ospfd/ospf_ism.c

   1 /*
   2  * OSPF version 2  Interface State Machine
   3  *   From RFC2328 [OSPF Version 2]
   4  * Copyright (C) 1999, 2000 Toshiaki Takada
   5  *
   6  * This file is part of GNU Zebra.
   7  *
   8  * GNU Zebra is free software; you can redistribute it and/or modify it
   9  * under the terms of the GNU General Public License as published by the
  10  * Free Software Foundation; either version 2, or (at your option) any
  11  * later version.
  12  *
  13  * GNU Zebra is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with GNU Zebra; see the file COPYING.  If not, write to the Free
  20  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
  21  * 02111-1307, USA.
  22  */
  23
  24 #include <zebra.h>
  25
  26 #include "thread.h"
  27 #include "linklist.h"
  28 #include "prefix.h"
  29 #include "if.h"
  30 #include "table.h"
  31 #include "log.h"
  32
  33 #include "ospfd/ospfd.h"
  34 #include "ospfd/ospf_interface.h"
  35 #include "ospfd/ospf_ism.h"
  36 #include "ospfd/ospf_asbr.h"
  37 #include "ospfd/ospf_lsa.h"
  38 #include "ospfd/ospf_lsdb.h"
  39 #include "ospfd/ospf_neighbor.h"
  40 #include "ospfd/ospf_nsm.h"
  41 #include "ospfd/ospf_network.h"
  42 #include "ospfd/ospf_dump.h"
  43 #include "ospfd/ospf_packet.h"
  44 #include "ospfd/ospf_flood.h"
  45 #include "ospfd/ospf_abr.h"
  46 \f
  47 /* elect DR and BDR. Refer to RFC2319 section 9.4 */
  48 struct ospf_neighbor *
  49 ospf_dr_election_sub (struct list *routers)
  50 {
  51   struct listnode *node;
  52   struct ospf_neighbor *nbr, *max = NULL;
  53
  54   /* Choose highest router priority.
  55      In case of tie, choose highest Router ID. */
  56   for (ALL_LIST_ELEMENTS_RO (routers, node, nbr))
  57     {
  58       if (max == NULL)
  59         max = nbr;
  60       else
  61         {
  62           if (max->priority < nbr->priority)
  63             max = nbr;
  64           else if (max->priority == nbr->priority)
  65             if (IPV4_ADDR_CMP (&max->router_id, &nbr->router_id) < 0)
  66               max = nbr;
  67         }
  68     }
  69
  70   return max;
  71 }
  72
  73 struct ospf_neighbor *
  74 ospf_elect_dr (struct ospf_interface *oi, struct list *el_list)
  75 {
  76   struct list *dr_list;
  77   struct listnode *node;
  78   struct ospf_neighbor *nbr, *dr = NULL, *bdr = NULL;
  79
  80   dr_list = list_new ();
  81
  82   /* Add neighbors to the list. */
  83   for (ALL_LIST_ELEMENTS_RO (el_list, node, nbr))
  84     {
  85       /* neighbor declared to be DR. */
  86       if (NBR_IS_DR (nbr))
  87         listnode_add (dr_list, nbr);
  88
  89       /* Preserve neighbor BDR. */
  90       if (IPV4_ADDR_SAME (&BDR (oi), &nbr->address.u.prefix4))
  91         bdr = nbr;
  92     }
  93
  94   /* Elect Designated Router. */
  95   if (listcount (dr_list) > 0)
  96     dr = ospf_dr_election_sub (dr_list);
  97   else
  98     dr = bdr;
  99
 100   /* Set DR to interface. */
 101   if (dr)
 102     {
 103       DR (oi) = dr->address.u.prefix4;
 104       dr->d_router = dr->address.u.prefix4;
 105     }
 106   else
 107       DR (oi).s_addr = 0;
 108
 109   list_delete (dr_list);
 110
 111   return dr;
 112 }
 113
 114 struct ospf_neighbor *
 115 ospf_elect_bdr (struct ospf_interface *oi, struct list *el_list)
 116 {
 117   struct list *bdr_list, *no_dr_list;
 118   struct listnode *node;
 119   struct ospf_neighbor *nbr, *bdr = NULL;
 120
 121   bdr_list = list_new ();
 122   no_dr_list = list_new ();
 123
 124   /* Add neighbors to the list. */
 125   for (ALL_LIST_ELEMENTS_RO (el_list, node, nbr))
 126     {
 127       /* neighbor declared to be DR. */
 128       if (NBR_IS_DR (nbr))
 129         continue;
 130
 131       /* neighbor declared to be BDR. */
 132       if (NBR_IS_BDR (nbr))
 133         listnode_add (bdr_list, nbr);
 134
 135       listnode_add (no_dr_list, nbr);
 136     }
 137
 138   /* Elect Backup Designated Router. */
 139   if (listcount (bdr_list) > 0)
 140     bdr = ospf_dr_election_sub (bdr_list);
 141   else
 142     bdr = ospf_dr_election_sub (no_dr_list);
 143
 144   /* Set BDR to interface. */
 145   if (bdr)
 146     {
 147       BDR (oi) = bdr->address.u.prefix4;
 148       bdr->bd_router = bdr->address.u.prefix4;
 149     }
 150   else
 151     BDR (oi).s_addr = 0;
 152
 153   list_delete (bdr_list);
 154   list_delete (no_dr_list);
 155
 156   return bdr;
 157 }
 158
 159 int
 160 ospf_ism_state (struct ospf_interface *oi)
 161 {
 162   if (IPV4_ADDR_SAME (&DR (oi), &oi->address->u.prefix4))
 163     return ISM_DR;
 164   else if (IPV4_ADDR_SAME (&BDR (oi), &oi->address->u.prefix4))
 165     return ISM_Backup;
 166   else
 167     return ISM_DROther;
 168 }
 169
 170 void
 171 ospf_dr_eligible_routers (struct route_table *nbrs, struct list *el_list)
 172 {
 173   struct route_node *rn;
 174   struct ospf_neighbor *nbr;
 175
 176   for (rn = route_top (nbrs); rn; rn = route_next (rn))
 177     if ((nbr = rn->info) != NULL)
 178       /* Ignore 0.0.0.0 node*/
 179       if (nbr->router_id.s_addr != 0)
 180         /* Is neighbor eligible? */
 181         if (nbr->priority != 0)
 182           /* Is neighbor upper 2-Way? */
 183           if (nbr->state >= NSM_TwoWay)
 184             listnode_add (el_list, nbr);
 185 }
 186
 187 /* Generate AdjOK? NSM event. */
 188 void
 189 ospf_dr_change (struct ospf *ospf, struct route_table *nbrs)
 190 {
 191   struct route_node *rn;
 192   struct ospf_neighbor *nbr;
 193
 194   for (rn = route_top (nbrs); rn; rn = route_next (rn))
 195     if ((nbr = rn->info) != NULL)
 196       /* Ignore 0.0.0.0 node*/
 197       if (nbr->router_id.s_addr != 0)
 198         /* Is neighbor upper 2-Way? */
 199         if (nbr->state >= NSM_TwoWay)
 200           /* Ignore myself. */
 201           if (!IPV4_ADDR_SAME (&nbr->router_id, &ospf->router_id))
 202             OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_AdjOK);
 203 }
 204
 205 int
 206 ospf_dr_election (struct ospf_interface *oi)
 207 {
 208   struct in_addr old_dr, old_bdr;
 209   int old_state, new_state;
 210   struct list *el_list;
 211   struct ospf_neighbor *dr, *bdr;
 212
 213   /* backup current values. */
 214   old_dr = DR (oi);
 215   old_bdr = BDR (oi);
 216   old_state = oi->state;
 217
 218   el_list = list_new ();
 219
 220   /* List eligible routers. */
 221   ospf_dr_eligible_routers (oi->nbrs, el_list);
 222
 223   /* First election of DR and BDR. */
 224   bdr = ospf_elect_bdr (oi, el_list);
 225   dr = ospf_elect_dr (oi, el_list);
 226
 227   new_state = ospf_ism_state (oi);
 228
 229   zlog_info ("DR-Election[1st]: Backup %s", inet_ntoa (BDR (oi)));
 230   zlog_info ("DR-Election[1st]: DR     %s", inet_ntoa (DR (oi)));
 231
 232   if (new_state != old_state &&
 233       !(new_state == ISM_DROther && old_state < ISM_DROther))
 234     {
 235       ospf_elect_bdr (oi, el_list);
 236       ospf_elect_dr (oi, el_list);
 237
 238       new_state = ospf_ism_state (oi);
 239
 240       zlog_info ("DR-Election[2nd]: Backup %s", inet_ntoa (BDR (oi)));
 241       zlog_info ("DR-Election[2nd]: DR     %s", inet_ntoa (DR (oi)));
 242     }
 243
 244   list_delete (el_list);
 245
 246   /* if DR or BDR changes, cause AdjOK? neighbor event. */
 247   if (!IPV4_ADDR_SAME (&old_dr, &DR (oi)) ||
 248       !IPV4_ADDR_SAME (&old_bdr, &BDR (oi)))
 249     ospf_dr_change (oi->ospf, oi->nbrs);
 250
 251   return new_state;
 252 }
 253
 254 \f
 255 int
 256 ospf_hello_timer (struct thread *thread)
 257 {
 258   struct ospf_interface *oi;
 259
 260   oi = THREAD_ARG (thread);
 261   oi->t_hello = NULL;
 262
 263   if (IS_DEBUG_OSPF (ism, ISM_TIMERS))
 264     zlog (NULL, LOG_DEBUG, "ISM[%s]: Timer (Hello timer expire)",
 265           IF_NAME (oi));
 266
 267   /* Sending hello packet. */
 268   ospf_hello_send (oi);
 269
 270   /* Hello timer set. */
 271   OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
 272                      OSPF_IF_PARAM (oi, v_hello));
 273
 274   return 0;
 275 }
 276
 277 int
 278 ospf_wait_timer (struct thread *thread)
 279 {
 280   struct ospf_interface *oi;
 281
 282   oi = THREAD_ARG (thread);
 283   oi->t_wait = NULL;
 284
 285   if (IS_DEBUG_OSPF (ism, ISM_TIMERS))
 286     zlog (NULL, LOG_DEBUG, "ISM[%s]: Timer (Wait timer expire)",
 287           IF_NAME (oi));
 288
 289   OSPF_ISM_EVENT_SCHEDULE (oi, ISM_WaitTimer);
 290
 291   return 0;
 292 }
 293
 294 /* Hook function called after ospf ISM event is occured. And vty's
 295    network command invoke this function after making interface
 296    structure. */
 297 void
 298 ism_timer_set (struct ospf_interface *oi)
 299 {
 300   switch (oi->state)
 301     {
 302     case ISM_Down:
 303       /* First entry point of ospf interface state machine. In this state
 304          interface parameters must be set to initial values, and timers are
 305          reset also. */
 306       OSPF_ISM_TIMER_OFF (oi->t_hello);
 307       OSPF_ISM_TIMER_OFF (oi->t_wait);
 308       OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
 309       break;
 310     case ISM_Loopback:
 311       /* In this state, the interface may be looped back and will be
 312          unavailable for regular data traffic. */
 313       OSPF_ISM_TIMER_OFF (oi->t_hello);
 314       OSPF_ISM_TIMER_OFF (oi->t_wait);
 315       OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
 316       break;
 317     case ISM_Waiting:
 318       /* The router is trying to determine the identity of DRouter and
 319          BDRouter. The router begin to receive and send Hello Packets. */
 320       /* send first hello immediately */
 321       OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
 322       OSPF_ISM_TIMER_ON (oi->t_wait, ospf_wait_timer,
 323                          OSPF_IF_PARAM (oi, v_wait));
 324       OSPF_ISM_TIMER_OFF (oi->t_ls_ack);
 325       break;
 326     case ISM_PointToPoint:
 327       /* The interface connects to a physical Point-to-point network or
 328          virtual link. The router attempts to form an adjacency with
 329          neighboring router. Hello packets are also sent. */
 330       /* send first hello immediately */
 331       OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer, 1);
 332
 333       OSPF_ISM_TIMER_OFF (oi->t_wait);
 334       OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
 335       break;
 336     case ISM_DROther:
 337       /* The network type of the interface is broadcast or NBMA network,
 338          and the router itself is neither Designated Router nor
 339          Backup Designated Router. */
 340       OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
 341                          OSPF_IF_PARAM (oi, v_hello));
 342       OSPF_ISM_TIMER_OFF (oi->t_wait);
 343       OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
 344       break;
 345     case ISM_Backup:
 346       /* The network type of the interface is broadcast os NBMA network,
 347          and the router is Backup Designated Router. */
 348       OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
 349                          OSPF_IF_PARAM (oi, v_hello));
 350       OSPF_ISM_TIMER_OFF (oi->t_wait);
 351       OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
 352       break;
 353     case ISM_DR:
 354       /* The network type of the interface is broadcast or NBMA network,
 355          and the router is Designated Router. */
 356       OSPF_ISM_TIMER_ON (oi->t_hello, ospf_hello_timer,
 357                          OSPF_IF_PARAM (oi, v_hello));
 358       OSPF_ISM_TIMER_OFF (oi->t_wait);
 359       OSPF_ISM_TIMER_ON (oi->t_ls_ack, ospf_ls_ack_timer, oi->v_ls_ack);
 360       break;
 361     }
 362 }
 363
 364 int
 365 ism_stop (struct ospf_interface *oi)
 366 {
 367   return 0;
 368 }
 369
 370 int
 371 ism_interface_up (struct ospf_interface *oi)
 372 {
 373   int next_state = 0;
 374
 375   /* if network type is point-to-point, Point-to-MultiPoint or virtual link,
 376      the state transitions to Point-to-Point. */
 377   if (oi->type == OSPF_IFTYPE_POINTOPOINT ||
 378       oi->type == OSPF_IFTYPE_POINTOMULTIPOINT ||
 379       oi->type == OSPF_IFTYPE_VIRTUALLINK)
 380     next_state = ISM_PointToPoint;
 381   /* Else if the router is not eligible to DR, the state transitions to
 382      DROther. */
 383   else if (PRIORITY (oi) == 0) /* router is eligible? */
 384     next_state = ISM_DROther;
 385   else
 386     /* Otherwise, the state transitions to Waiting. */
 387     next_state = ISM_Waiting;
 388
 389   if (oi->type == OSPF_IFTYPE_NBMA)
 390     ospf_nbr_nbma_if_update (oi->ospf, oi);
 391
 392   /*  ospf_ism_event (t); */
 393   return next_state;
 394 }
 395
 396 int
 397 ism_loop_ind (struct ospf_interface *oi)
 398 {
 399   int ret = 0;
 400
 401   /* call ism_interface_down. */
 402   /* ret = ism_interface_down (oi); */
 403
 404   return ret;
 405 }
 406
 407 /* Interface down event handler. */
 408 int
 409 ism_interface_down (struct ospf_interface *oi)
 410 {
 411   ospf_if_cleanup (oi);
 412   return 0;
 413 }
 414
 415
 416 int
 417 ism_backup_seen (struct ospf_interface *oi)
 418 {
 419   return ospf_dr_election (oi);
 420 }
 421
 422 int
 423 ism_wait_timer (struct ospf_interface *oi)
 424 {
 425   return ospf_dr_election (oi);
 426 }
 427
 428 int
 429 ism_neighbor_change (struct ospf_interface *oi)
 430 {
 431   return ospf_dr_election (oi);
 432 }
 433
 434 int
 435 ism_ignore (struct ospf_interface *oi)
 436 {
 437   if (IS_DEBUG_OSPF (ism, ISM_EVENTS))
 438     zlog (NULL, LOG_DEBUG, "ISM[%s]: ism_ignore called", IF_NAME (oi));
 439
 440   return 0;
 441 }
 442
 443 /* Interface State Machine */
 444 struct {
 445   int (*func) ();
 446   int next_state;
 447 } ISM [OSPF_ISM_STATE_MAX][OSPF_ISM_EVENT_MAX] =
 448 {
 449   {
 450     /* DependUpon: dummy state. */
 451     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 452     { ism_ignore,          ISM_DependUpon },    /* InterfaceUp    */
 453     { ism_ignore,          ISM_DependUpon },    /* WaitTimer      */
 454     { ism_ignore,          ISM_DependUpon },    /* BackupSeen     */
 455     { ism_ignore,          ISM_DependUpon },    /* NeighborChange */
 456     { ism_ignore,          ISM_DependUpon },    /* LoopInd        */
 457     { ism_ignore,          ISM_DependUpon },    /* UnloopInd      */
 458     { ism_ignore,          ISM_DependUpon },    /* InterfaceDown  */
 459   },
 460   {
 461     /* Down:*/
 462     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 463     { ism_interface_up,    ISM_DependUpon },    /* InterfaceUp    */
 464     { ism_ignore,          ISM_Down },          /* WaitTimer      */
 465     { ism_ignore,          ISM_Down },          /* BackupSeen     */
 466     { ism_ignore,          ISM_Down },          /* NeighborChange */
 467     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 468     { ism_ignore,          ISM_Down },          /* UnloopInd      */
 469     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 470   },
 471   {
 472     /* Loopback: */
 473     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 474     { ism_ignore,          ISM_Loopback },      /* InterfaceUp    */
 475     { ism_ignore,          ISM_Loopback },      /* WaitTimer      */
 476     { ism_ignore,          ISM_Loopback },      /* BackupSeen     */
 477     { ism_ignore,          ISM_Loopback },      /* NeighborChange */
 478     { ism_ignore,          ISM_Loopback },      /* LoopInd        */
 479     { ism_ignore,          ISM_Down },          /* UnloopInd      */
 480     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 481   },
 482   {
 483     /* Waiting: */
 484     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 485     { ism_ignore,          ISM_Waiting },       /* InterfaceUp    */
 486     { ism_wait_timer,      ISM_DependUpon },    /* WaitTimer      */
 487     { ism_backup_seen,     ISM_DependUpon },    /* BackupSeen     */
 488     { ism_ignore,          ISM_Waiting },       /* NeighborChange */
 489     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 490     { ism_ignore,          ISM_Waiting },       /* UnloopInd      */
 491     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 492   },
 493   {
 494     /* Point-to-Point: */
 495     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 496     { ism_ignore,          ISM_PointToPoint },  /* InterfaceUp    */
 497     { ism_ignore,          ISM_PointToPoint },  /* WaitTimer      */
 498     { ism_ignore,          ISM_PointToPoint },  /* BackupSeen     */
 499     { ism_ignore,          ISM_PointToPoint },  /* NeighborChange */
 500     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 501     { ism_ignore,          ISM_PointToPoint },  /* UnloopInd      */
 502     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 503   },
 504   {
 505     /* DROther: */
 506     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 507     { ism_ignore,          ISM_DROther },       /* InterfaceUp    */
 508     { ism_ignore,          ISM_DROther },       /* WaitTimer      */
 509     { ism_ignore,          ISM_DROther },       /* BackupSeen     */
 510     { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
 511     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 512     { ism_ignore,          ISM_DROther },       /* UnloopInd      */
 513     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 514   },
 515   {
 516     /* Backup: */
 517     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 518     { ism_ignore,          ISM_Backup },        /* InterfaceUp    */
 519     { ism_ignore,          ISM_Backup },        /* WaitTimer      */
 520     { ism_ignore,          ISM_Backup },        /* BackupSeen     */
 521     { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
 522     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 523     { ism_ignore,          ISM_Backup },        /* UnloopInd      */
 524     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 525   },
 526   {
 527     /* DR: */
 528     { ism_ignore,          ISM_DependUpon },    /* NoEvent        */
 529     { ism_ignore,          ISM_DR },            /* InterfaceUp    */
 530     { ism_ignore,          ISM_DR },            /* WaitTimer      */
 531     { ism_ignore,          ISM_DR },            /* BackupSeen     */
 532     { ism_neighbor_change, ISM_DependUpon },    /* NeighborChange */
 533     { ism_loop_ind,        ISM_Loopback },      /* LoopInd        */
 534     { ism_ignore,          ISM_DR },            /* UnloopInd      */
 535     { ism_interface_down,  ISM_Down },          /* InterfaceDown  */
 536   },
 537 };
 538
 539 const static char *ospf_ism_event_str[] =
 540 {
 541   "NoEvent",
 542   "InterfaceUp",
 543   "WaitTimer",
 544   "BackupSeen",
 545   "NeighborChange",
 546   "LoopInd",
 547   "UnLoopInd",
 548   "InterfaceDown",
 549 };
 550
 551 void
 552 ism_change_state (struct ospf_interface *oi, int state)
 553 {
 554   int old_state;
 555   struct ospf_lsa *lsa;
 556
 557   /* Logging change of state. */
 558   if (IS_DEBUG_OSPF (ism, ISM_STATUS))
 559     zlog (NULL, LOG_DEBUG, "ISM[%s]: State change %s -> %s", IF_NAME (oi),
 560           LOOKUP (ospf_ism_state_msg, oi->state),
 561           LOOKUP (ospf_ism_state_msg, state));
 562
 563   old_state = oi->state;
 564   oi->state = state;
 565   oi->state_change++;
 566
 567   /* Set multicast memberships appropriately for new state. */
 568   ospf_if_set_multicast(oi);
 569
 570   if (old_state == ISM_Down || state == ISM_Down)
 571     ospf_check_abr_status (oi->ospf);
 572
 573   /* Originate router-LSA. */
 574   if (oi->area)
 575     {
 576       if (state == ISM_Down)
 577         {
 578           if (oi->area->act_ints > 0)
 579             oi->area->act_ints--;
 580         }
 581       else if (old_state == ISM_Down)
 582         oi->area->act_ints++;
 583
 584       /* schedule router-LSA originate. */
 585       ospf_router_lsa_timer_add (oi->area);
 586     }
 587
 588   /* Originate network-LSA. */
 589   if (old_state != ISM_DR && state == ISM_DR)
 590     ospf_network_lsa_timer_add (oi);
 591   else if (old_state == ISM_DR && state != ISM_DR)
 592     {
 593       /* Free self originated network LSA. */
 594       lsa = oi->network_lsa_self;
 595       if (lsa)
 596         {
 597           ospf_lsa_flush_area (lsa, oi->area);
 598           OSPF_TIMER_OFF (oi->t_network_lsa_self);
 599         }
 600
 601       ospf_lsa_unlock (oi->network_lsa_self);
 602       oi->network_lsa_self = NULL;
 603     }
 604
 605 #ifdef HAVE_OPAQUE_LSA
 606   ospf_opaque_ism_change (oi, old_state);
 607 #endif /* HAVE_OPAQUE_LSA */
 608
 609   /* Check area border status.  */
 610   ospf_check_abr_status (oi->ospf);
 611 }
 612
 613 /* Execute ISM event process. */
 614 int
 615 ospf_ism_event (struct thread *thread)
 616 {
 617   int event;
 618   int next_state;
 619   struct ospf_interface *oi;
 620
 621   oi = THREAD_ARG (thread);
 622   event = THREAD_VAL (thread);
 623
 624   /* Call function. */
 625   next_state = (*(ISM [oi->state][event].func))(oi);
 626
 627   if (! next_state)
 628     next_state = ISM [oi->state][event].next_state;
 629
 630   if (IS_DEBUG_OSPF (ism, ISM_EVENTS))
 631     zlog (NULL, LOG_DEBUG, "ISM[%s]: %s (%s)", IF_NAME (oi),
 632           LOOKUP (ospf_ism_state_msg, oi->state),
 633           ospf_ism_event_str[event]);
 634
 635   /* If state is changed. */
 636   if (next_state != oi->state)
 637     ism_change_state (oi, next_state);
 638
 639   /* Make sure timer is set. */
 640   ism_timer_set (oi);
 641
 642   return 0;
 643 }
 644