sbin/routed/if.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgment:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * $FreeBSD: src/sbin/routed/if.c,v 1.6.2.1 2000/08/14 17:00:03 sheldonh Exp $
  34  * $DragonFly: src/sbin/routed/if.c,v 1.5 2005/03/16 21:21:34 cpressey Exp $
  35  */
  36
  37 #include "defs.h"
  38 #include "pathnames.h"
  39
  40 #if !defined(sgi) && !defined(__NetBSD__)
  41 static char sccsid[] __attribute__((unused)) = "@(#)if.c        8.1 (Berkeley) 6/5/93";
  42 #elif defined(__NetBSD__)
  43 #include <sys/cdefs.h>
  44 __RCSID("$NetBSD$");
  45 #endif
  46 #ident "$FreeBSD: src/sbin/routed/if.c,v 1.6.2.1 2000/08/14 17:00:03 sheldonh Exp $"
  47
  48 struct interface *ifnet;                /* all interfaces */
  49
  50 /* hash table for all interfaces, big enough to tolerate ridiculous
  51  * numbers of IP aliases.  Crazy numbers of aliases such as 7000
  52  * still will not do well, but not just in looking up interfaces
  53  * by name or address.
  54  */
  55 #define AHASH_LEN 211                   /* must be prime */
  56 #define AHASH(a) &ahash_tbl[(a)%AHASH_LEN]
  57 struct interface *ahash_tbl[AHASH_LEN];
  58
  59 #define BHASH_LEN 211                   /* must be prime */
  60 #define BHASH(a) &bhash_tbl[(a)%BHASH_LEN]
  61 struct interface *bhash_tbl[BHASH_LEN];
  62
  63 struct interface *remote_if;            /* remote interfaces */
  64
  65 /* hash for physical interface names.
  66  * Assume there are never more 100 or 200 real interfaces, and that
  67  * aliases are put on the end of the hash chains.
  68  */
  69 #define NHASH_LEN 97
  70 struct interface *nhash_tbl[NHASH_LEN];
  71
  72 int     tot_interfaces;                 /* # of remote and local interfaces */
  73 int     rip_interfaces;                 /* # of interfaces doing RIP */
  74 int     foundloopback;                  /* valid flag for loopaddr */
  75 naddr   loopaddr;                       /* our address on loopback */
  76 struct  rt_spare loop_rts;
  77
  78 struct timeval ifinit_timer;
  79 static struct timeval last_ifinit;
  80 #define IF_RESCAN_DELAY() (last_ifinit.tv_sec == now.tv_sec             \
  81                            && last_ifinit.tv_usec == now.tv_usec        \
  82                            && timercmp(&ifinit_timer, &now, >))
  83
  84 int     have_ripv1_out;                 /* have a RIPv1 interface */
  85 int     have_ripv1_in;
  86
  87
  88 static struct interface**
  89 nhash(char *p)
  90 {
  91         u_int i;
  92
  93         for (i = 0; *p != '\0'; p++) {
  94                 i = ((i<<1) & 0x7fffffff) | ((i>>31) & 1);
  95                 i ^= *p;
  96         }
  97         return &nhash_tbl[i % NHASH_LEN];
  98 }
  99
 100
 101 /* Link a new interface into the lists and hash tables.
 102  */
 103 void
 104 if_link(struct interface *ifp)
 105 {
 106         struct interface **hifp;
 107
 108         ifp->int_prev = &ifnet;
 109         ifp->int_next = ifnet;
 110         if (ifnet != 0)
 111                 ifnet->int_prev = &ifp->int_next;
 112         ifnet = ifp;
 113
 114         hifp = AHASH(ifp->int_addr);
 115         ifp->int_ahash_prev = hifp;
 116         if ((ifp->int_ahash = *hifp) != 0)
 117                 (*hifp)->int_ahash_prev = &ifp->int_ahash;
 118         *hifp = ifp;
 119
 120         if (ifp->int_if_flags & IFF_BROADCAST) {
 121                 hifp = BHASH(ifp->int_brdaddr);
 122                 ifp->int_bhash_prev = hifp;
 123                 if ((ifp->int_bhash = *hifp) != 0)
 124                         (*hifp)->int_bhash_prev = &ifp->int_bhash;
 125                 *hifp = ifp;
 126         }
 127
 128         if (ifp->int_state & IS_REMOTE) {
 129                 ifp->int_rlink_prev = &remote_if;
 130                 ifp->int_rlink = remote_if;
 131                 if (remote_if != 0)
 132                         remote_if->int_rlink_prev = &ifp->int_rlink;
 133                 remote_if = ifp;
 134         }
 135
 136         hifp = nhash(ifp->int_name);
 137         if (ifp->int_state & IS_ALIAS) {
 138                 /* put aliases on the end of the hash chain */
 139                 while (*hifp != 0)
 140                         hifp = &(*hifp)->int_nhash;
 141         }
 142         ifp->int_nhash_prev = hifp;
 143         if ((ifp->int_nhash = *hifp) != 0)
 144                 (*hifp)->int_nhash_prev = &ifp->int_nhash;
 145         *hifp = ifp;
 146 }
 147
 148
 149 /* Find the interface with an address
 150  */
 151 struct interface *
 152 ifwithaddr(naddr addr,
 153            int  bcast,                  /* notice IFF_BROADCAST address */
 154            int  remote)                 /* include IS_REMOTE interfaces */
 155 {
 156         struct interface *ifp, *possible = 0;
 157
 158         remote = (remote == 0) ? IS_REMOTE : 0;
 159
 160         for (ifp = *AHASH(addr); ifp; ifp = ifp->int_ahash) {
 161                 if (ifp->int_addr != addr)
 162                         continue;
 163                 if ((ifp->int_state & remote) != 0)
 164                         continue;
 165                 if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
 166                         return ifp;
 167                 possible = ifp;
 168         }
 169
 170         if (possible || !bcast)
 171                 return possible;
 172
 173         for (ifp = *BHASH(addr); ifp; ifp = ifp->int_bhash) {
 174                 if (ifp->int_brdaddr != addr)
 175                         continue;
 176                 if ((ifp->int_state & remote) != 0)
 177                         continue;
 178                 if ((ifp->int_state & (IS_BROKE | IS_PASSIVE)) == 0)
 179                         return ifp;
 180                 possible = ifp;
 181         }
 182
 183         return possible;
 184 }
 185
 186
 187 /* find the interface with a name
 188  */
 189 struct interface *
 190 ifwithname(char *name,                  /* "ec0" or whatever */
 191            naddr addr)                  /* 0 or network address */
 192 {
 193         struct interface *ifp;
 194
 195         for (;;) {
 196                 for (ifp = *nhash(name); ifp != 0; ifp = ifp->int_nhash) {
 197                         /* If the network address is not specified,
 198                          * ignore any alias interfaces.  Otherwise, look
 199                          * for the interface with the target name and address.
 200                          */
 201                         if (!strcmp(ifp->int_name, name)
 202                             && ((addr == 0 && !(ifp->int_state & IS_ALIAS))
 203                                 || (ifp->int_addr == addr)))
 204                                 return ifp;
 205                 }
 206
 207                 /* If there is no known interface, maybe there is a
 208                  * new interface.  So just once look for new interfaces.
 209                  */
 210                 if (IF_RESCAN_DELAY())
 211                         return 0;
 212                 ifinit();
 213         }
 214 }
 215
 216
 217 struct interface *
 218 ifwithindex(u_short idx, int rescan_ok)
 219 {
 220         struct interface *ifp;
 221
 222         for (;;) {
 223                 for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
 224                         if (ifp->int_index == idx)
 225                                 return ifp;
 226                 }
 227
 228                 /* If there is no known interface, maybe there is a
 229                  * new interface.  So just once look for new interfaces.
 230                  */
 231                 if (!rescan_ok
 232                     || IF_RESCAN_DELAY())
 233                         return 0;
 234                 ifinit();
 235         }
 236 }
 237
 238
 239 /* Find an interface from which the specified address
 240  * should have come from.  Used for figuring out which
 241  * interface a packet came in on.
 242  */
 243 struct interface *
 244 iflookup(naddr addr)
 245 {
 246         struct interface *ifp, *maybe;
 247
 248         maybe = 0;
 249         for (;;) {
 250                 for (ifp = ifnet; ifp; ifp = ifp->int_next) {
 251                         if (ifp->int_if_flags & IFF_POINTOPOINT) {
 252                                 /* finished with a match */
 253                                 if (ifp->int_dstaddr == addr)
 254                                         return ifp;
 255
 256                         } else {
 257                                 /* finished with an exact match */
 258                                 if (ifp->int_addr == addr)
 259                                         return ifp;
 260
 261                                 /* Look for the longest approximate match.
 262                                  */
 263                                 if (on_net(addr, ifp->int_net, ifp->int_mask)
 264                                     && (maybe == 0
 265                                         || ifp->int_mask > maybe->int_mask))
 266                                         maybe = ifp;
 267                         }
 268                 }
 269
 270                 if (maybe != 0
 271                     || IF_RESCAN_DELAY())
 272                         return maybe;
 273
 274                 /* If there is no known interface, maybe there is a
 275                  * new interface.  So just once look for new interfaces.
 276                  */
 277                 ifinit();
 278         }
 279 }
 280
 281
 282 /* Return the classical netmask for an IP address.
 283  */
 284 naddr                                   /* host byte order */
 285 std_mask(naddr addr)                    /* network byte order */
 286 {
 287         addr = ntohl(addr);             /* was a host, not a network */
 288
 289         if (addr == 0)                  /* default route has mask 0 */
 290                 return 0;
 291         if (IN_CLASSA(addr))
 292                 return IN_CLASSA_NET;
 293         if (IN_CLASSB(addr))
 294                 return IN_CLASSB_NET;
 295         return IN_CLASSC_NET;
 296 }
 297
 298
 299 /* Find the netmask that would be inferred by RIPv1 listeners
 300  *      on the given interface for a given network.
 301  *      If no interface is specified, look for the best fitting interface.
 302  */
 303 naddr
 304 ripv1_mask_net(naddr addr,              /* in network byte order */
 305                struct interface *ifp)   /* as seen on this interface */
 306 {
 307         struct r1net *r1p;
 308         naddr mask = 0;
 309
 310         if (addr == 0)                  /* default always has 0 mask */
 311                 return mask;
 312
 313         if (ifp != 0 && ifp->int_ripv1_mask != HOST_MASK) {
 314                 /* If the target network is that of the associated interface
 315                  * on which it arrived, then use the netmask of the interface.
 316                  */
 317                 if (on_net(addr, ifp->int_net, ifp->int_std_mask))
 318                         mask = ifp->int_ripv1_mask;
 319
 320         } else {
 321                 /* Examine all interfaces, and if it the target seems
 322                  * to have the same network number of an interface, use the
 323                  * netmask of that interface.  If there is more than one
 324                  * such interface, prefer the interface with the longest
 325                  * match.
 326                  */
 327                 for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
 328                         if (on_net(addr, ifp->int_std_net, ifp->int_std_mask)
 329                             && ifp->int_ripv1_mask > mask
 330                             && ifp->int_ripv1_mask != HOST_MASK)
 331                                 mask = ifp->int_ripv1_mask;
 332                 }
 333
 334         }
 335
 336         /* check special definitions */
 337         if (mask == 0) {
 338                 for (r1p = r1nets; r1p != 0; r1p = r1p->r1net_next) {
 339                         if (on_net(addr, r1p->r1net_net, r1p->r1net_match)
 340                             && r1p->r1net_mask > mask)
 341                                 mask = r1p->r1net_mask;
 342                 }
 343
 344                 /* Otherwise, make the classic A/B/C guess.
 345                  */
 346                 if (mask == 0)
 347                         mask = std_mask(addr);
 348         }
 349
 350         return mask;
 351 }
 352
 353
 354 naddr
 355 ripv1_mask_host(naddr addr,             /* in network byte order */
 356                 struct interface *ifp)  /* as seen on this interface */
 357 {
 358         naddr mask = ripv1_mask_net(addr, ifp);
 359
 360
 361         /* If the computed netmask does not mask the address,
 362          * then assume it is a host address
 363          */
 364         if ((ntohl(addr) & ~mask) != 0)
 365                 mask = HOST_MASK;
 366         return mask;
 367 }
 368
 369
 370 /* See if a IP address looks reasonable as a destination
 371  */
 372 int                                     /* 0=bad */
 373 check_dst(naddr addr)
 374 {
 375         addr = ntohl(addr);
 376
 377         if (IN_CLASSA(addr)) {
 378                 if (addr == 0)
 379                         return 1;       /* default */
 380
 381                 addr >>= IN_CLASSA_NSHIFT;
 382                 return (addr != 0 && addr != IN_LOOPBACKNET);
 383         }
 384
 385         return (IN_CLASSB(addr) || IN_CLASSC(addr));
 386 }
 387
 388
 389 /* See a new interface duplicates an existing interface.
 390  */
 391 struct interface *
 392 check_dup(naddr addr,                   /* IP address, so network byte order */
 393           naddr dstaddr,                /* ditto */
 394           naddr mask,                   /* mask, so host byte order */
 395           int if_flags)
 396 {
 397         struct interface *ifp;
 398
 399         for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next) {
 400                 if (ifp->int_mask != mask)
 401                         continue;
 402
 403                 if (!iff_up(ifp->int_if_flags))
 404                         continue;
 405
 406                 /* The local address can only be shared with a point-to-point
 407                  * link.
 408                  */
 409                 if (ifp->int_addr == addr
 410                     && (((if_flags|ifp->int_if_flags) & IFF_POINTOPOINT) == 0))
 411                         return ifp;
 412
 413                 if (on_net(ifp->int_dstaddr, ntohl(dstaddr),mask))
 414                         return ifp;
 415         }
 416         return 0;
 417 }
 418
 419
 420 /* See that a remote gateway is reachable.
 421  *      Note that the answer can change as real interfaces come and go.
 422  */
 423 int                                     /* 0=bad */
 424 check_remote(struct interface *ifp)
 425 {
 426         struct rt_entry *rt;
 427
 428         /* do not worry about other kinds */
 429         if (!(ifp->int_state & IS_REMOTE))
 430             return 1;
 431
 432         rt = rtfind(ifp->int_addr);
 433         if (rt != 0
 434             && rt->rt_ifp != 0
 435             &&on_net(ifp->int_addr,
 436                      rt->rt_ifp->int_net, rt->rt_ifp->int_mask))
 437                 return 1;
 438
 439         /* the gateway cannot be reached directly from one of our
 440          * interfaces
 441          */
 442         if (!(ifp->int_state & IS_BROKE)) {
 443                 msglog("unreachable gateway %s in "_PATH_GATEWAYS,
 444                        naddr_ntoa(ifp->int_addr));
 445                 if_bad(ifp);
 446         }
 447         return 0;
 448 }
 449
 450
 451 /* Delete an interface.
 452  */
 453 static void
 454 ifdel(struct interface *ifp)
 455 {
 456         struct ip_mreq m;
 457         struct interface *ifp1;
 458
 459
 460         trace_if("Del", ifp);
 461
 462         ifp->int_state |= IS_BROKE;
 463
 464         /* unlink the interface
 465          */
 466         *ifp->int_prev = ifp->int_next;
 467         if (ifp->int_next != 0)
 468                 ifp->int_next->int_prev = ifp->int_prev;
 469         *ifp->int_ahash_prev = ifp->int_ahash;
 470         if (ifp->int_ahash != 0)
 471                 ifp->int_ahash->int_ahash_prev = ifp->int_ahash_prev;
 472         *ifp->int_nhash_prev = ifp->int_nhash;
 473         if (ifp->int_nhash != 0)
 474                 ifp->int_nhash->int_nhash_prev = ifp->int_nhash_prev;
 475         if (ifp->int_if_flags & IFF_BROADCAST) {
 476                 *ifp->int_bhash_prev = ifp->int_bhash;
 477                 if (ifp->int_bhash != 0)
 478                         ifp->int_bhash->int_bhash_prev = ifp->int_bhash_prev;
 479         }
 480         if (ifp->int_state & IS_REMOTE) {
 481                 *ifp->int_rlink_prev = ifp->int_rlink;
 482                 if (ifp->int_rlink != 0)
 483                         ifp->int_rlink->int_rlink_prev = ifp->int_rlink_prev;
 484         }
 485
 486         if (!(ifp->int_state & IS_ALIAS)) {
 487                 /* delete aliases when the main interface dies
 488                  */
 489                 for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
 490                         if (ifp1 != ifp
 491                             && !strcmp(ifp->int_name, ifp1->int_name))
 492                                 ifdel(ifp1);
 493                 }
 494
 495                 if ((ifp->int_if_flags & IFF_MULTICAST)
 496 #ifdef MCAST_PPP_BUG
 497                     && !(ifp->int_if_flags & IFF_POINTOPOINT)
 498 #endif
 499                     && rip_sock >= 0) {
 500                         m.imr_multiaddr.s_addr = htonl(INADDR_RIP_GROUP);
 501                         m.imr_interface.s_addr = ((ifp->int_if_flags
 502                                                    & IFF_POINTOPOINT)
 503                                                   ? ifp->int_dstaddr
 504                                                   : ifp->int_addr);
 505                         if (setsockopt(rip_sock,IPPROTO_IP,IP_DROP_MEMBERSHIP,
 506                                        &m, sizeof(m)) < 0
 507                             && errno != EADDRNOTAVAIL
 508                             && !TRACEACTIONS)
 509                                 LOGERR("setsockopt(IP_DROP_MEMBERSHIP RIP)");
 510                         if (rip_sock_mcast == ifp)
 511                                 rip_sock_mcast = 0;
 512                 }
 513                 if (ifp->int_rip_sock >= 0) {
 514                         close(ifp->int_rip_sock);
 515                         ifp->int_rip_sock = -1;
 516                         fix_select();
 517                 }
 518
 519                 tot_interfaces--;
 520                 if (!IS_RIP_OFF(ifp->int_state))
 521                         rip_interfaces--;
 522
 523                 /* Zap all routes associated with this interface.
 524                  * Assume routes just using gateways beyond this interface
 525                  * will timeout naturally, and have probably already died.
 526                  */
 527                 rn_walktree(rhead, walk_bad, 0);
 528
 529                 set_rdisc_mg(ifp, 0);
 530                 if_bad_rdisc(ifp);
 531         }
 532
 533         free(ifp);
 534 }
 535
 536
 537 /* Mark an interface ill.
 538  */
 539 void
 540 if_sick(struct interface *ifp)
 541 {
 542         if (0 == (ifp->int_state & (IS_SICK | IS_BROKE))) {
 543                 ifp->int_state |= IS_SICK;
 544                 ifp->int_act_time = NEVER;
 545                 trace_if("Chg", ifp);
 546
 547                 LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
 548         }
 549 }
 550
 551
 552 /* Mark an interface dead.
 553  */
 554 void
 555 if_bad(struct interface *ifp)
 556 {
 557         struct interface *ifp1;
 558
 559
 560         if (ifp->int_state & IS_BROKE)
 561                 return;
 562
 563         LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
 564
 565         ifp->int_state |= (IS_BROKE | IS_SICK);
 566         ifp->int_act_time = NEVER;
 567         ifp->int_query_time = NEVER;
 568         ifp->int_data.ts = now.tv_sec;
 569
 570         trace_if("Chg", ifp);
 571
 572         if (!(ifp->int_state & IS_ALIAS)) {
 573                 for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
 574                         if (ifp1 != ifp
 575                             && !strcmp(ifp->int_name, ifp1->int_name))
 576                                 if_bad(ifp1);
 577                 }
 578                 rn_walktree(rhead, walk_bad, 0);
 579                 if_bad_rdisc(ifp);
 580         }
 581 }
 582
 583
 584 /* Mark an interface alive
 585  */
 586 int                                     /* 1=it was dead */
 587 if_ok(struct interface *ifp,
 588       const char *type)
 589 {
 590         struct interface *ifp1;
 591
 592
 593         if (!(ifp->int_state & IS_BROKE)) {
 594                 if (ifp->int_state & IS_SICK) {
 595                         trace_act("%sinterface %s to %s working better",
 596                                   type,
 597                                   ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
 598                         ifp->int_state &= ~IS_SICK;
 599                 }
 600                 return 0;
 601         }
 602
 603         msglog("%sinterface %s to %s restored",
 604                type, ifp->int_name, naddr_ntoa(ifp->int_dstaddr));
 605         ifp->int_state &= ~(IS_BROKE | IS_SICK);
 606         ifp->int_data.ts = 0;
 607
 608         if (!(ifp->int_state & IS_ALIAS)) {
 609                 for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
 610                         if (ifp1 != ifp
 611                             && !strcmp(ifp->int_name, ifp1->int_name))
 612                                 if_ok(ifp1, type);
 613                 }
 614                 if_ok_rdisc(ifp);
 615         }
 616
 617         if (ifp->int_state & IS_REMOTE) {
 618                 if (!addrouteforif(ifp))
 619                         return 0;
 620         }
 621         return 1;
 622 }
 623
 624
 625 /* disassemble routing message
 626  */
 627 void
 628 rt_xaddrs(struct rt_addrinfo *info,
 629           struct sockaddr *sa,
 630           struct sockaddr *lim,
 631           int addrs)
 632 {
 633         int i;
 634 #ifdef _HAVE_SA_LEN
 635         static struct sockaddr sa_zero;
 636 #endif
 637 #ifdef sgi
 638 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(__uint64_t) - 1))) \
 639                     : sizeof(__uint64_t))
 640 #else
 641 #define ROUNDUP(a) ((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) \
 642                     : sizeof(long))
 643 #endif
 644
 645
 646         memset(info, 0, sizeof(*info));
 647         info->rti_addrs = addrs;
 648         for (i = 0; i < RTAX_MAX && sa < lim; i++) {
 649                 if ((addrs & (1 << i)) == 0)
 650                         continue;
 651 #ifdef _HAVE_SA_LEN
 652                 info->rti_info[i] = (sa->sa_len != 0) ? sa : &sa_zero;
 653                 sa = (struct sockaddr *)((char*)(sa)
 654                                          + ROUNDUP(sa->sa_len));
 655 #else
 656                 info->rti_info[i] = sa;
 657                 sa = (struct sockaddr *)((char*)(sa)
 658                                          + ROUNDUP(_FAKE_SA_LEN_DST(sa)));
 659 #endif
 660         }
 661 }
 662
 663
 664 /* Find the network interfaces which have configured themselves.
 665  *      This must be done regularly, if only for extra addresses
 666  *      that come and go on interfaces.
 667  */
 668 void
 669 ifinit(void)
 670 {
 671         static char *sysctl_buf;
 672         static size_t sysctl_buf_size = 0;
 673         uint complaints = 0;
 674         static u_int prev_complaints = 0;
 675 #       define COMP_NOT_INET    0x001
 676 #       define COMP_NOADDR      0x002
 677 #       define COMP_BADADDR     0x004
 678 #       define COMP_NODST       0x008
 679 #       define COMP_NOBADR      0x010
 680 #       define COMP_NOMASK      0x020
 681 #       define COMP_DUP         0x040
 682 #       define COMP_BAD_METRIC  0x080
 683 #       define COMP_NETMASK     0x100
 684
 685         struct interface ifs, ifs0, *ifp, *ifp1;
 686         struct rt_entry *rt;
 687         size_t needed;
 688         int mib[6];
 689         struct if_msghdr *ifm;
 690         struct ifa_msghdr *ifam, *ifam_lim, *ifam2;
 691         int in, ierr, out, oerr;
 692         struct intnet *intnetp;
 693         struct rt_addrinfo info;
 694 #ifdef SIOCGIFMETRIC
 695         struct ifreq ifr;
 696 #endif
 697
 698
 699         last_ifinit = now;
 700         ifinit_timer.tv_sec = now.tv_sec + (supplier
 701                                             ? CHECK_ACT_INTERVAL
 702                                             : CHECK_QUIET_INTERVAL);
 703
 704         /* mark all interfaces so we can get rid of those that disappear */
 705         for (ifp = ifnet; 0 != ifp; ifp = ifp->int_next)
 706                 ifp->int_state &= ~(IS_CHECKED | IS_DUP);
 707
 708         /* Fetch the interface list, without too many system calls
 709          * since we do it repeatedly.
 710          */
 711         mib[0] = CTL_NET;
 712         mib[1] = PF_ROUTE;
 713         mib[2] = 0;
 714         mib[3] = AF_INET;
 715         mib[4] = NET_RT_IFLIST;
 716         mib[5] = 0;
 717         for (;;) {
 718                 if ((needed = sysctl_buf_size) != 0) {
 719                         if (sysctl(mib, 6, sysctl_buf,&needed, 0, 0) >= 0)
 720                                 break;
 721                         /* retry if the table grew */
 722                         if (errno != ENOMEM && errno != EFAULT)
 723                                 BADERR(1, "ifinit: sysctl(RT_IFLIST)");
 724                         free(sysctl_buf);
 725                         needed = 0;
 726                 }
 727                 if (sysctl(mib, 6, 0, &needed, 0, 0) < 0)
 728                         BADERR(1,"ifinit: sysctl(RT_IFLIST) estimate");
 729                 sysctl_buf = rtmalloc(sysctl_buf_size = needed,
 730                                       "ifinit sysctl");
 731         }
 732
 733         ifam_lim = (struct ifa_msghdr *)(sysctl_buf + needed);
 734         for (ifam = (struct ifa_msghdr *)sysctl_buf;
 735              ifam < ifam_lim;
 736              ifam = ifam2) {
 737
 738                 ifam2 = (struct ifa_msghdr*)((char*)ifam + ifam->ifam_msglen);
 739
 740                 if (ifam->ifam_type == RTM_IFINFO) {
 741                         struct sockaddr_dl *sdl;
 742
 743                         ifm = (struct if_msghdr *)ifam;
 744                         /* make prototype structure for the IP aliases
 745                          */
 746                         memset(&ifs0, 0, sizeof(ifs0));
 747                         ifs0.int_rip_sock = -1;
 748                         ifs0.int_index = ifm->ifm_index;
 749                         ifs0.int_if_flags = ifm->ifm_flags;
 750                         ifs0.int_state = IS_CHECKED;
 751                         ifs0.int_query_time = NEVER;
 752                         ifs0.int_act_time = now.tv_sec;
 753                         ifs0.int_data.ts = now.tv_sec;
 754                         ifs0.int_data.ipackets = ifm->ifm_data.ifi_ipackets;
 755                         ifs0.int_data.ierrors = ifm->ifm_data.ifi_ierrors;
 756                         ifs0.int_data.opackets = ifm->ifm_data.ifi_opackets;
 757                         ifs0.int_data.oerrors = ifm->ifm_data.ifi_oerrors;
 758 #ifdef sgi
 759                         ifs0.int_data.odrops = ifm->ifm_data.ifi_odrops;
 760 #endif
 761                         sdl = (struct sockaddr_dl *)(ifm + 1);
 762                         sdl->sdl_data[sdl->sdl_nlen] = 0;
 763                         strncpy(ifs0.int_name, sdl->sdl_data,
 764                                 MIN(sizeof(ifs0.int_name), sdl->sdl_nlen));
 765                         continue;
 766                 }
 767                 if (ifam->ifam_type != RTM_NEWADDR) {
 768                         logbad(1,"ifinit: out of sync");
 769                         continue;
 770                 }
 771                 rt_xaddrs(&info, (struct sockaddr *)(ifam+1),
 772                           (struct sockaddr *)ifam2,
 773                           ifam->ifam_addrs);
 774
 775                 /* Prepare for the next address of this interface, which
 776                  * will be an alias.
 777                  * Do not output RIP or Router-Discovery packets via aliases.
 778                  */
 779                 memcpy(&ifs, &ifs0, sizeof(ifs));
 780                 ifs0.int_state |= (IS_ALIAS | IS_NO_RIP_OUT | IS_NO_RDISC);
 781
 782                 if (INFO_IFA(&info) == 0) {
 783                         if (iff_up(ifs.int_if_flags)) {
 784                                 if (!(prev_complaints & COMP_NOADDR))
 785                                         msglog("%s has no address",
 786                                                ifs.int_name);
 787                                 complaints |= COMP_NOADDR;
 788                         }
 789                         continue;
 790                 }
 791                 if (INFO_IFA(&info)->sa_family != AF_INET) {
 792                         if (iff_up(ifs.int_if_flags)) {
 793                                 if (!(prev_complaints & COMP_NOT_INET))
 794                                         trace_act("%s: not AF_INET",
 795                                                   ifs.int_name);
 796                                 complaints |= COMP_NOT_INET;
 797                         }
 798                         continue;
 799                 }
 800
 801                 ifs.int_addr = S_ADDR(INFO_IFA(&info));
 802
 803                 if (ntohl(ifs.int_addr)>>24 == 0
 804                     || ntohl(ifs.int_addr)>>24 == 0xff) {
 805                         if (iff_up(ifs.int_if_flags)) {
 806                                 if (!(prev_complaints & COMP_BADADDR))
 807                                         msglog("%s has a bad address",
 808                                                ifs.int_name);
 809                                 complaints |= COMP_BADADDR;
 810                         }
 811                         continue;
 812                 }
 813
 814                 if (ifs.int_if_flags & IFF_LOOPBACK) {
 815                         ifs.int_state |= IS_PASSIVE | IS_NO_RIP | IS_NO_RDISC;
 816                         ifs.int_dstaddr = ifs.int_addr;
 817                         ifs.int_mask = HOST_MASK;
 818                         ifs.int_ripv1_mask = HOST_MASK;
 819                         ifs.int_std_mask = std_mask(ifs.int_dstaddr);
 820                         ifs.int_net = ntohl(ifs.int_dstaddr);
 821                         if (!foundloopback) {
 822                                 foundloopback = 1;
 823                                 loopaddr = ifs.int_addr;
 824                                 loop_rts.rts_gate = loopaddr;
 825                                 loop_rts.rts_router = loopaddr;
 826                         }
 827
 828                 } else if (ifs.int_if_flags & IFF_POINTOPOINT) {
 829                         if (INFO_BRD(&info) == 0
 830                             || INFO_BRD(&info)->sa_family != AF_INET) {
 831                                 if (iff_up(ifs.int_if_flags)) {
 832                                         if (!(prev_complaints & COMP_NODST))
 833                                                 msglog("%s has a bad"
 834                                                        " destination address",
 835                                                        ifs.int_name);
 836                                         complaints |= COMP_NODST;
 837                                 }
 838                                 continue;
 839                         }
 840                         ifs.int_dstaddr = S_ADDR(INFO_BRD(&info));
 841                         if (ntohl(ifs.int_dstaddr)>>24 == 0
 842                             || ntohl(ifs.int_dstaddr)>>24 == 0xff) {
 843                                 if (iff_up(ifs.int_if_flags)) {
 844                                         if (!(prev_complaints & COMP_NODST))
 845                                                 msglog("%s has a bad"
 846                                                        " destination address",
 847                                                        ifs.int_name);
 848                                         complaints |= COMP_NODST;
 849                                 }
 850                                 continue;
 851                         }
 852                         ifs.int_mask = HOST_MASK;
 853                         ifs.int_ripv1_mask = ntohl(S_ADDR(INFO_MASK(&info)));
 854                         ifs.int_std_mask = std_mask(ifs.int_dstaddr);
 855                         ifs.int_net = ntohl(ifs.int_dstaddr);
 856
 857                 }  else {
 858                         if (INFO_MASK(&info) == 0) {
 859                                 if (iff_up(ifs.int_if_flags)) {
 860                                         if (!(prev_complaints & COMP_NOMASK))
 861                                                 msglog("%s has no netmask",
 862                                                        ifs.int_name);
 863                                         complaints |= COMP_NOMASK;
 864                                 }
 865                                 continue;
 866                         }
 867                         ifs.int_dstaddr = ifs.int_addr;
 868                         ifs.int_mask = ntohl(S_ADDR(INFO_MASK(&info)));
 869                         ifs.int_ripv1_mask = ifs.int_mask;
 870                         ifs.int_std_mask = std_mask(ifs.int_addr);
 871                         ifs.int_net = ntohl(ifs.int_addr) & ifs.int_mask;
 872                         if (ifs.int_mask != ifs.int_std_mask)
 873                                 ifs.int_state |= IS_SUBNET;
 874
 875                         if (ifs.int_if_flags & IFF_BROADCAST) {
 876                                 if (INFO_BRD(&info) == 0) {
 877                                         if (iff_up(ifs.int_if_flags)) {
 878                                             if (!(prev_complaints
 879                                                   & COMP_NOBADR))
 880                                                 msglog("%s has"
 881                                                        "no broadcast address",
 882                                                        ifs.int_name);
 883                                             complaints |= COMP_NOBADR;
 884                                         }
 885                                         continue;
 886                                 }
 887                                 ifs.int_brdaddr = S_ADDR(INFO_BRD(&info));
 888                         }
 889                 }
 890                 ifs.int_std_net = ifs.int_net & ifs.int_std_mask;
 891                 ifs.int_std_addr = htonl(ifs.int_std_net);
 892
 893                 /* Use a minimum metric of one.  Treat the interface metric
 894                  * (default 0) as an increment to the hop count of one.
 895                  *
 896                  * The metric obtained from the routing socket dump of
 897                  * interface addresses is wrong.  It is not set by the
 898                  * SIOCSIFMETRIC ioctl.
 899                  */
 900 #ifdef SIOCGIFMETRIC
 901                 strncpy(ifr.ifr_name, ifs.int_name, sizeof(ifr.ifr_name));
 902                 if (ioctl(rt_sock, SIOCGIFMETRIC, &ifr) < 0) {
 903                         DBGERR(1, "ioctl(SIOCGIFMETRIC)");
 904                         ifs.int_metric = 0;
 905                 } else {
 906                         ifs.int_metric = ifr.ifr_metric;
 907                 }
 908 #else
 909                 ifs.int_metric = ifam->ifam_metric;
 910 #endif
 911                 if (ifs.int_metric > HOPCNT_INFINITY) {
 912                         ifs.int_metric = 0;
 913                         if (!(prev_complaints & COMP_BAD_METRIC)
 914                             && iff_up(ifs.int_if_flags)) {
 915                                 complaints |= COMP_BAD_METRIC;
 916                                 msglog("%s has a metric of %d",
 917                                        ifs.int_name, ifs.int_metric);
 918                         }
 919                 }
 920
 921                 /* See if this is a familiar interface.
 922                  * If so, stop worrying about it if it is the same.
 923                  * Start it over if it now is to somewhere else, as happens
 924                  * frequently with PPP and SLIP.
 925                  */
 926                 ifp = ifwithname(ifs.int_name, ((ifs.int_state & IS_ALIAS)
 927                                                 ? ifs.int_addr
 928                                                 : 0));
 929                 if (ifp != 0) {
 930                         ifp->int_state |= IS_CHECKED;
 931
 932                         if (0 != ((ifp->int_if_flags ^ ifs.int_if_flags)
 933                                   & (IFF_BROADCAST
 934                                      | IFF_LOOPBACK
 935                                      | IFF_POINTOPOINT
 936                                      | IFF_MULTICAST))
 937                             || 0 != ((ifp->int_state ^ ifs.int_state)
 938                                      & IS_ALIAS)
 939                             || ifp->int_addr != ifs.int_addr
 940                             || ifp->int_brdaddr != ifs.int_brdaddr
 941                             || ifp->int_dstaddr != ifs.int_dstaddr
 942                             || ifp->int_mask != ifs.int_mask
 943                             || ifp->int_metric != ifs.int_metric) {
 944                                 /* Forget old information about
 945                                  * a changed interface.
 946                                  */
 947                                 trace_act("interface %s has changed",
 948                                           ifp->int_name);
 949                                 ifdel(ifp);
 950                                 ifp = 0;
 951                         }
 952                 }
 953
 954                 if (ifp != 0) {
 955                         /* The primary representative of an alias worries
 956                          * about how things are working.
 957                          */
 958                         if (ifp->int_state & IS_ALIAS)
 959                                 continue;
 960
 961                         /* note interfaces that have been turned off
 962                          */
 963                         if (!iff_up(ifs.int_if_flags)) {
 964                                 if (iff_up(ifp->int_if_flags)) {
 965                                         msglog("interface %s to %s turned off",
 966                                                ifp->int_name,
 967                                                naddr_ntoa(ifp->int_dstaddr));
 968                                         if_bad(ifp);
 969                                         ifp->int_if_flags &= ~IFF_UP;
 970                                 } else if (now.tv_sec>(ifp->int_data.ts
 971                                                        + CHECK_BAD_INTERVAL)) {
 972                                         trace_act("interface %s has been off"
 973                                                   " %ld seconds; forget it",
 974                                                   ifp->int_name,
 975                                                   now.tv_sec-ifp->int_data.ts);
 976                                         ifdel(ifp);
 977                                 }
 978                                 continue;
 979                         }
 980                         /* or that were off and are now ok */
 981                         if (!iff_up(ifp->int_if_flags)) {
 982                                 ifp->int_if_flags |= IFF_UP;
 983                                 if_ok(ifp, "");
 984                         }
 985
 986                         /* If it has been long enough,
 987                          * see if the interface is broken.
 988                          */
 989                         if (now.tv_sec < ifp->int_data.ts+CHECK_BAD_INTERVAL)
 990                                 continue;
 991
 992                         in = ifs.int_data.ipackets - ifp->int_data.ipackets;
 993                         ierr = ifs.int_data.ierrors - ifp->int_data.ierrors;
 994                         out = ifs.int_data.opackets - ifp->int_data.opackets;
 995                         oerr = ifs.int_data.oerrors - ifp->int_data.oerrors;
 996 #ifdef sgi
 997                         /* Through at least IRIX 6.2, PPP and SLIP
 998                          * count packets dropped by the filters.
 999                          * But FDDI rings stuck non-operational count
1000                          * dropped packets as they wait for improvement.
1001                          */
1002                         if (!(ifp->int_if_flags & IFF_POINTOPOINT))
1003                                 oerr += (ifs.int_data.odrops
1004                                          - ifp->int_data.odrops);
1005 #endif
1006                         /* If the interface just awoke, restart the counters.
1007                          */
1008                         if (ifp->int_data.ts == 0) {
1009                                 ifp->int_data = ifs.int_data;
1010                                 continue;
1011                         }
1012                         ifp->int_data = ifs.int_data;
1013
1014                         /* Withhold judgment when the short error
1015                          * counters wrap or the interface is reset.
1016                          */
1017                         if (ierr < 0 || in < 0 || oerr < 0 || out < 0) {
1018                                 LIM_SEC(ifinit_timer,
1019                                         now.tv_sec+CHECK_BAD_INTERVAL);
1020                                 continue;
1021                         }
1022
1023                         /* Withhold judgement when there is no traffic
1024                          */
1025                         if (in == 0 && out == 0 && ierr == 0 && oerr == 0)
1026                                 continue;
1027
1028                         /* It is bad if input or output is not working.
1029                          * Require presistent problems before marking it dead.
1030                          */
1031                         if ((in <= ierr && ierr > 0)
1032                             || (out <= oerr && oerr > 0)) {
1033                                 if (!(ifp->int_state & IS_SICK)) {
1034                                         trace_act("interface %s to %s"
1035                                                   " sick: in=%d ierr=%d"
1036                                                   " out=%d oerr=%d",
1037                                                   ifp->int_name,
1038                                                   naddr_ntoa(ifp->int_dstaddr),
1039                                                   in, ierr, out, oerr);
1040                                         if_sick(ifp);
1041                                         continue;
1042                                 }
1043                                 if (!(ifp->int_state & IS_BROKE)) {
1044                                         msglog("interface %s to %s broken:"
1045                                                " in=%d ierr=%d out=%d oerr=%d",
1046                                                ifp->int_name,
1047                                                naddr_ntoa(ifp->int_dstaddr),
1048                                                in, ierr, out, oerr);
1049                                         if_bad(ifp);
1050                                 }
1051                                 continue;
1052                         }
1053
1054                         /* otherwise, it is active and healthy
1055                          */
1056                         ifp->int_act_time = now.tv_sec;
1057                         if_ok(ifp, "");
1058                         continue;
1059                 }
1060
1061                 /* This is a new interface.
1062                  * If it is dead, forget it.
1063                  */
1064                 if (!iff_up(ifs.int_if_flags))
1065                         continue;
1066
1067                 /* If it duplicates an existing interface,
1068                  * complain about it, mark the other one
1069                  * duplicated, and forget this one.
1070                  */
1071                 ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
1072                                 ifs.int_if_flags);
1073                 if (ifp != 0) {
1074                         /* Ignore duplicates of itself, caused by having
1075                          * IP aliases on the same network.
1076                          */
1077                         if (!strcmp(ifp->int_name, ifs.int_name))
1078                                 continue;
1079
1080                         if (!(prev_complaints & COMP_DUP)) {
1081                                 complaints |= COMP_DUP;
1082                                 msglog("%s (%s%s%s) is duplicated by"
1083                                        " %s (%s%s%s)",
1084                                        ifs.int_name,
1085                                        addrname(ifs.int_addr,ifs.int_mask,1),
1086                                        ((ifs.int_if_flags & IFF_POINTOPOINT)
1087                                         ? "-->" : ""),
1088                                        ((ifs.int_if_flags & IFF_POINTOPOINT)
1089                                         ? naddr_ntoa(ifs.int_dstaddr) : ""),
1090                                        ifp->int_name,
1091                                        addrname(ifp->int_addr,ifp->int_mask,1),
1092                                        ((ifp->int_if_flags & IFF_POINTOPOINT)
1093                                         ? "-->" : ""),
1094                                        ((ifp->int_if_flags & IFF_POINTOPOINT)
1095                                         ? naddr_ntoa(ifp->int_dstaddr) : ""));
1096                         }
1097                         ifp->int_state |= IS_DUP;
1098                         continue;
1099                 }
1100
1101                 if (0 == (ifs.int_if_flags & (IFF_POINTOPOINT | IFF_BROADCAST))
1102                     && !(ifs.int_state & IS_PASSIVE)) {
1103                         trace_act("%s is neither broadcast, point-to-point,"
1104                                   " nor loopback",
1105                                   ifs.int_name);
1106                         if (!(ifs.int_state & IFF_MULTICAST))
1107                                 ifs.int_state |= IS_NO_RDISC;
1108                 }
1109
1110
1111                 /* It is new and ok.   Add it to the list of interfaces
1112                  */
1113                 ifp = (struct interface *)rtmalloc(sizeof(*ifp), "ifinit ifp");
1114                 memcpy(ifp, &ifs, sizeof(*ifp));
1115                 get_parms(ifp);
1116                 if_link(ifp);
1117                 trace_if("Add", ifp);
1118
1119                 /* Notice likely bad netmask.
1120                  */
1121                 if (!(prev_complaints & COMP_NETMASK)
1122                     && !(ifp->int_if_flags & IFF_POINTOPOINT)
1123                     && ifp->int_addr != RIP_DEFAULT) {
1124                         for (ifp1 = ifnet; 0 != ifp1; ifp1 = ifp1->int_next) {
1125                                 if (ifp1->int_mask == ifp->int_mask)
1126                                         continue;
1127                                 if (ifp1->int_if_flags & IFF_POINTOPOINT)
1128                                         continue;
1129                                 if (ifp1->int_dstaddr == RIP_DEFAULT)
1130                                         continue;
1131                                 /* ignore aliases on the right network */
1132                                 if (!strcmp(ifp->int_name, ifp1->int_name))
1133                                         continue;
1134                                 if (on_net(ifp->int_dstaddr,
1135                                            ifp1->int_net, ifp1->int_mask)
1136                                     || on_net(ifp1->int_dstaddr,
1137                                               ifp->int_net, ifp->int_mask)) {
1138                                         msglog("possible netmask problem"
1139                                                " between %s:%s and %s:%s",
1140                                                ifp->int_name,
1141                                                addrname(htonl(ifp->int_net),
1142                                                         ifp->int_mask, 1),
1143                                                ifp1->int_name,
1144                                                addrname(htonl(ifp1->int_net),
1145                                                         ifp1->int_mask, 1));
1146                                         complaints |= COMP_NETMASK;
1147                                 }
1148                         }
1149                 }
1150
1151                 if (!(ifp->int_state & IS_ALIAS)) {
1152                         /* Count the # of directly connected networks.
1153                          */
1154                         if (!(ifp->int_if_flags & IFF_LOOPBACK))
1155                                 tot_interfaces++;
1156                         if (!IS_RIP_OFF(ifp->int_state))
1157                                 rip_interfaces++;
1158
1159                         /* turn on router discovery and RIP If needed */
1160                         if_ok_rdisc(ifp);
1161                         rip_on(ifp);
1162                 }
1163         }
1164
1165         /* If we are multi-homed and have at least two interfaces
1166          * listening to RIP, then output by default.
1167          */
1168         if (!supplier_set && rip_interfaces > 1)
1169                 set_supplier();
1170
1171         /* If we are multi-homed, optionally advertise a route to
1172          * our main address.
1173          */
1174         if (advertise_mhome
1175             || (tot_interfaces > 1
1176                 && mhome
1177                 && (ifp = ifwithaddr(myaddr, 0, 0)) != 0
1178                 && foundloopback)) {
1179                 advertise_mhome = 1;
1180                 rt = rtget(myaddr, HOST_MASK);
1181                 if (rt != 0) {
1182                         if (rt->rt_ifp != ifp
1183                             || rt->rt_router != loopaddr) {
1184                                 rtdelete(rt);
1185                                 rt = 0;
1186                         } else {
1187                                 loop_rts.rts_ifp = ifp;
1188                                 loop_rts.rts_metric = 0;
1189                                 loop_rts.rts_time = rt->rt_time;
1190                                 rtchange(rt, rt->rt_state | RS_MHOME,
1191                                          &loop_rts, 0);
1192                         }
1193                 }
1194                 if (rt == 0) {
1195                         loop_rts.rts_ifp = ifp;
1196                         loop_rts.rts_metric = 0;
1197                         rtadd(myaddr, HOST_MASK, RS_MHOME, &loop_rts);
1198                 }
1199         }
1200
1201         for (ifp = ifnet; ifp != 0; ifp = ifp1) {
1202                 ifp1 = ifp->int_next;   /* because we may delete it */
1203
1204                 /* Forget any interfaces that have disappeared.
1205                  */
1206                 if (!(ifp->int_state & (IS_CHECKED | IS_REMOTE))) {
1207                         trace_act("interface %s has disappeared",
1208                                   ifp->int_name);
1209                         ifdel(ifp);
1210                         continue;
1211                 }
1212
1213                 if ((ifp->int_state & IS_BROKE)
1214                     && !(ifp->int_state & IS_PASSIVE))
1215                         LIM_SEC(ifinit_timer, now.tv_sec+CHECK_BAD_INTERVAL);
1216
1217                 /* If we ever have a RIPv1 interface, assume we always will.
1218                  * It might come back if it ever goes away.
1219                  */
1220                 if (!(ifp->int_state & IS_NO_RIPV1_OUT) && supplier)
1221                         have_ripv1_out = 1;
1222                 if (!(ifp->int_state & IS_NO_RIPV1_IN))
1223                         have_ripv1_in = 1;
1224         }
1225
1226         for (ifp = ifnet; ifp != 0; ifp = ifp->int_next) {
1227                 /* Ensure there is always a network route for interfaces,
1228                  * after any dead interfaces have been deleted, which
1229                  * might affect routes for point-to-point links.
1230                  */
1231                 if (!addrouteforif(ifp))
1232                         continue;
1233
1234                 /* Add routes to the local end of point-to-point interfaces
1235                  * using loopback.
1236                  */
1237                 if ((ifp->int_if_flags & IFF_POINTOPOINT)
1238                     && !(ifp->int_state & IS_REMOTE)
1239                     && foundloopback) {
1240                         /* Delete any routes to the network address through
1241                          * foreign routers. Remove even static routes.
1242                          */
1243                         del_static(ifp->int_addr, HOST_MASK, 0, 0);
1244                         rt = rtget(ifp->int_addr, HOST_MASK);
1245                         if (rt != 0 && rt->rt_router != loopaddr) {
1246                                 rtdelete(rt);
1247                                 rt = 0;
1248                         }
1249                         if (rt != 0) {
1250                                 if (!(rt->rt_state & RS_LOCAL)
1251                                     || rt->rt_metric > ifp->int_metric) {
1252                                         ifp1 = ifp;
1253                                 } else {
1254                                         ifp1 = rt->rt_ifp;
1255                                 }
1256                                 loop_rts.rts_ifp = ifp1;
1257                                 loop_rts.rts_metric = 0;
1258                                 loop_rts.rts_time = rt->rt_time;
1259                                 rtchange(rt, ((rt->rt_state & ~RS_NET_SYN)
1260                                               | (RS_IF|RS_LOCAL)),
1261                                          &loop_rts, 0);
1262                         } else {
1263                                 loop_rts.rts_ifp = ifp;
1264                                 loop_rts.rts_metric = 0;
1265                                 rtadd(ifp->int_addr, HOST_MASK,
1266                                       (RS_IF | RS_LOCAL), &loop_rts);
1267                         }
1268                 }
1269         }
1270
1271         /* add the authority routes */
1272         for (intnetp = intnets; intnetp!=0; intnetp = intnetp->intnet_next) {
1273                 rt = rtget(intnetp->intnet_addr, intnetp->intnet_mask);
1274                 if (rt != 0
1275                     && !(rt->rt_state & RS_NO_NET_SYN)
1276                     && !(rt->rt_state & RS_NET_INT)) {
1277                         rtdelete(rt);
1278                         rt = 0;
1279                 }
1280                 if (rt == 0) {
1281                         loop_rts.rts_ifp = 0;
1282                         loop_rts.rts_metric = intnetp->intnet_metric-1;
1283                         rtadd(intnetp->intnet_addr, intnetp->intnet_mask,
1284                               RS_NET_SYN | RS_NET_INT, &loop_rts);
1285                 }
1286         }
1287
1288         prev_complaints = complaints;
1289 }
1290
1291
1292 static void
1293 check_net_syn(struct interface *ifp)
1294 {
1295         struct rt_entry *rt;
1296         static struct rt_spare new;
1297
1298
1299         /* Turn on the need to automatically synthesize a network route
1300          * for this interface only if we are running RIPv1 on some other
1301          * interface that is on a different class-A,B,or C network.
1302          */
1303         if (have_ripv1_out || have_ripv1_in) {
1304                 ifp->int_state |= IS_NEED_NET_SYN;
1305                 rt = rtget(ifp->int_std_addr, ifp->int_std_mask);
1306                 if (rt != 0
1307                     && 0 == (rt->rt_state & RS_NO_NET_SYN)
1308                     && (!(rt->rt_state & RS_NET_SYN)
1309                         || rt->rt_metric > ifp->int_metric)) {
1310                         rtdelete(rt);
1311                         rt = 0;
1312                 }
1313                 if (rt == 0) {
1314                         new.rts_ifp = ifp;
1315                         new.rts_gate = ifp->int_addr;
1316                         new.rts_router = ifp->int_addr;
1317                         new.rts_metric = ifp->int_metric;
1318                         rtadd(ifp->int_std_addr, ifp->int_std_mask,
1319                               RS_NET_SYN, &new);
1320                 }
1321
1322         } else {
1323                 ifp->int_state &= ~IS_NEED_NET_SYN;
1324
1325                 rt = rtget(ifp->int_std_addr,
1326                            ifp->int_std_mask);
1327                 if (rt != 0
1328                     && (rt->rt_state & RS_NET_SYN)
1329                     && rt->rt_ifp == ifp)
1330                         rtbad_sub(rt);
1331         }
1332 }
1333
1334
1335 /* Add route for interface if not currently installed.
1336  * Create route to other end if a point-to-point link,
1337  * otherwise a route to this (sub)network.
1338  */
1339 int                                     /* 0=bad interface */
1340 addrouteforif(struct interface *ifp)
1341 {
1342         struct rt_entry *rt;
1343         static struct rt_spare new;
1344         naddr dst;
1345
1346
1347         /* skip sick interfaces
1348          */
1349         if (ifp->int_state & IS_BROKE)
1350                 return 0;
1351
1352         /* If the interface on a subnet, then install a RIPv1 route to
1353          * the network as well (unless it is sick).
1354          */
1355         if (ifp->int_state & IS_SUBNET)
1356                 check_net_syn(ifp);
1357
1358         dst = (0 != (ifp->int_if_flags & (IFF_POINTOPOINT | IFF_LOOPBACK))
1359                ? ifp->int_dstaddr
1360                : htonl(ifp->int_net));
1361
1362         new.rts_ifp = ifp;
1363         new.rts_router = ifp->int_addr;
1364         new.rts_gate = ifp->int_addr;
1365         new.rts_metric = ifp->int_metric;
1366         new.rts_time = now.tv_sec;
1367
1368         /* If we are going to send packets to the gateway,
1369          * it must be reachable using our physical interfaces
1370          */
1371         if ((ifp->int_state & IS_REMOTE)
1372             && !(ifp->int_state & IS_EXTERNAL)
1373             && !check_remote(ifp))
1374                 return 0;
1375
1376         /* We are finished if the correct main interface route exists.
1377          * The right route must be for the right interface, not synthesized
1378          * from a subnet, be a "gateway" or not as appropriate, and so forth.
1379          */
1380         del_static(dst, ifp->int_mask, 0, 0);
1381         rt = rtget(dst, ifp->int_mask);
1382         if (rt != 0) {
1383                 if ((rt->rt_ifp != ifp
1384                      || rt->rt_router != ifp->int_addr)
1385                     && (!(ifp->int_state & IS_DUP)
1386                         || rt->rt_ifp == 0
1387                         || (rt->rt_ifp->int_state & IS_BROKE))) {
1388                         rtdelete(rt);
1389                         rt = 0;
1390                 } else {
1391                         rtchange(rt, ((rt->rt_state | RS_IF)
1392                                       & ~(RS_NET_SYN | RS_LOCAL)),
1393                                  &new, 0);
1394                 }
1395         }
1396         if (rt == 0) {
1397                 if (ifp->int_transitions++ > 0)
1398                         trace_act("re-install interface %s",
1399                                   ifp->int_name);
1400
1401                 rtadd(dst, ifp->int_mask, RS_IF, &new);
1402         }
1403
1404         return 1;
1405 }