xref: /freebsd/sys/netinet/ip_carp.c (revision f18976136625a7d016e97bfd9eabddf640b3e06d)
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/bus.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 
89 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
90 
91 struct carp_softc {
92 	struct ifnet		*sc_carpdev;	/* Pointer to parent ifnet. */
93 	struct ifaddr		**sc_ifas;	/* Our ifaddrs. */
94 	struct sockaddr_dl	sc_addr;	/* Our link level address. */
95 	struct callout		sc_ad_tmo;	/* Advertising timeout. */
96 #ifdef INET
97 	struct callout		sc_md_tmo;	/* Master down timeout. */
98 #endif
99 #ifdef INET6
100 	struct callout 		sc_md6_tmo;	/* XXX: Master down timeout. */
101 #endif
102 	struct mtx		sc_mtx;
103 
104 	int			sc_vhid;
105 	int			sc_advskew;
106 	int			sc_advbase;
107 
108 	int			sc_naddrs;
109 	int			sc_naddrs6;
110 	int			sc_ifasiz;
111 	enum { INIT = 0, BACKUP, MASTER }	sc_state;
112 	int			sc_suppress;
113 	int			sc_sendad_errors;
114 #define	CARP_SENDAD_MAX_ERRORS	3
115 	int			sc_sendad_success;
116 #define	CARP_SENDAD_MIN_SUCCESS 3
117 
118 	int			sc_init_counter;
119 	uint64_t		sc_counter;
120 
121 	/* authentication */
122 #define	CARP_HMAC_PAD	64
123 	unsigned char sc_key[CARP_KEY_LEN];
124 	unsigned char sc_pad[CARP_HMAC_PAD];
125 	SHA1_CTX sc_sha1;
126 
127 	TAILQ_ENTRY(carp_softc)	sc_list;	/* On the carp_if list. */
128 	LIST_ENTRY(carp_softc)	sc_next;	/* On the global list. */
129 };
130 
131 struct carp_if {
132 #ifdef INET
133 	int	cif_naddrs;
134 #endif
135 #ifdef INET6
136 	int	cif_naddrs6;
137 #endif
138 	TAILQ_HEAD(, carp_softc) cif_vrs;
139 #ifdef INET
140 	struct ip_moptions 	 cif_imo;
141 #endif
142 #ifdef INET6
143 	struct ip6_moptions 	 cif_im6o;
144 #endif
145 	struct ifnet	*cif_ifp;
146 	struct mtx	cif_mtx;
147 	uint32_t	cif_flags;
148 #define	CIF_PROMISC	0x00000001
149 };
150 
151 #define	CARP_INET	0
152 #define	CARP_INET6	1
153 static int proto_reg[] = {-1, -1};
154 
155 /*
156  * Brief design of carp(4).
157  *
158  * Any carp-capable ifnet may have a list of carp softcs hanging off
159  * its ifp->if_carp pointer. Each softc represents one unique virtual
160  * host id, or vhid. The softc has a back pointer to the ifnet. All
161  * softcs are joined in a global list, which has quite limited use.
162  *
163  * Any interface address that takes part in CARP negotiation has a
164  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
165  * AF_INET or AF_INET6 address.
166  *
167  * Although, one can get the softc's backpointer to ifnet and traverse
168  * through its ifp->if_addrhead queue to find all interface addresses
169  * involved in CARP, we keep a growable array of ifaddr pointers. This
170  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
171  * do calls into the network stack, thus avoiding LORs.
172  *
173  * Locking:
174  *
175  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
176  * callout-driven events and ioctl()s.
177  *
178  * To traverse the list of softcs on an ifnet we use CIF_LOCK() 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. */
190 VNET_DEFINE_STATIC(int, carp_allow) = 1;
191 #define	V_carp_allow	VNET(carp_allow)
192 
193 /* Set DSCP in outgoing CARP packets. */
194 VNET_DEFINE_STATIC(int, carp_dscp) = 56;
195 #define	V_carp_dscp	VNET(carp_dscp)
196 
197 /* Preempt slower nodes. */
198 VNET_DEFINE_STATIC(int, carp_preempt) = 0;
199 #define	V_carp_preempt	VNET(carp_preempt)
200 
201 /* Log level. */
202 VNET_DEFINE_STATIC(int, carp_log) = 1;
203 #define	V_carp_log	VNET(carp_log)
204 
205 /* Global advskew demotion. */
206 VNET_DEFINE_STATIC(int, carp_demotion) = 0;
207 #define	V_carp_demotion	VNET(carp_demotion)
208 
209 /* Send error demotion factor. */
210 VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
211 #define	V_carp_senderr_adj	VNET(carp_senderr_adj)
212 
213 /* Iface down demotion factor. */
214 VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
215 #define	V_carp_ifdown_adj	VNET(carp_ifdown_adj)
216 
217 static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
218 static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
219 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
220 
221 SYSCTL_NODE(_net_inet, IPPROTO_CARP,	carp,	CTLFLAG_RW, 0,	"CARP");
222 SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
223     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, 0, 0, carp_allow_sysctl, "I",
224     "Accept incoming CARP packets");
225 SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
226     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW, 0, 0, carp_dscp_sysctl, "I",
227     "DSCP value for carp packets");
228 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
229     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
230 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
231     &VNET_NAME(carp_log), 0, "CARP log level");
232 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
233     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW,
234     0, 0, carp_demote_adj_sysctl, "I",
235     "Adjust demotion factor (skew of advskew)");
236 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
237     CTLFLAG_VNET | CTLFLAG_RW,
238     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
239 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
240     CTLFLAG_VNET | CTLFLAG_RW,
241     &VNET_NAME(carp_ifdown_adj), 0,
242     "Interface down demotion factor adjustment");
243 
244 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
245 VNET_PCPUSTAT_SYSINIT(carpstats);
246 VNET_PCPUSTAT_SYSUNINIT(carpstats);
247 
248 #define	CARPSTATS_ADD(name, val)	\
249     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
250 	sizeof(uint64_t)], (val))
251 #define	CARPSTATS_INC(name)		CARPSTATS_ADD(name, 1)
252 
253 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
254     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
255 
256 #define	CARP_LOCK_INIT(sc)	mtx_init(&(sc)->sc_mtx, "carp_softc",   \
257 	NULL, MTX_DEF)
258 #define	CARP_LOCK_DESTROY(sc)	mtx_destroy(&(sc)->sc_mtx)
259 #define	CARP_LOCK_ASSERT(sc)	mtx_assert(&(sc)->sc_mtx, MA_OWNED)
260 #define	CARP_LOCK(sc)		mtx_lock(&(sc)->sc_mtx)
261 #define	CARP_UNLOCK(sc)		mtx_unlock(&(sc)->sc_mtx)
262 #define	CIF_LOCK_INIT(cif)	mtx_init(&(cif)->cif_mtx, "carp_if",   \
263 	NULL, MTX_DEF)
264 #define	CIF_LOCK_DESTROY(cif)	mtx_destroy(&(cif)->cif_mtx)
265 #define	CIF_LOCK_ASSERT(cif)	mtx_assert(&(cif)->cif_mtx, MA_OWNED)
266 #define	CIF_LOCK(cif)		mtx_lock(&(cif)->cif_mtx)
267 #define	CIF_UNLOCK(cif)		mtx_unlock(&(cif)->cif_mtx)
268 #define	CIF_FREE(cif)	do {				\
269 		CIF_LOCK(cif);				\
270 		if (TAILQ_EMPTY(&(cif)->cif_vrs))	\
271 			carp_free_if(cif);		\
272 		else					\
273 			CIF_UNLOCK(cif);		\
274 } while (0)
275 
276 #define	CARP_LOG(...)	do {				\
277 	if (V_carp_log > 0)				\
278 		log(LOG_INFO, "carp: " __VA_ARGS__);	\
279 } while (0)
280 
281 #define	CARP_DEBUG(...)	do {				\
282 	if (V_carp_log > 1)				\
283 		log(LOG_DEBUG, __VA_ARGS__);		\
284 } while (0)
285 
286 #define	IFNET_FOREACH_IFA(ifp, ifa)					\
287 	CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link)	\
288 		if ((ifa)->ifa_carp != NULL)
289 
290 #define	CARP_FOREACH_IFA(sc, ifa)					\
291 	CARP_LOCK_ASSERT(sc);						\
292 	for (int _i = 0;						\
293 		_i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&		\
294 		((ifa) = sc->sc_ifas[_i]) != NULL;			\
295 		++_i)
296 
297 #define	IFNET_FOREACH_CARP(ifp, sc)					\
298 	KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) ||			\
299 	    sx_xlocked(&carp_sx), ("cif_vrs not locked"));		\
300 	TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
301 
302 #define	DEMOTE_ADVSKEW(sc)					\
303     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?	\
304     CARP_MAXSKEW : ((sc)->sc_advskew + V_carp_demotion))
305 
306 static void	carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
307 static struct carp_softc
308 		*carp_alloc(struct ifnet *);
309 static void	carp_destroy(struct carp_softc *);
310 static struct carp_if
311 		*carp_alloc_if(struct ifnet *);
312 static void	carp_free_if(struct carp_if *);
313 static void	carp_set_state(struct carp_softc *, int, const char* reason);
314 static void	carp_sc_state(struct carp_softc *);
315 static void	carp_setrun(struct carp_softc *, sa_family_t);
316 static void	carp_master_down(void *);
317 static void	carp_master_down_locked(struct carp_softc *,
318     		    const char* reason);
319 static void	carp_send_ad(void *);
320 static void	carp_send_ad_locked(struct carp_softc *);
321 static void	carp_addroute(struct carp_softc *);
322 static void	carp_ifa_addroute(struct ifaddr *);
323 static void	carp_delroute(struct carp_softc *);
324 static void	carp_ifa_delroute(struct ifaddr *);
325 static void	carp_send_ad_all(void *, int);
326 static void	carp_demote_adj(int, char *);
327 
328 static LIST_HEAD(, carp_softc) carp_list;
329 static struct mtx carp_mtx;
330 static struct sx carp_sx;
331 static struct task carp_sendall_task =
332     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
333 
334 static void
335 carp_hmac_prepare(struct carp_softc *sc)
336 {
337 	uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
338 	uint8_t vhid = sc->sc_vhid & 0xff;
339 	struct ifaddr *ifa;
340 	int i, found;
341 #ifdef INET
342 	struct in_addr last, cur, in;
343 #endif
344 #ifdef INET6
345 	struct in6_addr last6, cur6, in6;
346 #endif
347 
348 	CARP_LOCK_ASSERT(sc);
349 
350 	/* Compute ipad from key. */
351 	bzero(sc->sc_pad, sizeof(sc->sc_pad));
352 	bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
353 	for (i = 0; i < sizeof(sc->sc_pad); i++)
354 		sc->sc_pad[i] ^= 0x36;
355 
356 	/* Precompute first part of inner hash. */
357 	SHA1Init(&sc->sc_sha1);
358 	SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
359 	SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
360 	SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
361 	SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
362 #ifdef INET
363 	cur.s_addr = 0;
364 	do {
365 		found = 0;
366 		last = cur;
367 		cur.s_addr = 0xffffffff;
368 		CARP_FOREACH_IFA(sc, ifa) {
369 			in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
370 			if (ifa->ifa_addr->sa_family == AF_INET &&
371 			    ntohl(in.s_addr) > ntohl(last.s_addr) &&
372 			    ntohl(in.s_addr) < ntohl(cur.s_addr)) {
373 				cur.s_addr = in.s_addr;
374 				found++;
375 			}
376 		}
377 		if (found)
378 			SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
379 	} while (found);
380 #endif /* INET */
381 #ifdef INET6
382 	memset(&cur6, 0, sizeof(cur6));
383 	do {
384 		found = 0;
385 		last6 = cur6;
386 		memset(&cur6, 0xff, sizeof(cur6));
387 		CARP_FOREACH_IFA(sc, ifa) {
388 			in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
389 			if (IN6_IS_SCOPE_EMBED(&in6))
390 				in6.s6_addr16[1] = 0;
391 			if (ifa->ifa_addr->sa_family == AF_INET6 &&
392 			    memcmp(&in6, &last6, sizeof(in6)) > 0 &&
393 			    memcmp(&in6, &cur6, sizeof(in6)) < 0) {
394 				cur6 = in6;
395 				found++;
396 			}
397 		}
398 		if (found)
399 			SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
400 	} while (found);
401 #endif /* INET6 */
402 
403 	/* convert ipad to opad */
404 	for (i = 0; i < sizeof(sc->sc_pad); i++)
405 		sc->sc_pad[i] ^= 0x36 ^ 0x5c;
406 }
407 
408 static void
409 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
410     unsigned char md[20])
411 {
412 	SHA1_CTX sha1ctx;
413 
414 	CARP_LOCK_ASSERT(sc);
415 
416 	/* fetch first half of inner hash */
417 	bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
418 
419 	SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
420 	SHA1Final(md, &sha1ctx);
421 
422 	/* outer hash */
423 	SHA1Init(&sha1ctx);
424 	SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
425 	SHA1Update(&sha1ctx, md, 20);
426 	SHA1Final(md, &sha1ctx);
427 }
428 
429 static int
430 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
431     unsigned char md[20])
432 {
433 	unsigned char md2[20];
434 
435 	CARP_LOCK_ASSERT(sc);
436 
437 	carp_hmac_generate(sc, counter, md2);
438 
439 	return (bcmp(md, md2, sizeof(md2)));
440 }
441 
442 /*
443  * process input packet.
444  * we have rearranged checks order compared to the rfc,
445  * but it seems more efficient this way or not possible otherwise.
446  */
447 #ifdef INET
448 int
449 carp_input(struct mbuf **mp, int *offp, int proto)
450 {
451 	struct mbuf *m = *mp;
452 	struct ip *ip = mtod(m, struct ip *);
453 	struct carp_header *ch;
454 	int iplen, len;
455 
456 	iplen = *offp;
457 	*mp = NULL;
458 
459 	CARPSTATS_INC(carps_ipackets);
460 
461 	if (!V_carp_allow) {
462 		m_freem(m);
463 		return (IPPROTO_DONE);
464 	}
465 
466 	/* verify that the IP TTL is 255.  */
467 	if (ip->ip_ttl != CARP_DFLTTL) {
468 		CARPSTATS_INC(carps_badttl);
469 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
470 		    ip->ip_ttl,
471 		    m->m_pkthdr.rcvif->if_xname);
472 		m_freem(m);
473 		return (IPPROTO_DONE);
474 	}
475 
476 	iplen = ip->ip_hl << 2;
477 
478 	if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
479 		CARPSTATS_INC(carps_badlen);
480 		CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
481 		    "on %s\n", __func__, m->m_len - sizeof(struct ip),
482 		    m->m_pkthdr.rcvif->if_xname);
483 		m_freem(m);
484 		return (IPPROTO_DONE);
485 	}
486 
487 	if (iplen + sizeof(*ch) < m->m_len) {
488 		if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
489 			CARPSTATS_INC(carps_hdrops);
490 			CARP_DEBUG("%s: pullup failed\n", __func__);
491 			return (IPPROTO_DONE);
492 		}
493 		ip = mtod(m, struct ip *);
494 	}
495 	ch = (struct carp_header *)((char *)ip + iplen);
496 
497 	/*
498 	 * verify that the received packet length is
499 	 * equal to the CARP header
500 	 */
501 	len = iplen + sizeof(*ch);
502 	if (len > m->m_pkthdr.len) {
503 		CARPSTATS_INC(carps_badlen);
504 		CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
505 		    m->m_pkthdr.len,
506 		    m->m_pkthdr.rcvif->if_xname);
507 		m_freem(m);
508 		return (IPPROTO_DONE);
509 	}
510 
511 	if ((m = m_pullup(m, len)) == NULL) {
512 		CARPSTATS_INC(carps_hdrops);
513 		return (IPPROTO_DONE);
514 	}
515 	ip = mtod(m, struct ip *);
516 	ch = (struct carp_header *)((char *)ip + iplen);
517 
518 	/* verify the CARP checksum */
519 	m->m_data += iplen;
520 	if (in_cksum(m, len - iplen)) {
521 		CARPSTATS_INC(carps_badsum);
522 		CARP_DEBUG("%s: checksum failed on %s\n", __func__,
523 		    m->m_pkthdr.rcvif->if_xname);
524 		m_freem(m);
525 		return (IPPROTO_DONE);
526 	}
527 	m->m_data -= iplen;
528 
529 	carp_input_c(m, ch, AF_INET);
530 	return (IPPROTO_DONE);
531 }
532 #endif
533 
534 #ifdef INET6
535 int
536 carp6_input(struct mbuf **mp, int *offp, int proto)
537 {
538 	struct mbuf *m = *mp;
539 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
540 	struct carp_header *ch;
541 	u_int len;
542 
543 	CARPSTATS_INC(carps_ipackets6);
544 
545 	if (!V_carp_allow) {
546 		m_freem(m);
547 		return (IPPROTO_DONE);
548 	}
549 
550 	/* check if received on a valid carp interface */
551 	if (m->m_pkthdr.rcvif->if_carp == NULL) {
552 		CARPSTATS_INC(carps_badif);
553 		CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
554 		    __func__, m->m_pkthdr.rcvif->if_xname);
555 		m_freem(m);
556 		return (IPPROTO_DONE);
557 	}
558 
559 	/* verify that the IP TTL is 255 */
560 	if (ip6->ip6_hlim != CARP_DFLTTL) {
561 		CARPSTATS_INC(carps_badttl);
562 		CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
563 		    ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
564 		m_freem(m);
565 		return (IPPROTO_DONE);
566 	}
567 
568 	/* verify that we have a complete carp packet */
569 	len = m->m_len;
570 	IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
571 	if (ch == NULL) {
572 		CARPSTATS_INC(carps_badlen);
573 		CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
574 		return (IPPROTO_DONE);
575 	}
576 
577 
578 	/* verify the CARP checksum */
579 	m->m_data += *offp;
580 	if (in_cksum(m, sizeof(*ch))) {
581 		CARPSTATS_INC(carps_badsum);
582 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
583 		    m->m_pkthdr.rcvif->if_xname);
584 		m_freem(m);
585 		return (IPPROTO_DONE);
586 	}
587 	m->m_data -= *offp;
588 
589 	carp_input_c(m, ch, AF_INET6);
590 	return (IPPROTO_DONE);
591 }
592 #endif /* INET6 */
593 
594 /*
595  * This routine should not be necessary at all, but some switches
596  * (VMWare ESX vswitches) can echo our own packets back at us,
597  * and we must ignore them or they will cause us to drop out of
598  * MASTER mode.
599  *
600  * We cannot catch all cases of network loops.  Instead, what we
601  * do here is catch any packet that arrives with a carp header
602  * with a VHID of 0, that comes from an address that is our own.
603  * These packets are by definition "from us" (even if they are from
604  * a misconfigured host that is pretending to be us).
605  *
606  * The VHID test is outside this mini-function.
607  */
608 static int
609 carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
610 {
611 #ifdef INET
612 	struct ip *ip4;
613 	struct in_addr in4;
614 #endif
615 #ifdef INET6
616 	struct ip6_hdr *ip6;
617 	struct in6_addr in6;
618 #endif
619 
620 	switch (af) {
621 #ifdef INET
622 	case AF_INET:
623 		ip4 = mtod(m, struct ip *);
624 		in4 = ifatoia(ifa)->ia_addr.sin_addr;
625 		return (in4.s_addr == ip4->ip_src.s_addr);
626 #endif
627 #ifdef INET6
628 	case AF_INET6:
629 		ip6 = mtod(m, struct ip6_hdr *);
630 		in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
631 		return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
632 #endif
633 	default:
634 		break;
635 	}
636 	return (0);
637 }
638 
639 static void
640 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
641 {
642 	struct ifnet *ifp = m->m_pkthdr.rcvif;
643 	struct ifaddr *ifa, *match;
644 	struct carp_softc *sc;
645 	uint64_t tmp_counter;
646 	struct timeval sc_tv, ch_tv;
647 	int error;
648 
649 	NET_EPOCH_ASSERT();
650 
651 	/*
652 	 * Verify that the VHID is valid on the receiving interface.
653 	 *
654 	 * There should be just one match.  If there are none
655 	 * the VHID is not valid and we drop the packet.  If
656 	 * there are multiple VHID matches, take just the first
657 	 * one, for compatibility with previous code.  While we're
658 	 * scanning, check for obvious loops in the network topology
659 	 * (these should never happen, and as noted above, we may
660 	 * miss real loops; this is just a double-check).
661 	 */
662 	error = 0;
663 	match = NULL;
664 	IFNET_FOREACH_IFA(ifp, ifa) {
665 		if (match == NULL && ifa->ifa_carp != NULL &&
666 		    ifa->ifa_addr->sa_family == af &&
667 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid)
668 			match = ifa;
669 		if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
670 			error = ELOOP;
671 	}
672 	ifa = error ? NULL : match;
673 	if (ifa != NULL)
674 		ifa_ref(ifa);
675 
676 	if (ifa == NULL) {
677 		if (error == ELOOP) {
678 			CARP_DEBUG("dropping looped packet on interface %s\n",
679 			    ifp->if_xname);
680 			CARPSTATS_INC(carps_badif);	/* ??? */
681 		} else {
682 			CARPSTATS_INC(carps_badvhid);
683 		}
684 		m_freem(m);
685 		return;
686 	}
687 
688 	/* verify the CARP version. */
689 	if (ch->carp_version != CARP_VERSION) {
690 		CARPSTATS_INC(carps_badver);
691 		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
692 		    ch->carp_version);
693 		ifa_free(ifa);
694 		m_freem(m);
695 		return;
696 	}
697 
698 	sc = ifa->ifa_carp;
699 	CARP_LOCK(sc);
700 	ifa_free(ifa);
701 
702 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
703 		CARPSTATS_INC(carps_badauth);
704 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
705 		    sc->sc_vhid, ifp->if_xname);
706 		goto out;
707 	}
708 
709 	tmp_counter = ntohl(ch->carp_counter[0]);
710 	tmp_counter = tmp_counter<<32;
711 	tmp_counter += ntohl(ch->carp_counter[1]);
712 
713 	/* XXX Replay protection goes here */
714 
715 	sc->sc_init_counter = 0;
716 	sc->sc_counter = tmp_counter;
717 
718 	sc_tv.tv_sec = sc->sc_advbase;
719 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
720 	ch_tv.tv_sec = ch->carp_advbase;
721 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
722 
723 	switch (sc->sc_state) {
724 	case INIT:
725 		break;
726 	case MASTER:
727 		/*
728 		 * If we receive an advertisement from a master who's going to
729 		 * be more frequent than us, go into BACKUP state.
730 		 */
731 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
732 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
733 			callout_stop(&sc->sc_ad_tmo);
734 			carp_set_state(sc, BACKUP,
735 			    "more frequent advertisement received");
736 			carp_setrun(sc, 0);
737 			carp_delroute(sc);
738 		}
739 		break;
740 	case BACKUP:
741 		/*
742 		 * If we're pre-empting masters who advertise slower than us,
743 		 * and this one claims to be slower, treat him as down.
744 		 */
745 		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
746 			carp_master_down_locked(sc,
747 			    "preempting a slower master");
748 			break;
749 		}
750 
751 		/*
752 		 *  If the master is going to advertise at such a low frequency
753 		 *  that he's guaranteed to time out, we'd might as well just
754 		 *  treat him as timed out now.
755 		 */
756 		sc_tv.tv_sec = sc->sc_advbase * 3;
757 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
758 			carp_master_down_locked(sc, "master will time out");
759 			break;
760 		}
761 
762 		/*
763 		 * Otherwise, we reset the counter and wait for the next
764 		 * advertisement.
765 		 */
766 		carp_setrun(sc, af);
767 		break;
768 	}
769 
770 out:
771 	CARP_UNLOCK(sc);
772 	m_freem(m);
773 }
774 
775 static int
776 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
777 {
778 	struct m_tag *mtag;
779 
780 	if (sc->sc_init_counter) {
781 		/* this could also be seconds since unix epoch */
782 		sc->sc_counter = arc4random();
783 		sc->sc_counter = sc->sc_counter << 32;
784 		sc->sc_counter += arc4random();
785 	} else
786 		sc->sc_counter++;
787 
788 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
789 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
790 
791 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
792 
793 	/* Tag packet for carp_output */
794 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
795 	    M_NOWAIT)) == NULL) {
796 		m_freem(m);
797 		CARPSTATS_INC(carps_onomem);
798 		return (ENOMEM);
799 	}
800 	bcopy(&sc, mtag + 1, sizeof(sc));
801 	m_tag_prepend(m, mtag);
802 
803 	return (0);
804 }
805 
806 /*
807  * To avoid LORs and possible recursions this function shouldn't
808  * be called directly, but scheduled via taskqueue.
809  */
810 static void
811 carp_send_ad_all(void *ctx __unused, int pending __unused)
812 {
813 	struct carp_softc *sc;
814 
815 	mtx_lock(&carp_mtx);
816 	LIST_FOREACH(sc, &carp_list, sc_next)
817 		if (sc->sc_state == MASTER) {
818 			CARP_LOCK(sc);
819 			CURVNET_SET(sc->sc_carpdev->if_vnet);
820 			carp_send_ad_locked(sc);
821 			CURVNET_RESTORE();
822 			CARP_UNLOCK(sc);
823 		}
824 	mtx_unlock(&carp_mtx);
825 }
826 
827 /* Send a periodic advertisement, executed in callout context. */
828 static void
829 carp_send_ad(void *v)
830 {
831 	struct carp_softc *sc = v;
832 
833 	CARP_LOCK_ASSERT(sc);
834 	CURVNET_SET(sc->sc_carpdev->if_vnet);
835 	carp_send_ad_locked(sc);
836 	CURVNET_RESTORE();
837 	CARP_UNLOCK(sc);
838 }
839 
840 static void
841 carp_send_ad_error(struct carp_softc *sc, int error)
842 {
843 
844 	if (error) {
845 		if (sc->sc_sendad_errors < INT_MAX)
846 			sc->sc_sendad_errors++;
847 		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
848 			static const char fmt[] = "send error %d on %s";
849 			char msg[sizeof(fmt) + IFNAMSIZ];
850 
851 			sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
852 			carp_demote_adj(V_carp_senderr_adj, msg);
853 		}
854 		sc->sc_sendad_success = 0;
855 	} else {
856 		if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
857 		    ++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
858 			static const char fmt[] = "send ok on %s";
859 			char msg[sizeof(fmt) + IFNAMSIZ];
860 
861 			sprintf(msg, fmt, sc->sc_carpdev->if_xname);
862 			carp_demote_adj(-V_carp_senderr_adj, msg);
863 			sc->sc_sendad_errors = 0;
864 		} else
865 			sc->sc_sendad_errors = 0;
866 	}
867 }
868 
869 /*
870  * Pick the best ifaddr on the given ifp for sending CARP
871  * advertisements.
872  *
873  * "Best" here is defined by ifa_preferred().  This function is much
874  * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
875  *
876  * (This could be simplified to return the actual address, except that
877  * it has a different format in AF_INET and AF_INET6.)
878  */
879 static struct ifaddr *
880 carp_best_ifa(int af, struct ifnet *ifp)
881 {
882 	struct ifaddr *ifa, *best;
883 
884 	NET_EPOCH_ASSERT();
885 
886 	if (af >= AF_MAX)
887 		return (NULL);
888 	best = NULL;
889 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
890 		if (ifa->ifa_addr->sa_family == af &&
891 		    (best == NULL || ifa_preferred(best, ifa)))
892 			best = ifa;
893 	}
894 	if (best != NULL)
895 		ifa_ref(best);
896 	return (best);
897 }
898 
899 static void
900 carp_send_ad_locked(struct carp_softc *sc)
901 {
902 	struct carp_header ch;
903 	struct timeval tv;
904 	struct ifaddr *ifa;
905 	struct carp_header *ch_ptr;
906 	struct mbuf *m;
907 	int len, advskew;
908 
909 	CARP_LOCK_ASSERT(sc);
910 
911 	advskew = DEMOTE_ADVSKEW(sc);
912 	tv.tv_sec = sc->sc_advbase;
913 	tv.tv_usec = advskew * 1000000 / 256;
914 
915 	ch.carp_version = CARP_VERSION;
916 	ch.carp_type = CARP_ADVERTISEMENT;
917 	ch.carp_vhid = sc->sc_vhid;
918 	ch.carp_advbase = sc->sc_advbase;
919 	ch.carp_advskew = advskew;
920 	ch.carp_authlen = 7;	/* XXX DEFINE */
921 	ch.carp_pad1 = 0;	/* must be zero */
922 	ch.carp_cksum = 0;
923 
924 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
925 
926 #ifdef INET
927 	if (sc->sc_naddrs) {
928 		struct ip *ip;
929 
930 		m = m_gethdr(M_NOWAIT, MT_DATA);
931 		if (m == NULL) {
932 			CARPSTATS_INC(carps_onomem);
933 			goto resched;
934 		}
935 		len = sizeof(*ip) + sizeof(ch);
936 		m->m_pkthdr.len = len;
937 		m->m_pkthdr.rcvif = NULL;
938 		m->m_len = len;
939 		M_ALIGN(m, m->m_len);
940 		m->m_flags |= M_MCAST;
941 		ip = mtod(m, struct ip *);
942 		ip->ip_v = IPVERSION;
943 		ip->ip_hl = sizeof(*ip) >> 2;
944 		ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
945 		ip->ip_len = htons(len);
946 		ip->ip_off = htons(IP_DF);
947 		ip->ip_ttl = CARP_DFLTTL;
948 		ip->ip_p = IPPROTO_CARP;
949 		ip->ip_sum = 0;
950 		ip_fillid(ip);
951 
952 		ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
953 		if (ifa != NULL) {
954 			ip->ip_src.s_addr =
955 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
956 			ifa_free(ifa);
957 		} else
958 			ip->ip_src.s_addr = 0;
959 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
960 
961 		ch_ptr = (struct carp_header *)(&ip[1]);
962 		bcopy(&ch, ch_ptr, sizeof(ch));
963 		if (carp_prepare_ad(m, sc, ch_ptr))
964 			goto resched;
965 
966 		m->m_data += sizeof(*ip);
967 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
968 		m->m_data -= sizeof(*ip);
969 
970 		CARPSTATS_INC(carps_opackets);
971 
972 		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
973 		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
974 	}
975 #endif /* INET */
976 #ifdef INET6
977 	if (sc->sc_naddrs6) {
978 		struct ip6_hdr *ip6;
979 
980 		m = m_gethdr(M_NOWAIT, MT_DATA);
981 		if (m == NULL) {
982 			CARPSTATS_INC(carps_onomem);
983 			goto resched;
984 		}
985 		len = sizeof(*ip6) + sizeof(ch);
986 		m->m_pkthdr.len = len;
987 		m->m_pkthdr.rcvif = NULL;
988 		m->m_len = len;
989 		M_ALIGN(m, m->m_len);
990 		m->m_flags |= M_MCAST;
991 		ip6 = mtod(m, struct ip6_hdr *);
992 		bzero(ip6, sizeof(*ip6));
993 		ip6->ip6_vfc |= IPV6_VERSION;
994 		/* Traffic class isn't defined in ip6 struct instead
995 		 * it gets offset into flowid field */
996 		ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
997 		    IPTOS_DSCP_OFFSET));
998 		ip6->ip6_hlim = CARP_DFLTTL;
999 		ip6->ip6_nxt = IPPROTO_CARP;
1000 
1001 		/* set the source address */
1002 		ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1003 		if (ifa != NULL) {
1004 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1005 			    sizeof(struct in6_addr));
1006 			ifa_free(ifa);
1007 		} else
1008 			/* This should never happen with IPv6. */
1009 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1010 
1011 		/* Set the multicast destination. */
1012 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1013 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1014 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1015 			m_freem(m);
1016 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1017 			goto resched;
1018 		}
1019 
1020 		ch_ptr = (struct carp_header *)(&ip6[1]);
1021 		bcopy(&ch, ch_ptr, sizeof(ch));
1022 		if (carp_prepare_ad(m, sc, ch_ptr))
1023 			goto resched;
1024 
1025 		m->m_data += sizeof(*ip6);
1026 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1027 		m->m_data -= sizeof(*ip6);
1028 
1029 		CARPSTATS_INC(carps_opackets6);
1030 
1031 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1032 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1033 	}
1034 #endif /* INET6 */
1035 
1036 resched:
1037 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1038 }
1039 
1040 static void
1041 carp_addroute(struct carp_softc *sc)
1042 {
1043 	struct ifaddr *ifa;
1044 
1045 	CARP_FOREACH_IFA(sc, ifa)
1046 		carp_ifa_addroute(ifa);
1047 }
1048 
1049 static void
1050 carp_ifa_addroute(struct ifaddr *ifa)
1051 {
1052 
1053 	switch (ifa->ifa_addr->sa_family) {
1054 #ifdef INET
1055 	case AF_INET:
1056 		in_addprefix(ifatoia(ifa), RTF_UP);
1057 		ifa_add_loopback_route(ifa,
1058 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1059 		break;
1060 #endif
1061 #ifdef INET6
1062 	case AF_INET6:
1063 		ifa_add_loopback_route(ifa,
1064 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1065 		nd6_add_ifa_lle(ifatoia6(ifa));
1066 		break;
1067 #endif
1068 	}
1069 }
1070 
1071 static void
1072 carp_delroute(struct carp_softc *sc)
1073 {
1074 	struct ifaddr *ifa;
1075 
1076 	CARP_FOREACH_IFA(sc, ifa)
1077 		carp_ifa_delroute(ifa);
1078 }
1079 
1080 static void
1081 carp_ifa_delroute(struct ifaddr *ifa)
1082 {
1083 
1084 	switch (ifa->ifa_addr->sa_family) {
1085 #ifdef INET
1086 	case AF_INET:
1087 		ifa_del_loopback_route(ifa,
1088 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1089 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1090 		break;
1091 #endif
1092 #ifdef INET6
1093 	case AF_INET6:
1094 		ifa_del_loopback_route(ifa,
1095 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1096 		nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1097 		break;
1098 #endif
1099 	}
1100 }
1101 
1102 int
1103 carp_master(struct ifaddr *ifa)
1104 {
1105 	struct carp_softc *sc = ifa->ifa_carp;
1106 
1107 	return (sc->sc_state == MASTER);
1108 }
1109 
1110 #ifdef INET
1111 /*
1112  * Broadcast a gratuitous ARP request containing
1113  * the virtual router MAC address for each IP address
1114  * associated with the virtual router.
1115  */
1116 static void
1117 carp_send_arp(struct carp_softc *sc)
1118 {
1119 	struct ifaddr *ifa;
1120 	struct in_addr addr;
1121 
1122 	CARP_FOREACH_IFA(sc, ifa) {
1123 		if (ifa->ifa_addr->sa_family != AF_INET)
1124 			continue;
1125 		addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1126 		arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1127 	}
1128 }
1129 
1130 int
1131 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1132 {
1133 	struct carp_softc *sc = ifa->ifa_carp;
1134 
1135 	if (sc->sc_state == MASTER) {
1136 		*enaddr = LLADDR(&sc->sc_addr);
1137 		return (1);
1138 	}
1139 
1140 	return (0);
1141 }
1142 #endif
1143 
1144 #ifdef INET6
1145 static void
1146 carp_send_na(struct carp_softc *sc)
1147 {
1148 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1149 	struct ifaddr *ifa;
1150 	struct in6_addr *in6;
1151 
1152 	CARP_FOREACH_IFA(sc, ifa) {
1153 		if (ifa->ifa_addr->sa_family != AF_INET6)
1154 			continue;
1155 
1156 		in6 = IFA_IN6(ifa);
1157 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1158 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1159 		DELAY(1000);	/* XXX */
1160 	}
1161 }
1162 
1163 /*
1164  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1165  * matches and is not a carp address.  Returns NULL otherwise.
1166  */
1167 struct ifaddr *
1168 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1169 {
1170 	struct ifaddr *ifa;
1171 
1172 	NET_EPOCH_ASSERT();
1173 
1174 	ifa = NULL;
1175 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1176 		if (ifa->ifa_addr->sa_family != AF_INET6)
1177 			continue;
1178 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1179 			continue;
1180 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1181 			ifa = NULL;
1182 		else
1183 			ifa_ref(ifa);
1184 		break;
1185 	}
1186 
1187 	return (ifa);
1188 }
1189 
1190 caddr_t
1191 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1192 {
1193 	struct ifaddr *ifa;
1194 
1195 	NET_EPOCH_ASSERT();
1196 
1197 	IFNET_FOREACH_IFA(ifp, ifa)
1198 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1199 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1200 			struct carp_softc *sc = ifa->ifa_carp;
1201 			struct m_tag *mtag;
1202 
1203 			mtag = m_tag_get(PACKET_TAG_CARP,
1204 			    sizeof(struct carp_softc *), M_NOWAIT);
1205 			if (mtag == NULL)
1206 				/* Better a bit than nothing. */
1207 				return (LLADDR(&sc->sc_addr));
1208 
1209 			bcopy(&sc, mtag + 1, sizeof(sc));
1210 			m_tag_prepend(m, mtag);
1211 
1212 			return (LLADDR(&sc->sc_addr));
1213 		}
1214 
1215 	return (NULL);
1216 }
1217 #endif /* INET6 */
1218 
1219 int
1220 carp_forus(struct ifnet *ifp, u_char *dhost)
1221 {
1222 	struct carp_softc *sc;
1223 	uint8_t *ena = dhost;
1224 
1225 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1226 		return (0);
1227 
1228 	CIF_LOCK(ifp->if_carp);
1229 	IFNET_FOREACH_CARP(ifp, sc) {
1230 		CARP_LOCK(sc);
1231 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1232 		    ETHER_ADDR_LEN)) {
1233 			CARP_UNLOCK(sc);
1234 			CIF_UNLOCK(ifp->if_carp);
1235 			return (1);
1236 		}
1237 		CARP_UNLOCK(sc);
1238 	}
1239 	CIF_UNLOCK(ifp->if_carp);
1240 
1241 	return (0);
1242 }
1243 
1244 /* Master down timeout event, executed in callout context. */
1245 static void
1246 carp_master_down(void *v)
1247 {
1248 	struct carp_softc *sc = v;
1249 
1250 	CARP_LOCK_ASSERT(sc);
1251 
1252 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1253 	if (sc->sc_state == BACKUP) {
1254 		carp_master_down_locked(sc, "master timed out");
1255 	}
1256 	CURVNET_RESTORE();
1257 
1258 	CARP_UNLOCK(sc);
1259 }
1260 
1261 static void
1262 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1263 {
1264 
1265 	CARP_LOCK_ASSERT(sc);
1266 
1267 	switch (sc->sc_state) {
1268 	case BACKUP:
1269 		carp_set_state(sc, MASTER, reason);
1270 		carp_send_ad_locked(sc);
1271 #ifdef INET
1272 		carp_send_arp(sc);
1273 #endif
1274 #ifdef INET6
1275 		carp_send_na(sc);
1276 #endif
1277 		carp_setrun(sc, 0);
1278 		carp_addroute(sc);
1279 		break;
1280 	case INIT:
1281 	case MASTER:
1282 #ifdef INVARIANTS
1283 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1284 		    sc->sc_vhid,
1285 		    sc->sc_carpdev->if_xname,
1286 		    sc->sc_state ? "MASTER" : "INIT");
1287 #endif
1288 		break;
1289 	}
1290 }
1291 
1292 /*
1293  * When in backup state, af indicates whether to reset the master down timer
1294  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1295  */
1296 static void
1297 carp_setrun(struct carp_softc *sc, sa_family_t af)
1298 {
1299 	struct timeval tv;
1300 
1301 	CARP_LOCK_ASSERT(sc);
1302 
1303 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1304 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1305 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1306 	    !V_carp_allow)
1307 		return;
1308 
1309 	switch (sc->sc_state) {
1310 	case INIT:
1311 		carp_set_state(sc, BACKUP, "initialization complete");
1312 		carp_setrun(sc, 0);
1313 		break;
1314 	case BACKUP:
1315 		callout_stop(&sc->sc_ad_tmo);
1316 		tv.tv_sec = 3 * sc->sc_advbase;
1317 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1318 		switch (af) {
1319 #ifdef INET
1320 		case AF_INET:
1321 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1322 			    carp_master_down, sc);
1323 			break;
1324 #endif
1325 #ifdef INET6
1326 		case AF_INET6:
1327 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1328 			    carp_master_down, sc);
1329 			break;
1330 #endif
1331 		default:
1332 #ifdef INET
1333 			if (sc->sc_naddrs)
1334 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1335 				    carp_master_down, sc);
1336 #endif
1337 #ifdef INET6
1338 			if (sc->sc_naddrs6)
1339 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1340 				    carp_master_down, sc);
1341 #endif
1342 			break;
1343 		}
1344 		break;
1345 	case MASTER:
1346 		tv.tv_sec = sc->sc_advbase;
1347 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1348 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1349 		    carp_send_ad, sc);
1350 		break;
1351 	}
1352 }
1353 
1354 /*
1355  * Setup multicast structures.
1356  */
1357 static int
1358 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1359 {
1360 	struct ifnet *ifp = cif->cif_ifp;
1361 	int error = 0;
1362 
1363 	switch (sa) {
1364 #ifdef INET
1365 	case AF_INET:
1366 	    {
1367 		struct ip_moptions *imo = &cif->cif_imo;
1368 		struct in_mfilter *imf;
1369 		struct in_addr addr;
1370 
1371 		if (ip_mfilter_first(&imo->imo_head) != NULL)
1372 			return (0);
1373 
1374 		imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1375 		ip_mfilter_init(&imo->imo_head);
1376 		imo->imo_multicast_vif = -1;
1377 
1378 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1379 		if ((error = in_joingroup(ifp, &addr, NULL,
1380 		    &imf->imf_inm)) != 0) {
1381 			ip_mfilter_free(imf);
1382 			break;
1383 		}
1384 
1385 		ip_mfilter_insert(&imo->imo_head, imf);
1386 		imo->imo_multicast_ifp = ifp;
1387 		imo->imo_multicast_ttl = CARP_DFLTTL;
1388 		imo->imo_multicast_loop = 0;
1389 		break;
1390 	   }
1391 #endif
1392 #ifdef INET6
1393 	case AF_INET6:
1394 	    {
1395 		struct ip6_moptions *im6o = &cif->cif_im6o;
1396 		struct in6_mfilter *im6f[2];
1397 		struct in6_addr in6;
1398 
1399 		if (ip6_mfilter_first(&im6o->im6o_head))
1400 			return (0);
1401 
1402 		im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1403 		im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1404 
1405 		ip6_mfilter_init(&im6o->im6o_head);
1406 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1407 		im6o->im6o_multicast_ifp = ifp;
1408 
1409 		/* Join IPv6 CARP multicast group. */
1410 		bzero(&in6, sizeof(in6));
1411 		in6.s6_addr16[0] = htons(0xff02);
1412 		in6.s6_addr8[15] = 0x12;
1413 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1414 			ip6_mfilter_free(im6f[0]);
1415 			ip6_mfilter_free(im6f[1]);
1416 			break;
1417 		}
1418 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1419 			ip6_mfilter_free(im6f[0]);
1420 			ip6_mfilter_free(im6f[1]);
1421 			break;
1422 		}
1423 
1424 		/* Join solicited multicast address. */
1425 		bzero(&in6, sizeof(in6));
1426 		in6.s6_addr16[0] = htons(0xff02);
1427 		in6.s6_addr32[1] = 0;
1428 		in6.s6_addr32[2] = htonl(1);
1429 		in6.s6_addr32[3] = 0;
1430 		in6.s6_addr8[12] = 0xff;
1431 
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 
1438 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1439 			in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1440 			ip6_mfilter_free(im6f[0]);
1441 			ip6_mfilter_free(im6f[1]);
1442 			break;
1443 		}
1444 		ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1445 		ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1446 		break;
1447 	    }
1448 #endif
1449 	}
1450 
1451 	return (error);
1452 }
1453 
1454 /*
1455  * Free multicast structures.
1456  */
1457 static void
1458 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1459 {
1460 #ifdef INET
1461 	struct ip_moptions *imo = &cif->cif_imo;
1462 	struct in_mfilter *imf;
1463 #endif
1464 #ifdef INET6
1465 	struct ip6_moptions *im6o = &cif->cif_im6o;
1466 	struct in6_mfilter *im6f;
1467 #endif
1468 	sx_assert(&carp_sx, SA_XLOCKED);
1469 
1470 	switch (sa) {
1471 #ifdef INET
1472 	case AF_INET:
1473 		if (cif->cif_naddrs != 0)
1474 			break;
1475 
1476 		while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1477 			ip_mfilter_remove(&imo->imo_head, imf);
1478 			in_leavegroup(imf->imf_inm, NULL);
1479 			ip_mfilter_free(imf);
1480 		}
1481 		break;
1482 #endif
1483 #ifdef INET6
1484 	case AF_INET6:
1485 		if (cif->cif_naddrs6 != 0)
1486 			break;
1487 
1488 		while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1489 			ip6_mfilter_remove(&im6o->im6o_head, im6f);
1490 			in6_leavegroup(im6f->im6f_in6m, NULL);
1491 			ip6_mfilter_free(im6f);
1492 		}
1493 		break;
1494 #endif
1495 	}
1496 }
1497 
1498 int
1499 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1500 {
1501 	struct m_tag *mtag;
1502 	struct carp_softc *sc;
1503 
1504 	if (!sa)
1505 		return (0);
1506 
1507 	switch (sa->sa_family) {
1508 #ifdef INET
1509 	case AF_INET:
1510 		break;
1511 #endif
1512 #ifdef INET6
1513 	case AF_INET6:
1514 		break;
1515 #endif
1516 	default:
1517 		return (0);
1518 	}
1519 
1520 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1521 	if (mtag == NULL)
1522 		return (0);
1523 
1524 	bcopy(mtag + 1, &sc, sizeof(sc));
1525 
1526 	/* Set the source MAC address to the Virtual Router MAC Address. */
1527 	switch (ifp->if_type) {
1528 	case IFT_ETHER:
1529 	case IFT_BRIDGE:
1530 	case IFT_L2VLAN: {
1531 			struct ether_header *eh;
1532 
1533 			eh = mtod(m, struct ether_header *);
1534 			eh->ether_shost[0] = 0;
1535 			eh->ether_shost[1] = 0;
1536 			eh->ether_shost[2] = 0x5e;
1537 			eh->ether_shost[3] = 0;
1538 			eh->ether_shost[4] = 1;
1539 			eh->ether_shost[5] = sc->sc_vhid;
1540 		}
1541 		break;
1542 	default:
1543 		printf("%s: carp is not supported for the %d interface type\n",
1544 		    ifp->if_xname, ifp->if_type);
1545 		return (EOPNOTSUPP);
1546 	}
1547 
1548 	return (0);
1549 }
1550 
1551 static struct carp_softc*
1552 carp_alloc(struct ifnet *ifp)
1553 {
1554 	struct carp_softc *sc;
1555 	struct carp_if *cif;
1556 
1557 	sx_assert(&carp_sx, SA_XLOCKED);
1558 
1559 	if ((cif = ifp->if_carp) == NULL)
1560 		cif = carp_alloc_if(ifp);
1561 
1562 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1563 
1564 	sc->sc_advbase = CARP_DFLTINTV;
1565 	sc->sc_vhid = -1;	/* required setting */
1566 	sc->sc_init_counter = 1;
1567 	sc->sc_state = INIT;
1568 
1569 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1570 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1571 	sc->sc_carpdev = ifp;
1572 
1573 	CARP_LOCK_INIT(sc);
1574 #ifdef INET
1575 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1576 #endif
1577 #ifdef INET6
1578 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1579 #endif
1580 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1581 
1582 	CIF_LOCK(cif);
1583 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1584 	CIF_UNLOCK(cif);
1585 
1586 	mtx_lock(&carp_mtx);
1587 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1588 	mtx_unlock(&carp_mtx);
1589 
1590 	return (sc);
1591 }
1592 
1593 static void
1594 carp_grow_ifas(struct carp_softc *sc)
1595 {
1596 	struct ifaddr **new;
1597 
1598 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1599 	CARP_LOCK(sc);
1600 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1601 	free(sc->sc_ifas, M_CARP);
1602 	sc->sc_ifas = new;
1603 	sc->sc_ifasiz *= 2;
1604 	CARP_UNLOCK(sc);
1605 }
1606 
1607 static void
1608 carp_destroy(struct carp_softc *sc)
1609 {
1610 	struct ifnet *ifp = sc->sc_carpdev;
1611 	struct carp_if *cif = ifp->if_carp;
1612 
1613 	sx_assert(&carp_sx, SA_XLOCKED);
1614 
1615 	if (sc->sc_suppress)
1616 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1617 	CARP_UNLOCK(sc);
1618 
1619 	CIF_LOCK(cif);
1620 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1621 	CIF_UNLOCK(cif);
1622 
1623 	mtx_lock(&carp_mtx);
1624 	LIST_REMOVE(sc, sc_next);
1625 	mtx_unlock(&carp_mtx);
1626 
1627 	callout_drain(&sc->sc_ad_tmo);
1628 #ifdef INET
1629 	callout_drain(&sc->sc_md_tmo);
1630 #endif
1631 #ifdef INET6
1632 	callout_drain(&sc->sc_md6_tmo);
1633 #endif
1634 	CARP_LOCK_DESTROY(sc);
1635 
1636 	free(sc->sc_ifas, M_CARP);
1637 	free(sc, M_CARP);
1638 }
1639 
1640 static struct carp_if*
1641 carp_alloc_if(struct ifnet *ifp)
1642 {
1643 	struct carp_if *cif;
1644 	int error;
1645 
1646 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1647 
1648 	if ((error = ifpromisc(ifp, 1)) != 0)
1649 		printf("%s: ifpromisc(%s) failed: %d\n",
1650 		    __func__, ifp->if_xname, error);
1651 	else
1652 		cif->cif_flags |= CIF_PROMISC;
1653 
1654 	CIF_LOCK_INIT(cif);
1655 	cif->cif_ifp = ifp;
1656 	TAILQ_INIT(&cif->cif_vrs);
1657 
1658 	IF_ADDR_WLOCK(ifp);
1659 	ifp->if_carp = cif;
1660 	if_ref(ifp);
1661 	IF_ADDR_WUNLOCK(ifp);
1662 
1663 	return (cif);
1664 }
1665 
1666 static void
1667 carp_free_if(struct carp_if *cif)
1668 {
1669 	struct ifnet *ifp = cif->cif_ifp;
1670 
1671 	CIF_LOCK_ASSERT(cif);
1672 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1673 	    __func__));
1674 
1675 	IF_ADDR_WLOCK(ifp);
1676 	ifp->if_carp = NULL;
1677 	IF_ADDR_WUNLOCK(ifp);
1678 
1679 	CIF_LOCK_DESTROY(cif);
1680 
1681 	if (cif->cif_flags & CIF_PROMISC)
1682 		ifpromisc(ifp, 0);
1683 	if_rele(ifp);
1684 
1685 	free(cif, M_CARP);
1686 }
1687 
1688 static void
1689 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1690 {
1691 
1692 	CARP_LOCK(sc);
1693 	carpr->carpr_state = sc->sc_state;
1694 	carpr->carpr_vhid = sc->sc_vhid;
1695 	carpr->carpr_advbase = sc->sc_advbase;
1696 	carpr->carpr_advskew = sc->sc_advskew;
1697 	if (priv)
1698 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1699 	else
1700 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1701 	CARP_UNLOCK(sc);
1702 }
1703 
1704 int
1705 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1706 {
1707 	struct carpreq carpr;
1708 	struct ifnet *ifp;
1709 	struct carp_softc *sc = NULL;
1710 	int error = 0, locked = 0;
1711 
1712 	if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1713 		return (error);
1714 
1715 	ifp = ifunit_ref(ifr->ifr_name);
1716 	if (ifp == NULL)
1717 		return (ENXIO);
1718 
1719 	switch (ifp->if_type) {
1720 	case IFT_ETHER:
1721 	case IFT_L2VLAN:
1722 	case IFT_BRIDGE:
1723 		break;
1724 	default:
1725 		error = EOPNOTSUPP;
1726 		goto out;
1727 	}
1728 
1729 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1730 		error = EADDRNOTAVAIL;
1731 		goto out;
1732 	}
1733 
1734 	sx_xlock(&carp_sx);
1735 	switch (cmd) {
1736 	case SIOCSVH:
1737 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1738 			break;
1739 		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1740 		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1741 			error = EINVAL;
1742 			break;
1743 		}
1744 
1745 		if (ifp->if_carp) {
1746 			IFNET_FOREACH_CARP(ifp, sc)
1747 				if (sc->sc_vhid == carpr.carpr_vhid)
1748 					break;
1749 		}
1750 		if (sc == NULL) {
1751 			sc = carp_alloc(ifp);
1752 			CARP_LOCK(sc);
1753 			sc->sc_vhid = carpr.carpr_vhid;
1754 			LLADDR(&sc->sc_addr)[0] = 0;
1755 			LLADDR(&sc->sc_addr)[1] = 0;
1756 			LLADDR(&sc->sc_addr)[2] = 0x5e;
1757 			LLADDR(&sc->sc_addr)[3] = 0;
1758 			LLADDR(&sc->sc_addr)[4] = 1;
1759 			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1760 		} else
1761 			CARP_LOCK(sc);
1762 		locked = 1;
1763 		if (carpr.carpr_advbase > 0) {
1764 			if (carpr.carpr_advbase > 255 ||
1765 			    carpr.carpr_advbase < CARP_DFLTINTV) {
1766 				error = EINVAL;
1767 				break;
1768 			}
1769 			sc->sc_advbase = carpr.carpr_advbase;
1770 		}
1771 		if (carpr.carpr_advskew >= 255) {
1772 			error = EINVAL;
1773 			break;
1774 		}
1775 		sc->sc_advskew = carpr.carpr_advskew;
1776 		if (carpr.carpr_key[0] != '\0') {
1777 			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1778 			carp_hmac_prepare(sc);
1779 		}
1780 		if (sc->sc_state != INIT &&
1781 		    carpr.carpr_state != sc->sc_state) {
1782 			switch (carpr.carpr_state) {
1783 			case BACKUP:
1784 				callout_stop(&sc->sc_ad_tmo);
1785 				carp_set_state(sc, BACKUP,
1786 				    "user requested via ifconfig");
1787 				carp_setrun(sc, 0);
1788 				carp_delroute(sc);
1789 				break;
1790 			case MASTER:
1791 				carp_master_down_locked(sc,
1792 				    "user requested via ifconfig");
1793 				break;
1794 			default:
1795 				break;
1796 			}
1797 		}
1798 		break;
1799 
1800 	case SIOCGVH:
1801 	    {
1802 		int priveleged;
1803 
1804 		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1805 			error = EINVAL;
1806 			break;
1807 		}
1808 		if (carpr.carpr_count < 1) {
1809 			error = EMSGSIZE;
1810 			break;
1811 		}
1812 		if (ifp->if_carp == NULL) {
1813 			error = ENOENT;
1814 			break;
1815 		}
1816 
1817 		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1818 		if (carpr.carpr_vhid != 0) {
1819 			IFNET_FOREACH_CARP(ifp, sc)
1820 				if (sc->sc_vhid == carpr.carpr_vhid)
1821 					break;
1822 			if (sc == NULL) {
1823 				error = ENOENT;
1824 				break;
1825 			}
1826 			carp_carprcp(&carpr, sc, priveleged);
1827 			error = copyout(&carpr, ifr_data_get_ptr(ifr),
1828 			    sizeof(carpr));
1829 		} else  {
1830 			int i, count;
1831 
1832 			count = 0;
1833 			IFNET_FOREACH_CARP(ifp, sc)
1834 				count++;
1835 
1836 			if (count > carpr.carpr_count) {
1837 				CIF_UNLOCK(ifp->if_carp);
1838 				error = EMSGSIZE;
1839 				break;
1840 			}
1841 
1842 			i = 0;
1843 			IFNET_FOREACH_CARP(ifp, sc) {
1844 				carp_carprcp(&carpr, sc, priveleged);
1845 				carpr.carpr_count = count;
1846 				error = copyout(&carpr,
1847 				    (caddr_t)ifr_data_get_ptr(ifr) +
1848 				    (i * sizeof(carpr)), sizeof(carpr));
1849 				if (error) {
1850 					CIF_UNLOCK(ifp->if_carp);
1851 					break;
1852 				}
1853 				i++;
1854 			}
1855 		}
1856 		break;
1857 	    }
1858 	default:
1859 		error = EINVAL;
1860 	}
1861 	sx_xunlock(&carp_sx);
1862 
1863 out:
1864 	if (locked)
1865 		CARP_UNLOCK(sc);
1866 	if_rele(ifp);
1867 
1868 	return (error);
1869 }
1870 
1871 static int
1872 carp_get_vhid(struct ifaddr *ifa)
1873 {
1874 
1875 	if (ifa == NULL || ifa->ifa_carp == NULL)
1876 		return (0);
1877 
1878 	return (ifa->ifa_carp->sc_vhid);
1879 }
1880 
1881 int
1882 carp_attach(struct ifaddr *ifa, int vhid)
1883 {
1884 	struct ifnet *ifp = ifa->ifa_ifp;
1885 	struct carp_if *cif = ifp->if_carp;
1886 	struct carp_softc *sc;
1887 	int index, error;
1888 
1889 	KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1890 
1891 	switch (ifa->ifa_addr->sa_family) {
1892 #ifdef INET
1893 	case AF_INET:
1894 #endif
1895 #ifdef INET6
1896 	case AF_INET6:
1897 #endif
1898 		break;
1899 	default:
1900 		return (EPROTOTYPE);
1901 	}
1902 
1903 	sx_xlock(&carp_sx);
1904 	if (ifp->if_carp == NULL) {
1905 		sx_xunlock(&carp_sx);
1906 		return (ENOPROTOOPT);
1907 	}
1908 
1909 	IFNET_FOREACH_CARP(ifp, sc)
1910 		if (sc->sc_vhid == vhid)
1911 			break;
1912 	if (sc == NULL) {
1913 		sx_xunlock(&carp_sx);
1914 		return (ENOENT);
1915 	}
1916 
1917 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1918 	if (error) {
1919 		CIF_FREE(cif);
1920 		sx_xunlock(&carp_sx);
1921 		return (error);
1922 	}
1923 
1924 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1925 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1926 		carp_grow_ifas(sc);
1927 
1928 	switch (ifa->ifa_addr->sa_family) {
1929 #ifdef INET
1930 	case AF_INET:
1931 		cif->cif_naddrs++;
1932 		sc->sc_naddrs++;
1933 		break;
1934 #endif
1935 #ifdef INET6
1936 	case AF_INET6:
1937 		cif->cif_naddrs6++;
1938 		sc->sc_naddrs6++;
1939 		break;
1940 #endif
1941 	}
1942 
1943 	ifa_ref(ifa);
1944 
1945 	CARP_LOCK(sc);
1946 	sc->sc_ifas[index - 1] = ifa;
1947 	ifa->ifa_carp = sc;
1948 	carp_hmac_prepare(sc);
1949 	carp_sc_state(sc);
1950 	CARP_UNLOCK(sc);
1951 
1952 	sx_xunlock(&carp_sx);
1953 
1954 	return (0);
1955 }
1956 
1957 void
1958 carp_detach(struct ifaddr *ifa, bool keep_cif)
1959 {
1960 	struct ifnet *ifp = ifa->ifa_ifp;
1961 	struct carp_if *cif = ifp->if_carp;
1962 	struct carp_softc *sc = ifa->ifa_carp;
1963 	int i, index;
1964 
1965 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1966 
1967 	sx_xlock(&carp_sx);
1968 
1969 	CARP_LOCK(sc);
1970 	/* Shift array. */
1971 	index = sc->sc_naddrs + sc->sc_naddrs6;
1972 	for (i = 0; i < index; i++)
1973 		if (sc->sc_ifas[i] == ifa)
1974 			break;
1975 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1976 	for (; i < index - 1; i++)
1977 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1978 	sc->sc_ifas[index - 1] = NULL;
1979 
1980 	switch (ifa->ifa_addr->sa_family) {
1981 #ifdef INET
1982 	case AF_INET:
1983 		cif->cif_naddrs--;
1984 		sc->sc_naddrs--;
1985 		break;
1986 #endif
1987 #ifdef INET6
1988 	case AF_INET6:
1989 		cif->cif_naddrs6--;
1990 		sc->sc_naddrs6--;
1991 		break;
1992 #endif
1993 	}
1994 
1995 	carp_ifa_delroute(ifa);
1996 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
1997 
1998 	ifa->ifa_carp = NULL;
1999 	ifa_free(ifa);
2000 
2001 	carp_hmac_prepare(sc);
2002 	carp_sc_state(sc);
2003 
2004 	if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2005 		carp_destroy(sc);
2006 	else
2007 		CARP_UNLOCK(sc);
2008 
2009 	if (!keep_cif)
2010 		CIF_FREE(cif);
2011 
2012 	sx_xunlock(&carp_sx);
2013 }
2014 
2015 static void
2016 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2017 {
2018 
2019 	CARP_LOCK_ASSERT(sc);
2020 
2021 	if (sc->sc_state != state) {
2022 		const char *carp_states[] = { CARP_STATES };
2023 		char subsys[IFNAMSIZ+5];
2024 
2025 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2026 		    sc->sc_carpdev->if_xname);
2027 
2028 		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2029 		    carp_states[sc->sc_state], carp_states[state], reason);
2030 
2031 		sc->sc_state = state;
2032 
2033 		devctl_notify("CARP", subsys, carp_states[state], NULL);
2034 	}
2035 }
2036 
2037 static void
2038 carp_linkstate(struct ifnet *ifp)
2039 {
2040 	struct carp_softc *sc;
2041 
2042 	CIF_LOCK(ifp->if_carp);
2043 	IFNET_FOREACH_CARP(ifp, sc) {
2044 		CARP_LOCK(sc);
2045 		carp_sc_state(sc);
2046 		CARP_UNLOCK(sc);
2047 	}
2048 	CIF_UNLOCK(ifp->if_carp);
2049 }
2050 
2051 static void
2052 carp_sc_state(struct carp_softc *sc)
2053 {
2054 
2055 	CARP_LOCK_ASSERT(sc);
2056 
2057 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2058 	    !(sc->sc_carpdev->if_flags & IFF_UP) ||
2059 	    !V_carp_allow) {
2060 		callout_stop(&sc->sc_ad_tmo);
2061 #ifdef INET
2062 		callout_stop(&sc->sc_md_tmo);
2063 #endif
2064 #ifdef INET6
2065 		callout_stop(&sc->sc_md6_tmo);
2066 #endif
2067 		carp_set_state(sc, INIT, "hardware interface down");
2068 		carp_setrun(sc, 0);
2069 		if (!sc->sc_suppress)
2070 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2071 		sc->sc_suppress = 1;
2072 	} else {
2073 		carp_set_state(sc, INIT, "hardware interface up");
2074 		carp_setrun(sc, 0);
2075 		if (sc->sc_suppress)
2076 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2077 		sc->sc_suppress = 0;
2078 	}
2079 }
2080 
2081 static void
2082 carp_demote_adj(int adj, char *reason)
2083 {
2084 	atomic_add_int(&V_carp_demotion, adj);
2085 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2086 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2087 }
2088 
2089 static int
2090 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2091 {
2092 	int new, error;
2093 	struct carp_softc *sc;
2094 
2095 	new = V_carp_allow;
2096 	error = sysctl_handle_int(oidp, &new, 0, req);
2097 	if (error || !req->newptr)
2098 		return (error);
2099 
2100 	if (V_carp_allow != new) {
2101 		V_carp_allow = new;
2102 
2103 		mtx_lock(&carp_mtx);
2104 		LIST_FOREACH(sc, &carp_list, sc_next) {
2105 			CARP_LOCK(sc);
2106 			if (curvnet == sc->sc_carpdev->if_vnet)
2107 				carp_sc_state(sc);
2108 			CARP_UNLOCK(sc);
2109 		}
2110 		mtx_unlock(&carp_mtx);
2111 	}
2112 
2113 	return (0);
2114 }
2115 
2116 static int
2117 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2118 {
2119 	int new, error;
2120 
2121 	new = V_carp_dscp;
2122 	error = sysctl_handle_int(oidp, &new, 0, req);
2123 	if (error || !req->newptr)
2124 		return (error);
2125 
2126 	if (new < 0 || new > 63)
2127 		return (EINVAL);
2128 
2129 	V_carp_dscp = new;
2130 
2131 	return (0);
2132 }
2133 
2134 static int
2135 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2136 {
2137 	int new, error;
2138 
2139 	new = V_carp_demotion;
2140 	error = sysctl_handle_int(oidp, &new, 0, req);
2141 	if (error || !req->newptr)
2142 		return (error);
2143 
2144 	carp_demote_adj(new, "sysctl");
2145 
2146 	return (0);
2147 }
2148 
2149 #ifdef INET
2150 extern  struct domain inetdomain;
2151 static struct protosw in_carp_protosw = {
2152 	.pr_type =		SOCK_RAW,
2153 	.pr_domain =		&inetdomain,
2154 	.pr_protocol =		IPPROTO_CARP,
2155 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2156 	.pr_input =		carp_input,
2157 	.pr_output =		rip_output,
2158 	.pr_ctloutput =		rip_ctloutput,
2159 	.pr_usrreqs =		&rip_usrreqs
2160 };
2161 #endif
2162 
2163 #ifdef INET6
2164 extern	struct domain inet6domain;
2165 static struct protosw in6_carp_protosw = {
2166 	.pr_type =		SOCK_RAW,
2167 	.pr_domain =		&inet6domain,
2168 	.pr_protocol =		IPPROTO_CARP,
2169 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2170 	.pr_input =		carp6_input,
2171 	.pr_output =		rip6_output,
2172 	.pr_ctloutput =		rip6_ctloutput,
2173 	.pr_usrreqs =		&rip6_usrreqs
2174 };
2175 #endif
2176 
2177 static void
2178 carp_mod_cleanup(void)
2179 {
2180 
2181 #ifdef INET
2182 	if (proto_reg[CARP_INET] == 0) {
2183 		(void)ipproto_unregister(IPPROTO_CARP);
2184 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2185 		proto_reg[CARP_INET] = -1;
2186 	}
2187 	carp_iamatch_p = NULL;
2188 #endif
2189 #ifdef INET6
2190 	if (proto_reg[CARP_INET6] == 0) {
2191 		(void)ip6proto_unregister(IPPROTO_CARP);
2192 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2193 		proto_reg[CARP_INET6] = -1;
2194 	}
2195 	carp_iamatch6_p = NULL;
2196 	carp_macmatch6_p = NULL;
2197 #endif
2198 	carp_ioctl_p = NULL;
2199 	carp_attach_p = NULL;
2200 	carp_detach_p = NULL;
2201 	carp_get_vhid_p = NULL;
2202 	carp_linkstate_p = NULL;
2203 	carp_forus_p = NULL;
2204 	carp_output_p = NULL;
2205 	carp_demote_adj_p = NULL;
2206 	carp_master_p = NULL;
2207 	mtx_unlock(&carp_mtx);
2208 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2209 	mtx_destroy(&carp_mtx);
2210 	sx_destroy(&carp_sx);
2211 }
2212 
2213 static int
2214 carp_mod_load(void)
2215 {
2216 	int err;
2217 
2218 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2219 	sx_init(&carp_sx, "carp_sx");
2220 	LIST_INIT(&carp_list);
2221 	carp_get_vhid_p = carp_get_vhid;
2222 	carp_forus_p = carp_forus;
2223 	carp_output_p = carp_output;
2224 	carp_linkstate_p = carp_linkstate;
2225 	carp_ioctl_p = carp_ioctl;
2226 	carp_attach_p = carp_attach;
2227 	carp_detach_p = carp_detach;
2228 	carp_demote_adj_p = carp_demote_adj;
2229 	carp_master_p = carp_master;
2230 #ifdef INET6
2231 	carp_iamatch6_p = carp_iamatch6;
2232 	carp_macmatch6_p = carp_macmatch6;
2233 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2234 	    (struct protosw *)&in6_carp_protosw);
2235 	if (proto_reg[CARP_INET6]) {
2236 		printf("carp: error %d attaching to PF_INET6\n",
2237 		    proto_reg[CARP_INET6]);
2238 		carp_mod_cleanup();
2239 		return (proto_reg[CARP_INET6]);
2240 	}
2241 	err = ip6proto_register(IPPROTO_CARP);
2242 	if (err) {
2243 		printf("carp: error %d registering with INET6\n", err);
2244 		carp_mod_cleanup();
2245 		return (err);
2246 	}
2247 #endif
2248 #ifdef INET
2249 	carp_iamatch_p = carp_iamatch;
2250 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2251 	if (proto_reg[CARP_INET]) {
2252 		printf("carp: error %d attaching to PF_INET\n",
2253 		    proto_reg[CARP_INET]);
2254 		carp_mod_cleanup();
2255 		return (proto_reg[CARP_INET]);
2256 	}
2257 	err = ipproto_register(IPPROTO_CARP);
2258 	if (err) {
2259 		printf("carp: error %d registering with INET\n", err);
2260 		carp_mod_cleanup();
2261 		return (err);
2262 	}
2263 #endif
2264 	return (0);
2265 }
2266 
2267 static int
2268 carp_modevent(module_t mod, int type, void *data)
2269 {
2270 	switch (type) {
2271 	case MOD_LOAD:
2272 		return carp_mod_load();
2273 		/* NOTREACHED */
2274 	case MOD_UNLOAD:
2275 		mtx_lock(&carp_mtx);
2276 		if (LIST_EMPTY(&carp_list))
2277 			carp_mod_cleanup();
2278 		else {
2279 			mtx_unlock(&carp_mtx);
2280 			return (EBUSY);
2281 		}
2282 		break;
2283 
2284 	default:
2285 		return (EINVAL);
2286 	}
2287 
2288 	return (0);
2289 }
2290 
2291 static moduledata_t carp_mod = {
2292 	"carp",
2293 	carp_modevent,
2294 	0
2295 };
2296 
2297 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2298