULL) {
555		CARPSTATS_INC(carps_badif);
556		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
557		    __func__, m->m_pkthdr.rcvif->if_xname);
558		m_freem(m);
559		return (IPPROTO_DONE);
560	}
561
562	/* verify that the IP TTL is 255 */
563	if (ip6->ip6_hlim != CARP_DFLTTL) {
564		CARPSTATS_INC(carps_badttl);
565		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
566		    ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
567		m_freem(m);
568		return (IPPROTO_DONE);
569	}
570
571	/* verify that we have a complete carp packet */
572	if (m->m_len < *offp + sizeof(*ch)) {
573		len = m->m_len;
574		m = m_pullup(m, *offp + sizeof(*ch));
575		if (m == NULL) {
576			CARPSTATS_INC(carps_badlen);
577			CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
578			return (IPPROTO_DONE);
579		}
580	}
581	ch = (struct carp_header *)(mtod(m, char *) + *offp);
582
583	/* verify the CARP checksum */
584	m->m_data += *offp;
585	if (in_cksum(m, sizeof(*ch))) {
586		CARPSTATS_INC(carps_badsum);
587		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
588		    m->m_pkthdr.rcvif->if_xname);
589		m_freem(m);
590		return (IPPROTO_DONE);
591	}
592	m->m_data -= *offp;
593
594	carp_input_c(m, ch, AF_INET6);
595	return (IPPROTO_DONE);
596}
597#endif /* INET6 */
598
599/*
600 * This routine should not be necessary at all, but some switches
601 * (VMWare ESX vswitches) can echo our own packets back at us,
602 * and we must ignore them or they will cause us to drop out of
603 * MASTER mode.
604 *
605 * We cannot catch all cases of network loops.  Instead, what we
606 * do here is catch any packet that arrives with a carp header
607 * with a VHID of 0, that comes from an address that is our own.
608 * These packets are by definition "from us" (even if they are from
609 * a misconfigured host that is pretending to be us).
610 *
611 * The VHID test is outside this mini-function.
612 */
613static int
614carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
615{
616#ifdef INET
617	struct ip *ip4;
618	struct in_addr in4;
619#endif
620#ifdef INET6
621	struct ip6_hdr *ip6;
622	struct in6_addr in6;
623#endif
624
625	switch (af) {
626#ifdef INET
627	case AF_INET:
628		ip4 = mtod(m, struct ip *);
629		in4 = ifatoia(ifa)->ia_addr.sin_addr;
630		return (in4.s_addr == ip4->ip_src.s_addr);
631#endif
632#ifdef INET6
633	case AF_INET6:
634		ip6 = mtod(m, struct ip6_hdr *);
635		in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
636		return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
637#endif
638	default:
639		break;
640	}
641	return (0);
642}
643
644static void
645carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
646{
647	struct ifnet *ifp = m->m_pkthdr.rcvif;
648	struct ifaddr *ifa, *match;
649	struct carp_softc *sc;
650	uint64_t tmp_counter;
651	struct timeval sc_tv, ch_tv;
652	int error;
653
654	NET_EPOCH_ASSERT();
655
656	/*
657	 * Verify that the VHID is valid on the receiving interface.
658	 *
659	 * There should be just one match.  If there are none
660	 * the VHID is not valid and we drop the packet.  If
661	 * there are multiple VHID matches, take just the first
662	 * one, for compatibility with previous code.  While we're
663	 * scanning, check for obvious loops in the network topology
664	 * (these should never happen, and as noted above, we may
665	 * miss real loops; this is just a double-check).
666	 */
667	error = 0;
668	match = NULL;
669	IFNET_FOREACH_IFA(ifp, ifa) {
670		if (match == NULL && ifa->ifa_carp != NULL &&
671		    ifa->ifa_addr->sa_family == af &&
672		    ifa->ifa_carp->sc_vhid == ch->carp_vhid)
673			match = ifa;
674		if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
675			error = ELOOP;
676	}
677	ifa = error ? NULL : match;
678	if (ifa != NULL)
679		ifa_ref(ifa);
680
681	if (ifa == NULL) {
682		if (error == ELOOP) {
683			CARP_DEBUG("dropping looped packet on interface %s\n",
684			    ifp->if_xname);
685			CARPSTATS_INC(carps_badif);	/* ??? */
686		} else {
687			CARPSTATS_INC(carps_badvhid);
688		}
689		m_freem(m);
690		return;
691	}
692
693	/* verify the CARP version. */
694	if (ch->carp_version != CARP_VERSION) {
695		CARPSTATS_INC(carps_badver);
696		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
697		    ch->carp_version);
698		ifa_free(ifa);
699		m_freem(m);
700		return;
701	}
702
703	sc = ifa->ifa_carp;
704	CARP_LOCK(sc);
705	ifa_free(ifa);
706
707	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
708		CARPSTATS_INC(carps_badauth);
709		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
710		    sc->sc_vhid, ifp->if_xname);
711		goto out;
712	}
713
714	tmp_counter = ntohl(ch->carp_counter[0]);
715	tmp_counter = tmp_counter<<32;
716	tmp_counter += ntohl(ch->carp_counter[1]);
717
718	/* XXX Replay protection goes here */
719
720	sc->sc_init_counter = 0;
721	sc->sc_counter = tmp_counter;
722
723	sc_tv.tv_sec = sc->sc_advbase;
724	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
725	ch_tv.tv_sec = ch->carp_advbase;
726	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
727
728	switch (sc->sc_state) {
729	case INIT:
730		break;
731	case MASTER:
732		/*
733		 * If we receive an advertisement from a master who's going to
734		 * be more frequent than us, go into BACKUP state.
735		 */
736		if (timevalcmp(&sc_tv, &ch_tv, >) ||
737		    timevalcmp(&sc_tv, &ch_tv, ==)) {
738			callout_stop(&sc->sc_ad_tmo);
739			carp_set_state(sc, BACKUP,
740			    "more frequent advertisement received");
741			carp_setrun(sc, 0);
742			carp_delroute(sc);
743		}
744		break;
745	case BACKUP:
746		/*
747		 * If we're pre-empting masters who advertise slower than us,
748		 * and this one claims to be slower, treat him as down.
749		 */
750		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
751			carp_master_down_locked(sc,
752			    "preempting a slower master");
753			break;
754		}
755
756		/*
757		 *  If the master is going to advertise at such a low frequency
758		 *  that he's guaranteed to time out, we'd might as well just
759		 *  treat him as timed out now.
760		 */
761		sc_tv.tv_sec = sc->sc_advbase * 3;
762		if (timevalcmp(&sc_tv, &ch_tv, <)) {
763			carp_master_down_locked(sc, "master will time out");
764			break;
765		}
766
767		/*
768		 * Otherwise, we reset the counter and wait for the next
769		 * advertisement.
770		 */
771		carp_setrun(sc, af);
772		break;
773	}
774
775out:
776	CARP_UNLOCK(sc);
777	m_freem(m);
778}
779
780static int
781carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
782{
783	struct m_tag *mtag;
784
785	if (sc->sc_init_counter) {
786		/* this could also be seconds since unix epoch */
787		sc->sc_counter = arc4random();
788		sc->sc_counter = sc->sc_counter << 32;
789		sc->sc_counter += arc4random();
790	} else
791		sc->sc_counter++;
792
793	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
794	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
795
796	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
797
798	/* Tag packet for carp_output */
799	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
800	    M_NOWAIT)) == NULL) {
801		m_freem(m);
802		CARPSTATS_INC(carps_onomem);
803		return (ENOMEM);
804	}
805	bcopy(&sc, mtag + 1, sizeof(sc));
806	m_tag_prepend(m, mtag);
807
808	return (0);
809}
810
811/*
812 * To avoid LORs and possible recursions this function shouldn't
813 * be called directly, but scheduled via taskqueue.
814 */
815static void
816carp_send_ad_all(void *ctx __unused, int pending __unused)
817{
818	struct carp_softc *sc;
819	struct epoch_tracker et;
820
821	NET_EPOCH_ENTER(et);
822	mtx_lock(&carp_mtx);
823	LIST_FOREACH(sc, &carp_list, sc_next)
824		if (sc->sc_state == MASTER) {
825			CARP_LOCK(sc);
826			CURVNET_SET(sc->sc_carpdev->if_vnet);
827			carp_send_ad_locked(sc);
828			CURVNET_RESTORE();
829			CARP_UNLOCK(sc);
830		}
831	mtx_unlock(&carp_mtx);
832	NET_EPOCH_EXIT(et);
833}
834
835/* Send a periodic advertisement, executed in callout context. */
836static void
837carp_send_ad(void *v)
838{
839	struct carp_softc *sc = v;
840	struct epoch_tracker et;
841
842	NET_EPOCH_ENTER(et);
843	CARP_LOCK_ASSERT(sc);
844	CURVNET_SET(sc->sc_carpdev->if_vnet);
845	carp_send_ad_locked(sc);
846	CURVNET_RESTORE();
847	CARP_UNLOCK(sc);
848	NET_EPOCH_EXIT(et);
849}
850
851static void
852carp_send_ad_error(struct carp_softc *sc, int error)
853{
854
855	if (error) {
856		if (sc->sc_sendad_errors < INT_MAX)
857			sc->sc_sendad_errors++;
858		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
859			static const char fmt[] = "send error %d on %s";
860			char msg[sizeof(fmt) + IFNAMSIZ];
861
862			sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
863			carp_demote_adj(V_carp_senderr_adj, msg);
864		}
865		sc->sc_sendad_success = 0;
866	} else {
867		if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
868		    ++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
869			static const char fmt[] = "send ok on %s";
870			char msg[sizeof(fmt) + IFNAMSIZ];
871
872			sprintf(msg, fmt, sc->sc_carpdev->if_xname);
873			carp_demote_adj(-V_carp_senderr_adj, msg);
874			sc->sc_sendad_errors = 0;
875		} else
876			sc->sc_sendad_errors = 0;
877	}
878}
879
880/*
881 * Pick the best ifaddr on the given ifp for sending CARP
882 * advertisements.
883 *
884 * "Best" here is defined by ifa_preferred().  This function is much
885 * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
886 *
887 * (This could be simplified to return the actual address, except that
888 * it has a different format in AF_INET and AF_INET6.)
889 */
890static struct ifaddr *
891carp_best_ifa(int af, struct ifnet *ifp)
892{
893	struct ifaddr *ifa, *best;
894
895	NET_EPOCH_ASSERT();
896
897	if (af >= AF_MAX)
898		return (NULL);
899	best = NULL;
900	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
901		if (ifa->ifa_addr->sa_family == af &&
902		    (best == NULL || ifa_preferred(best, ifa)))
903			best = ifa;
904	}
905	if (best != NULL)
906		ifa_ref(best);
907	return (best);
908}
909
910static void
911carp_send_ad_locked(struct carp_softc *sc)
912{
913	struct carp_header ch;
914	struct timeval tv;
915	struct ifaddr *ifa;
916	struct carp_header *ch_ptr;
917	struct mbuf *m;
918	int len, advskew;
919
920	NET_EPOCH_ASSERT();
921	CARP_LOCK_ASSERT(sc);
922
923	advskew = DEMOTE_ADVSKEW(sc);
924	tv.tv_sec = sc->sc_advbase;
925	tv.tv_usec = advskew * 1000000 / 256;
926
927	ch.carp_version = CARP_VERSION;
928	ch.carp_type = CARP_ADVERTISEMENT;
929	ch.carp_vhid = sc->sc_vhid;
930	ch.carp_advbase = sc->sc_advbase;
931	ch.carp_advskew = advskew;
932	ch.carp_authlen = 7;	/* XXX DEFINE */
933	ch.carp_pad1 = 0;	/* must be zero */
934	ch.carp_cksum = 0;
935
936	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
937
938#ifdef INET
939	if (sc->sc_naddrs) {
940		struct ip *ip;
941
942		m = m_gethdr(M_NOWAIT, MT_DATA);
943		if (m == NULL) {
944			CARPSTATS_INC(carps_onomem);
945			goto resched;
946		}
947		len = sizeof(*ip) + sizeof(ch);
948		m->m_pkthdr.len = len;
949		m->m_pkthdr.rcvif = NULL;
950		m->m_len = len;
951		M_ALIGN(m, m->m_len);
952		m->m_flags |= M_MCAST;
953		ip = mtod(m, struct ip *);
954		ip->ip_v = IPVERSION;
955		ip->ip_hl = sizeof(*ip) >> 2;
956		ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
957		ip->ip_len = htons(len);
958		ip->ip_off = htons(IP_DF);
959		ip->ip_ttl = CARP_DFLTTL;
960		ip->ip_p = IPPROTO_CARP;
961		ip->ip_sum = 0;
962		ip_fillid(ip);
963
964		ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
965		if (ifa != NULL) {
966			ip->ip_src.s_addr =
967			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
968			ifa_free(ifa);
969		} else
970			ip->ip_src.s_addr = 0;
971		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
972
973		ch_ptr = (struct carp_header *)(&ip[1]);
974		bcopy(&ch, ch_ptr, sizeof(ch));
975		if (carp_prepare_ad(m, sc, ch_ptr))
976			goto resched;
977
978		m->m_data += sizeof(*ip);
979		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
980		m->m_data -= sizeof(*ip);
981
982		CARPSTATS_INC(carps_opackets);
983
984		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
985		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
986	}
987#endif /* INET */
988#ifdef INET6
989	if (sc->sc_naddrs6) {
990		struct ip6_hdr *ip6;
991
992		m = m_gethdr(M_NOWAIT, MT_DATA);
993		if (m == NULL) {
994			CARPSTATS_INC(carps_onomem);
995			goto resched;
996		}
997		len = sizeof(*ip6) + sizeof(ch);
998		m->m_pkthdr.len = len;
999		m->m_pkthdr.rcvif = NULL;
1000		m->m_len = len;
1001		M_ALIGN(m, m->m_len);
1002		m->m_flags |= M_MCAST;
1003		ip6 = mtod(m, struct ip6_hdr *);
1004		bzero(ip6, sizeof(*ip6));
1005		ip6->ip6_vfc |= IPV6_VERSION;
1006		/* Traffic class isn't defined in ip6 struct instead
1007		 * it gets offset into flowid field */
1008		ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
1009		    IPTOS_DSCP_OFFSET));
1010		ip6->ip6_hlim = CARP_DFLTTL;
1011		ip6->ip6_nxt = IPPROTO_CARP;
1012
1013		/* set the source address */
1014		ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1015		if (ifa != NULL) {
1016			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1017			    sizeof(struct in6_addr));
1018			ifa_free(ifa);
1019		} else
1020			/* This should never happen with IPv6. */
1021			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1022
1023		/* Set the multicast destination. */
1024		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1025		ip6->ip6_dst.s6_addr8[15] = 0x12;
1026		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1027			m_freem(m);
1028			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1029			goto resched;
1030		}
1031
1032		ch_ptr = (struct carp_header *)(&ip6[1]);
1033		bcopy(&ch, ch_ptr, sizeof(ch));
1034		if (carp_prepare_ad(m, sc, ch_ptr))
1035			goto resched;
1036
1037		m->m_data += sizeof(*ip6);
1038		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1039		m->m_data -= sizeof(*ip6);
1040
1041		CARPSTATS_INC(carps_opackets6);
1042
1043		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1044		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1045	}
1046#endif /* INET6 */
1047
1048resched:
1049	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1050}
1051
1052static void
1053carp_addroute(struct carp_softc *sc)
1054{
1055	struct ifaddr *ifa;
1056
1057	CARP_FOREACH_IFA(sc, ifa)
1058		carp_ifa_addroute(ifa);
1059}
1060
1061static void
1062carp_ifa_addroute(struct ifaddr *ifa)
1063{
1064
1065	switch (ifa->ifa_addr->sa_family) {
1066#ifdef INET
1067	case AF_INET:
1068		in_addprefix(ifatoia(ifa));
1069		ifa_add_loopback_route(ifa,
1070		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1071		break;
1072#endif
1073#ifdef INET6
1074	case AF_INET6:
1075		ifa_add_loopback_route(ifa,
1076		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1077		nd6_add_ifa_lle(ifatoia6(ifa));
1078		break;
1079#endif
1080	}
1081}
1082
1083static void
1084carp_delroute(struct carp_softc *sc)
1085{
1086	struct ifaddr *ifa;
1087
1088	CARP_FOREACH_IFA(sc, ifa)
1089		carp_ifa_delroute(ifa);
1090}
1091
1092static void
1093carp_ifa_delroute(struct ifaddr *ifa)
1094{
1095
1096	switch (ifa->ifa_addr->sa_family) {
1097#ifdef INET
1098	case AF_INET:
1099		ifa_del_loopback_route(ifa,
1100		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1101		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1102		break;
1103#endif
1104#ifdef INET6
1105	case AF_INET6:
1106		ifa_del_loopback_route(ifa,
1107		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1108		nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1109		break;
1110#endif
1111	}
1112}
1113
1114int
1115carp_master(struct ifaddr *ifa)
1116{
1117	struct carp_softc *sc = ifa->ifa_carp;
1118
1119	return (sc->sc_state == MASTER);
1120}
1121
1122#ifdef INET
1123/*
1124 * Broadcast a gratuitous ARP request containing
1125 * the virtual router MAC address for each IP address
1126 * associated with the virtual router.
1127 */
1128static void
1129carp_send_arp(struct carp_softc *sc)
1130{
1131	struct ifaddr *ifa;
1132	struct in_addr addr;
1133
1134	NET_EPOCH_ASSERT();
1135
1136	CARP_FOREACH_IFA(sc, ifa) {
1137		if (ifa->ifa_addr->sa_family != AF_INET)
1138			continue;
1139		addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1140		arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1141	}
1142}
1143
1144int
1145carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1146{
1147	struct carp_softc *sc = ifa->ifa_carp;
1148
1149	if (sc->sc_state == MASTER) {
1150		*enaddr = LLADDR(&sc->sc_addr);
1151		return (1);
1152	}
1153
1154	return (0);
1155}
1156#endif
1157
1158#ifdef INET6
1159static void
1160carp_send_na(struct carp_softc *sc)
1161{
1162	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1163	struct ifaddr *ifa;
1164	struct in6_addr *in6;
1165
1166	CARP_FOREACH_IFA(sc, ifa) {
1167		if (ifa->ifa_addr->sa_family != AF_INET6)
1168			continue;
1169
1170		in6 = IFA_IN6(ifa);
1171		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1172		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1173		DELAY(1000);	/* XXX */
1174	}
1175}
1176
1177/*
1178 * Returns ifa in case it's a carp address and it is MASTER, or if the address
1179 * matches and is not a carp address.  Returns NULL otherwise.
1180 */
1181struct ifaddr *
1182carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1183{
1184	struct ifaddr *ifa;
1185
1186	NET_EPOCH_ASSERT();
1187
1188	ifa = NULL;
1189	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1190		if (ifa->ifa_addr->sa_family != AF_INET6)
1191			continue;
1192		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1193			continue;
1194		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1195			ifa = NULL;
1196		else
1197			ifa_ref(ifa);
1198		break;
1199	}
1200
1201	return (ifa);
1202}
1203
1204char *
1205carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1206{
1207	struct ifaddr *ifa;
1208
1209	NET_EPOCH_ASSERT();
1210
1211	IFNET_FOREACH_IFA(ifp, ifa)
1212		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1213		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1214			struct carp_softc *sc = ifa->ifa_carp;
1215			struct m_tag *mtag;
1216
1217			mtag = m_tag_get(PACKET_TAG_CARP,
1218			    sizeof(struct carp_softc *), M_NOWAIT);
1219			if (mtag == NULL)
1220				/* Better a bit than nothing. */
1221				return (LLADDR(&sc->sc_addr));
1222
1223			bcopy(&sc, mtag + 1, sizeof(sc));
1224			m_tag_prepend(m, mtag);
1225
1226			return (LLADDR(&sc->sc_addr));
1227		}
1228
1229	return (NULL);
1230}
1231#endif /* INET6 */
1232
1233int
1234carp_forus(struct ifnet *ifp, u_char *dhost)
1235{
1236	struct carp_softc *sc;
1237	uint8_t *ena = dhost;
1238
1239	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1240		return (0);
1241
1242	CIF_LOCK(ifp->if_carp);
1243	IFNET_FOREACH_CARP(ifp, sc) {
1244		/*
1245		 * CARP_LOCK() is not here, since would protect nothing, but
1246		 * cause deadlock with if_bridge, calling this under its lock.
1247		 */
1248		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1249		    ETHER_ADDR_LEN)) {
1250			CIF_UNLOCK(ifp->if_carp);
1251			return (1);
1252		}
1253	}
1254	CIF_UNLOCK(ifp->if_carp);
1255
1256	return (0);
1257}
1258
1259/* Master down timeout event, executed in callout context. */
1260static void
1261carp_master_down(void *v)
1262{
1263	struct carp_softc *sc = v;
1264	struct epoch_tracker et;
1265
1266	NET_EPOCH_ENTER(et);
1267	CARP_LOCK_ASSERT(sc);
1268
1269	CURVNET_SET(sc->sc_carpdev->if_vnet);
1270	if (sc->sc_state == BACKUP) {
1271		carp_master_down_locked(sc, "master timed out");
1272	}
1273	CURVNET_RESTORE();
1274
1275	CARP_UNLOCK(sc);
1276	NET_EPOCH_EXIT(et);
1277}
1278
1279static void
1280carp_master_down_locked(struct carp_softc *sc, const char *reason)
1281{
1282
1283	NET_EPOCH_ASSERT();
1284	CARP_LOCK_ASSERT(sc);
1285
1286	switch (sc->sc_state) {
1287	case BACKUP:
1288		carp_set_state(sc, MASTER, reason);
1289		carp_send_ad_locked(sc);
1290#ifdef INET
1291		carp_send_arp(sc);
1292#endif
1293#ifdef INET6
1294		carp_send_na(sc);
1295#endif
1296		carp_setrun(sc, 0);
1297		carp_addroute(sc);
1298		break;
1299	case INIT:
1300	case MASTER:
1301#ifdef INVARIANTS
1302		panic("carp: VHID %u@%s: master_down event in %s state\n",
1303		    sc->sc_vhid,
1304		    sc->sc_carpdev->if_xname,
1305		    sc->sc_state ? "MASTER" : "INIT");
1306#endif
1307		break;
1308	}
1309}
1310
1311/*
1312 * When in backup state, af indicates whether to reset the master down timer
1313 * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1314 */
1315static void
1316carp_setrun(struct carp_softc *sc, sa_family_t af)
1317{
1318	struct timeval tv;
1319
1320	CARP_LOCK_ASSERT(sc);
1321
1322	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1323	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1324	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1325	    !V_carp_allow)
1326		return;
1327
1328	switch (sc->sc_state) {
1329	case INIT:
1330		carp_set_state(sc, BACKUP, "initialization complete");
1331		carp_setrun(sc, 0);
1332		break;
1333	case BACKUP:
1334		callout_stop(&sc->sc_ad_tmo);
1335		tv.tv_sec = 3 * sc->sc_advbase;
1336		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1337		switch (af) {
1338#ifdef INET
1339		case AF_INET:
1340			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1341			    carp_master_down, sc);
1342			break;
1343#endif
1344#ifdef INET6
1345		case AF_INET6:
1346			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1347			    carp_master_down, sc);
1348			break;
1349#endif
1350		default:
1351#ifdef INET
1352			if (sc->sc_naddrs)
1353				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1354				    carp_master_down, sc);
1355#endif
1356#ifdef INET6
1357			if (sc->sc_naddrs6)
1358				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1359				    carp_master_down, sc);
1360#endif
1361			break;
1362		}
1363		break;
1364	case MASTER:
1365		tv.tv_sec = sc->sc_advbase;
1366		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1367		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1368		    carp_send_ad, sc);
1369		break;
1370	}
1371}
1372
1373/*
1374 * Setup multicast structures.
1375 */
1376static int
1377carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1378{
1379	struct ifnet *ifp = cif->cif_ifp;
1380	int error = 0;
1381
1382	switch (sa) {
1383#ifdef INET
1384	case AF_INET:
1385	    {
1386		struct ip_moptions *imo = &cif->cif_imo;
1387		struct in_mfilter *imf;
1388		struct in_addr addr;
1389
1390		if (ip_mfilter_first(&imo->imo_head) != NULL)
1391			return (0);
1392
1393		imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1394		ip_mfilter_init(&imo->imo_head);
1395		imo->imo_multicast_vif = -1;
1396
1397		addr.s_addr = htonl(INADDR_CARP_GROUP);
1398		if ((error = in_joingroup(ifp, &addr, NULL,
1399		    &imf->imf_inm)) != 0) {
1400			ip_mfilter_free(imf);
1401			break;
1402		}
1403
1404		ip_mfilter_insert(&imo->imo_head, imf);
1405		imo->imo_multicast_ifp = ifp;
1406		imo->imo_multicast_ttl = CARP_DFLTTL;
1407		imo->imo_multicast_loop = 0;
1408		break;
1409	   }
1410#endif
1411#ifdef INET6
1412	case AF_INET6:
1413	    {
1414		struct ip6_moptions *im6o = &cif->cif_im6o;
1415		struct in6_mfilter *im6f[2];
1416		struct in6_addr in6;
1417
1418		if (ip6_mfilter_first(&im6o->im6o_head))
1419			return (0);
1420
1421		im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1422		im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1423
1424		ip6_mfilter_init(&im6o->im6o_head);
1425		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1426		im6o->im6o_multicast_ifp = ifp;
1427
1428		/* Join IPv6 CARP multicast group. */
1429		bzero(&in6, sizeof(in6));
1430		in6.s6_addr16[0] = htons(0xff02);
1431		in6.s6_addr8[15] = 0x12;
1432		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1433			ip6_mfilter_free(im6f[0]);
1434			ip6_mfilter_free(im6f[1]);
1435			break;
1436		}
1437		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1438			ip6_mfilter_free(im6f[0]);
1439			ip6_mfilter_free(im6f[1]);
1440			break;
1441		}
1442
1443		/* Join solicited multicast address. */
1444		bzero(&in6, sizeof(in6));
1445		in6.s6_addr16[0] = htons(0xff02);
1446		in6.s6_addr32[1] = 0;
1447		in6.s6_addr32[2] = htonl(1);
1448		in6.s6_addr32[3] = 0;
1449		in6.s6_addr8[12] = 0xff;
1450
1451		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1452			ip6_mfilter_free(im6f[0]);
1453			ip6_mfilter_free(im6f[1]);
1454			break;
1455		}
1456
1457		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1458			in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1459			ip6_mfilter_free(im6f[0]);
1460			ip6_mfilter_free(im6f[1]);
1461			break;
1462		}
1463		ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1464		ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1465		break;
1466	    }
1467#endif
1468	}
1469
1470	return (error);
1471}
1472
1473/*
1474 * Free multicast structures.
1475 */
1476static void
1477carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1478{
1479#ifdef INET
1480	struct ip_moptions *imo = &cif->cif_imo;
1481	struct in_mfilter *imf;
1482#endif
1483#ifdef INET6
1484	struct ip6_moptions *im6o = &cif->cif_im6o;
1485	struct in6_mfilter *im6f;
1486#endif
1487	sx_assert(&carp_sx, SA_XLOCKED);
1488
1489	switch (sa) {
1490#ifdef INET
1491	case AF_INET:
1492		if (cif->cif_naddrs != 0)
1493			break;
1494
1495		while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1496			ip_mfilter_remove(&imo->imo_head, imf);
1497			in_leavegroup(imf->imf_inm, NULL);
1498			ip_mfilter_free(imf);
1499		}
1500		break;
1501#endif
1502#ifdef INET6
1503	case AF_INET6:
1504		if (cif->cif_naddrs6 != 0)
1505			break;
1506
1507		while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1508			ip6_mfilter_remove(&im6o->im6o_head, im6f);
1509			in6_leavegroup(im6f->im6f_in6m, NULL);
1510			ip6_mfilter_free(im6f);
1511		}
1512		break;
1513#endif
1514	}
1515}
1516
1517int
1518carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1519{
1520	struct m_tag *mtag;
1521	struct carp_softc *sc;
1522
1523	if (!sa)
1524		return (0);
1525
1526	switch (sa->sa_family) {
1527#ifdef INET
1528	case AF_INET:
1529		break;
1530#endif
1531#ifdef INET6
1532	case AF_INET6:
1533		break;
1534#endif
1535	default:
1536		return (0);
1537	}
1538
1539	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1540	if (mtag == NULL)
1541		return (0);
1542
1543	bcopy(mtag + 1, &sc, sizeof(sc));
1544
1545	/* Set the source MAC address to the Virtual Router MAC Address. */
1546	switch (ifp->if_type) {
1547	case IFT_ETHER:
1548	case IFT_BRIDGE:
1549	case IFT_L2VLAN: {
1550			struct ether_header *eh;
1551
1552			eh = mtod(m, struct ether_header *);
1553			eh->ether_shost[0] = 0;
1554			eh->ether_shost[1] = 0;
1555			eh->ether_shost[2] = 0x5e;
1556			eh->ether_shost[3] = 0;
1557			eh->ether_shost[4] = 1;
1558			eh->ether_shost[5] = sc->sc_vhid;
1559		}
1560		break;
1561	default:
1562		printf("%s: carp is not supported for the %d interface type\n",
1563		    ifp->if_xname, ifp->if_type);
1564		return (EOPNOTSUPP);
1565	}
1566
1567	return (0);
1568}
1569
1570static struct carp_softc*
1571carp_alloc(struct ifnet *ifp)
1572{
1573	struct carp_softc *sc;
1574	struct carp_if *cif;
1575
1576	sx_assert(&carp_sx, SA_XLOCKED);
1577
1578	if ((cif = ifp->if_carp) == NULL)
1579		cif = carp_alloc_if(ifp);
1580
1581	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1582
1583	sc->sc_advbase = CARP_DFLTINTV;
1584	sc->sc_vhid = -1;	/* required setting */
1585	sc->sc_init_counter = 1;
1586	sc->sc_state = INIT;
1587
1588	sc->sc_ifasiz = sizeof(struct ifaddr *);
1589	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1590	sc->sc_carpdev = ifp;
1591
1592	CARP_LOCK_INIT(sc);
1593#ifdef INET
1594	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1595#endif
1596#ifdef INET6
1597	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1598#endif
1599	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1600
1601	CIF_LOCK(cif);
1602	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1603	CIF_UNLOCK(cif);
1604
1605	mtx_lock(&carp_mtx);
1606	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1607	mtx_unlock(&carp_mtx);
1608
1609	return (sc);
1610}
1611
1612static void
1613carp_grow_ifas(struct carp_softc *sc)
1614{
1615	struct ifaddr **new;
1616
1617	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1618	CARP_LOCK(sc);
1619	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1620	free(sc->sc_ifas, M_CARP);
1621	sc->sc_ifas = new;
1622	sc->sc_ifasiz *= 2;
1623	CARP_UNLOCK(sc);
1624}
1625
1626static void
1627carp_destroy(struct carp_softc *sc)
1628{
1629	struct ifnet *ifp = sc->sc_carpdev;
1630	struct carp_if *cif = ifp->if_carp;
1631
1632	sx_assert(&carp_sx, SA_XLOCKED);
1633
1634	if (sc->sc_suppress)
1635		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1636	CARP_UNLOCK(sc);
1637
1638	CIF_LOCK(cif);
1639	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1640	CIF_UNLOCK(cif);
1641
1642	mtx_lock(&carp_mtx);
1643	LIST_REMOVE(sc, sc_next);
1644	mtx_unlock(&carp_mtx);
1645
1646	callout_drain(&sc->sc_ad_tmo);
1647#ifdef INET
1648	callout_drain(&sc->sc_md_tmo);
1649#endif
1650#ifdef INET6
1651	callout_drain(&sc->sc_md6_tmo);
1652#endif
1653	CARP_LOCK_DESTROY(sc);
1654
1655	free(sc->sc_ifas, M_CARP);
1656	free(sc, M_CARP);
1657}
1658
1659static struct carp_if*
1660carp_alloc_if(struct ifnet *ifp)
1661{
1662	struct carp_if *cif;
1663	int error;
1664
1665	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1666
1667	if ((error = ifpromisc(ifp, 1)) != 0)
1668		printf("%s: ifpromisc(%s) failed: %d\n",
1669		    __func__, ifp->if_xname, error);
1670	else
1671		cif->cif_flags |= CIF_PROMISC;
1672
1673	CIF_LOCK_INIT(cif);
1674	cif->cif_ifp = ifp;
1675	TAILQ_INIT(&cif->cif_vrs);
1676
1677	IF_ADDR_WLOCK(ifp);
1678	ifp->if_carp = cif;
1679	if_ref(ifp);
1680	IF_ADDR_WUNLOCK(ifp);
1681
1682	return (cif);
1683}
1684
1685static void
1686carp_free_if(struct carp_if *cif)
1687{
1688	struct ifnet *ifp = cif->cif_ifp;
1689
1690	CIF_LOCK_ASSERT(cif);
1691	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1692	    __func__));
1693
1694	IF_ADDR_WLOCK(ifp);
1695	ifp->if_carp = NULL;
1696	IF_ADDR_WUNLOCK(ifp);
1697
1698	CIF_LOCK_DESTROY(cif);
1699
1700	if (cif->cif_flags & CIF_PROMISC)
1701		ifpromisc(ifp, 0);
1702	if_rele(ifp);
1703
1704	free(cif, M_CARP);
1705}
1706
1707static void
1708carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1709{
1710
1711	CARP_LOCK(sc);
1712	carpr->carpr_state = sc->sc_state;
1713	carpr->carpr_vhid = sc->sc_vhid;
1714	carpr->carpr_advbase = sc->sc_advbase;
1715	carpr->carpr_advskew = sc->sc_advskew;
1716	if (priv)
1717		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1718	else
1719		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1720	CARP_UNLOCK(sc);
1721}
1722
1723int
1724carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1725{
1726	struct carpreq carpr;
1727	struct ifnet *ifp;
1728	struct carp_softc *sc = NULL;
1729	int error = 0, locked = 0;
1730
1731	if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1732		return (error);
1733
1734	ifp = ifunit_ref(ifr->ifr_name);
1735	if (ifp == NULL)
1736		return (ENXIO);
1737
1738	switch (ifp->if_type) {
1739	case IFT_ETHER:
1740	case IFT_L2VLAN:
1741	case IFT_BRIDGE:
1742		break;
1743	default:
1744		error = EOPNOTSUPP;
1745		goto out;
1746	}
1747
1748	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1749		error = EADDRNOTAVAIL;
1750		goto out;
1751	}
1752
1753	sx_xlock(&carp_sx);
1754	switch (cmd) {
1755	case SIOCSVH:
1756		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1757			break;
1758		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1759		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1760			error = EINVAL;
1761			break;
1762		}
1763
1764		if (ifp->if_carp) {
1765			IFNET_FOREACH_CARP(ifp, sc)
1766				if (sc->sc_vhid == carpr.carpr_vhid)
1767					break;
1768		}
1769		if (sc == NULL) {
1770			sc = carp_alloc(ifp);
1771			CARP_LOCK(sc);
1772			sc->sc_vhid = carpr.carpr_vhid;
1773			LLADDR(&sc->sc_addr)[0] = 0;
1774			LLADDR(&sc->sc_addr)[1] = 0;
1775			LLADDR(&sc->sc_addr)[2] = 0x5e;
1776			LLADDR(&sc->sc_addr)[3] = 0;
1777			LLADDR(&sc->sc_addr)[4] = 1;
1778			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1779		} else
1780			CARP_LOCK(sc);
1781		locked = 1;
1782		if (carpr.carpr_advbase > 0) {
1783			if (carpr.carpr_advbase > 255 ||
1784			    carpr.carpr_advbase < CARP_DFLTINTV) {
1785				error = EINVAL;
1786				break;
1787			}
1788			sc->sc_advbase = carpr.carpr_advbase;
1789		}
1790		if (carpr.carpr_advskew >= 255) {
1791			error = EINVAL;
1792			break;
1793		}
1794		sc->sc_advskew = carpr.carpr_advskew;
1795		if (carpr.carpr_key[0] != '\0') {
1796			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1797			carp_hmac_prepare(sc);
1798		}
1799		if (sc->sc_state != INIT &&
1800		    carpr.carpr_state != sc->sc_state) {
1801			switch (carpr.carpr_state) {
1802			case BACKUP:
1803				callout_stop(&sc->sc_ad_tmo);
1804				carp_set_state(sc, BACKUP,
1805				    "user requested via ifconfig");
1806				carp_setrun(sc, 0);
1807				carp_delroute(sc);
1808				break;
1809			case MASTER:
1810				carp_master_down_locked(sc,
1811				    "user requested via ifconfig");
1812				break;
1813			default:
1814				break;
1815			}
1816		}
1817		break;
1818
1819	case SIOCGVH:
1820	    {
1821		int priveleged;
1822
1823		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1824			error = EINVAL;
1825			break;
1826		}
1827		if (carpr.carpr_count < 1) {
1828			error = EMSGSIZE;
1829			break;
1830		}
1831		if (ifp->if_carp == NULL) {
1832			error = ENOENT;
1833			break;
1834		}
1835
1836		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1837		if (carpr.carpr_vhid != 0) {
1838			IFNET_FOREACH_CARP(ifp, sc)
1839				if (sc->sc_vhid == carpr.carpr_vhid)
1840					break;
1841			if (sc == NULL) {
1842				error = ENOENT;
1843				break;
1844			}
1845			carp_carprcp(&carpr, sc, priveleged);
1846			error = copyout(&carpr, ifr_data_get_ptr(ifr),
1847			    sizeof(carpr));
1848		} else  {
1849			int i, count;
1850
1851			count = 0;
1852			IFNET_FOREACH_CARP(ifp, sc)
1853				count++;
1854
1855			if (count > carpr.carpr_count) {
1856				CIF_UNLOCK(ifp->if_carp);
1857				error = EMSGSIZE;
1858				break;
1859			}
1860
1861			i = 0;
1862			IFNET_FOREACH_CARP(ifp, sc) {
1863				carp_carprcp(&carpr, sc, priveleged);
1864				carpr.carpr_count = count;
1865				error = copyout(&carpr,
1866				    (char *)ifr_data_get_ptr(ifr) +
1867				    (i * sizeof(carpr)), sizeof(carpr));
1868				if (error) {
1869					CIF_UNLOCK(ifp->if_carp);
1870					break;
1871				}
1872				i++;
1873			}
1874		}
1875		break;
1876	    }
1877	default:
1878		error = EINVAL;
1879	}
1880	sx_xunlock(&carp_sx);
1881
1882out:
1883	if (locked)
1884		CARP_UNLOCK(sc);
1885	if_rele(ifp);
1886
1887	return (error);
1888}
1889
1890static int
1891carp_get_vhid(struct ifaddr *ifa)
1892{
1893
1894	if (ifa == NULL || ifa->ifa_carp == NULL)
1895		return (0);
1896
1897	return (ifa->ifa_carp->sc_vhid);
1898}
1899
1900int
1901carp_attach(struct ifaddr *ifa, int vhid)
1902{
1903	struct ifnet *ifp = ifa->ifa_ifp;
1904	struct carp_if *cif = ifp->if_carp;
1905	struct carp_softc *sc;
1906	int index, error;
1907
1908	KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1909
1910	switch (ifa->ifa_addr->sa_family) {
1911#ifdef INET
1912	case AF_INET:
1913#endif
1914#ifdef INET6
1915	case AF_INET6:
1916#endif
1917		break;
1918	default:
1919		return (EPROTOTYPE);
1920	}
1921
1922	sx_xlock(&carp_sx);
1923	if (ifp->if_carp == NULL) {
1924		sx_xunlock(&carp_sx);
1925		return (ENOPROTOOPT);
1926	}
1927
1928	IFNET_FOREACH_CARP(ifp, sc)
1929		if (sc->sc_vhid == vhid)
1930			break;
1931	if (sc == NULL) {
1932		sx_xunlock(&carp_sx);
1933		return (ENOENT);
1934	}
1935
1936	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1937	if (error) {
1938		CIF_FREE(cif);
1939		sx_xunlock(&carp_sx);
1940		return (error);
1941	}
1942
1943	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1944	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1945		carp_grow_ifas(sc);
1946
1947	switch (ifa->ifa_addr->sa_family) {
1948#ifdef INET
1949	case AF_INET:
1950		cif->cif_naddrs++;
1951		sc->sc_naddrs++;
1952		break;
1953#endif
1954#ifdef INET6
1955	case AF_INET6:
1956		cif->cif_naddrs6++;
1957		sc->sc_naddrs6++;
1958		break;
1959#endif
1960	}
1961
1962	ifa_ref(ifa);
1963
1964	CARP_LOCK(sc);
1965	sc->sc_ifas[index - 1] = ifa;
1966	ifa->ifa_carp = sc;
1967	carp_hmac_prepare(sc);
1968	carp_sc_state(sc);
1969	CARP_UNLOCK(sc);
1970
1971	sx_xunlock(&carp_sx);
1972
1973	return (0);
1974}
1975
1976void
1977carp_detach(struct ifaddr *ifa, bool keep_cif)
1978{
1979	struct ifnet *ifp = ifa->ifa_ifp;
1980	struct carp_if *cif = ifp->if_carp;
1981	struct carp_softc *sc = ifa->ifa_carp;
1982	int i, index;
1983
1984	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1985
1986	sx_xlock(&carp_sx);
1987
1988	CARP_LOCK(sc);
1989	/* Shift array. */
1990	index = sc->sc_naddrs + sc->sc_naddrs6;
1991	for (i = 0; i < index; i++)
1992		if (sc->sc_ifas[i] == ifa)
1993			break;
1994	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1995	for (; i < index - 1; i++)
1996		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1997	sc->sc_ifas[index - 1] = NULL;
1998
1999	switch (ifa->ifa_addr->sa_family) {
2000#ifdef INET
2001	case AF_INET:
2002		cif->cif_naddrs--;
2003		sc->sc_naddrs--;
2004		break;
2005#endif
2006#ifdef INET6
2007	case AF_INET6:
2008		cif->cif_naddrs6--;
2009		sc->sc_naddrs6--;
2010		break;
2011#endif
2012	}
2013
2014	carp_ifa_delroute(ifa);
2015	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
2016
2017	ifa->ifa_carp = NULL;
2018	ifa_free(ifa);
2019
2020	carp_hmac_prepare(sc);
2021	carp_sc_state(sc);
2022
2023	if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2024		carp_destroy(sc);
2025	else
2026		CARP_UNLOCK(sc);
2027
2028	if (!keep_cif)
2029		CIF_FREE(cif);
2030
2031	sx_xunlock(&carp_sx);
2032}
2033
2034static void
2035carp_set_state(struct carp_softc *sc, int state, const char *reason)
2036{
2037
2038	CARP_LOCK_ASSERT(sc);
2039
2040	if (sc->sc_state != state) {
2041		const char *carp_states[] = { CARP_STATES };
2042		char subsys[IFNAMSIZ+5];
2043
2044		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2045		    sc->sc_carpdev->if_xname);
2046
2047		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2048		    carp_states[sc->sc_state], carp_states[state], reason);
2049
2050		sc->sc_state = state;
2051
2052		devctl_notify("CARP", subsys, carp_states[state], NULL);
2053	}
2054}
2055
2056static void
2057carp_linkstate(struct ifnet *ifp)
2058{
2059	struct carp_softc *sc;
2060
2061	CIF_LOCK(ifp->if_carp);
2062	IFNET_FOREACH_CARP(ifp, sc) {
2063		CARP_LOCK(sc);
2064		carp_sc_state(sc);
2065		CARP_UNLOCK(sc);
2066	}
2067	CIF_UNLOCK(ifp->if_carp);
2068}
2069
2070static void
2071carp_sc_state(struct carp_softc *sc)
2072{
2073
2074	CARP_LOCK_ASSERT(sc);
2075
2076	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2077	    !(sc->sc_carpdev->if_flags & IFF_UP) ||
2078	    !V_carp_allow) {
2079		callout_stop(&sc->sc_ad_tmo);
2080#ifdef INET
2081		callout_stop(&sc->sc_md_tmo);
2082#endif
2083#ifdef INET6
2084		callout_stop(&sc->sc_md6_tmo);
2085#endif
2086		carp_set_state(sc, INIT, "hardware interface down");
2087		carp_setrun(sc, 0);
2088		if (!sc->sc_suppress)
2089			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2090		sc->sc_suppress = 1;
2091	} else {
2092		carp_set_state(sc, INIT, "hardware interface up");
2093		carp_setrun(sc, 0);
2094		if (sc->sc_suppress)
2095			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2096		sc->sc_suppress = 0;
2097	}
2098}
2099
2100static void
2101carp_demote_adj(int adj, char *reason)
2102{
2103	atomic_add_int(&V_carp_demotion, adj);
2104	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2105	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2106}
2107
2108static int
2109carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2110{
2111	int new, error;
2112	struct carp_softc *sc;
2113
2114	new = V_carp_allow;
2115	error = sysctl_handle_int(oidp, &new, 0, req);
2116	if (error || !req->newptr)
2117		return (error);
2118
2119	if (V_carp_allow != new) {
2120		V_carp_allow = new;
2121
2122		mtx_lock(&carp_mtx);
2123		LIST_FOREACH(sc, &carp_list, sc_next) {
2124			CARP_LOCK(sc);
2125			if (curvnet == sc->sc_carpdev->if_vnet)
2126				carp_sc_state(sc);
2127			CARP_UNLOCK(sc);
2128		}
2129		mtx_unlock(&carp_mtx);
2130	}
2131
2132	return (0);
2133}
2134
2135static int
2136carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2137{
2138	int new, error;
2139
2140	new = V_carp_dscp;
2141	error = sysctl_handle_int(oidp, &new, 0, req);
2142	if (error || !req->newptr)
2143		return (error);
2144
2145	if (new < 0 || new > 63)
2146		return (EINVAL);
2147
2148	V_carp_dscp = new;
2149
2150	return (0);
2151}
2152
2153static int
2154carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2155{
2156	int new, error;
2157
2158	new = V_carp_demotion;
2159	error = sysctl_handle_int(oidp, &new, 0, req);
2160	if (error || !req->newptr)
2161		return (error);
2162
2163	carp_demote_adj(new, "sysctl");
2164
2165	return (0);
2166}
2167
2168#ifdef INET
2169extern  struct domain inetdomain;
2170static struct protosw in_carp_protosw = {
2171	.pr_type =		SOCK_RAW,
2172	.pr_domain =		&inetdomain,
2173	.pr_protocol =		IPPROTO_CARP,
2174	.pr_flags =		PR_ATOMIC|PR_ADDR,
2175	.pr_input =		carp_input,
2176	.pr_output =		rip_output,
2177	.pr_ctloutput =		rip_ctloutput,
2178	.pr_usrreqs =		&rip_usrreqs
2179};
2180#endif
2181
2182#ifdef INET6
2183extern	struct domain inet6domain;
2184static struct protosw in6_carp_protosw = {
2185	.pr_type =		SOCK_RAW,
2186	.pr_domain =		&inet6domain,
2187	.pr_protocol =		IPPROTO_CARP,
2188	.pr_flags =		PR_ATOMIC|PR_ADDR,
2189	.pr_input =		carp6_input,
2190	.pr_output =		rip6_output,
2191	.pr_ctloutput =		rip6_ctloutput,
2192	.pr_usrreqs =		&rip6_usrreqs
2193};
2194#endif
2195
2196static void
2197carp_mod_cleanup(void)
2198{
2199
2200#ifdef INET
2201	if (proto_reg[CARP_INET] == 0) {
2202		(void)ipproto_unregister(IPPROTO_CARP);
2203		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2204		proto_reg[CARP_INET] = -1;
2205	}
2206	carp_iamatch_p = NULL;
2207#endif
2208#ifdef INET6
2209	if (proto_reg[CARP_INET6] == 0) {
2210		(void)ip6proto_unregister(IPPROTO_CARP);
2211		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2212		proto_reg[CARP_INET6] = -1;
2213	}
2214	carp_iamatch6_p = NULL;
2215	carp_macmatch6_p = NULL;
2216#endif
2217	carp_ioctl_p = NULL;
2218	carp_attach_p = NULL;
2219	carp_detach_p = NULL;
2220	carp_get_vhid_p = NULL;
2221	carp_linkstate_p = NULL;
2222	carp_forus_p = NULL;
2223	carp_output_p = NULL;
2224	carp_demote_adj_p = NULL;
2225	carp_master_p = NULL;
2226	mtx_unlock(&carp_mtx);
2227	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2228	mtx_destroy(&carp_mtx);
2229	sx_destroy(&carp_sx);
2230}
2231
2232static int
2233carp_mod_load(void)
2234{
2235	int err;
2236
2237	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2238	sx_init(&carp_sx, "carp_sx");
2239	LIST_INIT(&carp_list);
2240	carp_get_vhid_p = carp_get_vhid;
2241	carp_forus_p = carp_forus;
2242	carp_output_p = carp_output;
2243	carp_linkstate_p = carp_linkstate;
2244	carp_ioctl_p = carp_ioctl;
2245	carp_attach_p = carp_attach;
2246	carp_detach_p = carp_detach;
2247	carp_demote_adj_p = carp_demote_adj;
2248	carp_master_p = carp_master;
2249#ifdef INET6
2250	carp_iamatch6_p = carp_iamatch6;
2251	carp_macmatch6_p = carp_macmatch6;
2252	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2253	    (struct protosw *)&in6_carp_protosw);
2254	if (proto_reg[CARP_INET6]) {
2255		printf("carp: error %d attaching to PF_INET6\n",
2256		    proto_reg[CARP_INET6]);
2257		carp_mod_cleanup();
2258		return (proto_reg[CARP_INET6]);
2259	}
2260	err = ip6proto_register(IPPROTO_CARP);
2261	if (err) {
2262		printf("carp: error %d registering with INET6\n", err);
2263		carp_mod_cleanup();
2264		return (err);
2265	}
2266#endif
2267#ifdef INET
2268	carp_iamatch_p = carp_iamatch;
2269	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2270	if (proto_reg[CARP_INET]) {
2271		printf("carp: error %d attaching to PF_INET\n",
2272		    proto_reg[CARP_INET]);
2273		carp_mod_cleanup();
2274		return (proto_reg[CARP_INET]);
2275	}
2276	err = ipproto_register(IPPROTO_CARP);
2277	if (err) {
2278		printf("carp: error %d registering with INET\n", err);
2279		carp_mod_cleanup();
2280		return (err);
2281	}
2282#endif
2283	return (0);
2284}
2285
2286static int
2287carp_modevent(module_t mod, int type, void *data)
2288{
2289	switch (type) {
2290	case MOD_LOAD:
2291		return carp_mod_load();
2292		/* NOTREACHED */
2293	case MOD_UNLOAD:
2294		mtx_lock(&carp_mtx);
2295		if (LIST_EMPTY(&carp_list))
2296			carp_mod_cleanup();
2297		else {
2298			mtx_unlock(&carp_mtx);
2299			return (EBUSY);
2300		}
2301		break;
2302
2303	default:
2304		return (EINVAL);
2305	}
2306
2307	return (0);
2308}
2309
2310static moduledata_t carp_mod = {
2311	"carp",
2312	carp_modevent,
2313	0
2314};
2315
2316DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2317