ospfd/ospf_nsm.c

   1 /*
   2  * OSPF version 2  Neighbor 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 "memory.h"
  28 #include "hash.h"
  29 #include "linklist.h"
  30 #include "prefix.h"
  31 #include "if.h"
  32 #include "table.h"
  33 #include "stream.h"
  34 #include "table.h"
  35 #include "log.h"
  36
  37 #include "ospfd/ospfd.h"
  38 #include "ospfd/ospf_interface.h"
  39 #include "ospfd/ospf_ism.h"
  40 #include "ospfd/ospf_asbr.h"
  41 #include "ospfd/ospf_lsa.h"
  42 #include "ospfd/ospf_lsdb.h"
  43 #include "ospfd/ospf_neighbor.h"
  44 #include "ospfd/ospf_nsm.h"
  45 #include "ospfd/ospf_network.h"
  46 #include "ospfd/ospf_packet.h"
  47 #include "ospfd/ospf_dump.h"
  48 #include "ospfd/ospf_flood.h"
  49 #include "ospfd/ospf_abr.h"
  50 #include "ospfd/ospf_snmp.h"
  51
  52 static void nsm_clear_adj (struct ospf_neighbor *);
  53
  54 /* OSPF NSM Timer functions. */
  55 static int
  56 ospf_inactivity_timer (struct thread *thread)
  57 {
  58   struct ospf_neighbor *nbr;
  59
  60   nbr = THREAD_ARG (thread);
  61   nbr->t_inactivity = NULL;
  62
  63   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  64     zlog (NULL, LOG_DEBUG, "NSM[%s:%s]: Timer (Inactivity timer expire)",
  65           IF_NAME (nbr->oi), inet_ntoa (nbr->router_id));
  66
  67   OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_InactivityTimer);
  68
  69   return 0;
  70 }
  71
  72 static int
  73 ospf_db_desc_timer (struct thread *thread)
  74 {
  75   struct ospf_neighbor *nbr;
  76
  77   nbr = THREAD_ARG (thread);
  78   nbr->t_db_desc = NULL;
  79
  80   if (IS_DEBUG_OSPF (nsm, NSM_TIMERS))
  81     zlog (NULL, LOG_DEBUG, "NSM[%s:%s]: Timer (DD Retransmit timer expire)",
  82           IF_NAME (nbr->oi), inet_ntoa (nbr->src));
  83
  84   /* resent last send DD packet. */
  85   assert (nbr->last_send);
  86   ospf_db_desc_resend (nbr);
  87
  88   /* DD Retransmit timer set. */
  89   OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
  90
  91   return 0;
  92 }
  93
  94 /* Hook function called after ospf NSM event is occured.
  95  *
  96  * Set/clear any timers whose condition is implicit to the neighbour
  97  * state. There may be other timers which are set/unset according to other
  98  * state.
  99  *
 100  * We rely on this function to properly clear timers in lower states,
 101  * particularly before deleting a neighbour.
 102  */
 103 static void
 104 nsm_timer_set (struct ospf_neighbor *nbr)
 105 {
 106   switch (nbr->state)
 107     {
 108     case NSM_Deleted:
 109     case NSM_Down:
 110       OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 111       OSPF_NSM_TIMER_OFF (nbr->t_hello_reply);
 112     case NSM_Attempt:
 113     case NSM_Init:
 114     case NSM_TwoWay:
 115       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 116       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 117       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 118       break;
 119     case NSM_ExStart:
 120       OSPF_NSM_TIMER_ON (nbr->t_db_desc, ospf_db_desc_timer, nbr->v_db_desc);
 121       OSPF_NSM_TIMER_OFF (nbr->t_ls_upd);
 122       OSPF_NSM_TIMER_OFF (nbr->t_ls_req);
 123       break;
 124     case NSM_Exchange:
 125       OSPF_NSM_TIMER_ON (nbr->t_ls_upd, ospf_ls_upd_timer, nbr->v_ls_upd);
 126       if (!IS_SET_DD_MS (nbr->dd_flags))
 127         OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 128       break;
 129     case NSM_Loading:
 130     case NSM_Full:
 131     default:
 132       OSPF_NSM_TIMER_OFF (nbr->t_db_desc);
 133       break;
 134     }
 135 }
 136
 137 /* 10.4 of RFC2328, indicate whether an adjacency is appropriate with
 138  * the given neighbour
 139  */
 140 static int
 141 nsm_should_adj (struct ospf_neighbor *nbr)
 142 {
 143   struct ospf_interface *oi = nbr->oi;
 144
 145       /* These network types must always form adjacencies. */
 146   if (oi->type == OSPF_IFTYPE_POINTOPOINT
 147       || oi->type == OSPF_IFTYPE_POINTOMULTIPOINT
 148       || oi->type == OSPF_IFTYPE_VIRTUALLINK
 149       /* Router itself is the DRouter or the BDRouter. */
 150       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &DR (oi))
 151       || IPV4_ADDR_SAME (&oi->address->u.prefix4, &BDR (oi))
 152       /* Neighboring Router is the DRouter or the BDRouter. */
 153       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &DR (oi))
 154       || IPV4_ADDR_SAME (&nbr->address.u.prefix4, &BDR (oi)))
 155     return 1;
 156
 157   return 0;
 158 }
 159
 160 /* OSPF NSM functions. */
 161 static int
 162 nsm_packet_received (struct ospf_neighbor *nbr)
 163 {
 164   /* Start or Restart Inactivity Timer. */
 165   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 166
 167   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 168                      nbr->v_inactivity);
 169
 170   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma)
 171     OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 172
 173   return 0;
 174 }
 175
 176 static int
 177 nsm_start (struct ospf_neighbor *nbr)
 178 {
 179   if (nbr->nbr_nbma)
 180       OSPF_POLL_TIMER_OFF (nbr->nbr_nbma->t_poll);
 181
 182   OSPF_NSM_TIMER_OFF (nbr->t_inactivity);
 183
 184   OSPF_NSM_TIMER_ON (nbr->t_inactivity, ospf_inactivity_timer,
 185                      nbr->v_inactivity);
 186
 187   return 0;
 188 }
 189
 190 static int
 191 nsm_twoway_received (struct ospf_neighbor *nbr)
 192 {
 193   return (nsm_should_adj (nbr) ? NSM_ExStart : NSM_TwoWay);
 194 }
 195
 196 int
 197 ospf_db_summary_count (struct ospf_neighbor *nbr)
 198 {
 199   return ospf_lsdb_count_all (&nbr->db_sum);
 200 }
 201
 202 int
 203 ospf_db_summary_isempty (struct ospf_neighbor *nbr)
 204 {
 205   return ospf_lsdb_isempty (&nbr->db_sum);
 206 }
 207
 208 static int
 209 ospf_db_summary_add (struct ospf_neighbor *nbr, struct ospf_lsa *lsa)
 210 {
 211   switch (lsa->data->type)
 212     {
 213     case OSPF_OPAQUE_LINK_LSA:
 214       /* Exclude type-9 LSAs that does not have the same "oi" with "nbr". */
 215       if (nbr->oi && ospf_if_exists (lsa->oi) != nbr->oi)
 216           return 0;
 217       break;
 218     case OSPF_OPAQUE_AREA_LSA:
 219       /*
 220        * It is assured by the caller function "nsm_negotiation_done()"
 221        * that every given LSA belongs to the same area with "nbr".
 222        */
 223       break;
 224     case OSPF_OPAQUE_AS_LSA:
 225     default:
 226       break;
 227     }
 228
 229   /* Stay away from any Local Translated Type-7 LSAs */
 230   if (CHECK_FLAG (lsa->flags, OSPF_LSA_LOCAL_XLT))
 231     return 0;
 232
 233   if (IS_LSA_MAXAGE (lsa))
 234     ospf_ls_retransmit_add (nbr, lsa);
 235   else
 236     ospf_lsdb_add (&nbr->db_sum, lsa);
 237
 238   return 0;
 239 }
 240
 241 void
 242 ospf_db_summary_clear (struct ospf_neighbor *nbr)
 243 {
 244   struct ospf_lsdb *lsdb;
 245   int i;
 246
 247   lsdb = &nbr->db_sum;
 248   for (i = OSPF_MIN_LSA; i < OSPF_MAX_LSA; i++)
 249     {
 250       struct route_table *table = lsdb->type[i].db;
 251       struct route_node *rn;
 252
 253       for (rn = route_top (table); rn; rn = route_next (rn))
 254         if (rn->info)
 255           ospf_lsdb_delete (&nbr->db_sum, rn->info);
 256     }
 257 }
 258
 259
 260
 261 /* The area link state database consists of the router-LSAs,
 262    network-LSAs and summary-LSAs contained in the area structure,
 263    along with the AS-external-LSAs contained in the global structure.
 264    AS-external-LSAs are omitted from a virtual neighbor's Database
 265    summary list.  AS-external-LSAs are omitted from the Database
 266    summary list if the area has been configured as a stub. */
 267 static int
 268 nsm_negotiation_done (struct ospf_neighbor *nbr)
 269 {
 270   struct ospf_area *area = nbr->oi->area;
 271   struct ospf_lsa *lsa;
 272   struct route_node *rn;
 273
 274   LSDB_LOOP (ROUTER_LSDB (area), rn, lsa)
 275     ospf_db_summary_add (nbr, lsa);
 276   LSDB_LOOP (NETWORK_LSDB (area), rn, lsa)
 277     ospf_db_summary_add (nbr, lsa);
 278   LSDB_LOOP (SUMMARY_LSDB (area), rn, lsa)
 279     ospf_db_summary_add (nbr, lsa);
 280   LSDB_LOOP (ASBR_SUMMARY_LSDB (area), rn, lsa)
 281     ospf_db_summary_add (nbr, lsa);
 282
 283   /* Process only if the neighbor is opaque capable. */
 284   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 285     {
 286       LSDB_LOOP (OPAQUE_LINK_LSDB (area), rn, lsa)
 287         ospf_db_summary_add (nbr, lsa);
 288       LSDB_LOOP (OPAQUE_AREA_LSDB (area), rn, lsa)
 289         ospf_db_summary_add (nbr, lsa);
 290     }
 291
 292   if (CHECK_FLAG (nbr->options, OSPF_OPTION_NP))
 293     {
 294       LSDB_LOOP (NSSA_LSDB (area), rn, lsa)
 295         ospf_db_summary_add (nbr, lsa);
 296     }
 297
 298   if (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 299       && area->external_routing == OSPF_AREA_DEFAULT)
 300     LSDB_LOOP (EXTERNAL_LSDB (nbr->oi->ospf), rn, lsa)
 301       ospf_db_summary_add (nbr, lsa);
 302
 303   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O)
 304       && (nbr->oi->type != OSPF_IFTYPE_VIRTUALLINK
 305           && area->external_routing == OSPF_AREA_DEFAULT))
 306     LSDB_LOOP (OPAQUE_AS_LSDB (nbr->oi->ospf), rn, lsa)
 307       ospf_db_summary_add (nbr, lsa);
 308
 309   /* Send Link State Request. */
 310   if (nbr->t_ls_req == NULL)
 311     ospf_ls_req_send (nbr);
 312
 313   return 0;
 314 }
 315
 316 static int
 317 nsm_exchange_done (struct ospf_neighbor *nbr)
 318 {
 319   if (ospf_ls_request_isempty (nbr))
 320     return NSM_Full;
 321
 322   if (nbr->t_ls_req == NULL)
 323     ospf_ls_req_send (nbr);
 324
 325   return NSM_Loading;
 326 }
 327
 328 static int
 329 nsm_adj_ok (struct ospf_neighbor *nbr)
 330 {
 331   int next_state = nbr->state;
 332   int adj = nsm_should_adj (nbr);
 333
 334   if (nbr->state == NSM_TwoWay && adj == 1)
 335     next_state = NSM_ExStart;
 336   else if (nbr->state >= NSM_ExStart && adj == 0)
 337     next_state = NSM_TwoWay;
 338
 339   return next_state;
 340 }
 341
 342 /* Clear adjacency related state for a neighbour, intended where nbr
 343  * transitions from > ExStart (i.e. a Full or forming adjacency)
 344  * to <= ExStart.
 345  */
 346 static void
 347 nsm_clear_adj (struct ospf_neighbor *nbr)
 348 {
 349   /* Clear Database Summary list. */
 350   if (!ospf_db_summary_isempty (nbr))
 351     ospf_db_summary_clear (nbr);
 352
 353   /* Clear Link State Request list. */
 354   if (!ospf_ls_request_isempty (nbr))
 355     ospf_ls_request_delete_all (nbr);
 356
 357   /* Clear Link State Retransmission list. */
 358   if (!ospf_ls_retransmit_isempty (nbr))
 359     ospf_ls_retransmit_clear (nbr);
 360
 361   if (CHECK_FLAG (nbr->options, OSPF_OPTION_O))
 362     UNSET_FLAG (nbr->options, OSPF_OPTION_O);
 363 }
 364
 365 static int
 366 nsm_kill_nbr (struct ospf_neighbor *nbr)
 367 {
 368   /* killing nbr_self is invalid */
 369   if (nbr == nbr->oi->nbr_self)
 370     {
 371       assert (nbr != nbr->oi->nbr_self);
 372       return 0;
 373     }
 374
 375   if (nbr->oi->type == OSPF_IFTYPE_NBMA && nbr->nbr_nbma != NULL)
 376     {
 377       struct ospf_nbr_nbma *nbr_nbma = nbr->nbr_nbma;
 378
 379       nbr_nbma->nbr = NULL;
 380       nbr_nbma->state_change = nbr->state_change;
 381
 382       nbr->nbr_nbma = NULL;
 383
 384       OSPF_POLL_TIMER_ON (nbr_nbma->t_poll, ospf_poll_timer,
 385                           nbr_nbma->v_poll);
 386
 387       if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 388         zlog_debug ("NSM[%s:%s]: Down (PollIntervalTimer scheduled)",
 389                    IF_NAME (nbr->oi), inet_ntoa (nbr->address.u.prefix4));
 390     }
 391
 392   return 0;
 393 }
 394
 395 /* Neighbor State Machine */
 396 struct {
 397   int (*func) (struct ospf_neighbor *);
 398   int next_state;
 399 } NSM [OSPF_NSM_STATE_MAX][OSPF_NSM_EVENT_MAX] =
 400 {
 401   {
 402     /* DependUpon: dummy state. */
 403     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 404     { NULL,                    NSM_DependUpon }, /* PacketReceived    */
 405     { NULL,                    NSM_DependUpon }, /* Start             */
 406     { NULL,                    NSM_DependUpon }, /* 2-WayReceived     */
 407     { NULL,                    NSM_DependUpon }, /* NegotiationDone   */
 408     { NULL,                    NSM_DependUpon }, /* ExchangeDone      */
 409     { NULL,                    NSM_DependUpon }, /* BadLSReq          */
 410     { NULL,                    NSM_DependUpon }, /* LoadingDone       */
 411     { NULL,                    NSM_DependUpon }, /* AdjOK?            */
 412     { NULL,                    NSM_DependUpon }, /* SeqNumberMismatch */
 413     { NULL,                    NSM_DependUpon }, /* 1-WayReceived     */
 414     { NULL,                    NSM_DependUpon }, /* KillNbr           */
 415     { NULL,                    NSM_DependUpon }, /* InactivityTimer   */
 416     { NULL,                    NSM_DependUpon }, /* LLDown            */
 417   },
 418   {
 419     /* Deleted: dummy state. */
 420     { NULL,                    NSM_Deleted    }, /* NoEvent           */
 421     { NULL,                    NSM_Deleted    }, /* PacketReceived    */
 422     { NULL,                    NSM_Deleted    }, /* Start             */
 423     { NULL,                    NSM_Deleted    }, /* 2-WayReceived     */
 424     { NULL,                    NSM_Deleted    }, /* NegotiationDone   */
 425     { NULL,                    NSM_Deleted    }, /* ExchangeDone      */
 426     { NULL,                    NSM_Deleted    }, /* BadLSReq          */
 427     { NULL,                    NSM_Deleted    }, /* LoadingDone       */
 428     { NULL,                    NSM_Deleted    }, /* AdjOK?            */
 429     { NULL,                    NSM_Deleted    }, /* SeqNumberMismatch */
 430     { NULL,                    NSM_Deleted    }, /* 1-WayReceived     */
 431     { NULL,                    NSM_Deleted    }, /* KillNbr           */
 432     { NULL,                    NSM_Deleted    }, /* InactivityTimer   */
 433     { NULL,                    NSM_Deleted    }, /* LLDown            */
 434   },
 435   {
 436     /* Down: */
 437     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 438     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 439     { nsm_start,               NSM_Attempt    }, /* Start             */
 440     { NULL,                    NSM_Down       }, /* 2-WayReceived     */
 441     { NULL,                    NSM_Down       }, /* NegotiationDone   */
 442     { NULL,                    NSM_Down       }, /* ExchangeDone      */
 443     { NULL,                    NSM_Down       }, /* BadLSReq          */
 444     { NULL,                    NSM_Down       }, /* LoadingDone       */
 445     { NULL,                    NSM_Down       }, /* AdjOK?            */
 446     { NULL,                    NSM_Down       }, /* SeqNumberMismatch */
 447     { NULL,                    NSM_Down       }, /* 1-WayReceived     */
 448     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 449     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 450     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 451   },
 452   {
 453     /* Attempt: */
 454     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 455     { nsm_packet_received,     NSM_Init       }, /* PacketReceived    */
 456     { NULL,                    NSM_Attempt    }, /* Start             */
 457     { NULL,                    NSM_Attempt    }, /* 2-WayReceived     */
 458     { NULL,                    NSM_Attempt    }, /* NegotiationDone   */
 459     { NULL,                    NSM_Attempt    }, /* ExchangeDone      */
 460     { NULL,                    NSM_Attempt    }, /* BadLSReq          */
 461     { NULL,                    NSM_Attempt    }, /* LoadingDone       */
 462     { NULL,                    NSM_Attempt    }, /* AdjOK?            */
 463     { NULL,                    NSM_Attempt    }, /* SeqNumberMismatch */
 464     { NULL,                    NSM_Attempt    }, /* 1-WayReceived     */
 465     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 466     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 467     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 468   },
 469   {
 470     /* Init: */
 471     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 472     { nsm_packet_received,     NSM_Init      }, /* PacketReceived    */
 473     { NULL,                    NSM_Init       }, /* Start             */
 474     { nsm_twoway_received,     NSM_DependUpon }, /* 2-WayReceived     */
 475     { NULL,                    NSM_Init       }, /* NegotiationDone   */
 476     { NULL,                    NSM_Init       }, /* ExchangeDone      */
 477     { NULL,                    NSM_Init       }, /* BadLSReq          */
 478     { NULL,                    NSM_Init       }, /* LoadingDone       */
 479     { NULL,                    NSM_Init       }, /* AdjOK?            */
 480     { NULL,                    NSM_Init       }, /* SeqNumberMismatch */
 481     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 482     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 483     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 484     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 485   },
 486   {
 487     /* 2-Way: */
 488     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 489     { nsm_packet_received,     NSM_TwoWay     }, /* HelloReceived     */
 490     { NULL,                    NSM_TwoWay     }, /* Start             */
 491     { NULL,                    NSM_TwoWay     }, /* 2-WayReceived     */
 492     { NULL,                    NSM_TwoWay     }, /* NegotiationDone   */
 493     { NULL,                    NSM_TwoWay     }, /* ExchangeDone      */
 494     { NULL,                    NSM_TwoWay     }, /* BadLSReq          */
 495     { NULL,                    NSM_TwoWay     }, /* LoadingDone       */
 496     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 497     { NULL,                    NSM_TwoWay     }, /* SeqNumberMismatch */
 498     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 499     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 500     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 501     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 502   },
 503   {
 504     /* ExStart: */
 505     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 506     { nsm_packet_received,     NSM_ExStart    }, /* PacaketReceived   */
 507     { NULL,                    NSM_ExStart    }, /* Start             */
 508     { NULL,                    NSM_ExStart    }, /* 2-WayReceived     */
 509     { nsm_negotiation_done,    NSM_Exchange   }, /* NegotiationDone   */
 510     { NULL,                    NSM_ExStart    }, /* ExchangeDone      */
 511     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 512     { NULL,                    NSM_ExStart    }, /* LoadingDone       */
 513     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 514     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 515     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 516     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 517     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 518     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 519   },
 520   {
 521     /* Exchange: */
 522     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 523     { nsm_packet_received,     NSM_Exchange   }, /* PacketReceived    */
 524     { NULL,                    NSM_Exchange   }, /* Start             */
 525     { NULL,                    NSM_Exchange   }, /* 2-WayReceived     */
 526     { NULL,                    NSM_Exchange   }, /* NegotiationDone   */
 527     { nsm_exchange_done,       NSM_DependUpon }, /* ExchangeDone      */
 528     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 529     { NULL,                    NSM_Exchange   }, /* LoadingDone       */
 530     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 531     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 532     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 533     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 534     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 535     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 536   },
 537   {
 538     /* Loading: */
 539     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 540     { nsm_packet_received,     NSM_Loading    }, /* PacketReceived    */
 541     { NULL,                    NSM_Loading    }, /* Start             */
 542     { NULL,                    NSM_Loading    }, /* 2-WayReceived     */
 543     { NULL,                    NSM_Loading    }, /* NegotiationDone   */
 544     { NULL,                    NSM_Loading    }, /* ExchangeDone      */
 545     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 546     { NULL,                    NSM_Full       }, /* LoadingDone       */
 547     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 548     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 549     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 550     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 551     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 552     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 553   },
 554   { /* Full: */
 555     { NULL,                    NSM_DependUpon }, /* NoEvent           */
 556     { nsm_packet_received,     NSM_Full       }, /* PacketReceived    */
 557     { NULL,                    NSM_Full       }, /* Start             */
 558     { NULL,                    NSM_Full       }, /* 2-WayReceived     */
 559     { NULL,                    NSM_Full       }, /* NegotiationDone   */
 560     { NULL,                    NSM_Full       }, /* ExchangeDone      */
 561     { NULL,                    NSM_ExStart    }, /* BadLSReq          */
 562     { NULL,                    NSM_Full       }, /* LoadingDone       */
 563     { nsm_adj_ok,              NSM_DependUpon }, /* AdjOK?            */
 564     { NULL,                    NSM_ExStart    }, /* SeqNumberMismatch */
 565     { NULL,                    NSM_Init       }, /* 1-WayReceived     */
 566     { nsm_kill_nbr,            NSM_Deleted    }, /* KillNbr           */
 567     { nsm_kill_nbr,            NSM_Deleted    }, /* InactivityTimer   */
 568     { nsm_kill_nbr,            NSM_Deleted    }, /* LLDown            */
 569   },
 570 };
 571
 572 static const char *ospf_nsm_event_str[] =
 573 {
 574   "NoEvent",
 575   "PacketReceived",
 576   "Start",
 577   "2-WayReceived",
 578   "NegotiationDone",
 579   "ExchangeDone",
 580   "BadLSReq",
 581   "LoadingDone",
 582   "AdjOK?",
 583   "SeqNumberMismatch",
 584   "1-WayReceived",
 585   "KillNbr",
 586   "InactivityTimer",
 587   "LLDown",
 588 };
 589
 590 static void
 591 nsm_notice_state_change (struct ospf_neighbor *nbr, int next_state, int event)
 592 {
 593   /* Logging change of status. */
 594   if (IS_DEBUG_OSPF (nsm, NSM_STATUS))
 595     zlog_debug ("NSM[%s:%s]: State change %s -> %s (%s)",
 596                IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 597                LOOKUP (ospf_nsm_state_msg, nbr->state),
 598                LOOKUP (ospf_nsm_state_msg, next_state),
 599                ospf_nsm_event_str [event]);
 600
 601   /* Optionally notify about adjacency changes */
 602   if (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_CHANGES) &&
 603       (CHECK_FLAG(nbr->oi->ospf->config, OSPF_LOG_ADJACENCY_DETAIL) ||
 604        (next_state == NSM_Full) || (next_state < nbr->state)))
 605     zlog_notice("AdjChg: Nbr %s on %s: %s -> %s (%s)",
 606                 inet_ntoa (nbr->router_id), IF_NAME (nbr->oi),
 607                 LOOKUP (ospf_nsm_state_msg, nbr->state),
 608                 LOOKUP (ospf_nsm_state_msg, next_state),
 609                 ospf_nsm_event_str [event]);
 610
 611   /* Advance in NSM */
 612   if (next_state > nbr->state)
 613     nbr->ts_last_progress = recent_relative_time ();
 614   else /* regression in NSM */
 615     {
 616       nbr->ts_last_regress = recent_relative_time ();
 617       nbr->last_regress_str = ospf_nsm_event_str [event];
 618     }
 619
 620 }
 621
 622 static void
 623 nsm_change_state (struct ospf_neighbor *nbr, int state)
 624 {
 625   struct ospf_interface *oi = nbr->oi;
 626   struct ospf_area *vl_area = NULL;
 627   u_char old_state;
 628   int x;
 629   int force = 1;
 630
 631   /* Preserve old status. */
 632   old_state = nbr->state;
 633
 634   /* Change to new status. */
 635   nbr->state = state;
 636
 637   /* Statistics. */
 638   nbr->state_change++;
 639
 640   if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 641     vl_area = ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 642
 643   /* Generate NeighborChange ISM event.
 644    *
 645    * In response to NeighborChange, DR election is rerun. The information
 646    * from the election process is required by the router-lsa construction.
 647    *
 648    * Therefore, trigger the event prior to refreshing the LSAs. */
 649   switch (oi->state) {
 650   case ISM_DROther:
 651   case ISM_Backup:
 652   case ISM_DR:
 653     if ((old_state < NSM_TwoWay && state >= NSM_TwoWay) ||
 654         (old_state >= NSM_TwoWay && state < NSM_TwoWay))
 655       OSPF_ISM_EVENT_EXECUTE (oi, ISM_NeighborChange);
 656     break;
 657   default:
 658     /* ISM_PointToPoint -> ISM_Down, ISM_Loopback -> ISM_Down, etc. */
 659     break;
 660   }
 661
 662   /* One of the neighboring routers changes to/from the FULL state. */
 663   if ((old_state != NSM_Full && state == NSM_Full) ||
 664       (old_state == NSM_Full && state != NSM_Full))
 665     {
 666       if (state == NSM_Full)
 667         {
 668           oi->full_nbrs++;
 669           oi->area->full_nbrs++;
 670
 671           ospf_check_abr_status (oi->ospf);
 672
 673           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 674             if (++vl_area->full_vls == 1)
 675               ospf_schedule_abr_task (oi->ospf);
 676
 677           /* kevinm: refresh any redistributions */
 678           for (x = ZEBRA_ROUTE_SYSTEM; x < ZEBRA_ROUTE_MAX; x++)
 679             {
 680               if (x == ZEBRA_ROUTE_OSPF || x == ZEBRA_ROUTE_OSPF6)
 681                 continue;
 682               ospf_external_lsa_refresh_type (oi->ospf, x, force);
 683             }
 684           /* XXX: Clearly some thing is wrong with refresh of external LSAs
 685            * this added to hack around defaults not refreshing after a timer
 686            * jump.
 687            */
 688           ospf_external_lsa_refresh_default (oi->ospf);
 689         }
 690       else
 691         {
 692           oi->full_nbrs--;
 693           oi->area->full_nbrs--;
 694
 695           ospf_check_abr_status (oi->ospf);
 696
 697           if (oi->type == OSPF_IFTYPE_VIRTUALLINK && vl_area)
 698             if (vl_area->full_vls > 0)
 699               if (--vl_area->full_vls == 0)
 700                 ospf_schedule_abr_task (oi->ospf);
 701         }
 702
 703       zlog_info ("nsm_change_state(%s, %s -> %s): "
 704                  "scheduling new router-LSA origination",
 705                  inet_ntoa (nbr->router_id),
 706                  LOOKUP(ospf_nsm_state_msg, old_state),
 707                  LOOKUP(ospf_nsm_state_msg, state));
 708
 709       ospf_router_lsa_update_area (oi->area);
 710
 711       if (oi->type == OSPF_IFTYPE_VIRTUALLINK)
 712         {
 713           struct ospf_area *vl_area =
 714             ospf_area_lookup_by_area_id (oi->ospf, oi->vl_data->vl_area_id);
 715
 716           if (vl_area)
 717             ospf_router_lsa_update_area (vl_area);
 718         }
 719
 720       /* Originate network-LSA. */
 721       if (oi->state == ISM_DR)
 722         {
 723           if (oi->network_lsa_self && oi->full_nbrs == 0)
 724             {
 725               ospf_lsa_flush_area (oi->network_lsa_self, oi->area);
 726               ospf_lsa_unlock (&oi->network_lsa_self);
 727               oi->network_lsa_self = NULL;
 728             }
 729           else
 730             ospf_network_lsa_update (oi);
 731         }
 732     }
 733
 734   ospf_opaque_nsm_change (nbr, old_state);
 735
 736   /* State changes from > ExStart to <= ExStart should clear any Exchange
 737    * or Full/LSA Update related lists and state.
 738    * Potential causal events: BadLSReq, SeqNumberMismatch, AdjOK?
 739    */
 740   if ((old_state > NSM_ExStart) && (state <= NSM_ExStart))
 741     nsm_clear_adj (nbr);
 742
 743   /* Start DD exchange protocol */
 744   if (state == NSM_ExStart)
 745     {
 746       if (nbr->dd_seqnum == 0)
 747         nbr->dd_seqnum = quagga_time (NULL);
 748       else
 749         nbr->dd_seqnum++;
 750
 751       nbr->dd_flags = OSPF_DD_FLAG_I|OSPF_DD_FLAG_M|OSPF_DD_FLAG_MS;
 752       ospf_db_desc_send (nbr);
 753     }
 754
 755   /* clear cryptographic sequence number */
 756   if (state == NSM_Down)
 757     nbr->crypt_seqnum = 0;
 758
 759   /* Preserve old status? */
 760 }
 761
 762 /* Execute NSM event process. */
 763 int
 764 ospf_nsm_event (struct thread *thread)
 765 {
 766   int event;
 767   int next_state;
 768   struct ospf_neighbor *nbr;
 769
 770   nbr = THREAD_ARG (thread);
 771   event = THREAD_VAL (thread);
 772
 773   if (IS_DEBUG_OSPF (nsm, NSM_EVENTS))
 774     zlog_debug ("NSM[%s:%s]: %s (%s)", IF_NAME (nbr->oi),
 775                inet_ntoa (nbr->router_id),
 776                LOOKUP (ospf_nsm_state_msg, nbr->state),
 777                ospf_nsm_event_str [event]);
 778
 779   next_state = NSM [nbr->state][event].next_state;
 780
 781   /* Call function. */
 782   if (NSM [nbr->state][event].func != NULL)
 783     {
 784       int func_state = (*(NSM [nbr->state][event].func))(nbr);
 785
 786       if (NSM [nbr->state][event].next_state == NSM_DependUpon)
 787         next_state = func_state;
 788       else if (func_state)
 789         {
 790           /* There's a mismatch between the FSM tables and what an FSM
 791            * action/state-change function returned. State changes which
 792            * do not have conditional/DependUpon next-states should not
 793            * try set next_state.
 794            */
 795           zlog_warn ("NSM[%s:%s]: %s (%s): "
 796                      "Warning: action tried to change next_state to %s",
 797                      IF_NAME (nbr->oi), inet_ntoa (nbr->router_id),
 798                      LOOKUP (ospf_nsm_state_msg, nbr->state),
 799                      ospf_nsm_event_str [event],
 800                      LOOKUP (ospf_nsm_state_msg, func_state));
 801         }
 802     }
 803
 804   assert (next_state != NSM_DependUpon);
 805
 806   /* If state is changed. */
 807   if (next_state != nbr->state)
 808     {
 809       nsm_notice_state_change (nbr, next_state, event);
 810 #ifdef HAVE_SNMP
 811       int send_trap_virt = 0;
 812       int send_trap = 0;
 813       /* Terminal state or regression */
 814       if ((next_state == NSM_Full)
 815               || (next_state == NSM_TwoWay)
 816               || (next_state < nbr->state))
 817       {
 818           /* ospfVirtNbrStateChange */
 819           if (nbr->oi->type == OSPF_IFTYPE_VIRTUALLINK)
 820               send_trap_virt = 1;
 821           /* ospfNbrStateChange trap  */
 822           else
 823               /* To/From FULL, only managed by DR */
 824               if (((next_state != NSM_Full) && (nbr->state != NSM_Full))
 825                       || (nbr->oi->state == ISM_DR))
 826                   send_trap = 1;
 827       }
 828 #endif
 829       nsm_change_state (nbr, next_state);
 830
 831 #ifdef HAVE_SNMP
 832       if (send_trap_virt) {
 833           ospfTrapVirtNbrStateChange(nbr);
 834       } else if (send_trap) {
 835           ospfTrapNbrStateChange(nbr);
 836       }
 837 #endif
 838     }
 839
 840   /* Make sure timer is set. */
 841   nsm_timer_set (nbr);
 842
 843   /* When event is NSM_KillNbr, InactivityTimer or LLDown, the neighbor
 844    * is deleted.
 845    *
 846    * Rather than encode knowledge here of which events lead to NBR
 847    * delete, we take our cue from the NSM table, via the dummy
 848    * 'Deleted' neighbour state.
 849    */
 850   if (nbr->state == NSM_Deleted)
 851     ospf_nbr_delete (nbr);
 852
 853   return 0;
 854 }
 855
 856 /* Check loading state. */
 857 void
 858 ospf_check_nbr_loading (struct ospf_neighbor *nbr)
 859 {
 860   if (nbr->state == NSM_Loading)
 861     {
 862       if (ospf_ls_request_isempty (nbr))
 863         OSPF_NSM_EVENT_SCHEDULE (nbr, NSM_LoadingDone);
 864       else if (nbr->ls_req_last == NULL)
 865         ospf_ls_req_event (nbr);
 866     }
 867 }