sys/netinet/ip_carp.c

   1 /*
   2  * Copyright (c) 2002 Michael Shalayeff. All rights reserved.
   3  * Copyright (c) 2003 Ryan McBride. All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
  18  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  19  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  20  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  22  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  23  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  24  * THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26 /*
  27  * $FreeBSD: src/sys/netinet/ip_carp.c,v 1.48 2007/02/02 09:39:09 glebius Exp $
  28  */
  29
  30 #include "opt_carp.h"
  31 #include "opt_inet.h"
  32 #include "opt_inet6.h"
  33
  34 #include <sys/param.h>
  35 #include <sys/systm.h>
  36 #include <sys/kernel.h>
  37 #include <sys/in_cksum.h>
  38 #include <sys/limits.h>
  39 #include <sys/malloc.h>
  40 #include <sys/mbuf.h>
  41 #include <sys/time.h>
  42 #include <sys/proc.h>
  43 #include <sys/priv.h>
  44 #include <sys/sockio.h>
  45 #include <sys/socket.h>
  46 #include <sys/sysctl.h>
  47 #include <sys/syslog.h>
  48
  49 #include <machine/stdarg.h>
  50 #include <crypto/sha1.h>
  51
  52 #include <net/bpf.h>
  53 #include <net/ethernet.h>
  54 #include <net/if.h>
  55 #include <net/if_dl.h>
  56 #include <net/if_types.h>
  57 #include <net/route.h>
  58 #include <net/if_clone.h>
  59
  60 #ifdef INET
  61 #include <netinet/in.h>
  62 #include <netinet/in_var.h>
  63 #include <netinet/in_systm.h>
  64 #include <netinet/ip.h>
  65 #include <netinet/ip_var.h>
  66 #include <netinet/if_ether.h>
  67 #endif
  68
  69 #ifdef INET6
  70 #include <netinet/icmp6.h>
  71 #include <netinet/ip6.h>
  72 #include <netinet6/ip6_var.h>
  73 #include <netinet6/scope6_var.h>
  74 #include <netinet6/nd6.h>
  75 #endif
  76
  77 #include <netinet/ip_carp.h>
  78
  79 #define CARP_IFNAME             "carp"
  80 #define CARP_IS_RUNNING(ifp)    \
  81         (((ifp)->if_flags & (IFF_UP | IFF_RUNNING)) == (IFF_UP | IFF_RUNNING))
  82
  83 struct carp_vhaddr {
  84         uint32_t                vha_flags;      /* CARP_VHAF_ */
  85         const struct in_ifaddr  *vha_ia;        /* carp address */
  86         const struct in_ifaddr  *vha_iaback;    /* backing address */
  87         TAILQ_ENTRY(carp_vhaddr) vha_link;
  88 };
  89 TAILQ_HEAD(carp_vhaddr_list, carp_vhaddr);
  90
  91 struct carp_softc {
  92         struct ifnet             sc_if;
  93         struct ifnet            *sc_carpdev;    /* parent interface */
  94         struct carp_vhaddr_list  sc_vha_list;   /* virtual addr list */
  95
  96         const struct in_ifaddr  *sc_ia;         /* primary iface address v4 */
  97         struct ip_moptions       sc_imo;
  98
  99 #ifdef INET6
 100         struct in6_ifaddr       *sc_ia6;        /* primary iface address v6 */
 101         struct ip6_moptions      sc_im6o;
 102 #endif /* INET6 */
 103         TAILQ_ENTRY(carp_softc)  sc_list;
 104
 105         enum { INIT = 0, BACKUP, MASTER }
 106                                  sc_state;
 107         int                      sc_dead;
 108
 109         int                      sc_suppress;
 110
 111         int                      sc_sendad_errors;
 112 #define CARP_SENDAD_MAX_ERRORS  3
 113         int                      sc_sendad_success;
 114 #define CARP_SENDAD_MIN_SUCCESS 3
 115
 116         int                      sc_vhid;
 117         int                      sc_advskew;
 118         int                      sc_naddrs;     /* actually used IPv4 vha */
 119         int                      sc_naddrs6;
 120         int                      sc_advbase;    /* seconds */
 121         int                      sc_init_counter;
 122         uint64_t                 sc_counter;
 123
 124         /* authentication */
 125 #define CARP_HMAC_PAD   64
 126         unsigned char            sc_key[CARP_KEY_LEN];
 127         unsigned char            sc_pad[CARP_HMAC_PAD];
 128         SHA1_CTX                 sc_sha1;
 129
 130         struct callout           sc_ad_tmo;     /* advertisement timeout */
 131         struct callout           sc_md_tmo;     /* master down timeout */
 132         struct callout           sc_md6_tmo;    /* master down timeout */
 133
 134         LIST_ENTRY(carp_softc)   sc_next;       /* Interface clue */
 135 };
 136
 137 struct carp_if {
 138         TAILQ_HEAD(, carp_softc) vhif_vrs;
 139 };
 140
 141 enum    { CARP_COUNT_MASTER, CARP_COUNT_RUNNING };
 142
 143 SYSCTL_DECL(_net_inet_carp);
 144
 145 static int carp_opts[CARPCTL_MAXID] = { 0, 1, 0, 1, 0, 0 }; /* XXX for now */
 146 SYSCTL_INT(_net_inet_carp, CARPCTL_ALLOW, allow, CTLFLAG_RW,
 147     &carp_opts[CARPCTL_ALLOW], 0, "Accept incoming CARP packets");
 148 SYSCTL_INT(_net_inet_carp, CARPCTL_PREEMPT, preempt, CTLFLAG_RW,
 149     &carp_opts[CARPCTL_PREEMPT], 0, "high-priority backup preemption mode");
 150 SYSCTL_INT(_net_inet_carp, CARPCTL_LOG, log, CTLFLAG_RW,
 151     &carp_opts[CARPCTL_LOG], 0, "log bad carp packets");
 152 SYSCTL_INT(_net_inet_carp, CARPCTL_ARPBALANCE, arpbalance, CTLFLAG_RW,
 153     &carp_opts[CARPCTL_ARPBALANCE], 0, "balance arp responses");
 154
 155 static int carp_suppress_preempt = 0;
 156 SYSCTL_INT(_net_inet_carp, OID_AUTO, suppress_preempt, CTLFLAG_RD,
 157     &carp_suppress_preempt, 0, "Preemption is suppressed");
 158
 159 static struct carpstats carpstats;
 160 SYSCTL_STRUCT(_net_inet_carp, CARPCTL_STATS, stats, CTLFLAG_RW,
 161     &carpstats, carpstats,
 162     "CARP statistics (struct carpstats, netinet/ip_carp.h)");
 163
 164 #define CARP_LOG(...)   do {                            \
 165         if (carp_opts[CARPCTL_LOG] > 0)                 \
 166                 log(LOG_INFO, __VA_ARGS__);             \
 167 } while (0)
 168
 169 #define CARP_DEBUG(...) do {                            \
 170         if (carp_opts[CARPCTL_LOG] > 1)                 \
 171                 log(LOG_DEBUG, __VA_ARGS__);            \
 172 } while (0)
 173
 174 static void     carp_hmac_prepare(struct carp_softc *);
 175 static void     carp_hmac_generate(struct carp_softc *, uint32_t *,
 176                     unsigned char *);
 177 static int      carp_hmac_verify(struct carp_softc *, uint32_t *,
 178                     unsigned char *);
 179 static void     carp_setroute(struct carp_softc *, int);
 180 static void     carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
 181 static int      carp_clone_create(struct if_clone *, int, caddr_t);
 182 static int      carp_clone_destroy(struct ifnet *);
 183 static void     carp_detach(struct carp_softc *, int);
 184 static int      carp_prepare_ad(struct mbuf *, struct carp_softc *,
 185                     struct carp_header *);
 186 static void     carp_send_ad_all(void);
 187 static void     carp_send_ad_timeout(void *);
 188 static void     carp_send_ad(struct carp_softc *);
 189 static void     carp_send_arp(struct carp_softc *);
 190 static void     carp_master_down_timeout(void *);
 191 static void     carp_master_down(struct carp_softc *);
 192 static int      carp_ioctl(struct ifnet *, u_long, caddr_t, struct ucred *);
 193 static int      carp_looutput(struct ifnet *, struct mbuf *, struct sockaddr *,
 194                     struct rtentry *);
 195 static void     carp_start(struct ifnet *);
 196 static void     carp_setrun(struct carp_softc *, sa_family_t);
 197 static void     carp_set_state(struct carp_softc *, int);
 198
 199 static void     carp_multicast_cleanup(struct carp_softc *);
 200 static void     carp_add_addr(struct carp_softc *, struct ifaddr *);
 201 static void     carp_del_addr(struct carp_softc *, struct ifaddr *);
 202 static void     carp_config_addr(struct carp_softc *, struct ifaddr *);
 203 static void     carp_link_addrs(struct carp_softc *, struct ifnet *,
 204                     struct ifaddr *);
 205 static void     carp_unlink_addrs(struct carp_softc *, struct ifnet *,
 206                     struct ifaddr *);
 207
 208 static int      carp_get_vhaddr(struct carp_softc *, struct ifdrv *);
 209 static int      carp_config_vhaddr(struct carp_softc *, struct carp_vhaddr *);
 210 static int      carp_activate_vhaddr(struct carp_softc *, struct carp_vhaddr *,
 211                     struct ifnet *, const struct in_ifaddr *, int);
 212 static void     carp_deactivate_vhaddr(struct carp_softc *,
 213                     struct carp_vhaddr *);
 214
 215 static void     carp_sc_state(struct carp_softc *);
 216 #ifdef INET6
 217 static void     carp_send_na(struct carp_softc *);
 218 static int      carp_set_addr6(struct carp_softc *, struct sockaddr_in6 *);
 219 static int      carp_del_addr6(struct carp_softc *, struct sockaddr_in6 *);
 220 static void     carp_multicast6_cleanup(struct carp_softc *);
 221 #endif
 222 static void     carp_stop(struct carp_softc *, int);
 223 static void     carp_reset(struct carp_softc *, int);
 224
 225 static void     carp_ifaddr(void *, struct ifnet *, enum ifaddr_event,
 226                             struct ifaddr *);
 227 static void     carp_ifdetach(void *, struct ifnet *);
 228
 229 static MALLOC_DEFINE(M_CARP, "CARP", "CARP interfaces");
 230
 231 static LIST_HEAD(, carp_softc) carpif_list;
 232
 233 static struct if_clone carp_cloner =
 234 IF_CLONE_INITIALIZER(CARP_IFNAME, carp_clone_create, carp_clone_destroy,
 235                      0, IF_MAXUNIT);
 236
 237 static eventhandler_tag carp_ifdetach_event;
 238 static eventhandler_tag carp_ifaddr_event;
 239
 240 static __inline void
 241 carp_insert_vhaddr(struct carp_softc *sc, struct carp_vhaddr *vha_new)
 242 {
 243         struct carp_vhaddr *vha;
 244         u_long new_addr, addr;
 245
 246         KKASSERT((vha_new->vha_flags & CARP_VHAF_ONLIST) == 0);
 247
 248         /*
 249          * Virtual address list is sorted; smaller one first
 250          */
 251         new_addr = ntohl(vha_new->vha_ia->ia_addr.sin_addr.s_addr);
 252
 253         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
 254                 addr = ntohl(vha->vha_ia->ia_addr.sin_addr.s_addr);
 255
 256                 if (addr > new_addr)
 257                         break;
 258         }
 259         if (vha == NULL)
 260                 TAILQ_INSERT_TAIL(&sc->sc_vha_list, vha_new, vha_link);
 261         else
 262                 TAILQ_INSERT_BEFORE(vha, vha_new, vha_link);
 263         vha_new->vha_flags |= CARP_VHAF_ONLIST;
 264 }
 265
 266 static __inline void
 267 carp_remove_vhaddr(struct carp_softc *sc, struct carp_vhaddr *vha)
 268 {
 269         KKASSERT(vha->vha_flags & CARP_VHAF_ONLIST);
 270         vha->vha_flags &= ~CARP_VHAF_ONLIST;
 271         TAILQ_REMOVE(&sc->sc_vha_list, vha, vha_link);
 272 }
 273
 274 static void
 275 carp_hmac_prepare(struct carp_softc *sc)
 276 {
 277         uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
 278         uint8_t vhid = sc->sc_vhid & 0xff;
 279         int i;
 280 #ifdef INET6
 281         struct ifaddr_container *ifac;
 282         struct in6_addr in6;
 283 #endif
 284 #ifdef INET
 285         struct carp_vhaddr *vha;
 286 #endif
 287
 288         /* XXX: possible race here */
 289
 290         /* compute ipad from key */
 291         bzero(sc->sc_pad, sizeof(sc->sc_pad));
 292         bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
 293         for (i = 0; i < sizeof(sc->sc_pad); i++)
 294                 sc->sc_pad[i] ^= 0x36;
 295
 296         /* precompute first part of inner hash */
 297         SHA1Init(&sc->sc_sha1);
 298         SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
 299         SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
 300         SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
 301         SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
 302 #ifdef INET
 303         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
 304                 SHA1Update(&sc->sc_sha1,
 305                     (const uint8_t *)&vha->vha_ia->ia_addr.sin_addr,
 306                     sizeof(struct in_addr));
 307         }
 308 #endif /* INET */
 309 #ifdef INET6
 310         TAILQ_FOREACH(ifac, &sc->sc_if.if_addrheads[mycpuid], ifa_link) {
 311                 struct ifaddr *ifa = ifac->ifa;
 312
 313                 if (ifa->ifa_addr->sa_family == AF_INET6) {
 314                         in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
 315                         in6_clearscope(&in6);
 316                         SHA1Update(&sc->sc_sha1, (void *)&in6, sizeof(in6));
 317                 }
 318         }
 319 #endif /* INET6 */
 320
 321         /* convert ipad to opad */
 322         for (i = 0; i < sizeof(sc->sc_pad); i++)
 323                 sc->sc_pad[i] ^= 0x36 ^ 0x5c;
 324 }
 325
 326 static void
 327 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
 328     unsigned char md[20])
 329 {
 330         SHA1_CTX sha1ctx;
 331
 332         /* fetch first half of inner hash */
 333         bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
 334
 335         SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
 336         SHA1Final(md, &sha1ctx);
 337
 338         /* outer hash */
 339         SHA1Init(&sha1ctx);
 340         SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
 341         SHA1Update(&sha1ctx, md, 20);
 342         SHA1Final(md, &sha1ctx);
 343 }
 344
 345 static int
 346 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
 347     unsigned char md[20])
 348 {
 349         unsigned char md2[20];
 350
 351         carp_hmac_generate(sc, counter, md2);
 352         return (bcmp(md, md2, sizeof(md2)));
 353 }
 354
 355 static void
 356 carp_setroute(struct carp_softc *sc, int cmd)
 357 {
 358 #ifdef INET6
 359         struct ifaddr_container *ifac;
 360
 361         crit_enter();
 362         TAILQ_FOREACH(ifac, &sc->sc_if.if_addrheads[mycpuid], ifa_link) {
 363                 struct ifaddr *ifa = ifac->ifa;
 364
 365                 if (ifa->ifa_addr->sa_family == AF_INET6) {
 366                         if (cmd == RTM_ADD)
 367                                 in6_ifaddloop(ifa);
 368                         else
 369                                 in6_ifremloop(ifa);
 370                 }
 371         }
 372         crit_exit();
 373 #endif /* INET6 */
 374 }
 375
 376 static int
 377 carp_clone_create(struct if_clone *ifc, int unit, caddr_t param __unused)
 378 {
 379         struct carp_softc *sc;
 380         struct ifnet *ifp;
 381
 382         sc = kmalloc(sizeof(*sc), M_CARP, M_WAITOK | M_ZERO);
 383         ifp = &sc->sc_if;
 384
 385         sc->sc_suppress = 0;
 386         sc->sc_advbase = CARP_DFLTINTV;
 387         sc->sc_vhid = -1;       /* required setting */
 388         sc->sc_advskew = 0;
 389         sc->sc_init_counter = 1;
 390         sc->sc_naddrs = 0;
 391         sc->sc_naddrs6 = 0;
 392
 393         TAILQ_INIT(&sc->sc_vha_list);
 394
 395 #ifdef INET6
 396         sc->sc_im6o.im6o_multicast_hlim = CARP_DFLTTL;
 397 #endif
 398
 399         callout_init(&sc->sc_ad_tmo);
 400         callout_init(&sc->sc_md_tmo);
 401         callout_init(&sc->sc_md6_tmo);
 402
 403         ifp->if_softc = sc;
 404         if_initname(ifp, CARP_IFNAME, unit);
 405         ifp->if_mtu = ETHERMTU;
 406         ifp->if_flags = IFF_LOOPBACK;
 407         ifp->if_ioctl = carp_ioctl;
 408         ifp->if_output = carp_looutput;
 409         ifp->if_start = carp_start;
 410         ifp->if_type = IFT_CARP;
 411         ifp->if_snd.ifq_maxlen = ifqmaxlen;
 412         ifp->if_hdrlen = 0;
 413         if_attach(ifp, NULL);
 414         bpfattach(ifp, DLT_NULL, sizeof(u_int));
 415
 416         crit_enter();
 417         LIST_INSERT_HEAD(&carpif_list, sc, sc_next);
 418         crit_exit();
 419
 420         return (0);
 421 }
 422
 423 static int
 424 carp_clone_destroy(struct ifnet *ifp)
 425 {
 426         struct carp_softc *sc = ifp->if_softc;
 427
 428         sc->sc_dead = 1;
 429         carp_detach(sc, 1);
 430
 431         crit_enter();
 432         LIST_REMOVE(sc, sc_next);
 433         crit_exit();
 434         bpfdetach(ifp);
 435         if_detach(ifp);
 436
 437         KASSERT(sc->sc_naddrs == 0, ("certain inet address is still active\n"));
 438         kfree(sc, M_CARP);
 439
 440         return 0;
 441 }
 442
 443 static void
 444 carp_detach(struct carp_softc *sc, int detach)
 445 {
 446         struct carp_if *cif;
 447
 448         carp_reset(sc, detach);
 449
 450         carp_multicast_cleanup(sc);
 451 #ifdef INET6
 452         carp_multicast6_cleanup(sc);
 453 #endif
 454
 455         if (!sc->sc_dead && detach) {
 456                 struct carp_vhaddr *vha;
 457
 458                 TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link)
 459                         carp_deactivate_vhaddr(sc, vha);
 460                 KKASSERT(sc->sc_naddrs == 0);
 461         }
 462
 463         if (sc->sc_carpdev != NULL) {
 464                 cif = sc->sc_carpdev->if_carp;
 465                 TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
 466                 if (TAILQ_EMPTY(&cif->vhif_vrs)) {
 467                         ifpromisc(sc->sc_carpdev, 0);
 468                         sc->sc_carpdev->if_carp = NULL;
 469                         kfree(cif, M_CARP);
 470                 }
 471                 sc->sc_carpdev = NULL;
 472                 sc->sc_ia = NULL;
 473         }
 474 }
 475
 476 /* Detach an interface from the carp. */
 477 static void
 478 carp_ifdetach(void *arg __unused, struct ifnet *ifp)
 479 {
 480         struct carp_if *cif = ifp->if_carp;
 481         struct carp_softc *sc;
 482
 483         while (ifp->if_carp &&
 484                (sc = TAILQ_FIRST(&cif->vhif_vrs)) != NULL)
 485                 carp_detach(sc, 1);
 486 }
 487
 488 /*
 489  * process input packet.
 490  * we have rearranged checks order compared to the rfc,
 491  * but it seems more efficient this way or not possible otherwise.
 492  */
 493 int
 494 carp_input(struct mbuf **mp, int *offp, int proto)
 495 {
 496         struct mbuf *m = *mp;
 497         struct ip *ip = mtod(m, struct ip *);
 498         struct carp_header *ch;
 499         int len, iphlen;
 500
 501         iphlen = *offp;
 502         *mp = NULL;
 503
 504         carpstats.carps_ipackets++;
 505
 506         if (!carp_opts[CARPCTL_ALLOW]) {
 507                 m_freem(m);
 508                 return(IPPROTO_DONE);
 509         }
 510
 511         /* Check if received on a valid carp interface */
 512         if (m->m_pkthdr.rcvif->if_carp == NULL) {
 513                 carpstats.carps_badif++;
 514                 CARP_LOG("carp_input: packet received on non-carp "
 515                     "interface: %s\n",
 516                     m->m_pkthdr.rcvif->if_xname);
 517                 m_freem(m);
 518                 return(IPPROTO_DONE);
 519         }
 520
 521         /* Verify that the IP TTL is CARP_DFLTTL. */
 522         if (ip->ip_ttl != CARP_DFLTTL) {
 523                 carpstats.carps_badttl++;
 524                 CARP_LOG("carp_input: received ttl %d != %d on %s\n",
 525                     ip->ip_ttl, CARP_DFLTTL,
 526                     m->m_pkthdr.rcvif->if_xname);
 527                 m_freem(m);
 528                 return(IPPROTO_DONE);
 529         }
 530
 531         /* Minimal CARP packet size */
 532         len = iphlen + sizeof(*ch);
 533
 534         /*
 535          * Verify that the received packet length is
 536          * not less than the CARP header
 537          */
 538         if (m->m_pkthdr.len < len) {
 539                 carpstats.carps_badlen++;
 540                 CARP_LOG("packet too short %d on %s\n", m->m_pkthdr.len,
 541                          m->m_pkthdr.rcvif->if_xname);
 542                 m_freem(m);
 543                 return(IPPROTO_DONE);
 544         }
 545
 546         /* Make sure that CARP header is contiguous */
 547         if (len > m->m_len) {
 548                 m = m_pullup(m, len);
 549                 if (m == NULL) {
 550                         carpstats.carps_hdrops++;
 551                         CARP_LOG("carp_input: m_pullup failed\n");
 552                         return(IPPROTO_DONE);
 553                 }
 554                 ip = mtod(m, struct ip *);
 555         }
 556         ch = (struct carp_header *)((uint8_t *)ip + iphlen);
 557
 558         /* Verify the CARP checksum */
 559         if (in_cksum_skip(m, len, iphlen)) {
 560                 carpstats.carps_badsum++;
 561                 CARP_LOG("carp_input: checksum failed on %s\n",
 562                     m->m_pkthdr.rcvif->if_xname);
 563                 m_freem(m);
 564                 return(IPPROTO_DONE);
 565         }
 566         carp_input_c(m, ch, AF_INET);
 567         return(IPPROTO_DONE);
 568 }
 569
 570 #ifdef INET6
 571 int
 572 carp6_input(struct mbuf **mp, int *offp, int proto)
 573 {
 574         struct mbuf *m = *mp;
 575         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 576         struct carp_header *ch;
 577         u_int len;
 578
 579         carpstats.carps_ipackets6++;
 580
 581         if (!carp_opts[CARPCTL_ALLOW]) {
 582                 m_freem(m);
 583                 return (IPPROTO_DONE);
 584         }
 585
 586         /* check if received on a valid carp interface */
 587         if (m->m_pkthdr.rcvif->if_carp == NULL) {
 588                 carpstats.carps_badif++;
 589                 CARP_LOG("carp6_input: packet received on non-carp "
 590                     "interface: %s\n",
 591                     m->m_pkthdr.rcvif->if_xname);
 592                 m_freem(m);
 593                 return (IPPROTO_DONE);
 594         }
 595
 596         /* verify that the IP TTL is 255 */
 597         if (ip6->ip6_hlim != CARP_DFLTTL) {
 598                 carpstats.carps_badttl++;
 599                 CARP_LOG("carp6_input: received ttl %d != 255 on %s\n",
 600                     ip6->ip6_hlim,
 601                     m->m_pkthdr.rcvif->if_xname);
 602                 m_freem(m);
 603                 return (IPPROTO_DONE);
 604         }
 605
 606         /* verify that we have a complete carp packet */
 607         len = m->m_len;
 608         IP6_EXTHDR_GET(ch, struct carp_header *, m, *offp, sizeof(*ch));
 609         if (ch == NULL) {
 610                 carpstats.carps_badlen++;
 611                 CARP_LOG("carp6_input: packet size %u too small\n", len);
 612                 return (IPPROTO_DONE);
 613         }
 614
 615         /* verify the CARP checksum */
 616         if (in_cksum_range(m, 0, *offp, sizeof(*ch))) {
 617                 carpstats.carps_badsum++;
 618                 CARP_LOG("carp6_input: checksum failed, on %s\n",
 619                     m->m_pkthdr.rcvif->if_xname);
 620                 m_freem(m);
 621                 return (IPPROTO_DONE);
 622         }
 623
 624         carp_input_c(m, ch, AF_INET6);
 625         return (IPPROTO_DONE);
 626 }
 627 #endif /* INET6 */
 628
 629 static void
 630 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
 631 {
 632         struct ifnet *ifp = m->m_pkthdr.rcvif;
 633         struct ifnet *cifp;
 634         struct carp_softc *sc;
 635         uint64_t tmp_counter;
 636         struct timeval sc_tv, ch_tv;
 637
 638         /* verify that the VHID is valid on the receiving interface */
 639         TAILQ_FOREACH(sc, &((struct carp_if *)ifp->if_carp)->vhif_vrs, sc_list)
 640                 if (sc->sc_vhid == ch->carp_vhid)
 641                         break;
 642
 643         if (!sc || !CARP_IS_RUNNING(&sc->sc_if)) {
 644                 carpstats.carps_badvhid++;
 645                 m_freem(m);
 646                 return;
 647         }
 648         cifp = &sc->sc_if;
 649
 650         getmicrotime(&cifp->if_lastchange);
 651         cifp->if_ipackets++;
 652         cifp->if_ibytes += m->m_pkthdr.len;
 653
 654         if (cifp->if_bpf) {
 655                 struct ip *ip = mtod(m, struct ip *);
 656
 657                 /* BPF wants net byte order */
 658                 ip->ip_len = htons(ip->ip_len + (ip->ip_hl << 2));
 659                 ip->ip_off = htons(ip->ip_off);
 660                 bpf_mtap(cifp->if_bpf, m);
 661         }
 662
 663         /* verify the CARP version. */
 664         if (ch->carp_version != CARP_VERSION) {
 665                 carpstats.carps_badver++;
 666                 cifp->if_ierrors++;
 667                 CARP_LOG("%s; invalid version %d\n", cifp->if_xname,
 668                          ch->carp_version);
 669                 m_freem(m);
 670                 return;
 671         }
 672
 673         /* verify the hash */
 674         if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
 675                 carpstats.carps_badauth++;
 676                 cifp->if_ierrors++;
 677                 CARP_LOG("%s: incorrect hash\n", cifp->if_xname);
 678                 m_freem(m);
 679                 return;
 680         }
 681
 682         tmp_counter = ntohl(ch->carp_counter[0]);
 683         tmp_counter = tmp_counter<<32;
 684         tmp_counter += ntohl(ch->carp_counter[1]);
 685
 686         /* XXX Replay protection goes here */
 687
 688         sc->sc_init_counter = 0;
 689         sc->sc_counter = tmp_counter;
 690
 691         sc_tv.tv_sec = sc->sc_advbase;
 692         if (carp_suppress_preempt && sc->sc_advskew <  240)
 693                 sc_tv.tv_usec = 240 * 1000000 / 256;
 694         else
 695                 sc_tv.tv_usec = sc->sc_advskew * 1000000 / 256;
 696         ch_tv.tv_sec = ch->carp_advbase;
 697         ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
 698
 699         switch (sc->sc_state) {
 700         case INIT:
 701                 break;
 702
 703         case MASTER:
 704                 /*
 705                  * If we receive an advertisement from a master who's going to
 706                  * be more frequent than us, go into BACKUP state.
 707                  */
 708                 if (timevalcmp(&sc_tv, &ch_tv, >) ||
 709                     timevalcmp(&sc_tv, &ch_tv, ==)) {
 710                         callout_stop(&sc->sc_ad_tmo);
 711                         CARP_DEBUG("%s: MASTER -> BACKUP "
 712                            "(more frequent advertisement received)\n",
 713                            cifp->if_xname);
 714                         carp_set_state(sc, BACKUP);
 715                         carp_setrun(sc, 0);
 716                         carp_setroute(sc, RTM_DELETE);
 717                 }
 718                 break;
 719
 720         case BACKUP:
 721                 /*
 722                  * If we're pre-empting masters who advertise slower than us,
 723                  * and this one claims to be slower, treat him as down.
 724                  */
 725                 if (carp_opts[CARPCTL_PREEMPT] &&
 726                     timevalcmp(&sc_tv, &ch_tv, <)) {
 727                         CARP_DEBUG("%s: BACKUP -> MASTER "
 728                             "(preempting a slower master)\n", cifp->if_xname);
 729                         carp_master_down(sc);
 730                         break;
 731                 }
 732
 733                 /*
 734                  *  If the master is going to advertise at such a low frequency
 735                  *  that he's guaranteed to time out, we'd might as well just
 736                  *  treat him as timed out now.
 737                  */
 738                 sc_tv.tv_sec = sc->sc_advbase * 3;
 739                 if (timevalcmp(&sc_tv, &ch_tv, <)) {
 740                         CARP_DEBUG("%s: BACKUP -> MASTER (master timed out)\n",
 741                                    cifp->if_xname);
 742                         carp_master_down(sc);
 743                         break;
 744                 }
 745
 746                 /*
 747                  * Otherwise, we reset the counter and wait for the next
 748                  * advertisement.
 749                  */
 750                 carp_setrun(sc, af);
 751                 break;
 752         }
 753         m_freem(m);
 754 }
 755
 756 static int
 757 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
 758 {
 759         struct ifnet *cifp = &sc->sc_if;
 760         struct m_tag *mtag;
 761
 762         if (sc->sc_init_counter) {
 763                 /* this could also be seconds since unix epoch */
 764                 sc->sc_counter = karc4random();
 765                 sc->sc_counter = sc->sc_counter << 32;
 766                 sc->sc_counter += karc4random();
 767         } else {
 768                 sc->sc_counter++;
 769         }
 770
 771         ch->carp_counter[0] = htonl((sc->sc_counter >> 32) & 0xffffffff);
 772         ch->carp_counter[1] = htonl(sc->sc_counter & 0xffffffff);
 773
 774         carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
 775
 776         /* Tag packet for carp_output */
 777         mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct ifnet *), MB_DONTWAIT);
 778         if (mtag == NULL) {
 779                 m_freem(m);
 780                 cifp->if_oerrors++;
 781                 return ENOMEM;
 782         }
 783         bcopy(&cifp, (caddr_t)(mtag + 1), sizeof(struct ifnet *));
 784         m_tag_prepend(m, mtag);
 785
 786         return 0;
 787 }
 788
 789 static void
 790 carp_send_ad_all(void)
 791 {
 792         struct carp_softc *sc;
 793
 794         LIST_FOREACH(sc, &carpif_list, sc_next) {
 795                 if (sc->sc_carpdev == NULL)
 796                         continue;
 797
 798                 if (CARP_IS_RUNNING(&sc->sc_if) && sc->sc_state == MASTER)
 799                         carp_send_ad(sc);
 800         }
 801 }
 802
 803 static void
 804 carp_send_ad_timeout(void *xsc)
 805 {
 806         carp_send_ad(xsc);
 807 }
 808
 809 static void
 810 carp_send_ad(struct carp_softc *sc)
 811 {
 812         struct ifnet *cifp = &sc->sc_if;
 813         struct carp_header ch;
 814         struct timeval tv;
 815         struct carp_header *ch_ptr;
 816         struct mbuf *m;
 817         int len, advbase, advskew;
 818
 819         if (!CARP_IS_RUNNING(cifp)) {
 820                 /* Bow out */
 821                 advbase = 255;
 822                 advskew = 255;
 823         } else {
 824                 advbase = sc->sc_advbase;
 825                 if (!carp_suppress_preempt || sc->sc_advskew > 240)
 826                         advskew = sc->sc_advskew;
 827                 else
 828                         advskew = 240;
 829                 tv.tv_sec = advbase;
 830                 tv.tv_usec = advskew * 1000000 / 256;
 831         }
 832
 833         ch.carp_version = CARP_VERSION;
 834         ch.carp_type = CARP_ADVERTISEMENT;
 835         ch.carp_vhid = sc->sc_vhid;
 836         ch.carp_advbase = advbase;
 837         ch.carp_advskew = advskew;
 838         ch.carp_authlen = 7;    /* XXX DEFINE */
 839         ch.carp_pad1 = 0;       /* must be zero */
 840         ch.carp_cksum = 0;
 841
 842 #ifdef INET
 843         if (sc->sc_ia != NULL) {
 844                 struct ip *ip;
 845
 846                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
 847                 if (m == NULL) {
 848                         cifp->if_oerrors++;
 849                         carpstats.carps_onomem++;
 850                         /* XXX maybe less ? */
 851                         if (advbase != 255 || advskew != 255)
 852                                 callout_reset(&sc->sc_ad_tmo, tvtohz_high(&tv),
 853                                     carp_send_ad_timeout, sc);
 854                         return;
 855                 }
 856                 len = sizeof(*ip) + sizeof(ch);
 857                 m->m_pkthdr.len = len;
 858                 m->m_pkthdr.rcvif = NULL;
 859                 m->m_len = len;
 860                 MH_ALIGN(m, m->m_len);
 861                 m->m_flags |= M_MCAST;
 862                 ip = mtod(m, struct ip *);
 863                 ip->ip_v = IPVERSION;
 864                 ip->ip_hl = sizeof(*ip) >> 2;
 865                 ip->ip_tos = IPTOS_LOWDELAY;
 866                 ip->ip_len = len;
 867                 ip->ip_id = ip_newid();
 868                 ip->ip_off = IP_DF;
 869                 ip->ip_ttl = CARP_DFLTTL;
 870                 ip->ip_p = IPPROTO_CARP;
 871                 ip->ip_sum = 0;
 872                 ip->ip_src = sc->sc_ia->ia_addr.sin_addr;
 873                 ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
 874
 875                 ch_ptr = (struct carp_header *)(&ip[1]);
 876                 bcopy(&ch, ch_ptr, sizeof(ch));
 877                 if (carp_prepare_ad(m, sc, ch_ptr))
 878                         return;
 879                 ch_ptr->carp_cksum = in_cksum_skip(m, len, sizeof(*ip));
 880
 881                 getmicrotime(&cifp->if_lastchange);
 882                 cifp->if_opackets++;
 883                 cifp->if_obytes += len;
 884                 carpstats.carps_opackets++;
 885
 886                 if (ip_output(m, NULL, NULL, IP_RAWOUTPUT, &sc->sc_imo, NULL)) {
 887                         cifp->if_oerrors++;
 888                         if (sc->sc_sendad_errors < INT_MAX)
 889                                 sc->sc_sendad_errors++;
 890                         if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
 891                                 carp_suppress_preempt++;
 892                                 if (carp_suppress_preempt == 1) {
 893                                         carp_send_ad_all();
 894                                 }
 895                         }
 896                         sc->sc_sendad_success = 0;
 897                 } else {
 898                         if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
 899                                 if (++sc->sc_sendad_success >=
 900                                     CARP_SENDAD_MIN_SUCCESS) {
 901                                         carp_suppress_preempt--;
 902                                         sc->sc_sendad_errors = 0;
 903                                 }
 904                         } else {
 905                                 sc->sc_sendad_errors = 0;
 906                         }
 907                 }
 908         }
 909 #endif /* INET */
 910 #ifdef INET6
 911         if (sc->sc_ia6) {
 912                 struct ip6_hdr *ip6;
 913
 914                 MGETHDR(m, MB_DONTWAIT, MT_HEADER);
 915                 if (m == NULL) {
 916                         cifp->if_oerrors++;
 917                         carpstats.carps_onomem++;
 918                         /* XXX maybe less ? */
 919                         if (advbase != 255 || advskew != 255)
 920                                 callout_reset(&sc->sc_ad_tmo, tvtohz_high(&tv),
 921                                     carp_send_ad_timeout, sc);
 922                         return;
 923                 }
 924                 len = sizeof(*ip6) + sizeof(ch);
 925                 m->m_pkthdr.len = len;
 926                 m->m_pkthdr.rcvif = NULL;
 927                 m->m_len = len;
 928                 MH_ALIGN(m, m->m_len);
 929                 m->m_flags |= M_MCAST;
 930                 ip6 = mtod(m, struct ip6_hdr *);
 931                 bzero(ip6, sizeof(*ip6));
 932                 ip6->ip6_vfc |= IPV6_VERSION;
 933                 ip6->ip6_hlim = CARP_DFLTTL;
 934                 ip6->ip6_nxt = IPPROTO_CARP;
 935                 bcopy(&sc->sc_ia6->ia_addr.sin6_addr, &ip6->ip6_src,
 936                     sizeof(struct in6_addr));
 937                 /* set the multicast destination */
 938
 939                 ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
 940                 ip6->ip6_dst.s6_addr8[15] = 0x12;
 941                 if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
 942                         cifp->if_oerrors++;
 943                         m_freem(m);
 944                         CARP_LOG("%s: in6_setscope failed\n", __func__);
 945                         return;
 946                 }
 947
 948                 ch_ptr = (struct carp_header *)(&ip6[1]);
 949                 bcopy(&ch, ch_ptr, sizeof(ch));
 950                 if (carp_prepare_ad(m, sc, ch_ptr))
 951                         return;
 952                 ch_ptr->carp_cksum = in_cksum_skip(m, len, sizeof(*ip6));
 953
 954                 getmicrotime(&cifp->if_lastchange);
 955                 cifp->if_opackets++;
 956                 cifp->if_obytes += len;
 957                 carpstats.carps_opackets6++;
 958
 959                 if (ip6_output(m, NULL, NULL, 0, &sc->sc_im6o, NULL, NULL)) {
 960                         cifp->if_oerrors++;
 961                         if (sc->sc_sendad_errors < INT_MAX)
 962                                 sc->sc_sendad_errors++;
 963                         if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
 964                                 carp_suppress_preempt++;
 965                                 if (carp_suppress_preempt == 1) {
 966                                         carp_send_ad_all();
 967                                 }
 968                         }
 969                         sc->sc_sendad_success = 0;
 970                 } else {
 971                         if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
 972                                 if (++sc->sc_sendad_success >=
 973                                     CARP_SENDAD_MIN_SUCCESS) {
 974                                         carp_suppress_preempt--;
 975                                         sc->sc_sendad_errors = 0;
 976                                 }
 977                         } else {
 978                                 sc->sc_sendad_errors = 0;
 979                         }
 980                 }
 981         }
 982 #endif /* INET6 */
 983
 984         if (advbase != 255 || advskew != 255)
 985                 callout_reset(&sc->sc_ad_tmo, tvtohz_high(&tv),
 986                     carp_send_ad_timeout, sc);
 987 }
 988
 989 /*
 990  * Broadcast a gratuitous ARP request containing
 991  * the virtual router MAC address for each IP address
 992  * associated with the virtual router.
 993  */
 994 static void
 995 carp_send_arp(struct carp_softc *sc)
 996 {
 997         const struct carp_vhaddr *vha;
 998
 999         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
1000                 if (vha->vha_iaback == NULL)
1001                         continue;
1002
1003                 arp_iainit(sc->sc_carpdev, &vha->vha_ia->ia_addr.sin_addr,
1004                            IF_LLADDR(&sc->sc_if));
1005         }
1006 }
1007
1008 #ifdef INET6
1009 static void
1010 carp_send_na(struct carp_softc *sc)
1011 {
1012         struct ifaddr_container *ifac;
1013         struct in6_addr *in6;
1014         static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1015
1016         TAILQ_FOREACH(ifac, &sc->sc_if.if_addrheads[mycpuid], ifa_link) {
1017                 struct ifaddr *ifa = ifac->ifa;
1018
1019                 if (ifa->ifa_addr->sa_family != AF_INET6)
1020                         continue;
1021
1022                 in6 = &ifatoia6(ifa)->ia_addr.sin6_addr;
1023                 nd6_na_output(sc->sc_carpdev, &mcast, in6,
1024                     ND_NA_FLAG_OVERRIDE, 1, NULL);
1025                 DELAY(1000);    /* XXX */
1026         }
1027 }
1028 #endif /* INET6 */
1029
1030 static __inline const struct carp_vhaddr *
1031 carp_find_addr(const struct carp_softc *sc, const struct in_addr *addr)
1032 {
1033         struct carp_vhaddr *vha;
1034
1035         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
1036                 if (vha->vha_iaback == NULL)
1037                         continue;
1038
1039                 if (vha->vha_ia->ia_addr.sin_addr.s_addr == addr->s_addr)
1040                         return vha;
1041         }
1042         return NULL;
1043 }
1044
1045 static int
1046 carp_iamatch_balance(const struct carp_if *cif, const struct in_addr *itaddr,
1047                      const struct in_addr *isaddr, uint8_t **enaddr)
1048 {
1049         const struct carp_softc *vh;
1050         int index, count = 0;
1051
1052         /*
1053          * XXX proof of concept implementation.
1054          * We use the source ip to decide which virtual host should
1055          * handle the request. If we're master of that virtual host,
1056          * then we respond, otherwise, just drop the arp packet on
1057          * the floor.
1058          */
1059
1060         TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1061                 if (!CARP_IS_RUNNING(&vh->sc_if))
1062                         continue;
1063
1064                 if (carp_find_addr(vh, itaddr) != NULL)
1065                         count++;
1066         }
1067         if (count == 0)
1068                 return 0;
1069
1070         /* this should be a hash, like pf_hash() */
1071         index = ntohl(isaddr->s_addr) % count;
1072         count = 0;
1073
1074         TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1075                 if (!CARP_IS_RUNNING(&vh->sc_if))
1076                         continue;
1077
1078                 if (carp_find_addr(vh, itaddr) == NULL)
1079                         continue;
1080
1081                 if (count == index) {
1082                         if (vh->sc_state == MASTER) {
1083                                 *enaddr = IF_LLADDR(&vh->sc_if);
1084                                 return 1;
1085                         } else {
1086                                 return 0;
1087                         }
1088                 }
1089                 count++;
1090         }
1091         return 0;
1092 }
1093
1094 int
1095 carp_iamatch(const void *v, const struct in_addr *itaddr,
1096              const struct in_addr *isaddr, uint8_t **enaddr)
1097 {
1098         const struct carp_if *cif = v;
1099         const struct carp_softc *vh;
1100
1101         if (carp_opts[CARPCTL_ARPBALANCE])
1102                 return carp_iamatch_balance(cif, itaddr, isaddr, enaddr);
1103
1104         TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1105                 if (!CARP_IS_RUNNING(&vh->sc_if) || vh->sc_state != MASTER)
1106                         continue;
1107
1108                 if (carp_find_addr(vh, itaddr) != NULL) {
1109                         *enaddr = IF_LLADDR(&vh->sc_if);
1110                         return 1;
1111                 }
1112         }
1113         return 0;
1114 }
1115
1116 #ifdef INET6
1117 struct ifaddr *
1118 carp_iamatch6(void *v, struct in6_addr *taddr)
1119 {
1120         struct carp_if *cif = v;
1121         struct carp_softc *vh;
1122
1123         TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1124                 struct ifaddr_container *ifac;
1125
1126                 TAILQ_FOREACH(ifac, &vh->sc_if.if_addrheads[mycpuid],
1127                               ifa_link) {
1128                         struct ifaddr *ifa = ifac->ifa;
1129
1130                         if (IN6_ARE_ADDR_EQUAL(taddr,
1131                             &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1132                             CARP_IS_RUNNING(&vh->sc_if) &&
1133                             vh->sc_state == MASTER) {
1134                                 return (ifa);
1135                         }
1136                 }
1137         }
1138         return (NULL);
1139 }
1140
1141 void *
1142 carp_macmatch6(void *v, struct mbuf *m, const struct in6_addr *taddr)
1143 {
1144         struct m_tag *mtag;
1145         struct carp_if *cif = v;
1146         struct carp_softc *sc;
1147
1148         TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list) {
1149                 struct ifaddr_container *ifac;
1150
1151                 TAILQ_FOREACH(ifac, &sc->sc_if.if_addrheads[mycpuid],
1152                               ifa_link) {
1153                         struct ifaddr *ifa = ifac->ifa;
1154
1155                         if (IN6_ARE_ADDR_EQUAL(taddr,
1156                             &ifatoia6(ifa)->ia_addr.sin6_addr) &&
1157                             CARP_IS_RUNNING(&sc->sc_if)) {
1158                                 struct ifnet *ifp = &sc->sc_if;
1159
1160                                 mtag = m_tag_get(PACKET_TAG_CARP,
1161                                     sizeof(struct ifnet *), MB_DONTWAIT);
1162                                 if (mtag == NULL) {
1163                                         /* better a bit than nothing */
1164                                         return (IF_LLADDR(ifp));
1165                                 }
1166                                 bcopy(&ifp, (caddr_t)(mtag + 1),
1167                                     sizeof(struct ifnet *));
1168                                 m_tag_prepend(m, mtag);
1169
1170                                 return (IF_LLADDR(ifp));
1171                         }
1172                 }
1173         }
1174         return (NULL);
1175 }
1176 #endif
1177
1178 int
1179 carp_forus(const void *v, const void *dhost)
1180 {
1181         const struct carp_if *cif = v;
1182         const struct carp_softc *vh;
1183         const uint8_t *ena = dhost;
1184
1185         if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1186                 return 0;
1187
1188         TAILQ_FOREACH(vh, &cif->vhif_vrs, sc_list) {
1189                 const struct ifnet *cifp = &vh->sc_if;
1190
1191                 if (CARP_IS_RUNNING(cifp) && vh->sc_state == MASTER &&
1192                     !bcmp(dhost, IF_LLADDR(cifp), ETHER_ADDR_LEN))
1193                         return 1;
1194         }
1195         return 0;
1196 }
1197
1198 static void
1199 carp_master_down_timeout(void *xsc)
1200 {
1201         struct carp_softc *sc = xsc;
1202
1203         CARP_DEBUG("%s: BACKUP -> MASTER (master timed out)\n",
1204                    sc->sc_if.if_xname);
1205         carp_master_down(sc);
1206 }
1207
1208 static void
1209 carp_master_down(struct carp_softc *sc)
1210 {
1211         switch (sc->sc_state) {
1212         case INIT:
1213                 kprintf("%s: master_down event in INIT state\n",
1214                         sc->sc_if.if_xname);
1215                 break;
1216
1217         case MASTER:
1218                 break;
1219
1220         case BACKUP:
1221                 carp_set_state(sc, MASTER);
1222                 carp_send_ad(sc);
1223                 carp_send_arp(sc);
1224 #ifdef INET6
1225                 carp_send_na(sc);
1226 #endif /* INET6 */
1227                 carp_setrun(sc, 0);
1228                 carp_setroute(sc, RTM_ADD);
1229                 break;
1230         }
1231 }
1232
1233 /*
1234  * When in backup state, af indicates whether to reset the master down timer
1235  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1236  */
1237 static void
1238 carp_setrun(struct carp_softc *sc, sa_family_t af)
1239 {
1240         struct ifnet *cifp = &sc->sc_if;
1241         struct timeval tv;
1242
1243         if (sc->sc_carpdev == NULL) {
1244                 carp_set_state(sc, INIT);
1245                 return;
1246         }
1247
1248         if ((cifp->if_flags & IFF_RUNNING) && sc->sc_vhid > 0 &&
1249             (sc->sc_naddrs || sc->sc_naddrs6)) {
1250                 /* Nothing */
1251         } else {
1252                 carp_setroute(sc, RTM_DELETE);
1253                 return;
1254         }
1255
1256         switch (sc->sc_state) {
1257         case INIT:
1258                 if (carp_opts[CARPCTL_PREEMPT] && !carp_suppress_preempt) {
1259                         carp_send_ad(sc);
1260                         carp_send_arp(sc);
1261 #ifdef INET6
1262                         carp_send_na(sc);
1263 #endif /* INET6 */
1264                         CARP_DEBUG("%s: INIT -> MASTER (preempting)\n",
1265                                    cifp->if_xname);
1266                         carp_set_state(sc, MASTER);
1267                         carp_setroute(sc, RTM_ADD);
1268                 } else {
1269                         CARP_DEBUG("%s: INIT -> BACKUP\n", cifp->if_xname);
1270                         carp_set_state(sc, BACKUP);
1271                         carp_setroute(sc, RTM_DELETE);
1272                         carp_setrun(sc, 0);
1273                 }
1274                 break;
1275
1276         case BACKUP:
1277                 callout_stop(&sc->sc_ad_tmo);
1278                 tv.tv_sec = 3 * sc->sc_advbase;
1279                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1280                 switch (af) {
1281 #ifdef INET
1282                 case AF_INET:
1283                         callout_reset(&sc->sc_md_tmo, tvtohz_high(&tv),
1284                             carp_master_down_timeout, sc);
1285                         break;
1286 #endif /* INET */
1287 #ifdef INET6
1288                 case AF_INET6:
1289                         callout_reset(&sc->sc_md6_tmo, tvtohz_high(&tv),
1290                             carp_master_down_timeout, sc);
1291                         break;
1292 #endif /* INET6 */
1293                 default:
1294                         if (sc->sc_naddrs)
1295                                 callout_reset(&sc->sc_md_tmo, tvtohz_high(&tv),
1296                                     carp_master_down_timeout, sc);
1297                         if (sc->sc_naddrs6)
1298                                 callout_reset(&sc->sc_md6_tmo, tvtohz_high(&tv),
1299                                     carp_master_down_timeout, sc);
1300                         break;
1301                 }
1302                 break;
1303
1304         case MASTER:
1305                 tv.tv_sec = sc->sc_advbase;
1306                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1307                 callout_reset(&sc->sc_ad_tmo, tvtohz_high(&tv),
1308                     carp_send_ad_timeout, sc);
1309                 break;
1310         }
1311 }
1312
1313 static void
1314 carp_multicast_cleanup(struct carp_softc *sc)
1315 {
1316         struct ip_moptions *imo = &sc->sc_imo;
1317
1318         if (imo->imo_num_memberships == 0)
1319                 return;
1320         KKASSERT(imo->imo_num_memberships == 1);
1321
1322         in_delmulti(imo->imo_membership[0]);
1323         imo->imo_membership[0] = NULL;
1324         imo->imo_num_memberships = 0;
1325         imo->imo_multicast_ifp = NULL;
1326 }
1327
1328 #ifdef INET6
1329 static void
1330 carp_multicast6_cleanup(struct carp_softc *sc)
1331 {
1332         struct ip6_moptions *im6o = &sc->sc_im6o;
1333
1334         while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1335                 struct in6_multi_mship *imm =
1336                     LIST_FIRST(&im6o->im6o_memberships);
1337
1338                 LIST_REMOVE(imm, i6mm_chain);
1339                 in6_leavegroup(imm);
1340         }
1341         im6o->im6o_multicast_ifp = NULL;
1342 }
1343 #endif
1344
1345 static int
1346 carp_get_vhaddr(struct carp_softc *sc, struct ifdrv *ifd)
1347 {
1348         const struct carp_vhaddr *vha;
1349         struct ifcarpvhaddr *carpa, *carpa0;
1350         int count, len, error;
1351
1352         count = 0;
1353         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link)
1354                 ++count;
1355
1356         if (ifd->ifd_len == 0) {
1357                 ifd->ifd_len = count * sizeof(*carpa);
1358                 return 0;
1359         } else if (count == 0 || ifd->ifd_len < sizeof(*carpa)) {
1360                 ifd->ifd_len = 0;
1361                 return 0;
1362         }
1363         len = min(ifd->ifd_len, sizeof(*carpa) * count);
1364         KKASSERT(len >= sizeof(*carpa));
1365
1366         carpa0 = carpa = kmalloc(len, M_TEMP, M_WAITOK | M_NULLOK | M_ZERO);
1367         if (carpa == NULL)
1368                 return ENOMEM;
1369
1370         count = 0;
1371         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
1372                 if (len < sizeof(*carpa))
1373                         break;
1374
1375                 carpa->carpa_flags = vha->vha_flags;
1376                 carpa->carpa_addr.sin_family = AF_INET;
1377                 carpa->carpa_addr.sin_addr = vha->vha_ia->ia_addr.sin_addr;
1378
1379                 carpa->carpa_baddr.sin_family = AF_INET;
1380                 if (vha->vha_iaback == NULL) {
1381                         carpa->carpa_baddr.sin_addr.s_addr = INADDR_ANY;
1382                 } else {
1383                         carpa->carpa_baddr.sin_addr =
1384                         vha->vha_iaback->ia_addr.sin_addr;
1385                 }
1386
1387                 ++carpa;
1388                 ++count;
1389                 len -= sizeof(*carpa);
1390         }
1391         ifd->ifd_len = sizeof(*carpa) * count;
1392         KKASSERT(ifd->ifd_len > 0);
1393
1394         error = copyout(carpa0, ifd->ifd_data, ifd->ifd_len);
1395         kfree(carpa0, M_TEMP);
1396         return error;
1397 }
1398
1399 static int
1400 carp_config_vhaddr(struct carp_softc *sc, struct carp_vhaddr *vha)
1401 {
1402         struct ifnet *ifp;
1403         struct in_ifaddr *ia_if;
1404         struct in_ifaddr_container *iac;
1405         const struct sockaddr_in *sin;
1406         u_long iaddr;
1407         int own;
1408
1409         KKASSERT(vha->vha_ia != NULL);
1410
1411         sin = &vha->vha_ia->ia_addr;
1412         iaddr = ntohl(sin->sin_addr.s_addr);
1413
1414         ia_if = NULL;
1415         own = 0;
1416         TAILQ_FOREACH(iac, &in_ifaddrheads[mycpuid], ia_link) {
1417                 struct in_ifaddr *ia = iac->ia;
1418
1419                 if ((ia->ia_flags & IFA_ROUTE) == 0)
1420                         continue;
1421
1422                 if (ia->ia_ifp->if_type == IFT_CARP)
1423                         continue;
1424
1425                 /* and, yeah, we need a multicast-capable iface too */
1426                 if ((ia->ia_ifp->if_flags & IFF_MULTICAST) == 0)
1427                         continue;
1428
1429                 if ((iaddr & ia->ia_subnetmask) == ia->ia_subnet) {
1430                         if (sin->sin_addr.s_addr ==
1431                             ia->ia_addr.sin_addr.s_addr)
1432                                 own = 1;
1433                         if (ia_if == NULL)
1434                                 ia_if = ia;
1435                         else if (sc->sc_carpdev != NULL &&
1436                                  sc->sc_carpdev == ia->ia_ifp)
1437                                 ia_if = ia;
1438                 }
1439         }
1440
1441         carp_deactivate_vhaddr(sc, vha);
1442         if (!ia_if)
1443                 return ENOENT;
1444
1445         ifp = ia_if->ia_ifp;
1446
1447         /* XXX Don't allow parent iface to be changed */
1448         if (sc->sc_carpdev != NULL && sc->sc_carpdev != ifp)
1449                 return EEXIST;
1450
1451         return carp_activate_vhaddr(sc, vha, ifp, ia_if, own);
1452 }
1453
1454 static void
1455 carp_add_addr(struct carp_softc *sc, struct ifaddr *carp_ifa)
1456 {
1457         struct carp_vhaddr *vha_new;
1458         struct in_ifaddr *carp_ia;
1459 #ifdef INVARIANTS
1460         struct carp_vhaddr *vha;
1461 #endif
1462
1463         KKASSERT(carp_ifa->ifa_addr->sa_family == AF_INET);
1464         carp_ia = ifatoia(carp_ifa);
1465
1466 #ifdef INVARIANTS
1467         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link)
1468                 KKASSERT(vha->vha_ia != NULL && vha->vha_ia != carp_ia);
1469 #endif
1470
1471         vha_new = kmalloc(sizeof(*vha_new), M_CARP, M_WAITOK | M_ZERO);
1472         vha_new->vha_ia = carp_ia;
1473         carp_insert_vhaddr(sc, vha_new);
1474
1475         if (carp_config_vhaddr(sc, vha_new) != 0) {
1476                 /*
1477                  * If the above configuration fails, it may only mean
1478                  * that the new address is problematic.  However, the
1479                  * carp(4) interface may already have several working
1480                  * addresses.  Since the expected behaviour of
1481                  * SIOC[AS]IFADDR is to put the NIC into working state,
1482                  * we try starting the state machine manually here with
1483                  * the hope that the carp(4)'s previously working
1484                  * addresses still could be brought up.
1485                  */
1486                 carp_hmac_prepare(sc);
1487                 carp_set_state(sc, INIT);
1488                 carp_setrun(sc, 0);
1489         }
1490 }
1491
1492 static void
1493 carp_del_addr(struct carp_softc *sc, struct ifaddr *carp_ifa)
1494 {
1495         struct carp_vhaddr *vha;
1496         struct in_ifaddr *carp_ia;
1497
1498         KKASSERT(carp_ifa->ifa_addr->sa_family == AF_INET);
1499         carp_ia = ifatoia(carp_ifa);
1500
1501         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
1502                 KKASSERT(vha->vha_ia != NULL);
1503                 if (vha->vha_ia == carp_ia)
1504                         break;
1505         }
1506         KASSERT(vha != NULL, ("no corresponding vhaddr %p\n", carp_ifa));
1507
1508         /*
1509          * Remove the vhaddr from the list before deactivating
1510          * the vhaddr, so that the HMAC could be correctly
1511          * updated in carp_deactivate_vhaddr()
1512          */
1513         carp_remove_vhaddr(sc, vha);
1514
1515         carp_deactivate_vhaddr(sc, vha);
1516         kfree(vha, M_CARP);
1517 }
1518
1519 static void
1520 carp_config_addr(struct carp_softc *sc, struct ifaddr *carp_ifa)
1521 {
1522         struct carp_vhaddr *vha;
1523         struct in_ifaddr *carp_ia;
1524
1525         KKASSERT(carp_ifa->ifa_addr->sa_family == AF_INET);
1526         carp_ia = ifatoia(carp_ifa);
1527
1528         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
1529                 KKASSERT(vha->vha_ia != NULL);
1530                 if (vha->vha_ia == carp_ia)
1531                         break;
1532         }
1533         KASSERT(vha != NULL, ("no corresponding vhaddr %p\n", carp_ifa));
1534
1535         /* Remove then reinsert, to keep the vhaddr list sorted */
1536         carp_remove_vhaddr(sc, vha);
1537         carp_insert_vhaddr(sc, vha);
1538
1539         if (carp_config_vhaddr(sc, vha) != 0) {
1540                 /* See the comment in carp_add_addr() */
1541                 carp_hmac_prepare(sc);
1542                 carp_set_state(sc, INIT);
1543                 carp_setrun(sc, 0);
1544         }
1545 }
1546
1547 #ifdef INET6
1548 static int
1549 carp_set_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1550 {
1551         struct ifnet *ifp;
1552         struct carp_if *cif;
1553         struct in6_ifaddr *ia, *ia_if;
1554         struct ip6_moptions *im6o = &sc->sc_im6o;
1555         struct in6_multi_mship *imm;
1556         struct in6_addr in6;
1557         int own, error;
1558
1559         if (IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
1560                 carp_setrun(sc, 0);
1561                 return (0);
1562         }
1563
1564         /* we have to do it by hands to check we won't match on us */
1565         ia_if = NULL; own = 0;
1566         for (ia = in6_ifaddr; ia; ia = ia->ia_next) {
1567                 int i;
1568
1569                 for (i = 0; i < 4; i++) {
1570                         if ((sin6->sin6_addr.s6_addr32[i] &
1571                             ia->ia_prefixmask.sin6_addr.s6_addr32[i]) !=
1572                             (ia->ia_addr.sin6_addr.s6_addr32[i] &
1573                             ia->ia_prefixmask.sin6_addr.s6_addr32[i]))
1574                                 break;
1575                 }
1576                 /* and, yeah, we need a multicast-capable iface too */
1577                 if (ia->ia_ifp != &sc->sc_if &&
1578                     (ia->ia_ifp->if_flags & IFF_MULTICAST) &&
1579                     (i == 4)) {
1580                         if (!ia_if)
1581                                 ia_if = ia;
1582                         if (IN6_ARE_ADDR_EQUAL(&sin6->sin6_addr,
1583                             &ia->ia_addr.sin6_addr))
1584                                 own++;
1585                 }
1586         }
1587
1588         if (!ia_if)
1589                 return (EADDRNOTAVAIL);
1590         ia = ia_if;
1591         ifp = ia->ia_ifp;
1592
1593         if (ifp == NULL || (ifp->if_flags & IFF_MULTICAST) == 0 ||
1594             (im6o->im6o_multicast_ifp && im6o->im6o_multicast_ifp != ifp))
1595                 return (EADDRNOTAVAIL);
1596
1597         if (!sc->sc_naddrs6) {
1598                 im6o->im6o_multicast_ifp = ifp;
1599
1600                 /* join CARP multicast address */
1601                 bzero(&in6, sizeof(in6));
1602                 in6.s6_addr16[0] = htons(0xff02);
1603                 in6.s6_addr8[15] = 0x12;
1604                 if (in6_setscope(&in6, ifp, NULL) != 0)
1605                         goto cleanup;
1606                 if ((imm = in6_joingroup(ifp, &in6, &error)) == NULL)
1607                         goto cleanup;
1608                 LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
1609
1610                 /* join solicited multicast address */
1611                 bzero(&in6, sizeof(in6));
1612                 in6.s6_addr16[0] = htons(0xff02);
1613                 in6.s6_addr32[1] = 0;
1614                 in6.s6_addr32[2] = htonl(1);
1615                 in6.s6_addr32[3] = sin6->sin6_addr.s6_addr32[3];
1616                 in6.s6_addr8[12] = 0xff;
1617                 if (in6_setscope(&in6, ifp, NULL) != 0)
1618                         goto cleanup;
1619                 if ((imm = in6_joingroup(ifp, &in6, &error)) == NULL)
1620                         goto cleanup;
1621                 LIST_INSERT_HEAD(&im6o->im6o_memberships, imm, i6mm_chain);
1622         }
1623
1624         if (!ifp->if_carp) {
1625                 cif = kmalloc(sizeof(*cif), M_CARP, M_WAITOK | M_ZERO);
1626
1627                 if ((error = ifpromisc(ifp, 1))) {
1628                         kfree(cif, M_CARP);
1629                         goto cleanup;
1630                 }
1631
1632                 TAILQ_INIT(&cif->vhif_vrs);
1633                 ifp->if_carp = cif;
1634         } else {
1635                 struct carp_softc *vr;
1636
1637                 cif = ifp->if_carp;
1638                 TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1639                         if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
1640                                 error = EINVAL;
1641                                 goto cleanup;
1642                         }
1643                 }
1644         }
1645         sc->sc_ia6 = ia;
1646         sc->sc_carpdev = ifp;
1647
1648         { /* XXX prevent endless loop if already in queue */
1649         struct carp_softc *vr, *after = NULL;
1650         int myself = 0;
1651         cif = ifp->if_carp;
1652
1653         TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1654                 if (vr == sc)
1655                         myself = 1;
1656                 if (vr->sc_vhid < sc->sc_vhid)
1657                         after = vr;
1658         }
1659
1660         if (!myself) {
1661                 /* We're trying to keep things in order */
1662                 if (after == NULL)
1663                         TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
1664                 else
1665                         TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
1666         }
1667         }
1668
1669         sc->sc_naddrs6++;
1670         if (own)
1671                 sc->sc_advskew = 0;
1672         carp_sc_state(sc);
1673         carp_setrun(sc, 0);
1674
1675         return (0);
1676
1677 cleanup:
1678         /* clean up multicast memberships */
1679         if (!sc->sc_naddrs6) {
1680                 while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1681                         imm = LIST_FIRST(&im6o->im6o_memberships);
1682                         LIST_REMOVE(imm, i6mm_chain);
1683                         in6_leavegroup(imm);
1684                 }
1685         }
1686         return (error);
1687 }
1688
1689 static int
1690 carp_del_addr6(struct carp_softc *sc, struct sockaddr_in6 *sin6)
1691 {
1692         int error = 0;
1693
1694         if (!--sc->sc_naddrs6) {
1695                 struct carp_if *cif = sc->sc_carpdev->if_carp;
1696                 struct ip6_moptions *im6o = &sc->sc_im6o;
1697
1698                 callout_stop(&sc->sc_ad_tmo);
1699                 sc->sc_vhid = -1;
1700                 while (!LIST_EMPTY(&im6o->im6o_memberships)) {
1701                         struct in6_multi_mship *imm =
1702                             LIST_FIRST(&im6o->im6o_memberships);
1703
1704                         LIST_REMOVE(imm, i6mm_chain);
1705                         in6_leavegroup(imm);
1706                 }
1707                 im6o->im6o_multicast_ifp = NULL;
1708                 TAILQ_REMOVE(&cif->vhif_vrs, sc, sc_list);
1709                 if (TAILQ_EMPTY(&cif->vhif_vrs)) {
1710                         sc->sc_carpdev->if_carp = NULL;
1711                         kfree(cif, M_IFADDR);
1712                 }
1713         }
1714         return (error);
1715 }
1716 #endif /* INET6 */
1717
1718 static int
1719 carp_ioctl(struct ifnet *ifp, u_long cmd, caddr_t addr, struct ucred *cr)
1720 {
1721         struct carp_softc *sc = ifp->if_softc, *vr;
1722         struct carpreq carpr;
1723         struct ifaddr *ifa;
1724         struct ifreq *ifr;
1725         struct ifaliasreq *ifra;
1726         struct ifdrv *ifd;
1727         char devname[IFNAMSIZ];
1728         int error = 0;
1729
1730         ifa = (struct ifaddr *)addr;
1731         ifra = (struct ifaliasreq *)addr;
1732         ifr = (struct ifreq *)addr;
1733         ifd = (struct ifdrv *)addr;
1734
1735         switch (cmd) {
1736         case SIOCSIFADDR:
1737                 switch (ifa->ifa_addr->sa_family) {
1738 #ifdef INET
1739                 case AF_INET:
1740                         ifp->if_flags |= IFF_UP | IFF_RUNNING;
1741                         break;
1742 #endif /* INET */
1743 #ifdef INET6
1744                 case AF_INET6:
1745                         ifp->if_flags |= IFF_UP | IFF_RUNNING;
1746                         error = carp_set_addr6(sc, satosin6(ifa->ifa_addr));
1747                         break;
1748 #endif /* INET6 */
1749                 default:
1750                         error = EAFNOSUPPORT;
1751                         break;
1752                 }
1753                 break;
1754
1755         case SIOCAIFADDR:
1756                 switch (ifa->ifa_addr->sa_family) {
1757 #ifdef INET
1758                 case AF_INET:
1759                         panic("SIOCAIFADDR should never be seen\n");
1760 #endif /* INET */
1761 #ifdef INET6
1762                 case AF_INET6:
1763                         ifp->if_flags |= IFF_UP | IFF_RUNNING;
1764                         error = carp_set_addr6(sc, satosin6(&ifra->ifra_addr));
1765                         break;
1766 #endif /* INET6 */
1767                 default:
1768                         error = EAFNOSUPPORT;
1769                         break;
1770                 }
1771                 break;
1772
1773         case SIOCDIFADDR:
1774                 switch (ifa->ifa_addr->sa_family) {
1775 #ifdef INET
1776                 case AF_INET:
1777                         panic("SIOCDIFADDR should never be seen\n");
1778 #endif /* INET */
1779 #ifdef INET6
1780                 case AF_INET6:
1781                         error = carp_del_addr6(sc, satosin6(&ifra->ifra_addr));
1782                         break;
1783 #endif /* INET6 */
1784                 default:
1785                         error = EAFNOSUPPORT;
1786                         break;
1787                 }
1788                 break;
1789
1790         case SIOCSIFFLAGS:
1791                 if (ifp->if_flags & IFF_UP) {
1792                         if ((ifp->if_flags & IFF_RUNNING) == 0) {
1793                                 ifp->if_flags |= IFF_RUNNING;
1794                                 carp_set_state(sc, INIT);
1795                                 carp_setrun(sc, 0);
1796                         }
1797                 } else if (ifp->if_flags & IFF_RUNNING) {
1798                         carp_stop(sc, 0);
1799                 }
1800                 break;
1801
1802         case SIOCSVH:
1803                 error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY);
1804                 if (error)
1805                         break;
1806                 error = copyin(ifr->ifr_data, &carpr, sizeof(carpr));
1807                 if (error)
1808                         break;
1809
1810                 error = 1;
1811                 if ((ifp->if_flags & IFF_RUNNING) &&
1812                     sc->sc_state != INIT && carpr.carpr_state != sc->sc_state) {
1813                         switch (carpr.carpr_state) {
1814                         case BACKUP:
1815                                 callout_stop(&sc->sc_ad_tmo);
1816                                 carp_set_state(sc, BACKUP);
1817                                 carp_setrun(sc, 0);
1818                                 carp_setroute(sc, RTM_DELETE);
1819                                 break;
1820
1821                         case MASTER:
1822                                 carp_master_down(sc);
1823                                 break;
1824
1825                         default:
1826                                 break;
1827                         }
1828                 }
1829                 if (carpr.carpr_vhid > 0) {
1830                         if (carpr.carpr_vhid > 255) {
1831                                 error = EINVAL;
1832                                 break;
1833                         }
1834                         if (sc->sc_carpdev) {
1835                                 struct carp_if *cif = sc->sc_carpdev->if_carp;
1836
1837                                 TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
1838                                         if (vr != sc &&
1839                                             vr->sc_vhid == carpr.carpr_vhid)
1840                                                 return EEXIST;
1841                                 }
1842                         }
1843                         sc->sc_vhid = carpr.carpr_vhid;
1844                         IF_LLADDR(ifp)[0] = 0;
1845                         IF_LLADDR(ifp)[1] = 0;
1846                         IF_LLADDR(ifp)[2] = 0x5e;
1847                         IF_LLADDR(ifp)[3] = 0;
1848                         IF_LLADDR(ifp)[4] = 1;
1849                         IF_LLADDR(ifp)[5] = sc->sc_vhid;
1850                         error--;
1851                 }
1852                 if (carpr.carpr_advbase > 0 || carpr.carpr_advskew > 0) {
1853                         if (carpr.carpr_advskew >= 255) {
1854                                 error = EINVAL;
1855                                 break;
1856                         }
1857                         if (carpr.carpr_advbase > 255) {
1858                                 error = EINVAL;
1859                                 break;
1860                         }
1861                         sc->sc_advbase = carpr.carpr_advbase;
1862                         sc->sc_advskew = carpr.carpr_advskew;
1863                         error--;
1864                 }
1865                 bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1866                 if (error > 0) {
1867                         error = EINVAL;
1868                 } else {
1869                         error = 0;
1870                         carp_setrun(sc, 0);
1871                 }
1872                 break;
1873
1874         case SIOCGVH:
1875                 bzero(&carpr, sizeof(carpr));
1876                 carpr.carpr_state = sc->sc_state;
1877                 carpr.carpr_vhid = sc->sc_vhid;
1878                 carpr.carpr_advbase = sc->sc_advbase;
1879                 carpr.carpr_advskew = sc->sc_advskew;
1880                 error = priv_check_cred(cr, PRIV_ROOT, NULL_CRED_OKAY);
1881                 if (error == 0) {
1882                         bcopy(sc->sc_key, carpr.carpr_key,
1883                               sizeof(carpr.carpr_key));
1884                 }
1885
1886                 error = copyout(&carpr, ifr->ifr_data, sizeof(carpr));
1887                 break;
1888
1889         case SIOCGDRVSPEC:
1890                 switch (ifd->ifd_cmd) {
1891                 case CARPGDEVNAME:
1892                         if (ifd->ifd_len != sizeof(devname))
1893                                 error = EINVAL;
1894                         break;
1895
1896                 case CARPGVHADDR:
1897                         break;
1898
1899                 default:
1900                         error = EINVAL;
1901                         break;
1902                 }
1903                 if (error)
1904                         break;
1905
1906                 switch (ifd->ifd_cmd) {
1907                 case CARPGVHADDR:
1908                         error = carp_get_vhaddr(sc, ifd);
1909                         break;
1910
1911                 case CARPGDEVNAME:
1912                         bzero(devname, sizeof(devname));
1913                         if (sc->sc_carpdev != NULL) {
1914                                 strlcpy(devname, sc->sc_carpdev->if_xname,
1915                                         sizeof(devname));
1916                         }
1917                         error = copyout(devname, ifd->ifd_data,
1918                                         sizeof(devname));
1919                         break;
1920                 }
1921                 break;
1922
1923         default:
1924                 error = EINVAL;
1925                 break;
1926         }
1927         carp_hmac_prepare(sc);
1928         return error;
1929 }
1930
1931 /*
1932  * XXX: this is looutput. We should eventually use it from there.
1933  */
1934 static int
1935 carp_looutput(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
1936     struct rtentry *rt)
1937 {
1938         uint32_t af;
1939
1940         M_ASSERTPKTHDR(m); /* check if we have the packet header */
1941
1942         if (rt && rt->rt_flags & (RTF_REJECT|RTF_BLACKHOLE)) {
1943                 m_freem(m);
1944                 return (rt->rt_flags & RTF_BLACKHOLE ? 0 :
1945                         rt->rt_flags & RTF_HOST ? EHOSTUNREACH : ENETUNREACH);
1946         }
1947
1948         ifp->if_opackets++;
1949         ifp->if_obytes += m->m_pkthdr.len;
1950
1951         /* BPF writes need to be handled specially. */
1952         if (dst->sa_family == AF_UNSPEC) {
1953                 bcopy(dst->sa_data, &af, sizeof(af));
1954                 dst->sa_family = af;
1955         }
1956
1957 #if 1   /* XXX */
1958         switch (dst->sa_family) {
1959         case AF_INET:
1960         case AF_INET6:
1961         case AF_IPX:
1962                 break;
1963
1964         default:
1965                 m_freem(m);
1966                 return (EAFNOSUPPORT);
1967         }
1968 #endif
1969         return (if_simloop(ifp, m, dst->sa_family, 0));
1970 }
1971
1972 /*
1973  * Start output on carp interface. This function should never be called.
1974  */
1975 static void
1976 carp_start(struct ifnet *ifp)
1977 {
1978 #ifdef DEBUG
1979         kprintf("%s: start called\n", ifp->if_xname);
1980 #endif
1981 }
1982
1983 int
1984 carp_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *sa,
1985     struct rtentry *rt)
1986 {
1987         struct m_tag *mtag;
1988         struct carp_softc *sc;
1989         struct ifnet *carp_ifp;
1990         struct ether_header *eh;
1991
1992         if (!sa)
1993                 return (0);
1994
1995         switch (sa->sa_family) {
1996 #ifdef INET
1997         case AF_INET:
1998                 break;
1999 #endif /* INET */
2000 #ifdef INET6
2001         case AF_INET6:
2002                 break;
2003 #endif /* INET6 */
2004         default:
2005                 return (0);
2006         }
2007
2008         mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
2009         if (mtag == NULL)
2010                 return (0);
2011
2012         bcopy(mtag + 1, &carp_ifp, sizeof(struct ifnet *));
2013         sc = carp_ifp->if_softc;
2014
2015         /* Set the source MAC address to Virtual Router MAC Address */
2016         switch (ifp->if_type) {
2017         case IFT_ETHER:
2018         case IFT_L2VLAN:
2019                 eh = mtod(m, struct ether_header *);
2020                 eh->ether_shost[0] = 0;
2021                 eh->ether_shost[1] = 0;
2022                 eh->ether_shost[2] = 0x5e;
2023                 eh->ether_shost[3] = 0;
2024                 eh->ether_shost[4] = 1;
2025                 eh->ether_shost[5] = sc->sc_vhid;
2026                 break;
2027
2028         default:
2029                 if_printf(ifp, "carp is not supported for this "
2030                           "interface type\n");
2031                 return (EOPNOTSUPP);
2032         }
2033         return (0);
2034 }
2035
2036 static void
2037 carp_set_state(struct carp_softc *sc, int state)
2038 {
2039         struct ifnet *cifp = &sc->sc_if;
2040
2041         if (sc->sc_state == state)
2042                 return;
2043         sc->sc_state = state;
2044
2045         switch (sc->sc_state) {
2046         case BACKUP:
2047                 cifp->if_link_state = LINK_STATE_DOWN;
2048                 break;
2049
2050         case MASTER:
2051                 cifp->if_link_state = LINK_STATE_UP;
2052                 break;
2053
2054         default:
2055                 cifp->if_link_state = LINK_STATE_UNKNOWN;
2056                 break;
2057         }
2058         rt_ifmsg(cifp);
2059 }
2060
2061 void
2062 carp_group_demote_adj(struct ifnet *ifp, int adj)
2063 {
2064         struct ifg_list *ifgl;
2065         int *dm;
2066
2067         TAILQ_FOREACH(ifgl, &ifp->if_groups, ifgl_next) {
2068                 if (!strcmp(ifgl->ifgl_group->ifg_group, IFG_ALL))
2069                         continue;
2070                 dm = &ifgl->ifgl_group->ifg_carp_demoted;
2071
2072                 if (*dm + adj >= 0)
2073                         *dm += adj;
2074                 else
2075                         *dm = 0;
2076
2077                 if (adj > 0 && *dm == 1)
2078                         carp_send_ad_all();
2079                 CARP_LOG("%s demoted group %s to %d", ifp->if_xname,
2080                     ifgl->ifgl_group->ifg_group, *dm);
2081         }
2082 }
2083
2084 void
2085 carp_carpdev_state(void *v)
2086 {
2087         struct carp_if *cif = v;
2088         struct carp_softc *sc;
2089
2090         TAILQ_FOREACH(sc, &cif->vhif_vrs, sc_list)
2091                 carp_sc_state(sc);
2092 }
2093
2094 static void
2095 carp_sc_state(struct carp_softc *sc)
2096 {
2097         if (!(sc->sc_carpdev->if_flags & IFF_UP)) {
2098                 callout_stop(&sc->sc_ad_tmo);
2099                 callout_stop(&sc->sc_md_tmo);
2100                 callout_stop(&sc->sc_md6_tmo);
2101                 carp_set_state(sc, INIT);
2102                 carp_setrun(sc, 0);
2103                 if (!sc->sc_suppress) {
2104                         carp_suppress_preempt++;
2105                         if (carp_suppress_preempt == 1)
2106                                 carp_send_ad_all();
2107                 }
2108                 sc->sc_suppress = 1;
2109         } else {
2110                 carp_set_state(sc, INIT);
2111                 carp_setrun(sc, 0);
2112                 if (sc->sc_suppress)
2113                         carp_suppress_preempt--;
2114                 sc->sc_suppress = 0;
2115         }
2116 }
2117
2118 static void
2119 carp_stop(struct carp_softc *sc, int detach)
2120 {
2121         sc->sc_if.if_flags &= ~IFF_RUNNING;
2122
2123         callout_stop(&sc->sc_ad_tmo);
2124         callout_stop(&sc->sc_md_tmo);
2125         callout_stop(&sc->sc_md6_tmo);
2126
2127         if (!detach && sc->sc_state == MASTER)
2128                 carp_send_ad(sc);
2129
2130         if (sc->sc_suppress)
2131                 carp_suppress_preempt--;
2132         sc->sc_suppress = 0;
2133
2134         if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS)
2135                 carp_suppress_preempt--;
2136         sc->sc_sendad_errors = 0;
2137         sc->sc_sendad_success = 0;
2138
2139         carp_set_state(sc, INIT);
2140         carp_setrun(sc, 0);
2141 }
2142
2143 static void
2144 carp_reset(struct carp_softc *sc, int detach)
2145 {
2146         struct ifnet *cifp = &sc->sc_if;
2147
2148         carp_stop(sc, detach);
2149         if (!sc->sc_dead && (cifp->if_flags & IFF_UP))
2150                 cifp->if_flags |= IFF_RUNNING;
2151 }
2152
2153 static int
2154 carp_activate_vhaddr(struct carp_softc *sc, struct carp_vhaddr *vha,
2155                      struct ifnet *ifp, const struct in_ifaddr *ia_if, int own)
2156 {
2157         struct ip_moptions *imo = &sc->sc_imo;
2158         struct carp_if *cif;
2159         struct carp_softc *vr, *after = NULL;
2160         int onlist, error;
2161 #ifdef INVARIANTS
2162         int assert_onlist;
2163 #endif
2164
2165         KKASSERT(vha->vha_ia != NULL);
2166
2167         KASSERT(ia_if != NULL, ("NULL backing address\n"));
2168         KASSERT(vha->vha_iaback == NULL, ("%p is already activated\n", vha));
2169         KASSERT((vha->vha_flags & CARP_VHAF_OWNER) == 0,
2170                 ("inactive vhaddr %p is the address owner\n", vha));
2171
2172         KASSERT(sc->sc_carpdev == NULL || sc->sc_carpdev == ifp,
2173                 ("%s is already on %s\n", sc->sc_if.if_xname,
2174                  sc->sc_carpdev->if_xname));
2175
2176         KASSERT(imo->imo_multicast_ifp == NULL ||
2177                 imo->imo_multicast_ifp == ifp,
2178                 ("%s didn't leave mcast group on %s\n",
2179                  sc->sc_if.if_xname, imo->imo_multicast_ifp->if_xname));
2180
2181         if (imo->imo_num_memberships == 0) {
2182                 struct in_addr addr;
2183
2184                 addr.s_addr = htonl(INADDR_CARP_GROUP);
2185                 if ((imo->imo_membership[0] = in_addmulti(&addr, ifp)) == NULL)
2186                         return ENOBUFS;
2187                 imo->imo_num_memberships++;
2188                 imo->imo_multicast_ifp = ifp;
2189                 imo->imo_multicast_ttl = CARP_DFLTTL;
2190                 imo->imo_multicast_loop = 0;
2191         }
2192
2193         if (!ifp->if_carp) {
2194                 KASSERT(sc->sc_carpdev == NULL,
2195                         ("%s is already on %s\n", sc->sc_if.if_xname,
2196                          sc->sc_carpdev->if_xname));
2197
2198                 cif = kmalloc(sizeof(*cif), M_CARP, M_WAITOK | M_ZERO);
2199
2200                 error = ifpromisc(ifp, 1);
2201                 if (error) {
2202                         kfree(cif, M_CARP);
2203                         goto cleanup;
2204                 }
2205
2206                 TAILQ_INIT(&cif->vhif_vrs);
2207                 ifp->if_carp = cif;
2208         } else {
2209                 cif = ifp->if_carp;
2210                 TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
2211                         if (vr != sc && vr->sc_vhid == sc->sc_vhid) {
2212                                 error = EINVAL;
2213                                 goto cleanup;
2214                         }
2215                 }
2216         }
2217
2218 #ifdef INVARIANTS
2219         if (sc->sc_carpdev != NULL)
2220                 assert_onlist = 1;
2221         else
2222                 assert_onlist = 0;
2223 #endif
2224         sc->sc_ia = ia_if;
2225         sc->sc_carpdev = ifp;
2226
2227         cif = ifp->if_carp;
2228         onlist = 0;
2229         TAILQ_FOREACH(vr, &cif->vhif_vrs, sc_list) {
2230                 if (vr == sc)
2231                         onlist = 1;
2232                 if (vr->sc_vhid < sc->sc_vhid)
2233                         after = vr;
2234         }
2235
2236 #ifdef INVARIANTS
2237         if (assert_onlist) {
2238                 KASSERT(onlist, ("%s is not on %s carp list\n",
2239                         sc->sc_if.if_xname, ifp->if_xname));
2240         } else {
2241                 KASSERT(!onlist, ("%s is already on %s carp list\n",
2242                         sc->sc_if.if_xname, ifp->if_xname));
2243         }
2244 #endif
2245
2246         if (!onlist) {
2247                 /* We're trying to keep things in order */
2248                 if (after == NULL)
2249                         TAILQ_INSERT_TAIL(&cif->vhif_vrs, sc, sc_list);
2250                 else
2251                         TAILQ_INSERT_AFTER(&cif->vhif_vrs, after, sc, sc_list);
2252         }
2253
2254         vha->vha_iaback = ia_if;
2255         sc->sc_naddrs++;
2256
2257         if (own) {
2258                 vha->vha_flags |= CARP_VHAF_OWNER;
2259
2260                 /* XXX save user configured advskew? */
2261                 sc->sc_advskew = 0;
2262         }
2263
2264         carp_hmac_prepare(sc);
2265         carp_set_state(sc, INIT);
2266         carp_setrun(sc, 0);
2267         return 0;
2268 cleanup:
2269         carp_multicast_cleanup(sc);
2270         return error;
2271 }
2272
2273 static void
2274 carp_deactivate_vhaddr(struct carp_softc *sc, struct carp_vhaddr *vha)
2275 {
2276         KKASSERT(vha->vha_ia != NULL);
2277
2278         carp_hmac_prepare(sc);
2279
2280         if (vha->vha_iaback == NULL) {
2281                 KASSERT((vha->vha_flags & CARP_VHAF_OWNER) == 0,
2282                         ("inactive vhaddr %p is the address owner\n", vha));
2283                 return;
2284         }
2285
2286         vha->vha_flags &= ~CARP_VHAF_OWNER;
2287
2288         KKASSERT(sc->sc_naddrs > 0);
2289         vha->vha_iaback = NULL;
2290         sc->sc_naddrs--;
2291         if (!sc->sc_naddrs) {
2292                 if (sc->sc_naddrs6) {
2293                         carp_multicast_cleanup(sc);
2294                         sc->sc_ia = NULL;
2295                 } else {
2296                         carp_detach(sc, 0);
2297                 }
2298         }
2299 }
2300
2301 static void
2302 carp_link_addrs(struct carp_softc *sc, struct ifnet *ifp, struct ifaddr *ifa_if)
2303 {
2304         struct carp_vhaddr *vha;
2305         struct in_ifaddr *ia_if;
2306
2307         KKASSERT(ifa_if->ifa_addr->sa_family == AF_INET);
2308         ia_if = ifatoia(ifa_if);
2309
2310         if ((ia_if->ia_flags & IFA_ROUTE) == 0)
2311                 return;
2312
2313         /*
2314          * Test each inactive vhaddr against the newly added address.
2315          * If the newly added address could be the backing address,
2316          * then activate the matching vhaddr.
2317          */
2318         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
2319                 const struct in_ifaddr *ia;
2320                 u_long iaddr;
2321                 int own;
2322
2323                 if (vha->vha_iaback != NULL)
2324                         continue;
2325
2326                 ia = vha->vha_ia;
2327                 iaddr = ntohl(ia->ia_addr.sin_addr.s_addr);
2328
2329                 if ((iaddr & ia_if->ia_subnetmask) != ia_if->ia_subnet)
2330                         continue;
2331
2332                 own = 0;
2333                 if (ia->ia_addr.sin_addr.s_addr ==
2334                     ia_if->ia_addr.sin_addr.s_addr)
2335                         own = 1;
2336
2337                 carp_activate_vhaddr(sc, vha, ifp, ia_if, own);
2338         }
2339 }
2340
2341 static void
2342 carp_unlink_addrs(struct carp_softc *sc, struct ifnet *ifp,
2343                   struct ifaddr *ifa_if)
2344 {
2345         struct carp_vhaddr *vha;
2346         struct in_ifaddr *ia_if;
2347
2348         KKASSERT(ifa_if->ifa_addr->sa_family == AF_INET);
2349         ia_if = ifatoia(ifa_if);
2350
2351         /*
2352          * Ad src address is deleted; set it to NULL.
2353          * Following loop will try pick up a new ad src address
2354          * if one of the vhaddr could retain its backing address.
2355          */
2356         if (sc->sc_ia == ia_if)
2357                 sc->sc_ia = NULL;
2358
2359         /*
2360          * Test each active vhaddr against the deleted address.
2361          * If the deleted address is vhaddr address's backing
2362          * address, then deactivate the vhaddr.
2363          */
2364         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link) {
2365                 if (vha->vha_iaback == NULL)
2366                         continue;
2367
2368                 if (vha->vha_iaback == ia_if)
2369                         carp_deactivate_vhaddr(sc, vha);
2370                 else if (sc->sc_ia == NULL)
2371                         sc->sc_ia = vha->vha_iaback;
2372         }
2373 }
2374
2375 static void
2376 carp_update_addrs(struct carp_softc *sc)
2377 {
2378         struct carp_vhaddr *vha;
2379
2380         KKASSERT(sc->sc_carpdev == NULL);
2381
2382         TAILQ_FOREACH(vha, &sc->sc_vha_list, vha_link)
2383                 carp_config_vhaddr(sc, vha);
2384 }
2385
2386 static void
2387 carp_ifaddr(void *arg __unused, struct ifnet *ifp,
2388             enum ifaddr_event event, struct ifaddr *ifa)
2389 {
2390         struct carp_softc *sc;
2391
2392         if (ifa->ifa_addr->sa_family != AF_INET)
2393                 return;
2394
2395         if (ifp->if_type == IFT_CARP) {
2396                 /*
2397                  * Address is changed on carp(4) interface
2398                  */
2399                 switch (event) {
2400                 case IFADDR_EVENT_ADD:
2401                         carp_add_addr(ifp->if_softc, ifa);
2402                         break;
2403
2404                 case IFADDR_EVENT_CHANGE:
2405                         carp_config_addr(ifp->if_softc, ifa);
2406                         break;
2407
2408                 case IFADDR_EVENT_DELETE:
2409                         carp_del_addr(ifp->if_softc, ifa);
2410                         break;
2411                 }
2412                 return;
2413         }
2414
2415         /*
2416          * Address is changed on non-carp(4) interface
2417          */
2418         if ((ifp->if_flags & IFF_MULTICAST) == 0)
2419                 return;
2420
2421         crit_enter();
2422         LIST_FOREACH(sc, &carpif_list, sc_next) {
2423                 if (sc->sc_carpdev != NULL && sc->sc_carpdev != ifp) {
2424                         /* Not the parent iface; skip */
2425                         continue;
2426                 }
2427
2428                 switch (event) {
2429                 case IFADDR_EVENT_ADD:
2430                         carp_link_addrs(sc, ifp, ifa);
2431                         break;
2432
2433                 case IFADDR_EVENT_DELETE:
2434                         if (sc->sc_carpdev != NULL) {
2435                                 carp_unlink_addrs(sc, ifp, ifa);
2436                                 if (sc->sc_carpdev == NULL)
2437                                         carp_update_addrs(sc);
2438                         } else {
2439                                 /*
2440                                  * The carp(4) interface didn't have a
2441                                  * parent iface, so it is not possible
2442                                  * that it will contain any address to
2443                                  * be unlinked.
2444                                  */
2445                         }
2446                         break;
2447
2448                 case IFADDR_EVENT_CHANGE:
2449                         if (sc->sc_carpdev == NULL) {
2450                                 /*
2451                                  * The carp(4) interface didn't have a
2452                                  * parent iface, so it is not possible
2453                                  * that it will contain any address to
2454                                  * be updated.
2455                                  */
2456                                 carp_link_addrs(sc, ifp, ifa);
2457                         } else {
2458                                 /*
2459                                  * First try breaking tie with the old
2460                                  * address.  Then see whether we could
2461                                  * link certain vhaddr to the new address.
2462                                  * If that fails, i.e. carpdev is NULL,
2463                                  * we try a global update.
2464                                  *
2465                                  * NOTE: The above order is critical.
2466                                  */
2467                                 carp_unlink_addrs(sc, ifp, ifa);
2468                                 carp_link_addrs(sc, ifp, ifa);
2469                                 if (sc->sc_carpdev == NULL)
2470                                         carp_update_addrs(sc);
2471                         }
2472                         break;
2473                 }
2474         }
2475         crit_exit();
2476 }
2477
2478 static int
2479 carp_modevent(module_t mod, int type, void *data)
2480 {
2481         switch (type) {
2482         case MOD_LOAD:
2483                 LIST_INIT(&carpif_list);
2484                 carp_ifdetach_event =
2485                 EVENTHANDLER_REGISTER(ifnet_detach_event, carp_ifdetach, NULL,
2486                                       EVENTHANDLER_PRI_ANY);
2487                 carp_ifaddr_event =
2488                 EVENTHANDLER_REGISTER(ifaddr_event, carp_ifaddr, NULL,
2489                                       EVENTHANDLER_PRI_ANY);
2490                 if_clone_attach(&carp_cloner);
2491                 break;
2492
2493         case MOD_UNLOAD:
2494                 EVENTHANDLER_DEREGISTER(ifnet_detach_event,
2495                                         carp_ifdetach_event);
2496                 EVENTHANDLER_DEREGISTER(ifaddr_event,
2497                                         carp_ifaddr_event);
2498                 if_clone_detach(&carp_cloner);
2499                 break;
2500
2501         default:
2502                 return (EINVAL);
2503         }
2504         return (0);
2505 }
2506
2507 static moduledata_t carp_mod = {
2508         "carp",
2509         carp_modevent,
2510         0
2511 };
2512 DECLARE_MODULE(carp, carp_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);