sys/netinet/ip_carp.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2002 Michael Shalayeff.
   5  * Copyright (c) 2003 Ryan McBride.
   6  * Copyright (c) 2011 Gleb Smirnoff <glebius@FreeBSD.org>
   7  * All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  19  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  20  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  21  * IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
  22  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  23  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  24  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  26  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  27  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  28  * THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #include <sys/cdefs.h>
  32 __FBSDID("$FreeBSD$");
  33
  34 #include "opt_bpf.h"
  35 #include "opt_inet.h"
  36 #include "opt_inet6.h"
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/devctl.h>
  41 #include <sys/jail.h>
  42 #include <sys/kernel.h>
  43 #include <sys/limits.h>
  44 #include <sys/malloc.h>
  45 #include <sys/mbuf.h>
  46 #include <sys/module.h>
  47 #include <sys/priv.h>
  48 #include <sys/proc.h>
  49 #include <sys/socket.h>
  50 #include <sys/sockio.h>
  51 #include <sys/sysctl.h>
  52 #include <sys/syslog.h>
  53 #include <sys/taskqueue.h>
  54 #include <sys/counter.h>
  55
  56 #include <net/ethernet.h>
  57 #include <net/if.h>
  58 #include <net/if_var.h>
  59 #include <net/if_dl.h>
  60 #include <net/if_llatbl.h>
  61 #include <net/if_types.h>
  62 #include <net/route.h>
  63 #include <net/vnet.h>
  64
  65 #if defined(INET) || defined(INET6)
  66 #include <netinet/in.h>
  67 #include <netinet/in_var.h>
  68 #include <netinet/ip_carp.h>
  69 #include <netinet/ip.h>
  70 #include <machine/in_cksum.h>
  71 #endif
  72 #ifdef INET
  73 #include <netinet/ip_var.h>
  74 #include <netinet/if_ether.h>
  75 #endif
  76
  77 #ifdef INET6
  78 #include <netinet/icmp6.h>
  79 #include <netinet/ip6.h>
  80 #include <netinet6/in6_var.h>
  81 #include <netinet6/ip6_var.h>
  82 #include <netinet6/scope6_var.h>
  83 #include <netinet6/nd6.h>
  84 #endif
  85
  86 #include <crypto/sha1.h>
  87
  88 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
  89
  90 struct carp_softc {
  91         struct ifnet            *sc_carpdev;    /* Pointer to parent ifnet. */
  92         struct ifaddr           **sc_ifas;      /* Our ifaddrs. */
  93         struct sockaddr_dl      sc_addr;        /* Our link level address. */
  94         struct callout          sc_ad_tmo;      /* Advertising timeout. */
  95 #ifdef INET
  96         struct callout          sc_md_tmo;      /* Master down timeout. */
  97 #endif
  98 #ifdef INET6
  99         struct callout          sc_md6_tmo;     /* XXX: Master down timeout. */
 100 #endif
 101         struct mtx              sc_mtx;
 102
 103         int                     sc_vhid;
 104         int                     sc_advskew;
 105         int                     sc_advbase;
 106
 107         int                     sc_naddrs;
 108         int                     sc_naddrs6;
 109         int                     sc_ifasiz;
 110         enum { INIT = 0, BACKUP, MASTER }       sc_state;
 111         int                     sc_suppress;
 112         int                     sc_sendad_errors;
 113 #define CARP_SENDAD_MAX_ERRORS  3
 114         int                     sc_sendad_success;
 115 #define CARP_SENDAD_MIN_SUCCESS 3
 116
 117         int                     sc_init_counter;
 118         uint64_t                sc_counter;
 119
 120         /* authentication */
 121 #define CARP_HMAC_PAD   64
 122         unsigned char sc_key[CARP_KEY_LEN];
 123         unsigned char sc_pad[CARP_HMAC_PAD];
 124         SHA1_CTX sc_sha1;
 125
 126         TAILQ_ENTRY(carp_softc) sc_list;        /* On the carp_if list. */
 127         LIST_ENTRY(carp_softc)  sc_next;        /* On the global list. */
 128 };
 129
 130 struct carp_if {
 131 #ifdef INET
 132         int     cif_naddrs;
 133 #endif
 134 #ifdef INET6
 135         int     cif_naddrs6;
 136 #endif
 137         TAILQ_HEAD(, carp_softc) cif_vrs;
 138 #ifdef INET
 139         struct ip_moptions       cif_imo;
 140 #endif
 141 #ifdef INET6
 142         struct ip6_moptions      cif_im6o;
 143 #endif
 144         struct ifnet    *cif_ifp;
 145         struct mtx      cif_mtx;
 146         uint32_t        cif_flags;
 147 #define CIF_PROMISC     0x00000001
 148 };
 149
 150 /*
 151  * Brief design of carp(4).
 152  *
 153  * Any carp-capable ifnet may have a list of carp softcs hanging off
 154  * its ifp->if_carp pointer. Each softc represents one unique virtual
 155  * host id, or vhid. The softc has a back pointer to the ifnet. All
 156  * softcs are joined in a global list, which has quite limited use.
 157  *
 158  * Any interface address that takes part in CARP negotiation has a
 159  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
 160  * AF_INET or AF_INET6 address.
 161  *
 162  * Although, one can get the softc's backpointer to ifnet and traverse
 163  * through its ifp->if_addrhead queue to find all interface addresses
 164  * involved in CARP, we keep a growable array of ifaddr pointers. This
 165  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
 166  * do calls into the network stack, thus avoiding LORs.
 167  *
 168  * Locking:
 169  *
 170  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
 171  * callout-driven events and ioctl()s.
 172  *
 173  * To traverse the list of softcs on an ifnet we use CIF_LOCK() or carp_sx.
 174  * To traverse the global list we use the mutex carp_mtx.
 175  *
 176  * Known issues with locking:
 177  *
 178  * - Sending ad, we put the pointer to the softc in an mtag, and no reference
 179  *   counting is done on the softc.
 180  * - On module unload we may race (?) with packet processing thread
 181  *   dereferencing our function pointers.
 182  */
 183
 184 /* Accept incoming CARP packets. */
 185 VNET_DEFINE_STATIC(int, carp_allow) = 1;
 186 #define V_carp_allow    VNET(carp_allow)
 187
 188 /* Set DSCP in outgoing CARP packets. */
 189 VNET_DEFINE_STATIC(int, carp_dscp) = 56;
 190 #define V_carp_dscp     VNET(carp_dscp)
 191
 192 /* Preempt slower nodes. */
 193 VNET_DEFINE_STATIC(int, carp_preempt) = 0;
 194 #define V_carp_preempt  VNET(carp_preempt)
 195
 196 /* Log level. */
 197 VNET_DEFINE_STATIC(int, carp_log) = 1;
 198 #define V_carp_log      VNET(carp_log)
 199
 200 /* Global advskew demotion. */
 201 VNET_DEFINE_STATIC(int, carp_demotion) = 0;
 202 #define V_carp_demotion VNET(carp_demotion)
 203
 204 /* Send error demotion factor. */
 205 VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
 206 #define V_carp_senderr_adj      VNET(carp_senderr_adj)
 207
 208 /* Iface down demotion factor. */
 209 VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
 210 #define V_carp_ifdown_adj       VNET(carp_ifdown_adj)
 211
 212 static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
 213 static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
 214 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
 215
 216 SYSCTL_NODE(_net_inet, IPPROTO_CARP, carp, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 217     "CARP");
 218 SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
 219     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 220     0, 0, carp_allow_sysctl, "I",
 221     "Accept incoming CARP packets");
 222 SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
 223     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 224     0, 0, carp_dscp_sysctl, "I",
 225     "DSCP value for carp packets");
 226 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
 227     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
 228 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
 229     &VNET_NAME(carp_log), 0, "CARP log level");
 230 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
 231     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 232     0, 0, carp_demote_adj_sysctl, "I",
 233     "Adjust demotion factor (skew of advskew)");
 234 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
 235     CTLFLAG_VNET | CTLFLAG_RW,
 236     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
 237 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
 238     CTLFLAG_VNET | CTLFLAG_RW,
 239     &VNET_NAME(carp_ifdown_adj), 0,
 240     "Interface down demotion factor adjustment");
 241
 242 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
 243 VNET_PCPUSTAT_SYSINIT(carpstats);
 244 VNET_PCPUSTAT_SYSUNINIT(carpstats);
 245
 246 #define CARPSTATS_ADD(name, val)        \
 247     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
 248         sizeof(uint64_t)], (val))
 249 #define CARPSTATS_INC(name)             CARPSTATS_ADD(name, 1)
 250
 251 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
 252     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
 253
 254 #define CARP_LOCK_INIT(sc)      mtx_init(&(sc)->sc_mtx, "carp_softc",   \
 255         NULL, MTX_DEF)
 256 #define CARP_LOCK_DESTROY(sc)   mtx_destroy(&(sc)->sc_mtx)
 257 #define CARP_LOCK_ASSERT(sc)    mtx_assert(&(sc)->sc_mtx, MA_OWNED)
 258 #define CARP_LOCK(sc)           mtx_lock(&(sc)->sc_mtx)
 259 #define CARP_UNLOCK(sc)         mtx_unlock(&(sc)->sc_mtx)
 260 #define CIF_LOCK_INIT(cif)      mtx_init(&(cif)->cif_mtx, "carp_if",   \
 261         NULL, MTX_DEF)
 262 #define CIF_LOCK_DESTROY(cif)   mtx_destroy(&(cif)->cif_mtx)
 263 #define CIF_LOCK_ASSERT(cif)    mtx_assert(&(cif)->cif_mtx, MA_OWNED)
 264 #define CIF_LOCK(cif)           mtx_lock(&(cif)->cif_mtx)
 265 #define CIF_UNLOCK(cif)         mtx_unlock(&(cif)->cif_mtx)
 266 #define CIF_FREE(cif)   do {                            \
 267                 CIF_LOCK(cif);                          \
 268                 if (TAILQ_EMPTY(&(cif)->cif_vrs))       \
 269                         carp_free_if(cif);              \
 270                 else                                    \
 271                         CIF_UNLOCK(cif);                \
 272 } while (0)
 273
 274 #define CARP_LOG(...)   do {                            \
 275         if (V_carp_log > 0)                             \
 276                 log(LOG_INFO, "carp: " __VA_ARGS__);    \
 277 } while (0)
 278
 279 #define CARP_DEBUG(...) do {                            \
 280         if (V_carp_log > 1)                             \
 281                 log(LOG_DEBUG, __VA_ARGS__);            \
 282 } while (0)
 283
 284 #define IFNET_FOREACH_IFA(ifp, ifa)                                     \
 285         CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link) \
 286                 if ((ifa)->ifa_carp != NULL)
 287
 288 #define CARP_FOREACH_IFA(sc, ifa)                                       \
 289         CARP_LOCK_ASSERT(sc);                                           \
 290         for (int _i = 0;                                                \
 291                 _i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&              \
 292                 ((ifa) = sc->sc_ifas[_i]) != NULL;                      \
 293                 ++_i)
 294
 295 #define IFNET_FOREACH_CARP(ifp, sc)                                     \
 296         KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) ||                    \
 297             sx_xlocked(&carp_sx), ("cif_vrs not locked"));              \
 298         TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
 299
 300 #define DEMOTE_ADVSKEW(sc)                                      \
 301     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?      \
 302     CARP_MAXSKEW :                                              \
 303         (((sc)->sc_advskew + V_carp_demotion < 0) ?             \
 304         0 : ((sc)->sc_advskew + V_carp_demotion)))
 305
 306 static void     carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
 307 static struct carp_softc
 308                 *carp_alloc(struct ifnet *);
 309 static void     carp_destroy(struct carp_softc *);
 310 static struct carp_if
 311                 *carp_alloc_if(struct ifnet *);
 312 static void     carp_free_if(struct carp_if *);
 313 static void     carp_set_state(struct carp_softc *, int, const char* reason);
 314 static void     carp_sc_state(struct carp_softc *);
 315 static void     carp_setrun(struct carp_softc *, sa_family_t);
 316 static void     carp_master_down(void *);
 317 static void     carp_master_down_locked(struct carp_softc *,
 318                     const char* reason);
 319 static void     carp_send_ad(void *);
 320 static void     carp_send_ad_locked(struct carp_softc *);
 321 static void     carp_addroute(struct carp_softc *);
 322 static void     carp_ifa_addroute(struct ifaddr *);
 323 static void     carp_delroute(struct carp_softc *);
 324 static void     carp_ifa_delroute(struct ifaddr *);
 325 static void     carp_send_ad_all(void *, int);
 326 static void     carp_demote_adj(int, char *);
 327
 328 static LIST_HEAD(, carp_softc) carp_list;
 329 static struct mtx carp_mtx;
 330 static struct sx carp_sx;
 331 static struct task carp_sendall_task =
 332     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
 333
 334 static void
 335 carp_hmac_prepare(struct carp_softc *sc)
 336 {
 337         uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
 338         uint8_t vhid = sc->sc_vhid & 0xff;
 339         struct ifaddr *ifa;
 340         int i, found;
 341 #ifdef INET
 342         struct in_addr last, cur, in;
 343 #endif
 344 #ifdef INET6
 345         struct in6_addr last6, cur6, in6;
 346 #endif
 347
 348         CARP_LOCK_ASSERT(sc);
 349
 350         /* Compute ipad from key. */
 351         bzero(sc->sc_pad, sizeof(sc->sc_pad));
 352         bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
 353         for (i = 0; i < sizeof(sc->sc_pad); i++)
 354                 sc->sc_pad[i] ^= 0x36;
 355
 356         /* Precompute first part of inner hash. */
 357         SHA1Init(&sc->sc_sha1);
 358         SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
 359         SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
 360         SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
 361         SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
 362 #ifdef INET
 363         cur.s_addr = 0;
 364         do {
 365                 found = 0;
 366                 last = cur;
 367                 cur.s_addr = 0xffffffff;
 368                 CARP_FOREACH_IFA(sc, ifa) {
 369                         in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
 370                         if (ifa->ifa_addr->sa_family == AF_INET &&
 371                             ntohl(in.s_addr) > ntohl(last.s_addr) &&
 372                             ntohl(in.s_addr) < ntohl(cur.s_addr)) {
 373                                 cur.s_addr = in.s_addr;
 374                                 found++;
 375                         }
 376                 }
 377                 if (found)
 378                         SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
 379         } while (found);
 380 #endif /* INET */
 381 #ifdef INET6
 382         memset(&cur6, 0, sizeof(cur6));
 383         do {
 384                 found = 0;
 385                 last6 = cur6;
 386                 memset(&cur6, 0xff, sizeof(cur6));
 387                 CARP_FOREACH_IFA(sc, ifa) {
 388                         in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
 389                         if (IN6_IS_SCOPE_EMBED(&in6))
 390                                 in6.s6_addr16[1] = 0;
 391                         if (ifa->ifa_addr->sa_family == AF_INET6 &&
 392                             memcmp(&in6, &last6, sizeof(in6)) > 0 &&
 393                             memcmp(&in6, &cur6, sizeof(in6)) < 0) {
 394                                 cur6 = in6;
 395                                 found++;
 396                         }
 397                 }
 398                 if (found)
 399                         SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
 400         } while (found);
 401 #endif /* INET6 */
 402
 403         /* convert ipad to opad */
 404         for (i = 0; i < sizeof(sc->sc_pad); i++)
 405                 sc->sc_pad[i] ^= 0x36 ^ 0x5c;
 406 }
 407
 408 static void
 409 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
 410     unsigned char md[20])
 411 {
 412         SHA1_CTX sha1ctx;
 413
 414         CARP_LOCK_ASSERT(sc);
 415
 416         /* fetch first half of inner hash */
 417         bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
 418
 419         SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
 420         SHA1Final(md, &sha1ctx);
 421
 422         /* outer hash */
 423         SHA1Init(&sha1ctx);
 424         SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
 425         SHA1Update(&sha1ctx, md, 20);
 426         SHA1Final(md, &sha1ctx);
 427 }
 428
 429 static int
 430 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
 431     unsigned char md[20])
 432 {
 433         unsigned char md2[20];
 434
 435         CARP_LOCK_ASSERT(sc);
 436
 437         carp_hmac_generate(sc, counter, md2);
 438
 439         return (bcmp(md, md2, sizeof(md2)));
 440 }
 441
 442 /*
 443  * process input packet.
 444  * we have rearranged checks order compared to the rfc,
 445  * but it seems more efficient this way or not possible otherwise.
 446  */
 447 #ifdef INET
 448 static int
 449 carp_input(struct mbuf **mp, int *offp, int proto)
 450 {
 451         struct mbuf *m = *mp;
 452         struct ip *ip = mtod(m, struct ip *);
 453         struct carp_header *ch;
 454         int iplen, len;
 455
 456         iplen = *offp;
 457         *mp = NULL;
 458
 459         CARPSTATS_INC(carps_ipackets);
 460
 461         if (!V_carp_allow) {
 462                 m_freem(m);
 463                 return (IPPROTO_DONE);
 464         }
 465
 466         /* verify that the IP TTL is 255.  */
 467         if (ip->ip_ttl != CARP_DFLTTL) {
 468                 CARPSTATS_INC(carps_badttl);
 469                 CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
 470                     ip->ip_ttl,
 471                     m->m_pkthdr.rcvif->if_xname);
 472                 m_freem(m);
 473                 return (IPPROTO_DONE);
 474         }
 475
 476         iplen = ip->ip_hl << 2;
 477
 478         if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
 479                 CARPSTATS_INC(carps_badlen);
 480                 CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
 481                     "on %s\n", __func__, m->m_len - sizeof(struct ip),
 482                     m->m_pkthdr.rcvif->if_xname);
 483                 m_freem(m);
 484                 return (IPPROTO_DONE);
 485         }
 486
 487         if (iplen + sizeof(*ch) < m->m_len) {
 488                 if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
 489                         CARPSTATS_INC(carps_hdrops);
 490                         CARP_DEBUG("%s: pullup failed\n", __func__);
 491                         return (IPPROTO_DONE);
 492                 }
 493                 ip = mtod(m, struct ip *);
 494         }
 495         ch = (struct carp_header *)((char *)ip + iplen);
 496
 497         /*
 498          * verify that the received packet length is
 499          * equal to the CARP header
 500          */
 501         len = iplen + sizeof(*ch);
 502         if (len > m->m_pkthdr.len) {
 503                 CARPSTATS_INC(carps_badlen);
 504                 CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
 505                     m->m_pkthdr.len,
 506                     m->m_pkthdr.rcvif->if_xname);
 507                 m_freem(m);
 508                 return (IPPROTO_DONE);
 509         }
 510
 511         if ((m = m_pullup(m, len)) == NULL) {
 512                 CARPSTATS_INC(carps_hdrops);
 513                 return (IPPROTO_DONE);
 514         }
 515         ip = mtod(m, struct ip *);
 516         ch = (struct carp_header *)((char *)ip + iplen);
 517
 518         /* verify the CARP checksum */
 519         m->m_data += iplen;
 520         if (in_cksum(m, len - iplen)) {
 521                 CARPSTATS_INC(carps_badsum);
 522                 CARP_DEBUG("%s: checksum failed on %s\n", __func__,
 523                     m->m_pkthdr.rcvif->if_xname);
 524                 m_freem(m);
 525                 return (IPPROTO_DONE);
 526         }
 527         m->m_data -= iplen;
 528
 529         carp_input_c(m, ch, AF_INET);
 530         return (IPPROTO_DONE);
 531 }
 532 #endif
 533
 534 #ifdef INET6
 535 static int
 536 carp6_input(struct mbuf **mp, int *offp, int proto)
 537 {
 538         struct mbuf *m = *mp;
 539         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 540         struct carp_header *ch;
 541         u_int len;
 542
 543         CARPSTATS_INC(carps_ipackets6);
 544
 545         if (!V_carp_allow) {
 546                 m_freem(m);
 547                 return (IPPROTO_DONE);
 548         }
 549
 550         /* check if received on a valid carp interface */
 551         if (m->m_pkthdr.rcvif->if_carp == NULL) {
 552                 CARPSTATS_INC(carps_badif);
 553                 CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
 554                     __func__, m->m_pkthdr.rcvif->if_xname);
 555                 m_freem(m);
 556                 return (IPPROTO_DONE);
 557         }
 558
 559         /* verify that the IP TTL is 255 */
 560         if (ip6->ip6_hlim != CARP_DFLTTL) {
 561                 CARPSTATS_INC(carps_badttl);
 562                 CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
 563                     ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
 564                 m_freem(m);
 565                 return (IPPROTO_DONE);
 566         }
 567
 568         /* verify that we have a complete carp packet */
 569         if (m->m_len < *offp + sizeof(*ch)) {
 570                 len = m->m_len;
 571                 m = m_pullup(m, *offp + sizeof(*ch));
 572                 if (m == NULL) {
 573                         CARPSTATS_INC(carps_badlen);
 574                         CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
 575                         return (IPPROTO_DONE);
 576                 }
 577         }
 578         ch = (struct carp_header *)(mtod(m, char *) + *offp);
 579
 580         /* verify the CARP checksum */
 581         m->m_data += *offp;
 582         if (in_cksum(m, sizeof(*ch))) {
 583                 CARPSTATS_INC(carps_badsum);
 584                 CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
 585                     m->m_pkthdr.rcvif->if_xname);
 586                 m_freem(m);
 587                 return (IPPROTO_DONE);
 588         }
 589         m->m_data -= *offp;
 590
 591         carp_input_c(m, ch, AF_INET6);
 592         return (IPPROTO_DONE);
 593 }
 594 #endif /* INET6 */
 595
 596 /*
 597  * This routine should not be necessary at all, but some switches
 598  * (VMWare ESX vswitches) can echo our own packets back at us,
 599  * and we must ignore them or they will cause us to drop out of
 600  * MASTER mode.
 601  *
 602  * We cannot catch all cases of network loops.  Instead, what we
 603  * do here is catch any packet that arrives with a carp header
 604  * with a VHID of 0, that comes from an address that is our own.
 605  * These packets are by definition "from us" (even if they are from
 606  * a misconfigured host that is pretending to be us).
 607  *
 608  * The VHID test is outside this mini-function.
 609  */
 610 static int
 611 carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
 612 {
 613 #ifdef INET
 614         struct ip *ip4;
 615         struct in_addr in4;
 616 #endif
 617 #ifdef INET6
 618         struct ip6_hdr *ip6;
 619         struct in6_addr in6;
 620 #endif
 621
 622         switch (af) {
 623 #ifdef INET
 624         case AF_INET:
 625                 ip4 = mtod(m, struct ip *);
 626                 in4 = ifatoia(ifa)->ia_addr.sin_addr;
 627                 return (in4.s_addr == ip4->ip_src.s_addr);
 628 #endif
 629 #ifdef INET6
 630         case AF_INET6:
 631                 ip6 = mtod(m, struct ip6_hdr *);
 632                 in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
 633                 return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
 634 #endif
 635         default:
 636                 break;
 637         }
 638         return (0);
 639 }
 640
 641 static void
 642 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
 643 {
 644         struct ifnet *ifp = m->m_pkthdr.rcvif;
 645         struct ifaddr *ifa, *match;
 646         struct carp_softc *sc;
 647         uint64_t tmp_counter;
 648         struct timeval sc_tv, ch_tv;
 649         int error;
 650
 651         NET_EPOCH_ASSERT();
 652
 653         /*
 654          * Verify that the VHID is valid on the receiving interface.
 655          *
 656          * There should be just one match.  If there are none
 657          * the VHID is not valid and we drop the packet.  If
 658          * there are multiple VHID matches, take just the first
 659          * one, for compatibility with previous code.  While we're
 660          * scanning, check for obvious loops in the network topology
 661          * (these should never happen, and as noted above, we may
 662          * miss real loops; this is just a double-check).
 663          */
 664         error = 0;
 665         match = NULL;
 666         IFNET_FOREACH_IFA(ifp, ifa) {
 667                 if (match == NULL && ifa->ifa_carp != NULL &&
 668                     ifa->ifa_addr->sa_family == af &&
 669                     ifa->ifa_carp->sc_vhid == ch->carp_vhid)
 670                         match = ifa;
 671                 if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
 672                         error = ELOOP;
 673         }
 674         ifa = error ? NULL : match;
 675         if (ifa != NULL)
 676                 ifa_ref(ifa);
 677
 678         if (ifa == NULL) {
 679                 if (error == ELOOP) {
 680                         CARP_DEBUG("dropping looped packet on interface %s\n",
 681                             ifp->if_xname);
 682                         CARPSTATS_INC(carps_badif);     /* ??? */
 683                 } else {
 684                         CARPSTATS_INC(carps_badvhid);
 685                 }
 686                 m_freem(m);
 687                 return;
 688         }
 689
 690         /* verify the CARP version. */
 691         if (ch->carp_version != CARP_VERSION) {
 692                 CARPSTATS_INC(carps_badver);
 693                 CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
 694                     ch->carp_version);
 695                 ifa_free(ifa);
 696                 m_freem(m);
 697                 return;
 698         }
 699
 700         sc = ifa->ifa_carp;
 701         CARP_LOCK(sc);
 702         ifa_free(ifa);
 703
 704         if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
 705                 CARPSTATS_INC(carps_badauth);
 706                 CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
 707                     sc->sc_vhid, ifp->if_xname);
 708                 goto out;
 709         }
 710
 711         tmp_counter = ntohl(ch->carp_counter[0]);
 712         tmp_counter = tmp_counter<<32;
 713         tmp_counter += ntohl(ch->carp_counter[1]);
 714
 715         /* XXX Replay protection goes here */
 716
 717         sc->sc_init_counter = 0;
 718         sc->sc_counter = tmp_counter;
 719
 720         sc_tv.tv_sec = sc->sc_advbase;
 721         sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
 722         ch_tv.tv_sec = ch->carp_advbase;
 723         ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
 724
 725         switch (sc->sc_state) {
 726         case INIT:
 727                 break;
 728         case MASTER:
 729                 /*
 730                  * If we receive an advertisement from a master who's going to
 731                  * be more frequent than us, go into BACKUP state.
 732                  */
 733                 if (timevalcmp(&sc_tv, &ch_tv, >) ||
 734                     timevalcmp(&sc_tv, &ch_tv, ==)) {
 735                         callout_stop(&sc->sc_ad_tmo);
 736                         carp_set_state(sc, BACKUP,
 737                             "more frequent advertisement received");
 738                         carp_setrun(sc, 0);
 739                         carp_delroute(sc);
 740                 }
 741                 break;
 742         case BACKUP:
 743                 /*
 744                  * If we're pre-empting masters who advertise slower than us,
 745                  * and this one claims to be slower, treat him as down.
 746                  */
 747                 if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
 748                         carp_master_down_locked(sc,
 749                             "preempting a slower master");
 750                         break;
 751                 }
 752
 753                 /*
 754                  *  If the master is going to advertise at such a low frequency
 755                  *  that he's guaranteed to time out, we'd might as well just
 756                  *  treat him as timed out now.
 757                  */
 758                 sc_tv.tv_sec = sc->sc_advbase * 3;
 759                 if (timevalcmp(&sc_tv, &ch_tv, <)) {
 760                         carp_master_down_locked(sc, "master will time out");
 761                         break;
 762                 }
 763
 764                 /*
 765                  * Otherwise, we reset the counter and wait for the next
 766                  * advertisement.
 767                  */
 768                 carp_setrun(sc, af);
 769                 break;
 770         }
 771
 772 out:
 773         CARP_UNLOCK(sc);
 774         m_freem(m);
 775 }
 776
 777 static int
 778 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
 779 {
 780         struct m_tag *mtag;
 781
 782         if (sc->sc_init_counter) {
 783                 /* this could also be seconds since unix epoch */
 784                 sc->sc_counter = arc4random();
 785                 sc->sc_counter = sc->sc_counter << 32;
 786                 sc->sc_counter += arc4random();
 787         } else
 788                 sc->sc_counter++;
 789
 790         ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
 791         ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
 792
 793         carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
 794
 795         /* Tag packet for carp_output */
 796         if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
 797             M_NOWAIT)) == NULL) {
 798                 m_freem(m);
 799                 CARPSTATS_INC(carps_onomem);
 800                 return (ENOMEM);
 801         }
 802         bcopy(&sc, mtag + 1, sizeof(sc));
 803         m_tag_prepend(m, mtag);
 804
 805         return (0);
 806 }
 807
 808 /*
 809  * To avoid LORs and possible recursions this function shouldn't
 810  * be called directly, but scheduled via taskqueue.
 811  */
 812 static void
 813 carp_send_ad_all(void *ctx __unused, int pending __unused)
 814 {
 815         struct carp_softc *sc;
 816         struct epoch_tracker et;
 817
 818         NET_EPOCH_ENTER(et);
 819         mtx_lock(&carp_mtx);
 820         LIST_FOREACH(sc, &carp_list, sc_next)
 821                 if (sc->sc_state == MASTER) {
 822                         CARP_LOCK(sc);
 823                         CURVNET_SET(sc->sc_carpdev->if_vnet);
 824                         carp_send_ad_locked(sc);
 825                         CURVNET_RESTORE();
 826                         CARP_UNLOCK(sc);
 827                 }
 828         mtx_unlock(&carp_mtx);
 829         NET_EPOCH_EXIT(et);
 830 }
 831
 832 /* Send a periodic advertisement, executed in callout context. */
 833 static void
 834 carp_send_ad(void *v)
 835 {
 836         struct carp_softc *sc = v;
 837         struct epoch_tracker et;
 838
 839         NET_EPOCH_ENTER(et);
 840         CARP_LOCK_ASSERT(sc);
 841         CURVNET_SET(sc->sc_carpdev->if_vnet);
 842         carp_send_ad_locked(sc);
 843         CURVNET_RESTORE();
 844         CARP_UNLOCK(sc);
 845         NET_EPOCH_EXIT(et);
 846 }
 847
 848 static void
 849 carp_send_ad_error(struct carp_softc *sc, int error)
 850 {
 851
 852         /*
 853          * We track errors and successfull sends with this logic:
 854          * - Any error resets success counter to 0.
 855          * - MAX_ERRORS triggers demotion.
 856          * - MIN_SUCCESS successes resets error counter to 0.
 857          * - MIN_SUCCESS reverts demotion, if it was triggered before.
 858          */
 859         if (error) {
 860                 if (sc->sc_sendad_errors < INT_MAX)
 861                         sc->sc_sendad_errors++;
 862                 if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
 863                         static const char fmt[] = "send error %d on %s";
 864                         char msg[sizeof(fmt) + IFNAMSIZ];
 865
 866                         sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
 867                         carp_demote_adj(V_carp_senderr_adj, msg);
 868                 }
 869                 sc->sc_sendad_success = 0;
 870         } else if (sc->sc_sendad_errors > 0) {
 871                 if (++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
 872                         if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
 873                                 static const char fmt[] = "send ok on %s";
 874                                 char msg[sizeof(fmt) + IFNAMSIZ];
 875
 876                                 sprintf(msg, fmt, sc->sc_carpdev->if_xname);
 877                                 carp_demote_adj(-V_carp_senderr_adj, msg);
 878                         }
 879                         sc->sc_sendad_errors = 0;
 880                 }
 881         }
 882 }
 883
 884 /*
 885  * Pick the best ifaddr on the given ifp for sending CARP
 886  * advertisements.
 887  *
 888  * "Best" here is defined by ifa_preferred().  This function is much
 889  * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
 890  *
 891  * (This could be simplified to return the actual address, except that
 892  * it has a different format in AF_INET and AF_INET6.)
 893  */
 894 static struct ifaddr *
 895 carp_best_ifa(int af, struct ifnet *ifp)
 896 {
 897         struct ifaddr *ifa, *best;
 898
 899         NET_EPOCH_ASSERT();
 900
 901         if (af >= AF_MAX)
 902                 return (NULL);
 903         best = NULL;
 904         CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 905                 if (ifa->ifa_addr->sa_family == af &&
 906                     (best == NULL || ifa_preferred(best, ifa)))
 907                         best = ifa;
 908         }
 909         if (best != NULL)
 910                 ifa_ref(best);
 911         return (best);
 912 }
 913
 914 static void
 915 carp_send_ad_locked(struct carp_softc *sc)
 916 {
 917         struct carp_header ch;
 918         struct timeval tv;
 919         struct ifaddr *ifa;
 920         struct carp_header *ch_ptr;
 921         struct mbuf *m;
 922         int len, advskew;
 923
 924         NET_EPOCH_ASSERT();
 925         CARP_LOCK_ASSERT(sc);
 926
 927         advskew = DEMOTE_ADVSKEW(sc);
 928         tv.tv_sec = sc->sc_advbase;
 929         tv.tv_usec = advskew * 1000000 / 256;
 930
 931         ch.carp_version = CARP_VERSION;
 932         ch.carp_type = CARP_ADVERTISEMENT;
 933         ch.carp_vhid = sc->sc_vhid;
 934         ch.carp_advbase = sc->sc_advbase;
 935         ch.carp_advskew = advskew;
 936         ch.carp_authlen = 7;    /* XXX DEFINE */
 937         ch.carp_pad1 = 0;       /* must be zero */
 938         ch.carp_cksum = 0;
 939
 940         /* XXXGL: OpenBSD picks first ifaddr with needed family. */
 941
 942 #ifdef INET
 943         if (sc->sc_naddrs) {
 944                 struct ip *ip;
 945
 946                 m = m_gethdr(M_NOWAIT, MT_DATA);
 947                 if (m == NULL) {
 948                         CARPSTATS_INC(carps_onomem);
 949                         goto resched;
 950                 }
 951                 len = sizeof(*ip) + sizeof(ch);
 952                 m->m_pkthdr.len = len;
 953                 m->m_pkthdr.rcvif = NULL;
 954                 m->m_len = len;
 955                 M_ALIGN(m, m->m_len);
 956                 m->m_flags |= M_MCAST;
 957                 ip = mtod(m, struct ip *);
 958                 ip->ip_v = IPVERSION;
 959                 ip->ip_hl = sizeof(*ip) >> 2;
 960                 ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
 961                 ip->ip_len = htons(len);
 962                 ip->ip_off = htons(IP_DF);
 963                 ip->ip_ttl = CARP_DFLTTL;
 964                 ip->ip_p = IPPROTO_CARP;
 965                 ip->ip_sum = 0;
 966                 ip_fillid(ip);
 967
 968                 ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
 969                 if (ifa != NULL) {
 970                         ip->ip_src.s_addr =
 971                             ifatoia(ifa)->ia_addr.sin_addr.s_addr;
 972                         ifa_free(ifa);
 973                 } else
 974                         ip->ip_src.s_addr = 0;
 975                 ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
 976
 977                 ch_ptr = (struct carp_header *)(&ip[1]);
 978                 bcopy(&ch, ch_ptr, sizeof(ch));
 979                 if (carp_prepare_ad(m, sc, ch_ptr))
 980                         goto resched;
 981
 982                 m->m_data += sizeof(*ip);
 983                 ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
 984                 m->m_data -= sizeof(*ip);
 985
 986                 CARPSTATS_INC(carps_opackets);
 987
 988                 carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
 989                     &sc->sc_carpdev->if_carp->cif_imo, NULL));
 990         }
 991 #endif /* INET */
 992 #ifdef INET6
 993         if (sc->sc_naddrs6) {
 994                 struct ip6_hdr *ip6;
 995
 996                 m = m_gethdr(M_NOWAIT, MT_DATA);
 997                 if (m == NULL) {
 998                         CARPSTATS_INC(carps_onomem);
 999                         goto resched;
1000                 }
1001                 len = sizeof(*ip6) + sizeof(ch);
1002                 m->m_pkthdr.len = len;
1003                 m->m_pkthdr.rcvif = NULL;
1004                 m->m_len = len;
1005                 M_ALIGN(m, m->m_len);
1006                 m->m_flags |= M_MCAST;
1007                 ip6 = mtod(m, struct ip6_hdr *);
1008                 bzero(ip6, sizeof(*ip6));
1009                 ip6->ip6_vfc |= IPV6_VERSION;
1010                 /* Traffic class isn't defined in ip6 struct instead
1011                  * it gets offset into flowid field */
1012                 ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
1013                     IPTOS_DSCP_OFFSET));
1014                 ip6->ip6_hlim = CARP_DFLTTL;
1015                 ip6->ip6_nxt = IPPROTO_CARP;
1016
1017                 /* set the source address */
1018                 ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1019                 if (ifa != NULL) {
1020                         bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1021                             sizeof(struct in6_addr));
1022                         ifa_free(ifa);
1023                 } else
1024                         /* This should never happen with IPv6. */
1025                         bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1026
1027                 /* Set the multicast destination. */
1028                 ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1029                 ip6->ip6_dst.s6_addr8[15] = 0x12;
1030                 if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1031                         m_freem(m);
1032                         CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1033                         goto resched;
1034                 }
1035
1036                 ch_ptr = (struct carp_header *)(&ip6[1]);
1037                 bcopy(&ch, ch_ptr, sizeof(ch));
1038                 if (carp_prepare_ad(m, sc, ch_ptr))
1039                         goto resched;
1040
1041                 m->m_data += sizeof(*ip6);
1042                 ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1043                 m->m_data -= sizeof(*ip6);
1044
1045                 CARPSTATS_INC(carps_opackets6);
1046
1047                 carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1048                     &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1049         }
1050 #endif /* INET6 */
1051
1052 resched:
1053         callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1054 }
1055
1056 static void
1057 carp_addroute(struct carp_softc *sc)
1058 {
1059         struct ifaddr *ifa;
1060
1061         CARP_FOREACH_IFA(sc, ifa)
1062                 carp_ifa_addroute(ifa);
1063 }
1064
1065 static void
1066 carp_ifa_addroute(struct ifaddr *ifa)
1067 {
1068
1069         switch (ifa->ifa_addr->sa_family) {
1070 #ifdef INET
1071         case AF_INET:
1072                 in_addprefix(ifatoia(ifa));
1073                 ifa_add_loopback_route(ifa,
1074                     (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1075                 break;
1076 #endif
1077 #ifdef INET6
1078         case AF_INET6:
1079                 ifa_add_loopback_route(ifa,
1080                     (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1081                 nd6_add_ifa_lle(ifatoia6(ifa));
1082                 break;
1083 #endif
1084         }
1085 }
1086
1087 static void
1088 carp_delroute(struct carp_softc *sc)
1089 {
1090         struct ifaddr *ifa;
1091
1092         CARP_FOREACH_IFA(sc, ifa)
1093                 carp_ifa_delroute(ifa);
1094 }
1095
1096 static void
1097 carp_ifa_delroute(struct ifaddr *ifa)
1098 {
1099
1100         switch (ifa->ifa_addr->sa_family) {
1101 #ifdef INET
1102         case AF_INET:
1103                 ifa_del_loopback_route(ifa,
1104                     (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1105                 in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1106                 break;
1107 #endif
1108 #ifdef INET6
1109         case AF_INET6:
1110                 ifa_del_loopback_route(ifa,
1111                     (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1112                 nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1113                 break;
1114 #endif
1115         }
1116 }
1117
1118 int
1119 carp_master(struct ifaddr *ifa)
1120 {
1121         struct carp_softc *sc = ifa->ifa_carp;
1122
1123         return (sc->sc_state == MASTER);
1124 }
1125
1126 #ifdef INET
1127 /*
1128  * Broadcast a gratuitous ARP request containing
1129  * the virtual router MAC address for each IP address
1130  * associated with the virtual router.
1131  */
1132 static void
1133 carp_send_arp(struct carp_softc *sc)
1134 {
1135         struct ifaddr *ifa;
1136         struct in_addr addr;
1137
1138         NET_EPOCH_ASSERT();
1139
1140         CARP_FOREACH_IFA(sc, ifa) {
1141                 if (ifa->ifa_addr->sa_family != AF_INET)
1142                         continue;
1143                 addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1144                 arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1145         }
1146 }
1147
1148 int
1149 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1150 {
1151         struct carp_softc *sc = ifa->ifa_carp;
1152
1153         if (sc->sc_state == MASTER) {
1154                 *enaddr = LLADDR(&sc->sc_addr);
1155                 return (1);
1156         }
1157
1158         return (0);
1159 }
1160 #endif
1161
1162 #ifdef INET6
1163 static void
1164 carp_send_na(struct carp_softc *sc)
1165 {
1166         static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1167         struct ifaddr *ifa;
1168         struct in6_addr *in6;
1169
1170         CARP_FOREACH_IFA(sc, ifa) {
1171                 if (ifa->ifa_addr->sa_family != AF_INET6)
1172                         continue;
1173
1174                 in6 = IFA_IN6(ifa);
1175                 nd6_na_output(sc->sc_carpdev, &mcast, in6,
1176                     ND_NA_FLAG_OVERRIDE, 1, NULL);
1177                 DELAY(1000);    /* XXX */
1178         }
1179 }
1180
1181 /*
1182  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1183  * matches and is not a carp address.  Returns NULL otherwise.
1184  */
1185 struct ifaddr *
1186 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1187 {
1188         struct ifaddr *ifa;
1189
1190         NET_EPOCH_ASSERT();
1191
1192         ifa = NULL;
1193         CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1194                 if (ifa->ifa_addr->sa_family != AF_INET6)
1195                         continue;
1196                 if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1197                         continue;
1198                 if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1199                         ifa = NULL;
1200                 else
1201                         ifa_ref(ifa);
1202                 break;
1203         }
1204
1205         return (ifa);
1206 }
1207
1208 char *
1209 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1210 {
1211         struct ifaddr *ifa;
1212
1213         NET_EPOCH_ASSERT();
1214
1215         IFNET_FOREACH_IFA(ifp, ifa)
1216                 if (ifa->ifa_addr->sa_family == AF_INET6 &&
1217                     IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1218                         struct carp_softc *sc = ifa->ifa_carp;
1219                         struct m_tag *mtag;
1220
1221                         mtag = m_tag_get(PACKET_TAG_CARP,
1222                             sizeof(struct carp_softc *), M_NOWAIT);
1223                         if (mtag == NULL)
1224                                 /* Better a bit than nothing. */
1225                                 return (LLADDR(&sc->sc_addr));
1226
1227                         bcopy(&sc, mtag + 1, sizeof(sc));
1228                         m_tag_prepend(m, mtag);
1229
1230                         return (LLADDR(&sc->sc_addr));
1231                 }
1232
1233         return (NULL);
1234 }
1235 #endif /* INET6 */
1236
1237 int
1238 carp_forus(struct ifnet *ifp, u_char *dhost)
1239 {
1240         struct carp_softc *sc;
1241         uint8_t *ena = dhost;
1242
1243         if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1244                 return (0);
1245
1246         CIF_LOCK(ifp->if_carp);
1247         IFNET_FOREACH_CARP(ifp, sc) {
1248                 /*
1249                  * CARP_LOCK() is not here, since would protect nothing, but
1250                  * cause deadlock with if_bridge, calling this under its lock.
1251                  */
1252                 if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1253                     ETHER_ADDR_LEN)) {
1254                         CIF_UNLOCK(ifp->if_carp);
1255                         return (1);
1256                 }
1257         }
1258         CIF_UNLOCK(ifp->if_carp);
1259
1260         return (0);
1261 }
1262
1263 /* Master down timeout event, executed in callout context. */
1264 static void
1265 carp_master_down(void *v)
1266 {
1267         struct carp_softc *sc = v;
1268         struct epoch_tracker et;
1269
1270         NET_EPOCH_ENTER(et);
1271         CARP_LOCK_ASSERT(sc);
1272
1273         CURVNET_SET(sc->sc_carpdev->if_vnet);
1274         if (sc->sc_state == BACKUP) {
1275                 carp_master_down_locked(sc, "master timed out");
1276         }
1277         CURVNET_RESTORE();
1278
1279         CARP_UNLOCK(sc);
1280         NET_EPOCH_EXIT(et);
1281 }
1282
1283 static void
1284 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1285 {
1286
1287         NET_EPOCH_ASSERT();
1288         CARP_LOCK_ASSERT(sc);
1289
1290         switch (sc->sc_state) {
1291         case BACKUP:
1292                 carp_set_state(sc, MASTER, reason);
1293                 carp_send_ad_locked(sc);
1294 #ifdef INET
1295                 carp_send_arp(sc);
1296 #endif
1297 #ifdef INET6
1298                 carp_send_na(sc);
1299 #endif
1300                 carp_setrun(sc, 0);
1301                 carp_addroute(sc);
1302                 break;
1303         case INIT:
1304         case MASTER:
1305 #ifdef INVARIANTS
1306                 panic("carp: VHID %u@%s: master_down event in %s state\n",
1307                     sc->sc_vhid,
1308                     sc->sc_carpdev->if_xname,
1309                     sc->sc_state ? "MASTER" : "INIT");
1310 #endif
1311                 break;
1312         }
1313 }
1314
1315 /*
1316  * When in backup state, af indicates whether to reset the master down timer
1317  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1318  */
1319 static void
1320 carp_setrun(struct carp_softc *sc, sa_family_t af)
1321 {
1322         struct timeval tv;
1323
1324         CARP_LOCK_ASSERT(sc);
1325
1326         if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1327             sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1328             (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1329             !V_carp_allow)
1330                 return;
1331
1332         switch (sc->sc_state) {
1333         case INIT:
1334                 carp_set_state(sc, BACKUP, "initialization complete");
1335                 carp_setrun(sc, 0);
1336                 break;
1337         case BACKUP:
1338                 callout_stop(&sc->sc_ad_tmo);
1339                 tv.tv_sec = 3 * sc->sc_advbase;
1340                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1341                 switch (af) {
1342 #ifdef INET
1343                 case AF_INET:
1344                         callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1345                             carp_master_down, sc);
1346                         break;
1347 #endif
1348 #ifdef INET6
1349                 case AF_INET6:
1350                         callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1351                             carp_master_down, sc);
1352                         break;
1353 #endif
1354                 default:
1355 #ifdef INET
1356                         if (sc->sc_naddrs)
1357                                 callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1358                                     carp_master_down, sc);
1359 #endif
1360 #ifdef INET6
1361                         if (sc->sc_naddrs6)
1362                                 callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1363                                     carp_master_down, sc);
1364 #endif
1365                         break;
1366                 }
1367                 break;
1368         case MASTER:
1369                 tv.tv_sec = sc->sc_advbase;
1370                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1371                 callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1372                     carp_send_ad, sc);
1373                 break;
1374         }
1375 }
1376
1377 /*
1378  * Setup multicast structures.
1379  */
1380 static int
1381 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1382 {
1383         struct ifnet *ifp = cif->cif_ifp;
1384         int error = 0;
1385
1386         switch (sa) {
1387 #ifdef INET
1388         case AF_INET:
1389             {
1390                 struct ip_moptions *imo = &cif->cif_imo;
1391                 struct in_mfilter *imf;
1392                 struct in_addr addr;
1393
1394                 if (ip_mfilter_first(&imo->imo_head) != NULL)
1395                         return (0);
1396
1397                 imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1398                 ip_mfilter_init(&imo->imo_head);
1399                 imo->imo_multicast_vif = -1;
1400
1401                 addr.s_addr = htonl(INADDR_CARP_GROUP);
1402                 if ((error = in_joingroup(ifp, &addr, NULL,
1403                     &imf->imf_inm)) != 0) {
1404                         ip_mfilter_free(imf);
1405                         break;
1406                 }
1407
1408                 ip_mfilter_insert(&imo->imo_head, imf);
1409                 imo->imo_multicast_ifp = ifp;
1410                 imo->imo_multicast_ttl = CARP_DFLTTL;
1411                 imo->imo_multicast_loop = 0;
1412                 break;
1413            }
1414 #endif
1415 #ifdef INET6
1416         case AF_INET6:
1417             {
1418                 struct ip6_moptions *im6o = &cif->cif_im6o;
1419                 struct in6_mfilter *im6f[2];
1420                 struct in6_addr in6;
1421
1422                 if (ip6_mfilter_first(&im6o->im6o_head))
1423                         return (0);
1424
1425                 im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1426                 im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1427
1428                 ip6_mfilter_init(&im6o->im6o_head);
1429                 im6o->im6o_multicast_hlim = CARP_DFLTTL;
1430                 im6o->im6o_multicast_ifp = ifp;
1431
1432                 /* Join IPv6 CARP multicast group. */
1433                 bzero(&in6, sizeof(in6));
1434                 in6.s6_addr16[0] = htons(0xff02);
1435                 in6.s6_addr8[15] = 0x12;
1436                 if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1437                         ip6_mfilter_free(im6f[0]);
1438                         ip6_mfilter_free(im6f[1]);
1439                         break;
1440                 }
1441                 if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1442                         ip6_mfilter_free(im6f[0]);
1443                         ip6_mfilter_free(im6f[1]);
1444                         break;
1445                 }
1446
1447                 /* Join solicited multicast address. */
1448                 bzero(&in6, sizeof(in6));
1449                 in6.s6_addr16[0] = htons(0xff02);
1450                 in6.s6_addr32[1] = 0;
1451                 in6.s6_addr32[2] = htonl(1);
1452                 in6.s6_addr32[3] = 0;
1453                 in6.s6_addr8[12] = 0xff;
1454
1455                 if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1456                         ip6_mfilter_free(im6f[0]);
1457                         ip6_mfilter_free(im6f[1]);
1458                         break;
1459                 }
1460
1461                 if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1462                         in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1463                         ip6_mfilter_free(im6f[0]);
1464                         ip6_mfilter_free(im6f[1]);
1465                         break;
1466                 }
1467                 ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1468                 ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1469                 break;
1470             }
1471 #endif
1472         }
1473
1474         return (error);
1475 }
1476
1477 /*
1478  * Free multicast structures.
1479  */
1480 static void
1481 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1482 {
1483 #ifdef INET
1484         struct ip_moptions *imo = &cif->cif_imo;
1485         struct in_mfilter *imf;
1486 #endif
1487 #ifdef INET6
1488         struct ip6_moptions *im6o = &cif->cif_im6o;
1489         struct in6_mfilter *im6f;
1490 #endif
1491         sx_assert(&carp_sx, SA_XLOCKED);
1492
1493         switch (sa) {
1494 #ifdef INET
1495         case AF_INET:
1496                 if (cif->cif_naddrs != 0)
1497                         break;
1498
1499                 while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1500                         ip_mfilter_remove(&imo->imo_head, imf);
1501                         in_leavegroup(imf->imf_inm, NULL);
1502                         ip_mfilter_free(imf);
1503                 }
1504                 break;
1505 #endif
1506 #ifdef INET6
1507         case AF_INET6:
1508                 if (cif->cif_naddrs6 != 0)
1509                         break;
1510
1511                 while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1512                         ip6_mfilter_remove(&im6o->im6o_head, im6f);
1513                         in6_leavegroup(im6f->im6f_in6m, NULL);
1514                         ip6_mfilter_free(im6f);
1515                 }
1516                 break;
1517 #endif
1518         }
1519 }
1520
1521 int
1522 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1523 {
1524         struct m_tag *mtag;
1525         struct carp_softc *sc;
1526
1527         if (!sa)
1528                 return (0);
1529
1530         switch (sa->sa_family) {
1531 #ifdef INET
1532         case AF_INET:
1533                 break;
1534 #endif
1535 #ifdef INET6
1536         case AF_INET6:
1537                 break;
1538 #endif
1539         default:
1540                 return (0);
1541         }
1542
1543         mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1544         if (mtag == NULL)
1545                 return (0);
1546
1547         bcopy(mtag + 1, &sc, sizeof(sc));
1548
1549         /* Set the source MAC address to the Virtual Router MAC Address. */
1550         switch (ifp->if_type) {
1551         case IFT_ETHER:
1552         case IFT_BRIDGE:
1553         case IFT_L2VLAN: {
1554                         struct ether_header *eh;
1555
1556                         eh = mtod(m, struct ether_header *);
1557                         eh->ether_shost[0] = 0;
1558                         eh->ether_shost[1] = 0;
1559                         eh->ether_shost[2] = 0x5e;
1560                         eh->ether_shost[3] = 0;
1561                         eh->ether_shost[4] = 1;
1562                         eh->ether_shost[5] = sc->sc_vhid;
1563                 }
1564                 break;
1565         default:
1566                 printf("%s: carp is not supported for the %d interface type\n",
1567                     ifp->if_xname, ifp->if_type);
1568                 return (EOPNOTSUPP);
1569         }
1570
1571         return (0);
1572 }
1573
1574 static struct carp_softc*
1575 carp_alloc(struct ifnet *ifp)
1576 {
1577         struct carp_softc *sc;
1578         struct carp_if *cif;
1579
1580         sx_assert(&carp_sx, SA_XLOCKED);
1581
1582         if ((cif = ifp->if_carp) == NULL)
1583                 cif = carp_alloc_if(ifp);
1584
1585         sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1586
1587         sc->sc_advbase = CARP_DFLTINTV;
1588         sc->sc_vhid = -1;       /* required setting */
1589         sc->sc_init_counter = 1;
1590         sc->sc_state = INIT;
1591
1592         sc->sc_ifasiz = sizeof(struct ifaddr *);
1593         sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1594         sc->sc_carpdev = ifp;
1595
1596         CARP_LOCK_INIT(sc);
1597 #ifdef INET
1598         callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1599 #endif
1600 #ifdef INET6
1601         callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1602 #endif
1603         callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1604
1605         CIF_LOCK(cif);
1606         TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1607         CIF_UNLOCK(cif);
1608
1609         mtx_lock(&carp_mtx);
1610         LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1611         mtx_unlock(&carp_mtx);
1612
1613         return (sc);
1614 }
1615
1616 static void
1617 carp_grow_ifas(struct carp_softc *sc)
1618 {
1619         struct ifaddr **new;
1620
1621         new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1622         CARP_LOCK(sc);
1623         bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1624         free(sc->sc_ifas, M_CARP);
1625         sc->sc_ifas = new;
1626         sc->sc_ifasiz *= 2;
1627         CARP_UNLOCK(sc);
1628 }
1629
1630 static void
1631 carp_destroy(struct carp_softc *sc)
1632 {
1633         struct ifnet *ifp = sc->sc_carpdev;
1634         struct carp_if *cif = ifp->if_carp;
1635
1636         sx_assert(&carp_sx, SA_XLOCKED);
1637
1638         if (sc->sc_suppress)
1639                 carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1640         CARP_UNLOCK(sc);
1641
1642         CIF_LOCK(cif);
1643         TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1644         CIF_UNLOCK(cif);
1645
1646         mtx_lock(&carp_mtx);
1647         LIST_REMOVE(sc, sc_next);
1648         mtx_unlock(&carp_mtx);
1649
1650         callout_drain(&sc->sc_ad_tmo);
1651 #ifdef INET
1652         callout_drain(&sc->sc_md_tmo);
1653 #endif
1654 #ifdef INET6
1655         callout_drain(&sc->sc_md6_tmo);
1656 #endif
1657         CARP_LOCK_DESTROY(sc);
1658
1659         free(sc->sc_ifas, M_CARP);
1660         free(sc, M_CARP);
1661 }
1662
1663 static struct carp_if*
1664 carp_alloc_if(struct ifnet *ifp)
1665 {
1666         struct carp_if *cif;
1667         int error;
1668
1669         cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1670
1671         if ((error = ifpromisc(ifp, 1)) != 0)
1672                 printf("%s: ifpromisc(%s) failed: %d\n",
1673                     __func__, ifp->if_xname, error);
1674         else
1675                 cif->cif_flags |= CIF_PROMISC;
1676
1677         CIF_LOCK_INIT(cif);
1678         cif->cif_ifp = ifp;
1679         TAILQ_INIT(&cif->cif_vrs);
1680
1681         IF_ADDR_WLOCK(ifp);
1682         ifp->if_carp = cif;
1683         if_ref(ifp);
1684         IF_ADDR_WUNLOCK(ifp);
1685
1686         return (cif);
1687 }
1688
1689 static void
1690 carp_free_if(struct carp_if *cif)
1691 {
1692         struct ifnet *ifp = cif->cif_ifp;
1693
1694         CIF_LOCK_ASSERT(cif);
1695         KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1696             __func__));
1697
1698         IF_ADDR_WLOCK(ifp);
1699         ifp->if_carp = NULL;
1700         IF_ADDR_WUNLOCK(ifp);
1701
1702         CIF_LOCK_DESTROY(cif);
1703
1704         if (cif->cif_flags & CIF_PROMISC)
1705                 ifpromisc(ifp, 0);
1706         if_rele(ifp);
1707
1708         free(cif, M_CARP);
1709 }
1710
1711 static void
1712 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1713 {
1714
1715         CARP_LOCK(sc);
1716         carpr->carpr_state = sc->sc_state;
1717         carpr->carpr_vhid = sc->sc_vhid;
1718         carpr->carpr_advbase = sc->sc_advbase;
1719         carpr->carpr_advskew = sc->sc_advskew;
1720         if (priv)
1721                 bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1722         else
1723                 bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1724         CARP_UNLOCK(sc);
1725 }
1726
1727 int
1728 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1729 {
1730         struct carpreq carpr;
1731         struct ifnet *ifp;
1732         struct carp_softc *sc = NULL;
1733         int error = 0, locked = 0;
1734
1735         if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1736                 return (error);
1737
1738         ifp = ifunit_ref(ifr->ifr_name);
1739         if (ifp == NULL)
1740                 return (ENXIO);
1741
1742         switch (ifp->if_type) {
1743         case IFT_ETHER:
1744         case IFT_L2VLAN:
1745         case IFT_BRIDGE:
1746                 break;
1747         default:
1748                 error = EOPNOTSUPP;
1749                 goto out;
1750         }
1751
1752         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1753                 error = EADDRNOTAVAIL;
1754                 goto out;
1755         }
1756
1757         sx_xlock(&carp_sx);
1758         switch (cmd) {
1759         case SIOCSVH:
1760                 if ((error = priv_check(td, PRIV_NETINET_CARP)))
1761                         break;
1762                 if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1763                     carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1764                         error = EINVAL;
1765                         break;
1766                 }
1767
1768                 if (ifp->if_carp) {
1769                         IFNET_FOREACH_CARP(ifp, sc)
1770                                 if (sc->sc_vhid == carpr.carpr_vhid)
1771                                         break;
1772                 }
1773                 if (sc == NULL) {
1774                         sc = carp_alloc(ifp);
1775                         CARP_LOCK(sc);
1776                         sc->sc_vhid = carpr.carpr_vhid;
1777                         LLADDR(&sc->sc_addr)[0] = 0;
1778                         LLADDR(&sc->sc_addr)[1] = 0;
1779                         LLADDR(&sc->sc_addr)[2] = 0x5e;
1780                         LLADDR(&sc->sc_addr)[3] = 0;
1781                         LLADDR(&sc->sc_addr)[4] = 1;
1782                         LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1783                 } else
1784                         CARP_LOCK(sc);
1785                 locked = 1;
1786                 if (carpr.carpr_advbase > 0) {
1787                         if (carpr.carpr_advbase > 255 ||
1788                             carpr.carpr_advbase < CARP_DFLTINTV) {
1789                                 error = EINVAL;
1790                                 break;
1791                         }
1792                         sc->sc_advbase = carpr.carpr_advbase;
1793                 }
1794                 if (carpr.carpr_advskew >= 255) {
1795                         error = EINVAL;
1796                         break;
1797                 }
1798                 sc->sc_advskew = carpr.carpr_advskew;
1799                 if (carpr.carpr_key[0] != '\0') {
1800                         bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1801                         carp_hmac_prepare(sc);
1802                 }
1803                 if (sc->sc_state != INIT &&
1804                     carpr.carpr_state != sc->sc_state) {
1805                         switch (carpr.carpr_state) {
1806                         case BACKUP:
1807                                 callout_stop(&sc->sc_ad_tmo);
1808                                 carp_set_state(sc, BACKUP,
1809                                     "user requested via ifconfig");
1810                                 carp_setrun(sc, 0);
1811                                 carp_delroute(sc);
1812                                 break;
1813                         case MASTER:
1814                                 carp_master_down_locked(sc,
1815                                     "user requested via ifconfig");
1816                                 break;
1817                         default:
1818                                 break;
1819                         }
1820                 }
1821                 break;
1822
1823         case SIOCGVH:
1824             {
1825                 int priveleged;
1826
1827                 if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1828                         error = EINVAL;
1829                         break;
1830                 }
1831                 if (carpr.carpr_count < 1) {
1832                         error = EMSGSIZE;
1833                         break;
1834                 }
1835                 if (ifp->if_carp == NULL) {
1836                         error = ENOENT;
1837                         break;
1838                 }
1839
1840                 priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1841                 if (carpr.carpr_vhid != 0) {
1842                         IFNET_FOREACH_CARP(ifp, sc)
1843                                 if (sc->sc_vhid == carpr.carpr_vhid)
1844                                         break;
1845                         if (sc == NULL) {
1846                                 error = ENOENT;
1847                                 break;
1848                         }
1849                         carp_carprcp(&carpr, sc, priveleged);
1850                         error = copyout(&carpr, ifr_data_get_ptr(ifr),
1851                             sizeof(carpr));
1852                 } else  {
1853                         int i, count;
1854
1855                         count = 0;
1856                         IFNET_FOREACH_CARP(ifp, sc)
1857                                 count++;
1858
1859                         if (count > carpr.carpr_count) {
1860                                 CIF_UNLOCK(ifp->if_carp);
1861                                 error = EMSGSIZE;
1862                                 break;
1863                         }
1864
1865                         i = 0;
1866                         IFNET_FOREACH_CARP(ifp, sc) {
1867                                 carp_carprcp(&carpr, sc, priveleged);
1868                                 carpr.carpr_count = count;
1869                                 error = copyout(&carpr,
1870                                     (char *)ifr_data_get_ptr(ifr) +
1871                                     (i * sizeof(carpr)), sizeof(carpr));
1872                                 if (error) {
1873                                         CIF_UNLOCK(ifp->if_carp);
1874                                         break;
1875                                 }
1876                                 i++;
1877                         }
1878                 }
1879                 break;
1880             }
1881         default:
1882                 error = EINVAL;
1883         }
1884         sx_xunlock(&carp_sx);
1885
1886 out:
1887         if (locked)
1888                 CARP_UNLOCK(sc);
1889         if_rele(ifp);
1890
1891         return (error);
1892 }
1893
1894 static int
1895 carp_get_vhid(struct ifaddr *ifa)
1896 {
1897
1898         if (ifa == NULL || ifa->ifa_carp == NULL)
1899                 return (0);
1900
1901         return (ifa->ifa_carp->sc_vhid);
1902 }
1903
1904 int
1905 carp_attach(struct ifaddr *ifa, int vhid)
1906 {
1907         struct ifnet *ifp = ifa->ifa_ifp;
1908         struct carp_if *cif = ifp->if_carp;
1909         struct carp_softc *sc;
1910         int index, error;
1911
1912         KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1913
1914         switch (ifa->ifa_addr->sa_family) {
1915 #ifdef INET
1916         case AF_INET:
1917 #endif
1918 #ifdef INET6
1919         case AF_INET6:
1920 #endif
1921                 break;
1922         default:
1923                 return (EPROTOTYPE);
1924         }
1925
1926         sx_xlock(&carp_sx);
1927         if (ifp->if_carp == NULL) {
1928                 sx_xunlock(&carp_sx);
1929                 return (ENOPROTOOPT);
1930         }
1931
1932         IFNET_FOREACH_CARP(ifp, sc)
1933                 if (sc->sc_vhid == vhid)
1934                         break;
1935         if (sc == NULL) {
1936                 sx_xunlock(&carp_sx);
1937                 return (ENOENT);
1938         }
1939
1940         error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1941         if (error) {
1942                 CIF_FREE(cif);
1943                 sx_xunlock(&carp_sx);
1944                 return (error);
1945         }
1946
1947         index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1948         if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1949                 carp_grow_ifas(sc);
1950
1951         switch (ifa->ifa_addr->sa_family) {
1952 #ifdef INET
1953         case AF_INET:
1954                 cif->cif_naddrs++;
1955                 sc->sc_naddrs++;
1956                 break;
1957 #endif
1958 #ifdef INET6
1959         case AF_INET6:
1960                 cif->cif_naddrs6++;
1961                 sc->sc_naddrs6++;
1962                 break;
1963 #endif
1964         }
1965
1966         ifa_ref(ifa);
1967
1968         CARP_LOCK(sc);
1969         sc->sc_ifas[index - 1] = ifa;
1970         ifa->ifa_carp = sc;
1971         carp_hmac_prepare(sc);
1972         carp_sc_state(sc);
1973         CARP_UNLOCK(sc);
1974
1975         sx_xunlock(&carp_sx);
1976
1977         return (0);
1978 }
1979
1980 void
1981 carp_detach(struct ifaddr *ifa, bool keep_cif)
1982 {
1983         struct ifnet *ifp = ifa->ifa_ifp;
1984         struct carp_if *cif = ifp->if_carp;
1985         struct carp_softc *sc = ifa->ifa_carp;
1986         int i, index;
1987
1988         KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1989
1990         sx_xlock(&carp_sx);
1991
1992         CARP_LOCK(sc);
1993         /* Shift array. */
1994         index = sc->sc_naddrs + sc->sc_naddrs6;
1995         for (i = 0; i < index; i++)
1996                 if (sc->sc_ifas[i] == ifa)
1997                         break;
1998         KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
1999         for (; i < index - 1; i++)
2000                 sc->sc_ifas[i] = sc->sc_ifas[i+1];
2001         sc->sc_ifas[index - 1] = NULL;
2002
2003         switch (ifa->ifa_addr->sa_family) {
2004 #ifdef INET
2005         case AF_INET:
2006                 cif->cif_naddrs--;
2007                 sc->sc_naddrs--;
2008                 break;
2009 #endif
2010 #ifdef INET6
2011         case AF_INET6:
2012                 cif->cif_naddrs6--;
2013                 sc->sc_naddrs6--;
2014                 break;
2015 #endif
2016         }
2017
2018         carp_ifa_delroute(ifa);
2019         carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
2020
2021         ifa->ifa_carp = NULL;
2022         ifa_free(ifa);
2023
2024         carp_hmac_prepare(sc);
2025         carp_sc_state(sc);
2026
2027         if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2028                 carp_destroy(sc);
2029         else
2030                 CARP_UNLOCK(sc);
2031
2032         if (!keep_cif)
2033                 CIF_FREE(cif);
2034
2035         sx_xunlock(&carp_sx);
2036 }
2037
2038 static void
2039 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2040 {
2041
2042         CARP_LOCK_ASSERT(sc);
2043
2044         if (sc->sc_state != state) {
2045                 const char *carp_states[] = { CARP_STATES };
2046                 char subsys[IFNAMSIZ+5];
2047
2048                 snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2049                     sc->sc_carpdev->if_xname);
2050
2051                 CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2052                     carp_states[sc->sc_state], carp_states[state], reason);
2053
2054                 sc->sc_state = state;
2055
2056                 devctl_notify("CARP", subsys, carp_states[state], NULL);
2057         }
2058 }
2059
2060 static void
2061 carp_linkstate(struct ifnet *ifp)
2062 {
2063         struct carp_softc *sc;
2064
2065         CIF_LOCK(ifp->if_carp);
2066         IFNET_FOREACH_CARP(ifp, sc) {
2067                 CARP_LOCK(sc);
2068                 carp_sc_state(sc);
2069                 CARP_UNLOCK(sc);
2070         }
2071         CIF_UNLOCK(ifp->if_carp);
2072 }
2073
2074 static void
2075 carp_sc_state(struct carp_softc *sc)
2076 {
2077
2078         CARP_LOCK_ASSERT(sc);
2079
2080         if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2081             !(sc->sc_carpdev->if_flags & IFF_UP) ||
2082             !V_carp_allow) {
2083                 callout_stop(&sc->sc_ad_tmo);
2084 #ifdef INET
2085                 callout_stop(&sc->sc_md_tmo);
2086 #endif
2087 #ifdef INET6
2088                 callout_stop(&sc->sc_md6_tmo);
2089 #endif
2090                 carp_set_state(sc, INIT, "hardware interface down");
2091                 carp_setrun(sc, 0);
2092                 if (!sc->sc_suppress)
2093                         carp_demote_adj(V_carp_ifdown_adj, "interface down");
2094                 sc->sc_suppress = 1;
2095         } else {
2096                 carp_set_state(sc, INIT, "hardware interface up");
2097                 carp_setrun(sc, 0);
2098                 if (sc->sc_suppress)
2099                         carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2100                 sc->sc_suppress = 0;
2101         }
2102 }
2103
2104 static void
2105 carp_demote_adj(int adj, char *reason)
2106 {
2107         atomic_add_int(&V_carp_demotion, adj);
2108         CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2109         taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2110 }
2111
2112 static int
2113 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2114 {
2115         int new, error;
2116         struct carp_softc *sc;
2117
2118         new = V_carp_allow;
2119         error = sysctl_handle_int(oidp, &new, 0, req);
2120         if (error || !req->newptr)
2121                 return (error);
2122
2123         if (V_carp_allow != new) {
2124                 V_carp_allow = new;
2125
2126                 mtx_lock(&carp_mtx);
2127                 LIST_FOREACH(sc, &carp_list, sc_next) {
2128                         CARP_LOCK(sc);
2129                         if (curvnet == sc->sc_carpdev->if_vnet)
2130                                 carp_sc_state(sc);
2131                         CARP_UNLOCK(sc);
2132                 }
2133                 mtx_unlock(&carp_mtx);
2134         }
2135
2136         return (0);
2137 }
2138
2139 static int
2140 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2141 {
2142         int new, error;
2143
2144         new = V_carp_dscp;
2145         error = sysctl_handle_int(oidp, &new, 0, req);
2146         if (error || !req->newptr)
2147                 return (error);
2148
2149         if (new < 0 || new > 63)
2150                 return (EINVAL);
2151
2152         V_carp_dscp = new;
2153
2154         return (0);
2155 }
2156
2157 static int
2158 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2159 {
2160         int new, error;
2161
2162         new = V_carp_demotion;
2163         error = sysctl_handle_int(oidp, &new, 0, req);
2164         if (error || !req->newptr)
2165                 return (error);
2166
2167         carp_demote_adj(new, "sysctl");
2168
2169         return (0);
2170 }
2171
2172 static void
2173 carp_mod_cleanup(void)
2174 {
2175
2176 #ifdef INET
2177         (void)ipproto_unregister(IPPROTO_CARP);
2178         carp_iamatch_p = NULL;
2179 #endif
2180 #ifdef INET6
2181         (void)ip6proto_unregister(IPPROTO_CARP);
2182         carp_iamatch6_p = NULL;
2183         carp_macmatch6_p = NULL;
2184 #endif
2185         carp_ioctl_p = NULL;
2186         carp_attach_p = NULL;
2187         carp_detach_p = NULL;
2188         carp_get_vhid_p = NULL;
2189         carp_linkstate_p = NULL;
2190         carp_forus_p = NULL;
2191         carp_output_p = NULL;
2192         carp_demote_adj_p = NULL;
2193         carp_master_p = NULL;
2194         mtx_unlock(&carp_mtx);
2195         taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2196         mtx_destroy(&carp_mtx);
2197         sx_destroy(&carp_sx);
2198 }
2199
2200 static int
2201 carp_mod_load(void)
2202 {
2203         int err;
2204
2205         mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2206         sx_init(&carp_sx, "carp_sx");
2207         LIST_INIT(&carp_list);
2208         carp_get_vhid_p = carp_get_vhid;
2209         carp_forus_p = carp_forus;
2210         carp_output_p = carp_output;
2211         carp_linkstate_p = carp_linkstate;
2212         carp_ioctl_p = carp_ioctl;
2213         carp_attach_p = carp_attach;
2214         carp_detach_p = carp_detach;
2215         carp_demote_adj_p = carp_demote_adj;
2216         carp_master_p = carp_master;
2217 #ifdef INET6
2218         carp_iamatch6_p = carp_iamatch6;
2219         carp_macmatch6_p = carp_macmatch6;
2220         err = ip6proto_register(IPPROTO_CARP, carp6_input, NULL);
2221         if (err) {
2222                 printf("carp: error %d registering with INET6\n", err);
2223                 carp_mod_cleanup();
2224                 return (err);
2225         }
2226 #endif
2227 #ifdef INET
2228         carp_iamatch_p = carp_iamatch;
2229         err = ipproto_register(IPPROTO_CARP, carp_input, NULL);
2230         if (err) {
2231                 printf("carp: error %d registering with INET\n", err);
2232                 carp_mod_cleanup();
2233                 return (err);
2234         }
2235 #endif
2236         return (0);
2237 }
2238
2239 static int
2240 carp_modevent(module_t mod, int type, void *data)
2241 {
2242         switch (type) {
2243         case MOD_LOAD:
2244                 return carp_mod_load();
2245                 /* NOTREACHED */
2246         case MOD_UNLOAD:
2247                 mtx_lock(&carp_mtx);
2248                 if (LIST_EMPTY(&carp_list))
2249                         carp_mod_cleanup();
2250                 else {
2251                         mtx_unlock(&carp_mtx);
2252                         return (EBUSY);
2253                 }
2254                 break;
2255
2256         default:
2257                 return (EINVAL);
2258         }
2259
2260         return (0);
2261 }
2262
2263 static moduledata_t carp_mod = {
2264         "carp",
2265         carp_modevent,
2266         0
2267 };
2268
2269 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);