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/protosw.h>
  50 #include <sys/socket.h>
  51 #include <sys/sockio.h>
  52 #include <sys/sysctl.h>
  53 #include <sys/syslog.h>
  54 #include <sys/taskqueue.h>
  55 #include <sys/counter.h>
  56
  57 #include <net/ethernet.h>
  58 #include <net/if.h>
  59 #include <net/if_var.h>
  60 #include <net/if_dl.h>
  61 #include <net/if_llatbl.h>
  62 #include <net/if_types.h>
  63 #include <net/route.h>
  64 #include <net/vnet.h>
  65
  66 #if defined(INET) || defined(INET6)
  67 #include <netinet/in.h>
  68 #include <netinet/in_var.h>
  69 #include <netinet/ip_carp.h>
  70 #include <netinet/ip.h>
  71 #include <machine/in_cksum.h>
  72 #endif
  73 #ifdef INET
  74 #include <netinet/ip_var.h>
  75 #include <netinet/if_ether.h>
  76 #endif
  77
  78 #ifdef INET6
  79 #include <netinet/icmp6.h>
  80 #include <netinet/ip6.h>
  81 #include <netinet6/in6_var.h>
  82 #include <netinet6/ip6_var.h>
  83 #include <netinet6/scope6_var.h>
  84 #include <netinet6/nd6.h>
  85 #endif
  86
  87 #include <crypto/sha1.h>
  88
  89 static MALLOC_DEFINE(M_CARP, "CARP", "CARP addresses");
  90
  91 struct carp_softc {
  92         struct ifnet            *sc_carpdev;    /* Pointer to parent ifnet. */
  93         struct ifaddr           **sc_ifas;      /* Our ifaddrs. */
  94         struct sockaddr_dl      sc_addr;        /* Our link level address. */
  95         struct callout          sc_ad_tmo;      /* Advertising timeout. */
  96 #ifdef INET
  97         struct callout          sc_md_tmo;      /* Master down timeout. */
  98 #endif
  99 #ifdef INET6
 100         struct callout          sc_md6_tmo;     /* XXX: Master down timeout. */
 101 #endif
 102         struct mtx              sc_mtx;
 103
 104         int                     sc_vhid;
 105         int                     sc_advskew;
 106         int                     sc_advbase;
 107
 108         int                     sc_naddrs;
 109         int                     sc_naddrs6;
 110         int                     sc_ifasiz;
 111         enum { INIT = 0, BACKUP, MASTER }       sc_state;
 112         int                     sc_suppress;
 113         int                     sc_sendad_errors;
 114 #define CARP_SENDAD_MAX_ERRORS  3
 115         int                     sc_sendad_success;
 116 #define CARP_SENDAD_MIN_SUCCESS 3
 117
 118         int                     sc_init_counter;
 119         uint64_t                sc_counter;
 120
 121         /* authentication */
 122 #define CARP_HMAC_PAD   64
 123         unsigned char sc_key[CARP_KEY_LEN];
 124         unsigned char sc_pad[CARP_HMAC_PAD];
 125         SHA1_CTX sc_sha1;
 126
 127         TAILQ_ENTRY(carp_softc) sc_list;        /* On the carp_if list. */
 128         LIST_ENTRY(carp_softc)  sc_next;        /* On the global list. */
 129 };
 130
 131 struct carp_if {
 132 #ifdef INET
 133         int     cif_naddrs;
 134 #endif
 135 #ifdef INET6
 136         int     cif_naddrs6;
 137 #endif
 138         TAILQ_HEAD(, carp_softc) cif_vrs;
 139 #ifdef INET
 140         struct ip_moptions       cif_imo;
 141 #endif
 142 #ifdef INET6
 143         struct ip6_moptions      cif_im6o;
 144 #endif
 145         struct ifnet    *cif_ifp;
 146         struct mtx      cif_mtx;
 147         uint32_t        cif_flags;
 148 #define CIF_PROMISC     0x00000001
 149 };
 150
 151 #define CARP_INET       0
 152 #define CARP_INET6      1
 153 static int proto_reg[] = {-1, -1};
 154
 155 /*
 156  * Brief design of carp(4).
 157  *
 158  * Any carp-capable ifnet may have a list of carp softcs hanging off
 159  * its ifp->if_carp pointer. Each softc represents one unique virtual
 160  * host id, or vhid. The softc has a back pointer to the ifnet. All
 161  * softcs are joined in a global list, which has quite limited use.
 162  *
 163  * Any interface address that takes part in CARP negotiation has a
 164  * pointer to the softc of its vhid, ifa->ifa_carp. That could be either
 165  * AF_INET or AF_INET6 address.
 166  *
 167  * Although, one can get the softc's backpointer to ifnet and traverse
 168  * through its ifp->if_addrhead queue to find all interface addresses
 169  * involved in CARP, we keep a growable array of ifaddr pointers. This
 170  * allows us to avoid grabbing the IF_ADDR_LOCK() in many traversals that
 171  * do calls into the network stack, thus avoiding LORs.
 172  *
 173  * Locking:
 174  *
 175  * Each softc has a lock sc_mtx. It is used to synchronise carp_input_c(),
 176  * callout-driven events and ioctl()s.
 177  *
 178  * To traverse the list of softcs on an ifnet we use CIF_LOCK() or carp_sx.
 179  * To traverse the global list we use the mutex carp_mtx.
 180  *
 181  * Known issues with locking:
 182  *
 183  * - Sending ad, we put the pointer to the softc in an mtag, and no reference
 184  *   counting is done on the softc.
 185  * - On module unload we may race (?) with packet processing thread
 186  *   dereferencing our function pointers.
 187  */
 188
 189 /* Accept incoming CARP packets. */
 190 VNET_DEFINE_STATIC(int, carp_allow) = 1;
 191 #define V_carp_allow    VNET(carp_allow)
 192
 193 /* Set DSCP in outgoing CARP packets. */
 194 VNET_DEFINE_STATIC(int, carp_dscp) = 56;
 195 #define V_carp_dscp     VNET(carp_dscp)
 196
 197 /* Preempt slower nodes. */
 198 VNET_DEFINE_STATIC(int, carp_preempt) = 0;
 199 #define V_carp_preempt  VNET(carp_preempt)
 200
 201 /* Log level. */
 202 VNET_DEFINE_STATIC(int, carp_log) = 1;
 203 #define V_carp_log      VNET(carp_log)
 204
 205 /* Global advskew demotion. */
 206 VNET_DEFINE_STATIC(int, carp_demotion) = 0;
 207 #define V_carp_demotion VNET(carp_demotion)
 208
 209 /* Send error demotion factor. */
 210 VNET_DEFINE_STATIC(int, carp_senderr_adj) = CARP_MAXSKEW;
 211 #define V_carp_senderr_adj      VNET(carp_senderr_adj)
 212
 213 /* Iface down demotion factor. */
 214 VNET_DEFINE_STATIC(int, carp_ifdown_adj) = CARP_MAXSKEW;
 215 #define V_carp_ifdown_adj       VNET(carp_ifdown_adj)
 216
 217 static int carp_allow_sysctl(SYSCTL_HANDLER_ARGS);
 218 static int carp_dscp_sysctl(SYSCTL_HANDLER_ARGS);
 219 static int carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS);
 220
 221 SYSCTL_NODE(_net_inet, IPPROTO_CARP, carp, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
 222     "CARP");
 223 SYSCTL_PROC(_net_inet_carp, OID_AUTO, allow,
 224     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 225     0, 0, carp_allow_sysctl, "I",
 226     "Accept incoming CARP packets");
 227 SYSCTL_PROC(_net_inet_carp, OID_AUTO, dscp,
 228     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 229     0, 0, carp_dscp_sysctl, "I",
 230     "DSCP value for carp packets");
 231 SYSCTL_INT(_net_inet_carp, OID_AUTO, preempt, CTLFLAG_VNET | CTLFLAG_RW,
 232     &VNET_NAME(carp_preempt), 0, "High-priority backup preemption mode");
 233 SYSCTL_INT(_net_inet_carp, OID_AUTO, log, CTLFLAG_VNET | CTLFLAG_RW,
 234     &VNET_NAME(carp_log), 0, "CARP log level");
 235 SYSCTL_PROC(_net_inet_carp, OID_AUTO, demotion,
 236     CTLFLAG_VNET | CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
 237     0, 0, carp_demote_adj_sysctl, "I",
 238     "Adjust demotion factor (skew of advskew)");
 239 SYSCTL_INT(_net_inet_carp, OID_AUTO, senderr_demotion_factor,
 240     CTLFLAG_VNET | CTLFLAG_RW,
 241     &VNET_NAME(carp_senderr_adj), 0, "Send error demotion factor adjustment");
 242 SYSCTL_INT(_net_inet_carp, OID_AUTO, ifdown_demotion_factor,
 243     CTLFLAG_VNET | CTLFLAG_RW,
 244     &VNET_NAME(carp_ifdown_adj), 0,
 245     "Interface down demotion factor adjustment");
 246
 247 VNET_PCPUSTAT_DEFINE(struct carpstats, carpstats);
 248 VNET_PCPUSTAT_SYSINIT(carpstats);
 249 VNET_PCPUSTAT_SYSUNINIT(carpstats);
 250
 251 #define CARPSTATS_ADD(name, val)        \
 252     counter_u64_add(VNET(carpstats)[offsetof(struct carpstats, name) / \
 253         sizeof(uint64_t)], (val))
 254 #define CARPSTATS_INC(name)             CARPSTATS_ADD(name, 1)
 255
 256 SYSCTL_VNET_PCPUSTAT(_net_inet_carp, OID_AUTO, stats, struct carpstats,
 257     carpstats, "CARP statistics (struct carpstats, netinet/ip_carp.h)");
 258
 259 #define CARP_LOCK_INIT(sc)      mtx_init(&(sc)->sc_mtx, "carp_softc",   \
 260         NULL, MTX_DEF)
 261 #define CARP_LOCK_DESTROY(sc)   mtx_destroy(&(sc)->sc_mtx)
 262 #define CARP_LOCK_ASSERT(sc)    mtx_assert(&(sc)->sc_mtx, MA_OWNED)
 263 #define CARP_LOCK(sc)           mtx_lock(&(sc)->sc_mtx)
 264 #define CARP_UNLOCK(sc)         mtx_unlock(&(sc)->sc_mtx)
 265 #define CIF_LOCK_INIT(cif)      mtx_init(&(cif)->cif_mtx, "carp_if",   \
 266         NULL, MTX_DEF)
 267 #define CIF_LOCK_DESTROY(cif)   mtx_destroy(&(cif)->cif_mtx)
 268 #define CIF_LOCK_ASSERT(cif)    mtx_assert(&(cif)->cif_mtx, MA_OWNED)
 269 #define CIF_LOCK(cif)           mtx_lock(&(cif)->cif_mtx)
 270 #define CIF_UNLOCK(cif)         mtx_unlock(&(cif)->cif_mtx)
 271 #define CIF_FREE(cif)   do {                            \
 272                 CIF_LOCK(cif);                          \
 273                 if (TAILQ_EMPTY(&(cif)->cif_vrs))       \
 274                         carp_free_if(cif);              \
 275                 else                                    \
 276                         CIF_UNLOCK(cif);                \
 277 } while (0)
 278
 279 #define CARP_LOG(...)   do {                            \
 280         if (V_carp_log > 0)                             \
 281                 log(LOG_INFO, "carp: " __VA_ARGS__);    \
 282 } while (0)
 283
 284 #define CARP_DEBUG(...) do {                            \
 285         if (V_carp_log > 1)                             \
 286                 log(LOG_DEBUG, __VA_ARGS__);            \
 287 } while (0)
 288
 289 #define IFNET_FOREACH_IFA(ifp, ifa)                                     \
 290         CK_STAILQ_FOREACH((ifa), &(ifp)->if_addrhead, ifa_link) \
 291                 if ((ifa)->ifa_carp != NULL)
 292
 293 #define CARP_FOREACH_IFA(sc, ifa)                                       \
 294         CARP_LOCK_ASSERT(sc);                                           \
 295         for (int _i = 0;                                                \
 296                 _i < (sc)->sc_naddrs + (sc)->sc_naddrs6 &&              \
 297                 ((ifa) = sc->sc_ifas[_i]) != NULL;                      \
 298                 ++_i)
 299
 300 #define IFNET_FOREACH_CARP(ifp, sc)                                     \
 301         KASSERT(mtx_owned(&ifp->if_carp->cif_mtx) ||                    \
 302             sx_xlocked(&carp_sx), ("cif_vrs not locked"));              \
 303         TAILQ_FOREACH((sc), &(ifp)->if_carp->cif_vrs, sc_list)
 304
 305 #define DEMOTE_ADVSKEW(sc)                                      \
 306     (((sc)->sc_advskew + V_carp_demotion > CARP_MAXSKEW) ?      \
 307     CARP_MAXSKEW :                                              \
 308         (((sc)->sc_advskew + V_carp_demotion < 0) ?             \
 309         0 : ((sc)->sc_advskew + V_carp_demotion)))
 310
 311 static void     carp_input_c(struct mbuf *, struct carp_header *, sa_family_t);
 312 static struct carp_softc
 313                 *carp_alloc(struct ifnet *);
 314 static void     carp_destroy(struct carp_softc *);
 315 static struct carp_if
 316                 *carp_alloc_if(struct ifnet *);
 317 static void     carp_free_if(struct carp_if *);
 318 static void     carp_set_state(struct carp_softc *, int, const char* reason);
 319 static void     carp_sc_state(struct carp_softc *);
 320 static void     carp_setrun(struct carp_softc *, sa_family_t);
 321 static void     carp_master_down(void *);
 322 static void     carp_master_down_locked(struct carp_softc *,
 323                     const char* reason);
 324 static void     carp_send_ad(void *);
 325 static void     carp_send_ad_locked(struct carp_softc *);
 326 static void     carp_addroute(struct carp_softc *);
 327 static void     carp_ifa_addroute(struct ifaddr *);
 328 static void     carp_delroute(struct carp_softc *);
 329 static void     carp_ifa_delroute(struct ifaddr *);
 330 static void     carp_send_ad_all(void *, int);
 331 static void     carp_demote_adj(int, char *);
 332
 333 static LIST_HEAD(, carp_softc) carp_list;
 334 static struct mtx carp_mtx;
 335 static struct sx carp_sx;
 336 static struct task carp_sendall_task =
 337     TASK_INITIALIZER(0, carp_send_ad_all, NULL);
 338
 339 static void
 340 carp_hmac_prepare(struct carp_softc *sc)
 341 {
 342         uint8_t version = CARP_VERSION, type = CARP_ADVERTISEMENT;
 343         uint8_t vhid = sc->sc_vhid & 0xff;
 344         struct ifaddr *ifa;
 345         int i, found;
 346 #ifdef INET
 347         struct in_addr last, cur, in;
 348 #endif
 349 #ifdef INET6
 350         struct in6_addr last6, cur6, in6;
 351 #endif
 352
 353         CARP_LOCK_ASSERT(sc);
 354
 355         /* Compute ipad from key. */
 356         bzero(sc->sc_pad, sizeof(sc->sc_pad));
 357         bcopy(sc->sc_key, sc->sc_pad, sizeof(sc->sc_key));
 358         for (i = 0; i < sizeof(sc->sc_pad); i++)
 359                 sc->sc_pad[i] ^= 0x36;
 360
 361         /* Precompute first part of inner hash. */
 362         SHA1Init(&sc->sc_sha1);
 363         SHA1Update(&sc->sc_sha1, sc->sc_pad, sizeof(sc->sc_pad));
 364         SHA1Update(&sc->sc_sha1, (void *)&version, sizeof(version));
 365         SHA1Update(&sc->sc_sha1, (void *)&type, sizeof(type));
 366         SHA1Update(&sc->sc_sha1, (void *)&vhid, sizeof(vhid));
 367 #ifdef INET
 368         cur.s_addr = 0;
 369         do {
 370                 found = 0;
 371                 last = cur;
 372                 cur.s_addr = 0xffffffff;
 373                 CARP_FOREACH_IFA(sc, ifa) {
 374                         in.s_addr = ifatoia(ifa)->ia_addr.sin_addr.s_addr;
 375                         if (ifa->ifa_addr->sa_family == AF_INET &&
 376                             ntohl(in.s_addr) > ntohl(last.s_addr) &&
 377                             ntohl(in.s_addr) < ntohl(cur.s_addr)) {
 378                                 cur.s_addr = in.s_addr;
 379                                 found++;
 380                         }
 381                 }
 382                 if (found)
 383                         SHA1Update(&sc->sc_sha1, (void *)&cur, sizeof(cur));
 384         } while (found);
 385 #endif /* INET */
 386 #ifdef INET6
 387         memset(&cur6, 0, sizeof(cur6));
 388         do {
 389                 found = 0;
 390                 last6 = cur6;
 391                 memset(&cur6, 0xff, sizeof(cur6));
 392                 CARP_FOREACH_IFA(sc, ifa) {
 393                         in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
 394                         if (IN6_IS_SCOPE_EMBED(&in6))
 395                                 in6.s6_addr16[1] = 0;
 396                         if (ifa->ifa_addr->sa_family == AF_INET6 &&
 397                             memcmp(&in6, &last6, sizeof(in6)) > 0 &&
 398                             memcmp(&in6, &cur6, sizeof(in6)) < 0) {
 399                                 cur6 = in6;
 400                                 found++;
 401                         }
 402                 }
 403                 if (found)
 404                         SHA1Update(&sc->sc_sha1, (void *)&cur6, sizeof(cur6));
 405         } while (found);
 406 #endif /* INET6 */
 407
 408         /* convert ipad to opad */
 409         for (i = 0; i < sizeof(sc->sc_pad); i++)
 410                 sc->sc_pad[i] ^= 0x36 ^ 0x5c;
 411 }
 412
 413 static void
 414 carp_hmac_generate(struct carp_softc *sc, uint32_t counter[2],
 415     unsigned char md[20])
 416 {
 417         SHA1_CTX sha1ctx;
 418
 419         CARP_LOCK_ASSERT(sc);
 420
 421         /* fetch first half of inner hash */
 422         bcopy(&sc->sc_sha1, &sha1ctx, sizeof(sha1ctx));
 423
 424         SHA1Update(&sha1ctx, (void *)counter, sizeof(sc->sc_counter));
 425         SHA1Final(md, &sha1ctx);
 426
 427         /* outer hash */
 428         SHA1Init(&sha1ctx);
 429         SHA1Update(&sha1ctx, sc->sc_pad, sizeof(sc->sc_pad));
 430         SHA1Update(&sha1ctx, md, 20);
 431         SHA1Final(md, &sha1ctx);
 432 }
 433
 434 static int
 435 carp_hmac_verify(struct carp_softc *sc, uint32_t counter[2],
 436     unsigned char md[20])
 437 {
 438         unsigned char md2[20];
 439
 440         CARP_LOCK_ASSERT(sc);
 441
 442         carp_hmac_generate(sc, counter, md2);
 443
 444         return (bcmp(md, md2, sizeof(md2)));
 445 }
 446
 447 /*
 448  * process input packet.
 449  * we have rearranged checks order compared to the rfc,
 450  * but it seems more efficient this way or not possible otherwise.
 451  */
 452 #ifdef INET
 453 int
 454 carp_input(struct mbuf **mp, int *offp, int proto)
 455 {
 456         struct mbuf *m = *mp;
 457         struct ip *ip = mtod(m, struct ip *);
 458         struct carp_header *ch;
 459         int iplen, len;
 460
 461         iplen = *offp;
 462         *mp = NULL;
 463
 464         CARPSTATS_INC(carps_ipackets);
 465
 466         if (!V_carp_allow) {
 467                 m_freem(m);
 468                 return (IPPROTO_DONE);
 469         }
 470
 471         /* verify that the IP TTL is 255.  */
 472         if (ip->ip_ttl != CARP_DFLTTL) {
 473                 CARPSTATS_INC(carps_badttl);
 474                 CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
 475                     ip->ip_ttl,
 476                     m->m_pkthdr.rcvif->if_xname);
 477                 m_freem(m);
 478                 return (IPPROTO_DONE);
 479         }
 480
 481         iplen = ip->ip_hl << 2;
 482
 483         if (m->m_pkthdr.len < iplen + sizeof(*ch)) {
 484                 CARPSTATS_INC(carps_badlen);
 485                 CARP_DEBUG("%s: received len %zd < sizeof(struct carp_header) "
 486                     "on %s\n", __func__, m->m_len - sizeof(struct ip),
 487                     m->m_pkthdr.rcvif->if_xname);
 488                 m_freem(m);
 489                 return (IPPROTO_DONE);
 490         }
 491
 492         if (iplen + sizeof(*ch) < m->m_len) {
 493                 if ((m = m_pullup(m, iplen + sizeof(*ch))) == NULL) {
 494                         CARPSTATS_INC(carps_hdrops);
 495                         CARP_DEBUG("%s: pullup failed\n", __func__);
 496                         return (IPPROTO_DONE);
 497                 }
 498                 ip = mtod(m, struct ip *);
 499         }
 500         ch = (struct carp_header *)((char *)ip + iplen);
 501
 502         /*
 503          * verify that the received packet length is
 504          * equal to the CARP header
 505          */
 506         len = iplen + sizeof(*ch);
 507         if (len > m->m_pkthdr.len) {
 508                 CARPSTATS_INC(carps_badlen);
 509                 CARP_DEBUG("%s: packet too short %d on %s\n", __func__,
 510                     m->m_pkthdr.len,
 511                     m->m_pkthdr.rcvif->if_xname);
 512                 m_freem(m);
 513                 return (IPPROTO_DONE);
 514         }
 515
 516         if ((m = m_pullup(m, len)) == NULL) {
 517                 CARPSTATS_INC(carps_hdrops);
 518                 return (IPPROTO_DONE);
 519         }
 520         ip = mtod(m, struct ip *);
 521         ch = (struct carp_header *)((char *)ip + iplen);
 522
 523         /* verify the CARP checksum */
 524         m->m_data += iplen;
 525         if (in_cksum(m, len - iplen)) {
 526                 CARPSTATS_INC(carps_badsum);
 527                 CARP_DEBUG("%s: checksum failed on %s\n", __func__,
 528                     m->m_pkthdr.rcvif->if_xname);
 529                 m_freem(m);
 530                 return (IPPROTO_DONE);
 531         }
 532         m->m_data -= iplen;
 533
 534         carp_input_c(m, ch, AF_INET);
 535         return (IPPROTO_DONE);
 536 }
 537 #endif
 538
 539 #ifdef INET6
 540 int
 541 carp6_input(struct mbuf **mp, int *offp, int proto)
 542 {
 543         struct mbuf *m = *mp;
 544         struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
 545         struct carp_header *ch;
 546         u_int len;
 547
 548         CARPSTATS_INC(carps_ipackets6);
 549
 550         if (!V_carp_allow) {
 551                 m_freem(m);
 552                 return (IPPROTO_DONE);
 553         }
 554
 555         /* check if received on a valid carp interface */
 556         if (m->m_pkthdr.rcvif->if_carp == NULL) {
 557                 CARPSTATS_INC(carps_badif);
 558                 CARP_DEBUG("%s: packet received on non-carp interface: %s\n",
 559                     __func__, m->m_pkthdr.rcvif->if_xname);
 560                 m_freem(m);
 561                 return (IPPROTO_DONE);
 562         }
 563
 564         /* verify that the IP TTL is 255 */
 565         if (ip6->ip6_hlim != CARP_DFLTTL) {
 566                 CARPSTATS_INC(carps_badttl);
 567                 CARP_DEBUG("%s: received ttl %d != 255 on %s\n", __func__,
 568                     ip6->ip6_hlim, m->m_pkthdr.rcvif->if_xname);
 569                 m_freem(m);
 570                 return (IPPROTO_DONE);
 571         }
 572
 573         /* verify that we have a complete carp packet */
 574         if (m->m_len < *offp + sizeof(*ch)) {
 575                 len = m->m_len;
 576                 m = m_pullup(m, *offp + sizeof(*ch));
 577                 if (m == NULL) {
 578                         CARPSTATS_INC(carps_badlen);
 579                         CARP_DEBUG("%s: packet size %u too small\n", __func__, len);
 580                         return (IPPROTO_DONE);
 581                 }
 582         }
 583         ch = (struct carp_header *)(mtod(m, char *) + *offp);
 584
 585         /* verify the CARP checksum */
 586         m->m_data += *offp;
 587         if (in_cksum(m, sizeof(*ch))) {
 588                 CARPSTATS_INC(carps_badsum);
 589                 CARP_DEBUG("%s: checksum failed, on %s\n", __func__,
 590                     m->m_pkthdr.rcvif->if_xname);
 591                 m_freem(m);
 592                 return (IPPROTO_DONE);
 593         }
 594         m->m_data -= *offp;
 595
 596         carp_input_c(m, ch, AF_INET6);
 597         return (IPPROTO_DONE);
 598 }
 599 #endif /* INET6 */
 600
 601 /*
 602  * This routine should not be necessary at all, but some switches
 603  * (VMWare ESX vswitches) can echo our own packets back at us,
 604  * and we must ignore them or they will cause us to drop out of
 605  * MASTER mode.
 606  *
 607  * We cannot catch all cases of network loops.  Instead, what we
 608  * do here is catch any packet that arrives with a carp header
 609  * with a VHID of 0, that comes from an address that is our own.
 610  * These packets are by definition "from us" (even if they are from
 611  * a misconfigured host that is pretending to be us).
 612  *
 613  * The VHID test is outside this mini-function.
 614  */
 615 static int
 616 carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
 617 {
 618 #ifdef INET
 619         struct ip *ip4;
 620         struct in_addr in4;
 621 #endif
 622 #ifdef INET6
 623         struct ip6_hdr *ip6;
 624         struct in6_addr in6;
 625 #endif
 626
 627         switch (af) {
 628 #ifdef INET
 629         case AF_INET:
 630                 ip4 = mtod(m, struct ip *);
 631                 in4 = ifatoia(ifa)->ia_addr.sin_addr;
 632                 return (in4.s_addr == ip4->ip_src.s_addr);
 633 #endif
 634 #ifdef INET6
 635         case AF_INET6:
 636                 ip6 = mtod(m, struct ip6_hdr *);
 637                 in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
 638                 return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
 639 #endif
 640         default:
 641                 break;
 642         }
 643         return (0);
 644 }
 645
 646 static void
 647 carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
 648 {
 649         struct ifnet *ifp = m->m_pkthdr.rcvif;
 650         struct ifaddr *ifa, *match;
 651         struct carp_softc *sc;
 652         uint64_t tmp_counter;
 653         struct timeval sc_tv, ch_tv;
 654         int error;
 655
 656         NET_EPOCH_ASSERT();
 657
 658         /*
 659          * Verify that the VHID is valid on the receiving interface.
 660          *
 661          * There should be just one match.  If there are none
 662          * the VHID is not valid and we drop the packet.  If
 663          * there are multiple VHID matches, take just the first
 664          * one, for compatibility with previous code.  While we're
 665          * scanning, check for obvious loops in the network topology
 666          * (these should never happen, and as noted above, we may
 667          * miss real loops; this is just a double-check).
 668          */
 669         error = 0;
 670         match = NULL;
 671         IFNET_FOREACH_IFA(ifp, ifa) {
 672                 if (match == NULL && ifa->ifa_carp != NULL &&
 673                     ifa->ifa_addr->sa_family == af &&
 674                     ifa->ifa_carp->sc_vhid == ch->carp_vhid)
 675                         match = ifa;
 676                 if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
 677                         error = ELOOP;
 678         }
 679         ifa = error ? NULL : match;
 680         if (ifa != NULL)
 681                 ifa_ref(ifa);
 682
 683         if (ifa == NULL) {
 684                 if (error == ELOOP) {
 685                         CARP_DEBUG("dropping looped packet on interface %s\n",
 686                             ifp->if_xname);
 687                         CARPSTATS_INC(carps_badif);     /* ??? */
 688                 } else {
 689                         CARPSTATS_INC(carps_badvhid);
 690                 }
 691                 m_freem(m);
 692                 return;
 693         }
 694
 695         /* verify the CARP version. */
 696         if (ch->carp_version != CARP_VERSION) {
 697                 CARPSTATS_INC(carps_badver);
 698                 CARP_DEBUG("%s: invalid version %d\n", ifp->if_xname,
 699                     ch->carp_version);
 700                 ifa_free(ifa);
 701                 m_freem(m);
 702                 return;
 703         }
 704
 705         sc = ifa->ifa_carp;
 706         CARP_LOCK(sc);
 707         ifa_free(ifa);
 708
 709         if (carp_hmac_verify(sc, ch->carp_counter, ch->carp_md)) {
 710                 CARPSTATS_INC(carps_badauth);
 711                 CARP_DEBUG("%s: incorrect hash for VHID %u@%s\n", __func__,
 712                     sc->sc_vhid, ifp->if_xname);
 713                 goto out;
 714         }
 715
 716         tmp_counter = ntohl(ch->carp_counter[0]);
 717         tmp_counter = tmp_counter<<32;
 718         tmp_counter += ntohl(ch->carp_counter[1]);
 719
 720         /* XXX Replay protection goes here */
 721
 722         sc->sc_init_counter = 0;
 723         sc->sc_counter = tmp_counter;
 724
 725         sc_tv.tv_sec = sc->sc_advbase;
 726         sc_tv.tv_usec = DEMOTE_ADVSKEW(sc) * 1000000 / 256;
 727         ch_tv.tv_sec = ch->carp_advbase;
 728         ch_tv.tv_usec = ch->carp_advskew * 1000000 / 256;
 729
 730         switch (sc->sc_state) {
 731         case INIT:
 732                 break;
 733         case MASTER:
 734                 /*
 735                  * If we receive an advertisement from a master who's going to
 736                  * be more frequent than us, go into BACKUP state.
 737                  */
 738                 if (timevalcmp(&sc_tv, &ch_tv, >) ||
 739                     timevalcmp(&sc_tv, &ch_tv, ==)) {
 740                         callout_stop(&sc->sc_ad_tmo);
 741                         carp_set_state(sc, BACKUP,
 742                             "more frequent advertisement received");
 743                         carp_setrun(sc, 0);
 744                         carp_delroute(sc);
 745                 }
 746                 break;
 747         case BACKUP:
 748                 /*
 749                  * If we're pre-empting masters who advertise slower than us,
 750                  * and this one claims to be slower, treat him as down.
 751                  */
 752                 if (V_carp_preempt && timevalcmp(&sc_tv, &ch_tv, <)) {
 753                         carp_master_down_locked(sc,
 754                             "preempting a slower master");
 755                         break;
 756                 }
 757
 758                 /*
 759                  *  If the master is going to advertise at such a low frequency
 760                  *  that he's guaranteed to time out, we'd might as well just
 761                  *  treat him as timed out now.
 762                  */
 763                 sc_tv.tv_sec = sc->sc_advbase * 3;
 764                 if (timevalcmp(&sc_tv, &ch_tv, <)) {
 765                         carp_master_down_locked(sc, "master will time out");
 766                         break;
 767                 }
 768
 769                 /*
 770                  * Otherwise, we reset the counter and wait for the next
 771                  * advertisement.
 772                  */
 773                 carp_setrun(sc, af);
 774                 break;
 775         }
 776
 777 out:
 778         CARP_UNLOCK(sc);
 779         m_freem(m);
 780 }
 781
 782 static int
 783 carp_prepare_ad(struct mbuf *m, struct carp_softc *sc, struct carp_header *ch)
 784 {
 785         struct m_tag *mtag;
 786
 787         if (sc->sc_init_counter) {
 788                 /* this could also be seconds since unix epoch */
 789                 sc->sc_counter = arc4random();
 790                 sc->sc_counter = sc->sc_counter << 32;
 791                 sc->sc_counter += arc4random();
 792         } else
 793                 sc->sc_counter++;
 794
 795         ch->carp_counter[0] = htonl((sc->sc_counter>>32)&0xffffffff);
 796         ch->carp_counter[1] = htonl(sc->sc_counter&0xffffffff);
 797
 798         carp_hmac_generate(sc, ch->carp_counter, ch->carp_md);
 799
 800         /* Tag packet for carp_output */
 801         if ((mtag = m_tag_get(PACKET_TAG_CARP, sizeof(struct carp_softc *),
 802             M_NOWAIT)) == NULL) {
 803                 m_freem(m);
 804                 CARPSTATS_INC(carps_onomem);
 805                 return (ENOMEM);
 806         }
 807         bcopy(&sc, mtag + 1, sizeof(sc));
 808         m_tag_prepend(m, mtag);
 809
 810         return (0);
 811 }
 812
 813 /*
 814  * To avoid LORs and possible recursions this function shouldn't
 815  * be called directly, but scheduled via taskqueue.
 816  */
 817 static void
 818 carp_send_ad_all(void *ctx __unused, int pending __unused)
 819 {
 820         struct carp_softc *sc;
 821         struct epoch_tracker et;
 822
 823         NET_EPOCH_ENTER(et);
 824         mtx_lock(&carp_mtx);
 825         LIST_FOREACH(sc, &carp_list, sc_next)
 826                 if (sc->sc_state == MASTER) {
 827                         CARP_LOCK(sc);
 828                         CURVNET_SET(sc->sc_carpdev->if_vnet);
 829                         carp_send_ad_locked(sc);
 830                         CURVNET_RESTORE();
 831                         CARP_UNLOCK(sc);
 832                 }
 833         mtx_unlock(&carp_mtx);
 834         NET_EPOCH_EXIT(et);
 835 }
 836
 837 /* Send a periodic advertisement, executed in callout context. */
 838 static void
 839 carp_send_ad(void *v)
 840 {
 841         struct carp_softc *sc = v;
 842         struct epoch_tracker et;
 843
 844         NET_EPOCH_ENTER(et);
 845         CARP_LOCK_ASSERT(sc);
 846         CURVNET_SET(sc->sc_carpdev->if_vnet);
 847         carp_send_ad_locked(sc);
 848         CURVNET_RESTORE();
 849         CARP_UNLOCK(sc);
 850         NET_EPOCH_EXIT(et);
 851 }
 852
 853 static void
 854 carp_send_ad_error(struct carp_softc *sc, int error)
 855 {
 856
 857         /*
 858          * We track errors and successfull sends with this logic:
 859          * - Any error resets success counter to 0.
 860          * - MAX_ERRORS triggers demotion.
 861          * - MIN_SUCCESS successes resets error counter to 0.
 862          * - MIN_SUCCESS reverts demotion, if it was triggered before.
 863          */
 864         if (error) {
 865                 if (sc->sc_sendad_errors < INT_MAX)
 866                         sc->sc_sendad_errors++;
 867                 if (sc->sc_sendad_errors == CARP_SENDAD_MAX_ERRORS) {
 868                         static const char fmt[] = "send error %d on %s";
 869                         char msg[sizeof(fmt) + IFNAMSIZ];
 870
 871                         sprintf(msg, fmt, error, sc->sc_carpdev->if_xname);
 872                         carp_demote_adj(V_carp_senderr_adj, msg);
 873                 }
 874                 sc->sc_sendad_success = 0;
 875         } else if (sc->sc_sendad_errors > 0) {
 876                 if (++sc->sc_sendad_success >= CARP_SENDAD_MIN_SUCCESS) {
 877                         if (sc->sc_sendad_errors >= CARP_SENDAD_MAX_ERRORS) {
 878                                 static const char fmt[] = "send ok on %s";
 879                                 char msg[sizeof(fmt) + IFNAMSIZ];
 880
 881                                 sprintf(msg, fmt, sc->sc_carpdev->if_xname);
 882                                 carp_demote_adj(-V_carp_senderr_adj, msg);
 883                         }
 884                         sc->sc_sendad_errors = 0;
 885                 }
 886         }
 887 }
 888
 889 /*
 890  * Pick the best ifaddr on the given ifp for sending CARP
 891  * advertisements.
 892  *
 893  * "Best" here is defined by ifa_preferred().  This function is much
 894  * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
 895  *
 896  * (This could be simplified to return the actual address, except that
 897  * it has a different format in AF_INET and AF_INET6.)
 898  */
 899 static struct ifaddr *
 900 carp_best_ifa(int af, struct ifnet *ifp)
 901 {
 902         struct ifaddr *ifa, *best;
 903
 904         NET_EPOCH_ASSERT();
 905
 906         if (af >= AF_MAX)
 907                 return (NULL);
 908         best = NULL;
 909         CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
 910                 if (ifa->ifa_addr->sa_family == af &&
 911                     (best == NULL || ifa_preferred(best, ifa)))
 912                         best = ifa;
 913         }
 914         if (best != NULL)
 915                 ifa_ref(best);
 916         return (best);
 917 }
 918
 919 static void
 920 carp_send_ad_locked(struct carp_softc *sc)
 921 {
 922         struct carp_header ch;
 923         struct timeval tv;
 924         struct ifaddr *ifa;
 925         struct carp_header *ch_ptr;
 926         struct mbuf *m;
 927         int len, advskew;
 928
 929         NET_EPOCH_ASSERT();
 930         CARP_LOCK_ASSERT(sc);
 931
 932         advskew = DEMOTE_ADVSKEW(sc);
 933         tv.tv_sec = sc->sc_advbase;
 934         tv.tv_usec = advskew * 1000000 / 256;
 935
 936         ch.carp_version = CARP_VERSION;
 937         ch.carp_type = CARP_ADVERTISEMENT;
 938         ch.carp_vhid = sc->sc_vhid;
 939         ch.carp_advbase = sc->sc_advbase;
 940         ch.carp_advskew = advskew;
 941         ch.carp_authlen = 7;    /* XXX DEFINE */
 942         ch.carp_pad1 = 0;       /* must be zero */
 943         ch.carp_cksum = 0;
 944
 945         /* XXXGL: OpenBSD picks first ifaddr with needed family. */
 946
 947 #ifdef INET
 948         if (sc->sc_naddrs) {
 949                 struct ip *ip;
 950
 951                 m = m_gethdr(M_NOWAIT, MT_DATA);
 952                 if (m == NULL) {
 953                         CARPSTATS_INC(carps_onomem);
 954                         goto resched;
 955                 }
 956                 len = sizeof(*ip) + sizeof(ch);
 957                 m->m_pkthdr.len = len;
 958                 m->m_pkthdr.rcvif = NULL;
 959                 m->m_len = len;
 960                 M_ALIGN(m, m->m_len);
 961                 m->m_flags |= M_MCAST;
 962                 ip = mtod(m, struct ip *);
 963                 ip->ip_v = IPVERSION;
 964                 ip->ip_hl = sizeof(*ip) >> 2;
 965                 ip->ip_tos = V_carp_dscp << IPTOS_DSCP_OFFSET;
 966                 ip->ip_len = htons(len);
 967                 ip->ip_off = htons(IP_DF);
 968                 ip->ip_ttl = CARP_DFLTTL;
 969                 ip->ip_p = IPPROTO_CARP;
 970                 ip->ip_sum = 0;
 971                 ip_fillid(ip);
 972
 973                 ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
 974                 if (ifa != NULL) {
 975                         ip->ip_src.s_addr =
 976                             ifatoia(ifa)->ia_addr.sin_addr.s_addr;
 977                         ifa_free(ifa);
 978                 } else
 979                         ip->ip_src.s_addr = 0;
 980                 ip->ip_dst.s_addr = htonl(INADDR_CARP_GROUP);
 981
 982                 ch_ptr = (struct carp_header *)(&ip[1]);
 983                 bcopy(&ch, ch_ptr, sizeof(ch));
 984                 if (carp_prepare_ad(m, sc, ch_ptr))
 985                         goto resched;
 986
 987                 m->m_data += sizeof(*ip);
 988                 ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip));
 989                 m->m_data -= sizeof(*ip);
 990
 991                 CARPSTATS_INC(carps_opackets);
 992
 993                 carp_send_ad_error(sc, ip_output(m, NULL, NULL, IP_RAWOUTPUT,
 994                     &sc->sc_carpdev->if_carp->cif_imo, NULL));
 995         }
 996 #endif /* INET */
 997 #ifdef INET6
 998         if (sc->sc_naddrs6) {
 999                 struct ip6_hdr *ip6;
1000
1001                 m = m_gethdr(M_NOWAIT, MT_DATA);
1002                 if (m == NULL) {
1003                         CARPSTATS_INC(carps_onomem);
1004                         goto resched;
1005                 }
1006                 len = sizeof(*ip6) + sizeof(ch);
1007                 m->m_pkthdr.len = len;
1008                 m->m_pkthdr.rcvif = NULL;
1009                 m->m_len = len;
1010                 M_ALIGN(m, m->m_len);
1011                 m->m_flags |= M_MCAST;
1012                 ip6 = mtod(m, struct ip6_hdr *);
1013                 bzero(ip6, sizeof(*ip6));
1014                 ip6->ip6_vfc |= IPV6_VERSION;
1015                 /* Traffic class isn't defined in ip6 struct instead
1016                  * it gets offset into flowid field */
1017                 ip6->ip6_flow |= htonl(V_carp_dscp << (IPV6_FLOWLABEL_LEN +
1018                     IPTOS_DSCP_OFFSET));
1019                 ip6->ip6_hlim = CARP_DFLTTL;
1020                 ip6->ip6_nxt = IPPROTO_CARP;
1021
1022                 /* set the source address */
1023                 ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
1024                 if (ifa != NULL) {
1025                         bcopy(IFA_IN6(ifa), &ip6->ip6_src,
1026                             sizeof(struct in6_addr));
1027                         ifa_free(ifa);
1028                 } else
1029                         /* This should never happen with IPv6. */
1030                         bzero(&ip6->ip6_src, sizeof(struct in6_addr));
1031
1032                 /* Set the multicast destination. */
1033                 ip6->ip6_dst.s6_addr16[0] = htons(0xff02);
1034                 ip6->ip6_dst.s6_addr8[15] = 0x12;
1035                 if (in6_setscope(&ip6->ip6_dst, sc->sc_carpdev, NULL) != 0) {
1036                         m_freem(m);
1037                         CARP_DEBUG("%s: in6_setscope failed\n", __func__);
1038                         goto resched;
1039                 }
1040
1041                 ch_ptr = (struct carp_header *)(&ip6[1]);
1042                 bcopy(&ch, ch_ptr, sizeof(ch));
1043                 if (carp_prepare_ad(m, sc, ch_ptr))
1044                         goto resched;
1045
1046                 m->m_data += sizeof(*ip6);
1047                 ch_ptr->carp_cksum = in_cksum(m, len - sizeof(*ip6));
1048                 m->m_data -= sizeof(*ip6);
1049
1050                 CARPSTATS_INC(carps_opackets6);
1051
1052                 carp_send_ad_error(sc, ip6_output(m, NULL, NULL, 0,
1053                     &sc->sc_carpdev->if_carp->cif_im6o, NULL, NULL));
1054         }
1055 #endif /* INET6 */
1056
1057 resched:
1058         callout_reset(&sc->sc_ad_tmo, tvtohz(&tv), carp_send_ad, sc);
1059 }
1060
1061 static void
1062 carp_addroute(struct carp_softc *sc)
1063 {
1064         struct ifaddr *ifa;
1065
1066         CARP_FOREACH_IFA(sc, ifa)
1067                 carp_ifa_addroute(ifa);
1068 }
1069
1070 static void
1071 carp_ifa_addroute(struct ifaddr *ifa)
1072 {
1073
1074         switch (ifa->ifa_addr->sa_family) {
1075 #ifdef INET
1076         case AF_INET:
1077                 in_addprefix(ifatoia(ifa));
1078                 ifa_add_loopback_route(ifa,
1079                     (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1080                 break;
1081 #endif
1082 #ifdef INET6
1083         case AF_INET6:
1084                 ifa_add_loopback_route(ifa,
1085                     (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1086                 nd6_add_ifa_lle(ifatoia6(ifa));
1087                 break;
1088 #endif
1089         }
1090 }
1091
1092 static void
1093 carp_delroute(struct carp_softc *sc)
1094 {
1095         struct ifaddr *ifa;
1096
1097         CARP_FOREACH_IFA(sc, ifa)
1098                 carp_ifa_delroute(ifa);
1099 }
1100
1101 static void
1102 carp_ifa_delroute(struct ifaddr *ifa)
1103 {
1104
1105         switch (ifa->ifa_addr->sa_family) {
1106 #ifdef INET
1107         case AF_INET:
1108                 ifa_del_loopback_route(ifa,
1109                     (struct sockaddr *)&ifatoia(ifa)->ia_addr);
1110                 in_scrubprefix(ifatoia(ifa), LLE_STATIC);
1111                 break;
1112 #endif
1113 #ifdef INET6
1114         case AF_INET6:
1115                 ifa_del_loopback_route(ifa,
1116                     (struct sockaddr *)&ifatoia6(ifa)->ia_addr);
1117                 nd6_rem_ifa_lle(ifatoia6(ifa), 1);
1118                 break;
1119 #endif
1120         }
1121 }
1122
1123 int
1124 carp_master(struct ifaddr *ifa)
1125 {
1126         struct carp_softc *sc = ifa->ifa_carp;
1127
1128         return (sc->sc_state == MASTER);
1129 }
1130
1131 #ifdef INET
1132 /*
1133  * Broadcast a gratuitous ARP request containing
1134  * the virtual router MAC address for each IP address
1135  * associated with the virtual router.
1136  */
1137 static void
1138 carp_send_arp(struct carp_softc *sc)
1139 {
1140         struct ifaddr *ifa;
1141         struct in_addr addr;
1142
1143         NET_EPOCH_ASSERT();
1144
1145         CARP_FOREACH_IFA(sc, ifa) {
1146                 if (ifa->ifa_addr->sa_family != AF_INET)
1147                         continue;
1148                 addr = ((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
1149                 arp_announce_ifaddr(sc->sc_carpdev, addr, LLADDR(&sc->sc_addr));
1150         }
1151 }
1152
1153 int
1154 carp_iamatch(struct ifaddr *ifa, uint8_t **enaddr)
1155 {
1156         struct carp_softc *sc = ifa->ifa_carp;
1157
1158         if (sc->sc_state == MASTER) {
1159                 *enaddr = LLADDR(&sc->sc_addr);
1160                 return (1);
1161         }
1162
1163         return (0);
1164 }
1165 #endif
1166
1167 #ifdef INET6
1168 static void
1169 carp_send_na(struct carp_softc *sc)
1170 {
1171         static struct in6_addr mcast = IN6ADDR_LINKLOCAL_ALLNODES_INIT;
1172         struct ifaddr *ifa;
1173         struct in6_addr *in6;
1174
1175         CARP_FOREACH_IFA(sc, ifa) {
1176                 if (ifa->ifa_addr->sa_family != AF_INET6)
1177                         continue;
1178
1179                 in6 = IFA_IN6(ifa);
1180                 nd6_na_output(sc->sc_carpdev, &mcast, in6,
1181                     ND_NA_FLAG_OVERRIDE, 1, NULL);
1182                 DELAY(1000);    /* XXX */
1183         }
1184 }
1185
1186 /*
1187  * Returns ifa in case it's a carp address and it is MASTER, or if the address
1188  * matches and is not a carp address.  Returns NULL otherwise.
1189  */
1190 struct ifaddr *
1191 carp_iamatch6(struct ifnet *ifp, struct in6_addr *taddr)
1192 {
1193         struct ifaddr *ifa;
1194
1195         NET_EPOCH_ASSERT();
1196
1197         ifa = NULL;
1198         CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
1199                 if (ifa->ifa_addr->sa_family != AF_INET6)
1200                         continue;
1201                 if (!IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa)))
1202                         continue;
1203                 if (ifa->ifa_carp && ifa->ifa_carp->sc_state != MASTER)
1204                         ifa = NULL;
1205                 else
1206                         ifa_ref(ifa);
1207                 break;
1208         }
1209
1210         return (ifa);
1211 }
1212
1213 char *
1214 carp_macmatch6(struct ifnet *ifp, struct mbuf *m, const struct in6_addr *taddr)
1215 {
1216         struct ifaddr *ifa;
1217
1218         NET_EPOCH_ASSERT();
1219
1220         IFNET_FOREACH_IFA(ifp, ifa)
1221                 if (ifa->ifa_addr->sa_family == AF_INET6 &&
1222                     IN6_ARE_ADDR_EQUAL(taddr, IFA_IN6(ifa))) {
1223                         struct carp_softc *sc = ifa->ifa_carp;
1224                         struct m_tag *mtag;
1225
1226                         mtag = m_tag_get(PACKET_TAG_CARP,
1227                             sizeof(struct carp_softc *), M_NOWAIT);
1228                         if (mtag == NULL)
1229                                 /* Better a bit than nothing. */
1230                                 return (LLADDR(&sc->sc_addr));
1231
1232                         bcopy(&sc, mtag + 1, sizeof(sc));
1233                         m_tag_prepend(m, mtag);
1234
1235                         return (LLADDR(&sc->sc_addr));
1236                 }
1237
1238         return (NULL);
1239 }
1240 #endif /* INET6 */
1241
1242 int
1243 carp_forus(struct ifnet *ifp, u_char *dhost)
1244 {
1245         struct carp_softc *sc;
1246         uint8_t *ena = dhost;
1247
1248         if (ena[0] || ena[1] || ena[2] != 0x5e || ena[3] || ena[4] != 1)
1249                 return (0);
1250
1251         CIF_LOCK(ifp->if_carp);
1252         IFNET_FOREACH_CARP(ifp, sc) {
1253                 /*
1254                  * CARP_LOCK() is not here, since would protect nothing, but
1255                  * cause deadlock with if_bridge, calling this under its lock.
1256                  */
1257                 if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
1258                     ETHER_ADDR_LEN)) {
1259                         CIF_UNLOCK(ifp->if_carp);
1260                         return (1);
1261                 }
1262         }
1263         CIF_UNLOCK(ifp->if_carp);
1264
1265         return (0);
1266 }
1267
1268 /* Master down timeout event, executed in callout context. */
1269 static void
1270 carp_master_down(void *v)
1271 {
1272         struct carp_softc *sc = v;
1273         struct epoch_tracker et;
1274
1275         NET_EPOCH_ENTER(et);
1276         CARP_LOCK_ASSERT(sc);
1277
1278         CURVNET_SET(sc->sc_carpdev->if_vnet);
1279         if (sc->sc_state == BACKUP) {
1280                 carp_master_down_locked(sc, "master timed out");
1281         }
1282         CURVNET_RESTORE();
1283
1284         CARP_UNLOCK(sc);
1285         NET_EPOCH_EXIT(et);
1286 }
1287
1288 static void
1289 carp_master_down_locked(struct carp_softc *sc, const char *reason)
1290 {
1291
1292         NET_EPOCH_ASSERT();
1293         CARP_LOCK_ASSERT(sc);
1294
1295         switch (sc->sc_state) {
1296         case BACKUP:
1297                 carp_set_state(sc, MASTER, reason);
1298                 carp_send_ad_locked(sc);
1299 #ifdef INET
1300                 carp_send_arp(sc);
1301 #endif
1302 #ifdef INET6
1303                 carp_send_na(sc);
1304 #endif
1305                 carp_setrun(sc, 0);
1306                 carp_addroute(sc);
1307                 break;
1308         case INIT:
1309         case MASTER:
1310 #ifdef INVARIANTS
1311                 panic("carp: VHID %u@%s: master_down event in %s state\n",
1312                     sc->sc_vhid,
1313                     sc->sc_carpdev->if_xname,
1314                     sc->sc_state ? "MASTER" : "INIT");
1315 #endif
1316                 break;
1317         }
1318 }
1319
1320 /*
1321  * When in backup state, af indicates whether to reset the master down timer
1322  * for v4 or v6. If it's set to zero, reset the ones which are already pending.
1323  */
1324 static void
1325 carp_setrun(struct carp_softc *sc, sa_family_t af)
1326 {
1327         struct timeval tv;
1328
1329         CARP_LOCK_ASSERT(sc);
1330
1331         if ((sc->sc_carpdev->if_flags & IFF_UP) == 0 ||
1332             sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
1333             (sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0) ||
1334             !V_carp_allow)
1335                 return;
1336
1337         switch (sc->sc_state) {
1338         case INIT:
1339                 carp_set_state(sc, BACKUP, "initialization complete");
1340                 carp_setrun(sc, 0);
1341                 break;
1342         case BACKUP:
1343                 callout_stop(&sc->sc_ad_tmo);
1344                 tv.tv_sec = 3 * sc->sc_advbase;
1345                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1346                 switch (af) {
1347 #ifdef INET
1348                 case AF_INET:
1349                         callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1350                             carp_master_down, sc);
1351                         break;
1352 #endif
1353 #ifdef INET6
1354                 case AF_INET6:
1355                         callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1356                             carp_master_down, sc);
1357                         break;
1358 #endif
1359                 default:
1360 #ifdef INET
1361                         if (sc->sc_naddrs)
1362                                 callout_reset(&sc->sc_md_tmo, tvtohz(&tv),
1363                                     carp_master_down, sc);
1364 #endif
1365 #ifdef INET6
1366                         if (sc->sc_naddrs6)
1367                                 callout_reset(&sc->sc_md6_tmo, tvtohz(&tv),
1368                                     carp_master_down, sc);
1369 #endif
1370                         break;
1371                 }
1372                 break;
1373         case MASTER:
1374                 tv.tv_sec = sc->sc_advbase;
1375                 tv.tv_usec = sc->sc_advskew * 1000000 / 256;
1376                 callout_reset(&sc->sc_ad_tmo, tvtohz(&tv),
1377                     carp_send_ad, sc);
1378                 break;
1379         }
1380 }
1381
1382 /*
1383  * Setup multicast structures.
1384  */
1385 static int
1386 carp_multicast_setup(struct carp_if *cif, sa_family_t sa)
1387 {
1388         struct ifnet *ifp = cif->cif_ifp;
1389         int error = 0;
1390
1391         switch (sa) {
1392 #ifdef INET
1393         case AF_INET:
1394             {
1395                 struct ip_moptions *imo = &cif->cif_imo;
1396                 struct in_mfilter *imf;
1397                 struct in_addr addr;
1398
1399                 if (ip_mfilter_first(&imo->imo_head) != NULL)
1400                         return (0);
1401
1402                 imf = ip_mfilter_alloc(M_WAITOK, 0, 0);
1403                 ip_mfilter_init(&imo->imo_head);
1404                 imo->imo_multicast_vif = -1;
1405
1406                 addr.s_addr = htonl(INADDR_CARP_GROUP);
1407                 if ((error = in_joingroup(ifp, &addr, NULL,
1408                     &imf->imf_inm)) != 0) {
1409                         ip_mfilter_free(imf);
1410                         break;
1411                 }
1412
1413                 ip_mfilter_insert(&imo->imo_head, imf);
1414                 imo->imo_multicast_ifp = ifp;
1415                 imo->imo_multicast_ttl = CARP_DFLTTL;
1416                 imo->imo_multicast_loop = 0;
1417                 break;
1418            }
1419 #endif
1420 #ifdef INET6
1421         case AF_INET6:
1422             {
1423                 struct ip6_moptions *im6o = &cif->cif_im6o;
1424                 struct in6_mfilter *im6f[2];
1425                 struct in6_addr in6;
1426
1427                 if (ip6_mfilter_first(&im6o->im6o_head))
1428                         return (0);
1429
1430                 im6f[0] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1431                 im6f[1] = ip6_mfilter_alloc(M_WAITOK, 0, 0);
1432
1433                 ip6_mfilter_init(&im6o->im6o_head);
1434                 im6o->im6o_multicast_hlim = CARP_DFLTTL;
1435                 im6o->im6o_multicast_ifp = ifp;
1436
1437                 /* Join IPv6 CARP multicast group. */
1438                 bzero(&in6, sizeof(in6));
1439                 in6.s6_addr16[0] = htons(0xff02);
1440                 in6.s6_addr8[15] = 0x12;
1441                 if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1442                         ip6_mfilter_free(im6f[0]);
1443                         ip6_mfilter_free(im6f[1]);
1444                         break;
1445                 }
1446                 if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[0]->im6f_in6m, 0)) != 0) {
1447                         ip6_mfilter_free(im6f[0]);
1448                         ip6_mfilter_free(im6f[1]);
1449                         break;
1450                 }
1451
1452                 /* Join solicited multicast address. */
1453                 bzero(&in6, sizeof(in6));
1454                 in6.s6_addr16[0] = htons(0xff02);
1455                 in6.s6_addr32[1] = 0;
1456                 in6.s6_addr32[2] = htonl(1);
1457                 in6.s6_addr32[3] = 0;
1458                 in6.s6_addr8[12] = 0xff;
1459
1460                 if ((error = in6_setscope(&in6, ifp, NULL)) != 0) {
1461                         ip6_mfilter_free(im6f[0]);
1462                         ip6_mfilter_free(im6f[1]);
1463                         break;
1464                 }
1465
1466                 if ((error = in6_joingroup(ifp, &in6, NULL, &im6f[1]->im6f_in6m, 0)) != 0) {
1467                         in6_leavegroup(im6f[0]->im6f_in6m, NULL);
1468                         ip6_mfilter_free(im6f[0]);
1469                         ip6_mfilter_free(im6f[1]);
1470                         break;
1471                 }
1472                 ip6_mfilter_insert(&im6o->im6o_head, im6f[0]);
1473                 ip6_mfilter_insert(&im6o->im6o_head, im6f[1]);
1474                 break;
1475             }
1476 #endif
1477         }
1478
1479         return (error);
1480 }
1481
1482 /*
1483  * Free multicast structures.
1484  */
1485 static void
1486 carp_multicast_cleanup(struct carp_if *cif, sa_family_t sa)
1487 {
1488 #ifdef INET
1489         struct ip_moptions *imo = &cif->cif_imo;
1490         struct in_mfilter *imf;
1491 #endif
1492 #ifdef INET6
1493         struct ip6_moptions *im6o = &cif->cif_im6o;
1494         struct in6_mfilter *im6f;
1495 #endif
1496         sx_assert(&carp_sx, SA_XLOCKED);
1497
1498         switch (sa) {
1499 #ifdef INET
1500         case AF_INET:
1501                 if (cif->cif_naddrs != 0)
1502                         break;
1503
1504                 while ((imf = ip_mfilter_first(&imo->imo_head)) != NULL) {
1505                         ip_mfilter_remove(&imo->imo_head, imf);
1506                         in_leavegroup(imf->imf_inm, NULL);
1507                         ip_mfilter_free(imf);
1508                 }
1509                 break;
1510 #endif
1511 #ifdef INET6
1512         case AF_INET6:
1513                 if (cif->cif_naddrs6 != 0)
1514                         break;
1515
1516                 while ((im6f = ip6_mfilter_first(&im6o->im6o_head)) != NULL) {
1517                         ip6_mfilter_remove(&im6o->im6o_head, im6f);
1518                         in6_leavegroup(im6f->im6f_in6m, NULL);
1519                         ip6_mfilter_free(im6f);
1520                 }
1521                 break;
1522 #endif
1523         }
1524 }
1525
1526 int
1527 carp_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa)
1528 {
1529         struct m_tag *mtag;
1530         struct carp_softc *sc;
1531
1532         if (!sa)
1533                 return (0);
1534
1535         switch (sa->sa_family) {
1536 #ifdef INET
1537         case AF_INET:
1538                 break;
1539 #endif
1540 #ifdef INET6
1541         case AF_INET6:
1542                 break;
1543 #endif
1544         default:
1545                 return (0);
1546         }
1547
1548         mtag = m_tag_find(m, PACKET_TAG_CARP, NULL);
1549         if (mtag == NULL)
1550                 return (0);
1551
1552         bcopy(mtag + 1, &sc, sizeof(sc));
1553
1554         /* Set the source MAC address to the Virtual Router MAC Address. */
1555         switch (ifp->if_type) {
1556         case IFT_ETHER:
1557         case IFT_BRIDGE:
1558         case IFT_L2VLAN: {
1559                         struct ether_header *eh;
1560
1561                         eh = mtod(m, struct ether_header *);
1562                         eh->ether_shost[0] = 0;
1563                         eh->ether_shost[1] = 0;
1564                         eh->ether_shost[2] = 0x5e;
1565                         eh->ether_shost[3] = 0;
1566                         eh->ether_shost[4] = 1;
1567                         eh->ether_shost[5] = sc->sc_vhid;
1568                 }
1569                 break;
1570         default:
1571                 printf("%s: carp is not supported for the %d interface type\n",
1572                     ifp->if_xname, ifp->if_type);
1573                 return (EOPNOTSUPP);
1574         }
1575
1576         return (0);
1577 }
1578
1579 static struct carp_softc*
1580 carp_alloc(struct ifnet *ifp)
1581 {
1582         struct carp_softc *sc;
1583         struct carp_if *cif;
1584
1585         sx_assert(&carp_sx, SA_XLOCKED);
1586
1587         if ((cif = ifp->if_carp) == NULL)
1588                 cif = carp_alloc_if(ifp);
1589
1590         sc = malloc(sizeof(*sc), M_CARP, M_WAITOK|M_ZERO);
1591
1592         sc->sc_advbase = CARP_DFLTINTV;
1593         sc->sc_vhid = -1;       /* required setting */
1594         sc->sc_init_counter = 1;
1595         sc->sc_state = INIT;
1596
1597         sc->sc_ifasiz = sizeof(struct ifaddr *);
1598         sc->sc_ifas = malloc(sc->sc_ifasiz, M_CARP, M_WAITOK|M_ZERO);
1599         sc->sc_carpdev = ifp;
1600
1601         CARP_LOCK_INIT(sc);
1602 #ifdef INET
1603         callout_init_mtx(&sc->sc_md_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1604 #endif
1605 #ifdef INET6
1606         callout_init_mtx(&sc->sc_md6_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1607 #endif
1608         callout_init_mtx(&sc->sc_ad_tmo, &sc->sc_mtx, CALLOUT_RETURNUNLOCKED);
1609
1610         CIF_LOCK(cif);
1611         TAILQ_INSERT_TAIL(&cif->cif_vrs, sc, sc_list);
1612         CIF_UNLOCK(cif);
1613
1614         mtx_lock(&carp_mtx);
1615         LIST_INSERT_HEAD(&carp_list, sc, sc_next);
1616         mtx_unlock(&carp_mtx);
1617
1618         return (sc);
1619 }
1620
1621 static void
1622 carp_grow_ifas(struct carp_softc *sc)
1623 {
1624         struct ifaddr **new;
1625
1626         new = malloc(sc->sc_ifasiz * 2, M_CARP, M_WAITOK | M_ZERO);
1627         CARP_LOCK(sc);
1628         bcopy(sc->sc_ifas, new, sc->sc_ifasiz);
1629         free(sc->sc_ifas, M_CARP);
1630         sc->sc_ifas = new;
1631         sc->sc_ifasiz *= 2;
1632         CARP_UNLOCK(sc);
1633 }
1634
1635 static void
1636 carp_destroy(struct carp_softc *sc)
1637 {
1638         struct ifnet *ifp = sc->sc_carpdev;
1639         struct carp_if *cif = ifp->if_carp;
1640
1641         sx_assert(&carp_sx, SA_XLOCKED);
1642
1643         if (sc->sc_suppress)
1644                 carp_demote_adj(-V_carp_ifdown_adj, "vhid removed");
1645         CARP_UNLOCK(sc);
1646
1647         CIF_LOCK(cif);
1648         TAILQ_REMOVE(&cif->cif_vrs, sc, sc_list);
1649         CIF_UNLOCK(cif);
1650
1651         mtx_lock(&carp_mtx);
1652         LIST_REMOVE(sc, sc_next);
1653         mtx_unlock(&carp_mtx);
1654
1655         callout_drain(&sc->sc_ad_tmo);
1656 #ifdef INET
1657         callout_drain(&sc->sc_md_tmo);
1658 #endif
1659 #ifdef INET6
1660         callout_drain(&sc->sc_md6_tmo);
1661 #endif
1662         CARP_LOCK_DESTROY(sc);
1663
1664         free(sc->sc_ifas, M_CARP);
1665         free(sc, M_CARP);
1666 }
1667
1668 static struct carp_if*
1669 carp_alloc_if(struct ifnet *ifp)
1670 {
1671         struct carp_if *cif;
1672         int error;
1673
1674         cif = malloc(sizeof(*cif), M_CARP, M_WAITOK|M_ZERO);
1675
1676         if ((error = ifpromisc(ifp, 1)) != 0)
1677                 printf("%s: ifpromisc(%s) failed: %d\n",
1678                     __func__, ifp->if_xname, error);
1679         else
1680                 cif->cif_flags |= CIF_PROMISC;
1681
1682         CIF_LOCK_INIT(cif);
1683         cif->cif_ifp = ifp;
1684         TAILQ_INIT(&cif->cif_vrs);
1685
1686         IF_ADDR_WLOCK(ifp);
1687         ifp->if_carp = cif;
1688         if_ref(ifp);
1689         IF_ADDR_WUNLOCK(ifp);
1690
1691         return (cif);
1692 }
1693
1694 static void
1695 carp_free_if(struct carp_if *cif)
1696 {
1697         struct ifnet *ifp = cif->cif_ifp;
1698
1699         CIF_LOCK_ASSERT(cif);
1700         KASSERT(TAILQ_EMPTY(&cif->cif_vrs), ("%s: softc list not empty",
1701             __func__));
1702
1703         IF_ADDR_WLOCK(ifp);
1704         ifp->if_carp = NULL;
1705         IF_ADDR_WUNLOCK(ifp);
1706
1707         CIF_LOCK_DESTROY(cif);
1708
1709         if (cif->cif_flags & CIF_PROMISC)
1710                 ifpromisc(ifp, 0);
1711         if_rele(ifp);
1712
1713         free(cif, M_CARP);
1714 }
1715
1716 static void
1717 carp_carprcp(struct carpreq *carpr, struct carp_softc *sc, int priv)
1718 {
1719
1720         CARP_LOCK(sc);
1721         carpr->carpr_state = sc->sc_state;
1722         carpr->carpr_vhid = sc->sc_vhid;
1723         carpr->carpr_advbase = sc->sc_advbase;
1724         carpr->carpr_advskew = sc->sc_advskew;
1725         if (priv)
1726                 bcopy(sc->sc_key, carpr->carpr_key, sizeof(carpr->carpr_key));
1727         else
1728                 bzero(carpr->carpr_key, sizeof(carpr->carpr_key));
1729         CARP_UNLOCK(sc);
1730 }
1731
1732 int
1733 carp_ioctl(struct ifreq *ifr, u_long cmd, struct thread *td)
1734 {
1735         struct carpreq carpr;
1736         struct ifnet *ifp;
1737         struct carp_softc *sc = NULL;
1738         int error = 0, locked = 0;
1739
1740         if ((error = copyin(ifr_data_get_ptr(ifr), &carpr, sizeof carpr)))
1741                 return (error);
1742
1743         ifp = ifunit_ref(ifr->ifr_name);
1744         if (ifp == NULL)
1745                 return (ENXIO);
1746
1747         switch (ifp->if_type) {
1748         case IFT_ETHER:
1749         case IFT_L2VLAN:
1750         case IFT_BRIDGE:
1751                 break;
1752         default:
1753                 error = EOPNOTSUPP;
1754                 goto out;
1755         }
1756
1757         if ((ifp->if_flags & IFF_MULTICAST) == 0) {
1758                 error = EADDRNOTAVAIL;
1759                 goto out;
1760         }
1761
1762         sx_xlock(&carp_sx);
1763         switch (cmd) {
1764         case SIOCSVH:
1765                 if ((error = priv_check(td, PRIV_NETINET_CARP)))
1766                         break;
1767                 if (carpr.carpr_vhid <= 0 || carpr.carpr_vhid > CARP_MAXVHID ||
1768                     carpr.carpr_advbase < 0 || carpr.carpr_advskew < 0) {
1769                         error = EINVAL;
1770                         break;
1771                 }
1772
1773                 if (ifp->if_carp) {
1774                         IFNET_FOREACH_CARP(ifp, sc)
1775                                 if (sc->sc_vhid == carpr.carpr_vhid)
1776                                         break;
1777                 }
1778                 if (sc == NULL) {
1779                         sc = carp_alloc(ifp);
1780                         CARP_LOCK(sc);
1781                         sc->sc_vhid = carpr.carpr_vhid;
1782                         LLADDR(&sc->sc_addr)[0] = 0;
1783                         LLADDR(&sc->sc_addr)[1] = 0;
1784                         LLADDR(&sc->sc_addr)[2] = 0x5e;
1785                         LLADDR(&sc->sc_addr)[3] = 0;
1786                         LLADDR(&sc->sc_addr)[4] = 1;
1787                         LLADDR(&sc->sc_addr)[5] = sc->sc_vhid;
1788                 } else
1789                         CARP_LOCK(sc);
1790                 locked = 1;
1791                 if (carpr.carpr_advbase > 0) {
1792                         if (carpr.carpr_advbase > 255 ||
1793                             carpr.carpr_advbase < CARP_DFLTINTV) {
1794                                 error = EINVAL;
1795                                 break;
1796                         }
1797                         sc->sc_advbase = carpr.carpr_advbase;
1798                 }
1799                 if (carpr.carpr_advskew >= 255) {
1800                         error = EINVAL;
1801                         break;
1802                 }
1803                 sc->sc_advskew = carpr.carpr_advskew;
1804                 if (carpr.carpr_key[0] != '\0') {
1805                         bcopy(carpr.carpr_key, sc->sc_key, sizeof(sc->sc_key));
1806                         carp_hmac_prepare(sc);
1807                 }
1808                 if (sc->sc_state != INIT &&
1809                     carpr.carpr_state != sc->sc_state) {
1810                         switch (carpr.carpr_state) {
1811                         case BACKUP:
1812                                 callout_stop(&sc->sc_ad_tmo);
1813                                 carp_set_state(sc, BACKUP,
1814                                     "user requested via ifconfig");
1815                                 carp_setrun(sc, 0);
1816                                 carp_delroute(sc);
1817                                 break;
1818                         case MASTER:
1819                                 carp_master_down_locked(sc,
1820                                     "user requested via ifconfig");
1821                                 break;
1822                         default:
1823                                 break;
1824                         }
1825                 }
1826                 break;
1827
1828         case SIOCGVH:
1829             {
1830                 int priveleged;
1831
1832                 if (carpr.carpr_vhid < 0 || carpr.carpr_vhid > CARP_MAXVHID) {
1833                         error = EINVAL;
1834                         break;
1835                 }
1836                 if (carpr.carpr_count < 1) {
1837                         error = EMSGSIZE;
1838                         break;
1839                 }
1840                 if (ifp->if_carp == NULL) {
1841                         error = ENOENT;
1842                         break;
1843                 }
1844
1845                 priveleged = (priv_check(td, PRIV_NETINET_CARP) == 0);
1846                 if (carpr.carpr_vhid != 0) {
1847                         IFNET_FOREACH_CARP(ifp, sc)
1848                                 if (sc->sc_vhid == carpr.carpr_vhid)
1849                                         break;
1850                         if (sc == NULL) {
1851                                 error = ENOENT;
1852                                 break;
1853                         }
1854                         carp_carprcp(&carpr, sc, priveleged);
1855                         error = copyout(&carpr, ifr_data_get_ptr(ifr),
1856                             sizeof(carpr));
1857                 } else  {
1858                         int i, count;
1859
1860                         count = 0;
1861                         IFNET_FOREACH_CARP(ifp, sc)
1862                                 count++;
1863
1864                         if (count > carpr.carpr_count) {
1865                                 CIF_UNLOCK(ifp->if_carp);
1866                                 error = EMSGSIZE;
1867                                 break;
1868                         }
1869
1870                         i = 0;
1871                         IFNET_FOREACH_CARP(ifp, sc) {
1872                                 carp_carprcp(&carpr, sc, priveleged);
1873                                 carpr.carpr_count = count;
1874                                 error = copyout(&carpr,
1875                                     (char *)ifr_data_get_ptr(ifr) +
1876                                     (i * sizeof(carpr)), sizeof(carpr));
1877                                 if (error) {
1878                                         CIF_UNLOCK(ifp->if_carp);
1879                                         break;
1880                                 }
1881                                 i++;
1882                         }
1883                 }
1884                 break;
1885             }
1886         default:
1887                 error = EINVAL;
1888         }
1889         sx_xunlock(&carp_sx);
1890
1891 out:
1892         if (locked)
1893                 CARP_UNLOCK(sc);
1894         if_rele(ifp);
1895
1896         return (error);
1897 }
1898
1899 static int
1900 carp_get_vhid(struct ifaddr *ifa)
1901 {
1902
1903         if (ifa == NULL || ifa->ifa_carp == NULL)
1904                 return (0);
1905
1906         return (ifa->ifa_carp->sc_vhid);
1907 }
1908
1909 int
1910 carp_attach(struct ifaddr *ifa, int vhid)
1911 {
1912         struct ifnet *ifp = ifa->ifa_ifp;
1913         struct carp_if *cif = ifp->if_carp;
1914         struct carp_softc *sc;
1915         int index, error;
1916
1917         KASSERT(ifa->ifa_carp == NULL, ("%s: ifa %p attached", __func__, ifa));
1918
1919         switch (ifa->ifa_addr->sa_family) {
1920 #ifdef INET
1921         case AF_INET:
1922 #endif
1923 #ifdef INET6
1924         case AF_INET6:
1925 #endif
1926                 break;
1927         default:
1928                 return (EPROTOTYPE);
1929         }
1930
1931         sx_xlock(&carp_sx);
1932         if (ifp->if_carp == NULL) {
1933                 sx_xunlock(&carp_sx);
1934                 return (ENOPROTOOPT);
1935         }
1936
1937         IFNET_FOREACH_CARP(ifp, sc)
1938                 if (sc->sc_vhid == vhid)
1939                         break;
1940         if (sc == NULL) {
1941                 sx_xunlock(&carp_sx);
1942                 return (ENOENT);
1943         }
1944
1945         error = carp_multicast_setup(cif, ifa->ifa_addr->sa_family);
1946         if (error) {
1947                 CIF_FREE(cif);
1948                 sx_xunlock(&carp_sx);
1949                 return (error);
1950         }
1951
1952         index = sc->sc_naddrs + sc->sc_naddrs6 + 1;
1953         if (index > sc->sc_ifasiz / sizeof(struct ifaddr *))
1954                 carp_grow_ifas(sc);
1955
1956         switch (ifa->ifa_addr->sa_family) {
1957 #ifdef INET
1958         case AF_INET:
1959                 cif->cif_naddrs++;
1960                 sc->sc_naddrs++;
1961                 break;
1962 #endif
1963 #ifdef INET6
1964         case AF_INET6:
1965                 cif->cif_naddrs6++;
1966                 sc->sc_naddrs6++;
1967                 break;
1968 #endif
1969         }
1970
1971         ifa_ref(ifa);
1972
1973         CARP_LOCK(sc);
1974         sc->sc_ifas[index - 1] = ifa;
1975         ifa->ifa_carp = sc;
1976         carp_hmac_prepare(sc);
1977         carp_sc_state(sc);
1978         CARP_UNLOCK(sc);
1979
1980         sx_xunlock(&carp_sx);
1981
1982         return (0);
1983 }
1984
1985 void
1986 carp_detach(struct ifaddr *ifa, bool keep_cif)
1987 {
1988         struct ifnet *ifp = ifa->ifa_ifp;
1989         struct carp_if *cif = ifp->if_carp;
1990         struct carp_softc *sc = ifa->ifa_carp;
1991         int i, index;
1992
1993         KASSERT(sc != NULL, ("%s: %p not attached", __func__, ifa));
1994
1995         sx_xlock(&carp_sx);
1996
1997         CARP_LOCK(sc);
1998         /* Shift array. */
1999         index = sc->sc_naddrs + sc->sc_naddrs6;
2000         for (i = 0; i < index; i++)
2001                 if (sc->sc_ifas[i] == ifa)
2002                         break;
2003         KASSERT(i < index, ("%s: %p no backref", __func__, ifa));
2004         for (; i < index - 1; i++)
2005                 sc->sc_ifas[i] = sc->sc_ifas[i+1];
2006         sc->sc_ifas[index - 1] = NULL;
2007
2008         switch (ifa->ifa_addr->sa_family) {
2009 #ifdef INET
2010         case AF_INET:
2011                 cif->cif_naddrs--;
2012                 sc->sc_naddrs--;
2013                 break;
2014 #endif
2015 #ifdef INET6
2016         case AF_INET6:
2017                 cif->cif_naddrs6--;
2018                 sc->sc_naddrs6--;
2019                 break;
2020 #endif
2021         }
2022
2023         carp_ifa_delroute(ifa);
2024         carp_multicast_cleanup(cif, ifa->ifa_addr->sa_family);
2025
2026         ifa->ifa_carp = NULL;
2027         ifa_free(ifa);
2028
2029         carp_hmac_prepare(sc);
2030         carp_sc_state(sc);
2031
2032         if (!keep_cif && sc->sc_naddrs == 0 && sc->sc_naddrs6 == 0)
2033                 carp_destroy(sc);
2034         else
2035                 CARP_UNLOCK(sc);
2036
2037         if (!keep_cif)
2038                 CIF_FREE(cif);
2039
2040         sx_xunlock(&carp_sx);
2041 }
2042
2043 static void
2044 carp_set_state(struct carp_softc *sc, int state, const char *reason)
2045 {
2046
2047         CARP_LOCK_ASSERT(sc);
2048
2049         if (sc->sc_state != state) {
2050                 const char *carp_states[] = { CARP_STATES };
2051                 char subsys[IFNAMSIZ+5];
2052
2053                 snprintf(subsys, IFNAMSIZ+5, "%u@%s", sc->sc_vhid,
2054                     sc->sc_carpdev->if_xname);
2055
2056                 CARP_LOG("%s: %s -> %s (%s)\n", subsys,
2057                     carp_states[sc->sc_state], carp_states[state], reason);
2058
2059                 sc->sc_state = state;
2060
2061                 devctl_notify("CARP", subsys, carp_states[state], NULL);
2062         }
2063 }
2064
2065 static void
2066 carp_linkstate(struct ifnet *ifp)
2067 {
2068         struct carp_softc *sc;
2069
2070         CIF_LOCK(ifp->if_carp);
2071         IFNET_FOREACH_CARP(ifp, sc) {
2072                 CARP_LOCK(sc);
2073                 carp_sc_state(sc);
2074                 CARP_UNLOCK(sc);
2075         }
2076         CIF_UNLOCK(ifp->if_carp);
2077 }
2078
2079 static void
2080 carp_sc_state(struct carp_softc *sc)
2081 {
2082
2083         CARP_LOCK_ASSERT(sc);
2084
2085         if (sc->sc_carpdev->if_link_state != LINK_STATE_UP ||
2086             !(sc->sc_carpdev->if_flags & IFF_UP) ||
2087             !V_carp_allow) {
2088                 callout_stop(&sc->sc_ad_tmo);
2089 #ifdef INET
2090                 callout_stop(&sc->sc_md_tmo);
2091 #endif
2092 #ifdef INET6
2093                 callout_stop(&sc->sc_md6_tmo);
2094 #endif
2095                 carp_set_state(sc, INIT, "hardware interface down");
2096                 carp_setrun(sc, 0);
2097                 if (!sc->sc_suppress)
2098                         carp_demote_adj(V_carp_ifdown_adj, "interface down");
2099                 sc->sc_suppress = 1;
2100         } else {
2101                 carp_set_state(sc, INIT, "hardware interface up");
2102                 carp_setrun(sc, 0);
2103                 if (sc->sc_suppress)
2104                         carp_demote_adj(-V_carp_ifdown_adj, "interface up");
2105                 sc->sc_suppress = 0;
2106         }
2107 }
2108
2109 static void
2110 carp_demote_adj(int adj, char *reason)
2111 {
2112         atomic_add_int(&V_carp_demotion, adj);
2113         CARP_LOG("demoted by %d to %d (%s)\n", adj, V_carp_demotion, reason);
2114         taskqueue_enqueue(taskqueue_swi, &carp_sendall_task);
2115 }
2116
2117 static int
2118 carp_allow_sysctl(SYSCTL_HANDLER_ARGS)
2119 {
2120         int new, error;
2121         struct carp_softc *sc;
2122
2123         new = V_carp_allow;
2124         error = sysctl_handle_int(oidp, &new, 0, req);
2125         if (error || !req->newptr)
2126                 return (error);
2127
2128         if (V_carp_allow != new) {
2129                 V_carp_allow = new;
2130
2131                 mtx_lock(&carp_mtx);
2132                 LIST_FOREACH(sc, &carp_list, sc_next) {
2133                         CARP_LOCK(sc);
2134                         if (curvnet == sc->sc_carpdev->if_vnet)
2135                                 carp_sc_state(sc);
2136                         CARP_UNLOCK(sc);
2137                 }
2138                 mtx_unlock(&carp_mtx);
2139         }
2140
2141         return (0);
2142 }
2143
2144 static int
2145 carp_dscp_sysctl(SYSCTL_HANDLER_ARGS)
2146 {
2147         int new, error;
2148
2149         new = V_carp_dscp;
2150         error = sysctl_handle_int(oidp, &new, 0, req);
2151         if (error || !req->newptr)
2152                 return (error);
2153
2154         if (new < 0 || new > 63)
2155                 return (EINVAL);
2156
2157         V_carp_dscp = new;
2158
2159         return (0);
2160 }
2161
2162 static int
2163 carp_demote_adj_sysctl(SYSCTL_HANDLER_ARGS)
2164 {
2165         int new, error;
2166
2167         new = V_carp_demotion;
2168         error = sysctl_handle_int(oidp, &new, 0, req);
2169         if (error || !req->newptr)
2170                 return (error);
2171
2172         carp_demote_adj(new, "sysctl");
2173
2174         return (0);
2175 }
2176
2177 #ifdef INET
2178 extern  struct domain inetdomain;
2179 static struct protosw in_carp_protosw = {
2180         .pr_type =              SOCK_RAW,
2181         .pr_domain =            &inetdomain,
2182         .pr_protocol =          IPPROTO_CARP,
2183         .pr_flags =             PR_ATOMIC|PR_ADDR,
2184         .pr_input =             carp_input,
2185         .pr_output =            rip_output,
2186         .pr_ctloutput =         rip_ctloutput,
2187         .pr_usrreqs =           &rip_usrreqs
2188 };
2189 #endif
2190
2191 #ifdef INET6
2192 extern  struct domain inet6domain;
2193 static struct protosw in6_carp_protosw = {
2194         .pr_type =              SOCK_RAW,
2195         .pr_domain =            &inet6domain,
2196         .pr_protocol =          IPPROTO_CARP,
2197         .pr_flags =             PR_ATOMIC|PR_ADDR,
2198         .pr_input =             carp6_input,
2199         .pr_output =            rip6_output,
2200         .pr_ctloutput =         rip6_ctloutput,
2201         .pr_usrreqs =           &rip6_usrreqs
2202 };
2203 #endif
2204
2205 static void
2206 carp_mod_cleanup(void)
2207 {
2208
2209 #ifdef INET
2210         if (proto_reg[CARP_INET] == 0) {
2211                 (void)ipproto_unregister(IPPROTO_CARP);
2212                 pf_proto_unregister(PF_INET, IPPROTO_CARP, SOCK_RAW);
2213                 proto_reg[CARP_INET] = -1;
2214         }
2215         carp_iamatch_p = NULL;
2216 #endif
2217 #ifdef INET6
2218         if (proto_reg[CARP_INET6] == 0) {
2219                 (void)ip6proto_unregister(IPPROTO_CARP);
2220                 pf_proto_unregister(PF_INET6, IPPROTO_CARP, SOCK_RAW);
2221                 proto_reg[CARP_INET6] = -1;
2222         }
2223         carp_iamatch6_p = NULL;
2224         carp_macmatch6_p = NULL;
2225 #endif
2226         carp_ioctl_p = NULL;
2227         carp_attach_p = NULL;
2228         carp_detach_p = NULL;
2229         carp_get_vhid_p = NULL;
2230         carp_linkstate_p = NULL;
2231         carp_forus_p = NULL;
2232         carp_output_p = NULL;
2233         carp_demote_adj_p = NULL;
2234         carp_master_p = NULL;
2235         mtx_unlock(&carp_mtx);
2236         taskqueue_drain(taskqueue_swi, &carp_sendall_task);
2237         mtx_destroy(&carp_mtx);
2238         sx_destroy(&carp_sx);
2239 }
2240
2241 static int
2242 carp_mod_load(void)
2243 {
2244         int err;
2245
2246         mtx_init(&carp_mtx, "carp_mtx", NULL, MTX_DEF);
2247         sx_init(&carp_sx, "carp_sx");
2248         LIST_INIT(&carp_list);
2249         carp_get_vhid_p = carp_get_vhid;
2250         carp_forus_p = carp_forus;
2251         carp_output_p = carp_output;
2252         carp_linkstate_p = carp_linkstate;
2253         carp_ioctl_p = carp_ioctl;
2254         carp_attach_p = carp_attach;
2255         carp_detach_p = carp_detach;
2256         carp_demote_adj_p = carp_demote_adj;
2257         carp_master_p = carp_master;
2258 #ifdef INET6
2259         carp_iamatch6_p = carp_iamatch6;
2260         carp_macmatch6_p = carp_macmatch6;
2261         proto_reg[CARP_INET6] = pf_proto_register(PF_INET6,
2262             (struct protosw *)&in6_carp_protosw);
2263         if (proto_reg[CARP_INET6]) {
2264                 printf("carp: error %d attaching to PF_INET6\n",
2265                     proto_reg[CARP_INET6]);
2266                 carp_mod_cleanup();
2267                 return (proto_reg[CARP_INET6]);
2268         }
2269         err = ip6proto_register(IPPROTO_CARP);
2270         if (err) {
2271                 printf("carp: error %d registering with INET6\n", err);
2272                 carp_mod_cleanup();
2273                 return (err);
2274         }
2275 #endif
2276 #ifdef INET
2277         carp_iamatch_p = carp_iamatch;
2278         proto_reg[CARP_INET] = pf_proto_register(PF_INET, &in_carp_protosw);
2279         if (proto_reg[CARP_INET]) {
2280                 printf("carp: error %d attaching to PF_INET\n",
2281                     proto_reg[CARP_INET]);
2282                 carp_mod_cleanup();
2283                 return (proto_reg[CARP_INET]);
2284         }
2285         err = ipproto_register(IPPROTO_CARP);
2286         if (err) {
2287                 printf("carp: error %d registering with INET\n", err);
2288                 carp_mod_cleanup();
2289                 return (err);
2290         }
2291 #endif
2292         return (0);
2293 }
2294
2295 static int
2296 carp_modevent(module_t mod, int type, void *data)
2297 {
2298         switch (type) {
2299         case MOD_LOAD:
2300                 return carp_mod_load();
2301                 /* NOTREACHED */
2302         case MOD_UNLOAD:
2303                 mtx_lock(&carp_mtx);
2304                 if (LIST_EMPTY(&carp_list))
2305                         carp_mod_cleanup();
2306                 else {
2307                         mtx_unlock(&carp_mtx);
2308                         return (EBUSY);
2309                 }
2310                 break;
2311
2312         default:
2313                 return (EINVAL);
2314         }
2315
2316         return (0);
2317 }
2318
2319 static moduledata_t carp_mod = {
2320         "carp",
2321         carp_modevent,
2322         0
2323 };
2324
2325 DECLARE_MODULE(carp, carp_mod, SI_SUB_PROTO_DOMAIN, SI_ORDER_ANY);