xref: /freebsd/sys/netinet/ip_carp.c (revision 9af6c78cd43b18e169f10802142c61638bd62bed)
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 	m = m_pullup(m, *offp + sizeof(*ch));
571 	if (m == NULL) {
572 		CARPSTATS_INC(carps_badlen);
573 		CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
574 		return (IPPROTO_DONE);
575 	}
576 	ch = (struct carp_header *)(mtod(m, caddr_t) + *offp);
577 
578 
579 	/* verify the CARP checksum */
580 	m->m_data += *offp;
581 	if (in_cksum(m, sizeof(*ch))) {
582 		CARPSTATS_INC(carps_badsum);
583 		CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
584 		    m->m_pkthdr.rcvif->if_xname);
585 		m_freem(m);
586 		return (IPPROTO_DONE);
587 	}
588 	m->m_data -= *offp;
589 
590 	carp_input_c(m, ch, AF_INET6);
591 	return (IPPROTO_DONE);
592 }
593 #endif /* INET6 */
594 
595 /*
596  * This routine should not be necessary at all, but some switches
597  * (VMWare ESX vswitches) can echo our own packets back at us,
598  * and we must ignore them or they will cause us to drop out of
599  * MASTER mode.
600  *
601  * We cannot catch all cases of network loops.  Instead, what we
602  * do here is catch any packet that arrives with a carp header
603  * with a VHID of 0, that comes from an address that is our own.
604  * These packets are by definition "from us" (even if they are from
605  * a misconfigured host that is pretending to be us).
606  *
607  * The VHID test is outside this mini-function.
608  */
609 static int
610 carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
611 {
612 #ifdef INET
613 	struct ip *ip4;
614 	struct in_addr in4;
615 #endif
616 #ifdef INET6
617 	struct ip6_hdr *ip6;
618 	struct in6_addr in6;
619 #endif
620 
621 	switch (af) {
622 #ifdef INET
623 	case AF_INET:
624 		ip4 = mtod(m, struct ip *);
625 		in4 = ifatoia(ifa)->ia_addr.sin_addr;
626 		return (in4.s_addr == ip4->ip_src.s_addr);
627 #endif
628 #ifdef INET6
629 	case AF_INET6:
630 		ip6 = mtod(m, struct ip6_hdr *);
631 		in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
632 		return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
633 #endif
634 	default:
635 		break;
636 	}
637 	return (0);
638 }
639 
640 static void
641 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
642 {
643 	struct ifnet *ifp = m->m_pkthdr.rcvif;
644 	struct ifaddr *ifa, *match;
645 	struct carp_softc *sc;
646 	uint64_t tmp_counter;
647 	struct timeval sc_tv, ch_tv;
648 	int error;
649 
650 	NET_EPOCH_ASSERT();
651 
652 	/*
653 	 * Verify that the VHID is valid on the receiving interface.
654 	 *
655 	 * There should be just one match.  If there are none
656 	 * the VHID is not valid and we drop the packet.  If
657 	 * there are multiple VHID matches, take just the first
658 	 * one, for compatibility with previous code.  While we're
659 	 * scanning, check for obvious loops in the network topology
660 	 * (these should never happen, and as noted above, we may
661 	 * miss real loops; this is just a double-check).
662 	 */
663 	error = 0;
664 	match = NULL;
665 	IFNET_FOREACH_IFA(ifp, ifa) {
666 		if (match == NULL && ifa->ifa_carp != NULL &&
667 		    ifa->ifa_addr->sa_family == af &&
668 		    ifa->ifa_carp->sc_vhid == ch->carp_vhid)
669 			match = ifa;
670 		if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
671 			error = ELOOP;
672 	}
673 	ifa = error ? NULL : match;
674 	if (ifa != NULL)
675 		ifa_ref(ifa);
676 
677 	if (ifa == NULL) {
678 		if (error == ELOOP) {
679 			CARP_DEBUG("dropping looped packet on interface %s\n",
680 			    ifp->if_xname);
681 			CARPSTATS_INC(carps_badif);	/* ??? */
682 		} else {
683 			CARPSTATS_INC(carps_badvhid);
684 		}
685 		m_freem(m);
686 		return;
687 	}
688 
689 	/* verify the CARP version. */
690 	if (ch->carp_version != CARP_VERSION) {
691 		CARPSTATS_INC(carps_badver);
692 		CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
693 		    ch->carp_version);
694 		ifa_free(ifa);
695 		m_freem(m);
696 		return;
697 	}
698 
699 	sc = ifa->ifa_carp;
700 	CARP_LOCK(sc);
701 	ifa_free(ifa);
702 
703 	if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
704 		CARPSTATS_INC(carps_badauth);
705 		CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
706 		    sc->sc_vhid, ifp->if_xname);
707 		goto out;
708 	}
709 
710 	tmp_counter = ntohl(ch->carp_counter[0]);
711 	tmp_counter = tmp_counter<<32;
712 	tmp_counter += ntohl(ch->carp_counter[1]);
713 
714 	/* XXX Replay protection goes here */
715 
716 	sc->sc_init_counter = 0;
717 	sc->sc_counter = tmp_counter;
718 
719 	sc_tv.tv_sec = sc->sc_advbase;
720 	sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
721 	ch_tv.tv_sec = ch->carp_advbase;
722 	ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
723 
724 	switch (sc->sc_state) {
725 	case INIT:
726 		break;
727 	case MASTER:
728 		/*
729 		 * If we receive an advertisement from a master who's going to
730 		 * be more frequent than us, go into BACKUP state.
731 		 */
732 		if (timevalcmp(&sc_tv, &ch_tv, >) ||
733 		    timevalcmp(&sc_tv, &ch_tv, ==)) {
734 			callout_stop(&sc->sc_ad_tmo);
735 			carp_set_state(sc, BACKUP,
736 			    "more frequent advertisement received");
737 			carp_setrun(sc, 0);
738 			carp_delroute(sc);
739 		}
740 		break;
741 	case BACKUP:
742 		/*
743 		 * If we're pre-empting masters who advertise slower than us,
744 		 * and this one claims to be slower, treat him as down.
745 		 */
746 		if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
747 			carp_master_down_locked(sc,
748 			    "preempting a slower master");
749 			break;
750 		}
751 
752 		/*
753 		 *  If the master is going to advertise at such a low frequency
754 		 *  that he's guaranteed to time out, we'd might as well just
755 		 *  treat him as timed out now.
756 		 */
757 		sc_tv.tv_sec = sc->sc_advbase * 3;
758 		if (timevalcmp(&sc_tv, &ch_tv, <)) {
759 			carp_master_down_locked(sc, "master will time out");
760 			break;
761 		}
762 
763 		/*
764 		 * Otherwise, we reset the counter and wait for the next
765 		 * advertisement.
766 		 */
767 		carp_setrun(sc, af);
768 		break;
769 	}
770 
771 out:
772 	CARP_UNLOCK(sc);
773 	m_freem(m);
774 }
775 
776 static int
777 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
778 {
779 	struct m_tag *mtag;
780 
781 	if (sc->sc_init_counter) {
782 		/* this could also be seconds since unix epoch */
783 		sc->sc_counter = arc4random();
784 		sc->sc_counter = sc->sc_counter << 32;
785 		sc->sc_counter += arc4random();
786 	} else
787 		sc->sc_counter++;
788 
789 	ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
790 	ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
791 
792 	carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
793 
794 	/* Tag packet for carp_output */
795 	if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
796 	    M_NOWAIT)) == NULL) {
797 		m_freem(m);
798 		CARPSTATS_INC(carps_onomem);
799 		return (ENOMEM);
800 	}
801 	bcopy(&sc, mtag + 1, sizeof(sc));
802 	m_tag_prepend(m, mtag);
803 
804 	return (0);
805 }
806 
807 /*
808  * To avoid LORs and possible recursions this function shouldn't
809  * be called directly, but scheduled via taskqueue.
810  */
811 static void
812 carp_send_ad_all(void *ctx __unused, int pending __unused)
813 {
814 	struct carp_softc *sc;
815 
816 	mtx_lock(&carp_mtx);
817 	LIST_FOREACH(sc, &carp_list, sc_next)
818 		if (sc->sc_state == MASTER) {
819 			CARP_LOCK(sc);
820 			CURVNET_SET(sc->sc_carpdev->if_vnet);
821 			carp_send_ad_locked(sc);
822 			CURVNET_RESTORE();
823 			CARP_UNLOCK(sc);
824 		}
825 	mtx_unlock(&carp_mtx);
826 }
827 
828 /* Send a periodic advertisement, executed in callout context. */
829 static void
830 carp_send_ad(void *v)
831 {
832 	struct carp_softc *sc = v;
833 
834 	CARP_LOCK_ASSERT(sc);
835 	CURVNET_SET(sc->sc_carpdev->if_vnet);
836 	carp_send_ad_locked(sc);
837 	CURVNET_RESTORE();
838 	CARP_UNLOCK(sc);
839 }
840 
841 static void
842 carp_send_ad_error(struct carp_softc *sc, int error)
843 {
844 
845 	if (error) {
846 		if (sc->sc_sendad_errors < INT_MAX)
847 			sc->sc_sendad_errors++;
848 		if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
849 			static const char fmt[] = "send error %d on %s";
850 			char msg[sizeof(fmt) + IFNAMSIZ];
851 
852 			sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
853 			carp_demote_adj(V_carp_senderr_adj, msg);
854 		}
855 		sc->sc_sendad_success = 0;
856 	} else {
857 		if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS &&
858 		    ++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
859 			static const char fmt[] = "send ok on %s";
860 			char msg[sizeof(fmt) + IFNAMSIZ];
861 
862 			sprintf(msg, fmt, sc->sc_carpdev->if_xname);
863 			carp_demote_adj(-V_carp_senderr_adj, msg);
864 			sc->sc_sendad_errors = 0;
865 		} else
866 			sc->sc_sendad_errors = 0;
867 	}
868 }
869 
870 /*
871  * Pick the best ifaddr on the given ifp for sending CARP
872  * advertisements.
873  *
874  * "Best" here is defined by ifa_preferred().  This function is much
875  * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
876  *
877  * (This could be simplified to return the actual address, except that
878  * it has a different format in AF_INET and AF_INET6.)
879  */
880 static struct ifaddr *
881 carp_best_ifa(int af, struct ifnet *ifp)
882 {
883 	struct ifaddr *ifa, *best;
884 
885 	NET_EPOCH_ASSERT();
886 
887 	if (af >= AF_MAX)
888 		return (NULL);
889 	best = NULL;
890 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
891 		if (ifa->ifa_addr->sa_family == af &&
892 		    (best == NULL || ifa_preferred(best, ifa)))
893 			best = ifa;
894 	}
895 	if (best != NULL)
896 		ifa_ref(best);
897 	return (best);
898 }
899 
900 static void
901 carp_send_ad_locked(struct carp_softc *sc)
902 {
903 	struct carp_header ch;
904 	struct timeval tv;
905 	struct ifaddr *ifa;
906 	struct carp_header *ch_ptr;
907 	struct mbuf *m;
908 	int len, advskew;
909 
910 	CARP_LOCK_ASSERT(sc);
911 
912 	advskew = DEMOTE_ADVSKEW(sc);
913 	tv.tv_sec = sc->sc_advbase;
914 	tv.tv_usec = advskew * 1000000 / 256;
915 
916 	ch.carp_version = CARP_VERSION;
917 	ch.carp_type = CARP_ADVERTISEMENT;
918 	ch.carp_vhid = sc->sc_vhid;
919 	ch.carp_advbase = sc->sc_advbase;
920 	ch.carp_advskew = advskew;
921 	ch.carp_authlen = 7;	/* XXX DEFINE */
922 	ch.carp_pad1 = 0;	/* must be zero */
923 	ch.carp_cksum = 0;
924 
925 	/* XXXGL: OpenBSD picks first ifaddr with needed family. */
926 
927 #ifdef INET
928 	if (sc->sc_naddrs) {
929 		struct ip *ip;
930 
931 		m = m_gethdr(M_NOWAIT, MT_DATA);
932 		if (m == NULL) {
933 			CARPSTATS_INC(carps_onomem);
934 			goto resched;
935 		}
936 		len = sizeof(*ip) + sizeof(ch);
937 		m->m_pkthdr.len = len;
938 		m->m_pkthdr.rcvif = NULL;
939 		m->m_len = len;
940 		M_ALIGN(m, m->m_len);
941 		m->m_flags |= M_MCAST;
942 		ip = mtod(m, struct ip *);
943 		ip->ip_v = IPVERSION;
944 		ip->ip_hl = sizeof(*ip) >> 2;
945 		ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
946 		ip->ip_len = htons(len);
947 		ip->ip_off = htons(IP_DF);
948 		ip->ip_ttl = CARP_DFLTTL;
949 		ip->ip_p = IPPROTO_CARP;
950 		ip->ip_sum = 0;
951 		ip_fillid(ip);
952 
953 		ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
954 		if (ifa != NULL) {
955 			ip->ip_src.s_addr =
956 			    ifatoia(ifa)->ia_addr.sin_addr.s_addr;
957 			ifa_free(ifa);
958 		} else
959 			ip->ip_src.s_addr = 0;
960 		ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
961 
962 		ch_ptr = (struct carp_header *)(&ip[1]);
963 		bcopy(&ch, ch_ptr, sizeof(ch));
964 		if (carp_prepare_ad(m, sc, ch_ptr))
965 			goto resched;
966 
967 		m->m_data += sizeof(*ip);
968 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
969 		m->m_data -= sizeof(*ip);
970 
971 		CARPSTATS_INC(carps_opackets);
972 
973 		carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
974 		    &sc->sc_carpdev->if_carp->cif_imo, NULL));
975 	}
976 #endif /* INET */
977 #ifdef INET6
978 	if (sc->sc_naddrs6) {
979 		struct ip6_hdr *ip6;
980 
981 		m = m_gethdr(M_NOWAIT, MT_DATA);
982 		if (m == NULL) {
983 			CARPSTATS_INC(carps_onomem);
984 			goto resched;
985 		}
986 		len = sizeof(*ip6) + sizeof(ch);
987 		m->m_pkthdr.len = len;
988 		m->m_pkthdr.rcvif = NULL;
989 		m->m_len = len;
990 		M_ALIGN(m, m->m_len);
991 		m->m_flags |= M_MCAST;
992 		ip6 = mtod(m, struct ip6_hdr *);
993 		bzero(ip6, sizeof(*ip6));
994 		ip6->ip6_vfc |= IPV6_VERSION;
995 		/* Traffic class isn't defined in ip6 struct instead
996 		 * it gets offset into flowid field */
997 		ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
998 		    IPTOS_DSCP_OFFSET));
999 		ip6->ip6_hlim = CARP_DFLTTL;
1000 		ip6->ip6_nxt = IPPROTO_CARP;
1001 
1002 		/* set the source address */
1003 		ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1004 		if (ifa != NULL) {
1005 			bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1006 			    sizeof(struct in6_addr));
1007 			ifa_free(ifa);
1008 		} else
1009 			/* This should never happen with IPv6. */
1010 			bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1011 
1012 		/* Set the multicast destination. */
1013 		ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1014 		ip6->ip6_dst.s6_addr8[15] = 0x12;
1015 		if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1016 			m_freem(m);
1017 			CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1018 			goto resched;
1019 		}
1020 
1021 		ch_ptr = (struct carp_header *)(&ip6[1]);
1022 		bcopy(&ch, ch_ptr, sizeof(ch));
1023 		if (carp_prepare_ad(m, sc, ch_ptr))
1024 			goto resched;
1025 
1026 		m->m_data += sizeof(*ip6);
1027 		ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1028 		m->m_data -= sizeof(*ip6);
1029 
1030 		CARPSTATS_INC(carps_opackets6);
1031 
1032 		carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1033 		    &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1034 	}
1035 #endif /* INET6 */
1036 
1037 resched:
1038 	callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1039 }
1040 
1041 static void
1042 carp_addroute(struct carp_softc *sc)
1043 {
1044 	struct ifaddr *ifa;
1045 
1046 	CARP_FOREACH_IFA(sc, ifa)
1047 		carp_ifa_addroute(ifa);
1048 }
1049 
1050 static void
1051 carp_ifa_addroute(struct ifaddr *ifa)
1052 {
1053 
1054 	switch (ifa->ifa_addr->sa_family) {
1055 #ifdef INET
1056 	case AF_INET:
1057 		in_addprefix(ifatoia(ifa), RTF_UP);
1058 		ifa_add_loopback_route(ifa,
1059 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1060 		break;
1061 #endif
1062 #ifdef INET6
1063 	case AF_INET6:
1064 		ifa_add_loopback_route(ifa,
1065 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1066 		nd6_add_ifa_lle(ifatoia6(ifa));
1067 		break;
1068 #endif
1069 	}
1070 }
1071 
1072 static void
1073 carp_delroute(struct carp_softc *sc)
1074 {
1075 	struct ifaddr *ifa;
1076 
1077 	CARP_FOREACH_IFA(sc, ifa)
1078 		carp_ifa_delroute(ifa);
1079 }
1080 
1081 static void
1082 carp_ifa_delroute(struct ifaddr *ifa)
1083 {
1084 
1085 	switch (ifa->ifa_addr->sa_family) {
1086 #ifdef INET
1087 	case AF_INET:
1088 		ifa_del_loopback_route(ifa,
1089 		    (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1090 		in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1091 		break;
1092 #endif
1093 #ifdef INET6
1094 	case AF_INET6:
1095 		ifa_del_loopback_route(ifa,
1096 		    (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1097 		nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1098 		break;
1099 #endif
1100 	}
1101 }
1102 
1103 int
1104 carp_master(struct ifaddr *ifa)
1105 {
1106 	struct carp_softc *sc = ifa->ifa_carp;
1107 
1108 	return (sc->sc_state == MASTER);
1109 }
1110 
1111 #ifdef INET
1112 /*
1113  * Broadcast a gratuitous ARP request containing
1114  * the virtual router MAC address for each IP address
1115  * associated with the virtual router.
1116  */
1117 static void
1118 carp_send_arp(struct carp_softc *sc)
1119 {
1120 	struct ifaddr *ifa;
1121 	struct in_addr addr;
1122 
1123 	CARP_FOREACH_IFA(sc, ifa) {
1124 		if (ifa->ifa_addr->sa_family != AF_INET)
1125 			continue;
1126 		addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1127 		arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1128 	}
1129 }
1130 
1131 int
1132 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1133 {
1134 	struct carp_softc *sc = ifa->ifa_carp;
1135 
1136 	if (sc->sc_state == MASTER) {
1137 		*enaddr = LLADDR(&sc->sc_addr);
1138 		return (1);
1139 	}
1140 
1141 	return (0);
1142 }
1143 #endif
1144 
1145 #ifdef INET6
1146 static void
1147 carp_send_na(struct carp_softc *sc)
1148 {
1149 	static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1150 	struct ifaddr *ifa;
1151 	struct in6_addr *in6;
1152 
1153 	CARP_FOREACH_IFA(sc, ifa) {
1154 		if (ifa->ifa_addr->sa_family != AF_INET6)
1155 			continue;
1156 
1157 		in6 = IFA_IN6(ifa);
1158 		nd6_na_output(sc->sc_carpdev, &mcast, in6,
1159 		    ND_NA_FLAG_OVERRIDE, 1, NULL);
1160 		DELAY(1000);	/* XXX */
1161 	}
1162 }
1163 
1164 /*
1165  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1166  * matches and is not a carp address.  Returns NULL otherwise.
1167  */
1168 struct ifaddr *
1169 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1170 {
1171 	struct ifaddr *ifa;
1172 
1173 	NET_EPOCH_ASSERT();
1174 
1175 	ifa = NULL;
1176 	CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1177 		if (ifa->ifa_addr->sa_family != AF_INET6)
1178 			continue;
1179 		if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1180 			continue;
1181 		if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1182 			ifa = NULL;
1183 		else
1184 			ifa_ref(ifa);
1185 		break;
1186 	}
1187 
1188 	return (ifa);
1189 }
1190 
1191 caddr_t
1192 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1193 {
1194 	struct ifaddr *ifa;
1195 
1196 	NET_EPOCH_ASSERT();
1197 
1198 	IFNET_FOREACH_IFA(ifp, ifa)
1199 		if (ifa->ifa_addr->sa_family == AF_INET6 &&
1200 		    IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1201 			struct carp_softc *sc = ifa->ifa_carp;
1202 			struct m_tag *mtag;
1203 
1204 			mtag = m_tag_get(PACKET_TAG_CARP,
1205 			    sizeof(struct carp_softc *), M_NOWAIT);
1206 			if (mtag == NULL)
1207 				/* Better a bit than nothing. */
1208 				return (LLADDR(&sc->sc_addr));
1209 
1210 			bcopy(&sc, mtag + 1, sizeof(sc));
1211 			m_tag_prepend(m, mtag);
1212 
1213 			return (LLADDR(&sc->sc_addr));
1214 		}
1215 
1216 	return (NULL);
1217 }
1218 #endif /* INET6 */
1219 
1220 int
1221 carp_forus(struct ifnet *ifp, u_char *dhost)
1222 {
1223 	struct carp_softc *sc;
1224 	uint8_t *ena = dhost;
1225 
1226 	if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1227 		return (0);
1228 
1229 	CIF_LOCK(ifp->if_carp);
1230 	IFNET_FOREACH_CARP(ifp, sc) {
1231 		CARP_LOCK(sc);
1232 		if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1233 		    ETHER_ADDR_LEN)) {
1234 			CARP_UNLOCK(sc);
1235 			CIF_UNLOCK(ifp->if_carp);
1236 			return (1);
1237 		}
1238 		CARP_UNLOCK(sc);
1239 	}
1240 	CIF_UNLOCK(ifp->if_carp);
1241 
1242 	return (0);
1243 }
1244 
1245 /* Master down timeout event, executed in callout context. */
1246 static void
1247 carp_master_down(void *v)
1248 {
1249 	struct carp_softc *sc = v;
1250 
1251 	CARP_LOCK_ASSERT(sc);
1252 
1253 	CURVNET_SET(sc->sc_carpdev->if_vnet);
1254 	if (sc->sc_state == BACKUP) {
1255 		carp_master_down_locked(sc, "master timed out");
1256 	}
1257 	CURVNET_RESTORE();
1258 
1259 	CARP_UNLOCK(sc);
1260 }
1261 
1262 static void
1263 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1264 {
1265 
1266 	CARP_LOCK_ASSERT(sc);
1267 
1268 	switch (sc->sc_state) {
1269 	case BACKUP:
1270 		carp_set_state(sc, MASTER, reason);
1271 		carp_send_ad_locked(sc);
1272 #ifdef INET
1273 		carp_send_arp(sc);
1274 #endif
1275 #ifdef INET6
1276 		carp_send_na(sc);
1277 #endif
1278 		carp_setrun(sc, 0);
1279 		carp_addroute(sc);
1280 		break;
1281 	case INIT:
1282 	case MASTER:
1283 #ifdef INVARIANTS
1284 		panic("carp: VHID %u@%s: master_down event in %s state\n",
1285 		    sc->sc_vhid,
1286 		    sc->sc_carpdev->if_xname,
1287 		    sc->sc_state ? "MASTER" : "INIT");
1288 #endif
1289 		break;
1290 	}
1291 }
1292 
1293 /*
1294  * When in backup state, af indicates whether to reset the master down timer
1295  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1296  */
1297 static void
1298 carp_setrun(struct carp_softc *sc, sa_family_t af)
1299 {
1300 	struct timeval tv;
1301 
1302 	CARP_LOCK_ASSERT(sc);
1303 
1304 	if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1305 	    sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1306 	    (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1307 	    !V_carp_allow)
1308 		return;
1309 
1310 	switch (sc->sc_state) {
1311 	case INIT:
1312 		carp_set_state(sc, BACKUP, "initialization complete");
1313 		carp_setrun(sc, 0);
1314 		break;
1315 	case BACKUP:
1316 		callout_stop(&sc->sc_ad_tmo);
1317 		tv.tv_sec = 3 * sc->sc_advbase;
1318 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1319 		switch (af) {
1320 #ifdef INET
1321 		case AF_INET:
1322 			callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1323 			    carp_master_down, sc);
1324 			break;
1325 #endif
1326 #ifdef INET6
1327 		case AF_INET6:
1328 			callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1329 			    carp_master_down, sc);
1330 			break;
1331 #endif
1332 		default:
1333 #ifdef INET
1334 			if (sc->sc_naddrs)
1335 				callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1336 				    carp_master_down, sc);
1337 #endif
1338 #ifdef INET6
1339 			if (sc->sc_naddrs6)
1340 				callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1341 				    carp_master_down, sc);
1342 #endif
1343 			break;
1344 		}
1345 		break;
1346 	case MASTER:
1347 		tv.tv_sec = sc->sc_advbase;
1348 		tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1349 		callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1350 		    carp_send_ad, sc);
1351 		break;
1352 	}
1353 }
1354 
1355 /*
1356  * Setup multicast structures.
1357  */
1358 static int
1359 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1360 {
1361 	struct ifnet *ifp = cif->cif_ifp;
1362 	int error = 0;
1363 
1364 	switch (sa) {
1365 #ifdef INET
1366 	case AF_INET:
1367 	    {
1368 		struct ip_moptions *imo = &cif->cif_imo;
1369 		struct in_mfilter *imf;
1370 		struct in_addr addr;
1371 
1372 		if (ip_mfilter_first(&imo->imo_head) != NULL)
1373 			return (0);
1374 
1375 		imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1376 		ip_mfilter_init(&imo->imo_head);
1377 		imo->imo_multicast_vif = -1;
1378 
1379 		addr.s_addr = htonl(INADDR_CARP_GROUP);
1380 		if ((error = in_joingroup(ifp, &addr, NULL,
1381 		    &imf->imf_inm)) != 0) {
1382 			ip_mfilter_free(imf);
1383 			break;
1384 		}
1385 
1386 		ip_mfilter_insert(&imo->imo_head, imf);
1387 		imo->imo_multicast_ifp = ifp;
1388 		imo->imo_multicast_ttl = CARP_DFLTTL;
1389 		imo->imo_multicast_loop = 0;
1390 		break;
1391 	   }
1392 #endif
1393 #ifdef INET6
1394 	case AF_INET6:
1395 	    {
1396 		struct ip6_moptions *im6o = &cif->cif_im6o;
1397 		struct in6_mfilter *im6f[2];
1398 		struct in6_addr in6;
1399 
1400 		if (ip6_mfilter_first(&im6o->im6o_head))
1401 			return (0);
1402 
1403 		im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1404 		im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1405 
1406 		ip6_mfilter_init(&im6o->im6o_head);
1407 		im6o->im6o_multicast_hlim = CARP_DFLTTL;
1408 		im6o->im6o_multicast_ifp = ifp;
1409 
1410 		/* Join IPv6 CARP multicast group. */
1411 		bzero(&in6, sizeof(in6));
1412 		in6.s6_addr16[0] = htons(0xff02);
1413 		in6.s6_addr8[15] = 0x12;
1414 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1415 			ip6_mfilter_free(im6f[0]);
1416 			ip6_mfilter_free(im6f[1]);
1417 			break;
1418 		}
1419 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1420 			ip6_mfilter_free(im6f[0]);
1421 			ip6_mfilter_free(im6f[1]);
1422 			break;
1423 		}
1424 
1425 		/* Join solicited multicast address. */
1426 		bzero(&in6, sizeof(in6));
1427 		in6.s6_addr16[0] = htons(0xff02);
1428 		in6.s6_addr32[1] = 0;
1429 		in6.s6_addr32[2] = htonl(1);
1430 		in6.s6_addr32[3] = 0;
1431 		in6.s6_addr8[12] = 0xff;
1432 
1433 		if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1434 			ip6_mfilter_free(im6f[0]);
1435 			ip6_mfilter_free(im6f[1]);
1436 			break;
1437 		}
1438 
1439 		if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1440 			in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1441 			ip6_mfilter_free(im6f[0]);
1442 			ip6_mfilter_free(im6f[1]);
1443 			break;
1444 		}
1445 		ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1446 		ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1447 		break;
1448 	    }
1449 #endif
1450 	}
1451 
1452 	return (error);
1453 }
1454 
1455 /*
1456  * Free multicast structures.
1457  */
1458 static void
1459 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1460 {
1461 #ifdef INET
1462 	struct ip_moptions *imo = &cif->cif_imo;
1463 	struct in_mfilter *imf;
1464 #endif
1465 #ifdef INET6
1466 	struct ip6_moptions *im6o = &cif->cif_im6o;
1467 	struct in6_mfilter *im6f;
1468 #endif
1469 	sx_assert(&carp_sx, SA_XLOCKED);
1470 
1471 	switch (sa) {
1472 #ifdef INET
1473 	case AF_INET:
1474 		if (cif->cif_naddrs != 0)
1475 			break;
1476 
1477 		while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1478 			ip_mfilter_remove(&imo->imo_head, imf);
1479 			in_leavegroup(imf->imf_inm, NULL);
1480 			ip_mfilter_free(imf);
1481 		}
1482 		break;
1483 #endif
1484 #ifdef INET6
1485 	case AF_INET6:
1486 		if (cif->cif_naddrs6 != 0)
1487 			break;
1488 
1489 		while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1490 			ip6_mfilter_remove(&im6o->im6o_head, im6f);
1491 			in6_leavegroup(im6f->im6f_in6m, NULL);
1492 			ip6_mfilter_free(im6f);
1493 		}
1494 		break;
1495 #endif
1496 	}
1497 }
1498 
1499 int
1500 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1501 {
1502 	struct m_tag *mtag;
1503 	struct carp_softc *sc;
1504 
1505 	if (!sa)
1506 		return (0);
1507 
1508 	switch (sa->sa_family) {
1509 #ifdef INET
1510 	case AF_INET:
1511 		break;
1512 #endif
1513 #ifdef INET6
1514 	case AF_INET6:
1515 		break;
1516 #endif
1517 	default:
1518 		return (0);
1519 	}
1520 
1521 	mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1522 	if (mtag == NULL)
1523 		return (0);
1524 
1525 	bcopy(mtag + 1, &sc, sizeof(sc));
1526 
1527 	/* Set the source MAC address to the Virtual Router MAC Address. */
1528 	switch (ifp->if_type) {
1529 	case IFT_ETHER:
1530 	case IFT_BRIDGE:
1531 	case IFT_L2VLAN: {
1532 			struct ether_header *eh;
1533 
1534 			eh = mtod(m, struct ether_header *);
1535 			eh->ether_shost[0] = 0;
1536 			eh->ether_shost[1] = 0;
1537 			eh->ether_shost[2] = 0x5e;
1538 			eh->ether_shost[3] = 0;
1539 			eh->ether_shost[4] = 1;
1540 			eh->ether_shost[5] = sc->sc_vhid;
1541 		}
1542 		break;
1543 	default:
1544 		printf("%s: carp is not supported for the %d interface type\n",
1545 		    ifp->if_xname, ifp->if_type);
1546 		return (EOPNOTSUPP);
1547 	}
1548 
1549 	return (0);
1550 }
1551 
1552 static struct carp_softc*
1553 carp_alloc(struct ifnet *ifp)
1554 {
1555 	struct carp_softc *sc;
1556 	struct carp_if *cif;
1557 
1558 	sx_assert(&carp_sx, SA_XLOCKED);
1559 
1560 	if ((cif = ifp->if_carp) == NULL)
1561 		cif = carp_alloc_if(ifp);
1562 
1563 	sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1564 
1565 	sc->sc_advbase = CARP_DFLTINTV;
1566 	sc->sc_vhid = -1;	/* required setting */
1567 	sc->sc_init_counter = 1;
1568 	sc->sc_state = INIT;
1569 
1570 	sc->sc_ifasiz = sizeof(struct ifaddr *);
1571 	sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1572 	sc->sc_carpdev = ifp;
1573 
1574 	CARP_LOCK_INIT(sc);
1575 #ifdef INET
1576 	callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1577 #endif
1578 #ifdef INET6
1579 	callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1580 #endif
1581 	callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1582 
1583 	CIF_LOCK(cif);
1584 	TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1585 	CIF_UNLOCK(cif);
1586 
1587 	mtx_lock(&carp_mtx);
1588 	LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1589 	mtx_unlock(&carp_mtx);
1590 
1591 	return (sc);
1592 }
1593 
1594 static void
1595 carp_grow_ifas(struct carp_softc *sc)
1596 {
1597 	struct ifaddr **new;
1598 
1599 	new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1600 	CARP_LOCK(sc);
1601 	bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1602 	free(sc->sc_ifas, M_CARP);
1603 	sc->sc_ifas = new;
1604 	sc->sc_ifasiz *= 2;
1605 	CARP_UNLOCK(sc);
1606 }
1607 
1608 static void
1609 carp_destroy(struct carp_softc *sc)
1610 {
1611 	struct ifnet *ifp = sc->sc_carpdev;
1612 	struct carp_if *cif = ifp->if_carp;
1613 
1614 	sx_assert(&carp_sx, SA_XLOCKED);
1615 
1616 	if (sc->sc_suppress)
1617 		carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1618 	CARP_UNLOCK(sc);
1619 
1620 	CIF_LOCK(cif);
1621 	TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1622 	CIF_UNLOCK(cif);
1623 
1624 	mtx_lock(&carp_mtx);
1625 	LIST_REMOVE(sc, sc_next);
1626 	mtx_unlock(&carp_mtx);
1627 
1628 	callout_drain(&sc->sc_ad_tmo);
1629 #ifdef INET
1630 	callout_drain(&sc->sc_md_tmo);
1631 #endif
1632 #ifdef INET6
1633 	callout_drain(&sc->sc_md6_tmo);
1634 #endif
1635 	CARP_LOCK_DESTROY(sc);
1636 
1637 	free(sc->sc_ifas, M_CARP);
1638 	free(sc, M_CARP);
1639 }
1640 
1641 static struct carp_if*
1642 carp_alloc_if(struct ifnet *ifp)
1643 {
1644 	struct carp_if *cif;
1645 	int error;
1646 
1647 	cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1648 
1649 	if ((error = ifpromisc(ifp, 1)) != 0)
1650 		printf("%s: ifpromisc(%s) failed: %d\n",
1651 		    __func__, ifp->if_xname, error);
1652 	else
1653 		cif->cif_flags |= CIF_PROMISC;
1654 
1655 	CIF_LOCK_INIT(cif);
1656 	cif->cif_ifp = ifp;
1657 	TAILQ_INIT(&cif->cif_vrs);
1658 
1659 	IF_ADDR_WLOCK(ifp);
1660 	ifp->if_carp = cif;
1661 	if_ref(ifp);
1662 	IF_ADDR_WUNLOCK(ifp);
1663 
1664 	return (cif);
1665 }
1666 
1667 static void
1668 carp_free_if(struct carp_if *cif)
1669 {
1670 	struct ifnet *ifp = cif->cif_ifp;
1671 
1672 	CIF_LOCK_ASSERT(cif);
1673 	KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1674 	    __func__));
1675 
1676 	IF_ADDR_WLOCK(ifp);
1677 	ifp->if_carp = NULL;
1678 	IF_ADDR_WUNLOCK(ifp);
1679 
1680 	CIF_LOCK_DESTROY(cif);
1681 
1682 	if (cif->cif_flags & CIF_PROMISC)
1683 		ifpromisc(ifp, 0);
1684 	if_rele(ifp);
1685 
1686 	free(cif, M_CARP);
1687 }
1688 
1689 static void
1690 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1691 {
1692 
1693 	CARP_LOCK(sc);
1694 	carpr->carpr_state = sc->sc_state;
1695 	carpr->carpr_vhid = sc->sc_vhid;
1696 	carpr->carpr_advbase = sc->sc_advbase;
1697 	carpr->carpr_advskew = sc->sc_advskew;
1698 	if (priv)
1699 		bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1700 	else
1701 		bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1702 	CARP_UNLOCK(sc);
1703 }
1704 
1705 int
1706 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1707 {
1708 	struct carpreq carpr;
1709 	struct ifnet *ifp;
1710 	struct carp_softc *sc = NULL;
1711 	int error = 0, locked = 0;
1712 
1713 	if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1714 		return (error);
1715 
1716 	ifp = ifunit_ref(ifr->ifr_name);
1717 	if (ifp == NULL)
1718 		return (ENXIO);
1719 
1720 	switch (ifp->if_type) {
1721 	case IFT_ETHER:
1722 	case IFT_L2VLAN:
1723 	case IFT_BRIDGE:
1724 		break;
1725 	default:
1726 		error = EOPNOTSUPP;
1727 		goto out;
1728 	}
1729 
1730 	if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1731 		error = EADDRNOTAVAIL;
1732 		goto out;
1733 	}
1734 
1735 	sx_xlock(&carp_sx);
1736 	switch (cmd) {
1737 	case SIOCSVH:
1738 		if ((error = priv_check(td, PRIV_NETINET_CARP)))
1739 			break;
1740 		if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1741 		    carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1742 			error = EINVAL;
1743 			break;
1744 		}
1745 
1746 		if (ifp->if_carp) {
1747 			IFNET_FOREACH_CARP(ifp, sc)
1748 				if (sc->sc_vhid == carpr.carpr_vhid)
1749 					break;
1750 		}
1751 		if (sc == NULL) {
1752 			sc = carp_alloc(ifp);
1753 			CARP_LOCK(sc);
1754 			sc->sc_vhid = carpr.carpr_vhid;
1755 			LLADDR(&sc->sc_addr)[0] = 0;
1756 			LLADDR(&sc->sc_addr)[1] = 0;
1757 			LLADDR(&sc->sc_addr)[2] = 0x5e;
1758 			LLADDR(&sc->sc_addr)[3] = 0;
1759 			LLADDR(&sc->sc_addr)[4] = 1;
1760 			LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1761 		} else
1762 			CARP_LOCK(sc);
1763 		locked = 1;
1764 		if (carpr.carpr_advbase > 0) {
1765 			if (carpr.carpr_advbase > 255 ||
1766 			    carpr.carpr_advbase < CARP_DFLTINTV) {
1767 				error = EINVAL;
1768 				break;
1769 			}
1770 			sc->sc_advbase = carpr.carpr_advbase;
1771 		}
1772 		if (carpr.carpr_advskew >= 255) {
1773 			error = EINVAL;
1774 			break;
1775 		}
1776 		sc->sc_advskew = carpr.carpr_advskew;
1777 		if (carpr.carpr_key[0] != '\0') {
1778 			bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1779 			carp_hmac_prepare(sc);
1780 		}
1781 		if (sc->sc_state != INIT &&
1782 		    carpr.carpr_state != sc->sc_state) {
1783 			switch (carpr.carpr_state) {
1784 			case BACKUP:
1785 				callout_stop(&sc->sc_ad_tmo);
1786 				carp_set_state(sc, BACKUP,
1787 				    "user requested via ifconfig");
1788 				carp_setrun(sc, 0);
1789 				carp_delroute(sc);
1790 				break;
1791 			case MASTER:
1792 				carp_master_down_locked(sc,
1793 				    "user requested via ifconfig");
1794 				break;
1795 			default:
1796 				break;
1797 			}
1798 		}
1799 		break;
1800 
1801 	case SIOCGVH:
1802 	    {
1803 		int priveleged;
1804 
1805 		if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1806 			error = EINVAL;
1807 			break;
1808 		}
1809 		if (carpr.carpr_count < 1) {
1810 			error = EMSGSIZE;
1811 			break;
1812 		}
1813 		if (ifp->if_carp == NULL) {
1814 			error = ENOENT;
1815 			break;
1816 		}
1817 
1818 		priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1819 		if (carpr.carpr_vhid != 0) {
1820 			IFNET_FOREACH_CARP(ifp, sc)
1821 				if (sc->sc_vhid == carpr.carpr_vhid)
1822 					break;
1823 			if (sc == NULL) {
1824 				error = ENOENT;
1825 				break;
1826 			}
1827 			carp_carprcp(&carpr, sc, priveleged);
1828 			error = copyout(&carpr, ifr_data_get_ptr(ifr),
1829 			    sizeof(carpr));
1830 		} else  {
1831 			int i, count;
1832 
1833 			count = 0;
1834 			IFNET_FOREACH_CARP(ifp, sc)
1835 				count++;
1836 
1837 			if (count > carpr.carpr_count) {
1838 				CIF_UNLOCK(ifp->if_carp);
1839 				error = EMSGSIZE;
1840 				break;
1841 			}
1842 
1843 			i = 0;
1844 			IFNET_FOREACH_CARP(ifp, sc) {
1845 				carp_carprcp(&carpr, sc, priveleged);
1846 				carpr.carpr_count = count;
1847 				error = copyout(&carpr,
1848 				    (caddr_t)ifr_data_get_ptr(ifr) +
1849 				    (i * sizeof(carpr)), sizeof(carpr));
1850 				if (error) {
1851 					CIF_UNLOCK(ifp->if_carp);
1852 					break;
1853 				}
1854 				i++;
1855 			}
1856 		}
1857 		break;
1858 	    }
1859 	default:
1860 		error = EINVAL;
1861 	}
1862 	sx_xunlock(&carp_sx);
1863 
1864 out:
1865 	if (locked)
1866 		CARP_UNLOCK(sc);
1867 	if_rele(ifp);
1868 
1869 	return (error);
1870 }
1871 
1872 static int
1873 carp_get_vhid(struct ifaddr *ifa)
1874 {
1875 
1876 	if (ifa == NULL || ifa->ifa_carp == NULL)
1877 		return (0);
1878 
1879 	return (ifa->ifa_carp->sc_vhid);
1880 }
1881 
1882 int
1883 carp_attach(struct ifaddr *ifa, int vhid)
1884 {
1885 	struct ifnet *ifp = ifa->ifa_ifp;
1886 	struct carp_if *cif = ifp->if_carp;
1887 	struct carp_softc *sc;
1888 	int index, error;
1889 
1890 	KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1891 
1892 	switch (ifa->ifa_addr->sa_family) {
1893 #ifdef INET
1894 	case AF_INET:
1895 #endif
1896 #ifdef INET6
1897 	case AF_INET6:
1898 #endif
1899 		break;
1900 	default:
1901 		return (EPROTOTYPE);
1902 	}
1903 
1904 	sx_xlock(&carp_sx);
1905 	if (ifp->if_carp == NULL) {
1906 		sx_xunlock(&carp_sx);
1907 		return (ENOPROTOOPT);
1908 	}
1909 
1910 	IFNET_FOREACH_CARP(ifp, sc)
1911 		if (sc->sc_vhid == vhid)
1912 			break;
1913 	if (sc == NULL) {
1914 		sx_xunlock(&carp_sx);
1915 		return (ENOENT);
1916 	}
1917 
1918 	error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1919 	if (error) {
1920 		CIF_FREE(cif);
1921 		sx_xunlock(&carp_sx);
1922 		return (error);
1923 	}
1924 
1925 	index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1926 	if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1927 		carp_grow_ifas(sc);
1928 
1929 	switch (ifa->ifa_addr->sa_family) {
1930 #ifdef INET
1931 	case AF_INET:
1932 		cif->cif_naddrs++;
1933 		sc->sc_naddrs++;
1934 		break;
1935 #endif
1936 #ifdef INET6
1937 	case AF_INET6:
1938 		cif->cif_naddrs6++;
1939 		sc->sc_naddrs6++;
1940 		break;
1941 #endif
1942 	}
1943 
1944 	ifa_ref(ifa);
1945 
1946 	CARP_LOCK(sc);
1947 	sc->sc_ifas[index - 1] = ifa;
1948 	ifa->ifa_carp = sc;
1949 	carp_hmac_prepare(sc);
1950 	carp_sc_state(sc);
1951 	CARP_UNLOCK(sc);
1952 
1953 	sx_xunlock(&carp_sx);
1954 
1955 	return (0);
1956 }
1957 
1958 void
1959 carp_detach(struct ifaddr *ifa, bool keep_cif)
1960 {
1961 	struct ifnet *ifp = ifa->ifa_ifp;
1962 	struct carp_if *cif = ifp->if_carp;
1963 	struct carp_softc *sc = ifa->ifa_carp;
1964 	int i, index;
1965 
1966 	KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1967 
1968 	sx_xlock(&carp_sx);
1969 
1970 	CARP_LOCK(sc);
1971 	/* Shift array. */
1972 	index = sc->sc_naddrs + sc->sc_naddrs6;
1973 	for (i = 0; i < index; i++)
1974 		if (sc->sc_ifas[i] == ifa)
1975 			break;
1976 	KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1977 	for (; i < index - 1; i++)
1978 		sc->sc_ifas[i] = sc->sc_ifas[i+1];
1979 	sc->sc_ifas[index - 1] = NULL;
1980 
1981 	switch (ifa->ifa_addr->sa_family) {
1982 #ifdef INET
1983 	case AF_INET:
1984 		cif->cif_naddrs--;
1985 		sc->sc_naddrs--;
1986 		break;
1987 #endif
1988 #ifdef INET6
1989 	case AF_INET6:
1990 		cif->cif_naddrs6--;
1991 		sc->sc_naddrs6--;
1992 		break;
1993 #endif
1994 	}
1995 
1996 	carp_ifa_delroute(ifa);
1997 	carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
1998 
1999 	ifa->ifa_carp = NULL;
2000 	ifa_free(ifa);
2001 
2002 	carp_hmac_prepare(sc);
2003 	carp_sc_state(sc);
2004 
2005 	if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2006 		carp_destroy(sc);
2007 	else
2008 		CARP_UNLOCK(sc);
2009 
2010 	if (!keep_cif)
2011 		CIF_FREE(cif);
2012 
2013 	sx_xunlock(&carp_sx);
2014 }
2015 
2016 static void
2017 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2018 {
2019 
2020 	CARP_LOCK_ASSERT(sc);
2021 
2022 	if (sc->sc_state != state) {
2023 		const char *carp_states[] = { CARP_STATES };
2024 		char subsys[IFNAMSIZ+5];
2025 
2026 		snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2027 		    sc->sc_carpdev->if_xname);
2028 
2029 		CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2030 		    carp_states[sc->sc_state], carp_states[state], reason);
2031 
2032 		sc->sc_state = state;
2033 
2034 		devctl_notify("CARP", subsys, carp_states[state], NULL);
2035 	}
2036 }
2037 
2038 static void
2039 carp_linkstate(struct ifnet *ifp)
2040 {
2041 	struct carp_softc *sc;
2042 
2043 	CIF_LOCK(ifp->if_carp);
2044 	IFNET_FOREACH_CARP(ifp, sc) {
2045 		CARP_LOCK(sc);
2046 		carp_sc_state(sc);
2047 		CARP_UNLOCK(sc);
2048 	}
2049 	CIF_UNLOCK(ifp->if_carp);
2050 }
2051 
2052 static void
2053 carp_sc_state(struct carp_softc *sc)
2054 {
2055 
2056 	CARP_LOCK_ASSERT(sc);
2057 
2058 	if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2059 	    !(sc->sc_carpdev->if_flags & IFF_UP) ||
2060 	    !V_carp_allow) {
2061 		callout_stop(&sc->sc_ad_tmo);
2062 #ifdef INET
2063 		callout_stop(&sc->sc_md_tmo);
2064 #endif
2065 #ifdef INET6
2066 		callout_stop(&sc->sc_md6_tmo);
2067 #endif
2068 		carp_set_state(sc, INIT, "hardware interface down");
2069 		carp_setrun(sc, 0);
2070 		if (!sc->sc_suppress)
2071 			carp_demote_adj(V_carp_ifdown_adj, "interface down");
2072 		sc->sc_suppress = 1;
2073 	} else {
2074 		carp_set_state(sc, INIT, "hardware interface up");
2075 		carp_setrun(sc, 0);
2076 		if (sc->sc_suppress)
2077 			carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2078 		sc->sc_suppress = 0;
2079 	}
2080 }
2081 
2082 static void
2083 carp_demote_adj(int adj, char *reason)
2084 {
2085 	atomic_add_int(&V_carp_demotion, adj);
2086 	CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2087 	taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2088 }
2089 
2090 static int
2091 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2092 {
2093 	int new, error;
2094 	struct carp_softc *sc;
2095 
2096 	new = V_carp_allow;
2097 	error = sysctl_handle_int(oidp, &new, 0, req);
2098 	if (error || !req->newptr)
2099 		return (error);
2100 
2101 	if (V_carp_allow != new) {
2102 		V_carp_allow = new;
2103 
2104 		mtx_lock(&carp_mtx);
2105 		LIST_FOREACH(sc, &carp_list, sc_next) {
2106 			CARP_LOCK(sc);
2107 			if (curvnet == sc->sc_carpdev->if_vnet)
2108 				carp_sc_state(sc);
2109 			CARP_UNLOCK(sc);
2110 		}
2111 		mtx_unlock(&carp_mtx);
2112 	}
2113 
2114 	return (0);
2115 }
2116 
2117 static int
2118 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2119 {
2120 	int new, error;
2121 
2122 	new = V_carp_dscp;
2123 	error = sysctl_handle_int(oidp, &new, 0, req);
2124 	if (error || !req->newptr)
2125 		return (error);
2126 
2127 	if (new < 0 || new > 63)
2128 		return (EINVAL);
2129 
2130 	V_carp_dscp = new;
2131 
2132 	return (0);
2133 }
2134 
2135 static int
2136 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2137 {
2138 	int new, error;
2139 
2140 	new = V_carp_demotion;
2141 	error = sysctl_handle_int(oidp, &new, 0, req);
2142 	if (error || !req->newptr)
2143 		return (error);
2144 
2145 	carp_demote_adj(new, "sysctl");
2146 
2147 	return (0);
2148 }
2149 
2150 #ifdef INET
2151 extern  struct domain inetdomain;
2152 static struct protosw in_carp_protosw = {
2153 	.pr_type =		SOCK_RAW,
2154 	.pr_domain =		&inetdomain,
2155 	.pr_protocol =		IPPROTO_CARP,
2156 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2157 	.pr_input =		carp_input,
2158 	.pr_output =		rip_output,
2159 	.pr_ctloutput =		rip_ctloutput,
2160 	.pr_usrreqs =		&rip_usrreqs
2161 };
2162 #endif
2163 
2164 #ifdef INET6
2165 extern	struct domain inet6domain;
2166 static struct protosw in6_carp_protosw = {
2167 	.pr_type =		SOCK_RAW,
2168 	.pr_domain =		&inet6domain,
2169 	.pr_protocol =		IPPROTO_CARP,
2170 	.pr_flags =		PR_ATOMIC|PR_ADDR,
2171 	.pr_input =		carp6_input,
2172 	.pr_output =		rip6_output,
2173 	.pr_ctloutput =		rip6_ctloutput,
2174 	.pr_usrreqs =		&rip6_usrreqs
2175 };
2176 #endif
2177 
2178 static void
2179 carp_mod_cleanup(void)
2180 {
2181 
2182 #ifdef INET
2183 	if (proto_reg[CARP_INET] == 0) {
2184 		(void)ipproto_unregister(IPPROTO_CARP);
2185 		pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2186 		proto_reg[CARP_INET] = -1;
2187 	}
2188 	carp_iamatch_p = NULL;
2189 #endif
2190 #ifdef INET6
2191 	if (proto_reg[CARP_INET6] == 0) {
2192 		(void)ip6proto_unregister(IPPROTO_CARP);
2193 		pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2194 		proto_reg[CARP_INET6] = -1;
2195 	}
2196 	carp_iamatch6_p = NULL;
2197 	carp_macmatch6_p = NULL;
2198 #endif
2199 	carp_ioctl_p = NULL;
2200 	carp_attach_p = NULL;
2201 	carp_detach_p = NULL;
2202 	carp_get_vhid_p = NULL;
2203 	carp_linkstate_p = NULL;
2204 	carp_forus_p = NULL;
2205 	carp_output_p = NULL;
2206 	carp_demote_adj_p = NULL;
2207 	carp_master_p = NULL;
2208 	mtx_unlock(&carp_mtx);
2209 	taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2210 	mtx_destroy(&carp_mtx);
2211 	sx_destroy(&carp_sx);
2212 }
2213 
2214 static int
2215 carp_mod_load(void)
2216 {
2217 	int err;
2218 
2219 	mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2220 	sx_init(&carp_sx, "carp_sx");
2221 	LIST_INIT(&carp_list);
2222 	carp_get_vhid_p = carp_get_vhid;
2223 	carp_forus_p = carp_forus;
2224 	carp_output_p = carp_output;
2225 	carp_linkstate_p = carp_linkstate;
2226 	carp_ioctl_p = carp_ioctl;
2227 	carp_attach_p = carp_attach;
2228 	carp_detach_p = carp_detach;
2229 	carp_demote_adj_p = carp_demote_adj;
2230 	carp_master_p = carp_master;
2231 #ifdef INET6
2232 	carp_iamatch6_p = carp_iamatch6;
2233 	carp_macmatch6_p = carp_macmatch6;
2234 	proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2235 	    (struct protosw *)&in6_carp_protosw);
2236 	if (proto_reg[CARP_INET6]) {
2237 		printf("carp: error %d attaching to PF_INET6\n",
2238 		    proto_reg[CARP_INET6]);
2239 		carp_mod_cleanup();
2240 		return (proto_reg[CARP_INET6]);
2241 	}
2242 	err = ip6proto_register(IPPROTO_CARP);
2243 	if (err) {
2244 		printf("carp: error %d registering with INET6\n", err);
2245 		carp_mod_cleanup();
2246 		return (err);
2247 	}
2248 #endif
2249 #ifdef INET
2250 	carp_iamatch_p = carp_iamatch;
2251 	proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2252 	if (proto_reg[CARP_INET]) {
2253 		printf("carp: error %d attaching to PF_INET\n",
2254 		    proto_reg[CARP_INET]);
2255 		carp_mod_cleanup();
2256 		return (proto_reg[CARP_INET]);
2257 	}
2258 	err = ipproto_register(IPPROTO_CARP);
2259 	if (err) {
2260 		printf("carp: error %d registering with INET\n", err);
2261 		carp_mod_cleanup();
2262 		return (err);
2263 	}
2264 #endif
2265 	return (0);
2266 }
2267 
2268 static int
2269 carp_modevent(module_t mod, int type, void *data)
2270 {
2271 	switch (type) {
2272 	case MOD_LOAD:
2273 		return carp_mod_load();
2274 		/* NOTREACHED */
2275 	case MOD_UNLOAD:
2276 		mtx_lock(&carp_mtx);
2277 		if (LIST_EMPTY(&carp_list))
2278 			carp_mod_cleanup();
2279 		else {
2280 			mtx_unlock(&carp_mtx);
2281 			return (EBUSY);
2282 		}
2283 		break;
2284 
2285 	default:
2286 		return (EINVAL);
2287 	}
2288 
2289 	return (0);
2290 }
2291 
2292 static moduledata_t carp_mod = {
2293 	"carp",
2294 	carp_modevent,
2295 	0
2296 };
2297 
2298 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);
2299